Novel Populations of Under Hypoxia and Starvation: Some Insights on Cell Viability and Morphological Changes.

The general features of the shift to a dormant state in mycobacterial species include several phenotypic changes, reduced metabolic activities, and increased resistance to host and environmental stress conditions. In this study, we aimed to provide novel insights into the viability state and morphological changes in dormant that contribute to its long-term survival under starvation or hypoxia. To this end, we conducted assays to evaluate cell viability, morphological changes and gene expression.

Design of a Multi-Epitope Vaccine against Tuberculosis from PE_PGRS49 and PE_PGRS56 Proteins by Reverse Vaccinology.

Tuberculosis is a disease caused by , representing the second leading cause of death by an infectious agent worldwide. The available vaccine against this disease has insufficient coverage and variable efficacy, accounting for a high number of cases worldwide. In fact, an estimated third of the world's population has a latent infection.

Organization and Characterization of the Promoter Elements of the rRNA Operons in the Slow-Growing Pathogen .

The slow-growing, nontuberculous mycobacterium possesses two rRNA operons, and , located downstream from the and genes, respectively. Here, we report the sequence and organization of the promoter regions of these two operons. In the operon, transcription can be initiated from the two promoters, named P1 and PCL1, while in , transcription can only start from one, called P1 .

The Flp type IV pilus operon of is expressed upon interaction with macrophages and alveolar epithelial cells.

The genome of () harbors the genetic machinery for assembly of the Fimbrial low-molecular-weight protein (Flp) type IV pilus. Presumably, the Flp pilus is essential for pathogenesis. However, it remains unclear whether the pili genes are transcribed in culture or during infection of host cells.

The Lack of the TetR-Like Repressor Gene _ () May Help Mycobacteria Overcome Intracellular Redox Stress and Survive Longer Inside Macrophages When Surrounded by a Lipid Environment.

Mycobacteria, like other microorganisms, survive under different environmental variations by expressing an efficient adaptive response, oriented by regulatory elements, such as transcriptional repressors of the TetR family. These repressors in mycobacteria also appear to be related to cholesterol metabolism. In this study, we have evaluated the effect of a fatty acid (oleic-palmitic-stearic)/cholesterol mixture on some phenotypic and genotypic characteristics of a tetR-mutant strain ( mutated gene) of BCG, a homologous of of .

cAMP Receptor Protein Positively Regulates the Expression of Genes Involved in the Biosynthesis of Tilivalline Cytotoxin.

is a resident of the human gut. However, certain toxigenic strains exist that secrete the nonribosomal peptide tilivalline (TV) cytotoxin. TV is a pyrrolobenzodiazepine that causes antibiotic-associated hemorrhagic colitis (AAHC).

Occurrence of Nontuberculous Mycobacteria, Salmonella, Listeria monocytogenes, and Staphylococcus aureus in Artisanal Unpasteurized Cheeses in the State of Michoacan, Mexico.

Abstract: This study investigated the presence of nontuberculous mycobacteria (NTM) for the first time in two types of unpasteurized fresh cheese produced in the state of Michoacan, Mexico. We tested for this pathogen, along with the others, to broaden the study of microbiological quality in 60 samples of cheese, 30 fresh and 30 Adobera, which were collected from six artisanal cheese factories (ACFs). The hygienic conditions of these establishments and the practices of cheese manufacture were generally poor.

Short Disordered Epitope of CRTAM Ig-Like V Domain as a Potential Target for Blocking Antibodies.

Class-I Restricted T Cell-Associated Molecule (CRTAM) is a protein that is expressed after T cell activation. The interaction of CRTAM with its ligand, nectin-like 2 (Necl2), is required for the efficient production of IL-17, IL-22, and IFNγ by murine CD4 T cells, and it plays a role in optimal CD8 T and NK cell cytotoxicity. CRTAM promotes the pro-inflammatory cytokine profile; therefore, it may take part in the immunopathology of autoimmune diseases such as diabetes type 1 or colitis.

Two Type VI Secretion Systems of Are Required for Bacterial Competition, Cell Adherence, and Intestinal Colonization.

has emerged as an opportunistic pathogen in healthcare-associated infections. Analysis of the genomic sequences of several strains revealed the presence of genes that code for expression of at least one type VI secretion system (T6SS). Here, we report that strain ATCC 13047 codes for two functional T6SS named T6SS-1 and T6SS-2.

Neonatal Sepsis Diagnosis Decision-Making Based on Artificial Neural Networks.

Neonatal sepsis remains difficult to diagnose due to its non-specific signs and symptoms. Traditional scoring systems help to discriminate between septic or not patients, but they do not consider every single patient particularity. Thus, the purpose of this study was to develop an early- and late-onset neonatal sepsis diagnosis model, based on clinical maternal and neonatal data from electronic records, at the time of clinical suspicion.

Molecular Characterization of SehB, a Type II Antitoxin of Serotype Typhimurium: Amino Acid Residues Involved in DNA-Binding, Homodimerization, Toxin Interaction, and Virulence.

serotype Typhimurium is a bacterium that causes gastroenteritis and diarrhea in humans. The genome of Typhimurium codes for diverse virulence factors, among which are the toxin-antitoxin (TA) systems. SehAB is a type II TA, where SehA is the toxin and SehB is the antitoxin.

Bacteriological quality of bottled water obtained from Mexico City small water purification plants: Incidence and identification of potentially pathogenic nontuberculous mycobacteria species.

The aim of this study was to determine the bacteriological quality of bottled water samples obtained from small purification plants located in Mexico City and to identify potentially pathogenic nontuberculous mycobacteria (NTM) species found in these samples. All 111 samples analyzed were positive for aerobic mesophilic bacteria (AMB) and 46 (41.4%) did not comply with Mexico's Official Guidelines.

Hypoxia Is Not a Main Stress When Is in a Dormancy-Like Long-Chain Fatty Acid Environment.

The capacity of () to sense, respond and adapt to a variable and hostile environment within the host makes it one of the most successful human pathogens. During different stages of infection, is surrounded by a plethora of lipid molecules and current evidence points out the relevance of fatty acids during the infectious process. In this study, we have compared the transcriptional response of to hypoxia in cultures supplemented with a mix of even long-chain fatty acids or dextrose as main carbon sources.

Identification and biofilm development by a new fungal keratitis aetiologic agent.

Background: In recent years, human keratitis caused by fungal plant pathogens has become more common. Biofilm is a structure that confers adaptations and virulence to fungi in keratitis. Neoscytalidium spp.

Genetic diversity of drug and multidrug-resistant Mycobacterium tuberculosis circulating in Veracruz, Mexico.

Background: Mexico is one of the most important contributors of drug and multidrug-resistant tuberculosis in Latin America; however, knowledge of the genetic diversity of drug-resistant tuberculosis isolates is limited.

Methods: In this study, the genetic structure of 112 Mycobacterium tuberculosis strains from the southeastern Mexico was determined by spoligotyping and 24-loci MIRU-VNTRs.

Findings: The results show eight major lineages, the most of which was T1 (24%), followed by LAM (16%) and H (15%).

The transcriptome of Mycobacterium tuberculosis in a lipid-rich dormancy model through RNAseq analysis.

Tuberculosis (TB) is currently the number one killer among infectious diseases worldwide. Lipids are abundant molecules during the infectious cycle of Mycobacterium tuberculosis (Mtb) and studies better mimicking its actual metabolic state during pathogenesis are needed. Though most studies have focused on the mycobacterial lipid metabolism under standard culture conditions, little is known about the transcriptome of Mtb in a lipid environment.

Comparative proteomic profiles reveal characteristic Mycobacterium tuberculosis proteins induced by cholesterol during dormancy conditions.

Cholesterol has been reported to play an important role during Mycobacterium tuberculosis infection and during its dormant state inside the host. We present the determination of proteomic profiles of M. tuberculosis H37Rv in the presence of cholesterol as the sole carbon source under exponential growth and in two in vitro dormancy phases (NRP1 and NRP2).

In vitro activity of bedaquiline against rapidly growing nontuberculous mycobacteria.

Bedaquiline (BDQ) has been proven to be effective in the treatment of multidrug-resistant tuberculosis. We hypothesized that BDQ could be a potential agent to treat nontuberculous mycobacterial (NTM) infection. The objective of this study was to evaluate the in vitro activity of BDQ against rapidly growing mycobacteria by assessing the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) against 18 NTM strains.

The sigma factor SigD of Mycobacterium tuberculosis putatively enhances gene expression of the septum site determining protein under stressful environments.

This work examined the expression of the septum site determining gene (ssd) of Mycobacterium tuberculosis CDC1551 and its ∆sigD mutant under different growing conditions. The results showed an up-regulation of ssd during stationary phase and starvation conditions, but not during in vitro dormancy, suggesting a putative role for SigD in the control of ssd expression mainly under lack-of-nutrients environments. Furthermore, we elucidated a putative link between ssd expression and cell elongation of bacilli at stationary phase.

Detection of a Putative TetR-Like Gene Related to BCG Growth in Cholesterol Using a -Transposon Mutagenesis System.

transposition is a powerful genetic tool for identifying mycobacterial virulence genes and studying virulence factors in relation to the host. Transposon shuttle mutagenesis is a method for constructing stable insertions in the genome of different microorganisms including mycobacteria. Using an IS derivative, we have constructed the Tn, a transposon containing a promoterless green fluorescent protein () gene.

Additional regulatory activities of MrkH for the transcriptional expression of the Klebsiella pneumoniae mrk genes: Antagonist of H-NS and repressor.

Klebsiella pneumoniae is a common opportunistic pathogen causing nosocomial infections. One of the main virulence determinants of K. pneumoniae is the type 3 pilus (T3P).

Cholesterol plays a larger role during Mycobacterium tuberculosis in vitro dormancy and reactivation than previously suspected.

It is known that cholesterol plays a key role for Mycobacterium tuberculosis (Mtb) adaptation and survival within the host, thus contributing to the establishment of dormancy. It has been extensively demonstrated that fatty acids are the main energy source of Mtb during infection and dormancy, and it has been proposed that these molecules are implicated in reactivation of bacilli from a dormant state. We used in vitro models to analyze Mtb gene expression during dormancy and reactivation when fatty acids and cholesterol are the unique carbon source in the media.

Microbiological Quality and Occurrence of Nontuberculous Mycobacteria in Fresh-Squeezed Orange Juice Samples Purchased from Street Vendors in Mexico City.

Nontuberculous mycobacteria (NTM) are potentially pathogenic agents commonly found in a natural ecosystem. For this reason, food is considered another source of NTM transmission for humans. The aims of this study were to evaluate the microbiological quality and the occurrence of NTM in fresh-squeezed orange juice samples purchased from street vendors.

"Genetic regulation of Mycobacterium tuberculosis in a lipid-rich environment".

Tuberculosis (TB) remains as one of the leading causes of morbidity and mortality among infectious diseases worldwide. Although lipids (mainly fatty acids and cholesterol) have been reported to play an important role during active and latent infection of M. tuberculosis, there are other molecular aspects of bacterial response to those substrates that are not fully understood, involving gene regulation background.

Molecular epidemiology of Mycobacterium tuberculosis in Baja California, Mexico: A result of human migration?

The State of Baja California (BC) exhibits the highest incidence and prevalence rates of tuberculosis (TB), and multidrug-resistant TB (MDR-TB) in Mexico. However information about the circulation of M. tuberculosis lineages in BC and Mexico as a whole is limited.