Background and study aim: Klebsiella pneumonia, particularly the hypervirulent (hvKP) strains, are resistant to antibiotics and cause infections difficult to treat. This study aimed to compare clinical presentation, severity of infection, resistance profiles, virulence factors, genotypes and clinical outcomes of the classical (CKP) and the (HvKP) isolates in patients with Community acquired pneumonia (CAP).
Patients and Methods: Ninety nine patients with CAP were enrolled in this study, sputum samples were taken, processed and cultured for isolation of K. pneumonia. Isolated K. pneumonia were identified by conventional methods and PCR. Hyperviruelnce was detected by string test and PCR. Virulence genes were detected using multiplex PCR and finally Genotyping was done using ERIC PCR.
Results: A total of 99 K. pneumoniae isolates were recovered, 29 (29.3%) were identified as hvKP while 70 (70.7%) were cKP. Pneumonia caused by Hvkp isolates showed more intensive care unit admission, vasopressor use, and need for mechanical ventilation while mortality doesn't differ between Ckp and Hvkp isolates.  Capsular serotypes K1, K2 and K5 were more prevalent in hvKP. However, capsular serotype K20 was more prevalent in cKP. Among all isolates, entB and ycfm (89.8% and 94.9%, respectively) were the most common virulence genes. rmpA, wcaG, uge and kfu were more predominant in hvKP isolates. Isolates were categorized into 12 ERIC types. Conclusion: Our findings support the effectiveness and applicability of the ERIC-PCR technique for molecular typing, epidemiological investigation of nosocomial infections, and analysis of genetic diversity among hospital pathogens, including K. pneumoniae strains. K. pneumoniae strains obtained from Egyptian hospitals displayed a considerable amount of variability in their antibiotic resistance and ERIC profiles.