Ricci, Vito, Piddock, Laura J. V.
Objectives The aim of this study was to understand the role of ramA in conferring multidrug resistance (MDR) in Salmonella enterica serovar Typhimurium. Methods Two phenotypically distinct isogenic...
Elviss, Nicola C., Williams, Lisa K., Jørgensen, Frieda, Chisholm, Stephanie A., Lawson, Andrew J., Swift, Craig, ...
Background The aim of this study was to investigate the effect of amoxicillin therapy of poultry flocks upon the persistence of commensal Campylobacter spp. and the incidence of antibiotic...
Blair, Jessica M. A., La Ragione, Roberto M., Woodward, Martin J., Piddock, Laura J. V.
Objectives AcrA can function as the periplasmic adaptor protein (PAP) in several RND tripartite efflux pumps, of which AcrAB-TolC is considered the most important. This system confers innate multiple...
Bailey, Andrew M., Constantinidou, Chrystala, Ivens, Al, Garvey, Mark I., Webber, Mark A., Coldham, Nick, ...
Objectives The use of triclosan within various environments has been linked to the development of multiple drug resistance (MDR) through the increased expression of efflux pumps such as AcrAB–TolC....
Triclosan resistance in Salmonella enterica serovar Typhimurium (2008)
Webber, Mark A., Randall, Luke P., Cooles, Susan, Woodward, Martin J., Piddock, Laura J. V.
Objectives The aim of this study was to characterize the mechanisms of resistance to triclosan in Salmonella enterica serovar Typhimurium. Methods Mutants resistant to triclosan were selected from...
Proteomic analysis of triclosan resistance in Salmonella enterica serovar Typhimurium (2008)
Webber, Mark A., Coldham, Nick G., Woodward, Martin J., Piddock, Laura J. V.
Objectives The aim of this study was to determine and compare the proteomes of three triclosan-resistant mutants of Salmonella enterica serovar Typhimurium in order to identify proteins involved in...
Karatzas, Kimon A. G., Webber, Mark A., Jorgensen, Frieda, Woodward, Martin J., Piddock, Laura J. V., Humphrey, Tom J.
Objectives To study how disinfectants affect antimicrobial susceptibility and phenotype of Salmonella enterica serovar Typhimurium SL1344. Methods Wild-type strain SL1344 and its isogenic gyrA...
Avrain, Laetitia, Garvey, Mark, Mesaros, Narcisa, Glupczynski, Youri, Mingeot-Leclercq, Marie-Paule, Piddock, Laura J. V., ...
Objectives Does exposure to subinhibitory concentrations of quinolones favour overexpression of efflux pumps or selection of target site mutations? Methods ATCC 49619 (fully susceptible) and SP32...
Bacterial efflux pump inhibitors from natural sources (2007)
Stavri, Michael, Piddock, Laura J. V., Gibbons, Simon
The rapid spread of bacteria expressing multidrug resistance (MDR) has necessitated the discovery of new antibacterials and resistance-modifying agents. Since the initial discovery of bacterial...
Webber, Mark, Buckley, Anthony M., Randall, Luke P., Woodward, Martin J., Piddock, Laura J. V.
Objectives: To determine the contribution of the AcrAB efflux system to cyclohexane tolerance in Salmonella enterica. Methods: The expression of the efflux pump gene, acrB, and regulators marA and...
Effect of fluoroquinolone exposure on the proteome of Salmonella enterica serovar Typhimurium (2006)
Coldham, Nick G., Randall, Luke P., Piddock, Laura J. V., Woodward, Martin J.
Objectives: The physiological response of Salmonella enterica serovar Typhimurium to fluoroquinolone antibiotics was investigated using proteomic methods. Methods: Proteomes were prepared from strain...
Bacterial efflux pump inhibitors from natural sources (2006)
Stavri, Michael, Piddock, Laura J. V., Gibbons, Simon
The rapid spread of bacteria expressing multidrug resistance (MDR) has necessitated the discovery of new antibacterials and resistance-modifying agents. Since the initial discovery of bacterial...
Effect of fluoroquinolone exposure on the proteome of Salmonella enterica serovar Typhimurium (2006)
Coldham, Nick G., Randall, Luke P., Piddock, Laura J. V., Woodward, Martin J.
Objectives: The physiological response of Salmonella enterica serovar Typhimurium to fluoroquinolone antibiotics was investigated using proteomic methods. Methods: Proteomes were prepared from strain...
Randall, Luke P., Eaves, Deborah J., Cooles, Sue W., Ricci, V., Buckley, Antony, Woodward, Martin J., ...
Objectives: To determine the efficacy of enrofloxacin (Baytril) in chickens in eradicating three different resistance phenotypes of Salmonella enterica and to examine the resistance mechanisms of...
Randall, Luke P., Eaves, Deborah J., Cooles, Sue W., Ricci, V., Buckley, Antony, Woodward, Martin J., ...
Objectives: To determine the efficacy of enrofloxacin (Baytril) in chickens in eradicating three different resistance phenotypes of Salmonella enterica and to examine the resistance mechanisms of...
Delsol, Anne A., Sunderland, Julie, Woodward, Martin J., Pumbwe, Lillian, Piddock, Laura J. V., Roe, John M.
Objective: The effect of a single 5 day enrofloxacin treatment on the native Campylobacter coli population in conventionally weaned 5-week-old pigs was investigated. Materials: Twelve pigs were split...
Delsol, Anne A., Sunderland, Julie, Woodward, Martin J., Pumbwe, Lillian, Piddock, Laura J. V., Roe, John M.
Objective: The effect of a single 5 day enrofloxacin treatment on the native Campylobacter coli population in conventionally weaned 5-week-old pigs was investigated. Materials: Twelve pigs were split...
Pumbwe, Lilian, Randall, Luke P., Woodward, Martin J., Piddock, Laura J. V.
Aims: In Escherichia coli, increased expression of efflux pumps and/or decreased expression of porins can confer multiple antibiotic resistance (MAR), causing resistance to at least three unrelated...
Griggs, Deborah J., Marona, Herida, Piddock, Laura J. V.
Fluoroquinolone-resistant mutants were selected from Staphylococcus aureus NCTC 8532 (F77), and two GrlA mutants of F77 (F193 and F194) with moxifloxacin, sparfloxacin, ofloxacin, grepafloxacin,...
Activity of faropenem and imipenem for ciprofloxacin-resistant bacteria (2003)
Piddock, Laura J. V., Johnson, M. M., Webber, Mark A.
Aim: To determine whether an association exists between ciprofloxacin and faropenem resistance in bacteria including multiply drug-resistant isolates. Methods: The MICs were determined for 150...
Griggs, Deborah J., Marona, Herida, Piddock, Laura J. V.
Fluoroquinolone-resistant mutants were selected from Staphylococcus aureus NCTC 8532 (F77), and two GrlA mutants of F77 (F193 and F194) with moxifloxacin, sparfloxacin, ofloxacin, grepafloxacin,...
Activity of faropenem and imipenem for ciprofloxacin-resistant bacteria (2003)
Piddock, Laura J. V., Johnson, M. M., Webber, Mark A.
Aim: To determine whether an association exists between ciprofloxacin and faropenem resistance in bacteria including multiply drug-resistant isolates. Methods: The MICs were determined for 150...
Fluoroquinolone resistance in Haemophilus influenzae (2003)
Elliott, Eugenne, Oosthuizen, Deon, Johnson, Maggie M, Piddock, Laura J. V.
Piddock, Laura J. V., Ricci, Vito, Pumbwe, Lilian, Everett, Martin J., Griggs, Deborah J.
Consecutive isolates of quinolone-resistant campylobacter isolated over a 5 year period (1990–1995) from the faeces of patients with enteritis in Plymouth, UK, were examined for the epidemiology of...
Fluoroquinolone resistance in Haemophilus influenzae (2003)
Elliott, Eugenne, Oosthuizen, Deon, Johnson, Maggie M, Piddock, Laura J. V.
Griggs, Deborah J., Marona, Herida, Piddock, Laura J. V.
Fluoroquinolone-resistant mutants were selected from Staphylococcus aureus NCTC 8532 (F77), and two GrlA mutants of F77 (F193 and F194) with moxifloxacin, sparfloxacin, ofloxacin, grepafloxacin,...
Activity of faropenem and imipenem for ciprofloxacin-resistant bacteria (2003)
Piddock, Laura J. V., Johnson, M. M., Webber, Mark A.
Aim: To determine whether an association exists between ciprofloxacin and faropenem resistance in bacteria including multiply drug-resistant isolates. Methods: The MICs were determined for 150...
Fluoroquinolone resistance in Haemophilus influenzae (2003)
Elliott, Eugenne, Oosthuizen, Deon, Johnson, Maggie M, Piddock, Laura J. V.
Piddock, Laura J. V., Ricci, Vito, Pumbwe, Lilian, Everett, Martin J., Griggs, Deborah J.
Consecutive isolates of quinolone-resistant campylobacter isolated over a 5 year period (1990-1995) from the faeces of patients with enteritis in Plymouth, UK, were examined for the epidemiology of...
Piddock, Laura J. V., Ricci, Vito, Pumbwe, Lilian, Everett, Martin J., Griggs, Deborah J.
Consecutive isolates of quinolone-resistant campylobacter isolated over a 5 year period (1990-1995) from the faeces of patients with enteritis in Plymouth, UK, were examined for the epidemiology of...
Accumulation of five fluoroquinolones by Mycobacterium tuberculosis H37Rv (2001)
Piddock, Laura J. V., Ricci, Vito
The accumulation of ciprofloxacin, norfloxacin, moxifloxacin, levofloxacin and ofloxacin by Mycobacterium tuberculosis H37Rv was determined with a modified fluorescence method. The time to achieve a...
Piddock, Laura J. V., Jin, Yu Fang, Griggs, Deborah J.
Ten novel fluoroquinolones, with similar chemical structures but differing antibacterial activities and hydrophobicities, were studied to evaluate the role of the physical properties of quinolones on...
Piddock, Laura J. V., Ricci, V., Stanley , K., Jones, Keith
A retrospective study of 96 Campylobacter jejuni isolated from farm animals and the environment showed that most were less susceptible than the NCTC type strain to nalidixic acid (MICs 4–32 mg/L),...
Piddock, Laura J. V., Ricci, V., Stanley, K., Jones, K.
A retrospective study of 96 Campylobacter jejuni isolated from farm animals and the environment showed that most were less susceptible than the NCTC type strain to nalidixic acid (MICs 4–32 mg/L),...
Accumulation of KRM-1648 by Mycobacterium aurum and Mycobacterium tuberculosis (2000)
Piddock, Laura J. V., Ricci, Vito
After exposure to 2 mg/L 14C-labelled KRM-1648 (a new broad-spectrum benzoxazinorifamycin antibiotic) for 5 min, a steady-state concentration of 31.3 ± 3 ng/mg cells KRM-1648 and 12.6 ± 0.3 ng/mg...
Piddock, Laura J. V., Williams, Kerstin J., Ricci, Vito
The characteristics of the accumulation of 2 mg/L [14C]rifampicin by wild-type strains of Mycobacterium aurum (A+), Mycobacterium smegmatis (mc2155) and Mycobacterium tuberculosis (H37Rv) were...
Quinolone accumulation by Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli (1999)
Piddock, Laura J. V., Ricci, V., Asuquo, Anne E.
The accumulation of nalidixic acid and 14 fluoroquinolones over a range of external drug concentrations (10–100 mg/L; c. 25–231 µM) into intact cells of Escherichia coli KL-16, Staphylococcus...
Antimicrobial activity and accumulation of moxifloxacin in quinolone-susceptible bacteria (1999)
Piddock, Laura J. V., Jin, Yu Fang
The antibacterial activity of moxifloxacin, compared with that of ciprofloxacin, was determined for five strains of Staphylococcus aureus, including one NorA-overproducing strain, two...
Ciprofloxacin resistant Campylobacter spp. in humans: an epidemiological and laboratory study (1996)
Gaunt, P. N., Piddock, Laura J. V.
From the end of April 1991 until the end of 1991, 2209 isolates of Campylobacter spp. have been collected in Plymouth PHL of which 91(4.1%) were resistant to ciprofloxacin. None of the 91...
Quinolone resistance and Campylobacter spp. (1995)
Campylobacter are a frequent cause of diarrhoea in man. The in-vitro susceptibility of all species to the fluoroquinolones and the good response observed in early clinical trials has led to the...
Piddock, Laura J. V., Jin, Yu Fang, Turner, H. L.
The activity of six cephalosporins, six penicillins and one monobactam combined with BRL 42715, clavulanic acid, sulbactam or tazobactam at 0·1, 0·5, 1, 2, 5 and 10 mg/L was determined for 45...
Piddock, Laura J. V., Panchal, S., Norte, V.
For rufloxacin MF961, ofloxacin and fleroxacin the inhibition of DNA synthesis, intracellular accumulation, optimum bactericidal concentration (OBC) and killing kinetics at the OBC for...
Asuquo, Anne E., Piddock, Laura J. V.
The accumulation of fifteen quinolone antimicrobial agents (nalidixic acid, eight mono-fluorinated agents, three di-fluorinated agents and three tri-fluorinated agents) by Escherichia coli KL16,...
Piddock, Laura J. V., Hall, M. C., Walters, R. N.
The NCTC type strains of Escherichia coli, Enterobacter cloacae, Serratia marcescnes and Klebsiella pneumoniae were exposed to 3, 5 and 10 × MIC of nalidixic acid, enoxacin, ciprofloxacin, PD 117596...
Piddock, Laura J. V., Traynor, E. A.
Twenty-five strains of Enterobacteriaceae (five each of Enterobacter cloacae, Citrobacter freundii, Serratia marcescens, Morganella morganii and Providencia stuartii) and five strains of Pseudomonas...
Piddock, Laura J. V., Traynor, E. A.
Twenty-five strains of Enterobacteriaceae (five each of Enterobacter cloacae, Citrobacter freundii, Serratia marcescens, Morganella morganii, and Providencia stuartii) were exposed to FCE 22101 in...
Selection and characterization of cefepime-resistant Gram-negative bacteria (1991)
Piddock, Laura J. V., Griggs, D. J.
The NCTC type strains and four clinical isolates of Enterobacter cloacae, Citrobacter freundii, Serratia marcescens, Morganella morganii, Providencia stuartii and Pseudomonas aeruginosa were exposed,...
Johnson, M. M., Hill, S. L., Piddock, Laura J. V.
The in vitro activities of erythromycin, azithromycin, and clarithromycin against 178 clinical isolates from the lower respiratory tract of patients with chronic obstructive pulmonary disease were...
Accumulation of Norfloxacin by Bacteroides fragilis
Ricci, Vito, Piddock, Laura J. V.
The accumulation of norfloxacin by Bacteroides fragilis NCTC 9343 was determined by the modified fluorescence method. The time required to achieve a steady-state concentration (SSC) after allowing B....
Two Efflux Systems Expressed Simultaneously in Multidrug-Resistant Pseudomonas aeruginosa
Pumbwe, Lilian, Piddock, Laura J. V.
Simultaneous overexpression of MexAB-OprM and MexEF-OprN was demonstrated for a multiply antibiotic-resistant clinical isolate of Pseudomonas aeruginosa (G49). G49 also had decreased expression of...
Characterization of Fluoroquinolone Resistance among Veterinary Isolates of Avian Escherichia coli
White, David G., Piddock, Laura J. V., Maurer, John J., Zhao, Shaohua, Ricci, Vito, Thayer, Stephan G.
Fluoroquinolone-resistant avian Escherichia coli isolates from northern Georgia were investigated for gyrA and parC mutations. All isolates contained a mutation in GyrA replacing Ser83 with Leu;...
Webber, Mark A., Piddock, Laura J. V.
The amount of acrB, marA, and soxS mRNA was determined in 36 fluoroquinolone-resistant E. coli from humans and animals, 27 of which displayed a multiple-resistance phenotype. acrB mRNA was elevated...
Piddock, Laura J. V., White, David G., Gensberg, Karl, Pumbwe, Lilian, Griggs, Deborah J.
The mechanism of multiple antibiotic resistance in six isolates of Salmonella enterica serovar Typhimurium recovered from a patient treated with ciprofloxacin was studied to investigate the role of...
Accumulation of Norfloxacin by Mycobacterium aurum and Mycobacterium smegmatis
Williams, Kerstin J., Chung, Gavin A. C., Piddock, Laura J. V.
The modified fluorescence method was used to determine the accumulation of norfloxacin by Mycobacterium aurum A+ and Mycobacterium smegmatis mc2155. By using an exogenous norfloxacin concentration of...
Piddock, Laura J. V., Johnson, M., Ricci, V., Hill, S. L.
The activities of six new fluoroquinolones (moxifloxacin, grepafloxacin, gatifloxacin, trovafloxacin, clinafloxacin, and levofloxacin) compared with those of sparfloxacin and ciprofloxacin with or...
Novel Ciprofloxacin-Resistant, Nalidixic Acid-Susceptible Mutant of Staphylococcus aureus
Piddock, Laura J. V., Jin, Yu Fang, Webber, Mark A., Everett, Martin J.
A ciprofloxacin-resistant, nalidixic acid-susceptible mutant of Staphylococcus aureus (F145) contained no mutations within gyrA, gyrB, grlA, and grlB or within norA or its promoter region. MICs and...
Piddock, Laura J. V., Johnson, Maggie M., Simjee, S., Pumbwe, L.
Thirty-four ciprofloxacin-resistant (MIC ≥ 2 μg/ml) and 12 ciprofloxacin-susceptible clinical isolates of Streptococcus pneumoniae were divided into four groups based upon susceptibility to...
Accumulation of 10 Fluoroquinolones by Wild-Type or Efflux Mutant Streptococcus pneumoniae
Piddock, Laura J. V., Johnson, M. M.
A method for measuring fluoroquinolone accumulation by Streptococcus pneumoniae was rigorously examined. The accumulation of ciprofloxacin, clinafloxacin, gatifloxacin, grepafloxacin, levofloxacin,...
Eaves, Deborah J., Liebana, Ernesto, Woodward, Martin J., Piddock, Laura J. V.
Denaturing high-performance liquid chromatography (DHPLC) was evaluated as a rapid screening and identification method for DNA sequence variation detection in the quinolone resistance-determining...
Ricci, Vito, Peterson, Marnie L., Rotschafer, John C., Wexler, Hannah, Piddock, Laura J. V.
Twelve laboratory mutants and 32 ciprofloxacin-resistant isolates of Bacteroides fragilis were examined for the mechanism(s) of fluoroquinolone resistance. Five mutants had mutations in gyrA. One...
Eaves, Deborah J., Ricci, Vito, Piddock, Laura J. V.
Comparative reverse transcription-PCR in combination with denaturing high-pressure liquid chromatography analysis was used to determine the levels of expression of soxS, marA, acrF, acrB, and acrD in...
Eaves, Deborah J., Randall, Luke, Gray, Douglas T., Buckley, Antony, Woodward, Martin J., White, Allan P., ...
Salmonella enterica isolates (n = 182) were examined for mutations in the quinolone resistance-determining region of gyrA, gyrB, parC, and parE. The frequency, location, and type of GyrA substitution...
Humphrey, Tom J., Jørgensen, Frieda, Frost, Jennifer A., Wadda, Haddy, Domingue, Gil, Elviss, Nicola C., ...
Five commercial broiler chicken flocks were treated with either difloxacin or enrofloxacin for a clinically relevant infection, as instructed by a veterinarian. Campylobacters were isolated from...
Griggs, Deborah J., Johnson, Maggie M., Frost, Jennifer A., Humphrey, Tom, Jørgensen, Frieda, Piddock, Laura J. V.
Five commercial broiler flocks were treated with a fluoroquinolone for a clinically relevant infection. Fresh feces from individual chickens and environmental samples were cultured for campylobacters...
Evidence for Multiple-Antibiotic Resistance in Campylobacter jejuni Not Mediated by CmeB or CmeF
Pumbwe, Lilian, Randall, Luke P., Woodward, Martin J., Piddock, Laura J. V.
An efflux system, CmeABC, in Campylobacter jejuni was previously described, and a second efflux system, CmeDEF, has now been identified. The substrates of CmeDEF include ampicillin, ethidium bromide,...
Webber, Mark A., Talukder, Ashraf, Piddock, Laura J. V.
Fluoroquinolone-resistant Escherichia coli isolates which overexpressed acrB and had a substitution at amino acid 45 of AcrR were complemented with wild-type acrR. Complementation led to increased...
Marrer, Estelle, Satoh, A. Tatsuo, Johnson, Margaret M., Piddock, Laura J. V., Page, Malcolm G. P.
Streptococcus pneumoniae M22 is a multidrug-resistant mutant selected after exposure of capsulated wild-type S. pneumoniae NCTC 7465 (strain M4) to ciprofloxacin. DNA microarray analysis comparing...
Ricci, Vito, Tzakas, Peter, Buckley, Anthony, Coldham, Nick C., Piddock, Laura J. V.
It has been proposed that lack of a functional efflux system(s) will lead to a lower frequency of selection of resistance to fluoroquinolones and other antibiotics. We constructed five strains of...
Marrer, Estelle, Schad, Karen, Satoh, Andreas T., Page, Malcolm G. P., Johnson, Maggie M., Piddock, Laura J. V.
The multidrug-resistant mutant Streptococcus pneumoniae M22 constitutively overexpresses two genes (patA and patB) that encode proteins homologous to known efflux proteins belonging to the ABC...
Medium Plays a Role in Determining Expression of acrB, marA, and soxS in Escherichia coli
Bailey, Andrew M., Webber, Mark A., Piddock, Laura J. V.
Analysis of expression of acrB, marA, and soxS in rich and minimal media, at early and late logarithmic growth phases, showed that acrB had increased expression in minimal medium compared to rich...
Evidence for Multiple-Antibiotic Resistance in Campylobacter jejuni Not Mediated by CmeB or CmeF
Pumbwe, Lilian, Randall, Luke P., Woodward, Martin J., Piddock, Laura J. V.
Johnson, M. M., Hill, S. L., Piddock, Laura J. V.
The in vitro activities of erythromycin, azithromycin, and clarithromycin against 178 clinical isolates from the lower respiratory tract of patients with chronic obstructive pulmonary disease were...
Accumulation of Norfloxacin by Bacteroides fragilis
Ricci, Vito, Piddock, Laura J. V.
The accumulation of norfloxacin by Bacteroides fragilis NCTC 9343 was determined by the modified fluorescence method. The time required to achieve a steady-state concentration (SSC) after allowing B....
Two Efflux Systems Expressed Simultaneously in Multidrug-Resistant Pseudomonas aeruginosa
Pumbwe, Lilian, Piddock, Laura J. V.
Simultaneous overexpression of MexAB-OprM and MexEF-OprN was demonstrated for a multiply antibiotic-resistant clinical isolate of Pseudomonas aeruginosa (G49). G49 also had decreased expression of...
Characterization of Fluoroquinolone Resistance among Veterinary Isolates of Avian Escherichia coli
White, David G., Piddock, Laura J. V., Maurer, John J., Zhao, Shaohua, Ricci, Vito, Thayer, Stephan G.
Fluoroquinolone-resistant avian Escherichia coli isolates from northern Georgia were investigated for gyrA and parC mutations. All isolates contained a mutation in GyrA replacing Ser83 with Leu;...
Webber, Mark A., Piddock, Laura J. V.
The amount of acrB, marA, and soxS mRNA was determined in 36 fluoroquinolone-resistant E. coli from humans and animals, 27 of which displayed a multiple-resistance phenotype. acrB mRNA was elevated...
Piddock, Laura J. V., White, David G., Gensberg, Karl, Pumbwe, Lilian, Griggs, Deborah J.
The mechanism of multiple antibiotic resistance in six isolates of Salmonella enterica serovar Typhimurium recovered from a patient treated with ciprofloxacin was studied to investigate the role of...
Accumulation of Norfloxacin by Mycobacterium aurum and Mycobacterium smegmatis
Williams, Kerstin J., Chung, Gavin A. C., Piddock, Laura J. V.
The modified fluorescence method was used to determine the accumulation of norfloxacin by Mycobacterium aurum A+ and Mycobacterium smegmatis mc2155. By using an exogenous norfloxacin concentration of...
Piddock, Laura J. V., Johnson, M., Ricci, V., Hill, S. L.
The activities of six new fluoroquinolones (moxifloxacin, grepafloxacin, gatifloxacin, trovafloxacin, clinafloxacin, and levofloxacin) compared with those of sparfloxacin and ciprofloxacin with or...
Novel Ciprofloxacin-Resistant, Nalidixic Acid-Susceptible Mutant of Staphylococcus aureus
Piddock, Laura J. V., Jin, Yu Fang, Webber, Mark A., Everett, Martin J.
A ciprofloxacin-resistant, nalidixic acid-susceptible mutant of Staphylococcus aureus (F145) contained no mutations within gyrA, gyrB, grlA, and grlB or within norA or its promoter region. MICs and...
Piddock, Laura J. V., Johnson, Maggie M., Simjee, S., Pumbwe, L.
Thirty-four ciprofloxacin-resistant (MIC ≥ 2 μg/ml) and 12 ciprofloxacin-susceptible clinical isolates of Streptococcus pneumoniae were divided into four groups based upon susceptibility to...
Accumulation of 10 Fluoroquinolones by Wild-Type or Efflux Mutant Streptococcus pneumoniae
Piddock, Laura J. V., Johnson, M. M.
A method for measuring fluoroquinolone accumulation by Streptococcus pneumoniae was rigorously examined. The accumulation of ciprofloxacin, clinafloxacin, gatifloxacin, grepafloxacin, levofloxacin,...
Eaves, Deborah J., Liebana, Ernesto, Woodward, Martin J., Piddock, Laura J. V.
Denaturing high-performance liquid chromatography (DHPLC) was evaluated as a rapid screening and identification method for DNA sequence variation detection in the quinolone resistance-determining...
Ricci, Vito, Peterson, Marnie L., Rotschafer, John C., Wexler, Hannah, Piddock, Laura J. V.
Twelve laboratory mutants and 32 ciprofloxacin-resistant isolates of Bacteroides fragilis were examined for the mechanism(s) of fluoroquinolone resistance. Five mutants had mutations in gyrA. One...
Eaves, Deborah J., Ricci, Vito, Piddock, Laura J. V.
Comparative reverse transcription-PCR in combination with denaturing high-pressure liquid chromatography analysis was used to determine the levels of expression of soxS, marA, acrF, acrB, and acrD in...
Eaves, Deborah J., Randall, Luke, Gray, Douglas T., Buckley, Antony, Woodward, Martin J., White, Allan P., ...
Salmonella enterica isolates (n = 182) were examined for mutations in the quinolone resistance-determining region of gyrA, gyrB, parC, and parE. The frequency, location, and type of GyrA substitution...
Humphrey, Tom J., Jørgensen, Frieda, Frost, Jennifer A., Wadda, Haddy, Domingue, Gil, Elviss, Nicola C., ...
Five commercial broiler chicken flocks were treated with either difloxacin or enrofloxacin for a clinically relevant infection, as instructed by a veterinarian. Campylobacters were isolated from...
Griggs, Deborah J., Johnson, Maggie M., Frost, Jennifer A., Humphrey, Tom, Jørgensen, Frieda, Piddock, Laura J. V.
Five commercial broiler flocks were treated with a fluoroquinolone for a clinically relevant infection. Fresh feces from individual chickens and environmental samples were cultured for campylobacters...
Evidence for Multiple-Antibiotic Resistance in Campylobacter jejuni Not Mediated by CmeB or CmeF
Pumbwe, Lilian, Randall, Luke P., Woodward, Martin J., Piddock, Laura J. V.
An efflux system, CmeABC, in Campylobacter jejuni was previously described, and a second efflux system, CmeDEF, has now been identified. The substrates of CmeDEF include ampicillin, ethidium bromide,...
Webber, Mark A., Talukder, Ashraf, Piddock, Laura J. V.
Fluoroquinolone-resistant Escherichia coli isolates which overexpressed acrB and had a substitution at amino acid 45 of AcrR were complemented with wild-type acrR. Complementation led to increased...
Marrer, Estelle, Satoh, A. Tatsuo, Johnson, Margaret M., Piddock, Laura J. V., Page, Malcolm G. P.
Streptococcus pneumoniae M22 is a multidrug-resistant mutant selected after exposure of capsulated wild-type S. pneumoniae NCTC 7465 (strain M4) to ciprofloxacin. DNA microarray analysis comparing...
Ricci, Vito, Tzakas, Peter, Buckley, Anthony, Coldham, Nick C., Piddock, Laura J. V.
It has been proposed that lack of a functional efflux system(s) will lead to a lower frequency of selection of resistance to fluoroquinolones and other antibiotics. We constructed five strains of...
Marrer, Estelle, Schad, Karen, Satoh, Andreas T., Page, Malcolm G. P., Johnson, Maggie M., Piddock, Laura J. V.
The multidrug-resistant mutant Streptococcus pneumoniae M22 constitutively overexpresses two genes (patA and patB) that encode proteins homologous to known efflux proteins belonging to the ABC...
Medium Plays a Role in Determining Expression of acrB, marA, and soxS in Escherichia coli
Bailey, Andrew M., Webber, Mark A., Piddock, Laura J. V.
Analysis of expression of acrB, marA, and soxS in rich and minimal media, at early and late logarithmic growth phases, showed that acrB had increased expression in minimal medium compared to rich...
Evidence for Multiple-Antibiotic Resistance in Campylobacter jejuni Not Mediated by CmeB or CmeF
Pumbwe, Lilian, Randall, Luke P., Woodward, Martin J., Piddock, Laura J. V.
Clinically Relevant Chromosomally Encoded Multidrug Resistance Efflux Pumps in Bacteria
Efflux pump genes and proteins are present in both antibiotic-susceptible and antibiotic-resistant bacteria. Pumps may be specific for one substrate or may transport a range of structurally...
Randall, Luke P., Cooles, Sue W., Coldham, Nick C., Stapleton, Ken S., Piddock, Laura J. V., Woodward, Martin J.
We hypothesized that higher doses of fluoroquinolones for a shorter duration could maintain efficacy (as measured by reduction in bacterial count) while reducing selection in chickens of bacteria...
Karatzas, Kimon A. G., Randall, Luke P., Webber, Mark, Piddock, Laura J. V., Humphrey, Tom J., Woodward, Martin J., ...
In previous work, Salmonella enterica serovar Typhimurium strain SL1344 was exposed to sublethal concentrations of three widely used farm disinfectants in daily serial passages for 7 days in an...
Garvey, Mark I., Piddock, Laura J. V.
One way to combat multidrug-resistant microorganisms is the use of efflux pump inhibitors (EPIs). Spontaneous mutants resistant to the EPI reserpine selected from Streptococcus pneumoniae NCTC 7465...
Bailey, Andrew M., Paulsen, Ian T., Piddock, Laura J. V.
Salmonella enterica serovar Typhimurium SL1344, in which efflux pump genes (acrB, acrD, acrF, tolC) or regulatory genes thereof (marA, soxS, ramA) were inactivated, was grown in the presence of 240...
Reduced Fluoroquinolone Susceptibility in Salmonella enterica Isolates from Travelers, Finland
Lindgren, Marianne M., Kotilainen, Pirkko, Huovinen, Pentti, Hurme, Saija, Lukinmaa, Susanna, Webber, Mark A., ...
We tested the fluoroquinolone susceptibility of 499 Salmonella enterica isolates collected from travelers returning to Finland during 2003–2007. Among isolates from travelers to Thailand and...