Bacteriological profile and antimicrobial resistance patterns of bloodstream infections among adult sepsis patients at Ndola Teaching Hospital

Introduction Bloodstream infections (BSIs) are a major cause of morbidity and mortality worldwide, particularly in low- and middle-income countries where antimicrobial resistance (AMR) is increasing. Understanding local bacteriological profiles and antibiotic susceptibility patterns is essential for guiding effective empirical therapy, enabling clinicians to select the most appropriate antibiotics while patients await culture results, thereby reducing the risk of treatment failure, limiting the unnecessary use of broad-spectrum antibiotics, and slowing the progression of AMR. This study aimed to determine the bacteriological profile and antibiogram of blood culture isolates among adult patients with suspected sepsis at Ndola Teaching Hospital, Zambia. Methods A hospital-based cross-sectional study was conducted among adult in-patients (≥ 18 years) with suspected sepsis. Written informed consent was obtained from all participants prior to enrolment. Blood samples were collected aseptically and cultured using standard microbiological techniques. Bacterial identification and antimicrobial susceptibility testing were performed using conventional biochemical methods and the Kirby–Bauer disc diffusion method in accordance with Clinical and Laboratory Standards Institute (CLSI) guidelines. Data were analyzed using SPSS version 22. For the purposes of this study, a “culture-confirmed bloodstream infection” was defined as the recovery of a clinically significant bacterial isolate from a blood culture in a patient with signs and symptoms consistent with sepsis, as determined by the attending clinician in consultation with the microbiology laboratory. Results A total of 570 participants were included, of whom 239 (41.9%) had positive blood cultures. The majority (146/239; 61.1%) of the isolates were Gram positive, with coagulase-negative staphylococci (CoNS) (48/239; 20.1%) and Staphylococcus aureus (24/239; 10.0%) being the most prevalent. Among Gram-negative organisms, Escherichia coli (17/239; 7.1%), Proteus mirabilis (14/239; 5.9%), and Pseudomonas aeruginosa (14/239; 5.9%) were the leading isolates. High levels of antimicrobial resistance were observed among both Gram-positive and Gram-negative bacteria. Gram-positive isolates showed high resistance to penicillin (64/76; 84.2%) and moderate resistance to erythromycin (32/70; 45.7%), while maintaining full susceptibility to vancomycin (59/59; 100.0%) and linezolid (54/54; 100%). Gram-negative isolates demonstrated high resistance to ampicillin (73/82; 89.0%) and third-generation cephalosporins, whereas higher susceptibility was observed for meropenem (53/58; 91.4%), amikacin (57/66; 86.4%), and piperacillin–tazobactam (50/62; 80.6%). Conclusions This study revealed a high burden of bloodstream infections and substantial levels of antimicrobial resistance among patients treated at Ndola Teaching Hospital. The predominance of resistant pathogens highlights the important need for strengthened antimicrobial stewardship, routine Laboratory surveillance, and improved infection prevention and control practices to guide appropriate treatment and reduce the impact of local AMR. However, these findings require confirmation in larger, multicentre studies to inform broader policy and practice.