Fig 1.
Sample collection and processing from suspected Aeromonas infected cat fishes.
(a) stinging cat fish samples, where circle indicated infected skin (ulceration and haemorrhage); (b) collection of Intestine (haemorrhagic) and Gill (normal) of stinging cat fish; (c) shark cat fish sample, circle indicated lesion on head region; and (d) collection of intestine and gill (normal appearance) of shark cat fish.
Table 1.
Primers used for the PCR amplification of virulence genes in A. hydrophila isolates.
Table 2.
Morphological and biochemical characterization of A. hydrophila.
Fig 2.
Growth of suspected Aeromonas spp. on different agar media.
(a) TSA (light yellowish creamy smooth colonies); (b) TCBS agar (yellow shin with diameter 2-3 mm); (c) Sheep blood agar (pale white smooth colonies with β-haemolysis).
Fig 3.
Representative picture of PCR amplification detecting Aeromonas hydrophila.
[a] PCR amplification of genus-specific 16S rDNA gene sequence of A. hydrophila; M: 1 kb molecular marker; NC: negative control; Lane 1-10: positive Aeromonas spp. at 953 bp; [b] species-specific 16S rDNA gene-based PCR detection of A. hydrophila; M: 100 bp DNA ladder; NC: negative control; Lane 1-9: positive A. hydrophila at 625 bp amplicon size.
Table 3.
Occurrence of virulence genes of A. hydrophila in stinging catfish and shark catfish of Trishal and Muktagachha upazila.
Fig 4.
PCR amplification of virulence genes.
M: 1 kb ladder; NC: negative control, [a]. elastase (ahyB) gene; (1-10) lane with 513 bp, [b]. heat labile enterotoxin (alt) gene; (1-10) lane at 442 bp, [c]. aerolysin A (aerA) gene; (3,4,8) lane negative and (1,2,5,6,7,9,10) lane positive with 431 bp, [d]. haemolysin A (hlyA); lane 5,8,9 negative and (1,2,3,4,6,7) lane positive with 597 bp, [e]. cytotoxic enterotoxin (act); lane 3,4,6,8 negative and rest of the lane positive with 232 bp, [f]. cytotoxic heat stable enterotoxin (ast); lane 1,2,4,6,9 positive 331 bp, and lane 3,5,7,8 negative [g]. serine protease (ser); lane (1-10) positive with 350 bp, [h]. lipase (lip); lane 5,8 negative and rest of positive with 382 bp, [i]. glycerophospholipid-cholesterol acyl transferase (gcat); lane 2,3,9,10 negative and lane 1,4,5,6,7,8 positive with 237 bp, [j]. type secretion (ascV); lane 1,3,5,7,9 positive 807 bp and lane 2,4,6,8,10 negatives, [k]. haemolysin-homolog (asa1); lane (1-6) positive 249 bp.
Fig 5.
Prevalence of virulence genes in Trishal and Muktagachha.
Table 4.
The antibiotic susceptibility profile of A. hydrophila isolates.
Fig 6.
Heatmap showing antibiotic susceptibility pattern of A. hydrophila isolates.
P: Penicillin G; AMP: Ampicillin; AML: Amoxicillin; CE: Cephradine; CXM: Cefuroxime; CRO: Ceftriaxone; MEM: Meropenem; ATM: Aztreonam; S: Streptomycin; K: Kanamycin; CN: Gentamicin, E: Erythromycin; AZM: Azithromycin; COT: Cotrimoxazole; TE: Tetracycline; C: Chloramphenicol; FFC: Florfenicol; NA: Nalidixic acid; CIP: Ciprofloxacin; LEV: Levofloxacin.
Table 5.
Isolate-wise MDR, MAR index analysis and virulence gene distribution of the A. hydrophila isolates.
Table 6.
Association between phenotypic resistance and virulence factors (haemolysin and cytotoxic type) in A. hydrophila isolates.
Table 7.
Association between phenotypic resistance and virulence factors (responsible for tissue destruction and invasion) in A. hydrophila isolates.