Candida species in community-acquired pneumonia in patients with chronic aspiration

Microbiological Profile of Patients with Aspiration Pneumonia Identified by Combined Detection Methods

Purpose

Aspiration pneumonia (AP) challenges public health globally. The primary aim of this study was to ascertain the microbiological profile characteristics of patients with AP evaluated by combined detection methods, including conventional microbiological tests (CMTs), chips for complicated infection detection (CCID), and metagenomic next-generation sequencing (mNGS).

Patients and Methods

From June 2021 to March 2022, a total of thirty-nine patients with AP or community-acquired pneumonia with aspiration risk factors (AspRF-CAP) from 3 hospitals were included. Respiratory specimens, including bronchoalveolar lavage fluid (BALF), sputum, and tracheal aspirate, were collected for microorganism detection.

Results

Patients with AP were more inclined to be older, to have a shorter duration from illness onset to admission, to have a higher prevalence of different underlying diseases, particularly diabetes mellitus, chronic heart disease, and cerebrovascular disease, and to have a higher CURB-65 score (all P < 0.05). A total of 213 and 31 strains of microorganisms were detected in patients with AP and AspRF-CAP, respectively. The most common pathogens in AP were Corynebacterium striatum (17/213, 7.98%), Pseudomonas aeruginosa (15/213, 7.04%), Klebsiella pneumoniae (15/213, 7.04%), and Candida albicans (14/213, 6.57%). Besides, the most common pathogens in AspRF-CAP were Candida albicans (5/31, 16.13%), Pseudomonas aeruginosa (3/31, 9.68%) and Klebsiella pneumoniae (3/31, 9.68%). Moreover, Klebsiella pneumoniae (7/67, 10.45%) and Candida glabrata (5/67, 7.46%) were the most common pathogens among the 9 non-survived patients with AP.

Conclusion

The prevalent pathogens detected in cases of AP were Corynebacterium striatum, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Candida albicans. Early combined detection methods for patients with AP enhance the positive detection rate of pathogens and potentially expedites the initiation of appropriate antibiotic therapeutic strategies.

Candida-bacterial cross-kingdom interactions

While the fungus Candida albicans is a common colonizer of healthy humans, it is also responsible for mucosal infections and severe invasive disease. Understanding the mechanisms that allow C. albicans to exist as both a benign commensal and as an invasive pathogen have been the focus of numerous studies, and recent findings indicate an important role for cross-kingdom interactions on C. albicans biology. This review highlights how C. albicans-bacteria interactions influence healthy polymicrobial community structure, host immune responses, microbial pathogenesis, and how dysbiosis may lead to C. albicans infection. Finally, we discuss how cross-kingdom interactions represent an opportunity to identify new antivirulence compounds that target fungal infections.

Invasive Candida pneumonia, in association with Candida esophagitis and gastritis, in a presumably immunocompetent patient

Candida pneumonia remains a difficult diagnosis and is most common in immunocompromised individuals. It has been rarely reported in immunocompetent individuals. We present a case of unsuspected Candida pneumonia associated with Candida esophagitis and gastritis discovered on postmortem examination in a presumably immunocompetent patient. The patient was a 71-year-old male who presented with chest pain and was subsequently found to have a myocardial infarction treated with angioplasty and drug-eluting stent placement. The patient's recovery was complicated by pneumonia refractory to antibiotics, and he went on to experience acute hypoxic respiratory failure, sepsis, disseminated intravascular coagulation (DIC), and ultimately expired. Autopsy revealed evidence of myocardial infarction as well as unsuspected Candida albicans pneumonia, esophagitis, and gastritis. Our case highlights how a presumably immunocompetent individual can develop this infection and how Candida esophagitis and Candida gastritis can be seen in association with Candida pneumonia. Due to the difficulty in diagnosing Candida pneumonia antemortem, autopsies provide a key opportunity to better understand these cases and the factors that may contribute to their development.

An Unusual Case of Severe Pneumonia Caused Due Candida Tropicalis With a Favorable Clinical Response to Antifungals in a Nonimmunocompromised Patient From the Community

Severe pneumonia due to Candida tropicalis infection mainly occurs in immunosuppressed patients or those currently receiving broad-spectrum antibiotics. Herein, we report a case of severe pneumonia caused due to C tropicalis in an elderly patient. A 72-year-old man with a previous history of hypertension, ischemic stroke, and facial paralysis sequelae treated with the botulinic toxin, was admitted to the hospital for dyspnea. Severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) infection was negative. Computed tomography of the chest revealed bilateral consolidation with left predominance. A bronchoalveolar lavage sample was sent to molecular biology, but no microorganisms were detected using a FilmArray respiratory panel. However, mamanocandidas test for candida was 166 pg/mL (positive), and fungal structures were identified by the MALDI-TOF Biotyper mass spectrometry and attributed to C tropicalis. Antifungal therapy was started using caspofungin 75 mg as the initial dose followed by 50 mg daily. After 10 days of treatment, ventilatory weaning was achieved. By day 14, the patient was decannulated from the tracheostomy. Oral antifungal treatment with voriconazole was continued, and he was discharged from intensive care in good clinical condition. Severe pneumonia due to C tropicalis might occur in specific cases, especially in those patients with risk factors, and must thus be considered when approaching such cases.

Candida Pneumonia: An Innocent Bystander or a Silent Killer?

Invasive candidiasis is predominantly seen in immunosuppressed patients and carries a significant mortality. The clinical spectrum of invasive candidiasis encompasses candidemia and disseminated infection (intra-abdominal abscess, osteomyelitis, endophthalmitis, and Candida meningitis). The existence of Candida pneumonia has been largely debated over the years due to its rarity and presence of frequent colonization. Demonstration of Candida species by lung biopsy along with evidence of inflammation is the only way to confirm this entity. The interpretation of Candida in respiratory specimens and the decision to initiate antifungal therapy is controversial due to the lack of clinical evidence. In this mini-review, we discuss the currently available clinical data from the literature on Candida pneumonia and future perspectives regarding the need for antifungal therapy in such patients.