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Hybrid immunity, resulting from a combination of SARS-CoV-2 infection and vaccination, offers robust protection against COVID-19 in the general population. However, its impact on immunocompromised patients remains unexplored. We investigated the effect of hybrid immunity against the Omicron variant in a population of kidney transplant recipients receiving the fourth dose mRNA monovalent vaccination. By extracting data from the clinical records and performing individual interviews, participants were categorized into the hybrid cohort (previously infected and vaccinated individuals) and the vaccine cohort (vaccinated-only individuals). The study comprised 1114 participants, 442 in the hybrid and 672 in the vaccine cohorts. From April 2022 to August 2023, 286 infections, 38 hospitalizations and 9 deaths were reported. The cumulative incidence of infection was 12.1% (95% confidence interval [CI], 9.03-16.03) for the hybrid cohort and 36.54% (95% CI, 32.81-40.54) for the vaccine cohort after 300 days of follow-up. Hybrid immunity was associated to a 72% lower risk of infection (adjusted hazard ratio, 0.28; 95% CI, 0.21-0.38) and a 96% lower risk of hospitalization (adjusted hazard ratio, 0.04; 95% CI, 0.01-0.32). No deaths occurred in the hybrid cohort. Hybrid immunity was associated with a lower incidence of SARS-CoV-2 infection and severe COVID-19, underscoring its importance for risk stratification in this vulnerable patient population., Competing Interests: Declaration of competing interest The authors of this manuscript have conflicts of interest to disclose as described by the American Journal of Transplantation. J.M. Cruzado is the Associate Editor of the American Journal of Transplantation. Other authors of this manuscript have no conflicts of interest to disclose as described by the American Journal of Transplantation., (Copyright © 2024 American Society of Transplantation & American Society of Transplant Surgeons. Published by Elsevier Inc. All rights reserved.)

Objectives: The usefulness of routine microbiological testing for rationalising antibiotic use in hospitalised patients with community-acquired pneumonia (CAP) continues to be a subject of debate. We aim to determine the effect of positive microbiological testing on antimicrobial de-escalation and clinical outcomes in CAP., Methods: A retrospective analysis of a prospectively collected cohort of non-immunosuppressed adults hospitalised with CAP was performed. The primary study outcome was antimicrobial de-escalation. Secondary outcomes included 30-day case-fatality rate, adverse events, and CAP recurrence. Adjustment for confounders was performed by inverse probability weighting propensity score, logistic regression, and cause-specific Cox model., Results: Of 3677 patients with CAP, 1924 (52.3%) had any positive microbiological test. Antimicrobial de-escalation was performed in 648/1924 (33.7%) of patients with positive microbiological testing and in 179/1753 (10.2%) of those with non-positive results. When propensity score was entered into the multivariate analysis, positive microbiological testing (adjusted OR (AOR)], 2.59; 1.96-3.41) and clinical stability at day 3 (AOR 1.87; 1.45-2.10) were two of the main factors independently associated with antimicrobial de-escalation. After applying an adjusted cause-specific Cox model, antimicrobial de-escalation was not associated with a higher 30-day case-fatality rate (adjusted hazard ratio (AHR), 0.44 (95% CI, 0.14-1.43)), higher frequency of adverse events (AHR, 0.77 (95% CI, 0.53-1.12)), or CAP recurrence (AHR, 0.65 (95% CI, 0.35-1.14))., Discussion: Antimicrobial de-escalation was more often performed in hospitalised patients with CAP who had positive microbiological tests than in those with non-positive results, and it did not adversely affect relevant clinical outcomes., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Long-term adaptive immune memory has been reported among immunocompetent individuals up to eight months following SARS-CoV-2 infection. However, limited data is available in convalescent patients with a solid organ transplant. To investigate this, we performed a thorough evaluation of adaptive immune memory at different compartments (serological, memory B cells and cytokine [IFN-γ, IL-2, IFN-γ/IL12 and IL-21] producing T cells) specific to SARS-CoV-2 by ELISA and FluoroSpot-based assays in 102 convalescent patients (53 with a solid organ transplants (38 kidney, 5 liver, 5 lung and 5 heart transplant) and 49 immunocompetent controls) with different clinical COVID-19 severity (severe, mild and asymptomatic) beyond six months after infection. While similar detectable memory responses at different immune compartments were detected between those with a solid organ transplant and immunocompetent individuals, these responses were predominantly driven by distinct COVID-19 clinical severities (97.6%, 80.5% and 42.1%, all significantly different, were seropositive; 84% vs 75% vs 35.7%, all significantly different, showed IgG-producing memory B cells and 82.5%, 86.9% and 31.6%, displayed IFN-γ producing T cells; in severe, mild and asymptomatic convalescent patients, respectively). Notably, patients with a solid organ transplant with longer time after transplantation did more likely show detectable long-lasting immune memory, regardless of COVID-19 severity. Thus, our study shows that patients with a solid organ transplant are capable of maintaining long-lasting peripheral immune memory after COVID-19 infection; mainly determined by the degree of infection severity., (Copyright © 2022 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

The protective capacity and duration of humoral immunity after SARS-CoV-2 infection are not yet understood in solid organ transplant recipients. A prospective multicenter study was performed to evaluate the persistence of anti-nucleocapsid IgG antibodies in liver transplant recipients 6 months after coronavirus disease 2019 (COVID-19) resolution. A total of 71 liver transplant recipients were matched with 71 immunocompetent controls by a propensity score including variables with a well-known prognostic impact in COVID-19. Paired case-control serological data were also available in 62 liver transplant patients and 62 controls at month 3 after COVID-19. Liver transplant recipients showed a lower incidence of anti-nucleocapsid IgG antibodies at 3 months (77.4% vs. 100%, p < .001) and at 6 months (63.4% vs. 90.1%, p < .001). Lower levels of antibodies were also observed in liver transplant patients at 3 (p = .001) and 6 months (p < .001) after COVID-19. In transplant patients, female gender (OR = 13.49, 95% CI: 2.17-83.8), a longer interval since transplantation (OR = 1.19, 95% CI: 1.03-1.36), and therapy with renin-angiotensin-aldosterone system inhibitors (OR = 7.11, 95% CI: 1.47-34.50) were independently associated with persistence of antibodies beyond 6 months after COVID-19. Therefore, as compared with immunocompetent patients, liver transplant recipients show a lower prevalence of anti-SARS-CoV-2 antibodies and more pronounced antibody levels decline., (© 2021 The American Society of Transplantation and the American Society of Transplant Surgeons.)

Objectives: To determine the prevalence of smoking and alcohol abuse among patients with invasive pneumococcal disease (IPD) in order to promote prevention strategies., Methods: We prospectively studied all culture-proven IPD cases in patients aged ≥ 18 years during the period 1997-2011. The habits of smoking and alcohol abuse were evaluated. Pneumococcal serotyping was performed., Results: There were 1378 IPD cases, with a mean age of 61 ± 17 years; 65% were males. Compared to the general population aged 18-64 years, patients with IPD of the same age group were more often current smokers (57% vs. 35%, p < 0.001) and alcohol abusers (21% vs. 6%, p < 0.001). Among patients with IPD, young adults (aged 18-49 vs. 50-64 vs. ≥ 65 years) were more commonly current smokers (71% vs. 40% vs.14%, p < 0.001) and alcohol abusers (23% vs. 18% vs. 6%, p < 0.001). Males were more frequently smokers and alcohol abusers than females. Smokers and alcohol abusers more often had underlying diseases such as HIV infection and chronic liver disease. Pneumonia was more common in smokers and peritonitis in alcohol abusers. Alcohol abuse conferred higher mortality. Certain pneumococcal serotypes, such as serotypes 1, 8, and 23F, more frequently caused IPD in smokers, and serotypes 4, 11A, and 19F in alcohol abusers., Conclusions: Smoking and alcohol abuse are the most preventable risk factors for IPD. Implementing smoking and alcohol abuse cessation programs and a pneumococcal vaccination schedule are essential to diminish the burden of pneumonia and other pneumococcal infections., (Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Between 1996 and 2002, 103 hospitalised patients yielding one or more clinical isolates of extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-EC) were identified. A significant increase was observed in the incidence of ESBL-EC colonisation or infection during the study period (1.65 episodes/100 000 patient-days in 1996 to 12.6 episodes/100 000 patient-days in 2002; p 0.01). Infection developed in 70 (68%) patients (75 episodes), with surgical site (44%) and urinary tract (17%) infections being the most frequent. Pulsed-field gel electrophoresis showed extensive clonal diversity among the isolates. A case-control study and multivariate analysis identified female gender (OR 2.1; p 0.01), use of a nasogastric tube (OR 3.5; p 0.001) and previous antibiotic therapy (OR 3.9; p < 0.001) as independent variables associated with acquisition of ESBL-EC. The study demonstrated a progressive increase in the number of ESBL-EC isolates in a non-epidemic setting. Most cases of ESBL-EC colonisation or infection occurred in hospitalised patients exposed to invasive procedures and antibiotic pressure.