Research Article Open Access
Riyaz et al., J Med Microb Diagn 2019, 8:1
DOI: 10.4172/2161-0703.1000294
Research Article Open Access
Journal of
Medical Microbiology & Diagnosis
Volume 8 • Issue 1 • 1000294
J Med Microb Diagn, an open access journal
ISSN: 2161-0703
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ISSN: 2161-0703
*Corresponding author: Nazish Fatima, Department of Microbiology, Jawahar
Lal Nehru Medical College, Aligarh Muslim University, Uttar Pradesh, India, Tel:
+919412174543; E-mail: nazsham28@gmail.com
Received December 28, 2018; Accepted January 27, 2019; Published February
16, 2019
Citation: Riyaz S, Fatima N, Khan HM, Shameem M (2019) Comparison of Various
Laboratory Detection Methods for Diagnosing Pulmonary Aspergillosis. J Med
Microb Diagn 8: 294. doi:10.4172/2161-0703.1000294
Copyright: © 2019 Riyaz S, et al. This is an open-access article distributed under the
terms of the Creative Commons Attribution License, which permits unrestricted use,
distribution, and reproduction in any medium, provided the original author and source
are credited.
Abstract
Aspergillus is a mould which may lead to a variety of infectious, allergic diseases depending on the immune
status or pulmonary structure of the host. Invasive pulmonary aspergillosis occurs primarily in patients with severe
immunodeficiency. Early and rapid diagnosis of systemic fungal infections remain limited, despite intensive efforts
by many investigators. Few clinical guidelines have been previously proposed for either diagnosis or management
of Pulmonary Aspergillosis. The current study was undertaken for comparing various detection methods like
conventional direct microscopy or histopathology, culture methods, immunological (GM ELISA) and molecular
methods (PCR). To identify carcinoma cell types and to categorize Aspergillosis types histopathology was done.
For direct fungal examination, culture, Aspergillus polymerase chain reaction (PCR), and galactomannan (GM)
detection, bronchoalveolar lavage (BAL) fluids were collected. In this study microscopy was found to have low
sensitivity of (70.5%) while culture had highest specificity (97.6%). GM assay showed a sensitivity of 100% and a
specificity of 86.4% whereas PCR has an overall sensitivity of 100% and a specificity of 81.3%. Thus, we suggest
that both BAL PCR and GM ELISA may be beneficial for use in early diagnosis of Aspergillosis, especially those
patients who do not demonstrate radiological signs.
Comparison of Various Laboratory Detection Methods for Diagnosing
Pulmonary Aspergillosis
Sadaf Riyaz
1
, Nazish Fatima
1*
, Harris M Khan
1
and Shameem M
2
1
Department of Microbiology, Jawahar Lal Nehru Medical College, Aligarh Muslim University, Uttar Pradesh, India
2
Department of TB and Respiratory Diseases, Jawahar Lal Nehru Medical College, Aligarh Muslim University, Uttar Pradesh, India
Keywords: Pulmonary Aspergillosis; Diagnosis; PCR; ELISA
Introduction
IPA was first described in 1953 [1]. Due to widespread use of
chemotherapy and immunosuppressive agents, its incidence has
increased over the past two decades [2]. Despite intensive efforts
by many investigators, early and rapid diagnosis of systemic fungal
infections remain limited. Aspergillus spp. when isolated from
respiratory samples does not confirm it as the etiologic pathogen
because airway colonization by Aspergillus spp. is a common feature
in several chronic lung diseases. Only if Aspergillus spp. is repeatedly
isolated and anti- Aspergillus antibodies and/or Aspergillus antigens
in sera are detected, it points towards the etiologic agent of disease
[3]. e only available techniques in most centers to diagnose IA are
conventional direct microscopy, histopathology, and culture methods,
due to the non-availability of galactomannan or beta-glucan tests assay
in developing countries [4].
Bronchoscopy with Bronchoalveolar Lavage (BAL) is generally
helpful in diagnosis of IPA especially in patients with diffuse
lung involvement [5]. Generally, clinical and radiologic signs are
insensitive and non-specific, and the sensitivity of fungal culture
is low [5]. Histopathology plays a good diagnostic role in IPA, but
the invasive nature of tissue biopsy collection discourages its use in
thrombocytopenic patients. us, rapid and more sensitive diagnostic
strategies for fungal infections including detection of antigen or DNA
are being evaluated [6,7].
Galactomannan (GM), double sandwich ELISA (Platelia, Bio-rad)
which incorporates the β1-5 Galactofuranose specific EBA2 monoclonal
antibody as both the acceptor and the detector for Galactomannan,
a polysaccharide cell-wall component that is released by Aspergillus
during growth, has the most promise among the many tests that have
been developed for detection [7]. In the Revised Criteria of EORTC/
MSG for probable invasive Aspergillosis, the Galactomannan antigen
detection has also been included. Although, the detection of nucleic
acid is not included in the criteria, as presently, there are no validated
or standardized methods [8]. While GM cannot identify infecting
Aspergillus species, PCR could be tailored to the species level and may
infer general antifungal susceptibility pattern [5].
Materials and Methods
is study was conducted on patients admitted in the wards or
attending the outpatient department of T.B. and Respiratory Diseases,
Jawaharlal Nehru Medical College and Hospital, AMU, Aligarh,
for a period of one and half year. Study group comprised of patients
suspected of lung carcinoma and chronic lung diseases like interstitial
lung disease, chronic obstructive pulmonary disease etc. Bronchoscopy
was performed for confirmation of clinical diagnosis in around 60
patients. Age and sex matched healthy controls were also included in
the study with no evidence of any chronic lung disease.
A detailed clinical history was recorded for each patient especially
regarding duration of illness, occupation (especially any exposure to
grains), history of smoking/gutka chewing, dietary history and others
like: Signs and symptoms, broad spectrum antibiotics and corticosteroid
therapy.
In a clean sterile vial, Bronchoalveolar lavage (BAL) was collected,
by fiberoptic bronchoscopy. Each BAL specimen was divided in four
parts for direct microscopy, culture, galactomannan and PCR.
Each specimen of bronchoalveolar lavage was subjected to various
laboratory procedures for isolation and identification of Aspergillus spp.