Role of Rifampin against Propionibacterium acnes BiofilmIn Vitroand in an Experimental Foreign-Body Infection Model

ABSTRACTPropionibacterium acnesis an important cause of orthopedic-implant-associated infections, for which the optimal treatment has not yet been determined. We investigated the activity of rifampin, alone and in combination, against planktonic and biofilmP. acnes in vitroand in a foreign-body infection model. The MIC and the minimal bactericidal concentration (MBC) were 0.007 and 4 μg/ml for rifampin, 1 and 4 μg/ml for daptomycin, 1 and 8 μg/ml for vancomycin, 1 and 2 μg/ml for levofloxacin, 0.03 and 16 μg/ml for penicillin G, 0.125 and 512 μg/ml for clindamycin, and 0.25 and 32 μg/ml for ceftriaxone. TheP. acnesminimal biofilm eradication concentration (MBEC) was 16 μg/ml for rifampin; 32 μg/ml for penicillin G; 64 μg/ml for daptomycin and ceftriaxone; and ≥128 μg/ml for levofloxacin, vancomycin, and clindamycin. In the animal model, implants were infected by injection of 109CFUP. acnesin cages. Antimicrobial activity onP. acneswas investigated in the cage fluid (planktonic form) and on explanted cages (biofilm form). The cure rates were 4% for daptomycin, 17% for vancomycin, 0% for levofloxacin, and 36% for rifampin. Rifampin cured 63% of the infected cages in combination with daptomycin, 46% with vancomycin, and 25% with levofloxacin. While all tested antimicrobials showed good activity against planktonicP. acnes, for eradication of biofilms, rifampin was needed. In combination with rifampin, daptomycin showed higher cure rates than with vancomycin in this foreign-body infection model.

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Activities of Fosfomycin, Tigecycline, Colistin, and Gentamicin against Extended-Spectrum-β-Lactamase-Producing Escherichia coli in a Foreign-Body Infection Model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01718-12 ◽

2013 ◽

Vol 57 (3) ◽

pp. 1421-1427 ◽

Cited By ~ 66

Author(s):

Stéphane Corvec ◽

Ulrika Furustrand Tafin ◽

Bertrand Betrisey ◽

Olivier Borens ◽

Andrej Trampuz

Keyword(s):

Escherichia Coli ◽

Foreign Body ◽

Single Agent ◽

Infection Model ◽

Minimal Bactericidal Concentration ◽

Synergistic Activity ◽

Cure Rate ◽

Gram Negative ◽

Content Type

ABSTRACTLimited antimicrobial agents are available for the treatment of implant-associated infections caused by fluoroquinolone-resistant Gram-negative bacilli. We compared the activities of fosfomycin, tigecycline, colistin, and gentamicin (alone and in combination) against a CTX-M15-producing strain ofEscherichia coli(Bj HDE-1)in vitroand in a foreign-body infection model. The MIC and the minimal bactericidal concentration in logarithmic phase (MBClog) and stationary phase (MBCstat) were 0.12, 0.12, and 8 μg/ml for fosfomycin, 0.25, 32, and 32 μg/ml for tigecycline, 0.25, 0.5, and 2 μg/ml for colistin, and 2, 8, and 16 μg/ml for gentamicin, respectively. In time-kill studies, colistin showed concentration-dependent activity, but regrowth occurred after 24 h. Fosfomycin demonstrated rapid bactericidal activity at the MIC, and no regrowth occurred. Synergistic activity between fosfomycin and colistinin vitrowas observed, with no detectable bacterial counts after 6 h. In animal studies, fosfomycin reduced planktonic counts by 4 log10CFU/ml, whereas in combination with colistin, tigecycline, or gentamicin, it reduced counts by >6 log10CFU/ml. Fosfomycin was the only single agent which was able to eradicateE. colibiofilms (cure rate, 17% of implanted, infected cages). In combination, colistin plus tigecycline (50%) and fosfomycin plus gentamicin (42%) cured significantly more infected cages than colistin plus gentamicin (33%) or fosfomycin plus tigecycline (25%) (P< 0.05). The combination of fosfomycin plus colistin showed the highest cure rate (67%), which was significantly better than that of fosfomycin alone (P< 0.05). In conclusion, the combination of fosfomycin plus colistin is a promising treatment option for implant-associated infections caused by fluoroquinolone-resistant Gram-negative bacilli.

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Gentamicin Improves the Activities of Daptomycin and Vancomycin against Enterococcus faecalis In Vitro and in an Experimental Foreign-Body Infection Model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00141-11 ◽

2011 ◽

Vol 55 (10) ◽

pp. 4821-4827 ◽

Cited By ~ 34

Author(s):

Ulrika Furustrand Tafin ◽

Ivana Majic ◽

Cyrine Zalila Belkhodja ◽

Bertrand Betrisey ◽

Stéphane Corvec ◽

...

Keyword(s):

Foreign Body ◽

Enterococcus Faecalis ◽

Early Stage ◽

Infection Model ◽

Minimal Bactericidal Concentration ◽

Logarithmic Phase ◽

Cure Rate ◽

Percutaneous Injection ◽

Content Type

ABSTRACTFor enterococcal implant-associated infections, the optimal treatment regimen has not been defined. We investigated the activity of daptomycin, vancomycin, and gentamicin (and their combinations) againstEnterococcus faecalis in vitroand in a foreign-body infection model. Antimicrobial activity was investigated by time-kill and growth-related heat production studies (microcalorimetry) as well as with a guinea pig model using subcutaneously implanted cages. Infection was established by percutaneous injection ofE. faecalisin the cage. Antibiotic treatment for 4 days was started 3 h after infection. Cages were removed 5 days after end of treatment to determine the cure rate. The MIC, the minimal bactericidal concentration (MBC) in the logarithmic phase, and the MBC in the stationary phase were 1.25, 5, and >20 μg/ml for daptomycin, 1, >64, and >64 μg/ml for vancomycin, and 16, 32, and 4 μg/ml for gentamicin, respectively.In vitro, gentamicin at subinhibitory concentrations improved the activity againstE. faecaliswhen combined with daptomycin or vancomycin in the logarithmic and stationary phases. In the animal model, daptomycin cured 25%, vancomycin 17%, and gentamicin 50% of infected cages. In combination with gentamicin, the cure rate for daptomycin increased to 55% and that of vancomycin increased to 33%. In conclusion, daptomycin was more active than vancomycin against adherentE. faecalis, and its activity was further improved by the addition of gentamicin. Despite a short duration of infection (3 h), the cure rates did not exceed 55%, highlighting the difficulty of eradicatingE. faecalisfrom implants already in the early stage of implant-associated infection.

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Activity of the Pore-Forming Virulence Factor Listeriolysin O Is Reversibly Inhibited by Naturally Occurring S-Glutathionylation

Infection and Immunity ◽

10.1128/iai.00959-16 ◽

2017 ◽

Vol 85 (4) ◽

Cited By ~ 15

Author(s):

Jonathan L. Portman ◽

Qiongying Huang ◽

Michelle L. Reniere ◽

Anthony T. Iavarone ◽

Daniel A. Portnoy

Keyword(s):

Protein Function ◽

Inhibitory Effect ◽

Cysteine Residue ◽

Infection Model ◽

Listeriolysin O ◽

Content Type ◽

Pore Forming Proteins

ABSTRACT Cholesterol-dependent cytolysins (CDCs) represent a family of homologous pore-forming proteins secreted by many Gram-positive bacterial pathogens. CDCs mediate membrane binding partly through a conserved C-terminal undecapeptide, which contains a single cysteine residue. While mutational changes to other residues in the undecapeptide typically have severe effects, mutation of the cysteine residue to alanine has minor effects on overall protein function. Thus, the role of this highly conserved reactive cysteine residue remains largely unknown. We report here that the CDC listeriolysin O (LLO), secreted by the facultative intracellular pathogen Listeria monocytogenes, was posttranslationally modified by S-glutathionylation at this conserved cysteine residue and that either endogenously synthesized or exogenously added glutathione was sufficient to form this modification. When recapitulated with purified protein in vitro, this modification completely ablated the activity of LLO, and this inhibitory effect was fully reversible by treatment with reducing agents. A cysteine-to-alanine mutation in LLO rendered the protein completely resistant to inactivation by S-glutathionylation, and a mutant expressing this mutation retained full hemolytic activity. A mutant strain of L. monocytogenes expressing the cysteine-to-alanine variant of LLO was able to infect and replicate within bone marrow-derived macrophages indistinguishably from the wild type in vitro, yet it was attenuated 4- to 6-fold in a competitive murine infection model in vivo. This study suggests that S-glutathionylation may represent a mechanism by which CDC-family proteins are posttranslationally modified and regulated and help explain an evolutionary pressure to retain the highly conserved undecapeptide cysteine.

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Activities of Fosfomycin and Rifampin on Planktonic and Adherent Enterococcus faecalis Strains in an Experimental Foreign-Body Infection Model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02583-12 ◽

2013 ◽

Vol 58 (3) ◽

pp. 1284-1293 ◽

Cited By ~ 34

Author(s):

Alessandra Oliva ◽

Ulrika Furustrand Tafin ◽

Elena Maryka Maiolo ◽

Safaa Jeddari ◽

Bertrand Bétrisey ◽

...

Keyword(s):

Foreign Body ◽

Enterococcus Faecalis ◽

Infection Model ◽

Content Type ◽

Inhibition Of Growth ◽

Planktonic Bacteria ◽

Biofilm Bacteria ◽

Time Kill

ABSTRACTEnterococcal implant-associated infections are difficult to treat because antibiotics generally lack activity against enterococcal biofilms. We investigated fosfomycin, rifampin, and their combinations against planktonic and adherentEnterococcus faecalis(ATCC 19433)in vitroand in a foreign-body infection model. The MIC/MBClogvalues were 32/>512 μg/ml for fosfomycin, 4/>64 μg/ml for rifampin, 1/2 μg/ml for ampicillin, 2/>256 μg/ml for linezolid, 16/32 μg/ml for gentamicin, 1/>64 μg/ml for vancomycin, and 1/5 μg/ml for daptomycin. In time-kill studies, fosfomycin was bactericidal at 8× and 16× MIC, but regrowth of resistant strains occurred after 24 h. With the exception of gentamicin, no complete inhibition of growth-related heat production was observed with other antimicrobials on early (3 h) or mature (24 h) biofilms. In the animal model, fosfomycin alone or in combination with daptomycin reduced planktonic counts by ≈4 log10CFU/ml below the levels before treatment. Fosfomycin cleared planktonic bacteria from 74% of cage fluids (i.e., no growth in aspirated fluid) and eradicated biofilm bacteria from 43% of cages (i.e., no growth from removed cages). In combination with gentamicin, fosfomycin cleared 77% and cured 58% of cages; in combination with vancomycin, fosfomycin cleared 33% and cured 18% of cages; in combination with daptomycin, fosfomycin cleared 75% and cured 17% of cages. Rifampin showed no activity on planktonic or adherentE. faecalis, whereas in combination with daptomycin it cured 17% and with fosfomycin it cured 25% of cages. Emergence of fosfomycin resistance was not observedin vivo. In conclusion, fosfomycin showed activity against planktonic and adherentE. faecalis. Its role against enterococcal biofilms should be further investigated, especially in combination with rifampin and/or daptomycin treatment.

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Successful Development of Bacteriocins into Therapeutic Formulation for Treatment of MRSA Skin Infection in a Murine Model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00829-20 ◽

2020 ◽

Vol 64 (12) ◽

Author(s):

Kirill V. Ovchinnikov ◽

Christian Kranjec ◽

Tage Thorstensen ◽

Harald Carlsen ◽

Dzung B. Diep

Keyword(s):

Skin Infection ◽

Therapeutic Potential ◽

Multidrug Resistant ◽

Penicillin G ◽

Infection Model ◽

Component Mixture ◽

Antibiotic Resistant ◽

Content Type ◽

Infection Treatment

ABSTRACT The emergence of antibiotic-resistant pathogens has caused a serious worldwide problem in infection treatment in recent years. One of the pathogens is methicillin-resistant Staphylococcus aureus (MRSA), which is a major cause of skin and soft tissue infections. Alternative strategies and novel sources of antimicrobials to solve antibiotic resistance problems are urgently needed. In this study, we explored the potential of two broad-spectrum bacteriocins, garvicin KS and micrococcin P1, in skin infection treatments. The two bacteriocins acted synergistically with each other and with penicillin G in killing MRSA in vitro. The MICs of the antimicrobials in the three-component mixture were 40 ng/ml for micrococcin P1 and 2 μg/ml for garvicin KS and penicillin G, which were 62, 16, and at least 1,250 times lower than their MICs when assessed individually. To assess its therapeutic potential further, we challenged the three-component formulation in a murine skin infection model with the multidrug-resistant luciferase-tagged MRSA Xen31, a strain derived from the clinical isolate S. aureus ATCC 33591. Using the tagged-luciferase activity as a reporter for the presence of Xen31 in wounds, we demonstrated that the three-component formulation was efficient in eradicating the pathogen from treated wounds. Furthermore, compared to Fucidin cream, which is an antibiotic commonly used in skin infection treatments, our formulation was also superior in terms of preventing resistance development.

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Acetylcholine Protects against Candida albicans Infection by Inhibiting Biofilm Formation and Promoting Hemocyte Function in a Galleria mellonella Infection Model

Eukaryotic Cell ◽

10.1128/ec.00067-15 ◽

2015 ◽

Vol 14 (8) ◽

pp. 834-844 ◽

Cited By ~ 32

Author(s):

Ranjith Rajendran ◽

Elisa Borghi ◽

Monica Falleni ◽

Federica Perdoni ◽

Delfina Tosi ◽

...

Keyword(s):

Candida Albicans ◽

Biofilm Formation ◽

Galleria Mellonella ◽

Inflammatory Responses ◽

Fungal Infections ◽

Infection Model ◽

Content Type

ABSTRACT Both neuronal acetylcholine and nonneuronal acetylcholine have been demonstrated to modulate inflammatory responses. Studies investigating the role of acetylcholine in the pathogenesis of bacterial infections have revealed contradictory findings with regard to disease outcome. At present, the role of acetylcholine in the pathogenesis of fungal infections is unknown. Therefore, the aim of this study was to determine whether acetylcholine plays a role in fungal biofilm formation and the pathogenesis of Candida albicans infection. The effect of acetylcholine on C. albicans biofilm formation and metabolism in vitro was assessed using a crystal violet assay and phenotypic microarray analysis. Its effect on the outcome of a C. albicans infection, fungal burden, and biofilm formation were investigated in vivo using a Galleria mellonella infection model. In addition, its effect on modulation of host immunity to C. albicans infection was also determined in vivo using hemocyte counts, cytospin analysis, larval histology, lysozyme assays, hemolytic assays, and real-time PCR. Acetylcholine was shown to have the ability to inhibit C. albicans biofilm formation in vitro and in vivo . In addition, acetylcholine protected G. mellonella larvae from C. albicans infection mortality. The in vivo protection occurred through acetylcholine enhancing the function of hemocytes while at the same time inhibiting C. albicans biofilm formation. Furthermore, acetylcholine also inhibited inflammation-induced damage to internal organs. This is the first demonstration of a role for acetylcholine in protection against fungal infections, in addition to being the first report that this molecule can inhibit C. albicans biofilm formation. Therefore, acetylcholine has the capacity to modulate complex host-fungal interactions and plays a role in dictating the pathogenesis of fungal infections.

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Role of Pseudomonas aeruginosa Glutathione Biosynthesis in Lung and Soft Tissue Infection

Infection and Immunity ◽

10.1128/iai.00116-20 ◽

2020 ◽

Vol 88 (6) ◽

Author(s):

Kelly L. Michie ◽

Justine L. Dees ◽

Derek Fleming ◽

Dina A. Moustafa ◽

Joanna B. Goldberg ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Normal Growth ◽

Infection Model ◽

Redox Stress ◽

Burn Wound ◽

Content Type ◽

Acute Pneumonia ◽

Mammalian Infection

ABSTRACT The opportunistic pathogen Pseudomonas aeruginosa is a leading cause of morbidity and mortality worldwide. To survive in both the environment and the host, P. aeruginosa must cope with redox stress. In P. aeruginosa, a primary mechanism for protection from redox stress is the antioxidant glutathione (GSH). GSH is a low-molecular-weight thiol-containing tripeptide (l-γ-glutamyl-l-cysteinyl-glycine) that can function as a reversible reducing agent. GSH plays an important role in P. aeruginosa physiology and is known to modulate several cellular and social processes that are likely important during infection. However, the role of GSH biosynthesis during mammalian infection is not well understood. In this study, we created a P. aeruginosa mutant defective in GSH biosynthesis to examine how loss of GSH biosynthesis affects P. aeruginosa virulence. We found that GSH is critical for normal growth in vitro and provides protection against hydrogen peroxide, bleach, and ciprofloxacin. We also studied the role of P. aeruginosa GSH biosynthesis in four mouse infection models, including the surgical wound, abscess, burn wound, and acute pneumonia models. We discovered that the GSH biosynthesis mutant was slightly less virulent in the acute pneumonia infection model but was equally virulent in the three other models. This work provides new and complementary data regarding the role of GSH in P. aeruginosa during mammalian infection.

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Reversible Daptomycin Tolerance of Adherent Staphylococci in an Implant Infection Model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00172-11 ◽

2011 ◽

Vol 55 (7) ◽

pp. 3510-3516 ◽

Cited By ~ 21

Author(s):

Anne-K. John ◽

Mathias Schmaler ◽

Nina Khanna ◽

Regine Landmann

Keyword(s):

Treatment Failure ◽

Mutant Strain ◽

Calcium Ions ◽

Biofilm Formation ◽

Infection Model ◽

Content Type ◽

Wall Components

ABSTRACTDaptomycin (DAP) is bactericidal against methicillin-resistantStaphylococcus aureus(MRSA)in vitro, but it failed to eradicate MRSA in an experimental model of implant-associated infection. We therefore investigated various factors which could explain treatment failure by evaluating DAP activity, including the role of different cell wall components, adherence, biofilm, and calcium ions (Ca2+)in vitroandin vivo. In the tissue cage infection model, DAP was active only prophylactically and against low inocula. To identify the mechanisms of treatment failure, thein vitroactivity of DAP against planktonic and adherent growingS. aureusandS. epidermidismutants, differing in their capacity of biofilm formation and adherence, was determined. For planktonic staphylococci, the MIC was 0.625 μg/ml. For adherent staphylococci, DAP reduced biofilms at 30 μg/ml. However, it did not kill adherent bacteria up to 500 μg/ml, independent of biofilm biosynthesis (theicamutant strain), nuclease (thenuc1/nuc2mutant strain), LPXTG-anchored adhesin (thesrtAmutant strain), autolysin (theatlmutant strain), or alanyl-LTA (thedltAmutant strain). Resistance of adherent staphylococci was not due to mutations of adherent bacteria, since staphylococci became DAP susceptible after detachment. Phenotypic tolerance was not explained by inactivation of DAP or inability of initial Ca2+-DAP complex formation. However, the addition of up to 100 mg/liter (2.5 mmol/liter) Ca2+gradually improved bactericidal activity toward adherent staphylococciin vitroand increased the prevention rate in the cage model from 40% to 60%. In summary, adherent staphylococci are resistant to DAP killing unless Ca2+is supplemented to physiologic concentrations.

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Activity of Electrical Current in Experimental Propionibacterium acnes Foreign-Body Osteomyelitis

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01863-16 ◽

2016 ◽

Vol 61 (2) ◽

Cited By ~ 5

Author(s):

Suzannah M. Schmidt-Malan ◽

Cassandra L. Brinkman ◽

Kerryl E. Greenwood-Quaintance ◽

Melissa J. Karau ◽

Jayawant N. Mandrekar ◽

...

Keyword(s):

Foreign Body ◽

Propionibacterium Acnes ◽

Electrical Current ◽

Medullary Cavity ◽

Rat Femur ◽

Control Group ◽

Content Type ◽

Treatment Groups ◽

Direct Electrical Current

ABSTRACT Foreign-body-associated infections are often difficult to treat, given that the associated microorganisms are in a biofilm state. Previously, we showed that a low-amperage direct electrical current (DC) reduces Propionibacterium acnes biofilms formed on implant-associated materials in vitro. In this study, low-amperage DC was compared to ceftriaxone treatment or no treatment in a novel rat femur model of foreign-body osteomyelitis. A platinum implant seeded with a P. acnes biofilm (107 CFU/cm2) and 109 CFU of planktonic P. acnes was placed in the femoral medullary cavity. One week later, rats were assigned to one of three treatment groups: no treatment, ceftriaxone treatment, or 200-μA-DC treatment. After 2 weeks of treatment, there were fewer bacteria in the bones of the ceftriaxone group (3.06 log10 CFU/g of bone [P = 0.0209]) and the 200-μA-DC group (0.5 log10 CFU/g [P = 0.0015]) than in those of the control group (6.58 log10 CFU/g). The DC-exposed animals exhibited fewer bacteria than the ceftriaxone-treated animals (P = 0.0330). There were fewer bacteria on the implanted wires in the groups treated with ceftriaxone (0.1 log10 CFU/cm2) or a 200-μA DC (0.1 log10 CFU/cm2) than in the control group (2.53 log10 CFU/cm2 [P, 0.0003 for both comparisons]). Low-amperage DC may be useful for treating, or aiding in the treatment of, foreign-body infections caused by P. acnes.

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In VitroAntibacterial Activity of NB-003 against Propionibacterium acnes

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00561-11 ◽

2011 ◽

Vol 55 (9) ◽

pp. 4211-4217 ◽

Cited By ~ 23

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.

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