Group A Streptococcus Outbreak in a Canadian Armed Forces Training Facility

Abstract

Between December 2016 and April 2017, two cases of invasive Group A Streptococcus (GAS) infections were reported at a Canadian military training facility. An outbreak was declared and a field investigation was launched to characterize the outbreak and identify associated risk factors to limit transmission. Throat culture data from military personnel at the garrison were analyzed. Investigators tracked invasive GAS cases and non-invasive hospitalized GAS cases, and conducted site visits and case interviews. Sensitivity and specificity for a rapid antigen detection test were evaluated. Molecular typing and phylogenomic relationships of outbreak isolates were analyzed using whole-genome sequencing. During this outbreak, four invasive cases were reported and six non-invasive cases were hospitalized. In a sample of 705 throat cultures examined, 35.2% were GAS-positive. Among 65 platoon contacts of one invasive case, 30.2% were GAS-positive. Reluctance to seek medical care, challenges in following cough etiquette, and low compliance with antibiotics were identified among recruits. The rapid antigen detection test had low sensitivity (31.6%) during the outbreak. The outbreak sequence type was emm6.4 and outbreak isolates were highly related phylogenetically, differing by 0-4 single nucleotide variants. This is the first report of a GAS outbreak among Canadian military trainees. Increased surveillance of GAS infections, increased control measures and outbreak-specific clinical guidelines were implemented in-garrison. No further invasive GAS cases were identified. A GAS surveillance system was implemented and efforts to improve antibiotic compliance and medical consultation were recommended.

A Review of Streptococcus pyogenes: Public Health Risk Factors, Prevention and Control

“…A comparable study conducted in Canada also reported similar findings [62]. Hammond-Collins et al [49] also conducted a study on GAS-infected cases between August 2016 to January 2018 in Belgium. The results showed incidence rates of 2333/100,000 persons in homeless groups and 25/100,000 persons in non-homeless groups, showing a higher incidence (100 times higher) for homeless persons compared to non-homeless persons.…”

“…The common environments for GAS infections included schools, nurseries and kindergartens [16,36,37], hospitals [33,34,[38][39][40][41], homeless shelters [22,50], care homes [38,[42][43][44][45][46][47][48] and military training facilities [49].…”

“…GAS infections are commonly spread in schools, nurseries and kindergartens, hospitals, care homes, military camps and homeless shelters [8,22,33,34,[36][37][38][39][40][41][42][43][44][45][46][47][48][49][50]. A review of epidemiological data for scarlet fever for the period 2005-2015 conducted by Zhang et al [8] in Hong Kong showed that the infections were higher during the months when schools were open.…”

“…Moreover, sharing bedding and personal items like towels is also a predisposing factor for the transmission of GAS infections [121]. High numbers of social contacts, a key environmental factor, which is common in schools, hospitals and other enclosed social places, increase the chances of the transmission of GAS infections [49,137] Personal hygiene and hand hygiene are key to the control and prevention of communicable diseases like common cold, diphtheria, rubella and GAS infections [33,48]. Poor personal and hand hygiene have been proven to be risk factors for GAS infections in all age groups [15,42].…”

Phylogenetic analysis of streptococci in samples taken from the throat cultures of children in Turkey and the presence of mef(A), mef(E), erm(B) and erm(TR) genes in patients withStreptococcus pyogenes

“…Both acute and chronic forms of GAS can be seen at the age of three and over; therefore, they are diseases that frequently occur in a wide age group. [14] Contagion occurs with close contact through infected droplets. In addition to domestic transmission, other environments with a high risk of transmission include public areas, such as schools, barracks, and kindergartens.…”