Characterization of Antibiotic Resistant Biofilm Producing Bacteria from Pharmaceutical Wastewater

Abstract

The study aimed to isolate biofilm producing bacterial strains from pharmaceutical waste water and determine their antibiotic resistance profile. Pharmaceutical waste water samples were collected and bacterial strains were isolated and characterized by biochemical tests. Antibiotic resistance profile was obtained against commonly used antibiotics. The bacterial strains were evaluated for their biofilm formation by quantitative assay using 96-well flat bottom microtiter plate. The strains were confirmed by Polymerase Chain Reaction (PCR) using 16S rRNA universal primers. Among 24 isolated bacterial strains, 6 (28.5%) isolates were identified as E. coli, 9 isolates (37.5%) were identified as S. aureus, and 9 isolates (37.5%) were identified as Pseudomonas aeruginosa. All bacterial isolates showed high resistance (100%) to antibiotics including Cloxacilin, Ticarcilin, Ceftazidime, and Cefaclor but comparatively low resistance (66.66%) on average to Amoxicillin, Kanamycin, and Moxifloxacin. Among six E. coli isolates, 3 were weak biofilm formers, while 8 isolates of S. aureus were weak and 1 was moderate biofilm former. 4 isolates of P. aeruginosa exhibited weak biofilm formation. Three bacterial isolates of each genus having multi-drug resistance and biofilm forming ability were selected and sequenced. The sequences were submitted to NCBI Database and accession numbers were obtained for all the isolates. The prevalence of antibiotic resistance was recorded as being higher in biofilm producing strains in our study, which indicates possible correlation between increased biofilm forming potential and multi-drug resistance.