Virulence factors and genetic variability of uropathogenic Escherichia coli isolated from dogs and cats in Italy

In this study, the association between virulence genotypes and phylogenetic groups among Escherichia (E.) coli isolates obtained from pet dogs and cats with cystitis was detected, and fingerprinting methods were used to explore the relationship among strains. Forty uropathogenic E. coli (UPEC) isolated from dogs (n = 30) and cats (n = 10) in Italy were analysed by polymerase chain reaction (PCR) for the presence of virulence factors and their classification into phylogenetic groups. The same strains were characterized by repetitive extragenic palindromic (REP)- and enterobacterial repetitive intergenic consensus (ERIC)-PCR techniques. We found a high number of virulence factors such as fimbriae A, S fimbriae (sfa) and cytotoxic necrotizing factor 1 (cnf1) significantly associated with phylogenetic group B2. We demonstrated a high correlation between α-hemolysin A and pyelonephritis C, sfa, and cnf1 operons, confirming the presence of pathogenicity islands in these strains. In addition, UPEC belonging to group B2 harboured a greater number of virulence factors than strains from phylogenetic groups A, B1, and D. REP- and ERIC-PCR grouped the UPEC isolates into two major clusters, the former grouping E. coli strains belonging to phylogenetic group B2 and D, the latter grouping those belonging to groups A and B1. Given the significant genetic variability among the UPEC strains found in our study, it can be hypothesized that no specific genotype is responsible for cystitis in cats or dogs.     

Phylogenetic distribution of virulence genes in Escherichia coli isolated from bovine mastitis in Iran

One hundred and twenty seven Escherichia coli isolates from bovine mastitis were examined to detect the phylogenetic group/subgroups and a selection of virulence associated genes. Forty nine (38.58%) isolates belonged to group B1 the remaining isolates fell into four phylogenetic subgroups: A₀ (18.11%), A₁ (26.77%), D₁ (6.29%) and D₂ (10.23%). None of the isolates belonged to B2 group. Forty seven (37.00%) isolates were positive for at least one virulence gene, among them f17A was the most common gene, found in 20.47% of the isolates. Among the E. coli isolates, 11.81% had iucD, 9.44% f17c-A, 9.44% cnf2, 7.87% f17b-A, 6.29% afaD-8 and afaE-8, 3.14% f17d-A, 0.78% cnf1 and 0.78% clpG genes. All of the detected virulence genes were present alone or in combination with each other except clpG and f17d-A genes that were only found alone. None of the isolates contained the genes for F17a-A, intimin, P or S fimbriae.     

Phylogenetic background and virulence genes of Escherichia coli isolates from colisepticemic and healthy broiler chickens in Iran

The purposes of this study were to determine the phylogenetic background and the virulence gene profiles of Escherichia coli isolates from colisepticemic and feces of healthy (AFEC) broiler chickens. In this study, 253 E. coli isolates including 141 avian pathogenic E. coli (APEC) and 112 AFEC isolates were examined by PCR. In general, 253 E. coli isolates distributed among group A (51.8%), B1 (15.8%), B2 (8.7%), and D (23.7%). Ten (8.9%) AFEC isolates segregated in to B1 phylo-group and 102 (91.1%) isolates fell into six different phylogenetic subgroups. Distribution of colisepticemic and fecal isolates differed significantly in their assignments to A and B1 phylo-groups. The three most prevalent virulence genes were crl, fimH, and aer in isolates between both groups. The four genetic markers aer, papC, afa, and sfa were detected significantly more often among colisepticemic isolates than in fecal isolates from healthy broilers. The presence of stx ₂ gene in fecal isolates were significantly differs among the colisepticemic isolates. F17 fimbrial family encoding gene and eae gene were detected in APEC and AFEC isolates, respectively. The colisepticemic and fecal isolates possessed the virulence genes were detected in all of the four phylogenetic groups. Several combination patterns of the virulence genes were detected in APEC and AFEC isolates. In colisepticemic isolates the combination of aer, crl, and fimH genes was the most prevalent pattern. None of the examined isolates harbored the cdt, cnf1, ipaH, and stx ₁ virulence gene sequences.     

Determination of antibiotic resistance pattern and virulence genes in Escherichia coli isolated from bovine with subclinical mastitis in southwest of Iran

The aims of the present study were to investigate the prevalence of some virulence genes and also determine the antimicrobial resistance pattern of E. coli isolated from bovine with subclinical mastitis. The milk of 502 cows was collected from 8 dairy herds in the southwest of Iran. Conventional biochemical tests were used for identification of E. coli at the species level. Antimicrobial susceptibility patterns of E. coli isolates were determined by disc agar diffusion method and polymerase chain reaction (PCR) was used for detection of seven virulence genes including f17A, afaE-8, afaD-8, eaeA, cnf1, cnf2, and iucD. Seventy (13.94%) isolates of E. coli were identified in 502 milk samples. The highest rate of resistance was observed against tetracycline (18.6%), while none of the isolates were resistant to streptomycin. Eight (11.5%) out of 70 E. coli isolates carried at least one of the virulence genes. The afaD-8 was the most prevalent gene detected in 5 (7.1%) isolates. The afaE-8, iucD, and eaeA were detected in 3, 3, and 2 isolates respectively. Low prevalence of virulence factors may be indicating that most of the E. coli isolates originated from the commensal flora of cows and enter to the udders via environment contamination with feces.

     

Characteristics and virulence genes of <Emphasis Type="Italic">Escherichia coli</Emphasis> isolated from septicemic calves in southeast of Iran

Virulence factors are associated with the capacity of E. coli strains to cause intestinal and extraintestinal infections. Thirty one E. coli isolates were obtained from heart blood or internal organs of septicemic calves. The O serogroups of isolates were determined. PCR assays were performed to determine the phylogenetic groups and presence of specific virulence genes. Fourteen (45.16%) isolates belonged to seven O serogroups (O8, O15, O20, O45, O78, O101 and O103) and 17 (54.83%) isolates were O-nontypeable. E. coli isolates fall into three phylogenetic groups included 15 isolates belonged to B1, 9 to A and 7 to D phylogenetic groups. Nineteen (61.29%) isolates exhibited at least one of the virulence genes. F17 family (5 isolates f17b, 3 isolates f17c, 1 isolate f17a) genes and aerobactin encoding gene of iucD (5 isolates) were the two most prevalent virulence genes. Three isolates were positive for cnf2 and cdtIII genes in combination and they were O-nontypeable. AfaE-VIII, CS31A gene (clpG) and hemolysin encoding gene (hly) were detected in 3, 4 and 3 isolates respectively. None of the isolates contained the ipaH sequences and the genes encoding fimbria (F5, F41, S, P), AfaI adesin, toxins (LT-I, ST-I, SLT-I, SLT-II, CNF1 and CDT-IV) and intimin.     

Extraintestinal pathogenic Escherichia coli in poultry meat products on the Finnish retail market

Background

Extraintestinal pathogenic Escherichia coli bacteria (ExPEC) exist as commensals in the human intestines and can infect extraintestinal sites and cause septicemia. The transfer of ExPEC from poultry to humans and the role of poultry meat as a source of ExPEC in human disease have been discussed previously. The aim of the present study was to provide insight into the properties of ExPEC in poultry meat products on the Finnish retail market with special attention to their prevalence, virulence and phylogenetic profiles. Furthermore, the isolates were screened for possible ESBL producers and their resistance to nalidixic acid and ciprofloxacin was tested.

Methods

The presence of ExPEC in 219 marinated and non-marinated raw poultry meat products from retail shops has been analyzed. One E. coli strain per product was analyzed further for phylogenetic groups and possession of ten virulence genes associated with ExPEC bacteria (kpsMT K1, ibeA, astA, iss, irp2, papC, iucD, tsh, vat and cva/cv) using PCR methods. The E. coli strains were also screened phenotypically for the production of extended-spectrum β-lactamase (ESBL) and the susceptibility of 48 potential ExPEC isolates for nalidixic acid and ciprofloxacin was tested.

Results

E. coli was isolated from 207 (94.5%) of 219 poultry meat products. The most common phylogenetic groups were D (50.7%), A (37.7%), and B2 (7.7%). Based on virulence factor gene PCR, 23.2% of the strains were classified as ExPEC. Two ExPEC strains (1%) belonged to [O1] B2 svg+ (specific for virulent subgroup) group, which has been implicated in multiple forms of ExPEC disease. None of the ExPEC strains was resistant to ciprofloxacin or cephalosporins. One isolate (2.1%) showed resistance to nalidixic acid.

Conclusions

Potential ExPEC bacteria were found in 22% of marinated and non-marinated poultry meat products on the Finnish retail market and 0.9% were contaminated with E. coli [O1] B2 svg+ group. Marinades did not have an effect on the survival of ExPEC as strains from marinated and non-marinated meat products were equally often classified as ExPEC. Poultry meat products on the Finnish retail market may have zoonotic potential.     

Phylogenetic grouping,epidemiological typing,analysis of virulence genes,and antimicrobial susceptibility of Escherichia coli isolated from healthy broilers in Japan

Background

The aim of our study was to investigate the possible etiology of avian colibacillosis by examining Escherichia coli isolates from fecal samples of healthy broilers.

Findings

Seventy-eight E. coli isolates from fecal samples of healthy broilers in Japan were subjected to analysis of phylogenetic background, virulence-associated gene profiling, multi-locus sequence typing (MLST), and antimicrobial resistance profiling. Phylogenetic analysis demonstrated that 35 of the 78 isolates belonged to group A, 28 to group B1, one to group B2, and 14 to group D. Virulence-associated genes iutA, iss, cvaC, tsh, iroN, ompT, and hlyF were found in 23 isolates (29.5%), 16 isolates (20.5%), nine isolates (11.5%), five isolates (6.4%), 19 isolates (24.4%), 23 isolates (29.5%), and 22 isolates (28.2%) respectively. Although the genetic diversity of group D isolates was revealed by MLST, the group D isolates harbored iutA (10 isolates, 71.4%), iss (6 isolates, 42.9%), cvaC (5 isolates, 35.7%), tsh (3 isolates, 21.4%), hlyF (9 isolates, 64.3%), iroN (7 isolates, 50.0%), and ompT (9 isolates, 64.3%).

Conclusions

Our results indicated that E. coli isolates inhabiting the intestines of healthy broilers pose a potential risk of causing avian colibacillosis.     

Phenotypic and genotypic properties of Escherichia coli isolated from colisepticemic cases of Japanese quail

This study was conducted to characterize the Escherichia coli isolates from colisepticemic Japanese quails. One hundred and nine E. coli were isolated in pure culture from heart blood of dead Japanese quails. The sampled birds were originated from four different farms. Antibiotic resistance pattern of E. coli isolates were determined against nine antibacterial agents. Phylotype and virulence genes of the isolates were detected by polymerase chain reaction. By disc diffusion method, all of the isolates showed resistance to three or more antibiotics, and 19 different patterns of multiple drug resistance were observed. Phylotyping of the most prevalent multiple drug-resistant isolates revealed that they mostly belonged to phylogroups A (A₁ subgroup). The E. coli isolates belong to four phylogenetic groups: A (55.0%), B1 (18.3%), B2 (17.4%), and D (9.2%). Eighty-nine (81.7%) isolates were distributed in five phylogenetic subgroups including 22 (20.2%) in A₀, 38 (34.9%) in A₁, 19 (17.4%) in B2₃, 7 (6.4%) in D₁, and 3 (2.8%) in D₂. The examined E. coli isolates exhibit at least one of the virulence genes tested, whereas three most prevalent genes were crl (94.5%), fimH (89.0%), and iutA (51.4%), respectively. The genetic marker for Afa (afaI B-C), S (sfa/focD-E), and P (papE-F) fimbriae were found in one, four, and ten isolates, respectively. Thirteen different combinations of virulence gene were observed, where combination of crl and fimH genes was the most prevalent pattern. None of the isolates contained the ipaH, stx1, stx2, and eaeA genetic markers. In conclusion, E. coli strains could be considered as a causative agent of mortality in quail farms. In conclusion, E. coli isolates from colisepticemic quails are distributed in different phylogroups, are resistant to combinations of antibiotic agents, and contain several virulence genes.     

Antimicrobial resistance in Escherichia coli isolates from frugivorous (Eidolon helvum) and insectivorous (Nycteris hispida) bats in Southeast Nigeria,with detection of CTX-M-15 producing isolates

Thirty-five Escherichia coli isolates obtained from the liver, spleen and intestines of 180 frugivorous and insectivorous bats were investigated for antimicrobial resistance phenotypes/genotypes, prevalence of Extended-Spectrum beta-lactamase (ESBL) production, virulence gene detection and molecular typing. Eight (22.9 %) of the isolates were multidrug resistant (MDR). Two isolates were cefotaxime-resistant, ESBL-producers and harbored the bla_CTX-M-15 gene; they belonged to ST10184-D and ST2178-B1 lineages. tet(A) gene was detected in all tetracycline-resistant isolates while int1 (n = 8) and bla_TEM (n = 7) genes were also found. Thirty-three of the E. coli isolates were assigned to seven phylogenetic groups, with B1 (45.7 %) being predominant. Three isolates were enteropathogenic E. coli (EPEC) pathovars, containing the eae gene (with the variants gamma and iota), and lacking stx1/stx2 genes. Bats in Nigeria are possible reservoirs of potentially pathogenic MDR E. coli isolates which may be important in the ecology of antimicrobial resistance at the human-livestock-wildlife-environment interfaces. The study reinforces the importance of including wildlife in national antimicrobial resistance monitoring programmes.     

Population structure and virulence content of avian pathogenic Escherichia coli isolated from outbreaks in Sri Lanka

Avian pathogenic Escherichia coli (APEC) causes economically significant infections in poultry. The genetic diversity of APEC and phylogenetic relationships within and between APEC and other pathogenic E. coli are not yet well understood. We used multilocus sequence typing (MLST), PCR-based phylogrouping and virulence genotyping to analyse 75 avian E. coli strains, including 55 isolated from outbreaks of colisepticaemia and 20 from healthy chickens. Isolates were collected from 42 commercial layer and broiler chicken farms in Sri Lanka. MLST identified 61 sequence types (ST) with 44 being novel. The most frequent ST, ST48, was represented by only six isolates followed by ST117 with four isolates. Phylogenetic clusters based on MLST sequences were mostly comparable to phylogrouping by PCR and MLST further differentiated phylogroups B1 and D into two subgroups. Genotyping of 16 APEC associated virulence genes found that 27 of the clinical isolates and one isolate from a healthy chicken belonged to highly virulent genotype according to previously established classification schemes. We found that a combination of four genes, ompT, hlyF, iroN and papC, gave a comparable prediction to that of using five and nine genes by other studies. Four STs (ST10, ST48, ST117 and ST2016) contained APEC isolates from this study and human UPEC isolates reported by others, suggesting that these STs are potentially zoonotic. Our results enhanced the understanding of APEC population structure and virulence association.     

Serogrouping,phylotyping, and virulence genotyping of commensal and avian pathogenic Escherichia coli isolated from broilers in Hamedan,Iran

In the present study, 100 Avian-Pathogenic Escherichia coli (APEC) isolates from colibacillosis-suspected broilers and 100 Avian Faecal Escherichia coli (AFEC) isolates from healthy broilers in Iran were examined by PCR for confirmation of their serogroups and phylogenetic background, and their association with ten virulence-associated genes (VAG) including fimC, iutA, chuA, sitA, iss, cvaA/B, hylA, stx1, stx2, and yjaA. Serogroups O78, O1, O2 and O18 were the prominent strains including 54 % of the APEC and 23 % of the AFEC strains. At phylotyping, the majority of APEC strains belonged to phylogenetic group E (22 %) while for the AFEC strains, half of the isolates were not assigned to any group but the predominant phylogroup was E (27 %). Virulence genotyping, revealed that the predominant VAGs were iutA (97 %), fimC (87 %) and iss (84 %) among APEC strains, and fimC (95 %), iss (93 %) and sitA (87 %) in AFEC strains. This is the first time that phylogroup E is described as predominant phylogroup among APEC strains also, this is the first report on the presence of the stx1 gene in APEC strains isolated from broilers in Iran. The results of the present study indicate that VAGs are more prevalent in APEC strains belonging to O2 and O78 serogroups, also phylogroups E and D have more frequency of VAGs than other phylogroups. Therefore, the APEC strains belonging to O2 and O78 serogroups and phylogroups E and D probably have more pathogenicity to broilers.     

Antimicrobial resistance and virulence factors in Escherichia coli from swedish dairy calves

Background

In Sweden, knowledge about the role of enteropathogenic Escherichia coli in neonatal calf diarrhea and the occurrence of antimicrobial resistance in E. coli from young calves is largely unknown. This has therapeutic concern and such knowledge is also required for prudent use of antimicrobials.

Methods

In a case control study Esherichia coli isolated from faecal samples from dairy calves were phenotyped by biochemical fingerprinting and analyzed for virulence genes by PCR. Antimicrobial susceptibility was tested by determination of minimum inhibitory concentration (MIC). Farm management data were collected and Fisher''s exact test and univariable and multivariable logistic regression analysis were performed.

Results

Of 95 E. coli tested for antimicrobial susceptibility 61% were resistant to one or more substances and 28% were multi-resistant. The virulence gene F5 (K99) was not found in any isolate. In total, 21 out of 40 of the investigated virulence genes were not detected or rarely detected. The virulence genes espP, irp, and fyuA were more common in resistant E. coli than in fully susceptible isolates (P < 0.05). The virulence gene terZ was associated with calf diarrhea (P ≤ 0.01).The participating 85 herds had a median herd size of 80 lactating cows. Herds with calf diarrhea problems were larger (> 55 cows; P < 0.001), had higher calf mortality (P ≤ 0.01) and calf group feeders were more in use (P < 0.05), compared to herds without calf diarrhea problems.There was no association between calf diarrhea and diversity of enteric E. coli.

Conclusions

Antimicrobial resistance was common in E. coli from pre-weaned dairy calves, occurring particularly in calves from herds experiencing calf diarrhea problems. The results indicate that more factors than use of antimicrobials influence the epidemiology of resistant E. coli.Enteropathogenic E. coli seems to be an uncommon cause of neonatal calf diarrhea in Swedish dairy herds. In practice, calf diarrhea should be regarded holistically in a context of infectious agents, calf immunity, management practices etc. We therefore advice against routine antimicrobial treatment and recommend that bacteriological cultures, followed by testing for antimicrobial susceptibility and for virulence factors, are used to guide decisions on such treatment.     

Streptococcal infection as a cause of reproductive tract problems of swine

This study determined that streptococci were the etiological agents responsible for a high percentage of breeding sows experiencing infertility and abortions.No isolations of virus were obtained from fetuses, or placentae. There was no positive serology obtained from sows that aborted when tested for evidence of virus, leptospira, brucella, and eperythrozoon antibodies. Streptococci were the predominant isolates obtained from the genito-urinary tract of sows and boars. Cultures were taken from 75 sows and 46 (61%) yielded hemolytic streptococci; 27 of these streptococci belonged to a specific serogroup. Of the 75 sows studied, 46 were infected, and of these, nine aborted, 14 were infertile, and 23 farrowed normally. There was a significantly (P < 0.02) higher number of sows that had abortions or were infertile in the infected group. A random sample of 18 sows given penicilin therapy indicated a significant benefit from treatment (P < 0.02) in the reproductive performance of infected animals.Twelve out of 16 boars yielded hemolytic streptococci with seven isolated being of a specific serogroup.The percentage distribution of all streptococci isolates belonging to a specific serogroup was 63.4% group C, 22% group D, and 7.3% each fooup A and G.     

Characterisation of Escherichia fergusonii isolates from farm animals using an Escherichia coli virulence gene array and tissue culture adherence assays

Escherichia fergusonii has been associated with a wide variety of intestinal and extra-intestinal infections in both humans and animals but, despite strong circumstantial evidence, the degree to which the organism is responsible for the pathologies identified remains uncertain. Thirty isolates of E. fergusonii collected between 2003 and 2004 were screened using an Escherichia coli virulence gene array to test for the presence of homologous virulence genes in E. fergusonii. The iss (increased serum survival) gene was present in 13/30 (43%) of the test strains and the prfB (P-related fimbriae regulatory) and ireA (siderophore receptor IreA) genes were also detected jointly in 3/30 (10%) strains. No known virulence genes were detected in 14/30 (47%) of strains. Following confirmatory PCR and sequence analysis, the E. fergusoniiprfB, iss and ireA genes shared a high degree of sequence similarity to their counterparts in E. coli, and a particular resemblance was noted with the E. coli strain APEC O1 pathogenicity island. In tissue culture adherence assays, nine E. fergusonii isolates associated with HEp-2 cells with a ‘localised adherence’ or ‘diffuse adherence’ phenotype, and they proved to be moderately invasive. The E. fergusonii isolates in this study possess both some phenotypic and genotypic features linked to known pathotypes of E. coli, and support existing evidence that strains of E. fergusonii may act as an opportunistic pathogens, although their specific virulence factors may need to be explored.     

Characterization of non-O157 shiga toxin-producing Escherichia coli isolates from healthy fat-tailed sheep in southeastern of Iran

The objectives of this study were to determine the presence and prevalence of non-O157 shiga toxin-producing Escherichia coli (STEC) isolates from faeces of healthy fat-tailed sheep and detection of phylogenetic background and antibiotic resistance profile of isolates. One hundred ninety-two E. coli isolates were recovered from obtained rectal swabs and were confirmed by biochemical tests. Antibiotic resistance profiles of isolates were detected and phylogenetic background of isolates was determined according to the presence of the chuA, yjaA and TspE4.C2 genetic markers. The isolates were examined to determine stx ₁ , stx ₂ and eae genes. Non-O157 STEC isolates were identified by using O157 specific antiserum. Forty-three isolates (22.40 %) were positive for one of the stx ₁ , stx ₂ and eae genes, whereas 10.42 % were positive for stx ₁ , 19.38 % for eae and 2.60 % for stx ₂ gene. None of the positive isolates belonged to O157 serogroup. Twenty isolates possessed stx ₁ were distributed in A (six isolates), B1 (13) and D (one) phylogroups, whereas stx ₂ positive isolates fell into A (three isolates) and B1 (two) phylogenetic groups. Eighteen isolates contained eae gene belonged to A (five isolates), B1 (seven) and D (six) phylogroups. The maximum and minimum resistance rates were recorded against to penicillin and co-trimoxazole respectively. The positive isolates for stx ₁ , stx ₂ and eae genes showed several antibiotic resistance patterns, whereas belonged to A, B1 and D phylogroups. In conclusion, faeces of healthy sheep could be considered as the important sources of non-O157 STEC and also multidrug-resistant E. coli isolates.     

Occurrence of genes encoding aminoglycoside-modifying enzymes in Escherichia coli isolates from chicken meat

ABSTRACT

1. The aim of the experiment was to determine the occurrence of genes encoding aminoglycoside-modifying enzymes (AMEs) in Escherichia coli isolates recovered from chicken meat.

2. Antibiotic sensitivity was tested using the disc diffusion test. AMEs and virulence profile were determined by PCR/sequencing.

3. Out of 195 meat samples collected, 185 (95%) isolates were identified as E. coli. Disc diffusion showed a resistance value of 22% (n = 42) for at least one of the antibiotic aminoglycosides (AGs) tested (tobramycin, gentamycin, amikacin and kanamycin). PCR screening showed the presence of three classes of AMEs, namely, aac(3)-II (12%), aac(6?)-Ib (7%) and aac(2?)-Ia (5%). Eight of the 42 isolates were positive for the stx₁ and sxt₂ genes and were defined as Shiga toxin-producing E coli., while the eae gene was positive in one strain. Among the 42 isolates, group A was the predominant phylogenetic identified (76%), followed by group D (21%). One isolate belonged to subgroup B2₃.

4. The results suggested that chicken meat could be an important reservoir of AMEs, and pose a potential risk by dissemination of resistance to humans through the food chain.     

Isolation of Escherichia coli from piglets in South Korea with diarrhea and characteristics of the virulence genes

Escherichia coli was isolated from the feces of 122 piglets with diarrhea on 55 farms in Korea. The virulence genes of each isolate were characterized by polymerase chain reaction (PCR). Of the 562 isolates, 191 carried 1 or more of the virulence genes tested for in this study. Of the 191 isolates, 114 (60%) carried 1 or more of the genes for enterotoxigenic E. coli (ETEC) fimbriae F4, F5, F6, F18, and F41 and ETEC toxins LT, STa, and STb, 57 (30%) carried 1 or more of the genes for the Shiga-toxin-producing E. coli (STEC) toxins Stx1, Stx2, and Stx2e, and 21% and 37% carried the gene for enteropathogenic E. coli intimin and for enteroaggregative E. coli toxin, respectively. Collectively, our results indicate that other pathotypes of E. coli as well as ETEC can be strongly associated with diarrhea in piglets. In addition, detection of the genes for Stx1 and Stx2 indicates that pigs are reservoirs of human pathogenic STEC.     

Antibiogram,virulotyping and genetic diversity of Escherichia coli and Salmonella serovars isolated from diarrheic calves and calf handlers

Antimicrobial resistance profile of E. coli and Salmonella serovars isolated from diarrheic calves and handlers in Egypt is unknown due to the absence of monitoring. Therefore, this study aimed to determine the virulence, genetic and antimicrobial resistance profiles of E. coli and Salmonella serovars associated with diarrhea in calves and handlers in intensive dairy farms in Egypt. A total of 36 bacterial strains (20 E. coli and 16 Salmonella) were isolated from fecal samples of 80 diarrheic Holstein dairy calves (10 E. coli and 13 Salmonella) and hand swabs of 35 handlers (10 E. coli and 3 Salmonella) in two intensive dairy farms in Sharkia Governate in Egypt. E. coli strains belonged to six different serogroups and O114:K90 was the most prevalent serogroup (30%). However, Salmonella strains were serotyped into four different serogroups and S. Kiel was the most prevalent serotype (50%). Thirteen (65%) E. coli isolates were harbouring either stx2, eaeA and/or astA virulence-associated genes. However, stn and spvC virulence genes were detected in 2 (12.5%) and 4 (25%) of Salmonella isolates, respectively. E. coli isolates showed marked resistance to ampicillin (75%), while Salmonella strains exhibited high resistance to amikacin (100%), gentamicin (93.75%) and tobramycin (87.5%). Results of the present study showed that E. coli and Salmonella serovars isolated from diarrheic calves and handlers in intensive dairy farms in Egypt exhibited resistance to multiple classes of antimicrobials, which may pose a public health hazard. Thus, the continuous monitoring of antimicrobial resistance is necessary for both humans and veterinary medicine to decrease the economic losses caused by antimicrobial-resistant strains in animals as well as the zoonotic risk.     

Serogroup distribution,diversity of exotoxin gene profiles,and phylogenetic grouping of CTX-M-1- producing uropathogenic Escherichia coli

The emergence of CTX-M-1 producing Uropathogenic Escherichia coli (UPEC) has become a serious challenge. In addition to antimicrobial resistance, a number of virulence factors have been shown. Therefore, this study was designed to determine the prevalence of O- serogroups, phylogenetic groups, exotoxin genes, and antimicrobial resistance properties of CTX-M-1- producing UPEC. A total of 248 UPEC isolates were collected. The antibiotic resistance was performed, and PCR was used to detect the bla_CTX-M1, exotoxins, serogroups and phylogroups of UPEC. Of 248 isolates, 95 (38.3%) harbored bla_CTX-M-1. Of them, serogroups O1 and O25 were predominant, accounting for 20% and 13.7%, respectively. The hlyA was the dominant exotoxin gene (32.6%), followed by sat (28.4%), vat (22.1%), cnf (13.7%), picU (8.4%), and cdt (2.1%). The hlyA gene was significantly associated with pyelonephritis (P = 0.003). Moreover, almost half of the isolates (45.4%) belonged to phylogenetic group B2. Most of exotoxin genes were present in significantly higher proportions in group B2 isolates except cdt gene (P < 0.05). All of the isolates were susceptible to imipenem, nitrofurantoin, and fosfomycin. The CTX-M-1-producing UPEC strains causing nosocomial infections are more likely to harbor certain exotoxin genes, raising the possibility that this increase in virulence genes may result in an increased risk of complicated UTI.