Full genome and phylogenetic analysis of hepatitis B virus genotype F in Mexican isolates.

Hepatitis B virus genotype F (HBV/F) is endemic in Central and South America with a minor proportion in Mexico and North America. HBV/F is divided into subgenotypes and subtypes with particular geographic circulation patterns. Here, we report the complete genome sequence and molecular characterization of HBV/F from three isolates. Phylogenetic analysis with all available HBV/F sequences showed that our sequences belonged to the F1b subtype and, in addition, the absence of the previously reported F1a subtype in Mexican isolates. Our findings suggest the circulation of HBV/F1b, the first phylogenomic study of HBV/F in Mexico.

Cross-Neutralizing Anti-Chikungunya and Anti-Dengue 2 IgG Antibodies from Patients and BALB/c Mice against Dengue and Chikungunya Viruses.

Dengue (DENV) and Chikungunya (CHIKV) viruses can be transmitted simultaneously by Aedes mosquitoes, and there may be co-infections in humans. However, how the adaptive immune response is modified in the host has yet to be known entirely. In this study, we analyzed the cross-reactivity and neutralizing activity of IgG antibodies against DENV and CHIKV in sera of patients from the Mexican Institute of Social Security in Veracruz, Mexico, collected in 2013 and 2015 and using IgG antibodies of BALB/c mice inoculated with DENV and/or CHIKV. Mice first inoculated with DENV and then with CHIKV produced IgG antibodies that neutralized both viruses. Mice were inoculated with CHIKV, and then with DENV; they had IgG antibodies with more significant anti-CHIKV IgG antibody neutralizing activity. However, the inoculation only with CHIKV resulted in better neutralization of DENV2. In sera obtained from patients in 2013, significant cross-reactivity and low anti-CHIKV IgG antibody neutralizing activity were observed. In CHIKV-positive 2015 sera, the anti-DENV IgG antibody neutralizing activity was high. These results suggest that CHIKV stimulates DENV2-induced memory responses and vice versa. Furthermore, cross-reactivity between the two viruses generated neutralizing antibodies, but exchanging CHIKV for DENV2 generated a better anti-CHIKV neutralizing response.

Nontuberculous mycobacteria in clinical samples with negative acid-fast bacilli.

BACKGROUND: There is a progressive increase in nontuberculous mycobacteria (NTM) in pulmonary and extrapulmonary infections that might cause confusion with the Mycobacterium tuberculosis complex. To determine the frequency of finding NTM in clinical samples from patients diagnosed with active tuberculosis, with negative acid-alcohol-resistant bacilli (acid-fast bacillus [AFB]) in a third-level specialty hospital's mycobacterial laboratory between January 2013 and December 2014. METHODS: This is a prospective, descriptive study where isolated strains of biological material were studied in Lowenstein-Jensen and BACTEC MGIT 960 cultures. RESULTS: Clinical samples of 120 patients were studied, with pulmonary samples of 99/120 (82%) and extrapulmonary samples of 21/120 (18%). We identified NTM in 37/120 samples (30.8%), of which 16 in pulmonary, 13 in genitourinary, 3 in bone marrow, and 5 in various specimens. Mycobacterium avium was isolated in 20 samples, Mycobacterium intracellulare in seven samples, and various other species of NTM in the other 10 samples. CONCLUSION: To establish adequate treatment, we point out the importance of identifying the presence of NTM in the clinical samples of active tuberculosis patients with negative AFB, as possibly becoming confused with M. tuberculosis and which is essential in deciding which treatment is the most adequate.