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Background. Invasive pneumococcal disease (IPD) continues to be a significant burden in children despite the implementation of two generations of conjugate vaccines. Serotype replacement by nonvaccine serotypes is reported in multiple areas around the world. This study is a continuation of previous studies and describes the incidence, serotype distribution, and antibiotic resistance pattern of Streptococcus pneumoniae serotypes causing IPD at Children's Medical Center Dallas after introduction of 13-valent pneumococcal conjugate vaccine (PCV13). Methods. Streptococcus pneumoniae isolates from normally sterile sites were collected from January 1, 1999 to June 30, 2014. Demographic and clinical information was extracted for analysis. Incidence of IPD was calculated using inpatient and emergency center admissions to Children's Medical Center of Dallas as the denominator. Isolates were serotyped and penicillin/cefotaxime susceptibilities were determined. Selected nontypeable isolates were further characterized by multilocus sequence typing. A χ2 test and the Cochran-Armitage Trend Test for trend analysis were used to evaluate change in serotype and antibiotic susceptibility patterns over time. Results. Comparison of the different study periods showed a significant reduction in the incidence of IPD in PCV13 era compared with prevaccine era and PCV7 era (P < .05). Children younger than 24 months showed the largest reduction of disease incidence. More than 40% of patients with IPD had a documented comorbidity. Cases of pneumonia continued to decrease in the PCV13 era (P < .002). The most common non-PCV13 serotypes after vaccine introduction were as follows: 23B, 6C, 23A, 9N/L, and 12. Penicillin resistance by meningitis breakpoint decreased significantly in the PCV13 era. Conclusions. After introduction of PCV13 in Dallas, incidence of IPD caused by strains contained in the vaccine and penicillin resistance continued to decrease. Serotype replacement phenomena and persistence of PCV7 serotypes were documented. Patients with comorbidities represented a large percentage of patients with IPD. Concerns for geographic variation in serotype replacement phenomena arise from the present study. [ABSTRACT FROM AUTHOR]

Background. Studies suggest that the 7-valent pneumococcal conjugate vaccine (PCV7) reduces carriage of vaccine-type (VT) Streptococcus pneumoniae (SP). We studied the effect of PCV7 on carriage of VT- and non-VT (NVT) SP, by studying the effect of PCV7 on nasopharyngeal (NP) colonization by VT and NVT SP during early childhood. Methods. At 2 months of age, 278 infants were enrolled in this study. To determine carriage of SP, NP samples were obtained before each PCV7 dose, at 9 months of age, and 2–3 months after the booster dose of vaccine. Results. The carriage of SP increased slightly, from 12% (95% confidence interval [CI], 8%–16%) of subjects at 2 months of age to 18% (95% CI, 13%–23%) at 4 months of age (P < .05. Carriage of SP remained in 24%– 30% of subjects during subsequent months. Between the 12- and 18-month visits, the carriage rate of VT SP decreased significantly, from 18% (95% CI, 13%–23%) to 9% (95% CI, 5%–13%) of subjects (P = .001) The trend of a decrease in carriage of penicillin-nonsusceptible SP, from 16% of subjects (95% CI, 11%–21%) at the 12–15-month visit to 9% (95% CI, 5%–13%) at the 15–18-month visit, was found after the booster dose of vaccine. Conclusion. The reduction of VT-SP colonization and replacement by NVT SP after the booster dose of vaccine suggests the possibility that widespread vaccination will result in replacement of pneumococci mainly by antibiotic-susceptible NVT SP. [ABSTRACT FROM AUTHOR]

Presents a study which examined the effects of large dosages of amoxicillin/clavulanate or azithromycin on nasopharyngeal carriage of Streptococcus pneumoniae, Haemophilus influenzae, nonpneumococcal alpha -hemolytic streptococci and Staphylococcus aureus in children with acute otitis media. Association of the prior use of antibiotics with carriage of resistant bacteria; Methodology; Results.

A prospective study of 154 consecutive high-risk hospitalized children with lower respiratory infections was conducted to determine the clinical utility of a pneumolysin-based polymerase chain reaction (PCR) assay compared with blood and pleural fluid cultures and serological and urinary antigen tests to determine the incidence of Streptococcus pneumoniae. Whole blood, buffy coat, or plasma samples from 67 children (44%) tested positive by PCR. Sensitivity was 100% among 11 promptly tested culture-confirmed children and specificity was 95% among control subjects. Age, prior oral antibiotic therapy, and pneumococcal nasopha-ryngeal colonization did not influence PCR results, whereas several surrogates of disease severity were associated with positive tests. Although serological and urinary antigen tests had comparable sensitivity, specificity varied among infected children, and statistical agreement among all assays was limited. These findings support the use of PCR tests to evaluate the protective efficacy of pneumococcal conjugate vaccines and to identify promptly children with pretreated or nonbacteremic pneumococcal lower respiratory infections. [ABSTRACT FROM AUTHOR]

Evaluates the effect of antibiotic therapy on nasopharyngeal colonization of Streptococcus pneumoniae and Haemophilus influenzae in children diagnosed with acute otitis media. Eradication or suppression of all strains of S. pneumoniae susceptible to penicillin by amoxicillin/clavulanate therapy; Reduction of carriage of H. influenzae by antimicrobial therapy.

Penicillin V, benzathine/procaine penicillin C, cefadroxil monohydrate, and erythromycin estolate were randomly assigned for therapy of group A streptococcal pharyngitis in 198 children. All patients improved within 24 hours of initiating therapy. Reinfection with a new group A streptococcal serotype occurred in 13 patients, 12 developing 7 to 12 days after stopping therapy and 11 becoming symptomatic. Relapse with the same organism occurred in 16 patients, only 5 (31%) of whom were symptomatic. Antibody titer rises, antibiotic resistance of group A organisms, presence of penicillinase-producing staphylococci, and lack of compliance were not related to recurrent infections. There were no significant differences between the failure rates of the four test drugs: penicillin V, 12%; benzathine/procaine penicillin G, 12%; cefadroxil monohydrate, 5%; and erythromycin, 2%. [ABSTRACT FROM AUTHOR]