In vitro effect of subinhibitory concentrations of antibiotics on biofilm formation by clinical strains of Salmonella enterica serovar Typhimurium isolated in Slovakia

Abstract

Aims: In this study, we examined the biofilm formation of 75 Salmonella enterica serovar Typhimurium (Salm. Typhimurium) human clinical isolates and the effect of subinhibitory concentrations (sub‐MICs) of gentamicin, ciprofloxacin and cefotaxime on biofilm formation and exopolysaccharides (EPS) production. Methods and Results: Quantification of biofilm formation and EPS production were carried out using a modified microtitre plate assay and spectrophotometric method, respectively. The results indicate that 38 isolates (50·7%), which are predominantly of DT104 phage type, presented as the strong biofilm producers in vitro on plastic surface. When strains with the highest biofilm‐forming capacity were grown in the presence of sub‐MICs of gentamicin and ciprofloxacin, the inhibition of biofilm formation and EPS production was observed. In contrast, cefotaxime at 1/2 MIC (0·039 μg ml−1) was able to significantly induce the production of biofilm as well as EPS in three isolates with nontypable and DT104 phage type, respectively. Conclusions: These results clearly indicate that all the three antibiotics tested are able to interfere with biofilm formation and EPS production by Salm. Typhimurium isolates. Significance and Impact of the Study: The current study demonstrated that cefotaxime at sub‐MIC can be beneficial for the behaviour of pathogen Salm. Typhimurium in vitro.

Environmental phosphate differentially affects virulence phenotypes of uropathogenicEscherichia coliisolates causative of prostatitis

“…Similar result were previously observed in Staphylococcus epidermidis isolates using macrolides 54 and in Salmonella enteric serovar Typhimurium in which biofilm and EPS production was improved after treatment with sub-inhibitory concentrations of cefotaxime. 55 It is worth to note that, when antibiotic was added at 24 h, the above mentioned induction of biofilm formation was not observed in the BF-conditions (not shown).…”

Antibiotic Resistance Pattern and Biofilm Formation Ability of Clinically Isolates of Salmonella enterica Serotype typhimurium

“…Different studies were conducted to compare the ability of different Salmonella serovars to produce biofilm on different surface (21,22). Various factors (growth medium, incubation period, fixation of adhered cells and staining) affect development of Salmonella biofilm on microtiter plate (23).…”

Comparative Proteomic Analysis of Streptococcus suis Biofi lms and Planktonic Cells That Identifi ed Biofi lm Infection-Related Immunogenic Proteins

“…CIP is known for being initially very effective against P. aeruginosa. GM is also used to control P. aeruginosa growth and has been described in several works as a potential antibiotic to treat bio�lm associated infections [32][33][34]. However, the diminished bio�lm-forming capacity shown by PA and PAI under CIP and GM pressure may be related with other actions than bactericidal activity.…”