title: Clinical characteristics of the patients with bacteremia due to Moraxella catarrhalis in children: a case-control study.
abstract: BACKGROUND
  Invasive diseases due to Moraxella catarrhalis are rare in children, even in immunocompromised hosts. Therefore, data regarding clinical characteristics and risk factors of such patients are limited. The aim of this study is to compare the clinical characteristics of patients with bacteremia due to Moraxella catarrhalis against those with bacteremia due to Streptococcus pneumoniae and Haemophilus influenzae.
  
  
  METHODS
  We performed a retrospective case-control study to compare patients younger than 18 years of age with positive blood cultures for the three pathogens between June 2008 and May 2014 at our institution. Data regarding patients' demographics and clinical course were collected from their medical records. Three group comparisons, with M. catarrhalis as reference, were made by the Fisher's exact test and Wilcoxon rank sum test for discrete and continuous variables, respectively.
  
  
  RESULTS
  There were eight cases of M. catarrhalis, 110 cases of S. pneumoniae (105 patients) and 22 cases of H. influenzae. The M. catarrhalis group consisted of six females (75 %) with a mean age of 16 months. The majority of patients (7/8, 88 %) had underlying diseases; however, only one was immunocompromised. Characteristically, six patients (75 %) had medical devices including trans-nasal devices (5/8, 63 %). Univariate analysis revealed that underlying conditions (P = 0.005), trans-nasal devices (P < 0.001), and lower body weight (P = 0.016) and low white blood cell count (P = 0.011) at the onset of illness were associated with the M. catarrhalis group compared to the S. pneumoniae group. Meanwhile, the higher rates of the patients with underlying conditions and trans-nasal devices were associated with the M. catarrhalis group compared to the H. influenzae group (P = 0.039, P < 0.001, respectively).
  
  
  CONCLUSIONS
  The presence of underlying conditions, particularly in those with trans-nasal devices, were characteristic features of patients with bacteremia due to M. catarrhalis.
authors: Division of Infectious Diseases, Department of Medical Subspecialties, National Center for Child Health and Development, 2-10-1 Okura, Setagayaku, Tokyo, 1578535, Japan. funaki-t@ncchd.go.jp.
authors: Takanori
authors: T
authors: Funaki
authors: Center for Clinical Research and Development, National Center for Child Health and Development, 2-10-1 okura, Setagayaku, Tokyo, 1578535, Japan. inoue-ei@ncchd.go.jp.
authors: Eisuke
authors: E
authors: Inoue
authors: Division of Infectious Diseases, Department of Medical Subspecialties, National Center for Child Health and Development, 2-10-1 Okura, Setagayaku, Tokyo, 1578535, Japan. miyairi-i@ncchd.go.jp.
authors: Isao
authors: I
authors: Miyairi
mesh_terms: D016470:Bacteremia / Q000382:microbiology* / Q000503:physiopathology*; D016022:Case-Control Studies; D005260:Female; D006192:Haemophilus Infections / Q000150:complications; D006193:Haemophilus influenzae; D006801:Humans; D007223:Infant; D008297:Male; D001936:Moraxella catarrhalis; D045828:Moraxellaceae Infections / Q000150:complications / Q000503:physiopathology*; D011008:Pneumococcal Infections / Q000150:complications; D012189:Retrospective Studies; D013296:Streptococcus pneumoniae