To study an outbreak of Mycobacterium mucogenicum bloodstream infections in an outpatient setting.

Outbreak investigation and retrospective chart review.

University outpatient clinic.

Patients whose blood cultures tested positive for M. mucogenicum in May or June 2008.

An outbreak investigation and a review of infection control practices were conducted. During the process, environmental culture samples were obtained. Isolates from patients and the environment were genotyped with the DiversiLab typing system to identify the source. Chart reviews were conducted to study the management and outcomes of the patients.

Four patients with sickle cell disease and implanted ports followed in the same hematology outpatient clinic developed blood cultures positive for M. mucogenicum. A nurse in the clinic had prepared intravenous port flushes on the sink counter, using a saline bag that was hanging over the sink throughout the shift. None of the environmental cultures grew M. mucogenicum except for the tap water from 2 rooms, 1 of which had a faucet aerator. The 4 patient isolates and the tap water isolate from the room with the aerator were found to have greater than 98.5% similarity. The subcutaneous ports were removed, and patients cleared their infections after a course of antibiotic therapy.

The source of the M. mucogenicum bacteremia outbreak was identified by genotyping analysis as the clinic tap water supply. The preparation of intravenous medications near the sink was likely an important factor in transmission, along with the presence of a faucet aerator.

To describe the epidemiology of surgical-site infections (SSIs) in community hospitals and to explore the impact of depth of SSI, healthcare location at the time of diagnosis, and variations in surveillance practices on the overall rate of SSI.

Retrospective cohort study.

Thirty-seven community hospitals in the southeastern United States.

Consecutive sample of patients undergoing surgical procedures between July 1, 2007, and December 31, 2008.

ANOVA was used to compare rates of SSIs, and the F test was used to compare the distribution of rates of SSIs. Wilcoxon rank-sum was used to test for differences in performance rankings of hospitals.

Following 177,706 surgical procedures, 1,919 SSIs were identified (incidence, 1.08 per 100 procedures). Sixty-four percent (1,223 of 1,919) of these were identified as complex SSIs; 87% of the complex SSIs were diagnosed in inpatient settings. The median proportion of superficial-incisional SSIs was 37% (interquartile range, 29.6%–49.5%). Postdischarge SSI surveillance was variable, with 58% of responding hospitals using surgeon letters. As reporting focus was narrowed from all SSIs to complex SSIs (incidence, 0.69 per 100 procedures) and, finally, to complex SSIs diagnosed in the inpatient setting (incidence, 0.51 per 100 procedures), variance in rates changed significantly (P = .02). Performance ranking of individual hospitals, based on rates of SSIs, differed significandy, depending on the reporting method utilized (P = .0006).

Inconsistent reporting mediods focused on variable depths of infection and healthcare location at time of diagnosis significandy impact rates of SSI, distribution of rates of SSI, and hospital comparative-performance rankings. We believe that public reporting of SSI rates should be limited to complex SSIs diagnosed in the inpatient setting.

Infect Control Hosp Epidemiol 2012;33(3):276-282

To compare the microbiological efficacy of hydrogen peroxide vapor (HPV) and ultraviolet radiation (UVC) for room decontamination.

Prospective observational study.

500-bed teaching hospital.

HPV and UVC processes were performed in 15 patient rooms. Five high-touch sites were sampled before and after the processes and aerobic colony counts (ACCs) were determined. Carrier disks with ~106Clostridium difficile (CD) spores and biological indicators (BIs) with 104 and 106Geobacillus stearothermophilus spores were placed in 5 sites before decontamination. After decontamination, CD log reductions were determined and BIs were recorded as growth or no growth.

93% of ACC samples that had growth before HPV did not have growth after HPV, whereas 52% of sites that had growth before UVC did not have growth after UVC (P < .0001). The mean CD log reduction was >6 for HPV and ~2 for UVC. After HPV 100% of the 104 BIs did not grow, and 22% did not grow after UVC, with a range of 7%–53% for the 5 sites. For the 106 BIs, 99% did not grow after HPV and 0% did not grow after UVC. Sites out of direct line of sight were significantly more likely to show growth after UVC than after HPV. Mean cycle time was 153 (range, 140–177) min for HPV and 73 (range, 39–100) min for UVC (P < .0001).

Both HPV and UVC reduce bacterial contamination, including spores, in patient rooms, but HPV is significantly more effective. UVC is significantly less effective for sites that are out of direct line of sight.

Assessing the relative success of serial strategies for increasing healthcare personnel (HCP) influenza vaccination rates is important to guide hospital policies to increase vaccine uptake.

To evaluate serial campaigns that include a mandatory HCP vaccination policy and to describe HCP attitudes toward vaccination and reasons for declination.

Retrospective cohort study.

We assessed the impact of serial vaccination campaigns on the proportions of HCP who received influenza vaccination during die 2006–2011 influenza seasons. In addition, declination data over these 5 seasons and a 2007 survey of HCP attitudes toward vaccination were collected.

HCP influenza vaccination rates increased from 44.0% (2,863 of 6,510 HCP) to 62.9% (4,037 of 6,414 HCP) after institution of mobile carts, mandatory declination, and peer-to-peer vaccination efforts. Despite maximal attempts to improve accessibility and convenience, 27.2% (66 of 243) of die surveyed HCP were unwilling to wait more than 10 minutes for a free influenza vaccination, and 23.3% (55 of 236) would be indifferent if they were unable to be vaccinated. In this context, institution of a mandatory vaccination campaign requiring unvaccinated HCP to mask during the influenza season increased rates of compliance to over 90% and markedly reduced the proportion of HCP who declined vaccination as a result of preference.

A mandatory influenza vaccination program for HCP was essential to achieving high vaccination rates, despite years of intensive vaccination campaigns focused on increasing accessibility and convenience. Mandatory vaccination policies appear to successfully capture a large portion of HCP who are not opposed to receipt of die vaccine but who have not made vaccination a priority.

Infect Control Hosp Epidemiol 2012;33(1):63-70

To determine the frequency of false-positive Clostridium difficile toxin enzyme immunoassay (EIA) results in hospitalized children and to examine potential reasons for this false positivity.

Nested case-control.

Two tertiary care pediatric hospitals.

As part of a natural history study, prospectively collected EIA-positive stools were cultured for toxigenic C. difficile, and characteristics of children with false-positive and true-positive EIA results were compared. EIA-positive/culture-negative samples were recultured after dilution and enrichment steps, were evaluated for presence of the tcdB gene by polymerase chain reaction (PCR), and were further cultured for Clostridium sordellii, a cause of false-positive EIA toxin assays.

Of 112 EIA-positive stools cultured, 72 grew toxigenic C. difficile and 40 did not, indicating a positive predictive value of 64% in this population. The estimated prevalence of C. difficile infection (CDI) in the study sites among children tested for this pathogen was 5%–7%. Children with false-positive EIA results were significantly younger than those with true-positive tests but did not differ in other characteristics. No false-positive specimens yielded C. difficile when cultured after enrichment or serial dilution, 1 specimen was positive for tcdB by PCR, and none grew C. sordellii.

Approximately one-third of EIA tests used to evaluate pediatric inpatients for CDI were falsely positive. This finding was likely due to the low prevalence of CDI in pediatric hospitals, which diminishes the test's positive predictive value. These data raise concerns about the use of EIA assays to diagnosis CDI in children.

Infect Control Hosp Epidemiol 2012;33(2):175-179

To evaluate the clinical effectiveness of preoperative skin antiseptic preparations and application techniques for the prevention of surgical site infections (SSIs).

Systematic review of the literature using Medline, EMBASE, and other databases, for the period January 2001 to June 2011.

Comparative studies (including randomized and nonrandomized trials) of preoperative skin antisepsis preparations and application techniques were included. Two researchers reviewed each study and extracted data using standardized tables developed before the study. Studies were reviewed for their methodological quality and clinical findings.

Twenty studies (n = 9,520 patients) were included in the review. The results indicated that presurgical antiseptic showering is effective for reducing skin flora and may reduce SSI rates. Given the heterogeneity of the studies and the results, conclusions about which antiseptic is more effective at reducing SSIs cannot be drawn.

The evidence suggests that preoperative antiseptic showers reduce bacterial colonization and may be effective at preventing SSIs. The antiseptic application method is inconsequential, and data are lacking to suggest which antiseptic solution is the most effective. Disinfectant products are often mixed with alcohol or water, which makes it difficult to form overall conclusions regarding an active ingredient. Large, well-conducted randomized controlled trials with consistent protocols comparing agents in the same bases are needed to provide unequivocal evidence on the effectiveness of one antiseptic preparation over another for the prevention of SSIs.

Vancomycin-resistant enterococci (VRE) have become a public health concern with implications for patient mortality and costs. Hospital antibiotic usage may impact VRE incidence, but the relationship is poorly understood. Animal investigations suggest that ceftriaxone may be associated with VRE proliferation. We measured antimicrobial usage and VRE bloodstream infection (VRE-BSI) incidence to test our hypothesis that increased ceftriaxone usage would be associated with a higher incidence of VRE-BSI.

Retrospective cohort study.

University of Alabama at Birmingham Medical Center, a 900-bed urban tertiary care hospital.

All patients admitted during the study period contributed data.

We conducted a retrospective analysis of antimicrobial usage and VRE-BSI from 2005 to 2008 (43 months). Antimicrobial usage was quantified as days of therapy (DOTs) per 1,000 patient-days. VRE-BSI incidence was calculated as cases per 1,000 patient-days. Negative binomial regression with adjustment for correlation between consecutive observations was used to measure the association between antimicrobial usage and VRE-BSI incidence at the hospital- and care-unit levels.

VRE-BSI incidence increased from 0.06 to 0.17 infections per 1,000 patient-days. Hospital VRE-BSI incidence was associated with prior-month ceftriaxone DOTs (incidence rate ratio, 1.38 per 10 DOTs; P = .005). After controlling for ceftriaxone, prior-month cephalosporin usage (class) was not predictive of VRE-BSI (P = .70). Similarly, prior-month usage of piperacillin-tazobactam, ceftazidime, cefepime, cefazolin, or vancomycin was not predictive of VRE-BSI when considered individually (P ≥ .4 for all comparisons). The final model suggests that type of intensive care unit was related to VRE-BSI incidence.

Ceftriaxone usage in the prior month, but not cephalosporin (class) or vancomycin usage, was related to VRE-BSI incidence. These findings suggest that an antimicrobial stewardship program that limits ceftriaxone may reduce nosocomial VRE-BSI incidence.

Healthcare providers need a better empiric antibiotic prescribing aid than the traditional antibiogram, which supplies no information on the relative frequency of organisms recovered in a given infection and which is uninformative in situations where multiple antimicrobials are used or multiple organisms are anticipated. We aimed to develop and demonstrate a novel empiric prescribing decision aid.

This is a demonstration involving more than 9,000 unique encounters for abdominal-biliary infection (ABI) and urinary tract infection (UTI) to a large healthcare system with a fully integrated electronic health record (EHR).

We developed a novel method of displaying microbiology data called the weighted-incidence syndromic combination antibiogram (WISCA) for 2 clinical syndromes, ABI and UTI. The WISCA combines simple diagnosis and microbiology data from the EHR to (1) classify patients by syndrome and (2) determine, for each patient with a given syndrome, whether a given regimen (1 or more agents) would have covered all the organisms recovered for their infection. This allows data to be presented such that clinicians can see the probability that a particular regimen will cover a particular infection rather than the probability that a single drug will cover a single organism.

There were 997 encounters for ABI and 8,232 for UTI. A WISCA was created for each syndrome and compared with a traditional antibiogram for the same period.

Novel approaches to data compilation and display can overcome limitations to the utility of the traditional antibiogram in helping providers choose empiric antibiotics.

To determine healthcare-associated infection (HAI) prevalence in 9 hospitals in Jacksonville, Florida; to evaluate the performance of proxy indicators for HAIs; and to refine methodology in preparation for a multistate survey.

Point prevalence survey.

Acute care inpatients of any age.

HAIs were defined using National Healthcare Safety Network criteria. In each facility a trained primary team (PT) of infection prevention (IP) staff performed the survey on 1 day, reviewing records and collecting data on a random sample of inpatients. PTs assessed patients with one or more proxy indicators (abnormal white blood cell count, abnormal temperature, or antimicrobial therapy) for the presence of HAIs. An external IP expert team collected data from a subset of patient records reviewed by PTs to assess proxy indicator performance and PT data collection.

Of 851 patients surveyed by PTs, 51 had one or more HAIs (6.0%; 95% confidence interval, 4.5%–7.7%). Surgical site infections (n = 18), urinary tract infections (n = 9), pneumonia (n = 9), and bloodstream infections (n = 8) accounted for 75.8% of 58 HAIs detected by PTs. Staphylococcus aureus was the most common pathogen, causing 9 HAIs (15.5%). Antimicrobial therapy was the most sensitive proxy indicator, identifying 95.5% of patients with HAIs.

HAI prevalence in this pilot was similar to that reported in the 1970s by the Centers for Disease Control and Prevention's Study on the Efficacy of Nosocomial Infection Control. Antimicrobial therapy was a sensitive screening variable with which to identify those patients at higher risk for infection and reduce data collection burden. Additional work is needed on validation and feasibility to extend this methodology to a national scale.

Infect Control Hosp Epidemiol 2012;33(3):283-291

To describe trends in hospitalizations with community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection in New York City over 10 years and to explore the demographics and comorbidities of patients hospitalized with CA-MRSA infections.

Retrospective analysis of hospital discharges from New York State's Statewide Planning and Research Cooperative System database from 1997 to 2006.

All patients greater than 1 year of age admitted to New York hospitals with diagnosis codes indicating MRSA who met the criteria for CA-MRSA on the basis of admission information and comorbidities.

We determined hospitalization rates and compared demographics and comorbidities of patients hospitalized with CA-MRSA versus those hospitalized with all other non-MRSA diagnoses by multivariable logistic regression.

Of 18,226 hospitalizations with an MRSA diagnosis over 10 years, 3,579 (20%) were classified as community-associated. The CA-MRSA hospitalization rate increased from 1.47 to 10.65 per 100,000 people overall from 1997 to 2006. Relative to non-MRSA hospitalizations, men, children, Bronx and Manhattan residents, the homeless, patients with human immunodeficiency virus (HIV) infection, and persons with diabetes had higher adjusted odds of CA-MRSA hospitalization.

The CA-MRSA hospitalization rate appeared to increase between 1997 and 2006 in New York City, with residents of the Bronx and Manhattan, men, and persons with HIV infection or diabetes at increased odds of hospitalization with CA-MRSA. Further studies are needed to explore how changes in MRSA incidence, access to care, and other factors may have impacted these rates.