Eficacia de dos genoespecies en el diagnóstico serológico de la infección por Borrelia burgdorferi / Efficacy of two gene species in the serological diagnosis of Borrelia burgdorferi infections

Background: There is phenotypic and genetic variability among the species Borrelia burgdorferi that produces Lyme disease. Three gene species and seven serotypes have been defined. Aim: To study the efficacy of two gene species in the serological diagnosis of Borrelia burgdorferi infections in Granada, Spain. Material and methods: One thousand sixty nine sera coming from 1,251 subjects without Lyme borreliosis were analyzed. These subjects were studied for health or pregnancy controls, differential diagnosis of viral disease, diagnosis of syphilis, neurological or rheumatic diseases. In all samples, antibodies against Borrelia burgdorferi (B31 and Pko strains) and against Treponema pallidum were investigated. Screening tests (ELISA and hemagglutination) were followed by confirmations tests for positive samples (Western Blot IgG strain B31 and FTA-abs respectively). A clinical and laboratory follow up was done for subjects with positive serological tests. Results: The global rate of positive antibodies against Borrelia burgdorferi B31 was 8.31 per cent and against the strain Pko was 0.64 per cent. Western blot was negative in 36 per cent of subjects with positive ELISA B31. The distribution of antibodies against the strain B31 was acute herpes virus infection in 16 per cent, gestation in 3 per cent, HIV infection in 6.4 per cent, T pallidum infection in 36 per cent, rheumatic diseases in 25 per cent, neurological diseases in 17.5 per cent and health controls in 7.4 per cent. The percentage of positive Western Blot analyzes were 0.8, 2.1 and 0.4 per cent respectively. A reversion of positive ELISA tests was observed in 6 subjects. Conclusions: The disparity in rates of antibodies against Borrelia burgdorferi in different geographic regions may be due to differences in the serological tests used. The high rate of false positive ELISA tests underscores the need to use other serological tests

Borreliosis de Lyme: aproximaciones al diagnóstico de laboratorio / Laboratory diagnosis of Lyme borreliosis

Some direct methods that can be used for the diagnosis of Lyme borreliosis are the culture, direct visualization or the detection of microbial DNA using polymerase chain reactions, in body tissues or fluids. Unfortunately, all these methods have a low sensitivity. There is a wide assortment of tests and antigens for indirect diagnosis, and the most recommended are ELISA tests and Western blot. The main inconvenient of these tests are the existence of shared serologic reactions, the variability of immune response and the difficult interpretation of results. Therefore, we propose the following guidelines for the diagnosis of Lyme borreliosis: For sero-epidemiological studies and to diagnose infection, antibodies should be determined in subjects with a compatible clinical picture, using an ELISA test that must be positive in at least two separate samples. All positive ELISA results should be confirmed with Western blot analysis, that must be interpreted using established criteria. Polymerase chain reactions should be used when they are available

Correlación entre la presencia de anticuerpos y antígeno de citomegalovirus en los leucocitos de sangre para el diagnóstico de la infección activa primaria / Cytomegalovirus infection diagnosis measuring antibodies against the virus or the antigen presence in peripheral leukocytes

Background: The diagnosis of cytomegalovirus infections measuring IgG or IgM antibodies has a high rate of false positive or negative results, specially in immunocompromised patients. Aim: To compare the diagnostic yield of antibodies against cytomegalovirus with the measurement of the antigen in peripheral leukocytes. Material and methods: Forty three blood samples coming from pediatric patients with suspected cytomegalovirus infections were analyzed. Low affinity IgG and IgM antibodies against Epstein Barr virus and cytomegalovirus, using indirect ELISA assays, and the virus antigen in peripheral leukocytes, using a commercial immunoperoxidase assay, were measured. Results: Seven patients had positive IgM antibodies against cytomegalovirus. In five of these the viral antigen was detected in peripheral leukocytes. Twenty patients had positive antibodies against Epstein Barr virus, and in 16 patients all serologic tests were negative. Conclusions: There is not a good correlation between antibodies against cytomegalovirus and the detection of its antigen in patients with acute infections

Relación entre el tiempo de evolución de la brucelosis humana y la avidez de anticuerpos IgG específicos / Relationship between evolution time of human brucellosis and the avidity of specific IgG antibodies

The aim of this work was to relate the avidity of specific IgG antibodies with the time of evolution of human brucella infection. IgG anti-brucella antibodies were measured using an ELISA assay with 8 M urea in 17 patients with recent active brucellosis (group I), 31 patients with chronic active brucellosis (group II) and 120 asymptomatic patients with past brucellosis (group III). Twelve patients of group I (70.6 percent), three of group II (9.7 percent) and none in group III had low avidity antibodies against Brucella. It is concluded that these antibodies have a high diagnostic efficiency for recent Brucella infections

Patrón de susceptibilidad a los antimicrobianos de cepas de enterococos / Pattern of antimicrobial susceptibility of enterococci strains

Enterococci resistance to antimicrobials has increased lately. We studied the susceptibility to 12 antimicrobials of 150 enterococci strains coming from hospitalized and outpatients, using the agar dilution method. Teicoplanin, followed by imipenem and amoxicilin-clavulanic acid had the lower minimal inhibitory concentrations. No strains of E faecalis was resistant to ampicillin, whereas 14 percent of E faecium had minimal inhibitory concentrations over 8 µg/ml. The high minimal inhibitory concentrations of cefpirone (64µg/ml) renders this antimicrobial useless in the treatment of enterococcal infections. Betalactamase production and resistance to glycopeptides were not detected. Antimicrobial susceptibility of strains coming for hospitalized or outpatients were similar