Evaluation of antimicrobial pattern of difficult-to-treat resistant Gram negative bacteria from pus samples in a tertiary care setting

Skin and skin structure infections are one of the leading causes of difficult to treat infections. Knowledge about antimicrobial susceptibility and resistance patterns of the isolates yielded from pus specimens will help in efficient and effective management of patients. The aim of our study was to determine the aerobic bacteriological profile from various types of skin and skin structure infections and the susceptibility pattern of difficult-to-treat resistant Gram negative bacteria isolated from pus specimens. This was a retrospective study conducted in Pak Emirates Military Hospital department of microbiology, Army Medical College (National University of Medical Sciences) Rawalpindi. Data of 1,250 pus specimens from January 2023 to December 2023 was retrieved from hospital management system. Pus was processed according to standard microbiological procedure and antimicrobial susceptibility was determined following Clinical and Laboratory Standards Institute 2023.Data was analyzed using statistical package for social sciences version 26 and p value was calculated. Descriptive factors (frequencies, percentage) were calculated for the socio demographic characteristics and antibiotic susceptibility was determined. P value of less than or equal to 0.05 was taken as significant. A total of 1,250 pus specimens were received during one year. Out of these 416 (33.2%) were Gram negative rods and 356 (28.4%) were Gram positive cocci. The most frequently isolated organism was Escherichia coli 156(30.3%) followed by Klebsiella pneumoniae and Pseudomonas aeruginosa. Acinetobacter baumannii emerged as the most resistant pathogen. It was resistant to all antimicrobials except colistin and tigecycline. This study has enabled us to determine various types of Gram negative rods present in pus specimens, as well as their sensitivity for different antibiotics. This information will be used to create our institutional antibiogram, which will guide clinicians in making valuable treatment decisions. Additionally, this study highlights the importance of effective infection control and prevention practices in a large hospital setting, which can help prevent antimicrobial resistance and promote optimal patient care.