scholarly journals Assessment of Persistence of Bartonella henselae in Ctenocephalides felis

2013 ◽  
Vol 79 (23) ◽  
pp. 7439-7444 ◽  
Author(s):  
Emilie Bouhsira ◽  
Michel Franc ◽  
Henri-Jean Boulouis ◽  
Philippe Jacquiet ◽  
Isabelle Raymond-Letron ◽  
...  
Keyword(s):  
Bartonella Henselae ◽  
Membrane System ◽  
Ctenocephalides Felis ◽  
Artificial Membrane ◽  
Cat Flea ◽  
Infected Blood ◽  
Content Type ◽  
Entire Life ◽  
Kinetics Of ◽  
Fastidious Bacterium

ABSTRACTBartonella henselae(Rhizobiales:Bartonellaceae) is a Gram-negative fastidious bacterium of veterinary and zoonotic importance. The cat fleaCtenocephalides felis(Siphonaptera: Pulicidae) is the main recognized vector ofB. henselae, and transmission among cats and humans occurs mainly through infected flea feces. The present study documents the use of a quantitative molecular approach to follow the daily kinetics ofB. henselaewithin the cat flea and its excreted feces after exposure to infected blood for 48 h in an artificial membrane system.B. henselaeDNA was detected in both fleas and feces for the entire life span of the fleas (i.e., 12 days) starting from 24 h after initiation of the blood meal.

scholarly journals The Cat Flea (Ctenocephalides felis) Immune Deficiency Signaling Pathway Regulates Rickettsia typhi Infection

2017 ◽  
Vol 86 (1) ◽  
Author(s):  
Sherri A. Rennoll ◽  
Kristen E. Rennoll-Bankert ◽  
Mark L. Guillotte ◽  
Stephanie S. Lehman ◽  
Timothy P. Driscoll ◽  
...  
Keyword(s):  
Gene Expression ◽  
Immune Deficiency ◽  
Ctenocephalides Felis ◽  
Spotted Fever Group ◽  
Rickettsia Typhi ◽  
Rickettsial Infection ◽  
Cat Flea ◽  
Content Type ◽  
Imd Pathway ◽  
Pathway Activation

ABSTRACTRickettsiaspecies are obligate intracellular bacteria with both conserved and lineage-specific strategies for invading and surviving within eukaryotic cells. One variable component ofRickettsiabiology involves arthropod vectors: for instance, typhus group rickettsiae are principally vectored by insects (i.e., lice and fleas), whereas spotted fever group rickettsiae are exclusively vectored by ticks. For flea-borneRickettsia typhi, the etiological agent of murine typhus, research on vertebrate host biology is facilitated using cell lines and animal models. However, due to the lack of any stable flea cell line or a published flea genome sequence, little is known regardingR. typhibiology in flea vectors that, importantly, do not suffer lethality due toR. typhiinfection. To address if fleas combat rickettsial infection, we characterized the cat flea (Ctenocephalides felis) innate immune response toR. typhi. Initially, we determined thatR. typhiinfectsDrosophilacells and increases antimicrobial peptide (AMP) gene expression, indicating immune pathway activation. While bioinformatics analysis of theC. felistranscriptome identified homologs to all of theDrosophilaimmune deficiency (IMD) and Toll pathway components, an AMP gene expression profile inDrosophilacells indicated IMD pathway activation upon rickettsial infection. Accordingly, we assessedR. typhi-mediated flea IMD pathway activationin vivousing small interfering RNA (siRNA)-mediated knockdown. Knockdown ofRelishandImdincreasedR. typhiinfection levels, implicating the IMD pathway as a critical regulator ofR. typhiburden inC. felis. These data suggest that targeting the IMD pathway could minimize the spread ofR. typhi, and potentially other human pathogens, vectored by fleas.

scholarly journals Relationship between the Presence of Bartonella Species and Bacterial Loads in Cats and Cat Fleas (Ctenocephalides felis) under Natural Conditions

2015 ◽  
Vol 81 (16) ◽  
pp. 5613-5621 ◽  
Author(s):  
Ricardo Gutiérrez ◽  
Yaarit Nachum-Biala ◽  
Shimon Harrus
Keyword(s):  
Bartonella Henselae ◽  
Ctenocephalides Felis ◽  
Infection Status ◽  
Natural Conditions ◽  
High Resolution Melt ◽  
Content Type ◽  
Real Time Quantitative Pcr ◽  
Stray Cats ◽  
Cat Fleas ◽  
Host Infection

ABSTRACTCats are considered the main reservoir of three zoonoticBartonellaspecies:Bartonella henselae,Bartonellaclarridgeiae, andBartonellakoehlerae. Cat fleas (Ctenocephalides felis) have been experimentally demonstrated to be a competent vector ofB. henselaeand have been proposed as the potential vector of the two otherBartonellaspecies. Previous studies have reported a lack of association between theBartonellaspecies infection status (infected or uninfected) and/or bacteremia levels of cats and the infection status of the fleas they host. Nevertheless, to date, no study has compared the quantitative distributions of these bacteria in both cats and their fleas under natural conditions. Thus, the present study explored these relationships by identifying and quantifying the differentBartonellaspecies in both cats and their fleas. Therefore, EDTA-blood samples and fleas collected from stray cats were screened forBartonellabacteria. Bacterial loads were quantified by high-resolution melt real-time quantitative PCR assays. The results indicated a moderate correlation between theBartonellabacterial loads in the cats and their fleas when both were infected with the sameBartonellaspecies. Moreover, a positive effect of the host infection status on theBartonellabacterial loads of the fleas was observed. Conversely, the cat bacterial loads were not affected by the infection status of their fleas. Our results suggest that theBartonellabacterial loads of fleas are positively affected by the presence of the bacteria in their feline host, probably by multiple acquisitions/accumulation and/or multiplication events.

scholarly journals In VitroAntibacterial Activity of NB-003 against Propionibacterium acnes

2011 ◽  
Vol 55 (9) ◽  
pp. 4211-4217 ◽  
Author(s):  
J. Pannu ◽  
A. McCarthy ◽  
A. Martin ◽  
T. Hamouda ◽  
S. Ciotti ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Propionibacterium Acnes ◽  
Resistant Mutant ◽  
Microtiter Plate ◽  
Content Type ◽  
Oil In Water ◽  
Complete Disruption ◽  
Kinetics Of ◽  
Gel Formulations

ABSTRACTNB-003 and NB-003 gel formulations are oil-in-water nanoemulsions designed for use in bacterial infections.In vitrosusceptibility ofPropionibacterium acnesto NB-003 formulations and comparator drugs was evaluated. Both NB-003 formulations were bactericidal against allP. acnesisolates, including those that were erythromycin, clindamycin, and/or tetracycline resistant. In the absence of sebum, the MIC90s/minimum bactericidal concentrations (MBC90s) for NB-003, NB-003 gel, salicylic acid (SA), and benzoyl peroxide (BPO) were 0.5/2.0, 1.0/2.0, 1,000/2,000, and 50/200 μg/ml, respectively. In the presence of 50% sebum, the MIC90s/MBC90s of NB003 and BPOs increased to 128/1,024 and 400/1,600 μg/ml, respectively. The MIC90s/MBC90s of SA were not significantly impacted by the presence of sebum. A reduction in the MBC90s for NB-003 and BPO was observed when 2% SA or 0.5% BPO was integrated into the formulation, resulting in MIC90s/MBC90s of 128/256 μg/ml for NB003 and 214/428 μg/ml for BPO. The addition of EDTA enhanced thein vitroefficacy of 0.5% NB-003 in the presence or absence of 25% sebum. The addition of 5 mM EDTA to each well of the microtiter plate resulted in a >16- and >256-fold decrease in MIC90and MBC90, yielding a more potent MIC90/MBC90of ≤1/<1 μg/ml. The kinetics of bactericidal activity of NB-003 againstP. acneswere compared to those of a commercially available product of BPO. Electron micrographs ofP. acnestreated with NB-003 showed complete disruption of bacteria. Assessment of spontaneous resistance ofP. acnesrevealed no stably resistant mutant strains.

Blood Consumption by the Cat Flea, Ctenocephalides felis (Siphonaptera: Pulicidae)

1991 ◽  
Vol 28 (3) ◽  
pp. 394-400 ◽  
Author(s):  
Michael W. Dryden ◽  
Sayed M. Gaafar
Keyword(s):  
Ctenocephalides Felis ◽  
Cat Flea

scholarly journals Bactericidal Activity, Absence of Serum Effect, and Time-Kill Kinetics of Ceftazidime-Avibactam against β-Lactamase-Producing Enterobacteriaceae and Pseudomonas aeruginosa

2014 ◽  
Vol 58 (9) ◽  
pp. 5297-5305 ◽  
Author(s):  
Tiffany R. Keepers ◽  
Marcela Gomez ◽  
Chris Celeri ◽  
Wright W. Nichols ◽  
Kevin M. Krause
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Human Serum ◽  
Bactericidal Activity ◽  
Minimum Bactericidal Concentration ◽  
Wild Type ◽  
Content Type ◽  
Positive Isolate ◽  
New Treatment ◽  
Time Kill ◽  
Kinetics Of

ABSTRACTAvibactam, a non-β-lactam β-lactamase inhibitor with activity against extended-spectrum β-lactamases (ESBLs), KPC, AmpC, and some OXA enzymes, extends the antibacterial activity of ceftazidime against most ceftazidime-resistant organisms producing these enzymes. In this study, the bactericidal activity of ceftazidime-avibactam against 18Pseudomonas aeruginosaisolates and 15Enterobacteriaceaeisolates, including wild-type isolates and ESBL, KPC, and/or AmpC producers, was evaluated. Ceftazidime-avibactam MICs (0.016 to 32 μg/ml) were lower than those for ceftazidime alone (0.06 to ≥256 μg/ml) against all isolates except for 2P. aeruginosaisolates (1blaVIM-positive isolate and 1blaOXA-23-positive isolate). The minimum bactericidal concentration/MIC ratios of ceftazidime-avibactam were ≤4 for all isolates, indicating bactericidal activity. Human serum and human serum albumin had a minimal effect on ceftazidime-avibactam MICs. Ceftazidime-avibactam time-kill kinetics were evaluated at low MIC multiples and showed time-dependent reductions in the number of CFU/ml from 0 to 6 h for all strains tested. A ≥3-log10decrease in the number of CFU/ml was observed at 6 h for allEnterobacteriaceae, and a 2-log10reduction in the number of CFU/ml was observed at 6 h for 3 of the 6P. aeruginosaisolates. Regrowth was noted at 24 h for some of the isolates tested in time-kill assays. These data demonstrate the potent bactericidal activity of ceftazidime-avibactam and support the continued clinical development of ceftazidime-avibactam as a new treatment option for infections caused byEnterobacteriaceaeandP. aeruginosa, including isolates resistant to ceftazidime by mechanisms dependent on avibactam-sensitive β-lactamases.

scholarly journals Factors Influencing the Microbial Composition of Metalworking Fluids and Potential Implications for Machine Operator's Lung

2011 ◽  
Vol 78 (1) ◽  
pp. 34-41 ◽  
Author(s):  
Jean-Benjamin Murat ◽  
Frédéric Grenouillet ◽  
Gabriel Reboux ◽  
Emmanuelle Penven ◽  
Adam Batchili ◽  
...  
Keyword(s):  
Metal Cutting ◽  
Hypersensitivity Pneumonitis ◽  
Environmental Parameters ◽  
Metalworking Fluids ◽  
Microbial Composition ◽  
Gram Positive ◽  
Gram Negative ◽  
Content Type ◽  
Kinetics Of

ABSTRACTHypersensitivity pneumonitis, also known as “machine operator's lung” (MOL), has been related to microorganisms growing in metalworking fluids (MWFs), especiallyMycobacterium immunogenum. We aimed to (i) describe the microbiological contamination of MWFs and (ii) look for chemical, physical, and environmental parameters associated with variations in microbiological profiles. We microbiologically analyzed 180 MWF samples from nonautomotive plants (e.g., screw-machining or metal-cutting plants) in the Franche-Comté region in eastern France and 165 samples from three French automotive plants in which cases of MOL had been proven. Our results revealed two types of microbial biomes: the first was from the nonautomotive industry, showed predominantly Gram-negative rods (GNR), and was associated with a low risk of MOL, and the second came from the automotive industry that was affected by cases of MOL and showed predominantly Gram-positive rods (GPR). Traces ofM. immunogenumwere sporadically detected in the first type, while it was highly prevalent in the automotive sector, with up to 38% of samples testing positive. The use of chromium, nickel, or iron was associated with growth of Gram-negative rods; conversely, growth of Gram-positive rods was associated with the absence of these metals. Synthetic MWFs were more frequently sterile than emulsions. Vegetable oil-based emulsions were associated with GNR, while mineral ones were associated with GPR. Our results suggest that metal types and the nature of MWF play a part in MWF contamination, and this work shall be followed by furtherin vitrosimulation experiments on the kinetics of microbial populations, focusing on the phenomena of inhibition and synergy.

scholarly journals Testing Sorption Properties of Halloysite by Means of the Laser Interferometry Method

2015 ◽  
Vol 37 (1) ◽  
pp. 43-47
Author(s):  
Sławomir Wąsik ◽  
Michał Arabski ◽  
Karolina Maciejec ◽  
Grażyna Suchanek ◽  
Anna Świercz
Keyword(s):  
Concentration Field ◽  
Laser Interferometry ◽  
Membrane System ◽  
Absorption Capacity ◽  
Sorption Properties ◽  
Concentration Profiles ◽  
Adsorbed Substance ◽  
Interferometry Method ◽  
Set Up ◽  
Kinetics Of

The objective of the present study has been to test the laser interferometry method in terms of its usability for investigating sorption properties of minerals. This method was used to test the absorption capacity of halloysite with reference to glucose, which is often found in industrial wastewater and whose excess can disturb the environmental eco-balance. The sorption capacity of halloysite was thus determined indirectly, basing on the comparison of concentration profiles as well as time characteristics of glucose quantities released from the control solution and from the solution incubated with a halloysite adsorbent. An analysis of glucose diffusion was conducted in a two-chamber membrane system. On the basis of the obtained concentration profiles, the evolution of the concentration field was determined; so were the removal efficiency (%) and the amount of glucose adsorbed at equilibrium (qe, mg/g). The obtained results confirm good sorption properties of halloysite with respect to the investigated substance as well as usability of the method for this kind of investigations. The presented tests suggest that the measurement set-up can be optimised in such as way that visual rendering and testing the kinetics of the adsorbed substance direct release from the studied material become possible.

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