Karen Stefonek

Epidemiology of Invasive Group B Streptococcal Disease in the United States, 1999-2005

CONTEXT Group B streptococcus is a leading infectious cause of morbidity in newborns and causes substantial disease in elderly individuals. Guidelines for prevention of perinatal disease through intrapartum chemoprophylaxis were revised in 2002. Candidate vaccines are under development. OBJECTIVE To describe disease trends among populations that might benefit from vaccination and among newborns during a period of evolving prevention strategies. DESIGN AND SETTING Analysis of active, population-based surveillance in 10 states participating in the Active Bacterial Core surveillance/Emerging Infections Program Network. MAIN OUTCOME MEASURES Age- and race-specific incidence of invasive group B streptococcal disease. RESULTS There were 14,573 cases of invasive group B streptococcal disease during 1999-2005, including 1348 deaths. The incidence of invasive group B streptococcal disease among infants from birth through 6 days decreased from 0.47 per 1000 live births in 1999-2001 to 0.34 per 1000 live births in 2003-2005 (P < .001), a relative reduction of 27% (95% confidence interval [CI], 16%-37%). Incidence remained stable among infants aged 7 through 89 days (mean, 0.34 per 1000 live births) and pregnant women (mean, 0.12 per 1000 live births). Among persons aged 15 through 64 years, disease incidence increased from 3.4 per 100,000 population in 1999 to 5.0 per 100,000 in 2005 (chi2(1) for trend, 57; P < .001), a relative increase of 48% (95% CI, 32%-65%). Among adults 65 years or older, incidence increased from 21.5 per 100,000 to 26.0 per 100,000 (chi2(1) for trend, 15; P < .001), a relative increase of 20% (95% CI, 8%-35%). All 4882 isolates tested were susceptible to penicillin, ampicillin, and vancomycin, but 32% and 15% were resistant to erythromycin and clindamycin, respectively. Serotypes Ia, Ib, II, III, and V accounted for 96% of neonatal cases and 88% of adult cases. CONCLUSIONS Among infants from birth through 6 days, the incidence of group B streptococcal disease was lower in 2003-2005 relative to 1999-2001. This reduction coincided with the release of revised disease prevention guidelines in 2002. However, the disease burden in adults is substantial and increased significantly during the study period.

Mortality from invasive pneumococcal pneumonia in the era of antibiotic resistance, 1995-1997.

OBJECTIVES This study examined epidemiologic factors affecting mortality from pneumococcal pneumonia in 1995 through 1997. METHODS Persons residing in a surveillance area who had community-acquired pneumonia requiring hospitalization and Streptococcus pneumoniae isolated from a sterile site were included in the analysis. Factors affecting mortality were evaluated in univariate and multivariate analyses. The number of deaths from pneumococcal pneumonia requiring hospitalization in the United States in 1996 was estimated. RESULTS Of 5837 cases, 12% were fatal. Increased mortality was associated with older age, underlying disease. Asian race, and residence in Toronto/Peel, Ontario. When these factors were controlled for, increased mortality was not associated with resistance to penicillin or cefotaxime. However, when deaths during the first 4 hospital days were excluded, mortality was significantly associated with penicillin minimum inhibitory concentrations of 4.0 or higher and cefotaxime minimum inhibitory concentrations of 2.0 or higher. In 1996, about 7000 to 12,500 deaths occurred in the United States from pneumococcal pneumonia requiring hospitalization. CONCLUSIONS Older age and underlying disease remain the most important factors influencing death from pneumococcal pneumonia. Mortality was not elevated in most infections with beta-lactam-resistant pneumococci.

Increasing Burden of Invasive Group B Streptococcal Disease in Nonpregnant Adults, 1990–2007

BACKGROUND Group B Streptococcus (GBS), traditionally considered to be a neonatal pathogen, is an important cause of morbidity and mortality among older adults and among those with underlying medical conditions. We used population-based surveillance to examine trends in adult GBS disease during the period 1990-2007 and to describe the epidemiology of adult GBS disease to guide prevention efforts. METHODS Active Bacterial Core surveillance was conducted in selected counties in 10 US states. A case was defined as isolation of GBS from a normally sterile site in a nonpregnant resident of a surveillance area who was 18 years of age. Rates were calculated using US Census data. Demographic and clinical information was abstracted from medical records. Serotyping and susceptibility testing were performed on isolates collected from a subset of case patients. RESULTS A total of 19,512 GBS cases were identified in nonpregnant adults during 1990-2007 (median patient age, 63 years); the incidence of adult GBS disease doubled from 3.6 cases per 100,000 persons during 1990 to 7.3 cases per 100,000 persons during 2007 (P < .001). The mean difference in incidence between black and white persons was 4.6 cases per 100,000 persons (range, 3.1 cases per 100,000 persons during 1991 to 5.8 cases per 100,000 persons during 1999). Common clinical syndromes in 2007 included bacteremia without focus (39.3%), skin and/or soft-tissue infection (25.6%), and pneumonia (12.6%). Most (88.0%) GBS cases in adults had 1 underlying condition; diabetes was present in 44.4% of cases. Serotypes V, Ia, II, and III accounted for 80.8% of infections during 1998-1999 and 78.5% of infections during 2005-2006. CONCLUSIONS Invasive GBS disease in nonpregnant adults represents a substantial and increasing burden, particularly among older persons, black persons, and adults with diabetes. Prevention strategies are needed.

Prenatal screening for infectious diseases and opportunities for prevention

OBJECTIVE To characterize adherence with recommendations for prenatal infectious disease screening and missed opportunities for prevention of congenital and perinatal infections. METHODS Demographic, prenatal, and peripartum information was abstracted from labor and delivery records of a random, stratified sample of live births in 1998 and 1999 to residents of eight active surveillance areas. Adherence with prenatal screening recommendations was evaluated for hepatitis B, syphilis, rubella, human immunodeficiency virus (HIV), and group B streptococcus (GBS). Characteristics of missed opportunities for disease prevention were assessed by univariate and multivariable analysis to account for survey design. RESULTS Prenatal screening rates for hepatitis B surface antigen (HBsAg) (96.5%), syphilis (98.2%), and rubella (97.3%) were high. Areas of excess syphilis morbidity did not adhere to recommendations for third-trimester retesting. Testing rates for HIV (57.2%) and GBS (52.0%) were lower and had wide geographic variation. Postpartum rubella vaccination was documented for only 65.7% of rubella-susceptible women. Inadequate prenatal care was the single strongest predictor of missed opportunities for prenatal testing (relative risk 14.6; 95% confidence interval 6.3, 33.7). Blacks were less likely than whites to receive adequate prenatal care and prenatal tests, more likely to test positive for HBsAg and syphilis, and less likely to receive recommended prevention interventions such as postpartum rubella vaccination for susceptible women. CONCLUSIONS Adherence to both long-standing and more recent recommendations for congenital and perinatal disease prevention can be improved, thus perhaps reducing racial disparities in the use of prenatal screening and appropriate prevention interventions.

Risk for Severe Group A Streptococcal Disease among Patients' Household Contacts

From January 1997 to April 1999, we determined attack rates for cases of invasive group A streptococcal (GAS) disease in household contacts of index patients using data from Active Bacterial Core Surveillance sites. Of 680 eligible index-patient households, 525 (77.2%) were enrolled in surveillance. Of 1,514 household contacts surveyed, 127 (8.4%) sought medical care, 24 (1.6%) required hospital care, and none died during the 30-day reference period. One confirmed GAS case in a household contact was reported (attack rate, 66.1/100,000 household contacts). One household contact had severe GAS-compatible illness without confirmed etiology. Our study suggests that subsequent cases of invasive GAS disease can occur, albeit rarely. The risk estimate from this study is important for developing recommendations on the use of chemoprophylaxis for household contacts of persons with invasive GAS disease.

Multistate Shigellosis Outbreak and Commercially Prepared Food, United States

In 2000, shigellosis traced to a commercially prepared dip developed in 406 persons nationwide. An ill employee may have inadvertently contaminated processing equipment. This outbreak demonstrates the vulnerability of the food supply and how infectious organisms can rapidly disseminate through point-source contamination of a widely distributed food item.

Risk Factors for Meningococcal Disease in Students in Grades 9-12

Background: Meningococcal disease is a serious problem in adolescents, including high school students. Universal immunization of adolescents with meningococcal conjugate vaccine was recently recommended. We studied risk factors for meningococcal disease in students in grades 9–12. Methods: This was a matched case-control study using surveillance for meningococcal disease in students in grades 9–12 in sites throughout the United States. For each case-patient, up to 4 controls were selected from the home room classroom. All subjects answered an extensive questionnaire. Logistic regression was performed to identify risk factors associated with meningococcal disease. Meningococcal isolates were characterized. Results: Of 69 eligible patients, 49 (71%) were enrolled and had at least 1 control. Isolates were available for 59 (86%) cases. Attending at least 1 barbeque or picnic [matched odds ratio (MOR): 0.26, P value = 0.003] or school dance (MOR: 0.30, P = 0.04) were independently associated with decreased risk of meningococcal disease. Male gender (MOR: 2.94, P = 0.009), upper respiratory infection symptoms (MOR: 2.43, P = 0.04), marijuana use (MOR: 4.21, P = 0.009), and nightclub/disco attendance (MOR: 3.30, P = 0.04) were associated with increased risk. Among 54 students not from Oregon (where serogroup B strains predominate) with available serogroup, 38 (73.1%) cases were potentially vaccine preventable: 18 (34.6%) serogroup C, 19 (36.5%) serogroup Y, and 1 (1.9%) serogroup W-135. Conclusions: Certain behaviors increase the risk of meningococcal infection, whereas others are associated with decreased risk. Most meningococcal disease in high school students can be prevented if recommendations on use of meningococcal conjugate vaccine are implemented.