Characterization of the genetic diversity of extensively-drug resistant Mycobacterium tuberculosis clinical isolates from pulmonary tuberculosis patients in Peru.

BACKGROUND: Peru holds the fourth highest burden of tuberculosis in the Americas. Despite an apparently well-functioning DOTS control program, the prevalence of multidrug resistant tuberculosis (MDR-TB) continues to increase. To worsen this situation, cases of extensively drug resistance tuberculosis (XDR-TB) have been detected. Little information exists about the genetic diversity of drug-susceptible vs. MDR-TB and XDR-TB. METHODS: Cryopreserved samples of XDR strains from 2007 to 2009 (second semester), were identified and collected. Starting from 227 frozen samples, a total of 142 XDR-TB strains of Mycobacterium tuberculosis complex (MTBC; 1 isolate per patient) were retained for this study. Each strain DNA was analyzed by spoligotyping and the 15-loci Mycobacterial Interspersed Repetitive Unit (MIRU-15). RESULTS: Among the 142 isolates analyzed, only 2 samples (1.41%) could not be matched to any lineage. The most prevalent sublineage was Haarlem (43.66%), followed by T (27.46%), LAM (16.2%), Beijing (9.15%), and X clade (1.41%). Spoligotype analysis identified clustering for 128/142 (90.1%) isolates vs. 49/142 (34.5%) with MIRUs. Of the samples, 90.85% belonged to retreated patients. The drug resistant profile demonstrated that 62.67% showed resistance to injectable drugs capreomycin (CAP) and kanamycin (KAN) vs. 15.5% to CAP alone and 21.8% to KAN alone. The SIT219/T1 and SIT50/H3 were the most prevalent patterns in our study. The spoligoforest analysis showed that SIT53/T1 was at the origin of many of the T lineage strains as well as a big proportion of Haarlem lineage strains (SIT50/H3, followed by SIT47/H1, SIT49/H3, and SIT2375/H1), as opposed to the SIT1/Beijing strains that did not appear to evolve into minor Beijing sublineages among the XDR-TB strains. CONCLUSION: In contrast with other Latin-American countries where LAM sublineage is the most predominant, we found the Haarlem to be the most common followed by T sublineage among the XDR-TB strains.

Temporal differences in blood meal detection from the midguts of Triatoma infestans.

We used genus/species specific PCRs to determine the temporal persistence of host DNA in Triatoma infestans experimentally fed on blood from six common vertebrate species: humans, domestic dogs, guinea pigs, chickens, mice, and pigs. Twenty third or fourth instar nymphs per animal group were allowed to feed to engorgement, followed by fasting-maintenance in the insectary. At 7, 14, 21, or 28 days post-feeding, the midgut contents from five triatomines per group were tested with the respective PCR assay. DNA from all vertebrate species was detected in at least four of five study nymphs at seven and 14 days post-feeding. DNA of humans, domestic dogs, guinea pigs, pigs, and chickens were more successfully detected (80-100%) through day 21, and less successfully (20-100%) at day 28. Findings demonstrate that species-specific PCRs can consistently identify feeding sources of T. infestans within two weeks, a biologically relevant time interval.

Temporal differences in blood meal detection from the midguts of Triatoma infestans / Diferencias temporales en la detección de fuentes de alimentación en el contenido intestinal de Triatoma infestans

We used genus/species specific PCRs to determine the temporal persistence of host DNA in Triatoma infestans experimentally fed on blood from six common vertebrate species: humans, domestic dogs, guinea pigs, chickens, mice, and pigs. Twenty third or fourth instar nymphs per animal group were allowed to feed to engorgement, followed by fasting-maintenance in the insectary. At 7, 14, 21, or 28 days post-feeding, the midgut contents from five triatomines per group were tested with the respective PCR assay. DNA from all vertebrate species was detected in at least four of five study nymphs at seven and 14 days post-feeding. DNA of humans, domestic dogs, guinea pigs, pigs, and chickens were more successfully detected (80-100%) through day 21, and less successfully (20-100%) at day 28. Findings demonstrate that species-specific PCRs can consistently identify feeding sources of T. infestans within two weeks, a biologically relevant time interval.

Se utilizó pruebas PCR género o especie específicas para determinar la persistencia temporal de ADN del hospedero en el contenido intestinal de Triatoma infestans que fueron alimentados experimentalmente con sangre de seis vertebrados muy frecuentemente asociados a enfermedad de Chagas: humano, perro, cobayo, pollo, ratón, y cerdo. Se emplearon 20 ninfas de tercer y cuarto estadio por cada especie de hospedero. Fueron alimentados a saciedad y mantenidas en el insectario sin alimentación posterior. Se obtuvo el contenido intestinal de cinco triatominos por cada grupo a los 7, 14, 21 y 28 días post - alimentación, que fueron evaluados con los respectivos PCRs específicos. El ADN de todos los vertebrados fue detectado en al menos 4 de 5 ninfas evaluadas a los 7 y 14 días post - alimentación. El ADN de humano, perro, cobayo, cerdo y pollo fue detectado exitosamente (80-100%) hasta el día 21 y con menos éxito (20-100%) en el día 28. Estos resultados demuestran que PCRs específicos para cada especie de hospedero pueden identificar consistentemente la fuente de alimentación de T. infestans dentro de las dos semanas post - alimentación, siendo un intervalo de tiempo biológicamente relevante.

Retardo de crecimiento intrauterino, factores de riesgo / Intra-uterine growth retard, risk factos

Se presenta un estudio de la incidencia de retardo de crecimiento intrauterino sobre un total de 4.422 pacientes atendidos en el Hospital San Roque entre 1/01/94 y 30/09/96, encontrándose valores estadíssticos concordantes con los publicados previamente en la estadística básica del Sistema Informativo Perinatal (SIP)