Acquisition, carriage, and transmission of pneumococci with decreased antibiotic susceptibility in young children attending a day care facility in southern Israel.

The prevalence and transmission of antimicrobial drug-resistant pneumococci was studied in 48 children attending a day care facility in southern Israel. Nasopharyngeal cultures were obtained every 2 weeks for 10 months, and antibiotic susceptibility of isolates was determined by disk diffusion and E-test. Relatedness of isolates was investigated by capsular typing, ribotyping, and arbitrarily primed polymerase chain reaction. Pneumococci were recovered during 362 (63%) of 573 fortnights, and 219 (60%) of these isolates showed decreased susceptibility to at least one drug; 154 (43%) were intermediately susceptible to penicillin and 51 (14%) were multiresistant. Combining the different typing methods showed that a limited number of clones circulated in the facility. Clones exhibiting decreased antibiotic susceptibility (especially 23F, intermediately susceptible to penicillin and resistant to trimethoprim-sulfamethoxazole, and multiresistant 6B) were more frequently isolated and persisted longer than did fully susceptible clones. By multivariate analysis, carriage of organisms with decreased antibiotic susceptibility was associated with young age, female sex, winter season, and exposure to antimicrobial drugs during the previous month.

Respiratory carriage of Kingella kingae among healthy children.

The role of Kingella kingae as an invasive pathogen of young children is being increasingly recognized, but the niche of the organism in the respiratory tract and its prevalence in the normal flora of children remain unknown. To investigate these two aspects throat and nasopharyngeal cultures were obtained every 2 weeks from two cohorts of children, ages 6 to 42 months on enrollment, attending a day-care center in southern Israel. To determine the age-related prevalence of K. kingae, throat cultures were obtained from children ages 6 months to 14 years hospitalized for elective surgery who had not received antibiotics during the previous 30 days and from healthy infants younger than 6 months attending a well-baby-care clinic for routine vaccinations. During an 11-month follow-up 109 of 624 (27.5%) throat cultures but none of the nasopharyngeal cultures obtained from 48 day-care center attendees grew K. kingae. The monthly prevalence of K. kingae ranged from 6.1 to 34.6% with December and April peaks. Overall 35 of 48 (72.9%) children had at least one positive culture for the organism. Among the 27 children who had > or = 2 positive cultures, continuous and intermittent patterns of carriage were observed. None of the colonized children experienced an invasive K. kingae infection. The prevalence of pharyngeal carriage among surgical patients was 8.0%, and the organism was not isolated from any of the infants younger than 6 months attending the well-baby-care clinic.

Evaluation of novel vancomycin-containing medium for primary isolation of Kingella kingae from upper respiratory tract specimens.

A new selective medium (BAV), consisting of trypticase agar with 5% sheep hemoglobin and 2 micrograms of vancomycin per ml, was compared with the routine blood-agar medium for the primary isolation of Kingella kingae from upper respiratory specimens from a population of young children. Infection was detected by the BAV medium in 43 of 44 (98%) cultures positive for K. kingae, and detection of the organism was facilitated by inhibition of gram-positive flora. Infection was detected in only 10 of 44 (23%) positive cultures by the blood-agar medium, and plates were usually covered by abundant normal flora, making the recognition of K. kingae much more difficult. Challenge of the medium with different organisms of respiratory origin showed that the BAV medium was inhibitory for gram-positive cocci and Haemophilus influenzae but that it supported growth of eight K. kingae strains isolated from patients with invasive infections. The new medium appears to be a useful epidemiological tool for studying the respiratory carriage of K. kingae.