Vancomycin-dependent Enterococcus faecium vanA: characterization of the first case isolated in a university hospital in Brazil

In this study, we report the characterization of a strain of Enterococcus faecium vanA, which grows only in the presence of vancomycin (VDEfm-UEL). The bacterium was isolated from the feces of a female patient who had undergone surgical treatment of Reinke’s edema and was receiving intravenous vancomycin therapy for infection with methicillin/oxacillin-resistant Staphylococcus aureus, a postoperative complication. Antimicrobial dependence was further confirmed by the vancomycin E-test. VDEfm-UEL was also shown to be resistant to ampicillin, ciprofloxacin, chloramphenicol, erythromycin, levofloxacin, penicillin, rifampicin, and teicoplanin. The putative virulence genes efaA, gelE and esp were detected by PCR. The ddl gene from VDEfm-UEL was cloned and sequenced. Vancomycin dependence seems to be associated with the insertion of a nucleotide in that sequence, which results in a frame-shift mutation, introducing a premature stop codon. This is the first report of vancomycin-dependent E. faecium isolation in a university hospital in Brazil.

Atypical phenotypic characteristics of klebsiella pneumoniae isolates from an outbreak in a neonatal intensive care unit in Brazil

Extended-spectrum beta-Lactamase-producing (ESBL) Klebsiella sp.isolates from an outbreak in a Neonatal Intensive Care Unit (NICU) at a teaching hospital in Londrina, Paraná State, Brazil, presented atypical phenotypic characteristics that hampered their identification and the distinction between Klebsiella and Enterobacter species. Ten isolates were identified as K. pneumoniae due to negative reactions for motility and inducible beta-lactamase test (ESBL and AmpC) despite being positive for ornithyne descarboxilase. These isolates were genotyped by ribotyping and polymerase chain reaction (PCR) with repetitive extragenic palindromic sequences (REP). Ribotyping by means of an automated instrument and EcoRI and Pvu II as restriction enzymes resulted indetection of K. pneumoniae subspecie pneumoniae RIBO1 222-36-S-5 ribotype. Typing by REP-PCR showed that the 17 isolates from the outbreak were highly similar, belonging to one cluster with 100 percent of similarity, and that they presented more than 70 percent of similarity with K. pneumoniae ATCC 13883 and ATCC 10031, and 25 percent of similarity with E. aerogenes CDC 1680. In conclusion, the isolates of the outbreak were identified as Klebsiella pneumoniae, despite presenting ornithyne descarboxilase enzyme, which is an atypical characteristic of this Klebsiella species.

Isolados de Klebsiella sp. produtora de beta-lactamase de espectro estendido (ESBL), responsável por um surto na Unidade Neonatal de Terapia Intensiva (UNTI) do Hospital Universitário de Londrina, Paraná, Brasil apresentaram características fenotípicas atípicas que dificultaram sua identificação e a diferenciação entre as espécies Klebsiella pneumoniae e Enterobacter aerogenes. Dez isolados foram identificados como K. pneumoniae devido às reações negativas para motilidade e produção de enzimas beta-lactamases (ESBL e AmpC). Embora apresentassem teste positivo para ornitina descarboxilase. Estes isolados foram genotipados por ribotipagem e por reação em cadeia da polimerase (PCR) com oligonucleotídeos para "repetitive extragenic palindromic sequences" (REP). A ribotipagem com as enzimas de restrição EcoRI e Pvu II detectou o ribotipo de K. pneumoniae subespécie pneumoniae RIBO1 222-36-S-5. A técnica de REP-PCR mostrou que os isolados do surto foram similares, pertencentes a um grupo com 100 por cento de similaridade, e apresentaram mais de 70 por cento de similaridade com amostras padrão de K. pneumoniae (ATCC 13883 e 10031), e 25 por cento de similaridade com E. aerogenes CDC 1680. Concluindo, os isolados do surto da NICU mostraram se geneticamente relacionados e foram identificados como Klebsiella pneumoniae, embora apresentassem ornitina descarboxilase, característica atípica para esta espécie de Klebsiella.

Frequency of pap and pil operons in Escherichia coli strains associated with urinary infections

Strains of E. coli isolated from patients with urinary tract infection were examined for P and type 1 adhesin production by colony hybridization with pap and pil operons. The P pili probe detected 45 (46.4 per cent) of the total of 97 strains studied and the type 1 pili probe detected 83 (85.6 per cent). The pap operon was detected in 39 (53.4 per cent) of 73 strains isolated from urine of patients with urinary disease and in 6 (25.0 per cent) of 24 strains isolated from feces of healthy individuals employed as controls (P = 0.029), and the pil operon was detected in 67 (91.8 per cent) of the urinary strains and in 16 (66.6 per cent) of the fecal strains (P = 0.007). Our data did not show significant differences in frequency of P pili among isolates from pyelonephritis (78.5 per cent), cystitis (45.8 per cent) and asymptomatic bacteriuria (54.5 per cent). Type 1 pili were not associated with the different types of infection; the frequency of these pili was 100 per cent in pyelonephritis and in asymptomatic bacteriuria, and 87.5 per cent in cystitis. The incidence of pap operon in strains isolated from pyelonephritis and from asymptomatic bacteriuria was higher in 11-to 40-year old women. These data show a high frequency of pap and pil operons among uropathogenic strains of E. coli, which seems to be an important factor in the development of urinary infection.

Virulence factors of Eschericha coli in urinary isolates

Escherichia coli strains isolated from 100 urine samples taken from patients with urinary tract infections (UTI) and from 20 normal fecal (NF) samples were examined for serum resistance, mannose-resistant hemagglutination of human erythrocytes (MRHA) and for production of aerobactin, hemolysis and colicin. Among the UTI E. coli strains, 79% produced aerobactin, 69% showed serum resistance, 44% produced MRHA, 32% were beta-hemolytic and 22% were colicinogenic. A greater proportion of UTI E. coli strains produced aerobactin, colicin V, beta-hemolysis and MRHA when compared to NF strains. Production of MR hemagglutins was significant correlated with that of aerobactin and hemolysin. These results suggest that the presence of aerobactin may be a significant etiological factor in UTI, and that the production of MR adhesins and of hemolysin also might contribute to the virulence of these strains