Frequency of Plasmid-Mediated AmpC ß-Lactamases in Escherichia coli Isolates from Urine Samples in São Paulo, Brazil.

Plasmid-mediated AmpC ß-lactamases (PMACBLs) in Enterobacteriaceae encode resistance to third-generation cephalosporins, and these can mediate carbapenem resistance when associated with porin loss. However, no standardized phenotypic method is available for detecting these enzymes in the clinical microbiology laboratory. Limited data are available concerning the frequency of PMACBLs in Enterobacteriaceae in Brazil. This study was conducted in response to an increased cefoxitin (CFO) resistance rate of 3.7% in Escherichia coli isolates from urine samples from patients with suspected urinary tract infections during 2010. We collected 2,266 E. coli isolates prospectively during January 2012. A total of 109 (4.8%) isolates were nonsusceptible to CFO. These strains were further examined using multiplex PCR for the presence of genes encoding PMACBLs and using inhibitor assays with CFO and ceftazidime (CAZ) disks with and without phenylboronic acid. Pulsed-field gel electrophoresis was used to evaluate clonal dissemination. Genes encoding PMACBLs were detected in 1.8% of the isolates from inpatients and 0.46% of isolates from outpatients. The most prevalent gene was blaCMY-2 and blaCMY-4 was also detected. The phenotypic analysis showed 100% sensitivity and specificity for CMY-2 and CMY-4 when CFO-resistant isolates with a minimum zone diameter difference of 5 mm for CAZ or CAZ and CFO were considered positive. Although most of the isolates were nonclonal, one clonal group with two isolates was observed. Thus, the most frequent PMACBL in E. coli from São Paulo, Brazil is CMY-2, and both clonal and plasmid-mediated dissemination occur.

Community-acquired Pseudomonas aeruginosa-pneumonia in a previously healthy man occupationally exposed to metalworking fluids.

Although the Pseudomonas aeruginosa infection is well known and frequently found in hospitals and nursing care facilities, many cases are also reported outside these boundaries. In general, this pathogen infects debilitated patients either by comorbidities or by any form of immunodeficiency. In cases of respiratory infection, tobacco abuse seems to play an important role as a risk factor. In previously healthy patients, community-acquired pneumonia (CAP) with P. aeruginosa as the etiological agent is extremely rare, and unlike the cases involving immunocompromised or hospitalized patients, the outcome is severe, and is fatal in up to 61.1% of cases. Aerosolized contaminated water or solutions are closely linked to the development of respiratory tract infection. In this setting, metalworking fluids used in factories may be implicated in CAP involving previously healthy people. The authors report the case of a middle-aged man who worked in a metalworking factory and presented a right upper lobar pneumonia with a rapid fatal outcome. P. aeruginosa was cultured from blood and tracheal aspirates. The autopsy findings confirmed a hemorrhagic necrotizing pneumonia with bacteria-invading vasculitis and thrombosis. A culture of the metalworking fluid of the factory was also positive for P. aeruginosa. The pulsed-field gel electrophoresis showed that both strains (blood culture and metalworking fluid) were genetically indistinguishable. The authors highlight the occupational risk for the development of this P.aeruginosa-infection in healthy people.

Faringoamidalite estreptocócica: comparação entre diagnóstico clínico e microbiológico / Streptococcal pharyngitis: comparison between the clinical and microbiological diagnosis

Introdução: Faringoamidalite é queixa frequente nos pronto-socorros pediátricos, com presença do Streptococcus pyogenes em 20 por cento dos casos. Os sinais e sintomas clínicos são insuficientes para diferenciar quadros virais dos bacterianos. Os métodos microbiológicos, teste rápido(TR) e cultura orofaringe(CO) são indispensáveis para diagnóstico e redução de antibióticos...

Introductions: Pharyngitis is a common complaint in the emergency room for children, with the presence of Streptococcus pyogenes in 20 per cent of the cases. The clinical signs and symptoms are insufficient to differentiate viral from bacterial infections. The microbiological methods, rapid test (RT) and oropharynx cultura (OC), are essential for diagnosis and for reducing the use of antibiotics...

Análise crítica da pseudosepticemia e falso negativo: valor diagnóstico das hemoculturas / Critical analysis of the pseudosepticemia and false negative: diagnostic value of the hemoculturas

A septicemia é uma das causas de morbidade e mortalidade em crianças e adultos. A dificuldade diagnóstica está associada tanto à obtenção de amostras, assim como ao sistema utilizado na cultura, seja automatizada ou manual. O objetivo foi determinar a freqüência de pseudosepticemia e falso negativo nos procedimentos automatizados e manuais em hemoculturas de dois centros diagnósticos: Hospital Universitário e um Centro de Análises e Pesquisas Clínicas. Utilizou-se Bactec 9240 e 9050 para hemocultura de 973 amostras, seguido de cultura em Agar sangue, Agar chocolate, MacConkey e Sabouraud. A identificação bacteriana foi realizada pelo sistema Vitek (automatizado) e manual utilizando provas bioquímicas em tubos. Estudo comparativo entre o sistema automatizado e o manual foi realizado utilizando 41 amostras de sangue. Os resultados mostram 12,33 porcento de positividade no total em ambos os centros. Das 932 culturas realizadas 3,86 porcento foram consideradas pseudo septicemias, e 8,47 porcento septicemias. As pseudo septicemias foram representadas por Staphylococcus coagulase negativa e as septicemias por: Staphylococcus aureus (19,0 porcento), Escherichia coli (13,9 porcento), Staphylococcus coagulase negativa (11,4 porcento), Acinetobacter baumanii (8,9 porcento ), Enterecoccus faecalis (7,6 porcento), Klebsiella pneumoniae (7,6 porcento), Enterobacter cloacae (5,1 porcento), Streptococcus pneumoniae (5,1 porcento ), outros (11,4 porcento) e leveduras (10 porcento ). Nas 41 culturas realizadas pelos sistemas automatizado e manual detectaram-se 5 e 3 amostras positivas, respectivamente, com resultado falso negativo de 40 porcento para o sistema manual. O percentual de hemoculturas positivas foi semelhante nos dois centros mostrando representatividade de amostra. A elevada incidência de pseudo septicemia enfatiza os cuidados pré-analíticos e a evidência de um alto percentual de resultados falsos negativo portanto não recomendando o uso do sistema manual para a rotina de hemoculturas.