Prevalence of Shiga Toxin-Producing and Enteropathogenic Escherichia coli in Wild and Pet Birds in Iran

ABStRACt The aim of this study was to investigate the prevalence of Shiga toxin-producing Escherichia coli (STEC) and enteropathogenic E. coli (EPEC) strains and to identify the stx gene types in wild captive and companion birds. In total,657 E. coli isolates from 219 birds belonging to 38 different species were investigated for the presence of STEC and EPEC strains. It was shown that five birds (2.28%) carried strains positive for one or more of the virulence factors investigated. The results indicated that 1.8% (n=4) and 0.45% (n=1) of the birds carried STEC and EPEC strains, respectively. All STEC strains harbored the stx2f and eae genes and this finding reveals the role of other birds, in addition to pigeons, as reservoirs of STEC. The only EPEC strain in this study was isolated from a Myna. Based on our knowledge, this is the first report of Stx2f-producing STEC in Geese, Duck and Lesser kestrel. In conclusion, the results indicate a low frequency of STEC carriage in wild and companion birds, and point out the need of additionally screening for the presence of stx2f in all the eae-harboring strains from birds

Whole-Genome Characterization and Strain Comparison of VT2f-Producing Escherichia coli Causing Hemolytic Uremic Syndrome.

Verotoxigenic Escherichia coli infections in humans cause disease ranging from uncomplicated intestinal illnesses to bloody diarrhea and systemic sequelae, such as hemolytic uremic syndrome (HUS). Previous research indicated that pigeons may be a reservoir for a population of verotoxigenic E. coli producing the VT2f variant. We used whole-genome sequencing to characterize a set of VT2f-producing E. coli strains from human patients with diarrhea or HUS and from healthy pigeons. We describe a phage conveying the vtx2f genes and provide evidence that the strains causing milder diarrheal disease may be transmitted to humans from pigeons. The strains causing HUS could derive from VT2f phage acquisition by E. coli strains with a virulence genes asset resembling that of typical HUS-associated verotoxigenic E. coli

Molecular detection and occurrence of vancomycin resistance genes (van A, B, C1, C2/C3) among Enterococcus species isolated from farm ostriches

Abstract Background Evaluating the prevalence of vancomycin resistance genes (van genes) in enterococcal isolates from food‐producing animals is an important public health issue because of the possibility of resistance genes spread to human. Objectives The present study aimed to determine the occurrence of vancomycin resistance genes among Enterococcus species obtained from ostrich faecal samples. Methods One hundred and twenty‐five faecal samples of apparently healthy ostriches from five different farms were investigated. Genes encoding vancomycin resistance were studied by multiplex‐PCR, and susceptibility to six antibiotics was evaluated by disk‐diffusion method. Results In total, 107 Enterococcus spp. isolates were obtained and confirmed by biochemical and molecular tests. Enterococcus faecium was the prevailing species (56 isolates of 107; 52.3%), followed by E. hirae (24 isolates; 22.4%) and E. gallinarum (12 isolates; 11.2%). Of the 107 recovered isolates, 44% harboured at least a type of van genes. vanA, vanC2/3 and vanC1 were identified in 34 (31.7%), 13 isolates (12.1%) and 4 (3.7%) isolates respectively. Additionally, four isolates (E. gallinarum, E. rafinosus) co‐harboured the the vanA and vanC1 or vanA and vanC2/3. Enterococcus faecium and Enterococcus hirae strains with the vanA genotype were the most frequent van‐carrying enterococci from ostrich faecal samples. Among van‐carrying enterococcal isolates, 23.4% were phenotypically resistant to vancomycin. This study revealed a relatively high prevalence (44%) of van‐carrying enterococci in ostrich faecal samples. Conclusions Results of the present study suggest that ostrich faeces could be considered as a reservoir of vancomycin resistance genes, especially vanA containing enterococci that could be potentially transferred to human through the food chain

Pathogenic potential of Shiga toxin-producing Escherichia coli strains of caprine origin: virulence genes, Shiga toxin subtypes, phylogenetic background and clonal relatedness

Abstract Background All over the world, Shiga toxin-producing Escherichia coli (STEC) are considered as important zoonotic pathogens. Eight serogroups have the greatest role in the outbreaks and diseases caused by STEC which include O26, O45, O103, O111, O113, O121, O145 and O157. Ruminants, especially cattle are the main reservoirs but the role of small ruminants in the epidemiology of human infections has not been thoroughly assessed in many countries. The objective of this research was to investigate the pathogenic potential of the STEC strains isolated from slaughtered goats. In this study, a total of 57 STEC strains were recovered from 450 goats and characterized by subtyping of stx genes, O-serogrouping, phylo-typing and DNA fingerprinting. Results Amongst 57 STEC strains isolated from goats, the prevalence of stx1 was significantly more than stx2 (98.2% vs. 24.5%; P ≤ 0.05), and 22.8% of strains harbored both stx1 and stx2 genes. Three (5.2%) isolates were characterized as EHEC, which carried both eae and stx genes. A total of five stx-subtypes were recognized namely: stx1c (94.7%), stx1a (53.7%), stx2d (21%), stx2c (17.5%), and stx2a (15.7%). In some parts of the world, these subtypes have been reported in relation with severe human infections. The stx subtypes predominantly occurred in four combinations, including stx1a/stx1c (35%), stx1c (31.5%), stx1c/stx2a/stx2c/stx2d (5.2%) and stx1c/stx2c/stx2d (%5.2%). In serogrouping, the majority of STECs from goats did not belong to the top 8 serogroups but two strains belonged to O113, which has been recognized as an important pathogenic STEC in Australia. Interestingly, none of stx + eae + isolates belonged to the tested serogroups. In phylo-typing the isolates mostly belonged to phylo-group B1 (82.4%), followed by phylo-group A (12.3%). STEC strains showed a substantial diversity in DNA fingerprinting; there were 24 unique ERIC-types (with a ≥95% similarity) among the isolates. Conclusions Despite the fact that the top 8 STEC serogroups were uncommon in caprine strains, the presence of highly pathogenic stx subtypes indicates that small ruminants and their products can be considered as an overlooked public health risk for humans, especially in developing countries which consume traditional products

Molecular investigation of Lawsonia intracellularis in diarrheic and healthy captive ostriches (Struthio camelus) in Iran

Lawsonia intracellularis is the causative agent of proliferative enteropathy (PE) in pigs, a disease of economic importance worldwide. The present study aimed to investigate the occurrence of L. intracellularis in ostriches using a sensitive and specific nested polymerase chain reaction (nested PCR). A total number of 112 fecal samples (64 healthy, 48 diarrheic) were collected from 11 ostrich farms located in four provinces in Iran (Semnan, Tehran, Gilan, Yazd). The results showed the presence of L. intracellularis in three diarrheic and four apparently healthy birds. The frequency of positive results was the same in both groups (6.25% healthy vs. 6.25% diarrheic). Although the results of this study did not reveal any relationship between this organism and diarrhea (P > 0.05), the molecular detection of L. intracellularis on a farm where birds were suffering from the typical clinical symptoms of PE highlights the need for evaluation of PE in ratites

Whole-Genome Characterization and Strain Comparison of VT2f-Producing Escherichia coli Causing Hemolytic Uremic Syndrome.

Verotoxigenic Escherichia coli infections in humans cause disease ranging from uncomplicated intestinal illnesses to bloody diarrhea and systemic sequelae, such as hemolytic uremic syndrome (HUS). Previous research indicated that pigeons may be a reservoir for a population of verotoxigenic E. coli producing the VT2f variant. We used whole-genome sequencing to characterize a set of VT2f-producing E. coli strains from human patients with diarrhea or HUS and from healthy pigeons. We describe a phage conveying the vtx2f genes and provide evidence that the strains causing milder diarrheal disease may be transmitted to humans from pigeons. The strains causing HUS could derive from VT2f phage acquisition by E. coli strains with a virulence genes asset resembling that of typical HUS-associated verotoxigenic E. coli