Detection of interleukin-2 is not useful for distinguishing between latent and active tuberculosis in clinical practice: a prospective cohort study.

OBJECTIVE: Previous reports have identified interleukin-2 (IL-2), quantified in the supernatants of QuantiFERON®-TB Gold In-tube (QFT) after 72 h of incubation, as a potential biomarker for distinguishing between latent and active tuberculosis (TB). However, its validity has not been tested in an appropriate clinical cohort. METHODS: A multicentre study of 161 consecutive adult patients undergoing evaluation for active TB at eight TB Units in Spain. Interferon-γ (IFN-γ) and IL-2 were assessed in the supernatant of QFT after 16-24 h and 72 h of incubation. The accuracy of IL-2 for indicating latent TB infection (LTBI) was assessed by receiving operating characteristic curves. . RESULTS: Twenty-eight participants were not infected, 43 had LTBI, 69 had TB, and 21 were not classifiable. Median (interquartile range) IL-2 concentrations after 72 h of incubation were 0.0 pg/mL (0.0-0.0) in uninfected individuals, 261.0 pg/mL (81.0-853.0) in LTBI individuals, 166.5 pg/mL (33.5-551.5) in patients with extrapulmonary TB, 95.0 pg/mL (26.0-283.0) in patients with smear-negative pulmonary TB, and 38.5 pg/mL (7.5-178.0) in patients with smear-positive pulmonary TB (p <0.0001). The area under the curve of the receiving operating characteristic curve (95% CI) of IL-2 after 72 h of incubation for the diagnosis of LTBI was 0.63 (0.53-0.74) when all TB cases were considered as a single group, ranging from 0.59 (0.47-0.71) to 0.72 (0.58-0.85) when only extrapulmonary and smear-positive pulmonary TB cases respectively were considered. CONCLUSIONS: Quantification of IL-2 in the supernatant of QFT after a prolonged incubation is not useful to distinguish between LTBI and active disease in clinical practice.

Characterisation of invasive pneumococcal isolates in Catalan children up to 5 years of age, 1989-2000.

Ninety-six Streptococcus pneumoniae strains isolated between January 1989 and December 2000 from usually sterile sites of children aged < 5 years of age were included in the study. Resistance to penicillin (38.6% intermediate, 10.4% high-level), cefotaxime (20.8%), tetracycline (41.7%), chloramphenicol (33.3%) and erythromycin (27.1%), as well as serogroup/type, were related to age and pathology. Strains from children aged < 2 years showed the highest penicillin resistance rate. Resistance to penicillin, tetracycline, chloramphenicol and erythromycin was the most common pattern (18.8% of strains). Most isolates (80.2%) belonged to serogroups/types included in the heptavalent conjugate vaccine.

[Neonatal sepsis by Malassezia furfur.]. / Sepsis neonatal por Malassezia furfur.

We report one case of neonatal sepsis caused by Malassezia furfur in an infant who had been in the Intensive Care Unit for 64 days. She had received prolonged therapy with intravenous fat emulsion. We used Sabouraud's medium with an overlay of sterile olive oil for the blood culture, because we had observed yeast forms in one smear of peripheral blood. M. furfur was isolated after three days of incubation. The patient recovered following removal of the port-a-cath and antifungal treatment, and had no further evidence of fungal infection. The skin colonization by the same yeast was demonstrated.

[Application of molecular amplification methods in the diagnosis and follow-up of HIV-1 infection in children infected by vertical transmission]. / Aplicación de los métodos de amplificación molecular para el diagnóstico y seguimiento de la infección por el VIH-1 en niños infectados por transmisión vertical.

BACKGROUND: To describe the vertical transmission of HIV-1 by means of molecular methods. PATIENTS AND METHODS: A prospective study between 1995 and 1998 of two groups of patients, A: 107 newborn infants to HIV-1 infected mothers, and B: 11 infants with clinical suspicion of HIV infection, born to mothers who didn't know being infected. DNA and RNA PCR as well as reverse transcriptase gen mutations were tested. RESULTS: Eleven infected patients were identified, four from group A and seven from group B. Viral load at the moment of diagnosis was higher than 100,000 copies/ml in all patients. Genotypic mutations of the studied codons were not detected in ten patients. CONCLUSION: Molecular amplification techniques are useful for early diagnosis and follow-up of HIV infection acquired by vertical transmission.

Implant sonication increases the diagnostic accuracy of infection in patients with delayed, but not early, orthopaedic implant failure.

The purpose of this study was to compare the diagnostic accuracy for the detection of infection between the culture of fluid obtained by sonication (SFC) and the culture of peri-implant tissues (PITC) in patients with early and delayed implant failure, and those with unsuspected and suspected septic failure. It was hypothesised that SFC increases the diagnostic accuracy for infection in delayed, but not early, implant failure, and in unsuspected septic failure. The diagnostic accuracy for infection of all consecutive implants (hardware or prostheses) that were removed for failure was compared between SFC and PITC. This prospective study included 317 patients with a mean age of 62.7 years (9 to 97). The sensitivity for detection of infection using SFC was higher than using PITC in an overall comparison (89.9% versus 67%, respectively; p < 0.001), in unsuspected septic failure (100% versus 48.5%, respectively; p < 0.001), and in delayed implant failure (88% versus 58%, respectively; p < 0.001). PITC sensitivity dropped significantly in unsuspected compared with suspected septic failure (p = 0.007), and in delayed compared with early failure (p = 0.013). There were no differences in specificity. Sonication is mainly recommended when there is implant failure with no clear signs of infection and in patients with delayed implant failure. In early failure, SFC is not superior to PITC for the diagnosis of infection and, therefore, is not recommended as a routine diagnostic test in these patients.

Neisseria meningitidis: evolution of penicillin resistance and phenotype in a children's hospital in Barcelona, Spain.

UNLABELLED: Neisseria meningitidis is the most prevalent micro-organism involved in paediatric bacterial meningitis in the Barcelona area in children over 3 mo of age and it is an important cause of morbidity and mortality in Spain. A total of 498 strains of N. meningitidis, obtained between the years 1986 and 1997 from children with sepsis and/or meningitis, were characterized according to their serogroup and penicillin resistance; their distribution in serotypes and subtypes was studied from 1990. A decreasing tendency in the number of annual isolates was observed in this period. Most isolates belonged to serogroups B (403 strains) and C (77 strains). Serogroup C accounted for 1.8% of the strains in 1986 and 57.1% in 1997. The most prevalent phenotype between 1990 and 1996 was B:4:P1.15. but C:2b:P1.2,5 was the most prevalent in 1997. Overall penicillin-resistance rates ranged from 9.1% in 1986 (when a non-susceptible strain was isolated for the first time in the Hospital Sant Joan de Déu, Barcelona, Spain) to 71.4% in 1997, and it was more common among strains belonging to serogroup C (52% of resistant strains) than to serogroup B (22.1 % of resistant strains). The penicillin-resistance level was low, MIC always < or = 0.5 microg/ml. The present increase in N. meningitidis group C isolates, mainly C:2b:P1.2,5, and the availability of preventive measures for this highly pathological and resistant phenotype, argues strongly for the establishment of an epidemiological monitoring system. Detection of penicillin resistance should be standardized worldwide in order to unify data from all laboratories. CONCLUSION: A shift between serogroups B and C is observed in Barcelona from 1986 to 1997, as well as a rapid distribution of decreased penicillin susceptibility.

[Antibiotic sensitivity of Streptococcus pyogenes in pediatrics]. / Sensibilidad antibiótica de Streptococcus pyogenes en pediatría.

BACKGROUND: The purpose of this study was to set up the current level of Streptococcus pyogenes sensitivity, in pediatric patients in our community, to penicillin, clindamycin, clarithromycin, erythromycin and azithromycin. MATERIAL AND METHODS: 100 strains were collected between October 1996 to July 1997. 79 were pharyngeal and 21 were non-pharyngeal strains. The MICs were obtained by the E-test method, and furthermore the results were compared by the Kirby-Bauer method. RESULTS: All strains were sensitive to penicillin and except one (inducible resistance) to clindamycin. 19% were resistant to macrolide, without differences among clarithromycin, erythromycin and azithromycin. From 13 strains (16.5%) of pharyngeal and 6 (28.5%) from non-pharyngeal samples, 4 of these from cutaneous samples, showed resistance. 18 of the resistance strains belonged to novel resistance fenotip and one to 10 inducible fenotip. Only minor discrepancies about erythromycin and clindamycin were observed between E-test and Kirby-Bauer methods. CONCLUSIONS: This study confirms a remarkable level of resistance to macrolides in pediatric patients, mainly in the cutaneous samples. Due to the reduced prevalence of macrolide-susceptible strains, in vitro susceptibility testing appears necessary in case of macrolide chemotherapy.

[Evaluation of a simple rapid polymerase chain reaction (PCR) technique for the diagnosis of Helicobacter pylori infection in childhood]. / Evaluación de una técnica de reacción en cadena de la polimerasa (PCR) rápida y sencilla para el diagnóstico de la infección por Helicobacter pylori en la infancia.

BACKGROUND: The purpose of this study was to evaluate the use of polymerase chain reaction (PCR) applied to the diagnosis Helicobacter pylori infection in the pediatric population, by means of a rapid and simple method of extraction and posterior detection by a colorimetric hybridation of amplified H. pylori DNA. METHODS: Fifty three gastric biopsies, obtained through upper gastrointestinal endoscopy from 53 patients with gastric pathology (45 recidivant abdominal pain and eight hematemesis), were processed from october 1995 to july 1996. Three non invasive tests were performed: detection of IgG by (Cobas) Core Anti-H. pylori EIA (Roche), breath test with 13C-urea and PCR of dental plaque, as well as four invasive ones: histologic study, culture into selective (Pylori Agar, bioMérieux) and non selective media (Columbia Agar with 5% sheep blood, bioMérieux), test of rapid urease and PCR of gastric biopsies. A 20% solution of Chelex 100 resin (DNA Extraction Reagen, Perkin Elmer) was used for DNA extraction, amplification was performed from gen ureA (Clayton, 1992) and amplified DNA was detected by colorimetric hybridation (PCR ELISA, Boehringer, Mannheim). Duration of the PCR process was: extraction 25 min, amplification two hours and detection three hours. RESULTS: Results of culture and PCR from gastric biopsies agreed in 84.3% of cases (27 positives, 16 negatives and two not determined). Two samples were positive by culture and negative by PCR, and were considered as PCR false negatives due to positivity of three or more other tests. Six samples were negative by culture and positive by PCR, being considered as culture false negatives due to positivity of three or more other tests. Sensitivity of PCR and culture was 94.2 and 82.8%. Specificity was 100% for both tests. None of the dental plaque samples was positive. CONCLUSIONS: When invasive techniques are to be done for microbiologic diagnose of H. pylori, PCR increases the confirmation rate of infection; the present procedure enables daily routine work due to its simplicity and its short turnaround time.

[Helicobacter pylori infections: antigen detection in stool samples]. / Infecciones por Helicobacter pylori: detección de antígeno en muestras fecales.

BACKGROUND: The aim of this study is to evaluate a new diagnostic test to detect Helicobacter pylori antigen in stool samples (HpSA), and compare the results with those obtained by standard techniques (rapid urease test,culture, histological examination of gastric biopsy specimens,13C-urea breath test and serology), in a paediatric population with gastrointestinal symptomatology. PATIENTS AND METHODS: Sixty patients with dyspeptic symptoms (37 females and 23 males;mean age 10.9 years) attending the Gastroenterology Service were included in the study. Exclusion criterium was previous treatment with proton pump inhibitors, bismuth compounds or antibiotics. Rapid urease test, culture and histologic study of gastric biopsies,13C-urea breath test and serology, as well as HpSA, were performed to all patients. RESULTS: Forty seven patients were considered infected by H.pylori on the basis of bacterium isolation and 13C-urea breath test positivity. HpSAwas detected in 45 of the 47 H.pylori positive patients(95.7%). There were no HpSA false positive. CONCLUSION: Our results show that this new test is highly sensitive (95%) and specific(100%) for detection of H. pylori infection. It has some advantages over other non invasive techniques: it is easy to perform,requires no blood samples and its cost is lower than that of 13C-urea breath test.

[Study of the viral etiology of lower respiratory tract infections in a neonatal unit]. / Estudio de la etiología viral de las infecciones del tracto respiratorio inferior en una unidad de lactantes.

OBJECTIVE: To study the possible viral etiology in 139 infants with lower respiratory tract infection who required hospitalization in the Infant Unit of our hospital, from October 1994 to June 1995. PATIENTS AND METHODS: 139 patients were admitted, aged from 13 days to 14 months, during this period. The etiological agent was detected by direct immunofluorescence from nasopharyngeal secretions. Monoclonal antibodies were used against Respiratory Syncitial Virus, Influenza A Virus, Influenza B Virus, Adenovirus and Parainfluenza 3 Virus. Antibody detection against these viruses by Complement Fixation Test was done on 29 of these patients, with paired sera (acute and convalescent phase). RESULTS: In 82 patients (59%) we found at least one viral agents from the nasopharyngeal specimens, but in 64 of these only one was detected, in the remaining 18, there were more than one. Significant levels of antibodies were detected in only six of the 29 patients tested. Serology was negative in the remaining 23 patients. CONCLUSIONS: Syncitial Respiratory Virus is the first virus responsible for the lower respiratory tract infection in this age group (49%). There was no correlation between serological diagnosis and antigen detection.

[Cutaneous colonization by Malassezia spp. in neonates]. / Colonización cutánea neonatal por Malassezia spp.

BACKGROUND: Malassezia spp. is a lipophilic yeast considered to be a normal component of the human skin flora. It has been associated with sepsis in patients receiving intravenous infusion of lipid emulsions through central venous catheters (CVC). Current evidence indicates a high rate of skin colonization in healthy adults, in contrast with the low rate of colonization in prepubertal children. Of note is the high prevalence of colonized infants in the neonatal intensive care unit (NICU). METHODS: We performed a prospective open observational study of colonization in all infants admitted to the NICU during a nine-month period (October 1997-June 1998). Length of stay in the unit, birthweight and the use of CVC for parenteral fat infusion were evaluated. RESULTS: Seventy-seven neonates were included in the study. The mean length of stay in the NICU was 24 days. A total of 63.6 % weighed less than 2,500 g at birth and 72 % were given parenteral nutrition supplemented with fat emulsion through a CVC. The overall rate of colonization in the unit was 41.5 and 75 % of the patients became colonized within the first two weeks of admission. CONCLUSIONS: These data emphasize the need for preventive measures to reduce the transmission of these yeasts in the NICU and to prevent the occurrence of neonatal sepsis due to Malassezia spp. in immunologically immature infants.