Inclusion Criteria: 

• Subjects scheduled to elective and/or urgent median sternotomy for cardiac surgery, who are preoperative hemodynamically stable. 
• Males and females. 
• Subjects of age 18 years and older. 
• Subjects with both Diabetes Mellitus AND BMI ≥ 30 OR Diabetes Mellitus/BMI ≥ 30 AND at least one of the following: 
  • Current/Previous smoking history ≥ 30 pack year;
  • Chronic Obstructive Pulmonary Disease (COPD).
• Female of childbearing potential should have a negative serum pregnancy test prior to index procedure.
  • Note: All female of childbearing potential must agree to use a highly effective method of contraception (such as double barrier, oral or parenteral hormonal, intrauterine device and spermicide) consistently and correctly for the duration of the study. 
• Subject is willing and able to provide a signed Informed Consent Form and is willing and able to comply with study's procedures including follow-up visits.

Exclusion Criteria:

• Subjects undergoing partial sternotomy. 
• Subjects with any preoperative active significant infection. 
• Subjects that received oral or IV doxycycline during the last 4 weeks prior to screening. 
• Subjects with sensitivity to doxycycline and/or to tetracycline family of drugs and/or other study drug ingredients. 
• Subjects with known allergies to more than 3 substances (an allergy questionnaire will be filled during the screening process). 
• Subjects with history of allergic/hypersensitivity reaction to any substance having required hospitalization and/or treatment with intra-venous steroids/epinephrine or in the opinion of the investigator the patient is at high risk of developing severe allergic/hypersensitivity reactions. 
• Subjects with uncontrolled Asthma (GINA III-IV). 
• Subjects with chronic urticaria. 
• Immunocompromised subjects from any reason, at screening. 
• Subjects with renal failure requiring dialysis. 
• Subjects scheduled to major organ transplantation and/or to other significant concomitant surgical procedure. 
• Subjects scheduled for mechanical assist device. 
• Subjects scheduled to be treated with preventive negative pressure devices.
• Subjects undergone Cerebro-Vascular Accident (CVA)/Transient Ischemic Attack (TIA) within the past 3 months prior to randomization. 
• Subjects that have undergone previously, any cardiac surgery through sternotomy. 
• Subjects with active or previous malignancy in the chest area. 
• Any subject with active malignancy or with malignancy that has not been in complete remission for at least 5 years. Subjects who have had carcinoma in situ of the cervix, squamous cell carcinoma of the skin and basal cell carcinoma of the skin, are eligible. 
• Pregnant or breast-feeding women or women of childbearing age not protected by an effective contraceptive method of birth control (such as double barrier, oral or parenteral hormonal, intrauterine device and spermicide). 
• Subjects enrolled in any intervention study with an investigational medicinal product and/or received any investigational medicinal product within 30 days or 5½ half-lives of the product prior to enrollment (whichever is longer). 
• In the opinion of investigator, subject is not eligible to participate in the study and/or to comply with protocol requirements (e.g., due to a cognitive, medical condition or residency distanced from site that may jeopardize Follow-Up visits attendance etc.).