Bacterial Typing Techniques ; Genes, Bacterial ; genetics ; Streptococcus pyogenes ; classification ; genetics

To determine the carrier rate of beta-hemolytic streptococci (BHS), throat cultures were taken from healthy elementary school children in four separate areas of Korea from 1992 to 1995, including Inje, Nonsan, Seoul and Chinju. The strains of Streptococcus pyogenes had been serotyped with anti-T, -OF and -M sera. The isolation rates of BHS and S. pyogenes ranged from 14.1-32.4% and 10.9-18.5% respectively. More than half of the carriers showed heavy growth of BHS. M78 (48.6%) and M28 (22.2%) were most common in Inje, M12 (23.6%) and M5 (20.3%) in Nonsan, M12 (48.8%) and M5 (14.6%) in Seoul, and M12 (26.3%) and M22 (14.5%) in Chinju, respectively. About 15% of school children were positive for S. pyogenes in throat cultures, and the distribution of serotypes varied according to geographical regions.
Carrier State ; Child ; Child, Preschool ; Female ; Human ; Male ; Pharynx/microbiology* ; Schools ; Serotyping* ; Streptococcus pyogenes/isolation & purification* ; Streptococcus pyogenes/classification*

Seventy-seven Streptococcus pyogenes strains isolated of children of three elementary schools located in Kangwon-do in spring, 1992 were serotyped with M, opacity factor (OF) and T typing antisera. In the M/OF typing results, M-78 (46.8%) and M-28 (22.1%) were most frequently encountered, while M-4 (6.5%), M-12 (5.2%), M-3 (1.3%), M-5 (1.3%) and M-6 (1.3%) were rarely observed. Twelve strains (15.6%) were not typable with M or OF typing system. In the T typing results, T-11 (35.1%) and T-28 (27.3%) were most common. We were able to identify 77.9% of S. pyogenes strains by T typing, 94.8% with T typing and OF typing. With the addition of M typing, 97.4% were typable. Through the serotypings, we could know the basic distribution of serotypes of S. pyogenes of healthy children which could be comparable to those of rheumatic fever, poststreptococcal glomerulonephritis and other severe streptococcal disease.
Adolescent ; Bacterial Typing Techniques ; Child ; Female ; Humans ; Korea ; Male ; Pharynx/microbiology ; Rheumatic Fever/microbiology ; Serotyping ; Streptococcus pyogenes/*classification/isolation & purification

Serotypings have been used as markers for epidemiological surveys of Streptococcus pyogenes infections. Seventy-seven strains of S. pyogenes isolated from the throats of elementary school children in Kangwon Province in Korea in March and April 1992 were serotyped with M and/or opacity factor (OF) antisera. Sixty-eight strains of S. pyogenes from healthy school children in Chungnam Province in March 1993 were also serotyped and the distribution of serotype was compared with the isolates from those living in Kangwon Province. The distributions of M types were quite different between the two areas. M-78 (46.8%) and M-28 (22.1%) were most frequently encountered in Kangwon Province, while M-5 (20.6%), M-12 (16.2%), M-3 (13.2%), M-1 (11.8%) and M-62 (11.8%) were frequently isolated in Chungnam Province. Eighty-seven percent of strains in Kangwon produced OF while 33.2% of those in Chungnam produced OF (p< 0.0001). The difference in the distribution of serotypes and of OF production in the isolates from the children in the two provinces may be responsible for differences in the epidemiology of group A streptococcal infections and their sequelae.
Child ; Comparative Study ; Human ; Korea/epidemiology ; Residence Characteristics ; Rural Population ; Serotyping ; Streptococcal Infections/epidemiology/*microbiology ; Streptococcus pyogenes/*classification/pathogenicity ; Virulence

OBJECTIVETo explore the distribution characteristics of the types of M protein gene (emm) in group A streptococcus (GAS) isolated from children in Beijing in the year 2011.

METHODSDuring May to July in 2011, a total of 3315 patients who were diagnosed scarlet fever or pharyngeal infection by doctors in pediatric outpatient and emergency units of 36 hospitals, were selected as subjects. Their throat swab samples were collected and isolated the strains of GAS. Gene emm was then amplified and sequenced by PCR method, and the differences in types of gene emm between different populations and diseases were compared.

RESULTSA total of 633 strains of GAS were isolated from the 3315 throat swab samples, 610 strains out of which were gene emm positive and were recruited in the study. Out of the 610 recruited strains, 448 (73.4%) were isolated from scarlet fever patients, the other 162 (26.6%) were isolated from pharyngeal infection patients; 397 (65.1%) were from urban, the other 213 (34.9%) were from suburb; 240 (39.4%) were from patients aging between 1 - 5 years old, the other 369(60.6%) were from patients aging 6 - 18 years old. A total of 8 types of gene emm (scarlet fever: 6 types, pharyngeal infection: 4 types) and 21 subtypes of gene emn (scarlet fever: 16 subtypes, pharyngeal infection: 10 subtypes) were identified. Three new subtypes were found in the study, naming emm1.63, emm12.62 and st5144.20. Among them, emm1.63 was found both in scarlet fever and pharyngeal infection patients, while emm12.62 and st5144. 20 were only found in pharyngeal infection patients. Among all the types of gene-emm, emm12 accounted for the highest percentage as 80.5% (491/610) and then followed by emm1 (18.0% (110/610)). Among all the subtypes, the dominant subtype was emm12.00, accounting for 69.0% (421/610), following by emm1.00 (16.9% (103/610)) and emm12.19 (6.1% (37/610)). All the above types and subtypes of gene emm were the most prevalent strains in scarlet fever patients and pharyngeal infection patients. Significant differences in the distribution of prevalent strains were observed among various aging patients and regions. The constituent ratios of emm1, emm1.00 and emm12.19 were higher in patients from suburb (emm1: 22.1% (47/213), emm1.00: 19.2% (40/213), emm12.19: 8.0% (17/213)) than those in urban areas (emm1: 15.9% (63/397), emm1.00: 15.6% (62/397), emm12.19: 5.0% (20/397)). The difference showed statistical significance (P < 0.05). The constituent ratio of emm1.00 was higher among patients aging 6-18 years old (19.2% (71/369)) than those aging 1 - 5 years old (13.3% (32/240)). The difference also showed statistical significance (χ(2) = 8.45, P < 0.05).

CONCLUSIONAmong the types of gene emm in GAS isolated from children in Beijing in year 2011, the most prevalent two were emm12 and emm1, and the most prevalent emm subtypes were emm12.00, emm1.00 and emm12.19. A significant difference in their distribution between various aging patients and isolated places can be obviously found.

Adolescent ; Antigens, Bacterial ; classification ; genetics ; Bacterial Outer Membrane Proteins ; classification ; genetics ; Carrier Proteins ; classification ; genetics ; Child ; Child, Preschool ; China ; Female ; Genes, Bacterial ; Genotype ; Humans ; Infant ; Male ; Microbial Sensitivity Tests ; Streptococcus pyogenes ; genetics ; isolation & purification