Exploring the antimicrobial resistance profiles of WHO critical priority list bacterial strains
Date
2019-12-23
Journal Title
Journal ISSN
Volume Title
Publisher
BMC (part of Springer Nature)
Abstract
Background: The antimicrobial resistance of clinical, environmental and control strains of the WHO “Priority 1:
Critical group” organisms, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae and Pseudomonas
aeruginosa to various classes of antibiotics, colistin and surfactin (biosurfactant) was determined.
Methods: Acinetobacter baumannii was isolated from environmental samples and antibiotic resistance profiling was
performed to classify the test organisms [A. baumannii (n = 6), P. aeruginosa (n = 5), E. coli (n = 7) and K. pneumoniae
(n = 7)] as multidrug resistant (MDR) or extreme drug resistant (XDR). All the bacterial isolates (n = 25) were screened
for colistin resistance and the mobilised colistin resistance (mcr) genes. Biosurfactants produced by Bacillus
amyloliquefaciens ST34 were solvent extracted and characterised using ultra-performance liquid chromatography
(UPLC) coupled to electrospray ionisation mass spectrometry (ESI–MS). The susceptibility of strains, exhibiting antibiotic
and colistin resistance, to the crude surfactin extract (cell-free supernatant) was then determined.
Results: Antibiotic resistance profiling classified four A. baumannii (67%), one K. pneumoniae (15%) and one P.
aeruginosa (20%) isolate as XDR, with one E. coli (15%) and three K. pneumoniae (43%) strains classified as MDR. Many of
the isolates [A. baumannii (25%), E. coli (80%), K. pneumoniae (100%) and P. aeruginosa (100%)] exhibited colistin
resistance [minimum inhibitory concentrations (MICs) ≥ 4mg/L]; however, only one E. coli strain isolated from a clinical
environment harboured the mcr-1 gene. UPLC-MS analysis then indicated that the B. amyloliquefaciens ST34 produced
C13–16 surfactin analogues, which were identified as Srf1 to Srf5. The crude surfactin extract (10.00 mg/mL) retained
antimicrobial activity (100%) against the MDR, XDR and colistin resistant A. baumannii, P. aeruginosa, E. coli and K.
pneumoniae strains.
Conclusion: Clinical, environmental and control strains of A. baumannii, P. aeruginosa, E. coli and K. pneumoniae
exhibiting MDR and XDR profiles and colistin resistance, were susceptible to surfactin analogues, confirming that this
lipopeptide shows promise for application in clinical settings.
Description
CITATION: Havenga, B., et al. 2019. Exploring the antimicrobial resistance profiles of WHO critical priority list bacterial strains. BMC Microbiology, 19:303, doi:10.1186/s12866-019-1687-0.
The original publication is available at https://bmcmicrobiol.biomedcentral.com
Publication of this article was funded by the Stellenbosch University Open Access Fund.
The original publication is available at https://bmcmicrobiol.biomedcentral.com
Publication of this article was funded by the Stellenbosch University Open Access Fund.
Keywords
Microorganisms -- Effect of antibiotics on, Anti-infective agents -- Control, Bacteria -- Control, Pseudomonas aeruginosa -- Effect of drugs on, Antibiotics -- Analysis, Antibiotics -- Testing, Surfactin -- Multidrug resistance
Citation
Havenga, B., et al. 2019. Exploring the antimicrobial resistance profiles of WHO critical priority list bacterial strains. BMC Microbiology, 19:303, doi:10.1186/s12866-019-1687-0