Investigation of Gram-Negative Bacilli Bacteraemia in a Tertiary Hospital in Nigeria: Epidemiology and Antimicrobial Susceptibility Pattern

Background: The re-emergence of gram-negative bacilli (GNB) as the predominant cause of bacteraemia remains a major concern, given the increasing trend of antimicrobial resistance among this group of organisms. Prompt and effective empirical antibiotic treatment is vital for preventing adverse outcomes; therefore, a good knowledge of the local bacteria profile is required. Objective: This study was designed to aid the establishment of local antibiogram and empirical treatment for GNB bacteremia in patients referred to the University of Port Harcourt Teaching Hospital (UPTH), Nigeria. Materials and Methods: A total of 230 blood samples were obtained from inpatients in different units/departments from December 2017 to November 2018. The blood cultures were processed using BACTEC 9060 automated blood culture system, and the isolates were identified using MICROBACT 12E identification kits (Oxoid, UK) at the microbiology laboratory of UPTH. Susceptibility and resistance tests were done according to CLSI guidelines. Relevant information was obtained from the laboratory request forms and patients’ clinical files. Results: The prevalence of GNB in the study was 28.9% (71/246). The distribution of GNB bacteraemia was as follows: surgical unit (26.8%), special care baby unit (SCBU) (23.9%), intensive care unit (ICU) (21.1%), and paediatric ward (8.5%). The most common source of bacteraemia was pneumonia (35.2%) followed by puerperal sepsis (15.1%) and urinary tract infection (UTI) (15.1%). Klebsiella pneumoniae was the most frequently isolated gram-negative bacillus (26.6%). The overall resistance rate of extended spectrum lactamase producing Enterobacteriaceae (ESBL) producers, carbapenemase producers, and multi-drug resistant (MDR) organisms was 32.4%, with Acinetobacter baumannii (50%) and Pseudomonas aeruginosa (27.3%) exhibiting the highest level of resistance to carbapenems. Conclusion: This study showed a high MDR rate among GNB causing bacteraemia in patients at UPTH. An urgent review of the current antimicrobial prescription policy and infection control measures is recommended.