Spoligotyping patterns and drug resistant of Mycobacterium tuberculosis in Sudan

Abstract

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Sudan has a high burden of tuberculosis with an estimated 93,000

new cases each year. The purpose of this study was to investigate the

genotypic patterns of

M. tuberculosis

strains circulating in Sudan and to

assess their susceptibly to anti-tuberculosis drugs. Isolates from 237 smear

positive tuberculosis patients were collected from different geographic

regions of the country. Spoligotyping was performed by the Kamerbeek

method and results were compared with the international SpolDB4 database

(Institut Pasteur, Guadeloupe).

Results revealed 28 clusters ranging in size from 12 to 57 isolates.

Seventy unique (unclustered) strains were observed, representing 30% of

the strains examined. The most frequently observed spoligotype patterns

belonged to the CAS family which represented 115 (48.5%) of isolates

studied. T1, H3, U and Beijing strains were found in 12 (5.1%), 11 (4.6%),

7 (3%) and 6 (2.5%) patients respectively. Strains belonging to the Beijing

family were found mainly in Western Sudan. Resistance to isoniazid,

rifampicin, ethambutol and streptomycin was observed in 18.1, 22.4, 22.2

and 32% of strains respectively. Twenty patients (8.4%) had MDR-TB of

which 10 were new cases. Seventeen patients with rifampicin resistant

tuberculosis were infected with CAS1-DELHI strains matching SIT 25 of

the SpolDB4 database and 3 were of the SIT 1 Beijing family. 15 loci

MIRU-VNTR typing subdivided the 17 CAS strains into one cluster of 5,

two clusters of 2 and 8 individual MIRU types. Similarly the 3 Beijing

spoligotypes were differentiated into a cluster of 2 and a single strain.

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The use of molecular strain typing provides a proactive approach that

may be used to initiate, and not just augment, traditional surveillance

outbreak investigation in Sudan. However, caution must be used when

interpreting clustered spoligotype patterns in this region