Omicron Breakthrough Infection After Heterologous Prime-Boost Vaccination Induces a Vigorous Antibody Response.

Infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant is usually asymptomatic or mild and appears to be poorly immunogenic at least in unvaccinated individuals. Here, we found that health care workers vaccinated with 2 doses of Sputnik V and a booster dose of ChAdOx1 mount a vigorous neutralizing-antibody response after Omicron breakthrough infection.

Evaluation of endotoxin release and cytokine production induced by antibiotics in patients with Gram-negative nosocomial pneumonia.

OBJECTIVE: To determine the plasma concentrations of lipopolysaccharide, tumor necrosis factor-alpha, interleukin-1 beta, and interleukin-6 in a homogeneous group of septic patients and to evaluate the effect of antibiotic treatment, imipenem or ceftazidime, on the release of lipopolysaccharide and cytokines. DESIGN: Prospective, randomized study. SETTING: Sixteen-bed multidisciplinary intensive care unit. PATIENTS: Twenty-four septic patients with documented Gram-negative nosocomial pneumonia. Controls were 20 patients admitted without sepsis and 20 healthy volunteers. INTERVENTIONS: Septic patients were randomized between imipenem and ceftazidime. Blood samples were collected before (0 hrs) and after (4 and 12 hrs) antibiotic treatment. Concentrations of lipopolysaccharide were measured by using the limulus assay, and cytokine concentrations were measured by enzyme-linked immunosorbent assay. Statistical analyses were performed by Kruskal-Wallis test, Mann-Whitney U test, and Student's t-test. MEASUREMENTS AND MAIN RESULTS: The mean age was 48.5 +/- 19.5. The mean Acute Physiology and Chronic Health Evaluation II score was 18.4 +/- 4.5. Overall mortality rate was 45.4%. All septic patients showed significant higher concentrations of lipopolysaccharide (p <.001), tumor necrosis factor-alpha (p <.04), and interleukin-6 (p <.001) than the controls, but interleukin-1 beta was never detected. We did not find statistically significant changes in lipopolysaccharide or cytokine plasma concentrations over time within any of the two arms of the study (ceftazidime vs. imipenem). There were no statistically significant differences in lipopolysaccharide and interleukin-6 plasma concentrations between the two antibiotic treatments. Although tumor necrosis factor-alpha plasma concentrations were significantly higher in the group treated with ceftazidime compared with the group treated with imipenem at the baseline and 4 hrs later, these differences were not statistically significant after 12 hrs of initiation of both treatments. CONCLUSIONS: Patients with Gram-negative nosocomial pneumonia have high plasma concentrations of lipopolysaccharide, interleukin-6, and tumor necrosis factor-alpha, but the antibiotic therapy evaluated did not significantly modify these concentrations.

Fracaso del tratamiento con penicilina en un caso de meningitis por Neisseria meningiditis / Failure of treatment with penicillin in a case of meningitis by Neisseria meningitidis

Neisseria meningitidis fue considerada hasta 1985 como uniformemente sensible a penicilina (Concentración inhibitoria mínima, C.I,M., ó 0,06 mg/L), y la mortalidad relacionada con meningitis meningocóccica ha sido baja. En los últimos años se han aislado cepas moderadamente sensibles a penicilina (C.I.M.:0,12-1 mg/L) en España, Inglaterra, Sudáfrica, Estado Unidos y Argentina. Se presenta el caso de un joven de 16 años de edad que se interna con diagnóstico de meningitis meningocóccica, obteniéndose líquido cefalorraquídeo con cultivo positivo para Neisseria meningitidis grupo C. Se inicia tratamiento con penicilina G (300.ooo UI/Kg). A los tres días de tratamiento se efectúa una nueva punción lumbar, obtiéndose desarrollo de N. meningitidis grupo C. La C.I.M. demonstró que el germen era moderadamente sensible a penicilina, probablemente debido a modificaciones en las proteínas ligadoras de penicilina. Se cambia el esquema antibiótico a ceftriaxona (50 mg/Kg). El paciente fue dado de alta, sin secuelas neurológicas, después de 14 días de tratamiento endovenoso. Este caso ilustra de qué manera, pequeños cambios en la sensibilidad de N. meningitideis pueden ser clínicamente significativos