Browsing by Author "Xet-Mull, Ana M"

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    A Cluster of Nontuberculous Mycobacterial Tenosynovitis Following Hurricane Relief Efforts.
    (Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2021-06) Turner, Nicholas A; Sweeney, Mollie I; Xet-Mull, Ana M; Storm, Jeremy; Mithani, Suhail K; Jones, David B; Miles, Jeremy J; Tobin, David M; Stout, Jason E

    Background

    Nontuberculous mycobacteria (NTM) are a rare cause of infectious tenosynovitis of the upper extremity. Using molecular methods, clinical microbiology laboratories are increasingly reporting identification down to the species level. Improved methods for speciation are revealing new insights into the clinical and epidemiologic features of rare NTM infections.

    Methods

    We encountered 3 cases of epidemiologically linked upper extremity NTM tenosynovitis associated with exposure to hurricane-damaged wood. We conducted whole-genome sequencing to assess isolate relatedness followed by a literature review of NTM infections that involved the upper extremity.

    Results

    Despite shared epidemiologic risk, the cases were caused by 3 distinct organisms. Two cases were rare infections caused by closely related but distinct species within the Mycobacterium terrae complex that could not be differentiated by traditional methods. The third case was caused by Mycobacterium intracellulare. An updated literature review that focused on research that used modern molecular speciation methods found that several species within the M. terrae complex are increasingly reported as a cause of upper extremity tenosynovitis, often in association with environmental exposures.

    Conclusions

    These cases illustrate the importance of molecular methods for speciating phenotypically similar NTM, as well as the limitations of laboratory-based surveillance in detecting point-source outbreaks when the source is environmental and may involve multiple organisms.
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    Annotated Genome Sequences of 16 Lineage 4 Mycobacterium tuberculosis Strains from Guatemala.
    (Genome announcements, 2018-02) Saelens, Joseph W; Lau-Bonilla, Dalia; Moller, Anneliese; Xet-Mull, Ana M; Medina, Narda; Guzmán, Brenda; Calderón, Maylena; Herrera, Raúl; Stout, Jason E; Arathoon, Eduardo; Samayoa, Blanca; Tobin, David M
    Whole-genome sequencing has resulted in new insights into the phylogeography of Mycobacterium tuberculosis However, only limited genomic data are available from M. tuberculosis strains in Guatemala. Here we report 16 complete genomes of clinical strains belonging to the Euro-American lineage 4, the most common lineage found in Guatemala and Central America.
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    Search for microRNAs expressed by intracellular bacterial pathogens in infected mammalian cells.
    (PLoS One, 2014) Furuse, Yuki; Finethy, Ryan; Saka, Hector A; Xet-Mull, Ana M; Sisk, Dana M; Smith, Kristen L Jurcic; Lee, Sunhee; Coers, Jörn; Valdivia, Raphael H; Tobin, David M; Cullen, Bryan R
    MicroRNAs are expressed by all multicellular organisms and play a critical role as post-transcriptional regulators of gene expression. Moreover, different microRNA species are known to influence the progression of a range of different diseases, including cancer and microbial infections. A number of different human viruses also encode microRNAs that can attenuate cellular innate immune responses and promote viral replication, and a fungal pathogen that infects plants has recently been shown to express microRNAs in infected cells that repress host cell immune responses and promote fungal pathogenesis. Here, we have used deep sequencing of total expressed small RNAs, as well as small RNAs associated with the cellular RNA-induced silencing complex RISC, to search for microRNAs that are potentially expressed by intracellular bacterial pathogens and translocated into infected animal cells. In the case of Legionella and Chlamydia and the two mycobacterial species M. smegmatis and M. tuberculosis, we failed to detect any bacterial small RNAs that had the characteristics expected for authentic microRNAs, although large numbers of small RNAs of bacterial origin could be recovered. However, a third mycobacterial species, M. marinum, did express an ∼ 23-nt small RNA that was bound by RISC and derived from an RNA stem-loop with the characteristics expected for a pre-microRNA. While intracellular expression of this candidate bacterial microRNA was too low to effectively repress target mRNA species in infected cultured cells in vitro, artificial overexpression of this potential bacterial pre-microRNA did result in the efficient repression of a target mRNA. This bacterial small RNA therefore represents the first candidate microRNA of bacterial origin.
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    Whole genome sequencing identifies circulating Beijing-lineage Mycobacterium tuberculosis strains in Guatemala and an associated urban outbreak.
    (Tuberculosis (Edinb), 2015-12) Saelens, Joseph W; Lau-Bonilla, Dalia; Moller, Anneliese; Medina, Narda; Guzmán, Brenda; Calderón, Maylena; Herrera, Raúl; Sisk, Dana M; Xet-Mull, Ana M; Stout, Jason E; Arathoon, Eduardo; Samayoa, Blanca; Tobin, David M
    Limited data are available regarding the molecular epidemiology of Mycobacterium tuberculosis (Mtb) strains circulating in Guatemala. Beijing-lineage Mtb strains have gained prevalence worldwide and are associated with increased virulence and drug resistance, but there have been only a few cases reported in Central America. Here we report the first whole genome sequencing of Central American Beijing-lineage strains of Mtb. We find that multiple Beijing-lineage strains, derived from independent founding events, are currently circulating in Guatemala, but overall still represent a relatively small proportion of disease burden. Finally, we identify a specific Beijing-lineage outbreak centered on a poor neighborhood in Guatemala City.