Molecular and bacteriological investigations for the co-existence CRISPR/Cas system and β-lactamases of types extended-spectrum and carbapenemases in Multidrug, extensive drug and Pandrug-Resistant Klebsiella pneumoniae.

The recent approach towards combating the antimicrobial resistance has led to the use of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and associated sequence to overcome the challenges of antimicrobial resistance. Thus, this study aimed to detect the underlying resistance mechanisms such as ESBLs and carbapenemases and whether there is a correlation between multidrug, extensive drug and pan drug resistance and the occurrence of CRISPR loci. A total of one hundred study isolates were subjected to antimicrobial susceptibility testing using the AST card of the Vitek technique to detect resistance patterns involving ESBLs and carbapenemase (CRE). An investigation of the genes encoding CRISPR/Cas systems using PCR was achieved. Out of 81 (81.0%) resistant Klebsiella pneumoniae isolates, 71 (71%) and 21 (21.0%) produced ESBLs and carbapenemases, respectively. Also, 53 (53.0%), 19 (19.0%) and 9 (9.0%) were MDR, XDR, and PDR respectively. It was noted that Cas1, Cas3, CRISPR1, CRISPR2 and CRISPR3 were positive in 38 (38.0%) of the isolates, while CRISPR1 for incomplete CRISPR1-Cas systems alone was detected in 78 (78.0%). Further, the number of intact CRISPR1, intact CRISPR2 and intact CRISPR3 types were 7 (27.0%), 34 (34%) and 18 (18.0%) respectively. It is concluded that antibiotic resistance levels were inversely correlated with the existence of CRISPR/Cas systems. The absence of the CRISPR/Cas system increases the prevalence of MDR, XDR and PDR in ESBL and carbapenem-producing Klebsiella pneumoniae. With the increase in the degree of antibiotic resistance (MDR, XDR to PDR), the occurrence ratio of the (CRISPR)/CRISPR-associated sequence decreased.