Clinical manifestations and prognostic factors of Morganella morganii bacteremia

Although Morganella morganii causes a variety of clinical infections, there are limited studies on M. morganii bacteremia after the year 2000. A total of 109 patients with M. morganii bacteremia at a medical center in Taiwan from 2003 to 2012 were studied. Among them, 30.3 % had polymicrobial bacteremia and 75.2 % had community-acquired infection. The most common underlying diseases were hypertension (62.4 %) and diabetes mellitus (38.5 %). The urinary tract (41.3 %) was the major portal of entry, followed by the hepatobiliary tract (27.5 %), skin and soft tissue (21.1 %), and primary bacteremia (10.1 %). Susceptibility testing of M. morganii isolates showed ubiquitous resistance to first-generation cephalosporins and ampicillin-clavulanate; resistance rates to gentamicin, piperacillin-tazobactam, and ciprofloxacin were 30.3 %, 1.8 %, and 10.1 %, respectively. Overall, the 14-day mortality was 14.7 %. Univariate analysis revealed that elevated blood urea nitrogen (BUN) values [p = 0.0137, odds ratio (OR) 5.26], intensive care unit (ICU) admission (p = 0.011, OR 4.4), and higher Acute Physiology and Chronic Health Evaluation II (APACHE II) scores (p < 0.001, OR 1.62) were significantly associated with mortality. The APACHE II score remained the only significant risk factor for mortality in multivariate analysis (p = 0.0012, OR 1.55). In conclusion, M. morganii bacteremia patients were mostly elderly, with one or more comorbidities. Most of the patients had community-acquired infection via the urinary and hepatobiliary tracts. Furthermore, prognosis can be predicted according to disease severity measured by the APACHE II score.