title: Impact of bacterial coinfection on clinical outcomes in pneumococcal pneumonia.
abstract: The aim of this study was to investigate the influence of bacterial coinfection on patients with pneumococcal pneumonia. We retrospectively analyzed the incidence, clinical features, microbial distributions, and outcomes of patients with bacterial coinfection in a cohort of 433 hospitalized patients with pneumococcal pneumonia. Eighty-five patients (19.6 %) were diagnosed with bacterial coinfection; the most frequent pathogens were Haemophilus influenzae (25 patients, 33.3 %), methicillin-susceptible Staphylococcus aureus (MSSA) (15 patients, 20.0 %), and Moraxella catarrhalis (13 patients, 17.3 %). The CURB-65 score and pneumonia severity index (PSI) were significantly higher in patients with bacterial coinfection (both P < 0.001). In addition, the proportion of patients with bacterial coinfection who met the Infectious Disease Society of America (IDSA)/American Thoracic Society (ATS) severe pneumonia criteria was significantly higher (P < 0.001). Multivariate logistic regression analysis identified three risk factors for bacterial coinfection in patients with pneumococcal pneumonia: alcoholism (odds ratio [OR], 5.12; 95 % confidence interval (95 % CI), 1.60-16.4; P = 0.006), hospitalization for 2 days or more within 90 days preceding admission (OR, 2.02; 95 % CI, 1.03-3.98; P = 0.041), and residence in a nursing home or extended care facility (OR, 3.22; 95 % CI, 1.48-6.97; P = 0.003). Multivariate analysis for 30-day mortality showed that bacterial coinfection was a significant adverse prognostic factor (OR, 2.50; 95 % CI, 1.13-5.53; P = 0.023), independent of IDSA/ATS severe pneumonia, PSI, or healthcare-associated pneumonia. In conclusion, bacterial coinfection may have an adverse impact on severity and outcomes of pneumococcal pneumonia.
authors.affiliation: Department of Respiratory Medicine, Kurashiki Central Hospital, 1-1-1 Miwa, Kurashiki, Okayama, 710-0052, Japan, skumagai1212@gmail.com.
authors.forename: S
authors.initials: S
authors.lastname: Kumagai
authors.forename: T
authors.initials: T
authors.lastname: Ishida
authors.forename: H
authors.initials: H
authors.lastname: Tachibana
authors.forename: Y
authors.initials: Y
authors.lastname: Ito
authors.forename: A
authors.initials: A
authors.lastname: Ito
authors.forename: T
authors.initials: T
authors.lastname: Hashimoto
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D060085:Coinfection / Q000188:drug therapy / Q000401:mortality*; D017714:Community-Acquired Infections / Q000382:microbiology; D003428:Cross Infection / Q000382:microbiology; D005260:Female; D006192:Haemophilus Infections / Q000150:complications / Q000188:drug therapy / Q000453:epidemiology*; D006193:Haemophilus influenzae / Q000187:drug effects; D006801:Humans; D008297:Male; D001936:Moraxella catarrhalis / Q000187:drug effects; D045828:Moraxellaceae Infections / Q000150:complications / Q000188:drug therapy / Q000453:epidemiology*; D011018:Pneumonia, Pneumococcal / Q000150:complications / Q000188:drug therapy / Q000453:epidemiology*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013203:Staphylococcal Infections / Q000150:complications / Q000188:drug therapy / Q000453:epidemiology*; D013211:Staphylococcus aureus / Q000187:drug effects; D013296:Streptococcus pneumoniae / Q000187:drug effects; D016896:Treatment Outcome