Study: Resistant gram-negative bacteria common in nursing homes

A new meta-analysis suggests that about a quarter of nursing home residents are colonized with multidrug-resistant gram-negative bacteria (MDR-GNB), which the authors say points up the need for better infection control programs in facilities for the elderly.

In recent studies that met the authors' quality criteria, an overall average of 27% of nursing home residents were found to carry MDR-GNB, according to their report in the May issue of the American Journal of Infection Control (AJIC).

Gram-negative bacteria cause bloodstream and wound infections, pneumonia, and meningitis in healthcare settings and are increasingly resistant to most antibiotics, according to the Centers for Disease Control and Prevention (CDC). Examples of the pathogens include Klebsiella pneumoniae, Escherichia coli, Acinetobacter species, and Pseudomonas aeruginosa.

Prevalence ranged up to 59%

The investigators conducted a systematic review of relevant studies published from January 2005 through February 2016, according to their report. Of 327 relevant studies, 12 met their criteria for review. Among these, the prevalence of MDR-GNB colonization in nursing home residents ranged from 11.2% to 59.1%, with a pooled average, representing data from 2,720 residents, of 27% (95% confidence interval, 15.2% to 44.1%).

E coli was the most common MDR-GNB found, accounting for 42% of samples. The leading colonization site was the rectum, followed by the nose, sputum, urinary tract, and wounds, according to the report.

Most of the studies were conducted in the United States, and those showed an average colonization prevalence of 38%, the authors said. In studies from two other countries, Korea and Germany, the prevalence was significantly lower at 14%. The researchers found no significant differences in prevalence by year of publication.

In other findings, 9 of the 12 studies identified specific factors that were linked with increased MDR-GNB colonization risk, according to a press release from the Association for Professionals in Infection Control and Epidemiology (APIC), which publishes AJIC.

The risk factors included advanced age, gender, co-morbid chronic diseases, a history of recurrent hospitalization, increased interaction with healthcare workers, frequent antimicrobial exposure, delayed initiation of effective antibiotic therapy, the presence of medical devices, decreased functional status, advanced dementia, inability to walk, fecal incontinence, and severe sepsis present on admission to a hospital. (The analysis included two studies involving patients with MDR-GNB infections who were admitted to acute care hospitals from nursing homes.)

Hospital screening suggested

The authors believe the study to be the first systematic attempt to estimate the prevalence of MDR-GNB colonization in nursing home residents. Calling the findings "concerning," they wrote that screening on hospital admission may be needed to identify colonized or infected nursing home residents. "It is essential to reexamine the efficacy of infection control practices in [nursing homes] and implement policies specific to this setting that can reduce the prevalence of MDR-GNB," they added.

"This study underscores the importance of having strong infection prevention programs in all nursing homes and long-term care facilities," APIC President Linda Greene, RN, MPS, commented in the group's press release. "Understanding the dynamics and cause of MDR-GNB transmission is crucial to identifying effective infection control strategies specific to these settings."

Prevention and management of MDR-GNB in nursing homes are complicated and require extensive infection control resources because of challenges such as understaffing, fewer resources, insufficient training, and inadequate surveillance, APIC officials said.

Nursing homes face stewardship mandate

The new findings come just a few months after the federal government began requiring nursing homes and assisted-living facilities that receive Medicare and Medicaid funds to have antibiotic stewardship programs to counter the spread of resistant bacteria. The rule issued by the Centers for Medicare and Medicaid Services took effect last November.

The CDC has estimated that 70% of nursing home residents receive one or more courses of antibiotic treatment each year, and most experts agree that efforts to limit the spread of resistant bacteria need to address antibiotic use in long-term care facilities. In a CIDRAP News story last September, one expert estimated that 40% to 70% of the antibiotic prescriptions for nursing home residents are inappropriate and put residents at risk for resistant infections.

The need for careful antibiotic stewardship in nursing homes was also stressed in a report last year by the Pew Charitable Trusts. It said that a significant share of antibiotic prescriptions in nursing homes involve inappropriate drugs or are entirely unnecessary. While antibiotic stewardship programs in hospitals have increased in the past decade, the report said, their adoption in nursing homes has been limited, "often because of difficulties in tailoring [such programs] to meet the unique resource and staffing limitations of these institutions."

Aliyu S, Smaldone A, Larson E. Prevalence of multidrug-resistant gram-negative bacteria among nursing home residents: a systematic review and meta-analysis. Am J Infect Control 2017 May 1;45(5):512-8 [Full text]

See also:

Apr 27 APIC press release
CDC information on gram-negative bacteria
Oct 4, 2016, CIDRAP News story on mandate for antibiotic stewardship in nursing homes
Mar 7, 2016, Pew report

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