Abstract
Background: Biofilm is a surface adhered extracellular polymer matrix produced by bacteria. The establishment of biofilms is considered as an important pathogenic trait in many chronic infections and antibiotic resistance. Objective: The present study was intended to evaluate biofilm forming potency and antibiotic resistance (AR) pattern in clinical and non-clinical bacterial isolates, and their phylogenetic characterization. Materials and Methods: A total of 82 bacterial isolates were obtained from clinical settings and animal farms from southern (Kushtia-Jhenaidah) region of Bangladesh. Biofilm forming potentials and AR profile were evaluated by standard biofilm assay and Kirby-Bauer disk diffusion method, respectively. Further, antibiotic exposure was assessed by multiple antibiotic resistance (MAR) value indexing. Furthermore, statistical methods were applied to estimate the relationship between AR and biofilm formation. Finally, selected isolates were characterized by morphological and biochemical tests, as well as 16S rRNA gene sequencing. Results: Clinical isolates showed higher biofilm formation (OD595=1.17±0.03) than non-clinical isolates (OD595=0.68±0.03). Among all, Pseudomonas isolates produced the highest amount of biofilms (OD595=2.08±0.02). The AR profiles fell within 46.67-86.67% and MAR index ranged from 0.47 to 0.87. Moreover, a significant positive correlation (P<0.05) was found between biofilm formation and AR. Eventually, heavy biofilm producers with ≥60% resistance profile were characterized and identified as Escherichia coli, Cronobacter sakazakii, Pseudomonas aeruginosa, Staphylococcus sciuri, and Staphylococcus aureus. Conclusion: In general, biofilm formation and MAR were highly correlated regardless of the source, type, and environment of the isolates. Therefore, a rigorous evaluation of both biofilm formation and AR is demanded to minimize AR and associated problems.
Highlights
Biofilm is a surface adhered extracellular polymer matrix produced by bacteria
The present study aimed to assess the biofilm forming potency, antibiotic resistance (AR) profile, and molecular phylogeny of bacterial isolates obtained from clinical settings (i.e., Kushtia General Hospital and Islamic University Medical Center) and animal farms in nearby cities, Kushtia, and Jhenaidah, Bangladesh
Biofilm Formation and Selection of Heavy Biofilm Producers As shown in Figures 1a-c, the qualitative and quantitative evaluation suggest that all the isolates produced biofilms at a different extent
Summary
Biofilm is a surface adhered extracellular polymer matrix produced by bacteria. The establishment of biofilms is considered as an important pathogenic trait in many chronic infections and antibiotic resistance. The formation of biofilm, as a surface-attached sessile microbial community is viewed as one of their key survival strategies.[1] In addition, it is well-known to play a significant role in chronic infection and antibiotic resistance (AR).[2] For example, dental plaque is a common biofilm-mediated problem which contains more than 700 bacterial species.[3] resistant to antibiotics is more prevalent in bacteria within biofilm compared to their free-living counterparts due to the inaccessible extracellular polymer matrix present in the biofilm structure.[2,4] Further, the growing AR is attributed to the overuse and misuse of antibiotics in clinical setting and feedstocks preparation for therapeutic reasons and growth promotion, respectively.[5,6] AR complicates and can jeopardize the treatment of serious bacterial infections in both animals and humans.[7]
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