Antimicrobial effect of probiotic Lactobacillus spp. on Pseudomonas aeruginosa

Abstract

Objectives Study the antimicrobial effect of probiotics produced from Lactobacillus rhamnosus GG and Lactobacillus acidophilus on Pseudomonas aeruginosa isolated from burn and wound infection and their ability of protease production.
Methods Swab samples were collected from 70 patients admitted at Burns Center/Al-Yarmouk Teaching Hospital. Primary bacterial identification cultured on differential selective media and biochemical tests were done. The Vitek2 compact system (Biomerieux, France) was used to confirm the P. aeruginosa isolates by Gram negative identification card and the antimicrobial susceptibility Test Card to each isolate was performed. Protease production using skimmed milk agar 1% was performed. Crud bacteriocin produced from L. acidophilus (Holland & Barrett, USA) and L. rhamnosus (Health Gensis, USA) was extracted during log phase using MRS broth (24 h/ 37ºC/ 5–10% CO2), then cool centrifugation was done (6000 rpm at 4ºC for 10 min). Protein concentration of bacteriocin was estimated using Bradford assay using bovine serum albumin as standard.
Results Only 31 out of 48 isolates were identified as P. aeruginosa; 9 (45%) from wound and 22 (79%) from burn swabs. Antimicrobial susceptibility tests included 16 antibiotics; P. aeruginosa isolates showed multi-drug resistance for antibiotics. All P. aeruginosa isolates were having the ability for protease enzyme production. Antimicrobial effect of bacteriocin produced by L. acidophilus and L. rhamnosus on protease using plate diffusion method showed positive results. Protein concentration of bacteriocin produced by L. rhamnosus and L. acidophilus were 74 mg/mL, 44 mg/mL, respectively. The highest zone of antimicrobial effect by L. rhamnosus was 32 mm and by L. acidophilus was 25 mm using well diffusion method.
Conclusions P. aeruginosa showed a multi-drug resistance and had the ability to produce protease enzyme. Bacteriocin produced by L. acidophilus and L. rhamnosus showed an acceptable positive results to be used as potential alternative bio-remedy to overcome the multi-drug resistance dilemma.
Keywords antimicrobial effect, Lactobacillus spp., bacteriocin, Pseudomonas aeruginosa, protease