Quinolones resistance in Salmonella spp. isolated from broilers and chickens carcasses under federal inspection / Resistência à quinolonas em Salmonella spp. isoladas de frangos vivos e carcaças sob inspeção federal

We analyzed 77 Salmonella spp. strains, from which 20 were isolated from broilers (cloacal swabs) and 57 from chickens from slaughterhouses under federal inspection. The following serotypes were identified: Salmonella Saint Paul (29), Salmonella Heidelberg (27), Salmonella Anatum (9), Salmonella Cerro (5), Salmonella Senftenberg (5), Salmonella enterica (O: 4,5) (1) and Salmonella enterica (O: 9.12) (1). Fifteen strains (19.5%) were resistant to enrofloxacin, six (7.8%) to ciprofloxacin, and 26 (33.8%) to nalidixic acid in the Disk Diffusion Test. The fifteen enrofloxacin resistant strains were selected for the PCR to detect the genes gyrA, gyrB, parC, and parE, and genetic sequencing to identify mutations in these genes. Five strains (33.3%) had point mutations in the gyrA gene, and one (6.7%) presented a point mutation in the parC gene. None of the 15 strains had mutations in the gyrB and parE genes, and none had more than one mutation in the gyrA gene or the other genes. The presence of point mutations in the strains studied corroborates with the phenotypic resistance observed to nalidixic acid. However, it did not explain the resistance to fluoroquinolones found in the 15 strains. Other mechanisms may be related to the fluoroquinolones resistance, highlighting the need for additional mutation screening.(AU)

Foram analisadas neste estudo 77 estirpes de Salmonella spp., 20 isoladas de frangos vivos (suabes de cloaca) e 57 isoladas de carcaças, provenientes de abatedouros frigoríficos sob Inspeção Federal. Foram identificados os seguintes sorotipos: Salmonella Saint Paul (29), Salmonella Heidelberg (27), Salmonella Anatum (9), Salmonella Cerro (5), Salmonella Senftenberg (5), Salmonella enterica (O: 4,5) (1) e Salmonella enterica (O: 9,12) (1). Do total de estirpes estudadas, 15 (19,5%) se mostraram resistentes à enrofloxacina, seis (7,8%) à ciprofloxacina e 26 (33,8%) ao ácido nalidíxico no Teste de Difusão em Disco. Foram selecionadas as 15 estirpes resistentes à enrofloxacina para a realização da PCR para detecção dos genes gyrA, gyrB, parC e parEe para sequenciamento genético do produto da PCR para identificação de mutações nesses genes. Cinco estirpes (33,3%) apresentaram mutações pontuais no gene gyrA e uma (6,7%) apresentou mutação pontual no gene parC. Nenhuma das 15 estirpes apresentou mutações nos genes gyrB e parE e nenhuma apresentou mais de uma mutação no gene gyrA ou nos outros genes. A existência apenas de mutações pontuais em alguns genes das estirpes analisadas está de acordo com a resistência fenotípica observada ao ácido nalidíxico, mas não explica a resistência às fluoroquinolonas encontrada nas 15 estirpes. Outros mecanismos de resistência podem estar relacionados à resistência encontrada às fluoroquinolonas e estudos adicionais são necessários para investigar sua presença.(AU)

Antibiotic-Resistant Salmonella, isolated from cloacal swab samples from turtles in Guatemala / Salmonella resistente a antibióticos, aislada de muestras de hisopados cloacales en tortugas de Guatemala

Salmonellosis is a relevant public health threat worldwide. Reptiles are commonly involved in human cases. A microbiological survey was conducted from August to October 2018 to isolate Salmonella bacteria and de-termine if they were resistant to regularly used antibiotics in eight species of pet turtles (Kinosternon acutum sp., K. leucostomum, K. scorpioides, Rhinoclemmys areolata sp., R. pulcherrima, Staurotypus salvinii sp., Trachemys scripta and T. venusta) in Guatemala city, San Lucas Sacatepéquez and Antigua Guatemala. Cloacal swabs were taken from 63 turtles and cultivated in the Microbiology Laboratory at the Veterinary Medicine and Animal Hus-bandry Faculty, University of San Carlos of Guatemala, in Guatemala City. Three samples were positive to the presence of Salmonella sp. One of these isolates (from Trachemys scripta) was resistant to gentamicin, penicillin and amikacin, other isolate (from T. scripta) was partially resistant to amoxicilin + clavulanic acid and penicillin, and other (from T. venusta) to penicillin. These findings highlight the need for better biosecurity practices and show the capacity of bacteria to develop survival strategies that involve resistance to harmful substances like antibiotics.

La salmonelosis es una importante enfermedad zoonótica considerada una amenaza a la salud pública a nivel mundial. Los reptiles están comúnmente involucrados en la transmisión animal-humano. Con el objetivo de determinar la presencia de Salmonella y determinar su resistencia a antibióticos de uso común, se realizó un estudio exploratorio en ocho especies de tortugas (Kinosternon acutum sp., K. leucostomum, K. scorpioides, Rhinoclem-mys areolata sp., R. pulcherrima, Staurotypus salvinii sp., Trachemys scripta y T. venusta) en Guatemala y en San Lucas Sacatepéquez. Se tomaron hisopados cloacales de 63 especímenes y se cultivaron en el Laboratorio de Microbiología de la Facultad de Medicina Veterinaria y Zootecnia de la Universidad de San Carlos de Guatemala. Tres muestras fueron positivas a la presencia de Salmonella sp. Uno de los aislados (de Trachemys scripta) fue resistente a gentamicina, penicilina y amikacina, otro aislado (de T. scripta) fue parcialmente resistente a amoxicilina + ácido clavulánico y a penicilina y un tercer aislado (de T. venusta) a penicilina. Estos hallazgos resaltan la necesidad de mejores prácticas de bioseguridad y muestran la capacidad de las bacterias para desarrollar estrategias de sobrevivencia que involucran la resistencia a sustancias que les son nocivas, como los antibióticos.

Salmonelosis invasiva en un hospital de Lima, Perú / Invasive salmonellosis in a hospital in Lima, Peru

RESUMEN El objetivo del estudio fue determinar las características epidemiológicas, clínicas y laboratoriales de los casos de salmonelosis invasiva y el perfil de susceptibilidad antibiótica de aislamientos de salmonela (2013-2017), en una serie de casos de pacientes con Salmonella spp. aislada de secreciones y/o líquidos corporales con o sin coprocultivo positivo (n=70). Para la evaluación de la susceptibilidad antibiótica se consideró el primer aislamiento en todos los casos de salmonelosis (n=168). La mayor frecuencia de casos ocurrió entre 0 a 4 años (14,3%) y mayores de 65 años (24,3%). Los síntomas más frecuentes fueron fiebre (66,1%), diarrea (40,7%) y trastorno del sensorio (40,7%). La infección por el virus de inmunodeficiencia humana (VIH) fue la comorbilidad más frecuente (42,4%). La frecuencia de susceptibilidad fue de 83,3% a ceftriaxona, 78,8% a cotrimoxazol y 75,0% a cloranfenicol. Sólo 50,8% fueron susceptibles a ciprofloxacino. Concluimos que, la salmonelosis invasiva fue más frecuente en niños pequeños y ancianos, y que la comorbilidad más frecuente fue la infección por VIH.

ABSTRACT The study's objective was to determine the epidemiological, clinical, and laboratory characteristics of cases of invasive salmonellosis and the antibiotic susceptibility profile of salmonella isolates (2013-2017), in a series of cases of patients with Salmonella spp. isolated from secretions and/or body fluids with or without positive stool culture (n=70). For the evaluation of antibiotic susceptibility, the first isolate was considered in all cases of salmonellosis (n=168). The highest frequency of cases occurred between 0 to 4 years (14.3%) and over 65 years (24.3%). The most frequent symptoms were fever (66.1%), diarrhea (40.7%), and sensory issues (40.7%). Human immunodeficiency virus (HIV) infection was the most common co-morbidity (42.4%). The frequency of susceptibility was 83.3% to ceftriaxone, 78.8% to cotrimoxazole, and 75.0% to chloramphenicol. Only 50.8% were susceptible to ciprofloxacin. We concluded that invasive salmonellosis was more common in young children and the elderly and that HIV infection was the most common comorbidity.

Ação de diferentes sanitizantes em biofilmes de Salmonella Minnesota / Action of different sanitizers in biofilmes of Salmonella Minnesota

Objetivou-se avaliar a eficiência do contato por 15 minutos do hipoclorito de sódio 1%, e ácido peracético 0,8% na inibição de biofilmes formad os por três cepas distintas de Salmonella Minnesota em aço, poliuretano e polipropileno e determinar a recuperação das células remanescentes. Qualitativamente houve influência na classificação dos biofilmes de acordo com a superfície, que foram diferentes dependendo do tipo de cepa e de material, porém a quantidade de células sésseis permanece constante, pois independente da cepa e da superfície, os biofilmes mantiveram uma contagem de 5,18 Log UFC, indicando que as diferenças referem-se à matriz polimérica. O uso do hipoclorito foi capaz de destruir as células, que não foram recuperadas após reincubação. Já o ácido peracético não promoveu redução significativa. O uso do hipoclorito de sódio 1% é eficiente na sua remoção.

Multidrogorresistencia de Salmonella infantis en Perú: un estudio mediante secuenciamiento de nueva generación / Multidrug resistance of Salmonella infantis in Peru: a study through next generation sequencing

RESUMEN Objetivos. Describir los patrones fenotípicos y genotípicos de la resistencia antimicrobiana de Salmonella Infantis en Perú. Materiales y Métodos. Se analizaron 297 cepas de Salmonella sp. remitidas al Instituto Nacional de Salud (INS) en el periodo 2014-2016. Las cepas fueron caracterizadas fenotípicamente mediante pruebas microbiológicas, serológicas y de susceptibilidad antimicrobiana. En base a los patrones de resistencia antimicrobiana se seleccionaron 46 cepas que fueron caracterizadas genéticamente mediante secuenciamiento de nueva generación. Resultados. Se identificaron 193/297 (65,0%) cepas de Salmonella Infantis, de la cuales 143 (74,1%) fueron multidrogorresistentes productoras de betalactamasas de espectro extendido (BLEE). Con el secuenciamiento genómico se evidenció un nuevo perfil para Salmonella Infantis, además, se identificó la presencia de 15 diferentes determinantes genéticos de resistencia a los antimicrobianos codificados en cromosoma bacteriano y cinco codificados en un megaplásmido. Los patrones de resistencia fenotípicos y genotípicos coincidieron, a excepción de la ceftazidima. Asimismo, las 46 cepas presentaron resistencia y/o sensibilidad disminuida a las quinolonas. Conclusiones. Salmonella Infantis se ha convertido en una de las serovariedades más frecuentemente referidas al INS, la cual incluye cepas multidrogoresistentes productoras de BLEE con resistencia a las quinolonas. Finalmente, se reafirma la relevancia del secuenciamiento de nueva generación en la caracterización de nuevas variantes de patógenos de importancia para la salud pública y su uso potencial en los sistemas de vigilancia de resistencia antimicrobiana.

ABSTRACT Objectives. To describe the phenotypic and genotypic patterns of the antimicrobial resistance of Salmonella Infantis in Peru. Materials and Methods. Two hundred and ninety-seven strains of Salmonella sp. submitted to the National Institute of Health (INS, in Spanish) during 2014-2016 were analyzed. The strains were phenotypically characterized by microbiological, serological, and antimicrobial susceptibility tests. Based on antimicrobial resistance patterns, 46 strains were selected and genetically characterized by next generation sequencing. Results. 193/297 (65%) strains of Salmonella Infantis were identified, of which 143 (74.1%) were multidrug-resistant producers of extended spectrum beta-lactamases (ESBL). The genomic sequencing evidenced a new profile for Salmonella Infantis; additionally, it identified the presence of 15 different genetic determinants of antimicrobial resistance coded in bacterial chromosome and five coded in a megaplasmid. The phenotypic and genotypic resistance patterns matched, with the exception of ceftazidime. Moreover, the 46 strains presented resistance and/or decreased sensitivity to quinolones. Conclusions. Salmonella Infantis has become one of the sero-varieties most frequently referred to the INS, which includes ESBLproducing multidrug-resistant strains with resistance to quinolones. Finally, the relevance of next generation sequencing is reasserted in the characterization of new variants of pathogens that are important for public health, and their potential use in antimicrobial resistance surveillance systems.

Caracterización de cepas clínicas y ambientales de Salmonella enterica subsp. enterica serovar Heidelberg aisladas en Chile / Characterization of Salmonella Heidelberg strains isolated in Chile

Background: Salmonella Heidelberg (S. Heidelberg) causes gastroenteritis and sometimes bacteremia and endocarditis. In other countries, this serovar has multidrug resistance including extended-spectrum β-lactamases (ESBLs) and AmpC (β-lactamases (AmpC), associated with the blaCMY-2 gene. In Chile, an outbreak by S. Heidelberg occurred in 2011, the phenotypic and genetic characteristics of Chilean strains are unknown. Aim: To determine the antimicrobial susceptibility, presence of plasmids and virulence factor genes in S. Heidelberg strains isolated in Chile over the period 2006-2011. Material and Methods: In sixty-one S. Heidelberg clinical and environmental strains collected by the Public Health Institute in Chile during 2006-2011, antimicrobial susceptibility, plasmids and virulence factor genes (invA, sifA, pefA, agfA, lpfA and, stkD) were studied. Results: S. Heidelberg had a high susceptibility to sulfamethoxazole-trimethoprim, gentamicin, ceftriaxone, ceftiofur, chloramphenicol, amoxicillin-clavulanic acid and ampicillin. However, 52% had decreased susceptibility to ciprofloxacin and 33% resistance to tetracycline. ESBLs were detected in three strains isolated from blood cultures, environment and human feces. The latter strain was positive for AmpC and blaCMY-2 gene. Fifty three of 61 strains showed one to seven plasmids of 0.8 to approximately 30 kb. Most plasmids were small with sizes between 0.8 and 2 kb. All isolates were positive for all genes except pefA. Conclusions: S. Heidelberg isolated from Chilean samples was susceptible to first-line antimicrobials, except tetracycline and ciprofloxacin. The emergence of strains with ESBLs and AmpC should be a warning. The strains were homogeneous for virulence genes, but heterogeneous in their plasmids.

Biofilm formation by Staphylococcus aureus and Salmonella spp. under mono and dual-species conditions and their sensitivity to cetrimonium bromide, peracetic acid and sodium hypochlorite

Abstract The aim of this study was evaluated the biofilm formation by Staphylococcus aureus 4E and Salmonella spp. under mono and dual-species biofilms, onto stainless steel 316 (SS) and polypropylene B (PP), and their sensitivity to cetrimonium bromide, peracetic acid and sodium hypochlorite. The biofilms were developed by immersion of the surfaces in TSB by 10 d at 37 °C. The results showed that in monospecies biofilms the type of surface not affected the cellular density (p > 0.05). However, in dual-species biofilms on PP the adhesion of Salmonella spp. was favored, 7.61 ± 0.13 Log10 CFU/cm2, compared with monospecies biofilms onto the same surface, 5.91 ± 0.44 Log10 CFU/cm2 (p < 0.05). The mono and dual-species biofilms were subjected to disinfection treatments; and the most effective disinfectant was peracetic acid (3500 ppm), reducing by more than 5 Log10 CFU/cm2, while the least effective was cetrimonium bromide. In addition, S. aureus 4E and Salmonella spp. were more resistant to the disinfectants in mono than in dual-species biofilms (p < 0.05). Therefore, the interspecies interactions between S. aureus 4E and Salmonella spp. had a negative effect on the antimicrobial resistance of each microorganism, compared with the monospecies biofilms.

Intereactions between doripenem and clavulanate ­ Application of minimal inhibitory concentration analysis and cytometry flow for bactericidal studies

Background: In view of the current low efficacy of bacterial infection treatment the common trend towards searching for antibiotic systems exhibiting synergistic action is well justified. Among carbapenem analogues a particularly interesting option is provided by combinations of clavulanic acid with meropenem, which have proven to be especially effective. Results: Determination of the minimal inhibitory concentration (MIC) along with the method based on flow cytometry constitutes an important tool in the identification of bacterial sensitivity to active substances. Within this study the inhibitory effect of doripenem, clavulanic acid and the doripenem-clavulanate acid system was analyzed in relation to such bacteria as Salmonella enteritidis, Salmonella typhimurium, Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris, Clostridium butyricum and Clostridium pasteurianum, Acinetobacter baumannii, Enterobacter aerogenes. The lowest MIC, amounting to 0.03 µg/mL, was observed for the doripenem-clavulanate acid system in the case of E. coli ATCC 25922. In turn, the lowest MIC for doripenem applied alone was recorded for K. pneumoniae ATCC 31488, for which it was 0.1 µg/mL. The strain which proved to be most resistant both to doripenem and the doripenem-clavulanate acid system, was A. baumannii, with MIC of 32 µg/mL (clinical isolate) and 16 µg/mL (reference strain). Cytometric analysis for P. aeruginosa ATCC 27853 and S. aureus ATCC 25923 showed changes in cells following exposure to limiting concentrations of the active substance. Conclusions: Analysis of MIC supplies important information concerning microbial sensitivity to active substances, mainly in terms of limiting concentrations causing mortality or vitality of the tested species, which is essential when selecting appropriate antibiotic therapy.

Severe sepsis from a Ciprofloxacin resistant salmonellosis in a kidney transplant recipient / Sepse grave por salmonelose Ciprofloxacino-resistente em paciente transplantado renal

Abstract Introduction: Salmonellosis is a relatively rare complication in kidney transplant recipients that cannot be clinically distinguished from other forms of enteritis. Among kidney transplant patients, it varies broadly in intensity, and is highly associated with extra-intestinal disease, bacteremia, and, in this case, a high mortality rate. Case Report: Here we describe a clinical case of ciprofloxacin resistant salmonellosis in a kidney transplant patient. Conclusion: This case illustrates how immunosuppressed patients can be exposed to rare forms of infection, often clinically difficult to identify, and possibly with severe clinical courses and poor outcomes despite evidence-based empiric antibiotic therapy.

Resumo Introdução: A salmonelose é uma complicação relativamente rara em transplantados renais, e não pode ser diferenciada de outras formas de enterite pela apresentação clínica. Em pacientes transplantados renais, a salmonelose varia em gravidade, e é frequentemente associada com formas extra intestinais, bacteremia, e, neste caso, com elevada mortalidade. Relato de Caso: Descrevemos o caso clínico de um paciente transplantado renal com salmonelose Ciprofloxacino-resistente. Conclusão: Este caso ilustra o risco, relacionado à imunossupressão, da ocorrência de formas raras de infecção, por vezes de difícil diagnóstico, e com cursos clínicos potencialmente graves e prognóstico ruim, apesar do emprego de antibioticoterapia empírica adequada e de acordo com as evidências disponíveis.

CTX-M extended-spectrum ß-lactamase-producing Klebsiella spp, Salmonella spp, Shigella spp and Escherichia coli isolates in Iranian hospitals

Abstract This study was conducted in Iran in order to assess the distribution of CTX-M type ESBLs producing Enterobacteriaceae. From January 2012 to December 2013, totally 198 E. coli, 139 Klebsiella spp, 54 Salmonella spp and 52 Shigella spp from seven hospitals of six provinces in Iran were screened for resistance to extended-spectrum cephalosporins. After identification and susceptibility testing, isolates presenting multiple-drug resistance (MDR) were evaluated for ESBL production by the disk combination method and by Etest using (cefotaxime and cefotaxime plus clavulanic acid). All isolates were also screened for bla CTX-M using conventional PCR. A total of 42.92%, 33.81%, 14.81% and 7.69% of the E. coli, Klebsiella spp, Salmonella spp and Shigella spp isolates were MDR, respectively. The presence of CTX-M enzyme among ESBL-producing isolates was 85.18%, 77.7%, 50%, and 66.7%, in E. coli, Klebsiella spp, Salmonella spp and Shigella spp respectively. The overall presence of CTX-M genes in Enterobacteriaceae was 15.4% and among the resistant isolates was 47.6%. This study indicated that resistance to β-lactams mediated by CTX-M enzymes in Iran had similar pattern as in other parts of the world. In order to control the spread of resistance, comprehensive studies and programs are needed.

Perfil de resistencia a antibióticos de serotipos de Salmonella spp. aislados de carne de res molida en la Ciudad de México / Antibiotic of resistence profile of Salmonella spp. serotypes isolated from retail beef in Mexico City

Resumen: Objetivo: Determinar el serotipo y perfil de resistencia a antibióticos de cepas de Salmonella spp. presentes en la carne de res que se expende en la capital mexicana. Material y métodos: Se analizaron 100 muestras de carne molida. Se aisló el patógeno por métodos convencionales y se confirmó por PCR (gen InvA, 284 pb). El perfil de resistencia a antibióticos se determinó por el método de Kirby-Bauer y la serotipificación por el esquema de Kauffman-White. Resultados: Se detectaron los serotipos Lomita (6), Derby (4), Senftenberg (2), Javiana y Cannsttat (1). Se observó alta resistencia a ampicilina (18/19), carbenicilina (16/19), tetraciclina (13/19) y trimetoprim-sulfametoxasol (13/19). Cinco cepas fueron no tipificables y 14 mostraron multirresistencia. Conclusiones: La carne de res que se vende en el principal centro de consumo del país está contaminada con serotipos de Salmonella spp. relevantes para la salud pública. Una importante proporción de éstos es resistente a múltiples antibióticos.

Abstract: Objective: To determine the serotype and antibiotic resistance profile of Salmonella spp. isolated from retail ground beef in Mexico City. Materials and methods: A total of 100 samples of ground beef were analyzed. The pathogen was isolated by conventional methods and confirmed by PCR (invA gene, 284 bp).The antibiotic resistance profile was determined by the Kirby-Bauer method while serotyping was performed according to the Kauffman-White scheme. Results: We isolated a total of 19 strains of Lomita (6), Derby (4), Senftenberg (2), Javiana and Cannsttat (1) and undetermined (5) serotypes. The strains showed a high resistance rate to ampicillin (18/19), carbenicillin (16/19), tetracyclin (13/19), and trimethoprim-sulfamethoxazole (13/19). Multidrug resistance was observed in 14 isolates. Conclusions: Several Salmonella spp. serotypes of public health significance are circulating in ground beef sold in the major Mexican city. Some of these strains are multi-drug resistance.

Multidrug resistance and ESBL-producing Salmonella spp. isolated from broiler processing plants

Abstract The aim of this study was to investigate the occurrence of multidrug-resistant, extended spectrum beta-lactamase (ESBL) producing Salmonella spp. isolated from conveyor belts of broiler cutting rooms in Brazilian broiler processing plants. Ninety-eight strains of Salmonella spp. were analyzed. Multidrug resistance was determined by the disk diffusion test and the susceptibility of the isolated bacteria was evaluated against 18 antimicrobials from seven different classes. The double disk diffusion test was used to evaluate ESBL production. Of the 98 strains tested, 84 were multidrug resistant. The highest rates of resistance were against nalidixic acid (95%), tetracycline (91%), and the beta-lactams: ampicillin and cefachlor (45%), followed by streptomycin and gentamicin with 19% and 15% of strain resistance, respectively. By contrast, 97% of the strains were sensitive to chloramphenicol. 45% of the strains were positive for the presence of ESBL activity. In this study, high rates of multidrug resistance and ESBL production were observed in Salmonella spp.

Biocide tolerance in Salmonella from meats in Southern Spain

Salmonella serovars sampled from meat products in Southern Spain (Andalucía) during the period 2002-2007 were analyzed in this study. The serovars most frequently detected (in order) were Typhimurium, Enteritidis, Derby, Anatum and Rissen. Isolates (n = 43) were tested for sensitivity to biocides, including the quaternary ammonium compounds benzalkonium chloride (BC), cetrimide (CT) and hexadecylpyridinium chloride (HDP), and the bisphenols triclosan (TC) and hexachlorophene (CF). The minimum inhibitory concentration (MIC) for the quaternary ammonium compounds was in the range of 25 to 50 mg/L for most isolates, although a few isolates required much higher concentrations, up to 250 mg/L. Bisphenols showed higher inhibitory activity, with a MIC of 2.5 to 25 mg/L. A few isolates showed a “non-wildtype” MIC for TC of up to 250 mg/L. These results indicate a low incidence of tolerance towards quaternary ammonium compounds and triclosan among Salmonella from meats and meat products.

Studies of genotoxicity and mutagenicity of nitroimidazoles: demystifying this critical relationship with the nitro group

Nitroimidazoles exhibit high microbicidal activity, but mutagenic, genotoxic and cytotoxic properties have been attributed to the presence of the nitro group. However, we synthesised nitroimidazoles with activity against the trypomastigotes of Trypanosoma cruzi, but that were not genotoxic. Herein, nitroimidazoles (11-19) bearing different substituent groups were investigated for their potential induction of genotoxicity (comet assay) and mutagenicity (Salmonella/Microsome assay) and the correlations of these effects with their trypanocidal effect and with megazol were investigated. The compounds were designed to analyse the role played by the position of the nitro group in the imidazole nucleus (C-4 or C-5) and the presence of oxidisable groups at N-1 as an anion receptor group and the role of a methyl group at C-2. Nitroimidazoles bearing NO2 at C-4 and CH3 at C-2 were not genotoxic compared to those bearing NO 2 at C-5. However, when there was a CH3 at C-2, the position of the NO2 group had no influence on the genotoxic activity. Fluorinated compounds exhibited higher genotoxicity regardless of the presence of CH3 at C-2 or NO2 at C-4 or C-5. However, in compounds 11 (2-CH3; 4-NO2; N-CH2OHCH2Cl) and 12 (2-CH3; 4-NO2; N-CH2OHCH2F), the fluorine atom had no influence on genotoxicity. This study contributes to the future search for new and safer prototypes and provide.

ß-defensin-2 in breast milk displays a broad antimicrobial activity against pathogenic bacteria / ß-defensina 2 no leite materno mostra uma ampla atividade antimicrobiana contra bactérias patogênicas

OBJECTIVE: To describe the antimicrobial activity of ß-defensin-2 produced in the mammary gland and secreted in human breast milk. METHODS: The peptide production was performed by DNA cloning. ß-defensin-2 levels were quantified in 61 colostrum samples and 39 mature milk samples from healthy donors, by an indirect enzyme-linked immunosorbent assay (ELISA). Using halo inhibition assay, this study assessed activity against seven clinical isolates from diarrheal feces of children between 0 and 2 years of age. The activity of ß-defensin-2 against three opportunistic pathogens that can cause nosocomial infections was determined by microdilution test. RESULTS: The peptide levels were higher in colostrum (n = 61) than in mature milk samples (n = 39), as follows: median and range, 8.52 (2.6-16.3) µg/ml versus 0.97 (0.22-3.78), p < 0.0001; Mann-Whitney test. The recombinant peptide obtained showed high antimicrobial activity against a broad range of pathogenic bacteria. Its antibacterial activity was demonstrated in a disk containing between 1-4 µg, which produced inhibition zones ranging from 18 to 30 mm against three isolates of Salmonella spp. and four of E. coli. ß-defensin-2 showed minimum inhibitory concentrations (MICs) of 0.25 µg/mL and 0.5 µg/mL for S. marcescen and P. aeruginosa, respectively, while a higher MIC (4 µg/mL) was obtained against an isolated of multidrug-resistant strain of A. baumannii. CONCLUSIONS: To the authors' knowledge, this study is the first to report ß-defensin-2 levels in Latin American women. The production and the activity of ß-defensin-2 in breast milk prove its importance as a defense molecule for intestinal health in pediatric patients. .

OBJETIVO: Descrever a atividade antimicrobiana da defensina-beta 2 na glândula mamária e secretada no leite materno humano. MÉTODOS: A produção de peptídeos foi realizada por clonagem de DNA. Os níveis de defensina-beta 2 foram quantificados em 61 amostras de colostro e 39 de leite maduro de doadoras saudáveis pelo teste ELISA indireto. Por um ensaio de halo de inibição, avaliamos a atividade contra sete isolados clínicos diarreicos de crianças entre 0 e 2 anos. A atividade da defensina 2 contra três patógenos oportunistas que podem causar infecções nosocomiais foi determinada pelo teste de microdiluição. RESULTADOS: Os níveis de peptídeos estavam significativamente maiores nas amostras de colostro (n = 61) que de leite maduro (n = 39), como segue: 8,52 (2,6-16,3 µg/mL) mediana e faixa em comparação a 0,97 (0,22-3,78), p < 0,0001; teste de Mann-Whitney. O peptídeo recombinante foi obtido da alta atividade antimicrobiana demonstrada contra uma ampla gama de bactérias patogênicas. Sua atividade antibacteriana foi demonstrada em um disco contendo entre 1-4 µg, que produziu zonas de inibição entre 18 e 30 mm contra três isolados de Salmonella spp. e quatro de E. coli. A defensina-beta 2 demonstrou concentrações inibitórias mínimas (CIMs) de 0,25 µg/mL e 0,5 µg/mL para S. marcescen and P. aeruginosa, ao passo que uma CIM maior (4 µg/mL) foi obtida contra um isolado de cepa multirresistente de A. baumannii. CONCLUSÕES: Até onde sabemos, este estudo é o primeiro a relatar níveis de defensina em mulheres da América Latina. A produção e a atividade da defensina 2 no leite materno comprovam sua importância como uma molécula de defesa para a saúde intestinal em pacientes pediátricos. .

PREVALENCE OF DRUG RESISTANCE AND VIRULENCE FEATURES IN Salmonella spp. ISOLATED FROM FOODS ASSOCIATED OR NOT WITH SALMONELLOSIS IN BRAZIL / Prevalência de resistência antimicrobiana e características de virulência em Salmonella spp. isoladas de alimentos associados ou não com salmonelose no Brasil

Salmonella is the most common etiological agent of cases and outbreaks of foodborne diarrheal illnesses. The emergence and spread of Salmonella spp., which has become multi-drug resistant and potentially more pathogenic, have increased the concern with this pathogen. In this study, 237 Salmonella spp., associated or not with foodborne salmonellosis in Brazil, belonging mainly to serotype Enteritidis, were tested for antimicrobial susceptibility and the presence of the virulence genes spvC, invA, sefA and pefA. Of the isolates, 46.8% were sensitive to all antimicrobials and 51.9% were resistant to at least one antimicrobial agent. Resistance to more than one antimicrobial agent was observed in 10.5% of the strains. The highest rates of resistance were observed for streptomycin (35.9%) and nalidixic acid (16.9%). No strain was resistant to cefoxitin, cephalothin, cefotaxime, amikacin, ciprofloxacin and imipenem. The invA gene was detected in all strains. Genes spvC and pefA were found in 48.1% and 44.3% of strains, respectively. The gene sefA was detected in 31.6% of the strains and only among S. Enteritidis. Resistance and virulence determinants were detected in Salmonella strains belonging to several serotypes. The high rates of antibiotic-resistance in strains isolated from poultry products demonstrate the potential risk associated with the consumption of these products and the need to ensure good food hygiene practices from farm to table to reduce the spread of pathogens relevant to public health.

Salmonella é o agente etiológico mais comumente envolvido em casos e surtos de doenças diarréicas de origem alimentar. A preocupação com este patógeno é, ainda, maior quando se verifica o surgimento e a disseminação de cepas multirresistentes e potencialmente mais patogênicas. Neste estudo, 237 cepas Salmonella spp., associadas ou não com casos ou surtos de salmonelose e pertencentes, principalmente, ao sorovar Enteritidis, foram avaliadas quanto ao perfil de susceptibilidade antimicrobiana e presença dos genes de virulência spvC, invA, sefA e pefA. Entre as cepas avaliadas, 46,8% foram sensíveis a todos os agentes antimicrobianos e 51,9% foram resistentes a pelo menos uma droga. Multirresistência foi observada em 10,5% das cepas. As maiores taxas de resistência foram observadas para estreptomicina (35,9%) e ácido nalidíxico (16,9%). Não foram detectadas cepas resistentes à cefoxitina, cefalotina, cefotaxima, amicacina, ciprofloxaxina e imipenem. O gene invA foi detectado em todas as cepas de Salmonella. Os genes spvC e pefA foram encontrados em 48,1% e 44,3% das cepas, respectivamente. O gene sefA foi detectado em 31,6% das cepas, estando presente somente entre as cepas de S. Enteritidis. Resistência antimicrobiana e marcadores de virulência foram detectados em cepas de Salmonella pertencentes a diversos sorovares. A alta taxa de resistência antimicrobiana verificada em cepas isoladas de frangos e derivados demonstra o potencial risco associado ao consumo destes produtos e a necessidade de se assegurar boas práticas de higiene em toda cadeia produtiva para reduzir a disseminação de patógenos relevantes para a saúde pública.

Occurrence of Salmonella spp. and generic Escherichia coli on beef carcasses sampled at a brazilian slaughterhouse

A total of 120 beef carcasses were analyzed during processing at a slaughterhouse in southern Brazil. The carcasses were sampled by swab at three different steps of the slaughter line and then they were tested for Salmonella and E. coli. The Salmonella isolates were also examined for antimicrobial susceptibility. Salmonella prevalence distribution was modeled and the probability of contamination was simulated using @Risk program and 10,000 interactions. Results demonstrated that 4 beef carcasses (3.3%) were positive for Salmonella only in the first point. The six isolates of Salmonella were classified: S. Newport (n = 3), S. Saintpaul (n = 2) and S. Anatum (n = 1). No Salmonella strains exhibited resistance to any of the antimicrobials tested. As expected, the most contaminated point with E. coli was the first point (hide), presenting counts from 0.31 to 5.07 log cfu/100 cm². Much smaller E. coli counts were observed in the other points. Results indicated low levels of Salmonella and E. coli on the beef carcasses analyzed and also low probability of contamination of the carcasses by Salmonella, suggesting adequate microbiological quality.

Commercially laid eggs vs. discarded hatching eggs: contamination by Salmonella spp

Salmonella enterica is frequently associated with outbreaks of human salmonellosis, and products of avian origin, such as eggs and chicken meat, are the main vehicles of its transmission. The present study describes the occurrence of different serovars of Salmonella enterica and phagotypes of S. enterica serovar Enteritidis in eggs destined for human consumption. Four thousand eggs obtained from commercial egg laying farms and one thousand discarded hatching eggs from broiler farms, which were acquired at farmers' markets and informal shops, were analyzed. Salmonella spp. was isolated from 52.0% of the discarded hatching eggs, in which the predominant serovar was Enteritidis (84.6%), and the predominant Salmonella Enteritidis phagotype (PT) was PT7 (26.9%). Salmonella spp. was not isolated from eggs obtained from commercial egg laying farms. The antimicrobial resistance profile showed that 23.1% (n = 6) of the SE strains were resistant to nalidixic acid. The results suggest that the consumption of discarded hatching eggs represents an important source of Salmonella transmission to humans.

Dos aislamientos de Salmonella Infantis multirresistentes se comportan como hipoinvasivos pero con elevada proliferación intracelular

En este trabajo se investigó la presencia de determinantes característicos de plásmidos de virulencia en dos aislamientos clínicos de Salmonella Infantis portadores de plásmidos de multirresistencia. Además, se estudió la capacidad de invasión y proliferación en células eucariotas no fagocíticas. Ninguno de los aislamientos de S. Infantis mostró los determinantes genéticos que caracterizan a los plásmidos de virulencia para este género (operón spv). Los ensayos de invasión sobre líneas celulares eucariotas mostraron que los aislamientos de S. Infantis presentan una capacidad de invasión disminuida pero persisten y proliferan en el citoplasma, independientemente de utilizar una línea celular permisiva (HeLa) o no permisiva (NRK) para tal fin. Finalmente, no se observaron indicios microscópicos que podrían hacer sospechar un efecto bactericida de estas líneas celulares sobre los aislamientos estudiados.

Two multidrug-resistant Salmonella Infantis isolates behave like hypo-invasive strains but have high intracellular proliferation. In this work, plasmid-encoded virulence factors in two Salmonella Infantis isolates carrying multiresistance plasmids were investigated. In addition, their invasion and proliferative ability in non-phagocytic cells was studied. None of them showed the typical determinants of virulence plasmids (spv operon). The invasion assays of S. Infantis isolates on eukaryotic cells showed a decreased ability to Invade but they remained and proliferated In the cytoplasm regardless of having used a permissive (HeLa) or non-permissive (NRK) cell line. Finally, there was no microscopic evidence suggesting a bactericidal effect of these eukaryotic cell lines on the Isolates tested.

Prevalence and antimicrobial resistance of Salmonella in chicken carcasses at retail in 15 Brazilian cities / Prevalencia y resistencia a los antimicrobianos de Salmonella en polloscongelados de venta al por menor en 15 ciudades del Brasil

Objetivo. Describir la prevalencia y la resistencia a los antibióticos de Salmonella spp. en canales de pollo congeladas de venta al por menor en 15 ciudades del Brasil. Métodos. Entre septiembre del 2004 y julio del 2006 se llevó a cabo un estudio descriptivo de los datos del Programa Nacional Brasileño de Vigilancia de la Prevalenciade la Resistencia Bacteriana en el Pollo (PREBAF). Durante el programa serecolectaron canales de pollo en 15 capitales estatales del Brasil, en las cinco regiones geográficas del país. Para aislar Salmonella spp. e identificar los serotipos, se usaron las técnicas convencionales. Para evaluar la resistencia frente a 18 antibióticos, se usó el método de la concentración inhibitoria mínima. Resultados. En las 2 679 canales de pollo examinadas, la prevalencia de Salmonella spp. fue de 2,7% (amplitud, 0,0%–8,9%). El 50,6% de las muestras positivas provinieron del estado de São Paulo. Se identificaron 18 serotipos. Los más frecuentes fueron Salmonella Enteritidis (48,8%), Salmonella Infantis (7,6%), Salmonella Typhimurium (7,2%) y Salmonella Heidelberg (6,4%). Las 250 cepas evaluadas fueron resistentes auno o más antibióticos, y 133 (53,2%) fueron multirresistentes (≥ 3 clases de antibióticos). Salmonella Heidelberg fue resistente a la ceftriaxona (75,0%) y al ceftiofur (43,8%). Conclusiones. La prevalencia de Salmonella spp. en este estudio fue relativamente baja. Sin embargo, hubo una proporción elevada de cepas multirresistentes, inclusivea las cefalosporinas de tercera generación usadas para tratar la salmonelosis invasora. Los resultados confirman la relevancia del programa PREBAF, el cual se recomienda mejorar, por ejemplo, mediante un análisis oportuno de los datos. También es necesario revisar los límites permitidos de Salmonella spp. en el pollo que se vende al por menor en el Brasil.

Objective. To describe the prevalence and antimicrobial resistance of Salmonella spp. in frozen chicken carcasses at retail from 15 Brazilian cities. Methods. A descriptive study of data from the Brazilian National Program for Monitoring the Prevalence of Bacterial Resistance in Chicken (PREBAF) was conducted from September 2004 to July 2006. The program collected chicken carcasses in 15 state capitals of Brazil inthe five geographic regions of the country. Standardized methodologies were used to isolate Salmonella spp. and identify serotypes. The minimal inhibitory concentration method wasused to test resistance to 18 antimicrobials. Results. In 2 679 carcasses examined, the prevalence of Salmonella spp. was 2.7% (range0.0%–8.9%). São Paulo State produced 50.6% of positive samples. Eighteen serotypes were identified. The most frequently occurring were Salmonella Enteritidis (48.8%), Salmonella Infantis (7.6%), Salmonella Typhimurium (7.2%), and Salmonella Heidelberg (6.4%). All 250 strains tested were resistant to one or more antibiotics, and 133 (53.2%) were multidrug resistant (≥ 3 classes). S. Heidelberg was resistant to ceftriaxone (75.0%) and to ceftiofur (43.8%).Conclusions. The prevalence of Salmonella spp. found in this study was relatively low. However, there were a high proportion of multidrug-resistant strains, including thirdgenerationcephalosporins used to treat invasive salmonellosis. The results confirm the relevance of the PREBAF program. It is recommended that PREBAF be improved, including a timely data analysis. A review of permitted limits for Salmonella spp. in retail chicken in Brazil is also needed.