Antimicrobial susceptibility of flavobacteria as determined by agar dilution and disk diffusion methods

Abstract

A total of 106 clinical isolates of flavobacteria, including 41 isolates of Flavobacterium meningosepticum, 59 of Flavobacterium indologenes, and 6 of Flavobacterium odoratum were collected from January 1992 to December 1995 from patients in Taiwan. The in vitro activities of antimicrobial agents were determined concomitantly by the standard agar dilution and disk diffusion methods. More than 90% of the flavobacterial isolates were resistant to cephalothin, cefotaxime, ceftriaxone, moxalactam, aztreonam, imipenem, aminoglycosides, erythromycin, and glycopeptides. The majority of F. meningosepticum isolates were susceptible to piperacillin and to minocycline but resistant to ceftazidime, with MICs at which 90% of the isolates are inhibited being 8, 4, and > 128 microg/ml, respectively. Approximately half of the F. indologenes isolates were susceptible to piperacillin, cefoperazone, ceftazidime, and minocycline, with MICs at which 50% of the isolates are inhibited being 4, 16, 8, and 4 microg/ml, respectively. The majority of F. odoratum isolates were resistant to all the antimicrobial agents tested except minocycline, to which five of six isolates were susceptible. With least-squares regression analysis and error rate-bounded analysis methods, the following resistant and susceptible zone diameter breakpoints were established: < or = 12 and > or = 17 mm, respectively, for piperacillin against F. meningosepticum and F. indologenes; < or = 13 and > or = 18 mm, respectively, for ceftazidime against F. meningosepticum and F. indologenes, < or = 17 and > or = 21 mm, respectively, for ofloxacin against F. indologenes; < or = 16 and > or = 20 mm, respectively, for ciprofloxacin against F. meningosepticum. Valid breakpoints for the disk diffusion method could not be established for cefoperazone and ofloxacin against F. meningosepticum and for minocycline against F. meningosepticum and F. indologenes due to a poor correlation coefficient for the regression line or for cefoperazone and ciprofloxacin against F. indologenes due to the presence of remarkable error rates.

Pyonephrosis due to Chryseobacterium gleum: A first case report

“…Both, C. meningosepticum, and C. indologenes, are resistant to most antimicrobial agents used to treat Gram-negative bacteria but are susceptible to agents used to treat Gram-positive bacterial infections like vancomycin, erythromycin and clindamycin. [7] However, the present strain of C. gleum, was resistant to vancomycin, erythromycin and clindamycin which is consistent with an earlier study, [8] emphasising the need for speciation and antimicrobial susceptibility for these group of NFGNBs. Though ciprofloxacin and newer fluoroquinolones (garenoxacin, gatifloxacin and levofloxacin) have been cited as the most appropriate antimicrobial agents to treat Chryseobacterium spp.…”

Septic shock, pneumonia, and soft tissue infection due to Myroides odoratimimus: report of a case and review of Myroides infections

“…Based on the results of sensitivity testing studies published to date in the literature, the susceptibility of M. odoratimimus to various classes of antibiotics appears to mirror that of M. odoratus, but at a lower level [24][25][26][27]. Actually, the strain isolated from our patient retained susceptibility only to carbapenems and antipseudomonal penicillins, and was resistant to all other b-lactams tested (including aztreonam), as well as to aminoglycosides, quinolones, and trimethoprim/sulfamethoxazole.…”

“…The treatment of Myroides infection is often difficult, since most strains are resistant to the b-lactams, including aztreonam and carbapenems, and exhibit variable susceptibility to aminoglycosides, quinolones, and sulfamethoxazole [24][25][26]. Based on the results of sensitivity testing studies published to date in the literature, the susceptibility of M. odoratimimus to various classes of antibiotics appears to mirror that of M. odoratus, but at a lower level [24][25][26][27].…”

Myroides Infection in a Baboon After Prolonged Pig Kidney Graft Survival

“…is characterized by resistance to a wide range of antimicrobial agents that have satisfactory activity against other Gram-negative bacteria. Most strains are resistant to the β-lactams, including aztreonam and carbapenems, and exhibit variable susceptibility to aminoglycosides, quinolones, and sulfamethoxazole (39, 40). Resistance to β-lactams is due to the production of chromosome-encoded metallo-β-lactamases, both in M. odoratum (TUS-1) and M. odoratimimus (MUS) (41).…”