Biochemical methods employed to classify bacterial species have limitations and may have contributed to the taxonomic complexity recently reported for the genus Klebsiella. The objective of the present study was to apply a simple biochemical test panel to classify a collection of human Klebsiella isolates. We found that with only three additional tests, it is possible to place most isolates in a defined species. Analysis of a 512-bp sequence of the rpoB gene was used as the reference. A total of 16 conventional and 4 supplementary tests were used to evaluate 122 recent isolates identified as Klebsiella from 120 patients, isolated at the clinical laboratory of a university hospital in Minas Gerais, Brazil. Of these, 102 (84%) isolates were identified as Klebsiella pneumoniae or Klebsiella variicola, 19 (15%) as Klebsiella oxytoca, and 1 (1%) as Raoultella planticola. Enterobacterial repetitive intergenic consensus-PCR typing revealed a diversity of genotypes. rpoB gene sequencing confirmed the phenotypic identification and detected five K. variicola isolates among the K. pneumoniae/K. variicola group. Three additional tests that include growth at 10°C and histamine and D-melezitose assimilation should be considered essential tests for the typing of Klebsiella isolates.

Production of extended-spectrum beta-lactamases (ESBLs) has been reported in virtually all species of Enterobacteriaceae, which greatly complicates the therapy for infections caused by these organisms. However, the frequency of isolates producing AmpC beta-lactamases, especially plasmid-mediated AmpC (pAmpC), is largely unknown. These beta-lactamases confer resistance to extended-spectrum cephalosporins and aztreonam, a multidrug-resistant (MDR) profile. The aim of the present study was to determine the occurrence of ESBL and pAmpC beta-lactamases in a hospital where MDR enterobacterial isolates recently emerged. A total of 123 consecutive enterobacterial isolates obtained from 112 patients at a university hospital in Rio de Janeiro, Brazil, during March to June 2001 were included in the study. ESBL was detected by the addition of clavulanate to cephalosporin containing disks and by double diffusion. AmpC production was evaluated by a modified tridimensional test and a modified Hodge test. The presence of plasmid-mediated ampC beta-lactamase genes was evaluated by multiplex polymerase chain reaction. Sixty-five (53%) of 123 enterobacterial isolates were MDR obtained from 56 patients. ESBL production was detected in 35 isolates; 5 clonal Escherichia coli isolates exhibited high levels of chromosomal AmpC and ESBL production. However, no isolates contained pAmpC genes. Infection or colonization by MDR enterobacteria was not associated with any predominant resistant clones. A large proportion of hospital infections caused by ESBL-producing enterobacteria identified during the study period were due to sporadic infections rather than undetected outbreaks. This observation emphasizes the need to improve our detection methods for ESBL- and AmpC-producing organisms in hospitals where extended-spectrum cephalosporins are in wide use.

Acinetobacter soli is a new bacterial species described from forest soil. Five cases of bloodstream infection caused by A. soli clonal isolates are reported here for the first time. The patients were neonates admitted to an intensive care unit. This is a new neonatal pathogen with the potential to cause outbreaks.

These findings suggest a common source of infection for all patients and reinforce the hypotheses of spread of M. massiliense BRA100 in Brazilian hospital surgical environment in recent years.

The epidemiology of urinary tract infections (UTI) by Staphylococcus saprophyticus has not been fully characterised and strain typing methods have not been validated for this agent. To evaluate whether epidemiological relationships exist between clusters of pulsed field gel-electrophoresis (PFGE) genotypes of S. saprophyticus from community-acquired UTI, a cross-sectional surveillance study was conducted in the city of Rio de Janeiro, Brazil. In total, 32 (16%) female patients attending two walk-in clinics were culture-positive for S. saprophyticus. Five PFGE clusters were defined and evaluated against epidemiological data. The PFGE clusters were grouped in time, suggesting the existence of community point sources of S. saprophyticus. From these point sources, S. saprophyticus strains may spread among individuals.

Aims:  The main aim of this study was to analyse the genetic relationship amongst 46 Staphylococcus aureus Bac+ strains isolated in Brazil from 12 geographically distant dairy herds, including 34 isolates that produce the antimicrobial peptide aureocin A70. Methods and Results:  The comparison of 46 Staph. aureus Bac+ strains was performed by pulsed‐field gel electrophoresis (PFGE). Thirteen different pulsotypes were identified, and the subtype A1 was the most prevalent one. Nine strains belong to pulsotype F, the second most prevalent and mostly confined to a single herd. The PFGE patterns of the 34 Staph. aureus aureocin A70‐producers, isolated in Brazil, were also compared with those of strains isolated from bovine mastitis cases in Argentina and revealed that these strains are not genetically related. Conclusions:  Although a previous study has suggested that a prevalent pulsotype of aureocin A70‐producer Staph. aureus involved in bovine mastitis is disseminated in Argentina, this does not occur in Brazil. Additionally, it was possible to demonstrate that closely related staphylococcal strains can produce distinct staphylococcins. Significance and Impact of the Study:  This study corroborates the hypothesis of horizontal gene transfer of aureocin A70 genes amongst distinct staphylococcal strains involved in bovine mastitis, giving them a selective advantage when colonizing the mammary glands.

Escherichia coli clones ST131, ST69, ST95 and ST73 are frequent causes of urinary tract infections (UTI) and bloodstream infections. Specific clones and virulence profiles of E. coli causing UTI in men has been rarely described. The aim of this study was to characterize patient and clonal characteristics of community-acquired UTI caused by E. coli in men (n=12) and women (n=127) in Rio de Janeiro, Brazil, complementing a previous work. We characterized isolates in phylogenetic groups, ERIC2-PCR and PFGE types, MLST, genome similarity and virulence gene-profiles. UTI from men were more frequently caused by phylogenetic group B2 isolates (83% vs 42%, respectively, p 0.01), a group with significantly higher virulence scores compared with women. ST73 was the predominant clone in men (50%) and the second most frequent in women (12%), with the highest virulence score (mean and median=9) among other clones. ST73 gnomes formed at least six clusters. E. coli from men carried significantly higher numbers of virulence genes, such as sfa/focDE (67% vs 27%), hlyA (58% vs 24%), cnf 1 (58% vs 16%), fyuA (100% vs 82%) and MalX (92% vs 44%), compared with isolates from women. These data suggest the predominance and spread of ST73 isolates likely relates to an abundance of virulence determinants.

No abstract