Nosocomial transmission of Mycobacterium Tuberculosis in a regional hospital

Abstract

Nosocomial transmission of drug resistant tuberculosis is well-documented in South Africa. The level of risk varies by patient population and effectiveness of M.tb infection control measures. The risk is higher in places where large numbers of infectious M.tb patients are being treated, particularly in the absence of other infection control measures such as respiratory protection. Globalization has led to the exchange and circulation of the various strains worldwide, leading to greater global diversity of M.tb strains. This ultimately increased the risk of individuals being infected with more than one strain at a time ie; having mixed infection Methodology In this study, we investigated the extent of transmission of drug resistant M. tuberculosis between patients hospitalized in a specialized TB hospital. The study was carried out at the FOSA TB hospital, Durban, South Africa. Genotyping was performed using IS6110-RFLP and spoligotyping. Results A total of 52 patients were recruited, from which 28 isolates were successfully cultured and genotyped. Cluster analysis of the isolated genotypes suggests nosocomial transmission of drug resistant strains amongst the in-patients. A majority of the strains found among the patients belonged to the F15/LAM4/KZN family (64%), followed by three clusters of formerly uncharacterised strains which were named Unique I, II and III. Only one of the drug resistant isolates belonged to the Beijing family of strains. Several locations and activities were identified where transmission could potentially have occurred, but this could not be done for individual patients Conclusion Implementation of rapid diagnostic testing for drug-resistant TB and redesign of healthcare facilities, to minimize congregate spaces, are critical elements that should be included in TB infection control programs; in addition to administrative, environmental and personal protective measures.