Epinecidin-1 Has Immunomodulatory Effects, Facilitating Its Therapeutic Use in a Mouse Model of Pseudomonas aeruginosa Sepsis

ABSTRACTAntimicrobial peptides (AMPs) are garnering attention as possible alternatives to antibiotics. Here, we describe the antimicrobial properties of epinecidin-1 against a multidrug-resistant clinical isolate ofP. aeruginosa(P. aeruginosaR) and aP. aeruginosastrain from ATCC (P. aeruginosaATCC 19660)in vivo. The MICs of epinecidin-1 againstP. aeruginosaR andP. aeruginosaATCC 19660 were determined and compared with those of imipenem. Epinecidin-1 was found to be highly effective at combating peritonitis infection caused byP. aeruginosaR orP. aeruginosaATCC 19660 in mouse models, without inducing adverse behavioral effects or liver or kidney toxicity. Taken together, our results indicate that epinecidin-1 enhances the rate of survival of mice infected with the bacterial pathogenP. aeruginosathrough both antimicrobial and immunomodulatory effects.

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Synergistic Efficacy of Aedes aegypti Antimicrobial Peptide Cecropin A2 and Tetracycline against Pseudomonas aeruginosa

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00686-17 ◽

2017 ◽

Vol 61 (7) ◽

Cited By ~ 31

Author(s):

Zhaojun Zheng ◽

Nagendran Tharmalingam ◽

Qingzhong Liu ◽

Elamparithi Jayamani ◽

Wooseong Kim ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Aedes Aegypti ◽

Mammalian Cells ◽

Galleria Mellonella ◽

Multidrug Resistant ◽

Resistant Bacteria ◽

Synergistic Activity ◽

Content Type

ABSTRACT The increasing prevalence of antibiotic resistance has created an urgent need for alternative drugs with new mechanisms of action. Antimicrobial peptides (AMPs) are promising candidates that could address the spread of multidrug-resistant bacteria, either alone or in combination with conventional antibiotics. We studied the antimicrobial efficacy and bactericidal mechanism of cecropin A2, a 36-residue α-helical cationic peptide derived from Aedes aegypti cecropin A, focusing on the common pathogen Pseudomonas aeruginosa. The peptide showed little hemolytic activity and toxicity toward mammalian cells, and the MICs against most clinical P. aeruginosa isolates were 32 to 64 μg/ml, and its MICs versus other Gram-negative bacteria were 2 to 32 μg/ml. Importantly, cecropin A2 demonstrated synergistic activity against P. aeruginosa when combined with tetracycline, reducing the MICs of both agents by 8-fold. The combination was also effective in vivo in the P. aeruginosa/Galleria mellonella model (P < 0.001). We found that cecropin A2 bound to P. aeruginosa lipopolysaccharides, permeabilized the membrane, and interacted with the bacterial genomic DNA, thus facilitating the translocation of tetracycline into the cytoplasm. In summary, the combination of cecropin A2 and tetracycline demonstrated synergistic antibacterial activity against P. aeruginosa in vitro and in vivo, offering an alternative approach for the treatment of P. aeruginosa infections.

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Multicenter Evaluation of Ceftazidime-Avibactam and Ceftolozane-Tazobactam Inhibitory Activity against Meropenem-Nonsusceptible Pseudomonas aeruginosa from Blood, Respiratory Tract, and Wounds

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00875-17 ◽

2017 ◽

Vol 61 (10) ◽

Cited By ~ 32

Author(s):

Mordechai Grupper ◽

Christina Sutherland ◽

David P. Nicolau

Keyword(s):

Pseudomonas Aeruginosa ◽

Inhibitory Activity ◽

Clinical Utility ◽

Multidrug Resistant ◽

Resistance Mechanisms ◽

Broth Microdilution ◽

Content Type ◽

Carbapenem Resistant

ABSTRACT The recent escalation of occurrences of carbapenem-resistant Pseudomonas aeruginosa has been recognized globally and threatens to erode the widespread clinical utility of the carbapenem class of compounds for this prevalent health care-associated pathogen. Here, we compared the in vitro inhibitory activity of ceftazidime-avibactam and ceftolozane-tazobactam against 290 meropenem-nonsusceptible Pseudomonas aeruginosa nonduplicate clinical isolates from 34 U.S. hospitals using reference broth microdilution methods. Ceftazidime-avibactam and ceftolozane-tazobactam were active, with ceftolozane-tazobactam having significantly higher inhibitory activity than ceftazidime-avibactam. The heightened inhibitory activity of ceftolozane-tazobactam was sustained when the site of origin (respiratory, blood, or wound) and nonsusceptibility to other β-lactam antimicrobials was considered. An extensive genotypic search for enzymatically driven β-lactam resistance mechanisms revealed the exclusive presence of the VIM metallo-β-lactamase among only 4% of the subset of isolates nonsusceptible to ceftazidime-avibactam, ceftolozane-tazobactam, or both. These findings suggest an important role for both ceftazidime-avibactam and ceftolozane-tazobactam against carbapenem-nonsusceptible Pseudomonas aeruginosa. Further in vitro and in vivo studies are needed to better define the clinical utility of these novel therapies against the increasingly prevalent threat of multidrug-resistant Pseudomonas aeruginosa.

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Severe Acinetobacter baumannii Sepsis Is Associated with Elevation of Pentraxin 3

Infection and Immunity ◽

10.1128/iai.01958-14 ◽

2014 ◽

Vol 82 (9) ◽

pp. 3910-3918 ◽

Cited By ~ 14

Author(s):

Patrick M. Ketter ◽

M. Neal Guentzel ◽

Beverly Schaffer ◽

Maryanne Herzig ◽

Xiaowu Wu ◽

...

Keyword(s):

Acinetobacter Baumannii ◽

Lethal Dose ◽

Antimicrobial Properties ◽

Bloodstream Infections ◽

Multidrug Resistant ◽

Mouse Serum ◽

Myeloperoxidase Activity ◽

Content Type

ABSTRACTMultidrug-resistantAcinetobacter baumanniiis among the most prevalent bacterial pathogens associated with trauma-related wound and bloodstream infections. Although septic shock and disseminated intravascular coagulation have been reported following fulminantA. baumanniisepsis, little is known about the protective host immune response to this pathogen. In this study, we examined the role of PTX3, a soluble pattern recognition receptor with reported antimicrobial properties and stored within neutrophil granules. PTX3 production by murine J774a.1 macrophages was assessed following challenge withA. baumanniistrains ATCC 19606 and clinical isolates (CI) 77, 78, 79, 80, and 86. Interestingly, only CI strains 79, 80, and 86 induced PTX3 synthesis in murine J774a.1 macrophages, with greatest production observed following CI 79 and 86 challenge. Subsequently, C57BL/6 mice were challenged intraperitoneally with CI 77 and 79 to assess the role of PTX3in vivo.A. baumanniistrain CI 79 exhibited significantly (P< 0.0005) increased mortality, with an approximate 50% lethal dose (LD50) of 105CFU, while an equivalent dose of CI 77 exhibited no mortality. Plasma leukocyte chemokines (KC, MCP-1, and RANTES) and myeloperoxidase activity were also significantly elevated following challenge with CI 79, indicating neutrophil recruitment/activation associated with significant elevation in serum PTX3 levels. Furthermore, 10-fold-greater PTX3 levels were observed in mouse serum 12 h postchallenge, comparing CI 79 to CI 77 (1,561 ng/ml versus 145 ng/ml), with concomitant severe pathology (liver and spleen) and coagulopathy. Together, these results suggest that elevation of PTX3 is associated with fulminant disease duringA. baumanniisepsis.

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Inhibition of Pseudomonas aeruginosa by Peptide-Conjugated Phosphorodiamidate Morpholino Oligomers

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01938-16 ◽

2017 ◽

Vol 61 (4) ◽

Cited By ~ 16

Author(s):

James J. Howard ◽

Carolyn R. Sturge ◽

Dina A. Moustafa ◽

Seth M. Daly ◽

Kimberly R. Marshall-Batty ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Antibiotic Resistance ◽

Polymyxin B ◽

Multidrug Resistant ◽

Essential Genes ◽

Content Type ◽

Novel Approach ◽

Phosphorodiamidate Morpholino Oligomers

ABSTRACT Pseudomonas aeruginosa is a highly virulent, multidrug-resistant pathogen that causes significant morbidity and mortality in hospitalized patients and is particularly devastating in patients with cystic fibrosis. Increasing antibiotic resistance coupled with decreasing numbers of antibiotics in the developmental pipeline demands novel antibacterial approaches. Here, we tested peptide-conjugated phosphorodiamidate morpholino oligomers (PPMOs), which inhibit translation of complementary mRNA from specific, essential genes in P. aeruginosa. PPMOs targeted to acpP, lpxC, and rpsJ, inhibited P. aeruginosa growth in many clinical strains and activity of PPMOs could be enhanced 2- to 8-fold by the addition of polymyxin B nonapeptide at subinhibitory concentrations. The PPMO targeting acpP was also effective at preventing P. aeruginosa PAO1 biofilm formation and at reducing existing biofilms. Importantly, treatment with various combinations of a PPMO and a traditional antibiotic demonstrated synergistic growth inhibition, the most effective of which was the PPMO targeting rpsJ with tobramycin. Furthermore, treatment of P. aeruginosa PA103-infected mice with PPMOs targeting acpP, lpxC, or rpsJ significantly reduced the bacterial burden in the lungs at 24 h by almost 3 logs. Altogether, this study demonstrates that PPMOs targeting the essential genes acpP, lpxC, or rpsJ in P. aeruginosa are highly effective at inhibiting growth in vitro and in vivo. These data suggest that PPMOs alone or in combination with antibiotics represent a novel approach to addressing the problems associated with rapidly increasing antibiotic resistance in P. aeruginosa.

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A 2.5-Year Within-Patient Evolution of Pseudomonas aeruginosa Isolates with In Vivo Acquisition of Ceftolozane-Tazobactam and Ceftazidime-Avibactam Resistance upon Treatment

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01637-19 ◽

2019 ◽

Vol 63 (12) ◽

Cited By ~ 9

Author(s):

Thibaud Boulant ◽

Agnès B. Jousset ◽

Rémy A. Bonnin ◽

Aurélie Barrail-Tran ◽

Adrien Borgel ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Acquired Resistance ◽

Multidrug Resistant ◽

Sequencing Analysis ◽

Nucleotide Polymorphisms ◽

Related Sequence ◽

Content Type ◽

Partial Restoration

ABSTRACT Ceftolozane-tazobactam is considered to be a last-resort treatment for infections caused by multidrug-resistant (MDR) Pseudomonas aeruginosa. Although resistance to this antimicrobial has been described in vitro, the development of resistance in vivo has rarely been reported. Here, we describe the evolution of resistance to ceftolozane-tazobactam of P. aeruginosa isolates recovered from the same patient during recurrent infections over 2.5 years. Antimicrobial susceptibility testing results showed that 24 of the 27 P. aeruginosa isolates recovered from blood (n = 18), wound (n = 2), pulmonary (n = 1), bile (n = 2), and stool (n = 4) samples from the same patient were susceptible to ceftolozane-tazobactam and ceftazidime-avibactam but resistant to ceftazidime, piperacillin-tazobactam, imipenem, and meropenem. Three clinical isolates acquired resistance to ceftolozane-tazobactam and ceftazidime-avibactam along with a partial restoration of piperacillin-tazobactam and carbapenem susceptibilities. Whole-genome sequencing analysis reveals that all isolates were clonally related (sequence type 111 [ST-111]), with a median of 24.9 single nucleotide polymorphisms (SNPs) (range, 8 to 48 SNPs). The ceftolozane-tazobactam and ceftazidime-avibactam resistance was likely linked to the same G183D substitution in the chromosome-encoded cephalosporinase. Our results suggest that resistance to ceftolozane-tazobactam in P. aeruginosa might occur in vivo upon treatment through an amino acid substitution in the intrinsic AmpC leading to ceftolozane-tazobactam and ceftazidime-avibactam resistance, accompanied by resensitization to piperacillin-tazobactam and carbapenems.

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In Vitro and In Vivo Activities of β-Lactams in Combination with the Novel β-Lactam Enhancers Zidebactam and WCK 5153 against Multidrug-Resistant Metallo-β-Lactamase-Producing Klebsiella pneumoniae

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00128-19 ◽

2019 ◽

Vol 63 (5) ◽

Cited By ~ 16

Author(s):

Bartolome Moya ◽

Isabel M. Barcelo ◽

Gabriel Cabot ◽

Gabriel Torrens ◽

Snehal Palwe ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Klebsiella Pneumoniae ◽

Molecular Targets ◽

Multidrug Resistant ◽

The Novel ◽

Penicillin Binding Protein ◽

Content Type ◽

Time Kill

ABSTRACT Zidebactam and WCK 5153 are novel bicyclo-acyl hydrazide (BCH) agents that have previously been shown to act as β-lactam enhancer (BLE) antibiotics in Pseudomonas aeruginosa and Acinetobacter baumannii. The objectives of this work were to identify the molecular targets of these BCHs in Klebsiella pneumoniae and to investigate their potential BLE activity for cefepime and aztreonam against metallo-β-lactamase (MBL)-producing strains in vitro and in vivo. Penicillin binding protein (PBP) binding profiles were determined by Bocillin FL assay, and 50% inhibitory concentrations (IC50s) were determined using ImageQuant TL software. MICs and kill kinetics for zidebactam, WCK 5153, and cefepime or aztreonam, alone and in combination, were determined against clinical K. pneumoniae isolates producing MBLs VIM-1 or NDM-1 (plus ESBLs and class C β-lactamases) to assess the in vitro enhancer effect of BCH compounds in conjunction with β-lactams. Additionally, murine systemic and thigh infection studies were conducted to evaluate BLE effects in vivo. Zidebactam and WCK 5153 showed specific, high PBP2 affinity in K. pneumoniae. The MICs of BLEs were >64 μg/ml for all MBL-producing strains. Time-kill studies showed that a combination of these BLEs with either cefepime or aztreonam provided 1 to >3 log10 kill against MBL-producing K. pneumoniae strains. Furthermore, the bactericidal synergy observed for these BLE–β-lactam combinations translated well into in vivo efficacy even in the absence of MBL inhibition by BLEs, a characteristic feature of the β-lactam enhancer mechanism of action. Zidebactam and WCK 5153 are potent PBP2 inhibitors and display in vitro and in vivo BLE effects against multidrug-resistant (MDR) K. pneumoniae clinical isolates producing MBLs.

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Impact of Type III Secretion Effectors and of Phenoxyacetamide Inhibitors of Type III Secretion on Abscess Formation in a Mouse Model of Pseudomonas aeruginosa Infection

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01202-17 ◽

2017 ◽

Vol 61 (11) ◽

Cited By ~ 22

Author(s):

Bryan J. Berube ◽

Katherine R. Murphy ◽

Matthew C. Torhan ◽

Nicholas O. Bowlin ◽

John D. Williams ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Mouse Model ◽

Type Iii Secretion ◽

Abscess Formation ◽

Host Cells ◽

Block Type ◽

Content Type ◽

Type Iii

ABSTRACT Pseudomonas aeruginosa is a leading cause of intra-abdominal infections, wound infections, and community-acquired folliculitis, each of which may involve macro- or microabscess formation. The rising incidence of multidrug resistance among P. aeruginosa isolates has increased both the economic burden and the morbidity and mortality associated with P. aeruginosa disease and necessitates a search for novel therapeutics. Previous work from our group detailed novel phenoxyacetamide inhibitors that block type III secretion and injection into host cells in vitro. In this study, we used a mouse model of P. aeruginosa abscess formation to test the in vivo efficacy of these compounds against the P. aeruginosa type III secretion system (T3SS). Bacteria used the T3SS to intoxicate infiltrating neutrophils to establish abscesses. Despite this antagonism, sufficient numbers of functioning neutrophils remained for proper containment of the abscesses, as neutrophil depletion resulted in an increased abscess size, the formation of dermonecrotic lesions on the skin, and the dissemination of P. aeruginosa to internal organs. Consistent with the specificity of the T3SS-neutrophil interaction, P. aeruginosa bacteria lacking a functional T3SS were fully capable of causing abscesses in a neutropenic host. Phenoxyacetamide inhibitors attenuated abscess formation and aided in the immune clearance of the bacteria. Finally, a P. aeruginosa strain resistant to the phenoxyacetamide compound was fully capable of causing abscess formation even in the presence of the T3SS inhibitors. Together, our results further define the role of type III secretion in murine abscess formation and demonstrate the in vivo efficacy of phenoxyacetamide inhibitors in P. aeruginosa infection.

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Genome Sequence of Clinical Strain Pseudomonas aeruginosa NRD619

Microbiology Resource Announcements ◽

10.1128/mra.01013-20 ◽

2020 ◽

Vol 9 (44) ◽

Author(s):

Laura Sisk-Hackworth ◽

Andrew Sue ◽

Saima Aslam ◽

Dwayne Roach

Keyword(s):

Pseudomonas Aeruginosa ◽

Genome Sequence ◽

Bacterial Pathogen ◽

Multidrug Resistant ◽

Sinus Tract ◽

Left Ventricular ◽

Clinical Strain ◽

Ventricular Assist ◽

Content Type ◽

Public Health Burden

ABSTRACT Here, we report the complete genome sequence of the multidrug-resistant (MDR) strain Pseudomonas aeruginosa NRD619, assembled via long- and short-read hybrid assembly. P. aeruginosa is a Gram-negative bacterial pathogen that is a significant public health burden. NRD619 was isolated from a left ventricular assist device (LVAD) draining sinus tract.

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In Vivo Efficacy of WCK 5222 (Cefepime-Zidebactam) against Multidrug-Resistant Pseudomonas aeruginosa in the Neutropenic Murine Thigh Infection Model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00233-19 ◽

2019 ◽

Vol 63 (7) ◽

Cited By ~ 12

Author(s):

Marguerite L. Monogue ◽

Jennifer Tabor-Rennie ◽

Kamilia Abdelraouf ◽

David P. Nicolau

Keyword(s):

Pseudomonas Aeruginosa ◽

Multidrug Resistant ◽

Infection Model ◽

In Vivo Efficacy ◽

Content Type

ABSTRACT We describe the in vivo efficacy of human-simulated WCK 5222 (cefepime-zidebactam) exposure against multidrug-resistant Pseudomonas aeruginosa (meropenem MICs 8 to >256 μg/ml) in a neutropenic murine thigh infection model. WCK 5222 MICs ranged from 4 to 32 μg/ml. Substantial in vivo WCK 5222 activity was observed against all isolates, further enhancing the efficacy of zidebactam alone in 11/16 isolates (WCK 5222 mean reduction, –1.62 ± 0.58 log10 CFU/thigh), and a lack of activity was observed with cefepime monotherapy.

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Exogenous Alginate Protects Staphylococcus aureus from Killing by Pseudomonas aeruginosa

Journal of Bacteriology ◽

10.1128/jb.00559-19 ◽

2019 ◽

Vol 202 (8) ◽

Cited By ~ 2

Author(s):

Courtney E. Price ◽

Dustin G. Brown ◽

Dominique H. Limoli ◽

Vanessa V. Phelan ◽

George A. O’Toole

Keyword(s):

Staphylococcus Aureus ◽

Pseudomonas Aeruginosa ◽

Physical Space ◽

Late Time ◽

Protective Effects ◽

Content Type ◽

Alginate Production ◽

The Impact

ABSTRACT Cystic fibrosis (CF) patients chronically infected with both Pseudomonas aeruginosa and Staphylococcus aureus have worse health outcomes than patients who are monoinfected with either P. aeruginosa or S. aureus. We showed previously that mucoid strains of P. aeruginosa can coexist with S. aureus in vitro due to the transcriptional downregulation of several toxic exoproducts typically produced by P. aeruginosa, including siderophores, rhamnolipids, and HQNO (2-heptyl-4-hydroxyquinoline N-oxide). Here, we demonstrate that exogenous alginate protects S. aureus from P. aeruginosa in both planktonic and biofilm coculture models under a variety of nutritional conditions. S. aureus protection in the presence of exogenous alginate is due to the transcriptional downregulation of pvdA, a gene required for the production of the iron-scavenging siderophore pyoverdine as well as the downregulation of the PQS (Pseudomonas quinolone signal) (2-heptyl-3,4-dihydroxyquinoline) quorum sensing system. The impact of exogenous alginate is independent of endogenous alginate production. We further demonstrate that coculture of mucoid P. aeruginosa with nonmucoid P. aeruginosa strains can mitigate the killing of S. aureus by the nonmucoid strain of P. aeruginosa, indicating that the mechanism that we describe here may function in vivo in the context of mixed infections. Finally, we investigated a panel of mucoid clinical isolates that retain the ability to kill S. aureus at late time points and show that each strain has a unique expression profile, indicating that mucoid isolates can overcome the S. aureus-protective effects of mucoidy in a strain-specific manner. IMPORTANCE CF patients are chronically infected by polymicrobial communities. The two dominant bacterial pathogens that infect the lungs of CF patients are P. aeruginosa and S. aureus, with ∼30% of patients coinfected by both species. Such coinfected individuals have worse outcomes than monoinfected patients, and both species persist within the same physical space. A variety of host and environmental factors have been demonstrated to promote P. aeruginosa-S. aureus coexistence, despite evidence that P. aeruginosa kills S. aureus when these organisms are cocultured in vitro. Thus, a better understanding of P. aeruginosa-S. aureus interactions, particularly mechanisms by which these microorganisms are able to coexist in proximal physical space, will lead to better-informed treatments for chronic polymicrobial infections.

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