A low incidence of antibiotic-resistant Enterobacteriaceae bacteria was found in a study of Rhode Island nursing home residents admitted to acute care facilities, but researchers said a better understanding of risk factors associated with carriage of carbapenem-resistant gram-negative bacteria among nursing home patients is needed.
Dr. Cheston B. Cunha of the division of infectious diseases at Rhode Island Hospital in Providence and colleagues investigated the prevalence of carbapenem-resistant Enterobacteriaceae (CRE) and carbapenemase-producing Enterobacteriaceae (CPE) in fecal samples of asymptomatic nursing home residents during hospitalization. Their results were published online in the American Journal of Infection Control (2015 Nov 24. doi: 10.1016/j.ajic.2015.09.019)
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The researchers conducted a point prevalence survey of 500 hospitalizations of nursing home residents admitted to two Providence, R.I., hospitals. Risk factors associated with CRE carriage were determined by a case-control study. They obtained cultures on 404 patients with 96 readmissions for a total of 500 rectal swabs. The study population consisted of 40% men with a mean age of 80 years.
In total, 23 patients with 30 isolates (4.6%) grew carbapenem resistant or carbapenemase-producing gram-negative bacteria. Of those, seven isolates (1.4%) were CPE or CRE with two isolates (0.4%) that were Citrobacter freundii that contained Klebsiella pneumoniae carbapenemase.
On univariate analysis the researchers found the use of a gastrostomy tube was associated with fecal carriage of CRE (P = .4).
“We found seven CRE-CPE [isolates] among 500 hospital admissions from local nursing homes; however, only two, both C. freundii isolates, contained potentially transmissible carbapenem-resistance genes,” the authors said, noting that the results suggest that in their region, the levels of CPE and CRE carriage are low in nursing home patients.
Furthermore, the investigators suggested that antibiotic resistance is likely promoted by overtreatment with antibiotics, with nursing home residents being at risk for transmission of multidrug-resistant bacteria. “Active infection with CRE and CPE is associated with a high mortality; therefore, efforts to control their spread is of paramount importance,” the authors wrote.
Several limitations of the study were highlighted, including its retrospective design, that it was underpowered to assess risk factors, and that the study population may have been a sicker group of patients because only hospitalized patients were included.
Coauthor Fred C. Tenover, Ph.D., reported employment by Cepheid, and coauthor Ryan Chan reported employment by Cepheid and GeneWeave Biosciences.