Phenotypic Characterisation of Proteus Species Isolated from Different Clinical Samples with Special Reference to Antibiotic Resistance Pattern in a Tertiary Care Centre

Introduction: The Proteus species are vulnerable to cause community-acquired and Healthcare Acquired Infections (HCAI). This organism is grouped under opportunistic pathogen and implicates a wide range of infection in humans. The emergence of antimicrobial resistance in this species is alarming and life threatening.

Aim: To evaluate the prevalence and the resistance pattern of Proteus species isolated from various clinical samples by conventional culture methods.

Materials and Methods: This was a cross-sectional study conducted from May 2020 to April 2021. The study was conducted at SRM Medical College Hospital and Research Centre, Chennai, Tamil Nadu, India, after approval from the Institutional Ethical Committee. Proteus isolates from various clinical samples like wound swab, pus, urine, Cerebrospinal Fluid (CSF), tracheal swabs, endotracheal aspirate, vaginal swabs, blood, body fluids, ear swab, tissue were collected as per standard protocols. The phenotypic characterisation and resistance pattern of Proteus isolates were done by conventional culture methods. The analysis was done using Statistical Package for the Social Sciences (SPSS) software version 24.0.

Results: Out of 100 isolates, the higher number of Proteus species was isolated from pus sample (35%), wound swab (22%) and urine sample (25%). Males were found to have a higher prevalence (65%) of infections by Proteus species than females. Proteus mirabilis was the most common isolated species (89%) in this study. The Extended Spectrum Beta Lactamase (ESBL) producers among Proteus species were found to be 39%, AmpC producers to be 20% and carbapenemase producer 1%. Proteus species had the highest sensitivity to piperacillin tazobactam (100%), tigecycline (100%), meropenem and imipenem (98%) in this study.

Conclusion: It was concluded that there was an increasing occurrence of drug resistance Proteus species. Their resistance is contributed by production of ESBL, AmpC and carbapenemase enzymes. The screening test alone is sufficient for detection of antibiotic resistance. Hence, there is a need for reliable phenotypic confirmatory test to identify the resistance among Proteus species.