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M9490337.TXT
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1994-09-19
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Document 0337
DOCN M9490337
TI Laboratory diagnosis and occurrence of Pneumocystis carinii.
DT 9411
AU Elvin K; Microbiology and Tumorbiology Center, Karolinska Institute,;
Stockholm, Sweden.
SO Scand J Infect Dis Suppl. 1994;94:1-34. Unique Identifier : AIDSLINE
MED/94337185
AB Pneumocystis carinii is an opportunistic pathogen causing life
threatening pneumonia (PCP) in immunosuppressed patients and
particularly among AIDS patients. Whether the infection results from
reactivation or reinfection is debated. Since methods for in vitro
cultivation still are not successful, the diagnosis is dependent on
direct demonstration of the organism in respiratory specimen. In this
thesis laboratory diagnostic methods in terms of staining, sampling,
antibody detection and DNA amplification are evaluated. Furthermore, the
occurrence of the organism in the Western world versus Africa, and in
symptomatic and asymptomatic HIV infected patients is studied and
discussed. The use of a monoclonal antibody (MAb), 3F6 in an indirect
immunofluorescence assay (IFL) was compared to the two most commonly
used chemical stains, silver methenamine and toluidine blue. The IFL
method detected both cyst and trophozoite stages of P. carinii and was
more sensitive than the chemical stains when applied to sputum samples.
Among commercialised MAbs for P. carinii detection by IFL, only the
indirect tests were readily applicable to ethanol treated HIV
inactivated samples. In contrast to the MAb 3F6, (Dakopatts), the MAb
from Northumbria stained only a selection of the cysts and no
trophozoites. The relative sensitivity of IFL in detecting the organism
in sputum samples compared to bronchoalveolar lavage (BAL) samples was
estimated to be at least 70%. The polymerase chain reaction (PCR), which
can amplify specific DNA fragments, was used for the demonstration of P.
carinii in sputum and BAL specimens. The PCR was shown to be specific
and more sensitive than IFL. However, P. carinii DNA was found in a few
patients without clinical evidence of present, past or future PCP. Thus
the possibility of PCR to detect colonization must be considered.
Detection of antibodies to P. carinii by indirect IFL was studied in HIV
versus non-HIV patients. A titer rise was seen in 45% of non-HIV
patients versus only 3% in HIV patients during a PCP episode. No humoral
response was seen in AIDS patients, whereas the serology did support the
clinical PCP diagnosis in a proportion of the otherwise immunosuppressed
patients. Serology may however not be of help in the acute setting. In
the beginning of 1988 PCP had not yet been reported from Central Africa
where the AIDS epidemic by then was growing fast. The occurrence of P.
carinii in Central Africa was evaluated by a comparative study on
induced sputum samples from HIV infected patients with pulmonary
infection in Stockholm, Sweden and Lusaka, Zambia.(ABSTRACT TRUNCATED AT
400 WORDS)
DE Acquired Immunodeficiency Syndrome/BLOOD/*MICROBIOLOGY Adolescence
Adult Antibodies, Fungal/BLOOD Bronchoalveolar Lavage
Fluid/MICROBIOLOGY Comparative Study Female Fluorescent Antibody
Technique Human HIV Infections/BLOOD/*MICROBIOLOGY Male Methenamine
Pneumocystis carinii/*ISOLATION & PURIF Pneumonia, Pneumocystis
carinii/BLOOD/EPIDEMIOLOGY/*MICROBIOLOGY Polymerase Chain Reaction
Prospective Studies Sensitivity and Specificity Sputum/MICROBIOLOGY
Support, Non-U.S. Gov't Sweden/EPIDEMIOLOGY Time Factors Tolonium
Chloride Zambia/EPIDEMIOLOGY JOURNAL ARTICLE
SOURCE: National Library of Medicine. NOTICE: This material may be
protected by Copyright Law (Title 17, U.S.Code).