A performance improvement task force of Rhode Island infection control professionals was created to develop an epidemiologic model of statewide consistent infection control practices that could reduce the spread of methicillin-resistant Staphylococcus aureus (MRSA).

This model encompasses screening protocols, isolation techniques, methods of cohorting positive patients, decolonization issues, postexposure follow-up, microbiology procedures, and standardized surveillance methodologies. These “best practice guidelines” include three categories of recommendations that define priority levels based on the availability of scientific data.

From 1995 through 2000, several Rhode Island hospitals experienced a fivefold increase in nosocomial acquisition of MRSA.

Rhode Island infection control professionals are a highly interactive group in the unique position of sharing patients and ultimately experiencing similar trends and problems.

The task force collaborated on developing the best hospital infection control practices to prevent and control the spread of MRSA in Rhode Island.

The task force met with local infectious disease physicians and representatives from the Rhode Island Department of Health, the Hospital Association of Rhode Island, and Rhode Island Quality Improvement Partners. Discussions identified numerous and diverse MRSA control practices, issues of consensus, and approaches to resolving controversial methods of reducing the spread of MRSA The guidelines regarding the best hospital practices for controlling MRSA were finalized 8 months later.

These guidelines were distributed to all chief executive officers of Rhode Island hospitals by the Rhode Island Department of Health in December 2001. They were issued separate and apart from any regulations, with the intent that hospitals will adopt them as best hospital practices in an attempt to control MRSA.

To determine whether patients who were colonized or infected with methicillin-resistant Staphylococcus aureus (MRSA) persistently carried the same strain and to identify the extent of strain variation within a population of patients.

Molecular typing by pulsed-field gel electrophoresis (PFGE) of stored MRSA isolates.

A Veterans Administration Medical Center with 288 hospital, 45 intermediate-care, and 75 extended-care beds.

Between January 1991 and March 1993, 91 patients had MRSA identified in routine cultures. One hundred isolates from 57 patients (63%) were available for typing.

Before 1988, only occasional MRSA isolates were identified. By 1993, 50% of S. aureus isolates from unique patients were resistant to methicillin. PFGE identified 7 MRSA strains, 3 of which were identified in specimens from 1 patient each. The most common strains were SD4 (20 patients), SD1 (12 patients), SD2 (12 patients), and SD5a (5 patients). Twenty patients had 2 or more isolates obtained at least 1 week apart (mean, 30.7 weeks; range, 1 to 102 weeks). Of these patients, 12 were colonized or infected with only one strain (mean time observed, 25.1 weeks; range, 1 to 82 weeks). Eight patients had at least 2 different strains (mean time observed, 39 weeks; range, 2 to 102 weeks).

Numerous MRSA strains circulated in tiiis endemic setting; 40% of patients observed over time were colonized or infected witii more than one strain. Molecular typing was an essential tool for evaluating the epidemiology of MRSA in this setting.

To determine the incidence of nosocomial infections (NIs) and fever of unknown origin among adult hematology–oncology patients.

Prospective surveillance study.

The 18-bed hematology–oncology unit at the University Hospital Bonn, Bonn, Germany.

All hematology–oncology patients admitted during a total of 8 months in 1998 and 1999.

Standardized surveillance system based on the Centers for Disease Control and Prevention's National Nosocomial Infections Surveillance system. Rates of NI and fever of unknown origin were calculated for patient-days and patient-days at risk (ie, days with neutropenia of < 500/mm3 or leukopenia of < 1,000/mm3).

Of 116 patients hospitalized for a total of 4,002 days (172 admissions; mean length of stay, 25.2 days), 32 (27.6%) had a total of 44 documented NIs (19 bloodstream infections, 15 pneumonias, 7 urinary tract infections, and 3 others). In addition, 33 fevers of unknown origin were documented in 28 patients. No patient had thrush while receiving antifungal prophylaxis. The overall rates for NI and fever of unknown origin were 11.0 and 8.2 per 1,000 patient-days (25.3 and 15.4 per 1,000 patient-days at risk), respectively. The risks for NI and fever of unknown origin were significantly higher during neutropenic days, with 34 (77.3%) of the 44 NIs and 22 (66.7%) of the 33 fevers of unknown origin occurring during 1,345 patient-days at risk.

Prospective surveillance for NIs on hematology–oncology units should include fever of unknown origin as the single most common and clinically important entity. For a meaningful comparison of surveillance data for hematology–oncology patients, the reported infection rates should include rates based on days with neutropenia, for which days with leukopenia could serve as a surrogate marker under routine conditions.

To obtain information about current reprocessing practices and to obtain samples from the biopsy channel to quantitate soil levels and bioburden in patient-ready flexible duodenoscopes used for endoscopic retrograde choliangiopancreatography (ERCP).

Participating centers were sent a questionnaire and a kit for on-site collection of samples from the biopsy channel of the duodenoscope.

Thirty-seven hospitals from across Canada participated. The only criterion was that they currently used and reprocessed flexible duodenoscopes for ERCP procedures.

The questionnaire obtained information on reprocessing practices. The kit included a detailed instruction booklet outlining sample collection and all of the tubes, sterile water, and brushes needed for it. Samples were collected on-site from all ERCP scopes in each center on Monday morning and shipped by overnight courier on ice to the research center. Each sample was assayed by routine microbiologic methods for total viable count and protein, blood, carbohydrate, and endotoxin levels.

Microbial overgrowth was present in 7% of 119 scope samples. Cleaning appeared to be reasonably well done in most of the centers, and 43% of the centers were in total compliance with basic national guidelines. The data from the scope samples indicated that there was significantly greater buildup of protein, carbohydrate, and endotoxin associated with ERCP scopes from centers using glutaraldehyde, compared with those using peracetic acid. Carbohydrate was the soil component detected most frequently and in the highest concentration in scope channels.

Although cleaning was generally well done, areas for improvement included ensuring the availability of written reprocessing protocols, immersion of scopes during manual cleaning, use of adequate fluid volume for rinsing, adequate drying of scopes prior to storage, and the separation of ERCP valves from scopes during storage.

To determine the epidemiology and relatedness of Clostridium difficile isolates in two geographically separated hospitals in a large metropolitan area, each with unique patients and personnel.

Observational descriptive molecular epidemiology of clinical C. difficile isolates.

Two tertiary-care hospitals in Chicago.

Consecutive C. difficile isolates from the clinical laboratory of a Veterans Affairs hospital during a 13-month period were typed by restriction endonuclease analysis (REA). During an overlapping 3-month period, stool specimens that tested positive for C. difficile toxin from patients at a nearby county hospital were cultured and the recovered isolates typed by the same method.

Nineteen (68%) of 28 nosocomial isolates at the smaller, Veterans Affairs hospital belonged to REA group K. Within this group of closely related strains, 9 distinct REA types were recognized. Twenty-one (72%) of 29 nosocomial isolates at the larger, county hospital also belonged to group K. However, the predominant REA types within group K differed markedly at each institution.

These findings demonstrate a high degree of similarity among nosocomial C. difficile strains from different hospitals in the same city and suggest the possibility of an extended outbreak of a prototype group K strain with subsequent genetic drift at the two different institutions.

To investigate an outbreak of Staphylococcus aureus surgical-site infections.

Case–control study.

Pediatric cardiothoracic surgery service of a tertiary-care university medical center.

Molecular typing was used to identify healthcare workers who carried the epidemic strain.

Three children acquired surgical-site infections caused by a single strain of S. aureus. Fourteen (25%) of the staff members in the operating room and 17 (11%) on nursing units carried the epidemic strain (P = 01). A case–control study identified 4 healthcare workers who were associated statistically with the outbreak, 2 of whom (a cardiothoracic surgeon and a perfusionist) carried the epidemic strain in their nares. The surgeon also carried the epidemic strain on his hands. Each staff member who carried the epidemic strain was treated with mupirocin; those carrying the strain on their hands were required to wash their hands with chlorhexidine. The surgeon was not allowed to perform surgery until 2 of his hand cultures did not grow S. aureus.

Only three children were infected with the epidemic strain, but it was disseminated widely among staff who cared for children who underwent cardiothoracic surgery. No additional cases were identified after staff members who carried the epidemic strain were decolonized. Both classic epidemiologic methods and molecular typing techniques were necessary to identify the source and extent of this outbreak.

In 2000, the rate of primary bloodstream infections (BSIs) was double that in 1999 for intensive care unit (ICU) patients with triple lumen catheters, pulmonary artery catheters, or both. In December 1999, changes in products and practices related to site care were implemented as a cost-saving initiative.

To determine the factors contributing to an increase of BSIs after cost-saving measures for site care had been introduced.

Epidemiologic study involving prospective identification of infection.

A community teaching hospital.

Patients in a 20-bed, medical-surgical ICU identified as having triple lumen catheters, pulmonary artery catheters, or both and a primary BSI during 2000 and 2001.

Alcohol swab sticks were reintroduced and the frequency of transparent dressing changes and site care was increased. Inservice presentations were conducted on aseptic technique and posters were placed reviewing site care protocol for physicians and nurses.

The incidence of primary BSIs decreased significantly (P = .003) during a 3-month intervention and this decrease was sustained through the following 12 months.

Prolonging the interval between the change of transparent dressings from 3 times weekly to once weekly and switching from alcohol swab sticks to pads was associated with an increase in BSIs, which was controlled after returning to the original policy (Infect Control Hosp Epidemiol 2002;23:730-732)

To test the hypothesis that antibiotic therapy may promote recurrence of vancomycin-resistant Enterococcus (VRE) stool colonization in patients who have previously had three consecutive negative stool cultures obtained at least 1 week apart.

One-year prospective cohort study examining the effect of antibiotic therapy on recurrence and density of VRE stool colonization in patients who have cleared colonization. Pulsed-field gel electrophoresis (PFGE) was performed to determine whether recurrent VRE strains were the same clone as the previous colonizing strain.

A Department of Veterans Affairs medical center including an acute care hospital and nursing home.

All patients with at least one stool culture positive for VRE who subsequently had three consecutive negative stool cultures obtained at least 1 week apart.

Of the 16 patients who cleared VRE colonization, 13 received antibiotic therapy during the study period. Eight (62%) of the 13 patients who received antibiotics developed recurrent high-density VRE stool colonization (range, 4.9 to 9.1 log10 colony-forming units per gram) during a course of therapy. Five patients had VRE strains available for PFGE analysis; recurrent strains were unrelated to the prior strain in 3 patients, closely related in 1 patient, and indistinguishable in 1 patient.

Antibiotic therapy may be associated with recurrent high-density VRE stool colonization in many patients who have previously had three consecutive negative stool cultures. These patients should be screened for recurrent stool colonization when antibiotic therapy is administered.

To investigate the benefit of a hospitalwide feedback program regarding methicillin-resistant Staphylococcus aureus (MRSA), using annotated statistical process control charts.

Retrospective and prospective analysis of MRSA rates using statistical process control charts.

Twenty-four medical, medical specialty, surgical, intensive care, and cardiothoracic care wards and units at four Glasgow Royal Infirmary hospitals.

Annotated control charts were applied to prospective and historical monthly data on MRSA cases from each ward and unit during a 46-month period from January 1997 through September 2000. Results were fed back from December 1999 and then on a regular monthly basis to medical staff, ward managers, senior managers, and hotel services.

Monthly reductions in the MRSA acquisition rate started 2 months after the introduction of the feedback program and have continued to the present time. The overall MRSA rate currently is approximately 50% lower than when the program began and has become more consistent and less variable within departments throughout Glasgow Royal Infirmary. The control charts have helped to detect rate changes and manage resources more effectively. Medical and nursing staff and managers also report that they find this the most positive form of MRSA feedback they have received.

Feedback programs that provide current information to front-line staff and incorporate annotated control charts can be effective in reducing the rate of MRSA.

To examine the relationship between nurse staffing levels and the rate of nosocomial viral gastrointestinal infections (NVGIs) in a general pediatrics population.

Retrospective descriptive study.

A general pediatrics ward at The Hospital for Sick Children in Toronto, Ontario, Canada, a 320-bed, tertiary-care pediatric institution.

Forty-three NVGIs were detected in 37 patients of 2,929 admissions (1.3%). The monthly NVGI rate correlated significantly with the monthly night patient-to-nurse ratio (r = 0.56) and the monthly day patient-to-nurse ratio (r = 0.50). The nursing hours per patient-day during the preinfection period (PIP) were significantly lower than those during the nonpreinfection period (NPIP; 12.5 vs 13.0). There was no difference between the PIP and the NPIP day patient-to-nurse ratios (3.31 vs 3.32), but there was a significant difference between the PIP and the NPIP night patient-to-nurse ratios (3.26 vs 3.16). The incidence of NVGIs in the 72-hour period after any day when the nursing hours per patient-day were less than 10.5 was 6.39 infections per 1,000 patient-days, compared with 2.17 infections per 1,000 patient-days in periods with more than 10.5 nursing hours per patient-day (rate ratio, 2.94; 95% confidence interval, 2.16 to 4.01).

Nurse understaffing contributed to an increased NVGI rate in our general pediatrics population, and should be assessed as a risk factor in outbreak investigations.

To determine the diagnostic accuracy of an index of underlying disease severity (Horn's index) in identifying patients with a high probability of having nosocomial Clostridium difficile diarrhea as a complication of antimicrobial therapy.

A prospective cohort study of 252 adult patients admitted to the hospital and receiving antibiotics. Risk factors for C. difficile diarrhea were first determined retrospectively in a different cohort of 300 hospitalized patients (primary cobort) and then prospectively in this cohort of 252 hospitalized patients receiving antibiotics (secondary cohort). At the time of hospital admission, disease was rated by clinicians as mild (1), moderate (2), severe (3), or extremely severe (4) using a modified Horn's index. Multivariable logistic regression analysis was used to determine the odds ratio (OR) for C. difficile diarrhea associated with increasing levels of disease severity.

An urban teaching hospital affiliated with a medical school in Boston, Massachusetts.

The incidence of nosocomial C. difficile diarrhea was 8.7% in the primary cohort and 11% in the secondary cohort. In the prospective cohort study (secondary cohort), the OR for C. difficile diarrhea associated with extremely severe disease was 17.6 (95% confidence interval, 5.8 to 53.5). The sensitivity, specificity, and positive and negative predictive values of a Horn's index score of 3 or more (severe to extremely severe disease) as a predictor of nosocomial C. difficile diarrhea were 79%, 73%, 27%, and 96%, respectively.

These findings provide a means of early stratification of hospitalized patients receiving antibiotics according to their risk for nosocomial C. difficile diarrhea. Patients with severe to extremely severe disease at the time of admission may benefit from careful monitoring of antibiotic prescribing and early attention to infection control issues. In the future, these “high-risk” patients may benefit from prophylaxis studies of novel agents being developed to prevent C. difficile diarrhea.

To investigate an outbreak of Serratia marcescens bacteremia among patients after general anesthesia.

A case-control study.

A 304-bed, pediatric teaching hospital.

Twenty-three pediatric patients who developed S. marcescens bacteremia within 2 weeks after general anesthesia between June 15 and September 22, 1999, were compared with 46 age-matched control-patients who had undergone procedures on the same clinical services of the hospital during the same period.

Cases were distributed over a wide range of surgical services and were not correlated with exposure to any of the surgical, anesthesia, or nursing staff. Case-patients were significantly more likely than control-patients to have received cefazolin (odds ratio [OR], 11.1; 90% confidence interval [CI90], 1.9 to 24.3) or to have had perioperative placement of a central vascular catheter (OR, 4.2; CI90, 1.2 to 18.8). The timing of the procedures of patients who subsequently developed S. marcescens bacteremia was significantly associated with the shifts of one or more of five operating room technicians (OR, 2.9 to 6.8) who were responsible for preparing intravenous fluids used both to reconstitute perioperatively administered antibiotics and to prime central vascular catheter assemblies.

Our findings are consistent with a pattern of intermittent contamination due to periodic breaches in sterile technique, rather than a point-source of contamination. The unique challenges that such a procedural breakdown presents to an epidemiologic investigation are discussed. This outbreak stresses the importance of providing comprehensive training in antisepsis when multifunctional personnel are incorporated into an operating room work environment.

To evaluate the effectiveness of influenza vaccines against influenza-like illness (ILI) among nursing home residents.

Prospective, nonrandomized, cohort study.

Nine nursing homes during the 1998-1999 influenza season and 11 nursing homes during the 1999-2000 influenza season in Niigata Prefecture, Japan.

Six hundred ninety-nine residents and 440 healthcare workers (HCWs) during the first season, and 930 residents and 517 HCWs during the second season, with vaccination rates ranging from 0% to 97.7%.

Overall, ILI decreased from 24.3% during the 1998-1999 season to 8.8% during the 1999-2000 season. Multivariate analysis adjusted for several factors, including gender, age, underlying diseases, and resident and HCW vaccination rates, failed to demonstrate clear individual protection of residents (relative risk [RR], 1.42; P = .2 for the first season; RR, 0.95; P = .9 for the second season). However, vaccination rates of 60% or greater for residents and HCWs reduced the risk of ILI, and also could prevent outbreaks during the 2 seasons. Highly impaired activities of daily living and chronic respiratory diseases were significantly associated with increased ILI.

A high vaccination rate for both residents and HCWs may reduce the risk of ILI and institutional outbreaks in nursing homes

To characterize vancomycin-resistant enterococci (VRE) isolates and to evaluate the mode of dissemination of this pathogen in Brazil.

We collected 22 vancomycin-resistant Enterococcus faecium isolates from 6 medical centers in Sao Paulo, Brazil, and 1 isolate from a medical center in Curitiba, Brazil.

All Brazilian hospitals that had identified vancomycin-resistant E. faecium up to the beginning of this study (late 1999) contributed isolates to the study.

The isolates were susceptibility tested using the broth microdilution method and the E-test. The presence of vancomycin resistance genes (vanA, vanB, vanC1, vanC2-3, and vanD) was evaluated by polymerase chain reaction; molecular typing was performed by pulsed-field gel electrophoresis (PFGE).

The vanA gene was demonstrated in all vancomycin-resistant E. faecium, except for 1 isolate. None of the vancomycin resistance genes cited above was detected in the isolate from Curitiba, which was the first vancomycin-resistant E. faecium described in Brazil. All isolates were resistant to ampicillin and teicoplanin. The main clone remains susceptible to doxycycline and chloramphenicol, but intermediate to quinupristin-dalfopristin. PFGE analysis demonstrated 7 major PFGE patterns. A unique PFGE pattern with 4 subtypes was detected in 17 isolates from 4 different hospitals.

The results of our study indicate the occurrence of intra- and interhospital dissemination of VRE in Sao Paulo, Brazil.

To assess the healthcare burden, morbidity, and mortality of nosocomial Clostridium difficile-associated diarrhea (N-CDAD) in Canadian hospitals.

Laboratory-based prevalence study.

Nineteen acute-care Canadian hospitals belonging to the Canadian Hospital Epidemiology Committee surveillance program.

Hospitalized patients in the participating centers.

Laboratory-based surveillance was conducted for C. difficile toxin in stool among 19 Canadian hospitals from January to April 1997, for 6 continuous weeks or until 200 consecutive diarrhea stool samples had been tested at each site. Patients with N-CDAD had to fulfill the case definition. Data collected for each case included patient demographics, length of stay, extent of diarrhea, complications of CDAD, CDAD-related medical interventions, patient outcome, and details of death.

We found that 371 (18%) of 2,062 tested patients had stools with positive results for C. difficile toxin, of whom 269 (13%) met the case definition for nosocomial CDAD. Of these, 250 patients (93%) had CDAD during their hospitalization, and 19 (7%) were readmitted because of CDAD (average readmission stay, 13.6 days). Forty-one patients (15.2%) died, of whom 4 (1.5% of the total) were considered to have died directly or indirectly of N-CDAD. The following N-CDAD-related morbidity was noted: dehydration, 3%; hypokalemia, 2%; gastrointestinal hemorrhage requiring transfusion, 1%; bowel perforation, 0.4%; and secondary sepsis, 0.4%. The cost of N-CDAD readmissions alone was estimated to be a minimum of $128,200 (Canadian dollars) per year per facility.

N-CDAD is a common and serious nosocomial infectious complication in Canada, is associated with substantial morbidity and mortality, and imposes an important financial burden on healthcare institutions.

To identify the contamination source of a cluster of eight positive Mycobacterium tuberculosis isolates from one laboratory session.

Spoligotyping was performed on M. tuberculosis isolates processed during one laboratory session. Laboratory and sputum induction protocols and records were reviewed. Sputum induction staff were interviewed. An environmental assessment of the sputum induction booth was performed.

Spoligotyping identified a unique strain of susceptible M. tuberculosis from five induced sputa collected at Clinic A on the same day. Three specimens processed concurrently from other clinics had spoligotypes different from each other and from the cluster strain. A laboratory investigation revealed no procedural lapses. Sputum induction records from Clinic A indicated that patient 1 in the sputum induction booth had prior culture-confirmed tuberculosis. Patient 2 had a history of a drug-resistant strain. Patient 3 had completed tuberculosis treatment, with positive cultures 7 months earlier. Patients 4 and 5 were new to the clinic and had no subsequent positive M. tuberculosis specimens. The sputum induction booth was working within normal parameters. Sputum induction that day was overseen by a new employee with limited training and no supervision. A review of the sputum induction protocol identified ambiguity regarding care of the ultrasonic nebulizer between patients, which may have led to reuse of the discarded nebulizer solution from patient 1.

A break in the sputum induction protocol may have contributed to contamination of patient specimens. Sputum induction is complicated, mandating adequate staff training and supervision and patient preparation. Spoligotyping identified a potential source of M. tuberculosis contamination.(Infect Control Hosp Epidemiol 2002;23:580-583).