The Relation Between Biofilm Formation and Alginate Production in <i>Pseudomonas aeruginosa</i>; An Important and Neglected Topic

Background and Aim: Pseudomonas aeruginosa (P.aeruginosa) is one of the most common opportunistic bacteria causing healthcare-associated infections (HAIs).Alginate as an adhesion substance plays role in its binding to inanimate surfaces and protecting against environmental conditions.Biofilm also increases the bacterial resistance to antimicrobials and immune system.The present study was aimed to survey the antimicrobial resistance pattern, biofilm formation, and alginate production in the clinical isolates of P. aeruginosa. Materials and Methods:In this cross-sectional study in a period of one year 90 non-duplicative P. aeruginosa were isolated from the clinical samples.Antimicrobial susceptibility testing was performed by disk diffusion method.Biofilm formation and alginate production were measured by microtiter plate and carbazole assay, respectively.Polymerase chain reaction was conducted for detection of pslA, pelA, ppyR, algD, algU and algL genes. Results:The highest resistance rate (74.4%) was related to ceftazidime.Alginate production was found in 87.8% of the isolates, which production levels were <250 gml -1 , 250-400 gml -1 , and >400 gml -1 in 7.6%, 53.2%, and 39.2 of the isolates, respectively.The categories of biofilm formation in strains were as weak (11.1%), moderate (24.1%), and strong (64.8%).The prevalence of ppyR, algD, algU, algL, pslA and pelA genes were 100.0%,92.2%, 86.6%, 67.7%, 85.2% and 42.5%, respectively. Conclusion:The results highlighted an alarming trend in P. aeruginosa strains antibiotic resistance rates.A significant relationship was also observed between the alginate production and the biofilm formation.Thus, periodic monitoring, adherence to the antibiotic stewardship, avoiding arbitrary prescribing, and screening tests are unavoidable.