M types of group a streptococcal isolates submitted to the National Centre for Streptococcus (Canada) from 1993 to 1999.
The National Centre for Streptococcus (NCS) (Canada) determined the group A streptococcal (GAS) M types of 4,760 Canadian isolates submitted between 1993 and 1999 by classic serotyping. The 10 most frequently identified M types were M1 (26.4%), M12 (9.8%), M28 (8.9%), M3 (6.8%), M4 (6.2%), M11 (4.8%), M89 (3.1%), M6 (3.0%), M2 (2.6%), and M77 (1.9%). Nontypeable isolates accounted for 15.4% of the collection. The province of Ontario submitted 51.1% of the isolates, followed by Quebec (21.2%) and Alberta (13.9%). Together, these three provinces constituted 71.3% of the Canadian population in 1996. The numbers of M types M1, M12, M28, and M3 occurred most frequently in subjects whose ages were <1 to 15 years and 25 to 45 years, as well as in the elderly (60 to 90 years). Further analysis found that the four most frequently identified M types from blood, brain, and cerebrospinal fluid were M1 (28.2%), M28 (9.2%), M12 (9.1%), and M3 (8.2%), with 13.4% of isolates being nontypeable. The four isolates from throats most frequently identified were M1 (19.5%), M12 (15.3%), M3 (8.6%), and M28 (5%) with 19.4% of isolates being nontypeable. The sic gene of a subset of M1 strains (9.5% of the M1 collection) was sequenced. Of 36 sic types identified, the four most common were sic1.01 (22.8%), sic1.02 (14.9%), sic1.135 (10.5%), and sic1.178 (9.6%). Together these four sic types further characterized nearly 60% of the M1 strains sequenced. In summary, from the years 1993 to 1999, the NCS detected 54 M types, of which 10 different M types constituted 73.5% of the collection. M1 was the most common GAS M type circulating in the Canadian population, responsible for more than a quarter of the isolates typed. The most common throat isolates differed in M-type and proportion from those of invasive isolates. Sequencing the sic gene further characterized the most common M-type serotype 1 in a fashion that may be useful for epidemiologic investigations.
Tyrrell
Gregory J
GJ
The National Centre for Streptococcus, The Provincial Laboratory for Public Health for Alberta, The University of Alberta, Edmonton, Alberta T6G 2J2, Canada. g.tyrrell@provlab.ab.ca
Lovgren
Marguerite
M
Forwick
Betty
B
Hoe
Nancy P
NP
Musser
James M
JM
Talbot
James A
JA
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins / Q000145:classification*; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D002170:Canada / Q000453:epidemiology; D002352:Carrier Proteins / Q000145:classification*; D002648:Child; D002675:Child, Preschool; D014644:Genetic Variation; D006801:Humans; D008875:Middle Aged; D010447:Peptide Hydrolases; D017422:Sequence Analysis, DNA; D012703:Serotyping; D013290:Streptococcal Infections / Q000453:epidemiology / Q000382:microbiology; D013297:Streptococcus pyogenes / Q000145:classification* / Q000302:isolation & purification
D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; C097739:SIC protein, Streptococcus; C021908:opacity factor; C014689:streptococcal M protein; D010447:Peptide Hydrolases