Small Molecule Benzothiophene with Efficacy in a Mouse Model of Drug-Resistant Infection.

Hospital-acquired infections, caused by ESKAPE bacteria, are a challenging global public health concern, in part due to the emergence of drug-resistant strains. While profiling a diverse set of compounds for activity this class of bacteria, we noted that the benzothiophene JSF-2827 exhibited promising antibacterial activity against . A hit evolution campaign ensued, involving the design, synthesis, and biological assay of analogues designed to address early issues such as a short mouse liver microsome half-life and a modest mouse pharmacokinetic profile.

Novel Pyrimidines as Antitubercular Agents.

infection is responsible for a global pandemic. New drugs are needed that do not show cross-resistance with the existing front-line therapeutics. A triazine antitubercular hit led to the design of a related pyrimidine family.

In vitro activity of tigecycline against patient isolates collected during phase 3 clinical trials for diabetic foot infections.

The in vitro activity of tigecycline and comparative antimicrobial agents was evaluated against 1828 primary baseline pathogens isolated from 844 patients enrolled in the phase 3 clinical trials investigating the efficacy of tigecycline in diabetic foot infection (DFI). The trials were global, enrolling patients in 30 countries. Tigecycline was active against the most prevalent pathogens in DFI, including Gram-positive and Gram-negative isolates of both aerobic and anaerobic bacteria with 95% of MICs < or =2 microg/mL for the entire collection.

Identification of CTX-M beta-lactamases in Escherichia coli from hospitalized patients and residents of long-term care facilities.

Bacteria harboring CTX-M extended-spectrum beta-lactamases (ESBLs) have been identified worldwide, with most reports coming from regions outside North America. We have identified CTX-M enzymes in 31% of ESBL-positive Escherichia coli isolates from our hospital and more than half (53%) of the isolates from associated long-term care facilities. Approximately 3/4 of all CTX-M-bearing isolates were from urine specimens, with a predominance of CTX-M-15.

In vitro activity of tigecycline against patient isolates collected during phase 3 clinical trials for hospital acquired pneumonia.

The in vitro activity of tigecycline was evaluated against 819 baseline pathogens isolated from 383 patients enrolled in the phase 3 clinical trial investigating the efficacy of tigecycline in hospital acquired pneumonia (HAP). The trials were global, enrolling patients in 27 countries. Tigecycline was active against the most prevalent pathogens in HAP, including gram-positive and gram-negative strains (90% of MICs ≤2 µg/mL for the entire collection).

Pyrosequencing using the single-nucleotide polymorphism protocol for rapid determination of TEM- and SHV-type extended-spectrum beta-lactamases in clinical isolates and identification of the novel beta-lactamase genes blaSHV-48, blaSHV-105, and blaTEM-155.

TEM- and SHV-type extended-spectrum beta-lactamases (ESBLs) are the most common ESBLs found in the United States and are prevalent throughout the world. Amino acid substitutions at a number of positions in TEM-1 lead to the ESBL phenotype, although substitutions at residues 104 (E to K), 164 (R to S or H), 238 (G to S), and 240 (E to K) appear to be particularly important in modifying the spectrum of activity of the enzyme. The SHV-1-derived ESBLs are a less diverse collection of enzymes; however, the majority of amino acid substitutions resulting in an ESBL mirror those seen in the TEM-1-derived enzymes.

Characterization and sequence analysis of extended-spectrum-{beta}-lactamase-encoding genes from Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis isolates collected during tigecycline phase 3 clinical trials.

In concert with the development of novel beta-lactams and broad-spectrum cephalosporins, bacterially encoded beta-lactamases have evolved to accommodate the new agents. This study was designed to identify, at the sequence level, the genes responsible for the extended-spectrum-beta-lactamase (ESBL) phenotypes of Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis isolates collected during the global tigecycline phase 3 clinical trials. PCR assays were developed to identify and clone the bla(TEM), bla(SHV), bla(OXA), and bla(CTX) genes from clinical strains.

Carbapenem-resistant Escherichia coli harboring Klebsiella pneumoniae carbapenemase beta-lactamases associated with long-term care facilities.

Nine carbapenem-resistant Escherichia coli isolates harboring Klebsiella pneumoniae carbapenemase (KPC)-2 or KPC-3 enzymes were identified in patients residing in 7 distinct long-term care facilities. Cefotaxime-hydrolyzing (CTX-M)-type beta-lactamases were also documented in 3 isolates. The identification of these enzymes in patients staying in long-term care facilities should be of great concern to all components of health care systems.

Occurrence of tetracycline resistance genes among Escherichia coli isolates from the phase 3 clinical trials for tigecycline.

Tigecycline, a member of the glycylcycline class of antibiotics, was designed to maintain the antibacterial spectrum of the tetracyclines while overcoming the classic mechanisms of tetracycline resistance. The current study was designed to monitor the prevalence of the tet(A), tet(B), tet(C), tet(D), tet(E), and tet(M) resistance determinants in Escherichia coli isolates collected during the worldwide tigecycline phase 3 clinical trials. A subset of strains were also screened for the tet(G), tet(K), tet(L), and tet(Y) genes.

Identification and sequence of a tet(M) tetracycline resistance determinant homologue in clinical isolates of Escherichia coli.

The presence of the tetracycline resistance determinant tet(M) in human clinical isolates of Escherichia coli is described for the first time in this report. The homologue was >99% identical to the tet(M) genes reported to occur in Lactobacillus plantarum, Neisseria meningitidis, and Streptococcus agalactiae, and 3% of the residues in its deduced amino acid sequence diverge from tet(M) of Staphylococcus aureus. Sequence analysis of the regions immediately flanking the gene revealed that sequences upstream of tet(M) in E.

Diagnostic PCR analysis of the occurrence of methicillin and tetracycline resistance genes among Staphylococcus aureus isolates from phase 3 clinical trials of tigecycline for complicated skin and skin structure infections.

Diagnostic PCR assays were developed to track common genetic determinants of oxacillin resistance as well as resistance to classical tetracyclines in Staphylococcus aureus isolates from the recently completed worldwide phase 3 clinical trials of tigecycline. A total of 503 unique S. aureus strains isolated from complicated skin and skin structure infections were analyzed.

Use of structure-based drug design approaches to obtain novel anthranilic acid acyl carrier protein synthase inhibitors.

Acyl carrier protein synthase (AcpS) catalyzes the transfer of the 4'-phosphopantetheinyl group from the coenzyme A to a serine residue in acyl carrier protein (ACP), thereby activating ACP, an important step in cell wall biosynthesis. The structure-based design of novel anthranilic acid inhibitors of AcpS, a potential antibacterial target, is presented. An initial high-throughput screening lead and numerous analogues were modeled into the available AcpS X-ray structure, opportunities for synthetic modification were identified, and an iterative process of synthetic modification, X-ray complex structure determination with AcpS, biological testing, and further modeling ultimately led to potent inhibitors of the enzyme.

Combinatorial synthesis of substituted 3-(2-indolyl)piperidines and 2-phenyl indoles as inhibitors of ZipA-FtsZ interaction.

The ZipA-FtsZ protein-protein interaction is a potential target for antibacterial therapy. The design and parallel synthesis of a combinatorial library of small molecules, which target the FtsZ binding area on ZipA are described. Compounds were demonstrated to bind to the FtsZ binding domain of ZipA by HSQC NMR and to inhibit cell division in a cell elongation assay.

Design and synthesis of indolo[2,3-a]quinolizin-7-one inhibitors of the ZipA-FtsZ interaction.

The binding of FtsZ to ZipA is a potential target for antibacterial therapy. Based on a small molecule inhibitor of the ZipA-FtsZ interaction, a parallel synthesis of small molecules was initiated which targeted a key region of ZipA involved in FtsZ binding. The X-ray crystal structure of one of these molecules complexed with ZipA was solved.