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

OBJECTIVETo understand the distribution of emm gene types related to group A streptococcus-caused scarlet fever among children in Beijing and to analyze the relationship between the mutation of the emm types and scarlet fever.

METHODSNasopharyngeal swab samples were collected from the scarlet fever cases diagnosed in 36 hospitals in Beijing to isolate the GAS strains from May to July, betgween 2011 and 2014. Genotyping of emm gene was performed with PCR and N-terminal gene fragments of M protein were sequenced. Data of all the scarlet fever cases in Beijing that reported through the National Notifiable Infectious Disease Surveillance System (NNIDSS) , were gathered and analyzed.

RESULTSAmong the collected 2 161 nasopharyngeal swabs, 762 GAS strains were identified (35.3%). In addition, 7 emm types were detected, in which emm12 accounted for 69.4% (529/762) , emm1 accounted for 29.8% (227/762) , and other five types (emm 11, 22, 75, 89, and 128) accounted for 0.8% (6/762) , respctively. Compared with the emm types detected between 2011 and 2014, emm12, emm1 and other types accounted for 82.2% (295/359) , 16.7% (60/359) and 1.1% (4/359, including emm11, 22 and 89) in 2011 respectively.emm12, emm1 and emm75 accounted for 77.3% (123/163) , 23.9% (39/163) and 0.6% (1/163) respectively in 2012. emm12 and emm1 accounted for 50.7% (38/75) and 49.3% (37/75) in 2013 while emm12, emm1 and emm128 accounted for 44.2% (73/165) , 55.2% (91/165) and 0.6% (1/165) respectively in 2014. The differences of the constitution of emm types from 2011 to 2014 appeared statistically significant (P<0.001). In 2011 and 2012, major type appeared as emm12, but in 2014, emm1 became predominant. A total of 6 152 cases were reported in 2011, while 2 908, 2 048 and 3 918 cases were reported in 2012, 2013 and 2014 respectively. Age specific differences were noticed in the distribution of emm types GAS strains in 2011, with the number of emm12 strains detected higher in 1-5 year olds than in age group > 5 years (P<0.05). There were area specific differences in distribution of emm types of GAS strains seen in 2011 and 2013. In 2011, the number of emm1 strains detected in urban area was higher than in suburb area (P<0.05). However, in 2013, the number of emm1 strains detected in suburb area was seen higher than in urban area (P< 0.05).

CONCLUSIONGAS with emm12 and GAS emm1 appeared interchangeably predominant in Beijing from 2011 to 2014. Changes in predominant emm types seemed also related to the trends of incidence rates on scarlet fever.

Antigens, Bacterial ; Bacterial Outer Membrane Proteins ; Beijing ; epidemiology ; Carrier Proteins ; Child ; Genotype ; Humans ; Mutation ; Scarlet Fever ; epidemiology ; genetics ; Streptococcus pyogenes ; classification ; genetics ; isolation & purification

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