Flavobacterium meningosepticum bacteremia: an analysis of 16 cases.

BACKGROUND: Flavobacterium meningosepticum is an uncommon pathogen causing nosocomial pneumonia and meningitis in newborns. It is usually resistant to antimicrobial agents used to treat gram-negative bacilli. While the pathogen often results in high mortality and serious sequelae in newborns, it is also found to cause to disease in adults. Therefore, it is necessary to know the full spectrum of the infection in adults and to identify effective antimicrobial agents.

METHOD: Microbiology logbooks were reviewed for F meningosepticum isolated from January, 1992, to March, 1996. The medical records of these patients were reviewed. Special attention was paid to clinical manifestations, underlying diseases, risk factors, treatments, and prognosis. Twenty-four antimicrobial agents were tested using antimicrobial susceptibility tests.

RESULTS: Eighteen isolates of F meningosepticum were identified from 16 patients. There were 10 men and six women, with a mean age of 63.7 years. The clinical features of infection included fever (> or = 38 degrees C) in 13 patients, chills in seven, shortness of breath in four, rales or rhonchi in four, shock in three and flank pain in two. All except one patient survived without sequelae. Fifteen patients contracted F meningosepticum from nosocomial sources. Of them, seven were suspected to have acquired the pathogen from diagnostic or therapeutic procedures. Bacteremia occurred in these patients within a mean period of 2.2 days. The other eight patients suffered nosocomial bacteremia within a mean period of 33.4 days after admission. The suspected infection route was not identified in only one patient. The organism was resistant to penicillins, cephalosporins, aztreonam, imipenem, aminoglycosides and macrolides. Testing with lomefloxacin, ciprofloxacin and ofloxacin yielded 72.2%, 83.3% and 94.4% susceptibility rates, respectively. Rifampin (61.1%) and trimethoprim-sulfamethoxazole (TMP-SMX) (88.9%) were effective. Vancomycin and minocycline were 100% effective.

CONCLUSIONS: F meningosepticum is an opportunistic pathogen of low virulence and rarely causes serious infections in adults. Reducing the use of unnecessary residual devices and invasive procedures may help reduce the incidence of infection. Therapeutic options include vancomycin, TMP-SMX, minocycline, rifampin or fluoroquinolones.