The Centers for Disease Control and Prevention (CDC) have reported a concerning discovery: the identification of a carbapenemase-producing hypervirulent Klebsiella pneumoniae (K. pneumoniae) isolate in the United States, known to carry a plasmid with the bla_KPC-2 gene. This isolate combines drug-resistance with increased virulence, a combination that could herald a new wave of bacterial threat in healthcare settings. This article delves into the implications of this finding and the necessary steps to combat this emerging health risk.

Background on the Superbug

Klebsiella pneumoniae is a common pathogen associated with a variety of infections, including pneumonia, bloodstream infections, and meningitis, particularly in healthcare environments. Traditionally, the treatment for K. pneumoniae involved carbapenem antibiotics, a class known for its effectiveness against multidrug-resistant organisms. However, with the advent of carbapenemase-producing strains, which can deactivate carbapenems, the treatment landscape has been complicated significantly.

Recent reports have compounded this challenge by documenting the emergence of hypervirulent strains of K. pneumoniae, far more aggressive than their traditional counterparts. These strains have been associated with severe outcomes, such as pyogenic liver abscesses, and show an increased potential to disseminate rapidly within communities.

The Discovery of Hypervirulent, Carbapenem-Resistant K. pneumoniae in the US

The detection of a carbapenemase-producing hypervirulent K. pneumoniae isolate in the US is a development that demands careful attention. According to a study published in “Antimicrobial Agents and Chemotherapy,” a team from the CDC alongside collaborators from the Minnesota Department of Public Health isolated a K. pneumoniae strain that exhibited both hypervirulence and resistance to carbapenem antibiotics. The isolate carried several virulence genes (rmpA, rmpA2, iroBCDN, peg-344, iucABCD-iutA) and produced the carbapenemase enzyme beta-lactamase KPC-2 (1). This marks a disturbing encounter with a pathogen that aligns drug-resistance with an enhanced ability to cause serious diseases.

DOI and Reference Insights

The detailed report is accessible via the DOI: 10.1128/AAC.00519-19, which provides critical insights into the genetic profiling and clinical ramifications of this isolate (2).

Public Health Implications

The emergence of this dual-threat pathogen has immediate implications for public health. Such isolates pose a challenge to existing infection control practices and necessitate an escalation in surveillance and prevention efforts. It also underscores the need to hasten the development of new antibiotics and invest in alternative therapeutic strategies, as our current armory could soon prove insufficient.

Clinical Relevance and Response

Clinicians must adopt heightened vigilance when treating infections potentially caused by K. pneumoniae, considering the potential for extensive drug resistance and enhanced disease progression. Standardized antimicrobial susceptibility tests and the application of molecular diagnostic tools can aid in prompt and accurate identification of these threatening isolates (3,4).

Research Perspective

Further research is needed to elucidate the mechanisms that enable the co-existence of virulence and resistance within a single K. pneumoniae isolate. Understanding the transmission dynamics and developing targeted therapies is crucial to averting a possible public health crisis. Researchers must investigate the genetic makeup of these superbugs to prevent their spread and mitigate their impact (5,6,7).

International Context

Globally, the prevalence of carbapenem-resistant, hypervirulent K. pneumoniae has been reported in several countries, such as China, where similar strains have led to fatal outcomes. The U.S. instance is not an isolated case, but part of an alarming global trend that calls for international collaboration in handling antimicrobial resistance (8,9).


1. Hypervirulent Klebsiella pneumoniae
2. Carbapenem-resistant bacteria
3. Antibiotic resistance CDC
4. Multidrug-resistant infections
5. Beta-lactamase KPC-2 gene

Concluding Remarks

The identification of a carbapenemase-producing hypervirulent K. pneumoniae in the US lends a new urgency to the need for robust antimicrobial stewardship and infection control measures. The combined virulence and resistance features present a formidable challenge to our healthcare system and underscore the importance of vigilant surveillance, prompt diagnosis, and judicious use of antimicrobials.

The healthcare community must respond proactively to ensure that the spread of these superbugs is contained, and research into new treatment modalities must be prioritized. The discovery detailed in this article is a call to action for clinicians, researchers, and policymakers alike to join forces and address the rising tide of antimicrobial-resistant infections.


1. Karlsson M, et al. Antimicrob Agents Chemother. 2019;63(7):e00519-19. DOI: 10.1128/AAC.00519-19.
2. Morrill HJ, et al. Open Forum Infect Dis. 2015;2:ofv050. DOI: 10.1093/ofid/ofv050.
3. Yigit H, et al. Antimicrob Agents Chemother. 2001;45:1151–1161. DOI: 10.1128/AAC.45.4.1151-1161.2001.
4. Tamma PD, et al. Clin Infect Dis. 2017;64:257–264. DOI: 10.1093/cid/ciw741.
5. Akova M, et al. Clin Microbiol Infect. 2012;18:439–448. DOI: 10.1111/j.1469-0691.2012.03823.x.
6. Bratu S, et al. Arch Intern Med. 2005;165:1430–1435. DOI: 10.1001/archinte.165.12.1430.
7. Lederman ER, et al. Am J Gastroenterol. 2005;100:322–331. DOI: 10.1111/j.1572-0241.2005.40310.x.
8. Gu D, et al. Lancet Infect Dis. 2018;18:37–46. DOI: 10.1016/S1473-3099(17)30489-9.
9. Zhang R, et al. Antimicrob Agents Chemother. 2016;60:709–711. DOI: 10.1128/AAC.02173-15.