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.

Reportamos o isolamento de Corynebacterium pseudodiphtheriticum de um caso de infecção cutânea. O paciente apresentou-se ao laboratório clínico com uma úlcera na perna esquerda. A coloração de Gram do material revelou a presença de bacilos Gram-positivos e ausência de outras espécies bacterianas. O organismo foi isolado em cultura pura no ágar sangue de carneiro e foi identificado como C. pseudodiphtheriticum através de um sistema de identificação comercial (API-Coryne, BioMérieux, França). A infecção foi tratada com sucesso através do uso de ciprofloxacina. Este caso reforça a importância do laboratório de microbiologia clínica na identificação de organismos Gram-positivos isolados de cultura pura de amostras de úlceras cutâneas.

We report here a rare case of cutaneous infection due to Corynebacterium pseudodiphtheriticum. The patient presented to the clinical laboratory with a skin ulcer on his left leg. Gram-stained preparation of the purulent secretion revealed the presence of numerous rod-shaped Gram-positive organisms in the absence of any other species. The organism was grown in pure culture on sheep blood agar and was further identified as C. pseudodiphtheriticum using a commercial identification system (API-Coryne, BioMérieux, France). The infection was successfully treated with ciprofloxacin. This case emphasizes the importance of the clinical microbiology laboratory in correctly identifying Gram-positive organisms obtained in pure culture from skin ulcers.

Detection of AmpC beta-lactamase production by enterobacteria has been problematic. Contrary to ESBLs, no specific guidelines are available for detection and confirmation of AmpC production by clinical relevant microorganisms. Moreover, some bacterial species may produce inducible AmpC beta-lactamases that can be easily overlooked by routine susceptibility tests. We reported here a new test based on the strong inducible effect of imipenem on AmpC genes and the consequent antagonism with ceftazidime. This test is very simple and proved to be helpful in detecting AmpC-inducible enzymes among several species of clinical isolates.

Corynebacterium species have often been considered normal skin flora or contaminants; however, in recent years they have been increasingly implicated in serious infections. Moreover, many new species have been discovered and old species renamed, especially after molecular biology techniques were introduced. Corynebacterium mucifaciens is mainly isolated from blood and from other normally-sterile body fluids; it forms slightly yellow, mucoid colonies on blood agar. We report a fatal case of bacteremia due to an atypical strain of C. mucifaciens. This strain had atypical colony morphology; analysis of the 16S rRNA gene was used to define the species.

Anaerobiospirillum succiniciproducens is an anaerobic, Gram-negative, spiral shaped bacteria, which is motile by means of bipolar tuffs of flagella. This organism appears to be a rare cause of bacteremia in humans, and it usually affects patients submitted to immunosuppressive therapy. Anaerobiospirillum succiniciproducens resembles Campylobacter spp. in Gram-stained preparations, however, it is considered resistant to most antimicrobial drugs that are used to treat Campylobacter infections. We observed Gram-negative, spiral shaped bacteria in Gram-stained preparations from blood culture flasks. Growth occurred only under anaerobic incubation, and identification to the species level was achieved by PCR amplification of the 16S rRNA gene, followed by direct sequencing and a GenBank homology search. To the best of our knowledge, this is the first reported Brazilian case of Anaerobiospirillum succiniciproducens bacteremia.

O uso de protocolos de controle de qualidade com padrões rígidos devem ser utilizados para garantir o isolamento dos microrganismos. Nosso objetivo foi o de avaliar um procedimento alternativo que nos permitisse detectar falhas de crescimento bacteriano em termos quantitativos, e comparação com o protocolo estabelecido pelo documento M22-A2 do NCCLS. Haemophilus influenzae apresentou diferença significativa de crescimento entre meio de cultivo de fontes distintas. Nos concluímos que, para alguns microrganismos fastidiosos, seja feita uma verificação quantitativa da capacidade de crescimento de cada meio de cultivo.

Stringent quality control protocols must be used in order to guaranty that a particular medium is able to recover all sort of organism that may be present in clinical samples. Our aim was to evaluate an alternative protocol that would allow us to detect medium failure to yield quantitative growth of selected pathogens, and compare with the document M22-A2 from NCCLS. The detection limit of Haemophilus influenzae was significantly different depending on media source. We conclude that for some fastidious microorganisms, quantitative verification of the growth capacity of the culture medium is advised.

É descrito o isolamento de uma cepa de Escherichia coli O91:H21 produtora de toxina Shiga (STEC) em associação com diarréia em uma criança da cidade de Porto Alegre, RS, Brasil. Dado o potencial para causar complicações graves, infecções por STECs deveriam ser melhor avaliadas em nossa população.

We describe the isolation of one strain of Shiga toxin-producing Escherichia coli O91:H21 from a child with diarrhea in the city of Porto Alegre, RS, Brazil. Considering the pathogenic potential of STEC, these organisms should be looked for more carefully among our population.