Molecular epidemiology of carbapenem-resistant Acinetobacter baumannii from southern Brazil / Epidemiologia molecular de Acinetobacter baumannii resistente aos carbapenêmicos provenientes do sul do Brasil / Epidemiología molecular de Acinetobacter baumannii resistente a carbapenem del sur de Brasil

Background and Objectives: carbapenem resistance in Acinetobacter baumannii has reached extremely high levels worldwide, and class D OXA-type carbapenemases are the main associated mechanism. This study aimed to assess the phenotypic and molecular profile of clinical carbapenem-resistant A. baumannii (CRAb) isolates from a southern Brazilian border region. Methods: A. baumannii species was identified by the presence of the blaOXA-51 gene, and the susceptibility profile was determined by broth microdilution. The main carbapenemases were investigated by PCR and the molecular typing was performed by PFGE. Results: during the study, a total of 36 CRAb were recovered, of which 85.7% were from respiratory tract samples from ICU patients. High level resistance to were found in contrast to 100% of susceptibility for polymyxin B. The blaOXA-23 gene was present in 34 isolates and was the only one detected other than blaOXA-51. Molecular typing revealed the presence of four clonal strains, two of them endemic during the period of the study. Conclusion: to the best of our knowledge, our study brings the first data about resistance profile in Acinetobacter in the western border of southern Brazil and make aware of endemic clones of CRAb-producing-OXA-23 in this region of state, contributing for the construction of the national epidemiologic scenario of CRAb.(AU)

Justificativa e Objetivos: a resistência aos carbapenêmicos em Acinetobacter baumannii atingiu níveis extremamente altos em todo o mundo, e as carbapenemases do tipo OXA classe D são o principal mecanismo associado. O objetivo deste estudo foi avaliar o perfil fenotípico e molecular de isolados clínicos de A. baumannii resistentes aos carbapenêmicos (CRAb) de uma região de fronteira do sul do Brasil. Métodos: a espécie A. baumannii foi identificada através da presença do gene blaOXA-51, e o perfil de sensibilidade foi determinado por microdiluição em caldo. As principais carbapenemases foram investigadas por PCR, e a tipagem dos isolados de CRAb foi realizada por PFGE. Resultados: durante o período do estudo, 36 CRAb foram recuperados, dos quais 85,7% foram provenientes de amostras do trato respiratório de pacientes de UTI. Uma elevada resistência a aminoglicosídeos e fluoroquinolonas foi encontrada em contraste com 100% de sensibilidade a polimixina B. O gene blaOXA-23 foi encontrado em 34 isolados e foi o único detectado além do blaOXA-51. A tipagem molecular revelou a presença de quatro linhagens clonais, duas delas endêmicas ao longo do período do estudo. Conclusão: nosso estudo traz os primeiros dados sobre o perfil de resistência em Acinetobacter na fronteira oeste do sul do Brasil e alerta para a presença de clones endêmicos de CRAb produtores de OXA-23 nessa região, contribuindo para a construção do cenário epidemiológico nacional de CRAb.(AU)

Justificación y Objetivos: la resistencia a carbapenémicos en Acinetobacter baumannii ha alcanzado niveles extremadamente altos en todo el mundo y las carbapenemases OXA de clase D son el principal mecanismo asociado. El objetivo de este estudio fue evaluar el perfil fenotípico y molecular de los aislados clínicos de A. baumannii resistentes a carbapenémicos (CRAb) de una región fronteriza en el sur de Brasil. Métodos: la especie A. baumannii se identificó a través de la presencia del gen blaOXA-51 y el perfil de sensibilidad se determinó por microdilución en caldo. Las principales carbapenemasas fueron investigadas por PCR y la tipificación se hizo con PFGE. Resultados: durante el período de estudio, se recuperaron 36 CRAb, 85,7% de muestras del tracto respiratorio de pacientes de la UCI. Se encontró una alta resistencia a los aminoglucósidos y las fluoroquinolonas en contraste con 100% de sensibilidad a polimixina B. El gen blaOXA-23 se encontró en 34 aislamientos y fue el único detectado además de blaOXA-51. La tipificación molecular reveló la presencia de cuatro cepas clonales, dos de ellas endémicas durante el período de estudio. Conclusiones: hasta donde sabemos, nuestro estudio trae los primeros datos sobre el perfil de resistencia en Acinetobacter en la frontera oeste del sur de Brasil y reconoce los clones endémicos de CRAb productores de OXA.(AU)

A practical molecular identification of nonfermenting Gram-negative bacteria from cystic fibrosis

Abstract Identification of nonfermenting Gram-negative bacteria (NFGNB) of cystic fibrosis patients is hard and misidentification could affect clinical outcome. This study aimed to propose a scheme using polymerase chain reaction to identify NFGNB. This scheme leads to reliable identification within 3 days in an economically viable manner when compared to other methods.

Antimicrobial susceptibility of Salmonella Gallinarum and Salmonella Pullorum isolated from ill poultry in Brazil / Suscetibilidade a antimicrobianos de Salmonella Gallinarum e Salmonella Pullorum isolados de aves doentes no Brasil

ABSTRACT: Salmonella Gallinarum (S. Gallinarum) and Salmonella Pullorum (S. Pullorum) are poultry host-specific, agents of fowl typhoid and pullorum disease, respectively. These biovars cause septicemic infections, resulting in high mortality. Outbreaks are frequently reported worldwide, causing losses due to the elimination of infected flocks and treatments. The use of antimicrobial agents is frequent in poultry farms to prevent or treat gastrointestinal infections. In the present research it was evaluated the antimicrobial susceptibility of 50 S. Gallinarum and S. Pullorum isolates, from outbreaks that occurred between 1987 to 1991 and 2006 to 2013. The comparison of the susceptibility profiles showed that all isolates were susceptible to β-lactams. All isolates from 1987-1991 were susceptible to all antibiotics tested except NAL and CIP (78%). The susceptibility profile of S. Gallinarum (2006 - 2013 period) was the following NAL (58%), CIP (63%), ENR (67%), TET (92%), FFC (96%) and SXT (96%). S. Pullorum isolates (2006 - 2013 period) showed the following susceptibility rates to NAL (65%), CIP (71%), ENR (94%) and TET (94%). All isolates were susceptible to β-lactams tested, however, resistance to quinolones and fluoroquinolones increased over time. Furthermore, low levels of resistance to other antibiotics were found in recent isolates, such as tetracyclines.

RESUMO: Salmonella Gallinarum (S. Gallinarum) e Salmonella Pullorum (S. Pullorum) são patógenos hospedeiro-específico de aves, agentes do tifo aviário e pulorose, respectivamente. Estes biovares causam infecções septicêmicas, resultando em alta mortalidade. Surtos são frequentemente relatados em diversos países, causando prejuízos devido à eliminação de lotes infectados e tratamentos. Agentes antimicrobianos são utilizados frequentemente em granjas avícolas para prevenir ou tratar infecções gastrointestinais. No presente trabalho, foi avaliada a susceptibilidade antimicrobiana de 50 isolados de S. Gallinarum e S. Pullorum, obtidos durante surtos que ocorreram entre 1987 a 1991 e entre 2006 a 2013. A comparação dos perfis de sensibilidade mostrou que todas as amostras são sensíveis aos β-lactâmicos. Todos os isolados de 1987-1991 foram sensíveis a todos os antibióticos testados, exceto NAL e CIP (78%). O perfil de susceptibilidade de S. Gallinarum (surtos de 2006 a 2013) foi NAL (58%), CIP (63%), ENR (67%), TET (92%), FFC (96%) e SXT (96%). Isolados de S. Pullorum (surtos de 2006 a 2013) apresentaram as seguintes taxas de sensibilidade: NAL (65%), CIP (71%), ENR (94%) e TET (94%). Todas as amostras foram sensíveis ao β-lactâmicos testados, no entanto, a resistência às quinolonas e fluoroquinolonas aumentou ao longo do tempo. Além disso, baixos níveis de resistência a outros antibióticos foram encontrados em isolados recentes, tais como as tetraciclinas.

Induction and nosocomial dissemination of carbapenem and polymyxin-resistant Klebsiella pneumoniae

Polymyxins are antimicrobial agents capable of controlling carbapenemase-producing Klebsiella pneumoniae infection.

Prior oropharyngeal colonization and ventilator-associated pneumonia

This study evaluated the relationship between previous colonization of the oropharynx and development of ventilator-associated pneumonia through the classification of genomic fingerprint pattern by pulsed-field gel electrophoresis of both oxacillin-resistant and oxacillin-susceptible Staphylococcus aureus isolates obtained from hospitalized patients in an intensive care unit.

Mutations in the quinolone resistance-determining regions of gyrA and parC in Enterobacteriaceae isolates from Brazil

Mutations in the quinolone resistance-determining regions (QRDR) in chromosomal gyrA and parC genes and fluoroquinolone susceptibility profiles were investigated in quinolone-resistant Enterobacteriaceae isolated from community and hospitalized patientsin the Brazilian Southeast region. A total of 112 nalidixic acid-resistant enterobacterial isolates collected from 2000 to 2005 were investigated for mutations in the topoisomerases genes gyrA and parC by amplifying and sequencing the QRDR regions. Susceptibility to fluoroquinolones was tested by the agar dilution method. Amongst the 112 enterobacterial isolates, 81 (72.3%) were resistant to ciprofloxacin and 5 (4.5%) showed reduced susceptibility. Twenty-six (23.2%) were susceptible to ciprofloxacin. Several alterations were detected in gyrA and parC genes. Escherichia coli isolates (47.7%) showed double mutations in the gyrA gene and a single one in the parC gene. Two unusual aminoacid substitutions are reported, an Asp87-Asn in a Citrobacter freundii isolate with reduced susceptibility to fluoroquinolones and a Glu84-Ala in one E. coli isolate.Only a parC gene mutation was found in fluoroquinolone-susceptible Enterobacter aerogenes. None of the isolates susceptible to ciprofloxacin presented mutations in topoisomerase genes. This comprehensive analysis of QRDRs in gyrA and parC genes, covering commonly isolated Enterobacteriaceae in Brazil is the largest reported up to now.

Prevalência de Staphylococcus aureus na saliva de trabalhadores de saúde / Prevalence of Staphylococcus aureus in saliva of healthcare workers

Introdução: O estado de portador de Staphylococcus aureus resistente à meticilina é apontado como preditor de infecção e fator para a disseminação ambiental e de pessoa a pessoa, incluindo trabalhadores de serviço de saúde. Estes quando colonizados são freqüentemente associados a surtos. Objetivo: Analisar a prevalência de Staphylococcus aureus na saliva de trabalhadores de hospital universitário. Metodologia: Estudo epidemiológico longitudinal realizado em Curitiba, Paraná, Brasil, com 486 trabalhadores no período de abril de 2006 a junho de 2008 compreendeu a coleta de três amostras de saliva e aplicação de instrumento de coletade dados. Staphylococcus aureus foram isolados dos espécimes clínicos e caracterizados fenotipicamente. Os dados foram organizados e processados no Programa EPI-Info e analisados por meio de estatística descritiva. Resultados: Entre os trabalhadores investigados, 60,9 por cento estavam colonizados por Staphylococcus aureus na saliva,sendo 67.9 por cento carreadores transitórios e 32.1 por cento carreadores persistentes; a prevalência de Staphylococcus aureus resistenteà meticilina (MRSA) entre os isolados foi de 15.7 por cento. A prevalência média de MRSA foi de 12.7 por cento sendo maior entre técnicos em enfermagem (21.4 por cento) e auxiliares de limpeza (20.6 por cento) e menor entre enfermeiros (4.5 por cento) e médicos (5.9 por cento). Conclusões: Os trabalhadores apresentaram alta prevalência de Staphylococcus aureus na saliva, indicando a boca como importante sítio corporal para a investigação da colonização por MRSA e potencial fonte para sua disseminação.

Background: The carrier state of methicillin-resistant Staphylococcus aureus is pointed as an infection predictor and a factor for environmental and person-to-person dissemination, including health service workers. These, when colonized are commonly associated to outbreaks. Objective: Analyze the prevalence of Staphylococcus aureus in saliva of workers at a university hospital.Methodology: Epidemiologic longitudinal study carried out in Curitiba, Paraná, Brazil, with 486 workers between April2006 and June 2008. Three saliva samples were collected and a data collection instrument was applied. Staphylococcus aureus were isolated from the clinical specimen and characterized by phenotypes. The data from the instrument and the laboratory results were organized and processed with EPIInfo software and analyzed via descriptive statistics. Results: Among the healthcare workers studied, 60.9%were colonized by Staphylococcus aureus in saliva; of those, 67.9% were transitory carriers and 32.1% were persistent carriers; the prevalence of meticillin-resistant Staphylococcusaureus (MRSA) among the isolated cases was 15.7%. The average prevalence of MRSA was 12.7% and higher among nurses’ aides (21.4%) and cleaning aides (20.6%) and loweramong nurses (4.5%) and doctors (5.9%). Conclusions: Healthcare workers presented high prevalence of Staphylococcus aureus in saliva, indicating the mouth as an important body site to investigate colonizationby MRSA and a potential source to its dissemination.

Intrahospital spread of carbapenem-resistant Pseudomonas aeruginosa in a University Hospital in Florianópolis, Santa Catarina, Brazil / Disseminação Intrahospitalar de Pseudomonas aeruginosa em Hospital Universitário de Florianópolis, Santa Catarina, Brasil

INTRODUCTION: Carbapenem-resistant Pseudomonas aeruginosa (CRPA) has been isolated with increasing frequency in Brazilian hospitals. Since June 2003, its detection in a teaching hospital in the city of Florianópolis, Brazil, has increased. This study aimed to investigate the minimal inhibitory concentration (MIC), presence of Metallo-β-lactamase (MβL) and a possible clonal relationship among the isolates. METHODS: The study included 29 CRPA and seven isolates with reduced susceptibility. The MIC was determined by agar-dilution. Detection of MβL was performed by Double Disk Sinergism (DDS) and Combined Disk (CD). The MβL gene was verified by PCR and nucleotide sequence analysis. Epidemiological typing was performed by pulsed-field gel electrophoresis. RESULTS: Among the 29 carbapenem-resistant isolates, polymyxin B presented 100 percent susceptibility and piperacillin/tazobactam 96.7 percent. Seventeen (62 percent) strains were verified as clonal (A clone) and among these, six isolates indicated phenotypically positive tests for MβL and harbored the blaSPM-1 gene. The first CRPA isolates were unrelated to clone A, harbored blaIMP-16 and were phenotypically positive only by CD. CONCLUSIONS: The spread of a high-level of resistance clone suggests cross transmission as an important dissemination mechanism and has contributed to the increased rate of resistance to carbapenems. This study emphasizes the need for continuous surveillance and improved strategies.

INTRODUÇÃO: O isolamento de Pseudomonas aeruginosa resistente aos carbapenêmicos (PARC) tem sido cada vez mais frequente nos hospitais brasileiros. O presente estudo investigou a concentração inibitória mínina (CIM), a presença de metalo-β-lactamases (MβL), e uma possível relação clonal entre PARC isoladas entre junho de 2003 a junho de 2005, em um hospital escola na cidade de Florianópolis, Brasil. MÉTODOS: O estudo incluiu 29 PARC e sete isolados com suscetibilidade reduzida. A CIM foi determinada por diluição em ágar. A detecção de MβL foi realizada por sinergismo de duplo disco (SDD) e disco combinado (DC). Genes para MβL foram pesquisados por PCR e confirmados pela análise da sequência de nucleotídeos. A tipagem epidemiológica foi realizada por gel de eletroforese em campo pulsátil. RESULTADOS: Entre os 29 isolados resistentes aos carbapenêmicos, 100 por cento apresentaram suscetibilidade a polimixina B, e 96,7 por cento a piperacilina/tazobactam. Dezessete (62 por cento) destes isolados pertenciam a um mesmo clone (clone A); entre estes, seis isolados apresentaram testes fenotípicos positivos para MβL e carreavam o gene blaSPM-1. O primeiro isolado PARC não foi relacionado ao clone A, carreava o gene blaIMP-16 e foi fenotipicamente positivo somente por DC. CONCLUSÕES: A propagação de um clone com alto nível de resistência sugere a transmissão cruzada como um importante mecanismo de disseminação e tem contribuído para o aumento nos níveis de resistência aos carbapenêmicos. Este estudo enfatiza a necessidade de vigilância contínua e melhoramento nas estratégias de controle de infecção nesta instituição.

First report of vancomycin-resistant Enterococcus faecalis in Uberaba, Minas Gerais state

In this study we report the first isolation of VanA-type vancomycin-resistant Enterococcus faecalis strains from two different patients hospitalized in the same intensive care unit at the hospital of Universidade Federal do Triângulo Mineiro (UFTM), Uberaba, Minas Gerais, Brazil.

Two outbreaks of mixed etiology associated with central venous catheters inserted by phlebotomy in critical neonates

Staphylococcus aureus and coagulase-negative staphylococci are the main cause of sepsis in Neonatal Intensive Care Unit (NICU). Central venous catheters (CVCs) are an important part of critical neonates' treatment and are associated with sepsis. The aim of this study was to investigate two outbreaks caused by Staphylococcus aureus and Staphylococcus epidermidis associated with CVC inserted by phlebotomy in critical neonates. The surveillance was performed from January 2001 to December 2005 at the Brazilian NICU. The genotypic analysis of oxacillin susceptible S. aureus (OSSA) and oxacillin resistant S. epidermidis (ORSE) was performed based on pulsed-field gel electrophoresis (PFGE). Staphylococcus was the most frequent pathogen (65.8 percent) with highest incidence of CoNS (59.9 percent) followed by S. aureus (40.1 percent). During the five years of surveillance, there were two outbreaks detected, occurred in January-February/02 and August/02 and confirmed by PFGE analysis. The predisposing factors for infection corresponding to both outbreaks were: age <7 days, hospitalization > 7 days, and use of polyethylene CVC through dissection of vein (phlebotomy). This is the first relate of staphylococcal outbreaks associated with CVC inserted by phlebotomy in NICU. PFGE showed polyclonal spread of OSSA during both epidemic and endemic period, and two monoclonal outbreaks of ORSE in the same epidemic period of OSSA.

Molecular characterization of enterococci harboring genotype and phenotype incongruence related to glycopeptide resistance isolated in Brazilian hospitals

Three Enterococcus faecalis and one Enterococcus faecium strains were characterized by plasmid profile, pulsed-field gel electrophoresis (PFGE) and determination of antimicrobial minimal inhibitory concentrations. VanA elements were characterized by Long PCR, overlapping PCR and DNA sequencing. Enterococcal strains showed resistance to vancomycin and harbored the vanA gene, and three these were teicoplanin susceptible while one showed intermediate resistance to teicoplanin. Two E. faecalis strains showed indistinguishable PFGE profile while the third was unrelated. E. faecalis strains showed a deletion in the right terminal region of the Tn1546-like element. The E. faecium strain showed an insertion element in the vanXY intergenic region. Mutations in VanA elements were not found. Rearrangements in the VanA element could be responsible for incongruities in genotype and phenotype in these strains.

Correlation between API 20 STREP and multiplex PCR for identification of Enterococcus spp. isolated from Brazilian foods

We evaluated the suitability of API 20 STREP and multiplex PCR to speciate 52 Enterococcus spp. obtained from Brazilian foods. A high percentage of isolates (78.9 percent) presented discrepant results between evaluated tests. Similar results were obtained for six E. faecalis and five E. faecium. The PCR multiplex was more effective than API 20 STREP for complete identification of the isolates.

A identificação das espécies de 52 Enterococcus spp. isolados de amostras de alimentos foi realizada empregando-se duas metodologias: sistema API 20 STREP e PCR multiplex. Os resultados obtidos revelaram que 78,9 por cento dos isolados apresentaram resultados diferentes nos dois testes utilizados. Apenas seis E. faecalis e cinco E. faecium apresentaram resultados concordantes pelos dois métodos. PCR multiplex permitiu a identificação completa de um número significantemente maior de enterococos do que o sistema API 20 STREP.

Vancomycin-resistant van a phenotype Enterococcus faecalis: first case in Minas Gerais state and epidemiological considerations

We report the first case of vancomycin-resistant Enterococcus faecalis with VanA phenotype and vanA genotype isolated from a surgical patient in a general Hospital in Uberlândia, state of Minas Gerais, Brazil.

Spread of a methicillin-resistant staphylococcus aureus clone isolated from bacteremia in elderly patients in a Brazilian general hospital

A study of the genomic diversity of MRSA strains isolated from elderly patients with infection/colonization in three repeated prevalence, cross sectional studies was performed in the 1999-2000 period. In this study, 13 MRSA isolates from blood cultures and 5 from rectal and nare cultures were obtained from 18 patients (13 elderly and 5 adults). Most of the patients were being treated with two or more antimicrobials (83.3%), had insertion of invasive devices (88.9%) and were managed in ICU (Intensive Care Unit) and/or surgical units (66.7%). MIC (Minimum Inhibitory Concentration) data showed that 88.9% of the MRSA strains were resistant to high concentrations of oxacillin (MIC > 256 ìg/mL), 94.5% of the MRSA carried the mecA gene in their genome, and most (65.0%) of the isolates were indistinguishable according to their DNA finger­printing generated by PFGE (Pulsed-field gel electrophoresis). Although PFGE typing was performed with a few MRSA isolates, our results demonstrate that one MRSA clone was associated with infection/colonization in patients with an obvious connection among five out of eleven patients who stayed in the same clinic and ICU during the same period. Hospital acquired infection, a major “silent epidemy”, is associated with prolonged hospital stay and high mortality rate and its cause must be better evaluated.

Identification and molecular characterization of Van A-type vancomycin-resistant Enterococcus faecalis in Northeast of Brazil

The isolation of vancomycin resistant enterococci (VRE) in Brazil has rapidly increased, following the world wide tendency. We report in the present study the first isolation of vancomycin resistant Enterococcus faecalis (VRE) in the Northeast of Brazil. The four VRE isolates were characterized for antimicrobial susceptibility, genotypic typing by macro restriction of chromosomal DNA followed by pulsed-field gel electrophoresis and for characterization of the Tn1546-like element and plasmid contents. The isolates showed resistance to multiple antibiotics and a single genotype profile, suggesting the dissemination of a single clone among the patients. Tn1546 associated to genetic elements as plasmids shows the importance of infection control measures to avoid the spreading of glycopetide resistance by conjugative transfer of VanA elements.

Virulence-associated characteristics of Enterococcus faecalis strains isolated from clinical sources

Thirty-two clinical isolates of Enterococcus faecalis were screened for virulence factors. Twenty-four (75 percent) isolates produced hemolysin on Mueller-Hinton blood agar plates with sheep erythrocytes. However, the cell free heat-stable hemolysin was detected in all isolates (100 percent) of E. faecalis when grown in BHI-GA (BHI medium supplemented with 1 percent glucose and 0.03 percent L-arginine), but not in BHI broth alone. Twenty-four isolates (75 percent) produced caseinase and 23 (71.9 percent) lipase, but none of the isolates produced gelatinase. Fifteen (46.9 percent) culture filtrates caused rounding and membrane alterations with blebbing formation followed by death in HeLa and HEp-2 cells, but not in Vero cells. Thirteen isolates (40.6 percent) agglutinated rabbit erythrocytes, but did not produce hemagglutination in other bloods, containing or not 1 percent D-manose. Sixteen (50 percent) E. faecalis isolates adhered to HeLa cells and thirteen (40.6 percent) to HEp-2 cells, but all isolates adhered to polypropylene microtiter plates, indicating that clinical E. faecalis possess the ability to form biofilm in vitro. All the isolates were resistant to the bactericidal action of normal serum and did not produce aerobactin. These findings suggest that adherence and consequently biofilm formation on ephitelial host cells are the first steps in the E. faecalis virulence and that hemolysin, lipase, caseinase and other virulence factors act as causative of human epithelial cell damages.

Foram estudados os fatores de virulência de trinta e duas amostras de Enterococcus faecalis, isolados de casos clínicos. Vinte e quatro amostras (75 por cento) produziram hemolisina em ágar sangue preparado com hemácias de carneiro. No sobrenadante da cultura em BHI nenhuma amostra produziu hemolisina, no entanto quando cultivadas em meio BHI suplementado com 1 por cento de glucose e 0,03 por cento de L-arginina (BHI-GA), 100 por cento das amostras lisaram hemácias de carneiro. Vinte e quatro (75 por cento) amostras produziram caseinase e 23 (71,9 por cento) lipase, mas nenhuma amostra produziu gelatinase. Dezesseis (46,9 por cento) causaram arredondamento e alteração na membrana das células, com formação de vesículas e, em seguida, a morte das células HeLa e HEp-2. Treze amostras (40,6) aglutinaram eritrócitos de coelhos, mas não aglutinaram outros eritrócitos na presença ou na ausência de 1 por cento de D-manose. Dezesseis (50 por cento) aderiram em células HeLa e 13 (40,6 por cento) em células HEp-2, mas todas as amostras de E. faecalis aderiram na microplaca de polipropileno, indicando que E. faecalis isolados de casos clínicos possuem capacidade de formar biofilme "in vitro". Todos os isolados mostraram-se resistentes à ação bactericida do soro normal e não produziram aerobactina. Esses resultados sugerem que, inicialmente, a colonização ou infecção por E. faecalis ocorre pela aderência e formação de biofilme nas células epiteliais e a produção de hemolisina, lípase e caseinase pode atuar como fatores de virulência na infecção por E. faecalis.

Outbreaks associated to bloodstream infections with Staphylococcus aureus and coagulase-negative Staphylococcus spp in premature neonates in a university hospital from Brazil

Staphylococcus aureus e Estafilococos coagulase-negativa (ECN) estão entre os patógenos hospitalares mais importantes em pacientes de unidades de terapia intensiva neonatal, principalmente em infecções da corrente sanguínea. O principal objetivo deste estudo foi determinar a ocorrência de infecções hospitalares por estes microrganismos usando dois sistemas de vigilância (laboratorial e "National Nosocomial Infection Surveillance" - NNIS) e determinar os fatores de risco mais importantes durante o período de dois anos (2001-2002). Dois surtos por ambos S. aureus suscetível a meticilina (1.5por cento) e ECN resistente à meticilina (1.0 por cento) foram observados, de janeiro a fevereiro/02 e agosto a setembro/02. Taxas de incidência endêmica de 3.77 por cento e 5.16 por cento para S.aureus e ECN foram detectadas respectivamente. Fatores de risco incluíram idade £7 dias, hospitalização 7 dias e utilização de cateter vascular central (CVC) de polietileno através de dissecação de veia (flebotomia), mas, nenhum desses fatores independentes foram confirmados pela análise multivariada. Por outro lado, ECN resistente à oxacilina prevaleceu (66.0 por cento) nos episódios epidêmicos. Análise molecular através de gel de eletroforese em campo pulsátil mostrou a natureza policlonal das amostras de S. aureus. Em conclusão, nós identificamos dois surtos de etiologia mista por S. aureus suscetível à meticilina e ECN resistente à meticilina associados à falta de material adequado (cateter vascular central) para neonatos, relacionados a procedimento invasivo. Os dois surtos foram controlados com a substituição de CVC de polietileno pelo cateter central de inserção periférica.

Emergence of VanB phenotype-vanA genotype in vancomycin-resistant enterococci in Brazilian hospital

No Brasil, enterococos resistente à vancomicina (VRE) têm sido descritos como patógenos hospitalares, desde 1998. Durante um monitoramento de VRE em um hospital, foram detectadas duas cepas de Enterococcus faecalis com genótipo vanA, e sensibilidade à teicoplanina. Este é o primeiro relato do isolamento de enterococo fenótipo VanB e genótipo vanA de amostra clínica no Brasil.

Eletroforese em campo pulsante em bacteriologia - uma revisão técnica / Pulsed field gel electrophoresis use in bacteriology - a technical review

PFGE (pulsed field gel eletrophoresis) é a sigla usada para indicar qualquer técnica de eletroforese apropriada para separar grandes fragmentos de DNA, por meio da reorientação do DNA em gel pela ação de campos elétricos alternados. Esta técnica é reconhecida como padrão ouro para identificação de linhagens bacterianas, fúngicas e de protozoários. O principal objetivo deste estudo de revisão é o da elucidação dos fundamentos da técnica de PFGE ou eletroforese de campo pulsante aplicada em estudo com bactéria. Sua resolução depende de uma série de fatores como: voltagem, concentração de agarose, temperatura, solução tamponante, tempo de pulso e de corrida eletroforética. A compreensão dos mecanismos moleculares envolvidos nesse tipo de eletroforese é fundamental para a otimização e obtenção dos resultados apropriados.

An outbreak of Acinetobacter baumannii septicemia in a neonatal intensive care unit of a university hospital in Brazil

We studied an outbreak of two multi-drug resistant clones of Acinetobacter baumannii in the Neonatal Intensive Care Unit of the Uberlândia Federal University Hospital in Minas Gerais state, Brazil, and we analyzed the contribution of cross-transmission in the rise in infection rates. Eleven neonates who developed multi-drug resistant A. baumannii nosocomial infection were matched to 22 neonates who were admitted to the same unit and did not develop an infection during the outbreak period, in order to identify risk factors for infection. Three out of the 11 neonates died. Epidemiological investigation included molecular typing, using pulsed field gel electrophoresis. Prior to the outbreak, from December 2001 to March 2002, no case of infection by this microorganism was diagnosed. Environmental and healthcare worker hand cultures were negative. Nine isolates had similar pulsed field gel electrophoresis patterns and two had another clone. The first clone was brought into the unit by an infected patient who was transferred from another hospital without a history of antibiotic use. The second clone did have its origin clearly defined. Both infected groups led us to conclude that several factors contributed to infection with A. baumannii. These factors were: exposure to antibiotics and invasive devices, birth weight < 1500g, age < 7 days and duration of hospitalization > 7 days. Based on logistic regression, infected neonates were more exposed to carbapenem and mechanical ventilation than the control group. Cross transmission between infants contributed to the rise in the rates of multi-drug resistant A. baumannii infection.