CTTI Risk Factors for HABP/VABP Study

Inclusion Criteria (Adult arm =\> 18 years old): * Admission to participating ICU * Hospitalized for \>48 hours or admitted \<7 days after discharge from an inpatient acute or chronic care facility High-Risk Inclusion (Adult arm =\> 18 years old): Treated with one or more of the following respiratory modalities for at least 12 hours, either currently or within the prior 7 days: * Invasive mechanical ventilation * Noninvasive ventilation (BiPAP or CPAP for any indication other than obstructive sleep apnea) * High-flow, supplemental oxygen therapy via nasal cannula. Only include systems that using an air/oxygen blender capable of delivering a precise FiO2 level, not just a flow in LPM. * High flow supplemental oxygen therapy delivering at least 50% FiO2 via aerosol facemask or tracheostomy collar (mask). Only include systems using an air/oxygen blender capable of delivering a precise FiO2 level, not just a flow in LPM. * Supplemental oxygen therapy delivered via either partial or non-rebreather face mask Other-ICU Inclusion(Adult arm =\> 18 years old): All patients who meet ICU and time-frame eligibility criteria, but do not fulfill high-risk criteria, and are receiving an antibiotic for treatment of LRTI or undifferentiated sepsis. Exclusion Criteria(Adult arm =\> 18 years old): * Age \<18 years old * Pregnancy (current) or breastfeeding * Lung cancer or another malignancy metastatic to the lungs (currently receiving treatment) * Patient previously enrolled and treated for suspected HABP or VABP (More than CRF Part 1 was previously completed) * Patient is on comfort measures (e.g. would not receive antibiotics) Inclusion Criteria (Pediatric Arm: \< 18 years old) * \< 18 years old * Admission to participating ICU or intermediate care unit * Hospitalized for \>48 hours or admitted \<7 days after discharge from an inpatient acute or chronic care facility Note: Children and infants with pulmonary and cardiac anomalies are eligible to participate. High-Risk Inclusion (Pediatric Arm: \< 18 years old) Subjects ≥120 days old and \<18 years old: Currently treated with one or more of the following respiratory modalities for at least 24 hours: * Invasive mechanical ventilation via endotracheal intubation * New initiation of mechanical ventilation, BiPAP or CPAP via tracheostomy * Noninvasive ventilation (BiPAP or CPAP for any indication other than obstructive sleep apnea) * High-flow, supplemental oxygen therapy delivering at least 1.5LMP with 100% FiO2 via nasal cannula when delivered using an air/oxygen blender capable of delivering a precise FiO2 level, not just a flow in LPM * High flow supplemental oxygen therapy delivering at least 50% FiO2 via aerosol facemask or tracheostomy collar (mask) when delivered using an air/oxygen blender capable of delivering a precise FiO2 level, not just a flow in LPM * Supplemental oxygen therapy delivered via either partial or non-rebreather face mask Subjects \<120 days old: Currently treated with mechanical ventilation via endotracheal intubation for at least 5 days Standard-Risk Inclusion (Pediatric Arm: \< 18 years old) All patients who meet pediatric eligibility criteria, but do not fulfill high-risk criteria, and are receiving an antibiotic for treatment of LRTI or undifferentiated sepsis. Exclusion Criteria (Pediatric Arm: \< 18 years old) * Known pregnancy (current) or breastfeeding * Lung cancer or another malignancy metastatic to the lungs (currently receiving treatment) * Patient previously enrolled and treated for suspected HABP or VABP (More than Pediatric CRF Part 1 was previously completed) * Patient is on comfort measures (e.g. would not receive antibiotics)