Unexpectedly High Proportion of Ancestral Manu Genotype Mycobacterium tuberculosis Strains Cultured from Tuberculosis Patients in Egypt

Abstract

Tuberculosis is one of the important public health problems in Egypt. However, limited information on the Mycobacterium tuberculosis genotypes circulating in Egypt is available. A total of 151 M. tuberculosis strains were characterized by spoligotyping. The results revealed that 74.8% of M. tuberculosis isolates grouped into 13 different clusters, while 25.2% had unique spoligotype patterns. Comparison with an international spoligotyping database (the SITVIT2 database) showed that types SIT53 (T1 variant) and SIT54 (Manu2 variant) were the most common types between cluster groups. In addition, new shared types SIT2977, SIT2978, and SIT2979 were observed. The results identified for the first time an unusually high proportion of ancestral Manu strains of M. tuberculosis from patients in Egypt. The percentage of the Manu clade in this study (27.15%) was significantly higher than its overall representation of 0.4% in the SITVIT2 database. We show that in Egypt tuberculosis is caused by a predominant M. tuberculosis genotype belonging to the ancestral Manu lineage which could be a missing link in the split between ancestral and modern tubercle bacilli during the evolution of M. tuberculosis.Despite the availability of antituberculosis (anti-TB) drugs, the disease burden of human TB remains a very serious and widespread public health problem. Many of the 22 countries most affected by human TB identified by the World Health Organization (WHO) are developing countries (11). Although Egypt is not on the WHO list of 22 high-TB-burden countries, it is considered one of the high-burden countries in WHO's Eastern Mediterranean region, where TB constitutes the second most important public health problem after schistosomiasis (21). Every year, the National Tuberculosis Control Program of the Ministry of Health and Population (MOHP) registers over 12,000 new TB patients; more than 50% of the cases are sputum smear-positive pulmonary TB. On the basis of an annual risk of infection of 0.32%, it is estimated that about 8,000 people receive a diagnosis of TB at facilities other than those of MOHP (25).In the context described above, it is important to have a precise picture of the predominant and emerging Mycobacterium tuberculosis clones in Egypt, in order to have a first snapshot of the epidemiology of TB. The advent of molecular typing methods has given a new boost to epidemiological studies of TB in recent years (3); the most commonly used methods are IS6110-based restriction fragment length polymorphism (RFLP) (IS6110-RFLP) and spoligotyping (12,22). As opposed to IS6110-RFLP, which was considered the "gold standard" for the genotyping of M. tuberculosis in the early 1990s (22) and which is time-consuming and labor-intensive and requires large amounts of highly purified DNA, PCR-based spoligotyping avoids the problems associated with the slow growth of these bacteria, thereby offering the possibility of the rapid recognition of outbreaks (2,4,12). The clinical usefulness of spoligotyping is determined by its rapidity both in d...

Spoligotype Profile of Mycobacterium tuberculosis Complex Strains from HIV-Positive and -Negative Patients in Nigeria: a Comparative Analysis

“…Soon afterwards, it was tentatively subdivided into the Manu1 (deletion of spacer 34), Manu2 (deletion of spacers 33 and 34), and Manu3 (deletion of spacers 34 to 36) sublineages, and it was suggested that it could represent an ancestral clone of principal genetic group (PGG) 1 strains (4). Manu lineage strains were reported from Saudi Arabia (2) and Tunisia (17) and more recently in a study from Egypt, where it represented as much as 27% of all isolates (15). However, according to a recent report, a fraction of Manu2 patterns could also arise due to mixed infection by a strain belonging to evolutionarily recent H, LAM, X, and T lineages with a Beijing strain, a risk that may be excluded by looking for genomic deletion of region of difference RD105, which is characteristic of the Beijing lineage (26).…”

Comparison of spoligotyping, mycobacterial interspersed repetitive units typing and IS6110-RFLP in a study of genotypic diversity of Mycobacterium tuberculosis in Delhi, North India

“…Using this approach, one considers that all intermediate stages are present within the sample analysed by including first the individual that shows the greatest number of possible linkages to other individuals in the population studied. We used this method to highlight the phylogenetic links between two spoligotypes differing by changes observed in direct variable repeats (Helal et al 2009). Consequently, the lengths of the branches in the tree indicate the level of change induced by the loss or gain of spoligotype spacers in the 43-oligonucleotide format that induce a shift from one allele to another; the solid lines represent a single spacer change, dotted lines represent two spacer changes (black) or more than two spacer changes (gray).…”

“…Phylogenetic analysis -The evolutionary relationships among all of the observed spoligotypes were studied by drawing a minimum spanning tree (MST) with BioNumerics software as reported previously (Helal et al 2009). MST is an undirected network in which all of the samples are linked together with the fewest possible linkages between nearest neighbours.…”

Tuberculosis Problem In Dakahlia Governorate, Egypt

“…24 Although Egypt is not on the WHO list of 22 high-TB-burden countries, it is considered one of the high-burden countries in WHO's Eastern Mediterranean region. 23 Tubercular decay has been found in the spines of Egyptian mummies from 3000-2400 BC. 25 The fi rst evidence that human tuberculosis was present in ancient Egypt came from typical macroscopic osseous changes in human remains, which were in this instance the well preserved Egyptian mummies.…”

“…Tuberculosis is one of the important public health problems 23 . It constitutes a major public health problem after HCV and bilharziasis.…”