Asociación entre integrones de clase 1 con resistencia a múltiples antimicrobianos y plásmidos conjugativos en Enterobacteriaceae / Class 1 integrons in Enterobacteriaceae and its association with multidrug resistance and conjugative plasmids

La amplia diseminación de genes de resistencia a antimicrobianos es motivo de preocupación. La asociación de los genes de resistencia con elementos génicos móviles favorece su presencia en distintas especies de bacterias, siendo los integrones un elemento importante. En este trabajo se estudia en 123 enterobacterias la presencia de integrones, identificándose éstos en el 20,3 por ciento de las cepas. La asociación entre integrones y resistencia múltiple a antimicrobianos fue estadísticamente significativa (p <0.001). Los aislamientos con integrones fueron con mayor frecuencia, estadísticamente significativa (p <0.05), resistentes a amoxicilina-ácido clavulánico, quinolonas y trimetoprima-sulfametoxazol. Todos los integrones formaban parte de plásmidos conjugativos. La prevalencia de integrones se incrementó del 21,2 por ciento en 1992-1994 al 72 por ciento en 1995-1997 (p <0.001). Los genes aacC1 y aacC2 se identificaron en el 80 por ciento de los integrones. La relación entre integrones y plásmidos conjugativos debe preocuparnos, ya que podría contribuir a la diseminación de los genes de resistencia a antimicrobianos entre diferentes poblaciones bacterianas (AU)

[Class 1 integrons in Enterobacteriaceae and its association with multidrug resistance and conjugative plasmids]. / Asociación entre integrones de clase 1 con resistencia a múltiples antimicrobianos y plásmidos conjugativos en Enterobacteriaceae.

The prevalence of antimicrobial resistance genes is a cause of concern. The combination of antimicrobial resistance genes and mobile genetic elements leads to their widespread presence in different bacterial species, in which integrons are a new and important element. We studied the presence of integrons in 123 unrelated enterobacteria and identified them in 20.3% of the strains. The combination of integrons and multidrug resistance was shown to be statistically significant (p <0.001). Integron-positive isolates were statistically (p <0.05) more likely to be resistant to amoxicillin-clavulanic acid, quinolones and trimethoprim-sulfamethoxazole. All the integrons were identified in conjugative plasmids. The prevalence of integrons increased from 21.2% in 1992-1994 to 72% in 1995-1997 (p <0.001). The aacC1 and aacC2 genes were identified in 80% of the integrons. The relationship between integrons and conjugative plasmids is a matter of concern because it could contribute to the dissemination of antimicrobial resistance genes among different bacterial populations.

Response to standard syphilis treatment in patients infected with the human immunodeficiency virus.

In a study designed to evaluate the efficacy of penicillin in HIV-infected patients with syphilis and to determine the clinical and laboratory responses after treatment, 13 patients with HIV infection and syphilis were assessed at enrollment and at the last follow-up examination (median time of 21 months). The Venereal Diseases Research Laboratory (VDRL) test, the Treponema pallidum hemaglutination test, and leukocyte counts in cerebrospinal fluid were evaluated both at enrollment and at the last follow-up visit, and the polymerase chain reaction for Treponema pallidum DNA and the rabbit infectivity test were performed on cerebrospinal fluid samples at the last follow-up visit. Primary syphilis was confirmed in four patients, latent syphilis in five, and neurosyphilis in four. After penicillin treatment, all patients were asymptomatic. The serum rapid plasma reagin test became negative in five patients, and titers declined in eight. The VDRL test, Treponema pallidum DNA, and the rabbit infectivity test were negative in all 13 patients. Except for one patient whose serological titer was slow to decline, all patients had good clinical and serological responses to penicillin. In certain settings, factors other than penicillin treatment failure should be considered in HIV-infected patients with suspected relapse of syphilis.

Biliary tract infection caused by Haemophilus parainfluenzae.

Haemophilus parainfluenzae was isolated from the bile specimens of 2 patients with acute cholecystitis. The strains were genetically unrelated by the random amplified polymorphic DNA (RAPD). The 2 H. parainfluenzae strains represented 11.7% of all positive bile cultures inoculated in blood culture bottles. The routine inoculation of bile specimens in media able to support growth of Haemophilus species should be considered.

Plasma parathyroid hormone related-protein levels in patients with cancer, normocalcemic and hypercalcemic.

Hypercalcemia in patients with cancer may reflect the synthesis and secretion into circulation of parathyroid hormone-related protein (PTHrP) produced by the tumor. In the present study, we have measured circulating PTHrP concentrations in healthy subjects and patients using a new immunoradiometric assay (IRMA) that is specific for the 1-86 amino acid sequence of molecule, and in plasma collected with protease inhibitors. Plasma concentrations of PTHrP(1-86) were greater than the detection limit of the assay (0.3 pmol/l) in healthy subjects. All patients with hypercalcemia-associated cancer had PTHrP(1-86) levels significantly greater (median 7.74 pmol/l, P < 0.05) than healthy subjects or patients with cancer and normal serum calcium, primary hyperparathyroidism and hyperparathyroidism secondary to chronic renal failure. Plasma PTHrP and corrected serum calcium were correlated in patients with hypercalcemia-associated cancer. In one patient, a marked decrease in PTHrP and calcium levels was observed following surgery. Our results suggest that this IRMA for PTHrP(1-86) may be useful for diagnosis and monitoring of PTHrP-producing tumors induced hypercalcemia.

Automated quantification of TSH in serum by a chemiluminescent enzyme immunometric assay: analytical validation.

Thyroid stimulating hormone (thyrotropin; TSH) in serum was assayed with the Immulite-TSH, a fully automated solid-phase third-generation immunoassay analyzer that has a chemiluminescent detection system. The intraassay CV ranged from 3.6% to 6.2% for TSH mean concentrations from 0.025 to 32.12 mIU/L and the interassay CV ranged from 7.9% to 10% for TSH mean concentrations between 0.023 and 31.93 mIU/L. The analytical and functional detection limits of the assay were 0.001 and 0.0068 respectively. No interference was observed by any of the compounds: bilirubin, triglycerides, and hemoglobin. To compare the accuracy of Immulite-TSH with that of a conventional immuno-radiometric assay (Orion Diagnostica Irma-TSH), we examined 153 patient samples with TSH concentrations ranging approximately 0.2 to 100 mIU/L. At TSH concentration approximately 0.15 the precision was greater for Immulite-TSH than for Irma TSH (3.8% vs 11.87%) intraassay CV and (8.6% vs 35.4%) interassay CV. We concluded that Immulite-TSH is a rapid and precise third-generation assay, totally automated and the results can be provided to the clinician within 1 to 2 h of receipt of the patient's sample.

Serum insulin-like growth factor (IGF) binding protein-3 and IGF-I levels during childhood and adolescence. A cross-sectional study.

To investigate the effect of pubertal development on serum levels of IGF binding protein-3 (IGFBP-3) and IGF-I, and the relationship between IGFBP-3 levels and height, weight, weight for height and age (WFHA), and IGF-I levels, a cross-sectional study was performed in a Spanish basic education school in Vigo (NW Spain). The study was made up of 181 girls with a mean chronologic age of 11.03 +/- 0.22 y and 173 boys with a mean chronologic age of 10.9 +/- 0.23 y. The pubertal development was graded into three groups according to estradiol and testosterone concentrations for girls and boys, respectively. All subjects were in good health and among the 5th and 95th percentile for height. Serum IGFBP-3 and plasma IGF-I concentration was determined by RIA. Pubertal development was significantly associated with IGFBP-3 and IGF-I concentrations in girls and boys, respectively (p < 0.0001, analysis of variance). Multivariate regression analyses between IGF-I or IGFBP-3 with age, sex, and estradiol or testosterone show significative correlation in prepubertal children for IGF-I (r = 0.545, p = 0.0001 and r = 0.574, p = 0.0001 for girls and boys, respectively) and only in prepubertal boys for IGFBP-3 (r = 0.336, p = 0.0012). The linear correlation between IGF-I and IGFBP-3 was significant in both prepubertal (r = 0.25, p < 0.0001) and pubertal (r = 0.40, p < 0.0001) girls, but only in prepubertal boys (r = 0.30, p < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)