Nosocomial infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are increasing. Only a few studies of MRSA infective endocarditis have been conducted, and none have reported its risk factors. We sought to determine the host-related risk factors for infective endocarditis in patients with nosocomial MRSA bacteremia.

A 2,000-bed, university-affiliated, tertiary-care hospital.

Thirty-one patients with nosocomial MRSA infective endocarditis between October 1996 and May 2003.

A retrospective chart review was conducted. Data were compared with those from a control group of patients with nosocomial MRSA bacteremia. Logistic regression was used to identify independent risk factors for nosocomial infective endocarditis.

Compared with patients who had nosocomial MRSA bacteremia and no infective endocarditis, patients who had infective endocarditis had a higher incidence of chronic liver disease and a lower incidence of immunodeficiency. The risk of developing infective endocarditis was approximately 10% for patients with nosocomial MRSA bacteremia.

Patients with MRSA bacteremia and underlying chronic liver disease were prone to infective endocarditis. (Infect Control Hosp Epidemiol 2005;26:654-657)

Bordetella pertussis is highly contagious, and because immunity wanes after vaccination, it continues to be a cause of cough among adults.

To describe the healthcare services used and productivity losses accrued by healthcare workers (HCWs) missing work due to pertussis.

After 3 pertussis cases were confirmed among HCWs, all hospital employees and patients with a cough were screened between November 2000 and March 2001. Each potential case underwent diagnostic tests and received antibiotics (spiramycin or azithromycin) when appropriate. Symptomatic employees were not allowed to return to work until they received an antibiotic for at least 5 days. Services used (physician visits and calls, antibiotics, diagnostic tests, hospitalization, and treatment provided to their contacts) were combined with cost estimates (in 2002 euros) for these services in France.

Ninety-one potential cases were identified (77 HCWs, 12 patients, and 2 family members). Of them, 89% received antibiotics and 22% had at least one contact who was also treated. Approximately half (55%) of the HCWs who were cases missed 5 days of work. Four patients were admitted to the hospital as a result of the infection. The average medical cost was 297 euros per potential case: diagnostic tests accounted for 32% and hospitalization for 31%. Total cost (medical and productivity) was 46,661 euros for 91 cases, 42% from productivity losses. An investigation to identify these potential cases also accrued additional costs.

Serious adverse health and economic consequences arose from transmission of pertussis among HCWs, their families, and patients.

Acinetobacter baumannii has emerged as an opportunistic pathogen among acutely ill patients, especially those with thermal injury. A prospective 8-month study was conducted to describe the clinical and molecular epidemiology of multidrug-resistant A. baumannii affecting a single hospital.

Univariate analysis comparing Smal macrorestriction patterns of A. baumannii generated by pulsed-field gel electrophoresis (PFGE) versus clinical and demographic risk factors.

A total of 200 isolates from 76 patients were collected, of which 185 isolates from 76 patients were analyzed by PFGE. A total of 17 distinct PFGE clonal types were identified. One clonal type (strain A) represented 129 isolates from 49 patients. A group of related clonal types (strain A variants) were identified as 40 isolates from 20 patients. The only risk factor other than geographic location associated with the presence of strain A was prior treatment with antibiotics active against gram-negative bacteria (P = .0015). The two clonal types differed in antibiotic resistance profiles: 25% of strain A isolates, the dominant strain in the burn unit, were susceptible to at least one antibiotic tested. In contrast, approximately 80% of the other strain types were susceptible to at least one antibiotic and were cultured from patients admitted elsewhere in the hospital. No combination of antibiotics was observed to yield additive or synergistic activity.

Clonally related strains of Acinetobacter that differ in susceptibility patterns may coexist within a single hospital, dependent on the selective pressure related to antibiotic exposure.

To report an outbreak of Pichia anomala fungemia that occurred in a Brazilian pediatric intensive care unit (ICU) from October 2002 to January 2004.

Unmatched case-control study.

We randomly selected four control-patients for each case-patient from a list of all patients admitted to the ICU for at least 48 hours during the outbreak. A second control group was composed of all consecutive patients with nosocomial candidemia in the ICU during the outbreak. An environmental study was performed, and genetic relatedness among the clinical isolates was characterized by randomly amplified polymorphic DNA assay.

During the study period, 1,046 children were admitted to the pediatric ICU, 17 of whom developed P. anomala fungemia (attack rate, 1.6%). The median age was 1.1 years, and the main underlying conditions were congenital malformations (35.3%) and neoplastic diseases (11.8%). The overall mortality rate was 41.2%. Two patients received no antifungal treatment; all of the others were treated with amphotericin B. On multivariate analysis, only the presence of a central venous catheter was significantly associated with P. anomala fungemia. The yeast was not found on healthcare workers' hands or in the environment. Molecular studies showed that the outbreak was caused by a single strain. The distribution of risk factors was similar between patients with P. anomala fungemia and control-patients with candidemia.

This study highlights the importance of P. anomala as an emerging nosocomial fungal pathogen. Patients with P. anomala fungemia seem to have risk factors in common with those who have candidemia.

To describe, during a 6-year period, multidrug-resistant bacterial carriage in an intensive care unit (ICU).

Prospective survey of 2,235 ICU patients with methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum beta-lactamase–producing Enterobacteriaceae (ESBL-E).

A surgical ICU in a tertiary-care teaching hospital.

All admitted patients.

Nasal and rectal swabs were performed at admission and weekly thereafter. There was nasal application of mupirocin for MRSA carriers and selective digestive decontamination with local antibiotics for ESBL-E carriers.

The swab compliance rate was 82% at admission and 51% during ICU stay. The rates of MRSA carriage or infection were 4.2 new cases per 100 admissions and 7.9 cases per 1,000 patient-days during ICU stay. The rates of ESBL-E carriage or infection were 0.4 new case per 100 admissions and 3.9 cases per 1,000 patient-days during ICU stay. Importation of MRSA increased significantly over time from 3.2 new cases per 100 admissions during the first 3 years to 5.5 during the last 3 years. The rate of ICU-acquired ESBL-E decreased from 5.5 cases per 1,000 patient-days during the first 3 years to 1.9 cases during the last 3 years. Nasal and digestive decontamination had low efficacy in eradicating carriage.

MRSA remained poorly controlled throughout the hospital and was not just a problem in the ICU. MRSA thus requires more effective measures throughout the hospital. ESBL-E was mainly an ICU pathogen and our approach resulted in a clear decrease in the rate of acquisition in the ICU over time.

To analyze and model the patient and healthcare system factors that may interfere with the appropriate administration of surgical antimicrobial prophylaxis.

Between 1994 and 1998, surgical-site surveillance data were collected prospectively for a cohort of eligible surgical patients. For all cases, and each individual procedure (cardiothoracic, colonic, gynecologic, orthopedic, or vascular), forward stepwise multiple logistic regression was applied to relate key hospital and patient factors to an effective first prophylactic dose (ie, appropriate administration time, dose, route, and drug).

A 450-bed, tertiary-care teaching hospital in Canada.

A total of 4,835 patients admitted for surgical procedures who required antimicrobial prophylaxis.

Factors positive for an effective first prophylactic dose for all cases were when an order was written (OR, 19.7; CI95, 9.1–42.7; P < .001) and given in the operating room (OR, 13.9; Cl95, 7.5–25.6; P < .001). Factors negative for an effective first prophylactic dose were beta-lactam allergy (OR, 0.49; CI95, 0.4–0.61; P < .001) and same-day surgery (OR, 0.57; CI95, 0.4–0.82; P < .001).

With few exceptions, the four factors included in the procedure models showed that when a preoperative order was written or the antibiotic was given in the operating room, a patient was more likely to receive an effective first prophylactic dose. Conversely, when a patient had a beta-lactam allergy or the surgery was performed on the day the patient was admitted, the administration of an effective first prophylactic dose was less likely.

To assess the efficacy of a standard cleaning and sterilization protocol employed during reuse of cardiac electrophysiology catheters on the infectivity of duck hepatitis B virus (DHBV; a surrogate for human hepatitis B virus), bovine viral diarrhea virus (BVDV; a surrogate for human hepatitis B virus), and human Coxsackie type B3 virus (CB3).

Public health virology laboratory.

Studies were performed on the distal, electrode-containing segments of 120 electrophysiology catheters previously used in up to 10 clinical procedures. Catheter segments were immersed for 1 hour in blood infected with high titers of DHBV, BVDV, or CB3. After air drying for 2 hours, subgroups of 8 catheters were subjected to no treatment, washing in general-purpose detergent, washing in enzyme cleaner, sterilization in ethylene oxide, or the full protocol of sequential detergent-enzyme cleaner-ethylene oxide exposure. Presence of residual virus was assessed by nucleic acid detection and infectivity studies.

DHBV nucleic acid was detected on catheters after individual steps and the full protocol, whereas BVDV and CB3 nucleic acids were detected after individual steps but not the full protocol. These findings were associated with the presence of infectious DHBV and CB3, but not BVDV, on catheters after washing in detergent or enzyme cleaner. However, ethylene oxide alone or the full protocol reduced infectivity of all three viruses to undetectable levels.

These experimental studies provide strong evidence that appropriate cleaning and sterilization of reused electrophysiology catheters inactivates blood-borne viruses such as hepatitis B and C and Coxsackie type B3.

Coagulase-negative staphylococci are both an important cause of nosocomial bloodstream infections and the most common contaminants of blood cultures. Judging the clinical significance of coagulase-negative staphylococci is vital but often difficult and can have a profound impact on an institution's bloodstream infection rates. Our objective was to develop an algorithm to assist in determining the clinical significance of coagulase-negative staphylococci.

A single experienced reviewer examined the medical records of 960 consecutive patients with positive blood cultures in a tertiary-care referral teaching hospital. Four hundred five of the cultures contained coagulase-negative staphylococci. A determination of clinical significance was made and the performances of various published algorithms that contained readily available clinical and laboratory data were compared.

Eighty-nine (22%) of the episodes were considered significant, whereas 316 were contaminants. Patients with bacteremia were significantly more likely to be neutropenic and exhibit signs of sepsis syndrome. The algorithm with the best combined sensitivity (62%) and specificity (91%) for determining the clinical significance of coagulase-negative staphylococci was defined as at least two blood cultures positive for coagulase-negative staphylococci within 5 days, or one positive blood culture plus clinical evidence of infection, which includes abnormal white blood cell count and temperature or blood pressure.

Use of this algorithm could potentially reduce misclassification of nosocomial bloodstream infections and inappropriate use of vancomycin for positive blood cultures likely to represent contamination (Infect Control Hosp Epidemiol 2005;26:559-566).

To assess data on the epidemiology of nosocomial infection (N1) among neurologic intensive care patients.

Prospective periodic surveillance study.

An 8-bed neurologic intensive care unit (ICU).

All those admitted for more than 24 hours during five 3-month periods between January 1999 and March 2003.

Standardized surveillance within the German infection surveillance system.

Three hundred thirty-eight patients with a total of 2,867 patient-days and a mean length of stay of 8.5 days were enrolled during the 15-month study period. A total of 71 NIs were identified among 52 patients. Urinary tract infections (UTIs) were the most frequent N1 (36.6%), followed by pneumonia (29.6%) and bloodstream infections (BSIs) (15.5%). The overall incidence and incidence density of NIs were 21.0 per 100 patients and 24.8 per 1,000 patient-days, respectively. Incidence densities were 9.8 UTIs per 1,000 urinary catheter-days (CI95, 6.4-14.4), 5.6 BSIs per 1,000 central venous catheter-days (CI95, 2.8-10.0), and 12.8 cases of pneumonia per 1,000 ventilation-days (CI95, 8.0-19.7). Device-associated UTI and pneumonia rates were in the upper range of national and international reference data for medical ICUs, despite the intensive infection control and prevention program in operation in the hospital.

Neurologic intensive care patients have relatively high rates of device-associated nosocomial pneumonia and UTI. For a valid comparison of surveillance data and implementation of targeted prevention strategies, we would strongly recommend provision of national benchmarks for the neurologic ICU setting.

To determine whether randomly selected intravenous (IV) antimicrobial doses dispensed from an inpatient pharmacy were administered.

This was a prospective, cross-sectional study in which dose administration was confirmed by direct observation and by assessment of the medication administration record (MAR). A retrospective analysis of the return rate of unused IV antimicrobial doses was performed subsequently.

Medical and surgical intensive care units (ICUs) and non-ICUs of a 550-bed urban public teaching hospital.

Hospitalized patients with an order in the pharmacy database for an IV antimicrobial during 9 non-consecutive weekdays in June 1999.

Of 397 doses, 221 (55.7%) assessed by bedside observation and 238 (59.9%) assessed by MAR review were classified as administered; 139 doses (35.0%) were dispensed but changes in the drug order or the patient's status prevented their administration. In the subsequent assessment, of 745 IV antimicrobial doses dispensed during 24 hours, 322 (43.2%) were returned to the pharmacy unused; 423 (56.8%) of the doses—consistent with our prior observations—were presumably administered.

Because computerized pharmacy data may overestimate actual antimicrobial consumption, such data should be validated when used in studies of hospital antimicrobial use. Dispense-return analysis offers a simple validation method.

To compare the efficacies of ethylene oxide gas (EOG), hydrogen peroxide gas plasma (PLASMA), and low-temperature steam formaldehyde (LTSF) sterilization methods.

The efficacies of EOG, PLASMA, and LTSF sterilization were tested using metal and plastic plates, common medical instruments, and three process challenge devices with narrow lumens. All items were contaminated with Bacillus stearothermophilus spores or used a standard biological indicator.

EOG and LTSF demonstrated effective killing of B. stearothermophilus spores, with or without serum, on plates, on instruments, and in process challenge devices. PLASMA failed to adequately sterilize materials on multiple trials in several experiments, including two of three plates, two of three instruments, and all process challenge devices.

Our results suggest that PLASMA sterilization may be unsuccessful under certain conditions, particularly when used for items with complex shapes and narrow lumens. Alternatively, LTSF sterilization demonstrates excellent efficacy and is comparable to EOG sterilization. LTSF could potentially act as a substitute if EOG becomes unavailable due to environmental concerns.

To detect putative clonal dissemination of multidrug-resistant, coagulase-negative staphylococci (CNS) in a university hospital in northern Sweden.

All consecutive routine clinical samples from our hospital were screened during two periods (November and December 2001 and September and October 2002) for the presence of multidrug-resistant (defined as resistant to oxacillin, clindamycin, co-trimoxazole, gentamicin, and fusidic acid, but susceptible to vancomycin) isolates of CNS. Genetic similarity between isolates was analyzed using pulsed-field gel electrophoresis (PFGE) and a computer program.

Seventy multidrug-resistant isolates from 62 patients were identified, 28 during the 2001 period and 42 during the 2002 period. All isolates except one, which was Staphylococcus haemolyticus, were identified as S. epidermidis. Multidrug-resistant CNS were isolated in samples obtained from 24 different wards. Two subgroups (group A and group B) of S. epidermidis that differed by approximately 40% in PFGE band similarity were identified. Group A consisted of 44 isolates with a PFGE band similarity of greater than 70% that included 6 subgroups consisting of 3 to 16 isolates that expressed a 100% similarity. These isolates were identified during both sampling periods in cultures performed in 18 different wards. A clonal origin could not be excluded for some of the remaining 26 isolates belonging to group B, but none had identical PFGE patterns, suggesting a more diverse origin.

The results of this study suggest clonal spread of multidrug-resistant CNS within our hospital and that some clones are endemic in the hospital environment.

To evaluate the impact of methicillin resistance in Staphylococcus aureus on mortality, length of hospitalization, and hospital charges.

A cohort study of patients admitted to the hospital between July 1, 1997, and June 1, 2000, who had clinically significant S. aureus bloodstream infections.

A 630-bed, urban, tertiary-care teaching hospital in Boston, Massachusetts.

Three hundred forty-eight patients with S. aureus bacteremia were studied; 96 patients had methicillin-resistant S. aureus (MRSA). Patients with methicillin-susceptible S. aureus (MSSA) and MRSA were similar regarding gender, percentage of nosocomial acquisition, length of hospitalization, ICU admission, and surgery before S. aureus bacteremia. They differed regarding age, comorbidities, and illness severity score.

Similar numbers of MRSA and MSSA patients died (22.9% vs 19.8%; P = .53). Both the median length of hospitalization after S. aureus bacteremia for patients who survived and the median hospital charges after S. aureus bacteremia were significantly increased in MRSA patients (7 vs 9 days, P = .045; $19,212 vs $26,424, P = .008). After multivariable analysis, compared with MSSA bacteremia, MRSA bacteremia remained associated with increased length of hospitalization (1.29 fold; P = .016) and hospital charges (1.36 fold; P = .017). MRSA bacteremia had a median attributable length of stay of 2 days and a median attributable hospital charge of $6,916.

Methicillin resistance in S. aureus bacteremia is associated with significant increases in length of hospitalization and hospital charges.

To identify the independent effect of pressure ulcers on excess length of stay and control for all observable factors that may also contribute to excess length of stay. Hospitalized patients who develop a pressure ulcer during their hospital stay are at a greater risk for increased length of stay as compared with patients who do not.

Cross-sectional, observational study.

Tertiary-care referral and teaching hospital in Australia.

Two thousand hospitalized patients 18 years and older who had a minimum stay in the hospital of 1 night and admission to selected clinical units.

Two thousand participants were randomly selected from 4,500 patients enrolled in a prospective survey conducted between October 2002 and January 2003. Quantile median robust regression was used to assess risk factors for excess length of hospital stay.

Having a pressure ulcer resulted in a median excess length of stay of 4.31 days. Twenty other variables were statistically significant at the 5% level in the final model.

Pressure ulcers make a significant independent contribution to excess length of hospitalization beyond what might be expected based on admission diagnosis. However, our estimates were substantially lower than those currently used to make predictions of the economic costs of pressure ulcers; existing estimates may overstate the true economic cost.

To study the clinical and molecular epidemiology of vancomycin-resistant Enterococcus faecium organisms causing catheter-related bacteremia in patients with cancer.

Retrospective case-control study.

University of Texas M. D. Anderson Cancer Center, a tertiary-care hospital in Houston, Texas.

Case-patients were patients with cancer who had catheter-related vancomycin-resistant E. faecium bacteremia and control-patients were patients with cancer and vancomycin-resistant E. faecium gastrointestinal colonization without infection.

Ten case-patients with catheter-related vancomycin-resistant E. faecium bacteremia were compared with 30 control-patients with gastrointestinal colonization by vancomycin-resistant E. faecium. Patients with catheter-related vancomycin-resistant E. faecium bacteremia were more likely to have required mechanical ventilation (P < .01), received total parenteral nutrition (P < .01), and had polyurethane catheters (P < .01) inserted in the femoral vein (P = .01). With the use of pulsed-fleld gel electrophoresis, 4 of the 10 catheter-related vancomycin-resistant E. faecium bacteremia isolates were genetically indistinguishable, whereas only 2 of the 30 control vancomycin-resistant E. faecium isolates displayed this same DNA pattern (P = .03).

This study suggests that catheter-related vancomycin-resistant E. faecium bacteremia occurs more frequently in patients who receive total parenteral nutrition, mechanical ventilation, and femoral catheters. (Infect Control Hosp Epidemiol 2005;26:658-661)

To assess the level of knowledge regarding and attitudes toward standard and isolation precautions among healthcare workers in a hospital.

A confidential, self-administered questionnaire survey was conducted in a random sample of 1,500 nurses and 500 physicians in a large teaching hospital.

A total of 1,241 questionnaires were returned (response rate, 62%). The median age of respondents was 39 years; 71.9% were women and 21.2% had senior staff status. One-fourth had previously participated in specific training regarding transmission precautions for pathogens conducted by the infection control team. More than half (55.9%) gave correct answers to 10 or more of the 13 knowledge-type questions. The following reasons for noncompliance with guidelines were judged as “very important”: lack of knowledge (47%); lack of time (42%); forget-Mness (39%); and lack of means (28%). For physicians and healthcare workers in a senior position, lack of time and lack of means were significantly less important (P < .0005). On multivariate linear regression, knowledge was independently associated with exposure to training sessions (coefficient, 0.33; 95% confidence interval, 0.08 to 0.57; P = .009) and less professional experience (coefficient per increasing professional experience, -0.024; 95% confidence interval, -0.035 to -0.012; P < .0005).

Despite a training effort targeting opinion leaders, knowledge of transmission precautions for pathogens remained insufficient. Nevertheless, specific training proved to be the major determinant of “good knowledge”.

Comorbid conditions have complicated previous analyses of the consequences of methicillin resistance for costs and outcomes of Staphylococcus aureus bacteremia. We compared costs and outcomes of methicillin resistance in patients with S. aureus bacteremia and a single chronic condition.

We conducted a prospective cohort study of hemodialysis-dependent patients with end-stage renal disease and S. aureus bacteremia hospitalized between July 1996 and August 2001. We used propensity scores to reduce bias when comparing patients with methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) S. aureus bacteremia. Outcome measures were resource use, direct medical costs, and clinical outcomes at 12 weeks after initial hospitalization.

Fifty-four patients (37.8%) had MRSA and 89 patients (62.2%) had MSSA. Compared with patients with MSSA bacteremia, patients with MRSA bacteremia were more likely to have acquired the infection while hospitalized for another condition (27.8% vs 12.4%; P = .02). To attribute all inpatient costs to S. aureus bacteremia, we limited the analysis to 105 patients admitted for suspected S. aureus bacteremia from a community setting. Adjusted costs were higher for MRSA bacteremia for the initial hospitalization ($21,251 vs $13,978; P = .012) and after 12 weeks ($25,518 vs $17,354; P = .015). At 12 weeks, patients with MRSA bacteremia were more likely to die (adjusted odds ratio, 5.4; 95% confidence interval, 1.5 to 18.7) than were patients with MSSA bacteremia.

Community-dwelling, hemodialysis-dependent patients hospitalized with MRSA bacteremia face a higher mortality risk, longer hospital stays, and higher inpatient costs than do patients with MSSA bacteremia.

Catheter colonization is a necessary but poorly characterized step in the pathogenesis of catheter-related infections. Colonization dynamics of central venous hemodialysis catheters were studied with emphasis on coagulase-negative staphylococci (CoNS) and their population genetics, antibiotic resistance, and biofilm formation. The homogeneity of CoNS colony morphotypes was evaluated.

Prospective, longitudinal study during 1,158 catheter-days with microbiological analysis of skin swabs, weekly catheter blood and brush samples, and catheter tips.

Hemodialysis unit of a university hospital.

Twenty-six patients with 24 non-tunneled and 5 tunneled catheters.

Nineteen (65.5%) of the catheters became colonized, 17 by CoNS. CoNS colonization of the inner lumen was observed in 17.2% of the catheters and was first detectable after 3 weeks. Colonization of the outer surface occurred in 44.8% of the catheters within a minimum of 2 weeks. PFGE of 53 CoNS revealed 10 clones and 20 unique isolates. Isolates from clones were more frequent in catheter blood and brush cultures than were unique isolates (41% vs 15%), were resistant to more antibiotics (median, 7 vs 2), and tended to more often carry the icaA gene (64.1% vs 40%). Four (23.5%) of the catheters showed colonization with a mixture of CoNS based on PFGE. The time from catheter insertion to such mixed CoNS colonization was longer than that for colonization with one CoNS PFGE pattern only (42 vs 25 days).

Colonization of hemodialysis catheters is dominated by multidrug-resistant, icaA-positive CoNS clones. Mixed CoNS colonization occurs, but is delayed, suggesting a process of sequential superinfection (Infect Control Hosp Epidemiol 2005;26:567-574).