Applications of bacteriocin-like inhibitory substance (BLIS) typing in a longitudinal study of the oral carriage of beta-haemolytic streptococci by a group of Dunedin schoolchildren.
A longitudinal study of the distribution of oral beta-haemolytic streptococci in 103 children (ages 5-6 y) attending three Dunedin schools was initiated in February 1987. A total of 858 paired pharyngeal and saliva specimens were obtained in nine principal sampling sessions, the last being in May 1989. The detection rate of Lancefield group A streptococci in directly plated pharyngeal cultures (19.8%) was considerably higher than in the corresponding saliva cultures (5.1%). By contrast, Lancefield group F and serologically non-groupable beta-haemolytic Streptococcus anginosus tended to be more prevalent in saliva (10.9% positive) than in pharyngeal specimens (7.1%). Group A streptococci were recovered at least once from 59 (57.3%) of the subjects. Representative beta-haemolytic streptococcus isolates were typed according to their production of bacteriocin-like inhibitory substances (BLIS) and by traditional serological techniques. The epidemiological value of BLIS typing was particularly evident in that both BLIS-positive and BLIS-negative strains could be differentiated within serotypes M1, M12 and M22 and also the serologically not typable group A streptococcus isolates. Ten children consistently had small numbers of group A streptococci present in their pharyngeal cultures, for periods of at least 12 months. In six of these subjects the carried strain was M-type 4/BLIS-type 655. This study has shown that in young schoolchildren long-term carriage of a variety of species of beta-haemolytic streptococci with little associated clinical evidence of infection may be common.
Ragland
N
N
Department of Microbiology, University of Otago, Dunedin, New Zealand.
Tagg
J
J
D015373:Bacterial Typing Techniques; D001430:Bacteriocins / Q000096:biosynthesis*; D002353:Carrier State / Q000382:microbiology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D010614:Pharynx / Q000382:microbiology; D012463:Saliva / Q000382:microbiology; D013290:Streptococcal Infections / Q000382:microbiology*; D013291:Streptococcus / Q000145:classification* / Q000302:isolation & purification / Q000378:metabolism
D001430:Bacteriocins