Enterococcal bloodstream infections (BSIs) cause morbidity and mortality in children. This study aims to describe the epidemiological characteristics of enterococcal BSI, to determine the risk factors for vancomycin-resistant Enterococcus (VRE) BSI, and to compare outcomes of VRE BSI and vancomycin-susceptible Enterococcus (VSE) BSI in this population.

A retrospective cohort study at a 418-bed tertiary care children's hospital in Philadelphia, Pennsylvania, examined the epidemiological characteristics of children hospitalized with enterococcal BSI during the period from 2001 through 2006. A nested case-control study compared patients with VRE BSI with control patients with VSE BSI. Analysis included regression modeling to identify independent risk factors for VRE BSI.

We identified 339 patients with enterococcal BSI during the study period, including 39 patients with VRE infection. Fifty-three patients (16%) died before hospital discharge. Risk factors for VRE included long-term receipt of mechanical ventilation (adjusted odds ratio [OR], 5.40 [95% confidence interval {CI}, 1.28-6.48]), receipt of immunosuppressive medications during the preceding 30 days (adjusted OR, 2.88 [95% CI, 1.40-20.78]), use of vancomycin during the 2 weeks before onset of bacteremia (adjusted OR per day of vancomycin use, 1.25 [95% CI, 1.14-1.38]), and older age (adjusted OR, 1.08 [95% CI, 1.03-1.14]). VRE BSI was not associated with an increased length of stay after onset of bacteremia (0.77 days [95% CI, 0.55-1.07 days]). Mortality was higher for VRE BSI, but the difference was not statistically significant (adjusted OR, 1.94 [95% CI, 0.78-4.8]).

Most enterococcal BSI in children was caused by VSE. Risk factors for VRE BSI included receipt of vancomycin, long-term receipt of mechanical ventilation, immunosuppression, and older age. Differences in length of stay and mortality were not detected.

Active surveillance to detect patients colonized with methicillin-resistant Staphylococcus aureus (MRSA) is increasingly practiced in healthcare settings. However, inpatients may already become sources of transmission before appropriate precautions are implemented.

To examine the frequency of MRSA contamination of commonly touched skin and environmental surfaces before patient carriage status became known.

We conducted a 6-week prospective study of patients who were identified by use of polymerase chain reaction (PCR) at hospital admission as having nasal MRSA colonization. Skin and environmental contamination was assessed within hours of completion of PCR screening.

There were 116 patients identified by PCR screening as having nasal MRSA colonization during the period from mid-April to May 2008, of whom 83 (72%) were enrolled in our study. Overall, MRSA was detected on the skin of 38 (51%) of 74 patients and in the environment of 37 (45%) of 83 patients Of 83 environmental culture samples, 63 (76%) were obtained within 7 hours after PSR results became available, and 73 (88%) were obtained before wards were notified of PCR Results. Of the 83 MRSA-colonized patients, 15 (18%) had contaminated their environment 25 hours after admission, and 29 (35%) had contaminated their environment 33 hours after admission. Thirty-two (39%) of the 83 patients had roommates, 13 (41%) of whom contaminated their environment. The median interval from admission to PCR result was 20 hours, and the median interval from PCR result to notification was 23 hours. An increased quantity of MRSA cultured from a nasal sample was significantly associated with contamination.

Before any contact precautions can be implemented, newly identified MRSA carriers frequently have contaminated their environment with MRSA and have contamination of commonly examined skin sites. In hospitals that perform active surveillance, strategies are needed to minimize delays in screening or to preemptively identify patients at high risk for disseminating MRSA.

To determine differences in healthcare costs between cases of methicillin-susceptible Staphylococcus aureus (MSSA) infection and methicillin-resistant S. aureus (MRSA) infection in adults.

Retrospective study of all cases of S. aureus infection.

Department of Veterans Affairs hospital and associated clinics.

There were 390 patients with MSSA infections and 335 patients with MRSA infections.

We used medical records, accounting systems, and interviews to identify services rendered and costs for Minneapolis Veterans Affairs Medical Center patients with S. aureus infection with onset during the period from January 1, 2004, through June 30, 2006. We used regression analysis to adjust for patient characteristics.

Median 6-month unadjusted costs for patients infected with MRSA were $34,657, compared with $15,923 for patients infected with MSSA. Patients with MRSA infection had more comorbidities than patients with MSSA infection (mean Charlson index 4.3 vs 3.2; P < .001). For patients with Charlson indices of 3 or less, mean adjusted 6-month costs derived from multivariate analysis were $51,252 (95% CI, $46,041–$56,464) for MRSA infection and $30,158 (95% CI, $27,092–$33,225) for MSSA infection. For patients with Charlson indices of 4 or more, mean adjusted costs were $84,436 (95% CI, $79,843–$89,029) for MRSA infection and $59,245 (95% CI, $56,016–$62,473) for MSSA infection. Patients with MRSA infection were also more likely to die than were patients with MSSA infection (23.6% vs 11.5%; P < .001). MRSA infection was more likely to involve the lungs, bloodstream, and urinary tract, while MSSA infection was more likely to involve bones or joints; eyes, ears, nose, or throat; surgical sites; and skin or soft tissue (P < .001).

Resistance to methicillin in S. aureus was independently associated with increased costs. Effective antimicrobial stewardship and infection prevention programs are needed to prevent these costly infections.

In 2007–2008, several US hospitals reported summertime increases in the number of clinical blood cultures positive for Bacillus species, which are common environmental bacteria.

To investigate increased rates of isolation of Bacillus species from blood cultures, identify risk factors, and recommend control strategies.

Survey and case-control study.

Multiple hospitals, including a cancer center.

We surveyed 24 facilities that reported increases. We also conducted a field investigation at a hospital with a high rate, reviewing charts, collecting clinical and environmental isolates, and observing infection control procedures. A case-control study compared inpatient case patients who had any blood culture positive for Bacillus with unmatched control patients who had a blood culture with no growth during June-August 2008.

Among surveyed facilities, mean monthly rates rose from 25 to a peak of 75 Bacillus-positive blood cultures per 10,000 blood cultures performed during the period June-August. At the hospital where the case-control investigation was conducted, for most case patients (75%), the Bacillus-positive blood cultures represented contamination or device colonization rather than infection. We enrolled 48 case patients and 48 control patients; in multivariate analysis, only central venous access device use was significantly associated with case status (odds ratio, 14.0; P < .01). Laboratory testing identified at least 12 different Bacillus species (non-anthracis) among the isolates. Observation of infection control procedures revealed variability in central line care and blood sample collection techniques.

Periodic increases in the environmental load of Bacillus species may occur in hospitals. Our investigation indicated that at one facility, these increases likely represented a pseudo-outbreak of Bacillus species colonizing central venous lines or their accessories, such as needleless connector devices. Vigilant attention should be paid to infection control practices when collecting blood samples for culture, to minimize the risk of contamination by environmental microorganisms.

Extended-spectrum β-lactamase (ESBL)–producing strains of bacteria have become a major public health concern. In the present study, the incidence of carriage of ESBL-producing strains was analyzed for general trends and seasonality.

Monthly data on ESBL-producing strains were collected retrospectively at 2 large university hospitals in Germany. The mean monthly temperatures for the 2 settings were collected from Germany's national meteorological service. Multivariable time series analyses were performed to explain variations in the monthly incidence densities of carriage of ESBL-producing bacteria (number of cases involving ESBL-producing Escherichia coli and/or Klebsiella species per 1,000 patient days). For the final models, we incorporated variables for the ascending linear trends and other variables representing the mean monthly temperature.

Our models demonstrated that there was an increasing trend in the incidences of carriage of ESBL-producing bacteria. In addition, the incidences of carriage of all ESBL-producing bacteria responded positively to the mean temperature, meaning that during the summer, more cases involving ESBL-producing bacteria were detected than during the winter. The same methodology was also applied to the incidence of methicillin-resistant Staphylococcus aureus carriage, but no association was found with the mean temperature.

In the present study, we demonstrated that the monthly incidence of carriage of ESBL-producing bacteria was highly correlated with the mean monthly temperature, a fact that should be considered in experimental studies as an additional parameter influencing the incidence of ESBL-producing bacteria.

We evaluated the impact of education and an antifungal stewardship program for candidiasis on prescribing practices, antifungal consumption, Candida species infections, and estimated costs at a Thai tertiary care hospital.

A hospital-wide, quasi-experimental study was conducted for 1.5 years before the intervention and 1.5 years after the implementation of an antifungal stewardship program. Inpatient antifungal prescriptions were prospectively observed, and patients' demographic, clinical, and administrative-cost data were collected. Interventions included education, introduction of an antifungal hepatic and/or renal dose adjustment tool, antifungal prescription forms, and prescription-control strategies.

After the intervention, there was a 59% reduction in antifungal prescriptions (from 194 to 80 prescriptions per 1,000 hospitalizations; P < .001). Inappropriate antifungal use decreased (from 71% to 24%; P < .001), a sustained reduction in antifungal use was observed (r = 0.83; P < .001), and fluconazole use decreased (from 242 to 117 defined daily doses per 1,000 patient-days; P < .001). Reductions in the incidence of infection with Candida glabrata (r = 0.69; P < .001) and Candida krusei (r = 0.71; P < .001) were observed, whereas the incidence of infection with Candida albicans (r = —0.81; P < .001) increased. Total cost savings were US$31,615 during the 18-month postintervention period.

Implementation of an antifungal stewardship program was associated with appropriate antifungal drug use, improved resource utilization, and cost savings.

To determine whether an earlier determination of staphylococcal species and their antibiotic susceptibility decreases unnecessary antistaphylococcal treatment and/or facilitates earlier appropriate treatment.

We used the Xpert MRSA/SA BC system (Cepheid) for immediate determination of species and their drug susceptibility in patients whose blood cultures revealed gram-positive cocci in clusters. We compared the treatment of patients whose physicians received early notification of these results (group 1) with the treatment of patients in a historical cohort with delayed reporting after traditional microbiological studies (group 2). Outcomes were analyzed according to whether blood culture was positive for Staphylococcus species other than S. aureus, methicillin-susceptible S. aureus (MSSA), or methicillin-resistant S. aureus (MRSA) and whether the drugs used were appropriate for methicillin-susceptible or methicillin-resistant staphylococci (hereafter referred to as “MSS drug” or “MRS drug” therapy, respectively).

There were 44 (76%) of 58 patients with bacteremia due to Staphylococcus species other than S. aureus in group 1 and 58 (55%) of 106 patients with bacteremia due to Staphylococcus species other than S. aureus in group 2 who received no antistaphylococcal antibiotics (P <.01). Five (6%) of 89 patients in group 1 and 31 (25%) of 123 patients in group 2 received 0-168 hours (0-7 days) of MRS drug therapy (P < .01). Among patients with MSSA bacteremia, the mean time to initiation of appropriate therapy was 5.2 hours in group 1 and 49.8 hours in group 2 (P < = .007). Excluding patients who received MRS drug therapy for unrelated conditions, the mean duration of treatment was 19.7 hours in group 1 and 80.7 hours in group 2 (P = .003). Six (50%) of the 12 patients in group 1 and 39 (81%) of the 48 patients in group 2 received MRS drug therapy for MSSA bacteremia (P = .025). Time to initiation of therapy for MRSA bacteremia did not differ between groups.

The use of an assay with rapid results reduced the use of antistaphylococcal therapy among patients who did not have S. aureus bacteremia; it also decreased the use of MRS drug therapy and led to earlier appropriate therapy among patients with MSSA bacteremia.

To determine whether the molecular epidemiological characteristics of methicillin-resistant Staphylococcus aureus (MRSA) had changed in a level III neonatal intensive care unit (NICU).

Retrospective review of medical records.

Level III NICU of a university-affiliated children's hospital in New York, New York.

Case patients were neonates hospitalized in the NICU who were colonized or infected with MRSA.

Rates of colonization and infection with MRSA during the period from 2000 through 2008 were assessed. Staphylococcal chromosomal cassette (SCC) mecA analysis and genotyping for S. aureus encoding protein A (spa) were performed on representative MRSA isolates from each clonal pulsed-field gel electrophoresis pattern.

Endemic MRSA infection and colonization occurred throughout the study period, which was punctuated by 4 epidemiologic investigations during outbreak periods. During the study period, 93 neonates were infected and 167 were colonized with MRSA. Surveillance cultures were performed for 1,336 neonates during outbreak investigations, and 115 (8.6%) neonates had MRSA-positive culture results. During 2001-2004, healthcare-associated MRSA clones, carrying SCC mec type II, predominated. From 2005 on, most MRSA clones were community-associated MRSA with SCC mec type IV, and in 2007, USA300 emerged as the principal clone.

Molecular analysis demonstrated a shift from healthcare-associated MRSA (2001-2004) to community-associated MRSA (2005-2008).

(1) To determine whether rapid screening with polymerase chain reaction (PCR) assays leads to the earlier isolation of patients at risk for methicillin-resistant Staphylococcus aureus (MRSA) colonization, (2) to assess compliance with routine MRSA screening protocols, (3) to confirm the diagnostic accuracy of the Xpert MRSA real-time PCR assay (Cepheid) by comparison with culture, and (4) to compare turnaround times for PCR assay results with those for culture results.

Before-and-after study conducted in a 700-bed acute tertiary care referral hospital. Study periods were (1) a 5-week period before PCR testing began, (2) a 10-week period when the PCR assay was used, and (3) a 5-week period after PCR testing was discontinued.

Among 489 at-risk patients, MRSA was isolated from 20 (33%) of 60 patients during period 1, 77 (22%) of 349 patients during period 2, and 18 (23%) of 80 patients during period 3. Twenty-two (27%) of 82 at-risk patients were not screened during period 1, compared with 40 (10%) of 389 at-risk patients not screened during period 2 (P < .001). More MRSA-positive patients were preemptively isolated during periods 1 and 3 compared with period 2 (34 [24%] of 140 vs 28 [8%] of 389; P < .001); however, more MRSA-positive patients were isolated after notification of MRSA-positive results during period 2 (47 [13%] of 349) compared with periods 1 and 3 (2 [1%] of 140; P < .001). The sensitivity, specificity, positive predictive value, and negative predictive value of the PCR assay were 95%, 97%, 82%, and 99%, respectively. The mean turnaround time from receipt of specimens in the laboratory to PCR assay result was 2.6 hours.

Rapid screening with the Xpert MRSA PCR assay facilitated compliance with screening policies and the earlier isolation of MRSA-positive Patients. Discrepant results confirm that PCR testing should be used as a screening tool rather than as a diagnostic tool.

While the Republic of Georgia has a high prevalence of hepatitis B virus (HBV) infection (3.4% of blood donors tested positive for HBV surface antigen [HBsAg]), relatively few healthcare workers (HCWs) are thought to be immunized.

To measure rates of HBV vaccination coverage and identify predictors of vaccine acceptance among HCWs.

Cross-sectional survey.

A study was conducted among full-time physicians and nurses at 2 large hospitals. Self-administered questionnaires included questions about demographic characteristics, HBV vaccine status, willingness to recommend vaccination to other HCWs, and barriers to vaccination. Laboratory tests were conducted for identification of HBsAg and antibody to hepatitis B core antigen.

A total of 297 (91%) of 325 randomly selected HCWs provided information for the study (124 physicians and 173 nurses). The rate of HBV vaccination coverage was 12%, and 54% of respondents indicated that they would recommend vaccination to other HCWs. Perception of vaccine safety was identified as the most important predictor for acceptance (prevalence ratio [PR] 3.3 [95% confidence ratio {CI}, 1.2-8.9]) and for willingness to recommend HBV vaccination to other HCWs (PR, 5.5 [95% CI, 3.1-9.4]). Vaccinated HCWs were more likely to recommend vaccination to other healthcare personnel (PR, 1.7 [95% CI, 1.5-2.1]), as were those younger than 40 years of age (PR, 6.0 [95% CI, 2.8-12.6]). Multivariate analyses identified 2 additional factors associated with vaccine acceptance and willingness to recommend vaccination: the hospital at which the HCW was employed and the perception of risk of infection for HCWs.

Georgia plans a major HBV vaccination campaign for HCWs in 2009. The campaign's success will depend on addressing vaccine safety concerns identified in this study and educating HCWs about risk factors for infection and benefits of immunization.

Bacteremia is relatively common in patients with skin and skin-structure infection (SSSI) severe enough to require hospitalization. We used selected demographic and clinical characteristics easily assessable at initial evaluation to develop a model for the early identification of patients with SSSI who are at higher risk for bacteremia.

A large database of adults hospitalized with SSSI at 97 hospitals in the United States during the period from 2003 through 2007 and from whom blood samples were obtained for culture at admission.

We compared selected candidate predictor variables for patients shown to have bacteremia and patients with no demonstrated bacteremia. Using stepwise logistic regression to identify independent risk factors for bacteremia, we derived a model by using 75% of a randomly split cohort, converted the model coefficients into a risk score system, and then we validated it by using the remaining 25% of the cohort.

Bacteremia was documented in 1,021 (11.7%) of the 8,747 eligible patients. Independent predictors of bacteremia (P<.001) were infected device or prosthesis, respiratory rate less than 10 or more than 29 breaths per minute, pulse rate less than 49 or more than 125 beats per minute, temperature less than 35.6°C or at least 38.0°C, white blood cell band percentage of 7% or more, white blood cell count greater than 11 x 109/L, healthcare-associated infection, male sex, and older age. The bacteremia rates ranged from 3.7% (lowest decile) to 30.6% (highest decile) (P< .001). The model C statistic was 0.71; the Hosmer-Lemeshow test P value was .36, indicating excellent model calibration.

Using data available at hospital admission, we developed a risk score that differentiated SSSI patients at low risk for bacteremia from patients at high risk. This score may help clinicians identify patients who require more intensive monitoring or antimicrobial regimens appropriate for treating bacteremia.

The International Nosocomial Infection Control Consortium (INICC) was established in 15 developing countries to reduce infection rates in resource-limited hospitals by focusing on education and feedback of outcome surveillance (infection rates) and process surveillance (adherence to infection control measures). We report a time-sequence analysis of the effectiveness of this approach in reducing rates of central line–associated bloodstream infection (CLABSI) and associated deaths in 86 intensive care units with a minimum of 6-month INICC membership.

Pooled CLABSI rates during the first 3 months (baseline) were compared with rates at 6-month intervals during the first 24 months in 53,719 patients (190,905 central line–days). Process surveillance results at baseline were compared with intervention period data.

During the first 6 months, CLABSI incidence decreased by 33% (from 14.5 to 9.7 CLABSIs per 1,000 central line–days). Over the first 24 months there was a cumulative reduction from baseline of 54% (from 16.0 to 7.4 CLABSIs per 1,000 central line–days; relative risk, 0.46 [95% confidence interval, 0.33–0.63]; P <.001). The number of deaths in patients with CLABSI decreased by 58%. During the intervention period, hand hygiene adherence improved from 50% to 60% (P<.001); the percentage of intensive care units that used maximal sterile barriers at insertion increased from 45% to 85% (P < .001), that adopted Chlorhexidine for antisepsis increased from 7% to 27% (P = .018), and that sought to remove unneeded catheters increased from 37% to 83% (P = .004); and the duration of central line placement decreased from 4.1 to 3.5 days (P < .001).

Education, performance feedback, and outcome and process surveillance of CLABSI rates significantly improved infection control adherence, reducing the CLABSI incidence by 54% and the number of CLABSI-associated deaths by 58% in INICC hospitals during the first 2 years.

To compare the surgical site infection (SSI) rate after primary total hip arthroplasty with the SSI rate after revision total hip arthroplasty.

Retrospective cohort study.

Mayo Clinic in Rochester, Minnesota, a referral orthopedic center.

All patients undergoing primary total hip arthroplasty or revision total hip arthroplasty during the period from January 1, 2002, through December 31, 2006.

We obtained data on total hip arthroplasties from a prospectively maintained institutional surgical database. We reviewed data on SSIs collected prospectively as part of routine infection control surveillance, using the criteria of the Centers for Disease Control and Prevention for the definition of an SSI. We used logistic regression analyses to evaluate differences between the SSI rate after primary total hip arthroplasty and the SSI rate after revision total hip arthroplasty.

A total of 5,696 total hip arthroplasties (with type 1 wound classification) were analyzed, of which 1,381 (24%) were revisions. A total of 61 SSIs occurred, resulting in an overall SSI rate of 1.1% for all total hip arthroplasties. When stratified by the National Nosocomial Infection Surveillance (NNIS) risk index, SSI rates were 0.5%, 1.2%, and 1.6% in risk categories 0, 1, and 2, respectively. After controlling for the NNIS risk index, the risk of SSI after revision total hip arthroplasty was twice as high as that after primary total hip arthroplasty (odds ratio, 2.2 [95% confidence interval, 1.3-3.7]). In the analysis restricted to the development of deep incisional or organ space infections, the risk of SSI after revision total hip arthroplasty was nearly 4 times that after primary total hip arthroplasty (odds ratio, 3.9 [95% confidence interval, 2.0-7.6]).

Including revision surgeries in the calculation of SSI rates can result in higher infection rates for institutions that perform a larger number of revisions. Taking NNIS risk indices into account does not eliminate this effect. Differences between primary and revision surgeries should be considered in national standards for the reporting of SSIs.

To explore epidemiological patterns of the incidence of Clostridium difficile infection (CDI) and hospital characteristics associated with increased incidence during nonepidemic and epidemic years.

Retrospective and prospective ecological study.

Eighty-three acute care hospitals participating in CDI surveillance in the province of Quebec, Canada.

A Serfling-type regression model applied to data obtained from an administrative database (1998-2006) and prospective Quebec CDI surveillance (2004-2006) was used to calculate expected CDI baseline incidence and to detect incidence exceeding the defined epidemic threshold at the provincial and hospital level. Multivariable Poisson regression was used to determine hospital characteristics associated with increased incidence during nonepidemic (1998-2001) and epidemic (2003-2005) periods.

During the study period (1998-2006), 4,525,847 discharges, including 45,508 with a CDI in any diagnosis field, were reported by 83 hospitals. During 1998-2001, the average Quebec incidence of CDI was 10,304 cases in 1,775,822 discharges (5.8 cases per 1,000 discharges) and presented a pattern of seasonality, with similar patterns at the hospital level for some hospitals. The Quebec epidemic started in October-November 2002 and peaked in March 2004 at 845 cases in 40,852 discharges (20.7 cases per 1,000 discharges). In multivariable analysis, higher incidence was associated with location in Montreal and surrounding regions, greater hospital size, larger proportion of hospitalized elderly patients, longer length of stay, and greater proportion of comorbidities in patients, whereas teaching profile was associated with decreased incidence during both nonepidemic and epidemic periods. The effect of geographical location on incidence was greater during the epidemic.

Baseline incidence from nonepidemic years and hospital characteristics associated with CDI incidence should be taken into account when estimating the efficacy of interventions.

To assess the prevalence and correlates of compliance and noncompliance with hand hygiene guidelines in hospital care.

A systematic review of studies published before January 1, 2009, on observed or self-reported compliance rates.

Articles on empirical studies written in English and conducted on general patient populations in industrialized countries were included. The results were grouped by type of healthcare worker before and after patient contact. Correlates contributing to compliance were grouped and listed.

We included 96 empirical studies, the majority (n = 65) in intensive care units. In general, the study methods were not very robust and often ill reported. We found an overall median compliance rate of 40%. Unadjusted compliance rates were lower in intensive care units (30%–40%) than in other settings (50%–60%), lower among physicians (32%) than among nurses (48%), and before (21%) rather than after (47%) patient contact. The majority of the time, the situations that were associated with a lower compliance rate were those with a high activity level and/or those in which a physician was involved. The majority of the time, the situations that were associated with a higher compliance rate were those having to do with dirty tasks, the introduction of alcohol-based hand rub or gel, performance feedback, and accessibility of materials. A minority of studies (n = 12) have investigated the behavioral determinants of hand hygiene, of which only 7 report the use of a theoretical framework with inconclusive results.

Noncompliance with hand hygiene guidelines is a universal problem, which calls for standardized measures for research and monitoring. Theoretical models from the behavioral sciences should be used internationally and should be adapted to better explain the complexities of hand hygiene.

To describe an outbreak of infection associated with an infrequently implicated pathogen, Elizabethkingia meningoseptica, in an increasingly prominent setting for health care of severely ill patients, the long-term acute care hospital.

Outbreak investigation.

Long-term acute care hospital with 55 patients, most of whom were mechanically ventilated.

We defined a case as E. meningoseptica isolated from any patient specimen source from December 2007 through April 2008, conducted an investigation of case patients, obtained environmental specimens, and performed microbiologic testing.

Nineteen patients had E. meningoseptica infection, and 8 died. All case patients had been admitted with respiratory failure that required mechanical ventilation. Among the 8 individuals who died, the time from collection of the first specimen positive for E. meningoseptica to death ranged from 6 to 43 days (median, 16 days). Environmental sampling was performed on 106 surfaces; E. meningoseptica was isolated from only one swab. Three related pulsed-field gel electrophoresis patterns were identified in patient isolates; the environmental isolate yielded a fourth, unrelated pattern.

Long-term acute care hospitals with mechanically ventilated patients could serve as an important transmission setting for E. meningoseptica. This multidrug-resistant bacterium could pose additional risk when patients are transferred between long-term acute care hospitals and acute care hospitals.

To characterize the degree of colonization with multidrug-resistant organisms (MDROs) among patients admitted to a long-term acute care hospital.

Ecologie Study.

A 70-bed long-term acute care hospital (a hospital within a hospital) in the greater Chicago area.

As part of an infection control initiative, specimens were collected from all consecutively admitted patients for culture of MDROs within 72 hours of admission. Cultures from July 28, 2005, through November 1, 2008, were analyzed on the basis of the bodily site from which the isolate was recovered and the organisms identified. If MDROs were yielded by culture of specimens that were obtained from 24 hours to 30 days after collection of the patient's original set of specimens, these MDROs were removed from the analysis. In addition, repeat rectal swab samples were collected for culture at 2 weeks after admission for all consecutive patients admitted from January 1 through March 31, 2007.

A total of 1,739 patients with a total of 5,198 specimens met entry criteria. Of the corresponding 5,198 surveillance cultures, 1,580 (30%) were positive for MDROs. Of the 1,739 patients, 947 (54%) had a culture-positive specimen recovered from any site. Vancomycin-resistant Enterococcus was the organism most commonly isolated in cultures of rectal swab samples (in 38% of such cultures) and wounds (in 18% of such cultures). The rate of rectal carriage of vancomycin-resistant Enterococcus increased from 29% in 2005 to 44% in 2008.

Multidrug-resistant (MDR) Acinetobacter baumannii and Pseudomonas aeruginosa have emerged as the causes of nosocomial infections in critically ill patients.

To characterize the incidence of these MDR bacteria over time in the military healthcare system, comparing isolates recovered from overseas combat casualties with isolates recovered from local military and civilian patients.

Retrospective electronic records review of culture and/or susceptibility testing results of patients admitted to a military level I trauma center in San Antonio, Texas, during the period from January 2001 through December 2008. Multidrug resistance was defined as the first isolated organism resistant to 3 or more classes of antimicrobial agents.

Over time, the percentage of MDR A. baumannii isolates increased from 4% to 55%, whereas the percentage of MDR P. aeruginosa isolates increased from 2% to 8%. Respiratory tract specimens had a higher percentage of MDR A. baumannii isolates (49%), compared with specimens obtained from blood (30%), wound sites (24%), or urine (19%). No difference in the percentages of MDR P. aeruginosa isolates was observed with regard to source of specimen. The percentage of MDR A. baumannii isolates recovered was higher among patients who had been deployed overseas (52%) than among local patients (20%). When isolates recovered from patients in the burn intensive care unit (53% of MDR A. baumannii isolates) were removed from analysis, the percentage of MDR A. baumannii isolates decreased from 38% to 30% while the percentage of MDR P. aeruginosa isolates remained unaffected.

The percentage of MDR A. baumannii isolates increased in this facility among combat casualties and among local patients, which indicates nosocomial transmission; however, there was no significant increase in the percentage of MDR P. aeruginosa isolates. Isolated changes in the MDR pathogens within a facility can occur. Possible interventions to limit the spread of these organisms could include implementing aggressive infection control practices, controlling antibiotic use, and using active culture surveillance.

To characterize the temporal progression of the monthly incidence of Clostridium difficile infections (CDIs) and to determine whether the incidence of CDI is related to the incidence of seasonal influenza.

A retrospective study of patients in the Nationwide Inpatient Sample during the period from 1998 through 2005.

We identified all hospitalizations with a primary or secondary diagnosis of CDI with use of International Classification of Diseases, 9th Revision, Clinical Modification codes, and we did the same for influenza. The incidence of CDI was modeled as an autoregression about a linear trend. To investigate the association of CDI with influenza, we compared national and regional CDI and influenza series data and calculated cross-correlation functions with data that had been prewhitened (filtered to remove temporal patterns common to both series). To estimate the burden of seasonal CDI, we developed a proportional measure of seasonal CDI.

Time-series analysis of the monthly number of CDI cases reveals a distinct positive linear trend and a clear pattern of seasonal variation (R2 = 0.98). The cross-correlation functions indicate that influenza activity precedes CDI activity on both a national and regional basis. The average burden of seasonal (ie, winter) CDI is 23%.

The epidemiologic characteristics of CDI follow a pattern that is seasonal and associated with influenza, which is likely due to antimicrobial use during influenza seasons. Approximately 23% of average monthly CDI during the peak 3 winter months could be eliminated if CDI remained at summer levels.