Abstract

Lactobacillus Acidophilus la-5 Inhibits Growth and Biofilm Formation of Methicillin Resistant Staphylococcus aureus Isolated from Wounds of Hospitalized Patients

Author(s): Salahuddin Khan and Salma Mahmud

The aim of the present study was to assess the ability of predominantly used probiotic strain Lactobacillus acidophilus La-5 to inhibit the growth and biofilm formation by Methicillin Resistant clinical isolates of S. aureus. A total of 41 clinical isolates of S. aureus were collected from wound samples of patients. Biofilm formation assay was performed using microtiter plate. At 24h incubation, 13 (31.70%, P<0.5) of the clinical isolates were strongly adherent, 25 (60.97%, P<0.5) were moderately adherent and only 3 (7.31%, P<0.5) were weakly adherent. Agar overlay interference test was employed to study the ability of L. acidophilus La-5 to inhibit the growth of S. aureus. The growth was completely inhibited at higher cell concentrations of L. acidophilus (107- 109). The inhibitory effects declined with lowering of cell concentration. The assay to study the inhibition of biofilm formation was conducted using microtiter plate and staining with crystal violet. Only 5 of the 13 strong biofilm producers were able to form biofilm upon introduction of probiotic strain. There were only 6 out of 25 moderate biofilm producers and none of the three weak biofilm formers were able to form biofilm upon co-inoculation with L. acidophilus La-5.