Abstract INTRODUCTION: Coagulase-negative staphylococci (CoNS) are a frequent cause of bacteremia, especially in neonates. The major virulence determinant in CoNS is the ability to produce biofilms, which is conferred by the icaADBC genes. This study aimed to assess different methods for the detection of biofilm formation in 176 CoNS isolates from blood cultures of newborns. METHODS: The presence of the icaACD genes was assessed by polymerase chain reaction (PCR), and biofilm formation was assessed on congo red agar (CRA), by the tube method (TM), and on tissue culture plates (TCP). RESULTS: Of the 176 CoNS isolates, 30.1% expressed icaACD and 11.4% expressed icaAD. The CRA assay and TM showed that 42% and 38.6% of the isolates were biofilm producing, respectively. On TCP, 40.9% of the isolates produced biofilms; 21% were weakly adherent and 19.9% were strongly adherent. When compared to the gold standard technique (PCR), the CRAassay showed 79% sensitivity and 84% specificity (kappa = 0.64), TM showed 78% sensitivity and 89% specificity (kappa = 0.68), and TCP showed 99% sensitivity and 100% specificity (kappa = 0.99). CONCLUSIONS: In this study, ~42% of CoNS isolates produced biofilms, and the presence of icaACD was associated with a greater capacity to form biofilms. Compared to the other phenotypic methodologies, TCP is an ideal procedure for routine laboratory use.

RESUMO Objetivou-se caracterizar fenotípica e genotipicamente isolados clínicos de enterobactérias resistentes aos carbapenêmicos (CRE) provenientes do Hospital Universitário de Santa Maria (RS). Entre os isolados clínicos submetidos ao teste modificado de Hodge (MHT), 62,5% apresentaram positividade, indicando possível produção de carbapenemase. A reação em cadeia da polimerase (PCR) demonstrou que o blaKPC foi o gene mais encontrado (31%), seguido de blaIMP (12,5%). O uso conjunto de distintas metodologias faz-se necessário para identificar a resistência aos carbapenêmicos produzida pelas enterobactérias, de modo a auxiliar o controle de infecção prevenindo a disseminação desses microrganismos.

ABSTRACT The present study aimed to genotypically and phenotypically characterize clinical isolates of carbapenem-resistant Enterobacteriaceae collected from inpatients at the University Hospital of Santa Maria, during seven months. Among the clinical isolates subjected to the modified Hodge test (MHT), 62.5% were positive, indicating possible production of carbapenemase. Polymerase chain reaction (PCR) demonstrated that blaKPC was the most frequently found gene (31%), followed by blaIMP (12.5%). Combined use of the methods is needed to identify carbapenem resistance in enterobacteria to prevent their spread and control the infections caused by these organisms.

Objetivo Analisar o perfil dos pacientes que apresentaram microrganismos com resistência aos carbapenêmicos, e a prevalência da enzima Klebsiella pneumoniae carbapenemase em enterobactérias. Métodos Estudo retrospectivo descritivo. A partir do isolamento em exames bacteriológicos solicitados pelos clínicos, descrevemos as características clínicas e epidemiológicas dos pacientes que apresentaram enterobactérias resistentes aos carbapenêmicos entre março e outubro de 2013 em um hospital universitário. Resultados Foram incluídos 47 pacientes isolados, todos apresentando resistência aos carbapenêmicos, dos quais 9 tiveram confirmação de infecção/colonização por K. pneumoniae carbapenemase. Ocorreu predomínio de isolamento em aspirados traqueais (12; 25,5%). A resistência ao ertapenem, meropenem e imipenem foi de 91,5%, 83,0% e 80,0%, respectivamente. Os aminoglicosídeos foram a classe de antimicrobianos que apresentou maior sensibilidade, sendo 91,5% sensível a amicacina e 57,4% a gentamicina. Conclusão A K. pneumoniae carbapenemase constituiu um importante patógeno hospitalar em isolamento crescente nesse nosocômio. As limitadas opções terapêuticas reforçam a necessidade de uma rápida detecção laboratorial, assim como a implementação de medidas de prevenção e controle da disseminação desses patógenos.

Objective To analyze the profile of patients with microorganisms resistant to carbapenems, and the prevalence of the enzyme Klebsiella pneumoniae carbapenemase in interobacteriaceae. Methods Retrospective descriptive study. From the isolation in bacteriological tests ordered by clinicians, we described the clinical and epidemiological characteristics of patients with enterobacteria resistants to carbapenems at a university hospital, between March and October 2013. Results We included 47 isolated patients in this study, all exhibiting resistance to carbapenems, including 9 patients who were confirmed as infected/colonized with K. pneumoniae carbapenemase. Isolation in tracheal aspirates (12; 25.5%) predominated. The resistance to ertapenem, meropenem, and imipenem was 91.5%, 83.0% and 80.0%, respectively. Aminoglycosides was the class of antimicrobials that showed the highest sensitivity, 91.5% being sensitive to amikacin and 57.4% to gentamicin. Conclusion The K. pneumoniae carbapenemase was an important agent in graun isotaling in hospital intection. The limited therapeutic options emphasize the need for rapid laboratory detection, as well as the implementation of measures to prevent and control the spread of these pathogens.

O gênero Enterococcus tem emergido como um dos mais importantes patógenos hospitalares no mundo inteiro. No presente estudo, a ocorrência das infecções enterocócicas por espécie e o sítio da infecção foram analisados. O Enterococcus faecalis foi a espécie de enterococo predominante em todos os isolamentos clínicos. Duzentos e trinta e três amostras de enterococos isoladas dos pacientes atendidos no Hospital Universitário de Santa Maria (HUSM) foram analisadas. A suscetibilidade antimicrobiana de alguns agentes foi também avaliada.

Members of the genus Enterococcus have emerged as the most important nosocomial pathogens worldwide.In the present study, the occurrence of enterococcal infections by species and site of infection was analyzed. Enterococcus faecalis was the predominant enterococci species among all clinical isolates. A total of 233 enterococci isolates obtained from patients of Hospital Universitário de Santa Maria were studied. Antimicrobial susceptibility to a variety of agents was also evaluated.