In vitro activity of grepafloxacin (OPC-17116) against anaerobic bacteria

DIAGN MICROBIOLINFECT DIS 1994;19:129-133

129

NOTE

In vitro Activity of Grepafloxacin (OPC-17116) Against Anaerobic Bacteria Hannah M. Wexler, Eric Molitoris, and Sydney M. Finegold

In vitro activity of the quinolone grepafloxacin (0PC-17116) was compared with that of ciprofloxacin, fleroxacin, clindamycin, imipenem, and metronidazole by using the NCCLS-approved Brucella-base-laked blood agar dilution method and breakpoints, when available. Clindamycin, metronidazole, and imipenem inhibited ~98% of Bacteroides fragilis at the breakpoint; grepafloxacin, ciprofloxacin, and fleroxacin inhibited 83%, 6%, and O, respectively, at 2 ~g/ml. Grepafloxacin

inhibited 39% of other B. fragilis group species isolates (80) at breakpoint (<-2 p,g/ml) compared with 100% for metronidazole and imipenem, 83% for clindamycin, 6% for ciprofloxacin, and 1% for fleroxacin. Grepafloxacin demonstrated substantially better activity against B. fragilis than did ciprofloxacin or fleroxacin; overall activity against anaerobes was marginally better than that of ciprofloxacin or fleroxacin.

Most of the quinolone agents introduced over the past several years, including ciprofloxacin, lomefloxacin, norfloxacin, pefloxacin, enoxacin, cinoxacin, and ofloxacin, have had only limited activity against anaerobes. Activity against the Bacteroides fragilis group organisms has been poor, in general. Variable activity against Prevotella species, such as the P. melaninogenica and P. oralis group, and against B. ureolyticus has been reported. The newer fluoroquinolones (for example, sparfloxacin, WIN 57273, Bay Y 3118, clinafloxacin and CI-990, and DU-6859a) have increased activity against B. fragilis (Goldstein

and Citron, 1992; Venezia et al., 1990; Wexler et al., 1992; Marshall and Jones, 1993; Sato et al., 1992). Studies in our laboratory yielded percent susceptible to these agents of 78%, 100%, 100%, 100%, 94%, and 100%, respectively. This study evaluated the in vitro activity of a new fluoroquinolone, grepafloxacin (formerly OPC-17116), against a wide variety of clinical anaerobic isolates. Antimicrobial agents were obtained as powders as indicated: grepafloxacin (Otsuka America Pharmaceutical, Rockville, MD, USA); fleroxacin (Hoffmann La Roche, Nutley, NJ, USA); clindamycin (Upjohn, Kalamazoo, MI, USA); imipenem (Merck, Sharp and Dohme, Rahway, NJ, USA); and ciprofloxacin, chloramphenicol, and m e t r o n i d a z o l e (Sigma, St. Louis, MO, USA). All bacteria were randomly selected recent clinical isolates from the Veterans Administration Wadsworth Medical Center (Los Angeles, CA, USA). Bacteria were identified according to established procedures (Holdeman et al., 1977; Summanen et al., 1993). Minimum inhibitory concentrations (MICs) were determined by an agar dilution technique described previously using an inoculum of 10s colony-forming units per spot as specified by the National Committee for Clinical Laboratory Standards (NCCLS, 1993), and Brucella-

From the Medical (S.M.F.) and Research (H.M.W.) Services, Veterans Administration Medical Center, West Los Angeles, Wadsworth Division; and the Departments of Medicine (H.M.W., E.M., S.M.F.) and Microbiologyand Immunology (S.M.F.), UCLA School of Medicine, Los Angeles, California, USA. Address reprint requests to Dr. H.M. Wexler, Microbial Diseases Research Laboratory, Building 304, Room E3-224, VAMC West Los Angeles 691/151J, Los Angeles, CA 90073, USA. Received 8 February 1994; revised and accepted 24 February 1994. This work was presented at the 33rd Interscience Conference for Antimicrobial Agents and Chemotherapy, New Orleans, Louisiana, 1993. © 1994 Elsevier Science Inc., 655 Avenue of the Americas, New York, NY 10010 0732-8893/94/$7.00

H.M. Wexler et al.

130

TABLE 1

Activity of Antimicrobial A g e n t s Against Anaerobes

Antimicrobial Agent

Bacteroides fragilis

Range

MICso

MICgo

% Susceptible ~

(53 strains)

Grepafloxacin Ciprofloxacin Fleroxacin Clindamycin Imipenem Metronidazole

1-16 2->32 4->32 0.062->32 0.062-1 0.125-2

Other B. fragilis group species Grepafloxacin Ciprofloxacin Fleroxacln Clindamycin Imipenem Metronidazole

2 4 8 0.5 0.125 0.5

8 16 16 1 0.25 1

11, 0, 0, 94, 100, 100,

83, 6, 0, 98, 100, 100,

89 77 30 98 100 100

8 32 32 8 0.5 1

6, 5, 0, 61, 100, 100,

39, 6, 1, 83, 100, 100,

83 20 18 93 100 100

(80)b 0.5-32 0.5->32 2->32 0.062->32 0.062-1 0.062-2

4 16 16 2 0.25 0.5

Bacteroides gracilis (10) Grepafloxacin Ciprofloxacin Fleroxacin Clindamycin Imipenem Metronidazole Other Bacteroides species Grepafloxacin Ciprofloxacin Fleroxacm Clindamycin Imipenem Metronidazole

Porphyromonas species

0.062 0.062 0.125 0.125 0.5 0.25

100, 100, 100, 100, 100, 100,

100, 100, 100, 100, 100, 100,

100 100 100 100 100 100

0.125-8 0.062-8 0.25-8 0.062-0.5 0.062-0.5 0.1254

4

2 4 0.062 0.125 0.125

4 4 8 0.25 0.125 1

45, 45, 36, 100, 100, 100,

45, 55, 36, 100, 100, 100,

91 91 55 100 100 100

0.125-2 0.5-4 0.25-8 0.062->32 0. 062-0.125 0. 062-0.125

0.5 1 2 0.062 0.125 0.125

2 2 8 0.062 0.125 0.125

58, 67, 42, 92, 100, 100,

100, 100 92, 100 58, 83 92, 92 100, 100 100, 100

1-32 1->32 2-32 0.062-0.062 0. 062-0.125 0.062-8

4 2 4 0.062 0.125 0.5

16 16 16 0.062 0.125 2

23, 19, 0, 100, 100, 100,

29, 65 65, 74 26, 58 100, 100 100, 100 100, 100

1-4 2-4 0.25-32 0.062-0.125 0.062-2 0.062-0.125

2 2 8 0.062 0.062 0.125

4 4 32 0.125 2 0.125

33, 0, 20, 100, 100, 100,

60, 100 80, 100 20, 47 100, 100 100, 100 100, 100

(11)a

(31)e

Grepafloxacin Ciprofloxacin Fleroxacin Clindamycin Imipenem Metronidazole

Fusobacterium nucleatum

(14)

Grepafloxacin Ciprofloxacin Fleroxacin Clindamycin Imipenem Metronidazole

Fusobacterium mortiferum/F, varium group Grepafloxacin Ciprofloxacin Fleroxacin Clindamycin

0.062 0.062 0.125 0.062 0.25 0.125

(11)c

Grepafloxacin Ciprofloxacin Fleroxacin Clindamycin Imipenem Metronidazole

PrevoteUa species

0.062-0.5 0.062-0.062 0.125-0.5 0. 062-0.125 0.25-0.5 0.125-0.5

(13) 4-32 2-32 4->32 0.062-8

32 8 32 0.5

32 16 32 4

0, 0, 15 0, 31, 38 0, 0, 8 62, 92, 100

(Continued)

Note

TABLE I

131

(Continued)

Antimicrobial Agent

Range

Imipenem Metronidazole Other Fusobacterium species Grepafloxacin Ciprofloxacin Fleroxacin Clindamycin Imipenem Metronidazole

MICso

0.25-2 0.125-0.5

1 0.25

1-32 0.25-4 2-32 0.062-1 0.062-0.5 0.125-0.5

4 2 4 0.062 0.125 0.125

0.062-1 0.062-0.25 0.125-1 0.062-0.5 0.125-0.25 0.125-0.25

0.5 0.062 0.5 0.25 0.125 0.125

MICgo 1 0.5

% Susceptible a 100, 100, 100 100, 100, 100

(8)f

h

q

33, 44, 0, 100, 100, 100,

33, 89, 11, 100, 100, 100,

56 100 67 100 100 100

100, 100, 100, 100, 100, 100,

100, 100, 100, 100, 100, 100,

100 100 100 100 100 100

Bilophila wadsworthia (22) Grepafloxacin Ciprofloxacin Fleroxacin Clindamycin Imipenem Metronidazole

1 0.25 1 0.5 0.125 0.125

Clostridium difficile (9)g Grepafloxacin Fleroxacin Ciprofloxacin Clindamycin Imipenem Metronidazole

Clostridium perfringens

8-32 16-32 8-16 1->32 4-8 0.25-1

m

m

m

0, 0, 0 0, 0, 0 0, 0, 0 22, 44, 56 33, 100, 100 100, 100, 100

(11)

Grepafloxacin Ciprofloxacin Fleroxacin Clindamycin Imipenem Metronidazote

Clostridium ramosum

16 16 8 8 8 0.25

0.125-2 0.25-2 0.5-8 0.062-4 0.062-0.5 0.5-2

1

0.5 2 0.25 0.125 1

2 1 2 4 0.25 2

73, 91, 45, 82, 100, 100,

100, 100, 91, 100, 100, 100,

100 100 91 100 100 100

9~ 45, 0, 9, 0, 0, 9, 64, 100, 100, 100, 100,

100 55 0 73 100 100

80, 40, 20, 100, 100, 100,

80, 60, 20, 100, 100, 100,

100 100 60 100 100 100

68 40, 8, 96, 100, 100,

80, 64, 40, 96, 100, 100,

92 80 48 96 100 100

(11)

Grepafloxacin Ciprofloxacin Fleroxacin Clindamycin Imipenem Metronidazole

1-4 2-16 16-32 2->32 0.125-1 0.5-2

Other Clostridium species Grepafloxacin Ciprofloxacin Fleroxacin Clindamycin Imipenem Metronidazole

(5)h

Peptostreptococcus species

(23)i

Grepafloxacin Ciprofloxacin Fleroxacin Clindamycin Imipenem Metronidazole Gram-positive rods (non-spore-forming) Grepafloxacin

4 4 16 4 0.5 0.5

0.5-4 1-4 1-32 0.062-2 0.125-2 0.125--0.5

2 4 0.5 0.5 0.25

0.125-8 0.25-32 0.062->32 0.062->32 0.062-0.125 0.125-2

1 2 8 0.125 0.125 0.5

1

4 8 32 >32 1 2 m

m

m

h

4 16 >32 2 0.125 2

(24y 0.25-16

16

38, 63, 71

(Continued)

H.M. Wexler et al.

132

TABLE 1

(Continued)

Range

MICso

MIC9o

Ciprofloxacin Fleroxacin Clindamycin Imipenem Metronidazole

0.125-16 0.5->32 0.062-2 0.062-0.5 0.125->128

2 4 0.125 0.125 4

16 >32 1 0.25 >128

Total (336) Grepafloxacin Ciprofloxacin Fleroxacin Clindamycin Imipenem Metronidazole

0.062-32 0.062->32 0.062->32 0.062->32 0.062-8 0.062->128

2 4 8 0.25 0.125 0.5

Antimicrobial Agent

8 16 32 4 0.5 1

% Susceptible a 42, 4, 100, 100, 54,

71, 75 21, 50 100, 100 100, 100 54, 58

32, 27, 16, 82, 98, 97,

59, 81 44, 65 24, 43 92, 95 100, 100 97, 97

aPercent susceptible is reported at one dilution below the breakpoint, at the breakpoint, and at one dilution above the breakpoint. Breakpoints used to determine the percent susceptible were 2 ~g/ml for grepafloxacin, ciprofloxacin, and fleroxacin; 4 ~g/ml for clindamycin; 8 ~g/ml for imipenem; and 16 ~g/ml for metronidazole. The breakpoints for the quinolone agents are not approved by the National Committee for Clinical Laboratory Standards for anaerobes and are used for comparison purposes only; the breakpoint for ciprofloxacin is one dilution greater than that used for aerobic bacteria (1 ~g/ml). bIncludes B. caccae (3), B. distasonis (9), B. ovatus (9), B. stercoris (6), B. thetaiotaomicron (30), B. uniformis (9), and B. vulgatus (14). qncludes B. capillosus (2), B. splanchnicus (5), B. ureolyticus (2), and other Bacteroides species (2). dIncludes P. asaccharolytica (4), P. endodontalis (2), P. gingivalis (4), and other Porphyromonas species (1). qncludes P. bivia (4), P. buccae(1), P. corporis (2), P. denticola (1), P. disiens (1), P. intermedia (8), P. loescheii (5), P. melaninogenica (5), P. oralis (1), P. oris (1), P. zoogleoformans (1), and other Prevotella species (1). tlncludes F. gonidiaformans (1), F. necrogenes (1), F. necrophorum (3), and other Fusobacterium species (3). ~Breakpoint is used only as a reference point. Clostridium difficile is primarily of interest in relation to antimicrobial-induced pseudomembranous colitis. These data must be interpreted in the context of level of drug achieved in the colon and impact of agent on indigenous colonic flora. aIncludes C. bifermentans (1), C. innocuum (2), C. sordellii (1), and other Clostridium species (1). /Includes P. anaerobius (3), P. asaccharolyticus (4), P. magnus (3), P. micros (6), P. prevotii (3), P. tetradius (2), and other Peptostreptococcus species (2). JIncludes Actinomyces israelii (2), A. odontolyticus (5), Actinomyces species (1), Eubacteriumalactolyticum (1), E. lentum (3), E. limosum (2), Eubacterium species (1), Lactobacillus catenaformis (2), L. minutus (2), Lactobacillus species (1), and Propionibacterium acnes (4).

base-laked b l o o d agar (BLBA). Bacteroides gracilis strains w e r e tested on BLBA with fumarate and formate (0.3% each) a d d e d ; and Bilophila wadsworthia was tested o n BLBA w i t h p y r u v a t e (1%). Plates were incubated in an anaerobic c h a m b e r (Anaerobe Systems, San Jose, CA, USA) for 48 h at 37°C. MICs were defined according to NCCLS guidelines as the lowest concentration of antimicrobial agent producing a m a r k e d c h a n g e f r o m the g r o w t h c o n t r o l (NCCLS, 1993). R e f e r e n c e strains of B. fragilis [American T y p e Culture Collection (ATCC) 25285] and B. thetaiotaomicron (ATCC 29741) were used as controls in each test. Table 1 lists the in vitro susceptibility of vario u s g r o u p s of o r g a n i s m s to the a g e n t s t e s t e d . Grepafloxacin inhibited all strains of B. gracilis, B. wadsworthia, Clostridium perfringens, and Porphyromonas species at the b r e a k p o i n t or lower (-<2 ~g/ml). The other q u i n o l o n e s tested (ciprofloxacin and fieroxacin) also inhibited ~90% of isolates belonging to these species. Grepafloxacin d e m o n s t r a t e d substantially better activity against B. fragilis (83% susceptible) t h a n did either ciprofloxacin or fleroxacin (6% and 0, respectively) at 2 ~g/ml. O t h e r B. fragilis

g r o u p species w e r e inhibited to a greater extent at 4 p,g/ml by grepafloxacin (83% susceptible) than by ciprofloxacin or fleroxacin (20% and 18%, respectively). Ciprofloxacin had better activity against Fusobacterium and Prevotella species t h a n did either grepafloxacin or fleroxacin. Grepafloxacin was more active t h a n ciprofloxacin and fleroxacin against C. ramosum a n d Peptostreptococcus species. N o n e of the q u i n o l o n e s tested w e r e active against C. difficile. The overall activity of grepafloxacin against anaerobes was marginally better than that of tieroxacin a n d ciprofloxacin (59% vs 24% a n d 44%, respectively). O t h e r studies d o n e on limited n u m bers of anaerobes f o u n d similar results. One s t u d y r e p o r t e d MICg0s of 12.5, 50, a n d 0.78 ~g/ml for B. fragilis, C. difficile, a n d C. perfringens, respectively (Wakebe and Mitsuhashi, 1992); a n d a n o t h e r f o u n d MICg0s for B. fragilis and C. perfringens of 4 a n d 1 ~g/ml, r e s p e c t i v e l y ( N e u et al., 1992). O u r s t u d y f o u n d MICgo s for B. fragilis, C. difficile, and C. perfringens of 8, 32, and 2 ~g/ml, respectively. It is not yet clear w h e t h e r emerging resistance will be a p r o b l e m with t h e r a p y u s i n g fluoroqui-

Note

n o l o n e agents against anaerobic bacteria. Additional clinical trials are n e e d e d to ascertain h o w useful the more p o t e n t agents will be for t h e r a p y of mixed aerobic anaerobic infections.

133

This work was supported in part by VA Medical Research Merit Review Funds and in part by Otsuka America Pharmaceutical, Inc., Rockville, Maryland.

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(1992) Antimicrobial activity of DU-6859, a new potent fluoroquinolone, against clinical isolates. Antimicrob Agents Chemother 36:1491-1498. Summanen P, Baron EJ, Citron D, Strong C, Wexler HM, Finegold SM (1993) Wadsworth Anaerobic Bacteriology Manual. Belmont, CA: Star. Venezia RA, Yocum DM, Robbiano EM, Echols RM (1990) Comparative in vitro activities of a new quinolone, WIN 57273, and piperacillin plus tazobactam against anaerobic bacteria. Antimicrob Agents Chemother 34: 1858-1861. Wakebe H, Mitsuhashi S (1992) Comparative in vitro activities of a new quinolone, OPC-17116, possessing potent activity against Gram-positive bacteria. Antimicrob Agents Chemother 36:2185-2191. Wexler HM, Molitoris E, Finegold SM (1992) In vitro activities of three of the newer quinolones against anaerobic bacteria. Antimicrob Agents Chemother 36:239-243.