Unnecessary prescribing of antibiotics to healthy/asymptomatic school-age carriers of potentially pathogenic bacteria

Results

A total of 463 NPS’s were collected; from 81 children at the 1st and 2nd visit, 76 children at the 3rd visit, 75 children at the 4th visit, 73 children at the 5th visit, 77 children at the 6th and final visit. Children who were out of school on the date of swab collection were absent for various reasons. Results showed that 83% of included children were HC’s, while 17% (13 children) became ill between visits.

The lowest bacterial colonization was recorded in September, at the first swab collection visit (28% of children colonized by GAS, SP, and Hib), and it increased at each subsequent visit. Colonization by all 3 bacteria peaked at the end of the study, in December (Figure 1A, Figure 1B); 84% of children were colonized by GAS, SP, or Hib (Figure 1B).

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Figure 1

Graph showing the A) colonization of GAS, SP and Hib at each NPS collection visit and the B) combined colonization of GAS, SP and Hib at each NPS collection visit. GAS - Group A Streptococcus, Hib - Haemophilus influenzae type B, NPS - nasopharyngeal swab, SP - Streptococcus pneumoniae

Group A streptococcus, SP, and Hib colonized and recolonized the nasopharynx of each HC at different time intervals. Each child had at least one positive NPS during the study. Most positive swabs had a single bacterium isolated (GAS, SP, or Hib), while 2 different bacteria were isolated from 9 NPS’s, and 3 bacteria in a single NPS (Table 1). Group A streptococcus was the most commonly isolated bacteria at all 6 time points, increasing from 12% at the first visit, to 40% at the final visit. Streptococcus pneumoniae increased from 10% at the first visit, to 27% at the final visit, and Hib increased from 6% at the first visit, to 17% at the final visit (Table 1, Figure 1A).

Before the onset of the disease 7 of 13 children were HC’s: 3 children were GAS carriers, 3 children were SP carriers, and one child was Hib carrier, without showing any clinical signs of disease (Table 2). The same bacteria that were detected before and during the disease were isolated in 3 HC’s, while a different bacteria was isolated in 4 HC’s (Table 2). At the beginning of the illness, a NPS was taken from all of these children at our ENT Clinic. The results showed that all of them had one bacteria in a single NPS and they underwent antibiotic therapy; 6 children had Streptococcal pharyngitis caused by GAS, 4 children had acute otitis media (AOM): 3 AOM caused by SP, one AOM caused by Hib; 3 children had acute tonsillitis/pharyngitis caused by Hib. The duration of antibiotic treatment was determined according to the clinical status of children and the antibiogram. A follow-up NPS taken 5 days after the end of antibiotic therapy showed normal flora (NF) in 8 children, who afterwards rejoined their classes. Group A streptococcus was re-isolated in 3 children who had Streptococcal pharyngitis, SP was re-isolated in 2 children who had AOM. In these children the antibiotic therapy was repeated. A follow-up NPS taken 5 days after the repeated therapy showed NF in all children, and they rejoined their classes (Table 2). At the next planed visit, 5 of 13 re-joined children were again HC’s without showing any clinical symptoms of disease. One bacterium was isolated in a single NPS in 4 children, and 2 different bacteria were isolated in a single NPS from one child. Since the study ended at the final visit, the number of children that potentially started to show symptoms of illness after that time point is unknown.