Information on the risk of methicillin-resistant Staphylococcus aureus (MRSA) infection transmission in dental healthcare settings was incomplete only few years ago; therefore, MRSA infection control guidelines were necessarily based on data extrapolated from other fields. Recently, publication of specific studies have made it possible to review such risk.

Studies of MRSA infection in dentistry were searched for using EMBASE, MEDLINE, and Google and were allocated into the following sections: (1) direct evidence: documented cases of MRSA transmission in dentistry; (2) indirect evidence: carriage rates among dental healthcare providers (DHCPs) and patients (high carriage rates suggest that transmission is likely); (3) speculative evidence: MRSA occurrence in the dental environment (high environmental contamination probably increases the risk of infection); and (4) speculative evidence: MRSA carriage in human dental plaque and saliva (oral carriers may spread MRSA in the environment during dental therapy, with consequent environmental contamination and probable increased risk of infection).

Our findings were as follows. First, transmission has been ascertained during surgical interventions, particularly in surgical units and among head and neck cancer patients. Second, carriage rates among DHCPs were lower than those among other healthcare workers. Carriage rates among adult patients were low, whereas among pedodontic and special care patients rates were higher than those in the general population. Third, MRSA has been detected in the environment of emergency and surgical units and in dental hospitals. Some individuals in poor general condition were oral MRSA carriers.

The occupational risk of MRSA infection among DHCPs is minimal. Among special patients (eg, special care, hospitalized and cancer patients) the risk of infection is high, whereas among the remaining patients undergoing conventional therapy such risk is probably low.

To determine whether a mandatory seasonal influenza vaccination program will increase vaccination rates among healthcare personnel (HCP) and affiliated physicians.

MedStar Health is a not-for-profit regional healthcare organization that includes 9 hospitals with approximately 25,000 HCP and approximately 4,000 affiliated physicians. HCP describes any person employed by MedStar Health.

With previous vaccination rates parallel to reported national rates of 54% among HCP, MedStar Health introduced a mandatory seasonal influenza vaccination program promulgated during the 2009–2010 influenza season. HCP and affiliated physicians were given an opportunity to apply for medical or religious exemptions. Noncompliant HCP were terminated. Noncompliant physicians had their privileges administratively suspended for the influenza season.

HCP compliance (vaccinated and exempt) was 99.9%. The influenza vaccination rate among HCP was 98.5%. There were 338 approved medical exemptions and 18 approved religious exemptions. Only 0.01% of HCP (9 full-time, 2 part-time, and 17 per diem employees) were terminated. Overall, 93% of the affiliated physicians were vaccinated; 7 religious and 99 medical exemptions were granted. In total, 149 physicians (4%) had their admitting privileges suspended during the influenza season.

A mandatory influenza vaccination program achieves high rates of vaccination among HCP and affiliated physicians.

Describe the clinical and molecular epidemiology of incident Clostridium difficile infection (CDI) cases in Chicago area acute healthcare facilities (HCFs).

Laboratory, clinical, and epidemiologic information was collected for patients with incident CDI who were admitted to acute HCFs in February 2009. Stool cultures and restriction endonuclease analysis typing of the recovered C. difficile isolates was performed.

Two hundred sixty-three patients from 25 acute HCFs.

Acute HCF rates ranged from 2 to 7 patients with CDI per 10,000 patient-days. The crude mortality rate was 8%, with 20 deaths occurring in patients with CDI. Forty-two (16%) patients had complications from CDI, including 4 patients who required partial, subtotal, or total colectomy, 3 of whom died. C. difficile was isolated and typed from 129 of 178 available stool specimens. The BI strain was identified in 79 (61%) isolates. Of patients discharged to long-term care who had their isolate typed, 36 (67%) had BI-associated CDI.

Severe disease was common and crude mortality was substantial among patients with CDI in Chicago area acute HCFs in February 2009. The outbreak-associated BI strain was the predominant endemic strain identified, accounting for nearly two-thirds of cases. Focal HCF outbreaks were not reported, despite the presence of the BI strain. Transfer of patients between acute and long-term HCFs may have contributed to the high incidence of BI cases in this investigation.

To determine whether preoperative nasal methicillin-resistant Staphylococcus aureus (MRSA) carriage is a significant predictor of postoperative infections, after accounting for surgical infection risk and surgical prophylaxis.

Retrospective cohort study.

Veterans Affairs (VA) Boston patients who had nasal MRSA polymerase chain reaction screening performed in the 31 days before clean or clean contaminated surgery in 2008–2009.

Postoperative MRSA clinical cultures and infections, total surgical site infections (SSIs), and surgical prophylaxis data were abstracted from administrative databases. MRSA infections were confirmed via chart review. Multivariate analysis of risk factors for each outcome was conducted using Poisson regression. SSI risk index was calculated for a subset of 1,551 patients assessed by the VA National Surgical Quality Improvement Program.

Among 4,238 eligible patients, 279 (6.6%) were positive for preoperative nasal MRSA. Postoperative MRSA clinical cultures and infections, including MRSA SSIs, were each significantly increased in patients with preoperative nasal MRSA. After adjustment for surgery type, vancomycin prophylaxis, chlorhexidine/alcohol surgical skin preparation, and SSI risk index, preoperative nasal MRSA remained significantly associated with postoperative MRSA cultures (relative risk [RR], 8.81; 95% confidence interval [CI], 3.01–25.82) and infections (RR, 8.46; 95% CI, 1.70–42.04). Vancomycin prophylaxis was associated with an increased risk of total SSI in those negative for nasal MRSA (RR, 4.34; 95% CI, 2.19–8.57) but not in patients positive for nasal MRSA.

In our population, preoperative nasal MRSA colonization was independently associated with MRSA clinical cultures and infections in the postoperative period. Vancomycin prophylaxis increased the risk of total SSI in nasal MRSA-negative patients.

To outline methods for deriving and validating intensive care unit (ICU) antimicrobial utilization (AU) measures from computerized data and to describe programming problems that emerged.

Retrospective evaluation of computerized pharmacy and administrative data.

ICUs from 4 academic medical centers over 36 months.

Investigators separately developed and validated programming code to report AU measures in selected ICUs. Use of antibacterial and antifungal drugs for systemic administration was categorized and expressed as antimicrobial-days (each day that each antimicrobial drug was given to each patient) and patient-days receiving antimicrobials (each day that any antimicrobial drug was given to each patient). Monthly rates were compiled and analyzed centrally, with ICU patient-days as the denominator. Results were validated against data collected from manual review of medical records. Frequent discussion among investigators aided identification and correction of programming problems.

AU data were successfully programmed though a reiterative process of computer code revision. After identifying and resolving major programming errors, comparison of computerized patient-level data with data collected by manual review of medical records revealed discrepancies in antimicrobial-days and patient-days receiving antimicrobials that ranged from less than 1% to 17.7%. The hospital from which numerator data were derived from electronic records of medication administration had the least discrepant results.

Computerized AU measures can be derived feasibly, but threats to validity must be sought out and corrected. The magnitude of discrepancies between computerized AU data and a gold standard based on manual review of medical records varies, with electronic records of medication administration providing maximal accuracy.

To evaluate the effect of oral hygiene with 0.12% Chlorhexidine gluconate on the incidence of nosocomial pneumonia and ventilator-associated pneumonia (VAP) in children undergoing cardiac surgery.

Prospective, randomized, double-blind, placebo-controlled trial.

Pediatric intensive care unit (PICU) at a tertiary care hospital.

One hundred sixty children undergoing surgery for congenital heart disease, randomized into 2 groups: Chlorhexidine (n = 87) and control (n = 73).

Oral hygiene with 0.12% Chlorhexidine gluconate or placebo preoperatively and twice a day postoperatively until PICU discharge or death.

Patients in experimental and control groups had similar ages (median, 12.2 vs 10.8 months; P = .72) and risk adjustment for congenital heart surgery 1 score distribution (66% in category 1 or 2 in both groups; P = .17). The incidence of nosocomial pneumonia was 29.8% versus 24.6% (P = .46) and the incidence of VAP was 18.3% versus 15% (P = .57) in the Chlorhexidine and the control group, respectively. There was no difference in intubation time (P = .34), need for reintubation (P = .37), time interval between hospitalization and nosocomial pneumonia diagnosis (P = .63), time interval between surgery and nosocomial pneumonia diagnosis (P = .10), and time on antibiotics (P = .77) and vasoactive drugs (P = .16) between groups. Median length of PICU stay (3 vs 4 days; P = .53), median length of hospital stay (12 vs 11 days; P = .67), and 28-day mortality (5.7% vs 6.8%; P = .77) were also similar in the Chlorhexidine and the control group.

Oral hygiene with 0.12% Chlorhexidine gluconate did not reduce the incidence of nosocomial pneumonia and VAP in children undergoing cardiac surgery.

ClinicalTrials.gov identifier: NCT00829842.

To conduct an exploratory study to evaluate the clinical effectiveness and cost benefit of universal versus targeted screening for methicillin-resistant Staphylococcus aureus (MRSA) to prevent hospital-acquired MRSA infections.

Prospective, interventional study, using a case-control design, difference-in-differences, and cost-benefit analyses.

Two community hospitals in Wisconsin.

Consecutive sample of 15,049 adult admissions from April 2009 to July 2010.

MRSA surveillance performed by polymerase chain reaction (PCR) on samples collected from all adult patients (aged over 18 years) within 30 days before or upon an admission to the hospital. During a 9-month baseline period, targeted screening was conducted at both hospitals. During the 5-month intervention period, all patients admitted to the intervention hospital were screened for MRSA. Infection control measures were consistent at both hospitals.

Universal screening was associated with an increase in admission screening of 43.58 percentage points (P<.01), an increase in MRSA detection of 2.95 percentage points (P<.01), and a small, nonsignificant decline in hospital-acquired MRSA infections of 0.12 percentage points (P = .34). The benefit-to-cost ratio was 0.50, indicating that for every dollar spent on universal versus targeted screening, only $0.50 is recovered in avoided costs of hospital-acquired MRSA infection.

Compared with targeted screening, universal screening increased the rate of detection of MRSA upon hospital admission but did not significantly reduce the rate of hospital-acquired MRSA infection. Universal screening was associated with higher costs of care and was not cost beneficial.

To analyze a decade of hospital staff and student exposures to blood and body fluids (BBF) and to identify risk factors relevant to prevention strategies.

Retrospective review of a 1999–2008 data set of BBF exposures. The data, maintained by occupational health staff, detailed the type of exposure, the setting in which the exposure occurred, and the occupational group of the BBF-exposed personnel.

Washington DC Veterans Affairs Medical Center (VA-DC), an inner-city tertiary care hospital.

All healthcare workers and staff at the VA-DC.

Review of database.

A review of 10 years of data revealed 564 occupational exposures to BBF, of which 66% were caused by needlesticks and 20% were caused by sharp objects. Exposures occurred most often in the acute care setting (which accounted for 39% of exposures) and the operating room (which accounted for 22%). There was a mean of 4.9 exposures per 10,000 acute care patient-days, 0.5 exposures per 10,000 long-term care patient-days, and 0.35 exposures per 10,000 outpatient visits. Housestaff accounted for the highest number of all exposures (196 [35%]). There were, on average, 15.2 exposures per 100 housestaff full-time equivalents. An average of only 1 exposure per year occurred in the hemodialysis center.

Occupational exposures to BBF remain common, but rates vary widely by setting and occupational group. Overall rates are steady across a decade, despite the use of various antiexposure devices and provider education programs. Targeting occupational groups and hospital settings that have been shown to have the highest risk rates should become foundational to future preventative strategies.

Endonasal endoscopic skull base surgery (ESBS) is perceived as having a high risk of infection because it is performed through the sinuses, which are not sterile.

To identify the bacteriological characteristics, incidence, mortality, and risk factors for intracranial infection after ESBS.

A retrospective analysis of the first 1,000 ESBS procedures performed at the University of Pittsburgh Medical Center from 1998 to 2008.

In 18 cases (1.8%), the patient developed meningitis. In 2 cases, the patient died within 2 months after surgery, of noninfectious causes. In 11 cases, cerebrospinal fluid (CSF) cultures had positive results. There were no predominant pathogens. Male sex (odds ratio [OR], 3.97 [95% confidence interval {CI}, 1.21-13.03]; P = .02), history of a craniotomy or endonasal surgery (OR, 4.77 [95% CI, 1.68-13.56];P = .003), surgerywith higher levels of complexity (OR, 6.60 [95% CI, 1.77-24.70];P = .005), the presence of an external ventricular drain or ventriculoperitoneal shunt at the time of surgery (OR, 6.38 [95% CI, 1.07-38.09]; P = .04), and postoperative CSF leak (OR, 12.99 [95% CI, 4.24-39.82]; P<.001) were risk factors for infection.

The incidence of infection of 1.8% in ESBS is comparable to that in open craniotomy. The most important risk factor was a postoperative CSF leak. All patients recovered from their infection.

To use clinical vignettes to understand antimicrobial prescribing practices in neonatal intensive care units (NICUs).

Vignette-based survey.

Four tertiary care NICUs.

Antibiotic prescribers in NICUs.

Clinicians from 4 tertiary care NICUs completed an anonymous survey containing 12 vignettes that described empiric, targeted, or prophylactic antibiotic use. Responses were compared with Centers for Disease Control and Prevention guidelines for appropriate use.

Overall, 161 (59% of 271 eligible respondents) completed the survey, 37% of whom had worked in NICUs for 7 or more years. Respondents were more likely to appropriately identify use of targeted therapy for methicillin-susceptible Staphylococcus aureus, that is, use of oxacillin rather than vancomycin, than for Escherichia coli, that is, use of first-generation rather than third-generation cephalosporin, (P < .01). Increased experience significantly predicted appropriate prescribing (P = .02 ). The proportion of respondents choosing appropriate duration of postsurgical prophylaxis (P < .01) and treatment for necrotizing enterocolitis differed by study site (P = .03).

The survey provides insight into antibiotic prescribing practices and informs the development of future antibiotic stewardship interventions for NICUs.

Prepared ready-to-eat salads and ready-to-eat delicatessen-style meats present a high risk for Listeria contamination. Because no foodborne illness risk management guidelines exist specifically for US hospitals, a survey of New York City (NYC) hospitals was conducted to characterize policies and practices after a listeriosis outbreak occurred in a NYC hospital.

From August through October 2008, a listeriosis outbreak in a NYC hospital was investigated. From February through April 2009, NYC's 61 acute-care hospitals were asked to participate in a telephone survey regarding food safety practices and policies, specifically service of high-risk foods to patients at increased risk for listeriosis.

Five patients with medical conditions that put them at high risk for listeriosis had laboratory-confirmed Listeria monocytogenes infection. The Listeria outbreak strain was isolated from tuna salad prepared in the hospital. Fifty-four (89%) of 61 hospitals responded to the survey. Overall, 81% of respondents reported serving ready-to-eat deli meats to patients, and 100% reported serving prepared ready-to-eat salads. Pregnant women, patients receiving immunosuppressive drugs, and patients undergoing chemotherapy were served ready-to-eat deli meats at 77%, 59%, and 49% of hospitals, respectively, and were served prepared ready-to-eat salads at 94%, 89%, and 73% of hospitals, respectively. Only 4 (25%) of 16 respondents reported having a policy that ready-to-eat deli meats must be heated until steaming hot before serving.

Despite the potential for severe outcomes of Listeria infection among hospitalized patients, the majority of NYC hospitals had no food preparation policies to minimize risk. Hospitals should implement policies to avoid serving high-risk foods to patients at risk for listeriosis.

To describe outbreaks of nosocomial influenza infection with molecular methods and to elucidate the viral linkages among outbreak case patients including both inpatients and healthcare workers (HCWs).

A 180-bed acute and long-term care hospital in Japan.

Retrospective observational study of nosocomial outbreaks of infection with influenza A/H3N2. Together with information about onset dates and vaccination history, we obtained nasopharyngeal swab samples from individuals with cases of influenza or influenzalike illness (ILI). The hemagglutinin genes of the recovered viruses were sequenced and compared, along with those of community-circulating strains, for similarity by phylogenetic tree analysis.

The outbreaks occurred from February 26 through April 3, 2007, during the 2006–2007 epidemic season, and they involved 11 patients and 13 HCWs. The 2 outbreaks involved 2 different genotypes of influenza A/H3N2 viruses. These virus variants were closely related to the influenza strains that were circulating in the community during the same epidemic season.

This study showed the dissemination of highly homologous influenza virus variants among inpatients and HCWs within a short period, as a result of nosocomial transmission. These strains were also similar to influenza strains that were circulating in the community.

Colonization pressure is an important infection control metric. The aim of this study was to describe the definition and measurement of and adjustment for colonization pressure in nosocomial-acquisition risk factor studies of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and Clostridium difficile.

We performed a computerized search of studies of nosocomial MRSA, VRE, and C. difficile acquisition published before July 1, 2009, through MEDLINE. Studies were included if a study outcome was MRSA, VRE, or C. difficile acquisition; the authors identified risk factors associated with MRSA, VRE, or C. difficile acquisition; and the study measured colonization pressure.

The initial MEDLINE search yielded 505 articles. Sixty-six of these were identified as studies of nosocomial MRSA, VRE, or C. difficile acquisition; of these, 18 (27%) measured colonization pressure and were included in the final review. The definition of colonization pressure varied considerably between studies: the proportion of MRSA- or VRE-positive patients (5 studies), the proportion of MRSA- or VRE-positive patient-days (6 studies), or the total or mean number of MRSA-, VRE-, or C. difficile-positive patients or patient-days (7 studies) in the unit over periods of varying length. In 10 of 13 studies, colonization pressure was independently associated with MRSA, VRE, or C. difficile acquisition.

There is a need for a simple and consistent method to quantify colonization pressure in both research and routine clinical care to accurately assess the effect of colonization pressure on cross-transmission of antibiotic-resistant bacteria.