Association of CRISPR/Cas system with integrons and antibiotic resistance in Kliebsiella pneumoniae.

AIMS: The interaction between the CRISPR/Cas system and drug resistance was investigated in this study.

METHODS

In this study, 24 isolates, identified as Klebsiella pneumoniae, were subjected to antimicrobial sensitivity screening and detecting the presence of cas, integrons, and antibiotic resistance genes.

RESULTS

The highest resistance level could be detected in ceftriaxone and amoxicillin by 79% and 70.8%, respectively, while the lowest was 16.7% for chloramphenicol. Additionally, 50% of all isolates exhibited multidrug resistance (MDR); however, extensive drug resistance (XDR) was present in 12.5%. Class 1 integrons with different sizes could be identified. sul1 and sul2 were the most resistance genes identified, followed by aacA4 and aac(3)-II and qnrS, with 58%, 50%, 41.7%, 33%, and 33%, respectively. Concerning CRISPR genes, cas3 could be identified in nine different isolates; however, cas1 could be detected in 11 different isolated strains. In case of CRISPR1, it was found in seven isolates (29.3%), while CRISPR2 could be identified in three different isolates (12.5%).

CONCLUSIONS

Antibiotic resistance genes were mostly correlated with CRISPR genes. Interestingly, BOX-PCR group A, with a lower number of CRISPR positive isolates (p = 0.046) had a limited number of detected genes, compared with other groups indicating a significant correlation between antibiotic resistance genes and cas genes (p = 0.0023).