Ventilator Associated pneumonia (VAP) is associated with longer ICU length of stay, prolonged mechanical ventilation, and increased use of antimicrobials, health-care cost and mortality . Acute respiratory infections (ARIs) comprise a large and heterogeneous group of infections, including bacterial infections, viral infections, and infections of other etiologies. Early initiation of adequate antibiotic therapy is the cornerstone in the treatment. However, overuse of antibiotics and prolonged duration of antibiotic therapy in patients with bacterial ARIs in the hospital and intensive care setting is associated with increased resistance for common bacteria, high costs, and adverse drug reactions.

Inclusion Criteria:

• 18 years old or greater
• Ventilator associated pneumonia (VAP) with positive sputum culture.

Exclusion Criteria:

• pregnancy,
• use of immunosuppressive agents except for steroids,
• neutropenia (white blood cell count ≤1000/mL)
• patients whose primary diagnosis was community acquired pneumonia and other source of infection.

patients having ventilator associated pneumonia (VAP) with positive sputum culture. VAP was considered if the onset occurred following intubation of the trachea for 48 h and the infection was absent before starting mechanical ventilation . Diagnosis of pneumonia was based on radiographic finding of pulmonary infiltrate; findings should be new and progressive and at least should satisfy two clinical criteria of the following: body temperature >38°C or <35.5°C; leukocyte count > 12,000 cells/mm3 or <4000 cells/mm3; and clinical evidence of pneumonia, such as purulent secretions and a decrease in oxygenation.

Diagnosis of VAP was confirmed microbiologically by positive bronchial secretion cultures