Zoonotic potential of atypical enteropathogenic Escherichia coli (aEPEC) isolated from puppies with diarrhoea in Brazil.

Recent studies point atypical enteropathogenic Escherichia coli (aEPEC) to be an important agent in childhood diarrhoea in Brazil. aEPEC are commonly found in various animal species, including dogs. Although the true zoonotic risk remains unknown, some strains recovered from dogs present the same serotypes and carry the same virulence genes implicated in human disease. In this study, we compared the virulence and genetic relationship among a set of aEPEC strains previously isolated from diarrheic faeces from companion dogs and humans. A total of 17 strains, 12 from puppies and five from children, were studied. The strains were assessed for: (i) presence of virulence-associated genes (a total of 31 genes) using PCR assays; (ii) genetic relationship by Random Amplified Polymorphic DNA (RAPD), Multilocus Sequence Typing (MLST) and Pulsed-field Gel Electrophoresis (PFGE); and (iii) adherence pattern in intestinal Caco-2 cells. The occurrence of virulence genes was similar between the canine and human isolates presenting the same serotype. The fimbrial genes ecpA and fimH were the most frequently detected, followed by hcpA, tccP, tccP2, lpfA1, lpfA2, astA and toxB genes. Several nle genes were also detected, with one canine strain (O156:H- / ST327) showing all PAI O-122 genes investigated (efa-1, nleB, nleE and ent/espL2). Canine and human strains of the same serotype were grouped into a single cluster by RAPD and PFGE, in which the ST10 and ST206 were identified. Additionally, most of the strains exhibited a localized adherence-like phenotype when interacting with Caco-2 cells. The results showed that some canine aEPEC strains share virulence genes commonly found in human pathogenic strains. Moreover, strains of the same serotype, isolated from dogs and children, share virulence genes and are phylogenetically close, suggesting a potential zoonotic risk.

Antimicrobial resistance, integron carriage, and gyrA and gyrB mutations in Pseudomonas aeruginosa isolated from dogs with otitis externa and pyoderma in Brazil.

BACKGROUND: Pseudomonas aeruginosa is associated with otitis and pyoderma in dogs and is frequently resistant to several antimicrobial drugs. Resistance genes can be carried by integrons with quinolone resistance mainly due to mutations in DNA topoisomerases II and IV. OBJECTIVE: To evaluate the antimicrobial susceptibility, integron carriage, and gyrA and gyrB mutations in P. aeruginosa isolates from canine otitis and pyoderma. ANIMALS: One hundred and four P. aeruginosa strains isolated from dogs with otitis externa (n = 93) and pyoderma (n = 11). METHODS: Antimicrobial susceptibility against 16 antibacterial agents was evaluated through agar diffusion tests. Integron carriage, class and gyrA and gyrB mutations were analysed by PCR, restriction fragment length polymorphism (RFLP)-PCR and genetic sequencing assays. RESULTS: Isolates were mostly resistant to enrofloxacin (72.2%) and ticarcillin (59.7%). Lower resistance to ciprofloxacin (7.7%), tobramycin (3.8%) and polymixin B (0.0%) was detected. Ten (9.6%) multidrug-resistant (MDR) strains were detected. Eight (7.7%) strains carried class 1 integrons and this was associated with MDR (three isolates, P ≤ 0.05). Five of the integron-carrying strains exhibited aminoglycoside resistance genes. Mutations of gyrA and gyrB were observed in 10 isolates, seven of them resistant to all fluoroquinolones tested. CONCLUSIONS AND CLINICAL IMPORTANCE: Enrofloxacin and ticarcilin resistance was widespread in P. aeruginosa isolated from dogs in Brazil. Pseudomonas aeruginosa carrying integrons may present a significant challenge for treatment.