In Vitro Activity of AZD0914, a Novel Bacterial DNA Gyrase/Topoisomerase IV Inhibitor, against Clinically Relevant GramPositive and Fastidious Gram-Negative Pathogens Douglas J. Biedenbach,a Michael D. Huband,b* Meredith Hackel,a Boudewijn L. M. de Jonge,b Daniel F. Sahm,a Patricia A. Bradfordb International Health Management Associates, Inc., Schaumburg, Illinois, USAa; AstraZeneca Pharmaceuticals LP, Waltham, Massachusetts, USAb

AZD0914, a new spiropyrimidinetrione bacterial DNA gyrase inhibitor with a novel mode of inhibition, has activity against bacterial species commonly cultured from patient infection specimens, including fluoroquinolone-resistant isolates. This study assessed the in vitro activity of AZD0914 against key Gram-positive and fastidious Gram-negative clinical isolates collected globally in 2013. AZD0914 demonstrated potent activity, with MIC90s for AZD0914 of 0.25 mg/liter against Staphylococcus aureus (n ⴝ 11,680), coagulase-negative staphylococci (n ⴝ 1,923), streptococci (n ⴝ 4,380), and Moraxella catarrhalis (n ⴝ 145), 0.5 mg/liter against Staphylococcus lugdunensis (n ⴝ 120) and Haemophilus influenzae (n ⴝ 352), 1 mg/liter against Enterococcus faecalis (n ⴝ 1,241), and 2 mg/liter against Haemophilus parainfluenzae (n ⴝ 70). The activity against Enterococcus faecium was more limited (MIC90, 8 mg/liter). The spectrum and potency of AZD0914 included fluoroquinolone-resistant isolates in each species group, including methicillin-resistant staphylococci, penicillin-resistant streptococci, vancomycin-resistant enterococci, ␤-lactamase-producing Haemophilus spp., and M. catarrhalis. Based on these in vitro findings, AZD0914 warrants further investigation for its utility against a variety of Gram-positive and fastidious Gram-negative bacterial species.

F

ollowing the introduction of nalidixic acid into clinical practice in the 1960s, fluoroquinolones have undergone profound structural modifications, leading to the development of numerous molecules in this class (1–3). Modifications to the quinolone structure, particularly the addition of fluorine(s) at key positions, have provided compounds with increased potency, broader spectrum of activity, and acceptable safety profiles. However, safety has been problematic in fluoroquinolone development (4–6). Several potent compounds have either been determined to be unsuitable for human use due to unacceptable toxicities, have required black box warnings on their labels, have been restricted to topical applications, or have resulted in removal from the market (7–9). Resistance development to fluoroquinolones is also becoming a significant concern among several Gram-positive and Gramnegative pathogens, including Staphylococcus aureus, Escherichia coli, and Neisseria gonorrhoeae. AZD0914 is a new orally administered spiropyrimidinetrione bacterial DNA gyrase inhibitor that demonstrates a novel mode of inhibition distinct from that of fluoroquinolones (10, 11). AZD0914 is a selective and potent inhibitor of the supercoiling and decatenation activity of DNA gyrase and topoisomerase IV, with the ability to overcome fluoroquinolone resistance by the inhibition of DNA biosynthesis through the accumulation of double-stranded cleaved DNA bound to the tetramer topoisomerase II. AZD0914 has a primary spectrum of activity that includes clinically relevant Gram-positive and fastidious Gram-negative bacterial species, including N. gonorrhoeae (12–15). Published in vitro data on Chlamydia trachomatis and Chlamydia pneumoniae have shown that AZD0914 also has activity against these species (16). Its activity is maintained against strains with common fluoroquinolone resistance mutations in gyrase and topoisomerase IV within the quinolone resistance-determining region (QRDR) (12). Resistance to other key antimicrobial classes, such as ␤-lactams, macrolides, and glycopeptides, also do not diminish the

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activity of AZD0914. Currently, AZD0914 is being investigated in phase 2 trials for the treatment of uncomplicated N. gonorrhoeae infections (14, 15). In this study, the in vitro activity of AZD0914 against key bacterial groups isolated from intra-abdominal, urinary tract, skin and soft tissue, and respiratory tract infections collected in a 2013 global surveillance survey was analyzed and compared to that of levofloxacin, moxifloxacin, and other nonfluoroquinolone compounds. (This study was presented, in part, at the 54th Interscience Conference on Antimicrobial Agents and Chemotherapy in 2014 [12].) MATERIALS AND METHODS Clinical isolates (n ⫽ 21,152) from hospitalized patients were collected at 169 medical centers in 39 countries distributed across North America, Latin America, Europe, Asia-Pacific, and Middle East/Africa during 2013. Isolates were obtained from specimens collected from patients with documented intra-abdominal infections (IAI), urinary tract infections (UTI), skin and soft tissue infections (SSTI), or lower respiratory tract infections (LRTI). Only one isolate per patient infection episode was included in the surveillance program. Confirmation of isolate identification to the species

Received 28 April 2015 Returned for modification 11 June 2015 Accepted 12 July 2015 Accepted manuscript posted online 20 July 2015 Citation Biedenbach DJ, Huband MD, Hackel M, de Jonge BLM, Sahm DF, Bradford PA. 2015. In vitro activity of AZD0914, a novel bacterial DNA gyrase/topoisomerase IV inhibitor, against clinically relevant Gram-positive and fastidious Gram-negative pathogens. Antimicrob Agents Chemother 59:6053– 6063. doi:10.1128/AAC.01016-15. Address correspondence to Douglas J. Biedenbach, [email protected]. * Present address: Michael D. Huband, JMI Laboratories, North Liberty, Iowa, USA. Copyright © 2015, American Society for Microbiology. All Rights Reserved. doi:10.1128/AAC.01016-15

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TABLE 1 Activity of AZD0914 and comparator agents tested against Staphylococcus species Organism/phenotype (no. of isolates) S. aureus All (11,680)

MSSA (5,014)

MRSA (6,666)

Levofloxacin susceptible (6,668)

Levofloxacin resistant (4,971)

S. lugdunensis (120)

CLSI susceptibilitya Drug

MIC range

MIC50

MIC90

% Sus

% Int

% Res

AZD0914 Levofloxacin Moxifloxacin Oxacillin Erythromycin Clindamycin Linezolid Daptomycin Minocycline Tigecycline Vancomycin AZD0914 Levofloxacin Moxifloxacin Oxacillin Erythromycin Clindamycin Linezolid Daptomycin Minocycline Tigecycline Vancomycin AZD0914 Levofloxacin Moxifloxacin Oxacillin Erythromycin Clindamycin Linezolid Daptomycin Minocycline Tigecycline Vancomycin AZD0914 Levofloxacin Moxifloxacin Oxacillin Erythromycin Clindamycin Linezolid Daptomycin Minocycline Tigecycline Vancomycin AZD0914 Levofloxacin Moxifloxacin Oxacillin Erythromycin Clindamycin Linezolid Daptomycin Minocycline Tigecycline Vancomycin

ⱕ0.008 to 1 ⱕ0.015 to ⬎2 ⱕ0.03 to ⬎2 ⱕ0.06 to ⬎2 ⱕ0.12 to ⬎4 ⱕ0.03 to ⬎2 ⱕ0.5 to ⬎8 ⱕ0.06 to ⬎2 ⱕ0.12 to ⬎8 0.03 to ⬎2 ⱕ0.25 to 2 ⱕ0.008 to 1 ⱕ0.015 to ⬎2 ⱕ0.03 to ⬎2 ⱕ0.06 to 2 ⱕ0.12 to ⬎4 ⱕ0.03 to ⬎2 ⱕ0.5 to 4 ⱕ0.06 to ⬎2 ⱕ0.12 to ⬎8 0.03 to 2 ⱕ0.25 to 2 0.03 to 0.5 0.03 to ⬎2 ⱕ0.03 to ⬎2 ⬎2 to ⬎2 ⱕ0.12 to ⬎4 ⱕ0.03 to ⬎2 ⱕ0.5 to ⬎8 0.12 to ⬎2 ⱕ0.12 to ⬎8 0.03 to ⬎2 ⱕ0.25 to 2 ⱕ0.008 to 0.5 ⱕ0.015 to 1 ⱕ0.03 to ⬎2 ⱕ0.06 to ⬎2 ⱕ0.12 to ⬎4 ⱕ0.03 to ⬎2 ⱕ0.5 to 4 ⱕ0.06 to ⬎2 ⱕ0.12 to ⬎8 0.03 to 2 ⱕ0.25 to 2 0.03 to 1 ⬎2 ⱕ0.03 to ⬎2 ⱕ0.06 to ⬎2 ⱕ0.12 to ⬎4 ⱕ0.03 to ⬎2 ⱕ0.5 to ⬎8 0.12 to ⬎2 ⱕ0.12 to ⬎8 0.03 to ⬎2 ⱕ0.25 to 2

0.12 0.5 0.12 ⬎2 1 0.12 2 0.5 ⱕ0.12 0.12 1 0.12 0.25 0.06 0.5 0.5 0.12 2 0.5 ⱕ0.12 0.12 1 0.12 ⬎2 2 ⬎2 ⬎4 0.12 2 0.5 ⱕ0.12 0.12 1 0.12 0.25 0.06 0.5 0.5 0.12 2 0.5 ⱕ0.12 0.12 1 0.12 ⬎2 ⬎2 ⬎2 ⬎4 1 2 1 ⱕ0.12 0.12 1

0.25 ⬎2 ⬎2 ⬎2 ⬎4 ⬎2 2 1 2 0.25 1 0.25 0.5 0.12 0.5 ⬎4 0.12 2 1 0.5 0.25 1 0.25 ⬎2 ⬎2 ⬎2 ⬎4 ⬎2 2 1 8 0.5 1 0.25 0.5 0.12 ⬎2 ⬎4 0.25 2 1 0.5 0.25 1 0.25 ⬎2 ⬎2 ⬎2 ⬎4 ⬎2 2 1 8 0.5 1

NAb 57.1 57.3 42.9 46.6 74.9 100 99.4 93.0 97.8 100 NA 93.2 93.4 100 73.5 95.0 100 99.6 99.0 99.2 100 NA 29.9 30.1 0.0 26.3 59.8 100 99.3 88.5 96.8 100 NA 100 99.9 70.1 68.3 93.6 100 99.7 98.4 99.2 100 NA 0.0 0.2 6.5 17.5 50.0 100 99.0 85.8 96.0 100

NA 0.3 2.2 0.0 5.4 0.4 0.0 0.0 4.2 0.0 0.0 NA 0.3 0.9 0.0 7.4 0.3 0.0 0.0 0.6 0.0 0.0 NA 0.4 3.2 0.0 3.9 0.4 0.0 0.0 6.9 0.0 0.0 NA 0.0 0.0 0.0 7.0 0.3 0.0 0.0 0.8 0.0 0.0 NA 0.0 4.8 0.0 3.3 0.3 0.0 0.0 8.7 0.0 0.0

NA 42.6 40.5 57.1 48.0 24.7 0.0 0.6 2.8 2.2 0.0 NA 6.5 5.7 0.0 19.0 4.7 0.0 0.4 0.4 0.8 0.0 NA 69.7 66.7 100 69.8 39.8 0.0 0.8 4.6 3.2 0.0 NA 0.0 0.1 29.9 24.8 6.1 0.0 0.3 0.8 0.8 0.0 NA 100 95.0 93.5 79.1 49.7 0.0 1.0 5.5 4.0 0.0

AZD0914 Levofloxacin Moxifloxacin

0.12 to 1 0.12 to 0.5 0.06 to 0.25

0.5 0.25 0.12

0.5 0.5 0.12

NA 100 100

NA 0.0 0.0

NA 0.0 0.0

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AZD0914 In Vitro Activity

TABLE 1 (Continued) Organism/phenotype (no. of isolates)

CoNS All (1,923)

Levofloxacin susceptible (963)

Levofloxacin resistant (930)

a b

CLSI susceptibilitya Drug

MIC range

MIC50

MIC90

% Sus

% Int

% Res

Oxacillin Erythromycin Clindamycin Linezolid Daptomycin Minocycline Tigecycline Vancomycin

0.12 to ⬎2 ⱕ0.12 to ⬎4 ⱕ0.03 to ⬎2 ⱕ0.5 to 2 ⱕ0.06 to 1 ⱕ0.12 to 8 0.03 to 0.25 ⱕ0.25 to 2

1 ⱕ0.12 0.06 1 0.5 ⱕ0.12 0.06 1

2 ⬎4 ⬎2 1 0.5 0.25 0.12 1

95.8 78.3 89.2 100 100 98.3 100 100

0.0 0.0 0.0 0.0 0.0 1.7 0.0 0.0

4.2 21.7 10.8 0.0 0.0 0.0 0.0 0.0

AZD0914 Levofloxacin Moxifloxacin Oxacillin Erythromycin Clindamycin Linezolid Daptomycin Minocycline Tigecycline Vancomycin AZD0914 Levofloxacin Moxifloxacin Oxacillin Erythromycin Clindamycin Linezolid Daptomycin Minocycline Tigecycline Vancomycin AZD0914 Levofloxacin Moxifloxacin Oxacillin Erythromycin Clindamycin Linezolid Daptomycin Minocycline Tigecycline Vancomycin

0.015 to 2 ⱕ0.015 to ⬎2 ⱕ0.03 to ⬎2 ⱕ0.06 to ⬎2 ⱕ0.12 to ⬎4 ⱕ0.03 to ⬎2 ⱕ0.5 to ⬎8 ⱕ0.06 to ⬎2 ⱕ0.12 to ⬎8 ⱕ0.015 to 2 ⱕ0.25 to 4 0.015 to 1 ⱕ0.015 to 1 ⱕ0.03 to ⬎2 ⱕ0.06 to ⬎2 ⱕ0.12 to ⬎4 ⱕ0.03 to ⬎2 ⱕ0.5 to 4 ⱕ0.06 to ⬎2 ⱕ0.12 to ⬎8 ⱕ0.015 to 2 ⱕ0.25 to 4 0.03 to 2 ⬎2 0.5 to ⬎2 ⱕ0.06 to ⬎2 ⱕ0.12 to ⬎4 ⱕ0.03 to ⬎2 ⱕ0.5 to ⬎8 0.12 to 2 ⱕ0.12 to ⬎8 0.03 to 2 ⱕ0.25 to 4

0.12 1 0.5 ⬎2 ⬎4 0.12 1 1 0.25 0.25 2 0.12 0.25 0.06 0.5 4 0.06 1 0.5 ⱕ0.12 0.12 1 0.12 ⬎2 2 ⬎2 ⬎4 ⬎2 1 1 0.25 0.25 2

0.25 ⬎2 ⬎2 ⬎2 ⬎4 ⬎2 2 1 1 0.5 2 0.25 0.5 0.12 ⬎2 ⬎4 ⬎2 2 1 0.5 0.5 2 0.25 ⬎2 ⬎2 ⬎2 ⬎4 ⬎2 2 1 1 0.5 2

NA 50.1 50.8 26.0 32.7 65.9 99.6 99.0 98.8 97.4 100 NA 100 99.8 47.7 49.3 85.3 100 98.7 99.4 98.3 100 NA 0.0 0.4 4.5 15.8 46.3 99.1 99.4 98.4 96.6 100

NA 1.6 14.9 0.0 0.8 2.0 0.0 0.0 0.7 0.0 0.0 NA 0.0 0.0 0.0 1.0 3.3 0.0 0.0 0.5 0.0 0.0 NA 0.0 29.0 0.0 0.5 0.7 0.0 0.0 0.8 0.0 0.0

NA 48.4 34.3 74.0 66.5 32.1 0.4 1.0 0.5 2.6 0.0 NA 0.0 0.2 52.3 49.6 11.4 0.0 1.4 0.1 1.7 0.0 NA 100 70.5 95.5 83.7 53.0 0.9 0.7 0.9 3.4 0.0

CLSI susceptibilities defined by CLSI document M100-S24 (18). Sus, susceptible; Int, intermediate; Res, resistant. NA, no breakpoint criteria available.

level was done using matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry (Bruker Daltonics, Bremen, Germany); susceptibility testing by broth microdilution, according to current CLSI guidelines (17–19), was both performed at a central laboratory (International Health Management Associates [IHMA], Inc., Schaumburg, IL). Of the 21,152 isolates collected, the percentage of isolates per region was Europe, 48.5%; Asia-Pacific, 21.5%; North America, 11.1%; Latin America, 10.9%; and Middle East/Africa, 8.0%. The source of the organisms by infection type included IAI, 7.6%; LRTI, 31.3%; SSTI, 53.1%; UTI, 7.8%; and unknown source or not given, 0.2%. MICs were determined using custom frozen broth microdilution panels prepared at IHMA, Inc. All broth microdilution testing aspects, including panel manufacture, inoculation, incubation, and interpretation, were conducted according to current CLSI guidelines (17–19). The in vitro

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activities of levofloxacin, moxifloxacin, and other compounds were tested concurrently used as comparator agents to AZD0914. The activity of AZD0914 was analyzed against susceptible and resistant populations for comparative purposes where appropriate. Quality control testing (QC) using appropriate ATCC strains was performed on each day of testing, according to CLSI guidelines (17). The QC ranges for AZD0914 have been approved by the CLSI and are documented in the June 2014 CLSI antimicrobial susceptibility testing meeting minutes (http://clsi.org/standards /micro/microbiology-files/).

RESULTS

The in vitro activity of AZD0914 and comparator antibiotics was determined against 11,680 isolates of S. aureus (Table 1). These

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TABLE 2 Activity of AZD0914 and comparator agents tested against Streptococcus species Organism/phenotype (no. of isolates) S. pneumoniae All (2,324)

Penicillin susceptible (2,059)

Penicillin intermediate (208)

Penicillin resistant (57)

Erythromycin susceptible (1,445)

Erythromycin susceptible (874)

CLSI susceptibilitya Drug

MIC range

MIC50

MIC90

% Sus

% Int

% Res

AZD0914 Levofloxacin Moxifloxacin Penicillin Ceftriaxone Erythromycin Clindamycin Linezolid Tigecycline Vancomycin AZD0914 Levofloxacin Moxifloxacin Penicillin Ceftriaxone Erythromycin Clindamycin Linezolid Tigecycline Vancomycin AZD0914 Levofloxacin Moxifloxacin Penicillin Ceftriaxone Erythromycin Clindamycin Linezolid Tigecycline Vancomycin AZD0914 Levofloxacin Moxifloxacin Penicillin Ceftriaxone Erythromycin Clindamycin Linezolid Tigecycline Vancomycin AZD0914 Levofloxacin Moxifloxacin Penicillin Ceftriaxone Erythromycin Clindamycin Linezolid Tigecycline Vancomycin AZD0914 Levofloxacin Moxifloxacin Penicillin Ceftriaxone Erythromycin Clindamycin Linezolid

ⱕ0.015 to 0.5 0.12 to ⬎8 ⱕ0.03 to ⬎4 ⱕ0.015 to ⬎8 ⱕ0.015 to ⬎4 ⱕ0.008 to ⬎1 ⱕ0.008 to ⬎1 ⱕ0.06 to 2 ⱕ0.008 to ⬎1 ⱕ0.008 to 1 ⱕ0.015 to 0.5 ⱕ0.12 to ⬎8 ⱕ0.03 to ⬎4 ⱕ0.015 to 2 ⱕ0.015 to ⬎4 ⱕ0.008 to ⬎1 ⱕ0.008 to ⬎1 ⱕ0.06 to 2 ⱕ0.008 to 0.12 ⱕ0.008 to 1 0.12 to 0.5 ⱕ0.12 to ⬎8 0.06 to ⬎4 4 to 4 ⱕ0.015 to ⬎4 0.015 to ⬎1 0.015 to ⬎1 0.25 to 2 ⱕ0.008 to 0.06 0.06 to 1 0.06 to 0.25 ⱕ0.12 to ⬎8 0.06 to ⬎4 8 to ⬎8 ⱕ0.015 to ⬎4 0.06 to ⬎1 0.03 to ⬎1 0.5 to 2 ⱕ0.008 to ⬎1 0.12 to 0.5 ⱕ0.015 to 0.5 ⱕ0.12 to ⬎8 ⱕ0.03 to ⬎4 ⱕ0.015 to 8 ⱕ0.015 to ⬎4 ⱕ0.008 to 0.25 ⱕ0.008 to ⬎1 ⱕ0.06 to 2 ⱕ0.008 to 0.12 ⱕ0.008 to 1 0.03 to 0.5 ⱕ0.12 to ⬎8 ⱕ0.03 to ⬎4 ⱕ0.015 to ⬎8 ⱕ0.015 to ⬎4 1 to ⬎1 ⱕ0.008 to ⬎1 0.25 to 2

0.12 1 0.12 0.06 0.03 0.06 0.06 1 0.03 0.25 0.12 1 0.12 0.06 0.03 0.06 0.06 1 0.03 0.25 0.12 1 0.12 4 2 ⬎1 ⬎1 1 0.03 0.25 0.25 1 0.12 8 4 ⬎1 ⬎1 1 0.03 0.5 0.12 1 0.12 0.03 0.03 0.06 0.06 1 0.03 0.25 0.12 1 0.12 2 0.5 ⬎1 ⬎1 1

0.25 2 0.12 4 2 ⬎1 ⬎1 2 0.03 0.5 0.25 2 0.12 2 1 ⬎1 ⬎1 2 0.03 0.5 0.25 2 0.12 4 4 ⬎1 ⬎1 2 0.03 0.5 0.25 4 2 ⬎8 ⬎4 ⬎1 ⬎1 1 0.03 0.5 0.25 2 0.12 0.5 0.25 0.06 0.06 2 0.03 0.5 0.25 2 0.12 4 2 ⬎1 ⬎1 1

NAb 98.4 98.8 88.6 89.6 62.2 72.5 100 99.7 100 NA 99.0 99.3 100 97.0 68.3 77.9 100 99.7 100 NA 94.7 97.1 0.0 38.9 17.8 34.1 100 100 100 NA 89.5 89.5 0.0 5.3 1.8 17.5 100 98.3 100 NA 99.7 99.8 97.4 98.8 100 99.9 100 99.7 100 NA 96.3 97.3 74.1 74.5 0.0 27.5 100

NA 0.3 0.4 9.0 7.8 0.2 0.1 0.0 0.0 0.0 NA 0.2 0.3 0.0 2.8 0.2 0.1 0.0 0.0 0.0 NA 1.0 0.5 100 47.6 0.0 0.0 0.0 0.0 0.0 NA 1.8 3.5 0.0 43.9 1.8 0.0 0.0 0.0 0.0 NA 0.1 0.1 2.6 1.0 0.0 0.1 0.0 0.0 0.0 NA 0.7 0.9 19.6 19.0 0.0 0.1 0.0

NA 1.3 0.8 2.5 2.6 37.6 27.4 0.0 0.3 0.0 NA 0.7 0.4 0.0 0.2 31.5 22.0 0.0 0.3 0.0 NA 4.3 2.4 0.0 13.5 82.2 65.9 0.0 0.0 0.0 NA 8.8 7.0 100 50.9 96.5 82.5 0.0 1.8 0.0 NA 0.2 0.1 0.1 0.2 0.0 0.1 0.0 0.3 0.0 NA 3.0 1.8 6.3 6.5 100 72.4 0.0

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AZD0914 In Vitro Activity

TABLE 2 (Continued) Organism/phenotype (no. of isolates)

Levofloxacin nonsusceptible (37)

␤-Hemolytic streptococci All (2,056)

S. pyogenes (1,358)

S. agalactiae (441)

S. dysgalactiae (257)

Levofloxacin nonsusceptible (50)

CLSI susceptibilitya Drug

MIC range

MIC50

MIC90

% Sus

% Int

% Res

Tigecycline Vancomycin AZD0914 Levofloxacin Moxifloxacin Penicillin Ceftriaxone Erythromycin Clindamycin Linezolid Tigecycline Vancomycin

ⱕ0.008 to ⬎1 0.06 to 1 0.06 to 0.5 4 to ⬎8 0.12 to 4 ⱕ0.015 to ⬎8 ⱕ0.015 to ⬎4 0.03 to ⬎1 0.06 to ⬎1 0.25 to 2 ⱕ0.008 to 0.03 0.06 to 0.5

0.03 0.25 0.12 ⬎8 2 2 1 ⬎1 ⬎1 1 0.03 0.5

0.03 0.5 0.25 ⬎8 ⬎4 2 1 ⬎1 ⬎1 1 0.03 0.5

99.7 100 NA 0.0 29.7 54.1 64.9 13.5 32.4 100 100 100

0.0 0.0 NA 21.6 21.6 29.7 13.5 0.0 0.0 0.0 0.0 0.0

0.3 0.0 NA 78.4 48.7 16.2 21.6 86.5 67.6 0.0 0.0 0.0

AZD0914 Levofloxacin Moxifloxacin Penicillin Ceftriaxone Erythromycin Clindamycin Linezolid Tigecycline Vancomycin AZD0914 Levofloxacin Moxifloxacin Penicillin Ceftriaxone Erythromycin Clindamycin Linezolid Tigecycline Vancomycin AZD0914 Levofloxacin Moxifloxacin Penicillin Ceftriaxone Erythromycin Clindamycin Linezolid Tigecycline Vancomycin AZD0914 Levofloxacin Moxifloxacin Penicillin Ceftriaxone Erythromycin Clindamycin Linezolid Tigecycline Vancomycin AZD0914 Levofloxacin Moxifloxacin Penicillin Ceftriaxone Erythromycin

ⱕ0.015 to 0.5 ⱕ0.12 to ⬎8 ⱕ0.03 to ⬎4 ⱕ0.015 to 2 ⱕ0.015 to 1 ⱕ0.008 to ⬎1 ⱕ0.008 to ⬎1 ⱕ0.06 to 2 ⱕ0.008 to 0.5 ⱕ0.008 to 1 ⱕ0.015 to 0.5 ⱕ0.12 to 4 ⱕ0.03 to ⬎4 ⱕ0.015 to 0.12 ⱕ0.015 to 0.5 0.015 to ⬎1 ⱕ0.008 to ⬎1 0.12 to 2 ⱕ0.008 to 0.25 ⱕ0.008 to 1 0.03 to 0.5 ⱕ0.12 to ⬎8 ⱕ0.03 to ⬎4 0.03 to 0.5 ⱕ0.015 to 1 0.015 to ⬎1 0.03 to ⬎1 0.25 to 2 0.015 to 0.12 0.03 to 1 ⱕ0.015 to 0.5 ⱕ0.12 to ⬎8 0.06 to 4 ⱕ0.015 to 2 ⱕ0.015 to 0.25 ⱕ0.008 to ⬎1 ⱕ0.008 to ⬎1 ⱕ0.06 to 2 0.015 to 0.5 ⱕ0.008 to 1 0.06 to 0.5 4 to ⬎8 0.25 to ⬎4 ⱕ0.015 to 0.5 ⱕ0.015 to 1 0.03 to ⬎1

0.12 1 0.12 0.03 0.03 0.06 0.06 1 0.03 0.5 0.12 1 0.12 0.03 0.03 0.06 0.06 1 0.03 0.5 0.12 1 0.12 0.06 0.06 0.06 0.06 1 0.03 0.5 0.12 1 0.12 0.03 0.03 0.06 0.06 1 0.03 0.25 0.12 ⬎8 4 0.06 0.06 0.06

0.25 2 0.25 0.12 0.06 ⬎1 0.5 2 0.06 0.5 0.25 1 0.25 0.03 0.03 ⬎1 0.06 2 0.06 0.5 0.25 2 0.25 0.12 0.12 ⬎1 ⬎1 2 0.06 0.5 0.25 1 0.25 0.03 0.06 ⬎1 1 2 0.12 0.5 0.25 ⬎8 ⬎4 0.12 0.12 ⬎1

NA 97.6 NA 99.9 100 83.0 89.9 100 100 100 NA 99.1 NA 100 100 89.0 93.8 100 100 100 NA 91.8 NA 99.8 99.8 66.7 78.5 100 100 100 NA 99.2 NA 99.2 100 79.8 89.1 100 99.6 100 NA 0.0 NA 98.0 98.0 58.0

NA 0.6 NA 0.0 0.0 0.3 0.3 0.0 0.0 0.0 NA 0.9 NA 0.0 0.0 0.0 0.1 0.0 0.0 0.0 NA 0.2 NA 0.0 0.0 1.1 0.9 0.0 0.0 0.0 NA 0.0 NA 0.0 0.0 0.4 0.8 0.0 0.0 0.0 NA 26.0 NA 0.0 0.0 2.0

NA 1.8 NA 0.1 0.0 16.7 9.7 0.0 0.1 0.0 NA 0.0 NA 0.0 0.0 11.1 6.1 0.0 0.0 0.0 NA 7.9 NA 0.2 0.2 32.2 20.6 0.0 0.0 0.0 NA 0.8 NA 0.8 0.0 19.8 10.1 0.0 0.4 0.0 NA 74.0 NA 2.0 2.0 40.0

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TABLE 2 (Continued) Organism/phenotype (no. of isolates)

Viridans streptococci (296)

a b

CLSI susceptibilitya Drug

MIC range

MIC50

MIC90

% Sus

% Int

% Res

Clindamycin Linezolid Tigecycline Vancomycin AZD0914 Levofloxacin Moxifloxacin Penicillin Ceftriaxone Erythromycin Clindamycin Linezolid Tigecycline Vancomycin

0.03 to ⬎1 0.25 to 2 0.015 to 0.06 0.25 to 0.5 ⱕ0.015 to 0.5 ⱕ0.12 to ⬎8 ⱕ0.03 to ⬎4 ⱕ0.015 to ⬎8 ⱕ0.015 to ⬎4 0.015 to ⬎1 ⱕ0.008 to ⬎1 0.12 to 2 ⱕ0.008 to 0.5 ⱕ0.008 to ⬎1

0.06 1 0.03 0.5 0.12 1 0.12 0.06 0.12 0.06 0.03 1 0.03 0.5

⬎1 2 0.06 0.5 0.25 2 0.25 0.25 0.5 ⬎1 ⬎1 2 0.12 1

72.0 100 100 100 NA 97.0 NA 88.9 98.3 65.5 81.1 100 98.7 99.7

0.0 0.0 0.0 0.0 NA 1.4 NA 8.8 0.7 0.7 0.0 0.0 0.0 0.0

28.0 0.0 0.0 0.0 NA 1.7 NA 2.4 1.0 33.8 18.9 0.0 1.4 0.3

CLSI susceptibilities defined by CLSI document M100-S24 (18). Sus, susceptible; Int, intermediate; Res, resistant. NA, no breakpoint criteria available.

included methicillin-susceptible S. aureus (MSSA), methicillinresistant S. aureus (MRSA), levofloxacin-susceptible (MIC, ⱕ1 mg/liter), and levofloxacin-resistant (MIC, ⱖ4 mg/liter) isolates. The MIC90 of AZD0914 against S. aureus was 0.25 mg/liter, with equal potency against MRSA and MSSA. In contrast, the MIC90 of both levofloxacin and moxifloxacin was ⬎2 mg/liter for S. aureus. Whereas 93.2% of the MSSA isolates were susceptible to levofloxacin (MIC90, 0.5 mg/liter), only 29.9% of the MRSA isolates were levofloxacin susceptible. Levofloxacin susceptibility did not affect the activity of AZD0914, with MIC90s of 0.25 mg/liter against both levofloxacin-susceptible and -resistant isolates. One levofloxacin-resistant MSSA isolate collected in Europe resulted in an AZD0914 MIC of 1 mg/liter. Regardless of specimen source or geographic source, no major differences were observed in the activity of AZD0914 against S. aureus (data not shown). AZD0914 and comparator antibiotics were tested against 1,923 coagulase-negative staphylococci (CoNS) (Table 1), including methicillin-susceptible, methicillin-resistant (74% of the isolates), levofloxacin-susceptible, and levofloxacin-resistant isolates. The overall MIC90 of AZD0914 against CoNS was 0.25 mg/liter, which was ⱖ16fold lower than that for levofloxacin and moxifloxacin (both MIC90, ⬎2 mg/liter). There was no change in the MIC90s of AZD0914 when the population was segregated according to their methicillin resistance status (data not shown), but the levofloxacin MIC90s against the methicillin-susceptible and methicillin-resistant CoNS isolates were 0.5 and ⬎2 mg/liter, respectively. Resistance to levofloxacin did not affect the activity of AZD0914 (Table 1). The AZD0914 MIC90 against the CoNS collected from each of the five geographic regions was identical, at 0.25 mg/liter. The in vitro activities of AZD0914 and comparator antibiotics specifically against 120 isolates of Staphylococcus lugdunensis are also shown in Table 1. The MIC90 of AZD0914 (0.5 mg/liter) against S. lugdunensis was 2-fold higher than that against S. aureus. All isolates were susceptible to levofloxacin and moxifloxacin, with MIC90s of 0.5 mg/liter and 0.12 mg/liter, respectively. The in vitro activities of AZD0914 and comparators against S. pneumoniae, including penicillin-susceptible and nonsusceptible isolates, are shown in Table 2. The overall MIC90 of AZD0914 against S. pneumoniae was 0.25 mg/liter and, unlike levofloxacin

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and moxifloxacin, the activity of AZD0914 was not affected by the penicillin resistance status of the population tested. All of the isolates had AZD0914 MICs of ⱕ0.5 mg/liter, with 99.4% of them being ⱕ0.25 mg/liter. Among the isolate collection, 37.6% were erythromycin resistant, and AZD0914 MICs were not affected by resistance to macrolides (Table 2). Regardless of specimen or geographical source, no major differences were observed in the activity of AZD0914 against isolates of S. pneumoniae (data not shown). The in vitro activities of AZD0914 and comparator antibiotics against ␤-hemolytic streptococci (␤HS) and viridans streptococci also are shown in Table 2. The MIC90s obtained with AZD0914 and moxifloxacin were 0.25 mg/liter for all species. Against these same species, levofloxacin was 4- to 8-fold less active, with MIC90s of 1 to 2 mg/liter. The potency of AZD0914 against the ␤HS did not differ between the species tested or across the five geographic regions. Of the 1,358 Streptococcus pyogenes isolates tested, 11% were erythromycin resistant, and AZD0914 was equally active against these subpopulations, with only 4 isolates (2 erythromycin susceptible and 2 erythromycin resistant) having an AZD0914 MIC of 0.5 mg/liter (data not shown). The activity of AZD0914 was also similar against erythromycin-susceptible and erythromycin-resistant (32.2%) Streptococcus agalactiae isolates, with MIC90s of 0.25 mg/liter (data not shown). In contrast, whereas levofloxacin was effective against the erythromycin-susceptible isolates (MIC90, 2 mg/liter; 94.2% susceptible), its activity was decreased against the erythromycin-resistant S. agalactiae isolates (MIC90, ⬎8 mg/liter; 87.3% susceptible). Isolates of erythromycin-resistant ␤-hemolytic streptococci (610 isolates) showed a lower MIC90 with AZD0914 and moxifloxacin (0.25 mg/liter) than that for levofloxacin (MIC90, 2 mg/liter). Against ␤-hemolytic streptococci and viridans streptococci, of which 97% were susceptible to levofloxacin, the MIC90 of both AZD0914 and moxifloxacin was 0.25 mg/liter, regardless of specimen source or geographical region (data not shown). The activity of AZD0914 against Enterococcus faecalis, 16 (1.3%) isolates of which were vancomycin resistant, is shown in Table 3. The overall MIC90 of AZD0914 against E. faecalis was 1 mg/liter, with 98.8% of the isolates giving an AZD0914 MIC of ⱕ2 mg/liter. With only a 2-fold dilution difference observed in the

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TABLE 3 Activity of AZD0914 and levofloxacin tested against Enterococcus species Organism/phenotype (no. of isolates) E. faecalis All (1,241)

Vancomycin susceptible (1,107)

Vancomycin resistant (16)

Levofloxacin susceptible (874)

Levofloxacin resistant (362)

E. faecium All (946)

CLSI susceptibilitya Drug

MIC range

MIC50

MIC90

% Sus

% Int

% Res

AZD0914 Levofloxacin Ampicillin Erythromycin Linezolid Daptomycin Minocycline Tigecycline Quinupristin-dalfopristin Teicoplanin Vancomycin AZD0914 Levofloxacin Ampicillin Erythromycin Linezolid Daptomycin Minocycline Tigecycline Quinupristin-dalfopristin Teicoplanin Vancomycin AZD0914 Levofloxacin Ampicillin Erythromycin Linezolid Daptomycin Minocycline Tigecycline Quinupristin-dalfopristin Teicoplanin Vancomycin AZD0914 Levofloxacin Ampicillin Erythromycin Linezolid Daptomycin Minocycline Tigecycline Quinupristin-dalfopristin Teicoplanin Vancomycin AZD0914 Levofloxacin Ampicillin Erythromycin Linezolid Daptomycin Minocycline Tigecycline Quinupristin-dalfopristin Teicoplanin Vancomycin

ⱕ0.06 to 8 0.25 to ⬎8 ⱕ0.12 to ⬎16 ⱕ0.06 to ⬎8 0.12 to 4 ⱕ0.06 to 8 ⱕ0.06 to ⬎8 ⱕ0.015 to 2 0.25 to ⬎8 ⱕ0.12 to ⬎32 0.25 to ⬎32 ⱕ0.06 to 8 0.25 to ⬎8 ⱕ0.12 to ⬎16 ⱕ0.06 to ⬎8 0.25 to 4 ⱕ0.06 to 8 ⱕ0.06 to ⬎8 ⱕ0.015 to 1 0.25 to ⬎8 ⱕ0.12 to 16 0.25 to 4 0.25 to 0.5 ⬎8 to ⬎8 0.5 to 2 8 to ⬎8 1 to 2 1 to 4 0.12 to ⬎8 0.06 to 0.5 4 to ⬎8 0.25 to ⬎32 ⬎32 ⱕ0.06 to 8 0.25 to 2 ⱕ0.12 to 4 ⱕ0.06 to ⬎8 0.12 to 4 ⱕ0.06 to 8 ⱕ0.06 to ⬎8 ⱕ0.015 to 2 0.25 to ⬎8 ⱕ0.12 to 16 0.25 to 16 0.12 to 8 8 to ⬎8 0.25 to ⬎16 ⱕ0.06 to ⬎8 0.25 to 4 0.12 to 4 ⱕ0.06 to ⬎8 ⱕ0.015 to 1 1 to ⬎8 ⱕ0.12 to ⬎32 0.5 to ⬎32

0.5 1 1 ⬎8 1 2 ⬎8 0.12 8 0.5 1 0.5 1 1 ⬎8 1 2 ⬎8 0.12 8 0.25 1 0.25 ⬎8 1 ⬎8 1 2 ⬎8 0.12 ⬎8 32 ⬎32 0.5 1 1 2 1 2 ⬎8 0.12 0.25 0.25 1 0.5 ⬎8 1 ⬎8 1 2 ⬎8 0.12 8 0.5 1

1 ⬎8 2 ⬎8 2 4 ⬎8 0.25 ⬎8 0.5 8 1 ⬎8 2 ⬎8 2 4 ⬎8 0.25 ⬎8 0.5 2 0.5 ⬎8 2 ⬎8 2 4 ⬎8 0.25 ⬎8 ⬎32 ⬎32 1 2 2 ⬎8 2 4 ⬎8 0.25 ⬎8 0.5 4 1 ⬎8 2 ⬎8 2 4 ⬎8 0.25 ⬎8 1 8

NAb 70.4 99.9 12.2 99.6 99.7 26.9 94.2 1.6 98.9 89.2 NA 71.5 99.9 12.7 99.6 99.6 27.2 97.6 1.6 99.9 100 NA 0.0 100 0.0 100 100 12.5 93.8 0.0 18.8 0.0 NA 100 100 15.3 99.7 99.5 31.7 94.5 2.2 99.9 90.5 NA 0.0 99.7 4.4 99.5 100 14.6 93.4 0.3 96.4 86.2

NA 0.4 0.0 29.8 0.4 0.0 15.9 0.0 7.7 0.1 9.5 NA 0.4 0.0 29.1 0.5 0.0 16.5 0.0 7.9 0.1 0.0 NA 0.0 0.0 0.0 0.0 0.0 6.3 0.0 0.0 0.0 0.0 NA 0.0 0.0 39.0 0.3 0.0 17.5 0.0 9.7 0.1 9.5 NA 0.0 0.0 7.2 0.6 0.0 12.2 0.0 2.8 0.0 9.4

NA 29.2 0.1 58.0 0.0 0.3 57.2 5.8 90.7 1.1 1.3 NA 28.2 0.1 58.2 0.0 0.4 56.3 2.4 90.5 0.0 0.0 NA 100 0.0 100 0.0 0.0 81.3 6.3 100 81.3 100 NA 0.0 0.0 45.7 0.0 0.5 50.8 5.5 88.1 0.0 0.0 NA 100 0.3 88.4 0.0 0.0 73.2 6.6 97.0 3.6 4.4

AZD0914 Levofloxacin

ⱕ0.06 to ⬎128 0.25 to ⬎8

4 ⬎8

8 ⬎8

NA 12.7

NA 3.5

NA 83.8

(Continued on following page)

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TABLE 3 (Continued) Organism/phenotype (no. of isolates)

Vancomycin susceptible (657)

Vancomycin resistant (204)

Levofloxacin susceptible (120)

Levofloxacin resistant (793)

a b

CLSI susceptibilitya Drug

MIC range

MIC50

MIC90

% Sus

% Int

% Res

Ampicillin Erythromycin Linezolid Daptomycin Minocycline Tigecycline Quinupristin-dalfopristin Teicoplanin Vancomycin AZD0914 Levofloxacin Ampicillin Erythromycin Linezolid Daptomycin Minocycline Tigecycline Quinupristin-dalfopristin Teicoplanin Vancomycin AZD0914 Levofloxacin Ampicillin Erythromycin Linezolid Daptomycin Minocycline Tigecycline Quinupristin-dalfopristin Teicoplanin Vancomycin AZD0914 Levofloxacin Ampicillin Erythromycin Linezolid Daptomycin Minocycline Tigecycline Quinupristin-dalfopristin Teicoplanin Vancomycin AZD0914 Levofloxacin Ampicillin Erythromycin Linezolid Daptomycin Minocycline Tigecycline Quinupristin-dalfopristin Teicoplanin Vancomycin

ⱕ0.12 to ⬎16 0.12 to ⬎8 0.5 to 4 0.12 to ⬎8 ⱕ0.06 to ⬎8 ⱕ0.015 to ⬎4 1 to ⬎8 ⱕ0.12 to ⬎32 0.25 to ⬎32 ⱕ0.06 to 64 0.25 to ⬎8 ⱕ0.12 to ⬎16 0.12 to ⬎8 0.5 to 4 0.12 to ⬎8 ⱕ0.06 to ⬎8 ⱕ0.015 to ⬎4 0.12 to ⬎8 ⱕ0.12 to 16 0.25 to 4 0.5 to ⬎128 4 to ⬎8 8 to ⬎16 0.25 to ⬎8 0.5 to 4 0.25 to ⬎8 ⱕ0.06 to ⬎8 ⱕ0.015 to 2 0.25 to 8 0.25 to ⬎32 32 to ⬎32 ⱕ0.06 to 16 0.25 to 2 ⱕ0.12 to ⬎16 0.12 to ⬎8 0.5 to 2 0.12 to 8 ⱕ0.06 to ⬎8 0.03 to 1 0.25 to ⬎8 ⱕ0.12 to 16 0.25 to 16 0.25 to 64 8 to ⬎8 ⱕ0.12 to ⬎16 0.12 to ⬎8 0.5 to 4 0.12 to ⬎8 ⱕ0.06 to ⬎8 ⱕ0.015 to ⬎4 0.12 to ⬎8 ⱕ0.12 to ⬎32 0.25 to ⬎32

⬎16 ⬎8 1 4 4 0.12 1 1 1 4 ⬎8 ⬎16 ⬎8 1 4 2 0.12 1 1 1 8 ⬎8 ⬎16 ⬎8 1 4 8 0.12 1 ⬎32 ⬎32 1 2 2 4 2 4 0.25 0.12 2 0.5 1 4 ⬎8 ⬎16 ⬎8 1 4 4 0.12 1 1 2

⬎16 ⬎8 2 4 ⬎8 0.25 4 ⬎32 ⬎32 8 ⬎8 ⬎16 ⬎8 2 4 ⬎8 0.25 4 2 2 16 ⬎8 ⬎16 ⬎8 2 4 ⬎8 0.25 2 ⬎32 ⬎32 8 2 ⬎16 ⬎8 2 4 ⬎8 0.25 8 1 2 8 ⬎8 ⬎16 ⬎8 2 4 ⬎8 0.25 4 ⬎32 ⬎32

13.9 3.3 99.4 97.8 54.0 94.6 71.6 80.6 69.5 NA 17.5 18.7 4.6 99.4 97.6 56.0 96.5 69.3 99.9 100 NA 0.0 0.5 0.5 99.5 98.0 44.1 93.1 83.3 10.8 0.0 NA 100 81.7 7.5 100 96.7 60.8 95.0 30.0 99.2 95.8 NA 0.0 1.5 2.5 99.4 98.1 53.5 95.3 79.1 77.2 64.8

0.0 12.1 0.6 0.0 13.0 0.0 13.9 0.7 9.0 NA 4.3 0.0 16.1 0.6 0.0 9.9 0.0 15.4 0.2 0.0 NA 1.0 0.0 2.5 0.5 0.0 23.5 0.0 8.3 2.9 0.0 NA 0.0 0.0 54.2 0.0 0.0 2.5 0.0 42.5 0.8 4.2 NA 0.0 0.0 4.3 0.6 0.0 15.0 0.0 9.0 0.8 9.7

86.2 84.7 0.0 2.2 33.0 5.4 14.6 18.7 21.6 NA 78.2 81.3 79.3 0.0 2.4 34.1 3.5 15.4 0.0 0.0 NA 99.0 99.5 97.1 0.0 2.0 32.4 6.9 8.3 86.3 100 NA 0.0 18.3 38.3 0.0 3.3 36.7 5.0 27.5 0.0 0.0 NA 100 98.5 93.2 0.0 1.9 31.5 4.7 12.0 22.1 25.5

CLSI susceptibilities defined by CLSI document M100-S24 (18). Sus, susceptible; Int, intermediate; Res, resistant. NA, no breakpoint criteria available.

MIC50s and MIC90s between vancomycin-susceptible and -resistant isolates, vancomycin status did not affect the activity of AZD0914. The MIC90 for levofloxacin was ⬎8 mg/liter against E. faecalis, with 70.4% of the isolates being susceptible. AZD0914 was

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equally active against the levofloxacin-susceptible and levofloxacin-resistant E. faecalis isolates. Compared to E. faecalis, AZD0914 and comparator antibiotics demonstrated reduced activity against Enterococcus faecium (Table 3). The overall MIC90 of AZD0914

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AZD0914 In Vitro Activity

FIG 1 AZD0914 MIC distributions against methicillin-resistant S. aureus (MRSA) (n ⫽ 6,666), S. pneumoniae (n ⫽ 2,324), and E. faecalis (n ⫽ 1,241).

against E. faecium was 8 mg/liter. Similar activity was observed in the vancomycin-susceptible and -resistant populations, with AZD0914 MIC90s of 8 and 16 mg/liter, respectively. The MIC90 of levofloxacin was ⬎8 mg/liter for all E. faecium isolates tested, ir-

respective of vancomycin susceptibility, with only 17.5% of vancomycin-susceptible isolates and none of the vancomycin-resistant isolates being susceptible to levofloxacin. AZD0914 had similar activity against the levofloxacin-susceptible and levofloxa-

TABLE 4 Activity of AZD0914, levofloxacin, and moxifloxacin tested against Haemophilus spp. and Moraxella catarrhalis Organism/phenotype (no. of isolates)

CLSI susceptibilitya Drug

MIC range

MIC50

MIC90

% Sus

% Int

% Res

All H. influenzae spp. (352)

AZD0914 Levofloxacin Ampicillin Amoxicillin-clavulanic acid Piperacillin-tazobactam Tigecycline

0.03 to 2 ⱕ0.004 to ⬎4 ⱕ0.06 to ⬎8 ⱕ0.06 to 16 ⱕ0.015 to 0.5 ⱕ0.008 to 2

0.25 0.008 0.25 0.5 ⱕ0.015 0.12

0.5 0.015 ⬎8 2 0.06 0.5

NAb 99.2 78.7 99.4 100 82.7

NA 0.0 3.4 0.0 0.0 0.0

NA 0.9 17.9 0.6 0.0 17.3

␤-Lactamase-positive H. influenzae (60)

AZD0914 Levofloxacin Ampicillin Amoxicillin-clavulanic acid Piperacillin-tazobactam Tigecycline

0.12 to 2 ⱕ0.004 to 0.5 0.25 to ⬎8 0.25 to 16 ⱕ0.015 to 0.5 0.06 to 0.5

0.25 0.008 ⬎8 1 ⱕ0.015 0.12

0.5 0.015 ⬎8 4 0.06 0.5

NA 100 3.3 98.3 100 86.7

NA 0.0 0.0 0.0 0.0 0.0

NA 0.0 96.7 1.7 0.0 13.3

␤-Lactamase-negative H. influenzae (292)

AZD0914 Levofloxacin Ampicillin Amoxicillin-clavulanic acid Piperacillin-tazobactam Tigecycline

0.03 to 1 ⱕ0.004 to ⬎4 ⱕ0.06 to ⬎8 ⱕ0.06 to 8 ⱕ0.015 to 0.25 ⱕ0.008 to 2

0.25 0.008 0.25 0.5 ⱕ0.015 0.12

0.5 0.015 1 2 0.06 0.5

NA 99.0 94.2 99.7 100 81.9

NA 0.0 4.1 0.0 0.0 0.0

NA 1.0 1.7 0.3 0.0 18.2

H. parainfluenzae (70)

AZD0914 Levofloxacin Ampicillin Amoxicillin-clavulanic acid Piperacillin-tazobactam Tigecycline

ⱕ0.015 to 4 ⱕ0.004 to 2 0.12 to ⬎8 0.12 to 4 ⱕ0.015 to ⬎2 ⱕ0.008 to 1

1 0.015 0.25 0.5 0.12 0.25

2 0.5 4 1 0.5 0.5

NA 100 82.9 100 97.1 77.1

NA 0.0 4.3 0.0 0.0 0.0

NA 0.0 12.9 0.0 2.9 22.9

M. catarrhalis (145)

AZD0914 Levofloxacin Moxifloxacin Amoxicillin clavulanic Acid Ceftriaxone Erythromycin Clindamycin

0.015 to 0.5 ⱕ0.015 to ⬎2 ⱕ0.03 to ⬎2 ⱕ0.12 to 8 ⱕ0.5 to 16 ⱕ0.12 to ⬎4 0.06 to ⬎2

0.12 0.03 0.06 0.25 ⱕ0.5 ⱕ0.12 1

0.25 0.12 0.06 0.5 1 0.5 2

NA 99.3 NA 99.3 99.3 97.9 29.7

NA 0.0 NA 0.0 0.0 0.0 67.6

NA 0.7 NA 0.7 0.7 2.1 2.8

a b

CLSI susceptibilities defined by CLSI document M100-S24 (18). Sus, susceptible; Int, intermediate; Res, resistant. NA, no breakpoint criteria available.

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cin-resistant E. faecium isolates, with MIC90s of 8 mg/liter for both groups. As shown in Fig. 1, the AZD0914 MIC distributions against three key organism groups (MRSA, S. pneumoniae, and E. faecalis) were quite narrow, with the majority of MICs ranging from 0.12 to 0.25 mg/liter for both MRSA and S. pneumoniae, and from 0.5 to 1 mg/liter for E. faecalis. These results further reflect that regardless of geographic or specimen source, the activity of AZD0914 was consistent with narrow MIC distributions. The in vitro activities of AZD0914 and comparator antibiotics against fastidious Gram-negative respiratory pathogens are shown in Table 4. The MIC90 of AZD0914 against Haemophilus influenzae was 0.5 mg/liter (MIC range, 0.03 to 2 mg/liter), which included 60 (17.0%) ␤-lactamase-positive isolates. Most isolates (99.2%) were susceptible to levofloxacin, which had an MIC90 of 0.015 mg/liter. AZD0914 MIC90s were 0.5 mg/liter for isolates from all geographical regions. Among 70 Haemophilus parainfluenzae isolates, the MIC90 of AZD0914 was 2 mg/liter. All isolates were susceptible to levofloxacin (MIC90, 0.5 mg/liter). The overall MIC90 of AZD0914 against Moraxella catarrhalis was 0.25 mg/liter (Table 4). Only two isolates were identified with MICs of 0.5 mg/ liter, one ␤-lactamase-negative isolate and one ␤-lactamase-positive isolate. The MIC90s for levofloxacin and moxifloxacin were 0.12 and 0.06 mg/liter, respectively. DISCUSSION

This is the first comprehensive analysis of the in vitro activity of AZD0914 against a global collection of pathogens associated with numerous infection types. This novel agent exhibited excellent in vitro activity against all species tested, with the exception of E. faecium. Fluoroquinolones are among the most common antimicrobial agents prescribed for treating patient infections. The use of fluoroquinolones has prompted resistance to develop rather quickly among several highly important bacterial pathogens, both Grampositive (S. aureus) and Gram-negative (E. coli and N. gonorrhoeae [20–24]). Other species, such as Haemophilus spp. and ␤-hemolytic streptococci, have been less prone to becoming fluoroquinolone nonsusceptible but are emerging at high rates in some countries (25–31). Hampering the advancement of fluoroquinolones to include other more potent agents has been difficult, due to the safety profile observed for this class. Antimicrobial agents that represent a new class (spiropyrimidinetrione) and target a similar mechanism, namely, enzymes involved with DNA replication, may provide alternative treatment options for bacterial species that have become resistant to current fluoroquinolones. AZD0914 represents the first compound in a new class of gyrase/topoisomerase inhibitors with potent in vitro activity relative to levofloxacin and moxifloxacin against medically important Gram-positive and fastidious Gram-negative bacterial species, including fluoroquinolone-resistant clinical isolates. Cross-resistance between AZD0914 and other important Gram-positive class agents, including fluoroquinolones, ␤-lactams, macrolides, and glycopeptides, was not observed. The current indication being pursued for AZD0914 is uncomplicated gonococcal infections with additional in vitro activity demonstrated against other organisms responsible for sexually transmitted infections (STI), including C. trachomatis (13–16). The findings of this present study, based solely on in vitro activity, indicate that AZD0914 is a strong candidate for continued

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advancement as a therapeutic agent for infections caused by staphylococci, streptococci, enterococci, E. faecalis, M. catarrhalis, and H. influenzae. The spectrum of activity of AZD0914 suggests that it may have utility beyond STIs. AZD0914 has the potential to become an important novel antimicrobial agent within a new class that has broad coverage against important Gram-positive and fastidious Gram-negative pathogens isolated from multiple sources of infection. ACKNOWLEDGMENTS AstraZeneca Pharmaceuticals provided financial support for this investigation, and all authors provided analysis input and have read and approved the final manuscript. D.J.B., D.F.S., and M.D.H. are employees of International Health Management Associates, Inc. None of the IHMA authors have personal financial interests in the sponsor of this paper (AstraZeneca Pharmaceuticals). P.A.B. and B.L.M.D.J. are employees and stock holders of AstraZeneca Pharmaceuticals LP. We gratefully acknowledge the contributions of the clinical trial investigators, laboratory personnel, and all members of the global surveillance program that contributed isolates and information for this study.

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Topoisomerase IV Inhibitor, against Clinically Relevant Gram-Positive and Fastidious Gram-Negative Pathogens.

AZD0914, a new spiropyrimidinetrione bacterial DNA gyrase inhibitor with a novel mode of inhibition, has activity against bacterial species commonly c...
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