Interaction between caspofungin or voriconazole and cefoperazone-sulbactam or piperacillin-tazobactam by in vitro and in vivo methods

AADB: A Manually Collected Database for Combinations of Antibiotics With Adjuvants

Antimicrobial resistance is a global public health concern. The lack of innovations in antibiotic development has led to renewed interest in antibiotic adjuvants. However, there is no database to collect antibiotic adjuvants. Herein, we build a comprehensive database named Antibiotic Adjuvant DataBase (AADB) by manually collecting relevant literature. Specifically, AADB includes 3,035 combinations of antibiotics with adjuvants, covering 83 antibiotics, 226 adjuvants, and 325 bacterial strains. AADB provides user-friendly interfaces for searching and downloading. Users can easily obtain these datasets for further analysis. In addition, we also collected related datasets (e.g., chemogenomic and metabolomic data) and proposed a computational strategy to dissect these datasets. As a test case, we identified 10 candidates for minocycline, and 6 of 10 candidates are the known adjuvants that synergize with minocycline to inhibit the growth of E. coli BW25113. We hope that AADB can help users to identify effective antibiotic adjuvants. AADB is freely available at http://www.acdb.plus/AADB.

Coinfection with Hypervirulent Klebsiella pneumoniae and Aspergillus flavus in a Critically Ill Patient with Aspergillus Overlap Syndrome: A Case Report

Pulmonary aspergillosis is generally categorized into three groups: allergic bronchopulmonary aspergillosis, chronic pulmonary aspergillosis and invasive pulmonary aspergillosis. Aspergillus overlap syndromes (AOS) defined as the occurrence of more than one form of aspergillus disease in a single individual is not common. We present a 62-year-old-male patient with tachypnea, hypoxemia and shock after 4 weeks of cough, expectoration and intermittent hemoptysis, and 2 days of hyperpyrexia. Cardiac arrest occurring during tracheal intubation was resuscitated successfully. Laboratory examination showed acute kidney failure and severe myelosuppression with leukopenia and thrombocytopenia. Chest computed tomography (CT) scan showed the cavity with aspergilloma in the right upper lung lobe, a mass of consolidation in the right lower lung lobe and hyperdense shadow bronchiectasis in the left lower lobe. Bronchoscopy showed lots of sputum occluding the opening of the right airway bronchus. Laboratory examination showed significantly increased C-reactive protein (CRP) and procalcitonin concentration, serum (1,3)-β-D-glucan (BDG) and aspergillus immunoglobulin G (IgG) levels were also elevated. The metagenomic next-generation sequencing and sputum cultures revealed Klebsiella pneumoniae and Aspergillus flavus infection. Pulmonary aspergillosis, invasive aspergillosis infection and severe pneumonia were diagnosed. Initial caspofungin and meropenem followed by piperacillin-tazobactam sodium and voriconazole were administrated in combination. Continuous renal replacement therapy and mechanical ventilation were also performed. The patient's condition gradually recovered. Oral antifungal therapy was continued for 1 year after discharge and CT images gradually improved. Coinfections with K. pneumoniae and A. flavus in a patient with AOS will complicate clinical conditions. A search of PubMed showed few reports of similar cases. Clinicians should pay enough attention to the polymicrobial interactions and improve clinical management strategies, especially in critically ill patient with AOS.

Pharmacodynamics of Moxifloxacin, Meropenem, Caspofungin and their Combinations Against In Vitro Polymicrobial Inter-kingdom Biofilms

Biofilms colonize medical devices and are often recalcitrant to antibiotics. Inter-kingdom biofilms, when at least a bacterium and a fungus are co-isolated, increase the likelihood of therapeutic failures. In this work, a three-species in vitro biofilm model including S. aureus, E. coli and C. albicans was used to study the activity of the antibiotics moxifloxacin and meropenem, the antifungal caspofungin, and combinations of them against inter-kingdom biofilms. The culturable cells and total biomass were evaluated to determine the pharmacodynamic parameters of the drug response for the incubation with the drugs alone. The synergic or antagonistic effects (increased/decreased effects) of the combination of drugs were analysed with the highest single agent method. Biofilms were imaged in confocal microscopy after live/dead staining. The drugs had limited activity when used alone against single-, dual- or three-species biofilms. When used in combination, additive effects were observed against single- or dual-species biofilms, and increased effects (synergy) against biomass of three-species biofilms. In addition, the two antibiotics showed different patterns, moxifloxacin being more active when targeting S. aureus and meropenem when targeting E. coli. All these observations were confirmed by confocal microscopy images. Our findings highlight the interest in combining caspofungin with antibiotics against inter-kingdom biofilms.

Secondary Infections After Diagnosis of Severe Radiation Pneumonitis (SRP) Among Patients With Non-small Cell Lung Cancer: Pathogen Distributions, Choice of Empirical Antibiotics, and the Value of Empirical Antifungal Treatment

PURPOSE

This study aimed to assess pathogen distributions and antimicrobial sensitivity characteristics in patients with non-small cell lung cancer (NSCLC) with severe radiation pneumonitis (SRP) and secondary infections.

METHODS AND MATERIALS

Data from 1746 patients with NSCLC and SRP after thoracic radiation therapy from January 2009 to December 2020 were retrospectively analyzed. Pneumonia incidence, causative pathogens, and antibiotic resistance characteristics in patients with secondary lung infections were analyzed. Risk factors associated with mortality were identified through univariate and multivariate analyses. Antifungal drug efficacy and duration-related effects were assessed with Forest plots and receiver operating characteristic curves.

RESULTS

Overall, 44.5% of patients with NSCLC and SRP (777 of 1746 patients) were diagnosed with secondary lung infections. In total, 899 bacterial strains were isolated from these patients, with Acinetobacter baumannii (n = 206; 27%), Klebsiella pneumonia (n = 200; 26.2%), and Pseudomonas aeruginosa (n = 104; 13.6%) being the most common. Carbapenems and cefoperazone-sulbactam resistance rates of 52.7% and 32.2%, 28.8% and 26.4%, and 23.7% and 20.2% were observed for these isolates, respectively. Infection-related deaths occurred in 22.4% of patients with SRP. Independent risk factors for infection-related death included poor performance status scores, inappropriate empirical antimicrobial treatment, bacteria/fungal coinfection, and lack of empirical antifungal treatment. Receiver operating characteristic curves showed that the cutoff value of empirical antifungal treatment duration was 9 (area under the curve: 0.819).

CONCLUSIONS

For patients with SRP and secondary lung infections, appropriate empirical antimicrobial treatment could decrease infection-related mortality, and cefoperazone-sulbactam may be an appropriate antibacterial drug. Empirical antifungal treatment for a minimum of 9 days might contribute to better outcomes. Although this represents a promising treatment approach for patients with SRP and secondary lung infections before antibacterial susceptibility testing, further prospective validation is essential.

Drug repurposing strategies in the development of potential antifungal agents

Abstract

The morbidity and mortality caused by invasive fungal infections are increasing across the globe due to developments in transplant surgery, the use of immunosuppressive agents, and the emergence of drug-resistant fungal strains, which has led to a challenge in terms of treatment due to the limitations of three classes of drugs. Hence, it is imperative to establish effective strategies to identify and design new antifungal drugs. Drug repurposing is a potential way of expanding the application of existing drugs. Recently, various existing drugs have been shown to be useful in the prevention and treatment of invasive fungi. In this review, we summarize the currently used antifungal agents. In addition, the most up-to-date information on the effectiveness of existing drugs with antifungal activity is discussed. Moreover, the antifungal mechanisms of existing drugs are highlighted. These data will provide valuable knowledge to stimulate further investigation and clinical application in this field.

Key points

• Conventional antifungal agents have limitations due to the occurrence of drug-resistant strains.

• Non-antifungal drugs act as antifungal agents in various ways toward different targets.

• Non-antifungal drugs with antifungal activity are demonstrated as effective antifungal strategies.

Anti-Candida activity of existing antibiotics and their derivatives when used alone or in combination with antifungals

Fungal infections are a growing challenge in immunocompromised patients, especially candidiasis. The prolonged use of traditional antifungals to treat Candida infection has caused the emergence of drug resistance, especially fluconazole. Therefore, new therapeutic strategies for Candida infection are warranted. Recently, attention has been paid to the anti-Candida activity of antibiotics and their derivatives. Studies revealed that a series of antibiotics/derivatives displayed potential anti-Candida activity and some of them could significantly increase the susceptibility of antifungals. Interestingly, the derivatives of aminoglycosides were even more active than fluconazole/itraconazole/posaconazole. This article reviews the anti-Candida activities and mechanisms of antibiotics/derivatives used alone or in combination with antifungals. This review will helpfully provide novel insights for overcoming Candida resistance and discovering new antifungals.

Synergistic Activity of the Plant Defensin HsAFP1 and Caspofungin against Candida albicans Biofilms and Planktonic Cultures

Plant defensins are small, cysteine-rich peptides with antifungal activity against a broad range of yeast and fungi. In this study we investigated the antibiofilm activity of a plant defensin from coral bells (Heuchera sanguinea), i.e. HsAFP1. To this end, HsAFP1 was heterologously produced using Pichia pastoris as a host. The recombinant peptide rHsAFP1 showed a similar antifungal activity against the plant pathogen Fusarium culmorum as native HsAFP1 purified from seeds. NMR analysis revealed that rHsAFP1 consists of an α-helix and a triple-stranded antiparallel β-sheet stabilised by four intramolecular disulfide bonds. We found that rHsAFP1 can inhibit growth of the human pathogen Candida albicans as well as prevent C. albicans biofilm formation with a BIC50 (i.e. the minimum rHsAFP1 concentration required to inhibit biofilm formation by 50% as compared to control treatment) of 11.00 ± 1.70 μM. As such, this is the first report of a plant defensin exhibiting inhibitory activity against fungal biofilms. We further analysed the potential of rHsAFP1 to increase the activity of the conventional antimycotics caspofungin and amphotericin B towards C. albicans. Synergistic effects were observed between rHsAFP1 and these compounds against both planktonic C. albicans cells and biofilms. Most notably, concentrations of rHsAFP1 as low as 0.53 μM resulted in a synergistic activity with caspofungin against pre-grown C. albicans biofilms. rHsAFP1 was found non-toxic towards human HepG2 cells up to 40 μM, thereby supporting the lack of a general cytotoxic activity as previously reported for HsAFP1. A structure-function study with 24-mer synthetic peptides spanning the entire HsAFP1 sequence revealed the importance of the γ-core and its adjacent regions for HsAFP1 antibiofilm activity. These findings point towards broad applications of rHsAFP1 and its derivatives in the field of antifungal and antibiofilm drug development.

In vitro synergism observed with azithromycin, clarithromycin, minocycline, or tigecycline in association with antifungal agents against Pythium insidiosum

We describe here the in vitro activities of azithromycin, clarithromycin, minocycline, or tigecycline alone and in combination with amphotericin B, itraconazole, terbinafine, voriconazole, anidulafungin, caspofungin, or micafungin against 30 isolates of the oomycete Pythium insidiosum. The assays were based on the CLSI M38-A2 technique and the checkerboard microdilution method. The main synergisms observed were through the combination of minocycline with amphotericin B (73.33%), itraconazole (70%), and micafungin (70%) and of clarithromycin with micafungin (73.33%).