In vitro activity of DS-2969b and comparator antimicrobial agents against Clostridioides (Clostridium) difficile, methicillin-resistant Staphylococcus aureus, and other anaerobic bacteria.

The in vitro activity of DS-2969b, a novel GyrB inhibitor, and six comparator agents was studied against 101 recent North American Clostridioides difficile isolates, 46 other intestinal anaerobes and 51 strains of methicillin-resistant Staphylococcus aureus. The MIC ranges (MIC90s) of DS-2969b against C. difficile and S. aureus were 0.03-0.125 (0.125) µg/ml and 0.125-1 (0.5) µg/ml, respectively. DS-2969b showed the greatest activity of the agents tested. There was no difference in MICs of DS-2969b among different ribotypes.

In vitro activity of ceftaroline against 623 diverse strains of anaerobic bacteria.

The in vitro activities of ceftaroline, a novel, parenteral, broad-spectrum cephalosporin, and four comparator antimicrobials were determined against anaerobic bacteria. Against Gram-positive strains, the activity of ceftaroline was similar to that of amoxicillin-clavulanate and four to eight times greater than that of ceftriaxone. Against Gram-negative organisms, ceftaroline showed good activity against beta-lactamase-negative strains but not against the members of the Bacteroides fragilis group. Ceftaroline showed potent activity against a broad spectrum of anaerobes encountered in respiratory, skin, and soft tissue infections.

In vitro activities of tinidazole and metronidazole against Clostridium difficile, Prevotella bivia and Bacteroides fragilis.

Tinidazole, a 5-nitroimidazole similar to metronidazole, was studied against 40 Clostridium difficile, 10 Prevotella bivia and 11 Bacteroides fragilis clinical isolates. The geometric mean MICs of tinidazole and metronidazole were, respectively: C. difficile, 0.31 and 0.28 microg/mL; P. bivia, 2.33 and 1.52 microg/mL; B. fragilis, 0.5 and 0.71 microg/mL.

In vitro activities of ramoplanin, teicoplanin, vancomycin, linezolid, bacitracin, and four other antimicrobials against intestinal anaerobic bacteria.

By using an agar dilution method, the in vitro activities of ramoplanin, teicoplanin, vancomycin, linezolid, and five other agents were determined against 300 gram-positive and 54 gram-negative strains of intestinal anaerobes. Ramoplanin was active at or=256 microg/ml. Ramoplanin displays excellent activity against C. difficile and other gram-positive enteric anaerobes, including vancomycin-resistant strains; however, it has poor activity against most gram-negative anaerobes and thus potentially has a lesser effect on the ecological balance of normal fecal flora.

Bacteriology of human bite wound infections.

This study was designed to define the bacteriology of infected soft-tissue wounds from human bites, and to compare this with the bacteriology of infected animal bites in humans as determined in previous studies. The specimens were collected from 57 patients presenting to emergency rooms at 12 locations around the country. Three hundred and eighty organisms were isolated (224 aerobes and 156 anaerobes), for an average of 6.6 per specimen. The most prevalent anaerobes recovered were Prevotella spp. (34%), while streptococci comprised 44% of all aerobic organisms, over half of which were in the "Streptococcus milleri" group, particularly S. anginosus. The study demonstrated that the pathogens in human bite infections differ considerably from those present in animal bites.

Comparative in vitro activity of ertapenem and 11 other antimicrobial agents against aerobic and anaerobic pathogens isolated from skin and soft tissue animal and human bite wound infections.

We studied the comparative in vitro activity of ertapenem, a new carbapenem, against 240 aerobic and 180 anaerobic recent clinical bite isolates using an agar dilution method and an inoculum of 10(4) cfu/spot for aerobes and 10(5) cfu/spot for anaerobes. Ertapenem inhibited 410/420 (98%) of the isolates tested at < or = 4 mg/L with only 4/5 Campylobacter gracilis and 1/3 Campylobacter rectus strains requiring . or = 16 mg/L for inhibition. Ertapenem was only moderately active (MIC 8 mg/L) against 4/6 Enterococcus faecalis and 1/11 Staphylococcus epidermidis strains. All Pasteurella multocida, Pasteurella septica, Pasteurella canis, Pasteurella dagmatis, Moraxella spp. and EF-4 isolates were inhibited at < or = 0.015 mg/L. MIC(90)s for other aerobic genera and species were as follows: Corynebacterium spp., 4 mg/L; Staphylococcus aureus, 0.25 mg/L; Staphylococcus epidermidis, 4 mg/L; other coagulasenegative staphylococci, 0.25 mg/L; Streptococcus milleri group, 0.5 mg/L; Eikenella corrodens, 0.03 mg/L; and Bergeyella zoohelcum, 0.5 mg/L. For anaerobes the range of MICs and MIC(90)s were: Prevotella ssp., < or = 0.015-0.5, 0.125 mg/L; Porphyromonas spp., < or = 0.015-0.03, 0.015 mg/L; Fusobacterium spp., 0.015-0.125, 0.03 mg/L; Bacteroides tectum, 0.03-0.125, 0.125 mg/L; and Peptostreptococcus spp., 0.01-2, 1 mg/L. Ertapenem showed excellent potency against the full range of animal and human bite wound pathogens.

In vitro activities of ABT-773, a new ketolide, against aerobic and anaerobic pathogens isolated from antral sinus puncture specimens from patients with sinusitis.

The comparative in vitro activities of ABT-773 against 207 aerobic and 162 anaerobic antral sinus puncture isolates showed that erythromycin-resistant pneumococcal strains were susceptible to ABT-773 (< or =0.125 microg/ml); the MIC at which 90% of the isolates tested were inhibited for Haemophilus influenzae and other Haemophilus spp. was 4 microg/ml; and all Moraxella spp. and beta-lactamase-producing Prevotella species strains were inhibited by < or =0.125 microg/ml. Among the anaerobes tested, only fusobacteria (45%) required > or =4 microg of ABT-773/ml for inhibition. ABT-773 may offer a therapeutic alternative for sinus infections.

Comparative in vitro activities of GAR-936 against aerobic and anaerobic animal and human bite wound pathogens.

GAR-936 is a new semisynthetic glycylcycline with a broad antibacterial spectrum, including tetracycline-resistant strains. The in vitro activities of GAR-936, minocycline, doxycycline, tetracycline, moxifloxacin, penicillin G, and erythromycin were determined by agar dilution methods against 268 aerobic and 148 anaerobic strains of bacteria (including Pasteurella, Eikenella, Moraxella, Bergeyella, Neisseria, EF-4, Bacteroides, Prevotella, Porphyromonas, Fusobacterium, Staphylococcus, Streptococcus, Enterococcus, Corynebacterium, Propionibacterium, Peptostreptococcus, and Actinomyces) isolated from infected human and animal bite wounds in humans, including strains resistant to commonly used antimicrobials. GAR-936 was very active, with an MIC at which 90% of the strains are inhibited (MIC(90)) of < or =0.25 microg/ml, against all aerobic gram-positive and -negative strains, including tetracycline-resistant strains of Enterococcus, Streptococcus, and coagulase-negative staphylococci, except for Eikenella corrodens (MIC(90), < or =4 microg/ml). GAR-936 was also very active against all anaerobic species, including tetracycline-, doxycycline-, and minocycline-resistant strains of Prevotella spp., Porphyromonas spp., Bacteroides tectum, and Peptostreptococcus spp., with an MIC(90) of < or =0.25 microg/ml. Erythromycin- and moxifloxacin-resistant fusobacteria were susceptible to GAR-936, with an MIC(90) of 0.06 microg/ml.

Comparative in vitro activities of ABT-773 against aerobic and anaerobic pathogens isolated from skin and soft-tissue animal and human bite wound infections.

We studied the comparative in vitro activities of ABT-773, a new ketolide, against 268 aerobic and 148 anaerobic recent isolates from clinical bites using an agar dilution method and inocula of 10(4) CFU/spot for aerobes and 10(5) CFU for anaerobes. The following are the MIC ranges and MICs at which 90% of isolates are inhibited (MIC(90)s) of ABT-773 for various isolates, respectively: Pasteurella multocida and Pasteurella septica, 0.125 to 2 and 1 microg/ml; other Pasteurella species, 0.125 to 1 and 0.5 microg/ml; Corynebacterium spp., 0.015 to 0.06 and 0.015 microg/ml; Staphylococcus aureus, 0.03 to 0.06 and 0.06 microg/ml; coagulase-negative staphylococci, 0.015 to >32 and 32 microg/ml; streptococci, 0.015 to 0.03 and 0.03 microg/ml; Eikenella corrodens, 0.25 to 1 and 1 microg/ml; and Bergeyella zoohelcum, 0.03 to 0.25 and 0.06 microg/ml. For anaerobes the MIC ranges and MIC(90)s of ABT-773 were as follows, respectively: Prevotella heparinolytica, 0. 06 to 0.125 and 0.125 microg/ml; Prevotella spp., 0.015 to 0.125 and 0.06 microg/ml; Porphyromonas spp., 0.015 to 0.03 and 0.015 microg/ml; Fusobacterium nucleatum, 0.5 to 8 and 8 microg/ml; other Fusobacterium spp., 0.015 to 8 and 0.5 microg/ml; Bacteroides tectum, 0.015 to 0.5 and 0.06 microg/ml; and Peptostreptococcus spp., 0.015 to 0.25 and 0.03 microg/ml. ABT-773 was more active than all macrolides tested against S. aureus, E. corrodens, and anaerobes, but all compounds were poorly active against F. nucleatum. The activity of ABT-773 was within 1 dilution of that of azithromycin against Pasteurella spp., and ABT-773 was four- to eightfold more active than clarithromycin against Pasteurella spp. ABT-773 may offer a therapeutic alternative for bite wound infections.

Activities of telithromycin (HMR 3647, RU 66647) compared to those of erythromycin, azithromycin, clarithromycin, roxithromycin, and other antimicrobial agents against unusual anaerobes.

The comparative activity of telithromycin (HMR 3647) against 419 human anaerobic isolates was determined by the agar dilution method. At concentrations of

In vitro activity of gemifloxacin (SB 265805) against anaerobes.

Gemifloxacin mesylate (SB 265805), a new fluoronaphthyridone, was tested against 359 recent clinical anaerobic isolates by the National Committee for Clinical Laboratory Standards reference agar dilution method with supplemented brucella blood agar and an inoculum of 10(5) CFU/spot. Comparative antimicrobials tested included trovafloxacin, levofloxacin, grepafloxacin, sparfloxacin, sitafloxacin (DU-6859a), penicillin G, amoxicillin clavulanate, imipenem, cefoxitin, clindamycin, and metronidazole. The MIC(50) and MIC(90) (MICs at which 50 and 90% of the isolates were inhibited) of gemifloxacin against various organisms (with the number of strains tested in parentheses) were as follows (in micrograms per milliliter): for Bacteroides fragilis (28), 0.5 and 2; for Bacteroides thetaiotaomicron (24), 1 and 16; for Bacteroides caccae (12), 1 and 16; for Bacteroides distasonis (12), 8 and >16; for Bacteroides ovatus (12), 4 and >16; for Bacteroides stercoris (12), 0.5 and 0.5; for Bacteroides uniformis (12), 1 and 4; for Bacteroides vulgatus (11), 4 and 4; for Clostridium clostridioforme (15), 0.5 and 0.5; for Clostridium difficile (15), 1 and >16; for Clostridium innocuum (13), 0.125 and 2; for Clostridium perfringens (13), 0.06 and 0.06; for Clostridium ramosum (14), 0.25 and 8; for Fusobacterium nucleatum (12), 0.125 and 0.25; for Fusobacterium necrophorum (11), 0.25 and 0.5; for Fusobacterium varium (13), 0.5 and 1; for Fusobacterium spp. (12), 1 and 2; for Peptostreptococcus anaerobius (13), 0.06 and 0.06; for Peptostreptococcus asaccharolyticus (13), 0.125 and 0.125; for Peptostreptococcus magnus (14), 0.03 and 0.03; for Peptostreptococcus micros (12), 0.06 and 0.06; for Peptostreptococcus prevotii (14), 0.06 and 0.25; for Porphyromonas asaccharolytica (11), 0.125 and 0.125; for Prevotella bivia (10), 8 and 16; for Prevotella buccae (10), 2 and 2; for Prevotella intermedia (10), 0.5 and 0.5; and for Prevotella melaninogenica (11), 1 and 1. Gemifloxacin mesylate (SB 265805) was 1 to 4 dilutions more active than trovafloxacin against fusobacteria and peptostreptococci, and the two drugs were equivalent against clostridia and P. asaccharolytica. Gemifloxacin was equivalent to sitafloxacin (DU 6859a) against peptostreptococci, C. perfringens, and C. ramosum, and sitafloxacin was 2 to 3 dilutions more active against fusobacteria. Sparfloxacin, grepafloxacin, and levofloxacin were generally less active than gemifloxacin against all anaerobes.

Linezolid activity compared to those of selected macrolides and other agents against aerobic and anaerobic pathogens isolated from soft tissue bite infections in humans.

Linezolid was tested against 420 aerobes and anaerobes, including 148 Pasteurella isolates, by an agar dilution method. Linezolid was active against all Pasteurella multocida subsp. multocida and P. multocida subsp. septica isolates and most Pasteurella canis, Pasteurella dagmatis, and Pasteurella stomatis isolates. The MIC was

Activity of gatifloxacin compared to those of five other quinolones versus aerobic and anaerobic isolates from skin and soft tissue samples of human and animal bite wound infections.

The activity of gatifloxacin against 308 aerobes and 112 anaerobes isolated from bite wound infections was studied. Gatifloxacin was active at

Comparative in vitro activities of amoxicillin-clavulanate against aerobic and anaerobic bacteria isolated from antral puncture specimens from patients with sinusitis.

By an agar dilution method, the antimicrobial susceptibilities of antral sinus puncture isolates were studied. Pneumococci were generally susceptible to amoxicillin, azithromycin, and clarithromycin, but 17% of pneumococcal isolates were resistant to cefuroxime. Haemophilus influenzae isolates were resistant to amoxicillin and clarithromycin. beta-Lactamase production occurred in 69% of Prevotella species. One-third of Peptostreptococcus magnus isolates were resistant to azithromycin and clarithromycin. Cefuroxime had limited activity against Prevotella species and P. magnus. Levofloxacin was active against most isolates except peptostreptococci. Amoxicillin-clavulanate was active against all isolates, with the MIC at which 90% of the isolates were inhibited being < or = 1 microgram/ml.

Activities of HMR 3004 (RU 64004) and HMR 3647 (RU 66647) compared to those of erythromycin, azithromycin, clarithromycin, roxithromycin, and eight other antimicrobial agents against unusual aerobic and anaerobic human and animal bite pathogens isolated from skin and soft tissue infections in humans.

The activities of HMR 3004 and HMR 3647 and comparator agents, especially macrolides, were determined by the agar dilution method against 262 aerobic and 120 anaerobic strains isolated from skin and soft tissue infections associated with human and animal bite wounds. HMR 3004 and HMR 3647 were active against almost all aerobic and fastidious facultative isolates (MIC at which 90% of the isolates are inhibited [MIC90], < or = 0.5 and 1 microg/ml, respectively) and against all anaerobes [Bacteroides tectum, Porphyromonas macacae (salivosa), Prevotella heparinolytica, Porphyromonas sp., Prevotella sp., and peptostreptococci] at < or = 0.25 and < or = 0.5 microg/ml, respectively, except Fusobacterium nucleatum (HMR 3004, MIC90 = 16 microg/ml; HMR 3647, MIC90 = 8 microg/ml) and other Fusobacterium species (MIC90, 1 and 2 microg/ml, respectively). In general, HMR 3004 and HMR 3647 were more active than any of the macrolides tested. Azithromycin was more active than clarithromycin against all Pasteurella species, including Pasteurella multocida subsp. multocida, Eikenella corrodens, and Fusobacterium species, while clarithromycin was more active than azithromycin against Corynebacterium species, Weeksella zoohelcum, B. tectum, and P. heparinolytica.

Trovafloxacin compared with levofloxacin, ofloxacin, ciprofloxacin, azithromycin and clarithromycin against unusual aerobic and anaerobic human and animal bite-wound pathogens.

The activity of trovafloxacin and five other oral agents against 250 aerobic and 137 anaerobic strains isolated from human and animal bite wounds was determined by an agar dilution method. Trovafloxacin was active against all aerobic and fastidious facultative isolates at < or = 0.5 mg/L and all anaerobes at < or = 2 mg/L (Bacteroides tectum, Porphyromonas salivosa and Prevotella heparinolytica, < or = 0.25 mg/L; Porphyromonas spp., < or = 0.5 mg/L; Prevotella spp. and peptostreptococci, < or = 2.0 mg/L), except Fusobacterium nucleatum and other fusobacteria (MIC90 < or = 4 mg/L). Levofloxacin was generally one to two dilutions more active than ofloxacin, while ciprofloxacin was active against aerobes (MIC < or = 1 mg/L) but less active against anaerobic strains (MIC90 < or = 16 mg/L).

In vitro activity of Bay 12-8039, a new 8-methoxyquinolone, compared to the activities of 11 other oral antimicrobial agents against 390 aerobic and anaerobic bacteria isolated from human and animal bite wound skin and soft tissue infections in humans.

The in vitro activity of Bay 12-8039, a new oral 8-methoxyquinolone, was compared to the activities of 11 other oral antimicrobial agents (ciprofloxacin, levofloxacin, ofloxacin, sparfloxacin, azithromycin, clarithromycin, amoxicillin clavulanate, penicillin, cefuroxime, cefpodoxime, and doxycycline) against 250 aerobic and 140 anaerobic bacteria recently isolated from animal and human bite wound infections. Bay 12-8039 was active against all aerobic isolates, both gram-positive and gram-negative isolates, at < or = 1.0 microg/ml (MICs at which 90% of isolates are inhibited [MIC90s < or = 0.25 microg/ml) and was active against most anaerobes at < or = 0.5 microg/ml; the exceptions were Fusobacterium nucleatum and other Fusobacterium species (MIC90s, > or = 4.0 microg/ml) and one strain of Prevotella loeschii (MICs, 2.0 microg/ml). In comparison, the other quinolones tested had similar in vitro activities against the aerobic strains but were less active against the anaerobes, including peptostreptococci, Porphyromonas species, and Prevotella species. The fusobacteria were relatively resistant to all the antimicrobial agents tested except penicillin G (one penicillinase-producing strain of F. nucleatum was found) and amoxicillin clavulanate.

Comparative in vitro activities of DU-6859a, levofloxacin, ofloxacin, sparfloxacin, and ciprofloxacin against 387 aerobic and anaerobic bite wound isolates.

The activities of DU-6859a, levofloxacin, ofloxacin, sparfloxacin, and ciprofloxacin against bite wound isolates were determined by the agar dilution method. DU-6859a was the most active compound (MICs, < or = 0.125 microg/ml) against all Pasteurella species, Staphylococcus aureus, and streptococci; anaerobes were susceptible to < or = 0.5 microg/ml, except fusobacteria, which were susceptible to < or = 2 microg/ml. Against aerobes, levofloxacin was more active than ofloxacin (MIC at which 90% of isolates are inhibited [MIC90], < or = 1.0 microg/ml for both) and sparfloxacin and ciprofloxacin were also active (MIC90s, < or = 0.25 and < 1 microg/ml, respectively).