Abstract
Background and Aim: Wild birds can carry a number of potential human and animal pathogens. These birds can intrude into human habitats giving the opportunity to transmission of such infection. Therefore, the current study was designed to investigate the role of crows and water fowls as vectors of Salmonella and Listeria monocytogenes and to compare cultivation methods with direct PCR for detection of infection.
Materials and Methods: A total of 200 fecal dropping samples were collected. Salmonella was cultivated by three step method (on universal pre-enrichment broth (UPB), Rappaport-Vassiliadis broth (R-V) and xylose lysine desoxycholate agar (XLD). The recovered isolates were characterized by biotyping, serotyping and PCR detection of enterotoxin (stn) gene. The antibiogram pattern of isolates against a panel of 8 antibiotics was recorded.
L. monocytogenes was cultivated on UPB, then on listeria Oxford agar and listeria CHROMagar. The recovered isolates were characterized by biotyping and PCR detection of listeriolysin (hyl A) gene.
Direct PCR detection of the two pathogens was carried out by targeting stn and hyl A genes.
Results: The percentages of Salmonella infection in crows and water fowls were (10 and 20), respectively. The most frequently recovered serovars were typhimurium, potengi, enteritidis and kentucky. Antimicrobial susceptibility analysis of Salmonella isolates showed that the resistance rates for gentamycin was (92%), amoxycycline (88%) and cefixime (60%). Resistance to 8 antibiotics was recorded in (60%, 15/25) of Salmonella isolates.
The percentages of L. monocytogenes infection in crows and water fowls were (1.3 and 2), respectively.
Direct PCR applied to UPB revealed that (12% and 3%) of samples were positive for Salmonella and Listeria monocytogenes, respectively and there was no significant difference between direct PCR and cultivation method for detection of infection.
Conclusion: The present findings indicate that wild birds can harbour zoonotic enteric pathogens and this necessitates monitoring the epidemiologic status of these pathogens among wild birds and humans and applying the appropriate protective measures to prevent the spread of infection.
Key words: Antibiotic susceptibility, crows, hylA and stn genes, Listeria monocytogenes, Salmonella, water fowls
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