First imported case of Candida auris infection in Milan, Italy: genomic characterisation

PURPOSE

Candida auris, an emerging multidrug-resistant yeast, has been reported worldwide. In Italy, the first case was reported in 2019. We describe the first case of C. auris, imported from Greece, in Milan, using whole genome sequencing to characterise mutations associated with antifungal resistance.

CASE PRESENTATION

On October 2022 an 80-year-old Italian man was hospitalised in Greece. In the absence of clinical improvement, the patient was transferred to our hospital, in Italy, where blood culture resulted positive for C. auris. Despite therapy, the patient died of septic shock. In a phylogenetic analysis the genome was assigned to Clade I with strains from Kenya, United Arab Emirates and India. D1/D2 region resulted identical to a Greek strain, as for many other strains from different World regions, highlighting the diffusion of this strain.

CONCLUSION

Importation of C. auris from abroad has been previously described. We report the first case of C. auris imported into Italy from Greece, according to phylogenetic analysis. This case reinforces the need for monitoring critically ill hospitalised patients also for fungi and addresses the need for the standardisation of susceptibility testing and strategies for diagnosis and therapy.

Traditional Cultures versus Next Generation Sequencing for Suspected Orthopedic Infection: Experience Gained from a Reference Centre

(Background) The diagnosis and the antimicrobial treatment of orthopedic infection are challenging, especially in cases with culture-negative results. New molecular methods, such as next-generation sequencing (NGS), promise to overcome some limitations of the standard culture, such as the detection of difficult-to-grow bacteria. However, data are scarce regarding the impact of molecular techniques in real-life scenarios. (Methods) We included cases of suspected orthopedic infection treated with surgery from May 2021 to September 2023. We combined traditional cultures with NGS. For NGS, we performed a metagenomic analysis of ribosomal 16s, and we queried dedicated taxonomic libraries to identify the species. To avoid false positive results, we set a cut-off of 1000 counts of the percentage of frequency of reads. (Results) We included 49 patients in our study. Our results show the presence of bacteria in 36/49 (73%) and 29/49 (59%) cases studied with NGS and traditional cultures, respectively. The concordance rate was 61%. Among the 19/49 discordant cases, in 11/19 cases, cultures were negative and NGS positive; in 4/19, cultures were positive and NGS negative; and in the remaining 4/19, different species were detected by traditional cultures and NGS. (Conclusions) Difficult-to-grow microorganisms, such as slow-growing anaerobic bacteria, were better detected by NGS compared to traditional culture in our study. However, more data to distinguish between true pathogens and contaminants are needed. NGS can be an additional tool to be used for the diagnosis of orthopedic infections and the choice of appropriate antimicrobial therapy.

Genomic Characterization of an ST1153 PVL-producing Methicillin Resistant Staphylococcus aureus Clinical Isolate in Italy

Methicillin-resistant Staphylococcus aureus (MRSA) clones are rapidly increasing beyond the hospital into the community, livestock farming and environmental settings. An Italian man, a professional diver working in Egypt, was admitted to Infectious Diseases Clinic-ASST Fatebenefratelli Sacco for ulcerative skin lesions. An MRSA strain was isolated from the lesions' purulent exudate and the nasal colonization was also ascertained. The strain, characterized by whole genome sequencing, resulted to be Panton-Valentine Leukocidin (PVL) positive, SCCmecI - spa-type t504, and belonging to the sequence type 1153, sporadically described worldwide.