Liana Lauria-Pires

Polymorphisms in Trypanosoma cruzi: evidence of genetic recombination

The ploidy of Trypanosoma cruzi is until now undetermined although analysis of isoenzymes, molecular karyotype and DNA content suggest diploidy in a very plastic genome. Also, there has been no convincing demonstration of genetic exchange and it has been proposed that reproduction is clonal. We have compared 18 T cruzi stocks and clones from the same area or host by means of isoenzyme analysis (12 loci) and restriction site polymorphisms in and around three glycolytic genes (glyceraldehyde-3-phosphate dehydrogenase, aldolase and glucosephosphate isomerase). The analysis demonstrated the presence of homozygotes and heterozygotes and is compatible with diploidy for these housekeeping genes. This strongly supports the hypothesis of genetic exchange in T cruzi and further elucidates the genetic diversity within natural T cruzi populations.

Heritable Integration of kDNA Minicircle Sequences from Trypanosoma cruzi into the Avian Genome: Insights into Human Chagas Disease

We demonstrate the genetic transfer of DNA between eukaryotes from different kingdoms. The mitochondrial kinetoplast DNA (kDNA) of the intracellular parasite Trypanosoma cruzi is transferred to human patients with Chagas disease. This transfer was reproduced experimentally in rabbits and chickens. The kDNA is integrated into the host genome. In the human chromosomes, five loci were identified as integration sites, and the beta-globin locus and LINE-1 retrotransposons were frequently targeted. Short repeated sequences in the parasite and the target host DNAs favor kDNA integration by homologous recombination. Introduced kDNA was present in offspring of chronically infected rabbits and in chickens hatched from T. cruzi-inoculated eggs. kDNA incorporated into the chicken germline was inherited through the F2 generation in the absence of persistent infection. kDNA integration represents a potential cause for the autoimmune response that develops in a percentage of chronic Chagas patients, which can now be approached experimentally.

Diversity of Trypanosoma cruzi stocks and clones derived from Chagas disease patients: I-Behavioral characterization in vitro

In this study, we isolated Trypanosoma cruzi from chronic Chagas heart disease and from megaesophagus patients. The parasite stock hSLU239 (heart disease) yielded clones h1 and h2, whereas stock mSEU142 (megaesophagus) yielded clones m1, m2, m3 and m4. The parasite growth kinetics, doubling time and differentiation in axenic liquid medium showed broad behavioral diversity. It was shown that a particular pattern of behavior for a parental stock could not necessarily be assigned for subsequent clones. This study indicates that i) each Chagas disease patient is infected with several T. cruzi populations; ii) clonal lines derived from patient samples may have different biological characteristics from the original isolate; and that iii) additional behavioral and/or molecular markers are required for further characterization of Trypanosoma cruzi stocks and clones derived from Chagas disease patients in order to identify correlations with pathology.

Exposure to mixed asymptomatic infections with Trypanosoma cruzi, Leishmania braziliensis and Leishmania chagasi in the human population of the greater Amazon

Lack of conservation of the Amazon tropical rainforest has imposed severe threats to its human population living in newly settled villages, resulting in outbreaks of some infectious diseases. We conducted a seroepidemiological survey of 1100 inhabitants of 15 villages of Paço do Lumiar County, Brazil. Thirty‐five (3%) individuals had been exposed to Trypanosoma cruzi (Tc), 41 (4%) to Leishmania braziliensis (Lb) and 50 (4.5%) to Leishmania chagasi (Lc) infections. Also, 35 cases had antibodies that were cross‐reactive against the heterologous kinetoplastid antigens. Amongst these, the Western blot assays revealed that 11 (1%) had Tc and Lb, that seven (0.6%) had Lc and Tc, and that 17 (1.6%) had Lb and Lc infections. All of these cases of exposures to mixed infections with Leishmania sp, and eight of 11 cases of Tc and Lb were confirmed by specific PCR assays and Southern hybridizations. Two cases had triple infections. We consider these asymptomatic cases showing phenotype and genotype markers consistent with mixed infections by two or more kinetoplastid flagellates a high risk factor for association with Psychodidae and Triatominae vectors blood feeding and transmitting these protozoa infections. This is the first publication showing human exposure to mixed asymptomatic kinetoplastid infections in the Amazon.

Use of antibacterial agents in an intensive care unit in a hospital in Brazil

It is essential to monitor the utilisation of antibacterial drugs in order to establish appropriate measures for their control. The pattern of usage of antibacterial drugs, and its association with indicators of hospital infection, has been investigated in a non-specialized adult intensive care unit (ICU) located in Santa Luzia Hospital (Brasília, DF, Brazil). The study was conducted between January 2001 and June 2004. Data concerning the utilisation of systemic antibacterial drugs, classified according to the Anatomical Therapeutic Chemical/Defined Daily Dose (ATC/DDD) system, and indicators of hospital infection, defined according to the National Nosocomial Infections Surveillance (NNIS) system, were obtained from appropriate hospital archives. During the study period, the average utilisation of antibacterial drugs was 1918.5 DDD units per 1000 patient-day (DDD(1000)). The three most used drugs were penicillins/beta-lactamase inhibitors (535.3 DDD(1000)), third generation cephalosporins (239.1 DDD(1000)) and quinolones (212.5 DDD(1000)). The total utilisation of antibacterial drugs was correlated significantly with the incidence of hospital infection (R = 0.62; p < 0.01) and the index of invasive procedures (R = 0.41; p < 0.01). Furthermore, the latter two indicators were significantly and positively correlated with the use of recently commercialized, broad spectrum antibacterial drugs (except for carbapenems). It is concluded that improved infection control procedures, together with more rigorous criteria regarding the use of invasive procedures, should be implemented by the ICU studied in order to diminish the utilisation of antibacterial drugs.

Padrões de utilização de antibacterianos em unidades de terapia intensiva

OBJETIVO: conhecer e comparar os padroes de consumo de antibacterianos em unidades de terapia intensiva com base no sistema Anatomical Therapeutic Chemical/Defined Daily Dose (ATC/DDD). METODOS: estudo de coorte, prospectivo, realizado em tres unidades de terapia intensiva medico-cirurgicas, duas localizadas em dois hospitais publicos e uma em hospital privado. Amostras aleatorias simples, independentes, dos pacientes internados nas unidades de terapia intensiva no periodo de 10/2004 a 09/2005 foram utilizadas. O consumo de antibacterianos foi avaliado com o sistema ATC/DDD. A quantidade utilizada de antibacteriano nas unidades de terapia intensiva, em gramas, foi transformada em dose diaria definida (DDD). O numero de DDD foi dividido pelo numero de pacientes-dia e multiplicado por mil, compondo a densidade media de consumo por mil pacientes-dia (DDD1000). RESULTADOS: Hum mil setecentos e vinte e oito (1.728) pacientes-dia e 2.918,6 DDD foram analisados nas tres unidades de terapia intensiva, correspondendo a densidade media de consumo de 1.689,0 DDD1000. A mediana do numero de DDD referente a utilizacao de antibacterianos nas unidades de terapia intensiva dos hospitais publicos foi significativamente maior (p=0,002) do que na unidade de terapia intensiva do hospital privado. Ao contrario, a densidade de consumo de antibacterianos na unidade de terapia intensiva do hospital privado (2.191,7DDD1000) foi significativamente maior (p<0,001) do que nas unidades de terapia intensiva dos hospitais publicos (1.499,5DDD1000). Os grupos de antibacterianos mais utilizados nas tres unidades de terapia intensiva foram cefalosporinas de 3a geracao, penicilinas/inibidores de betalactamases, carbapenemicos e fluorquinolonas. CONCLUSAO: os padroes de consumo de antibacterianos nas tres unidades de terapia intensiva analisadas nao foram uniformes. A unidade de terapia intensiva do hospital privado utilizou quantidade significativamente maior, em termos de densidade de consumo, do que as unidades de terapia intensiva dos hospitais publicos. Apesar disso, os grupos de antibacterianos mais utilizados nas tres unidades de terapia intensiva foram semelhantes.

Emprego de quatro exames imunológicos na determinaçäo da prevalência da doença de Chagas nos garis do Serviço de Limpeza Urbana do Distrito Federal

Seropositivity for Trypanosoma cruzi infection was studied in 308 street-sweepers of the SLU. Federal District. Brazil, with the aid of haemaglutination. immunofluorescence and, also, a delayed-type skin test to the parasite T12E antigen. It showed 32,1%, 42.7% and 38.6% positive results, respectively for cach assay. Among these, however, only 47% were positive with each of three exams performed. In addition, 19.7% were positive with two out of three exams performed. The remaining 33-3% sera yielded one positive result out of three exams employed and were submitted to the immunoblot assay. This analysis confirmed 3 cases (37.5%) positive by hemmaglutination. 3 (11.5%) positive by skin test, and 1 (3-7%) positive by immunofluorescence. At the end of the analysis, it was shown that 129 (35%) individuals yielded at least two positive assays and therefore, they should be cousidered as T. cruzi-infected individuals.