To assess the safety and efficacy of a chlorine dioxide water treatment system in controlling Legionella in a hospital water supply.

For 17 months following installation of the system, we performed regular water cultures throughout the building, assessed chlorine dioxide and chlorite levels, and monitored metal corrosion.

Sites that grew Legionella species decreased from 41% at baseline to 4% (P = .001). L. anisa was the only species recovered and it was found in samples of both hot and cold water. Levels of chlorine dioxide and chlorite were below Environmental Protection Agency (EPA) limits for these chemicals in potable water. Further, enhanced carbon filtration effectively removed the chemicals, even at chlorine dioxide levels of more than twice what was used to treat the water. After 9 months, corrosion of copper test strips exposed to the chlorine dioxide was not higher than that of control strips. During the evaluation period, there were no cases of nosocomial Legionella in the building with the system, whereas there was one case in another building.

Our results indicate that operation of a chlorine dioxide system effectively removed Legionella species from a hospital water supply. Furthermore, we found that the system was safe, as levels of chlorine dioxide and chlorite were below EPA limits. The system did not appear to cause increased corrosion of copper pipes. Our results indicate that chlorine dioxide may hold promise as a solution to the problem of Legionella contamination of hospital water supplies.

To determine influenza vaccination rates, vaccine effectiveness, and factors influencing vaccination decisions among house staff.

Cross-sectional survey.

All residents registered at the University of Toronto were surveyed after the 1999-2000 influenza season. Of the 1,159 questionnaires mailed, 670 (58%) could be evaluated.

Influenza-like illnesses were reported by 36% of house staff. The vaccination rate was 51% among respondents, being highest for community and occupational medicine and pediatric staff (77% and 75%) and lowest for psychiatry, surgery, and radiology staff (32%, 36%, and 36%). Vaccinees reported significantly fewer episodes of illness (42 vs 54 per 100 subjects; P = .03) and fewer days of illness (272 vs 374 per 100 subjects; P = .02); absenteeism was not different (63 vs 69 per 100 subjects; P = .69). Self-protection was the most common reason for vaccination. Vaccinees believed the vaccine was more effective than did non-vaccinees (P < .01). Non-vaccinees considered influenza-like symptoms the most important side effect of the vaccine. Busy schedules and inconvenience were the most common reasons for not getting vaccinated. Overall, 44% of house staff believed the influenza vaccine should be mandatory.

Influenza-like illness was common among house staff. They tended to work through their illnesses, potentially putting patients at risk. They were motivated mostly by self-protection and did report a benefit. Despite busy schedules and an unfounded fear of getting influenza symptoms from the vaccine, many thought the vaccine should be mandatory.

To determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) colonization in an outpatient population and to identify risk factors for MRSA colonization.

Surveillance cultures were performed during outpatient visits to identify S. aureus colonization. A case-control study was performed to identify risk factors for MRSA colonization.

Primary care internal medicine clinic. PATTENTS: Adults presenting for non-acute primary care (N = 494).

S. aureus was isolated from 122 (24.7%) of the patients for whom cultures were performed. Methicillin-susceptible S. aureus was isolated from 107 (21.7%) of the patients, whereas MRSA was isolated from 15 (3.0%) of the patients. All MRSA isolates were resistant to multiple non-beta-lactam antimicrobial agents. In multivariate analyses, MRSA colonization was independently associated with admission to a nursing home (adjusted odds ratio [OR], 103; 95% confidence interval [CI95], 7 to 999) or hospital in the previous year, although the association with hospital admission was observed only among those without chronic illness (adjusted OR 7.1; CI95, 1.3 to 38.1). In addition, MRSA colonization was associated with the presence of at least one underlying chronic illness, although this association was observed only among those who had not been hospitalized in the previous year (adjusted OR, 5.1; CI95, 1.2 to 21.9).

We found a low prevalence of MRSA colonization in an adult outpatient population. MRSA carriers most likely acquired the organism through contact with healthcare facilities rather than in the community. These data show that care must be taken when attributing MRSA colonization to the community if detected in outpatients or during the first 24 to 48 hours of hospitalization.

To investigate the relationship between hygienic measures reported for the prevention of hospital-acquired diarrhea and incidence rates of hospital-acquired diarrhea.

A survey of hospital-acquired diarrhea was conducted between January 1 and March 31, 1999. Multivariate analysis of reported measures of hygiene according to the observed incidence rates of hospital-acquired diarrhea was performed.

Thirty-one pediatric or neonatal wards located in hospitals in the southeast of France, selected as a convenience sample of wards volunteering to participate.

A total of 6,726 children younger than 5 years.

The overall incidence rate of hospital-acquired diarrhea was 3.6%. Rotavirus was responsible for 69% of the cases of hospital-acquired diarrhea. Among the hygienic measures reported by the wards for preventing hospital-acquired diarrhea were using a single room or cohorting (77.4%), washing hands (83.9%), wearing gowns (80.6%), and wearing disposable single-use gloves for diapering a patient (51.6%). By multivariate analysis, the variables statistically associated with a lower incidence of hospital-acquired diarrhea were restricting the patient's mobility outside his or her room, keeping the patient's door closed, and having fewer than 20 beds in the ward, with adjusted odds ratios of 0.34 (95% confidence interval [CL95], 0.18 to 0.65), 0.33 (CI95, 0.23 to 0.47), and 0.42 (CI95, 0.30 to 0.60), respectively.

Simple preventive measures can decrease the rate of hospital-acquired diarrhea in pediatric wards (Infect Control Hosp Epidemiol 2003;24:520-525)

To report the pooled results of seven prevalence surveys of hospital-acquired infections conducted between November 1996 and November 1999, and to use the data to predict the cumulative incidence of hospital-acquired infections in the same patient group.

The summary and modeling of data gathered from the routine surveillance of the point prevalence of hospital-acquired infections.

Auckland District Health Board Hospitals (Auckland DHBH), the largest publicly funded hospital group in New Zealand supplying secondary and tertiary services.

All inpatients.

Point-prevalence surveys were conducted including all patients in Auckland DHBH. Standard definitions of hospital-acquired infection were used. The data from the seven surveys were pooled and used in a modeling exercise to predict the cumulative incidence of hospital-acquired infection. An existing method for the conversion of prevalence to cumulative incidence was applied. Results are presented for all patients and stratified by clinical service and site of hospital-acquired infection.

The underlying patterns of hospital-acquired infection by site and service were stable during the seven time periods. The prevalence rate for all patients was 9.5%, with 553 patients identified with one or more hospital-acquired infections from a population of 5,819. The predicted cumulative incidence for all patients was 6.33% (95% confidence interval, 6.20% to 6.46%).

The prevalence and the predicted cumulative incidence are similar to rates reported in the international literature. The validity of the predicted cumulative incidence derived here is not known. If it were accurate, then the application of this method would represent a cost-effective alternative to incidence studies.

To assess the influence of nosocomial infection on length of stay in the intensive care unit (ICU) and to determine the relative effect of other factors on extra length of hospitalization associated with nosocomial infection.

Prospective cohort multicenter study in the context of the ENVIN-UCI project.

Medical or surgical ICUs of 49 different hospitals in Spain.

All consecutive patients (N = 6,593) admitted to ICUs of the participating hospitals who stayed for more than 24 hours during a 3-month period (from January 15 to April 15, 1996) were included. Length of ICU stay was compared between patients with and without nosocomial infections.

Uninfected patients (N = 5,868) had a median stay in the ICU of 3 days, whereas the median for infected patients (N = 725) was 17 days (P < .001). The median for infected patients with one episode of nosocomial infection was 13 days. The greatest length of stay (40 days) was among patients admitted to the ICU because of medical diseases, with an infection acquired before admission to the ICU, and with the largest number of nosocomial infection episodes. In extended stays, nosocomial infection was significantly associated with length of hospitalization (day 21; odds ratio, 22.38; 95% confidence interval, 16.6 to 30.4), whereas an effect of variables related to severity of illness on admission (Acute Physiology and Chronic Health Evaluation II score, urgent surgery, and infection prior to ICU admission) was not found.

The presence of nosocomial infection and the number of infection episodes were the variables with the strongest association with prolonged hospital stay among ICU patients.

CDC has estimated that 23% of Legionella infections are nosocomial. When a new hospital was being constructed and a substantial increase in transplantation was anticipated, an ultraviolet light apparatus was installed in the water main of the new building because 27% of water samples from taps in the old hospital contained Legionella. This study reports the rate of nosocomial Legionella infection and water contamination since opening the new hospital.

Charts of all patients with positive Legionella cultures, direct immunofluorescent antibody (DFA), or urine antigen between April 1989 and November 2001 were reviewed. Frequencies of DFAs and urine antigens were obtained from the laboratory.

None of the 930 cultures of hospital water have been positive since moving into the new building. Fifty-three (0.02%) of 219,521 patients had a positive Legionella test; 41 had pneumonia (40 community acquired). One definite L. pneumophila pneumonia confirmed by culture and DFA in August 1994 was nosocomial (0.0005%) by dates. This patient was transferred after prolonged hospitalization in another country, was transplanted 11 days after admission, and developed symptoms 5 days after liver transplant. However, tap water from the patient's room did not grow Legionella. Seventeen (2.5%) of 670 urine antigens were positive for Legionella (none nosocomial). Thirty-three (1.2%) of 2,671 DFAs were positive, including 7 patients (21%) without evidence of pneumonia and 6 (18%) who had an alternative diagnosis.

Ultraviolet light usage was associated with negative water cultures and lack of clearly documented nosocomial Legionella infection for 13 years at this hospital.

To determine the added costs of hygienic measures (barrier precautions, isolation, and decontamination) required for MRSA carriers in German hospitals and possible strategies for cost reduction.

On a septic surgical ward caring for 35% of all MRSA cases in a university hospital (1,182 beds), additional costs for personnel time and materials were calculated and medical charts of all MRSA cases admitted to the ward during 1 year were analyzed retrospectively. Twelve of the ward's 13 beds were located in rooms with at least 2 beds.

Four hundred ninety-eight MRSA carrier hospital-days (of 20 MRSA cases) could be assessed. All patients (80% men, 50% older than 74.5 years) had broken skin.

In 95% of the cases, microbiological findings suggested transmission of MRSA during the current or a previous stay on this ward. The study found total avoidable costs of approximately 142,794.01 euros in 1 year, averaging 371.95 euros for one MRSA patient hospital-day and 9,261.56 euros per MRSA case. The most expensive single measure was blocked beds in multibed rooms (305.75 euros/day), which accounted for 82% of the extra costs. Costs most likely were underestimated.

Daily additional case costs amounted to 96% of social security payments. Blocked beds in multibed rooms accounted for more than 80% of these excess costs. Isolation has been scientifically validated and is required by law in Germany. Building an adequate number of single-bed rooms should help prevent spread and would greatly lower the added costs of infection.

To determine the distribution of vancomycin-resistant enterococci (VRE) cases in our hospital and those from outside of our hospital from 1993 through 1998.

Weekly rectal surveillance was instituted whenever there were two or more cases present in the units. Cases were divided into acquired in our hospital, acquired outside of our hospital (VRE positive after and within 72 hours of admission, respectively), and indeterminate. Hospital cases were attributed to the originating ward or intensive care unit (ICU) if patients were noted to be positive within 72 hours of transfer.

From 1993 to 1998, the rate of VRE per 1,000 admissions increased threefold, from 3.2 to 9.8, for the hospital. VRE cases acquired outside of the hospital increased by approximately 5% per year (r = 0.87; P = .03). The rate of VRE per 1,000 admissions increased 1.7-fold in the ICUs and 3.6-fold in the wards. The ICUs had an average of 75.3 cases per year, with the number of new cases per year increasing by approximately 9 (r = 0.80; P = .028). In the wards, there were an average of 22.0 new cases per year, with a slight upward trend of 3 additional new cases per year (r = 0.69; P = .64). There was a highly significant increasing linear trend (P = .0007) for VRE colonization and infection.

Although VRE still predominate in the ICUs, cases originating from outside of our hospital and the wards are becoming more common. VRE colonization remained more frequent than infection.

Efficient methods are needed to monitor infections associated with long-term central venous catheters (CVCs) in both inpatient and outpatient settings. Automated medical records and claims data have been used for surveillance of these infections without evaluation of their accuracy or validity.

To determine the feasibility of using electronic records to identify CVC placement and design a system for identifying CVC-associated infections.

Retrospective cohort study at an HMO and two teaching hospitals in Boston, one adult (hospital A) and one pediatric (hospital B), between January 1991 and December 1997. Tunneled catheters, totally implanted catheters, and hemodialysis catheters were examined. Claims databases of both the HMO and the hospitals were searched for 10 CPT codes, 2 ICD-9 codes, and internal charge codes indicating CVC insertion. Lists were compared with each other and with medical records for correlation and accuracy.

All members of the HMO who had a CVC inserted at one of the two hospitals during the study period.

There was wide variation in the CVC insertions identified in each database. Although ICD-9 codes at each hospital and CPT/ICD-9 combinations at the HMO found similar total numbers of CVCs, there was little overlap between the individuals identified (62% for hospital A with HMO and 4% for hospital B).

Claims data from different sources do not identify the same CVC insertion procedures. Current administrative databases are not ready to be used for electronic surveillance of CVC-associated complications without extensive modification and validation.

To assess the quality of antibiotic prophylaxis for clean and clean-contaminated elective surgical procedures.

A cross-sectional, country-wide survey.

Thirty-six hospitals in 12 cities in Turkey.

Four hundred thirty-nine surgeons from 6 different specialties who performed selected procedures of interest.

A random sample of surgeons from different hospitals was selected. A standardized data collection form was used to record the type of procedure, the names, doses, timing of the first doses, and duration of antibiotics, important decisive factors, and problems in the management of prophylactic antibiotic use for surgical procedures.

Fifty-five percent of surgeons addressed completed the survey. For clean-contaminated procedures, 6% of surgeons did not use antibiotic prophylaxis, whereas 88% used more than a single dose. Inappropriate antibiotics were chosen for 32% of procedures. In 39% of procedures, the first dose of antibiotics was not administered during induction of anesthesia. Duration of prophylaxis was longer than 24 hours in 80% and longer than 48 hours in 46% of all procedures. Only 112 surgeons (26%) were using definitely appropriate prophylaxis in all ways. Multivariate analysis revealed that surgeons in university hospitals (OR, 2.353; CI95, 1.426–3.884; P = .001) and general surgeons (OR, 4.986; CI95, 2.890–8.604; P < .001) used antibiotic prophylaxis more appropriately. Patients not covered by health insurance (OR, 0.417; CI95, 0.225–0.772; P < .001) were associated with inappropriate prophylaxis.

Given the high frequency of antibiotics prescribed for surgical prophylaxis in Turkey, adherence to surgical prophylaxis guidelines is urgently needed.

To determine the efficacy of mupirocin ointment in reducing nasal colonization with mupirocin-susceptible, methicillin-resistant Staphylococcus aureus (MS MRSA) as well as mupirocin-resistant MRSA (MR MRSA).

Prospective evaluation in which patients colonized with MRSA were treated twice daily with 2% topical mupirocin ointment for 5 days.

James H. Quillen Veterans' Affairs Medical Center.

Forty hospitalized patients with two anterior nares cultures positive for MRSA within a 7-day period.

Treated patients had post-treatment cultures at day 3 and weeks 1,2, and 4. Isolates underwent mupirocin-susceptibility testing and DNA typing. MRSA clearance and type turnover were assessed for isolates that were mupirocin-susceptible, low-level (LL) MR MRSA and high-level (HL) MR MRSA.

Post-treatment nares cultures on day 3 were negative for 78.5%, 80%, and 27.7% of patients with MS MRSA, LL-MR MRSA, and HL-MR MRSA, respectively. Sustained culture negativity at 1 to 4 weeks was more common in the MS MRSA group (91%) than in the LL-MR MRSA group (25%) or the HL-MR MRSA group (25%). Positive post-treatment cultures usually showed the same DNA pattern relative to baseline. Plasmid curing of 18 HL-MR MRSA resulted in 15 MS MRSA and 3 LL-MR MRSA.

Mupirocin was effective in eradicating MS MRSA, but strains of MR MRSA often persisted after treatment. This appeared to reflect treatment failure rather than exogenous recolonization. MR MRSA is now more prevalent and it is appropriate to sample MRSA populations for mupirocin susceptibility prior to incorporating mupirocin into infection control programs.

To determine incidence rates of hospital-acquired infections and to develop preventive measures to reduce the risk of hospital-acquired infections.

Prospective surveillance for hospital-acquired infections was performed during a 5-year period in the wards housing general and vascular, thoracic, orthopedic, and general gynecologic and gynecologic-oncologic surgery of the University Medical Center Utrecht, the Netherlands. Data were collected from patients with and without infections, using criteria of the Centers for Disease Control and Prevention.

The infection control team recorded 648 hospital-acquired infections affecting 550 (14%) of 3,845 patients. The incidence density was 17.8 per 1,000 patient-days. Patients with hospital-acquired infections were hospitalized for 19.8 days versus 7.7 days for patients without hospital-acquired infections.

Prolongation of stay among patients with hospital-acquired infections may have resulted in 664 fewer admissions due to unavailable beds. Different specialties were associated with different infection rates at different sites, requiring a tailor-made approach. Interventions were recommended for respiratory tract infections in the thoracic surgery ward and for surgical-site infections in the orthopedic and gynecologic surgery wards.

Surveillance in four surgical wards showed that each had its own prominent infection, risk factors, and indications for specific recommendations. Because prospective surveillance requires extensive resources, we considered a modified approach based on a half-yearly point-prevalence survey of hospital-acquired infections in all wards of our hospital. Such surveillance can be extended with procedure-specific prospective surveillance when indicated.

To determine the in vitro efficacy of glucoprotamin for the disinfection of instruments.

Prospective observational study.

University women's hospital.

Instruments were immersed in saline solution after use, and glucoprotamin was added to a concentration of 1.5% before soaking for 60 minutes. Biocidal activity was determined by the difference in colony-forming units (CFU) on instruments before and after disinfection.

One hundred thirty-seven instruments were collected during 10 days and exposed to a 1.5% dilution of glucoprotamin without prior washing. Bioburden before disinfection ranged from 2 × 105 to 7.1 × 107 CFU per instrument. Average bacterial killing was 5.98 log10 CFU ± 0.48 under aerobic conditions and 6.75 log10 CFU ± 0.54 under anaerobic conditions, despite the presence of large amounts of proteins on instruments that were frequently bloody. No vegetative bacteria were isolated in any sample after disinfection.

This clinical study confirmed excellent in vitro efficacy of glucoprotamin without prior removal of proteins and debris.

Influenza vaccine receipt by healthcare workers (HCWs) is important because HCWs are at risk for occupational exposure to influenza and may act as vectors in the nosocomial transmission of influenza. HCWs were surveyed to determine whether belief in commonly held influenza vaccine misconceptions was associated with influenza vaccine acceptance.

Cross-sectional study.

A large urban teaching hospital.

A self-administered survey was used to assess nursing and physician staff influenza vaccine knowledge, current vaccination status, and potential reasons for vaccine declination.

Two hundred twelve of 215 surveys were completed. The overall influenza vaccination rate was 73%. Physician staff were significantly more likely to have been vaccinated compared with nursing staff (82% vs 62%, respectively; P = .0009). HCWs answering the 5 influenza vaccine basic knowledge questions correctly were significantly more likely to have been vaccinated than those responding incorrectly to any question (84% vs 64%, respectively; P = .002). This association was present in the nursing group where 80% of those answering the knowledge questions correctly were vaccinated, but only 49% of those answering incorrectly were vaccinated (P = .000005). However, in the physician group, there was no significant difference in the influenza vaccination rates between those answering correctly and those answering incorrectly (P = .459).

Belief in commonly held influenza vaccine misconceptions was significantly associated with influenza vaccine declination among nursing staff and may act as a barrier to greater rates of influenza vaccination. Reasons for influenza vaccine nonreceipt may differ between nursing and physician staff.

To model the economic costs of hospital-acquired infections (HAIs) in New Zealand, by type of HAI.

Monte Carlo simulation model.

Auckland District Health Board Hospitals (DHBH), the largest publicly funded hospital group in New Zealand supplying secondary and tertiary services. Costs are also estimated for predicted HAIs in admissions to all hospitals in New Zealand.

All adults admitted to general medical and general surgical services.

Data on the number of cases of HAI were combined with data on the estimated prolongation of hospital stay due to HAI to produce an estimate of the number of bed days attributable to HAI. A cost per bed day value was applied to provide an estimate of the economic cost. Costs were estimated for predicted infections of the urinary tract, surgical wounds, the lower and upper respiratory tracts, the bloodstream, and other sites, and for cases of multiple sites of infection. Sensitivity analyses were undertaken for input variables.

The estimated costs of predicted HAIs in medical and surgical admissions to Auckland DHBH were $10.12 (US $4.56) million and $8.64 (US $3.90) million, respectively. They were $51.35 (US $23.16) million and $85.26 (US $38.47) million, respectively, for medical and surgical admissions to all hospitals in New Zealand.

The method used produces results that are less precise than those of a specifically designed study using primary data collection, but has been applied at a lower cost. The estimated cost of HAIs is substantial, but only a proportion of infections can be avoided. Further work is required to identify the most cost-effective strategies for the prevention of HAI.