China reports increasing incidence of hypervirulent K. pneumoniae
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Hypervirulent variants of Klebsiella pneumoniae are emerging, and although most exhibit susceptibility to antimicrobials, resistance is increasing, researchers from China have found.
The researchers conducted a retrospective study on 88 patients with K. pneumoniae who were hospitalized from April 2010 to June 2012 at the Beijing You’an Hospital. They made clinical and molecular comparisons between patients who had classic K. pneumoniae and patients who had hypervirulent K. pneumoniae.
Among the isolates, 29 were hypervirulent K. pneumoniae and 59 were classic K. pneumoniae. More community-acquired infections were identified in patients with hypervirulent strains. Patients with hypervirulent strains were more likely to have liver abscesses, alcoholic hepatitis and metastatic infection. Sputum isolation and HIV infection appeared protective against hypervirulent K. pneumoniae. Genetically, the rmpA gene was strongly associated with hypervirulent K. pneumoniae, as were the capsule antigens K1 and K2. On multivariate analysis, the rmpA gene and community-acquired infection were independent risk factors for hypervirulent K. pneumoniae.
More classic K. pneumoniae strains were resistant to antimicrobials, except for ampicillin, piperacillin-tazobactam (Zosyn, Wyeth Pharmaceuticals), chloramphenicol and carbapenems. All hypervirulent strains were resistant to ampicillin, and resistance to all antimicrobials, except carbapenems and amikacin, was found in some strains, 17% of which expressed extended spectrum beta-lactamase. From April 2010 to June 2012, the proportion of strains exhibiting antimicrobial resistance among these strains rose from 15.4% to 25%.
“These data indicate that this group of life-threatening pathogens warrants further investigation to avert potential damage that may be caused in the future,” the researchers wrote.
Disclosure: The researchers report no relevant financial disclosures.