Available online 20 August 2022, 106663
Highlights•mrkA expression is related to biofilm production.
•K. pneumoniae HR clones are frequently strong biofilm-producers.
•Biofilm viability is maintained for longer at 25°C than at 37°C.
•Povidone iodine effectively reduces biofilm formation
AbstractBackgroundThe role of mrkA adhesin expression, biofilm production, biofilm viability and biocides in the biofilms of carbapenemase-producing K. pneumoniae isolates was investigated.
MethodsSeventeen isolates representing different sequence types and carbapenemases were investigated. mrkA expression was determined by real-time RT-PCR. Biofilm production (25°C and 37°C, with and without humidity) was determined by the crystal violet assay. The effect of isopropanol, povidone-iodine, sodium hypochlorite, chlorhexidine digluconate, benzalkonium chloride, ethanol and triclosan on biofilms was determined. The effect of povidone-iodine on biofilm biomass and thickness was also determined by Confocal Laser Scanning Microscopy (CLSM).
ResultsmrkA expression ranged 28.2-1.3 (high or intermediate-level; 64% of HR clones) and 21.5-1.3 (50% of non-HR clones). At 25°C biofilm formation was observed in 41% of isolates (absence of humidity) and 35% of isolates (presence of humidity), whereas at 37°C it was observed in 76% of isolates, with and without humidity. At 25°C biofilm producers were more frequently observed in HR clones (45% with humidity and 55% without humidity) than non-HR clones (17% with and without humidity). Biofilm viability from day 21 was higher at 25°C than 37°C. The greatest decrease in biofilm formation was observed with povidone iodine (29% decrease), which also decrease biofilm thickness.
ConclusionsBiofilm formation in carbapenemase-producing K. pneumoniae is related to mrkA expression. Biofilm formation is affected by temperature (37°C>25°C) whereas humidity has little effect. Biofilm viability is affected by temperature (25°C>37°C). At 25°C, HR clones are more frequently biofilm producers than non-HR clones. Povidone-iodine can decrease biofilm production and biofilm thickness.
KeywordsKlebsiella pneumoniae
carbapenemase
biofilm
biocide
mrkA
AbbreviationsCLSMconfocal laser scanning microscopy
CP-Kpcarbapenemase-producing K. pneumonia
NGSnext-generation sequencing
PECplasmid-encoded carbapenemases
WGSWhole genome sequencing
View full text© 2022 Elsevier Ltd and International Society of Antimicrobial Chemotherapy. All rights reserved.
留言 (0)