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Background: Limited data are available on the effectiveness of 13-valent pneumococcal conjugate vaccine (PCV13) in resource-poor settings and PCV naïve populations. The Dominican Republic introduced PCV13 in September 2013 using a 2 + 1 schedule (2, 4, and 12 months) without a catch-up campaign. We evaluated PCV13 effectiveness against vaccine-type (VT) invasive pneumococcal disease (IPD) among children in the Dominican Republic., Methods: We conducted a matched case-control study. A case-patient was defined as VT-IPD identified by culture or polymerase chain reaction (PCR) from a normally sterile-site in a hospitalized child who was age-eligible to have received ≥1 PCV13 dose. Four age- and neighborhood-matched controls were enrolled for each case-patient. We collected demographic, vaccination history, and risk factor data. Conditional logistic regression was performed. Vaccine effectiveness was calculated as (1- adjusted matched odds ratio for vaccination) X 100%., Results: We enrolled 39 case-patients and 149 matched-controls. Most case-patients had pneumonia with pleural effusion (64%), followed by meningitis (28%) and septicemia (13%). The most common pneumococcal serotypes identified included 14 (18%), 3 (13%), 19A (10%), and 1 (8%). Fewer case-patients had ≥1 PCV13 dose as compared to controls (61.5% vs. 80.0%; p = 0.006). Adjusting for malnutrition and socioeconomic status, VE of ≥1 PCV13 dose compared to no doses was 67.2% (95% CI: 2.3% to 90.0%). Only 44% of controls were up-to-date for PCV13, suggesting low vaccine coverage in the population., Conclusions: We found that PCV13 provided individual protection against VT-IPD in this resource-poor setting with a PCV-naïve population, despite low PCV13 coverage. Expanding vaccination coverage might increase PCV13 impact.

Bacterial meningitis is a severe, acute infection of the fluid surrounding the brain and spinal cord that can rapidly lead to death. Even with recommended antibiotic treatment, up to 25% of infected persons in Africa might experience neurologic sequelae (1). Three regions in northern Ghana (Upper East, Northern, and Upper West), located in the sub-Saharan "meningitis belt" that extends from Senegal to Ethiopia, experienced periodic outbreaks of meningitis before introduction of serogroup A meningococcal conjugate vaccine (MenAfriVac) in 2012 (2,3). During December 9, 2015-February 16, 2016, a total of 432 suspected meningitis cases were reported to health authorities in these three regions. The Ghana Ministry of Health, with assistance from CDC and other partners, tested cerebrospinal fluid (CSF) specimens from 286 patients. In the first 4 weeks of the outbreak, a high percentage of cases were caused by Streptococcus pneumoniae; followed by an increase in cases caused by Neisseria meningitidis, predominantly serogroup W. These data facilitated Ghana's request to the International Coordinating Group* for meningococcal polysaccharide ACW vaccine, which was delivered to persons in the most affected districts. Rapid identification of the etiologic agent causing meningitis outbreaks is critical to inform targeted public health and clinical interventions, including vaccination, clinical management, and contact precautions.

Background: Health care-associated infections (HAIs) are a major global public health concern. The lack of surveillance systems in developing countries leads to an underestimation of the global burden of HAI. We describe the process of developing a national HAI surveillance program and the magnitude of HAI rates in Egypt., Methods: The detailed process of implementation of a national HAI surveillance program is described. A 3-phase surveillance approach was implemented in intensive care units (ICUs). This article focuses on results from the phase 2 surveillance. Standard surveillance definitions were used, clinical samples were processed by the hospital laboratories, and results were confirmed by a reference laboratory., Results: Ninety-one ICUs in 28 hospitals contributed to 474,544 patient days and 2,688 HAIs. Of these, 30% were bloodstream infections, 29% were surgical site infections, 26% were pneumonia, and 15% were urinary tract infections. Ventilator-associated pneumonia had the highest incidence of device-associated infections (4.3/1,000 ventilator days). The most common pathogens reported were Klebsiella spp (28.7%) and Acinetobacter spp (13.7%). Of the Acinetobacter spp, 92.8% (157/169) were multidrug resistant, whereas 42.5% (151/355) of the Klebsiella spp and 54% (47/87) of Escherichia coli were extended-spectrum β-lactamase producers., Conclusions: Implementation of a sustainable surveillance system in a resource-limited country was possible following a stepwise approach with continuous evaluation. Enhancing infection prevention and control programs should be an infection control priority in Egypt., (Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.)

We assessed prevalence of and risk factors for candidaemia following Clostridium difficile infection (CDI) using longitudinal population-based surveillance. Of 13 615 adults with CDI, 113 (0·8%) developed candidaemia in the 120 days following CDI. In a matched case-control analysis, severe CDI and CDI treatment with vancomycin + metronidazole were associated with development of candidaemia following CDI.

Background.  Approximately 4 million Americans receive nursing home (NH) care annually. Nursing home residents commonly have risk factors for Clostridium difficile infection (CDI), including advanced age and antibiotic exposures. We estimated national incidence of NH-onset (NHO) CDI and patient outcomes. Methods.  We identified NHO-CDI cases from population-based surveillance of 10 geographic areas in the United States. Cases were defined by C difficile-positive stool collected in an NH (or from NH residents in outpatient settings or ≤3 days after hospital admission) without a positive stool in the prior 8 weeks. Medical records were reviewed on a sample of cases. Incidence was estimated using regression models accounting for age and laboratory testing method; sampling weights were applied to estimate hospitalizations, recurrences, and deaths. Results.  A total of 3503 NHO-CDI cases were identified. Among 262 sampled cases, median age was 82 years, 76% received antibiotics in the 12 weeks prior to the C difficile-positive specimen, and 57% were discharged from a hospital in the month before specimen collection. After adjusting for age and testing method, the 2012 national estimate for NHO-CDI incidence was 112 800 cases (95% confidence interval [CI], 93 400-131 800); 31 400 (28%) were hospitalized within 7 days after a positive specimen (95% CI, 25 500-37 300), 20 900 (19%) recurred within 14-60 days (95% CI, 14 600-27 100), and 8700 (8%) died within 30 days (95% CI, 6600-10 700). Conclusions.  Nursing home onset CDI is associated with substantial morbidity and mortality. Strategies focused on infection prevention in NHs and appropriate antibiotic use in both NHs and acute care settings may decrease the burden of NHO CDI.

Background: Significant progress has been made in reducing methicillin-resistant Staphylococcus aureus (MRSA) infections among hospitalized patients. However, the decreases in invasive MRSA infections among recently discharged patients have been less substantial. To inform prevention strategies, we assessed risk factors for invasive MRSA infection after acute-care hospitalizations., Methods: We conducted a prospective, matched case-control study. A case was defined as MRSA cultured from a normally sterile body site in a patient discharged from a hospital within the prior 12 weeks. Eligible case patients were identified from 15 hospitals across 6 US states. For each case patient, 2 controls were matched for hospital, month of discharge, and age group. Medical record reviews and telephone interviews were performed. Conditional logistic regression was used to identify independent risk factors for postdischarge invasive MRSA., Results: From 1 February 2011 through 31 March 2013, 194 case patients and 388 matched controls were enrolled. The median time between hospital discharge and positive culture was 23 days (range, 1-83 days). Factors independently associated with postdischarge MRSA infection included MRSA colonization (matched odds ratio [mOR], 7.71; 95% confidence interval [CI], 3.60-16.51), discharge to a nursing home (mOR, 2.65; 95% CI, 1.41-4.99), presence of a chronic wound during the postdischarge period (mOR, 4.41; 95% CI, 2.14-9.09), and discharge with a central venous catheter (mOR, 2.16; 95% CI, 1.13-4.99) or a different invasive device (mOR, 3.03; 95% CI, 1.24-7.39) in place., Conclusions: Prevention efforts should target patients with MRSA colonization or those with invasive devices or chronic wounds at hospital discharge. In addition, MRSA prevention efforts in nursing homes are warranted., (Published by Oxford University Press for the Infectious Diseases Society of America 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Background: Efforts to develop a Clostridium difficile vaccine are underway; identification of patients at risk for C. difficile infection (CDI) is critical to inform vaccine trials. We identified groups at high risk of CDI ≥ 2 8 days after hospital discharge., Methods: Hospital discharge data and pharmacy data from two large academic centers, in New York and Connecticut, were linked to active population-based CDI surveillance data from the Emerging Infections Program (EIP). Adult residents of the EIP surveillance area were included if they had an inpatient stay at a study hospital without prior history of CDI. The primary outcome was CDI by either toxin or molecular assay ≥ 28 days after an index hospitalization. Important predictors of CDI ≥ 28 days post discharge were initially identified through a Cox proportional hazards model (stepwise backward selection) using a derivation cohort; final model parameters were used to develop a risk score evaluated in the validation cohort., Results: Of the 35,186 index hospitalizations, 288 (0.82%) had CDI ≥ 28 days post discharge. After parameter selection, age, number of hospitalizations in the prior 90 days, admission diagnosis, and the use of 3rd/4th generation cephalosporin, clindamycin or fluoroquinolone antibiotic classes remained in the model. Using the validation cohort, the risk score was predictive (p<0.001) with a c-score of 0.75. Based on the distribution of scores in the derivation cohort, we divided the patients into low and high risk groups. In the high risk group, 1.6% experienced CDI ≥ 28 days post discharge compared to 0.3% among our low risk group., Conclusions: Our study identified specific parameters for a risk score that can be applied at discharge to identify a patient population whose risk of CDI ≥ 28 days following an acute care hospitalization was 5 times greater than other patients., (Published by Elsevier Ltd.)

Active Bacterial Core surveillance (ABCs) was established in 1995 as part of the Centers for Disease Control and Prevention Emerging Infections Program (EIP) network to assess the extent of invasive bacterial infections of public health importance. ABCs is distinctive among surveillance systems because of its large, population-based, geographically diverse catchment area; active laboratory-based identification of cases to ensure complete case capture; detailed collection of epidemiologic information paired with laboratory isolates; infrastructure that allows for more in-depth investigations; and sustained commitment of public health, academic, and clinical partners to maintain the system. ABCs has directly affected public health policies and practices through the development and evaluation of vaccines and other prevention strategies, the monitoring of antimicrobial drug resistance, and the response to public health emergencies and other emerging infections.

The Centers for Disease Control and Prevention Emerging Infections Program (EIP) network conducts population-based surveillance for pathogens of public health importance. Central to obtaining estimates of disease burden and tracking microbiological characteristics of these infections is accurate laboratory detection of pathogens. The use of culture-independent diagnostic tests (CIDTs) in clinical settings presents both opportunities and challenges to EIP surveillance. Because CIDTs offer better sensitivity than culture and are relatively easy to perform, their use could potentially improve estimates of disease burden. However, changes in clinical testing practices, use of tests with different sensitivities and specificities, and changes to case definitions make it challenging to monitor trends. Isolates are still needed for performing strain typing, antimicrobial resistance testing, and identifying other molecular characteristics of organisms. In this article, we outline current and future EIP activities to address issues associated with adoption of CIDTs, which may apply to other public health surveillance.

Background.  Antibiotic use predisposes patients to Clostridium difficile infections (CDI), and approximately 32% of these infections are community-associated (CA) CDI. The population-level impact of antibiotic use on adult CA-CDI rates is not well described. Methods.  We used 2011 active population- and laboratory-based surveillance data from 9 US geographic locations to identify adult CA-CDI cases, defined as C difficile-positive stool specimens (by toxin or molecular assay) collected from outpatients or from patients ≤3 days after hospital admission. All patients were surveillance area residents and aged ≥20 years with no positive test ≤8 weeks prior and no overnight stay in a healthcare facility ≤12 weeks prior. Outpatient oral antibiotic prescriptions dispensed in 2010 were obtained from the IMS Health Xponent database. Regression models examined the association between outpatient antibiotic prescribing and adult CA-CDI rates. Methods.  Healthcare providers prescribed 5.2 million courses of antibiotics among adults in the surveillance population in 2010, for an average of 0.73 per person. Across surveillance sites, antibiotic prescription rates (0.50-0.88 prescriptions per capita) and unadjusted CA-CDI rates (40.7-139.3 cases per 100 000 persons) varied. In regression modeling, reducing antibiotic prescribing rates by 10% among persons ≥20 years old was associated with a 17% (95% confidence interval, 6.0%-26.3%; P = .032) decrease in CA-CDI rates after adjusting for age, gender, race, and type of diagnostic assay. Reductions in prescribing penicillins and amoxicillin/clavulanic acid were associated with the greatest decreases in CA-CDI rates. Conclusions and Relevance.  Community-associated CDI prevention should include reducing unnecessary outpatient antibiotic use. A modest reduction of 10% in outpatient antibiotic prescribing can have a disproportionate impact on reducing CA-CDI rates.

Objective: To determine the potential epidemiologic and economic value of the implementation of a multifaceted Clostridium difficile infection (CDI) control program at US acute care hospitals, Design: Markov model with a 5-year time horizon, Participants: Patients whose data were used in our simulations were limited to hospitalized Medicare beneficiaries ≥65 years old., Background: CDI is an important public health problem with substantial associated morbidity, mortality, and cost. Multifaceted national prevention efforts in the United Kingdom, including antimicrobial stewardship, patient isolation, hand hygiene, environmental cleaning and disinfection, and audit, resulted in a 59% reduction in CDI cases reported from 2008 to 2012., Methods: Our analysis was conducted from the federal perspective. The intervention we modeled included the following components: antimicrobial stewardship utilizing the Antimicrobial Use and Resistance module of the National Healthcare Safety Network (NHSN), use of contact precautions, and enhanced environmental cleaning. We parameterized our model using data from CDC surveillance systems, the AHRQ Healthcare Cost and Utilization Project, and literature reviews. To address uncertainty in our parameter estimates, we conducted sensitivity analyses for intervention effectiveness and cost, expenditures by other federal partners, and discount rate. Each simulation represented a cohort of 1,000 hospitalized patients over 1,000 trials. RESULTS In our base case scenario with 50% intervention effectiveness, we estimated that 509,000 CDI cases and 82,000 CDI-attributable deaths would be prevented over a 5-year time horizon. Nationally, the cost savings across all hospitalizations would be $2.5 billion (95% credible interval: $1.2 billion to $4.0 billion)., Conclusions: The potential benefits of a multifaceted national CDI prevention program are sizeable from the federal perspective.

This article describes the global changes in Clostridium difficile epidemiology since the late twentieth century and into the twenty-first century when the new epidemic strain BI/NAP1/027 emerged. The article provides an overview of how understanding of C difficile epidemiology has rapidly evolved since its initial association with colitis in 1974. It also discusses how C difficile has spread across the globe, the role of asymptomatic carriers in disease transmission, the increased recognition of C difficile outside health care settings, the changes in epidemiology of C difficile infection in children, and the risk factors for disease., (Published by Elsevier Inc.)

Background: Patients in the neonatal intensive care unit (NICU) are at high risk for healthcare-associated infections. Variability in reported infection rates among NICUs exists, possibly related to differences in prevention strategies. A better understanding of current prevention practices may help identify prevention gaps and areas for further research., Methods: We surveyed infection control staff in NICUs reporting to the National Healthcare Safety Network (NHSN) to assess strategies used to prevent methicillin-resistant Staphylococcus aureus (MRSA) transmission and central line-associated bloodstream infections in NICUs., Results: Staff from 162 of 342 NICUs responded (response rate, 47.3%). Most (92.3%) NICUs use central line insertion and maintenance bundles, but maintenance practices varied, including agents used for antisepsis and frequency of dressing changes. Forty-two percent reported routine screening for MRSA colonization upon admission for all patients. Chlorhexidine gluconate (CHG) use for central line care for at least 1 indication (central line insertion, dressing changes, or port/cap antisepsis) was reported in 82 NICUs (51.3%). Among sixty-five NICUs responding to questions on CHG use restrictions, 46.2% reported no restrictions., Conclusions: Our survey illustrated heterogeneity of CLABSI and MRSA prevention practices and underscores the need for further research to define optimal strategies and evidence-based prevention recommendations for neonates.

Background: Clostridium difficile infection (CDI) is no longer restricted to hospital settings, and population-based incidence measures are needed. Understanding the determinants of CDI incidence will allow for more meaningful comparisons of rates and accurate national estimates., Methods: Data from active population- and laboratory-based CDI surveillance in 7 US states were used to identify CDI cases (ie, residents with positive C difficile stool specimen without a positive test in the prior 8 weeks). Cases were classified as community-associated (CA) if stool was collected as outpatients or ≤3 days of admission and no overnight healthcare facility stay in the past 12 weeks; otherwise, cases were classified as healthcare-associated (HA). Two regression models, one for CA-CDI and another for HA-CDI, were built to evaluate predictors of high CDI incidence. Site-specific incidence was adjusted based on the regression models., Results: Of 10 062 cases identified, 32% were CA. Crude incidence varied by geographic area; CA-CDI ranged from 28.2 to 79.1/100 000 and HA-CDI ranged from 45.7 to 155.9/100 000. Independent predictors of higher CA-CDI incidence were older age, white race, female gender, and nucleic acid amplification test (NAAT) use. For HA-CDI, older age and a greater number of inpatient-days were predictors. After adjusting for relevant predictors, the range of incidence narrowed greatly; CA-CDI rates ranged from 30.7 to 41.3/100 000 and HA-CDI rates ranged from 58.5 to 94.8/100 000., Conclusions: Differences in CDI incidence across geographic areas can be partially explained by differences in NAAT use, age, race, sex, and inpatient-days. Variation in antimicrobial use may contribute to the remaining differences in incidence.

Background: Studies are conflicting regarding the importance of the fluoroquinolone-resistant North American pulsed-field gel electrophoresis type 1 (NAP1) strain in Clostridium difficile infection (CDI) outcome. We describe strain types causing CDI and evaluate their association with patient outcomes., Methods: CDI cases were identified from population-based surveillance. Multivariate regression models were used to evaluate the associations of strain type with severe disease (ileus, toxic megacolon, or pseudomembranous colitis within 5 days; or white blood cell count ≥15 000 cells/µL within 1 day of positive test), severe outcome (intensive care unit admission after positive test, colectomy for C. difficile infection, or death within 30 days of positive test), and death within 14 days of positive test., Results: Strain typing results were available for 2057 cases. Severe disease occurred in 363 (17.7%) cases, severe outcome in 100 (4.9%), and death within 14 days in 56 (2.7%). The most common strain types were NAP1 (28.4%), NAP4 (10.2%), and NAP11 (9.1%). In unadjusted analysis, NAP1 was associated with greater odds of severe disease than other strains. After controlling for patient risk factors, healthcare exposure, and antibiotic use, NAP1 was associated with severe disease (adjusted odds ratio [AOR], 1.74; 95% confidence interval [CI], 1.36-2.22), severe outcome (AOR, 1.66; 95% CI, 1.09-2.54), and death within 14 days (AOR, 2.12; 95% CI, 1.22-3.68)., Conclusions: NAP1 was the most prevalent strain and a predictor of severe disease, severe outcome, and death. Strategies to reduce NAP1 prevalence, such as antibiotic stewardship to reduce fluoroquinolone use, might reduce CDI morbidity.

Objective: Little is known about the epidemiology of Clostridium difficile infection (CDI) among children, particularly children ≤3 years of age in whom colonization is common but pathogenicity uncertain. We sought to describe pediatric CDI incidence, clinical presentation, and outcomes across age groups., Methods: Data from an active population- and laboratory-based CDI surveillance in 10 US geographic areas during 2010-2011 were used to identify cases (ie, residents with C difficile-positive stool without a positive test in the previous 8 weeks). Community-associated (CA) cases had stool collected as outpatients or ≤3 days after hospital admission and no overnight health care facility stay in the previous 12 weeks. A convenience sample of CA cases were interviewed. Demographic, exposure, and clinical data for cases aged 1 to 17 years were compared across 4 age groups: 1 year, 2 to 3 years, 4 to 9 years, and 10 to 17 years., Results: Of 944 pediatric CDI cases identified, 71% were CA. CDI incidence per 100,000 children was highest among 1-year-old (66.3) and white (23.9) cases. The proportion of cases with documented diarrhea (72%) or severe disease (8%) was similar across age groups; no cases died. Among the 84 cases interviewed who reported diarrhea on the day of stool collection, 73% received antibiotics during the previous 12 weeks., Conclusions: Similar disease severity across age groups suggests an etiologic role for C difficile in the high rates of CDI observed in younger children. Prevention efforts to reduce unnecessary antimicrobial use among young children in outpatient settings should be prioritized.

We describe the adoption of nucleic acid amplification tests (NAAT) for Clostridium difficile diagnosis and their impact on stool rejection policies and C. difficile positivity rates. Of the laboratories with complete surveys, 51 (43%) reported using NAAT in 2011. Laboratories using NAAT had stricter rejection policies and increased positivity rates.

Objective: To report type and rates of healthcare-associated infections (HAIs) as well as pathogen distribution and antimicrobial resistance patterns from a pilot HAI surveillance system in Egypt., Methods: Prospective surveillance was conducted from April 2011 through March 2012 in 46 intensive care units (ICUs) in Egypt. Definitions were adapted from the Centers for Disease Control and Prevention's National Healthcare Safety Network. Trained healthcare workers identified HAIs and recorded data on clinical symptoms and up to 4 pathogens. A convenience sample of clinical isolates was tested for antimicrobial resistance at a central reference laboratory. Multidrug resistance was defined by international consensus criteria., Results: ICUs from 11 hospitals collected 90,515 patient-days of surveillance data. Of 472 HAIs identified, 47% were pneumonia, 22% were bloodstream infections, and 15% were urinary tract infections; case fatality among HAI case patients was 43%. The highest rate of device-associated infections was reported for ventilator-associated pneumonia (pooled mean rate, 7.47 cases per 1,000 ventilator-days). The most common pathogens reported were Acinetobacter species (21.8%) and Klebsiella species (18.4%). All Acinetobacter isolates tested (31/31) were multidrug resistant, and 71% (17/24) of Klebsiella pneumoniae isolates were extended-spectrum β-lactamase producers., Conclusions: Infection control priorities in Egypt should include preventing pneumonia and preventing infections due to antimicrobial-resistant pathogens.

Community-associated Clostridium difficile infection (CA-CDI) represents 32% of all CDI cases based on U.S. population-based data. The current epidemic strain, NAP1, is the most prevalent strain causing these infections. Although complications, recurrence and death are uncommon, one-fourth of the CA-CDI patients are hospitalized within 7 days after the diagnosis., (Published by Elsevier Ltd.)

Importance: Estimating the US burden of methicillin-resistant Staphylococcus aureus (MRSA) infections is important for planning and tracking success of prevention strategies., Objective: To describe updated national estimates and characteristics of health care- and community-associated invasive methicillin-resistant Staphylococcus aureus (MRSA) infections in 2011., Design, Setting, and Participants: Active laboratory-based case finding identified MRSA cultures in 9 US metropolitan areas from 2005 through 2011. Invasive infections (MRSA cultured from normally sterile body sites) were classified as health care-associated community-onset (HACO) infections (cultured ≤ 3 days after admission and/or prior year dialysis, hospitalization, surgery, long-term care residence, or central vascular catheter presence ≤ 2 days before culture); hospital-onset infections (cultured >3 days after admission); or community-associated infections if no other criteria were met. National estimates were adjusted using US census and US Renal Data System data., Main Outcomes and Measures: National estimates of invasive HACO, hospital-onset, and community-associated MRSA infections using US census and US Renal Data System data as the denominator., Results: An estimated 80,461 (95% CI, 69,515-93,914) invasive MRSA infections occurred nationally in 2011. Of these, 48,353 (95% CI, 40,195-58,642) were HACO infections; 14,156 (95% CI, 10,096-20,440) were hospital-onset infections; and 16,560 (95% CI, 12,806-21,811) were community-associated infections. Since 2005, adjusted national estimated incidence rates decreased among HACO infections by 27.7% and hospital-onset infections decreased by 54.2%; community-associated infections decreased by only 5.0%. Among recently hospitalized community-onset (nondialysis) infections, 64% occurred 3 months or less after discharge, and 32% of these were admitted from long-term care facilities., Conclusions and Relevance: An estimated 30,800 fewer invasive MRSA infections occurred in the United States in 2011 compared with 2005; in 2011 fewer infections occurred among patients during hospitalization than among persons in the community without recent health care exposures. Effective strategies for preventing infections outside acute care settings will have the greatest impact on further reducing invasive MRSA infections nationally.

Background: Approximately 15 700 invasive methicillin-resistant Staphylococcus aureus (MRSA) infections occurred in US dialysis patients in 2010. Frequent hospital visits and prolonged bloodstream access, especially via central venous catheters (CVCs), are risk factors among hemodialysis patients. We describe the epidemiology of and recent trends in invasive MRSA infections among dialysis patients., Methods: We analyzed population-based data from 9 US metropolitan areas from 2005 to 2011. Cases were defined as MRSA isolated from a normally sterile body site in a surveillance area resident who received dialysis, and were classified as hospital-onset (HO; culture collected >3 days after hospital admission) or healthcare-associated community-onset (HACO; all others). Incidence was calculated using denominators from the US Renal Data System. Temporal trends in incidence and national estimates were calculated controlling for age, sex, and race., Results: From 2005 to 2011, 7489 cases were identified; 85.7% were HACO infections, and 93.2% were bloodstream infections. Incidence of invasive MRSA infections decreased from 6.5 to 4.2 per 100 dialysis patients (annual decrease, 7.3%) with annual decreases of 6.7% for HACO and 10.5% for HO cases. Among cases identified during 2009-2011, 70% of patients were hospitalized in the year prior to infection. Among hemodialysis cases, 60.4% of patients were dialyzed through a CVC. The 2011 national estimated number of MRSA infections was 15 169., Conclusions: There has been a substantial decrease in invasive MRSA infection incidence among dialysis patients. Most cases had previous hospitalizations, suggesting that efforts to control MRSA in hospitals might have contributed to the declines. Infection prevention measures should include improved vascular access and CVC care.

Nucleic acid amplification testing (NAAT) is increasingly being adopted for diagnosis of Clostridium difficile infection (CDI). Data from 3 states conducting population-based CDI surveillance showed increases ranging from 43% to 67% in CDI incidence attributable to changing from toxin enzyme immunoassays to NAAT. CDI surveillance requires adjustment for testing methods.

Objective: To describe trends in the incidence of invasive methicillin-resistant Staphylococcus aureus (MRSA) infections in children during 2005-2010., Methods: We evaluated reports of invasive MRSA infections in pediatric patients identified from population-based surveillance during 2005-2010. Cases were defined as isolation of MRSA from a normally sterile site and classified on the basis of the setting of the positive culture and presence or absence of health care exposures. Estimated annual changes in incidence were determined by using regression models. National age- and race-specific incidences for 2010 were estimated by using US census data., Results: A total of 876 pediatric cases were reported; 340 (39%) were among infants. Overall, 35% of cases were hospital-onset, 23% were health care-associated community-onset, and 42% were community-associated (CA). The incidence of invasive CA-MRSA infection per 100000 children increased from 1.1 in 2005 to 1.7 in 2010 (modeled yearly increase: 10.2%; 95% confidence interval: 2.7%-18.2%). No significant trends were observed for health care-associated community-onset and hospital-onset cases. Nationally, estimated invasive MRSA incidence in 2010 was higher among infants aged <90 days compared with older infants and children (43.9 vs 2.0 per 100000) and among black children compared with other races (6.7 vs 1.6 per 100000)., Conclusions: Invasive MRSA infection in children disproportionately affects young infants and black children. In contrast to reports of declining incidence among adults, there were no significant reductions in health care-associated MRSA infections in children. Concurrently, the incidence of CA-MRSA infections has increased, underscoring the need for defining optimal strategies to prevent MRSA infections among children with and without health care exposures.

Background: The majority of invasive methicillin-resistant Staphylococcus aureus (MRSA) infections in the United States are community-onset and occur in persons with recent health care exposure., Methods: We performed a matched case-control study to identify risk factors for invasive MRSA infection among recently discharged patients. Cases had MRSA cultured from a normally sterile body site within 100 days following hospital discharge. Controls were matched on hospital, week of admission, and age., Results: Among 77 cases, the most common types of invasive MRSA infection were bloodstream infection and osteomyelitis. Independent risk factors were a history of a MRSA-positive clinical culture from a superficial body site in the 12 months preceding the invasive infection (matched odds ratio [mOR], 23; 95% confidence interval [CI]: 3.7-142), hemodialysis (mOR, 21; 95% CI: 1.7-257), prior hospitalization length of stay >5 days (mOR, 4.5; 95% CI: 1.6-12), and male sex (mOR, 2.9; 95% CI: 1.1-7.9)., Conclusion: Risk factors for postdischarge invasive MRSA infections can be identified prior to discharge and remain with the patient after the hospitalization ends. Measures to prevent community-onset invasive MRSA infections might start in the hospital but should also be evaluated in postdischarge settings., (Published by Mosby, Inc.)

Importance: Clostridium difficile infection (CDI) has been increasingly reported among healthy individuals in the community. Recent data suggest that community-associated CDI represents one-third of all C difficile cases. The epidemiology and potential sources of C difficile in the community are not fully understood., Objectives: To determine epidemiological and clinical characteristics of community-associated CDI and to explore potential sources of C difficile acquisition in the community., Design and Setting: Active population-based and laboratory-based CDI surveillance in 8 US states., Participants: Medical records were reviewed and interviews performed to assess outpatient, household, and food exposures among patients with community-associated CDI (ie, toxin or molecular assay positive for C difficile and no overnight stay in a health care facility within 12 weeks). Molecular characterization of C difficile isolates was performed. Outpatient health care exposure in the prior 12 weeks among patients with community-associated CDI was a priori categorized into the following 3 levels: no exposure, low-level exposure (ie, outpatient visit with physician or dentist), or high-level exposure (ie, surgery, dialysis, emergency or urgent care visit, inpatient care with no overnight stay, or health care personnel with direct patient care)., Main Outcomes and Measures: Prevalence of outpatient health care exposure among patients with community-associated CDI and identification of potential sources of C difficile by level of outpatient health care exposure., Results: Of 984 patients with community-associated CDI, 353 (35.9%) did not receive antibiotics, 177 (18.0%) had no outpatient health care exposure, and 400 (40.7%) had low-level outpatient health care exposure. Thirty-one percent of patients without antibiotic exposure received proton pump inhibitors. Patients having CDI with no or low-level outpatient health care exposure were more likely to be exposed to infants younger than 1 year (P = .04) and to household members with active CDI (P = .05) compared with those having high-level outpatient health care exposure. No association between food exposure or animal exposure and level of outpatient health care exposure was observed. North American pulsed-field gel electrophoresis (NAP) 1 was the most common (21.7%) strain isolated; NAP7 and NAP8 were uncommon (6.7%)., Conclusions and Relevance: Most patients with community-associated CDI had recent outpatient health care exposure, and up to 36% would not be prevented by reduction of antibiotic use only. Our data support evaluation of additional strategies, including further examination of C difficile transmission in outpatient and household settings and reduction of proton pump inhibitor use.

Objective: To describe rates and pathogen distribution of device-associated infections (DAIs) in neonatal intensive care unit (NICU) patients and compare differences in infection rates by hospital type (children's vs general hospitals)., Patients and Setting: Neonates in NICUs participating in the National Healthcare Safety Network from 2006 through 2008., Methods: We analyzed central line-associated bloodstream infections (CLABSIs), umbilical catheter-associated bloodstream infections (UCABs), and ventilator-associated pneumonia (VAP) among 304 NICUs. Differences in pooled mean incidence rates were examined using Poisson regression; nonparametric tests for comparing medians and rate distributions were used., Results: Pooled mean incidence rates by birth weight category (750 g or less, 751-1,000 g, 1,001-1,500 g, 1,501-2,500 g, and more than 2,500 g, respectively) were 3.94, 3.09, 2.25, 1.90, and 1.60 for CLABSI; 4.52, 2.77, 1.70, 0.91, and 0.92 for UCAB; and 2.36, 2.08, 1.28, 0.86, and 0.72 for VAP. When rates of infection between hospital types were compared, only pooled mean VAP rates were significantly lower in children's hospitals than in general hospitals among neonates weighing 1,000 g or less; no significant differences in medians or rate distributions were noted. Pathogen frequencies were coagulase-negative staphylococci (28%), Staphylococcus aureus (19%), and Candida species (13%) for bloodstream infections and Pseudomonas species (16%), S. aureus (15%), and Klebsiella species (14%) for VAP. Of 673 S. aureus isolates with susceptibility results, 33% were methicillin resistant., Conclusions: Neonates weighing 750 g or less had the highest DAI incidence. With the exception of VAP, pooled mean NICU incidence rates did not differ between children's and general hospitals. Pathogens associated with these infections can pose treatment challenges; continued efforts at prevention need to be applied to all NICU settings.

Background: Long-term care facility (LTCF) residents are at increased risk of Clostridium difficile infection (CDI). However, little is known about the incidence, recurrence, and severity of CDI in LTCFs or the extent to which acute care exposure contributes to CDI in LTCFs. We describe the epidemiology of CDI in a cohort of LTCF residents in Monroe County, New York, where recent estimates suggest a CDI incidence in hospitals of 9.2 cases per 10,000 patient-days., Design: Population-based surveillance study., Setting: Monroe County, New York. Patients. LTCF residents with onset of CDI while in the LTCF or less than 4 calendar-days after hospital admission from the LTCF from January 1 through December 31, 2010., Methods: We conducted surveillance for CDI in residents of 33 LTCFs. A CDI case was defined as a stool specimen positive for C. difficile obtained from a patient without a C. difficile-positive specimen in the previous 8 weeks; recurrence was defined as a stool specimen positive for C. difficile obtained between 2 and 8 weeks after the last C. difficile-positive stool specimen., Results: There were 425 LTCF-onset cases and 184 recurrences, which yielded an incidence of 2.3 cases per 10,000 resident-days (interquartile range [IQR], 1.2-3.3) and a recurrence rate of 1.0 case per 10,000 resident-days (IQR, 0.3-1.4). The cases occurred in 394 LTCF residents, and 52% of these residents developed CDI within 4 weeks after hospital discharge. Hospitalization for CDI occurred in 70 cases (16%). Of those cases that involved hospitalization for CDI, 70% were severe CDI, and 23% ended in death within 30 days after hospital admission., Conclusion: CDI incidence in Monroe County LTCFs is one-fourth the incidence among hospitalized patients. Approximately 50% of LTCF-onset cases occurred more than 4 weeks after hospital discharge, which emphasizes that prevention of CDI transmission should go beyond acute care settings.

The dramatic changes in the epidemiology of Clostridium difficile infection (CDI) during recent years, with increases in incidence and severity of disease in several countries, have made CDI a global public health challenge. Increases in CDI incidence have been largely attributed to the emergence of a previously rare and more virulent strain, BI/NAP1/027. Increased toxin production and high-level resistance to fluoroquinolones have made this strain a very successful pathogen in healthcare settings. In addition, populations previously thought to be at low risk are now being identified as having severe CDI. Recent genetic analysis suggests that C. difficile has a highly fluid genome with multiple mechanisms to modify its content and functionality, which can make C. difficile adaptable to environmental changes and potentially lead to the emergence of more virulent strains. In the face of these changes in the epidemiology and microbiology of CDI, surveillance systems are necessary to monitor trends and inform public health actions.

Background: Gram-negative bloodstream infections are an important cause of neonatal mortality. In October 2009, we investigated a Klebsiella spp outbreak in a neonatal intensive care unit in Guatemala., Methods: Probable cases were defined as a Klebsiella spp isolated from blood in neonates aged <28 days in the neonatal intensive care unit between October 1 and November 10, 2009; confirmed cases were identified as Klebsiella pneumoniae. Clinical data were abstracted from medical charts. K pneumoniae isolates were genotyped by pulsed-field gel electrophoresis (PFGE) and tested for antimicrobial susceptibility. Infection control practices were inspected., Results: There were 14 confirmed cases. The median age at onset of infection was 3 days (range, 2-8 days). Nine patients died (64%). K pneumoniae isolates were resistant to multiple antimicrobials. PFGE revealed 2 distinct clusters. Breaches in infection control procedures included inappropriate intravenous solution use and inadequate hand hygiene and contact precautions., Conclusions: We report a K pneumoniae outbreak with high neonatal mortality in Guatemala. PFGE clustering suggested a common source possibly related to reuse of a single-use intravenous medication or solution. The risk for K pneumoniae bloodstream infections in neonates in low-resource settings where sharing of solutions is common needs to be emphasized., (Copyright © 2012 Association for Professionals in Infection Control and Epidemiology, Inc. All rights reserved.)

Objectives: To assess trends in incidence of Candida spp. central line-associated bloodstream infections (CLABSIs) in US NICUs, 1999-2009., Methods: Data from NICUs participating in the National Nosocomial Infections Surveillance (1999-2004) and National Healthcare Safety Network (2006-2009) were analyzed. Overall and birth weight-specific incidence rates of Candida spp. CLABSIs per 1000 central line-days were calculated. Trends in incidence were assessed by using Poisson regression, and trends in proportion of CLABSIs identified as Candida albicans were assessed by using weighted-linear regression., Results: Overall, 398 NICUs reported 1407 Candida spp. CLABSIs (706 due to C albicans) among 1400 neonates. Of the 1400 neonates, 963 (69%) were ≤ 1000 g at the time of birth, and 182 (13%) died. From 1999 to 2009, the overall incidence decreased significantly for CLABSIs due to Candida spp. (0.92 vs 0.2), C albicans (0.53 vs 0.09), and non-albicans Candida spp. (0.39 vs 0.1). Birth weight-specific incidence significantly decreased across all birth weight categories for C albicans. For CLABSIs due to non-albicans Candida spp., significant decreases were detected among all birth weight categories, except among neonates 1501 to 2500 g. The proportion of Candida spp. CLABSIs due to C albicans did not significantly change over time, remaining at ~50%., Conclusions: Incidence of Candida spp. CLABSIs decreased substantially among NICU patients, regardless of birth weight. Decreases in incidence across all birth weight categories, and not only among neonates ≤ 1000 g in whom antifungal prophylaxis may be more common, suggest that multiple factors contributed to the declining incidence.

Background: The USA300 methicillin-resistant Staphylococcus aureus (MRSA) strain, which initially emerged as a cause of community-associated infections, has recently become an important pathogen in healthcare-associated infections (HAIs). However, its impact on patient outcomes has not been well studied. We evaluated patients with invasive MRSA infections to assess differences in outcomes between infections caused by USA100 and those caused by USA300., Methods: Population-based data for invasive MRSA infections were used to identify 2 cohorts: (1) nondialysis patients with central line-associated bloodstream infections (CLABSIs) and (2) patients with community-onset pneumonia (PNEUMO) during 2005-2007 from 6 US metropolitan areas. Medical records of patients with confirmed MRSA USA100 or USA300 infection were reviewed. Logistic regression and, when appropriate, survival analysis was performed to evaluate mortality, early and late complications, and length of stay., Results: A total of 236 and 100 patients were included in the CLABSI and PNEUMO cohorts, respectively. USA300 was the only independent predictor of early complications for PNEUMO patients (odds ratio [OR], 2.6; P = .02). Independent predictors of CLABSI late complications included intensive care unit (ICU) admission before MRSA culture (adjusted OR [AOR], 2.1; P= .01) and Charlson comorbidity index (AOR, 2.6; P = .003), but not strain type. PNEUMO patients were significantly more likely to die if they were older (P = .02), black (P < .001), or infected with USA100 strain (P = .02), whereas those with CLABSI were more likely to die if they were older (P < .001), had comorbidities (P < .001), or had an ICU admission before MRSA culture (P = .001)., Conclusions: USA300 was associated with early complications in PNEUMO patients. However, it was not associated with mortality for either PNEUMO or CLABSI patients. Concerns regarding higher mortality from HAIs caused by USA300 may not be warranted.

We describe clinical and laboratory characteristics of invasive methicillin-resistant Staphylococcus aureus (MRSA) infections with vancomycin MICs of 2 μg/ml and compare heteroresistant-intermediate S. aureus (hVISA) to non-hVISA. Health care-associated community-onset infections were the most common and resulted in frequent complications and relapses. hVISA-infected patients were more likely to have been hospitalized in the year prior to MRSA culture.

We compared incidence of methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection (BSI) in the United States and England by using population-based surveillance. The incidence of community-onset MRSA BSI was 6.3-fold higher in the United States than in England, whereas the incidence of hospital-onset MRSA BSI was similar between the 2 countries.

Purpose: To evaluate the antibacterial effect of different chlorhexidine (CHX) concentrations against Streptococcus mutans using the agar-diffusion method with and without human dentin discs placed between the bacteria and the test substances., Methods: For the direct application (agar-well technique), a base layer containing 15 mL of BHI agar and 300 microL of S. mutans inoculum (10(9) cfu/mL) was prepared in Petri dishes. Six wells per dish were made at equidistant points and immediately filled with CHX gels (0.12%, 0.2%, 1% and 2%), 35% phosphoric acid and pure natrosol (n = 6 wells/substance). Paper discs soaked in sterile distilled water served as control group (n = 6). For the indirect application (transdentinal diffusion), 0.2 mm- and 0.5 mm-thick human dentin discs (36 discs/thickness) had the hydraulic conductance determined, which allowed the homogeneous allocation of them to the experimental and control groups. The discs were placed at equidistant points on the Petri dishes containing BHI with the S. mutans inoculum (six discs per dish; one per substance) with the pulpal side in contact with the bacteria. In the discs treated with CHX gels, dentin surface was etched with H3PO4 and rinsed with distilled water before CHX gel application for 1 minute. After both direct and indirect application, the dishes were incubated for 24 hours and the bacterial growth inhibition zones formed around the wells and dentin discs were measured. Data were analyzed statistically by the non-parametric Kruskal-Wallis and Mann-Whitney tests at 5% significance level., Results: In the direct test, all CHX concentrations presented a dose-dependent antibacterial activity against S. mutans. In the indirect test, there were statistically significant differences (P < 0.05) among all groups and the largest microbial growth inhibition zones were observed when 2% CHX was applied on 0.2 mm-thick discs (P < 0.05). It was concluded that all evaluated CHX gels exhibited both direct and transdentinal antibacterial activity against S. mutans. This effect of CHX was strongly influenced by the CHX concentration as well as the dentin barrier thickness.

Unlabelled: This in vitro study evaluated the cytotoxicity of an experimental restorative composite resin subjected to different light-curing regimens., Methods: Forty round-shaped specimens were prepared and randomly assigned to four experimental groups (n=10), as follows: in Group 1, no light-curing; in Groups 2, 3 and 4, the composite resin specimens were light-cured for 20, 40 or 60 s, respectively. In Group 5, filter paper discs soaked in 5 µL PBS were used as negative controls. The resin specimens and paper discs were placed in wells of 24-well plates in which the odontoblast-like cells MDPC-23 (30,000 cells/cm²) were plated and incubated in a humidified incubator with 5% CO2 and 95% air at 37ºC for 72 h. The cytotoxicity was evaluated by the cell metabolism (MTT assay) and cell morphology (SEM). The data were analyzed statistically by Kruskal-Wallis and Mann-Whitney tests (p<0.05)., Results: In G1, cell metabolism decreased by 86.2%, indicating a severe cytotoxicity of the non-light-cured composite resin. On the other hand, cell metabolism decreased by only 13.3% and 13.5% in G2 and G3, respectively. No cytotoxic effects were observed in G4 and G5. In G1, only a few round-shaped cells with short processes on their cytoplasmic membrane were observed. In the other experimental groups as well as in control group, a number of spindle-shaped cells with long cytoplasmic processes were found., Conclusion: Regardless of the photoactivation time used in the present investigation, the experimental composite resin presented mild to no toxic effects to the odontoblast-like MDPC-23 cells. However, intense cytotoxic effects occurred when no light-curing was performed.

Objectives: To evaluate the cytotoxic effects of a bleaching agent composed of 0.01% carbamide peroxide (CP; 2.21mug/ml H(2)O(2)) on the MDPC-23 odontoblastic cell line, and to determine whether sodium ascorbate (SA) is capable of reducing, or even eliminating, the toxic effects caused by this bleaching agent., Methods: The cells were seeded in wells and incubated for 48 hours. CP and SA were dissolved in a culture medium (DMEM) in order to obtain experimental extracts. Six groups of cells (n=10) were treated as follows: G1: no treatment (control); G2: 0.25 mM SA/60 min; G3: 0.5 mM SA/60 min; G4: 0.25 mM SA+0.01% CP/60 min; G5: 0.5 mM SA+0.01% CP/60 min; and G6: 0.01% CP/60 min. The cell metabolism was evaluated by MTT assay, and the cell morphology was assessed by scanning electron microscopy. The data obtained were analyzed by 2-way ANOVA and post-hoc Tukey's test (alpha=5%)., Results: THE PERCENTAGES OF CELL METABOLISM WERE AS FOLLOWS: G1 (control)=100%; G2=110.06%, G3=108.57%, G4=90.35%, G5=97.63%, and G6=66.88%. Group 6 presented a statistically lower cell metabolism than did the other groups, and the cells that remained on the substrate exhibited changes in their morphology. SA decreased the cytotoxic effects caused by CP, demonstrating its protective effect against the toxic components of this dental product., Conclusions: It was concluded that CP gel has cytopathic effects on MDPC-23 odontoblastic cells, even at low concentrations such as 0.01%. SA at 0.25 mM, and that 0.5 mM is able to protect these cultured cells against the cytotoxic effects of CP.

This study evaluated the cytotoxic effects of 2 mineral trioxide aggregate (MTA) cements - White-MTA-Angelus and a new formulation, MTA-Bio - on odontoblast-like cell (MDPC-23) cultures. Twenty-four disc-shaped (2 mm diameter x 2 mm thick) specimens were fabricated from each material and immersed individually in wells containing 1 mL of DMEM culture medium for either 24 h or 7 days to obtain extracts, giving rise to 4 groups of 12 specimens each: G1 - White-MTA/24 h; G2 - White-MTA/7 days; G3 - MTA-Bio/24 h; and G4 - MTA-Bio/7 days. Plain culture medium (DMEM) was used as a negative control (G5). Cells at 30,000 cells/cm(2) concentration were seeded in the wells of 24-well plates and incubated in a humidified incubator with 5% CO2 and 95% air at 37 degrees C for 72 h. After this period, the culture medium of each well was replaced by 1 mL of extract (or plain DMEM in the control group) and the cells were incubated for additional 2 h. Cell metabolism was evaluated by the MTT assay and the data were analyzed statistically by ANOVA and Tukey's test (alpha=0.05). Cell morphology and the surface of representative MTA specimens of each group were examined by scanning electron microscopy. There was no statistically significant difference (p>0.05) between G1 and G2 or between G3 and G4. No significant difference (p>0.05) was found between the experimental and control groups either. Similar cell organization and morphology were observed in all groups, regardless of the storage periods. However, the number of cells observed in the experimental groups decreased compared to the control group. MTA-Bio presented irregular surface with more porosities than White-MTA. In conclusion, White-MTA and MTA-Bio presented low cytotoxic effects on odontoblast-like cell (MDPC-23) cultures.

Unlabelled: Chlorhexidine gluconate (CHX) is recommended for a number of clinical procedures and it has been pointed out as a potential cavity cleanser to be applied before adhesive restoration of dental cavities., Objective: As CHX may diffuse through the dentinal tubules to reach a monolayer of odontoblasts that underlies the dentin substrate, this study evaluated the cytotoxic effects of different concentrations of CHX on cultured odontoblast-like cells (MDPC-23)., Material and Methods: Cells were cultured and exposed to CHX solutions at concentrations of 0.06%, 0.12%, 0.2%, 1% and 2%. Pure culture medium (alpha-MEM) and 3% hydrogen peroxide were used as negative and positive control, respectively. After exposing the cultured cells to the controls and CHX solutions for 60 s, 2 h or 60 s with a 24-h recovery period, cell metabolism (MTT assay) and total protein concentration were evaluated. Cell morphology was assessed under scanning electron microscopy. CHX had a dose-dependent toxic effect on the MDPC-23 cells., Results: Statistically significant difference was observed when the cells were exposed to CHX in all periods (p<0.05). Significant difference was also determined for all CHX concentrations (p<0.05). The 60-s exposure time was the least cytotoxic (p<0.05), while exposure to CHX for 60 s with a 24-h recovery period was the most toxic to the cells (p<0.05)., Conclusion: Regardless of the exposure time, all CHX concentrations had a high direct cytotoxic effect to cultured MDPC-23 cells.

It has been demonstrated that chlorhexidine digluconate (CHX) is capable of eliminating bacteria that may remain lodged in dentin after mechanical caries removal. In addition, the use of CHX on acid-etched dentin before adhesive system application delays the resin-dentin interface degradation, maintaining the integrity of the adhesive restorations. Despite these advantages of using CHX in restorative dentistry, when applied on dentin, this chemical agent may diffuse across dentinal tubules to cause toxic effects to the pulp cells. The aim of this study was to evaluate the transdentinal cytotoxic effects caused by different concentrations of CHX gels applied on acid-conditioned dentin substrate. Dentin discs (0.2-mm and 0.5-mm thick) were cut from human third molars and mounted in artificial pulp chambers. Odontoblast-like MDPC-23 cells (50,000 cells/cm(2)) were seeded on the pulpal side of the discs, and the carbon polymer gel (natrosol) with different CHX concentrations (0.12, 0.2, 1, and 2%), 35% phosphoric acid, or pure natrosol were applied on the occlusal side of the discs, forming six treatment groups (n = 10 discs/thickness). The dentin discs in the control group (n = 10 discs/thickness) did not receive any treatment. In each group, cell metabolism was analyzed by the methyltetrazolium assay (n = 8/thickness), and cell morphology was assessed by scanning electron microscopy (n = 2/thickness). Statistical analysis showed that CHX gels had a dose-dependent toxic effect on the odontoblast-like cells. Cell metabolism decreased by 12.8, 14.6, 18.3, 26, 13.7, and 10.5% for the 0.5-mm-thick dentin discs and 23, 26.3, 28.1, 34.5, 22.5, and 19.4% for the 0.2-mm-thick dentin discs treated with 0.12% CHX, 0.2% CHX, 1% CHX, 2% CHX, H(3)PO(4), and pure natrosol, respectively. According to the experimental conditions of the current investigation, it may be concluded that the application of natrosol gel with different concentrations of CHX on acid-conditioned dentin causes mild transdentinal cytotoxic effects to the MDPC-23 cells in a dose-dependent manner. Dentin acted as a biological barrier against CHX diffusion, and this effect was directly related to dentin thickness., ((c) 2009 Wiley Periodicals, Inc.)

Background: Adenoviruses can cause outbreaks of febrile respiratory illness in military trainees, but until 2007, adenovirus serotype 14 (Ad14) was never associated with such outbreaks. From April through June 2007, 15 trainees at one base were hospitalized for pneumonia due to Ad14. Subsequent reports of febrile respiratory illness among health care personnel suggested nosocomial transmission., Methods: Health care personnel participants completed a questionnaire and provided blood and nasal wash specimens for Ad14 diagnostic testing. We defined a confirmed case of Ad14 infection as one with titers > or = 1:80 or nasal wash specimens positive for Ad14 by polymerase chain reaction, whereas a possible case was defined by titers of 1:20 or 1:40. We also collected environmental samples., Results: Among 218 tested health care personnel, 35 (16%) had titers > or = 1:20; of these, 7 had possible cases and 28 had confirmed cases of infection. Confirmed case patients were more likely to report febrile respiratory illness (57% vs 11%; P< .001) and to have had direct contact with patients with Ad14 infection (82% vs 62%; P.04 ). Of the 23 confirmed case patients with direct contact with Ad14-infected patients, 52% reported that patients were not in contact and droplet precautions at the time of exposure. Ad14 was recovered from several hospital surfaces., Conclusion: Our findings of possible nosocomial transmission of Ad14 highlight the need to reinforce infection control guidelines.

Objective: This study evaluated transenamel and transdentinal cytotoxic effects of a bleaching gel on the MDPC-23 cell line., Study Design: Discs obtained from bovine incisors were placed in a metallic device to simulate an in vivo pulp chamber. Groups were formed according to the enamel surface treatment: G1: 35% H(2)O(2) bleaching gel; G2: 35% H(2)O(2) bleaching gel + halogen light; G3: halogen light; and G4: control. Cell metabolism was evaluated by the methyltetrazolium assay and cell morphology by scanning electron microscopy., Results: Cell metabolism decreased by 31.7%, 41.6%, and 11.5% in G1, G2, and G3, respectively. Cytotoxic effects observed in G2 were significantly more severe compared with G3 and G4. In G1 and G2, a smaller number of viable cells with major morphologic alterations remained adhered to dentin., Conclusion: The bleaching gel associated with light presented transenamel and transdentinal cytotoxic effects characterised by direct damage to odontoblasts and decrease of their metabolic activity.

This study evaluated the cytotoxic effects of a carbamide peroxide (CP) bleaching gel at different concentrations on odontoblast-like cells. Immortalized cells of the MDPC-23 cell line (30,000 cells/cm(2)) were incubated for 48 h. The bleaching gel was diluted in DMEM culture medium originating extracts with different CP concentrations. The amount (microg/mL) of hydrogen peroxide (H(2)O(2)) released from each extract was measured by the leukocrystal violet/horseradish peroxidase enzyme assay. Five groups (n = 10) were formed according to the CP concentration in the extracts: G1-DMEM (control); G2-0.0001% CP (0.025 microg/mL H(2)O(2)); G3-0.001% CP (0.43 microg/mL H(2)O(2)); G4-0.01% CP (2.21 microg/mL H(2)O(2)); and G5-0.1% CP (29.74 microg/mL H(2)O(2)). MDPC-23 cells were exposed to the bleaching gel extracts for 60 min and cell metabolism was evaluated by the MTT assay. Data were analyzed statistically by one-way ANOVA and Tukey's test (alpha = 0.05). Cell morphology was examined by scanning electron microscopy. The percentages of viable cells were as follows: G1, 100%; G2, 89.41%; G3, 82.4%; G4, 61.5%; and G5, 23.0%. G2 and G3 did not differ significantly (p > 0.05) from G1. The most severe cytotoxic effects were observed in G3 and G4. In conclusion, even at low concentrations, the CP gel extracts presented cytotoxic effects. This cytotoxicity was dose-dependent, and the 0.1% CP concentration caused the most intense cytopathic effects to the MDPC-23 cells.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is increasingly being reported to cause outbreaks in neonatal intensive care units (NICUs). We assessed the scope and magnitude of MRSA infections with disease onset after 3 days of age (late-onset MRSA infections) in NICUs., Methods: We analyzed data reported by NICUs participating in the National Nosocomial Infections Surveillance system from 1995 through 2004. For each surveillance month, all healthcare-associated infections as defined by National Nosocomial Infections Surveillance criteria were reported, along with antimicrobial susceptibility patterns of the isolates. We pooled the data from all NICUs by birth weight category and calendar year. Poisson regression was used to assess changes in incidence of late-onset MRSA infections per 10,000 patient-days., Results: Overall, 149 NICUs reported 4831 S. aureus infections and 5,878,139 patient-days. Methicillin testing data were available for 4302 S. aureus isolates, of which 975 (23%) were MRSA. Incidence of late-onset MRSA infection per 10,000 patient-days, combining all birthweight categories, increased 308% from 0.7 in 1995 to 3.1 in 2004 (P < 0.001). A significant increase in incidence of MRSA infections was observed among all 4 birthweight categories analyzed separately (2500 g). The distribution of MRSA infection by type of infection did not vary during the study period; 299 (31%) of MRSA infections were bloodstream infections, 174 (18%) were pneumonia, and 161 (17%) were conjunctivitis., Conclusion: The incidence of late-onset MRSA infections increased substantially between 1995 and 2004, indicating a need to reinforce infection control recommendations and to explore potential sources and routes of transmission.

Purpose: To evaluate the cytotoxic effects of resin-based light-cured liners on culture of pulp cells., Methods: Discs measuring 4 mm in diameter and 2 mm thick were fabricated from TheraCal (TCMTA), Vitrebond (VIT), and Ultrablend Plus (UBP). These specimens were immersed in serum-free culture medium (DMEM) for 24 hours or 7 days to produce the extracts. After incubating the pulp cells for 72 hours, the extracts were applied on the cells and the cytotoxic effects were determined based on the cell metabolism (MTT), total protein expression and cell morphology (SEM). In the control group, fresh DMEM was used. Data from MTT analysis and protein expression were submitted to Kruskal-Wallis and Mann-Whitney tests at the preset level of significance of 5%., Results: When in contact with the 24-hour extract, TCMTA, VIT, and UBP decreased the cell metabolism by 31.5%, 73.5% and 71.0%, respectively. The total protein expressed by the cells in contact with VIT and UBP was lower than TCMTA and DMEM (Mann-Whitney, P < 0.05). When in contact with the 7-day extract, TCMTA, VIT, and UBP decreased the metabolic activity by 45.9%, 77.1% and 64.4%, respectively. All the liners expressed statistically lower amounts of proteins when compared to the control. A reduction in the number of cells was observed for all liners. The remaining cells from TCMTA group resembled those from the control group while for VIT and UBP the cells presented significant morphological alterations.

Aim: To evaluate the trans-enamel and trans-dentinal cytotoxic effects of a 35% H(2)O(2) bleaching gel on an odontoblast-like cell lines (MDPC-23) after consecutive applications., Methodology: Fifteen enamel/dentine discs were obtained from bovine central incisor teeth and placed individually in artificial pulp chambers. Three groups (n = 5 discs) were formed according to the following enamel treatments: G1: 35% H(2)O(2) bleaching gel (15 min); G2: 35% H(2)O(2) bleaching gel (15 min) + halogen light (20 s); G3: control (no treatment). After repeating the treatments three consecutive times, the extracts (culture medium + gel components that had diffused through enamel/dentine discs) in contact with the dentine were collected and applied to previously cultured MDPC-23 cells (50 000 cells cm(-2)) for 24 h. Cell metabolism was evaluated by the MTT assay and data were analysed statistically (alpha = 5%; Kruskal-Wallis and Mann-Whitney U-test). Cell morphology was analysed by scanning electron microscopy., Results: Cell metabolism decreased by 92.03% and 82.47% in G1 and G2 respectively. G1 and G2 differed significantly (P < 0.05) from G3. Regardless of halogen light activation, the application of the bleaching gel on the cultured odontoblast-like cells caused significantly more severe cytotoxic effects than those observed in the nontreated control group. In addition, significant morphological cell alterations were observed in G1 and G2., Conclusion: After three consecutive applications of a 35% H(2)O(2) bleaching agent, the diffusion of the gel components through enamel and dentine caused severe toxic effects to cultured pulp cells.

Introduction: This randomized clinical trial assessed, by using microbial culture and scanning electron microscopy (SEM), the contamination by mutans streptococci (MS) colonies/biofilms on acrylic baseplates of removable orthodontic appliances and evaluated the efficacy of antimicrobial sprays (Periogard [Colgate-Palmolive Ind. Brasileira, Osasco, SP, Brazil], Cepacol [Merrell Lepetit Farmacêutica e Industrial Ltda, Santo Amaro, SP, Brazil], and sterile tap water [control]) on their disinfection., Methods: Seventeen children were randomly enrolled in a 3-stage changeover system with a 1-week interval between each stage. All solutions were used in all stages by a different group of children. The acrylic baseplates were worn full time except at meals. At the end of each week of the trial, the baseplates were submitted to a randomized disinfection protocol and were sent for microbiologic analysis. New baseplates were constructed, and the same sequence of procedures was repeated 2 more times. Acrylic baseplates representing each test solution were examined by SEM. The Friedman test assessed differences at the 5% significance level among the solutions for MS biofilm formation on acrylic surface., Results: Cepacol and Periogard reduced the formation of MS colonies/biofilms, and both solutions differed statistically from sterile tap water (P <.001). However, Periogard was significantly more effective against MS than Cepacol (P <.001). When MS colonies/biofilms were detected on acrylic surfaces under stereomicroscopy, this was confirmed with SEM., Conclusions: Acrylic baseplates of removable orthodontic appliances worn by children were contaminated by MS colonies/biofilms in all cases after 1 week. Although Cepacol had better results than sterile tap water, spraying with Periogard showed significantly greater efficacy in reducing MS colonies/biofilms on acrylic surfaces.

Introduction: Atresia of the maxilla is a transverse skeletal dysplasia, possibly associated with respiratory problems. For its correction, rapid maxillary expansion is a feasible orthodontic process., Objective: To evaluate the effect of rapid maxillary expansion on the nasal cavity by acoustic rhinometry and computed rhinomanometry., Material and Methods: Twenty-nine children of both sexes with oral and/or mixed breathing, ranging in age from 7 to 10 years and with mixed dentition were selected. The children had uni- or bilateral posterior crossbite involving deciduous canines and the first permanent molars and were not being submitted to any otorhinolaryngologic or orthodontic treatment. All subjects were submitted to rhinologic exams and orthodontic documentation at three different times, i.e., before expansion and immediately and 90 days after expansion., Results: There was no difference in the minimal cross-sectional area at the level of the valve and inferior nasal turbinate between the periods analyzed, but there was a statistically significant reduction in nasal resistance after expansion., Conclusion: On the basis of the present results, we may conclude that rapid maxillary expansion may lessen the nasal resistance. Although there was no difference in nasal geometry. Thus, this procedure may improve nasal respiration, but cannot be indicated for this purpose by itself.

Cri du Chat Syndrome occurs as a result of a partial deletion in the short arm of chromosome 5. Among the consequent abnormalities are low birth weight, a striking catlike cry in infancy, mental retardation, epicanthal folds, hypertelorism and dental malocclusions. This paper presents a case report on the dental treatment of a 23-year-old patient who received multidisciplinary treatment, including special education and precocious stimulation for carriers of this syndrome.

Purpose: The purpose of this study was to investigate the shear bond strength of 2 resin-based pit-and-fissure sealants--Clinpro and Fluroshield--to saliva-contaminated and noncontaminated enamel., Methods: Forty buccal halves of permanent molar crowns were individually embedded in polyester resin and ground with wet silicone carbide papers to obtain flat enamel surfaces. The specimens were randomly assigned to 2 groups: (A) without contamination; and (B) contaminated with 0.01 ml of fresh human saliva. Each group was divided into 2 subgroups (N=10), according to the sealant applied: (1) Clinpro; and (2) Fluroshield. Shear bond strength was tested at a crosshead speed of 0.5 mm/min. Failure mode was assessed., Results: Means (MPa) were: (1) A1=7.66 +/- 3.12; A2=12.39 +/- 4.34; (2) B1=5.05 +/- 1.44; B2=10.44 +/- 2.35. Data were submitted to analysis of variance and Scheffé's statistical test (P<.05). There was a statistically significant difference (P<.05) between both the sealants and the experimental conditions analyzed. Fluroshield provided higher bond strength and was different from Clinpro (P<.05) in the absence of contamination. Within the saliva-contaminated group, however, no statistically significant difference (P>.05) was observed between the tested materials., Conclusions: It may be concluded that, under dry conditions, the filled pit-and-fissure sealant (Fluroshield) yielded better bonding performance. Salivary contamination undermined the adhesion of both materials to enamel and resulted in lower bond strengths.