Bacteriology and antibiotic prescription patterns at a Malawian tertiary hospital burns unit

Abstract

Background: Infections are responsible for up to 85% of deaths in patients with burn injuries. Proper management of infections in patients with burns requires knowledge of local microbial landscape and antimicrobial resistance patterns. Most burns units in low to middle income countries lack this data to guide patient management.

Methods and Results: A retrospective audit of adult (≥17 years) patient records admitted between at 1^st June 2007 and May 2017 was conducted at Queen Elizabeth Central Hospital Burns unit in Blantyre Malawi with an index complaint of burn injury. Descriptive statistical analysis was performed to determine antimicrobial prescription patterns, microbial isolates and antimicrobial resistance patterns on 500 patient files that met the inclusion criteria. Cephalosporins and penicillins constituted 237 (72.3%) of the 328 antimicrobial prescriptions given to 212 patients, and prescriptions given to 178 (84%) patients were potentially inappropriate. A total of 102 bacterial isolates were identified; 61 (59.8%) gram positive and 12 (11.8%) not classified taxonomically. Thirty-one (30.4%) isolates were resistant to aminoglycosides and aminocyclitols; seconded by 20 (19.6%) that were resistant to penicillins. Pseudomonas, Staphylococcus and Streptococcus species constituted 13 (36.1%), 9 (25%) and 6 (16.7%) of all resistant bacteria that were isolated, and they were thus the most common bacterial isolates. Drug resistance was more common among gram-negative bacteria 16 (48.8%) versus 20 (26.2%), and a greater proportion of patients (n=20; 74.1%) that had antimicrobial sensitivity testing were affected by drug resistant gram-negative bacteria which appear on the World Health Organization list of priority pathogens.

Conclusions: The result of our preliminary study points towards nosocomial gram-negative bacteria which appear on the World Health Organisations list of priority pathogens as the more common sources of antimicrobial resistance. This scenario is potentially driven by inappropriate antimicrobial prescriptions as well as clinical and laboratory diagnostic imprecision in addition to the universally recognised post burn pathophysiological changes of hypermetabolism and immunosuppression. Improvements in the areas of antimicrobial stewardship, diagnostic capacity and burns related research are needed in order to achieve optimal therapeutic outcomes and resource utilisation.