Isolation and Antimicrobial Susceptibility Testing of Haemophilus influenzae in a Tertiary Care Hospital, a 6-Year Study (2016 to 2021)

Objective: To determine the prevalence and antimicrobial susceptibility of Haemophilus influenzae at Taksin Hospital. Materials and Methods: The susceptibilities of clinical isolates to six antimicrobial agents, ampicillin (AP), cefuroxime (CXM), cefotaxime (CTX), ciprofloxacin (CIP), trimethoprim-sulfamethoxazole (SXT), and meropenem (MEM), between 2016 and 2021 were evaluated by the standard disk diffusion method. Results: One hundred thirty-eight H. influenzae clinical isolates were found in different patients. There were 63.04% male patients. The ages of patients ranged from two months to 93 years old (mean±SD: 65.67±20.58). H. influenzae was mostly found in patients older than 50 (60.14%) years old. In children, H. influenzae was mostly found in patients younger than 1 to 10 (16.67%) years old. Unduplicated H. influenzae from different patients were isolated from the sputum (71.01%), blood (11.59%), pus from eyes (10.14%), and urethra (2.90%). H. influenzae demonstrated 100% susceptibility to CTX, CIP, and MEM, but less susceptibility to CXM (93.48%), AP (49.28%), and SXT (53.62%). Conclusion: The present study results suggested the importance of monitoring the prevalence of H. influenzae at a hospital in Bangkok. The antibiogram of susceptibility helps provide guidelines for clinician to consider empirical treatment. Keywords: Haemophilus influenzae; Drug resistance, Thailand