The Beijing genotype of Mycobacterium tuberculosis was
identified as a high-frequency strain among multidrug-resistant tuberculosis
isolates, according to a study.
From a sample of 324 M. tuberculosis isolates retrieved from the
Centro Internacional de Entrenamiento e Investigaciones Médicas in Cali,
Colombia, 160 were thawed and cultured on Lowenstein-Jensen agar slants.
Of these, a Beijing family strain (SIT 190) caused the largest cluster
among MDR isolates (n=24) and was found in two of four extensively
drug-resistant tuberculosis (XDR TB) isolates. The two isolates were found in
female patients aged 16 and 24 years, and the Beijing genotype was found to
have a strong correlation with female patients, as well as patients living in
“In Buenaventura, where a high rate of primary drug resistance has
been observed, the Beijing genotype is associated with MDR TB and thus
transmission,” the researchers wrote. “Moreover, given the limited
number of MDR isolates tested, the emergence of Beijing strains in Colombia may
already be much larger than what we observed.”
The high frequency of the Beijing strain may be caused by bacteriologic
factors, host factors, or both, and has become a public health problem in
Buenaventura, Colombia, they said.