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Bhowmick J, Nag M, Ghosh P, Rajmani RS, Chatterjee R, Karmakar K, Chandra K, Chatterjee J, Chakravortty D, Varadarajan R. A CcdB toxin-derived peptide acts as a broad-spectrum antibacterial therapeutic in infected mice. EMBO Rep 2023; 24:e55338. [PMID: 37166011 PMCID: PMC10328072 DOI: 10.15252/embr.202255338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 04/16/2023] [Accepted: 04/21/2023] [Indexed: 05/12/2023] Open
Abstract
The bacterial toxin CcdB (Controller of Cell death or division B) targets DNA Gyrase, an essential bacterial topoisomerase, which is also the molecular target for fluoroquinolones. Here, we present a short cell-penetrating 24-mer peptide, CP1-WT, derived from the Gyrase-binding region of CcdB and examine its effect on growth of Escherichia coli, Salmonella Typhimurium, Staphylococcus aureus and a carbapenem- and tigecycline-resistant strain of Acinetobacter baumannii in both axenic cultures and mouse models of infection. The CP1-WT peptide shows significant improvement over ciprofloxacin in terms of its in vivo therapeutic efficacy in treating established infections of S. Typhimurium, S. aureus and A. baumannii. The molecular mechanism likely involves inhibition of Gyrase or Topoisomerase IV, depending on the strain used. The study validates the CcdB binding site on bacterial DNA Gyrase as a viable and alternative target to the fluoroquinolone binding site.
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Grants
- Department of Biotechnology, Ministry of Science and Technology, India - Indian Institute of Science (DBT-IISc) partnership program
- BT/COE/34/SP15219/2015 Department of Biotechnology, Ministry of Science and Technology, India
- DT.20/11/2015 Department of Biotechnology, Ministry of Science and Technology, India
- Department of Science and Technology, Ministry of Science and Technology, India (DST FIST)
- Ministry of Education, India (MHRD)
- University Grants Commission, Ministry of Education, India (UGC Centre for Advanced Studies)
- Department of Biotechnology, Ministry of Science and Technology, India
- Ministry of Education, India (MHRD)
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Affiliation(s)
- Jayantika Bhowmick
- Molecular Biophysics Unit (MBU)Indian Institute of ScienceBangaloreIndia
| | - Manish Nag
- Molecular Biophysics Unit (MBU)Indian Institute of ScienceBangaloreIndia
| | - Pritha Ghosh
- Molecular Biophysics Unit (MBU)Indian Institute of ScienceBangaloreIndia
| | - Raju S Rajmani
- Molecular Biophysics Unit (MBU)Indian Institute of ScienceBangaloreIndia
| | - Ritika Chatterjee
- Department of Microbiology and Cell BiologyIndian Institute of ScienceBangaloreIndia
| | - Kapudeep Karmakar
- Department of Microbiology and Cell BiologyIndian Institute of ScienceBangaloreIndia
| | - Kasturi Chandra
- Department of Microbiology and Cell BiologyIndian Institute of ScienceBangaloreIndia
| | - Jayanta Chatterjee
- Molecular Biophysics Unit (MBU)Indian Institute of ScienceBangaloreIndia
| | - Dipshikha Chakravortty
- Department of Microbiology and Cell BiologyIndian Institute of ScienceBangaloreIndia
- School of BiologyIndian Institute of Science Education and Research Thiruvananthapuram (IISER TVM)ThiruvananthapuramIndia
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Khanafer N, Daneman N, Greene T, Simor A, Vanhems P, Samore M, Brown KA. Susceptibilities of clinical Clostridium difficile isolates to antimicrobials: a systematic review and meta-analysis of studies since 1970. Clin Microbiol Infect 2017; 24:110-117. [PMID: 28750918 DOI: 10.1016/j.cmi.2017.07.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 07/10/2017] [Accepted: 07/13/2017] [Indexed: 12/29/2022]
Abstract
OBJECTIVES Although exposure to antibiotics can cause Clostridium difficile infection, certain antibiotics are used to treat C. difficile. Measurements of antimicrobial C. difficile activity could help to identify antibiotic risk and emergent resistance. Here, we describe publication patterns relating to C. difficile susceptibilities and estimate minimum inhibitory concentrations (MIC) for antibiotic classes in the published literature between January 1970 and June 2014. METHODS We queried PUBMED and EMBASE for studies reporting antibiotic C. difficile MIC in English or French. We used mixed-effects models to obtain pooled estimates of antibiotic class median MIC (MIC50), 90th percentile of MIC (MIC90), and MIC90:MIC50 ratio. RESULTS Our search identified 182 articles that met our inclusion criteria, of which 27 were retained for meta-analysis. Aminoglycosides (MIC50 120 mg/L, 95% CI 62-250), 3rd (MIC50 75 mg/L, 95% CI 39-130) and 2nd generation cephalosporins (MIC50 64 mg/L, 95% CI 27-140) had the least C. difficile activity. Rifamycins (MIC50 0.034 mg/L, 95% CI 0.012-0.099) and tetracyclines (MIC50 0.29 mg/L, 95% CI 0.054-1.7) had the highest level of activity. The activity of 3rd generation cephalosporins was more than three times lower than that of 1st generation agents (MIC50 19 mg/L, 95% CI 7.0-54). Time-trends in MIC50 were increasing for carbapenems (70% increase per 10 years) while decreasing for tetracyclines (51% decrease per 10 years). CONCLUSIONS We found a 3500-fold variation in antibiotic C. difficile MIC50, with aminoglycosides as the least active agents and rifamycins as the most active. Further research is needed to determine how in vitro measures can help assess patient C. difficile risk and guide antimicrobial stewardship.
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Affiliation(s)
- N Khanafer
- Service d'Hygiène, Épidémiologie et Prévention, Hôpital Edouard Herriot, Hospices civils de Lyon, Lyon, France; Centre International de Recherche en Infectiologie, Institut national de la santé et de la recherche médicale U1111, Centre National de la Recherche Scientifique UMR5308, Ecole Normale Supérieure de Lyon, Université Claude Bernard 1, Lyon, France.
| | - N Daneman
- Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada
| | - T Greene
- Division of Epidemiology, University of Utah, UT, USA
| | - A Simor
- Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada
| | - P Vanhems
- Service d'Hygiène, Épidémiologie et Prévention, Hôpital Edouard Herriot, Hospices civils de Lyon, Lyon, France; Centre International de Recherche en Infectiologie, Institut national de la santé et de la recherche médicale U1111, Centre National de la Recherche Scientifique UMR5308, Ecole Normale Supérieure de Lyon, Université Claude Bernard 1, Lyon, France
| | - M Samore
- Division of Epidemiology, University of Utah, UT, USA; Salt Lake City Veterans Affairs Health Care System, Salt Lake City, UT, USA
| | - K A Brown
- Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada; Division of Epidemiology, University of Utah, UT, USA; Salt Lake City Veterans Affairs Health Care System, Salt Lake City, UT, USA; Public Health Ontario, Ontario, Canada.
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Novel Bacterial Topoisomerase Inhibitors with Potent Broad-Spectrum Activity against Drug-Resistant Bacteria. Antimicrob Agents Chemother 2017; 61:AAC.02100-16. [PMID: 28223393 PMCID: PMC5404544 DOI: 10.1128/aac.02100-16] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 01/27/2017] [Indexed: 12/30/2022] Open
Abstract
The novel bacterial topoisomerase inhibitor class is an investigational type of antibacterial inhibitor of DNA gyrase and topoisomerase IV that does not have cross-resistance with the quinolones. Here, we report the evaluation of the in vitro properties of a new series of this type of small molecule. Exemplar compounds selectively and potently inhibited the catalytic activities of Escherichia coli DNA gyrase and topoisomerase IV but did not block the DNA breakage-reunion step. Compounds showed broad-spectrum inhibitory activity against a wide range of Gram-positive and Gram-negative pathogens, including biodefence microorganisms and Mycobacterium tuberculosis No cross-resistance with fluoroquinolone-resistant Staphylococcus aureus and E. coli isolates was observed. Measured MIC90 values were 4 and 8 μg/ml against a panel of contemporary multidrug-resistant isolates of Acinetobacter baumannii and E. coli, respectively. In addition, representative compounds exhibited greater antibacterial potency than the quinolones against obligate anaerobic species. Spontaneous mutation rates were low, with frequencies of resistance typically <10-8 against E. coli and A. baumannii at concentrations equivalent to 4-fold the MIC. Compound-resistant E. coli mutants that were isolated following serial passage were characterized by whole-genome sequencing and carried a single Arg38Leu amino acid substitution in the GyrA subunit of DNA gyrase. Preliminary in vitro safety data indicate that the series shows a promising therapeutic index and potential for low human ether-a-go-go-related gene (hERG) inhibition (50% inhibitory concentration [IC50], >100 μM). In summary, the compounds' distinct mechanism of action relative to the fluoroquinolones, whole-cell potency, low potential for resistance development, and favorable in vitro safety profile warrant their continued investigation as potential broad-spectrum antibacterial agents.
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Himelfarb MA, Lorenzutti AM, Litterio NJ, Zarazaga MDP, Aguilar-Sola MS, De Lucas JJ, San Andrés MI, Rubio-Langre S. Pharmacokinetic/pharmacodynamic analysis by Monte Carlo simulation of cefquinome in llamas, following intravenous, intramuscular and subcutaneous administration in serum and tissue cage fluid. Small Rumin Res 2017. [DOI: 10.1016/j.smallrumres.2017.02.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Amino acid substitutions of quinolone resistance determining regions in GyrA and ParC associated with quinolone resistance in Acinetobacter baumannii and Acinetobacter genomic species 13TU. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2012; 45:108-12. [DOI: 10.1016/j.jmii.2011.09.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2011] [Revised: 07/01/2011] [Accepted: 07/14/2011] [Indexed: 11/24/2022]
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Dalhoff A. Resistance surveillance studies: a multifaceted problem--the fluoroquinolone example. Infection 2012; 40:239-62. [PMID: 22460782 DOI: 10.1007/s15010-012-0257-2] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Accepted: 03/09/2012] [Indexed: 02/06/2023]
Abstract
INTRODUCTION This review summarizes data on the fluoroquinolone resistance epidemiology published in the previous 5 years. MATERIALS AND METHODS The data reviewed are stratified according to the different prescription patterns by either primary- or tertiary-care givers and by indication. Global surveillance studies demonstrate that fluoroquinolone- resistance rates increased in the past several years in almost all bacterial species except Staphylococcus pneumoniae and Haemophilus influenzae causing community-acquired respiratory tract infections (CARTIs), as well as Enterobacteriaceae causing community-acquired urinary tract infections. Geographically and quantitatively varying fluoroquinolone resistance rates were recorded among Gram-positive and Gram-negative pathogens causing healthcare-associated respiratory tract infections. One- to two-thirds of Enterobacteriaceae producing extended-spectrum β-lactamases (ESBLs) were fluoroquinolone resistant too, thus, limiting the fluoroquinolone use in the treatment of community- as well as healthcare-acquired urinary tract and intra-abdominal infections. The remaining ESBL-producing or plasmid-mediated quinolone resistance mechanisms harboring Enterobacteriaceae were low-level quinolone resistant. Furthermore, 10-30 % of H. influenzae and S. pneumoniae causing CARTIs harbored first-step quinolone resistance determining region (QRDR) mutations. These mutants pass susceptibility testing unnoticed and are primed to acquire high-level fluoroquinolone resistance rapidly, thus, putting the patient at risk. The continued increase in fluoroquinolone resistance affects patient management and necessitates changes in some current guidelines for the treatment of intra-abdominal infections or even precludes the use of fluoroquinolones in certain indications like gonorrhea and pelvic inflammatory diseases in those geographic areas in which fluoroquinolone resistance rates and/or ESBL production is high. Fluoroquinolone resistance has been selected among the commensal flora colonizing the gut, nose, oropharynx, and skin, so that horizontal gene transfer between the commensal flora and the offending pathogen as well as inter- and intraspecies recombinations contribute to the emergence and spread of fluoroquinolone resistance among pathogenic streptococci. Although interspecies recombinations are not yet the major cause for the emergence of fluoroquinolone resistance, its existence indicates that a large reservoir of fluoroquinolone resistance exists. Thus, a scenario resembling that of a worldwide spread of β-lactam resistance in pneumococci is conceivable. However, many resistance surveillance studies suffer from inaccuracies like the sampling of a selected patient population, restricted geographical sampling, and undefined requirements of the user, so that the results are biased. The number of national centers is most often limited with one to two participating laboratories, so that such studies are point prevalence but not surveillance studies. Selected samples are analyzed predominantly as either hospitalized patients or patients at risk or those in whom therapy failed are sampled; however, fluoroquinolones are most frequently prescribed by the general practitioner. Selected sampling results in a significant over-estimation of fluoroquinolone resistance in outpatients. Furthermore, the requirements of the users are often not met; the prescribing physician, the microbiologist, the infection control specialist, public health and regulatory authorities, and the pharmaceutical industry have diverse interests, which, however, are not addressed by different designs of a surveillance study. Tools should be developed to provide customer-specific datasets. CONCLUSION Consequently, most surveillance studies suffer from well recognized but uncorrected biases or inaccuracies. Nevertheless, they provide important information that allows the identification of trends in pathogen incidence and antimicrobial resistance.
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Affiliation(s)
- A Dalhoff
- Institute for Infection-Medicine, Christian-Albrechts University of Kiel and University Medical Center Schleswig-Holstein, Brunswiker Str. 4, 24105, Kiel, Germany.
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Activity of the investigational fluoroquinolone finafloxacin against ciprofloxacin-sensitive and -resistant Acinetobacter baumannii isolates. Antimicrob Agents Chemother 2010; 54:1613-5. [PMID: 20100879 DOI: 10.1128/aac.01637-09] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This study compared the activity of finafloxacin, a novel fluoroquinolone which shows enhanced activity under acidic pH, and that of ciprofloxacin against Acinetobacter baumannii under standard conditions (pH 7.2) and at a pH of 5.8. Overall, finafloxacin demonstrated superior activity to ciprofloxacin under acidic conditions. Furthermore, finafloxacin showed comparable activity to ciprofloxacin at pH 7.2. Hence, finafloxacin could be a promising new antimicrobial agent for the treatment of A. baumannii infections at acidic body compartments.
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Regalado NG, Martin G, Antony SJ. Acinetobacter lwoffii: bacteremia associated with acute gastroenteritis. Travel Med Infect Dis 2009; 7:316-7. [PMID: 19747669 DOI: 10.1016/j.tmaid.2009.06.001] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2009] [Accepted: 06/10/2009] [Indexed: 12/13/2022]
Abstract
Acinetobacter lwoffii is a non-fermentative aerobic gram-negative bacillus that is seen as a normal flora of the oropharynx and skin in approximately 25% of the healthy individuals. Due to its ubiquitous nature, it is a potential opportunistic pathogen in patients with impaired immune systems, and it has been identified as a cause of nosocomial infections like septicemia, pneumonia, meningitis, urinary tract infections, skin and wound infections. To our knowledge, this is the first case reported of a community acquired A. lwoffii bacteremia associated with gastroenteritis.
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Affiliation(s)
- Nora G Regalado
- Center for Infectious Diseases and Travel Medicine, El Paso, Texas 79902, USA
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Abstract
Bacteria of the genus Acinetobacter are ubiquitous in nature. These organisms were invariably susceptible to many antibiotics in the 1970s. Since that time, acinetobacters have emerged as multiresistant opportunistic nosocomial pathogens. The taxonomy of the genus Acinetobacter underwent extensive revision in the mid-1980s, and at least 32 named and unnamed species have now been described. Of these, Acinetobacter baumannii and the closely related unnamed genomic species 3 and 13 sensu Tjernberg and Ursing (13TU) are the most relevant clinically. Multiresistant strains of these species causing bacteraemia, pneumonia, meningitis, urinary tract infections and surgical wound infections have been isolated from hospitalised patients worldwide. This review provides an overview of the antimicrobial susceptibilities of Acinetobacter spp. in Europe, as well as the main mechanisms of antimicrobial resistance, and summarises the remaining treatment options for multiresistant Acinetobacter infections.
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Affiliation(s)
- M Van Looveren
- Department of Medical Microbiology, University Hospital Antwerp, UA, Antwerp, Belgium.
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Goldstein EJC, Conrads G, Citron DM, Merriam CV, Warren Y, Tyrrell K. In vitro activity of gemifloxacin compared to seven other oral antimicrobial agents against aerobic and anaerobic pathogens isolated from antral sinus puncture specimens from patients with sinusitis. Diagn Microbiol Infect Dis 2002; 42:113-8. [PMID: 11858906 DOI: 10.1016/s0732-8893(01)00341-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Using a microbroth method for aerobes and agar dilution for anaerobes, we studied the comparative in vitro activity of gemifloxacin, three fluoroquinolones, two macrolides and two beta-lactams, against 207 aerobic and 162 anaerobic antral sinus puncture isolates. Gemifloxacin was active at < or = 0.25 ug/mL against 198/207 [96%] aerobes and 127/162 [78%] anaerobes or 325/369 [88%] of all isolates and was the most active quinolone on a weight basis against Gram-positive organisms. All Haemophilus and Moraxella species were susceptible to < or =0.06 ug/mL of gemifloxacin. Thirty-five anaerobic isolates [35/162, 22%] required > or =0.5 ug/mL of gemifloxacin for inhibition, including all Prevotella species [all except one strain of P. bivia were susceptible to < or = 2 ug/mL] and occasional strains of Bacteroides uniformis, Bacteroides fragilis, Bilophila wadsworthia, Peptostreptococcus magnus, Peptostreptococcus micros, Propionibacterium acnes, and Veillonella species. All fusobacteria were susceptible to < or =0.25 ug/mL of gemifloxacin. Based on our in vitro study results, we conclude that gemifloxacin may offer a therapeutic alternative for sinus infections.
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Affiliation(s)
- Ellie J C Goldstein
- R.M. Alden Research Laboratory, Santa Monica-UCLA Medical Center, Santa Monica, CA 90404, USA.
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Abstract
Gemifloxacin is a fluoroquinolone antibacterial agent which has an enhanced affinity for topoisomerase i.v.. It has potent activity against most Gram-positive bacteria, particularly Streptococcus pneumoniae. Gemifloxacin is over 30-fold more active than ciprofloxacin and 4- to 8-fold more active than moxifloxacin against this pathogen. Gemifloxacin has excellent activity against Haemophilus influenzae and Moraxella catarrhalis, and is unaffected by beta-lactamase production. It is generally 2-fold less active than ciprofloxacin against most Enterobacteriaceae. Atypical respiratory pathogens (Legionella, Mycoplasma and Chlamydia spp.) are highly susceptible to gemifloxacin. Preliminary results from phase II trials show that oral gemifloxacin 320 mg/day produced bacteriological responses of 94.7% in patients with acute exacerbations of chronic bronchitis and 95% of patients with uncomplicated urinary tract infections. Adverse events included nausea, abdominal pain, headache and mild rash in patients and healthy volunteers treated with gemifloxacin 320 mg/day. Gemifloxacin has a low potential for mild phototoxicity (comparable to that of ciprofloxacin).
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Affiliation(s)
- M N Lowe
- Adis International Limited, Mairangi Bay, Auckland, New Zealand.
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