Patterns and profiles of drug resistance-conferring mutations in Mycobacterium tuberculosis genotypes isolated from tuberculosis-suspected attendees of spiritual holy water sites in Northwest Ethiopia

Abstract

PurposeThis study examined the patterns and frequency of genetic changes responsible for resistance to first-line (rifampicin and isoniazid), fluoroquinolones, and second-line injectable drugs in drug-resistant Mycobacterium tuberculosis (MTB) isolated from culture-positive pulmonary tuberculosis (PTB) symptomatic attendees of spiritual holy water sites (HWSs) in the Amhara region.Patients and methodsFrom June 2019 to March 2020, a cross-sectional study was carried out. A total of 122 culture-positive MTB isolates from PTB-suspected attendees of HWSs in the Amhara region were evaluated for their drug resistance profiles, and characterized gene mutations conferring resistance to rifampicin (RIF), isoniazid (INH), fluoroquinolones (FLQs), and second-line injectable drugs (SLIDs) using GenoType®MTBDRplus VER2.0 and GenoType®MTBDRsl VER2.0. Drug-resistant MTB isolates were Spoligotyped following the manufacturer’s protocol.ResultsGenetic changes (mutations) responsible for resistance to RIF, INH, and FLQs were identified in 15/122 (12.3%), 20/122 (16.4%), and 5/20 (25%) of MTB isolates, respectively. In RIF-resistant, rpoB/Ser531Lue (n = 12, 80%) was most frequent followed by His526Tyr (6.7%). Amongst INH-resistant isolates, katG/Ser315Thr1 (n = 19, 95%) was the most frequent. Of 15 MDR-TB, the majority (n = 12, 80%) isolates had mutations at both rpoB/Ser531Leu and katG/Ser315Thr1. All 20 INH and/or RIF-resistant isolates were tested with the MTBDRsl VER 2.0, yielding 5 FLQs-resistant isolates with gene mutations at rpoB/Ser531Lue, katG/Ser315Thr1, and gyrA/Asp94Ala genes. Of 20 Spoligotyped drug-resistant MTB isolates, the majority (n = 11, 55%) and 6 (30%) were SIT149/T3-ETH and SIT21/CAS1-Kili sublineages, respectively; and they were any INH-resistant (mono-hetero/multi-). Of 15 RIF-resistant (RR/MDR-TB) isolates, 7 were SIT149/T3-ETH, while 6 were SIT21/CAS1-Kili sublineages. FLQ resistance was detected in four SIT21/CAS1-Kili lineages.ConclusionIn the current study, the most common gene mutations responsible for resistance to INH, RIF, and FLQs were identified. SIT149/T3-ETH and SIT21/CAS1-Kili constitute the majority of drug-resistant TB (DR-TB) isolates. To further understand the complete spectrum of genetic changes/mutations and related genotypes, a sequencing technology is warranted.

Spiritual Holy Water Sites in Ethiopia: Unrecognized High-Risk Settings for Transmission of Pulmonary Tuberculosis

“…In our study, participants who shared living space at HWSs were tenfold more likely to have culture-positive PTB. This is because rooms at the HWSs are built as temporary waiting spaces, and they are very small, overcrowded, and poorly ventilated, which can intensify the risk of TB transmission [ 13 , 18 , 52 ]. The overcrowded and poorly ventilated waiting rooms at the HWS, prolonged stays at the HWS, and poor healthcare-seeking behaviors of individuals worsen the active transmission of TB at the HWS.…”

“…Our findings were comparable to those of prior studies [ 32 , 34 , 35 ]. Congregate settings, such as HWSs, are places where people live together, and it is common for people to share living space [ 13 , 18 , 52 ]. Hence, poor living conditions and overcrowding in the shared room can increase TB transmission.…”

“…In the current study, the prevalence of any DR-TB (resistance to RIF and/or INH) was 16.4%, indicating that it is a significant concern among HWS attendees. This is likely because many people with TB (infected with DR-TB strains) attended HWSs, resulting in DR-TB transmission [ 13 , 18 , 52 ]. This is comparable with previous reports from the study region (10.3 to 20.2%) [ 53 – 59 ], and other parts of Ethiopia (11.1 to 18.4%) [ 60 – 65 ].…”

“…Interestingly, all five FLQs-resistant and/or pre-XDR-TB isolates were identified at the South Wello zone. This suggests that these pre-XDR-TB strains may be circulating in this study site and have recently disseminated, although a molecular epidemiology analysis with strong discriminatory power would be required to confirm genotypic similarities, and recent transmission [ 18 , 52 ]. Consistent with our result, an earlier study conducted in the same study region found that 5.7% of TB patients had pre-XDR-TB strains [ 7 ].…”

“…Interestingly, five FLQs-resistant and/or pre-XDR-TB strains were identified at the South Wello zone study site. This could be because DR-TB is prominent in this study area and there is recent TB transmission, although further molecular epidemiology analysis with strong discriminatory power would be required to confirm genotypic similarities and transmission patterns of the resistant strains [ 18 , 52 ].…”