In vitro activities of cellulase and ceftazidime, alone and incombination against Pseudomonas aeruginosa biofilms

Background and Aim : Biofilms are a main pathogenicity feature of Pseudomonas aeruginosaand has a significant role in antibiotic resistance and persistent infections in humans. Weinvestigated the in vitro activities of antibiotic ceftazidime and enzyme cellulase, either alone orin combination against biofilms of P. aeruginosa.Methods : P. aeruginosa PAO۱ and two clinical isolates of P. aeruginosa recovered from thepatients with burn wound were used in this study. The MIC (minimum inhibitory concentration)and MBC (minimum bactericidal concentration) of ceftazidime was determined. The bactericidalactivity of cellulase on planktonic cells of P. aeruginosa was evaluated. Biofilm formation wasassessed by the colorimetric microtiter plate assay. Moreover, the activities of cellulase andceftazidime, alone and in combination, on biofilm attachment, biofilm formation, and minimumbiofilm elimination concentration (MBEC) were evaluated.Results : Both ceftazidime and cellulase significantly decreased biofilm formation in all strains ina dose-dependent manner. Combination of enzyme at concentrations of ۱.۲۵, ۲.۵, ۵, and ۱۰ U/mLtested with ۱/۱۶× MIC of antibiotic led to a significant reduction in biofilm biomass. Cellulaseshowed a significant detachment effect on biofilms at three concentrations of ۱۰ U/mL, ۵ U/mL,and ۲.۵ U/mL. The MIC, MBC, and MBEC values of ceftazidime were ۲ to ۴ μg/mL, ۴ to ۸ μg/mL,and ۲۰۴۸ to ۸۱۹۲ μg/mL. When combined with cellulase, the MBECs of antibiotic showed asignificant decrease from ۳۲- to ۱۲۸-fold.Conclusion : Combination of the ceftazidime and the cellulase had significant anti-biofilm effects,including inhibition of biofilm formation and biofilm eradication in P. aeruginosa. These datasuggest that glycoside hydrolase therapy as a novel strategy has the potential to enhance theefficacy of antibiotics and helps to resolve biofilm-associated wound infections caused by thispathogen.

کلیدواژه ها:

Biofilm inhibition ، Ceftazidime ، Cellulase ، MBEC ، Pseudomonas aeruginosa