Molecular characterisation of group A streptococcus isolates recovered from the north-west of Pretoria, South Africa

Background. Group A streptococcus (GAS) is a human pathogen responsible for a wide range of invasive and non-invasive infections. Pharyngitis caused by GAS may have complications such as acute rheumatic fever subsequently leading to rheumatic heart disease (RHD). RHD continues to have high morbidity and mortality and affects millions of children and young adults, mostly in developing countries. An effective preventive vaccine against GAS may reduce the morbidity and mortality. A 30-valent M-protein-based vaccine is currently at the clinical trials stage of development. Potential vaccine coverage will depend on the geographical distribution of GAS emm (M protein) types.Objectives. To determine the emm types of GAS isolates circulating in the north-west of Pretoria, South Africa.Methods. Throat swabs were collected from patients aged 3 - 20 years presenting with pharyngitis at one local clinic. In addition, GAS clinical isolates were collected from the National Health Laboratory Service diagnostic laboratory. Emm genotyping was done on the GAS isolates by amplification of the emm gene followed by sequencing of the 5′ portion of the gene. The emm types were correlated with the types in the vaccine.Results. A total of 54 GAS isolates were collected, comprising 19 pharyngitis and 35 clinical isolates. We found 15 different emm types among the 43 GAS isolates that were successfully sequenced. Eleven isolates (20%) could not be typed. The most prevalent emm type was 92 (26%), which is part of the 30-valent vaccine. This was followed by emm 25 and 75, each accounting for 12% of the isolates. Up to 67% of the emm types are not covered in the 30-valent vaccine.Conclusions. Fifteen emm types were identified, of which 92 was the most prevalent. It is concerning that 67% of the emm types are not covered in the vaccine currently under development. It is recommended that surveillance studies be extended to include other parts of the country in order to expand knowledge of the circulating emm types

Efficacy assessment of ultraviolet germicidal irradiation (UVGI) devices for inactivating airborne Mycobacterium tuberculosis

INTRODUCTION : Airborne transmission of Mycobacterium tuberculosis (TB) and other infectious agents within indoor environments has been a recognised hazard for decades. The increasing incidence of airborne diseases and drug resistance has renewed interest in ultraviolet germicidal irradiation (UVGI) to reduce transmission. The aim of this study was to determine the efficacy of UVGI devices, available in South Africa, for inactivating airborne TB bacteria. METHODOLOGY : Thirteen UVGI devices from major South African suppliers were challenged with M. tuberculosis H37Ra bacilli (~1 x 106 vegetative cells/ml) when OFF and when ON, for one hour. Air samples (n = 130) were collected using PTFE filters. Sample extracts were analysed using quantitative real time polymerase chain reaction (qPCR), targeting the 16 subunit ribosomal ribonucleic acid (16S rRNA) gene. The DNA extraction efficiency was also determined, using the Quanti-iT PicoGreen assay. Irradiance measurements, including ultraviolet-C (UVC) output and maintained UVC flux of the devices, were recorded using an integrating sphere. The data were analysed using descriptive and inferential statistics. RESULTS : There was no difference between the mean concentration of the DNA extracted from the aqueous and air samples (p = 0.3494). An accumulation of TB DNA copies/m3 with increasing time, when the devices were OFF, was observed as expected. Forty-six percent (6 of 13) of UVGI devices tested yielded 100% effectiveness in a controlled laboratory setting; 5 of 6 had built-in fans which may have contributed to their efficacy. The effectiveness of the remaining devices ranged from 43.7% to 95.1%. CONCLUSION : The efficacy of UVGI devices available in South Africa is highly variable, with minimum UVC output. The reduced levels of effectiveness of some devices might be due to the design of the devices, which needs to be reassessed by manufacturers. The effectiveness of UVGI devices and quantification of microbial survival rate can be assessed robustly using qPCR.The NHLS trust fund and the Presidents Emergency Plan for Aids Relief (PEPFAR) grant, together with the US-CDC grant (1U2GPS002710): CoAA to the CSIR to assist the South African National Department of Health and Provincial Departments of Health integrate TB/HIV Counselling and Testing, and Care and Treatment in the Republic of South Africa.http://www.occhealth.co.zaam2018Electrical, Electronic and Computer Engineerin

Pilot study to detect airborne Mycobacterium tuberculosis exposure in a South African public healthcare facility outpatient clinic

BACKGROUND : Airborne transmission of Mycobacterium tuberculosis (TB) remains an occupational health hazard particularly in crowded and resource limited healthcare settings. AIM : The study aimed to quantify airborne TB in a busy outpatient clinic in Gauteng, South Africa. METHODS : Personal (HCWs) and stationary air samples were collected in the Polyclinic and Administrative block. Quantitative real-time PCR was used to detect airborne TB. Walkthrough observations and work practices of HCWs were also recorded. FINDINGS : TB was detected in 11/49 (22.4%) of the 9/25 (36%) personal and 2/24 (8.3%) stationary samples. Samples from 5 of 10 doctors (50%) and 3 of 13 nurses (23%) were positive. Repeat measurements on different days showed variable results. Most of the HCWs (87.5%) with positive results had been in contact with coughing patients and had not worr respiratory masks despite been training. CONCLUSION : The use of air sampling coupled with real-time qPCR is a simple and effective tool to demonstrate the risk of TB exposure. The findings provide an impetus for hospital management to strengthen TB infection prevention and control measures.Canadian Institutes of Health Research (CIHR).http://www.elsevierhealth.com/journals/jhinhb2016School of Health Systems and Public Health (SHSPH