The pilot study "ARIIBO" was conducted to analyze changes in immune parameters reported in obese subjects, which had never been the subject of a global study outside of an infectious context, and studied in period septic only sporadically. This study was intended to contribute to a better understanding of the probably adverse impact of obesity on the immune response to bacterial infections, and to describe a specific immunological profile of an infectious excess risk in obese subjects.

In terms of infection, obesity is a risk factor due to "mechanical" and pharmacodynamic variations, but also to the immune system. One of the best studied immunological parameters in obese patients, leptin resistance, is associated with a decrease in innate and adaptive immunity through a modification of the lymphocyte and cytokine profile.

It is important to compare the data collected in obese patients infected (first study called "ARIIBO"), with those of non-obese subjects presenting the same type of infection, which will be included in the study "ARIIBACT"

Inclusion Criteria:

• age between 18 and 80 years
• BMI 18 to 25
• presence of a bacterial infection
• pneumopathy (documented or probable)
• acute pyelonephritis / prostatitis
• skin and soft tissue infection (erysipelas, fasciitis, excluding pressure ulcers)
• cholecystitis / cholangitis,
• surgical site infection
• signed informed consent

Exclusion Criteria:

• patients with documented viral, parasitic or mycotic infections
• patients with bacterial infection> 4 weeks (eg endocarditis, osteoarticular infections)
• patients followed in intensive unit care
• patients with progressive cancerous pathology or malignant hemopathy diagnosed in the previous five years
• patients with systemic diseases (connective tissue diseases, vasculitis)
• known immunodepression syndrome (CVID, HIV ...)
• immunosuppressive therapy in progress until less than one month before inclusion (corticosteroids, DMARDs, biotherapies, hydroxychloroquine)