ABSTRACT
The present study reported the first serotyping (O:H typing) data documented in Shiga toxin-producing Escherichia coli (STEC) strains of animal origin in Iran in isolates recovered between 2008 to 2016. A total number of 75 STEC strains previously isolated from fecal samples of cattle, sheep, goats, pigeons, humans, and deer were assessed by different polymerase chain reaction (PCR) assays detecting the major virulence genes of STEC and phylogroups. Then, the strains were tested for the 16 important O-groups by PCR. Finally, twenty strains were selected for H-genotyping by PCR plus sequencing. The predominant serogroup was O113 which was detected in nine isolates (five cattle, 55.50%; two goats, 22.20%; two red deer, 22.20%) followed by O26 (3/3, 100%) in cattle, O111 (3/3, 100%) in cattle, O5 (3/3, 100%) in sheep, O63 (1/1, 100%) in pigeon, O75 (2/2, 100%) in pigeons, and O128 in goats (2/3, 66.60%) and pigeon (1/3, 33.30%). The most important recognized serotypes were O113:H21 in cattle (2/3) and goat (1/3), O113:H4 in red deer (1/1), O111:H8 in calves (2/2), O26:H11 in calve (1/1), O128:H2 in goats (2/3) and pigeon (1/3), and O5:H19 in sheep (3/3). One cattle strain carrying stx1, stx2, eae, and Ehly genes belonged to O26:H29 serotype. Most strains with determined O-groups were from the bovine source that highlighted the importance of cattle as reservoirs of potentially pathogenic serovars. The present study suggested that the top seven non-O157 serogroups should be assessed along with O157 in all future research and clinical diagnostics of STEC in Iran.
ABSTRACT
PURPOSE: Enteropathogens are frequently associated with diarrheal disease. Knowledge of their etiology and epidemiology is essential for the prevention and control of the sickness. This study describes the microbiological and epidemiological features of diarrheal disease in 197 symptomatic and 223 asymptomatic under-five-year-old children from southeastern Brazil, between January 2015 and September 2016. METHODS: Isolation of Escherichia coli, Salmonella, Shigella and Campylobacter was realized by culture. E. coli strains were screened by multiplex PCR, PFGE and O:H serotyping. Antimicrobial susceptibility testing was also performed. RESULTS: Most of the 127 enteropathogens isolated were diarrheagenic E. coli (96.1 %), with predominance of several serotypes of enteropathogenic E. coli (EPEC) and enteroaggregative E. coli (EAEC). Age, sex, rotavirus vaccination, recent use of antibiotics and previous contact with pets, were factors that revealed no significant effects on the probability of infection by the predominant pathogens. Even so, higher incomes could be related to a lesser chance of testing positive for EPEC. Evidence of possible EAEC clonal spread was detected, as well as genetic similarity among strains from both symptomatic and asymptomatic children. Resistance to antimicrobial agents was more pronounced among EAEC than EPEC. CONCLUSION: The occurrence of genetically similar diarrheagenic E. coli in both groups of children, likewise resistant to these agents, underscores the importance of establishing strategies for the prevention of outbreaks, especially among low-income households.
