Matthew J. Kuehnert

Changes in the Prevalence of Nasal Colonization with Staphylococcus aureus in the United States, 2001–2004

BACKGROUND Staphylococcus aureus is a common cause of infection, particularly in persons colonized by this organism. Virulent strains of methicillin-resistant S. aureus (MRSA) have emerged in the general community. METHODS A nationally representative survey of nasal colonization with S. aureus was conducted from 2001 through 2004 as part of the National Health and Nutrition Examination Survey. MRSA isolates were identified by the oxacillin disk-diffusion method. The pulsed-field gel electrophoresis (PFGE) type was determined for all MRSA isolates. A t statistic was used to compare the prevalence of colonization across biennia and across population subgroups. Cofactors independently associated with colonization were determined with backward stepwise logistic modeling. RESULTS The prevalence of colonization with S. aureus decreased from 32.4% in 2001-2002 to 28.6% in 2003-2004 (P < .01), whereas the prevalence of colonization with MRSA increased from 0.8% to 1.5% (P < .05). Colonization with MRSA was independently associated with healthcare exposure in males and with having been born in the United States, age > or =60 years, diabetes, and poverty in females. In 2003-2004, a total of 19.7% (95% confidence interval, 12.4%-28.8%) of MRSA-colonized persons carried a PFGE type associated with community transmission. CONCLUSIONS Nasal colonization with MRSA has increased in the United States, despite an overall decrease in nasal colonization with S. aureus. PFGE types associated with community transmission only partially account for the increase in MRSA colonization.

Prevalence of Staphylococcus aureus Nasal Colonization in the United States, 2001–2002

BACKGROUND Staphylococcus aureus is a common cause of disease, particularly in colonized persons. Although methicillin-resistant S. aureus (MRSA) infection has become increasingly reported, population-based S. aureus and MRSA colonization estimates are lacking. METHODS Nasal samples for S. aureus culture and sociodemographic data were obtained from 9622 persons > or = 1 year old as part of the National Health and Nutrition Examination Survey, 2001-2002. After screening for oxacillin susceptibility, MRSA and selected methicillin-susceptible S. aureus isolates were tested for antimicrobial susceptibility, pulsed-field gel electrophoresis clonal type, toxin genes (e.g., for Panton-Valentine leukocidin [PVL]), and staphylococcal cassette chromosome mec (SCCmec) type I-IV genes. RESULTS For 2001-2002, national S. aureus and MRSA colonization prevalence estimates were 32.4% (95% confidence interval [CI], 30.7%-34.1%) and 0.8% (95% CI, 0.4%-1.4%), respectively, and population estimates were 89.4 million persons (95% CI, 84.8-94.1 million persons) and 2.3 million persons (95% CI, 1.2-3.8 million persons), respectively. S. aureus colonization prevalence was highest in participants 6-11 years old. MRSA colonization was associated with age > or = 60 years and being female but not with recent health-care exposure. In unweighted analyses, the SCCmec type IV gene was more frequent in isolates from participants of younger age and of non-Hispanic black race/ethnicity; the PVL gene was present in 9 (2.4%) of 372 of isolates tested. CONCLUSIONS Many persons in the United States are colonized with S. aureus; prevalence rates differ demographically. MRSA colonization prevalence, although low nationally in 2001-2002, may vary with demographic and organism characteristics.

Transmission of Influenza: Implications for Control in Health Care Settings

Annual influenza epidemics in the United States result in an average of >36,000 deaths and 114,000 hospitalizations. Influenza can spread rapidly to patients and health care personnel in health care settings after influenza is introduced by visitors, staff, or patients. Influenza outbreaks in health care facilities can have potentially devastating consequences, particularly for immunocompromised persons. Although vaccination of health care personnel and patients is the primary means to prevent and control outbreaks of influenza in health care settings, antiviral influenza medications and isolation precautions are important adjuncts. Although droplet transmission is thought to be the primary mode of influenza transmission, limited evidence is available to support the relative clinical importance of contact, droplet, and droplet nuclei (airborne) transmission of influenza. In this article, the results of studies on the modes of influenza transmission and their relevant isolation precautions are reviewed.

Transfusion‐transmitted bacterial infectionin the United States, 1998 through 2000

BACKGROUND: Bacterial contamination of blood components can result in transfusion‐transmitted infection, but the risk is not established.

Control of Vancomycin-Resistant Enterococcus in Health Care Facilities in a Region

BACKGROUND In late 1996, vancomycin-resistant enterococci were first detected in the Siouxland region of Iowa, Nebraska, and South Dakota. A task force was created, and in 1997 the assistance of the Centers for Disease Control and Prevention was sought in assessing the prevalence of vancomycin-resistant enterococci in the regions facilities and implementing recommendations for screening, infection control, and education at all 32 health care facilities in the region. METHODS The infection-control intervention was evaluated in October 1998 and October 1999. We performed point-prevalence surveys, conducted a case-control study of gastrointestinal colonization with vancomycin-resistant enterococci, and compared infection-control practices and screening policies for vancomycin-resistant enterococci at the acute care and long-term care facilities in the Siouxland region. RESULTS Perianal-swab samples were obtained from 1954 of 2196 eligible patients (89 percent) in 1998 and 1820 of 2049 eligible patients (89 percent) in 1999. The overall prevalence of vancomycin-resistant enterococci at 30 facilities that participated in all three years of the study decreased from 2.2 percent in 1997 to 1.4 percent in 1998 and to 0.5 percent in 1999 (P<0.001 by chi-square test for trend). The number of facilities that had had at least one patient with vancomycin-resistant enterococci declined from 15 in 1997 to 10 in 1998 to only 5 in 1999. At both acute care and long-term care facilities, the risk factors for colonization with vancomycin-resistant enterococci were prior hospitalization and treatment with antimicrobial agents. Most of the long-term care facilities screened for vancomycin-resistant enterococci (26 of 28 in 1998 [93 percent] and 23 of 25 in 1999 [92 percent]) and had infection-control policies to prevent the transmission of vancomycin-resistant enterococci (22 of 25 [88 percent] in 1999). All four acute care facilities had screening and infection-control policies for vancomycin-resistant enterococci in 1998 and 1999. CONCLUSIONS An active infection-control intervention, which includes the obtaining of surveillance cultures and the isolation of infected patients, can reduce or eliminate the transmission of vancomycin-resistant enterococci in the health care facilities of a region.

Methicillin-resistant–Staphylococcus aureus Hospitalizations, United States

Methicillin-resistant Staphylococcus aureus (MRSA) is increasingly a cause of nosocomial and community-onset infection with unknown national scope and magnitude. We used the National Hospital Discharge Survey to calculate the number of US hospital discharges listing S. aureus–specific diagnoses, defined as those having at least 1 International Classification of Diseases (ICD)-9 code specific for S. aureus infection. The number of hospital discharges listing S. aureus-specific diagnoses was multiplied by the proportion of methicillin resistance for each corresponding infection site to determine the number of MRSA infections. From 1999 to 2000, an estimated 125,969 hospitalizations with a diagnosis of MRSA infection occurred annually, including 31,440 for septicemia, 29,823 for pneumonia, and 64,706 for other infections, accounting for 3.95 per 1,000 hospital discharges. The method used in our analysis may provide a simple way to assess trends of the magnitude of MRSA infection nationally.

Donor‐Derived Disease Transmission Events in the United States: Data Reviewed by the OPTN/UNOS Disease Transmission Advisory Committee

Donor‐derived disease transmission is increasingly recognized as a source of morbidity and mortality among transplant recipients. Policy 4.7 of the Organ Procurement and Transplantation Network (OPTN) currently requires reporting of donor‐derived events. All potential donor‐derived transmission events (PDDTE) reported to OPTN/UNOS were reviewed by the Disease Transmission Advisory Committee (DTAC). Summary data from January 1, 2005–December 31, 2007, were prepared for presentation. Reports of PDDTE have increased from 7 in 2005, the first full year data were collected, to 60 in 2006 and to 97 in 2007. More detailed information is available for 2007; a classification system for determining likelihood of donor‐derived transmission was utilized. In 2007, there were four proven and one possible donor‐derived malignancy transmissions and four proven, two probable and six possible donor‐derived infectious diseases transmissions. There were nine reported recipient deaths attributable to proven donor transmissions events arising from eight donors during 2007. Although recognized transmission events resulted in significant morbidity and mortality, transmission was reported in only 0.96% of deceased donor donations overall. Improved reporting, through enhanced recognition and communication, will be critical to better estimate the transmission risk of infection and malignancy through organ transplantation.

Characterization of Staphylococcus aureus Isolates from Nasal Cultures Collected from Individuals in the United States in 2001 to 2004

ABSTRACT This study characterizes methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) isolates recovered from nasal cultures of noninstitutionalized individuals in the United States obtained in 2001 to 2004 as part of the National Health and Nutrition Examination Survey. Every tenth MSSA isolate and all MRSA isolates were typed by pulsed-field gel electrophoresis (PFGE), screened for multiple toxin genes, and tested for susceptibility to 14 antimicrobial agents. USA200, USA600, and USA900 were the predominant PFGE types among MSSA isolates in both the 2001 to 2002 and the 2003 to 2004 time periods, although they accounted for only 51.3% of 316 MSSA isolates typed in 2001 and 2002 and only 43.4% of 237 MSSA isolates typed in 2003 and 2004. In contrast, USA100, USA800, and USA700 accounted for 80.0% of the 75 MRSA isolates typed in 2001 and 2002, while USA100, USA800, and USA300 accounted for 78.4% of 134 MRSA isolates typed in 2003 and 2004. The proportion of MRSA isolates that were USA300 increased significantly from the first to the second time period (P = 0.03). Most USA200 isolates (both MSSA and MRSA) carried the gene for toxic shock syndrome toxin; however, carriage of the genes encoding Panton-Valentine leukocidin, while common among MRSA of PFGE type USA300, was rare among MSSA USA300 in both time periods. Most MSSA isolates remained susceptible to all antimicrobial agents except erythromycin (79.1 and 76.0% susceptibilities in the 2001 to 2002 and the 2003 to 2004 periods, respectively). In contrast, the proportions of MRSA isolates that were susceptible to chloramphenicol, clindamycin, and erythromycin were lower in 2003 and 2004 than in 2001 and 2002, although none of these differences was statistically significant.

PHS Guideline for Reducing Human Immunodeficiency Virus, Hepatitis B Virus, and Hepatitis C Virus Transmission Through Organ Transplantation

AND FULL-TEXT SCREENING To identify studies that were (1) relevant to one or more key questions; (2 ) primary research, systematic review, or meta-analysis; (3 ) written in English; and (4 ) inclusive of question-specific criteria DATA EXTRACTION AND SYNTHESIS Data abstracted into evidence tables; individual study quality assessed DRAFT RECOMMENDATIONS GRADE of evidence base evaluated, narrative summaries drafted, recommendations drafted from summaries, and recommendation strength assigned FINALIZE RECOMMENDATIONS Recommendations finalized; guideline published Figure 8. Evidence-based process used to develop guideline recommendations for reducing HIV, HBV, and HCV transmission through organ transplantation HIV 5 human immunodeficiency virus HBV 5 hepatitis B virus HCV 5 hepatitis C virus GRADE 5 Grading of Recommendations Assessment, Development, and Evaluation

Update: Interim Guidance for Health Care Providers Caring for Women of Reproductive Age with Possible Zika Virus Exposure — United States, 2016

CDC has updated its interim guidance for U.S. health care providers caring for women of reproductive age with possible Zika virus exposure to include recommendations on counseling women and men with possible Zika virus exposure who are interested in conceiving. This guidance is based on limited available data on persistence of Zika virus RNA in blood and semen. Women who have Zika virus disease should wait at least 8 weeks after symptom onset to attempt conception, and men with Zika virus disease should wait at least 6 months after symptom onset to attempt conception. Women and men with possible exposure to Zika virus but without clinical illness consistent with Zika virus disease should wait at least 8 weeks after exposure to attempt conception. Possible exposure to Zika virus is defined as travel to or residence in an area of active Zika virus transmission ( http://www.cdc.gov/zika/geo/active-countries.html), or sex (vaginal intercourse, anal intercourse, or fellatio) without a condom with a man who traveled to or resided in an area of active transmission. Women and men who reside in areas of active Zika virus transmission should talk with their health care provider about attempting conception. This guidance also provides updated recommendations on testing of pregnant women with possible Zika virus exposure. These recommendations will be updated when additional data become available.