Detection of virulence genes and antimicrobial resistance genes in staphylococci isolated at Malamulo hospital in Malawi.
Date
2022
Authors
Taika, Wilfred
Journal Title
Journal ISSN
Volume Title
Publisher
The University of Zambia
Abstract
Staphylococci associated morbidities and mortalities have been on the rise in Malawi due to paucity of molecular AMR surveillance data critical for improved patient care. This retrospective laboratory-based study was conducted at Malamulo Hospital, a sentinel AMR surveillance site in Malawi under Fleming fund. The study aimed at detecting selected virulence and AMR genes in 36 Staphylococci bacteria stocked between December 2021 and May 2022 for a molecular AMR surveillance. Sample source types included blood (16), urine (14), pus (three), skin wedge (one), pleural fluid (one), and ascitic fluid (one). Patients age categories recorded were 12 paediatrics, 19 young adults, two middle aged adults and three elderly adults. The nuc, spa and coa genes were used to detect and identify S. aureus species. Disc diffusion susceptibility test was used to determine antimicrobial susceptibility levels. PCR was performed to detect antimicrobial resistance genes (mecA, ermA, ermB, ermC, tetK, tetL, tetM and tetO) and virulence genes (PVL (lukS-PV and lukF-PV), splA, splB, splC, splD, splE, and splF) respectively. The spa gene was sequenced after which Spa typing was also done. Descriptive statistics were used for analysis. From the sample source types, the proportion of PCR confirmed S. aureus was 38.9% (14/36) and 61.1% (22/36) were other Staphylococci. Noteworthy disc diffusion antimicrobial resistance levels in the study were against trimethoprim/sulfathomexazole (50%) and MDR-MRSA (three S. aureus isolates). Antimicrobial resistance genes detected included tetK (57.1%), mecA (14.3%) and tetM (7.1%). The splA, splB, splC, splD, splE and splF genes were detected in 86% (12/14) of confirmed S. aureus isolates. PVL (lukS-PV and lukF-PV) gene was detected in four S. aureus isolates. Spa type t941 was common at 33.3% (3/9) and an unknown spa type was detected. These findings indicate probable life-threatening infections caused by virulent, multidrug and methicillin resistant S. aureus of several spa lineages among patients at Malamulo Hospital. Hence a call for molecular epidemiology and molecular characterization studies preferably using whole genome sequencing tools at Malamulo Hospital in Malawi for more insights into the S. aureus infections.
Description
Thesis of Master of Science in One Health Laboratory Diagnostics Sciences