Fungal Isolates of the Respiratory Tract in Symptomatic Patients Hospitalized in Pulmonary Units: A Mycological and Molecular Epidemiologic Study

Life-threatening pulmonary coinfection with Mycobacterium tuberculosis and Aspergillus lentulus in a diabetic patient diagnosed by metagenome next-generation sequencing

BACKGROUND

China has a double burden of diabetes mellitus and tuberculosis. Diabetes mellitus and tuberculosis are both important risk factors for Aspergillus infection. Aspergillus lentulus is an emerging fungal pathogen in China and invasive aspergillosis due to A. lentulus is associated with high mortality.

CASE PRESENTATION

A 79-year-old man was admitted to our hospital, complaining of a 7-day history of fever. Five days before admission, he was diagnosed with pulmonary infection at a local hospital, but his symptoms did not relieve after antibiotic therapy. The patient was diagnosed with diabetes mellitus two months ago. About 20 days ago, he began to present chest tightness and shortness of breath after physical activity. After admission, he developed continuous fever and rapid respiratory deterioration, and finally died after his family abandoned treatment. Pulmonary coinfection with M. tuberculosis and A. lentulus was identified by metagenome next-generation sequencing (mNGS) from bronchoalveolar lavage fluid.

CONCLUSIONS

Clinicians and laboratories should be alert to the emerging A. lentulus infection in China due to its drug-resistance and high mortality. In comparison with conventional methods, mNGS has a great advantage for the diagnosis of mixed pulmonary infection.

Lycosin-II Exhibits Antifungal Activity and Inhibits Dual-Species Biofilm by Candida albicans and Staphylococcus aureus

The increase and dissemination of antimicrobial resistance is a global public health issue. To address this, new antimicrobial agents have been developed. Antimicrobial peptides (AMPs) exhibit a wide range of antimicrobial activities against pathogens, including bacteria and fungi. Lycosin-II, isolated from the venom of the spider Lycosa singoriensis, has shown antibacterial activity by disrupting membranes. However, the mode of action of Lycosin-II and its antifungal activity have not been clearly described. Therefore, we confirmed that Lycosin-II showed antifungal activity against Candida albicans (C. albicans). To investigate the mode of action, membrane-related assays were performed, including an evaluation of C. albicans membrane depolarization and membrane integrity after exposure to Lycosin-II. Our results indicated that Lycosin-II damaged the C. albicans membrane. Additionally, Lycosin-II induced oxidative stress through the generation of reactive oxygen species (ROS) in C. albicans. Moreover, Lycosin-II exhibited an inhibitory effect on dual-species biofilm formation by C. albicans and Staphylococcus aureus (S. aureus), which are the most co-isolated fungi and bacteria. These results revealed that Lycosin-II can be utilized against C. albicans and dual-species strain infections.

Drug Resistance and Biofilm Formation in Candida Species of Vaginal Origin

BACKGROUND

Candida species are normal vaginal flora in healthy women, which can cause vulvovaginal candid-iasis (VVC). The formation of biofilm is a cause of drug resistance in Candida species of vaginal origin. We aimed to specify Candida species cause VVC, detect their biofilm-forming ability, and antifungal susceptibility pattern.

METHODS

Overall 150 vaginal samples were collected from suspected cases of referring to Bahar Hospital of Shahroud, Iran between Jan 2018 and Jan 2019. Samples were cultured on Sabouraud dextrose agar (SDA), Chrome gar Candida and Corn meal agar (CMA). PCR-RFLP was performed to confirm the identification. Bio-film formation of the identified species was measured by the Crystal Violet method. The susceptibility to fluconazole, clotrimazole, and miconazole was determined based on the CLSI document M27-A3.

RESULTS

Of 50 women (33.3%) were suffering from VVC. C.albicans was the predominant species isolated in this study (n=39, 78%) followed by C. glabratia (n=11, 22%). In addition, in 25 (50%) of positive samples, bio-film formation was determined. The mean MIC of fluconazole and clotrimazole for C. albicans was 5.02 μg/mL and 3.92 μg/mL, respectively. Furthermore, the mean MIC related to these drugs for C. glabrata was 12.45 μg / mL and 4.1μg / mL, respectively. The mean diameter of miconazole inhibition zone for C. albicans and C. glabra isolates was 25.13 mm and 24.5mm, respectively and all of them were susceptible to this drug.

CONCLUSION

C.albicans was the predominant Candida species isolated from patients with VVC and also was the predominant biofilm producer species.

Fungal and bacterial co-infections of the respiratory tract among patients with COVID-19 hospitalized in intensive care units

Backgrounds

The pandemic of COVID-19 has created a global public health crisis. ICU patients with COVID-19 are prone to infections of bacterial and/or fungal origins due to several risk factors. Consequently, the current study was conducted to evaluate the frequency, demographic characteristics, underlying conditions, and etiologic agents of fungal and bacterial co-infections of the respiratory tract among ICU patients with COVID-19 in Iran.

Materials and methods

From May to October 2020, sputa and endotracheal aspirates were collected from ICU patients hospitalized with COVID-19 who also were suspected of bacterial and/or fungal co-infections according to inclusion criteria. The etiologic agents of bacterial co-infections were identified using the Vitek 2 identification method. For fungal identification, all samples were analyzed by direct microscopy using KOH 10% and culture. Furthermore, all isolates were subjected to sequencing method.

Results

A total of 73 lung specimens were obtained from patients who met the inclusion criteria. Of these, in 15 cases (20.54%) fungal and/or bacterial co-infections were confirmed. Males were more infected (73.33%) and all of them were between 49 and 79 years. Candida albicans (n = 8, 61.53%) and Klebsiella pneumoniae (n = 5, 38.46%) were the most frequent etiologic agents related to fungal and bacterial co-infections, respectively. Pneumonia (n = 15, 100%) and diabetes mellitus (n = 8, 53.33%) were documented as the most prevalent underlying conditions. In the current study, 3 out of 15 patients (20%) died.

Conclusion

The frequency of bacterial co-infections of the respiratory tract in ICU patients hospitalized with COVID-19 was relatively high. According to the results, one of the causes of death of these patients could be a secondary infection.

Mycetoma due to Aspergillus flavus in a diabetic patient: Case report and literature review

Diabetes mellitus patients are prone to cutaneous and subcutaneous fungal infections due to pathogenic fungi, including dermatophytes, Mucorales, Candida, Aspergillus, and Fusarium species. Here, we report a case of A. flavus mycetoma confirmed by isolation and molecular identification. The case was a 38-year-old male farmer with a seven-year history of type 2 diabetes mellitus, living in Khuzestan, southwest of Iran. The patient presented with a right foot swelling associated with a nodule and multiple discharging sinuses following trauma sustained on the foot while working barefoot on the rice farm, a year ago. The nodule appeared at the site of the trauma two months after the injury. The initial diagnosis was based on direct microscopic examination of lesions scraping using 20% potassium hydroxide and radiology. Molecular analysis confirmed the isolates to be A. flavus. In vitro susceptibility of the isolate to voriconazole, posaconazole, caspofungin, itraconazole, and amphotericin B was determined. Treatment with voriconazole (200 mg twice daily) stopped the purulent discharge, reduced the swelling, and improved the clinical condition within two months. The study emphasizes the importance of wearing footwear to prevent skin trauma as the main risk factor of patient involvement.

Antifungal and antitoxin effects of propolis and its nanoemulsion formulation against Aspergillus flavus isolated from human sputum and milk powder samples

Background and Aim:

Aspergillus flavus causes human and animal diseases through either inhalation of fungal spores or ingestion of mycotoxins as aflatoxins produced in human and animal feed as secondary metabolites. This study was aimed to detect the incidence of A. flavus and its aflatoxins in human sputum and milk powder samples and explore the efficacy of pure propolis (PP) and propolis nanoemulsion (PNE) as natural decontaminants against fungal growth and its released aflatoxins.

Materials and Methods:

A. flavus was isolated by mycological culture and identified macroscopically and microscopically. Coconut agar medium and thin-layer chromatography (TLC) were used to qualitatively detect aflatoxins in the isolated strains. Toxins were extracted from toxigenic strains by the fast extraction technique. The quantitative detection of toxin types was explored by high-performance liquid chromatography (HPLC). PNE was prepared by a novel method using natural components and characterized by Fourier-transform infrared spectroscopy, Zetasizer, and transmission electron microscopy. The effects of PP and PNE on A. flavus growth and its toxin were determined by the well-diffusion method and HPLC.

Results:

The mycological culture showed that 30.9% and 29.2% of sputum and milk powder samples were positive for A. flavus, respectively. TLC confirmed the production of 61.8% and 63.2% aflatoxin by the isolated strains in sputum and milk powder, respectively. PP and PNE showed antifungal activity on A. flavus growth with mean±standard error (SE) inhibition zones of 27.55±3.98 and 39.133±5.32 mm, respectively. HPLC revealed positive contamination of toxin extracts with AFB1, AFB2, and AFG2 at 0.57±0.026, 0.28±0.043, and 0.1±0.05 mg/L, respectively. After treatment with PP and PNE, a significant decrease in AFB1, AFB2, and AFG2 concentrations was observed.

Conclusion:

This study suggested using propolis and its nanoformulation as antifungal and antitoxins in human medicine and the food industry to increase the food safety level and stop food spoilage.

The mycological and molecular study of Pneumocystis jiroveci pneumonia among HIV and non-HIV immunocompromised patients hospitalized in pulmonary units in Guilan, Northern Iran

Background and Objectives

Pneumocystis jirovecii pneumonia (PJP) is a serious infection that usually affects those with a weak immune system. Since the prevalence of this infection in Iran and in the world is not clearly defined, the present study aimed to evaluate the incidence, clinical spectrum, and demographic characteristics of PJP among HIV and non-HIV immunocompromised patients.

Materials and Methods

Bronchoalveolar Lavage (BAL) specimens were obtained from 3 groups of immunocompromised patients, including acquired immunodeficiency syndrome (AIDS) patients, diabetic patients, and patients receiving immunosuppressive therapies. All were hospitalized in pulmonary units. The specimens were examined using microscopic methods (Giemsa and calcofluor white staining) and the nested-PCR technique based on mtLSU-rRNA gene.

Results

A total of 120 BAL samples were collected. From 12.5% (5 from 40) of HIV-infected patients, 5% (2 from 40) of patients receiving immunosuppressive therapies, and 2.5% (1 from 40) of diabetic patients Pneumocystis jiroveci was isolated. There was not any association between the prevalence of PJP and the patient's gender (p= 0.557) and age (p= 0.681). Fever and dyspnea (n=7, 87.5%), nonproductive cough and abnormal auscultation sound (n=5, 62.5%), and also chills and weight loss (n=2, 25%) were the documented clinical symptoms of PJP. Also, the results showed that none of the samples had positive results for P. jiroveci with microscopic tests while using the nested-PCR method 8 samples had positive results.

Conclusion

Since PJP often causes symptoms that are similar to other illnesses, such as the flu or tuberculosis, clinical and laboratory findings should be used simultaneously for making the final decision on drug administration.

The relationship between biofilm formation and mortality in patients with Candida tropicalis candidemia

BACKGROUND

Biofilm formation by Candida species is an influential virulence factor in candidemia pathogenesis. We investigated the relationship between biofilm formation of Candida tropicalis isolates with the clinical characteristics and mortality outcomes in patients with candidemia.

MATERIALS AND METHODS

Thirty-nine C. tropicalis isolates were recovered from patients with candidemia admitted to two university hospitals in Tehran, Iran. Biofilm mass and metabolic activity of C. tropicalis biofilms were assessed in vitro with two colorimetric methods. The sessile minimum inhibitory concentrations (SMICs) were evaluated in vitro by treating preformed biofilms with diluted concentrations of azoles according to CLSI-M27 A3/S4 protocol, followed by metabolic activity quantification. The expressions of ERG11, UPC2, MDR1, and CDR1 genes were also evaluated.

RESULTS

All C. tropicalis isolates produced biofilm. Respectively, higher <7-day and ≥7-day mortality rates were found among cases with high metabolic activity (46.7% vs. 13%, P = 0.03) and high biofilm mass (31.8% vs. 0, P = 0.029). Sessile cells had high resistance to fluconazole, voriconazole, and itraconazole. The azole minimum inhibitory concentrations (MICs) of C. tropicalis sessile were significantly greater than the planktonic minimum inhibitory concentrations (PMICs). In fluconazole-treated biofilms, the expression of ERG11 and UPC2 genes was increased.

CONCLUSION

Our findings highlight the importance of C. tropicalis biofilm formation as an important factor in candidemia pathogenesis and the clinical outcome of patients with candidemia.

The Prevalence, Etiological Agents, Clinical Features, Treatment, and Diagnosis of HIV-Associated Oral Candidiasis in Pediatrics Across the World: A Systematic Review and Meta-Analysis

In HIV-infected pediatrics, oral candidiasis (OC) is a global issue of concern due to its association with dysphagia, malnutrition, and mortality. The present systematic review and meta-analysis are the first to determine the prevalence of OC in HIV-infected pediatrics worldwide. We searched international (PubMed, Web of Science, Scopus, and Embase) databases for studies published between January 2000 to May 2020 reporting the epidemiologic features of OC in HIV-infected pediatrics. Inclusion and exclusion criteria were defined to select eligible studies. Data were extracted and presented according to PRISMA guidelines. The results of the meta-analysis were visualized as a forest plot. Heterogeneity was also analyzed using the I ², and τ² statistics. The publication bias was evaluated using Egger test. The literature search revealed 1926 studies, of which 34 studies met the eligibility criteria, consisting of 4,474 HIV-infected pediatrics from 12 different countries. The overall prevalence of OC among HIV-infected pediatrics was 23.9% (95% CI 17.3-32.0%), and Candida albicans was the most prevalent etiologic agent. Pseudomembranous candidiasis was the predominant clinical manifestation in HIV-infected pediatrics suffering from OC. Thirty articles involving 4,051 individuals provided data on HIV treatment status. Among the 4,051 individuals, 468 (11.53%) did not receive HIV treatment. The data from 11 articles demonstrated that HIV treatment was significantly associated with a reduction in oral Candida colonization or infection. In contrast, others showed the opposite relationship or did not report any statistical data. A high level of I ² (I ² = 96%, P < 0.01) and τ² (τ² = 1.36, P < 0.01) was obtained among studies, which provides evidence of notable heterogeneity between studies. OC is approximately frequent in HIV-positive children. Therefore, efforts should be made to teach dental and non-dental clinicians who care for HIV-infected pediatrics to diagnose and treat this infection.