To evaluate a computer-assisted point-prevalence survey (CAPPS) for hospital-acquired infections (HAIs).

Validation cohort.

A 754-bed teaching hospital in the Netherlands.

For the internal validation of a CAPPS for HAIs, 2,526 patients were included. All patient records were retrospectively reviewed in depth by 2 infection control practitioners (ICPs) to determine which patients had suffered an HAI. Preventie van Ziekenhuisinfecties door Surveillance (PREZIES) criteria were used. Following this internal validation, 13 consecutive CAPPS were performed in a prospective study from January to March 2013 to determine weekly, monthly, and quarterly HAI point prevalence. Finally, a CAPPS was externally validated by PREZIES (Rijksinstituut voor Volksgezondheid en Milieu [RIVM], Bilthoven, Netherlands). In all evaluations, discrepancies were resolved by consensus.

In our series of CAPPS, 83% of the patients were automatically excluded from detailed review by the ICP. The sensitivity of the method was 91%. The time spent per hospital-wide CAPPS was ~3 hours. External validation showed a negative predictive value of 99.1% for CAPPS.

CAPPS proved to be a sensitive, accurate, and efficient method to determine serial weekly point-prevalence HAI rates in our hospital.

Infect Control Hosp Epidemiol 2016;1–6

TO evaluate the effectiveness of a rigorous search and destroy policy for controlling methicillin-resistant Staphylococcus aureus (MRSA) infection or colonization.

Hospital-based observational follow-up study.

Erasmus University Medical Center Rotterdam, a 1,200-bed tertiary care center in Rotterdam, the Netherlands.

Outbreak control was accomplished by the use of active surveillance cultures for persons at risk, by the preemptive isolation of patients at risk, and by the strict isolation of known MRSA carriers and the eradication of MRSA carriage. For unexpected cases of MRSA colonization or infection, patients placed in strict isolation or contact isolation and healthcare workers (HCWs) were screened. We collected data from 2000–2004.

During the 5-year study period, 51,907 MRSA screening cultures were performed for 21,598 persons at risk (8,403 patients and 13,195 HCWs). By screening, it was determined that 123 (1.5%) of 8,403 patients and 31 (0.2%) of 13,195 HCWs were MRSA carriers. From the performance of clinical cultures, it was determined that 54 additional patients were MRSA carriers, resulting in a total of 177 patients carrying MRSA. Of the 177 patients carrying MRSA, 144 (81%) were primary patients, and 33 (19%) secondary Patients. The average number of nosocomial transmissions was 6.7 per year. The cumulative incidence of MRSA colonization among this group of patients was 0.10 cases per 100 admissions. Of 156 cases of MRSA colonization, 44 (28%) were acquired in a foreign healthcare institution, and 45 (29%) were acquired in other Dutch hospitals, 22 (47%) of which were acquired in a single hospital in our region. There were 16 cases (10%) that occurred in a nursing home and another 16 cases (10%) that fulfilled our definition of community-acquired MRSA colonization; there were 4 cases (3%) categorized as “other” and 31 cases (20%) for which the source of MRSA acquisition remained unknown. The basic reproduction rate was 10-fold less for patients isolated on admission, compared with those who were not. During the 5-year study period, 5 episodes of MRSA bacteremia occurred in which 4 patients died, an incidence rate of 0.28 cases of infection per 100,000 patient-days per year.

Our results show that, during a rigorous search and destroy policy, a low incidence of MRSA in our medical center was continuously observed and that this policy most likely contributed to a very low nosocomial transmission rate.

Nasal carriage of Staphylococcus aureus is an important risk factor for S. aureus infection and a reservoir for methicillin-resistant S. aureus. We investigated whether nose picking was among the determinants of S. aureus nasal carriage.

The study cohort comprised 238 patients who visited the ear, nose, and throat (ENT) disease outpatient clinic of a tertiary care hospital and did not have a nose-specific complaint (defined as ENT patients) and 86 healthy hospital employees (including medical students and laboratory personnel).

All participants completed a questionnaire on behavior regarding the nose and were screened for S. aureus nasal carriage; only ENT patients underwent nasal examination by an ear, nose, and throat physician for clinical signs of nose picking.

Among ENT patients, nose pickers were significantly more likely than non–nose pickers to carry S. aureus (37 [53.6%] of 69 vs 60 [35.5%] of 169 patients; relative risk, 1.51 [95% confidence interval, 1.03-2.19]). Among healthy volunteers, there was a statistically significant positive correlation between the self-perceived frequency of nose picking and both the frequency of positive culture results (R = 0.31; P = .004) and the load of S. aureus present in the nose (R = 0.32; P = .003).

Nose picking is associated with S. aureus nasal carriage. The role of nose picking in nasal carriage may well be causal in certain cases. Overcoming the habit of nose picking may aid S. aureus decolonization strategies.

To determine the prevalence and determinants of fecal carriage of vancomycin-resistant enterococci (VRE) in intensive care unit (ICU), hematology-oncology, and hemodialysis patients in The Netherlands.

Descriptive, multicenter study, with yearly 1-week point-prevalence assessments between 1995 and 1998.

All patients hospitalized on the testing days in ICUs and hematology-oncology wards in nine hospitals in The Netherlands were included.

Rectal swabs obtained from 1,112 patients were screened for enterococci in a selective broth and subcultured on selective media with and without 6 mg/L vancomycin. Resistance genotypes were determined by polymerase chain reaction. Further characterization of VRE strains was done by pulsed-field gel electrophoresis (PFGE). We studied possible determinants of VRE colonization with a logistic regression analysis model. Determinants analyzed included gender, age, and log-transformed length of prior hospital stay.

The results showed that 614 (55%) of 1,112 patients were colonized with vancomycin-sensitive enterococci, and 15 (1.4%) of 1,112 carried VRE. No increase in VRE colonization was observed from 1995 to 1998. Eleven strains were identified as Enterococcus faecium and four as Enterococcus faecalis. All E faecium and one E faecalis carried the vanA gene; the other E faecalis strains harbored the vanB gene. PFGE revealed that three vanB VRE isolated from patients hospitalized in one single ICU were related, suggesting nosocomial transmission. Though higher age seemed associated with VRE colonization, exclusion of patients with the nosocomial strain from the regression analysis decreased this relation to nonsignificant. Duration of hospital stay was not associated with VRE colonization.

VRE colonization in Dutch hospitals is an infrequent phenomenon. Although nosocomial spread occurs, most observed cases were unrelated, which suggests the possibility of VRE acquisition from outside the hospital. Prolonged hospital stay, age, and gender proved unrelated to VRE colonization.

To assess the cost-effectiveness of perioperative intranasal application of mupirocin calcium ointment in cardiothoracic surgery.

Cost-effectiveness analysis based on results of an intervention study with historical controls.

University Hospital Rotterdam, a tertiary referral center for cardiac and pulmonary surgery.

Consecutive patients undergoing cardiothoracic surgery between August 1, 1989, and February 1, 1991 (control group, n=928), and between March 1, 1991, and August 1, 1992 (intervention group, n=868).

Perioperative nasal application of mupirocin calcium ointment started on the day before surgery, continued for 5 days, twice daily.

Postoperative costs were increased significantly in patients with a surgical-site infection (SSI), compared with uninfected patients (P<.001). Mean SSI-attributable costs were estimated at $16,878 (95% confidence interval, $15,575-$18,181). The incidence of SSIs was 7.3% in the control group and 2.8% in the intervention group, mupirocin effectiveness being 62%. The costs of mupirocin were $11 per patient. Thus, the savings per SSI prevented were $16,633. To validate this comparative estimate of SSI-attributable costs, a noncomparative analysis of the postoperative length of stay (POLS) was performed, according to the Appropriateness Evaluation Protocol. Approximately 50% of the comparative SSI-attributable POLS were judged SSI-attributable in the noncomparative analysis. Sensitivity analyses, testing for the robustness of our conclusions, indicated that the presented model is rather insensitive to variations in the incidence of SSIs and for the effectiveness and costs of mupirocin. SSI-attributable costs were shown to be the only variable with substantial effect on the cost-effectiveness ratio. Perioperative mupirocin would result in net costs instead of savings only if SSI-attributable costs were less than $245.

SSIs in patients undergoing cardiothoracic surgery are associated with a substantial increase in postoperative costs. Provided that perioperative mupirocin reduces the SSI rate, this measure will be highly cost-effective in most centers providing cardiothoracic surgical services.

To study the efficacy of mupirocin for the elimination of nasal carriage of Staphylococcus aureus in hemodialysis patients.

The efficacy of mupirocin was studied in a prospectively followed cohort. The effect of this intervention on the rate of S aureus bacteremia was evaluated using a historic control group.

Patients on the hemodialysis unit of the University Hospital Rotterdam, a tertiary referral center.

The study group consisted of consecutive patients on hemodialysis from February 1, 1992, until November 1, 1993. They were screened by taking nasal cultures monthly during their time on hemodialysis. If S aureus was isolated, treatment with mupirocin nasal ointment was initiated. The control group consisted of patients treated on the same hemodialysis unit from January 1, 1990, until January 1, 1992.

The study group consisted of 226 patients, of whom 172 were evaluated to determine the efficacy of mupirocin. Sixty-seven (39%) were identified as nasal carriers. Following the initial treatment, 66 nasal cultures (98.5%) became negative. After 3 months and 6 months, respectively, 63 (94%) and 61 (91%) of the treated carriers had negative cultures. The rate of bacteremia (defined as the number of episodes of 5 aureus bacteremia per patient-year on hemodialysis) was significantly lower among the 226 patients in the study group (0.04 per patient-year) than among the 273 patients in the control group (0.25 per patient year; P <.001). Development of resistance and adverse effects were not observed.

Mupirocin nasal ointment effectively eliminates nasal carriage of 5 aureus in patients on hemodialysis. This was associated with a significant reduction of the incidence of 5 aureus bacteremia, as compared to historic controls.

To test the hypothesis that perioperative elimination of nasal carriage of Staphylococcus aureus using mupirocin nasal ointment reduces the surgical-site infection (SSI) rate in cardiothoracic surgery.

Unblinded intervention trial with historical controls.

A university hospital, tertiary referral center for cardiothoracic surgery.

Consecutive patients undergoing cardiothoracic surgery between August 1, 1989, and February 1, 1991 (historical control group), and between March 1, 1991, and August 1, 1992 (intervention group).

The historical control group consisted of 928 patients and the intervention group of 868, of whom 752 actually were treated. The 116 patients who were unintentionally not treated were considered as a concurrent control group. In the intention-to-treat analysis, a significant reduction in SSI rate was observed after the intervention (historical-control group 7.3% and intervention group 2.8%; P<.0001). The SSI rate in the concurrent control group was significantly higher than in the treated group (7.8% and 2.0%, respectively; P=.0023). Resistance of S aureus to mupirocin was not observed.

The results of this study indicate that perioperative elimination of nasal carriage using mupirocin nasal ointment significantly reduces the SSI rate in cardiothoracic surgery patients and warrants a prospective, randomized, placebo-controlled efficacy trial. This preventive measure may be beneficial in other categories of surgical patients as well.

To determine persistence of coagulase-negative staphylococci (CNS) on a hematology-oncology ward and to determine the value of phenotypic and genotypic procedures for establishing clonality among CNS isolates.

Strains of CNS isolated from bacteremic patients (n=139) were typed by biochemical reactivity, antibiotic susceptibility, DNA macrorestriction analysis by pulsed-field gel electrophoresis (PFGE), and arbitrary primed polymerase chain reaction (AP PCR). Coagulase-negative staphylococci were subgrouped in a random collection (n=20) used for the evaluation of the typing procedures and a collection of 119 CNS isolates from hematologic patients displaying multiple bacteremic episodes.

Analysis of the reference collection demonstrated the usefulness of the DNA typing procedures, indicating that AP PCR and PFGE can be used for epidemiologic typing of CNS in a concordant fashion. Certain strains appeared to be permanent colonizers of the hematology ward or ward-related personnel. In individual patients, persistent colonization by a single type was demonstrated. However, a number of patients also experienced bacteremic episodes caused by CNS belonging to different types.

We conclude that monitoring of CNS infections on a hematology ward by various genotypic techniques provides insight into nosocomial epidemiology and elucidates the complexity of the infections taking place. DNA typing is preferred over phenotypic procedures and can identify persistent CNS strains in a given location.