Antimicrobial resistance and plasmid-mediated colistin resistance mechanism of diarrheagenic Escherichia coli recovered from foods in parts of China in 2020 / 中华预防医学杂志

Objective: To investigate the antimicrobial resistance of food-borne diarrheagenic Escherichia coli (DEC) and the prevalence of mcr genes that mediates mobile colistin resistance in parts of China, 2020. Methods: For 91 DEC isolates recovered from food sources collected from Fujian province, Hebei province, Inner Mongolia Autonomous Region and Shanghai city in 2020, Vitek2 Compact biochemical identification and antimicrobial susceptibility testing platform was used for the detection of antimicrobial susceptibility testing (AST) against to 18 kinds of antimicrobial compounds belonging to 9 categories, and multi-polymerase chain reaction (mPCR) was used to detect the mcr-1-mcr-9 genes, then a further AST, whole genome sequencing (WGS) and bioinformatics analysis were platformed for these DEC isolates which were PCR positive for mcr genes. Results: Seventy in 91 isolates showed different antimicrobial resistance levels to the drugs tested with a resistance rate of 76.92%. The isolates showed the highest antimicrobial resistance rates to ampicillin (69.23%, 63/91) and trimethoprim-sulfamethoxazole (59.34%, 54/91), respectively. The multiple drug-resistant rate was 47.25% (43/91). Two mcr-1 gene and ESBL (extended-spectrum beta-lactamase) positive EAEC (enteroaggregative Escherichia coli) strains were detected. One of them was identified as serotype of O11:H6, which showed a resistance profile to 25 tested drugs referring to 10 classes, and 38 drug resistance genes were predicted by genome analysis. The other one was O16:H48 serotype, which was resistant to 21 tested drugs belonging to 7 classes and carried a new variant of mcr-1 gene (mcr-1.35). Conclusion: An overall high-level antimicrobial resistance was found among foodborne DEC isolates recovered from parts of China in 2020, and so was the MDR (multi-drug resistance) condition. MDR strains carrying multiple resistance genes such as mcr-1 gene were detected, and a new variant of mcr-1 gene was also found. It is necessary to continue with a dynamic monitoring on DEC contamination and an ongoing research into antimicrobial resistance mechanisms.

Resistencia a colistina en aislados de Klebsiella pneumoniae resistente a carbapenémicos en un hospital pediátrico de Corrientes / Colistin resistance in carbapenem-resistant Klebsiella pneumoniae isolates from a pediatric hospital from Corrientes, Argentina

INTRODUCCIÓN: Existe un incremento de las infecciones por Klebsiella pneumoniae resistente a carbapenémicos (KPRC) en la población pediátrica y los datos epidemiológicos son limitados. OBJETIVOS: Conocer la frecuencia de KPRC en pacientes pediátricos, determinar la actividad in vitro de colistina y detectar el gen mcr-1 en dichos aislados. MATERIALES Y MÉTODOS: Se estudiaron 220 aislados de K. pneumoniae en un hospital pediátrico durante los años 2018 y 2019. La susceptibilidad antimicrobiana se determinó por microdilución en caldo según CLSI y EUCAST. Los genes blaKPC, blaNDM, blaIMP, blaVIM, blaOXA-48 y mcr-1 se analizaron mediante reacción de polimerasa en cadena (RPC). RESULTADOS: El 9,5% (n: 21) de los aislados fueron caracterizados como KPRC, donde se observó una resistencia a colistina de 47,6% (10/21) con valores de CIM50 de 2 μg/mL y CIM90 de > 4 μg/mL. En todos los aislados de KPRC se caracterizó el gen blaKPC y no se detectó el gen mcr-1. El perfil de resistencia observado en otros antimicrobianos fue el siguiente: gentamicina 100% (n: 21), ciprofloxacina 100% (n: 21), cotrimoxazol 100% (n: 21) y amikacina 19% (n: 4). Se observó 100% de sensibilidad a tigeciclina y ceftazidima/avibactam. CONCLUSIÓN: Este estudio demuestra un valor significativo de la resistencia a colistina en comparación a ceftazidima/avibactam y tigeciclina.

BACKGROUND: There is an increase of carbapenem-resistant Klebsiella pneumoniae (CRKP) infections in the pediatric population and epidemiological data are limited. Aim: To calculate the frequency of CRKP in pediatric patients, to determine the in vitro activity of colistin and to detect the presence of mcr-1 gene in said isolates. METHODS: 220 isolates of K. pneumoniae were studied in a pediatric hospital between January 2018 and December 2019. Antimicrobial susceptibility was determined by microdilution in broth according to guidelines of CLSI and EUCAST. The genes blaKPC, blaNDM, blaIMP, blaVIM, blaOXA-48 and mcr-1 were detected by polymerase chain reaction (PCR). RESULTS: 9.5% (n: 21) of the isolates were characterized as CRKP, where was observed a resistance to colistin of 47.6% (10/21) with values of MIC50 of 2 μg/mL and MIC90 of ≥ 4 μg/mL. In 100% of CRKP strains the blaKPC gene was detected and the mcr-1 gene was not found. The resistance profile to other antimicrobials was as follow: gentamicin 100% (n: 21), trimethoprim/sulfamethoxazole 100% (n: 21), ciprofloxacin 100% (n: 21), amikacin 19% (n: 4). All of the isolates were sensitive to ceftazidime/avibactam and tigecycline. CONCLUSION: This study demonstrates a significant value of resistance to colistin in pediatric patients compared to other last line antimicrobial such as ceftazidime/avibactam and tigecycline.

Costo-efectividad de ceftazidima/avibactam versus colistin + meropenem en el tratamiento de infecciones por enterobacterias resistentes a carbapenémicos en Chile / Cost-effectiveness of ceftazidime/avibactam versus colistin + meropenem for treatment of carbapenemic-resistant enterobacteria infections in Chile

INTRODUCCIÓN: Ceftazidima-avibactam (C/A), ha demostrado reducir las tasas de mortalidad y el riesgo de nefrotoxicidad, comparado con colistin, la terapia convencional. OBJETIVO: Estimar la costo-efectividad de C/A versus colistin + meropenem en el tratamiento de infecciones por Enterobacteriaceae resistentes a carbapenémicos (ERC) en Chile. MATERIAL Y MÉTODOS: Se adaptó un modelo económico tipo árbol de decisión. Se utilizó la perspectiva del pagador público, un horizonte de tiempo de 30 días con extrapolación a la expectativa de vida. La información clínica se derivó de un estudio observacional. Los costos de los medicamentos y de atención corresponden a reportes locales. Los resultados se expresan como razón de costo-efectividad incremental (RCEI) por año de vida ganado (AVG) y por año de vida ajustado por calidad (AVAC) en pesos chilenos y en dólares estadounidenses (US$ 1,00 = $792,2218). RESULTADOS: Se obtuvieron 8,65 y 6,48 AVGs y 6,44 y 4,27 AVACs, para C/A y colistin + meropenem, respectivamente. La RCEI estimada de C/A fue $940.488 (US$1.187,2) por AVG y $938.715 (US$1.184,9) por AVAC. DISCUSIÓN: Dada la falta de publicaciones o evidencia, el modelo se basa en un estudio observacional. C/A reduciría la proporción de muertes e incrementaría los AVG y los AVAC, resultando en una alternativa costo-efectiva versus colistin + meropenem para ERC.

BACKGROUND: Ceftazidime-avibactam (C/A), has shown reduction in mortality rates and risk of nephrotoxicity, compared to colistin, conventional therapy. AIM: To estimate the cost-effectiveness of C/A versus colistin + meropenem in the treatment of infections due to carbapenem-resistant Enterobacteriaceae (CRE) in Chile. METHODS: An economic decision tree type model was adapted. The perspective of the public payer was used with a time horizon of 30 days and extrapolation to life expectancy. The clinical information was derived from an observational study. Medication and care costs correspond to local reports. The results are expressed as incremental cost-effectiveness ratio (ICER) per life year gained (LYG) and per quality adjusted life year (QALY) in Chilean pesos and US dollars (US$ 1.00 = $792.2218). RESULTS: 8.65 and 6.48 LYGs and 6.44 and 4.27 QALYs were obtained, for C/A and colistin + meropenem, respectively. The estimated ICER for C/A was $940,488 (US$1,187.2) per AVG and $938,715 (US$1,184.9) per QALY. DISCUSSION: Given the lack of publications or evidence, the model is based on an observational study. C/A would reduce the death rate and increase LYGs and QALYs, resulting in a cost-effective alternative vs. colistin + meropenem for CRE.

Rational use of Polymyxins against multi-drug resistant Gram-Negative bacteria

@#The current strategy in treating multi-drug resistant gram-negative bacterial (MDR-GNB) infections is salvage therapy by using polymyxins. However, the beginning emergence of polymyxin resistance should enforce strict antimicrobial stewardship programs to preserve polymyxin efficacy. Knowledge of structural characteristics, pharmacodynamic, and pharmacokinetic profiles of polymyxins, as well as consideration of efficacy, safety, suitability, and cost, will help in the choice of the appropriate polymyxin for therapy. Polymyxin B is the recommended polymyxin for systemic use, while colistin is recommended for lower urinary tract infections, intraventricular, and intrathecal use. Either polymyxin can be used for hospital-acquired and ventilator-associated pneumonia. Combination therapy over monotherapy remains to be advantageous due to synergism and decreased resistance development. The choice of the second drug to be used should be based on full susceptibility, or if unavailable, a drug with the least minimum inhibitory concentration relative to the breakpoint set by the Clinical and Laboratory Standards Institute. Using the mnemonic ESCAPE can also guide physicians in their polymyxin prescription process: (1) Checking if the pathogen is Extensively resistant or multi-drug resistant; (2) checking the patient’s clinical status if compatible with Significant infection; (3) using Combination therapy; (4) ensuring Adequate dosing; (5) Proper preparation and administration of drug; and (6) keeping an Eye for response and adverse effects.

Colistina en el tratamiento de infecciones por pseudomonas aeruginosa y acinetobacter baumannii extensivamente resistentes (XDR) en un hospital de tercer nivel / Colistin-based treatment for extensively drug resistant (XDR) Pseudomonas aeruginosa and Acinetobacter baumannii infection at a third level hospital

Resumen Objetivo: Describir la respuesta clínica y mortalidad general de Colistina en infecciones por Pseudomonas XDR y Acinetobacter XDR en el Hospital Nacional Arzobispo Loayza in Lima, Peru. Métodos: Estudio observacional, descriptivo y retrospectivo. Se incluyeron los registros de pacientes > 18 años, desde junio del 2014 a junio del 2016, que tuvieron infección por Pseudomonas XDR o Acinetobacter XDR confirmada por cultivo, y que recibieron colistina. Se realizó análisis univariado de las características generales de los pacientes; un análisis bivariado con test de Chi2 , t-student o ANOVA según corresponda, y además se describió los factores asociados a mortalidad. Resultados. Se incluyeron 56 registros de pacientes, la mediana de la edad fue 46,5 [31,5 a 63,5]. El 48,2% tuvo un cultivo positivo para Pseudomonas XDR y el 51,8% para Acinetobacter XDR. La respuesta clínica favorable fue 85,7% a los 15 días y de 78,6% a los 30 días. La mortalidad intrahospitalaria a los 30 días fue 21,4%, la mortalidad en UCI fue de 30,8% y la nefrotoxicidad fue de 5,4%. Conclusiones. Colistina combinada con otro antimicrobiano tuvo una respuesta clínica favorable en infección por Pseudomonas XDR o Acinetobacter XDR.

Abstract Objective: To describe the clinical response and overall mortality of Colistin in infections by Pseudomonas XDR and Acinetobacter XDR at the Hospital Nacional Arzobispo Loayza in Lima, Peru. Methods: Observational, descriptive, retrospective study. Records of all patients > 18 years old, from June 2014 to June 2016, who had infection by Pseudomonas XDR or Acinetobacter XDR confirmed by culture, and who received colistin, were included. A univariate analysis of the general characteristics of the patients was performed; a bivariate analysis with a Chi2, t-student or ANOVA test as appropriate, and the factors associated with mortality were also determined. Results: 56 patient records were included; the median age was 46,5 [31,5 to 63,5]. The Culture was positive for Pseudomonas XDR in 48,2% and for Acinetobacter XDR in 51,8%. The favorable clinical response was 85,7% at 15 days and 78,6% at 30 days. In-hospital mortality at 30 days was 21,4%, ICU mortality was 30,8% and nephrotoxicity was 5,4%. Conclusions: Colistin combined with another antimicrobial had a favorable clinical response in infection with Pseudomonas XDR and Acinetobacter XDR.

Resistencia a la colistina en cepas de Klebsiella pneumoniae multidrogorresistente del período 2015-2018 en un instituto materno perinatal de Lima, Perú / Colistin resistance in multidrug-resistant Klebsiella pneumoniae strains at a perinatal maternal institute in Lima, Peru, 2015-2018

RESUMEN El objetivo del estudio fue evaluar los niveles y mecanismos de resistencia a la colistina y a los carbapenémicos en cepas de Klebsiella pneumoniae multidrogorresistente aisladas durante el periodo 2015-2018 en el Instituto Materno Perinatal de Lima. Se analizó la sensibilidad mediante difusión en disco y microdilución. La presencia de genes de resistencia a los carbapenémicos y a la colistina se determinó por reacción en cadena de la polimerasa (PCR, por sus siglas en inglés) y se la relacionó con la clonalidad. Se analizaron 36 cepas de K. pneumoniae, cinco (13,8%) fueron resistentes a la colistina, pertenecían a diferentes grupos clonales. Se encontraron dos cepas con carbapenemasas (bla KPC y bla NDM) y no se detectaron genes plasmídicos para la colistina. Los niveles de resistencia al resto de antimicrobianos testados fueron elevados, a excepción de amikacina (13,9%). Los resultados destacan la presencia de cepas resistentes a la colistina (33,3% en 2018), situación preocupante por ser esta parte de las últimas alternativas de tratamiento para las infecciones causadas por patógenos multirresistentes.

ABSTRACT The objective of this study was to evaluate the presence of colistin- and carbapenemic-resistant genes in multidrug-resistant Klebsiella pneumoniae strains isolated at the Instituto Materno Perinatal de Lima (2015-2018). Susceptibility levels were analyzed by disk diffusion and microdilution. The presence of colistin- and carbapenemic-resistant genes was determined by polymerase chain reaction (PCR) and was related to clonality. A total of 36 K. pneumoniae strains were analyzed, 5 (13.8%) were resistant to colistin and belonged to different clonal groups. Only 2 strains were found with carbapenemases (bla KPC and bla NDM), and no colistin plasmid genes were detected. High resistance levels to the other tested antimicrobials were observed, except for amikacin (13.9%). The results highlight the presence of colistin-resistant strains (33.3% in 2018), a worrying situation as they are part of the latest treatment alternatives for infections caused by multiresistant pathogens.

Enterobacterales productores de betalactamasas de espectro extendido portadores del gen mcr-1 en Lima, Perú / Extended-spectrum beta-lactamase-producing enterobacterales carrying the mcr-1 gene in Lima, Peru

RESUMEN Se analizó la presencia del gen mcr-1 en 165 enterobacterales productores de betalactamasas de espectro extendido (EP-BLEE) recuperados en 2017 de sangre (40), orina (57), secreciones respiratorias bajas (12) e hisopados rectales (56) de pacientes hospitalizados en el Instituto Nacional de Enfermedades Neoplásicas (Perú). La identificación y la susceptibilidad antimicrobiana se determinaron por el sistema automatizado Phoenix M50; la resistencia a colistina por Colistin Agar-Spot (CAS); la detección de mrc-1 por el método fenotípico de predifusión de colistina e inhibición con EDTA (CPD-E) y por reacción en cadena de la polimerasa (PCR, por sus siglas en inglés). De los 165 EP-BLEE 25 fueron positivos para mcr-1 por el método CPD-E y se confirmó por PCR. Por el método CAS, 20/165 fueron resistentes a colistina. Además, mostraron resistencia a las fluoroquinolonas y a la gentamicina, y permanecieron sensibles a la amikacina; dos aislamientos presentaron metalocarbapenemasas. La obtención de datos sobre la resistencia a antimicrobianos considerados de última línea (colistina) es crucial para establecer medidas para su control.

ABSTRACT We analyzed the presence of the mcr-1 gene in 165 extended-spectrum beta-lactamase-producing enterobacterales (ESBL-PE) obtained during 2017, from blood (40), urine (57), lower respiratory secretions (12) and rectal swabs (56) of patients hospitalized in the Instituto Nacional de Enfermedades Neoplásicas (Peru). Antimicrobial identification and susceptibility were determined by the Phoenix M50 automated system; colistin resistance by Colistin Agar-Spot (CAS); mrc-1 detection by colistin pre-diffusion and inhibition with EDTA test (CPD-E) and by polymerase chain reaction (PCR). We found that from the 165 ESBL-PE, 25 were positive for mcr-1 by the CPD-E method and confirmed by PCR. Colistin resistance was found in 20/165 by using the CAS method. Additionally, they showed resistance to fluoroquinolones and gentamicin, while remaining sensitive to amikacin; two isolates presented metallo-carbapenemases. Obtaining data on resistance to last-line antimicrobials (colistin) is crucial to establish measures for its control.

Gérmenes aislados en pacientes ingresados en la terapia intensiva del Hospital Clínico Quirúrgico Provincial Dr. Joaquín Albarrán / Germs isolated from intensive care patients at Dr. Joaquín Albarrán Provincial Clinical Surgical Hospital

Introducción: Las infecciones asociadas a los cuidados sanitarios en los servicios de atención al paciente crítico se asocian a un alto riesgo de muerte y costos significativos. Objetivo: Identificar los gérmenes más frecuentes en los cultivos y su resistencia a los antimicrobianos en la terapia intensiva del Hospital Clínico Quirúrgico Provincial Dr. Joaquín Albarrán. Métodos: Se realizó un estudio descriptivo, retrospectivo, en la terapia intensiva del Hospital Clínico Quirúrgico Provincial Dr. Joaquín Albarrán, de enero del 2015 a diciembre del 2018, el universo estuvo constituido por 1847 cultivos realizados seleccionándose 654 en los que se obtuvo crecimiento; para el análisis estadístico se utilizó el SPSS 22.0. Resultados: De los gérmenes aislados, la Klebsiella spp fue la más frecuente (31 por ciento), seguida del Staphylococcus spp (24,5 por ciento) y de la E. coli (9,8 por ciento). En los esputos se mantuvo la Klebsiella spp (45,1 por ciento), en los hemocultivos el Staphylococcus spp (53,6 por ciento) y en los urocultivos la Candida (41,1 por ciento), seguida de la E. coli (27 por ciento). De los antimicrobianos usados en terapia para tratar la Klebsiella spp, la E. coli, el Acinetobacter y la pseudomona spp, el más recomendado es la colistina (0-25 por ciento de resistencia) y para el Staphylococcus spp, la vancomicina (1,8 por ciento). Conclusiones: Los gérmenes Gram negativos siguen siendo los más frecuentemente aislados en los cultivos de los pacientes hospitalizados en terapia, con un alto nivel de resistencia para la mayoría de los antibióticos(AU)

Introduction: Infections related to critical care settings are associated to high death risk and significant costs. Objective: Identify the germs most commonly found in cultures and their resistance to antimicrobials in the intensive care service of Dr. Joaquín Albarrán Provincial Clinical Surgical Hospital. Methods: A retrospective descriptive study was conducted at the intensive care service of Dr. Joaquín Albarrán Provincial Clinical Surgical Hospital from January 2015 to December 2018. The study universe was 1 847 cultures, from which 654 were selected in which growth was obtained. Data were processed with the statistical software SPPS 22.0. Results: Of the germs isolated, Klebsiella spp. were the most common (31 percent, followed by Staphylococcus spp. (24.5 percent) and E. coli (9.8 percent). Klebsiella spp. were frequent in sputum cultures (45.1 percent), Staphylococcus spp. in blood cultures (53.6 percent) and Candida in urine cultures (41.1 percent), followed by E. coli (27 percent). Among the antimicrobials used to treat Klebsiella spp., E. coli, Acinetobacter and Pseudomonas spp., the most recommended is colistin (0-25 percent resistance) and vancomycin for Staphylococcus spp. (1.8 percent). Conclusions: Gram-negative germs continue to be the most commonly isolated in cultures from intensive care patients, with a high level of resistance to most antibiotics(AU)

Detection of the mcr-1 gene in Enteropathogenic Escherichia coli (EPEC) and Shigatoxigenic E. coli (STEC) strains isolated from broilers / Detecção do gene mcr-1 em estirpes de Escherichia coli Enteropatogênicas (EPEC) e Shigatoxigênicas (STEC) isoladas de frangos de corte

Enteropathogenic Escherichia coli (EPEC) and Shigatoxigenic E. coli (STEC) strains are among the major pathotypes found in poultry and their products, which are capable of causing human enteric infections. Colistin has been claimed the drug of choice against diseases caused by multidrug-resistant Gram-negative bacteria (MDRGN) in humans. The mcr-1 gene was the first plasmidial gene that has been described to be responsible for colistin resistance and has also been detected in birds and poultry products. Our study aimed to detect the mcr-1 gene in enteropathogenic strains of E. coli in order to evaluate the resistance to colistin in broilers. The material was obtained from 240 cloacal samples and 60 broiler carcasses. The strains were isolated by the conventional bacteriological method and by the virulence genes, which characterize the enteropathogenic strains and resistance, and the samples were detected by polymerase chain reaction (PCR). Of the 213 isolated strains of E. coli, 57 (26.76%) were characterized as atypical EPEC and 35 (16.43%) as STEC. The mcr-1 gene was found in 3.5% (2/57) of the EPEC strains and 5.7% (2/35) of the STEC strains. In this study, it was possible to confirm that the mcr-1 resistance gene is already circulating in the broiler flocks studied and may be associated with the pathogenic strains.(AU)

Escherichia coli Enteropatogênica (EPEC) e Shigatoxigênica (STEC) estão entres os principais patotipos encontrados em aves e produtos avícolas que são capazes de causar doença entérica no homem. A colistina tem sido preconizada como droga de escolha para o tratamento de doenças causadas por bactérias Gram-negativas multirresistentes em humanos. O gene mcr-1 foi o primeiro gene plasmidial a ser descrito como responsável pela resistência a colistina e tem sido descrito em aves e produtos avícolas. Este estudo tem como objetivo a detecção do gene mcr-1 em estirpes de E. coli enteropatogênicas a fim de avaliar a resistência a colistina em frangos de corte. O material foi obtido a partir de 240 amostras cloacais e 60 carcaças de frango de corte. As estirpes foram isoladas pelo método bacteriológico convencional e os genes de virulência, que caracterizam as estirpes enteropatogênicas, e resistência foram detectados pela reação em cadeia pela polimerase (PCR). Das 213 estirpes de E. coli isoladas, 57 (26,76%) foram caracterizadas como EPEC atípica e 35 (16,43%) como STEC. O gene mcr-1 foi encontrado em 3,5% (2/57) das estirpes EPEC e 5,7% (2/35) das estirpes STEC. Neste estudo foi possível confirmar que o gene de resistência mcr-1 já está em circulação nos lotes de frango de corte estudados e pode estar associado às estirpes patogênicas.(AU)

Zigomicosis y síndrome hemofagocítico en un paciente inmunocompetente: informe de caso / Zygomycosis and hemophagocytic lymphohistiocytosis in an immunocompetent patient: a case report

Introducción: la zigomicosis es una infección fúngica poco frecuente, con alta tasa de mortalidad y de mal pronóstico. Afecta principalmente a pacientes inmunocomprometidos. La asociación con el síndrome hemofagocítico es extremadamente inusual, más aún en pacientes inmunocompetentes, con pocos ejemplos registrados en la literatura. Caso clínico: se presenta el caso de un paciente masculino inmunocompetente de 40 años con diagnóstico de mucormicosis y síndrome hemofagocítico que evoluciona desfavorablemente, con fallo multiorgánico, a pesar de los esfuerzos médicos. Conclusión: la asociación de mucormicosis con síndrome hemofagocítico en un paciente inmunocompetente es extremadamente rara; existen pocos casos informados en Latinoamérica. Debemos tener presente esta asociación, ya que requiere un tratamiento agresivo y soporte vital avanzado. (AU)

Introduction: zygomycosis is a rare fungal infection that carries with high mortality rates. This poor prognosis, rapidly progressive infection mainly affects immunocompromised patients. The association with hemophagocytic lymphohistiocytosis is extremely unusual, even more in immunocompetent patients, with few cases reported. Case: we present the case of an immunocompetent male patient who was diagnosed with zygomycosis and hemophagocytic lymphohistiocytosis. Despite medical efforts he developed multiorganic failure. Conclusion: the association of mucormycosis with hemophagocytic lymphohistiocytosis in an immunocompetent patient is exceptional with few cases reported in Latin America. We must always suspect this association considering they require aggressive treatment and advanced life support. (AU)

Evaluación de la elución de sensidiscos para la determinación de susceptibilidad a colistín en bacilos gramnegativos multi-resistentes / Evaluation of sensi-disk elution for colistin susceptibility determination in multidrug resistant gramnegative bacilli

Resumen Utilizando cepas clínicas de bacilos gramnegativos multi-resistentes (MDR), comparamos las CIM obtenidas de la microdilución en caldo, el método de referencia y el método de elución de sensidiscos. Encontramos que, con la excepción de A. baumannii, los resultados fueron muy similares. El método de elución de sensidiscos podría ser una buena alternativa y confiable para la determinación de la resistencia a colistín.

Abstract Using clinical strains of multidrug resistant (MDR) Gram negative bacilli, we compared MICs obtained from both broth microdilution, the reference method, and sensi-disk elution method. We found that, with A. baumannii exception, results were very similar. Sensi-disk elution method could be a good and reliable alternative for colistin resistance determination.

Evaluation of Synergistic Effect of Combined Treatment with Linalool and Colistin on Multidrug-Resistant Acinetobacter baumannii to Expand Candidate for Therapeutic Option / 대한임상미생물학회지

BACKGROUND: Acinetobacter baumannii infection is a significant health problem worldwide due to increased drug resistance. The limited antimicrobial alternatives for the treatment of severe infections by multidrug-resistant A. baumannii (MDRAB) make the search for other therapeutic options more urgent. Linalool, the major oil compound in Coriandrum sativum, was recently found to have high antibacterial activity against A. baumannii. The purpose of this study was to investigate the synergistic effect of linalool and colistin combinations against MDRAB and extensively drug-resistant A. baumannii (XDRAB).METHODS: A total of 51 strains of A. baumannii clinical isolates, consisting of 10 MDRAB and 41 XDRAB were tested. We determined the minimum inhibitory concentration (MIC) of linalool for the test strains using the broth microdilution method and searched for interactions using the time-kill assay.RESULTS: The time-kill assay showed that the linalool and colistin combination displayed a high rate of synergy (92.1%) (by synergy criteria 2), low rate of indifference (7.8%), and a high rate of bactericidal activity (74.5%) in the 51 clinical isolates of A. baumannii. The synergy rates for the linalool and colistin combination against MDRAB and XDRAB were 96% and 92.1%, respectively. No antagonism was observed for the linalool and colistin combination.CONCLUSION: The combination of linalool and colistin showed a high synergy rate, which may be beneficial for controlling MDRAB infections. Therefore, this combination is a good candidate for in vivo studies to assess its efficacy in the treatment of MDRAB infections.

Mucosal bacterial vaccines in clinical practice - a novel approach to an old problem?

SUMMARY OBJECTIVES To evaluate the efficacy of mucosal bacterial vaccines (MBV) in reducing the number of exacerbations in patients with chronic respiratory disease. METHODS A prospective cohort study of patients followed at the Pneumology Unit of the University and Hospital Centre of Coimbra, with frequent infectious exacerbations (3 or more) despite the best therapeutic strategies employed. MBV was used as additional therapy. The number of exacerbations 1 year before therapy and 1 year after it were analyzed. RESULTS A sample of 11 individuals, 45.5% male, mean age 62.5 years. Eight patients had non-cystic fibrosis bronchiectasis, 2 COPD (1 on long-term oxygen therapy), and 1 patient with Mounier Kuhn's syndrome. Three patients were on azithromycin, 1 on inhaled colistin, and 2 on inhaled tobramycin. Out of the 11 patients, one presented complication (fever), which led to a suspension of therapy (excluded from results). Of the 10 patients who completed treatment, 5 had bacterial colonization and were submitted to a custom vaccine. The remaining 6 completed the standard composition. The average of infectious exacerbations in the previous year was 4.3 (0.7 with hospitalization). In the year after therapy, the mean number was 1.5 (0.5 with hospitalization). CONCLUSION The results obtained in this study favor the use of bacterial immunostimulation to reduce the frequency of RRIs in patients with chronic respiratory disease.

RESUMO OBJETIVO Avaliar a eficácia de vacinas bacterianas de mucosa (MBV) na redução do número de exacerbações de pacientes com doença respiratória crônica. MÉTODOS Um estudo de coorte prospectivo incluindo pacientes da Unidade de Pneumologia da Universidade e Centro Hospitalar de Coimbra, com exacerbações infecciosas frequentes (3 ou mais), apesar do uso das melhores estratégias terapêuticas. MBVs foram usadas como terapia adicional. O número de exacerbações 1 ano antes da terapia e 1 ano após ela foram analisados. RESULTADOS Amostra incluiu 11 indivíduos, 45,5% do sexo masculino, com média de idade de 62,5 anos. Oito pacientes apresentaram bronquiectasia não relacionada à fibrose cística, 2 DPOC (1 em oxigenoterapia prolongada) e 1 paciente com síndrome de Mounier-Kuhn. Três pacientes estavam sendo medicados com azitromicina, 1 com colistina inalada e 2 com tobramicina inalada. Dos 11 pacientes, um apresentou complicação (febre), o que levou à suspensão da terapia (excluído dos resultados). Dos 10 pacientes que completaram o tratamento, 5 apresentaram colonização bacteriana e receberam uma vacina personalizada. Os 6 restantes foram tratados com a composição padrão. A média de exacerbações infecciosas no ano anterior foi de 4,3 (0,7 com hospitalização). No ano após a terapia, o número médio foi de 1,5 (0,5 com hospitalização). CONCLUSÃO Os resultados obtidos neste estudo favorecem o uso de imunoestimulação bacteriana para reduzir a frequência de infecções respiratórias recorrentes em pacientes com doença respiratória crônica.

Effectiveness and adverse effects of Intravenous Colistin In Neonates with Multi-Drug Resistant Gram-Negative Bacterial Infections

Background@#The global burden of multi-drug resistant gram-negative bacterial (MDR-GNB) infections has been increasing. Neonates are at a particularly high-risk and there is limited treatment option. The use of colistin has been re-introduced for this population. However, data on its use in neonates is scarce. @*Objectives@#To determine the effectiveness and adverse effects of intravenous colistin in neonates with multidrug-resistant gram-negative infections. @*Design@#This is a retrospective cohort study of the clinical profile and outcome of neonates with MDR-GNB infections given colistin for a minimum of 3 days conducted from April 2015 to April 2019. @*Results@#A total of 175 pediatric patients had MDR-GNB infections. 75 (43%) neonates met the inclusion criteri a and received intravenous colistin. Of the 75 patients with MDRGNB infections- that included sepsis, pneumonia, urinary tract infection and abscess, 37 (49.3%) were alive and 38 (50.7%) patients died. Nephrotoxicity was seen in 4% if patients and 2.6% patients had hypersensitivity reaction. MDROs isolated were Acinetobacter baumanii, Klebsiella pneumoniae and Pseudomonas aeruginosa. @*Conclusions@#Intravenous colistin is 50% effective and is relatively safe to use in neonates.

Perfil fenotípico de resistência à colistina e tigeciclina em um hospital público no Brasil / Phenotypical profile of colistin and tigecycline resistance in a public hospital in Brazil / Perfil fenotípico de resistencia a la colistina y tigeciclina en un hospital público de Brasil

Justificativa e objetivos: Infecções Relacionadas à Assistência à Saúde (IRAS) causadas por bacilos Gram negativos multirresistentes (BGN-MDR) são consideradas um problema de saúde pública e um impacto nas taxas de mortalidade nas Unidades de Terapia Intensiva (UTI). O objetivo deste estudo foi verificar o perfil fenotípico de resistência à colistina e à tigeciclina, consideradas como último recurso terapêutico aos BGN-MDR. Métodos: Os dados foram coletados nas fichas de busca ativa do serviço de controle de infecções e prontuários médicos de pacientes internados em duas UTIs de um hospital público de Joinville, entre janeiro de 2016 e junho de 2017. Resultados: Ocorreram 256 IRAS por BGN, acometendo principalmente o gênero masculino (62%), com mediana de idade de 65 anos. Entre os BGN, 37% expressaram MDR; sendo as espécies mais frequentes: Klebsiella pneumoniae e (47%), Acinetobacter baumannii (23%) e Stenotrophomonas maltophilia (11%). A resistência de BGN-MDR à colistina e tigeciclina foi de 5% e de 12%, respectivamente; 5% dos isolados foram resistentes aos dois antibióticos. A taxa de óbito entre os pacientes com IRAS por BGN-MDR resistentes à colistina foi mais alta (60%) que aquelas à tigeciclina (45%). Conclusão: K. pneumoniae e A. baumannii produtores de carbapenemases, resistentes a colistina e tigeciclina prevaleceram entre os BGN-MDR, e estiveram associadas a maioria dos óbitos. Essas observações, junto com o alto uso de carbapenêmicos na terapia empírica, mostra a necessidade do uso racional de antimicrobianos.(AU)

Background and objectives: Healthcare-associated Infections (HAIs) caused by multidrug-resistant Gram-negative bacilli (GNB-MDR) are considered a public health problem and have an impact on mortality rates in Intensive Care Units (ICU). The aim of this study was to verify the phenotypic profile of resistance to colistin and tigecycline, considered as the last antimicrobial choice to treat BGNMDR infections. Methods: Data were collected on the active search records of the infection control service and medical records of patients admitted to two ICUs at a public hospital in Joinville between January 2016 and June 2017. Results: There were 256 HAIs caused by GNB, mainly affecting males (62%), with a median age of 65 years. Among GNBs, 37% expressed MDR; the most frequent species were: Klebsiella pneumoniae (47%), Acinetobacter baumannii (23%) and Stenotrophomonas maltophilia (11%). The resistance of GNB-MDR to colistin and tigecycline was 5% and 12%, respectively; 5% of the isolates were resistant to both antibiotics. The death rate among patients with HAIs caused by colistin-resistant GNB-MDR was higher (60%) than those to tigecycline (45%). Conclusion: Carbapenemase-producing K. pneumoniae and A. baumannii, resistant to colistin and tigecycline, prevailed among GNB-MDRs, and were associated with most deaths. These observations, coupled with the high use of carbapenems in empirical therapy, show the need for rational use of antimicrobials.(AU)

Justificación y objetivos: Las Infección nosocomial (IHs) causadas por bacilos Gram negativos multirresistentes (BGN-MDR) se consideran un problema de salud pública y un impacto en las tasas de mortalidad en las Unidades de Terapia Intensiva (UTI). El objetivo de este estudio fue verificar el perfil fenotípico de resistencia a la colistina ya la tigeciclina, consideradas como último recurso terapéutico a los BGN-MDR. Métodos: Los datos fueron recolectados en las fichas de búsqueda activa del servicio de control de infecciones y prontuarios médicos de pacientes internados en dos UTIs de un hospital público de Joinville, entre enero de 2016 y junio de 2017. Resultados: Ocurrieron 256 IHs por BGN, que afectan principalmente al género masculino (62%), con mediana de edad de 65 años. Entre los BGN, el 37% expresó MDR; siendo las especies más frecuentes: Klebsiella pneumoniae (47%), Acinetobacter baumannii (23%) y Stenotrophomonas maltophilia (11%). La resistencia de BGN-MDR a la colistina y tigeciclina fue del 5% y del 12%, respectivamente; 5% de los aislados fueron resistentes a los dos antibióticos. La tasa de muerte entre los pacientes con IH causadas por los BGN-MDR resistentes la colistina fue más alta (60%) que aquellas a tigeciclina (45%). Conclusión: K. pneumoniae y A. baumannii productoras de carbapenemases, resistentes la colistina y la tigeciclina, fueron más frecuentes entre los BGN-MDR y su asociación estuvo presente en la mayoría de las muertes. Estas observaciones, junto con el alto uso de carbapenems en la terapia empírica, muestran la necesidad de un uso racional de los antimicrobianos.(AU)

Escenario actual de la resistencia a la colistina mediada por plásmidos en América Latina / Current scenario of plasmid-mediated colistin resistance in Latin America

Colistin resistance can occur by chromosomal mutations and by acquisition of plasmid-carrying determinants, mainly mcr-1. In the recent years, we have observed the out-burst of this resistance gene in our region. Due to the risk of the rapid dissemination of mcr-1, this finding has worried and alerted different actors from the health field and has become one of the most prolific topics. Our review compiles available reports of well-documented mcr-1-positive strains of Enterobacteriaceae, obtained from different samples in Argentina and other countries of Latin America. Furthermore, it addresses the association of mcr-1 with ESBL resistance markers and outlines the platforms involved in their dissemination.

La resistencia a la colistina puede ocurrir por mutaciones cromosómicas o por la adquisición de determinantes localizados en plásmidos, el principal es mcr-1. En los últimos años hemos observado la explosiva aparición de este gen de resistencia en nuestra región. Debido al riesgo que implica la rápida diseminación de mcr-1, este hallazgo ha preocupado y alertado a los diferentes actores del área de la salud, y se ha convertido en uno de los temas de investigación más importantes. La presente revisión compila los informes de aislamientos portadores de mcr-1 debidamente documentados en Enterobacteriaceae, obtenidos de diferentes muestras en Argentina y otros países de América Latina. Además, aborda la asociación de mcr-1 con otros marcadores de resistencia, como las BLEE, y describe las plataformas involucradas en su diseminación.

Intravenous Colistin Therapy for Multidrug-Resistant Gram-Negative Bacterial Infections in Major Burn Injuries

PURPOSE: The aim of this study was to investigate the characteristics of Acute Kidney Injury Network (AKIN)-defined nephrotoxicity in patients undergoing intravenous colistimethate sodium (CMS) therapy for major burns. METHODS: This retrospective study included burn patients who received more than 48 h of intravenous CMS between September 2009 and December 2015. Data collection was performed using the institution's electronic medical record system. Patients assigned to the developed nephrotoxic group experienced aggravation of current AKIN stage during CMS treatment; those assigned to the non-nephrotoxic group experienced no change in current or exhibited improved AKIN stage during CMS therapy. RESULTS: A total of 306 patients were included in this study. All patients were grouped according to AKIN stage: AKIN 0 (n=152); AKIN 1 (n=6); AKIN 2 (n=9); AKIN 3 (n=139). The baseline creatinine (Cr) level was 0.73 mg/dL. The incidence of nephrotoxicity was 50.3% according to AKIN stage; overall mortality was 45.8%. The non-nephrotoxic group consisted of 127 (74.7%) patients and 43 (25.3%) were in the developed nephrotoxic group. In patients requiring continuous renal replacement therapy (CRRT), baseline Cr level was 0.83 mg/dL, pre-CMS Cr level was 1.17 mg/dL, and post-CMS Cr level was 1.34 mg/dL. CONCLUSION: CMS can be administered without signs of nephrotoxicity for a certain period (approximately 1 week), it can be used relatively safely for 2 weeks. Application of CMS is a reasonable option for treating infections caused by multi-drug resistant gram-negative bacteria in patients with major burns. The caution should be exercised nevertheless.

Non-clonal occurrence of pmrB mutations associated with polymyxin resistance in carbapenem-resistant Klebsiella pneumoniae in Brazil

BACKGROUND Polymyxins are currently used as a "last-line" treatment for multidrug-resistant Gram-negative infections. OBJECTIVES To identify the major mechanisms of resistance to polymyxin and compare the genetic similarity between multi-drug resistant Klebsiella pneumoniae strains recovered from inpatients of public hospitals in the Mid-West of Brazil. METHODS 97 carbapenems non-susceptible K. pneumoniae were studied. β-lactamases (bla OXA-48, bla KPC, bla NDM, bla CTX-M, bla SHV, bla TEM, bla IMP, bla VIM) and mcr-1 to mcr-5 genes were investigated by polymerase chain reaction (PCR). Mutations in chromosomal genes (pmrA, pmrB, phoP, phoQ, and mgrB) were screened by PCR and DNA sequencing. Clonal relatedness was established by using pulsed-field gel electrophoresis and multilocus sequence typing. FINDINGS K. pneumoniae isolates harbored bla KPC (93.3%), bla SHV (86.6%), bla TEM (80.0%), bla CTX-M (60%) genes. Of 15 K. pneumoniae resistant to polymyxin B the authors identified deleterious mutations in pmrB gene, mainly in T157P. None K. pneumoniae presented mcr gene variants. Genetic polymorphism analyses revealed 12 different pulsotypes. MAIN CONCLUSIONS Deleterious mutations in pmrB gene is the main chromosomal target for induction of polymyxin resistance in carbapenem-resistant K. pneumoniae in public hospitals in the Mid-West of Brazil.

Relação ancestral e pan-resistoma plasmidial de Escherichia coli produtora de CTX-M-8 e MCR-1 na interface humana, animal e ambiental / Ancestral relationship and plasmid pan-resistome of CTX-M-8- and MCR-1-producing Escherichia coli in human-animal-environmental interface

Linhagens de Escherichia coli produtoras de ß-lactamase de espectro estendido (ESßL) do tipo CTX-M são endêmicas no Brasil, sendo prevalentes em casos de infecções hospitalares e ambulatoriais. Atualmente, cepas produtoras de CTX-M têm sido recuperadas de ambientes urbanos, animais de companhia ou de produção e de alimentos de origem animal, inclusive afetando o agronegócio, o que aponta uma possível rota de disseminação em diferentes ecossistemas. Recentemente, nesta espécie, foi descoberto um novo gene, chamado de mcr-1, que confere resistência transferível à colistina, um dos últimos antibióticos eficazes para o tratamento de infecções causadas por bactérias produtoras de ESBL e carbapenemases. Deste modo, o presente estudo tem como objetivo elucidar os aspectos sobre a caracterização e a relação de plasmídeos que carregam genes do tipo blaCTX-M-8 e mcr- 1 em cepas de E. coli isoladas de seres humanos, animais, ambiente aquático e alimentos, no Brasil. Neste estudo são apresentados os resultados da análise plasmidial de 25 cepas de E. coli, das quais nove apresentaram o genótipo blaCTX-M-8/IncI1, 11 apresentaram o genótipo mcr-1/IncX4 e cinco apresentaram ambos os genótipos blaCTX-M-8/IncI1 e mcr-1/IncX4. Dos resultados, podemos observar que plasmídeos IncI1 (blaCTX-M-8) e IncX4 (mcr-1) estão circulando no Brasil desde o ano de 2009 entre diferentes clones (STs) de E. coli e em diferentes ambientes e hospedeiros. Os plasmídeos IncI1 foram conjugativos e pertencentes ao ST113, exceto o plasmídeo recuperado de um isolado humano, que foi pertencente ao ST131. Os plasmídeos IncI1 apresentaram sua arquitetura conservada, com a presença de genes de replicação, transferência e estabilidade. A partir do alinhamento, os plasmídeos IncI1 apresentaram 94-99% de similaridade genética entre eles. Dentre os plasmídeos IncX4, independente da fonte de isolamento, todos permaneceram com sua arquitetura altamente conservada. Entretanto, apenas dois plasmídeos (um encontrado em uma cepa de animal e outro encontrado em uma cepa de ambiente aquático) apresentaram uma IS1294, truncando o gene de mobilização. Na análise comparativa, todos os plasmídeos IncX4 apresentaram similaridade genética de 95-99,9% entre eles. No alinhamento de plasmídeos IncX4 brasileiros contra plasmídeos de outras regiões geográficas, foi observada similaridade genética > 99,9%, o que confirma a estabilidade e conservação desses plasmídeos. Neste estudo foram reportados dados inéditos da primeira identificação do gene mcr-1 em diferentes ecossistemas no Brasil, assim como a nova variante mcr-5.3. A análise filogenética dos plasmídeos IncI1 e IncX4, destacam que ambos compartilham uma arquitetura conservada, e a evolução é atribuída à aquisição de genes de resistência. Adicionalmente, um novo vetor de disseminação do gene mcr-1 no Brasil foi identificado - o plasmídeo IncHI2. Os resultados desse estudo demonstram o grave problema da resistência bacteriana dentro do conceito One-health e que, com o avanço de ferramentas moleculares, a identificação e a resolução desse problema poderá estar cada vez mais próxima de ser elucidada

CTX-M-type extended-spectrum-ß-lactamase (ESßL)-producing-Escherichia coli are endemic in Brazil and are prevalent in cases of nosocomial and ambulatory infections. Currently, CTXM-producing strains have been recovered from urban environments, companion/production animals and animal source foods, which indicates a possible route of dissemination in different ecosystems. Recently, in this species, a new gene, called mcr-1, has been discovered, conferring transferable resistance to colistin, one of the last effective antibiotics for the treatment of infections caused by ESBL- and carbapenemases -producing bacteria. Thus, the present study aims to elucidate unknown aspects of the pan-resistome and ancestral relationship of plasmids carrying blaCTX-M-8 and mcr-1 genes in strains of E. coli isolated from humans, animals, aquatic environment and food, in Brazil. In this study, we present results from the plasmidial analysis of 25 E. coli strains, from which nine presented the blaCTX-M-8/IncI1 genotype, 11 presented the mcr-1/IncX4, and five presented both blaCTX-M-8/IncI1 and mcr-1/IncX4 genotypes. Among these results, we can observe that IncI1 (blaCTX-M-8) and IncX4 (mcr-1) plasmids are circulating in Brazil since 2009, between different E. coli clones (STs) and different hosts and environments. IncI1 plasmids were conjugative and assigned to ST113, with exception of a plasmid recovered from a human isolate, which was assigned to ST131. IncI1 plasmids presented conserved architecture, with the presence of genes of replication, transference, and stability. From the alignment analysis, IncI1 plasmids presented 94-99% genetic similarity among them. Among the IncX4 plasmids, regardless the isolation source, their architecture remained highly conserved. However, only two plasmids (one detected in an animal's strain and another detected in an aquatic environment's strain) presented an IS1294, truncating the mobilization gene. In the comparative analysis, all IncX4 plasmids presented 95-99,9% genetic similarity among them. In the alignment of Brazilian IncX4 plasmids against plasmids from other geographic regions, >99.9% genetic similarity was observed, confirming the stability and conservation of these plasmids. In this study, unprecedented data from the first identification of the mcr-1 gene in different ecosystems in Brazil, as well as the new variant, mcr-5.3. Additionally, it was identified a new dissemination vector of the mcr-1 gene in Brazil - the IncHI2 plasmid. Phylogenetic analysis of IncI1and IncX4 plasmids highlight that both share a conserved backbone, and evolution is attributed to the acquisition of clinically relevant antimicrobial resistance genes. The results from this study demonstrate the serious problem of the bacterial resistance within the "One-Health" concept and that, with the advance of molecular tools, identification and resolution of this problem may be increasingly closer to being elucidate