Diarrhoeagenic Escherichia coli (DEC) is a leading cause of infectious diarrhoea worldwide. In recent years, Escherichia albertii has also been implicated as a cause of human enteric diseases. This study describes the occurrence of E. coli pathotypes and serotypes associated with enteric illness and haemolytic uremic syndrome (HUS) isolated in Brazil from 2011 to 2016. Pathotypes isolated included enteropathogenic E. coli (EPEC), enteroaggregative E. coli (EAEC), enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC) and Shiga toxin-producing E. coli (STEC). PCR of stool enrichments for DEC pathotypes was employed, and E. albertii was also sought. O:H serotyping was performed on all DEC isolates. A total of 683 DEC and 10 E. albertii strains were isolated from 5047 clinical samples. The frequencies of DEC pathotypes were 52.6% (359/683) for EPEC, 32.5% for EAEC, 6.3% for ETEC, 4.4% for EIEC and 4.2% for STEC. DEC strains occurred in patients from 3 months to 96 years old, but EPEC, EAEC and STEC were most prevalent among children. Both typical and atypical isolates of EPEC and EAEC were recovered and presented great serotype heterogeneity. HUS cases were only associated with STEC serotype O157:H7. Two E. albertii isolates belonged to serogroup O113 and one had the stx2f gene. The higher prevalence of atypical EPEC in relation to EAEC in community-acquired diarrhoea in Brazil suggests a shift in the trend of DEC pathotypes circulation as previously EAEC predominated. This is the first report of E. albertii isolation from active surveillance. These results highlight the need of continuing DEC and E. albertii surveillance, as a mean to detect changes in the pattern of pathotypes and serotypes circulation and provide useful information for intervention and control strategies.
Enteropathogenic Escherichia coli (EPEC) are important agents of diarrhoea in industrialized as well as developing countries, such as Brazil. The hallmark of EPEC pathogenesis is the establishment of attaching and effacing lesions in enterocytes, in which pedestal-like structures are formed underneath adherent bacteria. EPEC are divided into two subgroups, typical (tEPEC) and atypical (aEPEC), based on the presence of the EPEC adherence factor plasmid in tEPEC and its absence in aEPEC. This study was designed to characterize 82 aEPEC isolates obtained from stool samples of diarrhoeic patients during 2012 and 2013 in Brazil. The majority of the aEPEC were assigned to the phylo-group B1 (48.8 %), and intimin subtypes θ (20.7 %), β1 (9.7 %) and λ (9.7 %) were the most prevalent among the isolates. The nleB and nleE genes were concomitantly detected in 32.9 % of the isolates, demonstrating the occurrence of the pathogenicity island O122 among them. The O157-plasmid genes (ehxA and/or espP) were detected in 7.3 % of the isolates, suggesting that some aEPEC could be derived from Shiga-toxin-producing E. coli that lost the stx genes while trafficking in the host. PFGE of 14 aEPEC of serotypes O2 : H16, O33 : H34, O39 : H9, O108 : H- and ONT : H19 isolated from five distinct outbreaks showed serotype-specific PFGE clusters, indicating a high degree of similarity among the isolates from the same event, thus highlighting these serotypes as potential aetiologic agents of diarrhoeal outbreaks in Brazil.
We sought to determine the resistance phenotypes for erythromycin and clindamycin and the mechanisms implicated in 93 Streptococcus agalactiae isolates recovered from healthy pregnant women. Susceptibility testing for erythromycin, clindamycin, penicillin, cefotaxime, vancomycin, quinupristin-dalfopristin, choramphenicol, ofloxacin, and meropenen was carried out by disc-diffusion test, and the E-test was also applied for erythromycin and clindamycin. The constitutive MLS(B) resistance (cMLS(B)) and inducible MLS(B) resistance (iMLS(B)) phenotypes, respectively, as well as the M resistance phenotype were determined by the erythromycin-clindamycin double-disc test. The presence of ermA, ermB, ermC, msrA, and mef(A/E) macrolide resistance genes was studied by PCR. Resistance to erythromycin and clindamycin was found in 15% and 9.6% of the isolates, respectively. The resistance phenotypes detected among the 14 erythromycin-resistant isolates were as follows (number of isolates): cMLS(B) (9), iMLS(B) (3), and M (2). The MICs for erythromycin and clindamycin were as follows: cMLS(B) isolates (128-256 and >or=32 mg/L, respectively), iMLS(B) isolates (16-256 and 1 mg/L), and M isolates (2-8 and 1 mg/L). The following combination of genes were detected among isolates with cMLS(B) or iMLS(B) phenotypes: erm(B) (6 isolates), ermA + ermTR (3), ermA + ermB + ermTR (1), and none of these genes (2). The two isolates with M phenotype harbored the mef(A/E), and msrA gene was also found in one of them.
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