Profile of Aerobic Bacteria and Their Antimicrobial Susceptibility Patterns in Pus Samples and Wound Swabs at a Tertiary Care Hospital in Punjab, India

Introduction: Skin disruptions exposing subcutaneous tissue provide a moist, warm, and nutrient-rich environment that is conducive to microbial growth. Wound infections can lead to sepsis, limb loss, prolonged hospital stays, increased healthcare costs, and significant morbidity and mortality worldwide. Therefore, this study aimed to identify the aerobic bacterial pathogens responsible for wound infections and determine their antimicrobial susceptibility patterns, thereby providing valuable guidance for clinicians to inform the selection of empirical antimicrobial therapy. Methods: This retrospective study included ۱۳۸۸ wound samples analyzed at the Department of Microbiology, Sri Guru Ram Das Institute, Amritsar, Punjab, India, from July ۲۰۲۱ to June ۲۰۲۲. All specimens underwent bacterial culture and antimicrobial susceptibility testing using standard microbiological techniques, including Gram staining. Identification and susceptibility testing were performed using the VITEK ۲ automated system (bioMérieux, Marcy-l’Étoile, France). Minimum inhibitory concentration (MIC) results were interpreted as susceptible, intermediate, or resistant, based on Clinical and Laboratory Standards Institute (CLSI) guidelines. Statistical analyses were performed using SPSS version ۲۶.۰ (IBM Corp., Armonk, NY, USA). Chi-square tests were applied for comparing categorical variables (gender and culture positivity). A P-value ≤ ۰.۰۵ was considered statistically significant. Results: Out of ۱۳۸۸ wound samples cultured, ۷۰۷ (۵۰.۹%) showed no bacterial growth, and ۶۸۱ (۴۹.۱%) were culture-positive, of which ۶۱۸ were monomicrobial and ۶۳ were polymicrobial. A total of ۷۴۴ bacterial isolates were obtained: ۶۰۲ (۸۱%) were Gram-negative and ۱۴۲ (۱۹%) were Gram-positive. The most common isolates were Escherichia coli (۲۹%, n=۲۱۹), followed by Staphylococcus aureus and Klebsiella pneumoniae (۱۷%, n=۱۲۸ each). Enterobacterales isolates were most susceptible to amikacin (۶۷%), followed by tigecycline (۶۱%) and meropenem (۵۷%), but showed low susceptibility to amoxicillin-clavulanate and ampicillin. Pseudomonas aeruginosa exhibited its highest susceptibility to carbapenems, whereas Acinetobacter baumannii was largely resistant, with the highest susceptibility noted for tigecycline (۲۵%). Gram-positive isolates were highly susceptible to linezolid (۹۱%) and tigecycline (۹۱%). Conclusion: This study details the local pathogen profile from wound infections and their antimicrobial susceptibility patterns, providing critical guidance for empirical therapy and antimicrobial stewardship efforts at our institution.

کلیدواژه ها:

Wound infection ، Antimicrobial susceptibility testing ، Escherichia coli ، Staphylococcus aureus ، Klebsiella pneumoniae ، carbapenems