Retrospective Study of Staphylococcus haemolyticus in Blood Sample and their Susceptibility Pattern in A Tertiary Care Hospital in Dhaka, Bangladesh
Author(s): Rehana Razzak Khan*, Ismet Nigar, SM Ali Ahmed, Sourav Debnath, Sharmeen Ahmed, Chandan Kumar Roy, Abu Naser Ibne Sattar, Sanjida Khandakar Setu, Shaheda Anwar
Staphylococcus haemolyticus is one of the frequently isolated coagulase-negative Staphylococci(CoNS). Though it is considered mostly a skin contaminant, this organism has emerged as an important cause of nosocomial bloodstream infections (BSIs). A high antibiotic resistance profile and biofilm formation of Staphylococcus haemolyticus in comparison to other CoNS is a concern and therapeutic challenge now a days.
Aim: This study aims to observe the distribution of clinically significant Staphylococcus haemolyticus associated with bloodstream infection and to determine their antibiotic susceptibility profile.
Materials and Methods: A retrospective observational study which was conducted in the Department of Microbiology & Immunology, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh, between June 2023 and July 2024. Six thousand, one hundred ninety-nine blood samples were collected in automated blood culture bottle, and the bacterial profile was retrieved using an automated BACT/ALERT 3 D System and BD BACTEC FX continuous monitoring system. The collected blood sample was processed, and the full identification of the organism and antimicrobial susceptibility was conducted by using the VITEK 2 Compact Lab automated system and Kirby Bauer disk diffusion methods per the National Committee for Clinical Laboratory Standards guidelines. Patients with suspected bacteremia with the clinical evidence of infection were included.
Results: A total of 6199 blood samples were collected, of which 519 (8.37%) showed bacterial growth. Among them, number of total isolated CoNS were 52(10.01%). The most prevailing isolate was Staphylococcus haemolyticus (59.61%), followed by Staphylococcus hominis (32.69%), Staphylococcus urealyticus (3.84%), Staphylococcus epidermidis (1.92%) and Staphylococcus saprophyticus (1.92%). High level of resistance was observed to ciprofloxacin (80.65%), followed by erythromycin (67.74%) and cloxacillin (51.61%). None of the isolates exhibited resistance to reserve drugs like vancomycin, linezolid and rifampicin. These isolates showed better susceptibility to amoxicillin (77.42%), cotrimoxazole (74.19%), gentamicin (67.7%). About 9.68% Staphylococcus haemolyticus was detected as methicillin resistant (MRSH) and they were sensitive to vancomycin, linezolid and rifampicin.
Conclusion: This result indicates that the isolated Staphylococcus haemolyticus among CoNS, is increasing, and an update of this isolate's antibiotic-resistance pattern is necessary for timely interventions and better patient outcome- as most of the isolates are considered as contaminant or remain underdiagnosed. These results underscore the implementation of effective infection prevention and control program in hospitals across Bangladesh.