Date of Award

11-2016

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Dr. Abdulmajeed Alkhajeh

Second Advisor

Dr. Khaled Abbas El Tarabily

Third Advisor

Dr. Nihar Ranjan Dash

Abstract

Streptococcus pyogenes, also known as Group a streptococcus (GAS), causes a wide variety of diseases in children and adults, and it frequently infects the pharynx and skin; pharyngitis and tonsillitis are one of the commonest diseases caused by this pathogen. GAS evaded by many virulence factors, however, the most significant part is the M protein, which plays a major role in its pathogenicity. Over 225 M protein types have been identified so far by the emm typing technique. Identification and emm typing of GAS is an essential part of epidemiological and pathogenic studies of streptococcal diseases, as different regions of the world have different common emm types. This diversity and the different distribution of the emm types among regions cause an obstacle in developing an effective vaccine. Currently, there are many studies on a 26 polyvalent vaccine targets a certain common emm types in the high- income countries, such as the USA, Canada, and Europe while this vaccine has low coverage in the low-income countries and the pacific. As there are not enough information about the distribution of GAS and diversity of the emm types in the UAE and the region, it would be difficult to evaluate the efficacy and the coverage of the proposed 26 polyvalent vaccine for the UAE and the region. The main objective of this thesis is to establish the carriage rate of Group A Streptococcal throat colonization among healthy school children in Al Ain, to identify the common emm types from the positive GAS isolates and to compare our findings with the most common emm types used to develop the 26-polyvalent vaccine. 500 throat swabs samples were collected from 500 schoolchildren aged from 5-10 years old (250 male students and 250 Female students) from primary schools from Al Ain city in the UAE. The samples were collected during the month of October 2015 and

November 2015, and cultured on blood agar using the standard microbiological techniques for GAS identification. Only10% (50/500) of the schoolchildren carried GAS in their throats, 50 GAS isolates were analyzed, and emm typed using the sequence emm typing technique. A total of 7 different emm types were detected from the 50 GAS isolates, where emm3 was the most common which accounted for 24 (48%) followed by emm12 and emm1, which represented 10 (20%) and 4 (8%) respectively. These findings indicate that the 26-poly vaccine, which considered a poor coverage in contrast to the 90% coverage in the western region, covers only 23% of emm types from Al Ain

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