Association between gentamicin resistance and stress tolerance in water isolates of Ralstonia pickettii and R. mannitolilytica

Abstract

Members of the species Ralstonia pickettii and R. mannitolilytica, although ubiquitous and lacking major virulence factors, have been associated with nosocomial outbreaks. Tolerance to metals, antibiotics, and disinfectants may represent an advantage for their ubiquity and opportunistic pathogenic potential. In this study, we compared five strains that differed on the origin (hospital effluent, tap water, mineral water) and in the susceptibility to aminoglycosides, regarding their tolerance to metals and disinfection. The growth kinetics and biofilm formation capacity were tested in four R. pickettii strains and one R. mannitolilytica at sub-inhibitory concentrations of aminoglycosides or arsenite. The survival to UV radiation, chlorine, or hydrogen peroxide was also compared in aminoglycoside resistant and susceptible strains. Aminoglycoside-resistant strains presented a higher tolerance to arsenite than the susceptible ones and either aminoglycosides or arsenite was observed to stimulate the biofilm formation. Sub-inhibitory concentrations of the aminoglycoside gentamicin or arsenite significantly decreased the growth rate and yield, but only arsenite caused a significant increase of the lag phase. Hydrogen peroxide presented higher disinfection effectiveness against aminoglycoside susceptible than against resistant strains, an effect that was not observed for UV or chlorine. Although this conclusion needs validation based on a larger number of isolates, including clinical, the results suggest that aminoglycoside resistance may be associated with traits that influence Ralstonia spp. fitness in the environment.

Monitoring and controlling bacteria in pharmaceutical industries water system

“…All micro-organisms except R. pickettii were sensitive to gentamicin that was in agreement with Ferro et al (2019) who stated the resistance of R. pickettiia against gentamicin could be due to a multidrug efflux pump found in the genomes.…”

Betaproteobacteria are predominant in drinking water: are there reasons for concern?

“…Associated with the capacity to survive treatment processes (e.g. disinfectants, toxic metals, antibiotics), the capacity of Betaproteobacteria to form biofilms is frequently described (Mah and O'Toole 2001;Emtiazi et al 2004;Schwering et al 2013;Ertekin et al 2016;Flemming et al 2016;Ferro et al 2019). The association between both characteristics may have two explanations: i) the bacteria with increased fitness to survive antimicrobial agents are those able to form or incorporate biofilm structures, or ii) the biofilm provides an increased protection against external attacks (e.g.…”

Antimicrobial Treatment on a Catheter-Related Bloodstream Infection (CRBSI) Case Due to Transition of a Multi-Drug-Resistant Ralstonia mannitolilytica from Commensal to Pathogen during Hospitalization

“…In addition, from an extensive surveillance during 2014 (including the duration of hospitalization), the R. mannitolilytica strain was rarely identified as an infectious agent for other patients, nor was it routinely isolated from drinking water, laboratory-based water, saline solutions used for patient care or catheters [ 25 , 26 , 27 ].…”