The effect of cationic microbicide exposure againstBurkholderia cepaciacomplex (Bcc); the use ofBurkholderia latastrain 383 as a model bacterium

Abstract

Aim: The extensive use of microbicides in a wide range of applications has been questioned with regard to their role in the development of bacterial resistance to antimicrobials. This study aims to measure the phenotypic and genotypic changes in Burkholderia lata strain 383 exposed to chlorhexidine gluconate (CHG) and benzalkonium chloride (BZC), two commonly used cationic microbicides. Methods and Results: The susceptibility of B. lata strain 383 to CHG and BZC and a range of antibiotics was determined using standardized MIC, MBC and antibiotic susceptibility testing protocols before and after short-term exposure to a low microbicide concentration. Measurements were performed on four separate occasions over a 1-year period. Changes in gene expression were investigated using quantitative real-time PCR. Although the susceptibility profile to CHG and BZC was not altered, a change in antibiotic susceptibility profile was observed for ceftazidime, and for imipenem and ciprofloxacin in 2/4 repeats. An outer membrane protein and ABC transporter were found to be significantly upregulated following treatment with BZC and CHG, respectively. Conclusions: The comparison of MIC and MBC results following microbicide exposure with baseline data offered a prospective protocol to quantify any change in bacterial susceptibility profile. However, the use of a standardized antibiotic susceptibility protocol with B. lata strain 383 showed some inconsistencies in results between repeats. Significance and Impact of the Study: With ever-increasing interest in the impact of microbicides on emerging antimicrobial resistance in bacteria growing, this study demonstrated that comparing susceptibility profile obtained after exposure to microbicides with baseline susceptibility values could play a role in establishing the potential risk of microbicide resistance and cross-resistance development and also in the development of a protocol that allows the prediction of microbicide resistance.

The effects of pharmaceutical and personal care products on the behavior of Burkholderia cepacia isolated from drinking water

“…The remaining wells were filled with 200 μl of STW and used as negative disinfection control. After the incubation period, a neutralization step (Knapp et al, 2013) was performed using sodium thiosulfate at a final concentration of 5% (w/v). Following this, the biofilm from each well was resuspended in 200 μl of saline water (0.85%) and reserved in a microcentrifuge tube.…”

Development of a Protocol for Predicting Bacterial Resistance to Microbicides

“…The stability of any alterations in antimicrobial susceptibility observed after 5 min of exposure of S. enterica strains SL1344 and 14028S to a range of low CHG and BZC concentrations was investigated via the 24-h subculture of surviving organisms through TSB with or without a low concentration of CHG or BZC, as described previously (4).…”

“…The neutralizer used was composed of Tween 80 (30 g/liter) and asolectin (3 g/liter) (both from Sigma-Aldrich, Dorset, United Kingdom). The efficacy of the neutralizer to quench the antimicrobial activities of the mouthwash, shampoo, and eye makeup remover and the toxicity of the neutralizer toward all bacterial strains tested were determined as described previously (4). Antimicrobial susceptibility testing.…”

“…Resistance or reduced susceptibility to microbicides and/or antibiotics as a result of exposure to low microbicide concentrations has been demonstrated extensively in the laboratory setting (4)(5)(6)(7)(8). Despite the lack of in vivo or in situ studies reporting a link between microbicide exposure and antibiotic resistance development, in vitro studies have clearly demonstrated the possibility of microbicide and antibiotic resistance development in bacteria.…”

Factors affecting removal of bacterial pathogens from healthcare surfaces during dynamic wiping

“…The neutraliser was manufactured according to the methodology outlined by Ramm et al (12). The toxicity of the neutraliser and its ability to quench the activity of the biocide was tested according to the method outlined by Knapp et al (2013) (23).…”