Future microbiology最新文献

Aim: Animal models of fatal pneumonia caused by Streptococcus pneumoniae (Spn) have not been reliably generated using many strains of less virulent serotypes.Materials & methods: Pulmonary infection of a less virulent Spn serotype1 strain in the immunocompetent mice was established via the intratracheal aerosolization (ITA) route. The survival, local and systemic bacterial spread, pathological changes and inflammatory responses of this model were compared with those of mice challenged via the intratracheal instillation, intranasal instillation and intraperitoneal injection routes.Results: ITA and intratracheal instillation both induced fatal pneumonia; however, ITA resulted in better lung bacterial deposition and distribution, pathological homogeneity and delivery efficiency.Conclusion: ITA is an optimal route for developing animal models of severe pulmonary infections.

Background: Aerococcus urinae and Aerococcus sanguinicola are emerging pathogens linked with urinary tract infections. We present a case series of A. urinae and A. sanguinicola isolates characterizing the spectrum of clinical presentation, microbiological characteristics and antimicrobial sensitivities. Methods: Retrospective chart review was performed on patients who grew positive cultures for A. urinae and A. sanguinicola identified on MALDI-TOF in Saskatchewan from January to June 2023. Demographic and clinical variables, antimicrobial susceptibility and prescription were documented. Results: This cohort (n = 115) had a median age 82 years. A. urinae and A. sanguinicola infections spanned from urinary tract infection (n = 96) to urosepsis (n = 6). These infections were predominantly monomicrobial (73.9%) and were susceptible to ceftriaxone, penicillin G and vancomycin. Antimicrobials were seldom prescribed within the urinary tract infection cohort (31.2%). Conclusion: Untreated A. urinae and A. sanguinicola infections can precipitate into urosepsis. The reported antimicrobial susceptibility for these Aerococcus isolates should be utilized to provide appropriate antimicrobial coverage.

Aim: To determine the efficacy of manuka honey against multidrug-resistant (MDR) and extensively drug-resistant (XDR) clinical strains of Salmonella Typhi. Materials & methods: Clinical isolates were processed using the Bactec blood culture system, identification and antibiogram by Vitek 2 and antibiotic resistance genes through polymerase chain reaction (PCR). Microbroth dilution assays evaluated the antibacterial activity of manuka honey. Results: MDR and XDR-S. Typhi was susceptible to azithromycin. These strains carried the H58, gyrA, gyrB, bla_CTX-M-15 , and bla_TEM-1 genes. At 100% honey, the zone of inhibition for MDR (15-23 mm) and XDR (15-24 mm) strains. 18/50 MDR and 14/50 XDR strains inhibited at 3.125 v/v% killed at 6.25 v/v% concentration respectively. Conclusion: Manuka honey could be an alternative option for treating S. Typhi infections.

Aim: Evaluate the anticandidal effect of Croton heliotropiifolius Kunth essential oil and its interaction with azoles and N-acetylcysteine (NAC) against planktonic cells and biofilms. Materials & methods: Broth microdilution and checkerboard methods were used to evaluate the individual and combined activity with fluconazole and itraconazole (ITRA). The antibiofilm effect of the oil was assessed in 96-well plates alone and combined with ITRA and NAC, and cytotoxicity determined by MTT. Results: The oil inhibited all Candida species growth. The activity was enhanced when associated with ITRA and NAC for planktonic cells and biofilms in formation. The effective concentrations were lower than the toxic ones to V79 cells. Conclusion: C. heliotropiifolius Kunth essential oil is an anticandidal alternative, and can be associated with ITRA and NAC.

Aim: Assessing the visual accuracy of two large language models (LLMs) in microbial classification. Materials & methods: GPT-4o and Gemini 1.5 Pro were evaluated in distinguishing Gram-positive from Gram-negative bacteria and classifying them as cocci or bacilli using 80 Gram stain images from a labeled database. Results: GPT-4o achieved 100% accuracy in identifying simultaneously Gram stain and shape for Clostridium perfringens, Pseudomonas aeruginosa and Staphylococcus aureus. Gemini 1.5 Pro showed more variability for similar bacteria (45, 100 and 95%, respectively). Both LLMs failed to identify both Gram stain and bacterial shape for Neisseria gonorrhoeae. Cumulative accuracy plots indicated that GPT-4o consistently performed equally or better in every identification, except for Neisseria gonorrhoeae's shape. Conclusion: These results suggest that these LLMs in their unprimed state are not ready to be implemented in clinical practice and highlight the need for more research with larger datasets to improve LLMs' effectiveness in clinical microbiology.

Emergomycosis is a dimorphic fungal disease that is typically disseminated and fatal among immunocompromised individuals. In the case report, we presented a patient with intermittent fever, night sweats, coughing and phlegm. Chest computed tomography revealed multiple soft-tissue nodules in both lungs. Routine pathological and microbiological tests did not confirm the diagnosis. Therefore, we conducted pathogen detection using metagenomic next-generation sequencing in bronchoalveolar lavage fluid and identified the pulmonary infection caused by Emergomyces orientalis (Es. orientalis). During the antifungal treatment, the patient experienced renal function damage, and we have attempted various antifungal drugs for treatment. Finally, the patient's condition was brought under control. Therefore, the metagenomic next-generation sequencing pathogen detection was essential.

Aim: This work aims to standardize the three-dimensional hydroxyethyl-alginate-gelatin (HAG) scaffold as a model to evaluate Aspergillus fumigatus biofilm and antifungal treatments. Methods: The scaffold was characterized by physical, rheological and microscopic analyses; the antibiofilm action was evaluated by determination of cfu and metabolic activity. Results: The scaffold was non-toxic showing stability in aqueous media, swelling capacity, elasticity and had homogeneously distributed pores averaging 190 μm. The A. fumigatus biofilm established itself very well on the scaffold and treatment with amphotericin B and voriconazole reduced viable cells and metabolic activity. Conclusion: The HAG scaffold proved to be a model to mimic lung parenchyma, suitable for establishing a 3D biofilm culture of A. fumigatus and evaluating the efficacy of antifungals.

There is an unmet need for effective treatments of Clostridioides difficile infection, an emerging health crisis in the United States. The management of C. difficile infection should include treatment of active infection and a strategy to prevent recurrence. Current gold standard therapy includes oral antibiotics which predispose patients to gut dysbiosis and increase the risk of recurrent infection. Addressing dysbiosis via fecal microbiota transplantation is an active and promising area of research, but studies have lacked standardization which makes outcome and safety data difficult to interpret. Rebyota™, formerly known as RBX2660, is a live biotherapeutic product designed using a standardized protocol and manufacturing process that has been shown to be effective for preventing recurrent C. difficile infection.

Aim: To develop a β-AgVO₃ gel and evaluate its physicochemical stability and antifungal activity against Candida albicans. Materials & methods: The gel was prepared from the minimum inhibitory concentration (MIC) of β-AgVO₃. The physicochemical stability was evaluated by centrifugation, accelerated stability (AS), storage (St), pH, syringability, viscosity and spreadability tests and antifungal activity by the agar diffusion. Results: The MIC was 62.5 μg/ml. After centrifugation, AS and St gels showed physicochemical stability. Lower viscosity and higher spreadability were observed for the higher β-AgVO₃ concentration and the minimum force for extrusion was similar for all groups. Antifungal effect was observed only for the β-AgVO₃ gel with 20xMIC. Conclusion: The β-AgVO₃ gel showed physicochemical stability and antifungal activity.