ABSTRACT
Restriction fragment length polymorphism (RFLP) analysis of IS6110 is commonly used to DNA fingerprint Mycobacterium tuberculosis. However, low-copy (< or =5) IS6110 M. tuberculosis strains are poorly differentiated, requiring secondary typing. When spoligotyping was used as the secondary method, only 13% of Maryland culture-positive tuberculosis (TB) patients with low-copy IS6110-spoligotyped clustered strains had epidemiologic linkages to another patient, compared to 48% of those with high-copy strains clustered by IS6110 alone (P < 0.01). Spoligotyping did not improve a population-based molecular epidemiologic study of recent TB transmission.
Subject(s)
DNA Fingerprinting , DNA Transposable Elements/genetics , Gene Dosage , Mycobacterium tuberculosis/classification , Tuberculosis, Pulmonary/epidemiology , Aged , Bacterial Typing Techniques , Humans , Mycobacterium tuberculosis/genetics , Oligonucleotides/analysis , Polymorphism, Restriction Fragment Length , Tuberculosis, Pulmonary/microbiologyABSTRACT
CONTEXT: Incidence of invasive meningococcal disease has increased recently in persons aged 15 through 24 years. OBJECTIVE: To characterize meningococcal infection in adolescents and young adults in Maryland during the 1990s. DESIGN AND SETTING: Population-based surveillance study for meningococcal disease from January 1, 1990, through December 31, 1999, in Maryland. PATIENTS: Maryland residents diagnosed as having invasive meningococcal disease. MAIN OUTCOME MEASURE: Invasive meningococcal infection. RESULTS: Of 295 total cases, 71 (24.1%) occurred among persons aged 15 through 24 years. Sixteen (22.5%) of these cases were fatal. The annual incidence rate increased from 0.9 to 2.1 cases per 100 000 among 15 through 24 year olds (P =.01). The proportion of all disease increased from 16.0% to 28.9% (P =.03). The incidence and proportion of cases subsequently decreased to 1.0 and 16.4% in 1998 through 1999, respectively. Infection in 15 through 24 year olds was more likely to be fatal than infection in those younger than age 15 years (22.5% vs 4.6%; P =.001). Infection in 15 through 24 year olds, compared with those aged 25 years or older, was more likely to be associated with male sex (66.2% vs 34.8%; P<.001) and serogroup C infection (46.9% vs 20.2%; P<.001), respectively. Infections were potentially preventable with the licensed meningococcal vaccine in 82.8% of 15 through 24 year olds, 68.1% of those younger than 15 years, and 76.8% of adults aged 25 years or older. CONCLUSIONS: Incidence of meningococcal infection in 15 through 24 year olds in Maryland increased and then declined during the 1990s. Infection in this age group was associated with an unusually high case-fatality ratio, and the vast majority of cases were potentially vaccine preventable.
