Residence in Long Term Care Facilities as a Risk for HCAP: A Review of Culture Resistance Attributable to Facility as Compared to Antibiotic Selection Pressure

Background: The 2005 ATS/IDSA guidelines for the management of healthcare-associated pneumonia (HCAP) recommend that residents of nursing home or long-term care facilities (LTCFs) be treated with broad-spectrum empiric antibiotic regimen given an increased mortality rate in this population. However, broad-spectrum antibiotics carry higher antibiotic-associated risks, making accurate identification of high-risk patients essential.

Objective: Our aim was to identify the prevalence of resistant cultures from the residents of four LTCFs (two skilled nursing facilities, two intermediate care psychiatric institutions) as compared with a high-rise apartment complex, as well as to determine whether a calculated measure of antibiotic selection pressure was associated with resistance rates.

Methods: Hospital database address registries retrospectively identified inpatients whose addresses matched one of the above five locations admitted to one tertiary care center in the past five years who also had a positive bacterial culture with sensitivity testing performed. Cultures were excluded if they had a hospital stay for 2 or more days within the last 90 days, intravenous therapy including antibiotics or dialysis or wound care within the past 30 days, or culture collection greater than 48 hours after hospital admission. Urine cultures from patients with chronic bladder instrumentation, screening cultures of body orifices for MRSA and VRE, and repeat positive cultures of the same organism within 90 days were also excluded. A sensitive isolate was determined by sensitivity of the organism to typical inpatient community acquired pneumonia therapy (sensitivity to Ceftriaxone), if available, or by previously defined criteria from the literature. Facility antibiotic exposure for the four LTCFs was estimated by calculating a daily defined dose (DDD) per 100 bed-days for each facility in 2009, which was compared in unadjusted linear regression to the calculated resistance rate.

Results: 2536 cultures were reviewed, and 1767 were excluded, leaving 769 (30%) cultures meeting the inclusion criteria. Resistance rates were quite variable, with rates of two intermediate care facilities at 7.8% and 31.3%, while the skilled nursing facilities’ resistance rates were calculated at 9.7% and 18.2%.Two facilities had higher and two had lower rates than the community control group (13.9%). Linear regression showed no correlation between DDD of antibacterials per 100 bed-days and the percentage of resistant rates among residents of the LTCFs (p = 0.52).

Conclusions: Using residence in a long-term care facility as a risk for HCAP may over- or under-state risk of resistance, and DDD of antibacterials per 100 bed-days did not correlate with resistance. More study is needed to identify patients at highest risk for complicated pneumonia.