Identification of intimin alleles in pathogenic Escherichia coli by PCR-restriction fragment length polymorphism analysis

A rapid two-step identification method based on PCR-RFLP analysis of the intimin gene was developed to differentiate specific alleles in pathogenic Escherichia coli. This technique, tested on isolates eae-positive, accurately detects eae and resolves alleles encoding the α1, α2, β, γ1, γ2/θ, κ, ɛ, ζ, and ι intimin variants

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

Retrospective analysis of antibacterial resistance among uropathogen Escherichia coli in a veterinary teaching hospital (Italy, 2014-2019)

Background: Urinary tract infections (UTIs) often require long follow-up periods and repeated antimicrobial therapies that can lead to the onset of antimicrobial-resistance. Escherichia coli is the most frequent bacterium involved in uncomplicated UTIs in pet animals in which treatment is sometimes threatened by the steady increase in the number of strains bearing concurrent resistance to various antimicrobial agents. The study aimed to report the variation of antibacterial resistance of urinary pathogen E. coli (UPEC) isolated from pets in a veterinary teaching hospital, North Italy (Turin) during a 5-and-a-half-year period (2014-2019). Materials/methods: This retrospective study was carried out on E. coli strains (n= 219) collected from dogs (n=139) and cats (n=80) with UTI. Each strain was tested to 18 antibiotics belonging to 8 categories: aminoglycosides, carbapenems, folate pathway inhibitors, not-extended spectrum cephalosporins: 1st and 2nd generation, extended spectrum cephalosporins: 3rd and 4th generation, penicillins, penicillins + β-lactamase inhibitors, quinolones, following Kirby-Bauer method and interpreted according to the EUCAST guidelines. Isolates were classified as MDR (multidrug-resistant), XDR (MDR susceptible to only one or two antibiotic categories) and PDR (resistant to all agents tested). Data were analyzed using χ2 test, Pearson’s correlation among years and variance-weighted least-square regression models with STATA 15.1, choosing a significance level of α=0.05. Results: Out of 219 UPEC, 114 (52.05%) of them were MDR, of which 37 were XDR and 1 was PDR. Increasing resistance among years was seen for 4 out o 8 classes of antimicrobial agents. An overall increase in MDR proportion (coeff. = 0.074; 95CI 0.038- 0.110), and in the number of concurrent resistances (coeff. = 0.297; 95CI 0.126-0.467) were assessed. A significative difference in the baseline level of resistances and the rising of them was observed between dogs and cats. Conclusions: Approximately half of isolated strains were MDR (52.05%), but they came all from clinically ill patients, which might suggest that the prevalence in the general pet population is lower. Nevertheless the upward trend of antimicrobial resistance of UPEC to various antibiotics, the rise in the amount of concurrent resistances and the presence of XDRs and a PDR strain, poses serious public health issues