[Identification of Mycobacterium avium-intracellulare complex by PCR of AIDS and disseminated mycobacteriosis]. / Identificación del complejo Mycobacterium avium-intracellulare por PCR en SIDA y micobacteriosis diseminada.

OBJECTIVE: The aim of this study is to differentially identify MAC by PCR in patients with AIDS and disseminated mycobacteriosis. METHODS: A cross sectional study was conducted in Mexico to identify MAC by Molecular Biology. Two sets of primers were synthesized: MAV and MIN, for M. avium and M. intracellulare, respectively. Whole-cell DNAs obtained from 29 clinical isolates and clinical serum specimens from other 24 patients with AIDS and disseminated mycobacterial infection were extracted and amplified by PCR with the MAV and MIN primers. The MAV and MIN primers each amplified one highly specific 1.3-kb segment of the homologous DNA, respectively. RESULTS: Twenty-nine DNAs from MAC clinical isolates identified by Gen-Probe AccuProbes were amplified with the MAV primers. Of the 24 clinical samples, 3 were positive for M. avium and 6 for M. tuberculosis. CONCLUSIONS: Our results demonstrated that PCR technique could be applied for the differentiation of M. avium and M. intracellulare by specific 16S rRNA primers. In patients with advanced stage AIDS and in whom disseminated mycobacteriosis is suspected, the presence of anemia (even with negative cultures), elevated alkaline phosphatase and a median CD4 count of 15.9/mL, the diagnosis of infection by MAC should be strongly considered; we suggest that in accordance with our findings, a more precise stratification of patients in terms of their CD4 T cell counts is warranted.

Introducción: el objetivo de este artículo es Identificar y diferenciar el complejo MAC por PCR en pacientes con SIDA y micobacteriosis diseminada. Métodos: se llevó a cabo un estudio transversal para identificar MAC por biología molecular. Se sintetizaron dos conjuntos de iniciadores: MAV y MIN, para M. avium y M. intracellulare, respectivamente. El ADN total de células obtenidas de 29 aislados clínicos y muestras de suero de otros 24 pacientes con SIDA e infección micobacteriana diseminada fue extraído y se amplificó por PCR con los iniciadores MAV y MIN. Cada uno de los iniciadores MAV y MIN amplificó un segmento altamente específico de 1.3 kb del ADN homólogo, respectivamente. Resultados: veintinueve ADN de los aislados clínicos de MAC identificadas por Gen-Probe AccuProbes se amplificaron con los iniciadores MAV (M. avium). De las 24 muestras clínicas, 3 fueron positivas para M. avium y 6 para M. tuberculosis. Conclusiones: nuestros resultados demostraron que la técnica de PCR se puede aplicar para la diferenciación de M. avium y M. intracellulare por iniciadores específicos 16S rRNA. En pacientes con estadio avanzado de SIDA y en quienes se sospecha micobacteriosis diseminada, la presencia de anemia (incluso con cultivos negativos) fosfatasa alcalina elevada y una mediana de CD4 de 15.9/ml, se debe considerar seriamente el diagnóstico de infección por MAC; sugerimos que, de acuerdo con nuestros resultados, se justifica una estratificación más precisa de los pacientes en términos de sus recuentos de células T CD4.

[Microbiology of bronchoalveolar lavage in infants with bacterial community-acquired pneumonia with poor outcome]. / Microbiología de lavado broncoalveolar en lactantes con neumonía bacteriana adquirida en la comunidad de mala evolución.

BACKGROUND: Community-acquired pneumonia (CAP) is one of the most common infectious causes of morbidity and mortality in children <5 years of age. The aim of the study was to clarify the bacterial etiologic diagnosis in infants with CAP. METHODS: A prospective, cross-sectional and descriptive study in patients 6 months to 2 years 11 months of age with CAP with poor outcome was conducted. Patients were admitted to the Pediatric Pneumology Service and underwent bronchoscopy with bronchoalveolar lavage (BAL), taking appropriate measures during the procedure to limit the risk of contamination. RESULTS: Aerobic bacteria isolated were Moraxella sp. 23%, Streptococcus mitis 23%, Streptococcus pneumoniae 18%, Haemophilus influenzae 12%, Streptococcus oralis 12%, and Streptococcus salivarius 12%. CONCLUSIONS: In contrast to other reports, we found Moraxella sp. to be a major bacterial pathogen, possibly because of improved detection with bronchoscopy plus BAL.

Clinical, radiological and molecular diagnosis correlation in serum samples from patients with osteoarticular tuberculosis.

OBJECTIVE: To assess the role of polymerase chain reaction (PCR) in serum samples, in the diagnosis of osteoarticular tuberculosis (OTB) in a setting where only clinical and imaging diagnoses determine the treatment. METHODS: A total of 44 consecutive serum specimens were collected from clinically suspected OTB patients, based on clinical and radiological [X-ray or magnetic resonance imaging/computed tomography] features. They were screened by in-house nested PCR. In addition, a few specimens were examined by Gram stain, acid-fast bacilli stain, histopathology and routine bacterial culture. A total of 39 specimens were collected from patients suffering from other bone diseases of nontuberculous origin and included as negative controls. RESULTS: Of the 44 clinically suspected OTB patients, in-house nested PCR was positive in 40 (91%) cases; PCR was negative in 38 (97%) negative controls. Sensitivity and specificity of our in-house nested PCR was 90.9% and 97.4%, respectively. The PCR report was available within 48 h. It was possible to standardize serum PCR technique and in positive cases, a good correlation was observed in terms of an adequate treatment response. CONCLUSIONS: Nested PCR in serum samples is a rapid, highly sensitive and specific modality for OTB detection. PCR should be performed in addition to clinical evaluation, imaging studies, acid-fast bacilli staining, culture and histopathology diagnosis, if possible.

[Opportunistic bacteria and microbial flora in children with leukemia and neutropenic enterocolitis]. / Bacterias oportunistas y microbiota en niños con leucemia y enterocolitis neutropénica.

OBJECTIVE: to determine the prevalence of opportunistic microorganisms and microbial flora in neutropenic enterocolitis in oncohematological pediatric patients. METHODS: a prospective and observational study was done. Patients with diagnosis of acute leukemia and neutropenia were included. Stool cultures were taken to identify microorganisms and microbial flora. A χ(2) test with Yates corrections and Fisher exact test were used in the statistical analysis. RESULTS: 21 patients were included (12 male, 57.1 %). The stool cultures showed that 68 % of microorganisms were Gram-negative. The presence of microorganisms Gram-positive was 20 %, 6 % for Candida sp.; 3 % for Cryptosporidium sp.; and in 3 % were acid fast bacilli. Staphylococcus epidermidis, Enterobacter sp., and Escherichia coli were presented in pure culture. No association was found between Gram-positive and Gram-negative microorganisms with age, white cell count or pure or mixed cultures. CONCLUSIONS: although Gram-negative microorganisms were the most frequent, Gram-positive and other microorganisms that are not detected habitually in feces culture were isolated.

Objetivo: determinar la microbiota y la prevalencia de microorganismos oportunistas en niños con leucemia y enterocolitis neutropénica. Métodos: se realizó un estudio prospectivo observacional en pacientes con leucemia aguda y neutropenia. Se tomaron cultivos de heces para identificar la presencia de bacterias y microbiota. Se aplicó estadística descriptiva para su análisis. Resultados: fueron incluidos 21 pacientes (12 hombres, 57.1 %). En 68 % de los coprocultivos se observó desarrollo de microorganismos gramnegativos. La presencia de microorganismos grampositivos fue de 20 %, 6 % de Candida sp., 3 % de Cryptosporidium sp. y en 3 % se observaron bacilos ácido alcohol resistentes. Staphylococcus epidermidis, Enterobacter sp., y Escherichia coli se observaron en cultivo puro. No se encontró asociación entre microorganismos grampositivos y gramnegativos con la edad, el recuento leucocitario ni el cultivo puro o mixto.Conclusiones: aunque los microorganismos gramnegativos fueron los más frecuentes, se aislaron de manera importante grampositivos y otros que no se buscan de rutina en el coprocultivo.

-592 and -1082 interleukin-10 polymorphisms in pulmonary tuberculosis with type 2 diabetes.

OBJECTIVE: To determine the polymorphisms of Interleukin-10 (IL-10) (-592, -1082) in pulmonary tuberculosis (PTB) with and without type 2 diabetes (T2D). METHODS: We studied a Mexican mestizo population of 37 patients with TB in remission (TBr) and 40 with active pulmonary TB (PTB), 21 patients with TB + T2D, 47 blood donors accepted, and 13 healthy health-care workers with tuberculin skin test positive. Determination of IL-10 polymorphisms was performed by real-time Polymerase chain reaction. RESULTS: IL-10-592C/A presented in a greater proportion in healthy individuals than in patients with type 2 diabetes and TB in a not quite significant statistically manner. IL-10-1082A/A presented more frequently in the group of patients with both diseases, not being statistically significant in comparison with the group of healthy subjects. CONCLUSIONS: This study describes two important new findings. First, it reveals that the IL-10 (-592 A/A and -592 C/C) polymorphisms were found in a greater proportion in a group of patients with T2D and TB than in healthy subjects. Second, the study provides evidence that the (-1082 G/G) polymorphism presented with greater frequency in healthy individuals than in patients with both of these diseases.

Genetic polymorphisms of the tumor necrosis factor and lymphotoxin alpha in type 2 diabetes.

OBJECTIVE: To investigate the frequency of the single-base change polymorphic variants identified in tumor necrosis factor (TNF) gene (-308 G/A) and lymphotoxin alpha (LTA) (+252 G/A) in patients with type 2 diabetes (T2D). METHODS: A prospective study in a Mexican-mestizo population of 51 patients with T2D and 48 healthy subjects was carried out. We took a peripheral blood sample from each individual for identification of the polymorphic genotypes by polymerase chain reaction. RESULTS: The genotype distribution in T2D was: TNF alpha homozygous 0%; TNFG/A heterozygous 20%; TNFG homozygous 80%. CONCLUSIONS: In regards to the TNF -308 G/A genotype, we found a significant difference (p = 0.012) with a bigger frequency in the group of patients. The health controls showed a higher frequency of TNF -308 G/G genotype (p = 0.034).

Interferon γ in patients with HIV/AIDS and suspicion or latent tuberculosis infection.

OBJECTIVE: To assess the usefulness of IGRA test (QuantiFERON(®)-Cell mediated immune) compared with the tuberculin skin test. METHODS: A cross-sectional study was carried out in Mexico, 25 infected patients with HIV-AIDS and the suspicion or with latent tuberculous infection (LTBI) who were >18 years of age and without treatment for tuberculosis (TB), were enrolled in the study. RESULTS: Median cluster of differentiation (CD4) count was 364 cells/µ L and median HIV viral load was 50 copies/mL. Overall, 20 patients (80%) had at least one positive diagnostic test for LTBI: four (16%) had a positive tuberculin skin test and 19 (76%), a positive QuantiFERON(®)-tuberculosis. CONCLUSIONS: No agreement is found between the two diagnostic tests: k = -0.004, 95% confidence interval (-0.2219, 0.2210). Additional longitudinal studies among HIV-infected populations with high prevalence of TB are needed to further assess the usefulness of IGRAs in this patient population.

[Pro-inflammatory cytokines related to severity and mortality in type 2 diabetes patients with soft tissue infection]. / Citocinas, diabetes e infección de tejidos blandos. Su relación con la severidad y mortalidad.

OBJECTIVE: to determine the relation between IL6, IL10 and TNFa serum levels in a cohort of patients with type 2 diabetes (T2D) and severe soft tissue infections (STI), with severity and mortality factors. METHODS: A. comparative and transversal, study with 15 adult patients, any gender, with T2D and STI were done. A T2D control group of 20 patients without STI was included. Apache II Score, glycemia and by ELISA, IL6, IL10 and TNFa, were determined. RESULTS: in all patients, it was a correlation at beginning between glycemia and IL6 (r = 0.67, IC 95 % 0.24-0.88), as soon as glycemia and Apache II, (r = 0.59, IC 95 % 0.11-0.83). CONCLUSIONS: although IL6 was very usefulness, it is not a routine test in clinical laboratory and it is expensive, but in medical practice, it could be possible to evaluate these patients with Apache II Score and glycemia. However, in STI, the values of IL6 and IL10 were highly significant. It is likely that IL6 is a marker of poor outcome.

The usefulness of the buffy coat smear and panbacterial polymerase chain reaction in early diagnosis of neonatal sepsis.

OBJECTIVE: In this study are evaluated the usefulness of the buffy coat smear and panbacterial polymerase chain reaction (PCR) as diagnostic tests in the early detection of neonatal sepsis. MATERIAL AND METHODS: It was studied 49 patients aged up to 28 days who were hospitalized in the Intensive Care Unit (ICUs) of the Neonatology, with a clinical diagnosis of neonatal sepsis and 49 umbilical cord samples of healthy newborns. Blood cultures and 50 microL of plasma were taken for the DNA and performance of the broad-range PCR primer system (panbacterial PCR). Simultaneously, were taken three capillaries with blood for the leukocyte layer (buffy coat) smear, we performed three stains: Gram; Löeffler blue methylene (LBM), and acridine orange (AO). Statistical analysis included sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) against the clinical diagnosis. RESULTS: With respect to stains of buffy coat smear, they resulted very specific, from 90-97%, with 64-75% sensitivity, 87-94% PPV, and 77-82% NPV. In inverse fashion, PCR resulted very sensitive at 96%, with 91% specificity, 92% PPV, and 96% NPV. CONCLUSIONS: Buffy coat smear stains are easy, fast, and specific, while that of PCR was highly sensitive. Thus, both can be utilized as diagnostic tests.

[CSF RT-PCR standardization in pediatric patients with enteroviral central nervous system infection]. / Estandarización de RT-PCR en LCR de pacientes pediátricos con infección del sistema nervioso central por enterovirus.

OBJECTIVE: We standardized the RT-PCR panviral CSF and determined its applicability in detecting acute enterovirus infection in the central nervous system in children under 15 years. MATERIAL AND METHODS: RT-PCR was performed directly in CSF samples of 10 pediatric patients with suspected CNS infection and 9, with different conditions of the central nervous system. RESULTS: 80% (8/10) of RT-PCR samples were positive for enterovirus in patients with suspected CNS infection and no sample was positive in patients with different ailments. CONCLUSIONS: Since enteroviruses are among the main etiologies of pediatric encephalitis, RT-PCR could be particularly useful for rapid detection in CSF.

Functional state analysis of phagocytic cells of patients with type 2 diabetes and pulmonary tuberculosis.

BACKGROUND: The phagocytic function in pulmonary tuberculosis (PTB) and Type 2 diabetes (T2D) has been explored mainly in macrophages but not in polymorphonuclears (PMN). The purpose of this study was to determine the functional status of PMN leukocytes in patients with pulmonary tuberculosis (PTB), Type 2 diabetes (T2D), and in patients with both diseases. METHODS: An observational, prospective, and comparative study was carried out. 30 ambulatory patients with T2D, 10 with PTB undergoing treatment and 10 patients with PTB and T2D, and 44 healthy subjects were studied. PMN leukocytes were separated, the capacity of these cells to produce hydrogen peroxide and to reduce nitroblue tetrazolium (NBT) in response to stimulus with the phorbolic ester of myristic acid (PMA) was measured; and the capacity of PMN leukocytes to adhere to surfaces was determined. RESULTS: Concerning the test for adherence, on comparing healthy subjects with patients with T2D+PTB, we observed a clear decrease in cellular adherence in the group of patients with both diseases; it was statistically significant (p = 0.007).With regard to phagocytic function, we observed that in NBT reduction as well as in hydrogen peroxide production, statistically significant differences were not obtained on comparing healthy subjects with any of the three groups of patients. CONCLUSIONS: We observed a clear decrease in cellular adherence when both diseases co-exist. These results could indicate the need for the co-existence of T2D and TB to cause deterioration in the cells' adherence activity. The microtechniques employed permit the evaluation in a practical manner of certain phagocytic-activity expressions.

Tumor necrosis factor -308 and lymphotoxin +252 polymorphisms in Mexican children with Kawasaki disease and coronary aneurysms.

BACKGROUND AND AIMS: The Mexican population has a distinct capacity for the expression of tumor necrosis factor (TNF), a cytokine that plays a cardinal role in Kawasaki disease (KD), particularly in those who develop coronary aneurysms. It is important to identify, in Mexican pediatric patients, the association of the frequency of TNF. This study determined the association of TNF -308 and lymphotoxin-alpha (LTA) +252 polymorphisms in Mexican pediatric patients with KD and coronary aneurysms (CA). METHODS: We conducted a cross-sectional, analytical study in 48 children with KD, 22 with CA. Control samples were obtained from 61 aged-matched children. We took a peripheral blood sample and extracted genomic DNA from all children participating in the study. Using restriction factor length polymorphism-polymerase chain reaction (RFLP-PCR), we performed determination of TNF -308 and LTA +252. RESULTS: There was no difference in frequency between the study groups for genotype LTA +252 (OR 0.37, 95% CI, 0.06-2, p = 0.44) or between groups for KD with or without coronary aneurysms for both polymorphisms. In subjects with KD, we did not observe the heterozygous genotype of TNF -308, the difference being significant (OR 12, 95% CI, 4.8-30.4, p = 0.0001) using the χ(2) test with the continuity correction on comparison with the control group. CONCLUSIONS: Comparative analysis by group did not show a significant difference in the frequency of the alleles and genotypes between KD with CA vs. KD without CA vs. controls, for both TNF -308 and LTA +252.

Anti-chlamydophila pneumoniae antibodies as associated factor for carotid atherosclerosis in patients with AIDS.

Atherosclerosis is a multifactor disease. Lately, infectious factors such as C. pneumoniae have been found to be involved. To determine whether the infection by C. pneumoniae is a risk factor for atherosclerosis in patients with AIDS. Case-control study on 43 patients with AIDS under HAART (16 cases and 27 controls). To document atherosclerosis, a carotid and transcranial Doppler ultrasound was performed. Anti-C pneumoniae antibodies were searched using a microimmunofluorescence test for IgM and IgG levels. To study the associations with risk of atherosclerosis, Odds Ratios were calculated for each IgG anti-C. pneumoniae antibody titre. A titre of 1:64 significantly increased the risk of atherosclerosis. These results suggest that hypertriglyceridemia and C. pneumoniae infection coexistence significantly increases the risk of atherosclerosis. The inverse geometric average of the antibodies titre against C. pneumoniae in individuals with atheromatous plaque fell to 64, two titres above the controls. This difference turned out to be statistically significant. Exposure to C. pneumoniae with antibodies (IgG) should be considered in any HIV diagnosed patient as a risk factor for atherosclerosis, having found that the inverse geometric averages of antibodies titre are significantly different comparing cases and controls, especially in patients with dyslipidemia, hypertriglyceridemia or in patients whose treatments could cause these conditions. In patients with concomitant hypertriglyceridemia, the association increases up to three times. It is advisable that AIDS patients take a serological test to determine exposure to C. pneumoniae, and to assess treatment options.

Detection of Mycobacterium tuberculosis from respiratory samples with the liquid culture system MB/BacT and verified by PCR.

OBJECTIVE: To assess the performance in the clinical setting of the MB/BacT system for isolation of Mycobacterium tuberculosis and to verify by PCR. MATERIAL AND METHODS: The study included 272 sputum samples from 208 patients with the presumptive diagnosis of pulmonary tuberculosis. ZN was made, culture in Löwenstein-Jensen medium, MB/BacT and PCR. RESULTS: Thirty-nine samples were positive by culture in Löwenstein-Jensen, and 42 using the MB/BacT system. Positive cultures in the MB/BacT system were verified by acid-fast bacilli staining and PCR. Mycobacterial identification in the MB/BacT took 8 to 46 days (mean 16 days), while the Löwenstein-Jensen culture ranged between 21 and 63 days (mean 35 days). These results show that the MB/BacT semiautomated system is reliable and faster than the manual culture method and can be used as an alternative for the primary identification of Mycobacterium tuberculosis. The PCR assay allows the fast and exact identification of Mycobacterium tuberculosis directly from positive liquid medium.

Assessment of the functional capacity for intracellular dearth and phagocytosis of polymorphonuclear cells in healthy neonates

The objective of this study was to assess the functional capacity for intracellular death (ID) and/or phagocytic index (PI) of polymorphonuclear cells of 24-h-old healthy newborns with respect to the PMN cells of adults using the same standard exogenous source of opsonins. The ID and PI techniques were standardized and 2-3 ml of blood were used. No differences were found in the percentages of ID, P, PI among the PMNs of the newborns and those of the adults: 43.95 ñ 15.70 vs. 44.56 ñ 8.43 for ID; 38.96 ñ 14.34 vs. 39.00 ñ 14.54 for P; 1.71 ñ 0.54 vs. 1.73 0.45 for PI, respectively. It was concluded that the PMNs of 24-h newborns have an ID, P, PI functionality comparable to adult PMNs; differences observed in PMN function in newborns may be due to humoral deficiencies (opsonins)

Infection of pregnant women with hepatitis B and C viruses and risks for vertical transmission

Pregnant women infected with hepatitis B and C viruses pose a risk for infecting their newborn infants by vertical transmission. We studied 6,253 pregnant women aged 12-49 years for infection with hepatitis b (HBV) and C (HCV) viruses. Infection was diagnosed by measuring IgC antibodies against HBC, HBs, HBe, as well as IgM-HBc and HCV viral antigens with commercially avalible immunoassay kits. HBV infection was detected in 113 cases (1.8 percent), and prevalence was signficantly higher (2.4 percent) in a group of women with a high-risk pregnancy who were attending a perinatology hospital than in healthy pregnant women (1.67 percent, p<0.05). Infection with HBV was significantly higher in women older than 30 years old (p<0.05). HBsAg was found in blood, colostrum and vaginal exudate of two pregnant women; HBsAg was detected in the gastric aspirate but not in the blood of the two newborn infants. HBeAg and IgM-HBc were not detected in any of the smples. DNA-HBV was detected in serum of seven women, and DNA-HBV was detected in the gastric aspiratwe of only one of the newborns. HCV infection was diagnosed in three out of 111 women with markers for HBV infection (2.7 percent), and in 6 out of 1,000 women without these markers (0.6 percent). Anti-HCV antibodies were found in the serum of six of their infants during up to six months of age. Infants were monitored for one year and none of them developed any sign of hepatic disease. These results ksuggest that special attention should be paid to women older than 30 years and with a high-risk pregnanacy, as they are at a higher risk of HBV and HCB infections

Aplicación de la nefelometría laser en inmunología y microbiología / Laser nefelometry immunology and microbiology

Objetivo: evaluar la utilidad de la nefelometría láser en los estudios inmunológicos y microbiológicos. Material y métodos: se realizaron cuantificaciones de diversas proteínas plasmáticas: IgG, IgA, IgM, C3 y C4 por nefelometría laser utilizando como controles los estándares proporcionados por una casa comercial. Para su análisis los datos se transformaron a escalas logarítmicas y se calcularon ecuaciones de regresión lineal. Para la evaluación microbiológica se realizaron concentraciones bacterianas decimales hasta 10 a la 6 de E. coli en caldo de Hinto-Muller. Todas las concentraciones se leyeron cada 5 o 10 minuto durante 70 minutos para determinar la cinética de crecimiento. También se midió inhibición de amikacina sobre E. coli. Resultados: las ecuaciones calculadas empíricamente mostraron una buena reproducibilidad y una vigencia aproximada de seis meses para las proteínas plasmáticas. Así mismo la nefelometría mostró que permite realizar un cálculo rápido de la concentración mínima inhibitoria de crecimiento bacteriano

Prevalencia de marcadores serológicos para los virus B y C de la hepatitis en una cohorte de mujeres embarazadas del Valle de México / Prevalence of serologic markers for virus B and C hepatitis in a cohort of pregnant women from the valley of Mexico

Introducción. Una de las vías de trasmisión de los virus B (HVB) y C (HVC) de la hepatitis es la vertical o perinatal a través de una madre portadora de estos agentes. Material y métodos. En este estudio se investigaron por ELISA marcadores serológicos para HVB y HVC en 6254 gestantes sanas del Valle de México, con edades de 12 a 54 años. Resultados. Se detectó infección previa por HVB (anti-HBc+) en 114 casos (1.82 por ciento), con una P= 0.01 (1.35 vs 2.50 por ciento) entre gestantes de Ciudad Netzahualcóyotl y las del Intituto Nacional de Perinatología. De 6254 muestras, 0.03 por ciento (dos casos) fueron portadores de HVB (HBsAg+). Encontramos 2.7 por ciento (tres casos) positivos para anti HVC en 111 gestantes positivas para anti-HBc. Solamente seis casos (0.6 por ciento de 1000 embarazadas negativas para HVB presentaron anticuerpos contra HVC. Conclusiones. Se observó transmisión transplacentaria de anticuerpos contra virus B o C sin evidencia de infección en nueve de diez recién nacidos estudiados. La transmisión vertical o perinatal no es el principal mecanismo de diseminación de HVB y/o HVC en los grupos familiares analizados