A comparative analysis of CRISPR systems, virulence factors, and antibiotic resistance genes in carbapenem-sensitive and carbapenem-resistant Klebsiella pneumoniae
Abstract
Background and Objectives: Klebsiella pneumoniae is a major cause of healthcare-associated infections, particularly in immunocompromised patients. This study compares the CRISPR systems, virulence factors, and antibiotic resistance genes in carbapenem-sensitive (CSKP) and carbapenem-resistant (CRKP) clinical isolates.
Materials and Methods: Carbapenemase-producing isolates were identified by mCIM/eCIM. PCR and RT-qPCR detected key genes, including cas3, involved in CRISPR-Cas function. In silico analyses included STRING for protein interactions, CRISPRCasdb for CRISPR subtype distribution, and Phyre2/AlphaFold for cas3 structure prediction.
Results: Among the isolates, 35.2% were resistant to carbapenems. Among CRKP strains, high prevalence of bla-NDM-1 (82%) and bla-OXA-48 (64%) was observed. The cas3 expression was significantly upregulated in resistant isolates (P = 0.002). CRISPR subtype I-E was identified in 16% of CRKP and 36% of CSKP isolates. Structural-functional analysis supported the integrity of Cas3 and revealed interactions with regulatory and iron acquisition proteins. Statistically significant differences in virulence and resistance gene profiles were found between CRKP and CSKP groups (P < 0.05).
Conclusion: This study highlights key differences between CRKP and CSKP isolates, particularly in CRISPR-Cas systems, resistance, and virulence. The findings suggest that cas3 plays a critical role in genomic adaptation and resistance mechanisms in K. pneumoniae, offering insights for future therapeutic strategies.
1. Lin X-c, Li C-l, Zhang S-y, Yang X-f, Jiang M. The global and regional prevalence of hospital-acquired carbapenem-resistant Klebsiella pneumoniae infection: a systematic review and meta-analysis. Open Forum Infect Dis 2023; 11(2): ofad649.
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3. Chen I-R, Lin S-N, Wu X-N, Chou S-H, Wang F-D, Lin Y-T. Clinical and microbiological characteristics of bacteremic pneumonia caused by Klebsiella pneumoniae. Front Cell Infect Microbiol 2022;12: 903682.
4. Nezhadi J, Ahangarzadeh Rezaee M, Asghari Ozma M, Ganbarov K, Samadi Kafil H. Gut microbiota exchange in domestic animals and rural-urban people axis. Curr Pharm Biotechnol 2024; 25: 825-837.
5. Chen Y-C, Tsai I-T, Lai C-H, Lin K-H, Hsu Y-C. Risk Factors and Outcomes of Community-Acquired Carbapenem-Resistant Klebsiella pneumoniae Infection in Elderly Patients. Antibiotics (Basel) 2024; 13: 282.
6. Wang Z, Qin R-R, Huang L, Sun L-Y. Risk factors for carbapenem-resistant Klebsiella pneumoniae infection and mortality of Klebsiella pneumoniae infection. Chin Med J (Engl) 2018; 131: 56-62.
7. Liao K, Chen Y, Wang M, Guo P, Yang Q, Ni Y, et al. Molecular characteristics of extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae causing intra-abdominal infections from 9 tertiary hospitals in China. Diagn Microbiol Infect Dis 2017; 87: 45-48.
8. Onishi R, Shigemura K, Osawa K, Yang Y-M, Maeda K, Tanimoto H, et al. Molecular characteristics and genetic analysis of the genes related to carbapenemase, efflux pump, and outer membrane proteins in carbapenem-resistant Klebsiella pneumoniae. Lett Appl Microbiol 2023; 76(2): ovac069.
9. Derakhshan S, Saedi S, Ahmadi A, Hedayati MA. Virulence genes, phylogenetic analysis, and antimicrobial resistance of Escherichia coli isolated from urinary tract infection in hospitalized patients and outpatients. J Appl Genet 2022; 63: 805-813.
10. Wei L, Wu L, Wen H, Feng Y, Zhu S, Liu Y, et al. Spread of carbapenem-resistant Klebsiella pneumoniae in an intensive care unit: a whole-genome sequence-based prospective observational study. Microbiol Spectr 2021; 9(1): e0005821.
11. Wyres KL, Holt KE. Klebsiella pneumoniae as a key trafficker of drug resistance genes from environmental to clinically important bacteria. Curr Opin Microbiol 2018; 45: 131-139.
12. Ahmadi M, Ranjbar R, Behzadi P, Mohammadian T. Virulence factors, antibiotic resistance patterns, and molecular types of clinical isolates of Klebsiella pneumoniae. Expert Rev Anti Infect Ther 2022; 20: 463-472.
13. Saha U, Gondi R, Patil A, Saroj SD. CRISPR in modulating antibiotic resistance of ESKAPE pathogens. Mol Biotechnol 2023; 65: 1-16.
14. Morshedzadeh F, Ghanei M, Lotfi M, Ghasemi M, Ahmadi M, Najari-Hanjani P, et al. An update on the application of CRISPR technology in clinical practice. Mol Biotechnol 2024; 66: 179-197.
15. Kadkhoda H, Gholizadeh P, Ghotaslou R, Nabizadeh E, Pirzadeh T, Rezaee MA, et al. Role of CRISPR-cas system on virulence traits and carbapenem resistance in clinical Klebsiella pneumoniae isolates. Microb Pathog 2025; 199: 107151.
16. Li H-Y, Kao C-Y, Lin W-H, Zheng P-X, Yan J-J, Wang M-C, et al. Characterization of CRISPR-Cas systems in clinical Klebsiella pneumoniae isolates uncovers its potential association with antibiotic susceptibility. Front Microbiol 2018; 9: 1595.
17. Kamruzzaman M, Iredell JR. CRISPR-Cas system in antibiotic resistance plasmids in Klebsiella pneumoniae. Front Microbiol 2020; 10: 2934.
18. Long J, Zhang J, Xi Y, Zhao J, Jin Y, Yang H, et al. Genomic insights into CRISPR-harboring plasmids in the Klebsiella genus: distribution, backbone structures, antibiotic resistance, and virulence determinant profiles. Antimicrob Agents Chemother 2023; 67(3): e0118922.
19. Kadkhoda H, Gholizadeh P, Kafil HS, Ghotaslou R, Pirzadeh T, Rezaee MA, et al. Role of CRISPR-Cas systems and anti-CRISPR proteins in bacterial antibiotic resistance. Heliyon 2024; 10. doi: 10.1016/j.heliyon.2024.e34692.
20. Shen J, Lv L, Wang X, Xiu Z, Chen G. Comparative analysis of CRISPR‐Cas systems in Klebsiella genomes. J Basic Microbiol 2017; 57: 325–336.
21. Zhou Y, Tang Y, Fu P, Tian D, Yu L, Huang Y, et al. The type IE CRISPR-Cas system influences the acquisition of bla KPC-IncF plasmid in Klebsiella pneumonia. Emerg Microbes Infect 2020; 9:1011-1022.
22. Tang Y, Fu P, Zhou Y, Xie Y, Jin J, Wang B, et al. Absence of the type IE CRISPR-Cas system in Klebsiella pneumoniae clo nal complex 258 is associated with dissemination of IncF epidemic resistance plasmids in this clonal complex. J Antimicrob Chemother 2020; 75: 890-895.
23. Makarova KS, Koonin EV. Annotation and classification of CRISPR-Cas systems. CRISPR: methods and protocols 2015; 1311: 47–75.
24. Kadkhoda H, Gholizadeh P, Ghotaslou R, Pirzadeh T, Ahangarzadeh Rezaee M, Nabizadeh E, et al. Prevalence of the CRISPR-cas system and its association with antibiotic resistance in clinical Klebsiella pneumoniae isolates. BMC Infect Dis 2024; 24: 554.
25. Yousefi L, Kadkhoda H, Shirmohammadi M, Moaddab SY, Ghotaslou R, Pirzadeh T, et al. CRISPR-like sequences association with antibiotic resistance and biofilm formation in Helicobacter pylori clinical isolates. Heliyon 2024; 10. doi: 10.1016/j.heliyon.2024.e26809.
26. Liao W, Liu Y, Chen C, Li J, Du F, Long D, et al. Distribution of CRISPR-Cas systems in clinical carbapenem-resistant Klebsiella pneumoniae strains in a Chinese tertiary hospital and its potential relationship with virulence. Microb Drug Resist 2020; 26: 630-636.
27. Al Bshabshe A, Al-Hakami A, Alshehri B, Al-Shahrani KA, Alshehri AA, Al Shahrani MB, et al. Rising Klebsiella pneumoniae infections and its expanding drug resistance in the intensive care unit of a tertiary Healthcare Hospital, Saudi Arabia. Cureus 2020; 12. doi: 10.7759/cureus.10060.
28. Alhazmi W, Al-Jabri A, Al-Zahrani I. The molecular characterization of nosocomial carbapenem-resistant Klebsiella pneumoniae co-Harboring bla NDM and bla OXA-48 in Jeddah. Microbiol Res 2022; 13: 753-764.
29. Oteo J, Hernández JM, Espasa M, Fleites A, Sáez D, Bautista V, et al. Emergence of OXA-48-producing Klebsiella pneumoniae and the novel carbapenemases OXA-244 and OXA-245 in Spain. J Antimicrob Chemother 2013; 68: 317-321.
30. Stewart A, Harris P, Henderson A, Paterson D. Treatment of infections by OXA-48-producing Enterobacteriaceae. Antimicrob Agents Chemother 2018; 62(11): e01195-18.
31. Tu MM, Carfrae LA, Rachwalski K, French S, Catacutan D, Gordzevich R, et al. Exploiting the fitness cost of metallo-β-lactamase expression can overcome antibiotic resistance in bacterial pathogens. Nat Microbiol 2025; 10: 53-65.
32. Li H, Xie Y, Chen F, Bai H, Xiu L, Zhou X, et al. Amplification-free CRISPR/Cas detection technology: challenges, strategies, and perspectives. Chem Soc Rev 2023; 52: 361-382.
33. Bhatia S, Yadav SK. CRISPR-Cas for genome editing: classification, mechanism, designing and applications. Int J Biol Macromol 2023; 238: 124054.
34. Pursey E, Dimitriu T, Paganelli FL, Westra ER, Van Houte S. CRISPR-Cas is associated with fewer antibiotic resistance genes in bacterial pathogens. Philos Trans R Soc Lond B Biol Sci 2022; 377: 20200464.
35. Dogan O, Vatansever C, Atac N, Albayrak O, Karahuseyinoglu S, Sahin OE, et al. Virulence determinants of colistin-resistant K. pneumoniae high-risk clones. Biology (Basel) 2021; 10: 436.
36. Lam MM, Wyres KL, Judd LM, Wick RR, Jenney A, Brisse S, et al. Tracking key virulence loci encoding aerobactin and salmochelin siderophore synthesis in Klebsiella pneumoniae. Genome Med 2018; 10: 77.
37. Nazir A, Zhao Y, Li M, Manzoor R, Tahir RA, Zhang X, et al. Structural genomics of repA, repB1-carrying IncFIB family pA1705-qnrS, P911021-tetA, and P1642-tetA, multidrug-resistant plasmids from Klebsiella pneumoniae. Infect Drug Resist 2020; 13: 1889-1903.
38. Ferreira R, Da Silva B, Rezende G, Nakamura-Silva R, Pitondo-Silva A, Campanini E, et al. High prevalence of multidrug-resistant Klebsiella pneumoniae harboring several virulence and β-lactamase encoding genes in a Brazilian intensive care unit. Front Microbiol 2018; 9: 3198.
39. Valkovicova L, Valkova D, Vavrova S, Alekhina O, Hoang VP, Jezna M, et al. The role of TerW protein in the tellurite resistance of uropathogenic Escherichia coli. Biologia 2011; 66: 565-573.
40. Suzuki K, Tanabe T, Moon Y-H, Funahashi T, Nakao H, Narimatsu S, et al. Identification and transcriptional organization of aerobactin transport and biosynthesis cluster genes of Vibrio hollisae. Res Microbiol 2006; 157: 730-740.
41. Lymboussaki A, Pignatti E, Montosi G, Garuti C, Haile DJ, Pietrangelo A. The role of the iron responsive element in the control of ferroportin1/IREG1/MTP1 gene expression. J Hepatol 2003; 39: 710-715.
42. Bolourchi N, Naz A, Sohrabi M, Badmasti F. Comparative in silico characterization of Klebsiella pneumoniae hypervirulent plasmids and their antimicrobial resistance genes. Ann Clin Microbiol Antimicrob 2022; 21: 23.
43. Lai Y-C, Peng H-L, Chang H-Y. RmpA2, an activator of capsule biosynthesis in Klebsiella pneumoniae CG43, regulates K2 cps gene expression at the transcriptional level. J Bacteriol 2003; 185: 788-800.
44. Zhu J, Wang T, Chen L, Du H. Virulence factors in hypervirulent Klebsiella pneumoniae. Front Microbiol 2021; 12: 642484.
2. Guedes M, Gathara D, López-Hernández I, Pérez-Crespo PMM, Pérez-Rodríguez MT, Sousa A, et al. Differences in clinical outcomes of bloodstream infections caused by Klebsiella aerogenes, Klebsiella pneumoniae and Enterobacter cloacae: a multicentre cohort study. Ann Clin Microbiol Antimicrob 2024; 23: 42.
3. Chen I-R, Lin S-N, Wu X-N, Chou S-H, Wang F-D, Lin Y-T. Clinical and microbiological characteristics of bacteremic pneumonia caused by Klebsiella pneumoniae. Front Cell Infect Microbiol 2022;12: 903682.
4. Nezhadi J, Ahangarzadeh Rezaee M, Asghari Ozma M, Ganbarov K, Samadi Kafil H. Gut microbiota exchange in domestic animals and rural-urban people axis. Curr Pharm Biotechnol 2024; 25: 825-837.
5. Chen Y-C, Tsai I-T, Lai C-H, Lin K-H, Hsu Y-C. Risk Factors and Outcomes of Community-Acquired Carbapenem-Resistant Klebsiella pneumoniae Infection in Elderly Patients. Antibiotics (Basel) 2024; 13: 282.
6. Wang Z, Qin R-R, Huang L, Sun L-Y. Risk factors for carbapenem-resistant Klebsiella pneumoniae infection and mortality of Klebsiella pneumoniae infection. Chin Med J (Engl) 2018; 131: 56-62.
7. Liao K, Chen Y, Wang M, Guo P, Yang Q, Ni Y, et al. Molecular characteristics of extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae causing intra-abdominal infections from 9 tertiary hospitals in China. Diagn Microbiol Infect Dis 2017; 87: 45-48.
8. Onishi R, Shigemura K, Osawa K, Yang Y-M, Maeda K, Tanimoto H, et al. Molecular characteristics and genetic analysis of the genes related to carbapenemase, efflux pump, and outer membrane proteins in carbapenem-resistant Klebsiella pneumoniae. Lett Appl Microbiol 2023; 76(2): ovac069.
9. Derakhshan S, Saedi S, Ahmadi A, Hedayati MA. Virulence genes, phylogenetic analysis, and antimicrobial resistance of Escherichia coli isolated from urinary tract infection in hospitalized patients and outpatients. J Appl Genet 2022; 63: 805-813.
10. Wei L, Wu L, Wen H, Feng Y, Zhu S, Liu Y, et al. Spread of carbapenem-resistant Klebsiella pneumoniae in an intensive care unit: a whole-genome sequence-based prospective observational study. Microbiol Spectr 2021; 9(1): e0005821.
11. Wyres KL, Holt KE. Klebsiella pneumoniae as a key trafficker of drug resistance genes from environmental to clinically important bacteria. Curr Opin Microbiol 2018; 45: 131-139.
12. Ahmadi M, Ranjbar R, Behzadi P, Mohammadian T. Virulence factors, antibiotic resistance patterns, and molecular types of clinical isolates of Klebsiella pneumoniae. Expert Rev Anti Infect Ther 2022; 20: 463-472.
13. Saha U, Gondi R, Patil A, Saroj SD. CRISPR in modulating antibiotic resistance of ESKAPE pathogens. Mol Biotechnol 2023; 65: 1-16.
14. Morshedzadeh F, Ghanei M, Lotfi M, Ghasemi M, Ahmadi M, Najari-Hanjani P, et al. An update on the application of CRISPR technology in clinical practice. Mol Biotechnol 2024; 66: 179-197.
15. Kadkhoda H, Gholizadeh P, Ghotaslou R, Nabizadeh E, Pirzadeh T, Rezaee MA, et al. Role of CRISPR-cas system on virulence traits and carbapenem resistance in clinical Klebsiella pneumoniae isolates. Microb Pathog 2025; 199: 107151.
16. Li H-Y, Kao C-Y, Lin W-H, Zheng P-X, Yan J-J, Wang M-C, et al. Characterization of CRISPR-Cas systems in clinical Klebsiella pneumoniae isolates uncovers its potential association with antibiotic susceptibility. Front Microbiol 2018; 9: 1595.
17. Kamruzzaman M, Iredell JR. CRISPR-Cas system in antibiotic resistance plasmids in Klebsiella pneumoniae. Front Microbiol 2020; 10: 2934.
18. Long J, Zhang J, Xi Y, Zhao J, Jin Y, Yang H, et al. Genomic insights into CRISPR-harboring plasmids in the Klebsiella genus: distribution, backbone structures, antibiotic resistance, and virulence determinant profiles. Antimicrob Agents Chemother 2023; 67(3): e0118922.
19. Kadkhoda H, Gholizadeh P, Kafil HS, Ghotaslou R, Pirzadeh T, Rezaee MA, et al. Role of CRISPR-Cas systems and anti-CRISPR proteins in bacterial antibiotic resistance. Heliyon 2024; 10. doi: 10.1016/j.heliyon.2024.e34692.
20. Shen J, Lv L, Wang X, Xiu Z, Chen G. Comparative analysis of CRISPR‐Cas systems in Klebsiella genomes. J Basic Microbiol 2017; 57: 325–336.
21. Zhou Y, Tang Y, Fu P, Tian D, Yu L, Huang Y, et al. The type IE CRISPR-Cas system influences the acquisition of bla KPC-IncF plasmid in Klebsiella pneumonia. Emerg Microbes Infect 2020; 9:1011-1022.
22. Tang Y, Fu P, Zhou Y, Xie Y, Jin J, Wang B, et al. Absence of the type IE CRISPR-Cas system in Klebsiella pneumoniae clo nal complex 258 is associated with dissemination of IncF epidemic resistance plasmids in this clonal complex. J Antimicrob Chemother 2020; 75: 890-895.
23. Makarova KS, Koonin EV. Annotation and classification of CRISPR-Cas systems. CRISPR: methods and protocols 2015; 1311: 47–75.
24. Kadkhoda H, Gholizadeh P, Ghotaslou R, Pirzadeh T, Ahangarzadeh Rezaee M, Nabizadeh E, et al. Prevalence of the CRISPR-cas system and its association with antibiotic resistance in clinical Klebsiella pneumoniae isolates. BMC Infect Dis 2024; 24: 554.
25. Yousefi L, Kadkhoda H, Shirmohammadi M, Moaddab SY, Ghotaslou R, Pirzadeh T, et al. CRISPR-like sequences association with antibiotic resistance and biofilm formation in Helicobacter pylori clinical isolates. Heliyon 2024; 10. doi: 10.1016/j.heliyon.2024.e26809.
26. Liao W, Liu Y, Chen C, Li J, Du F, Long D, et al. Distribution of CRISPR-Cas systems in clinical carbapenem-resistant Klebsiella pneumoniae strains in a Chinese tertiary hospital and its potential relationship with virulence. Microb Drug Resist 2020; 26: 630-636.
27. Al Bshabshe A, Al-Hakami A, Alshehri B, Al-Shahrani KA, Alshehri AA, Al Shahrani MB, et al. Rising Klebsiella pneumoniae infections and its expanding drug resistance in the intensive care unit of a tertiary Healthcare Hospital, Saudi Arabia. Cureus 2020; 12. doi: 10.7759/cureus.10060.
28. Alhazmi W, Al-Jabri A, Al-Zahrani I. The molecular characterization of nosocomial carbapenem-resistant Klebsiella pneumoniae co-Harboring bla NDM and bla OXA-48 in Jeddah. Microbiol Res 2022; 13: 753-764.
29. Oteo J, Hernández JM, Espasa M, Fleites A, Sáez D, Bautista V, et al. Emergence of OXA-48-producing Klebsiella pneumoniae and the novel carbapenemases OXA-244 and OXA-245 in Spain. J Antimicrob Chemother 2013; 68: 317-321.
30. Stewart A, Harris P, Henderson A, Paterson D. Treatment of infections by OXA-48-producing Enterobacteriaceae. Antimicrob Agents Chemother 2018; 62(11): e01195-18.
31. Tu MM, Carfrae LA, Rachwalski K, French S, Catacutan D, Gordzevich R, et al. Exploiting the fitness cost of metallo-β-lactamase expression can overcome antibiotic resistance in bacterial pathogens. Nat Microbiol 2025; 10: 53-65.
32. Li H, Xie Y, Chen F, Bai H, Xiu L, Zhou X, et al. Amplification-free CRISPR/Cas detection technology: challenges, strategies, and perspectives. Chem Soc Rev 2023; 52: 361-382.
33. Bhatia S, Yadav SK. CRISPR-Cas for genome editing: classification, mechanism, designing and applications. Int J Biol Macromol 2023; 238: 124054.
34. Pursey E, Dimitriu T, Paganelli FL, Westra ER, Van Houte S. CRISPR-Cas is associated with fewer antibiotic resistance genes in bacterial pathogens. Philos Trans R Soc Lond B Biol Sci 2022; 377: 20200464.
35. Dogan O, Vatansever C, Atac N, Albayrak O, Karahuseyinoglu S, Sahin OE, et al. Virulence determinants of colistin-resistant K. pneumoniae high-risk clones. Biology (Basel) 2021; 10: 436.
36. Lam MM, Wyres KL, Judd LM, Wick RR, Jenney A, Brisse S, et al. Tracking key virulence loci encoding aerobactin and salmochelin siderophore synthesis in Klebsiella pneumoniae. Genome Med 2018; 10: 77.
37. Nazir A, Zhao Y, Li M, Manzoor R, Tahir RA, Zhang X, et al. Structural genomics of repA, repB1-carrying IncFIB family pA1705-qnrS, P911021-tetA, and P1642-tetA, multidrug-resistant plasmids from Klebsiella pneumoniae. Infect Drug Resist 2020; 13: 1889-1903.
38. Ferreira R, Da Silva B, Rezende G, Nakamura-Silva R, Pitondo-Silva A, Campanini E, et al. High prevalence of multidrug-resistant Klebsiella pneumoniae harboring several virulence and β-lactamase encoding genes in a Brazilian intensive care unit. Front Microbiol 2018; 9: 3198.
39. Valkovicova L, Valkova D, Vavrova S, Alekhina O, Hoang VP, Jezna M, et al. The role of TerW protein in the tellurite resistance of uropathogenic Escherichia coli. Biologia 2011; 66: 565-573.
40. Suzuki K, Tanabe T, Moon Y-H, Funahashi T, Nakao H, Narimatsu S, et al. Identification and transcriptional organization of aerobactin transport and biosynthesis cluster genes of Vibrio hollisae. Res Microbiol 2006; 157: 730-740.
41. Lymboussaki A, Pignatti E, Montosi G, Garuti C, Haile DJ, Pietrangelo A. The role of the iron responsive element in the control of ferroportin1/IREG1/MTP1 gene expression. J Hepatol 2003; 39: 710-715.
42. Bolourchi N, Naz A, Sohrabi M, Badmasti F. Comparative in silico characterization of Klebsiella pneumoniae hypervirulent plasmids and their antimicrobial resistance genes. Ann Clin Microbiol Antimicrob 2022; 21: 23.
43. Lai Y-C, Peng H-L, Chang H-Y. RmpA2, an activator of capsule biosynthesis in Klebsiella pneumoniae CG43, regulates K2 cps gene expression at the transcriptional level. J Bacteriol 2003; 185: 788-800.
44. Zhu J, Wang T, Chen L, Du H. Virulence factors in hypervirulent Klebsiella pneumoniae. Front Microbiol 2021; 12: 642484.
| Files | ||
| Issue | Vol 18 No 1 (2026) | |
| Section | Original Article(s) | |
| DOI | https://doi.org/10.18502/ijm.v18i1.20901 | |
| Keywords | ||
| Klebsiella pneumoniae CRISPR-cas systems Drug resistance Virulence factors Gene expression regulation | ||
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How to Cite
1.
Saedi S, Nezhadi J, Feizi H, Memar MY, Arefi V, Kadkhoda H. A comparative analysis of CRISPR systems, virulence factors, and antibiotic resistance genes in carbapenem-sensitive and carbapenem-resistant Klebsiella pneumoniae. Iran J Microbiol. 2026;18(1):1-13.
