Diversity and antibiotic profile of Enterobacterales spp. bacteria from Red-naped ibis

Antibiotic resistance in wildlife is an emerging concern, as birds can serve as reservoirs and vectors for resistant bacteria. In this study, we investigated the diversity of bacteria belonging to the Enterobacterales order and their antibiotic resistance patterns in the unexplored Red-naped ibis (Pseudibis papillosa). It is a resident wading bird species in western India, i.e., Udaipur city, Rajasthan. It inhabits a wide range of environments, including urban areas, wetlands, agricultural fields, and fallow lands. Fecal samples (n = 45) were collected and a total of 60 bacterial isolates were analyzed for bacterial diversity and bacteria were characterized using biochemical, molecular, methods. Interestingly, four novel bacterial taxa from this host species were identified, i.e., Enterobacter mori, Enterobacter soli, Citrobacter freundii, and Leclercia adecarboxylata. Notably, E. mori and E. soli were reported for the first time in this bird species globally. Antibiotic susceptibility testing revealed high levels of multidrug resistance, with 40% of isolates resistant to at least three classes of antibiotics. Notably, resistance to clinically important antimicrobials, including the third-generation cephalosporin cefotaxime and reduced susceptibility to the carbapenem imipenem, was observed, raising concerns for spread of antibiotic resistance bacteria. Resistance to linezolid (100%) and rifampicin (100%) was also observed across isolates, consistent with the intrinsic resistance of Gram-negative bacteria to these agents. Our findings reported the presence of antibiotic-resistant bacteria in wild bird species which may contribute to the spread of antibiotic resistance through their fecal deposits and pose a serious risk to the health of humans and wild animals.