Carole Brennen

A Prospective Study of Nosocomial Infections in a Chronic Care Facility

To elucidate the epidemiology of nosocomial infections occurring in nursing homes and chronic care facilities, the authors undertook a prospective study of patients requiring two different levels of nursing care. The overall rate of infection was higher on the intermediate care ward than on the nursing home ward (1.35 versus 0.67 infections/100 patient care days). Pneumonias and symptomatic urinary tract infections accounted for 49 per cent of all infections. Eight of ten cases of pneumonia occurring on the nursing home ward were diagnosed in the winter months, and no case was diagnosed in the summer months. Resistance to gentamicin, tobramycin, ampicillin, and trimethoprim—sulfa was common among organisms causing symptomatic urinary tract infections.

Isolation of Staphylococcus aureus from the Urinary Tract: Association of Isolation with Symptomatic Urinary Tract Infection and Subsequent Staphylococcal Bacteremia

BACKGROUND Staphylococcus aureus is frequently isolated from urine samples obtained from long-term care patients. The significance of staphylococcal bacteriuria is uncertain. We hypothesized that S. aureus is a urinary pathogen and that colonized urine could be a source of future staphylococcal infection. METHODS We performed a cohort study of 102 patients at a long-term care Veterans Affairs facility for whom S. aureus had been isolated from clinical urine culture. Patients were observed via urine and nasal cultures that were performed every 2 months. We determined the occurrence of (1) symptomatic urinary tract infection concurrent with isolation of S. aureus (by predetermined criteria), (2) staphylococcal bacteremia concomitant with isolation of S. aureus from urine, and (3) subsequent episodes of staphylococcal infection. RESULTS Of 102 patients, 82% had undergone recent urinary catheterization. Thirty-three percent of patients had symptomatic urinary tract infection at the time of initial isolation of S. aureus, and 13% were bacteremic. Eight-six percent of the initial urine isolates were methicillin-resistant S. aureus. Seventy-one patients had follow-up culture data; 58% of cultures were positive for S. aureus at > or =2 months (median duration of staphylococcal bacteriuria, 4.3 months). Sixteen patients had subsequent staphylococcal infections, occurring up to 12 months after initial isolation of S. aureus; 8 late-onset infections were bacteremic. In 5 of 8 patients, the late blood isolate was found to have matched the initial urine isolate by pulsed-field gel electrophoresis typing. CONCLUSIONS S. aureus is a cause of urinary tract infection among patients with urinary tract catheterization. The majority of isolates are methicillin-resistant S. aureus. S. aureus bacteriuria can lead to subsequent invasive infection. The efficacy of antistaphylococcal therapy in preventing late-onset staphylococcal infection in patients with persistent staphylococcal bacteriuria should be tested in controlled trials.

Vancomycin-resistant Enterococcus faecium in a long-term care facility

OBJECTIVE: To describe the epidemiology and natural history of colonization with vancomycin‐resistant Enterococcus faecium (VREF) in a long‐term care facility.

Infection with Methicillin-Resistant Staphylococcus aureus Among Hospital Employees

OBJECTIVE To describe the spectrum of clinical infection caused by methicillin-resistant Staphylococcus aureus (MRSA) in healthcare workers. DESIGN Case series. SETTING Two Veterans Affairs hospitals in which methicillin-resistant S aureus (MRSA) is endemic. PATIENTS Five employees presenting to employee health or infectious disease clinic. RESULTS All employees had had direct exposure to patients colonized with MRSA. Employee infections included cellulitis, impetigo, folliculitis, paronychia, and conjunctivitis. MRSA was isolated from all clinically infected sites and from the anterior nares of two employees. Three employees received a variety of ineffective oral antimicrobials before MRSA was recognized as the causative agent. All infections responded to appropriate therapy. CONCLUSIONS Employees of hospitals with endemic MRSA may acquire MRSA infection. Presentation in our employees was that of relatively uncomplicated soft tissue infection, but several employees received inappropriate therapy before bacteriologic diagnosis. We recommend that culture and susceptibility testing be obtained prior to institution of therapy when hospital employees present with soft tissue infection.

Occult Endemic Tuberculosis in a Chronic Care Facility

During the course of a tuberculosis skin testing program at a chronic care Veterans Administration Medical Center, we uncovered evidence of occult transmission of endemic tuberculosis. Skin test conversion of eight patients (one of whom had unsuspected progressive primary tuberculosis) and two employees was ultimately traced to a patient in whom tuberculosis was first diagnosed at autopsy three years earlier. Identification of employee skin test conversions was a key factor in recognizing and terminating disease transmission. Throughout the institution, 33% of patients were tuberculin-positive; 10.8% demonstrated the booster phenomenon after initial negative skin tests. Prevalence of tuberculin positivity among employees was 28%. Twelve percent of initially tuberculin-negative employees converted during employment. Our experience documents the value of tuberculin testing of both patients and staff in a chronic care environment, and the necessity of vigorous investigation of skin test conversions.

Choosing appropriate criteria for tuberculin positivity and conversion in a long-term care facility.

OBJECTIVES The Centers for Disease Control and Prevention has issued new criteria for conversion of the tuberculin skin test; in persons over 35 years of age, an increase in induration of at least 15 mm is considered indicative of new tuberculous infection. We reviewed our experience in a tuberculosis control program in a long-term care facility to assess the applicability of the new criteria to our patient population. DESIGN Retrospective review of seven years of tuberculosis control records and outbreak investigation. SETTING Long-term care Veterans Affairs hospital. PATIENTS All patients in the facility between 1985 and June 1992 who received routine admission and annual tuberculin skin testing or who were evaluated for possible exposure to active tuberculosis. A total of 2,342 skin tests were performed. RESULTS Mean increase in skin test diameter in patients with at least two prior negative tests and known exposure to active tuberculosis was 13.9 +/- 4.7 mm. Frequency distribution histograms of skin test sizes of initial tuberculin testing in the entire population indicated 10 mm induration as a reasonable criterion for initial positivity. CONCLUSIONS In our long-term care population, an increase in skin test induration of 10 mm may indicate new tuberculous infection. Criteria for skin test conversion derived from ambulatory populations in other geographic areas may not apply in all situations. Prevalence of infection with Mycobacterium tuberculosis and prevalence of skin test reactivity due to nontuberculous mycobacteria are likely to influence the predictive value of criteria for tuberculin conversion in a given population.