摘要:

The increasing prevalence of intermediately and highly penicillin-resistant strains ofStreptococcus pneumoniaeis a problem worldwide. However, optimal management of patients with middle ear and sinus infections caused by resistant pneumococci has not been established. We performed agar dilution susceptibility studies on 71 strains of penicillin-resistant pneumococci (minimum inhibitory concentration (MIC), ≥0.1 μg/ml) recovered from middle ear and sinus cultures of Houston children against 13 oral antibiotics with the use of both established and newly proposed National Committee for Clinical Laboratory Standards susceptibility criteria. Of the 62 middle ear isolates 35 (56%) were intermediately resistant and 27 (44%) were highly resistant to penicillin. Of the 9 sinus isolates tested, 5 (56%) were intermediately resistant (MIC between 0.1 and 1 μg/ml) and 4 (44%) were highly resistant (MIC ≥2 μg/ml) to penicillin. The MIC90increased with increasing penicillin resistance for the antibiotics tested except for rifampin, ciprofloxacin, loracarbef, clindamycin and trimethoprim-sulfamethoxazole. None of the highly penicillin-resistant isolates was susceptible to loracarbef or trimethoprim-sulfamethoxazole. The MIC90values for clindamycin and rifampin were similar for the intermediately and highly penicillin-resistant groups, and the number of susceptible isolates in each group remained greater than 90% for both antibiotics. Thirty-five isolates were resistant to erythromycin but susceptible to clindamycin, a susceptibility pattern distinctly different from that seen in South Africa and Europe, where clindamycin resistance parallels erythromycin resistance. Further study is necessary to correlatein vitrosusceptibility data with clinical outcome from infections caused by penicillin-resistant pneumococci because the MIC90values for most of the antibiotics tested against the isolates in our study exceeded achievable antibiotic concentrations in middle ear effusions.

ISSN:0891-3668    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

In a randomized double blind placebo-controlled study, the rhesus-human reassortant tettravalent oral rotavirus vaccine (dose 4 x 104plaque-forming units) was evaluated in Thai infants immunized at ages 2, 4 and 6 months. To investigate dose responses and to compare vaccine-induced and naturally acquired rotavirus immunity in the study population blood specimens were collected before and 1 month after each vaccination and at 12 months of age. No adverse reactions attributable to the vaccine were detected in the vaccinees. Sixty-three of 94 (67%) vaccine recipients showed a seroconversion in rotavirus IgA anzyme-linked immunosorbent assay antibodies after one or more doses, whereas only 15 of 93 (16%) placebovaccinated control children showed an IgA enzyme-linked immunosorbent assay antibody response, suggestive of natural rotavirus infection, between 2 and 7 months of age. By measuring rhesus rotavirus-neutralizing antibodies a seroconversion was detected in 49% of the vaccinees and 14% of the controls between 2 and 7 months of age. The geometric mean titers of neutralizing antibodies to human rotavirus serotypes 1, 2, 3 and 4 after the completion of vaccinations and at 12 months of age were higher in the vaccinees than in the controls. It is concluded that, even though maternally acquired rotavirus antibodies are commonly present, the rhesus-human reassortant tetravalent vaccine is immunogenic in many Thai infants ages 2 to 6 months. The immunogenicity of this vaccine is enhanced by multiple doses.

ISSN:0891-3668    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

The proportion ofShigellainfections that occur asymptomatically in young children has not been established. A community-based cohort study of 367 infants was followed prospectively by weekly home visits from January, 1990, through December, 1991. Stool samples were collected weekly and when diarrhea occurred and were tested forShigellaand other enteropathogens. There were 2925 child months of observation and 65 episodes ofShigellainfection. There were 3.1 episodes/100 child months during the warm season (May through September) and 0.97 episode/100 child months during the cold season.Shigellainfections were rare during the first 6 months of life but increased with age (P< 0.0001). Overall 55% of detected infections were asymptomatic. The proportion of infections that were asymptomatic increased as age increased (P< 0.01). Symptom status was not significantly associated withShigellaspecies or season. All isolates from symptomatic and asymptomatic children had the 120− to 140− megadalton virulence plasmid. We conclude that infections with virulent strains ofShigellaare commonly asymptomatic in Mexican children during the first 2 years of life.

ISSN:0891-3668    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Breast-feeding plays a potentially significant role in mother to child transmission of human immunodeficiency virus type 1 (HIV-1). The additional transmission risk attributable to breast-feeding and the factors that enhance or inhibit transmission are presently unknown. One mechanism by which breast milk might inhibit HIV-1 transmission is th presence of specific antibodies directed against HIV-1 in breast milk of seropositive mothers. In this study serum and breast milk samples from women in Nairobi, Kenya, were tested to determine the prevalence of HIV-1 IgA antibodies. A Western blot test developed in our laboratory was used to detect anti-HIV-1 immunoglobulin A in serum and anti-HIV-1 secretory IgA (sIgA) in breast milk. Ninety-four percent of 63 HIV-1 seropositive women had anti-HIV-1 IgA in serum and 59% had anti-HIV-1 sIgA in their breast milk. No significant associations with maternal characteristics or srum anti-HIV-1 IgA or IgG banding patterns and the presence of anti-HIV-1 sIgA in breast milk were found. No protective effect of anti-HIV-1 sIgA was seen regarding mother to child transmission; however, further studies are necessary to determine the effect of these antibodies in maternal sera or in breast milk on the efficacy of HIV-1 transmission.

ISSN:0891-3668    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Antimicrobial susceptibility was determined for strains ofStreptococcus pneumoniae, nontypableHaemophilus influenzaeandMoraxella catarrhalisrecovered from the nasopharynxes of children followed from birth. The bacteria tested were the first potential pathogens isolated from each child before any treatment with antibiotics. Minimal inhibitory concentrations of commonly used oral antibiotics demostrated the following overall rates of resistance for (1)S. pneumoniae: penicillin 1.2% (intermediate susceptibility 4.8%), trimethoprim-sulfamethoxazole 20%; (2) nontypableH. influenzae: ampicillin 32%, cefaclor 17%; (3)M. catarrhalis: ampicillin 90%, trimethoprim-sulfamethoxazole 19%. Antibiotic regimens used for treatment of otitis media may have to be evaluated in light of changing antibiotic susceptibilities.

ISSN:0891-3668    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

This study analyzed the interleukin 6 (IL-6) response in 114 children with suspected urinary tract infection (UTI). Urine and serum samples were obtained at the time of enrollment. There were 90 children with UTI, 41 with and 49 without a temperature ≥38.5°C. The remaining 24 children did not have bacteriuria; 11 were febrile and 13 were not. The urinary IL-6 concentrations were higher in the children with UTI (mean, 129 units/ml) than in the children without bacteriuria (mean, 7 units/ml,P< 0.01). In contrast the serum IL-6 did not differ between children with or without UTI or between children with or without a temperature ≥38.5°C. The urinary IL-6 response was higher in children who were infected with P fimbriatedEscherichia colithan in other children with UTI (P< 0.05). There was a correlation of urinary IL-6 with the degree of proteinuria, hematuria and urinary leukocyte counts (P< 0.001,P< 0.05,P< 0.05, respectively) but not with serum IL-6, CRP or temperature, and of serum IL-6 to C-reactive protein (P= 0.053) and renal concentrating capacity (P< 0.05). The results demonstrate that infections of the urinary tract activate an IL-6 response in children and that the magnitude of the IL-6 response is influenced by the properties of the infecting strain.

ISSN:0891-3668    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

To characterize the morbidity of pertussis in Canada, we did a retrospective review of all children with laboratory-confirmed pertussis seen at the Hospital for Sick Children, Toronto, between 1980 and 1990. A total of 975 patients were identified, of which 223 (23%) were admitted to hospital. The peak incidence of disease was observed in the fall. The incidence of disease did not vary with gender. Only 41% of children admitted had the classical symptoms of pertussis (paroxysmal cough and whoop). Compared with children older than 6 months of age, children younger than 6 months of age were more likely to be hospitalized, tended to be hospitalized longer, were less likely to be age-appropriately vaccinated and were more likely to require intensive care unit monitoring. Seventeen (8%) of 223 children required intensive care unit monitoring, and 12 of these children required mechanical ventilation therapy, for a duration of 3.5 ± 0.6 days (mean ± SD). One (0.1%) patient with secondary bacterial pneumonia died. This hospital-based study indicates that pertussis continues to be a cause of serious illness in children, particularly those younger than 6 months of age.

ISSN:0891-3668    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Risk factors for early onset disease (EOD) caused by Group B streptococci (GBS) that are the foundation of prevention guidelines were identified in studies conducted in a few hospital centers. We investigated cases of EOD identified through laboratory-based active surveillance during 1991 and 1992 in a multistate population of 17 million. Ninety-nine cases were compared with 253 controls matched for hospital, date of birth and birth weight. Prematurity (<37 weeks of gestation) was present in 28% of cases; 53% of case mothers had rupture of membranes >12 hours; and 48% reported intrapartum fever. The incidence of EOD in each surveillance area was higher among blacks. By multivariate analysis, case mothers were more likely than controls to have rupture of membranes before labor onset (adjusted odds ratio 8.7,P< 0.001), intrapartum fever (adjusted odds ratio 11.9,P< 0.001), and history of urinary infection during pregnancy (adjusted odds ratio 4.3,P< 0.05). Young maternal age was also associated with risk of disease. Three-fourths of case mothers had intrapartum fever, <37 weeks of gestation and/or prolonged rupture of membranes, indicators previously used to select high risk women for intrapartum chemoprophylaxis. Our findings extend data from single hospitals and suggest prenatal screening and selective intrapartum chemoprophylaxis of high-risk mothers could potentially prevent the majority of EOD in the United States.

ISSN:0891-3668    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Because of the recent resurgence of Group A streptococcal infections and their sequelae and to concerns about Group A streptococcal antimicrobial resistance, 282 isolates from acute pharyngitis and 43 additional isolates from severe, invasive infections were examined for susceptibility to 11 oral antibiotics. M serotypes 1, 2, 3, 4 and 12 accounted for more than one-half of the pharyngeal isolates; M serotypes 1 and 3 accounted for most isolates from severe infections. All 325 isolates were exquisitely susceptible to penicillin (Concentration of antibiotic required to inhibit 90% of isolates, 0.012 μg/ml). Only approximately 4% of the tested strains demonstrated an erythromycin minimum inhibitory concentration of 0.5 μg/ml or greater; the new macrolides, azithromycin and clarithromycin, were similar. The cephalosporins varied somewhat in their ability to inhibit Group A streptococci, but all were effectivein vitro. No major differences in minimum inhibitory concentrate were observed between strains associated with severe infections and those from uncomplicated upper respiratory tract infections. On the basis of the 325 isolates examined, we conclude that antimicrobial resistance has not been a factor in the recent resurgence of Group A infections.

ISSN:0891-3668    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

The safety and immunogenicity of primary immunization at 2, 4 and 6 months of age withHaemophilus influenzaetype b capsular polysaccharide conjugated to tetanus toxoid (PRPT; Act-HIB) were evaluated in infants in Valencia, Venezuela. In order better to assess reactions to PRP-T, subjects received their initial PRP-T vaccine a mean of 6.5 days after their initial diphtheria-tetanus-pertussis (DTP) vaccine. The PRP-T vaccine was well tolerated. Serum was obtained at ages 2 and 7 months (before the first and 1 month after the third PRP-T dose). Antibody responses were compared with those from Nashville infants who had received PRP-T and DTP simultaneously in a previous trial. The preimmunization titers in the Venezuelan and Nashville infants did not differ. The geometric mean postimmunization titer in the Venezuelan infants was 37.9 μg/ml, as compared with 3.63 μg/ml in the Nashville infants (P< 0.00001). Possible explanations for the exceptional antibody response of these Venezuelan infants to PRP-T include carrier priming caused by prior DTP immunization, synergy associated with the specific DTP vaccine used, preimmunization immunologic experience that differed from their United States counterparts and genetic differences that altered response to the vaccines. Further studies are proposed to evaluate these possibilities.

ISSN:0891-3668    

出版商:OVID    

年代:1994

数据来源: OVID