A Phenotypic and Molecular Study of Biofilm Production in Pseudomonas aeruginosa Isolated from Some Selected Hospital Wastewater Samples in Baghdad, Iraq

Hospital wastewater represents a unique type of waste that is extremely harmful to public health as it contains a wide variety of microbial species and related genomes. This work aimed to characterize the production of biofilm in hospital wastewater isolates of Pseudomonas aeruginosa at the genotypic and phenotypic levels. The strains were identified with cultural and biochemical characteristics, microscopic patterns, and the Vitek 2 Compact System. The isolates were assessed for biofilm formation through the measurement of the adhesion of cells to the microtiter plates. The existence of quorum sensing (QS) genes was determined using Polymerase Chain Reaction (PCR) in isolates including lasI, lasR, rhlR, rhlAB, lasB and aprA. The present findings indicated that of the 70 P. aeruginosa isolates, 78.57% (55/70) were biofilm producers: 27 (47.27%) were classified as weak biofilm producers, and the rates of moderate and strong biofilm producers were 19 (34.54%) and 11 (20%), respectively. Furthermore. All examined isolates positively produced the QS genes. According to the findings, biofilm served as a survival mechanism for bacteria in hospital wastewater, providing bacteria with more favorable habitats than planktonic forms. It also implied the significance of QS in the production and persistence of P. aeruginosa biofilms by allowing the density of populations to be recognized. Therefore, the detection of these genes and their correlation with the production of biofilm may be useful in restricting the spread of pathogenic bacteria in wastewater.