[Comparison of 2 dyes in the detection of Pneumocystis carinii]. / Comparación de dos tinciones en la detección de Pneumocystis carinii.

OBJECTIVE: To evaluate two staining procedures used in the detection of P. carinii. MATERIAL AND METHODS: Bronchoalveolar lavage samples were obtained from 20 immunosupressed rats. The samples were stained by three procedures: o-toluidine blue (OTB), Diff Quik (DQ), and a silver stain as the gold standard. The microscopic search for P. carinii was made independently by two observers. RESULTS: Fifteen of the 20 samples were positive to P. carinii with the silver stain. The sensitivity with DQ was 27% and the specificity 100%. With OTB the sensitivity was 93% and the specificity was 80%. The inter-raters' agreement by kappa was 0.11 for DQ and 0.53 for OTB. CONCLUSION: Our results suggest that the silver stain should be used for an adequate diagnosis of pneumonia caused by P. carinii.

Pathogenic and non-pathogenic zymodemes of Entamoeba histolytica in a rural area of Mexico. Concordance with serology.

OBJECTIVES: a) to describe the frequency of pathogenic and nonpathogenic zymodemes of E. histolytica in asymptomatic carriers in rural Mexico, b) to identify the isoenzymatic pattern of the zymodemes and c) to measure the concordance of pathogenic zymodemes and positive serology. DESIGN: Descriptive cross-sectional survey. Reference population: rural communities of the mexican highlands. STUDY UNITS: 2048 individuals from 341 families of 5 rural communities. METHODS: From the local census of each community, 70 to 100 families were selected by random sampling. All members of each family were studied. After obtaining the consent the following activities were done: a) filling of a questionnaire about housing and sanitary condition and structure of the family; age, sex, literacy and digestive symptoms and illness during the previous 4 weeks, in each individual; b) a blood sample for serology (CEIP and IHA) and c) a stool sample for coproparasitoscopic analysis (CPS) and zymodemes identification, in each individual. Statistical evaluation was done by kappa index and receiving operating curves (ROC). MAIN RESULTS: there were 122/1730 (7.1%) CPS studies positive to E histolytica cysts, 100/1730 (5.8%) zymodemes isolated and 137/1886 (7.3%) positive serologic studies. Of the 100 zymodemes 30 had a pathogenic pattern, three had a mixture (pathogenic/nonpathogenic) and 67 had a non-pathogenic patterns. There were two (XVII, XVIII) patterns described for the first time in Mexico. Concordance between pathogenic zymodemes and positive serology (IHA greater than 1:128) was very low, Kappa = 0.05. ROC curves for IHA in pathogenic and non-pathogenic zymodemes showed little relationship between positive serology and pathogenic pattern. CONCLUSIONS: Although the frequency of positive serology, coproparasitoscopic studies and zymodemes identification was similar, the concordance between serology and the coprologic studies was very low. This disagrees with other reports, and deserves further investigation using methodologic standards in design.

Efficacy of zymodemes of E. histolytica technique in an epidemiologic study and report of new zymodemes in Mexico.

OBJECTIVES: To determine the efficacy of zymodemes of E. histolytica technique in an epidemiologic study. To report the zymodemes for the first time described in Mexico. To report the main difficulties in the correct classification of zymodemes in this study. To describe the zymodemes identified in two evaluations done in 100 healthy individuals. DESIGN: A cross-sectional survey and a cohort of healthy persons. METHODS: We analyze the results of 1730 Robinson cultures performed in a cross-sectional survey done in the Municipality of Cadereyta, Queretaro, Mexico from October 1986 to August 1987. From positive cultures properly growth a Iysate was done and preserved in liquid nitrogen until the electrophoretic determination of 4 isoenzymes was done: EC 5.3.1.9. glucophosphate isomerase (GPI); EC 1.1.1.40 L-malate: NADP oxidoreductase (oxaloacetate decarboxylating) (ME); Ec 2.7.5.1 phosphoglucomutase (PGM); and EC 2.7.1.1 hexokinase (HK). RESULTS: Of 1730 cultures 289 (16.7%) developed trophozoites, in 100 (34.6%) was possible to make lysate and zymodeme. There were 67 ZNP, 3 mixtures (ZP and ZNP) and 30 ZP. There were two patterns for the first time described in Mexico (XVII and XVIII) and 30 strains had a pattern different from the 20 already described by Sargeaunt. Results observed in 100 individuals measured twice. [table: see text] There were 9 subjects in which zymodemes were isolated twice: at the first time 5 PZ and 4 NPZ, at the second time 1 PZ and 8 NPZ. At first time all 9 had negative serology and the second time one carrier of NPZ became positive. COMMENTS: In our study one tirth of Robinson cultures positive to trophozoites reached lysate. Efficacy of zymodemes and CPS is similar. We report for the first time in Mexico two non-pathogenic zymodemes (XVII and XVIII). We also report 30 zymodemes non-classified according to the standard proposed by Sargeaunt, one explanation for this feature is the possibility of zymodemes variability or new patterns. In endemic populations zymodeme pattern varies with time in asymptomatic carriers.

Identificacion de antigeno amibiano circulante en el hombre por analisis inmunoenzimatico. I. Desarrollo de la tecnica. / Identification of circulating amebic antigen in man by inmunoenzymatic analysis. I. Development of the technic

Se establecieron las condiciones optimas con dos variedades de analisis inmunoenzimatico (ELISA) para detectar un antigeno soluble obtenido de trofozoitos de E. histolytica. La ELISA de emparedado con doble anticuerpo y antiinmunoglobulina logro detectar hasta 100 ng de antigeno por ml, mientras que con la ELISA de emparedado con doble anticuerpo el limite de deteccion se incremento hasta 1 ng/ml. Estos niveles de deteccion deben ser utiles para identificar antigeno en el suero de pacientes con amibiasis invasora

Detection of antibodies to Salmonella "O" antigens in typhoid fever by counterimmunoelectrophoresis. I. Description of technique.

In the serum of patients with typhoid fever counterimmunoelectrophoretic techniques were used for the detection of antibodies to Salmonella "O" antigen. Lipopolysacharides (LPS) obtained with phenol and water from Salmonella typhi (antigens 0, 9 and 12) were used. Positive results were obtained in those patients with typhoid fever (20). The lower and higher titration levels were 1:8 and 1:32 respectively; the geometric mean was 1:16. The variation coefficient during the intra assay tests was 0.19, and remained stable throughout the inter-assay tests. Reproducibility, as well as a rapid technique, make this test a valuable tool for the serologic diagnosis of typhoid fever.

Detection of antibodies to Salmonella "O" antigens in typhoid fever by counterimmunoelectrophoresis. II. Assessment in patients with typhoid fever and in a healthy population.

Two different population groups were studied. In one, 50 patients with a confirmed diagnosis of typhoid fever. Serum determinations were made for the detection of antibodies to S. typhi somatic antigen using Widal technique, surface fixation test and counterimmunoelectrophoresis (CIE). In the other group, 350 healthy subjects were studied to determine the minimum diagnostic titer by means of CIE. It was possible to establish that a 1:16 titer was suggestive of typhoid fever when CIE techniques were used. Surface fixation test showed the highest sensitivity levels. CIE with sensitivity levels similar to those found in Widal's reaction exceeds the other test because of its standardization and greater reproducibility.