Hospital-acquired pneumonia (HAP) is defined as an infection of the pulmonary parenchyma that develops in patients admitted to hospital for more than 48 hours and that was not incubating at the time of admission. It represents one of the most common and serious nosocomial infections, associated with significant morbidity, prolonged hospitalisation, and increased mortality in critically ill patients.

The aetiology of HAP is primarily driven by micro-aspiration of bacteria colonising the oropharynx and upper gastrointestinal tract. Pathogen distribution is shaped by the duration of hospitalisation, prior antibiotic exposure, local epidemiology, and patient characteristics. Multidrug-resistant (MDR) organisms are particularly prevalent in patients with prolonged inpatient stay and intensive care unit (ICU) admission, as critically ill patients become rapidly colonised with nosocomial pathogens.

Ventilator-associated pneumonia (VAP), a subgroup of nosocomial pneumonia, occurs in patients requiring tracheal intubation and mechanical ventilation for at least 48 hours. A clinically important and increasingly recognised entity is ventilated HAP (v-HAP), defined as HAP that subsequently requires tracheal intubation and mechanical ventilation. Emerging evidence indicates that v-HAP carries the highest mortality among nosocomial pneumonia subtypes in ICU patients - exceeding VAP - while non-ventilated ICU-acquired HAP carries the lowest mortality.

All subjects will be subjected to Complete history taking including demographic characteristics, diagnosis on admission to hospital, previous antibiotic treatment in the last 90 days, antibiotics upon which HAP developed, antibiotics described for HAP treatment, hospital stay before diagnosis of hospital-acquired pneumonia and before ICU admission, steroid use, inhalation antibiotic use, length of ICU stay, length of hospital stay, chronic underlying diseases,and APACHE II score. Vital signs, complete lab investigation sputum and blood cultures, Imaging, and arterial blood gases will be collected as soon as HAP diagnosis is settled and the following indices will be recorded

1. CURB-65 and CRB-65 scores: The score is an acronym for each of the risk factors measured. Each risk factor scores one point, for a maximum score of 5: Confusion of new onset, Urea > 7 mmol/l (Blood Urea Nitrogen >19), Respiratory rate of 30 breaths per minute or greater, Blood pressure less than 90 mmHg systolic or diastolic blood pressure 60 mmHg or less and Age 65 or older [4].
2. SMART-COP and SMRT-CO: The score is also an acronym for each of the risk factors measured; Systolic blood pressure (<90 mmHg, 2 points); Multilobar chest radiography involvement (1 point); low Albumin level (<3.5 g/dl, 1 point); high respiratory Rate (≤50 years: ≥25 br/min,>50 years: ≥30 br/min; 1 point); Tachycardia (≥125 bpm; 1 point); Confusion (new onset; 1 point); poor Oxygenation (≤50 years: PaO2 < 70 mmHg or O2 saturation ≤ 93%,>50 years: PaO2 <60 mmHg or O2 saturation <90%; 2 points); and low arterial PH (<7.35; 2 points)[5].

Inclusion Criteria:

All patients diagnosed with HAP in the chest department, Assiut University

Exclusion Criteria:

1. Post operative patients
2. Tracheostomized patients
3. Comatosed patient since admission
4. Suspected aspiration

• Adult patients (age ≥18 years) admitted to the Chest Department or Respiratory ICU, Assiut University Hospitals
• Diagnosis of HAP confirmed according to standard clinical, radiological, and microbiological criteria
• Hospital admission for more than 48 hours prior to pneumonia onset
• Ability to provide informed consent