Microbiological profile of organisms causing bloodstream infections between 2004 and 2016 in a tertiary hospital Limpopo province South Africa

Abstract

Background: Nosocomial bloodstream infections constitute a significant public health problem and may be an important cause of morbidity and mortality in patients who are hospitalized. The presence of living microorganisms in the blood of a patient is usually indicative of a serious invasive infection requiring antimicrobial therapy. Mortality associated with bloodstream infections may range from 20 to 50% and depends on several factors, including pathogen and host factors. Many septic episodes are nosocomial and may be due to microorganisms with increased antimicrobial resistance. Aim: This study describes the microbiological profile of the organisms, and their resistance to antibiotics, causing bloodstream infections in patients in a tertiary hospital in Limpopo between 2004 to 2006 and 2014 to 2016. Methods: This was a retrospective laboratory-based serial cross-sectional study of 219 cultures in 2004 to 2006 73 of which were positive and 1095 cultures in 2014 to 2016 298 of which were positive. Data, including patient demographics (age, gender), microbial species (as recorded in the blood culture reports) and the antibiograms of isolated microorganisms, was collected and analysed. Results: 371 blood culture results which were culture positive were analysed. Coagulase negative staphylococci 190 (51.2%), Acinetobacter baumannii 14 (4%), Klebsiella pneumonia 44 (11.9%), Enterococcus spp 23 (6.2%). Enterobacter spp 19 (5.1%), Staphylococcus aureus 21 (7.3%), and Escherichia coli 14 (3.8%) were predominant. The constitution of bacteria cultures isolated where gram status was known, was gram-positive 262 (70.6%) and gram-negative 106 (28.6%). Among the S. aureus isolates, extended-spectrum beta lactamase (ESBL) positivity was 27 (7.3%). The microorganisms exhibited a level of resistance against the following antimicrobials: (colistin, imipenem, linezolid, meropenem and vancomycin). Conclusions: There was an increase in the numbers of tests, and hence the numbers of isolates, between the two study periods. The study demonstrated that there was a less than 3% drug resistance level, against antibiotics tested for, in both time periods. There was no clinically significant change in the resistance levels between the first and second study periods.