Clinical profile and antimicrobial resistance pattern of Morganella morganii isolates from a tertiary care hospital in North India

BACKGROUND: Morganella morganii is an uncommon member of the order Enterobacterales that is increasingly recognized as an opportunistic pathogen, but systematic data from India remain limited. This study determined the isolation frequency, clinical profile and antimicrobial resistance pattern of M. morganii at a tertiary care hospital in North India. METHODS: In this retrospective observational study 30,124 clinical specimens received between January 2023 and December 2025 were processed by standard microbiological methods. Isolates were identified by conventional biochemical tests and confirmed on the VITEK 2 system. Susceptibility to each agent was determined either by Kirby-Bauer disc diffusion or by the VITEK 2 system and all results were re-interpreted according to guidelines of CLSI M100 (35th edition). Only the first isolate per patient was included. RESULTS: Thirty-one M. morganii isolates were recovered, giving an isolation frequency of 0.10% (95% CI: 0.07-0.15%) among all specimens processed. Twenty isolates (64.5%) were from inpatients and 11 (35.5%) from outpatients. Orthopedics, Surgery and Otorhinolaryngology contributed the largest numbers, and pus was the commonest specimen type (14; 45.2%). Just over half the patients were aged over 50 years (16/31; 51.6%), and males predominated (20/31; 64.5%). Resistance was high to cotrimoxazole, fluoroquinolones and third-generation cephalosporins, while aminoglycosides retained relatively good activity; apparent resistance to imipenem exceeded that to ertapenem and meropenem. Nineteen isolates (61.3%) were multidrug-resistant. XDR and PDR status could not be reliably assessed, because susceptibility testing did not cover the full set of antimicrobial categories applicable to the species. CONCLUSION: M. morganii was isolated infrequently but showed clinically relevant multidrug resistance, supporting the importance of accurate identification, susceptibility-guided therapy and continued surveillance. Because this was a retrospective analysis without molecular characterization, the resistance mechanisms underlying the observed phenotypes were not investigated.