title: emm typing of M nontypeable invasive group A streptococcal isolates in Israel.
abstract: We performed emm typing of M nontypeable invasive group A streptococcal (GAS) isolates collected in a prospective population-based study in Israel. One hundred twenty of 131 isolates (92%) had emm sequences compatible with GAS, consisting of 51 different emm types. Eleven isolates were found to be group G streptococcus. Of the 120 isolates, 55 (46%) belonged to 32 types for which there were no typing sera available in the Streptococcal Reference Laboratory in Israel. The other 65 (64%) isolates, consisting of 19 types, had sera available and therefore could have been serotyped. Forty-three isolates had T and emm types which were not correlated according to standard M-typing protocols and were therefore missed. The principal effect of emm typing was the addition of 32 types not previously identified in Israel and the discovery of new associations between emm and T types. emm typing did not significantly change the proportion of M types; the five most common types were 3, 28, 2, 62, and 41. Twenty different types comprised 80% of all isolates. No new emm sequences were discovered. emm typing emphasized the unusually low incidence of M1 strains causing severe disease in Israel. As serological typing of GAS becomes more problematic due to lack of sera and the appearance of new emm types, reference laboratories should replace M typing with emm sequence typing. Development of a GAS vaccine relies on the emm type distributions in different geographical locations. In our study, 7% of isolates (types 41 and 62) are not included in a 26-valent vaccine that is being studied.
authors.affiliation: Department of Clinical Microbiology and Infectious Diseases, Hadassah University Medical Center, Jerusalem, Israel. MOSESA@MD2.HUJI.AC.IL
authors.forename: Allon E
authors.initials: AE
authors.lastname: Moses
authors.forename: Carlos
authors.initials: C
authors.lastname: Hidalgo-Grass
authors.forename: Mary
authors.initials: M
authors.lastname: Dan-Goor
authors.forename: Joseph
authors.initials: J
authors.lastname: Jaffe
authors.forename: Ilanit
authors.initials: I
authors.lastname: Shetzigovsky
authors.forename: Miriam
authors.initials: M
authors.lastname: Ravins
authors.forename: Zinaida
authors.initials: Z
authors.lastname: Korenman
authors.forename: Ronit
authors.initials: R
authors.lastname: Cohen-Poradosu
authors.forename: Ran
authors.initials: R
authors.lastname: Nir-Paz
mesh_terms: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D015373:Bacterial Typing Techniques; D002352:Carrier Proteins / Q000235:genetics*; D006801:Humans; D007557:Israel / Q000453:epidemiology; D011446:Prospective Studies; D017422:Sequence Analysis, DNA; D012703:Serotyping; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D013297:Streptococcus pyogenes / Q000145:classification* / Q000235:genetics
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; C014689:streptococcal M protein