Colonization with vancomycin-resistant Enterococcus faecium: comparison of a long-term-care unit with an acute-care hospital.

OBJECTIVE: To compare the epidemiology of vancomycin-resistant Enterococcus faecium (VRE) in a long-term-care unit and an acute-care hospital. DESIGN: Point-prevalence surveys for VRE rectal colonization of patients were carried out over a 21-month period in patients in a long-term-care unit and an acute-care hospital (medical ward and intensive-care units). The environment and hands of healthcare workers also were sampled for VRE. Contour-clamped homogeneous electric field (CHEF) electrophoresis was used to evaluate possible transmission among roommates and the relatedness of patient strains to those in the environment and on the hands of healthcare workers. SETTING: A 200-bed Veterans Affairs Medical Center with an attached 90-bed long-term-care unit. RESULTS: From December 1994 to January 1996, rectal VRE colonization of patients in the long-term-care unit increased significantly from 9% to 22%. In contrast, patients on the medical ward rarely were colonized after the first survey in December 1994, and only two intensive-care-unit patients were found to be colonized during the four surveys. The environment was contaminated persistently in the long-term-care unit. In the four surveys, carriage of VRE on hands of healthcare workers varied from 13% to 41%; 65% of healthcare workers with VRE found on their hands worked in the long-term-care unit. Seven different strains were identified by CHEF typing. Although the initial survey found only vanA strains, subsequent surveys showed vanB strains also were present. CONCLUSIONS: Residents of a long-term-care unit frequently were colonized with VRE, but infections were uncommon in this population. The environment of the long-term-care unit was contaminated with VRE, and VRE was found frequently on the hands of healthcare workers in this unit. Both vanA and vanB genotypes were found in this setting.

Identification of chromosomal location of mupA gene, encoding low-level mupirocin resistance in staphylococcal isolates.

Low- and high-level mupirocin resistance have been reported in Staphylococcus aureus. The expression of plasmid-encoded mupA is responsible for high-level mupirocin resistance. Low-level mupirocin-resistant strains do not contain plasmid-encoded mupA, and a chromosomal location for this gene has not previously been reported. We examined high- and low-level mupirocin-resistant S. aureus strains to determine if mupA was present on the chromosome of low-level-resistant isolates. Southern blot analysis of DNA from four mupirocin-resistant strains identified mupA in both high- and low-level mupirocin-resistant strains. Low-level mupirocin-resistant strains contained a copy of mupA on the chromosome, while the high-level mupirocin-resistant isolate contained a copy of the gene on the plasmid. PCR amplification of genomic DNA from each mupirocin-resistant strain resulted in a 1.65-kb fragment, the predicted product from the intragenic mupA primers. This is the first report of a chromosomal location for the mupA gene conferring low-level mupirocin resistance.

Health maintenance for the independent frail older adult: can it improve physical and mental well-being?

This descriptive study measured outcomes of a health maintenance programme (HMP) of regular exercise, health teaching and group participation on physical and mental well-being in a convenience sample of frail older adults living independently. Hand strength, range of motion (flexibility) and blood pressure were used as indicators of physical well-being. Self-esteem and life satisfaction were used as indicators of mental health. A pre-test/post-test design was used taking all measurements before starting the programme and after a 6-month interval of participation. Paired t-tests of mean change scores, with each participant acting as his or her own control, showed statistical improvement in systolic blood pressure and range of motion in right ankle and in self-esteem and life satisfaction using visual analogue scales. Clinical improvement was demonstrated in all measurements and by participant evaluation of the programme.

Mupirocin resistance: clinical and molecular epidemiology.

The antistaphylococcal activity of topical mupirocin has made it an attractive agent for the treatment of asymptomatic colonization with Staphylococcus aureus. Increasing use has been associated with the emergence of mupirocin resistance in staphyloccoci, and failure of therapy has been associated with the isolation of strains exhibiting high-level resistance (MIC > 500 micrograms/mL). Fortunately, low-level mupirocin resistance (MIC < 100 micrograms/mL) occurs most commonly. Because a novel gene encoding for mupirocin resistance resides in both low-level and high-level resistant strains, the emergence of low-level mupirocin resistance may not be as epidemiologically insignificant as previously thought.

Susceptibility of ciprofloxacin-resistant staphylococci and enterococci to clinafloxacin.

Clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus faecalis obtained from the Ann Arbor Veterans Affairs Medical Center within the last decade were tested for susceptibility to ciprofloxacin and clinafloxacin. For MRSA isolates, the minimum inhibitory concentrations (MICs) of ciprofloxacin were several fold higher than those noted with clinafloxacin. Prior to the introduction of the fluoroquinolones (1984-1985), all MRSA isolates were susceptible to ciprofloxacin and clinafloxacin. By 1993, virtually all MRSA isolates were resistant to ciprofloxacin and a 50-fold increase in the MIC50 and MIC90 for clinafloxacin was seen. In 1985-1986, most enterococcal isolates were susceptible to ciprofloxacin and clinafloxacin. By 1993, one-third of all enterococci were resistant to both ciprofloxacin and clinafloxacin. Fluoroquinolone resistance developed more quickly in enterococci that demonstrated high-level gentamicin resistance. Thus, cross-resistance between clinafloxacin and ciprofloxacin was seen; however, the lower MICs of clinafloxacin for MRSA may allow the use of this drug for some MRSA infections.

Colonization and transmission of high-level gentamicin-resistant enterococci in a long-term care facility.

OBJECTIVES: To assess the prevalence of high-level gentamicin-resistant enterococcus (HGRE) colonization, transmission patterns, and spectrum of illness among residents of a long-term care facility. DESIGN: Monthly surveillance for HGRE colonization of wounds, rectum, and perineum over a 1-year period. SETTING: A Veterans Affairs long-term care facility attached to an acute-care facility. PATIENTS: All 341 patients in the facility during the observation period. RESULTS: Over the 1-year period, 120 patients (35.2%) were colonized with HGRE at least once, with an overall monthly colonization rate of 20 +/- 1.5%. HGRE were isolated from rectum (12.8%), wounds (11.7%), and perineum (9.3%). Patients with the poorest functional status had the highest rate of colonization (P < 0.0005). HGRE-colonized patients were more likely to be colonized with methicillin-resistant Staphylococcus aureus (51% versus 25%; P < 0.0005). Seventy-four patients (21.7%) were colonized at admission or at the start of the study. Another 46 patients (13.5%) acquired HGRE during the study, including 36 who acquired HGRE while in the long-term care facility and 10 who were positive when transferred back from the acute-care hospital. Based on plasmid profiles, only two patients appeared to have isolates similar to those of current or previous roommates. Carriage of HGRE was transient in most cases. Only 20 patients were colonized for 4 or more months, and those patients usually carried different strains intermittently. Infections were infrequent, occurring in only 4.1% of total patients. CONCLUSIONS: In our long-term care facility, HGRE were endemic, and new acquisition of HGRE occurred frequently. However, only two patients had evidence of acquisition from a roommate, suggesting that cross-infection from a roommate was not a major route of spread of HGRE.

Attempts to eradicate methicillin-resistant Staphylococcus aureus from a long-term-care facility with the use of mupirocin ointment.

PURPOSE: To assess the impact of the use of mupirocin ointment on colonization, transmission, and infection with methicillin-resistant Staphylococcus aureus (MRSA) in a long-term-care facility. PATIENTS AND METHODS: All 321 residents of a Veterans Affairs long-term-care facility from June 1990 through June 1991 were studied for MRSA colonization and infection. MRSA-colonized patients received mupirocin ointment to nares in the first 7 months and to nares and wounds in the second 5 months. The effect of mupirocin use on MRSA colonization and infection was monitored. All S. aureus strains isolated were tested for the development of resistance to mupirocin. RESULTS: A total of 65 patients colonized with MRSA received mupirocin ointment. Mupirocin rapidly eliminated MRSA at the sites treated in most patients by the end of 1 week. Weekly maintenance mupirocin was not adequate to prevent recurrences--40% of patients had recurrence of MRSA. Overall, MRSA colonization in the facility, which was 22.7% +/- 1% prior to the use of mupirocin, did not change when mupirocin was used in nares only (22.2% +/- 2.1%), but did decrease to 11.5% +/- 1.8% when mupirocin was used in nares and wounds. Although colonization decreased, roommate-to-roommate transmission and MRSA infection rates, low to begin with, did not change when mupirocin was used. Mupirocin-resistant MRSA strains were isolated in 10.8% of patients. CONCLUSIONS: Mupirocin ointment is effective at decreasing colonization with MRSA. However, constant surveillance was required to identify patients colonized at admission or experiencing recurrence of MRSA during maintenance treatment. Long-term use of mupirocin selected for mupirocin-resistant MRSA strains. Mupirocin should be saved for use in outbreak situations, and not used over the long term in facilities with endemic MRSA colonization.

Methicillin-resistant Staphylococcus aureus: colonization and infection in a long-term care facility.

OBJECTIVE: To assess methicillin-resistant Staphylococcus aureus (MRSA) colonization, transmission, and infection over a 1-year period in a long-term care facility with endemic MRSA. DESIGN: Monthly surveillance for MRSA colonization of nares, perineum, rectum, and wounds. SETTING: Long-term care facility attached to an acute care Veterans Affairs medical center. PATIENTS: All 341 patients in the facility had monthly surveillance cultures for 1 year. OUTCOME MEASUREMENTS: Colonization and infection with MRSA. MAIN RESULTS: The monthly MRSA colonization rate was 23% +/- 1.0%; colonization occurred most commonly in the nares and wounds. Poor functional status was associated with MRSA colonization. Most patients (65%) never acquired MRSA; 25% of patients were already colonized at admission to the facility or at the start of the study, and only 10% of newly admitted patients acquired MRSA while in the facility. These latter patients acquired several different strains in a pattern of acquisition similar to that generally seen within the facility. In the course of 1 year, only nine patients who acquired MRSA had a roommate with the same phage type; no clustering was evident, and none of these patients developed infection. Nine other patients (3%) developed MRSA infection; five of these patients required hospitalization, but none died as a result of infection. CONCLUSIONS: In the long-term care facility in which our study took place, MRSA was endemic, and the infection rate was low. In such settings, the cost effectiveness of aggressive management of MRSA (widespread screening for MRSA and eradication with antimicrobial agents) needs to be assessed.