Discovery of MC-02,331, a New Cephalosporin Exhibiting Potent Activity Against Methicillin-resistant Staphylococcus aureus.

Hecker, Scott J.; Cho, In-Seop; Glinka, Tomasz; Zhang, Zhijia J.; Price, Matt D.; Lee, Ving J.; Christensen, B. G.; Boggs, Amy F; Chamberland, Suzanne; Malouin, François; Parr, Thomas; Annamalai, Thamil; Blais, Johanne; Bond, Emmett L.; Case, Laura C.; Chan, Christine; Crase, J. L.; Frith, Ria; Griffith, David C.; Harford, Laurie; Liu, Naian; Ludwikow, M.; Mathias, Kristina; Rea, David; Williams, Robert M.

doi:10.7164/antibiotics.51.722

Cited by 18 publications

(5 citation statements)

References 10 publications

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“…Methicillin exhibited an even poorer binding affinity to PBP2a* than did benzylpenicillin, as indicated by a 36-fold decrease in the k 2 / K d value. This is consistent with the observation that the MIC value of methicillin against MRSA was about 32-fold higher than that of benzylpenicillin ( , ). If the individual parameters are compared for the two compounds, the decrease in the binding efficiency for methicillin is mostly due to the decrease in k 2 (∼22-fold), implying that the step of the ester bond formation plays a more important role than the first step of molecular recognition.…”

Section: Discussionsupporting

confidence: 92%

“…Compound 1 is a cephalosporin described early by R. Woodward and co-workers (31). It was recently demonstrated that the β-lactam (named MC02,002) and its derivatives exhibited high activities in binding membrane-anchored PBP2a and against gram positive bacteria including MRSA (6). Three or four new β-lactams with PBP2a-binding affinity comparable to that of Compound 1 have also been reported by scientists of several pharmaceutical companies (6).…”

Section: Resultsmentioning

confidence: 99%

“…The latter conclusion is supported by several lines of genetic and biochemical evidence (3)(4)(5). PBP2a has been utilized by a number of pharmaceutical companies as a target to discover new β-lactam antibiotics with enhanced affinity to the protein and thus with potent activity against MRSA, and several such β-lactams have been reported (6). MecA, the gene coding for PBP2a, has been cloned and sequenced (7)(8)(9).…”

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confidence: 88%

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Penicillin-Binding Protein 2a from Methicillin-Resistant Staphylococcus aureus: Kinetic Characterization of Its Interactions with β-Lactams Using Electrospray Mass Spectrometry

Sun

Bauer

et al. 1999

Biochemistry

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Penicillin-binding protein 2a (PBP2a) is the primary beta-lactam resistance determinant of methicillin-resistant Staphylococcus aureus (MRSA). MecA, the gene coding for PBP2a, was cloned with the membrane-anchoring region at the N-terminus deleted. The truncated protein (PBP2a) was overexpressed in Escherichia coli mostly in the soluble form accounting for approximately 25% of soluble cell protein and was purified to homogeneity. The purified protein was shown to covalently bind beta-lactams in an 1:1 ratio as determined by electrospray mass spectrometry. A novel method based on HPLC-elctrospray mass spectrometry has been developed to quantitatively determine the formation of the covalent adducts or acyl-PBP2a complexes. By using this method, combined with kinetic techniques including quench flow, we have extensively characterized the interactions between PBP2a and three beta-lactams and determined related kinetic parameters for the first time. The apparent first-order rate constants (ka) of PBP2a acylation by benzylpenicillin showed a hyperbolic dependence on the concentration of benzylpenicillin. This is consistent with the mechanism that the binding of the penicillin to PBP2a consists of reversible formation of a Michaelis complex followed by formation of the penicilloyl-PBP2a adduct, and allowed the determination of the individual kinetic parameters for these two steps, the dissociation constant Kd of 13.3 mM and the first-order rate constant k2 of 0.22 s-1. From these values, the second-order rate constant k2/Kd, the value reflecting the overall binding efficiency of a beta-lactam, of 16.5 M-1 s-1 was obtained. The fairly high Kd value indicates that benzylpenicillin fits rather poorly into the protein active site. Similar studies on the interaction between PBP2a and methicillin revealed k2 of 0.0083 s-1 and Kd of 16.9 mM, resulting in an even smaller k2/Kd value of 0.49 M-1 s-1. The rate constants k3 for deacylation of the acyl-PBP2a complexes, the third step in the interactions, were measured to be <1.5 x 10(-)5 s-1. These results indicate that the resistance of PBP2a to penicillin inactivation is mainly due to the extremely low penicillin acylating rate in addition to the low association affinity, but not to a fast rate of deacylation. Acylation of PBP2a by a high-affinity cephalosporin, Compound 1, also followed a saturation curve of ka versus the compound concentration, from which k2 = 0.39 s-1, Kd = 0.22 mM, and k2/Kd = 1750 M-1 s-1 were obtained. The 100-fold increase in the k2/Kd value as compared with that of benzylpenicillin is mostly attributable to the decreased (60-fold) Kd, indicating that the cephalosporin fits much better to the binding pocket of the protein.

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Section: Discussionsupporting

confidence: 92%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 88%

See 1 more Smart Citation

Penicillin-Binding Protein 2a from Methicillin-Resistant Staphylococcus aureus: Kinetic Characterization of Its Interactions with β-Lactams Using Electrospray Mass Spectrometry

Sun

Bauer

et al. 1999

Biochemistry

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“…This PBP is causally connected with methicillin resistance, as it functions as a transpeptidase and is not efficiently inhibited by commercially available ␤-lactams, in contrast to the other transpeptidases in staphylococci, PBP 1, PBP 2, and PBP 3. However, the poor affinity of PBP 2Ј for ␤-lactam antibiotics does not seem to be inherent in the ␤-lactam structure since new carbapenems and cephalosporins that are good inhibitors of PBP 2Ј have recently been described (1,6,11,12,14,20).Ro 63-9141, the active principle of the water-soluble prodrug Ro 65-5788, is a novel parenteral cephalosporin with broad-spectrum activity against gram-positive and gram-negative pathogens. It differs from older, broad-spectrum cephalosporins in that it has antibacterial activity against MRS isolates.…”

mentioning

confidence: 99%

In Vitro and In Vivo Properties of Ro 63-9141, a Novel Broad-Spectrum Cephalosporin with Activity against Methicillin-Resistant Staphylococci

Hebeisen

Heinze‐Krauss

Angehrn

et al. 2001

Antimicrob Agents Chemother

205

236

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Ro 63-9141 is a new member of the pyrrolidinone-3-ylidenemethyl cephem series of cephalosporins. Its antibacterial spectrum was evaluated against significant gram-positive and gram-negative pathogens in comparison with those of reference drugs, including cefotaxime, cefepime, meropenem, and ciprofloxacin. Ro 63-9141 showed high antibacterial in vitro activity against gram-positive bacteria except ampicillin-resistant enterococci, particularly vancomycin-resistant strains of Enterococcus faecium. Its MIC at which 90% of the isolates tested were inhibited (MIC 90 ) for methicillin-resistant Staphylococcus aureus (MRSA) was 4 g/ml. Ro 63-9141 was bactericidal against MRSA. Development of resistance to the new compound in MRSA was not observed. Ro 63-9141 was more potent than cefotaxime against penicillin-resistant Streptococcus pneumoniae (MIC 90 ‫؍‬ 2 g/ml). It was active against ceftazidime-susceptible strains of Pseudomonas aeruginosa and against Enterobacteriaceae except Proteus vulgaris and some isolates producing extended-spectrum ␤-lactamases. The basis for the antibacterial spectrum of Ro 63-9141 lies in its affinity to essential penicillin-binding proteins, including PBP 2 of MRSA, and its stability towards ␤-lactamases. The in vivo findings were in accordance with the in vitro susceptibilities of the pathogens. These data suggest the potential utility of Ro 63-9141 for the therapy of infections caused by susceptible pathogens, including MRSA. Since insufficient solubility of Ro 63-9141 itself precludes parenteral administration in humans, a water-soluble prodrug, Ro 65-5788, is considered for development.Methicillin-resistant staphylococci (MRS) have become a serious problem in many parts of the world. Although the incidence of strains of methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant Staphylococcus epidermidis (MRSE), and other MRS varies from country to country and from hospital to hospital (3, 5), it has been steadily increasing worldwide in the last decade (10,18,19). MRS are resistant not only to the available ␤-lactam antibiotics, but also, in most instances, to structurally unrelated classes of antibacterials (for mainly unknown reasons) and thus represent a prime target in the current search for new antimicrobials.MRS are characterized by the expression of a special penicillin-binding protein (PBP), PBP 2Ј, that is not present in methicillin-susceptible staphylococci. This PBP is causally connected with methicillin resistance, as it functions as a transpeptidase and is not efficiently inhibited by commercially available ␤-lactams, in contrast to the other transpeptidases in staphylococci, PBP 1, PBP 2, and PBP 3. However, the poor affinity of PBP 2Ј for ␤-lactam antibiotics does not seem to be inherent in the ␤-lactam structure since new carbapenems and cephalosporins that are good inhibitors of PBP 2Ј have recently been described (1,6,11,12,14,20).Ro 63-9141, the active principle of the water-soluble prodrug Ro 65-5788, is a novel parenteral cephalosporin with broad-spe...

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“…These include the use of antibiotic combinations (8,36,49), the development of new members of existing antibiotic classes (5,15,16,24,27), and the introduction of novel agents (28,44). Novel classes will be particularly advantageous since such agents, with unique modes of action, are likely to circumvent existing resistance mechanisms (3).…”

mentioning

confidence: 99%

Biological Properties of Novel Antistaphylococcal Quinoline-Indole Agents

Oliva

Miller

Caggiano

et al. 2003

Antimicrob Agents Chemother

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The antibacterial properties of novel quinoline-indole (QI) agents were examined. QI agents demonstrated potent bactericidal activities against Staphylococcus aureus, killing by lytic and nonlytic mechanisms. S. aureus mutants resistant to a lytic QI agent (SEP 155342) and a nonlytic QI agent (SEP 118843) arose at frequencies of 1.4 ؋ 10 ؊9 and 1.2 ؋ 10 ؊8 , respectively, by selection at four times the MICs. Mutants resistant to QI agent SEP 155342 were unstable, but mutants resistant to QI agent SEP 118843 displayed stable resistance. Mutants resistant to QI agent SEP 118843 were not cross resistant to other inhibitors, including QI agent SEP 155342. Addition of QI agents SEP 118843 and SEP 155342 at four times the MIC caused nonspecific inhibition of several macromolecular biosynthetic pathways in S. aureus. Within 10 min, QI agents SEP 118843 and SEP 155342 both interfered with bacterial membrane integrity, as measured by uptake of propidium iodide. Agents from the two classes of the QI agents probably kill staphylococci by separate mechanisms which, nevertheless, both involve interference with cytoplasmic membrane function. Precise structure-activity relationships for the division of QI agents into two classes could not be determined. However, lytic activity was often associated with substitution of a basic amine at position 4 of the quinoline nucleus, whereas compounds with nonlytic activity usually contained an aromatic ring with or without a methoxy substituent at position 4. Nonlytic QI agents such as SEP 118843 may possess selective activity against the prokaryotic membrane since this compound failed to lyse mouse erythrocytes when it was added at a concentration equivalent to four times the MIC for S. aureus.Resistance to antibiotics is a major problem in the management of infections caused by gram-positive bacteria (9, 21, 31). The situation is particularly critical for treatment of infections caused by Staphylococcus aureus, in which methicillin-resistant (MRSA) and glycopeptide intermediate-resistant (GISA) strains have emerged; these strains are also frequently resistant to multiple classes of antibiotics (27,45). The recent report of an MRSA isolate resistant to the new oxazolidinone antimicrobial linezolid (46) is a further disturbing trend in the evolution of antimicrobial resistance in staphylococci. New approaches are therefore required to combat staphylococcal infections (24).Several new strategies to control staphylococcal infections have been considered in recent years. These include the use of antibiotic combinations (8,36,49), the development of new members of existing antibiotic classes (5,15,16,24,27), and the introduction of novel agents (28,44). Novel classes will be particularly advantageous since such agents, with unique modes of action, are likely to circumvent existing resistance mechanisms (3). Recently, a novel structural class of antibacterials, the quinoline-indole (QI) agents, was discovered in a library of compounds generated by combinatorial methods (19). None of the compou...

show abstract

Discovery of MC-02,331, a New Cephalosporin Exhibiting Potent Activity Against Methicillin-resistant Staphylococcus aureus.

Cited by 18 publications

References 10 publications

Penicillin-Binding Protein 2a from Methicillin-Resistant Staphylococcus aureus: Kinetic Characterization of Its Interactions with β-Lactams Using Electrospray Mass Spectrometry

Penicillin-Binding Protein 2a from Methicillin-Resistant Staphylococcus aureus: Kinetic Characterization of Its Interactions with β-Lactams Using Electrospray Mass Spectrometry

In Vitro and In Vivo Properties of Ro 63-9141, a Novel Broad-Spectrum Cephalosporin with Activity against Methicillin-Resistant Staphylococci

Biological Properties of Novel Antistaphylococcal Quinoline-Indole Agents

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