Epidemiological surveillance of chikungunya fever in Mexico since its introduction in 2014-2016 and identification of circulating genotypes.

In 2014, the chikungunya virus (CHIKV) was detected for the first time in Mexico, the identified strain was the one corresponding to the Asian genotype which was phylogenetically grouped with the strains that circulated in the British Virgin Islands outbreak and was later classified with lineages of Caribbean strains. In three years, 13,569 cases of chikungunya were registered in Mexico. Although the transmission and spread of the virus are now considered a moderate risk, the danger that the virus reemerges is not ruled out due to the infestation of Aedes mosquitoes. In this study, we reviewed the chikungunya fever (CHIKF) cases reported between 2014 and 2016 to reanalyze the data. Seventeen cases were selected from different states where the circulation of the virus had been reported. Statistical data were analyzed and a retrospective analysis was carried out. Nucleic acid sequences were determined of these 17 samples. 2015 was the year with the highest number of cases (92.8%) and they were detected in 28 states of the country. There is a predominance of females, and the most affected age group was between 25 and 44 years. In 2016, CHIKV genotypes were not known, in this study the presence of the Asian genotype of Caribbean lineage was confirmed. The presence of the West African and ECSA genotypes was phylogenetically ruled out. The sequences obtained were deposited in GeneBank.

Dengue Virus Induces the Release of sCD40L and Changes in Levels of Membranal CD42b and CD40L Molecules in Human Platelets.

Platelets are considered as significant players in innate and adaptive immune responses. The adhesion molecules they express, including P-selectin, CD40L, and CD42b, facilitate interactions with many cellular effectors. Upon interacting with a pathogen, platelets rapidly express and enhance their adhesion molecules, and secrete cytokines and chemokines. A similar phenomenon occurs after exposure of platelets to thrombin, an agonist extensively used for in vitro activation of these cells. It was recently reported that the dengue virus not only interacts with platelets but possibly infects them, which triggers an increased expression of adhesion molecule P-selectin as well as secretion of IL-1ß. In the present study, surface molecules of platelets like CD40L, CD42b, CD62P, and MHC class I were evaluated at 4 h of interaction with dengue virus serotype 2 (DENV-2), finding that DENV-2 induced a sharp rise in the membrane expression of all these molecules. At 2 and 4 h of DENV-2 stimulation of platelets, a significantly greater secretion of soluble CD40L (sCD40L) was found (versus basal levels) as well as cytokines such as GM-CSF, IL-6, IL-8, IL-10, and TNF-α. Compared to basal, DENV-2 elicited more than two-fold increase in these cytokines. Compared to the thrombin-induced response, the level generated by DENV-2 was much higher for GM-CSF, IL-6, and TNF-α. All these events induced by DENV end up in conspicuous morphological changes observed in platelets by confocal microscopy and transmission electron microscopy, very different from those elicited by thrombin in a more physiological scenery.

Overexpression of MMP-3 and uPA with Diminished PAI-1 Related to Metastasis in Ductal Breast Cancer Patients Attending a Public Hospital in Mexico City.

Extracellular matrix metalloproteases and the fibrinolytic system are important protease systems interacting with each other in charge of remodeling and recycling of tissues. Their role in tumor invasion and metastasis is often discussed. In this study several metalloproteases such as MMP-1, MMP-3, MMP-9, and TIMP-1 together with molecules from the fibrinolytic system like uPA, its receptor uPAR, and its inhibitor, PAI-1, were studied by immune-histochemistry to establish a comparison with and without metastasis. From the (118) primary tumors of Mexican patients with ductal breast cancer studied, 56% were grade II and 69% were size T2; the group with metastatic ganglia included 64 samples (54.3%). In patients with metastasis the estimated expression of MMP-3 and uPA (resp., 28% and 45%) was higher than that from no metastatic tumors; it means there is higher expression of both markers in metastatic tumors (p < 0.05). At the same time, metastatic tumors showed statistically significant lower signal of PAI-1 (24%) than tumors without metastasis (p < 0.05). We concluded that overexpression of MMP-3 and uPA, altogether with diminished expression of PAI-1 from metastatic tumors, might be a crucial step towards metastasis in ductal breast cancer. Nevertheless, additional studies in different populations are necessary to establish a pattern.

Macrophage Activation by Ursolic and Oleanolic Acids during Mycobacterial Infection.

Oleanolic (OA) and ursolic acids (UA) are triterpenes that are abundant in vegetables, fruits and medicinal plants. They have been described as active moieties in medicinal plants used for the treatment of tuberculosis. In this study, we analyzed the effects of these triterpenes on macrophages infected in vitro with Mycobacterium tuberculosis (MTB). We evaluated production of nitric oxide (NO), reactive oxygen species (ROS), and cytokines (TNF-α and TGF-ß) as well as expression of cell membrane receptors (TGR5 and CD36) in MTB-infected macrophages following treatment with OA and UA. Triterpenes caused reduced MTB growth in macrophages, stimulated production of NO and ROS in the early phase, stimulated TNF-α, suppressed TGF-ß and caused over-expression of CD36 and TGR5 receptors. Thus, our data suggest immunomodulatory properties of OA and UA on MTB infected macrophages. In conclusion, antimycobacterial effects induced by these triterpenes may be attributable to the conversion of macrophages from stage M2 (alternatively activated) to M1 (classically activated).

Detection of hepatitis C virus coinfection in patients with dengue diagnosis.

Coinfection produced by dengue virus (DENV) and hepatitis C virus (HCV) is a serious problem of public health in Mexico, as they both circulate in tropical zones and may lead to masking or complicating symptoms. In this research, we detected active coinfected patients by HCV residing in the endemic city of Mérida, Yucatán, Mexico, with positive diagnosis to dengue during the acute phase. We performed a retrospective analysis of 240 serum samples from dengue patients. The IgM-ELISA serological test was used for dengue diagnosis, as well as viral isolation to confirm infection. DENV and HCV were detected by RT-PCR. Thus, 31 (12.9%) samples showed DENV-HCV coinfection, but interestingly the highest frequency of coinfection cases was found in male patients presenting hemorrhagic dengue in 19/31 (61.29%), with a predominance of 12 : 7 in males. Firstly, coinfection of DENV-HCV in Mérida, Mexico, was detected in young dengue patients, between 11 and 20 years old (38.7%), followed by those between 21 and 30 years old (32%); only 16.13% were between 0 and 10 years of age. Diagnosis of HCV infection in patients with dengue is highly recommended in order to establish potential risk in clinical manifestations as well as dictate patients' special care.

Detection of hand, foot and mouth disease in the yucatan peninsula of Mexico.

We report a case of hand, foot and mouth disease (HFMD) in a 5-year-old male from Merida City in the Yucatan Peninsula of Mexico. A clinical and physical examination revealed that the patient had symptoms typical of HFMD, including fever, fatigue, odynophagia, throat edema, hyperemia, lesions on the hands and feet, and blisters in the oral cavity. The patient fully recovered after a convalescence period of almost three weeks. Reverse transcription-polymerase chain reaction and nucleotide sequencing revealed that the etiological agent was enterovirus 71 (EV71). The sequence has greatest (90.4%) nucleotide identity to the corresponding regions of EV71 isolates from the Netherlands and Singapore. Although HFMD is presumably common in Mexico, surprisingly there are no data in the PubMed database to support this. This case report provides the first peer-reviewed evidence of HFMD in Mexico.

Dengue virus type 2: protein binding and active replication in human central nervous system cells.

An increased number of dengue cases with neurological complications have been reported in recent years. The lack of reliable animal models for dengue has hindered studies on dengue virus (DENV) pathogenesis and cellular tropism in vivo. We further investigate the tropism of DENV for the human central nervous system (CNS), characterizing DENV interactions with cell surface proteins in human CNS cells by virus overlay protein binding assays (VOPBA) and coimmunoprecipitations. In VOPBA, three membrane proteins (60, 70, and 130 kDa) from the gray matter bound the entire virus particle, whereas only a 70 kDa protein bound in white matter. The coimmunoprecipitation assays revealed three proteins from gray matter consistently binding virus particles, one clearly distinguishable protein (~32 kDa) and two less apparent proteins (100 and 130 kDa). Monoclonal anti-NS3 targeted the virus protein in primary cell cultures of human CNS treated with DENV-2, which also stained positive for NeuH, a neuron-specific marker. Thus, our results indicate (1) that DENV-2 exhibited a direct tropism for human neurons and (2) that human neurons sustain an active DENV replication as was demonstrated by the presence of the NS3 viral antigen in primary cultures of these cells treated with DENV-2.

Ursolic and oleanolic acids as antimicrobial and immunomodulatory compounds for tuberculosis treatment.

BACKGROUND: New alternatives for the treatment of Tuberculosis (TB) are urgently needed and medicinal plants represent a potential option. Chamaedora tepejilote and Lantana hispida are medicinal plants from Mexico and their hexanic extracts have shown antimycobacterial activity. Bioguided investigation of these extracts showed that the active compounds were ursolic acid (UA) and oleanolic acid (OA). METHODS: The activity of UA and OA against Mycobacterium tuberculosis H37Rv, four monoresistant strains, and two drug-resistant clinical isolates were determined by MABA test. The intracellular activity of UA and OA against M. tuberculosis H37Rv and a MDR clinical isolate were evaluated in a macrophage cell line. Finally, the antitubercular activity of UA and OA was tested in BALB/c mice infected with M. tuberculosis H37Rv or a MDR strain, by determining pulmonary bacilli loads, tissue damage by automated histomorphometry, and expression of IFN-γ, TNF-α, and iNOS by quantitative RT-PCR. RESULTS: The in vitro assay showed that the UA/OA mixture has synergistic activity. The intracellular activity of these compounds against M. tuberculosis H37Rv and a MDR clinical isolate in a macrophage cell line showed that both compounds, alone and in combination, were active against intracellular mycobacteria even at low doses. Moreover, when both compounds were used to treat BALB/c mice with TB induced by H37Rv or MDR bacilli, a significant reduction of bacterial loads and pneumonia were observed compared to the control. Interestingly, animals treated with UA and OA showed a higher expression of IFN-γ and TNF-α in their lungs, than control animals. CONCLUSION: UA and OA showed antimicrobial activity plus an immune-stimulatory effect that permitted the control of experimental pulmonary TB.

[Immune responses and immunopathogenesis in infections with dengue virus]. / Respuesta inmune e inmunopatogénesis en las infecciones con el virus del dengue.

We still have an incomplete understanding of both immunoprotection and immunopathogenesis mechanisms in dengue. Proper balance among the components of the immune response plays an important role in protection as well as in pathogenesis because these impact clinical outcomes and severity of dengue cases. In this article, we review the elements of the immune response that participate in DENV infections, and we contrast the levels of immune effectors in both classic dengue fever and the severe dengue fever cases. We also emphasize the components frequently related to the immunopathogenesis in dengue. It is clear that several effectors are increased or dysregulated in the severe cases. Finally, the global mechanism that contributes to the subversion of the immune system in dengue hemorrhagic fever or dengue shock syndrome still requires complete elucidation.

Evaluación de cuatro métodos para la detección de Staphylococcus aureus meticilino-resistente de muestras clínicas en un hospital regional / Evaluation of four methods for detecting methicillin-resistant Staphylococcus aureus isolates from clinical specimens at a regional hospital in Mexico

OBJETIVO: Investigar la prevalencia de Staphylococcus aureus meticilino-resistente (MRSA) en aislados clínicos y determinar la concordancia entre los métodos de detección de MRSA en un laboratorio con recursos y personal limitado. MATERIAL Y MÉTODOS: Se analizaron 140 cepas de Staphylococcus aureus aisladas de muestras clínicas de diferentes departamentos mediante pruebas convencionales: producción de β-lactamasa, sensibilidad a oxacilina con MIC-Vitek 2-XL, ChromID MRSA, difusión en agar para discos de 30 μg de cefoxitina, detección de PBP2a y PCR para el gen mecA. Se determinó el índice kappa de Cohen, para evaluar la concordancia entre los diferentes métodos utilizados. RESULTADOS: La prevalencia encontrada fue de 90.7 por ciento. La sensibilidad y especificidad para los diferentes métodos de detección fue: difusión en disco para cefoxitina 97 y 92 por ciento respectivamente, MIC Vitek 2-XL 97 y 69 por ciento, ChromoID MRSA 97 y 85 por ciento y detección de PBP2a 98 y 100 por ciento. CONCLUSIONES: Todos los métodos son muy buenos para la detección de MRSA; la elección en el uso de cada método dependerá de la infraestructura de cada laboratorio.

OBJETIVE: To estimate the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in clinical isolates and to compare different methods for detection of MRSA in a lab with limited available personnel and resources. MATERIAL AND METHODS: 140 Staphylococcus aureus strains isolated from patients in several departments were assayed for β-lactamase production, MIC-Vitek 2 oxacillin, ChromID MRSA, disk diffusion in agar for cefoxitin 30 μg and PBP2a detection. The results of conventional tests were compared with the "gold standard" PCR test for mecA gene. Cohen´s kappa index was also calculated in order to evaluate the intra assay agreement between the used methods. RESULTS: The found prevalence was 90.7 percent. Sensitivity and specificity were: disk diffusion for cefoxitin 97 and 92 percent respectively, MIC Vitek 2-XL 97 and 69 percent, ChromoID MRSA 97 and 85 percent, and PBP2a detection 98 and 100 percent. CONCLUSIONS: All methods are very good for detecting MRSA, choosing a method to use will depend on each laboratory infrastructure.

[Evaluation of four methods for detecting methicillin-resistant Staphylococcus aureus isolates from clinical specimens at a regional hospital in Mexico]. / Evaluación de cuatro métodos para la detección de Staphylococcus aureus meticilino-resistente de muestras clínicas en un hospital regional.

OBJECTIVE: To estimate the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in clinical isolates and to compare different methods for detection of MRSA in a lab with limited available personnel and resources. MATERIAL AND METHODS: 140 Staphylococcus aureus strains isolated from patients in several departments were assayed for ß-lactamase production, MIC-Vitek 2 oxacillin, ChromID MRSA, disk diffusion in agar for cefoxitin 30 µg and PBP2a detection. The results of conventional tests were compared with the "gold standard" PCR test for mecA gene. Cohen´s kappa index was also calculated in order to evaluate the intra assay agreement between the used methods. RESULTS: The found prevalence was 90.7%. Sensitivity and specificity were: disk diffusion for cefoxitin 97 and 92% respectively, MIC Vitek 2-XL 97 and 69%, ChromoID MRSA 97 and 85%, and PBP2a detection 98 and 100%. CONCLUSIONS: All methods are very good for detecting MRSA, choosing a method to use will depend on each laboratory infrastructure.

[The origin of the genetic variability of influenza viruses]. / El origen de la variabilidad genética de los virus de la influenza.

To better understand the significant variability displayed by influenza viruses, we need to be aware not only of its genetic characteristics, but also of the effect this genetic makeup has on proteins associated with viral replication and antigenicity. The origin of such diversity is due first and foremost to its segmented genome that allows segment reassortment (antigenic shift) and second to the error prone viral polymerase (antigenic drift) responsible of copying the genes enclosed in these segments. These two combined mechanisms confer a genetic plasticity that often leads to the emergence of new influenza viruses in nature.