In this study, we aimed to evaluate the performance of different phenotypic tests to detect carbapenem-resistant Enterobacteriaceae. Three different phenotypic methods were evaluated: (1) combined-disk test of meropenem plus phenylboronic acid or EDTA reading after 24 h and 48 h; (2) selective/chromogenic read after 24 h and after 48 h; and (3) overnight selective enrichment broth containing 10 µg ertapenem disk followed by culture on MacConkey agar. A positive result in at least one of the methods was submitted to PCR for blaNDM-1, blaOXA-48, blaKPC, blaSPM-1, blaIMP, and blaGES detection. Carbapenem-resistant Enterobacteriaceae was detected in 31 (30.4%) of 102 rectal swabs evaluated. All isolates showed to be KPC-2-producing organisms. Results showed excellent agreement among the evaluated tests (positive and negative) (kappa = 0.88). It is important to state that combined-disk test with phenylboronic acid is not suitable for bacterial identification/isolation. Conversely, selective/chromogenic agar after 48h of incubation showed to be a useful tool, with the advantage of presumptive bacterial identification.

INTRODUÇÃO: Vigilância com base em detecção laboratorial é um componente importante no controle de enterococos resistentes a vancomicina (ERV). MÉTODOS: Avaliamos procedimento da reação em cadeia da polimerase real time (PCR-RT) (genes vanA-vanB) para detecção de ERV em 115 swabs de pacientes incluídos em um programa de vigilância. RESULTADOS: A sensibilidade do RT-PCR foi semelhante a da cultura primária (75% e 79,5%, respectivamente) quando comparada com a cultura em caldo enriquecido, enquanto a especificidade foi de 83,1%. CONCLUSÕES: O RT-PCR fornece resultados no mesmo dia, contudo mostra baixa sensibilidade para a detecção de VRE.

INTRODUCTION: Laboratory-based surveillance is an important component in the control of vancomycin resistant enterococci (VRE). METHODS: The study aimed to evaluate real-time polymerase chain reaction (RT-PCR) (genes vanA-vanB) for VRE detection on 115 swabs from patients included in a surveillance program. RESULTS: Sensitivity of RT-PCR was similar to primary culture (75% and 79.5%, respectively) when compared to broth enriched culture, whereas specificity was 83.1%. CONCLUSIONS: RT-PCR provides same day results, however it showed low sensitivity for VRE detection.