Resistome-based surveillance identifies potential outbreaks of KPC-producing bacteria

SAN DIEGO — A resistome-based surveillance system used to detect potential outbreaks identified two dominant resistome types of Klebsiella pneumoniae carbapenemase-producing Enterobacteriaceae in the Chicago region, according to data presented at IDWeek 2015.

“Since [Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacteriaceae] can carry multiple beta-lactamase genes, beta-lactamase resistome types can be markers indicating how strains are related and can detect a potential outbreak,” Michael Y. Lin, MD, MPH, assistant professor of medicine at Rush University Medical Center, said in a press release. “Resistant bacteria typically affect the sickest patients, and accurate and early surveillance data is a key part of our efforts in the Chicago area to successfully manage infections and prevent outbreaks.”

Lin and colleagues evaluated 363 KPC-producing Enterobacteriaceae collected from 177 distinct hospital point prevalence rectal culture surveys between 2010 and 2014. Beta-lactamase resistome genes were characterized using the Acuitas Resistome Test (OpGen), which targeted 49 gene families, including carbapenemase, extended-spectrum beta-lactamase (ESBL), plasmid-mediated AmpC (pAmpC) and narrow spectrum beta-lactamase gene families. Resistome types were described by unique combinations of beta-lactamase genes; minority resistome types were established in temporal-spatial clusters of two or more identical KPC-producing Enterobacteriaceae that were collected from the same facility and survey date.

According to the data, 86% of KPC-producing Enterobacteriaceae were K. pneumoniae, 7% were Escherichia coli and 6% were Enterobacter species. The isolates contained a median of five beta-lactamase genes. Forty-six percent of the isolates contained SHV-type ESBL genes, 5% contained TEM-type ESBL genes, 3% contained CTX-M–type ESBL genes, and 13% contained pAmpC-type genes.

Thirty-eight resistome types were identified in 23 resistance genes, with two types accounting for 71% of all isolates. Fifty-seven percent of the isolates found in minority resistome types (n = 69) could be grouped into clusters.

Although whole-genome sequencing would be needed to determine the chain of transmission, the researchers concluded that facility clustering with a resistome-based surveillance system can improve infection control. – by Stephanie Viguers

Reference:

Lin MY, et al. Abstract 1378. Presented at: IDWeek; Oct. 7-11, 2015; San Diego.

Disclosure: Lin reports no relevant financial disclosures. Two researchers report being paid employees of OpGen, and one researcher reports being a paid employee of Chlorox.