Vol. 11, Issue 12 (2022)

Aim: This study was carried out to determine the prevalence and multidrug resistance phenotypes of Aeromonas species in raw milk collected from urban and peri urban areas of Navsari city of South Gujarat.

Methods: A total of 210 samples, contained 70 raw milk each of cow, buffalo, and goat milk were collected using random sampling methods and analyzed as per standard microbiological procedures, Recovered 44 isolates identified and confirmed by targeting 16srRNA gene as Aeromonas. Additionally, isolates were subjected to antibiogram assay using 12 selected antibiotics by agar disc diffusion method.

Result: The out of 210 raw milk samples examined, 44 samples were positive for Aeromonas with a prevalence of 21%, and each isolates amplified the 16S rRNA gene unique to the Aeromonas genus. Further 33 (15.7%) isolates amplified the 16Sr RNA gene that was unique to the A. hydrophila, while the remaining 11 (5.23%) amplified isolates were identified as the A. caviae species. All the 44 isolates tested for antibiotic sensitivity showed the highest levels of susceptibility to chloramphenicol (95.5%), ciprofloxacin, and nalidixic acid (90% each), next to ofloxacin (86%) and ceftriaxone (81%). Also, isolates were moderately sensitive to co-trimoxazole (75%) and trimethoprim (69%). Isolates exhibited moderate to complete resistance phenotypic pattern to sulfamethizole (30%), gentamicin (52%), tetracycline (40%), ampicillin (52%), and highly resistance to penicillin (100%), each isolate displayed a MAR index between 0.08 and 0.5.

Conclusion: This study advocates sensible and rational use of the antibiotics in the field, so as to safe guard nature and protect human health and the environment in the long run.