Complete Genome Sequence of Human Coronavirus OC43 Isolated from Mexico.

We report the complete genome sequence of the first Mexican human coronavirus (HCoV) OC43, obtained by new-generation sequencing and a metagenomic approach, isolated from a child hospitalized with pneumonia. The genome is closely related to the other OC43 genome sequences available, ranging from 99.8% to 98.2% nucleotide sequence identity.

Opsonization of T1M1 group A Streptococcus: dynamics of antibody production and strain specificity.

A chemiluminescence method was used to study opsonization of group A Streptococcus (GAS) of serotype T1M1 in serum samples ("sera") obtained from Swedish patients with invasive and noninvasive GAS infection and from healthy blood donors. Acute-phase serum samples ("acute sera") generally demonstrated low ability to opsonize the patient's own GAS isolate, regardless of clinical manifestation. Only approximately 15% of serum samples obtained from healthy blood donors demonstrated high opsonic activity against a standard T1M1 strain. Opsonization of 62 T1M1 isolates (obtained during 1980-1998) by a single immune serum sample showed considerable variation; this indicates that high opsonic immunity may develop only against the infecting isolate or identical clones. T1M1 GAS isolated from 1987 through 1990 were better opsonized by the immune serum sample than were isolates obtained before 1987 or after 1990, a finding that suggests a temporal change of the surface properties that affect opsonization.

[Socioeconomic strata as a predictor factor for constant condom use among adolescents]. / El estrato socioeconómico como factor predictor del uso constante de condón en adolescentes.

INTRODUCTION: Socioeconomic level plays an important role in health inequalities. In Mexico, the highest prevalence of AIDS cases is among individuals of lower socioeconomic level. The purpose of the study was to describe the socioeconomic level (adjusted for psychosocial, situational and demographic variables) as a predictor factor for the consistent condom use among adolescents of Guadalajara, Mexico. METHODS: A sample of 1,410 adolescents, aged 15 to 19 years, drawn from a previous survey stratified by age, gender and socioeconomic strata was included in the study. Analysis was performed in 251 adolescents who reported sexual activity. Statistical analysis was performed using Chi-square, t-test, ANOVA, and logistic regression. RESULTS: The frequency of consistent condom use was 30.7% and there was a prevalence of irregular use. The highest social level was the main predictor (OR= 11.1, CI 95%=2.6-47.6). Others significant predictors were male gender, peer support and better knowledge about HIV/AIDS. CONCLUSION: Socioeconomic level is an important predictor factor for consistent condom use.

Variable susceptibility to opsonophagocytosis of group A streptococcus M-1 strains by human immune sera.

Immunity to group A streptococci (GAS) is thought to be related to the acquisition of type-specific antibody directed against the M protein. However, recent work suggests that immunity may only be strain and not M-type specific. Therefore, susceptibility of 70 different GAS M-1 strains to opsonization and killing by convalescent sera was compared by using a highly sensitive chemiluminescence assay and by standard bactericidal assay. Sequencing of the emm1 gene in 10 strains with variable susceptibility to opsonization revealed 100% homology in 9 strains. Several substitutions in the N-terminal and 2 in the A3 repeat regions of strain CS-190 were associated with profound resistance to opsonization. Thus amino acid substitutions within different regions of the M-1 protein molecule may adversely affect opsonization by immune sera. In addition, non-M protein factors from identical M types influence susceptibility to phagocytosis. These findings may in part explain the persistently high prevalence of M-1 strains worldwide over the last 15 years.

Outer membrane protein profiles of paired nasopharyngeal and middle ear isolates of nontypable Haemophilus influenzae from Mexican children with acute otitis media.

We studied nontypable Haemophilus influenzae (NTHi) isolates from simultaneous cultures of nasopharyngeal exudates (NEs) and middle ear fluids (MEFs) obtained by tympanocentesis from 57 children with acute otitis media (AOM). Preparations of outer membrane proteins (OMPs) from 14 pairs of NTHi strains recovered from NEs and MEFs from 10 children with unilateral AOM and four with bilateral AOM were subjected to sodium dodecyl sulfate polyacrylamide gel electrophoresis. The NTHi subtypes were determined by comparing the OMP profiles of the isolated strains with those of eight reference NTHi subtypes. Of the 14 pairs, 10 (71%) were identical, and one (8%) was different; three strains isolated from NEs (21%) did not correspond to any of the reference subtypes (nonsubtypable). Subtypes 4, 6, 5, 3, and 8 were isolated in the present study, thereby showing that their distribution is similar to that of subtypes isolated from children with AOM in the United States and suggesting that common otogenic strains are widely distributed in North America.

Otitis media today: a challenge for physicians and the community.

Acute otitis media is one of the most common causes of medical consultation worldwide, and has a high economic impact. In this review, a clear definition between acute otitis media and otitis media with effusion is presented. The microbiology and characterization of the main bacterial isolates in acute otitis media and the susceptibility patterns are reviewed, and the latest concepts in antimicrobial treatment are discussed. The need for courses that improve the capability of primary care physicians to diagnose acute otitis media using pneumatic otoscopy, and for parental education is also discussed.

[Sources of information and their relationship to the degree of knowledge about AIDS in Mexican adolescents]. / Fuentes de información y su relación con el grado de conocimientos sobre el SIDA en adolescentes de México.

INTRODUCTION: In Mexico 2.1% of the cases of AIDS are in adolescents. The cases of AIDS in the age group of 20 to 29 account for 30.5% of all the cases and an important proportion could have been infected with HIV in their adolescence, in view of the length of the incubation period from the infection with HIV to the manifestation of the syndrome. The adolescent's knowledge of HIV/AIDS varies. In some urban contexts the adolescents have lay concepts and myths that could guide them into misting practices that could lead to contamination by HIV. The mass media, especially television, and interpersonal sources such as teachers, parents and peers are important sources of information about HIV/AIDS and have a central role in the social construction and public perception of the problem in adolescents. The objective of the study is to relate the degree of knowledge of HIV/AIDS to the exposure to information sources among adolescents in Guadalajara city, in Mexico. MATERIAL AND METHOD: Survey sample with autoapplied questionnaire. Sample of 1,410 adolescents, male and female, of 15 to 19 years of age, in the four socioeconomic strata. The Chi-square and BTukey tests, 95% confidence interval for proportions and means, and simple ANOVA factor were applied. RESULTS: A considerate degree of knowledge (mean of 13.94 correct answer out of 24, standard deviation = 4.09, 95% CI = 13.69-14.11) was found significant mean differences in favor of the high (15.70) and medium (14.26) strata as opposed to the low (13.51) and marginalized (12.85) (F = 19.39, p < .0001, BTukey level .050). The information published by the newspapers (F = 11.1; p < .001) and the teachers (F = 3.72; p < .05) had a direct relationship to the degree of knowledge imported by the daily exposure to the television and other social demographic variables. CONCLUSIONS: The results describe the presence of inequalities by socioeconomic strata in the list of sources in information and the levels of knowledge about HIV/AIDS. It is necessary to strengthen and develop educational action and the publication of messages through the media, institutions and interpersonal networks, with emphasis on interpersonal and media sources available to the low and marginalized strata, and at the same time, to strengthen the action of sources of information available to the other socioeconomic strata.

PIP: 1410 adolescents aged 15-19 years, of both sexes and of varying socioeconomic strata in Guadalajara, completed anonymous self-administered questionnaires concerning their sources of information and knowledge of HIV/AIDS. The objective was to determine the relation between sources of information and degree of knowledge to guide future information campaigns. 95% of the adolescents knew about AIDS. 79% received information from television, 39% from radio, 26% from magazines, and 16% from newspapers. The media identified as the most important sources of information on AIDS were television (60%), and newspapers and magazines (25% each). Except for television, access to the mass media was greater in the high and medium socioeconomic strata. Interpersonal sources of information on HIV/AIDS included teachers for 39%, family members for 38%, friends for 32%, and physicians for 26%. Access to information through interpersonal means was always higher in higher strata. The adolescents had a fair degree of knowledge of AIDS, averaging 13.9 correct answers out of 24 questions. The average numbers correct were 15.7 in the high, 14.3 in the medium, 13.5 in the low, and 12.9 in the marginal strata. Analysis of variance demonstrated that newspapers were the only mass source of information presenting direct positive relation with level of knowledge. Among interpersonal relations, information from teachers had the greatest positive association with level of knowledge.

[Sexual subcultures and degree of risk for acquiring HIV in adolescents in a marginal neighborhood]. / Subculturas sexuales y grado de riesgo de adquisición del VIH en adolescentes de un barrio marginado.

OBJECTIVE: To describe the sexual subcultures and the risk of acquiring HIV among adolescents in Guadalajara, Jalisco MATERIAL AND METHODS: The study took place during August 1994. A cross-sectional study design was used; data collection was done using pile sorts of 20 males and 20 females aged between 15 and 19 years. Data analysis was done by means of hierarchical clustering, multidimensional scaling, cultural consensus and correspondence techniques. RESULTS: Males: this cluster presented a sexual subculture pattern of free expression associated to high risk behaviors. Females: this cluster showed a sexual subculture pattern of celibacy, associated to low risk. Correspondence analysis: a correlation was found among adolescents between their sexual subcultures and risk of acquiring HIV. CONCLUSIONS: Among males, the free expression sexual subculture included high risk sexual behavior for acquiring HIV. Among females, the celibacy sexual subculture included low risk sexual behavior. Nevertheless, both males and females presented high risk sexual behaviors, since they engage in unprotected sexual practices.

[Prevalence of Haemophilus influenzae carrier state in children in Ciudad Nezahualcóyotl, State of Mexico, Mexico]. / Prevalencia de estado de portador de Haemophilus influenzae en niños de Ciudad Nezahualcóyotl, estado de México, México.

OBJECTIVE: To determine the prevalence of H. influenzae (Hi) carrier state among children, in Ciudad Nezahualcóyotl, State of Mexico. MATERIAL AND METHODS: A cross-sectional comparative random study was designed. Study subjects were 639 children under 15 years of age, stratified by age and sex. Nasopharyngeal cultures were used to identify Hi and to typify encapsulated strains. Sample size was computed with the software package Epi-Info, using a p value of 0.5%, 95% confidence intervals and a 5% error; statistical analysis was performed using frequencies, means and proportions. Differences were tested by comparison of two proportions from independent populations. RESULTS: Hi was isolated from 136 of 639 pharyngeal cultures (21%). Hi types found were Hi b (n = 6, 4%), Hi a, c, and f (n = 5, 4%), and non-typifiable (NT) Hi (n = 125, 92%). CONCLUSIONS: The prevalence of pharyngeal colonization by Hi found among children under 15 years of age, in Ciudad Nezahualcóyotl, is similar to that reported in the literature. The inverse relation of pharyngeal carriers with age can be accounted for by the progressive development of specific and non-specific immunity against encapsulated and non-encapsulated strains.

[The impact of Haemophilus influenzae infections on Mexican children]. / Impacto de las infecciones por Haemophilus influenzae en niños mexicanos.

A review of Haemophilus influenzae (Hi) infections in Mexico over the past 32 years was conducted. The proportion of Hi isolates in relation to positive cultures for distinct diseases was distributed as follows for meningitis (9-69%) and for pneumonia with empyema (6-28%). There was no difference in the proportion of Hi isolation between under developed countries and the United States. In other diseases such as septic arthritis, epiglottitis, acute otitis media, acute maxillary sinusitis and in the nasopharyngeal carrier state, the information was too limited. The incidence of Hib invasive disease has been almost eliminated in some areas of the world related to the use of Hib conjugated vaccine. It is imperative for the practitioner to be aware of the advantages of Hib vaccine in infancy.