Helena Aguilar Peres Homem de Mello de Souza

Outbreak of Carbapenem-Resistant Acinetobacter baumannii Producing the OXA-23 Enzyme in Curitiba, Brazil

ABSTRACT Carbapenem-resistant Acinetobacter baumannii isolates were obtained from eight patients in two hospitals in Curitiba, Brazil. The isolates were multiresistant, belonged to a single strain, and produced the OXA-23 carbapenemase. Treatment options were limited, although the isolates were susceptible to polymyxin B in vitro. The strain contributed to the deaths of five patients.

Characterization of a Divergent vanD-Type Resistance Element from the First Glycopeptide-Resistant Strain of Enterococcus faecium Isolated in Brazil

ABSTRACT Enterococcus faecium 10/96A from Brazil was resistant to vancomycin (MIC, 256 μg/ml) but gave no amplification products with primers specific for known van genotypes. A 2,368-bp fragment of a van cluster contained one open reading frame encoding a peptide with 83% amino acid identity to VanHD, and a second encoding a d-alanine-d-lactate ligase with 83 to 85% identity to VanD. The divergent glycopeptide resistance phenotype was designated VanD4.

Occurrence of extended-spectrum beta-lactamases in Enterobacteriaceae isolated from hospitalized patients in Curitiba, southern Brazil

Production of extended-spectrum beta-lactamases (ESBL) by enterobacteria is an important resistance mechanism against antimicrobial beta-lactamics. We tested 498 bacterial strains isolated from two tertiary-care teaching hospitals for ESBL production, using screening breakpoints for aztreonam and third generation cephalosporins, according to CLSI recommendations. Among these isolates, 155 were positive for the ESBL screening test, and 121 (78%) were confirmed by the clavulanic acid combination disk method. We found a high frequency of ESBL (24%) among Enterobacteriaceae, with a frequency of 57.4% for Klebsiella pneumoniae, 21.4% for Klebsiella oxytoca, and 7.2% for E. coli. In other members of Enterobacteriaceae, non-Klebsiella and non-E. coli, the prevalence was 21.6%. Ceftriaxone and cefotaxime showed a higher sensitivity in the screening test (99.2%) when compared to ceftazidime, aztreonam and cefpodoxime. However, cefotaxime/cefotaxime plus clavulanic acid showed a higher sensitivity in the confirmatory test (96.7%).

Early microbial colonization of cystic fibrosis patients identified by neonatal screening, with emphasis on Staphylococcus aureus.

OBJECTIVES To assess bacterial colonization prospectively in patients with cystic fibrosis identified by neonatal screening. To assess susceptibility to antimicrobials and to perform the molecular typing of Staphylococcus aureus strains isolated from the oropharynx of patients during the study. METHODS Twenty-five cystic fibrosis patients receiving regular treatment at the Cystic Fibrosis Outpatient Clinic of Hospital de Clínicas of Universidade Federal do Paraná, Brazil, were included in the study. All patients were identified by trypsin-like immunoreactivity and their diagnosis was confirmed by two or more sweat tests. Oropharyngeal swabs were collected and cultured according to routine methods; bacterial colonies were phenotypically identified and their susceptibility to antimicrobials was tested. S. aureus isolates were submitted to molecular typing using pulsed-field gel electrophoresis. RESULTS Out of 234 oropharyngeal swabs, S. aureus was the most frequently isolated strain (76% of patients, 42% of swabs), followed by Pseudomonas aeruginosa (36% of patients, 16% of swabs) and Haemophilus spp. (76% of patients; 19% of swabs). Seventy-three isolates were obtained from 19 patients colonized with S. aureus, of which 18 were oxacillin-resistant (24.6%), isolated from two patients, with the same electrophoretic profiles as that of the Brazilian clone. The remaining oxacillin-sensitive isolates were distributed into 18 electrophoretic profiles. CONCLUSION There was higher prevalence of S. aureus, with earlier isolation than other pathogens. Multi-sensitive isolates were distributed into different clones, characterizing non-transmissibility among community-acquired strains. The isolated oxacillin-resistant S. aureus showed identical electrophoretic profiles, probably acquired in hospital. P. aeruginosa was not so frequent in the studied population.

Colonização microbiana precoce de pacientes identificados por triagem neonatal para fibrose cística, com ênfase em Staphylococcus aureus

OBJETIVOS: Avaliar prospectivamente a colonizacao bacteriana de pacientes com fibrose cistica identificados por triagem neonatal. Avaliar a suscetibilidade a antimicrobianos e caracterizar molecularmente as cepas de Staphylococcus aureus isoladas da orofaringe dos pacientes no periodo do estudo. METODOS: Foram estudados 25 pacientes com fibrose cistica, identificados por tripsina imunorreativa e com diagnostico confirmado por duas ou mais provas de suor, atendidos regularmente no ambulatorio de fibrose cistica do Hospital de Clinicas da Universidade Federal do Parana. Foram coletadas amostras de orofaringe com swab e cultivadas por metodos rotineiros; as colonias bacterianas foram identificadas fenotipicamente e testadas quanto a suscetibilidade a antimicrobianos. Os isolados de S. aureus foram submetidos a tipagem molecular por eletroforese em campo pulsado. RESULTADOS: De um total de 234 amostras de orofaringe, S. aureus foi isolado em maior numero (76% dos pacientes, 42% das amostras), seguido de Pseudomonas aeruginosa (36% dos pacientes, 16% das amostras) e Haemophilus spp. (76% dos pacientes; 19% das amostras). Dos 19 pacientes colonizados com S. aureus, foram obtidos 73 isolados, 18 oxacilina-resistentes (24,6%), isolados de dois pacientes, com perfis eletroforeticos identicos ao do clone brasileiro. Os demais isolados oxacilina-sensiveis distribuiram-se entre 18 perfis eletroforeticos distintos. CONCLUSAO: Observou-se uma maior prevalencia de S. aureus, com isolamento mais precoce em relacao aos outros patogenos pesquisados. Os isolados multissensiveis distribuiram-se em clones distintos, caracterizando a nao transmissibilidade entre as cepas comunitarias. Os S. aureus resistentes a oxacilina isolados apresentaram perfis eletroforeticos identicos, provavelmente adquiridos no ambiente hospitalar. P. aeruginosa foi pouco frequente na populacao estudada.

Polyphasic characterisation of Burkholderia cepaciacomplex species isolated from children with cystic fibrosis

Cystic fibrosis (CF) patients with Burkholderia cepacia complex (Bcc) pulmonary infections have high morbidity and mortality. The aim of this study was to compare different methods for identification of Bcc species isolated from paediatric CF patients. Oropharyngeal swabs from children with CF were used to obtain isolates of Bcc samples to evaluate six different tests for strain identification. Conventional (CPT) and automatised (APT) phenotypic tests, polymerase chain reaction (PCR)-recA, restriction fragment length polymorphism-recA, recAsequencing, and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) were applied. Bacterial isolates were also tested for antimicrobial susceptibility. PCR-recA analysis showed that 36 out of the 54 isolates were Bcc. Kappa index data indicated almost perfect agreement between CPT and APT, CPT and PCR-recA, and APT and PCR-recA to identify Bcc, and MALDI-TOF and recAsequencing to identify Bcc species. The recAsequencing data and the MALDI-TOF data agreed in 97.2% of the isolates. Based on recA sequencing, the most common species identified were Burkholderia cenocepacia IIIA (33.4%),Burkholderia vietnamiensis (30.6%), B. cenocepaciaIIIB (27.8%), Burkholderia multivorans (5.5%), and B. cepacia (2.7%). MALDI-TOF proved to be a useful tool for identification of Bcc species obtained from CF patients, although it was not able to identify B. cenocepacia subtypes.

A Gardnerella vaginalis e as infecções do trato urinário

Urinary tract infections are among the most recurrent in human beings. They are caused by a wide variety of usual uropathogens, although they may be caused by some fastidious micro-organisms, such as Gardnerella vaginalis. It is a facultative anaerobe, found in the form of Gram-variable coccobacilli. It inhabits the vaginal mucosa and occasionally may cause urinary tract infections. The isolation may be performed on urine samples using CNA agar, incubated for 48-72 hours in atmosphere rich in CO2. The Gram examination of non-centrifuged urine may aid the microbiologist in identifying samples in which a fastidious bacterium is the causative agent, since the visualization of numerous epithelial cells, the absence of leukocytes and the presence of more than one morphological type suggest sample contamination. As studies show the Gardnerella vaginalis incidence among the causative agents of urinary tract infections, the isolation in urine cultures can not be overlooked. The clinical interpretation of the Gardnerella vaginalis growth is difficult to assess, thus being essential the information exchange between the clinical microbiology laboratory and medical staff in order to investigate the presence of signs and symptoms that may be associated with urinary tract infections.

Quando e como valorizar culturas de urina polimicrobianas no laboratório de microbiologia clínica

INTRODUCAO: Na maioria dos laboratorios de Microbiologia considera-se contaminacao uma cultura de urina com mais de um morfotipo colonial, ignorando-se o desenvolvimento ou solicitando-se novo material. Raramente o isolado e considerado significativo. OBJETIVOS: Com a finalidade de estudar as infeccoes urinarias polimicrobianas, no periodo de agosto de 2003 a janeiro de 2004, na cidade de Tubarao, Santa Catarina, foram selecionadas 117 amostras de urina de pacientes internados no Hospital Nossa Senhora da Conceicao, de ambos os sexos, com idades que variavam de 14 a 98 anos. METODOS: Realizou-se uma analise minuciosa dos prontuarios dos pacientes. Procedeu-se o Gram da gota de urina nao centrifugada e a cultura com alca calibrada de 1 ou 10 μl em agar CLED (cistina-lactose deficiente em eletrolitos). Todas as culturas foram repetidas com nova coleta de urina com supervisao direta. Os clinicos aguardaram a segunda coleta (confirmatoria) para iniciar a antibioticoterapia. Descartaram-se os pacientes que iniciaram a antibioticoterapia imediatamente apos a primeira coleta ou que estavam utilizando antimicrobianos. RESULTADOS: Obteve-se o total de seis (12,8%) culturas polimicrobianas confirmadas, em um universo de 47 amostras com crescimento bacteriano estudadas. Os resultados foram compativeis com as indicacoes clinicas. CONCLUSAO: E importante ressaltar a correlacao entre os achados laboratoriais e as indicacoes clinicas dos pacientes. Recomenda-se avaliar criteriosamente isolados polimicrobianos em amostras de urina, sejam ambulatoriais ou hospitalares.