Researchers uncover lethal foreign TB strains in Kenya

Researchers have indicated that foreign strains of tuberculosis are now the most dominant in Western Kenya.

In a study conducted at Moi Teaching and Referral Hospital in Eldoret, researchers said the lethal Beijing strain is now the most common in the region.

The study sheds light on the genetic diversity of TB strains in the region, highlighting potential challenges for treatment and control efforts.

These strains relate to the Mycobacterium tuberculosis complex (MTBC), the commonest TB species in Kenya.

“Western Kenya has a number of Mycobacterium tuberculosis strains in circulation, with the Beijing strain being predominant,” they said in the study.

The study is titled: 'Genetic diversities of Mycobacterium tuberculosis complex species in Western Kenya.'

It is published in the latest issues of the Access Microbiology journal.

The researchers are Charles Komen, Paul Oyieng and Charles Ochieng from Maseno University and Henry Nyamogoba of Moi University.

TB remains a significant public health concern in Kenya, with drug-resistant strains posing a formidable challenge to treatment efforts.

Kenya on average reports more than 90,000 tuberculosis cases annually, the Ministry of Health’s national TB programme manager Dr Kathura Immaculate said last week.

There are at least 700 cases of drug-resistant TB in Kenya at any time.

Researchers in the current study said understanding the strains circulating is important in fighting drug resistance.

“Better ways of treating and controlling the spread of TB are imperative,” they said.

“This requires a better understanding of the MTBC species and strains circulating in a given region.”

In the present study, more than 12 strains of Mycobacterium strains, most of them foreign, were identified among the clinical isolates in circulation in Western Kenya.

The Beijing strain was the most dominant. This strain was first reported in Kenya in 2004 and is now predominant among patients in most Asian countries.

It has been associated with drug resistance and increased transmission.

Chelimo and his colleagues said the high prevalence of Beijing strain in Western Kenya could be related to increased interaction with East Asia.

This view is supported by a study in Tanzania in which the Beijing strain was high in the Serengeti ecosystem, a popular tourist destination.

Chelimo said the present study also revealed a considerable prevalence of unknown Mycobacterium strains.

The explanation for the existence and prevalence of unknown strains remains unclear.

One theory links it to epidemiological or evolutionary dynamics resulting in the formation of the unknown strains.

“An alternative explanation could be related to the high burden of HIV in Western Kenya,” the authors said.

“Thus resulting in a large number of immune-compromised persons, who facilitate the evolution of bacterial pathogens, including Mycobacterium species.”

The authors said it is important for clinicians and policymakers to know the types of TB and its strains for better management.

"By understanding the genetic diversity of MTBC strains, we can better tailor prevention, control and treatment strategies to address the specific challenges posed by different strains," they said.

Kenya has a five-year plan to combat tuberculosis in Kenya.

The plan, titled 'National Strategic Plan for Tuberculosis, Leprosy and Lung Health', was unveiled in January by Public Health PS Mary Muthoni.

The PS said the ministry is committed to further reducing the cases of TB reported in a year.

"In 2022, Kenya reported 90,560 drug-sensitive TB cases, an increase compared to the 77,854 cases reported in 2021," she said.

The PS cautioned medical professionals against cases of misdiagnosis, which have led to deaths in some cases where patients suffered from tuberculosis.

Muriuki said the ministry is working with the CDC, WHO and USAid to achieve a TB-free Kenya.

She said the plan will be an inclusive guide that will be used in the fight to end TB in Kenya.