Factors increasing the need for hospitalization include:

Age greater than 65
Underlying chronic illnesses
Respiratory rate greater than 30 per minute
Systolic blood pressure less than 90 mmHg
Heart rate greater than 125 per minute
Temperature below 35 or over 40 °C
Confusion
Evidence of infection outside the lungLaboratory results indicating hospitalization include:

Arterial oxygen tension less than 60 mm Hg
Carbon dioxide over 50 mmHg or pH under 7.35 while breathing room air
Hematocrit under 30 percent
Creatinine over 1.2 mg/dl or blood urea nitrogen over 20 mg/dl
White-blood-cell count under 4 × 10^9/L or over 30 × 10^9/L
Neutrophil count under 1 x 10^9/LX-ray findings indicating hospitalization include:

Involvement of more than one lobe of the lung
Presence of a cavity
Pleural effusion

Prognosis
The CAP outpatient mortality rate is less than one percent, with fever typically responding within the first two days of therapy, and other symptoms abating in the first week. However, X-rays may remain abnormal for at least a month. Hospitalized patients have an average mortality rate of 12 percent, with the rate rising to 40 percent for patients with bloodstream infections or those who require intensive care. Factors increasing mortality are identical to those indicating hospitalization. When CAP does not respond to treatment, this may indicate a previously unknown health problem, a treatment complication, inappropriate antibiotics for the causative organism, a previously unsuspected microorganism (such as tuberculosis) or a condition mimicking CAP (such as granuloma with polyangiitis). Additional tests include X-ray computed tomography, bronchoscopy or lung biopsy. Epidemiology
CAP is common worldwide, and is a major cause of death in all age groups.
The fear was that contact lens wearers who used their solution were at higher risk of acanthamoebic keratitis than contact lens wearers who used other solutions. The manufacturer recalled the product after the Centers for Disease Control in the United States found that 21 people had possibly received an Acanthamoeba infection after using Complete Moisture Plus in the month prior to diagnosis. As a bacterial reservoir
Several species of bacteria that can cause human disease are also able to infect and replicate within Acanthamoeba species. These include Legionella pneumophila, Pseudomonas aeruginosa, and some strains of Escherichia coli and Staphylococcus aureus. For some of these bacteria, replication inside Acanthamoeba has been associated with enhanced growth in macrophages, and increased resistance to some antibiotics. Furthermore, due to the high prevalence of Acanthamoeba in the environment, these amoebae have been proposed to serve as an environmental reservoir for some human pathogens. Ecology
A. castellanii can be found at high densities in various soil ecosystems. It preys on bacteria, but also fungi and other protozoa. This species is able to lyse bacteria and produce a wide range of enzymes, such as cellulases or chitinases, and probably contributes to the breakdown of organic matter in soil, contributing to the microbial loop.