[A new trichromic safranin stain for the detection of Cryptosporidium parvum, Cyclospora cayetanensis, species of Microsporidia and Isospora belli in fecal material]

Cryptosporidium parvum, Isospora belli, Cyclospora cayetanensis and Microsporidia are frequent pathogens in the immunodeficient host, which may cause multiple infections. The above mentioned parasites are found in feces by the application of different specific tintorial techniques. The objective of this work was the development of a stain for the simultaneous detection of these parasites, reducing costs as well as the time taken to make the diagnosis. The safranin-trichrome stain is simple, chip and its results are similar to those of specific tints. All microorganisms are easy to detect and besides being perfectly distinguishable from fungi and faecal elements.

[Parasitosis in an adult population with chronic gastrointestinal disorders]

We worked with 185 middle-class patients above 18 years of age, both sexes, who presented diarrhea and/or chronic gastrointestinal disorders. The faeces were collected serially in formol 10% and processed in the following way: direct microscopy, with and without wet staining, concentration by Ritchie's method, 1% safranine technique for a specific investigation of Cryptosporidium sp., and faecal sieving macroparasites. Twenty eight point six of the studied patients showed at least one enteroparasite in their faeces, 48 harboured one parasite and 5 harboured two parasites. The following parasites were found and their corresponding percentages in the entire studied population are given below: Blastocystis hominis 15.7%, Giardia lamblia 7.5%, Cryptosporidium sp. 1.6%, Entamoeba coli 3.3%, Chilomastix mesnilii 1.1%, Ancylostoma duodenale-Necator americanus 0.5%, Ascaris lumbricoides 0.5%, Enterobious vermicularis 0.5% y Endolimax nana 0.5%. The most frequently found enteroparasites in the positive patients were B. hominis and G. lamblia. Cryptosporidium sp. was diagnosed in only three patients. The source of infection could be presumed in all of them. The symptomatology coincided with that described for this coccid in the bibliography. In spite of the fact that they were HIV seronegative patients the diarrhea was not self-limiting, but the immunologic profile of their relatives remained unknown and no other cause of immunosuppression could be detected with justified chronicity. The treatment with spiramycin was effective. Giardiasis was found in 17 patients, and the source of infection could not be inferred in any of them. They all had chronic diarrhea and their most frequent symptoms were abdominal pain, metallic taste, flatulency and nausea. Most of these patients were harboured one parasite, and only 2 of them simultaneously presented another faecal parasite associated to G. lamblia. Treatment with metronidazole was successful in all of them. Twenty nine patients were found to have B. hominis. The source of infection could not be inferred, this amoeboid was present as the only parasite in 25 patients. Predominant symptoms were flatulence, abdominal distention and colis. All patients suffered from chronic diarrhea, alternating, in some cases, with constipation. Good therapeutic results were obtained with metronidazole. Considering that one third of the patients examined presented faecal parasites associated to chronic disorders, it is important to insist on the detection of parasites to chronic disorders, it is important to insist on the detection of parasites using appropriate diagnostic techniques since the application of specific therapy made their eradication possible as well as relieving the patients' symptomatology.

[Pneumocystis carinii pneumonia: laboratory diagnosis]

We worked with 51 samples, 7 bronchoalveolar lavages (BAL) and 44 sputa (S) of 31 AIDS patients with clinical and radiographic symptoms compatible with Pneumocystis pneumonia. With the aim of finding a specific sensitive methodology for the diagnosis of Pneumocystis carinii, we evaluated 4 coloration techniques (silver methenamine, its modification without gold chloride, toluidine blue and Giemsa). 35% of the patients studied were positive. P. carinii were observed in 18% of the 44 sputa. We observed that the analysis of a single sputum sample (S) has a very low sensitivity and that the processing of two or more samples is necessary since only one of the 14 patients who had sent a single sample was found P. carinii positive, while in the remaining ten who had sent more than one (S) sample, the microorganism was detected in 50%. 4 of the 7 BAL were positive. 4 BAL were preceded by the analysis of an (S) sample: in two cases the results were negative while BAL allowed us to make the diagnosis, thus demonstrating its greater efficacy. To enhance sensitivity each sample was centrifuged until exhaustion and 10 slides were prepared for coloration with the final sediment. The four techniques employed were specific and all the Pneumocystis pneumonia patients responded to the treatment. Silver methenamine, its modification without gold chloride, and toluidine blue were very sensitive, in contrast to of Giemsa. The stain to be chosen is either silver methenamine, or its modification, because both achieve the best contrast, allowing optimum P. carinii identification. We suggest the implementation of some of these techniques in laboratory routine.

[Importance of the diagnosis of Blastocystis hominis in the parasitological examination of feces]

Feces of 798 male and female patients who attended the Parasitology Laboratory of the "Facultad de Ciencias Bioquímicas y Farmacéuticas de la Universidad Nacional de Rosario (República Argentina)" were examined. Out of the total number of samples, 281 were collected after a purgative, and 517 by serial collection. The samples were examined applying the routine parasitological analysis. Those which presented Blastocysts hominis were processed for their quantification and classification in different categories according to the number of cells per microscopic field with a magnification of 400 x. B. hominis appeared in 25.2% of the patients. Practically the same percentage was detected with either collection method. B. hominis was associated with other parasites, appearing as the only parasite in only 29.4% of the cases. Both its statistical association with the patient's age and its independence from sex were determined. The most frequent symptomatology in patients with B. hominis only was: abdominal pains, pruritus, flatulence, malaise, anorexia and diarrhea. Only 14.9% did not present any symptoms at all. The search for this protozoa should be a parasitological routine analysis since it is the cause of frequent intestinal disorders.

[Presence of Cryptosporidium sp. in diarrheic feces of a population of children]

Searching for Cryptosporidium sp., we examined (throughout a year) 300 samples of feces belonging to 210 diarrheic children assisted at the Hospital Provincial del Centenario. Their ages ranged from a week to thirteen years, though most of them were not older than three years. Feces were collected in 10% formol, enriched by the formol-ether method and stained with safranine 1% and modified Ziehl Neelsen permanent techniques. Cryptosporidium oocysts were detected in 16 out of the 210 children examined (7.6%). The number of oocysts in positive samples was from moderate to abundant, with the exception of one child who showed a very low number of oocysts. Additional samples of only 5 out of these 16 children were obtained. In 3 of them the sample became negative. In none of the positive patients, trophozoites, cysts, sporocysts, eggs or any other enteroparasite larvae were simultaneously detected. The search for Cryptosporidium sp. in diarrheic children should be considered a parasitological routine for a differential etiological diagnosis.