Prevalence, antibiotic susceptibility, and presence of drug resistance genes in Aeromonas spp. isolated from freshwater fish in Kelantan and Terengganu states, Malaysia

Abstract

Background and Aim: The emergence of antibiotic-resistant bacterial pathogens has been increasingly reported, which has resulted in a decreasing ability to treat bacterial infections. Therefore, this study investigated the presence of Aeromonas spp., including its antibiotic resistance in various fish samples, Oreochromis spp., Clarias gariepinus, and Pangasius hypophthalmus, obtained from Kelantan and Terengganu, Malaysia. Materials and Methods: In this study, 221 fish samples, of which 108 (Oreochromis spp., n=38; C. gariepinus, n=35; and P. hypophthalmus, n=35) were from Kelantan and 113 (Oreochromis spp., n=38; C. gariepinus, n=35; and P. hypophthalmus, n=40) were from Terengganu, were caught using cast nets. Then, samples from their kidneys were cultured on a Rimler Shott agar to isolate Aeromonas spp. Polymerase chain reaction (PCR) was used to confirm this isolation using specific gene primers for species identification. Subsequently, the isolates were tested for their sensitivity to 14 antibiotics using the Kirby–Bauer method, after which the PCR was conducted again to detect resistance genes: sul1, strA-strB, aadA, blaTEM, blaSHV, tetA-tetE, and tetM. Results: From the results, 61 isolates were identified as being from the genus Aeromonas using PCR, of which 28 were Aeromonas jandaei, 19 were Aeromonas veronii, seven were Aeromonas hydrophila, and seven were Aeromonas sobria. Moreover, 8, 12, and 8 of A. jandaei; 4, 3, and 12 of A. veronii; 6, 0, and 1 of A. hydrophila; and 3, 3, and 1 of A. sobria were obtained from Oreochromis spp., C. gariepinus, and P. hypophthalmus, respectively. In addition, the isolates showed the highest level of resistance to ampicillin (100%), followed by streptomycin (59.0%), each kanamycin and nalidixic acid (41.0%), neomycin (36.1%), tetracycline (19.7%), sulfamethoxazole (14.8%), and oxytetracycline (13.1%). Resistance to gentamicin and ciprofloxacin both had the same percentage (9.8%), whereas isolates showed the lowest resistance to norfloxacin (8.2%) and doxycycline (1.6%). Notably, all Aeromonas isolates were susceptible to chloramphenicol and nitrofurantoin. Results also revealed that the multiple antibiotic resistances index of the isolates ranged from 0.07 to 0.64, suggesting that the farmed fish in these areas were introduced to the logged antibiotics indiscriminately and constantly during their cultivation stages. Results also revealed that the sul1 gene was detected in 19.7% of the Aeromonas isolates, whereas the tetracycline resistance genes, tetA and tetE, were detected in 27.9% and 4.9% of the isolates, respectively. However, β-lactam resistance genes, blaTEM and blaSHV, were found in 44.3% and 13.1% of Aeromonas isolates, respectively, whereas strA-strB and aadA genes were found in 3.3% and 13.1% of the isolates, respectively. Conclusion: This study, therefore, calls for continuous surveillance of antibiotic-resistant Aeromonas spp. in cultured freshwater fish to aid disease management and better understand their implications to public health.

Motile aeromonads recovered from tilapia (Oreochromis niloticus) cultured in earthen ponds in the Philippines: assessment of antibiotic susceptibility and multidrug resistance to selected antibiotics

“…This finding is comparable to the data obtained by Son et al (1997) who reported that 43% of the 21 Aeromonas strains recovered from Tilapia mossambica were resistant to erythromycin. Additionally, 64-100% of the motile Aeromonas strains that we examined were resistant to neomycin, coherent to the recent report of Fauzi et al (2021) in A. hydrophila and A. sobria strains isolated from various fish samples such as Oreochromis spp., Clarias gariepinus, and Pangasius hypophthalmus, collected from Kelantan and Terengganu, Malaysia.…”

Molecular Characterization And Antimicrobial Effect Of Some Antibiotics On Aeromonas hydrophila Isolated From Different Sources

“…Furthermore, the existence of these genes may result from secondary resistance mechanisms such as βlactamases or antimicrobial efflux pumps, acquired βlactams resistance from the expression of chromosomal lactamases, or an increase in intrinsic β-lactam resistance, which is improved by an active efflux mechanism or collaboration out of external membrane impermeability (Tayler et al, 2010). Additionally, it is hypothesized that this is due to a high inherent βlactam resistance level, which is boosted by an active efflux mechanism, collaboration through external membrane impermeability, or secondary resistance mechanisms called beta lactamases or antibiotic efflux pumps (Janda and Abbott, 2010;Tayler et al, 2010;Fauzi et al,2021). In the current study, the identification of the sul1gene in all eight A. hydrophila strains that produced 433 bp-amplified products was associated with an increase in trimethoprim and sulphamethoxazole resistance.…”

A Novel Aeromonas popoffii Phage AerP_220 Proposed to Be a Member of a New Tolavirus Genus in the Autographiviridae Family

“…The obtained A. popoffii strain was grown in nutrient broth (NB; Condalab, Madrid, Spain) for 18 h at various temperatures ranging from 10 • C to 37 • C (10,16,20,25,28,31 and 37 • C). In each case, the culture was screened by measurements of OD 600 every three hours.…”

“…Based on the data on Aeromonas spp. natural antimicrobial resistance [8][9][10], susceptibility of A. popoffii CEMTC 4062 to a number of antibiotics was determined. A. popoffii CEMTC 4062 was found to be resistant to beta-lactams (penicillin, ampicillin, ceftazidime, cefepime) and erythromycin; it was sensitive to fluoroquinolones (levofloxacin, ciprofloxacin), and aztreonam.…”

“…Treatment of these infections is complicated by the fact that Aeromonas species are naturally resistant to penicillins, a number of cephalosporins, and erythromycin. Ciprofloxacin is consistently active against Aeromonas strains, but some resistant cases have been reported [8][9][10][11].…”