Comparative antianaerobic activities of the ketolides HMR 3647 (RU 66647) and HMR 3004 (RU 64004).

1997 ◽  
Vol 41 (9) ◽  
pp. 2019-2022 ◽  
Author(s):  
L M Ednie ◽  
M R Jacobs ◽  
P C Appelbaum

HMR 3647 (RU 66647) and HMR 3004 (RU 64004), two ketolides, had MICs at which 50% of the strains are inhibited (MIC50s) of 0.06 to 0.125 microg/ml and MIC90s of 16.0 microg/ml against 352 anaerobes. MIC50s and MIC90s of erythromycin, azithromycin, clarithromycin, and roxithromycin were 0.5 to 2.0 microg/ml and 32.0 to >64.0 microg/ml, respectively. HMR 3647 and HMR 3004 were more active against non-Bacteroides fragilis-group anaerobes (other than Fusobacterium mortiferum, Fusobacterium varium, and Clostridium difficile).

1997 ◽  
Vol 41 (5) ◽  
pp. 1037-1041 ◽  
Author(s):  
L M Ednie ◽  
S K Spangler ◽  
M R Jacobs ◽  
P C Appelbaum

Agar dilution methodology (with added Oxyrase in the case of the macrolide group to allow incubation without added CO2) was used to compare the activity of RU 64004, a new ketolide, with the activities of erythromycin, azithromycin, clarithromycin, roxithromycin, clindamycin, amoxicillin with and without clavulanate, piperacillin with and without tazobactam, metronidazole, and imipenem against 379 anaerobes. Overall, RU 64004 yielded an MIC at which 50% of the isolates are inhibited (MIC50) of 1.0 microg/ml and an MIC90 of 16.0 microg/ml. In comparison, MIC50s and MIC90s of erythromycin, azithromycin, clarithromycin, and roxithromycin were 2.0 to 8.0 and >64.0 microg/ml, respectively. MICs of macrolides, including RU 64004, were higher for Bacteroides ovatus, Fusobacterium varium, Fusobacterium mortiferum, and Clostridium difficile than for the other species. RU 64004 was more active against gram-positive rods and cocci, Prevotella and Porphyromonas spp., and fusobacteria other than F. mortiferum and F. varium than against the Bacteroides fragilis group. Overall MIC50s and MIC90s (in micrograms per milliliter), respectively, of other compounds were as follows: clindamycin, 1.0 and 16.0; amoxicillin, 4.0 and 64.0; amoxicillin-clavulanate, 0.5 and 4.0; piperacillin, 8.0 and >64.0; piperacillin-tazobactam, 1.0 and 16.0; metronidazole, 1.0 and 4.0; and imipenem, 0.25 and 1.0.


Anaerobe ◽  
1995 ◽  
Vol 1 (5) ◽  
pp. 269-274 ◽  
Author(s):  
Elisabeth Nagy ◽  
Ildikó Szőke ◽  
Mria Gacs ◽  
Károly Csiszár

2011 ◽  
Vol 56 (3) ◽  
pp. 1247-1252 ◽  
Author(s):  
James A. Karlowsky ◽  
Andrew J. Walkty ◽  
Heather J. Adam ◽  
Melanie R. Baxter ◽  
Daryl J. Hoban ◽  
...  

ABSTRACTClinical isolates of theBacteroides fragilisgroup (n= 387) were collected from patients attending nine Canadian hospitals in 2010-2011 and tested for susceptibility to 10 antimicrobial agents using the Clinical and Laboratory Standards Institute (CLSI) broth microdilution method.B. fragilis(59.9%),Bacteroides ovatus(16.3%), andBacteroides thetaiotaomicron(12.7%) accounted for ∼90% of isolates collected. Overall rates of percent susceptibility were as follows: 99.7%, metronidazole; 99.5%, piperacillin-tazobactam; 99.2%, imipenem; 97.7%, ertapenem; 92.0%, doripenem; 87.3%, amoxicillin-clavulanate; 80.9%, tigecycline; 65.9%, cefoxitin; 55.6%, moxifloxacin; and 52.2%, clindamycin. Percent susceptibility to cefoxitin, clindamycin, and moxifloxacin was lowest forB. thetaiotaomicron(n= 49, 24.5%),Parabacteroides distasonis/P. merdae(n= 11, 9.1%), andB. ovatus(n= 63, 31.8%), respectively. One isolate (B. thetaiotaomicron) was resistant to metronidazole, and two isolates (bothB. fragilis) were resistant to both piperacillin-tazobactam and imipenem. Since the last published surveillance study describing Canadian isolates ofB. fragilisgroup almost 20 years ago (A.-M. Bourgault et al., Antimicrob. Agents Chemother. 36:343–347, 1992), rates of resistance have increased for amoxicillin-clavulanate, from 0.8% (1992) to 6.2% (2010-2011), and for clindamycin, from 9% (1992) to 34.1% (2010-2011).


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