A collection of 2,209 isolates of six polysaccharide capsule types of Haemophilus influenzae, including 1,975 serotype b isolates recovered in 30 countries was characterized for electrophoretically demonstrable allele profiles at 17 metabolic enzyme loci. Two hundred eighty distinct multilocus genotypes were distinguished, and cluster analysis revealed two primary phylogenetic divisions. The population structure of encapsulated H. influenzae is clonal. Currently, most of the invasive disease worldwide is caused by serotype b strains of nine clones. Strains producing serotype c, e, and f capsules belong to single divisions and have no close genetic relationships to strains of other serotypes. Serotype a and b strains occur in both primary phylogenetic divisions, probably as a result of transfer and recombination of serotype-specific sequences of the cap region between clonal lineages. A close genetic relatedness between serotype d isolates and some strains of serotypes a and b was identified. There are strong patterns of geographic variation, on an intercontinental scale, in both the extent of genetic diversity and the clonal composition of populations of encapsulated strains. The analysis suggests that the present distribution of clones is, in part, related to patterns of racial or ethnic differentiation and historical demographic movements of the human host populations.

Alleles↗

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Risk factors for infection in women undergoing testing for Chlamydia trachomatis and Neisseria gonorrhoeae in Manitoba, Canada.

BACKGROUND AND OBJECTIVES: Despite sharing common modes of transmission, characteristics of individuals infected with Chlamydia trachomatis differ in several respects from those with Neisseria gonorrhoeae infection. Further characterization of women at high risk for chlamydial infection is needed to deliver appropriate and effective preventive, diagnostic, and therapeutic care to this population. GOAL OF THIS STUDY: The demographic and socioeconomic characteristics of women with laboratory confirmed chlamydia, gonorrhea, or coinfection were compared with those of control women who tested negative for both pathogens. STUDY DESIGN: A random sample of 400 women in Manitoba, Canada, who had undergone testing for sexually transmitted diseases at a public health laboratory in 1988 were studied. After linkage with medical insurance and census databases, logistic regression analysis was used to compare age, ethnicity, urban status, and mean income (using postal codes) of women with gonorrhea alone, chlamydia alone, and coinfection, with the same data for women who tested negative for both organisms. RESULTS: Young age, North American Indian status, urban residence, and low mean income according to postal code were significantly associated with gonococcal and chlamydial infection in the study population, compared with women who tested negative for both infections. Young age, Indian status, and urban residence also were associated with gonorrhea infection alone. Only young age and Indian status were associated with chlamydial infection. Mean incomes of women with chlamydial infection alone and control subjects were higher than those of women with gonorrhea and gonorrhea and chlamydia coinfection. CONCLUSIONS: Differences in the demographic and socioeconomic characteristics of women with gonorrhea, chlamydia, and coinfection suggest the existence of multiple reservoirs of infection due to these agents in the study population. The preventive, diagnostic, and therapeutic strategies of sexually transmitted disease control programs must be adapted to the individual needs of identified high-risk groups.

Adolescent↗

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Predictors of operative mortality for coronary bypass grafting in patients with ischemic heart disease.

Predictors for operative mortality (OM) were studied in 172 consecutive patients (pts) undergoing coronary artery grafts (CAG) for angina pectoris.Seventy eight pts had Class IV angina; of the 147 patients given propranolol, 41 were gradually withdrawn from propranolol and finally discontinued 24 hours before surgery, and 106 were abruptly withdrawn from propranolol 24 hours before CAG; 20 pts had left main coronary disease; 156 pts had cardiopulmonary bypass (CPB) time shorter than 20 minutes, and 16 pts had a CPB longer than 120 minutes.The operative mortality was 5.2% (9/172) for the entire group. Class IV angina (OM 7%), abrupt propranolol withdrawal (OM 6.6%), left main coronary artery disease (OM 25%), and CPB longer than 120 minutes (OM 50%), all significantly increased OM. These variables were interdependent, however, as many pts belonged to several predictor categories, combinations of predictors were examined, in order to more accurately predict the risk of individual pts. The combination of left main coronary artery disease and CPB longer than 120 minutes; and Class IV angina and CPB longer than 120 minutes were significantly associated with higher operative mortality.We conclude that Class IV angina, abrupt propranolol withdrawal, left main coronary artery disease and prolonged CPB are potent, interdependent predictors of OM in pts undergoing CAG. Consideration of these predictors, alone and in combination, allows effective prediction of OM for CAG in patients with stable angina pectoris.

Adult↗

PubMedDate not supplied