To determine the incidence, duration, and genetic diversity of colonization with vancomycin-resistant Enterococcus faecium (VREF).

Oncology unit of a 650-bed university hospital.

Surveillance perianal swab cultures were performed on admission and weekly. The molecular relatedness of VREF isolates was determined by pulsed-field gel electrophoresis and by the hybridization pattern of the vanA resistance determinant.

During 8 months of surveillance, the VREF colonization rate was 16.6 patients per 1,000 patient-hospital days, which was 10.6 times greater than the VREF infection rate. Eighty-six patients with VREF colonization were identified. Colonization persisted for at least 7 weeks in the majority of patients. Of 36 colonized patients discharged from the hospital and then readmitted, an average of 2½ weeks later, 22 (61%) patients still were colonized with VREF. Of the 14 patients who were VREF-negative at readmission, only three patients remained culture-negative throughout hospitalizations. PFGE demonstrated that colonization with the same VREF isolate may persist for at least 1 year, and patients may be colonized with more than one strain of VREF.

VREF colonization is at least 10-fold more prevalent than infection among oncology patients. Colonization often persists throughout lengthy hospitalizations and may continue for long periods following hospitalization.

To investigate the cause of increasing rates of nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infection at a university hospital.

Review of data collected by prospective hospitalwide surveillance regarding rates of nosocomial MRSA colonization and infection.

A 700-bed university hospital providing primary and tertiary care.

Patients admitted to the hospital between 1986 and 1993 who were found to be infected or colonized with MRSA.

Rates of MRSA infection and colonization.

MRSA infection or colonization was identified in 399 patients (0.18%) admitted during the 8-year study. There was no correlation between the annual rates of MRSA and methicillin-sensitive Staphylococcus aureus (MSSA) infections (P=.66). The frequency of both nosocomial and non-nosocomial cases increased significantly over the last 4 years of the study (P<.001 for trend). The ratio of patients who had acquired MRSA nosocomially to those admitted who already were infected or colonized decreased significantly during the study period (P=.002 for trend). There was a significant increase in the frequency of patients with MRSA being transferred from nursing homes and other chronic care facilities (P=.011). A cost-benefit analysis suggested that surveillance cultures of patients transferred from other healthcare facilities would save between $20,062 and $462,067 and prevent from 8 to 41 nosocomial infections.

An increase in the incidence of nosocomial MRSA infection was associated with an increased frequency of transfer of colonized patients from nursing homes and other hospitals. The lack of correlation between rates of MRSA and MSSA infections suggested that MRSA infections significantly increased the overall rate of staphylococcal infection. Screening cultures of transfer patients from facilities with a high prevalence of MRSA may offer significant benefit by preventing nosocomial infections and reducing patient days spent in isolation.

To compare the accuracy of infection control practitioners' (ICPs') classifications of operative site infection in Florida Consortium for Infection Control (FCIC) hospitals, in two time periods, 1990 to 1991 and 1991 to 1992, and to estimate the effect of duration of surveillance experience on that accuracy.

Medical record reviewers examined records of all patients classified by an ICP as infected, to distinguish false-positives from true infections based on evidence of standard infection criteria and the ICP's contemporaneous clinical observations. Reviewers also examined a random sample of 100 records from patients classified as noninfected for evidence of undetected infections (false-negatives). These observations permitted estimates of the sensitivity and specificity of each ICP's classification of infection status.

Fourteen FCIC communit:y hospitals at which performance of 16 ICPs was monitored.

There was a strong linear trend relating increasing sensitivity to numbers of years of ICP surveillance experience (P<.001). For ICPs with <4 years of experience, satisfactory sensitivity (≥80%) was reached in only one of 10 ICP-years of observation. For ICPs with ≥4 years' experience, satisfactory sensitivity was achieved for 14 of 18 person-years (P=.001). Estimated specificity was 97% to 100% for all ICP-years observed.

ICPs with <4 years of surveillance experience in FCIC community hospitals rarely achieved a satisfactory sensitivity estimate, whereas ICPs with≥4 years' experience generally did. Monitoring ICP surveillance accuracy through retrospective medical record audits offers an objective approach to evaluating ICP performance and to interpreting infection rates at different hospitals.

To study the epidemiology and preventability of blood contact with skin and mucous membranes during surgical procedures.

Observers present at 1,382 surgical procedures recorded information about the procedure, the personnel present, and the contacts that occurred.

Four US teaching hospitals during 1990.

Operating room personnel in five surgical specialties.

Numbers and circumstances of contact between the patient's blood (or other infective fluids) and surgical personnel's mucous membranes (mucous membrane contacts) or skin (skin contacts, excluding percutaneous injuries).

A total of 1,069 skin (including 620 hand, 258 body, and 172 face) and 32 mucous membrane (all affecting eyes) contacts were observed. Surgeons sustained most contacts (19% had ≥1 skin contact and 0.5% had ≥1 mucous membrane-eye contact). Hand contacts were 72% lower among surgeons who double gloved, and face contacts were prevented reliably by face shields. Mucous membrane-eye contacts were significantly less frequent in surgeons wearing eyeglasses and were absent in surgeons wearing goggles or face shields. Among surgeons, risk factors for skin contact depended on the area of contact: hand contacts were associated most closely with procedure duration (adjusted odds ratio [OR], 9.4; ≥4 versus <1 hour); body contacts (arms, legs, and torso) with estimated blood losses (adjusted OR, 8.4; ≥1,000 versus <100 mL); and face contacts, with orthopedic service (adjusted OR, 7.5 compared with general surgery).

Skin and mucous membrane contacts are preventable by appropriate barrier precautions, yet occur commonly during surgery. Surgeons who perform procedures similar to those included in this study should strongly consider double gloving, changing gloves routinely during surgery, or both.

To investigate an apparent excess of operative site infections (OSI) reported according to doctor's diagnosis (presumptive OSI) by applying objective criteria for classification (documented OSI). To examine potential consequences of habitual overdiagnosis of OSI.

A case-control design was used to examine the clinical course of 18 case patients (12 presumptive OSI, six documented OSI) and 18 matched controls. Comparisons also were made between presumptive and documented OSI patients.

A nonteaching community hospital.

Thirty-six patients having laminectomies done by the same surgeon.

Implementation of objective criteria for diagnosis of confirmed OSI and reclassification of presumptive OSI patients.

Postoperatively, the frequency of specific adverse events within the operative site (including post-operative hematoma or bleeding; wound necrosis, dehiscence, or sinus tract; and dural tear) was 83% for documented OSI patients, contrasted with 16.7% for presumptive OSI patients (P<.01) and controls (P=.007). Median days of inpatient stay were 27 for documented OSI, contrasted with 9.5 for presumptive OSI (P=.01) and 7 for controls (P<.001).

Documented OSI patients were found to have significantly more adverse findings and longer lengths of stay than presumptive OSI patients or controls. The similarity of findings for presumptive OSI patients and controls suggests that the apparent excess frequency of OSI was caused by incorrect diagnosis. Whereas doctor's diagnosis may be useful as an initial screen for OSI, use of objective criteria for confirming OSI may avert the consequences of overdiagnosis, including excessive length of stay and unnecessary therapy, which lead to elevated healthcare costs and threaten a physician's practice.

To evaluate the clonality of methicillin-resistant Staphylococcus aureus (MRSA) strains among hospitalized patients.

University-affiliated, 465-bed tertiary-care teaching hospital with adjacent cancer clinic in Hamilton, Ontario, Canada.

Thirty-five colonized and 30 infected patients from January 2, 1992, through August 31, 1993, were investigated retrospectively. Analysis by restriction fragment-length polymorphisms of ribosomal RNA genes (ie, ribotyping) of 103 nosocomial isolates of MRSA from these 65 patients and of 25 selected unrelated strains was completed. Ribotyping results were compared with the phage typing data obtained prospectively during the course of prospective MRSA surveillance.

HindIII ribotyping was more discriminating than phage typing when epidemiologically unrelated strains were differentiated by these methods (19 different ribotypes versus 14 phage types; P< .005). Two early index cases were identified. Isolates from the index cases were two different strains, identified by ribotyping analysis as ribotype A (clonal group 1) and ribotype B (clonal group 2), respectively. These two ribotypes were not found when typing the unrelated control strains. Thirty-six colonized and infected patients (55%) had clonal group 1 isolates, and 20 (31%) had clonal group 2 isolates. These two clones emerged in the hospital in January and February 1992 and dominated the entire investigated period. There also were six patients with an additional clonal group (group 4) that emerged and disappeared in the second quarter of 1993.

This study highlights the utility of ribotyping in investigating nosocomial MRSA. Three MRSA clones caused nosocomial colonization or infection in patients at this hospital. Two of these MRSA clones, once introduced, were maintained among our patients throughout the study period.