Antimicrobial susceptibility profiles of clinically important bacterial pathogens at the Kamuzu Central Hospital in Lilongwe, Malawi

Antimicrobial susceptibility profiles of clinically important bacterial pathogens at the Kamuzu Central Hospital in Lilongwe, Malawi

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Faheema E Choonara1,2,3, Bjørg C. Haldorsen4, Isaac Ndhlovu2, Osborne Saulosi2, Tarsizio Maida2, Fanuel Lampiao3, Gunnar S. Simonsen4,5, Sabiha Y. Essack1, and Arnfinn Sundsfjord4,5

  1. Antimicrobial Research Unit, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
  2. Microbiology Laboratory, Kamuzu Central Hospital, Lilongwe, Malawi.
  3. Africa Centre of Excellence in Public Health and Herbal Medicine, College of Medicine, University of Malawi, Blantyre, Malawi.
  4. Department of Microbiology and Infection Control, Norwegian National Advisory Unit on Detection of Antimicrobial Resistance (K-res), University Hospital of North Norway, Tromsø, Norway.
  5. Research Group for Host-Microbe Interactions, Department of Medical Biology, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway

*Corresponding Authors: Faheema Choonara: faheemachoonara@yahoo.co.uk; Arnfinn Sundsfjord: Arnfinn.sundsfjord@uit.no

Abstract
Background
The aim of this prospective study was to ascertain antimicrobial resistance (AMR) in clinical bacterial pathogens from in-hospital adult patients at a tertiary hospital in Lilongwe, Malawi.
Methods
Clinical specimens (blood culture, pus, urine and cerebrospinal fluid) collected during June to December 2017 were examined for bacterial growth in standard aerobic conditions. One specimen per patient was included. Antimicrobial susceptibility testing (AST) was performed using the disk diffusion method and interpreted according to EUCAST guidelines.
Results
A total of 694 specimens were collected during the study period, of which 336 (48%) specimen yielded visible bacterial growth. Of the 336 specimens, a total of 411 phenotypically different isolates were recovered. Of the 411 isolates, 84 isolates (20%) were excluded and the remaining 327 (80%) were further characterised. The characterised isolates were identified as ESKAPE pathogens (n=195/327; 60%), Escherichia coli (n=92/327; 28%), Proteus mirabilis (n=33/327; 10) or Salmonella spp. (n=7/327; 2%) and were included for further analysis. The excluded isolates (n=84) comprised of coagulase-negative staphylococci (n=25), streptococci (n=33), and low-prevalence Gram-negative bacilli (n=26). E. coli (n=92; 28%) and S. aureus (n=86; 26%) were the most dominant species. A multidrug resistant (MDR) extended spectrum β- lactamase (ESBL)-positive phenotype was detected in Klebsiella pneumoniae (n=20/29; 69%) and E.
coli (n=49/92; 53%). One third of the Pseudomonas aeruginosa isolates were resistant to meropenem (MEM), but did not appear to be carbapenemase-producers. Methicillin resistant Staphylococcus aureus (MRSA) was molecularly confirmed in 10.5% of S. aureus (n=9/86).
Conclusion
The high proportion of the MDR ESBL-phenotype in clinical isolates of Enterobacterales, strongly limits antimicrobial treatment options and has consequences for empirical and targeted antimicrobial treatment as well as clinical microbiology services and hospital infection control. There is need for a continuous surveillance and an antimicrobial stewardship (AMS) program to contain and prevent the spread of AMR.
Keywords; ESKAPE, antimicrobial resistance, ESBL, AmpC

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