Retrospective Study of Bacterial Profile in Wound Swab and Their Susceptibility Pattern in A Tertiary Care Hospital in Dhaka, Bangladesh

Author(s): SM Ali Ahmed, Ahmed Abu Saleh, Ismet Nigar, Rehana Razzak Khan, Sharmeen Ahmed, Abu Naser Ibne Sattar, Chandan Kumar Roy, Sanjida Khondakar Setu, Shaheda Anwar

Increased antibiotic resistance of bacterial isolates from wound infections is a major therapeutic challenge. This study aimed to identify bacterial isolates associated with wound infection and to determine their antimicrobial susceptibility profile. This retrospective study was conducted in the Department of Microbiology, Bangabandhu Sheikh Mujib Medical University, Dhaka, between January 2023 and December 2023. One thousand six hundred thirty wound swabs were collected, and the bacteriological profile was retrieved. The collected wound swab was processed and cultured using standard techniques in a medical microbiology laboratory. The isolated bacteria were identified by colony morphology, Gram staining, and biochemical reactions. Antibiotic susceptibility testing of the detected isolates was performed using the Kirby Bauer disc diffusion techniques as per the National Committee for Clinical Laboratory Standards guidelines. All retrieved profiles were initially recorded into an Excel Sheet and analyzed using SPSS, version 23. About 1630 wound swab samples were collected, of which 786(48.22%) showed bacterial growth. Out of 786 bacterial growth, the majority (53.94%) of culture-positive cases were in the age group 21-40 years, and 60.56% were male. Of the 786-culture growth, 645 (82.06%) were gram-negative bacteria, and 141(17.93%) were gram-positive. Pseudomonas spp. (32.69%) was the prevailing isolate, followed by Klebsiella spp (29.26%), Staphylococcus aureus (17.93%), Acinetobacter spp (11.57%), Escherichia coli (5.21%), Proteus spp (2.16%), Enterobacter spp (1.01%) and Serratia spp (0.12%). Among gram-negative isolates, most Pseudomonas spp were resistant to ciprofloxacin (83.65%), followed by gentamicin (65.75%) and ceftazidime (61.08%). The highest sensitivity was exhibited for colistin, which demonstrated 10.11% resistance among Pseudomonas spp, and the least resistance to meropenem (45.91%), piperacillin+tazobactam (47.85%) and amikacin 47.85%. Among gram-positive isolates, Staphylococcus aureus was susceptible to linezolid (100%), vancomycin (100%), cotrimoxazole (59.58%), and gentamicin (58.86%). However, they exhibited resistance to amoxicillin (84.39%), cephradine (73.73%), ciprofloxacin (82.26%), and erythromycin (78.72%). Isolated Klebsiella spp were mostly resistant to amoxicillin (94.34%), followed by cefuroxime (80%) and cefotaxime (75.65%). Most E. coli was resistant to amoxicillin (95.12%) cefotaxime (75.60%) and ceftriaxone (70.73%) All the E. coli isolates were sensitive to colistin. These results indicate that the isolation rate from wound infection was high and the increasing trend of antibiotic resistance in both gram-positive and gram-negative bacteria is alarming, which may lead to treatment failure.