title: A cohort study of bacteremic pneumonia: The importance of antibiotic resistance and appropriate initial therapy?
abstract: Bacteremic pneumonia is usually associated with greater mortality. However, risk factors associated with hospital mortality in bacteremic pneumonia are inadequately described.The study was a retrospective cohort study, conducted in Barnes-Jewish Hospital (2008-2015). For purposes of this investigation, antibiotic susceptibility was determined according to ceftriaxone susceptibility, as ceftriaxone represents the antimicrobial agent most frequently recommended for hospitalized patients with community-acquired pneumonia as opposed to nosocomial pneumonia. Two multivariable analyses were planned: the first model included resistance to ceftriaxone as a variable, whereas the second model included the various antibiotic-resistant species (methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, and Enterobacteriaceae).In all, 1031 consecutive patients with bacteremic pneumonia (mortality 37.1%) were included. The most common pathogens associated with infection were S aureus (34.1%; methicillin resistance 54.0%), Enterobacteriaceae (28.0%), P aeruginosa (10.6%), anaerobic bacteria (7.3%), and Streptococcus pneumoniae (5.6%). Compared with ceftriaxone-susceptible pathogens (46.8%), ceftriaxone-resistant pathogens (53.2%) were significantly more likely to receive inappropriate initial antibiotic treatment (IIAT) (27.9% vs 7.1%; P < 0.001) and to die during hospitalization (41.5% vs 32.0%; P = 0.001). The first logistic regression analysis identified IIAT with the greatest odds ratio (OR) for mortality (OR 2.2, 95% confidence interval [CI] 1.5-3.2, P < 0.001). Other independent predictors of mortality included age, mechanical ventilation, immune suppression, prior hospitalization, prior antibiotic administration, septic shock, comorbid conditions, and severity of illness. In the second multivariable analysis that included the antibiotic-resistant species, IIAT was still associated with excess mortality, and P aeruginosa infection was identified as an independent predictor of mortality (OR 1.6, 95% CI 1.1-2.2, P = 0.047), whereas infection with ceftriaxone-resistant Enterobacteriaceae (OR 0.6, 95% CI 0.4-1.0, P = 0.050) was associated with lower mortality.More than one-third of our patients hospitalized with bacteremic pneumonia died. IIAT was identified as the most important risk factor for hospital mortality and the only risk factor amenable to potential intervention. Specific antibiotic-resistant pathogen species were also associated with mortality.
authors: Division of Pulmonary, Critical Care, and Sleep Medicine Division of Infectious Diseases, University of New Mexico School of Medicine, Albuquerque, NM Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine St. Louis College of Pharmacy, St. Louis, MO.
authors: Cristina Vazquez
authors: CV
authors: Guillamet
authors: Rodrigo
authors: R
authors: Vazquez
authors: Jonas
authors: J
authors: Noe
authors: Scott T
authors: ST
authors: Micek
authors: Marin H
authors: MH
authors: Kollef
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D016470:Bacteremia / Q000188:drug therapy* / Q000382:microbiology* / Q000401:mortality; D002443:Ceftriaxone / Q000627:therapeutic use; D024881:Drug Resistance, Bacterial; D004755:Enterobacteriaceae / Q000187:drug effects; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects; D008875:Middle Aged; D018410:Pneumonia, Bacterial / Q000188:drug therapy* / Q000382:microbiology* / Q000401:mortality; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D012189:Retrospective Studies
chemical_list: D000900:Anti-Bacterial Agents; D002443:Ceftriaxone