Replication and long-term persistence of bovine and human strains of Mycobacterium avium subsp. paratuberculosis within Acanthamoeba polyphaga. (9/36)

Free-living protists are ubiquitous in the environment and form a potential reservoir for the persistence of animal and human pathogens. Mycobacterium avium subsp. paratuberculosis is the cause of Johne's disease, a systemic infection accompanied by chronic inflammation of the intestine that affects many animals, including primates. Most humans with Crohn's disease are infected with this chronic enteric pathogen. Subclinical infection with M. avium subsp. paratuberculosis is widespread in domestic livestock. Infected animals excrete large numbers of robust organisms into the environment, but little is known about their ability to replicate and persist in protists. In the present study we fed laboratory cultures of Acanthamoeba polyphaga with bovine and human strains of M. avium subsp. paratuberculosis. Real-time PCR showed that the numbers of the pathogens fell over the first 4 to 8 days and recovered by 12 to 16 days. Encystment of the amoebic cultures after 4 weeks resulted in a 2-log reduction in the level of M. avium subsp. paratuberculosis, which returned to the original level by 24 weeks. Extracts of resection samples of human gut from 39 patients undergoing abdominal surgery were fed to cultures of A. polyphaga. M. avium subsp. paratuberculosis detected by nested IS900 PCR with amplicon sequencing and visualized by IS900 in situ hybridization and auramine-rhodamine staining was found in cultures derived from 13 of the patients and was still present in the cultures after almost 4 years of incubation. Control cultures were negative. M. avium subsp. paratuberculosis has the potential for long-term persistence in environmental protists.  (+info)

Clinical correlates of tuberculosis co-infection in HIV-infected children hospitalized in Peru. (10/36)

INTRODUCTION: In developing countries, tuberculosis (TB) is responsible for almost 250,000 deaths among children yearly. Active TB in children with human immunodeficiency virus (HIV) infection is difficult to diagnose and progresses rapidly to death. The aim of this preliminary study was to investigate the prevalence and clinical correlates of TB-related illness among HIV-infected children admitted to an infectious diseases ward in Peru, a country where TB is highly endemic. METHOD: Forty-seven HIV-infected children admitted for a suspected infectious process in a Peruvian hospital were investigated for evidence of clinical tuberculosis by auramine stain, culture, and polymerase chain reaction (PCR) of clinical specimens. RESULTS: Eight children (17%) had evidence of tuberculosis, including five with positive cultures and three with positive PCR tests only. Weight loss was the only feature associated with a positive test for tuberculosis. Radiological changes were very common in both TB-positive and TB-negative groups and these changes were not useful to identify TB-positive cases. CONCLUSIONS: Weight loss may be used to identify high-risk HIV positive children who require more aggressive evaluation for tuberculosis. Radiological changes were common in both TB-positive and TB-negative groups.  (+info)

A testing scheme for the detection of Mycobacterium avium subsp. paratuberculosis in bovine feces utilizing the ESP para-JEM liquid culture system. (11/36)

A testing scheme for the detection of Mycobacterium avium subsp. paratuberculosis (MAP) in broth cultures of bovine fecal samples carried out in ESP para-JEM System was evaluated. The scheme included acid-fast staining (on signal-positive and signal-negative samples), and confirmation by PCR for 2 MAP-specific targets and subculture of all acid-fast positive PCR-negative samples. Two hundred and fifty bovine fecal samples were evaluated for the presence of MAP using this scheme. Thirty-seven (15%) of 250 fecal samples had a positive culture result when the proposed testing scheme was used, compared to 14 (6%) positive results when using the standard ESP para-JEM protocol (requiring samples to have a positive signal from the system, a positive acid-fast stain, and a positive IS900 PCR result), and 20 (8%) positives when conventional culture was performed on Herrold egg yolk (HEY) media. A preliminary comparison of real-time and conventional PCR on DNA extracted from 15 MAP-positive broth cultures by 3 different protocols suggested that conventional PCR may be a better choice for the confirmation of the presence of MAP in the liquid cultures than real-time PCR.  (+info)

Screening of auramine-stained smears of all fecal samples is a rapid and inexpensive way to increase the detection of coccidial infections. (12/36)

INTRODUCTION: Coccidia are important causes of diarrhea that is often indistinguishable from other forms of community-acquired diarrhea. However, the detection of oocysts is often only performed when explicitly requested, as part of the ova and parasite (O&P) examination. Reappraisal and understanding of the accurate staining characteristics of auramine O (AuO), which stains nucleic acids, may permit the inexpensive and reliable identification of coccidian oocysts at routine workup of all fecal samples. METHODS: AuO-stained smears were prepared from all stool samples received for stool culture in transport medium (SC) and from concentrated stools received for the ova and parasite (O&P) examination. RESULTS: A total of 3732 samples for stool cultures and 3132 samples for O&P examinations were included. Ninety-one samples (1.3%) from 52 patients yielded Coccidia (45 Cryptosporidium spp and 7 Isospora belli). In seven cases oocysts were only detected in samples sent for stool culture in transport medium. The oocysts showed a typical staining pattern and were easy to recognize. The observation of one smear took only around 30seconds, and the reagents and glass slide for one smear did not exceed US$ 0.03. CONCLUSIONS: The screening of all fecal samples with AuO-stained smears is a rapid and inexpensive way to increase the detection of coccidial infections, which in most laboratories can be incorporated into the microscopic workup for mycobacteria.  (+info)

Effects of grinding surgical tissue specimens and smear staining methods on Buruli ulcer microscopic diagnosis. (13/36)


Basis for treatment of tuberculosis among HIV-infected patients in Tanzania: the role of chest x-ray and sputum culture. (14/36)


Use of light-emitting diode fluorescence microscopy to detect acid-fast bacilli in sputum. (15/36)


Cytological diagnosis of pulmonary nocardiosis in an immunocompromised patient. (16/36)

We report a case of pulmonary nocardiosis in an immunosuppressed patient having vasculitis who presented with fever, cough and chest pain. A suspicion of nocardiosis was made on auramine O staining of material procured by CT guided fine needle aspiration cytology right lung. Modified Ziehl-Neelsen staining was useful in confirming the diagnosis. The patient showed remarkable recovery after treatment with co-trimoxazole. Quick identification of this uncommon pathogen in the cytological material using special stains helped in timely diagnosis and successful treatment of the patient.  (+info)