Addy Cecilia Helguera-Repetto

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The prevalence of infections with Mycobacterium tuberculosis (MTb) and nontuberculous mycobacteria (NTM) species in HIV-infected patients in Mexico is unknown. The aims of this study were to determine the frequency of MTb and NTM species in HIV-infected patients from Mexico City, to evaluate the genotypic diversity of the Mycobacterium tuberculosis complex(More)
This study examined the frequency of occurrence of non-tuberculous mycobacteria (NTM) in potable water samples from a main trauma hospital in Mexico City. Sixty-nine potable water samples were collected, 23 from each source: cistern, kitchen tap and bathroom showers. Of the 69 samples, 36 harboured NTM species. Twenty-nine of the 36 isolates were(More)
Nontuberculous mycobacteria (NTM) are environmental opportunistic pathogens found in natural and human-engineered waters, including drinking water distribution systems and household plumbing. This pilot study examined the frequency of occurrence of NTM in household potable water samples in Mexico City. Potable water samples were collected from the “main(More)
Major differences regarding the pathology and host immune response of the Beijing and Canettii genotypes of Mycobacterium tuberculosis have been reported; however, studies on the genetic expression of these genotypes during in vitro dormancy are scarce. This study examined the expression of five cell-cycle-related genes and two dormancy-related genes in M.(More)
The slow-growing Mycobacterium celatum is known to have two different 16S rRNA gene sequences. This study confirms the presence of two rrn operons and describes their organization. One operon (rrnA) was found to be located downstream from murA and the other (rrnB) was found downstream from tyrS. The promoter regions were sequenced, and also the intergenic(More)
Nontuberculous mycobacteria (NTM) have recently been recognized as important species that cause disease even in immunocompetent individuals. The mechanisms that these species use to infect and persist inside macrophages are not well characterised. To gain insight concerning this process we used THP-1 macrophages infected with M. abscessus, M. fortuitum, M.(More)
The study of the in vitro cell growth of mycobacteria still remains a fastidious, difficult, and time-consuming procedure. In addition, assessing mycobacterial growth in the laboratory is often complicated by cell aggregation and slow growth-rate. We now report that the use of a stainless steel spring in the culture led to an absence of large cell clumps,(More)
The aims of this study were to evaluate the microbiological quality and the occurrence of nontuberculous mycobacteria (NTM) in a variety of salads and sprouts from supermarkets and street vendors in Mexico City. Aerobic-mesophilic bacteria (AMB) were present in 100% of RTE-salads samples; 59% of samples were outside guidelines range (>5.17 log10 CFU per g).(More)
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(More)
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. All(More)
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