Insight Into Whole Genome of Aeromonas veronii Isolated From Freshwater Fish by Resistome Analysis Reveal Extensively Antibiotic Resistant Traits

Abstract

Aeromonas veronii outbreaks in tilapia farming caused relatively high mortalities, and the bacteria was resistant to many kinds of antimicrobials used in Thailand aquaculture. According to the CLSI standard, the determination of antimicrobials efficacy has been limited to phenotypic analyses, and a genomics study is required. This research aimed to analyze the resistome of A. veronii isolated from diseased tilapia in Chainat, Nong Khai, and Uttaradit provinces in Thailand. A total of 12 isolates of A. veronii were identified based on the gyrB sequencing and then, the MIC values to eight antimicrobials (AMP, AML, GEN, ENR, OXO, OTC, SXT, and FFC) were determined. According to the MIC patterns, whole genome sequencing (WGS) of five representatives and resistome analysis were performed, including 15 genomes of A. veronii isolated from freshwater fish available in the NCBI. All tilapia isolates were susceptible to FFC but resistant to AML and AMP while OTC resistance was the most dominant. In addition to the WGS analysis, 4.5 Mbp of A. veronii was characterized. A total of 20 ARGs were detected by resistome analysis and 16 genes were shared among the A. veronii population. In conclusion, A. veronii strains isolated from tilapia exhibited a resistance to several antimicrobials and multidrug resistance (MDR) which was related to the presence of multiple ARGs. Aeromonas veronii shared the ARGs in their population worldwide with a possibility of a plasmid-mediated acquisition due to the presence of resistance islands.

Aeromonas hydrophila ST251 and Aeromonas dhakensis are major emerging pathogens of striped catfish in Vietnam

“…isolates, and a minor group related to A. jandaei and A. sobria (Figure 1). This is consistent with other studies that have implicated species other than A. hydrophila in MAS outbreaks, including A. veronii in channel catfish in Vietnam (Hoai et al, 2019) and carp in China (Ran et al, 2018), and A. veronii and A. jandaei in tilapia in Thailand (Dong et al, 2017;Sakulworakan et al, 2021). This present study relied on opportunistic sampling and a structured epidemiological approach is necessary to understand the relative contributions of A. hydrophila including vAh ST251, A. dhakensis and other Aeromonas species and strains to MAS outbreaks in striped catfish in Vietnam.…”

Diversity and antimicrobial susceptibility profiles of Aeromonas spp. isolated from diseased freshwater fishes in Thailand

“…Our findings revealed that more than 90% of Aeromonas strains showed resistance to β‐lactam antibiotics such as AMC and AMP. These results also agree with the previous studies reported by many researchers (Azzam‐Sayuti et al, 2021; Sakulworakan et al, 2021). Many Aeromonas strains isolated from diseased freshwater fish in the studied ponds exhibited high antibiotic resistance against AMC and AMP, indicating that chromosomal encode β‐lactam resistance genes frequently produced in Aeromonas isolates microbes in the studied aquatic environment (Saavedra et al, 2004; Soto‐Rodriguez et al, 2018).…”

“…The aquaculture policy in Thailand allows several types of antibiotic groups, including beta‐lactams, quinolones, tetracyclines, and sulfonamides (FCSTD, 2012). These antibiotics have also been used frequently for human treatments (Sakulworakan et al, 2021). Nonprudent use of antimicrobials in aquaculture will significantly impact the development of antimicrobial‐resistant bacteria, transfer resistance properties between bacteria, and reduce the effectiveness of drugs for aquatic and terrestrial animals as well as humans (Rhodes et al, 2000; Yano et al, 2015).…”

Aeromonas species isolated from aquatic organisms, insects, chicken, and humans in India show similar antimicrobial resistance profiles

“…Although the pangenome classified the 15 genomes into four groups based on species, the high similarity of AMR genes determined by phylogenetic analyses is suggestive that there is interspecies transmission of AMR genes among bacteria species isolated from different hosts. This is also indicative that these genes could be part of the conserved genome across the aeromonads being in line with previous observations that Aeromonads are intrinsically resistant to β-lactams (Baron et al, 2017;Kabwe et al, 2020;Sakulworakan et al, 2021).…”