CRISPR-Cas May Prevent Acquisition of Drug Resistance in Klebsiella pneumoniae

Abstract Background Klebsiella pneumoniae (Kp) is a Gram-negative bacterium that causes nosocomial UTIs, pneumonia, and sepsis. Carbapenem-resistant Kp (CR-Kp) is associated with hospital outbreaks, is difficult to treat, and has high mortality rates prompting study of how resistance is obtained. In...

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Veröffentlicht in:Open forum infectious diseases 2017-10, Vol.4 (suppl_1), p.S230-S230
Hauptverfasser: Mackow, Natalie, Diago-Navarro, Elizabeth, Fries, Bettina
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Sprache:eng
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Zusammenfassung:Abstract Background Klebsiella pneumoniae (Kp) is a Gram-negative bacterium that causes nosocomial UTIs, pneumonia, and sepsis. Carbapenem-resistant Kp (CR-Kp) is associated with hospital outbreaks, is difficult to treat, and has high mortality rates prompting study of how resistance is obtained. In U.S. strains, resistance to Carbapenems is primarily conferred by genes blaKPC-2 and blaKPC-3. Transmission of these genes is via plasmids and to investigate their acquisition, this project analyzed the function of CRISPR-Cas in Carbapenem sensitive Kp (CS-Kp) hospital strains. The CRISPR-Cas system has been found to suppress homologous gene transfer and prevent integration of new genes by plasmids or bacteriophages. This study’s hypothesis is that Kp strains that lack CRISPR-Cas can acquire CR plasmids, while those strains that have CRISPR-Casare protected from gaining these plasmids and can maintain sensitivity to Carbapenems. Methods Kp strains from the urine of patients from Montefiore Medical Center and Stony Brook University Hospital were collected and sensitivity to Carbapenems was determined by chart review. Next, hospital strains were screened for CRISPR-Cas using PCR. 4 CS-Kp strains (strains 1 and 2 without CRISPR-Cas, and strains 3 and 20 with CRISPR-Cas) were studied. blaKPC-2, blaKPC-3, and control plasmid pPROBEKT-GFP (KmR) were then transformed into Kpby standard electroporation. Meropenem agar plates for CR-containing plasmids, Kanamycin for control plasmids, and PCR were used to evaluate transformation success. Results Successful transformation of blaKPC-2, blaKPC-3, and the control plasmid was achieved in strains 1 and 2, which lacked CRISPR-Cas. Successful transformation of the control plasmid was achieved in strains 3 and 20. However, neither blaKPC plasmid could be transformed into strain 3, and while very low success was seen with blaKPC-3 in strain 20, blaKPC-2could not be transformed into that strain either. Conclusion This study supports the hypothesis that CRISPR-Cas prevents acquisition of drug resistance plasmids. It is notable that a CS-Kp strain with CRISPR-Cas was protected against one KPC gene and not fully against the other. This may indicate a difference in the CRISPR sequences in individual Klebsiella strains. Disclosures All authors: No reported disclosures.
ISSN:2328-8957
2328-8957
DOI:10.1093/ofid/ofx163.481