CRISPR-Cas system in Pseudomonas aeruginosa and its association to antibiotic resistance and phage susceptibility

Aim ; The study was conducted to establish the association between CRISPR-Cas system in Pseudomonas aeruginosa clinical and environmental strains to the sensitivity to phages and antibiotics. Method; In this study, the occurrence and distribution of CRISPR-Cas system was analyzed across the 50 Pseudomonas aeruginosa strains. Further, to evaluate the role of CRISPR-Cas system as inhibitor of HGT, the role of CRISPR-Cas system in relation to susceptibility of Pseudomonas aeruginosa to various antibiotics and phages was studied. Result : A total of 5 different types of Type I CRISPR- Cas systems i.e. Type IF, Type IE, Type IC, Type IV and Type IU were identified in P. aeruginosa strains. A total of 5 (17%) clinical strains and 8 (40%) environmental strains were positive for both CRISPR and cas3 gene. The analysis of phage as well as antibiotic susceptibility of both clinical and environmental strains revealed 36% clinical strains and75% environmental strains were found to be resistant to phages. Antibiotic susceptibility results were in contrast to phage susceptibility as 50% clinical strains were resistant to at least 3 antibiotics i.e. they were multidrug resistant (MDR) while only 15% environmental strains were classified as MDR. Conclusion : The phage susceptibility and antibiotic resistance data was found to be correlating to presence of CRISPR-Ca system in the P. aeruginosa .