Antimicrobial susceptibility patterns of Linezolid-resistant coagulase-negative staphylococci in Pakistan

OBJECTIVE: To determine the antimicrobial resistance pattern in Linezolid-resistant coagulase negative staphylococcus (CoNS) isolates in Pakistan. METHODS: This cross-sectional study was conducted from February and July 2022, at a private laboratory in Lahore, with samples collected from various regions across Pakistan. The study included microbiological samples such as blood and wound specimens, from which 4,153 isolates of CoNS were identified. Of these, only 64 isolates that were both coagulase-negative and Linezolid-resistant were selected for further investigation. The antimicrobial susceptibility patterns of these Linezolid-resistant isolates were analyzed. The antibiotics tested included amikacin, ciprofloxacin, clindamycin, doxycycline, erythromycin, fusidic acid, gentamicin, oxacillin, teicoplanin, trimethoprim-sulfamethoxazole, and vancomycin. Data analysis was performed using SPSS version-22. RESULTS: Among 4153 samples, 64 (1.54%) were Linezolid-resistant CoNS isolates, predominantly from adults (aging 18-59 years) and senior adults (aging >59 years), with a higher prevalence in males (56.3%). Resistance was observed in 51.6% of blood and 48.4% of pus samples. Most isolates were also resistant to teicoplanin (100%), ciprofloxacin (92.2%), oxacillin (89.1%), and fusidic acid (84.4%), while sensitivity was highest for vancomycin (85.9%) and doxycycline (79.7%). Statistically significant differences were noted for all antibiotics except erythromycin. CONCLUSION: Our findings highlight the importance of monitoring the evolution of Linezolid resistance in CoNS as Linezolid resistant isolates also showed high resistance to some other major antimicrobial drugs (e.g. teicoplanin, ciprofloxacin, oxacillin etc.). Linezolid resistance must be closely monitored, especially when frequent and prolonged Linezolid therapy is indicated to implement control measures and reduce the risk of CoNS spreading in the community.