Escherichia coli O157:H7 is a highly virulent human pathogen with severe consequences following infection, which claims many lives worldwide. A suggested method for controlling this bacterium is the ...competitive elimination through using probiotic bacteria that prevent its colonization. Some nonpathogenic E. coli strains that produce antibacterial colicins are among these probiotic bacteria. We aimed to isolate and characterize the colicinogenic E. coli strains from diarrheic and healthy sheep that inhibit E. coli O157:H7, which could be used as possible probiotic sources. A total of 292 E. coli isolates (146 from each diarrheic and healthy sheep) were screened for the presence of colicin and virulence genes. The phylogenetic group/subgroup determination was performed by PCR. In vitro evaluation of inhibitory effect of colicinogenic isolates on E. coli O157:H7 was done phenotypically.
The frequency of diarrhea associated colicinogenic E. coli isolates was significantly higher than those isolated from healthy sheep. An association between ETEC and the genes coding for colicin-V & colicin-Iab in diarrheic E. coli isolates was observed. Moreover, there was an association between ipaH and Colicin-V encoding genes. Furthermore, E. coli isolates showing bacteriocinogeny while possessing no virulence genes had a frequency of 97.67 and 11.94% in healthy and diarrheic isolates, respectively. Of these strains, five isolates (3.42%) from diarrheic and twenty-five isolates (17.12%) from healthy sheep inhibited O157:H7 strain. Additionally, colicin E1 and colicin Iab genes were more prevalent in B1 phylogroup.
These results signified that healthy sheep could be considered as a potential source for anti-O175:H7 bacterial isolates.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Urinary tract infection (UTI) is one of the most prevalent infectious diseases with worldwide health threatening. Antimicrobial resistant strains of Escherichia coli (E. coli) are a common cause of ...UTI which were identified as a treatment challenge. This study aimed to assay the prevalence of common β-lactam resistance genes including bla
, bla
, bla
and bla
and phenotypic resistance to commonly used β-lactam and fluoroquinolone antibiotics in UTIs. These factors were evaluated in various phylogenetic groups (phylotypes) of E. coli isolates. Real-time PCR was applied to detect β-lactam resistance genes and conventional PCR was used to determine the phylotypes. Phenotypic resistance against β-lactams (ceftazidime, cefotaxime, aztreonam and ceftriaxone) and fluoroquinolones (ciprofloxacin) were identified by the disc diffusion technique. The ability of extended spectrum β-lactamases (ESBLs) production in E. coli isolates was detected using the combined disc diffusion method.
The prevalence of resistance genes were 89.6% for bla
, 44.3% for bla
, 6.6% for bla
and 0.9% for bla
. The two high prevalent phylotypes were B2 (29.2%) and D (17.9%) followed by E (14.1%), F (9.4%), C (6.6%) and 10.3% of isolates were unknown in phylotyping. Disc diffusion results showed high prevalence of antibiotic resistance to cefotaxime (88.6%), aztreonam (83%), ceftireaxon (77.3%), ceftazidime (76.4%) and ciprofloxacin (55.6%). Totally, 52.8% of isolates were found as phenotypical ESBL-producers.
This study's results confirmed an explosion of antibiotic resistance amongst E. coli isolates from UTI against β-lactams and fluoroquinolones. Findings explain the necessity of deep changes in quantity and quality of drug resistance diagnosis and antibiotic therapy strategies. More studies are suggested to better and confident evaluations.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Two hundred and four Escherichia coli strains were isolated from external and visceral cavity surfaces of 102 slaughtered broiler carcasses. The isolates were screened to determine the phylogenetic ...background and presence of Shiga toxins (stx1, stx2), intimin (eae) and beta-lactamase (blaTEM, blaSHV) genes. Phylotyping results revealed that the E. coli isolates segregated in four phylogenetic groups A (56.86%), B1 (19.12%), B2 (4.90%) and D (19.12%). PCR assays revealed that 13 isolates (6.37%) from 12 carcasses were positive for eae (12 isolates) and/or stx2 (2) genes. The eae positive isolates belonged to phylogenetic groups A (A0, A1), B1, B2 (B22) and D (D2). Two stx2 positive and seven eae positive isolates were recovered from visceral cavity surface, whereas only 5 eae positive isolates were from the external surface of the carcasses. On the other hand, thirty one E. coli strains isolated from visceral cavity and external surface of 26 carcasses carried the blaTEM (27) and blaSHV (4) genes and belonged to different phylo-groups. This study suggests that broiler carcasses could be considered as an important source of EPEC and STEC pathotypes in southeast of Iran; as well as the examined antibiotic resistance genes, which were carried by some isolates and could be transferred to pathogens through the food chain.
•Broiler carcasses can be considered as a source of EPEC & STEC pathotypes.•Thirty one E. coli isolates possessed the beta-lactamase genes.•The positive isolates belonged to different phylo-group/subgroups.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Nomadic populations do not have permanent settlements as they move their livestock between grazing areas in different seasons; such movements may have great impact on dissemination of food-borne ...pathogens in various regions. The aim of this study was to characterize Shiga toxin-producing
Escherichia coli
(STEC) strains as a food-borne pathogen in sheep and goats of Bakhtiari pastoral tribe in Iran. In the present study, 72 fecal samples were obtained from 26 sheep and 46 goats. First, all recovered
E. coli
isolates were screened for
stx
gene. After detection of
stx
-positive isolates, the virulence genes including
stx1
,
stx2
,
eae
,
ehly
,
saa
,
astA
,
subAB
,
terD
, and the genetic markers of O Island 57 (Z2098 and Z2099) were investigated. Also fifteen important STEC O-serogroups were determined using PCR assays. Results showed that 27 animals (27/72; 37.5%) carried STEC strains including 16/26 (61.6%) sheep and 11/46 (23.9%) goats. All STECs were
eae
-negative but 81.4% (22/27) were positive for
saa
. The most prevalent virulence profile was
stx1
/
stx2
/
ehly
/
saa
/
subAB
(37%; 10/27). Most STECs (24/27) were positive for at least one of the selected OI-57 markers. The O91 (
n
= 6), O5 (
n
= 3), O113 (
n
= 1), O128 (
n
= 1), and O104 (
n
= 1) were the detected O-serogroups in this study. It is concluded that such moving animal populations could have public health concerns which have to be addressed in the future.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
species (spp) are the most prevalent zoonotic pathogens that cause outbreaks of gastroenteritis worldwide. Therefore evaluation of the profile of antibiotic resistance, virulence factors, and plasmid ...replicon types in these bacteria is necessary to control and prevent the spread of potentially pathogenic and drug-resistant strains.
This study was performed on 39
spp. The antibacterial susceptibility of isolates to various antibiotic agents was determined using disk diffusion test. β-lactamases (
) including ESBLs, AmpC, MBLs, and virulence genes were detected by PCR methods. Plasmid incompatibility groups among the isolates were identified using PCR-based replicon typing (PBRT).
The most prevalent virulent gene was
(84.6%).
, and
were identified in 79.4% (n=31), 69.2% (n=27), and 2.5% (n=1) of the isolates, respectively. The antibiotic susceptibility testing showed that 30.7% of the isolates were ESBL-producing.
(41%; n=16) was the most frequent β-lactamase gene among the isolates followed by
(15.4%; n=6),
(7.7%; n=3), and
(1.5%; n=1). Six different plasmid replicon types, including IncP (n=9; 23%), IncFIC (n=3; 7.70%), IncY (n=3; 7.70%), IncI1-Iγ (n=2; 5.12%), IncFIIAs (n=1; 2.56%), and IncN (n=1; 2.56%) were observed among the isolates.
Our study showed the emergence of carbapenem-resistant and
among
spp. for the first time in Kerman, Iran. Since
spp. plays an important role in the transmission of resistance genes in livestock and humans in the food chains, so more stringent control policies are recommended to prevent the circulation of drug-resistant and potentially pathogenic strains from animals to humans.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Intestinal pathotypes of
belong to the companion animals may poses potential risk to public health following zoonotic transmission. Therefore, this study was proposed to determine the virulence genes ...associated to diarrheagenic
strains isolated from healthy pet dogs and their owners in the southeast of Iran, Kerman province.
Totally 168
isolates were collected from 49 healthy household dogs and their owners. Seventy isolates were obtained from non-pet owners as control group. Presence or absence of the virulence genes including
and
were screened by conventional polymerase chain reaction (PCR) and dissemination pattern of the genes were studied among the various hosts.
PCR examinations showed that the most frequent virulence gene was
(6.1%) in dogs followed by
in dog owners (6.1%) and in controls (8.6%). The most frequent pathotypes in dogs, their owners and controls were EIEC (6.1%), EHEC (4.08%) and EPEC (8.5%), respectively. In one of studied houses, both of dog and its owner harbored
strains with same virulence profile
and pathotype (EHEC).
These results collectively indicate that healthy household dogs probably are the mild reservoir of potential virulent
strains with possible active transmission to their contact owner. However, even non-pet owners seemed to be a notable source of intestinal pathotypes, especially EPEC, for their environment. Transmission of
pathotypes may occurs by direct contact with the reservoirs or ingestion of contaminated food. These pathotypes are potentially virulent and creates public health hazards. Further studies are needed for better understanding of dissemination mechanisms of
pathotypes among humans and their pets.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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.
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.
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.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background: Diarrheagenic Escherichia coli (DEC) is a common enteric pathogen that causes a wide spectrum of gastrointestinal infections, particularly in developing countries. This is a systematic ...review and meta-analysis to determine the prevalence of DEC in various geographical regions in Iran. Materials and Methods: English (PubMed, Web of Science, Scopus, Embase, Cochrane Library, and Google Scholar) and Persian (IranMedex, SID, Magiran, and Iran Doc) databases were comprehensively searched from January 1990 to April 2017. Study selection and data extraction were performed by two independent reviewers. After assessing heterogeneity among studies, a random effects model was applied to estimate pooled prevalence. Data analyses were done with the Stata software (version 12.0). This meta-analysis was registered with PROSPERO, number CRD42017070411. Results: A total of 73 studies with 18068 isolates were eligible for inclusion within the meta-analysis. The results of random effects model showed that the most prevalent DEC pathotypes were enterotoxigenic E. coli (ETEC) (16%; 95% confidence interval CI: 11%-23%), enteroaggregative E. coli (11%; 95% CI: 8%-15%), atypical enteropathogenic E. coli (EPEC) (11%; 95% CI: 8%-14%), Shiga toxin-producing E. coli (9%; 95% CI: 6%-13%), diffuse adherent E. coli (6%; 95% CI: 6%-12%), enteroinvasive E. coli (4%; 95% CI: 2%-6%), and typical EPEC (3%; 95% CI: 1%-5%). Conclusion: This study showed that DEC infections in the Iranian population have low frequency. Our data suggest that the ETEC pathotype can be regarded as one of the most important etiological agents of diarrhea in this country. However, the prevalence of DEC pathotypes is diverse in different regions of Iran.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Transmission of antimicrobial resistant and virulent Escherichia coli (E. coli) from animal to human has been considered as a public health concern. This study aimed to determine the phylogenetic ...background and prevalence of diarrheagenic E. coli and antimicrobial resistance in healthy riding-horses in Iran. In this research, the genes related to six main pathotypes of E. coli were screened. Also, genotypic and phenotypic antimicrobial resistance against commonly used antibiotics were studied, then phylo-grouping was performed on all the isolates.
Out of 65 analyzed isolates, 29.23 % (n = 19) were determined as STEC and 6.15 % (n = 4) as potential EPEC. The most prevalent antimicrobial resistance phenotypes were against amoxicillin/clavulanic acid (46.2 %) and ceftriaxone (38.5 %). bla
was the most detected resistance gene (98.4 %) among the isolates and 26.15 % of the E. coli isolates were determined as multi-drug resistant (MDR). Three phylo-types including B1 (76.92 %), A (13.85 %) and D (3.08 %) were detected among the isolates.
Due to the close interaction of horses and humans, these findings would place emphasis on the pathogenic and zoonotic potential of the equine strains and may help to design antimicrobial resistance stewardship programs to control the dissemination of virulent and multi-drug resistant E. coli strains in the community.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background: Urinary tract infection (UTI) is one of the most commonly encountered diseases in clinical settings and uropathogenic Escherichia coli (UPEC) is the major causative pathogen of UTI. The ...increase of antibiotic resistance among isolates of E. coli has become a main concern worldwide. The purposes of this study were to determine the phylogenetic background, prevalence and characterize of extended-spectrum β-lactamases and metallo-β-Lactamase produced by E. coli from UTIs.Materials and Methods: Two hundred and sixteen E. coli isolates were isolated from UTI. The isolates were screened to determine the phylogenetic background and prevalence of CTX-M-15, PER, VEB, IMP and VIM genes by PCR. The antimicrobial susceptibility of isolates was determined by disk diffusion and broth micro-dilution methods. The isolates were screened using a double-disc synergy test.Results: Phylotyping of isolates revealed that isolates segregated in phylo-groups A (40.74%), B1 (7.87%), B2 (18.05%) and D (33.34%). By disk diffusion test 61.57% of isolates were resistant to cefotaxime, 35.64% to ceftazidime, 26.38% to aztreonam, 16.66% to cefepime and 6.48% to imipenem. Among the studied ESBL isolates, 72.41% isolates were positive for the CTX-M-15 gene. None of the isolates were positive for IMP, VIM, PER and VEB genes.Conclusion: The ESBL-producing strains were associated with shifts in phylogenetic distribution toward none-B2 phylo-groups and they mainly belonged to A and D groups.
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