Sensitivity Profile of Fungal Pathogens Responsible for Lower Respiratory Tract Infections in Yaounde

Research Article

J Bacteriol Mycol. 2022; 9(1): 1196.

Sensitivity Profile of Fungal Pathogens Responsible for Lower Respiratory Tract Infections in Yaounde

Claris K¹*, Laure N², Leopold N³, Ekobo S¹ and Hortense G¹

1Faculty of Medicine and Biomedical Sciences, The University of Yaounde 1, Cameroon

2Department of Medical Microbiology, Parasitology, Hematology and Infectious Diseases, National Public Health Laboratory, Yaounde, Cameroon

3Faculty of Sciences, The University of Yaounde 1, Cameroon

*Corresponding author: Killa Claris, Faculty of Medicine and Biomedical Sciences, The University of Yaounde 1, Cameroon

Received: February 08, 2022; Accepted: April 21, 2022; Published: April 28, 2022

Abstract

Background: Infectious diseases of the respiratory tract are known as respiratory tract infections (RTIs). An infection of this type usually is further classified as an upper respiratory tract infection (URI or URTI) or a lower respiratory tract infection (LRI or LRTI). LRIs are the leading cause of death among all infectious diseases. The objective of our study was to bring out the sensitivity profile of fungal pathogens responsible for lower respiratory tract infections in Yaounde

Methods: We carried out a transverse and descriptive study during a 6 month period (February to June 2021), at the Jamot hospital in Yaounde. Included in this study were patients suffering from a lower respiratory tract infection from whom the medical practitioner had requested a sputum or broncho alveolar liquid analysis A macroscopic, microscopic, fungal culture of the sample was carried out and a germ tube test, fungal sensitivity test as well as specie identification using the ID 32 C gallery was carried out on the positive cultures Statistical analysis was carried out using the R version 3.6.1 software. The mean was calculated with the aid of the Kruskal Wallis rank sum test.

Results: 300 patients participated in this study. They had mean age ± standard deviation of 41.59 ± 17.5 years and extremities of 1 and 91years. The male /female ratio was 2:1 Fungal infection was positive in 127 patients (42.33 %), 75 (59%) Candida albicans, 25 (19.68%) Cryptococcus humicola, 10 (7.87%) Candida tropicalis, 6 (4.72%) Candida krusei, 4 (3.14%) Candida famata, 4 (3.14%) Candida sake and 3 (2.36%) Cryptococcus curvatus. As far as antifungigram is concerned, the total drug susceptibility was Nystatine (98.47%), Amphotericine B (86.91%), Miconazole (55.42%), Econazole (52.61%), Ketoconazole (52.57%) and Fluconazole (14.42%).The prevalence of fungal pathogens was 42.33%. Of the 300 patients, 71 had tuberculosis, 24 were HIV positive and 6 were diabetic we had 5 patients with HIV, tuberculosis and fungal co-infection, 16 with HIV and fungal co-infection and 6 with HIV and tuberculosis co-infection.

Conclusion: This study shows a relative high prevalence (42.33%) of the colonization of the respiratory tract by fungal pathogens. The fungal pathogens responsible for lower respiratory tract infections are Candida albicans, Candida tropicalis, Candida krusei, Candida famata, Candida sake, Cryptococcus humicola and Cryptococcus curvatus. The drug of choice is Nystatine and Fluconazole presents a very limited activity. Additional studies should be carried out in other towns in order to better document this issue in Cameroon.

Keywords: Respiratory tract infection; Candida species; Fluconazole; Nystatine; Fungal pathpgens

Abbreviations

AIDS: Acquired Immunodeficiency Syndrome; AJRCCM: American Journal of Respiratory and Critical Care Medicine; BAL: Broncho Alveolar Liquid; CDC: Centers for Disease Control and Prevention; CHROMagarTM: Chromogenic agar; CLSI: Clinical Laboratory Standard Institute; °C: Degree Celsius; GT: Germ Tube; HIV: Human Immunodeficiency Virus; ICU: Intensive Care Unit; KOH: Potassium Hydroxide; LRTI: Lower Respiratory Tract Infection; LRI: Lower Respiratory Infection; mg/L: Milligram per Liter; RSV: Respiratory Syncytial Virus; SAB: Sabouraud; Spp: Species; TB: Tuberculosis; URI: Upper Respiratory Infection; URTI: Upper Respiratory Tract Infection

Introduction

Infectious diseases of the respiratory tract are known as respiratory tract infections (RTIs). An infection of this type usually is further classified as an upper respiratory tract infection (URI or URTI) or a lower respiratory tract infection (LRI or LRTI). LRIs are the leading cause of death among all infectious diseases. The objective of our study was to bring out the sensitivity profile of fungal pathogens responsible for lower respiratory tract infections in Yaounde. The specific objectives were to:

Identify fungal pathogens responsible for lower respiratory tract infections, bring out the sensitivity profile of the different fungal pathogens causing lower respiratory tract infections and determine the prevalence of lower respiratory tract infections caused by fungal pathogens. Candida spp. is the most common cause of intensive care unit (ICU) invasive fungal infections worldwide. The isolation of Candida spp. from respiratory tract secretions of nonimmunocompromised, mechanically ventilated patients varies between 20% and 55%, but it might represent colonization rather than infection [1].

The few studies performed in the 90’s used traditional culture methods [2]. Although culture is still considered to be the gold standard, the method has important disadvantages, such as a longer time to result, the stringent specimen collection and transport condition and the risk of inhibited growth of the pathogens due to previous antibiotic treatment [3,4].

As a consequence, many patients in African healthcare centers remain undiagnosed despite clinical evidence of LRTIs. In critically ill patients Candida spp. are frequently isolated from respiratory tract secretions such as endotracheal aspirates and bronchoalveolar lavages (BAL) and are most often considered as colonizers of the respiratory tract. In contrast, pneumonia due to infection with Candida spp. is rare and is diagnosed by histological demonstration of the yeast in lung tissue with associated inflammation. In spite of this, preemptive antifungal therapy based on isolation of Candida spp. from the respiratory tract is often initiated in critically ill patients. The disadvantages of this approach include increased selective pressure for the development of antimicrobial resistance, potential risks of adverse drug reactions and high treatment costs. On the other hand, immediate administration of appropriate antifungal therapy has been shown to be an important predictor of favorable outcome for patients with invasive fungal infections. Therefore, the development of reliable diagnostic measures for the detection of invasive pulmonary candidiasis is crucial [5]. Candida spp. colonization promotes bacterial pneumonia in animal models.

• Candida spp. colonization could clinically increase the risk for Pseudomonas aeruginosa ventilator-associated pneumonia, prolong mechanical ventilation and stay and worsen outcomes, but to date contrasting data are available.

• Available evidence is not sufficient to support routine antifungal therapy in non-immunocompromised patients.

Candida spp. is part of the normal skin, oropharyngeal, mucosal membranes and upper respiratory tract flora. Candida spp. can reach the lungs through either haematogenous dissemination or aspiration of colonized oropharyngeal or gastric contents [1]. The isolation of Candida spp. from respiratory tract secretions is frequent in non immunocompromised, mechanically ventilated patients. Several studies have reported the presence of Candida spp. in the sputum of 20-55% of patients receiving antibiotics [6,7]. Candida spp. is the most common cause of invasive fungal infections, with an incidence estimated at 72.8 cases per million inhabitants per year [8]. The five main species of Candida spp (C. albicans, C. parapsilosis, C. glabrata, C. tropicalis and C. krusei) are responsible for more than 90% of invasive fungal infections, in both intensive care unit (ICU) and non-ICU patients [9]. Candida pneumonia is a rare lung infection with a high morbidity and mortality, commonly observed as part of a disseminated Candida infection and associated with predisposing clinical circumstances (i.e. long-term antibiotic use, haematologic malignancy or severe immunosuppressive states). The majority of Candida pneumonia cases are secondary to haematological dissemination of Candida spp. [10]. There is no specific clinical or radiological presentation of Candida pneumonia. This aspect of the disease makes the diagnosis difficult to perform. A definitive diagnosis of candida pneumonia is now based on histopathological identification of yeast parenchymal invasion with associated inflammation [11-14].

This study was necessary because there wasn’t any existing data as to the prevalence of fungal pathogens responsible for lower respiratory tract infections in Yaounde [15-20].

Materials and Methods

The aims of our research work were to identify fungal pathogens responsible for lower respiratory tract infections, bring out the sensitivity profile of the different fungal pathogens causing lower respiratory tract infections and determine the prevalence of lower respiratory tract infections caused by fungal pathogens (Table 1 and 2). We carried out a transverse and descriptive study during a 6 month period (February to June 2021), at the Jamot hospital in Yaounde. The study was conducted in Yaounde, the political capital of Cameroon at the Jamot hospital. It is located at Mballa II neighbourhood in Yaounde and specialized in the management and follow up of patients with mental illness. However, the hospital also hosts some other departments apart from the psychiatric department. It has a psychiatric center as well as a pneumology department”. Those with pulmonary diseases (tuberculosis notably) are treated at the pneumology department. General medicine is equally practiced at the hospital center. Samples were collected at the Jamot hospital and transported to the Bacteriology laboratory of the Yaounde teaching hospital for analysis.