Anti-biofilm potential of Lactobacillus plantarum Y3 culture and its cell-free supernatant against multidrug-resistant uropathogen Escherichia coli U12

Abstract

Uropathogens develop biofilms on urinary catheters, resulting in persistent and chronic infections that are associated with resistance to antimicrobial therapy. Therefore, the current study was performed to control biofilm-associated urinary tract infections through assaying the anti-biofilm ability of lactic acid bacteria (LAB) against multidrug-resistant (MDR) uropathogens. Twenty LAB were obtained from pickles and fermented dairy products, and screened for their anti-biofilm and antimicrobial effects against MDR Escherichia coli U12 (ECU12). Lactobacillus plantarum Y3 (LPY3) (MT498405), showed the highest inhibitory effect and biofilm production. Pre-coating of a microtitre plate with LPY3 culture was more potent than co-incubation. Pre-coating with LPY3 culture generated a higher anti-biofilm effect with an adherence of 14.5% than cell free supernatant (CFS) (31.2%). Anti-biofilm effect of CFS was heat stable up to 100 °C with higher effect at pH 4-6. Pre-coating urinary catheter with LPY3 culture reduced the CFU/cm² of ECU12 attached to the catheter for up to seven days. Meanwhile, CFS reduced the ECU12 CFU/cm² for up to four days. Scanning electron microscope confirmed the reduction of ECU12 adherence to catheters after treatment with CFS. Therefore, Lactobacillus plantarum can be applied in medical devices as prophylactic agent and as a natural biointervention to treat urinary tract infections.

Keywords: Adherence; BHI, brain heart infusion; Biofilms; CAUTI, catheter associated urinary tract infection; CFU, colony forming unit; CRA, congo red agar; CV, crystal violet; LAB, Lactic acid bacteria; LPY3, Lactobacillus plantarum Y3; Lactic acid bacteria; MRS, De Man, Rogosa, and Sharpe; PBS, phosphate-buffered saline; SEM, scanning electron microscope.

Fig. 1

Phylogenetic tree of L. plantarum Y3 (a), and E. coli U12 (b).

Fig. 2

Effect of pre-coating and co-incubation with LPY3 culture and its CFS on biofilm formation of ECU12. Statistical analysis was performed by One- way ANOVA and L.S.D. Means with different letters within column are significant difference, P ≤ 0.05–0.01. Means with the same letters within column are non significant difference.

Fig. 3

Effect of different temperatures on anti-biofilm effect of CFS of LPY3 against ECU12. Statistical analysis was performed by One- way ANOVA and L.S.D. Values represent the mean of three replicates. Error bars are the standard deviation of the mean. Means with different letters within column are significant difference, P ≤ 0.05–0.01. Means with the same letters within column are non significant difference.

Fig. 4

Effect of different pH values on the anti-biofilm effect of CFS of LPY3 against ECU12. Statistical analysis was performed by One- way ANOVA and L.S.D. Values represent the mean of three replicates. Error bars are the standard deviation of the mean. Means with different letters within column are significant difference, P ≤ 0.05–0.01. Means with the same letters within column are non significant difference.

Fig. 5

Inhibition of biofilm formation of E. coli U12 on urinary catheter. Statistical analysis was performed by One- way ANOVA and L.S.D. T-Test : ** significant difference at p < 0.05–0.01 Values are the mean of three replicates ± standard deviation. Means with different letters within column are significant difference, P ≤ 0.05–0.01.

Fig. 6

Electron micrographs of ECU12 adhered on urinary catheter pieces after treatment with CFS of LPY3, a: positive control, b: first day, c: third day, d: sixth day.