Candida auris is an emerging healthcare-associated infection that can easily cause dissemination in hospitals through colonizing the skin and contaminating environmental surfaces, especially in Intensive Care Units (ICU). Difficulties with identification of this organism, uncertainty about routes of transmission and antifungals resistance have impacted significantly outbreak detection and management. Here, we describe our experience with colonization/infection of C. auris among critically ill patients, admitted to a referral ICU of a University Hospital, in a transitional period (July 2021–March 2022) between management of non-COVID-19 and COVID-19 patients due to the reconversion of the ICU between two waves. A total of 8 patients presented colonization from C. auris, and two of them developed invasive infection from C. auris. The fungal pathogen was cultured from different sites: the skin (7 isolates), urine (2), respiratory tract (1), blood (1). The median time from admission to first detection is 24 days with 100% of patients requiring mechanical ventilation. All 8 patients received broad-spectrum antibiotic therapy for bacterial infections before identification of C. auris; 62.5% of the patients had prior antifungal exposure; 87.5% received steroids; 37.5% patients used immunomodulatory; and 75% had severe COVID-19 illness prior to C. auris identification. Only two cases (25%) were treated with antifungals as C. auris infections (1 patient for suspected UTI; 1 patient with candidemia). Infection control measures, including rapid microbiological identification, contact isolation, screening of contacts, antisepsis of colonized patients, dedicated equipment, cleaning and disinfection of the environment and subsequent follow-up sampling, remain essential in critically ill patients. Our experience highlights the importance of establishing a multidisciplinary model and bundling of practices for preventing C. auris’ spread.

Prolonged SARS-CoV-2 infections are widely described in immunosuppressed patients, but safe and effective treatment strategies are lacking. We aimed to outline our approach to treating persistent COVID-19 in patients with immunosuppression from different causes. In this case series, we retrospectively enrolled all immunosuppressed patients with persistent SARS-CoV-2 infections treated at our centers between March 2022 and February 2023. Patients received different sequential or combination regimens, including antivirals (remdesivir, nirmatrelvir/ritonavir, or molnupiravir) and/or monoclonal antibodies (mAbs) (tixagevimab/cilgavimab or sotrovimab). The main outcome was a complete virological response (negative SARS-CoV-2 RT-PCR on nasopharyngeal swabs) at the end of treatment. Fifteen patients were included as follows: eleven (11/15; 73%) with hematological disease and four (4/15; 27%) with recently diagnosed HIV/AIDS infection. Six patients (6/15; 40%) received a single antiviral course, four patients (4/15; 27%) received an antiviral and mAbs sequentially, and two patients (13%) received three lines of treatment (a sequence of three antivirals or two antivirals and mAbs). A combination of two antivirals or one antiviral plus mAbs was administered in three cases (3/15, 20%). One patient died while still positive for SARS-CoV-2, while fourteen (14/15; 93%) tested negative within 16 days after the end of treatment. The median time to negativization since the last treatment was 2.5 days. Both sequential and combination regimens used in this study demonstrated high efficacy and safety in the high-risk group of immunosuppressed patients.

Background and Objectives: Stenotrophomonas maltophilia is a ubiquitous, aerobic, Gram-negative bacillus causing increasing concern in patients affected by haematological malignancies. Materials and Methods: We report a case series from two centres in Northern Italy to describe the characteristics, outcome and microbiological response of S. maltophilia infections in patients with haematological malignancies and/or allogenic hematopoietic stem cell transplantation (aHSCT). Results: Ten patients were included. The median age was 67 years, and seven patients (70%) were males. The median Charlson Comorbidity Index was 6 (IQR: 4–8). The most frequent haematological comorbidities were acute myeloid leukaemia (AML; n = 3; 30%) and non-Hodgkin’s lymphoma (n = 3; 30%). Three (30%) patients underwent aHSCT before infection, all for AML. All the patients had undergone a recent antibiotics course and had an indwelling central venous catheter before infection. The main clinical presentations were nosocomial pneumonia, with (2; 20%) or without (4; 40%) secondary bloodstream infection and CRBSI (3; 30%). Four patients were treated with cefiderocol in monotherapy or combinations therapy with cotrimoxazole. The rest of the patients were treated with cotrimoxazole or levofloxacin in monotherapy. Conclusions: Despite a high rate of clinical improvement (90%) after starting antimicrobial therapy, we faced high 30-day mortality (30%) and in-hospital mortality (50%) rates in a highly comorbid population.

Background: Cefiderocol is a novel parenteral siderophore cephalosporin, demonstrating enhanced activity against multidrug-resistant (MDR) Gram-negative bacteria and difficult-to-treat Acinetobacter baumannii (DTR-AB). Plasma-free trough concentration (fC_trough) over the minimum inhibitory concentration (MIC) was reported as the best pharmacokinetic parameter to describe the microbiological efficacy of cefiderocol. Materials and methods: We retrospectively described the pharmacokinetic and pharmacodynamic profile of three critically ill patients admitted to the intensive care unit, receiving cefiderocol under compassionate use to treat severe DTR-AB infections while undergoing continuous venovenous haemofiltration. Cefiderocol was administrated at a dosage of 2 g every 8 h infused over 3 h. Therapeutic drug monitoring (TDM) was assessed at the steady state. Cthrough was evaluated by assuming a plasma protein binding of 58.0%. The fCmin/MIC was calculated assuming a cefiderocol MIC equal to the PK-PD breakpoint of susceptibility ≤ 2. The association between the PK/PD parameters and microbiological outcome was assessed. Results: fC_trough/MIC were >12 in 2 patients and 2.9 in the 1 who rapidly recovered from renal failure. Microbiological cure occurred in 3/3 of patients. None of the 3 patients died within 30 days. Conclusions: A cefiderocol dosage of 2 g q8 h in critically ill patients with AKI undergoing CVVH may bring about a very high plasma concentration, corresponding to essentially 100% free time over the MIC for DTR-AB.

Nocardiosis is an uncommon Gram-positive bacterial infection caused by aerobic actinomycetes in the genus Nocardia, usually occurring in individuals with a weakened immune system (diabetes, malignancies, HIV/AIDS, transplantation, immunosuppressive drugs), but immunocompetent hosts are also widely involved.¹ Nocardiosis has a wide range of clinical manifestations, with pulmonary nocardiosis being the most frequent. Due to the lack of prospective controlled trials, graded recommendations for the treatment of nocardiosis have not yet been proposed.² In fact, trimethoprim/sulfamethoxazole is mainly regarded as a first-line therapy, and combination regimens are required in severe infections.³ Alternative agents to trimethoprim/sulfamethoxazole are essential in allergic patients or those developing adverse effects or when isolates are resistant to trimethoprim/sulfamethoxazole. Given that clinical isolates of Nocardia spp. are often resistant to multiple antimicrobial agents and treatment duration is usually longer than 6 months, the therapeutic management of this infection remains challenging. In spite of the broad use of trimethoprim/sulfamethoxazole, different regimens have been used with antimicrobial drugs active against Gram-positive bacteria.⁴ Among these approaches, one possible antimicrobial class of choice are the oxazolidinones. Nocardia spp. is almost always susceptible to linezolid, whose use in long-term treatment is limited by the risk of drug-related toxicities. Tedizolid, an oxazolidinone-class antibiotic approved only for the treatment of acute bacterial skin and skin structure infections, has been increasingly used in recent years as off-label indication for infection requiring prolonged treatment. Safety profile, pharmacokinetic (PK) properties and high tissue penetration make it a potential alternative to linezolid in pulmonary infections.⁵ There are few data on the role of tedizolid in nocardiosis and, to the best of our knowledge, no data are available so far about the use of therapeutic drug monitoring (TDM) or pharmacogenomics.^6,7