Microbial Trends and their Drug Resistance Responsible for Bloodstream Infections in a Superspeciality Transplant Hospital

Background & Objective: Bloodstream infections (BSIs) are critical healthcare-associated infections that lead to high morbidity and mortality, requiring rapid diagnosis and effective antimicrobial treatment. The increasing prevalence of multidrug-resistant organisms (MDROs) exacerbates this issue, particularly in developing countries. The purpose of this study is to assess the bacteriological profile and antimicrobial susceptibility trends of BSIs to establish an antibiogram for effective empirical treatment.

Materials and Methods: This study was conducted retrospectively on 3,300 blood culture samples from a multispecialty hospital over 15 months. Cultures were performed using Bactec FX and identification and antibiotic susceptibility determined by Vitek2 and Kirby-Bauer methods following CLSI guidelines.

Results: Overall, the positivity rate was (14.3%) with 473 isolates: (400 bacterial and 73 fungal). Gram-negative bacteria were predominant, led by Klebsiella pneumoniae (113 isolates) and Escherichia coli (100 isolates). Among the Gram-negative bacteria, antimicrobial susceptibility was found to be low for Cephalosporins (21%sensitivity) and Fluoroquinolones (19.3% sensitivity), with moderate susceptibility to Carbapenems (51.3%). Sensitivity was high for Colistin (98.9%), Amikacin (91.05%), Tigecycline (100%), Fosfomycin (100%) and Ceftazidime-avibactum Aztreonam (97.7%). Among Gram-positive bacteria, Coagulase-negative Staphylococcal Species (CONS) and Staphylococcus aureus were the most common. The overall sensitivity of Gram-positive bacteria to antibiotics tested was high compared to the Gram-negative bacteria. Sensitivity to antibiotics such as Linezolid was found to be 94.5% and Vancomycin was found to be 93.5%.

Conclusion: The high incidence of MDROs especially among the Gram-negative bacteria highlights the need for continuous monitoring and antibiotic stewardship programs. Empirical therapy must consider local resistance patterns, and a multidisciplinary approach is essential to mitigate antimicrobial resistance.