Rapid microbiological reports to clinicians are related to improved clinical outcomes. We conducted a 3-year quasi-experimental design, specifically a pretest¿posttest single group design in a university medical center, to evaluate the clinical impact of rapid microbiological identification information using MALDI-TOF MS on optimizing antibiotic prescription. A total of 363 consecutive hospitalized patients with bacterial infections were evaluated comparing a historical control group (CG) (n = 183), in which the microbiological information (bacterial identification and antibiotic susceptibility) was reported jointly to the clinician between 18:00 h and 22:00 h of the same day and a prospective intervention group (IG) (n = 180); the bacterial identification information was informed to the clinician as soon as it was available between 12:00 h and 14:00 h and the antibiotic susceptibility between 18:00 h and 22:00 h). We observed, in favor of IG, a statistically significant decrease in the information time (11.44 h CG vs. 4.48 h IG (p < 0.01)) from the detection of bacterial growth in the culture medium to the communication of identification. Consequently, the therapeutic optimization was improved by introducing new antibiotics in the 10¿24 h time window (p = 0.05) and conversion to oral route (p = 0.01). Additionally, we observed a non-statistically significant decrease in inpatient mortality (global, p = 0.15; infection-related, p = 0.21) without impact on hospital length of stay. In conclusion, the rapid communication of microbiological identification to clinicians reduced reporting time and was associated with early optimization of antibiotic prescribing without worsening clinical outcomes.

IntroductionSuspected infectious diseases located in difficult-to-access sites can be challenging due to the need for invasive procedures to isolate the etiological agent. Positron emission tomography (PET) is a non-invasive imaging technology that can help locate the infection site. The most widely used radiotracer for PET imaging (2-deoxy-2[F-18] fluoro-D-glucose: [F-18]FDG) shows uptake in both infected and sterile inflammation. Therefore, there is a need to develop new radiotracers able to specifically detect microorganisms. MethodsWe tested two specific radiotracers: 2-deoxy-2-[F-18]-fluoro-D-sorbitol ([F-18]FDS) and 2-[F-18]F-rho-aminobenzoic acid ([F-18]FPABA), and also developed a simplified alternative of the latter for automated synthesis. Clinical and reference isolates of bacterial and yeast species (19 different strains in all) were tested in vitro and in an experimental mouse model of myositis infection. Results and discussionNon-lactose fermenters (Pseudomonas aeruginosa and Stenotrophomonas maltophilia) were unable to take up [F-18]FDG in vitro. [F-18]FDS PET was able to visualize Enterobacterales myositis infection (i.e., Escherichia coli) and to differentiate between yeasts with differential assimilation of sorbitol (i.e., Candida albicans vs. Candida glabrata). All bacteria and yeasts tested were detected in vitro by [F-18]FPABA. Furthermore, [F-18]FPABA was able to distinguish between inflammation and infection in the myositis mouse model (E. coli and Staphylococcus aureus) and could be used as a probe for a wide variety of bacterial and fungal species.

Background: The main objective was to evaluate the efficacy of intranasal photodynamic therapy (PDT) in SARS-CoV-2 mildly symptomatic carriers on decreasing the infectivity period. SARS-CoV-2-specific immune-stimulating effects and safety were also analysed. Methods: We performed a randomized, placebo-controlled, clinical trial in a tertiary hospital (NCT05184205). Patients with a positive SARS-CoV-2 PCR in the last 48 hours were recruited and aleatorily assigned to PDT or placebo. Patients with pneumonia were excluded. Participants and investigators were masked to group assignment. The primary outcome was the reduction in in vitro infectivity of nasopharyngeal samples at days 3 and 7. Additional outcomes included safety assessment and quantification of humoral and T-cell immune-responses. Findings: Patients were recruited between December 2021 and February 2022. Most were previously healthy adults vaccinated against COVID-19 and most carried Omicron variant. 38 patients were assigned to placebo and 37 to PDT. Intranasal PDT reduced infectivity at day 3 post-treatment when compared to placebo with a ß-coefficient of -812.2 (CI95%= -478660 ¿ -1.3, p<0.05) infectivity arbitrary units. The probability of becoming PCR negative (ct>34) at day 7 was higher on the PDT-group, with an OR of 0.15 (CI95%=0.04-0.58). There was a decay in anti-Spike titre and specific SARS-CoV-2 T cell immunity in the placebo group 10 and 20 weeks after infection, but not in the PDT-group. No serious adverse events were reported. Interpretation: Intranasal-PDT is safe in pauci-symptomatic COVID-19 patients, it reduces SARS-CoV-2 infectivity and decelerates the decline SARS-CoV-2 specific immune-responses.

Pseudomonas aeruginosa is a pathogen that has a high propensity to develop antibiotic resistance, and the emergence of multidrug-resistant strains is a major concern for global health. The mortality rate associated with infections caused by this microorganism is significant, especially those caused by multidrug-resistant strains. The antibiotics used to treat these infections include quinolones, aminoglycosides, colistin, and beta-lactams. However, novel combinations of beta-lactams-beta-lactamase inhibitors and cefiderocol offer advantages over other members of their family due to their better activity against certain resistance mechanisms. Selecting the appropriate empiric antibiotic treatment requires consideration of the patient's clinical entity, comorbidities, and risk factors for multidrug-resistant pathogen infections, and local epidemiological data. Optimizing antibiotic pharmacokinetics, controlling the source of infection, and appropriate collection of samples are crucial for successful treatment. In the future, the development of alternative treatments and strategies, such as antimicrobial peptides, new antibiotics, phage therapy, vaccines, and colonization control, holds great promise for the management of P. aeruginosa infections.

In the last few years there has been an increase of implantable cardiac electronic device and vascular graft related infections. This is due in part to a higher complexity of some of these procedures and an increase in patient's comorbidities. Despite wide diagnosis methods availability, early stage diagnosis usually constitutes a challenge as often patients only denote insidious symptoms. In most confirmed cases, removal of the infected device is required to resolve the infection. This is mostly explainable because of bacterial ability to grow as biofilms on biomaterial surfaces, conferring them antimicrobial resistance. If removal is not possible, chronic suppressive antimicrobial therapy could be an option.

Infections caused by Staphylococcus aureus have had classically an important impact in morbidity and mortality in the nosocomial and community scene. The description of methicillin resistance among nosocomial isolates of S. aureus and his widespread diffusion has become methicillin-resistant S. aureus (MRSA) in one of the most common causes of bacterial nosocomial infections. In the last years MRSA strains have also emergence in the community. This together with a progressive increase in resistance to antibiotics used classically has become vancomycin in the treatment of choice in most cases according to clinical guidelines. As a result, a progressive rise in the minimum inhibitory concentration (MIC) to vancomycin has been reported. In this context strains with intermediate susceptibility to vancomycin (MIC 8-4 mg/L) and heteroresistance have been noted. These strains are associated with a higher risk of treatment failure when using vancomycin. Among isolates of S. aureus susceptible to vancomycin there has been described stains with elevated MICs (¿1.5 mg/L). It is controversial if the presence of these strains has an impact on clinical outcome if treatment with vancomycin or ß-lactams is prescribed. The development of new antibiotics with activity against MRSA and exploring synergies offer a promising alternative to treatment with vancomycin.