Occurrence of multiple antibiotic resistance and genotypic characterization inEdwardsiella tardaisolated from cage‐cultured hybrid red tilapia (Oreochromissp.) in the Ping River, Northern Thailand

Abstract

Edwardsiella tarda is a pathogen that causes edwardsiellosis in aquatic animals. The emergence of multiple antibiotic‐resistant strains makes antibiotic treatment difficult. This study aimed to investigate the antibiotic susceptibility patterns and the genotypic characterization of E. tarda isolated from cage‐cultured red tilapia in Thailand. A total of 30 isolates were identified as E. tarda using biochemical and molecular analysis. The disc diffusion method for testing antibiotic susceptibility showed all the isolates were resistant to colistin sulphate and oxolinic acid. High levels of resistance to amoxicillin, ampicillin, ceftazidime, oxytetracycline and sulphamethoxazole/trimethoprim were observed as well. The multiple antibiotic resistance index ranged from 0.25 to 0.92, indicating that these isolates had been exposed to high risk sources of contamination where antibiotics were commonly used. All the isolates carried the blaTEM gene based on polymerase chain reaction (PCR). The tetA and sul3 genes were detected in 90% (27/30) and 26.7% (8/30) of the isolates respectively. Nine different genetic groups of isolates were obtained using enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC‐PCR). A correlation between genetic types and multiple antibiotic‐resistant patterns was found. These results highlight the potential risks of multiple antibiotic‐resistant isolates for humans and the environment.

A peek into mass mortality caused by antimicrobial resistant Edwardsiella tarda in goldfish, Carassius auratus in Kerala

“…It was reported that E.tarda is naturally resistant to macrolides and glycopeptides (Stock and Wiedemann 2001) which is in close agreement with the present finding. Niu et al (2019) also documented the multidrug resistance of E. tarda associated with Tilapia towards tetracyclines, sulphonamides and beta-lactams; which supported the present finding. The establishment of multiple antimicrobial resistance in the fish pathogens affects the successful antibiotic treatment.…”

Phenotypic and genotypic characterization of Streptococcus spp. isolated from tilapia (Oreochromis spp.) cultured in river‐based cage and earthen ponds in Northern Thailand

“…GBS and S. iniae were found to be susceptible to most of the antimicrobials tested in the present study, showing that OTC, ENR and AML were effective for the control of those pathogens. However, the occurrence of MDR bacteria in aquaculture in Thailand has been reported (Niu, Wongsathein, Boonyayatra, & Khattiya, ; Tipmongkolsilp et al, ). The upshot is that monitoring of the usage of antimicrobials is crucial to reducing potential risks to environmental and human health.…”

Environmentally relevant concentrations of triclosan exposure promote the horizontal transfer of antibiotic resistance genes mediated by Edwardsiella piscicida

“…However, there is no effective commercial vaccine available, and antimicrobial-medicated feeds are still a commonly used strategy to control edwardsiellosis (Leung et al 2019 ). The occurrence of multiple antibiotic-resistant E. piscicida is presently very common (Lo et al 2014 ; Niu et al 2019 ). For example, its resistance to oxytetracycline and ampicillin ranges from 21 to 90% and 73.3 to 100.0%, respectively (Lo et al 2014 ; Niu et al 2019 ).…”

“…The occurrence of multiple antibiotic-resistant E. piscicida is presently very common (Lo et al 2014 ; Niu et al 2019 ). For example, its resistance to oxytetracycline and ampicillin ranges from 21 to 90% and 73.3 to 100.0%, respectively (Lo et al 2014 ; Niu et al 2019 ). Approximately 70% of isolates from red tilapia in northern Thailand were resistant to at least seven antibiotics (Niu et al 2019 ).…”