Abstract:

Objective To understand the drug resistance situation, genotype composition and the correlation between genotype and drug-resistant of multidrug-resistant Mycobacterium tuberculosis (MDR-MTB) in Guangxi Zhuang Autonomous Region (referred to as Guangxi), thereby providing a theoretical basis for the prevention and control of MDR-MTB. Methods Using continuous monitoring methods, 5 cities including Guigang, Baise, Chongzuo, Guilin, and Fangchenggang on East, West, South, North, and Central of Guangxi were selected as monitoring points, and random number table method was used to extract 21 counties (cities, districts) from 5 cities. A total of 1514 culture-positive MTB strains which registered and treated in the local tuberculosis prevention and treatment institution were collected from 2016 to 2017. The drug susceptibility test to isoniazid (INH), rifampin (RFP), ethambutol (EMB), streptomycin (Sm), Ofloxacin (Ofx) and kanamycin (Km) was performed using the ratio method recommended by WHO. Finally, 51 strains were identified as MDR-MTB strains. Genotyping was performed by melting curve analysis-based spoligotyping (McSpoligotyping), and then the results were compared with the SpolDB 4.0 database. Results The drug resistance rates to EMB, Sm, Ofx and Km of 51 MDR-MTB strains were 41.18% (21/51), 31.37% (16/51), 9.80% (5/51) and 1.96% (1/51), respectively. Beijing genotype strains accounted for 56.86% (29/51) and non-Beijing genotype strains accounted for 43.14% (22/51). Among the strains resistant to EMB, there were 14 Beijing genotype strains, accounting for 66.67% (14/21) and 7 non-Beijing genotype strains, accounting for 33.33% (7/21), the difference was not statistically significant (χ ²=1.399, P=0.237). Among the strains resistant to Sm, there were 11 Beijing genotype strains, accounting for 68.75% (11/16) and 5 non-Beijing genotype strains, accounting for 31.25% (5/16), the difference was not statistically significant (χ ²=1.343, P=0.246). Among the strains resistant to Ofx, there were 9 Beijing genotype strains, accounting for 60.00% (9/15) and 6 non-Beijing genotype strains, accounting for 40.00%(6/15), the difference was not statistically significant (χ ²=0.085, P=0.770). Among the strains resistant to Km, there was 1 Beijing genotype strain, accounting for 100.00% (1/1), and no non-Beijing genotype strain, accounting for 0.00% (0/1), the difference was not statistically significant (P=1.000). Conclusion We should pay attention to the resistance of MDR-MTB strains to EMB, Sm, Ofx and Km in Guangxi. MDR-MTB strains are mainly Beijing genotype. There are no significant differences in the resistance rates of Beijing and non-Beijing genotypes to EMB, Sm, Ofx and Km.

Key words: Tuberculosis, multidrug-resistant, Gene, Oligonucleotide array sequence analysis, Data interpretation, statistical, Small-area analysis