Potentially transmissible TB in undiagnosed cases | Top Vip News

Tuberculosis (TB) is one of the oldest infectious diseases known to man and one of the “big three” [along with malaria and HIV/AIDS]. It is predicted to infect approximately a quarter of the world’s population and has resisted elimination despite focused research and development of antibiotics.

A recent publication by Patterson and colleagues at Weill Cornell Medical College in the United States may address this ongoing reservoir of infection. Using bioaerosol sample collection, the authors detected tuberculosis complex bacteria in patients presenting with symptoms. The bacteria were present regardless of these patients’ tuberculosis diagnosis and their presence was not affected by antibiotic treatment. These findings have strong implications for the sustained transmission of tuberculosis and the global burden of disease.

The study was carried out in Cape Town, South Africa, where tuberculosis is endemic. The 102 presumed cases presented one or more symptoms of the disease (weight loss, night sweats, persistent cough and loss of appetite). The cases were analyzed using X-pert Ultra, a rapid test recommended by the WHO for the initial detection of tuberculosis. They were then separated into three categories: rapid test positive, rapid test negative but clinically positive (usually by chest x-ray), and rapid test negative and clinically negative (labeled “undiagnosed”). The researchers collected bioaerosol samples, containing everything breathed or coughed, at 0 days, 2 weeks, 2 months, and 6 months from diagnosis. All diagnosed cases (groups A and B) received antibiotic treatment for 6 months.

The resolution of tuberculosis cases may depend on time but not on medications

M tuberculosis complex (MTBC) bacteria were detected in all three groups on day 0, and both the proportion of cases breathing MTBC and the number of bacteria were comparable between the groups. Over 6 months, both bacterial load and clinical symptoms in study participants decreased. However, this was similar in all three groups: antibiotic treatment did not affect bacterial load or symptoms. This implies that the resolution of tuberculosis cases depends on time but not on medications. Furthermore, the transmission of tuberculosis is potentially independent of the severity of symptoms, so subclinical or undiagnosed cases may be spreading the infection undetected.

In response to this finding, the researchers confirmed that the bacteria in the bioaerosol samples were MTBC using DNA sequencing and microscopy. They found that the bacteria were metabolically active (alive), but lacked their characteristic acid-fast staining. This had previously been observed in infectious MTBC as early as 1883. Researchers successfully cultured very few samples, but MTBC is notoriously difficult to culture from clinical samples. Whether the bacteria collected in this study are capable of becoming infected remains to be determined, and this will likely be the subject of further study.

GlobalData epidemiologists predict approximately 3.7 million diagnosed incident cases of tuberculosis by the end of 2024 in the 16MM [mature markets]: Australia, Brazil, China, France, Germany, India, Italy, Japan, Mexico, Russia, South Africa, South Korea, Spain, UK and US) by the end of 2024. The results of this bioaerosol study suggest The transmission of tuberculosis that produces this high number of cases may be due to the transmission of undiagnosed and unmedicated cases along with active infections. If this is confirmed, new case definitions and infection control methods may be needed to curb the spread of tuberculosis in the future.