Sulfonamido-2-arylbenzoxazole GroEL/ES Inhibitors as Potent Antibacterials against Methicillin-Resistant Staphylococcus aureus (MRSA).
ABSTRACT: Extending from a study we recently published examining the antitrypanosomal effects of a series of GroEL/ES inhibitors based on a pseudosymmetrical bis-sulfonamido-2-phenylbenzoxazole scaffold, here, we report the antibiotic effects of asymmetric analogs of this scaffold against a panel of bacteria known as the ESKAPE pathogens ( Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species). While GroEL/ES inhibitors were largely ineffective against K. pneumoniae, A. baumannii, P. aeruginosa, and E. cloacae (Gram-negative bacteria), many analogs were potent inhibitors of E. faecium and S. aureus proliferation (Gram-positive bacteria, EC50 values of the most potent analogs were in the 1-2 ?M range). Furthermore, even though some compounds inhibit human HSP60/10 biochemical functions in vitro (IC50 values in the 1-10 ?M range), many of these exhibited moderate to low cytotoxicity to human liver and kidney cells (CC50 values > 20 ?M).
Project description:Multidrug-resistant (MDR) bacteria are a major threat to public health. Bacteriophage endolysins (lysins) are a promising alternative treatment to traditional antibiotics. However, the lysins currently under development are still underestimated. Herein, we cloned the lysin from the SAP-26 bacteriophage genome. The recombinant LysSAP26 protein inhibited the growth of carbapenem-resistant <i>Acinetobacter baumannii</i>, <i>Escherichia coli</i>, <i>Klebsiella pneumoniae</i>, and <i>Pseudomonas aeruginosa</i>, oxacillin-resistant <i>Staphylococcus aureus</i>, and vancomycin-resistant <i>Enterococcus faecium</i> with minimum inhibitory concentrations of 5~80 µg/mL. In animal experiments, mice infected with <i>A. baumannii</i> were protected by LysSAP26, with a 40% survival rate. Transmission electron microscopy analysis confirmed that LysSAP26 treatment resulted in the destruction of bacterial cell walls. LysSAP26 is a new endolysin that can be applied to treat MDR <i>A. baumannii</i>, <i>E. faecium</i>, <i>S. aureus</i>, <i>K. pneumoniae</i>, <i>P. aeruginosa</i>, and <i>E. coli</i> infections, targeting both Gram-positive and Gram-negative bacteria.
Project description:Background and objectives: For proper antimicrobial therapy, cumulative antibiograms should be representative of geographic region and be accurate. Clinical and Laboratory Standards Institute (CLSI) guidelines recommend that only the first isolates (FI) of a species per patient are used when reporting cumulative antibiograms. However, >50% of hospitals in the United States report antibiograms of all isolates. We compared antibiograms from the FI with those from total isolates (TI). Materials and Methods: Antimicrobial data of all isolates identified in the Microbiology unit of Ilsan Paik Hospital in 2019 were retrospectively acquired from the hospital information system. The susceptibility rates to antimicrobials of Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus faecium, and Enterococcus faecalis were analyzed by FI and TI, respectively. Isolate counts and susceptibility rates of each species for the reported antimicrobials were compared. Results: The numbers of isolates by FI/TI were as follows: 1824/2692 E. coli, 480/1611 A. baumannii, and 662/1306 K. pneumoniae, and 407/953 P. aeruginosa for gram-negative bacteria and 649/1364 S. aureus, 211/313 E. faecium, and 323/394 E. faecalis for gram-positive bacteria. All antimicrobial agents showed higher susceptibility rates when calculated as FI than as TI in gram-negative bacteria except colistin: 3.7% for E. coli, 14.5% for A. baumannii, 8.3% for K. pneumoniae, and 7.9% for P. aeruginosa. In S. aureus, 8/11 antimicrobial agents revealed higher susceptibility rates for FI than for TI. E. faecalis and E. faecium showed lower susceptibility rates for 7/10 antimicrobial agents for FI than for TI. The oxacillin susceptibility rates of S. aureus were 36.6%/30.2% with FI/TI and vancomycin susceptibility rates for E. faecium were 54.1% and 49.5%, respectively. Conclusions: When comparing cumulative antibiograms by FI with TI using real-world data, there is a large gap for critical species requiring hospital infection control. Although FI calculation is difficult, antibiograms must be calculated as FI for proper preemptive antimicrobial therapy because FI provides proper antimicrobial susceptibility data.
Project description:We recently reported the identification of a GroEL/ES inhibitor (1, N-(4-(benzo[ d]thiazol-2-ylthio)-3-chlorophenyl)-3,5-dibromo-2-hydroxybenzamide) that exhibited in vitro antibacterial effects against Staphylococcus aureus comparable to vancomycin, an antibiotic of last resort. To follow up, we have synthesized 43 compound 1 analogs to determine the most effective functional groups of the scaffold for inhibiting GroEL/ES and killing bacteria. Our results identified that the benzothiazole and hydroxyl groups are important for inhibiting GroEL/ES-mediated folding functions, with the hydroxyl essential for antibacterial effects. Several analogs exhibited >50-fold selectivity indices between antibacterial efficacy and cytotoxicity to human liver and kidney cells in cell culture. We found that MRSA was not able to easily generate acute resistance to lead inhibitors in a gain-of-resistance assay and that lead inhibitors were able to permeate through established S. aureus biofilms and maintain their bactericidal effects.
Project description:Acinetobacter baumannii is a Gram-negative bacterium capable of causing hospital-acquired infections that has been grouped with Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species as ESKAPE pathogens because of their extensive drug resistance phenotypes and increasing risk to human health. Twenty-four multidrug-resistant A. baumannii strains isolated from wounded military personnel were sequenced and annotated.
Project description:ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) are among the most common opportunistic pathogens in nosocomial infections. ESKAPE pathogens distinguish themselves from normal ones by developing a high level of antibiotic resistance that involves multiple mechanisms. Contemporary therapeutic strategies which are potential options in combating ESKAPE bacteria need further investigation. Herein, a broad overview of the antimicrobial research on ESKAPE pathogens over the past five years is provided with prospective clinical applications.
Project description:Pseudomonas aeruginosa, a Gram-negative bacterium that causes severe hospital-acquired infections, is grouped as an ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogen because of its extensive drug resistance phenotypes and effects on human health worldwide. Five multidrug resistant P. aeruginosa strains isolated from wounded military personnel were sequenced and annotated in this work.
Project description:Antimicrobial agents are used in both veterinary and human medicine. The intensive use of antimicrobials in animals may promote the fixation of antimicrobial resistance genes in bacteria, which may be zoonotic or capable to transfer these genes to human-adapted pathogens or to human gut microbiota via direct contact, food or the environment. This review summarizes the current knowledge of the use of antimicrobial agents in animal health and explores the role of bacteria from animals as a pool of antimicrobial resistance genes for human bacteria. This review focused in relevant examples within the ESC(K)APE (Enterococcus faecium, Staphylococcus aureus, Clostridium difficile (Klebsiella pneumoniae), Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacteriaceae) group of bacterial pathogens that are the leading cause of nosocomial infections throughout the world.
Project description:Klebsiella pneumoniae, an ESKAPE group (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogen, has acquired multiple antibiotic resistance genes and is becoming a serious public health threat. Here, we report the genome sequences of two representative strains of K. pneumoniae from the emerging K. pneumoniae carbapenemase (KPC) outbreak in northeast Ohio belonging to sequence type 258 (ST258) (isolates Kb140 and Kb677, which were isolated from blood and urine, respectively). Both isolates harbor a blaKPC gene, and strain Kb140 carries blaKPC-2, while Kb677 carries blaKPC-3.
Project description:Addressing the growing problem of antibiotic resistance requires the development of new drugs with novel antibacterial targets. FtsZ has been identified as an appealing new target for antibacterial agents. Here, we describe the structure-guided design of a new fluorescent probe (BOFP) in which a BODIPY fluorophore has been conjugated to an oxazole-benzamide FtsZ inhibitor. Crystallographic studies have enabled us to identify the optimal position for tethering the fluorophore that facilitates the high-affinity FtsZ binding of BOFP. Fluorescence anisotropy studies demonstrate that BOFP binds the FtsZ proteins from the Gram-positive pathogens Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium, Streptococcus pyogenes, Streptococcus agalactiae, and Streptococcus pneumoniae with Kd values of 0.6-4.6?µM. Significantly, BOFP binds the FtsZ proteins from the Gram-negative pathogens Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii with an even higher affinity (Kd?=?0.2-0.8?µM). Fluorescence microscopy studies reveal that BOFP can effectively label FtsZ in all the above Gram-positive and Gram-negative pathogens. In addition, BOFP is effective at monitoring the impact of non-fluorescent inhibitors on FtsZ localization in these target pathogens. Viewed as a whole, our results highlight the utility of BOFP as a powerful tool for identifying new broad-spectrum FtsZ inhibitors and understanding their mechanisms of action.
Project description:Antimicrobial peptides have been identified as one of the alternatives to the extensive use of common antibiotics as they show a broad spectrum of activity against human pathogens. Among these is Chionodracine (Cnd), a host-defense peptide isolated from the Antarctic icefish Chionodraco hamatus, which belongs to the family of Piscidins. Previously, we demonstrated that Cnd and its analogs display high antimicrobial activity against ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter species). Herein, we investigate the interactions with lipid membranes of Cnd and two analogs, Cnd-m3 and Cnd-m3a, showing enhanced potency. Using a combination of Circular Dichroism, fluorescence spectroscopy, and all-atom Molecular Dynamics (MD) simulations, we determined the structural basis for the different activity among these peptides. We show that all peptides are predominantly unstructured in water and fold, preferentially as ?-helices, in the presence of lipid vesicles of various compositions. Through a series of MD simulations of 400 ns time scale, we show the effect of mutations on the structure and lipid interactions of Cnd and its analogs. By explaining the structural basis for the activity of these analogs, our findings provide structural templates to design minimalistic peptides for therapeutics.