Emm types of invasive group A streptococcal isolates from Thai patients at King Chulalongkorn Memorial Hospital from 1995-1999.

Emm (M protein gene) typing was used to analyze group A streptococcal (GAS) clinical isolates in Thailand from in-patients at Chulalongkorn University Hospital (CUH) between January 1, 1995 and December 31, 1999. Forty GAS isolates were recovered from blood and other sterile sites from 40 patients presenting with different types of infections. A variety of emm sequences (24 types) have been reported in this study including the identification of 2 novel emm variants demonstrating the diverse population of invasive GAS isolates in Thailand. The common emm types include emm1 (5 isolates, 12.5%), emm22 (4 isolates, 10%), emm25 (3 isolates, 7.5%), emm61 (3 isolates, 7.5%), and STNS1033 (3 isolates, 7.5%). No particular emm types of GAS tend to be frequently associated with specific clinical presentation, complication, or anatomic site of infection. This report provides epidemiological information from Thailand where streptococcal infections and their sequelae are important public health problems. In addition, the results are useful for the development of a suitable M protein based vaccine in the future.

Outbreak of uncommon type of group A streptococcal pharyngitis among cadets at the Chulachomklao Royal Military Academy, Nakhon Nayok, Thailand.

A large outbreak of group A Streptococcus (GAS) pharyngitis occurred among 285 cadets at the Chulachomklao Royal Military Academy, Nakhon Nayok between September 22 and 27, 1996. An epidemiologic investigation was conducted to determine the source of infection. It seemed that respiratory droplets were the mechanism of spread, although foodborne transmission could not be excluded. To assess the presence of the outbreak strain in the community, conventional serotyping and molecular typing by emm sequencing were performed. The results demonstrated the advantage of molecular typing compared to serotyping and suggested that the outbreak was caused by the same strain. Interestingly, the involvement of the causative emm79 strain, which is an uncommon type of GAS disease, in a large number of patients may imply the invasive potential of this organism.