Bacteriological Profile and Antibiogram of Culture-Confirmed Orthopaedic Wound Infections in a Tertiary Care Hospital.

Introduction Orthopaedic infections are one of the common causes of high morbidity and are challenging complications to treat. It includes non-healing ulcers, osteomyelitis, diabetic foot, compound fractures, and SSIs (surgical site infections), such as implant-associated infections and prosthetic joint infections. The most commonly associated organisms include Staphylococcus aureus, Escherichia coli, Pseudomonas, Proteus, and Enterococcus species. However, most of the bacterial isolates exhibit resistance to commonly used antibiotics. Moreover, the spectrum of microbial flora and the antibiotic susceptibility pattern may vary across regions. Therefore, the present study was undertaken with the primary objective of identifying the bacteria isolated from pus samples received for culture in the microbiology laboratory from the Department of Orthopaedics, Tezpur Medical College and Hospital, and determining the antimicrobial susceptibility pattern among the isolated bacteria. The secondary objectives were to analyze the distribution of culture-positive cases by age and wound aetiology and to report MRSA (methicillin-resistant Staphylococcus aureus) prevalence among the isolates. Materials and methods This hospital-based retrospective study was conducted between January 2023 and December 2023. A total of 76 culture-positive pus samples obtained from orthopaedic wound infections were included in the study. The samples were subjected to culture according to standard microbiological procedures and were identified using conventional biochemical tests. Antibiotic susceptibility testing was performed using the Kirby-Bauer disk diffusion method and interpreted according to the Clinical and Laboratory Standards Institute (CLSI) 2023 guidelines. Data were retrieved from laboratory records, test requisition forms, and hospital records. Results Of the 76 culture-positive pus samples, most of the positive samples were from the 21-40 age group and from male patients. The majority of the positive cultures were from compound fractures. Although Gram-negative bacilli constitute an overall large proportion, the most common isolate in the present study was Staphylococcus aureus (32, 42.1%). MRSA accounts for 3/32 (9.4%) among the Staphylococcus aureus isolates. Overall, the Gram-positive bacteria demonstrated higher susceptibility to linezolid and levofloxacin, whereas the Gram-negative bacteria showed good susceptibility to aztreonam, carbapenems (imipenem and meropenem), and piperacillin/tazobactam. Conclusion The study highlights the diverse bacterial aetiology of orthopaedic wound infections, with Staphylococcus aureus being the most predominant organism. It provides insight into the need for periodic surveillance to determine the local bacterial profile and its antibiogram to initiate effective empirical therapy and optimize patient outcomes.