ASM Microbe
ASM Microbe
June 23, 2019
1 min read

Resistant bacterial strain persists in California hospital for over 3 years

You've successfully added to your alerts. You will receive an email when new content is published.

Click Here to Manage Email Alerts

We were unable to process your request. Please try again later. If you continue to have this issue please contact

SAN FRANCISCO — Epidemiologic data and whole genome sequencing revealed a more than 3-year-long transmission of a single bacterial strain with antibiotic-resistant genes in a northern California hospital, according to data presented at ASM Microbe.

The strain of New Delhi metallo-beta-lactamase (NDM)-producing Klebsiella pneumoniae was introduced in the hospital’s ICU in 2013, researchers reported.

“This type of resistance is still relatively rare in the United States to the point that we are on high alert to prevent any further spread,” Varvara Kozyreva, PhD, chief of the genotyping unit in the microbial diseases laboratory program at the California state health department, told Infectious Disease News. “The hospital kept [seeing] this NDM type of isolate ... and we continued to sequence them, not expecting them to match over years.”

According to the study, the researchers identified eight patients with NDM-producing K. pneumoniae between 2013 and 2015. An initial cluster of four patients had overlapping stays in the adult ICU over a 1-month period and one patient from the initial cluster remained in the ICU for 2 years, during which time four more cases were identified, the researchers reported.

Test results showed that the eight isolates were highly related by whole genome sequencing (WGS). According to Kozyreva and colleagues, “the blaNDM-1 gene was located on the chromosome, suggesting recurrent transmission of a clonal resistant strain rather than transfer of plasmids between strains.”

Kozyreva said there are probably more transmission events like this that are missed.

“The surveillance of [carbapenem-resistant Enterobacteriaceae] isolates using WGS is really beneficial to identify transmission events in the hospitals. Hospitals should be on the lookout for them, especially because those pathogens can circulate throughout hospitals and transmit from patient to patient for a long term,” Kozyreva said. “Overall, we need better surveillance. This pathogen is here and it’s here to stay. Without knowing it’s there — we won’t be able to stop it.” – by Caitlyn Stulpin


Kozyreva A, et al. Whole genome sequencing demonstrated sustained transmission of a single strain of New Delhi metallo-beta-lactamase (NDM)-producing Klebsiella pneumoniae in a northern California hospital. Presented at: ASM Microbe; June 20-24, 2019; San Francisco.

Disclosures: The authors report no relevant financial disclosures.