PneumoniaPneumonia, BacterialPneumonia, ViralPneumonia, PneumococcalCryptogenic Organizing PneumoniaPneumonia, PneumocystisPneumonia, StaphylococcalPneumonia, Ventilator-AssociatedPneumonia, AspirationCommunity-Acquired InfectionsPneumonia, MycoplasmaPneumonia, LipidLung Diseases, InterstitialLungAnti-Bacterial AgentsIdiopathic Interstitial PneumoniasStreptococcus pneumoniaeMycoplasma pneumoniaeMurine pneumonia virusPneumocystis jiroveciiPneumocystisBronchoalveolar Lavage FluidRadiography, ThoracicRetrospective StudiesProspective StudiesLegionnaires' DiseaseCross InfectionRisk FactorsHospitalizationTreatment OutcomePulmonary EosinophiliaTrimethoprim-Sulfamethoxazole CombinationBronchopneumoniaRespiration, ArtificialIncidencePneumonia, Progressive Interstitial, of SheepIntensive Care UnitsInfant, NewbornFatal OutcomeVentilators, MechanicalBronchoalveolar LavageSeverity of Illness IndexAcute DiseaseRespiratory Tract InfectionsAnti-Infective AgentsPneumonia of Swine, MycoplasmalBronchoscopyPseudomonas InfectionsPneumococcal VaccinesPneumocystis cariniiEmpyemaTime FactorsTomography, X-Ray ComputedImmunocompromised HostCase-Control StudiesPulmonary FibrosisInfluenza, HumanSputumLegionella pneumophilaAIDS-Related Opportunistic InfectionsCohort StudiesBacteremiaPleural EffusionLegionellaPneumococcal InfectionsChild, HospitalizedPentamidineChlamydial PneumoniaLung DiseasesPasteurellosis, PneumonicAge FactorsSyndromePrognosisKlebsiella InfectionsConfusionSepsisDisease Models, AnimalIdiopathic Pulmonary FibrosisKlebsiella pneumoniaeLength of StayPseudomonas aeruginosaHaemophilus InfectionsOpportunistic InfectionsRespiratory InsufficiencySensitivity and SpecificityBiopsyChlamydophila pneumoniaeNasopharynxFollow-Up StudiesPneumovirus InfectionsPneumocystis InfectionsPrevalenceLung AbscessVirus DiseasesPasteurella InfectionsAdrenal Cortex HormonesSeasonsComorbidityCalcitoninGram-Negative Bacterial Infections