scholarly journals Alterations in the Spectrum of Spontaneous Rifampicin-Resistance Mutations in the Bacillus subtilis rpoB Gene after Cultivation in the Human Spaceflight Environment

2018 ◽  
Vol 9 ◽  
Author(s):  
Patricia Fajardo-Cavazos ◽  
Joshua D. Leehan ◽  
Wayne L. Nicholson
Keyword(s):  
Bacillus Subtilis ◽  
Rpob Gene ◽  
Rifampicin Resistance ◽  
Resistance Mutations ◽  
Human Spaceflight

The Spectrum of Spontaneous Rifampicin-Resistance Mutations in the Bacillus subtilis rpoB Gene Depends on the Growth Environment

2021 ◽  
Author(s):  
Joss D. Leehan ◽  
Wayne L. Nicholson
Keyword(s):  
Bacillus Subtilis ◽  
Growth Condition ◽  
Sole Carbon Source ◽  
Minimal Medium ◽  
Target Gene ◽  
Rpob Gene ◽  
Relative Fitness ◽  
Rifampicin Resistance ◽  
Resistance Mutations ◽  
Growth Environment

Results from previous investigations into spontaneous rifampicin-resistance (Rif R ) mutations in the Bacillus subtilis rpoB gene suggested that the spectrum of mutations may depend on the growth environment. However, these studies were limited by low sample numbers, allowing for the potential distortion of the data by the presence of ‘jackpot’ mutations which may have arisen early in the growth of a population. Here we addressed this issue by performing fluctuation analyses to assess both the rate and spectrum of Rif R mutations in two distinct media: LB, a complete laboratory medium and SMM Asn , a minimal medium utilizing L-asparagine as the sole carbon source. We cultivated 60 separate populations under each growth condition and determined that the mutation rate to Rif R to be slightly but significantly higher in LB cultures. We then sequenced the relevant regions of rpoB to map the spectrum of Rif R mutations under each growth condition. We found a distinct spectrum of mutations in each medium; LB cultures were dominated by the H482Y mutation (27/53 or 51%) whereas SMM Asn cultures were dominated by the S487L mutation (24/51 or 47%). Furthermore, we found through competition experiments that the relative fitness of the S487L mutant was significantly higher in SMM Asn than in LB medium. We therefore conclude that both the spectrum of Rif R mutations in the B. subtilis rpoB gene and the fitness of resulting mutants to be influenced by the growth environment. Importance The rpoB gene encodes the beta subunit of RNA polymerase, and mutations in rpoB are key determinants of resistance to the clinically important antibiotic rifampicin. We show here that the spectrum of mutations in Bacillus subtilis rpoB depends on the medium in which the cells are cultivated. The results show that not only does the growth environment play a role in natural selection and fitness, but it also influences the probability of mutation at particular bases within the target gene.

scholarly journals Brucellosis Reemergence after a Decade of Quiescence in Palestine, 2015-2017: a Seroprevalence and Molecular Characterization Study

2021 ◽  
Author(s):  
Bessan Aljanazreh ◽  
Khaled Alzatari ◽  
Asmaa Tamimi ◽  
Mohammad Alsaafeen ◽  
Waheed Hassouneh ◽  
...  
Keyword(s):  
Genetic Relatedness ◽  
Control Program ◽  
Rpob Gene ◽  
World Health ◽  
Rifampicin Resistance ◽  
Resistance Mutations ◽  
Program Outcomes ◽  
Serological Tests ◽  
Control Programs ◽  
Health Organization

Brucellosis is an endemic disease in many developing countries and ranked by the World Health Organization among the top seven “neglected zoonoses”. Although a Palestinian brucellosis control program was launched in 1998, the disease reemerged after 2012. Interestingly, a similar reemerging pattern was reported in the neighboring Israeli regions. The aim of this work was to characterize the reemerging strains and delineate their genetic relatedness. During 2015-2017, blood samples from 1324 suspected patients were analyzed using two serological tests. Seropositive samples were cultured, and their DNAs were analyzed by different genetic markers to determine the involved Brucella species and rule out any possible involvement of the Rev.1 vaccine strain. The rpoB gene was sequenced from 9 isolates to screen for rifampicin-resistance mutations. Multi Locus VNTR Analysis (MLVA-16) was used for genotyping the isolates. The molecular analysis showed that all isolates were B. melitensis strains unrelated to the Rev.1 vaccine. The rpoB gene sequences showed four single nucleotide variations (SNVs) not associated with rifampicin resistance. MLVA-16 analysis clustered the isolates into 22 unique genotypes that belong to the East Mediterranean lineage. Altogether, our findings show that the reemergence of brucellosis was due to B. melitensis strains of local origin, the Palestinian and Israeli control programs’ weaknesses could be a major factor behind the reemergence of the disease. However, other socioeconomic and environmental factors must be investigated. Moreover, strengthening brucellosis control programs and enhancing cooperation between all stakeholders is essential to ensure long-term program outcomes to fight brucellosis.

scholarly journals The Spectrum of Spontaneous Rifampin Resistance Mutations in the rpoB Gene of Bacillussubtilis 168 Spores Differs from That of Vegetative Cells and Resembles That of Mycobacterium tuberculosis

2002 ◽  
Vol 184 (17) ◽  
pp. 4936-4940 ◽  
Author(s):  
Wayne L. Nicholson ◽  
Heather Maughan
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Bacillus Subtilis ◽  
Rpob Gene ◽  
Β Subunit ◽  
Resistance Mutations ◽  
New Mutation ◽  
Gene Encoding ◽  
Vegetative Cells ◽  
Dormant Cells ◽  
Rifampin Resistance

ABSTRACT Mutations causing rifampin resistance in vegetative cells of Bacillus subtilis 168 have thus far been mapped to a rather restricted set of alterations at either Q469 or H482 within cluster I of the rpoB gene encoding the β subunit of RNA polymerase. In this study, we demonstrated that spores of B. subtilis 168 exhibit a spectrum of spontaneous rifampin resistance mutations distinct from that of vegetative cells. In addition to the rpoB mutations Q469K, Q469R, and H482Y previously characterized in vegetative cells, we isolated a new mutation of rpoB, H482R, from vegetative cells. Additional new rifampin resistance mutations arising from spores were detected at A478N and most frequently at S487L. The S487L change is the predominant change found in rpoB mutations sequenced from rifampin-resistant clinical isolates of Mycobacterium tuberculosis. The observations are discussed in terms of the underlying differences of the DNA environment within dormant cells and vegetatively growing cells.

scholarly journals Rifampicin-Resistance Mutations in the rpoB Gene in Bacillus velezensis CC09 have Pleiotropic Effects

2017 ◽  
Vol 08 ◽  
Author(s):  
Xun-Chao Cai ◽  
Huan Xi ◽  
Li Liang ◽  
Jia-Dong Liu ◽  
Chang-Hong Liu ◽  
...  
Keyword(s):  
Rpob Gene ◽  
Pleiotropic Effects ◽  
Rifampicin Resistance ◽  
Resistance Mutations ◽  
Bacillus Velezensis

Emergence of Heteroresistance Mycobacterium Tuberculosis in Saudi Arabia

2020 ◽  
Vol 20 (4) ◽  
pp. 491-494 ◽  
Author(s):  
Eltayib H. Ahmed Abakur ◽  
Tarig M.S. Alnour ◽  
Faisel Abuduhier ◽  
Fahad M.A. Albalawi ◽  
Khalid A.S. Alfifi
Keyword(s):  
Saudi Arabia ◽  
Mycobacterium Tuberculosis ◽  
Clinical Specimen ◽  
Rpob Gene ◽  
Rifampicin Resistance ◽  
Resistant Bacteria ◽  
Kingdom Of Saudi Arabia ◽  
Preliminary Stage ◽  
The North ◽  
Genotype Mtbdrplus

Purpose: Heteroresistant Mycobacterium tuberculosis (MTB) is defined as a group of drug-susceptible and resistant bacteria in a single clinical specimen from tuberculosis (TB) patients. Heteroresistance of MTB is considered a preliminary stage to full resistance. The present study aimed to determine the heteroresistance in Mycobacterium tuberculosis in Tabuk province, in the north of the Kingdom of Saudi Arabia. Method: GenoType MTBDRplus assay was used to determine mutations associated with isoniazid and rifampicin resistance. Results: A total number of 46 confirmed M. tuberculosis positive sputum samples were scanned for heteroresistance. The present study revealed 3 (6.5%) heteroresistant mutations to either rpoB gene alone, 2 (4.4%) to rpoB and 1 (2.2%) to inhA genes. Conclusion: The detection of heteroresistant mutations could guide the initiation of an appropriate regimen of treatment.

scholarly journals Sequence analysis of the rifampicin resistance determining region (RRDR) of rpoB gene in multidrug resistance confirmed and newly diagnosed tuberculosis patients of Punjab, Pakistan

PLoS ONE ◽  
2017 ◽  
Vol 12 (8) ◽  
pp. e0183363 ◽  
Author(s):  
Salma Hameed ◽  
Kartyk Moganeradj ◽  
Nasir Mahmood ◽  
Timothy D. McHugh ◽  
Muhammad Nawaz Chaudhry ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Sequence Analysis ◽  
Rpob Gene ◽  
Rifampicin Resistance ◽  
Newly Diagnosed ◽  
Tuberculosis Patients
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