Prevalence of and Risk Factors for Multidrug-ResistantAcinetobacter baumanniiColonization Among High-Risk Nursing Home Residents

Abstract

OBJECTIVE To characterize the epidemiology of multidrug-resistant (MDR) Acinetobacter baumannii colonization in high-risk nursing home (NH) residents. DESIGN Nested case-control study within a multicenter prospective intervention trial. SETTING Four NHs in Southeast Michigan. PARTICIPANTS Case patients and control subjects were NH residents with an indwelling device (urinary catheter and/or feeding tube) selected from the control arm of the Targeted Infection Prevention study. Cases were residents colonized with MDR (resistant to ≥3 classes of antibiotics) A. baumannii; controls were never colonized with MDR A. baumannii. METHODS For active surveillance cultures, specimens from the nares, oropharynx, groin, perianal area, wounds, and device insertion site(s) were collected upon study enrollment, day 14, and monthly thereafter. A. baumannii strains and their susceptibilities were identified using standard microbiologic methods. RESULTS Of 168 NH residents, 25 (15%) were colonized with MDR A. baumannii. Compared with the 143 controls, cases were more functionally disabled (Physical Self-Maintenance Score >24; odds ratio, 5.1 [95% CI, 1.8–14.9]; P < .004), colonized with Proteus mirabilis (5.8 [1.9–17.9]; P < .003), and diabetic (3.4 [1.2–9.9]; P < .03). Most cases (22 [88%]) were colonized with multiple antibiotic-resistant organisms and 16 (64%) exhibited co-colonization with at least one other resistant gram-negative bacteria. CONCLUSION Functional disability, P. mirabilis colonization, and diabetes mellitus are important risk factors for colonization with MDR A. baumannii in high-risk NH residents. A. baumannii exhibits widespread antibiotic resistance and a preference to colonize with other antibiotic-resistant organisms, meriting enhanced attention and improved infection control practices in these residents.

Multidrug-resistant organism carriage among residents from residential care homes for the elderly in Hong Kong: a prevalence survey with stratified cluster sampling

“…There were no subsequent outbreaks reported. Internationally, the prevalence of MDRA is much lower than that reported in studies from the US (prevalence of multidrug-resistant A baumannii was 15.0%) 40 and Australia (prevalence of multidrug-resistant A baumannii was 5.2%). 41 In RCHEs, the prevalence of MRSA is rising rapidly, and that of MDRA has the potential to rise.…”

Decolonization in Prevention of Health Care-Associated Infections

“…Cocolonization with more than one type of bacteria is common because some risk factors for colonization are common to multiple MDROs (30). One recent study found that among nursing home residents with indwelling devices, those colonized with multidrug-resistant Acinetobacter baumannii had a high likelihood of also being colonized with another antibiotic-resistant Gram-negative pathogen (31). Similarly, other studies have found that ICU patients colonized with VRE are often cocolonized with ESBLproducing bacteria or with MRSA (30,32).…”

“…Bacterial colonization can be categorized as persistent carriage, intermittent carriage, or noncarriage (14). One study of nursing home residents with indwelling devices found that of the 15% who were colonized with multidrug-resistant Acinetobacter baumannii, nearly half of those colonizations recurred over time (31). Other studies have shown that among S. aureus nasal carriers, approximately 40% are persistently colonized and 60% are intermittently colonized (14).…”

Emerging antibiotics for community-acquired pneumonia

“…Interestingly, in a case-control study in the USA that aimed to characterize the epidemiology of MDR A. baumannii colonization in high-risk nursing home residents, 15% (n = 25) of residents were noted to be colonized, with all isolates being resistant to cephalosporins, monobactam (aztreonam), and quinolones. They reported the main risk factors for MDR A. baumannii as functional disability, Proteus mirabilis colonization, and diabetes mellitus [25].…”