Identificación y sensibilidad antibiótica directas desde el hemocultivo positivo para bacilos gram negativos. Rendimiento comparativo de los sistemas Vitek 2C y Phoenix / Direct identification and susceptibility testing from positive blood cultures. A head-to-head performance comparison between Vitek 2C and Phoenix systems / Identificação e sensibilidade antibiótica diretas a partir da hemocultura positiva para bacilos gram negativos. Desempenho comparativo dos sistemas Vitek 2C e Phoenix

Resumen El objetivo de este estudio fue comparar los resultados de las pruebas de identificación y sensibilidad antimicrobiana obtenidos por los sistemas Vitek 2C (bioMérieux, Francia) y Phoenix (Becton Dickinson, EE.UU.) directamente a partir de hemocultivos positivos. Se realizó un estudio observacional prospectivo en el Hospital Naval Pedro Mallo de Buenos Aires, Argentina, que incluyó 70 bacteriemias monomicrobianas por gram negativos. Se obtuvo una identificación correcta por Vitek® 2C y por Phoenix del 100% y 97% respectivamente [p: no significativa (NS)]. La concordancia categórica para todos los antimicrobianos fue 97,1% y 98,1% (p: NS) con Vitek 2C y con Phoenix respectivamente. El tiempo medio para obtener un resultado fue de 10,19 h y 13,8 h (p: NS), respectivamente. Vitek 2C y Phoenix son herramientas importantes, rápidas y confiables para la identificación y las pruebas de sensibilidad realizadas directamente a partir de hemocultivos positivos.

Abstract The aim of this study was to compare the results of identification and antimicrobial susceptibility tests obtained by the Vitek 2C (bioMérieux, France) and Phoenix (Becton Dickinson, USA) systems directly from positive blood cultures. A prospective observational study was performed at the Pedro Mallo Navy Hospital in Buenos Aires, Argentina, which included 70 monomicrobial bacteremias by gram negative rods. Correct identification by Vitek® 2C and Phoenix was 100% and 97%, respectively [p: not significant (NS)]. Categorical agreement for all antimicrobials was 97.1% and 98.1% (p: NS) with Vitek 2C and Phoenix, respectively. The mean time to result was 10.19 h and 13.8 h (p: NS), respectively. Vitek 2C and Phoenix are important, rapid and reliable tools for identification and susceptibility testing when performed directly from positive blood cultures.

Resumo O objetivo deste estudo foi comparar os resultados dos testes de identificação e de suscetibilidade antimicrobiana obtidos pelos sistemas Vitek 2C (bioMérieux, França) e Phoenix (Becton Dickinson, EUA) diretamente a partir de culturas de sangue positivas. Foi realizado um estudo observacional prospectivo no Hospital Naval Pedro Mallo em Buenos Aires, Argentina, incluindo 70 bacteriemias monomicrobianas devido a gram negativos. A identificação correcta por Vitek® 2C e Phoenix obtida foi de 100% e 97% respectivamente [p: não significativo (NS)]. O acordo categórico para todos os antimicrobianos foi de 97,1% e 98,1% (p: NS) com Vitek 2C e Phoenix respectivamente. O tempo médio para obter o resultado foi de 10,19 h e 13,8 h (p: NS), respectivamente. Vitek 2C e Phoenix são ferramentas importantes, rápidas e fiáveis para a identificação e testes de sensibilidade realizados diretamente a partir de hemoculturas positivas.

Antibióticos en desarrollo para bacilos gram negativos multirresistentes / Antibiotics in development for multiresistant gram-negative bacilli

El rápido incremento en las resistencias a los antibióticos entre los bacilos gram negativos (BGN), especialmente en cepas de enterobacterias, P. aeruginosa y A. baumannii, con elevados patrones de resistencia, plantea una enorme amenaza para los sistemas de salud en todo el mundo. En la última década diferentes antibióticos han sido desarrollados contra patrones de resistencia, algunos de los cuales combinan un β-lactámico junto con un inhibidor de β-lactamasa, mientras que otros utilizan inhibidores no β-lactámicos. La mayoría de ellos presenta una adecuada actividad in vitro sobre varias β-lactamasas de clase A, C y D de Ambler. Sin embargo, combinaciones como ceftazidime/avibactam, ceftolozano/tazobactam y meropenem/vaborbactam no presentan actividad contra metalo-β-lactamasas. Nuevas combinaciones como aztreonan/AVI, cefepime/zidebactam, o modernas cefalosporinas como cefiderocol, presentan eficacia contra casi la totalidad de las metalo-β-lactamasas. Aunque algunas de estas combinaciones ya están aprobadas y en fase de comercialización, muchas de ellas aún deben definir su lugar dentro del tratamiento de microorganismos con resistencia elevada a través de estudios clínicos (AU)

The rapid increase in antibiotic (ATB) resistance among Gram-negative bacilli(BGN), especially in strains of Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii, with high resistance patterns (XDR), poses a huge threat to health systems worldwide. In the last decade, different ATBs have been developed against XDR, some of which combine a lactam β along with a β-lactamase inhibitor, while others use non-β-lactam inhibitors. Most of them have adequate “in vitro” activity on several β-lactamases of class A, C and D of Ambler. However, combinations such as Ceftazidime/avibactam, Ceftolozane/Tazobactam and Meropenem/vaborbactam have no activity against metallo-β-lactamases(MβL). New combinations such as Aztreonan/AVI, Cefepime/Zidebactam, or new cephalosporins such as Cefiderocol, have efficacy against MβL enzymes. Although some of these combinations are already approved and in the commercialization phase, many of them have yet to define their place within the treatment of microorganisms with high resistance through clinical studies (AU)

Antibiotics in development for multiresistant gram-negative bacilli.

The rapid increase in antibiotic(ATB) resistance among Gram-negative bacilli(BGN), especially in strains of Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii, with high resistance patterns (XDR), poses a huge threat to health systems worldwide. In the last decade, different ATBs have been developed against XDR, some of which combine a lactam ß along with a ß-lactamase inhibitor, while others use non-ß-lactam inhibitors. Most of them have adequate "in vitro" activity on several ß-lactamases of class A, C and D of Ambler. However, combinations such as Ceftazidime/avibactam, Ceftolozane/Tazobactam and Meropenem/vaborbactam have no activity against metallo-ß-lactamases(MßL). New combinations such as Aztreonan/AVI, Cefepime/Zidebactam, or new cephalosporins such as Cefiderocol, have efficacy against MßL enzymes. Although some of these combinations are already approved and in the commercialization phase, many of them have yet to define their place within the treatment of microorganisms with high resistance through clinical studies.

Impacto de un programa de vigilancia activa y medidas de control de infecciones sobre la incidencia de bacilos gram negativos resistentes a carbapenems en una unidad de cuidados intensivos

Resumen Las infecciones hospitalarias causadas por bacilos gram negativos resistentes a carbapenems (BGNCR) están asociadas al aumento de morbimortalidad y gasto sanitario. La identificación mediante cultivos de vigilancia y las medidas de control de infecciones permiten reducir su diseminación. El objetivo del estudio fue evaluar el impacto de un programa de vigilancia integrado a protocolos de control de infecciones sobre la incidencia de BGNCR y conocer su epidemiología molecular en una unidad de cuidados intensivos. Se realizaron auditorías seguidas de un programa de cultivo de vigilancia activa y caracterización molecular de BGNCR, antes y después de la implementación de programas de prevención y control de infecciones. El screening microbiológico se realizó en medios cromogénicos; la caracterización molecular de p-lactamasas (blaKPC, bla0XA-48-like, blaVIM, blaiMP, blaNDM, blaSHV y blaCTx-M) por PCR y la tipificación molecular por PFGE y MLST para Klebsiella pneumoniae. El protocolo desarrollado permitió reducir la colonización global de 16,92% al 9,67%. La diseminación de K. pneumoniae fue a expensas de diversos clones portadores de KPC-2 asociada a BLEE SHV-2 y CTX-M-15, y distribuidos en varios secuenciotipos (ST17, ST13, ST2256, ST353); no se observó persistencia de un clon particular y ningún aislamiento presentó factores de virulencia asociados a hipervi-rulencia. Los aislamientos de Acinetobacter baumannii fueron mayoritariamente productores de IMP-1. El análisis PFGE individualizó 3 clusters, asumiendo que la diseminación fue clonal.

Abstract Hospital-acquired infections caused by carbapenem-resistant Gram-negative bacteria (CRGNB) have been increasingly reported worldwide and are associated with high rates of mortality especially in intensive care units(ICUs). Early identification through rectal surveillance cultures and implementation of infection control measures(ICM) including contact precautions, staff education on cleaning and hand hygiene may reduce the spread of these microorganisms. The aim of this work was to assess the impact of enhanced ICM on CRGNB colonization and to describe the molecular epidemiology of these bacteria in a polyvalent ICU in a tertiary level hospital. A prospective study including audits and active surveillance culture program, with molecular characterization, was conducted before and after the implementation of prevention programs and infection control measures. Microbiological screening was performed in chromogenic media; PCR targeting p-lactamases genes (ó/qkpc, óíQndm, blaviM and blaoxA-48, blasHv and ó/qctx-m), molecular typing by PFGE; and MLST in K. pneumoniae were performed. CRGNB colonization was reduced from 16.92% to 9.67% upon implementing the infection control measures. In K. pneumoniae the most frequent carbapenemase type was KPC-2 associated with SHV-2 and CTX-M-15, and was disseminated in various STs (ST17, ST13, ST2256, ST353); there was no persistence of particular clones and virulence factors showed no association with hypervirulence. IMP-1 carbapenemase predominated in A. baumannii and the PFGE analysis individualized 3 clusters, assuming that the dissemination in the ICU was clonal. The early detection of patients colo-nized with CRBGN by using epidemiological surveillance cultures and the implementation of prophylactic measures are key to reducing the incidence of these microorganisms.

El problema de la multi-resistencia en bacilos gram-negativos en las unidades de cuidados intensivos: estrategias de tratamiento y prevención / The problem of multi-resistance in gram-negative bacilli in intensive care units: Treatment and prevention strategies

El aumento global de infecciones causadas por bacilos gram-negativos multi-resistentes (BGN-MR), lo cual incluye a los carbapenemes, supone uno de los grandes retos actuales en materia de sanidad. Esto incluye Enterobacterales productores de β-lactamasas de espectro extendido, productoras de AmpC desreprimida o Enterobacterales productores de carbapenemasas, así como BGN-MR no fermentadores como Pseudomonas aeruginosa o Acinetobacter baumannii. En Pseudomonas aeruginosa predominan otros mecanismos de resistencias diferentes a las β-lactamasas tales como bombas de expulsión o pérdida de porinas. A. baumannii presenta con frecuencia varios de estos mecanismos de resistencia. La mortalidad es elevada especialmente si el tratamiento empírico es inadecuado. En este capítulo se revisan las estrategias de tratamiento haciendo hincapié en las herramientas para identificar los pacientes en los que estaría justificado tratamiento antibiótico empírico para cubrir BGN-MR, la importancia de la optimización de la administración de estos antibióticos, así como las estrategias de prevención para evitar su diseminación desde pacientes colonizados o infectados por un BGN-MR (AU)

The rise of infections caused by multi-resistant gram-negative bacilli (MR-GNB), which includes carbapenems, represents one of the major current challenges worldwide. These MR-GNB include extended spectrum β-lactamase-producing Enterobacterales, derepressed AmpC-producing or carbapenemase-producing Enterobacterales as well as non-fermenting Gram-negative bacilli such as Pseudomonas aeruginosa or Acinetobacter baumannii. P. aeruginosa predominantly exhibits other resistance mechanisms different to β-lactamases such as expulsion pumps or loss of porins. A. baumannii frequently presents several of these resistance mechanisms. Mortality is high especially if empirical treatment is inadequate. In this review, treatment strategies are revised, describing the tools available to identify patients in whom empirical antibiotic treatment would be justified to cover MR-GNB, the importance of optimizing the administration of these antibiotics, as well as prevention strategies to avoid its spread from patients colonized or infected by a MR-GNB (AU)

The problem of multi-resistance in gram-negative bacilli in intensive care units: Treatment and prevention strategies.

The rise of infections caused by multi-resistant gram-negative bacilli (MR-GNB), which includes carbapenems, represents one of the major current challenges worldwide. These MR-GNB include extended spectrum ß-lactamase-producing Enterobacterales, derepressed AmpC-producing or carbapenemase-producing Enterobacterales as well as non-fermenting Gram-negative bacilli such as Pseudomonas aeruginosa or Acinetobacter baumannii. P. aeruginosa predominantly exhibits other resistance mechanisms different to ß-lactamases such as expulsion pumps or loss of porins. A. baumannii frequently presents several of these resistance mechanisms. Mortality is high especially if empirical treatment is inadequate. In this review, treatment strategies are revised, describing the tools available to identify patients in whom empirical antibiotic treatment would be justified to cover MR-GNB, the importance of optimizing the administration of these antibiotics, as well as prevention strategies to avoid its spread from patients colonized or infected by a MR-GNB.

[Impact of an active surveillance program and infection control measures on the incidence of carbapenem-resistant gram-negative bacilli in an intensive care unit]. / Impacto de un programa de vigilancia activa y medidas de control de infecciones sobre la incidencia de bacilos gram negativos resistentes a carbapenems en una unidad de cuidados intensivos.

Hospital-acquired infections caused by carbapenem-resistant Gram-negative bacteria (CRGNB) have been increasingly reported worldwide and are associated with high rates of mortality especially in intensive care units(ICUs). Early identification through rectal surveillance cultures and implementation of infection control measures(ICM) including contact precautions, staff education on cleaning and hand hygiene may reduce the spread of these microorganisms. The aim of this work was to assess the impact of enhanced ICM on CRGNB colonization and to describe the molecular epidemiology of these bacteria in a polyvalent ICU in a tertiary level hospital. A prospective study including audits and active surveillance culture program, with molecular characterization, was conducted before and after the implementation of prevention programs and infection control measures. Microbiological screening was performed in chromogenic media; PCR targeting ß-lactamases genes (blaKPC, blaNDM, blaVIM and blaOXA-48, blaSHV and blaCTX-M), molecular typing by PFGE; and MLST in K. pneumoniae were performed. CRGNB colonization was reduced from 16.92% to 9.67% upon implementing the infection control measures. In K. pneumoniae the most frequent carbapenemase type was KPC-2 associated with SHV-2 and CTX-M-15, and was disseminated in various STs (ST17, ST13, ST2256, ST353); there was no persistence of particular clones and virulence factors showed no association with hypervirulence. IMP-1 carbapenemase predominated in A. baumannii and the PFGE analysis individualized 3 clusters, assuming that the dissemination in the ICU was clonal. The early detection of patients colonized with CRBGN by using epidemiological surveillance cultures and the implementation of prophylactic measures are key to reducing the incidence of these microorganisms.

Presencia de Bacilos Gram-negativos y Candida albicans en provisionales de polimetilmetacrilato (PMM)en pacientes de Clínica Integrada de la Universidad Autónoma de Asunción / Presence of Gram-negative bacilli and Candida albicans in provisional polymethylmethacrylate in patients of the Integrated Clinic of the Autonomous University of Asunción

Las resinas a base de polimetilmetacrilato (PMM) son una solución para la reposición de estructuras dentarias. Este material ha sido muy utilizado debido a su buena estética, pero las rugosidades, grietas y defectos de este material son propicios para la proliferación de microrganismos que podrían constituir un riesgo para la salud de los pacientes. Estudio observacional descriptivo de corte transversal, donde se tomaron muestras de provisorios de PMM de 20 pacientes de la cátedra de Clínica Integrada de Odontología de la Universidad Autónoma de Asunción. Los datos sobre el crecimiento de los microorganismos fueron anotados en planillas Excel para análisis estadísticos. De los 20 pacientes que participaron en esta investigación, 50% fueron de sexo femenino y 50% masculino, el promedio de edad fue de 32,35 años (DE±11,94). Se analizaron un total de 7 pónticos (6 pónticos de 3 piezas y 1 de 6 piezas) y 19 coronas unitarias, el tiempo de permanencia en boca fue de entre 4 a 20 semanas con una media de 8,6 semanas. El 65% de las muestras dio positivo al cultivo microbiológico. En algunas muestras se aislaron más de un género de microorganismos. Se aislaron 5 especies de bacterias Gram-negativas, la más frecuente fue K. pneumoniae con un 40%. Se aisló C. albicans en un 10% de las muestras. En el proceso de elección de los materiales para rehabilitación es fundamental considerar la situación global de cada paciente, pues exponerlos a un material con grandes capacidades retentivas de microrganismos conlleva un peligro

Polymethylmethacrylate (PMM) based resins are a solution for the replacement of dental structures. This material has been widely used due to its good aesthetics, but the roughness, cracks and defects of this material are propitious for the proliferation of microorganisms that could constitute a risk to the health of patients. This was a descriptive cross-sectional observational study, where samples of PMM provisionals were taken from 20 patients of the Department of Integrated Dental Clinic of the Autonomous University of Asunción. Data on the growth of microorganisms were recorded in Excel spreadsheets for statistical analysis. Of the 20 patients who participated in this research, 50% was female and 50% male, and the average age was 32.35 years (SD±11.94). Seven pontics (6 pontics of 3 pieces and 1 of 6 pieces) and 19 unit crowns were analyzed, the time spent in the mouth was between 4 to 20 weeks with an average of 8.6 weeks. Sixty-five percent of the samples tested positive in the microbiological culture. In some samples, more than one genus of microorganisms was isolated. Five species of Gram-negative bacteria were isolated, the most frequent was Klebsiella pneumoniae with 40%. Candida albicans was isolated in 10% of the samples. In the process of choosing materials for rehabilitation, it is essential to consider the overall situation of each patient, since exposing them to a material with high retention capacities of microorganisms carries a danger

Primer reporte de bacterias y dinoflagelados marinos luminiscentes del Parque Nacional Isla del Coco, Costa Rica

Introducción: La bioluminiscencia es la capacidad de ciertos organismos para transformar la energía química en energía lumínica mediante varios procesos bioquímicos. Objetivo: El aislamiento e identificación por primera vez de bacterias luminiscentes en agua marina superficial y la identificación de dinoflagelados luminiscentes marinos del Parque Nacional Isla del Coco, Costa Rica. Metodología: Se colectaron muestras de agua marina obtenida por buceo a 20 m y a nivel superficial de 13 sitios en la Isla del Coco, Costa Rica. Por otra parte, se analizaron muestras de fitoplancton colectadas desde la superficie hasta los 30 m de profundudad en los alrededores de 8 sitios de la Isla del Coco, y se determinaron varias especies luminiscentes pertenecientes a los géneros Ornithocercus y Ceratocorys. Resultados: Se logró obtener 7 aislados bacterianos luminiscentes, se identificaron y caracterizaron bioquímicamente mediante una plataforma automatizada (Vitek) con altos niveles de confianza, se ubicaron taxonómicamente dentro del género Vibrio,2 especies: V. alginolyticus y V. parahaemolyticus, además, algunos aislados presentaron resistencia al antibiótico ampicilina y 100% capacidad hemolítica. Esta investigación muestra evidencia de la presencia de especies microscópicas marinas en Isla del Coco, Costa Rica, capaces de presentar el fenómeno de la luminiscencia, por lo que profundizar en su estudio sería relevante en cuanto a la importancia de estos microorganismos en la producción de metabolitos secundarios y como indicadores de floraciones algales nocivas, por lo que se hace necesario realizar más investigación científica para determinar su potencial biotecnológico. Conclusiones: De la misma forma, los resultados obtenidos en esta investigación sugieren expandir las localidades de colecta y aislamientos de microorganismos luminiscentes, acompañado de una caracterización bioquímica y molecular, con el fin de explorar la diversidad microbiana asociada a eventos de luminiscencia y determinar los ambientes en el que estas especies se desarrollan.

Introduction: Bioluminescence is the ability of certain organisms to transform chemical energy into light energy through various biochemical processes. Objective: Isolation and identification for the first time of luminescent bacteria of superficial marine water, and the identification of marine luminescent dinoflagellates of Isla del Coco National Park, Costa Rica. Methods: Samples of seawater obtained by diving at 20 m and at a surface level of 13 sites were collected. On the other hand, phytoplankton samples collected from the surface up to 30 m deep were analyzed in the surroundings of 8 sites of Cocos Island, and several luminescent species belonging to the genera Ornithocercus and Ceratocorys were determined. Results: Seven luminescent bacterial isolates were obtained, they were identified and characterized biochemically by means of an automated platform (Vitek) with high levels of confidence, they were taxonomically located within the genus Vibrio, 2 species: V. alginolyticus and V. parahaemolyticus, in addition, some isolates presented resistance to the antibiotic ampicillin and 100% hemolytic capacity. This research shows evidence of the presence of marine microscopic species in Cocos Island, Costa Rica, capable of presenting the phenomenon of luminescence, so that further study would be relevant in terms of the importance of these microorganisms in the production of metabolites secondary and as indicators of harmful algal blooms, so it is necessary to conduct more scientific research to determine their biotechnological potential. Conclusions: In the same way, the results obtained in this investigation suggest expanding the collection and isolation of luminescent microorganisms, accompanied by a biochemical and molecular characterization, in order to explore the microbial diversity associated with luminescence events and determine the environments in which that these species develop.

Prevalência, susceptibilidade antimicrobiana e virulência de bacilos Gram-negativos e enterococos isolados do biofilme subgengival associado à doenca periodontal' / Prevalence, antimicrobial susceptibility and virulence of Gram-negative bacilli and enterococci isolated from subgingival biofilm associated with periodontal disease

Objetivos: A cavidade oral pode atuar como reservatório de vários patógenos de importância clínica, incluindo bacilos Gram-negativos (BGN) e Enterococcus spp. Essas espécies podem ainda aumentar em uma condição disbiótica, como ocorre nas doenças periodontais. Assim, este estudo teve como objetivo determinar a prevalência, susceptibilidade antimicrobiana e presença de fatores de virulência de BGN e enterococos isolados do biofilme subgengival de indivíduos com diferentes condições periodontais, correlacionando esses achados com parâmetros clínicos e composição da microbiota subgengival. Métodos: Na análise dos BGN, amostras de biofilme subgengival foram obtidas de indivíduos com Saúde Periodontal (SP, n=81), Gengivite (G, n=74) e Periodontite (P, n=207); para Enterococcus spp., amostras foram coletadas de 139 indivíduos com SP, 103 com G e 305 com P. As amostras foram cultivadas em meio seletivo e as colônias isoladas e identificadas por MALDI-ToF. A susceptibilidade antimicrobiana foi determinada por disco-difusão (CLSI); já os genes de virulência de enterococos e genes codificadores de ESBL e carbapenemases em BGN foram pesquisados por PCR. A produção de ESBL e carbapenemases por BGN foi avaliada pelo teste de sinergia de disco duplo e hidrólise de imipenem por espectrofotometria, respectivamente. A microbiota subgengival desses indivíduos foi determinada pelo Checkerboard. Diferenças entre os grupos foram avaliadas pelos testes de KruskalWallis, Mann-Whitney e Qui-quadrado. Resultados: BGN foram isolados em 36.2% das amostras, com maior prevalência (p<0,001) em pacientes com P (46.4%) em comparação com SP (22.2%) e G (22.9%). Pseudomonas aeruginosa (27.5%), Enterobacter cloacae (16.8%) e Enterobacter asburiae (10.7%) foram as espécies mais predominantes. Resistência/sensibilidade reduzida a ≥ 1 antimicrobiano foi encontrada em 60% dos BGN, mas apenas 4.6% eram multirresistentes. Altas taxas de resistência (>40%) foram observadas na família Enterobacteriacea para cefoxitina, cefalotina, amoxicilina- clavulanato e cefazolina. Uma única cepa de K. pneumoniae apresentou resistência/sensibilidade reduzida ao imipenem, embora o fenótipo ESBL e a detecção dos genes codificadores de beta-lactamases foram negativos. Enterococcus spp. foram isolados em 7.4% de todas as amostras, 53.7% eram E. faecalis. Essas espécies foram mais predominantes na P (9.8%) e G (7.8%) do que na SP (2.2%, p< 0,05); entretanto não houve correlação com os níveis de gravidade da P. Altas taxas de resistência/susceptibilidade reduzida foram observadas para ciprofloxacina, eritromicina e rifampicina. Os fatores de virulência mais predominantes incluíram ace, asa e esp, todos relacionados à formação de biofilme e colonização. F. nucleatum foi mais prevalente na microbiota de indivíduos enterococos +. Por outro lado, Dialister pneumosintes foi pouco detectado em indivíduos portadores de enterococos bopD+. Estreptococos orais foram prevalentes (>70%) na microbiota de pacientes que apresentavam enterococos suceptíveis à doxiciclina (p<0,05), frequentemente bopD- e esp- (p<0,01). Conclusão: Uma prevalência elevada de BGN da família Enterobacteriacea com resistência a cefalosporinas e penicilina é observada na microbiota subgengival de indivíduos com P. Enterococcus spp., principalmente E. faecalis são pouco frequentes na microbiota subgengival associada à SP, porém aumentam significativamente nas doenças periodontais. Os mesmos apresentam diversos genes de virulência compatíveis com destruição tecidual, bem como resistência a antimicrobianos de uso na clínica periodontal, o que pode limitar uma resposta terapêutica favorável. (AU)

Background/Aim: The oral cavity can act as a reservoir for several pathogens of clinic importance, including Gram-negative bacilli (GNB) and Enterococcus spp. These species may increase even more in a dysbiotic condition as seen in periodontal diseases. Thus, this study aimed to determine the prevalence, antimicrobial susceptibility and virulence factors of GNB and enterococci isolated from subgingival biofilm of individuals with different periodontal conditions, correlating these findings with clinical parameters and the composition of the subgingival microbiot. Methods: For GNB analysis, subgingival biofilm was obtained from individuals with periodontal health (PH, n=81), gingivitis (G, n=74) and periodontitis (P, n=207), whereas for enterococci isolation samples were taken from 139 patients with PH, 103 with G, and 305 with P. Samples were cultivated in selective media and isolated colonies were identified by MALDI-ToF. Antimicrobial susceptibility was determined by CLSI disk diffusion, whereas virulence genes by PCR. Production of ESBL and carbapenemases were evaluated by double disk synergy test and spectrophotometric detection of imipenem hydrolysis, respectively, and ESBL and carbapenemase encoding genes were surveyed by PCR. The subgingival microbiota was determined by checkerboard. Differences among groups were examined by Chi-square, Kruskal-Wallis or Mann-Whitney tests. Results: GNB were isolated from 36.2% of all samples, with a significantly greater prevalence (p<0.001) in P patients (46.4%) compared to PH (22.2%) and G (22.9%). Pseudomonas aeruginosa (27.5%), Enterobacter cloacae (16.8%) and Enterobacter asburiae (10.7%) were the most predominant species. Resistance/reduced sensitivity to ≥ 1 antimicrobial was found in 60% of GNB, but only 4.6% were multidrug resistant. High resistance rates (>40%) were seen in the Enterobacteriaceae family for cefoxitin, cephalotin, amoxicillin-clavulanate, and cefazolin. One strain of K. pneumoniae showed resistance/reduced sensitivity to imipenem, although the ESBL-phenotype and PCR targeting beta-lactamase encoding genes were negative. Enterococcus spp. were isolated from 7.4% of all samples; 53.7% were E. faecalis. Enterococci were more predominant in P (9.8%) and G (7.8%) samples than PH (2.2%; p<0.05), however there were no associations with distinct levels of disease severity. High rates of low susceptibility/resistance were seen for ciprofloxacin, erythromycin and rifampicin. Predominant virulence factors included ace, asa and esp, all related to colonization and biofilm formation. F. nucleatum was prevalent in the microbiota of enterococci+ individuals. In contrast, lower frequency of Dialister pneumosintes was found in patients carrying bopD+ enterococci. Oral streptococci were prevalent (>70%) in the microbiota of patients carrying enterococci susceptible to doxycycline (p<0.05), which were also frequently bopD- and esp- (p<0.01). Conclusion: A high prevalence of GNB of the Enterobacteriacea family, resistant to cephalosporins and penicillins is observed in the subgingival microbiota of patients with P, Enterococcus spp., mainly E.faecalis are not commonly detected in the healthy-related subgingival microbiota, however their frequency increases significantly in patients with periodontal diseases. These species carry several genes related to tissue destruction, as well as resistance to antimicrobials routinely used in the periodontal clinic, which may hinder a successful therapeutic response. (AU)

Colonization and risk of infection by multidrug-resistant bacteria in hemodialysis patients: a topic of concern / Colonización e infección por bacterias multirresistentes en pacientes en hemodiálisis: un tema de preocupación

Antimicrobial resistance worsens the prognosis in patients with chronic diseases. Patients on hemodialysis have infection rates that exceed those reported in other types of patients. Colonization has been suggested as a risk factor for the development of infections. However, the majority of the studies that have evaluated this association have methodological limitations that have called into question the validity of the results; such as the lack of use of molecular methods to confirm that the colonizing species are the same as that which causes infection, the measurement of exposure only at the beginning of the study, the absence of follow-up, the evaluation of bacteremia as the only important outcome and the focus only on Staphylococcus aureus, without including other resistant bacteria of clinical importance such as multidrug-resistant Gram-negative bacteria. This lead to the need to use molecular epidemiology methods for refine the association between colonization and infection in endemic countries like Colombia, where the high rates of antimicrobial resistance demand accurate prevention strategies in susceptible patients.

La resistencia antimicrobiana empeora el pronóstico en pacientes con enfermedades crónicas. Los pacientes en hemodiálisis son un grupo particularmente afectado con porcentajes de infección bacteriana que exceden las reportadas en otro tipo de pacientes. La colonización ha sido sugerida como un factor de riesgo para el desarrollo de infecciones. Sin embargo, los estudios que han evaluado esta asociación presentan limitaciones metodológicas que han cuestionado la validez de los resultados; como la falta de utilización de métodos moleculares que confirmen que la especie que coloniza es la misma que causa infección, la medición de la exposición solo al inicio del estudio, la ausencia de seguimiento y la evaluación de bacteriemia como el único desenlace de importancia. Así mismo, la mayoría de los estudios se han enfocado solo en Staphylococcus aureus sin incluir otras bacterias resistentes de importancia clínica como son los bacilos Gram negativos multirresistentes. Lo anterior lleva a la necesidad de utilizar métodos de epidemiología molecular que permitan refinar el análisis de la asociación entre colonización e infección, más aún en países endémicos como Colombia, en el que los altos porcentajes de resistencia demandan estrategias de prevención más certeras en pacientes susceptibles.

Endocarditis infecciosa por bacilos gram negativos no HACEK. Experiencia en un centro de alta complejidad de la República Argentina (1998-2016) / Infective endocarditis due to non-HACEK gram-negative bacilli in a Level III cardiovascular center in Argentina (1998-2016)

Los bacilos gram negativos (BGN) que no pertenecen al grupo HACEK son una causa infrecuente de endocarditis infecciosa. Los aspectos epidemiológicos, diagnósticos y pronósticos de esta entidad son poco conocidos y la experiencia aún es limitada. Nuestros objetivos fueron analizar las características clínicas y microbiológicas de las endocarditis infecciosas (EI) por BGN no HACEK diagnosticadas en un centro de alta complejidad de Argentina en el período 1998-2016 y conocer su evolución hospitalaria, a fin de compararlas con las EI debidas a otros microorganismos.

Non-HACEK Gram-negative bacilli are a rare cause of infective endocarditis. Epidemiological, diagnostic and prognostic aspects of this entity are little known, and there is limited experience. The aim of this study was to analyze the clinical, microbiological and in-hospital outcomes of non-HACEK Gram negative bacilli endocarditis and to compare them with those due to other microorganisms.

[Infective endocarditis due to non-HACEK gram-negative bacilli in a Level III cardiovascular center in Argentina (1998-2016)]. / Endocarditis infecciosa por bacilos gram negativos no HACEK. Experiencia en un centro de alta complejidad de la República Argentina (1998-2016).

Non-HACEK Gram-negative bacilli are a rare cause of infective endocarditis. Epidemiological, diagnostic and prognostic aspects of this entity are little known, and there is limited experience. The aim of this study was to analyze the clinical, microbiological and in-hospital outcomes of non-HACEK Gram negative bacilli endocarditis and to compare them with those due to other microorganisms.

Avaliação da multirresistência a antibióticos e produção de ESBL e carbapenemases em bacilos gram-negativos de efluente hospitalar e urbano / Evaluation of antibiotic multi-resistance and production of ESBL and carbapenemases in gram-negative bacilli of hospital and urban effluent

A multirresistência aos antibióticos observada em bacilos gram-negativos é um grave problema de saúde pública devido a alta morbidade e mortalidade apresentada, especialmente em instituições assistenciais de saúde. Como consequência do intenso uso de antibióticos, a multirresistência a esses fármacos é principalmente mediada por enzimas hidrolisantes, onde destaca-se as enzimas ?-lactamases, principal mecanismo de resistência aos ?-lactâmicos verificado em bacilos gram-negativos. Os esgotos de origem hospitalar e de estações de tratamento de esgoto (ETE) são considerados como reservatórios de bactérias multirresistentes pela presença de antibióticos que as selecionam e por favorecem a transmissão de determinantes de resistência. Nesse sentido, o presente estudo objetivou avaliar a multirresistência a antibióticos e a produção de enzimas ?-lactamases em bacilos gram-negativos isolados de efluente hospitalar e da estação de tratamento de esgoto, na cidade de Ribeirão Preto, SP. No hospital terciário, amostras de esgotos foram coletadas dos ambulatórios, das enfermarias e da junção do esgoto hospitalar. Na ETE, amostras foram coletadas na caixa de entrada do esgoto bruto e após ao tratamento. Dez microlitros foram semeados em ágar MacConkey, SalmonellaShigella, Cetrimide e TCBS e a identificação dos bacilos gram-negativos foi realizada pelo kit Bactray®. O teste de susceptibilidade aos antibióticos foi realizado pelo método de discodifusão em ágar. A detecção fenotípica de bacilos produtores de ESBL foi realizada pelos testes de sinergia de disco-duplo e disco combinado com ácido clavulânico, e para detecção de isolados produtores de carbapenemases foi utilizado os testes de disco combinado com ácido fenilborônico e EDTA e o teste Blue Carba. A PCR foi utilizada para amplificação dos genes codificadores de ESBL e carbapenemases. No total, 45 bacilos gram-negativos foram isolados, sendo as espécies Klebsiella pneumoniae e Pseudomonas aeruginosa as de maiores prevalências. Ampla resistência foi verificada aos antibióticos ?-lactâmicos, sendo a resistência ao aztreonam, a cefepime e a cefotaxima mais expressiva nos isolados do esgoto hospitalar, com diferenças estatisticamente significante (p<0,05). O fenótipo multidroga resistente foi atribuído a 33,3%, nos isolados exclusivamente do esgoto hospitalar, com diferença estatisticamente significante (p = 0,0025) em relação aos isolados do esgoto da ETE. Genes de ?-lactamases foram encontrados em 35,6% das bactérias, sendo o blaKPC e blaTEM os de maiores ocorrências, ambos em 17,8% dos isolados, e os genes blaSHV e blaCTX-M em 13,3% e 8,9%. Somente em um isolado de Enterobacter cloacae no esgoto tratado da ETE foi identificado o gene blaSHV, os demais isolados portadores dos genes de ?-lactamases foram encontrados no esgoto hospitalar. Os dados obtidos neste estudo são importantes levando em consideração que no Brasil o esgoto hospitalar pode ser lançado in natura na rede coletora municipal, no entanto, acredita-se que tal permissão favorece a disseminação da multirresistência bacteriana, posto que, os resultados demonstram alta frequência de bactérias portadoras de genes de resistência a antibióticos no esgoto hospitalar estudado. Assim, a implementação do tratamento de efluentes hospitalares, especialmente os de hospitais terciários, e adicionalmente ao tratamento da ETE evitaria a propagação dessas bactérias no ambiente e de impactar negativamente os recursos hídricos

Antibiotic multi-resistance observed in Gram-negative bacilli is a serious public health problem due to high morbidity and mortality, especially in health care institutions. As a consequence of the intense use of antibiotics, multi-resistance to these drugs is mainly mediated by hydrolyzing enzymes, in which ?-lactamases, the main ?-lactam resistance mechanism observed in Gramnegative bacilli, are prominent. Hospital sewage and wastewater treatment plants (WWTP) are considered reservoirs of multiresistant bacteria by the presence of antibiotics that select these bacteria and favor the transmission of resistance determinants. In this sense, the present study aimed to evaluate the antibiotics multi-resistance and the production of ?-lactamase enzymes in Gram-negative bacilli isolated from hospital effluent and the wastewater treatment plants in Ribeirão Preto city, SP. In the tertiary hospital, sewage samples from the outpatient clinics, rooms patients and the hospital sewage junction were collected. In the WWTP, raw and treated sewage were collected. Ten microliters were seeded on MacConkey, Salmonella-Shigella, Cetrimide and TCBS agar and the identification of Gram-negative bacilli was performed by the Bactray® kit. Antibiotic susceptibility test was performed by agar-diffusion method. Phenotypic detection of ESBL-producing bacilli was performed by double-disc and discsynergy tests combined with clavulanic acid, and for the detection of carbapenemase-producing isolates the combined disk tests with phenylboronic acid and EDTA and Blue Carba test were used. PCR amplification of ESBL and carbapenemases-encoding genes was used. In total, 45 Gram-negative bacilli were isolated, and Klebsiella pneumoniae and Pseudomonas aeruginosa being the most prevalent. Extensive resistance was verified to ?-lactam antibiotics and resistance to aztreonam, cefepime and cefotaxime was more pronounced in hospital sewage isolates, with statistically significant differences (p<0.05). Multidrug-resistant phenotype was attributed to 33.3% in isolates exclusively from hospital sewage, with a statistically significant difference (p = 0.0025) in relation to the sewage isolates from the WWTP. ?-lactamase genes were found in 35.6% of the bacteria, with blaKPC and blaTEM having the highest occurrences, both in 17.8% of the isolates, and the blaSHV and blaCTX-M genes in 13.3% and 8, 9%. Only in an isolate of Enterobacter cloacae in the treated sewage from WWTP was the blaSHV gene identified, the other isolates carrying the ?-lactamases genes were found in hospital sewage. The data obtained in this study are important considering that in Brazil the hospital sewage can be released in nature in municipal collection network, however, it is believed that such permission favors the dissemination of bacterial multi-resistance, since, the results show high frequency of bacteria carrying antibiotic resistance genes in the hospital sewer studied. Thus, the implementation of treatment of hospital effluents, especially those in tertiary hospitals, and in addition to the treatment of WWTP would prevent the spread of these bacteria in the environment and negatively impact water resources

Bacterial resistance in bats from the Phyllostomidae family and its relationship with unique health / Resistência bacteriana em morcegos da família Phyllostomidae e sua relação com a saúde única

The Phyllostomidae family is important among the bats found in Brazil, with several species and diverse eating habits, and is the only one to have frugivorous representatives. These bats can be found in urban and in wild life environments in search for the best reproductive and feeding conditions. The versatility of environments can be associated with the incidence and/or distribution of some diseases through pathogenic agents. The present paper has the purpose to identify the oral and perianal microbiota and to detect the bacterial resistance of frugivorous bats captured near communities inhabited by humans in the northwestern region of the state of Paraná. A total of 68 bats were captured, belonging to four species of the Phyllostomidae family, namely Artibeus lituratus, Artibeus planirostris, Carollia perspicillata and Sturnira lillium, originated from forest fragments in the micro region of Umuarama, state of Paraná. A total of 64 isolates from oral bacteria and 39 from perianal region were submitted to identification. They were later submitted to a susceptibility test to 22 human and veterinary antimicrobials. The most prevalent bacteria were Escherichia coli 33.3% in the oral region, and 35.90% in the perianal region, Enterobacter aerogenes 12.7% and 5.13%, Enterobacter agglomerans 7.9% and 10.25%, and Serratia liquefaciens 9.5% and 5.13% in the oral and perianal region respectively. All bat species studied had resistant strains, with a few of them presenting multi-resistance to antimicrobials. The species with the highest multi-resistance index to antimicrobials was Carollia perspicillata, with three strains of the oral region resistant to 15 antimicrobials; it also presented two strains in the perianal region, which were resistant to 13 and 10 antimicrobials respectively. Based on the results found, it is possible to conclude that the oral and perianal microbiota of bats is composed of several enterobacterial species resistant to one or several antimicrobials used in human and veterinarian medicine. This is an issue and a future warning for unique health, since high percentages of resistance were found against antimicrobials broadly used, such as ampicillin, amoxicillin and amoxicillin+clavulonate.(AU)

A família Phyllostomidae se destaca entre as famílias de morcegos encontrados no Brasil, com diversificadas espécies e hábitos alimentares, sendo a única a apresentar representantes frugívoros, podendo ser encontrada tanto em meio urbano, como de vida livre, em busca de melhores condições reprodutivas e alimentares. Essa versatilidade de ambientes pode estar associada à incidência e/ou distribuição de determinadas doenças por agentes patogênicos. O presente trabalho objetivou identificar a microbiota oral e perianal e detectar a resistência bacteriana em morcegos frugívoros capturados próximos às comunidades habitadas pelo homem na região noroeste do estado do Paraná. Foram capturados 68 morcegos, de quatro espécies da família Phyllostomidae, são eles Artibeus lituratus, Artibeus planirostris, Carollia perspicillata e Sturnira lillium, oriundos de fragmentos de Mata da microrregião de Umuarama, estado do Paraná. Um total de 64 isolados de bactérias da região oral e 39 da região perianal foram submetidos, identificação e posteriormente teste de susceptibilidade a 22 antimicrobianos de uso humano e veterinário. As bactérias mais prevalentes foram Escherichia coli 33,3% na região da boca e 35,90% na região perianal, Enterobacter aerogenes 12,7% e 5,13%, Enterobacter agglomerans 7,9% e 10,25% e Serratia liquefaciens 9,5% e 5,13% na região da boca e perianal, respectivamente. Todas as espécies de morcegos estudadas apresentaram cepas que foram resistentes, e algumas multirresistência aos antimicrobianos. A espécie que apresentou maior índice de multirresistência aos antimicrobianos foi Carollia perspicillata, com três cepas na região oral resistente a 15 antimicrobianos, e duas na perianal, com resistência a 13 e 10 antimicrobianos respectivamente. Baseados nos resultados encontrados, é possível concluir que a microbiota oral e perianal de morcegos, é composta por diversas espécies de enterobactérias, resistentes a um, ou vários antimicrobianos utilizados na medicina humana e veterinária, tornando-se um problema, e um alerta futuro para a saúde única, uma vez que foram encontrados elevados percentuais de resistência contra antimicrobianos utilizados em larga escala tais como ampicilina, amoxicilina e amoxicilina+clavulonato.(AU)

Bacteriemias por bacilos Gram negativos multirresistentes en neutropénicos febriles con enfermedades hematológicas / Bacteremia due to multiresistant Gram-negative bacilli in febrile neutropenic patients with hematological diseases

Las infecciones por bacilos Gram negativos multiresistentes (BGN-MR) son frecuentes en nuestro hospital. Presentan limitadas opciones terapéuticas e importante impacto en la morbimortalidad y costos. Objetivo: analizar los factoes de riesgo y evolución de las bacteriemias por BGN-MR en pacientes neutropénicos febriles con patologías hematológicas. Materiales y métodos: estudio prospectivo, descriptivo y observacional de los factores de riesgo para BGN-MR en la población descripta. Se realizó análisis univariado y multivariado de variables clínicas, epidemiológicas, microbiológicas y evolutivas. Resultados: El 27 % de los episodios de neutropenia y fiebre cursaron con bacteriemias por BGN, 42 % de ellos fueron producidos por BGN-MR. En el análisis univariado, dichas bacteriemias se asociaron al uso previo de antibióticos; a las bacteriemias de brecha y neutropenias mayores a 7 días. En el análisis multivariado la bacteriemia de brecha mantuvo su significancia estadística (P<0,001; OR: 5,17; IC 95 % 2,1-12,7). Acinetobacter spp fue el BGN-MR más frecuentemente aislado incluso en los pacientes fallecidos. No se detectó el foco en el 45,9 % de los episodios. Los tratamientos inadecuados fueron significativamente más frecuentes en los pacientes con BGN-MR y la mortalidad tanto global como atribuible también se asoció significativamente al tratamiento inadecuado de las bacteriemias por BGN-MR (P<0,04;RR: 2,46;IC 95 % 1,03-5,9 y P< 0,014; RR: 3,02; IC 95 % 1,22-0,45 respectivamente). Conclusiones: Las bacteriemias por BGN-MR son frecuentes en la población estudiada en especial los que han recibido ATB previo y en las que surgen intratratamiento ATB. Recibieron con mayor frecuencia tratamiento empírico inadecuado, lo que se asoció a mayor mortalidad...

Bacterial infections by multiresistant Gram-negative bacilli (BGN-MR) are an increasing problem in our hospital with a major impact on morbidity, mortality and costs. Objective: to analize risk factors and outcome in bacteremia due to multiresistant Gram-negative bacilli in febrile neutropenic patients with hematologic diseases. Material and Methods: We conducted a prospective, descriptive and observational study to describe the risk factors and outcome of BGN-MR bacteremia in these patients. Results: Twenty seven percent of neutropenia and fever episodes had Gram-negative bacilli bacteremia and 42 % of them were caused by BGN-MR. Previous use of antibioteics, breakthrough bacteremia and prolonged neutropenia (<7 days) were significant in univariate analysis. In multivariate analysis only breakthrough bacteremia was significant (P< 0.001; OR 5,17;IC 95 % 2.1-12.7). Acinetobactersppp was the most common BGN-MR isolated in blood-stream infections and in patients who died. The source of infections was unknown in 45,9 % of the episodes. Inadequate empirical therapy was most common in BGN-MR bacteremia and it was associated with increased overall and attributable mortality (P<0.04; RR: 2.46; IC 95 % 1.03-5.9 y P<0.014; RR: 3.02; IC 95 % 1.22-7.45). Conclusions: BGN-MR was frequent in neutropenic patients with hematological diseases specially in those exposed to antibiotics and in breakthroug bacteremia. Inappropiate antimicrobial therapy was common and is associated with adverse outcome...

Presence and antimicrobial profile of Gram-negative facultative anaerobe rods in patients with chronic periodontitis and gingivitis

La periodontitis crónica es una enfermedad infecciosa multifactorial hacen parte de la microflora subgingival. En los últimos años se han realizado estudios para valorar la presencia de bacilos Gramnegativos anaerobios facultativos (enterobacterias) y suimportancia en el desarrollo y rogresión de la periodontitis crónica. El objetivo de este estudio fue determinar la presencia de enterobacterias en pacientes con periodontitis crónica y gingivitis y conocer la susceptibilidad antimicrobiana de los aislamientosclínicos. Se realizó un estudio observacional y descriptivo en elque se incluyeron 64 pacientes con periodontitis crónica y 22 pacientes con gingivitis. Las muestras tomadas en el surco gingival con conos de papel se depositaron en caldo tioglicolato, seincubaron durante 4 horas a 37 oC y se resembraron finalmente en Agar MacConkey. En la identificación de las bacterias se utilizó el sistema API-20E (Biomerieux, France) y la susceptibilidadantimicrobiana se realizó por el método de difusión en disco. En los dos grupos se identificaron 29 especies enterobacterianas, 7 en el grupo con gingivitis y 22 en el grupo con periodontitis crónica. En el grupo de periodontitis crónica las especies masfrecuentes fueron: K. oxytoca n=5, S. liquefaciens n=4 y K.pneumoniaey E. coli con n=3. En el grupo con gingivitis, Erwiniasp tuvo la mayor frecuencia (n=2). Los aislamientos clínicos presentaron níveles muy bajos de sensibilidad a los B-lactamicosampicilina y amoxicilina/ ac.clavulanico, 17.2 y 27.6 por ciento, y la mayor sensibilidad a ciprofloxacina. En conclusión, la alta frecuencia de enterobacterias en pacientes con periodontitis debe conducir a la prevención y a desarrollar terapias mecánicas y antimicrobianas en las cuales se tengan en cuenta, como parte del tratamiento periodontal, los perfiles antimicrobianos reportados.

Presence and antimicrobial profile of Gram-negative facultative anaerobe rods in patients with chronic periodontitis and gingivitis

La periodontitis crónica es una enfermedad infecciosa multifactorial hacen parte de la microflora subgingival. En los últimos años se han realizado estudios para valorar la presencia de bacilos Gramnegativos anaerobios facultativos (enterobacterias) y suimportancia en el desarrollo y rogresión de la periodontitis crónica. El objetivo de este estudio fue determinar la presencia de enterobacterias en pacientes con periodontitis crónica y gingivitis y conocer la susceptibilidad antimicrobiana de los aislamientosclínicos. Se realizó un estudio observacional y descriptivo en elque se incluyeron 64 pacientes con periodontitis crónica y 22 pacientes con gingivitis. Las muestras tomadas en el surco gingival con conos de papel se depositaron en caldo tioglicolato, seincubaron durante 4 horas a 37 oC y se resembraron finalmente en Agar MacConkey. En la identificación de las bacterias se utilizó el sistema API-20E (Biomerieux, France) y la susceptibilidadantimicrobiana se realizó por el método de difusión en disco. En los dos grupos se identificaron 29 especies enterobacterianas, 7 en el grupo con gingivitis y 22 en el grupo con periodontitis crónica. En el grupo de periodontitis crónica las especies masfrecuentes fueron: K. oxytoca n=5, S. liquefaciens n=4 y K.pneumoniaey E. coli con n=3. En el grupo con gingivitis, Erwiniasp tuvo la mayor frecuencia (n=2). Los aislamientos clínicos presentaron níveles muy bajos de sensibilidad a los B-lactamicosampicilina y amoxicilina/ ac.clavulanico, 17.2 y 27.6 por ciento, y la mayor sensibilidad a ciprofloxacina. En conclusión, la alta frecuencia de enterobacterias en pacientes con periodontitis debe conducir a la prevención y a desarrollar terapias mecánicas y antimicrobianas en las cuales se tengan en cuenta, como parte del tratamiento periodontal, los perfiles antimicrobianos reportados.(AU)

Prevalência de bacilos Gram-negativos não fermentadores de pacientes internados em Porto Alegre-RS / Prevalence of non-fermenting Gram-negative bacilli among inpatients from Porto Alegre-RS

INTRODUÇÃO: Os bacilos Gram-negativos não fermentadores (BGNNF) são frequentemente associados às infecções hospitalares. Além da alta incidência, esses microrganismos possuem resistência a diversos antimicrobianos. OBJETIVO: Analisar a prevalência e o perfil de resistência de BGNNF. MÉTODOS: Foram analisados 14.971 laudos de pacientes em um hospital privado de Porto Alegre-RS, no período de maio de 2006 a março de 2008, sem distinção de sexo e idade. RESULTADOS E CONCLUSÃO: Foram isoladas 326 amostras de BGNNF. As espécies mais prevalentes foram: Pseudomonas aeruginosa (65,03 por cento), Acinetobacter baumannii (16,56 por cento) e Stenotrophomonas maltophilia (9,5 por cento). Outras espécies apresentaram índices inferiores a 5 por cento. Os microrganismos foram isolados de diversos sítios infecciosos. Os materiais biológicos que apresentaram maior positividade para esses microrganismos foram o aspirado traqueal (38,34 por cento), o escarro (18,71 por cento) e a urina (15,95 por cento). A resistência bacteriana mostrou-se mais expressiva a tetraciclinas (89,57 por cento) e sulfametoxazol/trimetoprima (79,75 por cento). Os antimicrobianos mais ativos foram polimixina B, com 100 por cento de sensibilidade, e piperaciclina/tazobactam, com 75,2 por cento de sensibilidade.

INTRODUCTION: The non-fermenting Gram-negative bacilli (NFGNB) have been widely associated with nosocomial infections. Not only are these microorganisms highly prevalent but they are also highly resistant to NFGNB. OBJECTIVE: To assess the prevalence and resistance profile of non-fermenting Gram-negative bacilli. METHODS: 14.971 patient reports from a private hospital in Porto Alegre, Rio Grande do Sul, from May/2006 to March/2008 were analyzed. RESULTS AND CONCLUSION: Three hundred twenty-six samples of non-fermenting Gram-negative bacilli were isolated. The most prevalent species were Pseudomonas aeruginosa (65.03 percent), Acinetobacter baumannii (16.56 percent), and Stenotrophomonas maltophilia (9.5 percent). Other species showed rates lower than 5 percent. The microorganisms were isolated from several infectious sites and the biological materials that showed higher positivity were the following: tracheal aspirate (38.34 percent), spittle (18.71 percent) and urine (15.95 percent). Bacterial resistance was higher with tetracyclines (89.57 percent) and sulfamethoxazole/trimethoprim (79.75 percent). The most active antimicrobials were polymyxin B and piperacillin/tazobactam with 100 percent and 75.2 percent sensibility, respectively.

Criterios de ensayo, interpretación e informe de las pruebas de sensibilidad a los antibióticos en los bacilos gram negativos no fermentadores de importancia clínica: recomendaciones de la Subcomisión de Antimicrobianos de la Sociedad Argentina de Bacteriología, Micología y Parasitología Clínicas, Asociación Argentina de Microbiología / Antimicrobial susceptibility testing in clinically relevant non-fermenting gram-negative bacilli: recommendations from the Antimicrobial Agents Subcommittee of the Sociedad Argentina de Bacteriología, Micología y Parasitología Clínicas, Asociación Argentina de Microbiología

En este documento se dan a conocer una serie de recomendaciones para el ensayo, la lectura, la interpretación y el informe de las pruebas de sensibilidad a los antimicrobianos para los bacilos gram negativos no fermentadores (BGNNF) que se aíslan en humanos. Se adoptaron como base las recomendaciones internacionales, las de la Subcomisión de Antimicrobianos de la Sociedad Argentina de Bacteriología, Micología y Parasitología Clínicas y las de un grupo de expertos invitados. Se incluye, además, la nomenclatura actualizada de los BGNNF y la descripción de algunas de sus características individuales, de sus resistencias naturales o habituales a los antimicrobianos de uso clínico y de los mecanismos responsables de tales resistencias. También se indican los agentes antimicrobianos que se deberían ensayar frente a las distintas especies, con la especificación de cuáles deberían ser informados, y su ubicación estratégica en las placas de cultivo para poder detectar los mecanismos de resistencia más frecuentes y relevantes. Por último, se detallan los métodos de detección y de confirmación fenotípica de la presencia de b-lactamasas emergentes en Argentina, como las carbapenemasas clases A y B.

This document contains the recommendations for antimicrobial susceptibility testing of the clinically relevant non-fermenting gram-negative bacilli (NFGNB), adopted after conforming those from international committees to the experience of the Antimicrobial Agents Subcommittee members and invited experts. This document includes an update on NFGNB classification and description, as well as some specific descriptions regarding natural or frequent antimicrobial resistance and a brief account of associated resistance mechanisms. These recommendations not only suggest the antimicrobial drugs to be evaluated in each case, but also provide an optimization of the disk diffusion layout and a selection of results to be reported. Finally, this document also includes a summary of the different methodological approaches that may be used for detection and confirmation of emerging b-lactamases, such as class A and B carbapenemases.