Evaluation of antibacterial resistance in Vibrio strains isolated from imported seafood and Italian aquaculture settings

Abstract

Ninety-two Vibrio strains isolated over a period of 9 years from different sources (national and imported fishery products, shellfish, seawater from aquaculture settings, etc.) and belonging mostly to two species relevant for human health and fish pathology, V. parahaemolyticus and V. alginolyticus, were tested for resistance to different antibacterials using the standard disk diffusion test (five antibacterials: ampicillin, sulfamethoxazole, tetracycline, trimethoprim/sulfamethoxazole and chloramphenicol) and the Minimum Inhibitory Concentrations method (six antibacterial families: β-lactams, tetracyclines, chloramphenicol, aminoglycosides, quinolones, trimethoprim/sulfamethoxazole) providing consistent results. The analysis performed by standard disk diffusion test showed resistance to ampicillin in 82% of the strains, whereas 7% were resistant to sulfamethoxazole, 3% to tetracycline, and 1% to trimethoprim/sulfamethoxazole; no strain was found to be resistant to chloramphenicol. The results obtained by the MIC tests, because of the absence of established breakpoints for some antibacterials, were not readily interpretable for all substances, but showed no statistically significant difference to the results obtained by the standard disk diffusion test. Beside these results, high MIC 90 values (128 μg ml −1 and above) were obtained for kanamycin and streptomycin, indicating that high concentrations of these antibacterials were required to inhibit the growth of the strains. Strains exhibiting resistance or intermediate resistance to two or more antibacterials represented 15% of the total and included, beside resistance to ampicillin, resistance to sulfamethoxazole or, for V. parahaemolyticus isolates, tetracycline. Interestingly, differences in the mechanism of resistance to β-lactams were detected between the species V. parahaemolyticus and V. alginolyticus.

Prevalence and Antimicrobial Resistance of Vibrio parahaemolyticus Isolated from Raw Shellfish in Poland

“…Antimicrobial resistance among the V. parahaemolyticus tested revealed that most isolates (87.5%) were resistant to ampicillin (56 of 64 isolates; Table 3). These data are similar to the results from other countries where V. parahaemolyticus of shellfish origin were mainly resistant to p-lactams (ampicillin) (9,10,13,19,31). In other investigations, especially from Asia, 100% of isolates were resistant to this antimicrobial (14,30).…”

Reconnaissance of 47 antibiotics and associated microbial risks in seafood sold in the United States

“…Furthermore, the transfer of plasmids among bacteria on seafood has been reported [37]. Strains were found to have minimal inhibitory concentrations (MIC) far lower than the MIC requirement for the “resistant” classification, indicating that very low concentrations of antibiotics can select for resistance.…”

Antibiotic-Resistance Profiles and the Identification of the Ampicillin-Resistance Gene of Vibrio parahaemolyticus Isolated from Seawater

“…Trimethoprim에 내성을 갖는 장염비브리오는 classs I integron 내에 존재하는 dfrA27 유전자 에 의해 trimethoprim, gentamicin 및 rifampin의 내성에 관여하 는 유전자가 포함되어 있다는 연구결과가 최근에 보고하였다 (Yu et al, 2010 (Lee et al, 2007;Lee et al, 2009). 이러한 결과는 우리나라에만 국한되고 있는 것이 아니라 외국의 예도 유사한 실정이다 (Tanil et al, 2005;Baker-Austin et al, 2008;Ferrini et al, 2008 (Fig. 1A와 B).…”