Risk of tuberculosis in correctional healthcare workers

OBJECTIVE: The objective of this study was to determine the prevalence, incidence, and risk factors for occupational infection with tuberculosis among healthcare workers employed in correctional facilities. METHODS: The authors conducted a self-administered survey, clinical interview, and tuberculin skin testing. RESULTS: The overall tuberculin skin test point prevalence rate was 17.7%, the reactivity rate was 2.2%, and the annual incidence was 1.3%. At the multivariate level, after controlling for bacille Calmette-Guérin vaccination, only origin of birth remained significantly associated with prevalence of tuberculosis infection. CONCLUSIONS: Although the prevalence of tuberculin reactivity was high in this population, the risk factors were predominantly demographic rather than occupational. Nevertheless, continued vigilance to control occupational exposure to this and other respiratory pathogens is warranted, given the potential for future outbreaks of tuberculosis, as well as other known and emerging airborne pathogens.     

Community-associated methicillin-resistant Staphylococcus aureus, Minnesota, 2000-2003

We compared characteristics of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) skin and soft tissue infections (SSTIs) and CA-MRSA invasive disease identified in Minnesota from 2000 through 2003. A total of 586 patients with SSTIs and 65 patients with invasive disease were identified. Patients with invasive disease were more likely to be smokers (p = 0.03), and report a history of immunosuppressive therapy (p = 0.03), emphysema (p = 0.011), or injection drug use (p = 0.020) than were SSTI patients. Invasive disease isolates were less likely to be susceptible to ciprofloxacin (p = 0.002) and clindamycin (p = 0.001) and more likely to have healthcare-associated pulsed-field gel electrophoresis subtypes than SSTI isolates (p<0.001). Patients with invasive disease may have had healthcare exposures that put them at risk of acquiring healthcare-associated MRSA and which were not exclusion criteria in the CA-MRSA case definition. Continued surveillance of MRSA is needed to better characterize CA-MRSA infections.     

Control strategies for Q fever based on results of pre-vaccination screening in Victoria, 1988 to 2001

OBJECTIVE: Data from Q fever pre-vaccination screening were analysed to determine the level of agreement between the two tests of immunity and between disease or vaccination history and immunity, trends in proportion of participants immune to Q fever, and the annual risk of infection. METHOD: Data from nearly 10,000 screening episodes between July 1988 and June 2001 on Victorian workers at high risk were assessed. RESULTS: Most participants were male (86%) and employed in Victorian abattoirs (81%). Agreement between results of tests for immunity was 'fair' (kappa=0.52). Self-reported history of vaccination or infection was a poor predictor of immunity. The proportion of positive blood and skin tests increased with years of exposure to animals/meat, but decreased over the 13-year period with shorter exposures. Hence the percentage requiring vaccination increased from 50% in 1998 to 90% in 2001. The average annual risk of infection among abattoir workers was 45.0 per 1,000 (95% CI 42.3-47.6), and 62.6 per 1,000 (95% CI 57.5-67.7) over the first 10 years of exposure. CONCLUSIONS: This is the first Australian study to estimate the annual risk of Q fever infection in abattoir workers. The study confirmed previous findings of poor agreement between screening tests and predictive value of history of vaccination/ exposure. Up to 90% of new entrants in high-risk workplaces will be susceptible to Q fever and require vaccination. IMPLICATIONS: Systematic post-marketing surveillance is needed to monitor adverse events to the vaccine, duration of protection and possible reasons for vaccine failures.     

Predictors of improvement in hemoglobin concentration among toddlers enrolled in the Massachusetts WIC Program

OBJECTIVE: Nutrition supplementation programs are generally targeted to those members of the population who are thought to be at risk of an undesirable outcome, but not all who participate in such programs respond to them. We sought to identify determinants of improvement in hemoglobin concentration among young children in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). DESIGN: We conducted an observational study using data from 9,930 children who were enrolled in the Massachusetts WIC program and had data available on their hemoglobin values at both 1 and 2 years of age. Predictors of change in hemoglobin concentration between these ages were studied using multivariate statistical modeling. RESULTS: Overall, hemoglobin concentrations increased from age 1 to 2 years in those who had been breastfed 25 or more weeks (P < .0001) and were female (P < .01), and decreased with increasing weight at 1 year of age (P < .001). The determinants of change in hemoglobin concentration differed from the determinants of hemoglobin concentration at age 1 year. CONCLUSIONS: The analytical approach used here could be extended to identify subgroups of WIC participants likely to improve in other outcomes. If current efforts to increase the duration of breastfeeding among WIC participants are successful, the importance of WIC in improving hemoglobin concentration among young children also will increase.