Immunosupression, flagellated protozoa in the human airways and metronidazole: observations on the state of the art

Geospatial Analysis and Molecular Epidemiologic Study of Emerging Pulmonary Lophomoniasis in Iran: A National Registry-Based Study

Introduction

Bronchopulmonary lophomoniasis (BPL) is a protozoan pulmonary disease that has been reported sporadically, but its incidence has been increasing. However, the epidemiology and risk factors of the disease have not been clearly identified. The current study aims to identify BPL cases molecularly and assess the demographic and some environmental factors for the first time on the prevalence of BPL as a national registry-based study in Iran. Methodology. The study tested 960 patients with lower respiratory tract symptoms whose bronchoalveolar lavage samples were submitted from seven provinces of Iran to the Iranian National Registry Center for Lophomoniasis. They were tested for BPL by a newly developed polymerase chain reaction test. The study assessed the association of Normalized difference vegetation index (NDVI), digital elevation model (DEM), and geographic latitude as environmental factors and sex and age as demographic factors on the prevalence of BPL. Geospatial information systems methods and chi-squared and Pearson's correlation tests were used for the assessment of geographical and environmental factor effects and statistical analysis, respectively.

Results

Of the 960 patients, 218 (22.7%) tested positive for BPL; the highest and lowest prevalence rates were reported from the south and northeast of Iran, respectively. The study found a correlation between geographic latitude and age with BPL prevalence, but no association was found for gender, NDVI, or DEM. Most patients were over 40 years old, and the rate of disease was higher in southern latitudes.

Conclusion

Age and geographical latitude were found to be risk factors for BPL. More exposure to dust and/or chronic pulmonary problems may explain the higher prevalence of the disease in older adults. Higher rates of BPL in lower latitudes may be due to warmer weather and longer days, which can confine individual activities indoors and result in more contact with domestic insects and infected dust.

Effective Treatment of Chronic Cough with Tinidazole as the Newest Antiprotozoa against Lophomonas blattarum

Background

Chronic cough is a common problem in the setting of family physicians. Recently, Lophomonas blattarum was considered a cause of respiratory symptoms in children and adults.

Objective

This study is aimed at determining the effect of antiprotozoal treatment of Lophomonas in patients with a chronic cough in Mashhad during 2020-2021.

Materials and Methods

This study was a randomized clinical trial. In this study, 60 patients with chronic cough and unremarkable imaging findings, who were unresponsive to three steps of standard treatment, were randomly assigned to the treatment, with 2 weeks of tinidazole and placebo. The tinidazole and placebo were prepared in a completely identical shape, and a random assignment was performed by a third party. The primary outcome was a complete resolution of cough. A follow-up of treatment was performed. Data were analyzed using the SPSS software version 25.

Results

The basic demographic results showed no significant differences of sex and age between two groups. The results of this study showed a complete resolution of all respiratory symptoms in 40% (12), a complete improvement of cough in 40% (12), and a complete resolution of dyspnea in 50% (10) of the tinidazole group. The remaining showed significant improvement in the severity of cough and dyspnea. Postnasal drip, sputum, body temperature, and airway hyperresponsiveness were improved significantly. After tinidazole treatment, laboratory assessment of bronchial lavage and sputum revealed that 86 percent of smears were converted to negative.

Conclusion

Tinidazole effectively resolved the chronic cough and most of the respiratory symptoms. Lophomonas blattarum is a potential mechanism for chronic cough.

Morphological and Molecular Identification of Emerged Lophomonas blattarum Infection in Mazandaran Province, Northern Iran: First Registry-Based Study

BACKGROUND

In the last decade, several cases of bronchopulmonary lophomoniasis (BPL) have been recorded. Little information is available about epidemiological aspects on Lophomonas infection among BPL patients. The present study was aimed to investigate the prevalence of Lophomonas spp. infection in patients who were referred to the Iranian National Registry Center for Lophomoniasis (INRCL), using morphological and molecular tests.

SUBJECTS AND METHODS

We examined patients enrolled in the INRCL from 2017 to 2019 at the Mazandaran University of Medical Sciences, northern Iran. All bronchoalveolar lavage fluid (BALF) and two nasal discharges of the patients were examined by both microscopic and small-subunit ribosomal RNA (SSU rRNA) PCR methods. To confirm the species of Lophomonas, two positive samples were sequenced.

RESULTS

In this study, 321 specimens (including 319 BALF and 2 nasal discharges) were microscopically examined. Lophomonas spp. was found in 45(14%) (n = 44 BAL; n = 1 nasal discharge). The mean age of infected patients was 54.9 ± 17.1 years. The following morphological characteristics were observed in both fresh and Papanicolaou-stained smears to identify Lophomonas spp. All microscopically positive specimens were confirmed with genus-specific PCR technique. The obtained sequences were deposited in Gen Bank under the accession numbers (MN243135-36). The BLAST analysis of our two sequences with the only available sequence in the Gen Bank of the Thailand strain of L. blattarum, showed identity of 99-100% and 98.51%, respectively.

CONCLUSION

To the best of our knowledge, this is the first registry-based study regarding lophomoniasis worldwide. According to our study, the conventional PCR test is an available and reliable tool for confirming the Lophomonas parasite in clinical samples. Moreover, the results confirmed that L. blattarum is circulating at least in our region.

Bronchopulmonary Disease Caused by Flagellated Protozoa Infection in 15 Chinese Children

BACKGROUND

Bronchopulmonary disease caused by flagellated protozoa infection (BPFP) is thought to be rare in children but may be an emerging or underestimated disease, especially in developing countries.

METHODS

In this study, we retrospectively reviewed records of 15 patients who were presented with a cough, wheezing or bronchopulmonary disease of unknown causes during admission, and patients who were finally diagnosed with BPFP from January 2014 to January 2015 were enrolled. Protozoa were observed in bronchoalveolar lavage fluid by light microscopy.

RESULTS

A total of 15 pediatric cases (11 male and 4 female individuals, from 1 year 8 months to 12 years 1 month of age) with flagellated protozoa infection diagnosed by light microscopy were recruited. The course of the disease at the time of diagnosis was from 10 days to 11 months. Patients presented with a fever (N = 9), cough (N = 11), wheezing (N = 5) and chest pain (N = 5). Laboratory data showed elevated peripheral blood leucocytes (N = 6), eosinophilic granulocytes (N = 3), C-reactive protein (N = 5) and immunoglobulin E (N = 3). Bronchoscopy revealed a mucus plug (N = 3) and bronchiectasis (N = 1). Lung computed tomography results indicated ground-glass opacification (N = 2), atelectasis (N = 3), bronchiectasis (N = 1), bronchial wall thickening (N = 3) or nodular opacity (N = 6, including 1 case of pulmonary embolism). All children responded to metronidazole for a 2- to 5-week treatment period.

CONCLUSIONS

Patients with BPFP often have a chronic or recurrent course and present with recurrent fever, cough, wheezing and chest pain. Chest imaging may reveal ground-glass opacification, atelectasis, bronchiectasis or nodular opacity (including pulmonary embolism). BPFP responds favorably to metronidazole treatment.

Identification criteria of the rare multi-flagellate Lophomonas blattarum: comparison of different staining techniques

Bronchopulmonary lophomoniasis (BPL) is an emerging disease of potential importance. BPL is presented by non-specific clinical picture and is usually accompanied by immunosuppression. Culture of Lophomonas blattarum is difficult and its molecular diagnosis has not yet been developed. Therefore, microscopic examination of respiratory samples, e.g., bronchoalveolar lavage (BAL) or sputum, is the mainstay of BPL diagnosis. Creola bodies and ciliocytophthoria are two forms of bronchial cells which occur in chest diseases with non-specific clinical picture like that of BPL. Both forms could be misrecognized as multi-flagellates because of their motile cilia in the wet mounts and due to shape variability of L. blattarum in stained smears. The aim of the study is to compare different staining techniques for visualizing L. blattarum to improve the recognition and diagnosis of BPL, to distinguish respiratory epithelial cells from L. blattarum and to decide which stain is recommended in suspected cases of BPL. BAL samples from patients which contain L. blattarum, creola bodies, and ciliocytophthoria were collected then wet mounts were examined. The BAL samples were also stained by Papanicolaou (PAP), Giemsa, hematoxylin and eosin (H & E), trichrome, Gram, and Diff-Quik (DQ) stains. The different staining techniques were compared regarding the stain quality. In wet mounts, the ciliary movement was coordinate and synchronous while the flagellar movement was wavy and leaded to active swimming of L. blattarum. In stained slides, bronchial cells were characterized by the presence of basal nucleus and the terminal bar from which the cilia arise. Trichrome was the best stain in demonstration of cellular details of L. blattarum. H & E, PAP, and Giemsa stains showed good quality of stains. Gram and DQ stains showed only pale hues of L. blattarum. We recommended adding Wheatley's trichrome staining to the differential diagnosis workup of cases of non-specific chest infections, especially when BPL is suspected, to avoid overdiagnosis or underdiagnosis of it.

Putative bronchopulmonary flagellated protozoa in immunosuppressed patients

Flagellated protozoa that cause bronchopulmonary symptoms in humans are commonly neglected. These protozoal forms which were presumed to be “flagellated protozoa” have been previously identified in immunosuppressed patients in a number of studies, but have not been certainly classified so far. Since no human cases of bronchopulmonary flagellated protozoa were reported from Turkey, we aimed to investigate these putative protozoa in immunosuppressed patients who are particularly at risk of infectious diseases. Bronchoalveolar lavage fluid samples of 110 immunosuppressed adult patients who were admitted to the Department of Chest Diseases, Hafsa Sultan Hospital of Celal Bayar University, Manisa, Turkey, were examined in terms of parasites by light microscopy. Flagellated protozoal forms were detected in nine (8.2%) of 110 cases. Metronidazole (500 mg b.i.d. for 30 days) was given to all positive cases and a second bronchoscopy was performed at the end of the treatment, which revealed no parasites. In conclusion, immunosuppressed patients with bronchopulmonary symptoms should attentively be examined with regard to flagellated protozoa which can easily be misidentified as epithelial cells.

Lophomonas blattarum and bronchopulmonary disease

The natural habitat of the multiflagellate protozoon Lophomonas blattarum is as an endocommensal in the hindgut of insects such as cockroaches. However, it also causes bronchopulmonary disease in humans. The aim of this paper was to review the literature on this organism in the context of respiratory disease. The biology epidemiology, route of transmission, pathogenic mechanisms and diagnosis methods are also described. A total of 61 cases were identified in the literature. The majority of these reports were from China, with some cases from Peru and Spain. Most cases were adult males, although paediatric cases were reported in Peru. Clinical presentation was non-specific, including symptoms such as fever, cough and breathless. Antiprotozoal therapy was generally effective.

Clinical and immunological characteristics associated with the presence of protozoa in sputum smears

The objective of this study is to assess the relationship between protozoa in spontaneously expectorated sputum samples and a range of clinical and immunological variables. Clinical details including age, gender, smoking status, and use of oral or inhaled steroids were recorded for a cohort of 199 patients whose spontaneously expectorated sputum samples were submitted to a Cytology Laboratory in Spain between January 2005 and December 2006. Slides were scanned for protozoa under light microscopy and scanned for monocytes/small macrophages highlighted by immunocytochemistry (CD68 monoclonal antibody). One hundred ninety-one patients provided adequate sputum samples, of whom 70 had protozoa in their sputum. There was a strong relationship between the presence of protozoa and monocytes/small macrophages identified under light microscopy (P < 0.001). A binary logistic regression model also indicated a relationship between protozoa and both smoking status and steroid use. The diagnoses in those with protozoa included infection (including tuberculosis), chronic obstructive pulmonary disease (COPD), lung fibrosis, asthma, chronic liver disease, immunosuppression, cancer, pancreatic or renal disease, heart failure, and AIDS. The identified association between protozoa and monocytes/small macrophages in sputum suggests an immune response and warrants further investigation to clarify whether or not these organisms have any pathological significance in this wide range of conditions.

Association between protozoa in sputum and asthma: a case-control study

BACKGROUND

Atypical infectious agents have been proposed as potential contributors to asthma. A novel set of morphological and staining criteria permit the identification of flagellated protozoa in sputum. This case-control study was designed to use this novel method and to assess: (1) are protozoa more common in asthmatics than in non-asthmatics; (2) is the presence of protozoa associated with the use of steroid inhalers; and (3) is the presence of protozoa associated with living in damp housing?

METHODS

Induced sputum samples were collected from asthma patients and local non-atopic, non-smoking controls. Questionnaires assessed asthma severity and housing conditions. Sputum was examined for flagellated protozoa using a previously described staining technique.

RESULTS

96 participants were recruited for this study; 54 asthma patients and 42 controls, age range 21-62 years, 70% female participants. Limiting results to those who were clearly positive or negative for flagellated protozoa, 66.7% (20/30) of asthmatics and 30.8% (4/13) of controls had protozoa (p = 0.046). Among the asthma patients, prevalence of protozoa was not significantly different between those who had (10/18), and those who had not (10/12), used steroid inhaler in the preceding two weeks (p = 0.11). Similarly, the prevalence of protozoa was not significantly different between those who did (6/11) and those who did not (18/32), live in damp homes (p = 0.92).

CONCLUSIONS

This case-control study demonstrates an association between flagellated protozoa in sputum and asthma. It is now necessary to confirm and characterise the protozoa using genetic techniques based on 18S ribosomal RNA. Once tis is established it would be worthwhile to determine if asthma symptoms improve when treated by anti-protozoal agents.