Difference of MreBCD Complex Interactome in Salmonella Typhimurium ST19 and ST213 Genotypes on Pathogenesis and Stress Response Pathways.

BACKGROUND: Salmonella enterica is the etiological agent of salmonellosis, with a high infection rate worldwide in Mexico, ST213 genotype of S. enterica ser. Typhimurium is displacing the ancestral ST19 genotype. Bacterial cytoskeleton protein complex MreBCD plays an important role in S. enterica pathogenesis, but underlying mechanisms are unknown. RESULTS: In this study, 106 interactions among MreBCD and 15 proteins from S. Typhimurium Pathogenicity Islands 1 (SP-I) and 2 (SP-2) involved in both bacterial virulence and stress response were predicted in ST213 and ST19 genotypes, of which 12 interactions were confirmed in vitro. In addition, gene cluster analysis in 100 S. Typhimurium genomes was performed for these genes. RESULTS AND CONCLUSION: The in silico and in vitro results showed a novel MreBCD interactome involved in regulating pathogenesis and stress response through interactions with virulence factors located at SPI-1 and SPI-2. Furthermore, both pseudogene presence and sequence variations in four tested proteins between genotypes resulted in differential interaction patterns involved in Salmonella motility and survival in eukaryotic cells, which could explain the replacement of ST19 by ST213 in Mexico.

The Polycyclic Aromatic Hydrocarbon (PAH) degradation activities and genome analysis of a novel strain Stenotrophomonas sp. Pemsol isolated from Mexico.

BACKGROUND: Stenotrophomonas are ubiquitous gram-negative bacteria, which can survive in a wide range of environments. They can use many substances for their growth and are known to be intrinsically resistant to many antimicrobial agents. They have been tested for biotechnological applications, bioremediation, and production of antimicrobial agents. METHOD: Stenotrophomonas sp. Pemsol was isolated from a crude oil contaminated soil. The capability of this isolate to tolerate and degrade polycyclic aromatic hydrocarbons (PAH) such as anthraquinone, biphenyl, naphthalene, phenanthrene, phenanthridine, and xylene was evaluated in Bushnell Hass medium containing PAHs as the sole carbon sources. The metabolites formed after 30-day degradation of naphthalene by Pemsol were analyzed using Fourier Transform Infra-red Spectroscopic (FTIR), Ultra-Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS) and Gas Chromatography-Mass Spectrometry (GC-MS). The genome of Pemsol was also sequenced and analyzed. RESULTS: Anthraquinone, biphenyl, naphthalene, phenanthrene, and phenanthridine except xylene can be used as sole carbon sources for Pemsol's growth in Bushnell Hass medium. The degradation of naphthalene at a concentration of 1 mg/mL within 30 days was tested. A newly formed catechol peak and the disappearance of naphthalene peak detected on the UPLC-MS, and GC-MS analyses spectra respectively confirmed the complete degradation of naphthalene. Pemsol does not produce biosurfactant and neither bio-emulsify PAHs. The whole genome was sequenced and assembled into one scaffold with a length of 4,373,402 bp. A total of 145 genes involved in the degradation of PAHs were found in its genome, some of which are Pemsol-specific as compared with other 11 Stenotrophomonas genomes. Most specific genes are located on the genomic islands. Stenotrophomonas sp. Pemsol's possession of few genes that are associated with bio-emulsification gives the genetic basis for its inability to bio-emulsify PAH. A possible degradation pathway for naphthalene in Pemsol was proposed following the analysis of Pemsol's genome. ANI and GGDH analysis indicated that Pemsol is likely a new species of Stenotrophomonas. It is the first report on a complete genome sequence analysis of a PAH-degrading Stenotrophomonas. Stenotrophomonas sp. Pemsol possesses features that make it a good bacterium for genetic engineering and will be an excellent tool for the remediation of crude oil or PAH-contaminated soil.

Post-elimination surveillance in formerly onchocerciasis endemic focus in Southern Mexico.

BACKGROUND: All formerly endemic communities of the Southern Chiapas focus of onchocerciasis in Mexico were treated with ivermectin until parasite transmission was eliminated by 2015. Transmission of onchocerciasis did not resume during a period of three years (2012-2014) following the final distribution of ivermectin in 2011; it was thus concluded that transmission remained undetectable without intervention. WHO thus declared the elimination of transmission of onchocerciasis from Mexico in 2015. METHODOLOGY/PRINCIPAL FINDINGS: From 2016 to the present, post-elimination surveillance (PES) based on examination for suspected onchocercomas was performed in the former Southern Chiapas focus. Each year, over 60% of the total population (range = 85,347-104,106 individuals) of the formerly endemic communities were examined for onchocercomas. Thirty-four individuals were found harboring suspected onchocercomas in the PES surveys conducted from 2016-2019. Of these, one female of 7 years of age who had immigrated from a formerly endemic focus, harbored an infertile (sterile) female in the suspected onchocercoma; all others were negative. Skin biopsy assessments were performed from March through May 2017 in three communities where the female resided. None of the 83 individuals of the three communities examined by skin biopsy were mf positive. Similarly, none of the biopsies from the individuals were found to contain parasite DNA when tested by polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA). CONCLUSIONS/SIGNIFICANCE: These provide support to the conclusion that onchocerciasis has been eliminated from Mexico.

Genes de virulencia en Aeromonas spp. (Aeromonadales: Aeromonadaceae) aisladas de Oreochromis spp. (Perciformes: Cichlidae) para consumo humano en México / Virulence genes in Aeromonas spp. (Aeromonadales: Aeromonadaceae) isolated from Oreochromis spp. (Perciformes: Cichlidae) destined for human consumption in Mexico

Resumen Las especies del género Aeromonas se encuentran ampliamente distribuidas en ecosistemas acuáticos, son bacilos Gram negativas, oxidasa positivas y fermentadoras de glucosa que han sido consideradas patógenas emergentes en humanos. Por otra parte, Aeromonas pertenece a la microbiota normal de los peces, no obstante, estos microorganismos poseen una diversidad de factores de virulencia responsables de una variedad de infecciones en humanos, principalmente de tipo gastrointestinal. La presencia de Aeromonas en productos destinados a consumo de alta demanda comercial como la tilapia genera preocupación sanitaria por el potencial patogénico que posee esta bacteria. En este contexto, identificar genes de virulencia presentes en cepas de Aeromonas aisladas en Oreochromis spp. para consumo humano en Reynosa, Tamaulipas, México; es de importancia ante la escasez de estudios moleculares al respecto en la zona. En el presente estudio se analizó el potencial patogénico de 15 cepas de Aeromonas previamente identificadas molecularmente mediante PCR y secuenciación, procedentes de Oreochromis spp. Mediante PCR se analizaron seis genes de virulencia (alt, ast, aerA, hlyA, gcat y stx1) y las cepas utilizadas como control fueron: Aeromonas hydrophila subsp. hydrophila ATCC 7966, Aeromonas caviae 429865 INP, Escherichia coli O157:H7 y Escherichia coli K12. El 100 % (n = 15) de las cepas presentaron al menos un gen de virulencia, el gen aerA se detectó en 86.66 % de las cepas analizadas, mientras que los genes ast y stx1 no fueron identificados. Se encontró que las cepas de Aeromonas presentaban genes asociados en una misma cepa: aerA/gcat, alt/aerA, alt/ aerA/gcat/hlyA y alt/aerA/gcat, de los cuales aerA/gcat se observó con mayor frecuencia y principalmente en A. veronii, mientras que, A. hydrophila presentó el mayor número de asociaciones de genes de virulencia. Estos hallazgos indican que las cepas de Aeromonas aisladas en Oreochromis spp. tienen el potencial de causar enfermedades en humanos. Por lo tanto, es necesario proporcionar información sobre esta bacteria emergente, para tratar y controlar eficazmente cualquier posible evento epidemiológico causado por la misma.(AU)

Abstract The genus Aeromonas are widely distributed in aquatic ecosystems are Gram-negative rods, oxidase-positive, and glucose-fermenting, considered emerging pathogens in humans. Aeromonas belongs to the fish microbiota, these microorganisms have a diversity of virulence factors responsible for a variety of infections in humans mainly gastrointestinal diseases. The presence of Aeromonas in products intended for consumption with high commercial demand such as tilapia generates sanitary concern due to the pathogenic potential of this bacteria. In this context, identification of virulence genes in strains of Aeromonas isolated in Oreochromis spp. intended for human consumption in Reynosa, Tamaulipas, Mexico is important due to the lack of molecular studies in this geographical area. In the present study the pathogenic potential of 15 strains of Aeromonas (A. veronii, A. hydrophila and A. schubertii) from Oreochromis spp. for human consumption were analyzed. Through PCR six virulence genes were analyzed (alt, ast, aerA, hlyA, gcat and stx1) and the strains used as control were: Aeromonas hydrophila subsp. hydrophila ATCC 7966, Aeromonas caviae 429865 INP, Escherichia coli O157: H7 and Escherichia coli K12. El 100 % (n = 15) of the strains harbored at least one virulence gene, aerA gene was detected in 86.66 % of the analyzed strains, while ast and stx1 genes were not identified. Moreover, Aeromonas strains had associated genes in the same strain: aerA / gcat, alt / aerA, alt / aerA / gcat / hlyA and alt / aerA / gcat, of which aerA / gcat were observed mostly in A. veronii, while A. hydrophila had the highest associations. These findings indicate that the strains of Aeromonas isolated in Oreochromis spp. have the potential to cause human diseases, and therefore, this species used as food, could be a vehicle for infections caused by Aeromonas. It also allows to provide information on this emerging microorganism to effectively treat and control any epidemiological event caused by Aeromonas spp. in the future.(AU)

Biochemical and Biophysical Characterization of the Enolase from Helicobacter pylori.

Enolase, which catalyses the conversion of 2-phospho-D-glycerate to phosphoenolpyruvate, is an important enzyme in the classic glycolysis pathway in cells. Enolase is highly conserved in organisms from bacteria to humans, indicating its importance in cells. Thus, enolase is a good target for developing new drugs. In the last decade, new functions of this enzyme have been found. Helicobacter pylori is a common human pathogen that causes gastric diseases and even gastric cancer. In this study, the sequence of H. pylori enolase (HpEno) was analysed; the conservation (at least partial) of binding sites for cofactor, plasminogen, and host extracellular RNA, as well as catalytic site, indicates that HpEno should be capable of performing the functions. Recombinant HpEno was overexpressed and purified from E. coli. Compared to the enolases from other species, HpEno had similar characteristics for its secondary structure. The temperature-induced profiles indicate that HpEno is quite stable to temperature, compared to other homologs. Regarding the kinetics of the unfolding reaction, we found that the activation enthalpy associated with the thermal unfolding reaction is equivalent to the reported activation enthalpy for yeast enolase, indicating a similar scaffold and kinetic stability. Although a wide range of experimental conditions were assayed, it was not possible to detect any enzymatic activity of HpEno. To prove the lack of activity, still a much wider range of experiments should be carried out.

Evaluation of a community-based trapping program to collect Simulium ochraceum sensu lato for verification of onchocerciasis elimination.

BACKGROUND: Collection of the black fly vectors of onchocerciasis worldwide relies upon human landing collections. Recent studies have suggested that the Esperanza Window Trap baited with a human scent lure and CO2 had the potential to replace human hosts for the collection of Simulium ochraceum sensu lato in Southern Chiapas focus, Mexico. The feasibility of utilizing these traps in a community-based approach for the collection of S. ochraceum s.l. was evaluated. METHODOLOGY/PRINCIPAL FINDINGS: Local residents of a formerly endemic extra-sentinel community for onchocerciasis were trained to carry out collections using the traps. The residents operated the traps over a 60-day period and conducted parallel landing collections, resulting in a total of 28,397 vector black flies collected. None of the flies collected were found to contain parasite DNA when tested by a polymerase chain reaction assay targeting a parasite specific sequence, resulting in a point estimate of infection in the vectors of zero, with an upper bound of the 95% confidence interval 0.13 per 2,000. This meets the accepted criterion for demonstrating an interruption of parasite transmission. CONCLUSIONS/SIGNIFICANCE: These data demonstrate that Esperanza Window Traps may be effectively operated by minimally trained residents of formerly endemic communities, resulting in the collection of sufficient numbers of flies to verify transmission interruption of onchocerciasis. The traps represent a viable alternative to using humans as hosts for the collection of vector flies as part of the verification of onchocerciasis elimination.

Interruption of transmission of Onchocerca volvulus in the Southern Chiapas Focus, México.

BACKGROUND: The Southern Chiapas focus of onchocerciasis in Southern Mexico represents one of the major onchocerciasis foci in Latin America. All 559 endemic communities of this focus have undergone semi-annual mass treatment with ivermectin since 1998. In 50 communities of this focus, ivermectin frequency shifted from twice to four times a year in 2003; an additional 113 communities were added to the quarterly treatment regimen in 2009 to achieve a rapid suppression of transmission. METHODOLOGY/PRINCIPAL FINDINGS: In-depth epidemiologic and entomologic assessments were performed in six sentinel communities (which had undergone 2 rounds of ivermectin treatment per year) and three extra-sentinel communities (which had undergone 4 rounds of ivermectin treatment per year). None of the 67,924 Simulium ochraceum s.l. collected from this focus during the dry season of 2011 were found to contain parasite DNA when tested by polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA), resulting in an upper bound of the 95% confidence interval (95%-ULCI) of the infective rate in the vectors of 0.06/2,000 flies examined. Serological assays testing for Onchocerca volvulus exposure conducted on 4,230 children 5 years of age and under (of a total population of 10,280 in this age group) revealed that 2/4,230 individuals were exposed to O. volvulus (0.05%; one sided 95% confidence interval = 0.08%). CONCLUSIONS/SIGNIFICANCE: The in-depth epidemiological and entomological findings from the Southern Chiapas focus meet the criteria for interruption of transmission developed by the international community.