Structural characterization of a Type B chloramphenicol acetyltransferase from the emerging pathogen Elizabethkingia anophelis NUHP1

Elizabethkingia anophelis is an emerging multidrug resistant pathogen that has caused several global outbreaks. E. anophelis belongs to the large family of Flavobacteriaceae, which contains many bacteria that are plant, bird, fish, and human pathogens. Several antibiotic resistance genes are found within the E. anophelis genome, including a chloramphenicol acetyltransferase (CAT). CATs play important roles in antibiotic resistance and can be transferred in genetic mobile elements. They catalyse the acetylation of the antibiotic chloramphenicol, thereby reducing its effectiveness as a viable drug for therapy. Here, we determined the high-resolution crystal structure of a CAT protein from the E. anophelis NUHP1 strain that caused a Singaporean outbreak. Its structure does not resemble that of the classical Type A CATs but rather exhibits significant similarity to other previously characterized Type B (CatB) proteins from Pseudomonas aeruginosa, Vibrio cholerae and Vibrio vulnificus, which adopt a hexapeptide repeat fold. Moreover, the CAT protein from E. anophelis displayed high sequence similarity to other clinically validated chloramphenicol resistance genes, indicating it may also play a role in resistance to this antibiotic. Our work expands the very limited structural and functional coverage of proteins from Flavobacteriaceae pathogens which are becoming increasingly more problematic.

[Clinical and microbiological study of mycetomas at the Muñiz hospital of Buenos Aires between 1989 and 2004]

This work presents clinical, microbiological and outcome data collected from 76 patients with mycetomas at the Muñiz Hospital from 1989 to 2004. Forty-nine patients were male and 27 female; the mean age was 43.4 years. The majority of the patients acquired the infection in Argentina: the most affected provinces were Santiago del Estero with 31 cases, and Chaco with 11; 8 cases came from other countries (Bolivia 6 and Paraguay 2). The mean evolution of the disease was 9.2 years. The most frequently observed sites were: feet 63 cases, ankles 3, and knees 2. Forty-eight patients had bone lesions and 5, adenomegalies. The following etiological agents were identified: Madurella grisea 29 cases, Actinomadura madurae 26, Scedosporium apiospermum 5, Nocardia brasiliensis 5, Acremonium spp. 4 (Acremonium falciforme 2, Acremonium kiliense 1, Acremonium recifei 1), Madurella mycetomatis 3, Fusarium solani 2, Nocardia asteroides 1 and Streptomyces somaliensis 1. The main drugs used in the treatments were ketoconazole and itraconazole for maduromycotic mycetomas, and cotrimoxazole associated with ciprofloxacin or amikacin for actinomycetic mycetoma. Six patients had to undergo amputation, 25 cases achieved complete clinical remission and 34 showed remarkable improvement.

[Successful discontinuation of antifungal secondary prophylaxis in AIDS-related cryptococcosis]

The clinical and laboratory data of 22 patients with AIDS related cryptococcosis who were able to interrupt antifungal secondary prophylaxis after HAART administration, are presented. They were 14 males and 8 females, between 15 and 50 years old (X: 34 years old). All patients presented fever and severe deterioration of their general health status, and 19 exhibited a meningeal syndrome. At the start of antifungal treatment, 59% of the cases presented < 50 CD4+ cells/microl, the median viral burden was 134,804 RNA copies/ml and the median titer of serum cryptococcal antigen was 1/3,000. Amphotericin B by intravenous route, (0.7 mg/kg/day) or fluconazole (600 to 800 mg/day) were given as a treatment of the initial episode, up to CSF cultures negativization. Oral fluconazole (200 mg/day) or intravenous amphotericin B, 50 mg twice a week, were given as a secondary prophylaxis. The secondary prophylaxis was interrupted when the patients had received HAART for an average lapse of 19 months (6 to 36 months) and the median CD4+ cell count was 249/microl. The follow up after secondary prophylaxis discontinuation lasted for a median lapse of 22 months. These data seem to show that secondary prophylaxis is not necessary when the patient are clinically asymptomatic and the CD4+ cell counts are above 150/microl.

Improved radioiodination of biomolecules using exhaustive Chloramine-T oxidation

To improve standardization in analytical reagents we investigated Chloramine-T radioiodination (125I) of several biomolecules based on the use of a single amount of the oxidizing agent Chloramine-T as the limiting reagent being exhausted during the course of the reaction. Whenever the labeling yield resulted in less than one atom 125I/molecule, a second amount of the oxidizing agent was added. Thereafter, the integrity of the various biomolecules was assessed using radioimmunoassays, radioreceptor binding assays, or radioimmunometric assays. Purification yields were done by gel permeation (56% +/- 19%, n=230) or by precipitation with trichloroacetic acid (59% +/- 19%, n=230). Specific activity (117 +/- 61 MBq/nmol) and the degree of iodine incorporation (1.4 +/- 0.8 atoms of 125I/molecule) were achieved after 300 sec of incubation. A second addition of Chloramine-T resulted in an increased labeling yield of all biomolecules tested by a mean factor of 1.8 +/- 0.9. After the second addition of Chloramine-T, we observed for some biomolecules a significant (p<0.001) decreased effect in biological performance. In conclusion, the use of Chloramine-T as a limiting reagent resulted in molecules with appropriate immunological and biological performance. In general, tracers were minimally damaged and assessment of the shelf life as well as storing conditions showed the usefulness of the standardization of biomolecule labeling.

Mycoses associated with AIDS in the Third World

Despite advances in diagnosis and treatment, the epidemiological status of the human immunodeficiency virus (HIV) infection is far from under control in most of the developing world. Sub-Saharan Africa, Southeast Asia and India show increased rates of new infections. In Latin America and the Caribbean there were 1.6 million estimated cases of HIV-infected patients at the end of 1997. Fungal diseases have been one of the most relevant diagnoses in relation to the acquired immunodeficiency syndrome (AIDS). Infections due to Candida species and Cryptococcus neoformans var. neoformans are common worldwide. Histoplasma capsulatum, Coccidioides immitis and Penicillium marneffei are important causes of disease in endemic areas. Infection due to Sporothrix schenckii, Blastomyces dermatitidis and Paracoccidioides brasiliensis are uncommon even where they are endemic. Phaeohyphomycetes, hyalohyphomycetes and zygomycetes are still rare as a cause of disease among AIDS patients. However, agents pertaining to these groups, such as Aspergillus spp., have an increasing incidence. Superficial mycoses due to dermatophytes have special features from epidemiological, clinical and therapeutic points of view.

[Domiciliary noninvasive positive pressure ventilation in chronic alveolar hypoventilation]

Effectiveness of treatment with domiciliary nocturnal noninvasive positive pressure ventilation is analyzed in a group of patients with chronic alveolar hypoventilation of different etiologies. It was applied with two levels of pressure (BiPAP) via nasal mask. Criteria for evaluation were symptomatology and improvement in gas exchange. Data were analyzed by Student t tests. A total of 13 patients were included, mean age 55.7 range 20 to 76 years (5 male 8 female). Main diagnosis was tuberculosis in 6, four of them having had surgical procedure (thoracoplasty 2, frenicectomy 1 and neumonectomy 1), myopathy 3 (myasthenia gravis 1, muscular dystrophy 1 and diaphragmatic paralysis 1), obesity-hypoventilation syndrome 1, escoliosis 1, bronchiectasis 1 and cystic fibrosis 1. These last two patients were on waiting list for lung transplantation. At the moment of consultation, the symptoms were: dysnea 13/13 (100%), astenia 13/13 (100%), hypersomnolency 10/13 (77%), cephalea 9/13 (69%), leg edema 6/13 (46%), loss of memory 6/13 (46%). Regarding gas exchange, they showed hypoxemia and hypercapnia. Mean follow up was of 2.2 years (range 6 months to 4 years). Within the year, all 13 patients became less dyspneic. Astenia, hypersomnolency, cephalea, leg edema and memory loss disappeared. Improvement in gas exchange was: PaO2/FiO2 from 269 +/- 65.4 (basal) to 336.7 +/- 75.3 post-treatment (p = 0.0018). PaCO2 from 70.77 +/- 25.48 mmHg (basal) to 46.77 +/- 8.14 mmHg (p = 0.0013). Ventilatory support was discontinued en 5 patients: three because of pneumonia requiring intubation and conventional mechanical ventilation, two of them died and one is still with tracheostomy; One patient with bronchiectasis and one with cystic fibrosis were transplanted. The remaining eight patients are stable. In conclusion, chronic alveolar hypoventilation can be effectively treated with domiciliary nocturnal noninvasive ventilation. Long term improvement in symptomatology and arterial blood gases can be obtained without significant complications.

[Acute eosinophilic pneumonia. Case report and review of the literature]

A 37 year old female smoker was admitted with an acute episode of fever and pulmonary infiltrates followed by respiratory failure requiring mechanical ventilation in less than 24 hours. After empiric antibiotic therapy fiberoptic bronchoscopy and bronchoalveolar lavage (BAL) were carried out. Abnormal findings were limited to highly increased eosinophilic count in BAL. Blood eosinophils were normal. Acute eosinophilic pneumonia was diagnosed and methyl prednisolone was administered; 48 hours afterwards, infiltrates had partially resolved and the patient was weaned from ventilator. After two years follow up, she has not had recurrences of the episode, is asymptomatic and her chest Xray is normal. A review of the literature is presented and physiopathological mechanisms for acute eosinophilic pneumonia are considered. Acute eosinophilic pneumonia is a rare but potentially curable cause of respiratory failure that should be included in diagnostic considerations.

The usefulness of blood culture in diagnosing HIV-related systemic mycoses: evaluation of a manual lysis centrifugation method

The results of 5034 blood cultures, implementing a lysis-centrifugation method with saponin, are summarized in this paper. Three hundred and twenty-two blood samples (6.3%) obtained from a pool of human immunodeficiency virus (HIV)-positive patients yielded fungi. Cryptococcus neoformans was isolated in 199 samples (3.95%), Histoplasma capsulatum in 95 (1.89%). Candida parapsilosis in 12 (0.23%), C. albicans in 7 (0.13%), C. tropicalis in 2, C. krusei in 1, C. guillermondii in 1, and Prototheca wickerhamii in 4 (0.07%). Blood cultures were positive for C. neoformans in 76.23% of patients having a diagnosis of cryptococcosis and in 89.65% of those who had histoplasmosis. The blood culture was the first means of confirming the diagnosis in 23.8% of the patients with cryptococcosis and in 54% with histoplasmosis. In the four patients in whom P. wickerhamii was isolated, a diagnosis of disseminated protothecosis was not achieved by other findings. Catheter infections were responsible for the majority of recovered Candida spp.

[Respiratory cryptococcosis in HIV positive patients.]

Although the lungs are the portal of entry of the infection, respiratory manifestations of AIDS related cryptococcosis have not been very well studied. The lack of typical findings in clinical and roentgenographic studies and the difficulties in the interpretation of the isolation of Cryptococcus neoformans from bronchial secretions, is probably the explanation for the lack of interest on this subject. The clinical and microbiological findings of 22 HIV positive patients, who presented C. neoformans in their respiratory tract clinical samples, are presented. Seventeen were males and 5 females, their age average was 30.8 years (21-50 years) and the following risk factors for HIV infection were detected: intravenous drug abuse 18, heterosexuals with several sexual partners two, one female prostitute and 1 homosexual man. All patients, except three, showed less than 100 CD4+ cells per microl. The following symptoms were observed: fever, cough, mucoid expectoration and chest ache. Roengenographic studies presented diffuse infiltrative patches in eleven cases, pulmonary cavities in three, pseudotumoral nodules in two, pneumonic infiltration in two and pleural effusion in four patients. C. neoformans was observed and/or isolated from sputum in nine patients, from bronchoalveolar lavage in seven, from lung biopsy in one and from pleural effusion in four cases. Blood cultures for C. neoformans were positive in 13 cases, urine cultures in 10 and in 11 patients C. neoformans was isolated from C.S.F. The latex agglutination tests for C. neoformans capsular polysaccharide rendered positive results in serum samples from 19 patients and from C.S.F. in 14 cases. Seven cases also presented active tuberculosis. According to these findings, it seems that the isolation of C. neoformans from bronchial secretion of HIV positive patients is a signal of disseminated cryptococcosis. It is important to isolate C. neoformans or detect its capsular antigen from other clinical samples in order to confirm the diagnosis of disseminated cryptococcosis. As observed in other studies, pleuropulmonary cryptococcosis does not present a typical clinical pattern.

[Study of eight cases of coccidioidomycosis in a hospital of Buenos Aires.]

Some clinical, epidemiological and diagnostic aspects from eight patients with chronic coccidioidomycosis (five pulmonary and three disseminated), diagnosed in the Muñiz Hospital, were retrospectively analyzed. At diagnosis, lung cavitation and hemoptysis were present in five and four patients, respectively. Smoking (three cases) and alcoholism (two cases) were the most frequent predisposing factors. Diagnosis was achieved by microscopy and cultures from sputum (five cases), tongue and lymph node biopsies and scraping of cutaneous lesion achieved diagnosis. At diagnosis, most patients had positive coccidioidin skin test and serology. Four patients were born within the endemic area and two worked in contact with the soil of the same area.

[Non invasive ventilation in acute respiratory insufficiency: an alternative]

Effectiveness of non invasive positive pressure ventilation (NIPPV) was prospectively evaluated in 22 selected patients with acute respiratory failure, meeting criteria for orotracheal intubation and conventional mechanical ventilation. Patients were divided in two groups: group A (17 patients) with initial PaCO2 above 45 mm Hg and group B (5 patients) with initial PaCO2 below 45 mmHg. NIPPV was administered with 2 levels of pressure either by nasal or facial mask. Respiratory rate (RR), arterial blood pH, PaCO2 and PaO2/FiO2 were registered pretreatment, 1 hour and 24 hours after NIPPV. Statistical analysis was performed by ANOVA test, p < 0.05 was considered significant.

RESULTS

In group A there was a reduction in RR (X +/- DS) from 31.2 +/- 8.2 to 24.7 +/- 8.2 at one hour (h) (p = 0.02) and to 23.4 +/- 6.5 at 24 hs (p = 0.01), pH change from 7.33 +/- 0.07 to 7.37 +/- 0.07 at one hour (p = 0.13) and to 7.40 +/- 0.07 at 24 hs (p = 0.01), a PaCO2 change from 69.5 +/- 19.6 to 57.8 +/- 16.9 at one hour (p = 0.06) and to 54 +/- 13 at 24 hs (p = 0.02), and PaO2/FiO2 change from 187.3 +/- 60.2 to 223.9 +/- 6.5 at one hour (p = 0.12) and to 245.8 +/- 75 at 24 hs (p = 0.03). In group B there was a change in RR from 33 +/- 16.3 to 26.6 +/- 12.5 at one hour (p = 0.46) and to 21.3 +/- 4.2 at 24 hs (p = 0.27), PaO2/FiO2 change from 113.4 +/- 31 to 137.8 +/- 57.2 at one hour (p = 0.44) and to 208.7 +/- 51.2 at 24 hs (p = 0.03). Only two patients in group A and one in group B were converted to conventional ARM.

CONCLUSION

1) NIPPV is a therapeutic alternative for selective patients with acute respiratory insufficiency and may reduce known morbidity of conventional mechanical ventilation. 2) In the group with hypercapnic acute respiratory failure the improvement in respiratory function begins with an immediate reduction in RR. Significant improvement in arterial blood gases usually occurs within 24 hours of NIPPV.

Cryptococcosis associated with AIDS in the Muñiz Hospital of Buenos Aires

Some epidemiologic, diagnostic and immunologic aspects of 93 (75 males and 18 women) cases of cryptococcosis (CRY) associated with AIDS, hospitalized in the Muñiz Hospital (MH) in Buenos Aires during 1994, were retrospectively studied. The median age (MA) of the patients under study was 28 years (17-49 y); 30 (17-49) y for males and 23 (22-34) y for women. Intravenous drug addiction (34% of patients) and homo/bisexuality in men (17%) were the most frequent risk factors for HIV infection. The MA of these groups were 27.5 (17-41) y and 34 (25-41) y, respectively. Microscopic CSF examination with India ink and the blood cultures (lysis-centrifugation) achieved the diagnosis of CRY in 67 (72%) and 16 (17%) patients, respectively. At diagnosis, the median titers for Cryptococcus neoformans capsular antigen were 1/1,000, 1/100 and 1/1 in serum, CSF and urine, respectively. Sixty five strains of C. neoformans were insolated from clinical samples; all were identified at variety neoformans employing the culture medium proposed by Salkin & Hurd and the D-proline assimilation test. At diagnosis, CD4+ lymphocytes counts were < 50/microliter in 46 patients (83.63%), and were between 51 and 200/microliter in 9 (16.4%). The CD4+/CD8+ ratio was < 1 in all patients. Most patients were born (83%) and lived at diagnosis (96%) in Buenos Aires (Bs As) city, Bs As outskirts towns and cities located in Bs As province.

[Study of some epidemiological aspects of 253 cases of cryptococcosis.]

Some epidemiological characteristics of 253 cases of cryptococcosis (CRY) diagnosed between 1981 and 1993 in the Muñiz Hospital (MH) of Buenos Aires City, were studied. The incidence of CRY associated with AIDS (CRY+AIDS) in the MH during 1983-1993, could be divided into 3 periods: between 1983 and 1988 1-3 cases a year were diagnosed; during 1989-91, the number of cases dopubled annually and in 1992-93 the annual increment was lower. CRY associated with predisposing causes other than AIDS (CRY+non AIDS) exhibited an annual incidence of 0-3 cases during the whole period studied. CRY was more frequent in males (86%). The difference between sexes was more evident in CRY+AIDS patients (88% males) than CRY+non AIDS ones (65% males). The median age (MA) of the studied population was 28 (range 10-71) years; 27 (10-48) in women and 29 (17-71) in men. CRY+AIDS and CRY+non AIDS patients exhibited a MA of 29 (17-51) and 40 years (10-71), respectively. AIDS was the predisposing factor in 92% of patients; 65% of them were intravenous drug abusers and 22% homosexual males, with a MA of 27 (17-40) and 33 (23-55) years, respectively. Cryptococcus neoformans var. neoformans was isolated from all CRY+AIDS and 79% of CRY+non AIDS patients and the gattii variety (Serotype B) produced 4 (21%) cases of CRY+non AIDS.

[A cutaneous ulcer induced by fungi of the genus Fusarium]

A case of cutaneous hyalohyphomycosis, due to Fusarium oxysporum, in a 40 years old man is presented. The patient came from Paraguay where he worked in a tropical rural area. His disease had begun 2 months before his admission as a skin ulcer located in the left leg. Clinical characteristics, diagnosis methods, differential diagnosis with other ulcers of the legs in tropical areas as well as therapeutic measures are discussed in this presentation.

Detection of Cryptococcus neoformans capsular polysaccharide antigen in asymptomatic HIV-infected patients

Serum samples from 242 HIV-positive persons were studied for the detection of capsular polysaccharide antigen of Cryptococcus neoformans; 193 of these patients presented less than 300 CD4+ cells/microliters of blood and 49 patients had more than 300 CD4+ cells/microliters. None of them had symptoms or signs characteristic of cryptococcosis. The capsular antigen of C. neofarmans was detected by latex agglutination technique with pronase pretreatment (IMMY, Crypto-Latex Antigen Detection System, Immunomycologics Inc., OK, USA); in 61% of the samples, ELISA technique was also used (Premier, Cryptococcal Antigen, Meridian Diagnostic Inc., Cincinnati, Oh, USA). The comparative study of both methods showed that the results obtained were similar in 96.9% of the cases. The capsular antigen was detected in 13 out of 193 (6.7%) patients with less than 300 CD4+ cells/microliters. Cryptococcosis was confirmed mycologically in 3 of these 13 cases (23%) by the isolation of C. neoformans in CSF or blood cultures. Three patients, who had presented negative results of both tests for capsular antigen, suffered disseminated cryptococcosis 4 to 8 months later. The predictive diagnostic value of capsular antigen detection of C. neoformans seems to be low and we believe that it should not be done routinely in asymptomatic HIV-positive persons.

[Value of direct and indirect diagnostic methods in systemic mycoses associated with AIDS]

One hundred and seventeen patients suffering systemic mycosis and AIDS were studied during 5 years in the Muñiz Hospital of Buenos Aires City. Seventy four of them presented cryptococcosis, 39 histoplasmosis and 4 both mycoses. The following specimens were studied for the diagnosis: skin and mucous membrane scrapings, bone marrow aspirations, bronchial secretions, biopsies of different organs, cerebral spinal fluid and blood cultures. Sera were also collected for serologic tests. A total of 203 samples from patients with histoplasmosis were studied, 46.3% of them showed H. capsulatum in microscopic examinations or in cultures, skin scraping was the most sensitive diagnostic method (94.7% of positive results), followed by biopsies (80%) and bone marrow cultures (42.1%). Specific antibodies were detected in 45.4% of the patients with histoplasmosis, using 2 different antigens and 3 types of serologic reactions (complement fixation test, immunodiffusion and counterimmunoelectrophoresis). A total of 413 samples from patients with cryptococcosis were examined, 69% of them confirmed the diagnosis. The mycologic study of CSF was the most sensitive method of study, since it registered positive results in 89.5%, followed by blood cultures (61.2%), skin scrapings (42.9%), and urine cultures (41.7%). Polysaccharyde antigens from C. neoformans in organic fluids were detected in almost all the cases. The aim of this study is to compare all the suitable diagnostic methods which can be used in systemic mycosis associated with AIDS in order to find the most rapid way of diagnosis.

Itraconazole in human histoplasmosis

A non-comparative open trial with itraconazole in progressive forms of human histoplasmosis was carried out. Thirty two patients who completed 6 months of treatment were included; 29 suffered the chronic disseminated form; 2 exhibited a chronic pulmonary histoplasmosis and one patient presented a subacute disseminated form. Thirty patients were males and 2 females; their ages ranged from 37 to 78 years old (average 56.9). The following underlying diseases were registered: hepatopathies: 12 cases; endocrinopathies and steroid therapy: 13 cases; chronic obstructive pulmonary disease: 10 patients; malignancies: 3 cases; long treatment with psychotropic drugs; 2 cases and 1 immunodeficiency of unknown origin. The therapeutic schedule applied was: 100 mg/day, orally, during 2 months, followed by 50 mg/day for another four months. Twenty-nine patients achieved clinical cure, two showed a striking improvement (both had the chronic pulmonary form) and the treatment could not be evaluated in 1 case. A follow-up of longer than a year was registered in 23 cases, one died as a consequence of mesothelioma and another due to renal impairment, and no relapses were observed. A decreasing complement fixation titer (of more than 2-fold) was observed in 19 cases; 8 of 10 patients with negative skin tests turned positive and the erythrocyte sedimentation rate was reduced to more than a half in 24 cases. Concerning side-effects, a mild, transient and asymptomatic rise of the hepatic enzymes was registered in 9 patients. It seems that itraconazole will be the drug of choice in the treatment of human histoplasmosis in immunocompetent patients.

Ketoconazole in the treatment of paracoccidioidomycosis and histoplasmosis

Ketoconazole was given orally to 33 patients with paracoccidioidomycosis and 23 with histoplasmosis. There were 55 men and one woman, and ages ranged from 28 to 67 years. Each patient had either the chronic disseminated or the chronic pulmonary form of disease. The diagnosis was established in 54 patients by culture of Paracoccidioides brasiliensis or Histoplasma capsulatum from lesions and in two patients by the clinical picture and results of serologic tests for histoplasmosis. The initial dosage was 400 mg per day. The dosage was reduced to 200 mg when a cure was achieved. The duration of treatment ranged from two to 18 months. Results of treatment were classified as very good (clinical and serologic cure) in 23 (41%) of the patients; good (clinical cure only) in 28 (50%); fair (partial improvement) in one (2%); and poor (no improvement) in three (5%). The results were not assessable in one patient who did not complete therapy. The three patients who did not respond to treatment had less than or equal to 0.19 microgram of ketoconazole/ml in their blood. The drug was well tolerated, and no side effects were reported.

[Immunodiffusion tests in gel media with the addition of polyethyleneglycol 6000 for the serodiagnosis of mycoses]

Different immunodiffusion techniques with and without the addition of polyetilenglycol 6000 (PEG), were studied to determine its effect on the sensitivity of these reactions. One hundred thirteen sera from patients who suffered or had suffered deep mycoses (paracoccidioidomycosis: 49, histoplasmosis: 25, aspergillosis: 25, candidiasis: 8 and coccidioidomycosis: 6) were examined by the quantitative Ouchterlony's immunodiffusion procedure. Regular medium and media with 2% and 4% PEG were used. Eighty two out of the one hundred thirteen sera were positive for the regular medium and 91 for the medium containing 2% of PEG; furthermore, an increase of 1 or 2 two fold dilutions in the titers was observed in 40% of the sera, for the later media. Twenty one sera from aspergillosis cases were examined by agarose gel immunoelectrophoresis, 80% had more precipitin bands in the medium with 2% of PEG. Thirty four serum samples of patients suffering aspergillosis, paracoccidioidomycosis and histoplasmosis were studied using the agarose electroosmophoresis with the secondary immunodiffusion test. An increase in the number of the anodic bands were observed in 55% while 64% presented more catodic bands, when the PEG medium was used. This results would indicate that the addition of 2% PEG 6000 to the regular medium improves the sensitivity of the immunodiffusion tests for mycoses.

Isolation of plasma membrane glycoprotein from bovine thymocytes

Glycoprotein was isolated from a purified thymocyte membrane preparation by two methods: lithium diiodosalicylate-phenol extraction and hot 75% ethanol extraction. A higher yield of membrane sialic acid was obtained by the latter method. The preparations had similar apparent molecular weights on sodium dodecyl sulfate gel electrophoresis. Both had similar receptor activities against a panel of hemagglutinins, although the 75% ethanol extract was more active on a weight basis. However, there were significant differences in carbohydrate and amino acid compositions of the two thymocyte extracts. The lithium diiodosalicylate-extracted material had much more glucose, ribose, and glycine than the ethanol extract. The glycoprotein preparations from thymocytes were quite distinct from the glycoprotein of bovine erythrocytes in both composition and receptor properties.

[Study of serologic cross reactions between the antigens of Paracoccidioides brasiliensis and Histoplasma capsulatum]

A comparative study of serologic cross-reactions between histoplasmosis and paracoccidioidomycosis was carried out using complement fixation (CF) and agar gel immunodiffusion (ID) tests. Sera from 77 patients with paracoccidioidomycosis, 38 with histoplasmosis and 50 healthy individuals were studied. The Pan American Health Organization microtiter CF test and the Hupper ID technique were employed. The antigens were prepared by the method of Ajello as modified by Negroni. Paracoccidioidin CF test was positive in all patients with paracoccidioidomycosis; 29 of these (37%) presented serologic cross-reaction with histoplasmin. Histoplasmin CF test was positive in all but one of the patients with histoplasmosis and only 4 of them (10%) showed cross-reaction with paracoccidioidin. Positive reactions with the ID test were registered in 74/77 cases of paracoccidiodomycosis, with only one case of cross-reaction (1,3%). The result for the ID test was positive in all but one of the cases of histoplasmosis, with only one cross-reaction with paracoccidiodin (2,7%). The ID test seemed to be much more specific although it could be less sensitive. It was also easier to perform and less expensive than the CF test. Nevertheless the authors urge that the CF test also be carried out whenever posible, since the information obtained is likely to be of more value in follow-up and control of patients.

[Nocardia isolated from the respiratory tract]

Twelve strains of Nocardia isolated from sputa, bronchial washings and pleural fluids, were studied. The classification was based on the following characteristics: a) acid-fastness; 2) ability to disolve crystals of tyrosine and xantine; 3) hydrolysis of casein; 4) growth in dilute gelatin medium (0.4%) and 5) galactose acidification. Direct cultivation of the clinical material in Czapek liquid culture medium without carbon source and containing a paraffin rod (pariffin-bait technic), as well as the routin T.B. sputum digestion and concentration with NaOH solution followed by its cultivation in Loewenstein's medium, were employed for the isolation of Nocardia. The sensitivity of the strains to tuberculostatic drugs was investigated using the Canetti's method, as was the ability to growth in Sabouraud and lactrimel culture media supplemented with 100 mug/ml of rifamycin. Finally the pathogenicity test was carried out by intraperitoneal and intramuscular inoculation in guinea-pigs. All the strains were classified as Nocardia asteroides. Seven starins were isolated from patiens with lung conditions of no nocardial etiology. The diagnosis of nocardiosis of the lung was demonstrated in the remaining five patiens by microscopical observation of Nocardia in clinical specimens, by the repeated cultures obtained from these materials and, finally, by the fact that an improvement of the clinical symptomatology was obtained by sulfa administration.