Prevalence, antimicrobial resistance, and staphylococcal toxin genes of blaTEM-1a -producing Staphylococcus aureus isolated from animals in Chongqing, China

Dynamics of antimicrobial resistance and virulence of staphylococcal species isolated from foods traded in the Cape Coast metropolitan and Elmina municipality of Ghana

The impact of staphylococci on food poisoning and infections could be higher than previously reported. In this study, we characterised the occurrence and coexistence of antimicrobial resistance and virulence genes of staphylococci isolates in foods. Staphylococci were isolated from 236 samples of selected street-vended foods and identified. The pattern of antimicrobial resistance and virulence genes in the staphylococci were assessed using disc diffusion, PCR and analysis of next-generation sequencing data. The food samples (70.76 %) showed a high prevalence of staphylococci and differed among the food categories. Forty-five Staphylococcus species were identified and comprised coagulase-negative and positive species. Staphylococcus sciuri (now Mammaliicoccus sciuri), S. aureus, S. kloosii, S. xylosus, S. saprophyticus, S. haemolyticus and S. succinus were the most abundant species. The staphylococcal isolates exhibited resistance to tetracycline, levofloxacin, ciprofloxacin, norfloxacin, gentamicin and amikacin and susceptibility to nitrofurantoin. Antimicrobial susceptibilities were also reported for cefoperazone, ceftriaxone, cefotaxime, nalidixic acid and piperacillin-tazobactam. The antimicrobial resistance and virulence genes commonly detected consisted of tet, arl, macB, van, gyr, nor, optrA, bcrA, blaZ, taeA and S. aureus lmrS. The isolates frequently exhibited multiple resistance (30.42 %) of up to eight antimicrobial drug classes. The isolates predominantly harboured genes that express efflux pump proteins (50.53 %) for antibiotic resistance compared with inactivation (10.05 %), target alteration (26.72 %), protection (7.67 %) and replacement (3.17 %). The virulence determinants comprised genes of pyrogenic toxin superantigens (eta, etb, tst), adhesions (clf, fnbA, fnbB, cna, map, ebp, spA, vWbp, coa) and genes that express exoproteins (nuclease, metalloprotease, γ-hemolysin, hyaluronate lyase). There was a statistically significant difference in the prevalence of staphylococci isolates and their antimicrobial resistance and virulence profile as revealed by the phenotypic, PCR and next-generation sequencing techniques. The findings suggest a higher health risk for consumers. We recommend a critical need for awareness and antimicrobial susceptibility and anti-virulence strategies to ensure food safety and counteract the spread of this clinically relevant genus.

In Vitro Antimicrobial Activity of Thymus vulgaris, Origanum vulgare, Satureja montana and Their Mixture against Clinical Isolates Responsible for Canine Otitis Externa

Otitis externa is a frequent inflammation among dogs, mainly caused by bacteria and yeasts that are often resistant to conventional drugs. The aim of the present study was to evaluate the in vitro antibacterial and antifungal activities of commercial essential oils (EOs) from Origanum vulgare, Satureja montana, and Thymus vulgaris, as well as a mixture of these three components, against 47 clinical bacterial strains (Staphylococcus sp., Streptococcus sp., Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Serratia marcescens) and 5 Malassezia pachydermatis strains, previously cultured from the ears of dogs affected by otitis externa. The tested Gram-positive bacteria were sensible to the analysed EOs with MICs ranging from 1.25% (v/v) to <0.0195% (v/v); Gram-negative isolates, mainly P. aeruginosa, were less sensitive with MICs from >10% (v/v) to 0.039% (v/v). M. pachydermatis isolates were sensitive to all EOs with MICs from 4.25% (v/v) to 2% (v/v). However, the mixture was active against all bacterial (except one P. aeruginosa strain) and fungal tested isolates. The three EOs and their mixture seem to be an interesting alternative for treating canine otitis externa when conventional antimicrobials are not active.