An investigation of the first case of extensively drug-resistant tuberculosis, Phang nga Province, Thailand, 2018

Abstract

Background: On 29th May 2018, the Phang Nga Provincial Public Health Office (PPHO) was notified of the extensively drug-resistant tuberculosis (XDR-TB) confirmed case in Takuapa district, Phang nga province from the Office of Disease Prevention and Control Region 11 (ODPC11) Nakhon Si Thammarat. The XDR-TB case investigation was conducted by the Provincial Surveillance Rapid Response Team (SRRT) of the Phang Nga PPHO, in collaboration with the Bureau of Epidemiology and the ODPC11 in order to 1) confirm the diagnosis, 2) examine the clinical manifestations, 3) determine the mode of transmission, risk factors and the extent of outbreak, and 4) implement control measures complying with Communicable Disease Control Act B.E. 2558.
Methods: The descriptive epidemiology was applied. The following case investigations such as clinical manifestations of the XDR-TB case, the mode of transmission, risk factors and the extent of outbreak were examined using medical record review and case interviewing. The contact cases were explored using chest x-ray and the diagnosis of the XDR-TB case was confirmed using sputum Acid Fast Bacilli (AFB) stain and GeneXpert MTB/RIF assay while in child using Tuberculin skin test and blood interferon gamma release assay (IGRA).
Results: The 41-year-old Thai male TB case was a carpenter who was working for the hotel with history of alcoholic drinking and smoking. In 2017, he was registered as new pulmonary tuberculosis and cure treatment with category 1 regimen. In 2018, he was registered as relapsed pulmonary tuberculosis. Then he developed XDR-TB confirmed by AFB/GeneXpert MTB/RIF. By active case findings, there were 2 household contact cases and 26 workplace contact cases; all of them showed normal lung condition by chest x-ray and no TB infection by AFB/GeneXpert MTB/RIF and Line Probe Assay. Four contact persons with having work exposure and abnormalities on chest radiographs were found to be negative by GeneXpert while only 1 person was positive by IGRA. Additionally, these findings were not epidemiologically linked with both 3 MDR-TB cases and one Pre XDR-TB case whose medical records were retrieved.
Conclusions: The first case of XDR-TB in Phang Nga province posed the risk of XDR-TB infection due likely to risk factors that included the history of previous TB treatment failure, lack of drug compliance by directly observed treatment by any healthcare workers, inappropriate storage of drugs that caused their decompositions, and history of alcohol drinking and smoking. Consequently, the vulnerability might cause mixed infections with both DS-TB and XDR-TB at the early TB onset in 2017, and perhaps reinfection with XDR-TB between during radical treatment with DS-TB and during the XDR-TB onset in March 2017. The infection control personnel ordered the issuing of the isolation that treated this XDR-TB case and might interrupt the spread of XDR-TB.