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BACKGROUND:Klebsiella pneumoniae causes both nosocomial and community-associated infections. Hypervirulent K. pneumoniae (hvKP), new variant of K. pneumoniae, can cause invasive infections in young healthy individuals as well as in the immunocompromised population. Hypervirulent strains frequently belong to capsular serotypes K1 or K2. Emergence of antimicrobial resistance in hvKP is a cause for concern.AIM AND OBJECTIVE:The present study was done to detect the K1 and K2 serotypes among clinical isolates of K. pneumoniae, spectrum of infections caused by them and presence of common beta-lactamases encoding genes in them.MATERIALS AND METHODS:A total of 370 isolates of K. pneumoniae, isolated from various clinical samples over a period of 1 year was included in this study. Antibiotic susceptibility testing to various classes of antimicrobials was done as per Clinical and Laboratory Standard Institute guidelines. The presence of K2A (specific to serotype K2), magA (specific to serotype K1), and rmpA genes was detected by multiplex polymerase chain reaction (PCR). Extended-spectrum beta-lactamases (TEM, SHV, and CTX-M), plasmid-mediated AmpCs (MOX, CIT, DHA, ACC, EBC, and FOX), and carbapenemase genes (IMP, VIM, NDM, KPC, and OXA-48) were also determined by PCR.RESULTS:Among the 370 isolates, 8 harbored K2A gene and one harbored magA. rmpA gene was detected in three isolates along with K1 or K2 serotypes. Seven K2A-positive isolates were resistant to one or more classes of antimicrobials. The studied ESBL genes were present in four isolates. Two isolates harbored carbapenemase genes (NDM-1, OXA-48) along with ESBLs.CONCLUSION:K2 serotype is more prevalent among hvKP isolates. They can harbor ESBLs and Carbapenemase genes. K1 serotype is rather uncommon in K. pneumoniae. Acquisition of multidrug-resistant genes by these strains adds to their virulence and limits the treatment options.

BACKGROUND: Klebsiella pneumoniae (K. pneumoniae) is an important nosocomial pathogen, and the emergence of multidrug resistance in these organisms limits the treatment options for serious infections caused by them. K. pneumoniae carbapenemase (KPC) is one of the clinically significant Class A beta-lactamases. AIM AND OBJECTIVE: This study was aimed to detect the KPC and its coexistence with other beta-lactamases in K. pneumoniae. MATERIALS AND METHODS: A total of 370 isolates, collected over a period of 1 year, were included in this study. The source of these isolates were urine (n = 170), exudative specimens (n = 132), respiratory secretions such as bronchial wash, endotracheal aspirate, and pleural fluid (n = 38), and blood (n = 30). For all the isolates, antibiotic susceptibility tests by disc diffusion, modified Hodge test, and KPC screening test were done. Polymerase chain reaction (PCR) was performed for the detection of KPC and the copresence of other beta-lactamases genes. RESULTS: Among the 370 isolates, 41 were resistant to the carbapenem by disc diffusion and minimum inhibitory concentration tests. Screen test using ertapenem and the boronic acid disk was positive in 14 isolates. Only one isolate harbored KPC gene by PCR, and it was co-produced with SHV-12 and CTX-M-15. CONCLUSION: PCR remains the gold standard for detection of KPC compared with any other phenotypic methods. Early detection of these genes helps in initiating proper antibiotic treatment.

BACKGROUND: Carbapenems are used for the treatment of serious infections caused by multidrug-resistant Klebsiella pneumoniae. Resistance to carbapenems in K. pneumoniae is mainly due to metallo-beta-lactamases (NDM, IMP, and VIM) and class D oxacillinase (OXA-48-like). AIM AND OBJECTIVE: This study was undertaken to detect the genes encoding for carbapenemase in K. pneumoniae and to determine the clonal relatedness of selected isolates of K. pneumoniae producing NDM and OXA-48 by pulsed-field gel electrophoresis method (PFGE). MATERIALS AND METHODS: The isolates were collected over a period of 1 year. A total of 370 clinically significant, nonduplicate isolates of K. pneumoniae were included in this study. Phenotypic tests for the detection of carbapenemases were performed for all the isolates. Polymerase chain reaction (PCR) was carried out for the detection of carbapenemase genes such as blaKPC, blaIMP, blaVIM,blaNDM, and blaOXA-48. PFGE was performed, and the PFGE profiles were analyzed and compared using BioNumerics version 7.6. RESULTS: Of the 370 isolates of K. pneumoniae, carbapenemase genes were detected in 13.78% (51/370). blaOXA-48was the prevalent gene detected followed by blaNDMand blaKPC. Thirty strains of K. pneumoniae selected by PFGE analysis were divided into five clusters (A, B, C, D, and E). Cluster C was the major type detected carrying blaNDMand blaOXA-48genes.CONCLUSION:blaOXA-48was the most prevalent gene detected in this study. PCR is useful in detecting carbapenemase genes, especially blaNDM, which may show false susceptibility to carbapenems. There was no direct correlation detected between PFGE profiles and antibiotic susceptibility pattern. PFGE has revealed the genomic diversity among isolates, thereby suggesting heterogeneity in strain circulation within intensive care unit and wards of the hospital. Monitoring and molecular typing is essential to curtail the spread of multidrug-resistant strains and control the outbreaks of infection.

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