Molecular biology of Trypanosoma cruzi (Operating since 1992)
- Genotypic variation among lineages of Trypanosoma cruzi detected in feces of Triatoma infestans collected in rural areas subject to entomological surveillance: T.cruzi I and T. cruzi II lineages are routinely evaluated in feces of triatomine bugs, collected in rural areas subject to surveillance. They are evaluated to understand the possible introduction of sylvatic strains of T. cruzi and their possible role in the pathogenesis of Chagas disease.
- Congenital Chagas disease: Routine detection and clinical management of congenital Chagas disease has been improved via the development of new molecular biology tools. A comparison of several diagnostic techniques determined that the polymerase chain reaction (PCR) displayed sensitivity comparable to conventional serology. Furthermore, the Shed Acute Phase Antigen (SAPA) protein, when used in an ELISA system, allowed for unequivocal diagnosis of congenital Chagas disease, thus enabling the identification of infants infected by T. cruzi who were not detected by conventional serology. This technique is actually used in small Health Care Centers at the Public health level. In addition, lineages of T. cruzi I and II have been evaluated in blood samples from congenitally-infected newborns.
Molecular epidemiology, genetic characterization, and evolution of rotavirus and other enteric viruses (Operating since 1998)
- Molecular epidemiology of rotavirus: samples of adults and children under 5 years of age have been analyzed by PAGE and RT-PCR methods for genotyping and nucleotide sequencing. Since 1998, seasonal peaks (from July to September) have been observed in children, whereas in adults levels remain consistent throughout the year. Also, the prevalent genotype may change from season to season, and preliminary results suggest that adults might be the source for genotype variability found in children. Additional studies have led to a detection of high incidence of strains with genotypes not found in anti-rotaviral vaccines.
- Molecular evolution of rotavirus: for this task, sequence data were used from strains circulating in Paraguay or from genebank sequences. By computer analyses, intragenic recombinations were detected (in Argentina) between two sub-lineages of the genotype G4, as was the implication of point mutations and reassortments among different genes (i.e. VP4, VP7, and NSP4) in the genetic diversity of rotavirus isolated in Paraguay. The detection of unusual and emergent genotypes of this virus is under investigation.
- Viral gastroenteritis etiological agent identification: wide knowledge is documented on rotavirus incidence and epidemiology in Paraguay. However, more than 60% of acute diarrhea etiology remains unknown. The aim of this project is to determine the frequency of norovirus, astrovirus, and enteric adenovirus in feces samples of patients with acute diarrhea so that the diagnostic gap can be minimized and a broader overview of the viral acute gastroenteritis burden can be obtained.
Molecular diagnosis and epidemiology of leishmaniasis (Operating since 2002)
In Paraguay, tegumentary leishmaniasis is a very frequent infection detected in rural areas. Untreated cutaneous lesions evolve into the mucosal form because of the metastasis of parasites from the original skin lesions mainly caused by Leishmania (V.) braziliensis. Visceral leishmaniasis is hyperendemic in dogs and is currently becoming a growing public health problem for humans, as it is also caused by Leishmania chagasi in the Americas. In the laboratory, the molecular characterization of Leishmania sp is carried out by molecular methods, that is, specifically, by the PCR technique. Biological samples and isolates are analyzed by PCR-RFLP by amplifying several genes: Hsp70, Mini exon, ITS1 so that the species and the intragenic variation among parasites can be identified. Species identification can aid in the prognosis, as well as in the management of affected patients, and thus prevents the development of the mucosal form of the disease in the tegumentary cases. Currently, the identification of sylvatic reservoirs for tegumentary leishmaniasis and of sandflies vectors of the disease is under investigation.
Molecular Epidemiology of Tuberculosis (Operating since 2002)
The main activities are the diagnosis and molecular epidemiology of Mycobacterium tuberculosis isolates, the identification of resistant strains and atypical mycobacterium.
Molecular tools have been applied to gain knowledge on the transmission of human tuberculosis and settings favoring the dissemination of the disease. The main objective is to determine the genetic diversity and clustering of M. tuberculosis strains circulating in Paraguay. The software BioNumerics (Applied Maths, Belgium) is utilized for the computer-assisted analysis of RFLP patterns. The following techniques are used: DRE-PCR, Spolygotyping, MIRU, SSCP for resistance, and PRA for atypical mycobacterium identification.
Molecular characterization of antibiotic resistance mechanisms (Operating since 2007)
In 2007, the Molecular Biology department established the first scientific network involved in genetic characterization of antibiotic resistant bacterial strains in Paraguay. The network includes microbiology laboratories of the Social Security Main Hospital (IPS) and the School of Medicine Clinical Hospital. Its major goal is to organize a group of cooperating microbiological laboratories with the purpose of applying molecular techniques in the identification of antibiotic resistance genes circulating in Paraguay, and of understanding the epidemiological phenomena of their spread.
Ongoing projects
- Prevalence of Mycoplasma pneumoniae, Chlamydophila pneumoniae, and other bacterial pathogens in patients with community-acquired pneumonia, treated in the Hospital of Respiratory Diseases (INERAM) ‘Juan Max Boettner’.
- Phenotypic and genotypic characterization of extended-spectrum β-lactamases (ESBLs) in clinical isolates of Enterobacteriaceae in the Public Hospitals of Asunción.
- Detection and characterization of β-lactamases (ESBLs) and Metalo β-Lactamases (MBL) in Pseudomonas aeruginosa and Acinetobacter spp.
- Phenotypic and genotypic characterization of Staphylococcus aureus isolated from health workers in Asunción.