Mutations in pmrB Confer Cross-Resistance between the LptD Inhibitor POL7080 and Colistin in Pseudomonas aeruginosa

ABSTRACT Pseudomonas aeruginosa is a major bacterial pathogen associated with a rising prevalence of antibiotic resistance. We evaluated the resistance mechanisms of P. aeruginosa against POL7080, a species-specific, first-in-class antibiotic in clinical trials that targets the lipopolysaccharide transport protein LptD. We isolated a series of POL7080-resistant strains with mutations in the two-component sensor gene pmrB. Transcriptomic and confocal microscopy studies support a resistance mechanism shared with colistin, involving lipopolysaccharide modifications that mitigate antibiotic cell surface binding.

Download Full-text

Mutations inpmrBconfer cross-resistance to the LptD inhibitor POL7080 and colistin inPseudomonas aeruginosa

10.1101/571224 ◽

2019 ◽

Author(s):

Keith P Romano ◽

Thulasi Warrier ◽

Bradley E Poulsen ◽

Phuong H Nguyen ◽

Alexander R Loftis ◽

...

Keyword(s):

Lipid A ◽

Bacterial Pathogen ◽

Resistance Mechanisms ◽

Cross Resistance ◽

Resistance Mutations ◽

Surface Binding ◽

Phase 3 ◽

Cell Surface Binding ◽

Genome Wide ◽

Species Specific

Pseudomonas aeruginosais a major bacterial pathogen for which there is rising antibiotic resistance. We evaluated the resistance mechanisms ofP. aeruginosaagainst POL7080, a species-specific, first-in-class antibiotic in phase 3 clinical trials targeting the lipopolysaccharide transport protein LptD. We found resistance mutations in the two-component regulatorpmrB. Genome-wide transcriptomics and confocal microscopy studies together suggest that POL7080 is vulnerable to the same resistance mechanisms described previously for polymyxins, including colistin, that involve lipid A modifications to mitigate antibiotic cell surface binding.

Download Full-text

Art-175 Is a Highly Efficient Antibacterial against Multidrug-Resistant Strains and Persisters of Pseudomonas aeruginosa

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02668-14 ◽

2014 ◽

Vol 58 (7) ◽

pp. 3774-3784 ◽

Cited By ~ 90

Author(s):

Yves Briers ◽

Maarten Walmagh ◽

Barbara Grymonprez ◽

Manfred Biebl ◽

Jean-Paul Pirnay ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Outer Membrane ◽

Time Lapse ◽

Bactericidal Effect ◽

Multidrug Resistant ◽

Resistance Mechanisms ◽

Cross Resistance ◽

Chronic Infections ◽

Content Type ◽

Resistant Strains

ABSTRACTArtilysins constitute a novel class of efficient enzyme-based antibacterials. Specifically, they covalently combine a bacteriophage-encoded endolysin, which degrades the peptidoglycan, with a targeting peptide that transports the endolysin through the outer membrane of Gram-negative bacteria. Art-085, as well as Art-175, its optimized homolog with increased thermostability, are each composed of the sheep myeloid 29-amino acid (SMAP-29) peptide fused to the KZ144 endolysin. In contrast to KZ144, Art-085 and Art-175 pass the outer membrane and killPseudomonas aeruginosa, including multidrug-resistant strains, in a rapid and efficient (∼5 log units) manner. Time-lapse microscopy confirms that Art-175 punctures the peptidoglycan layer within 1 min, inducing a bulging membrane and complete lysis. Art-175 is highly refractory to resistance development by naturally occurring mutations. In addition, the resistance mechanisms against 21 therapeutically used antibiotics do not show cross-resistance to Art-175. Since Art-175 does not require an active metabolism for its activity, it has a superior bactericidal effect againstP. aeruginosapersisters (up to >4 log units compared to that of the untreated controls). In summary, Art-175 is a novel antibacterial that is well suited for a broad range of applications in hygiene and veterinary and human medicine, with a unique potential to target persister-driven chronic infections.

Download Full-text

Challenging Antimicrobial Susceptibility and Evolution of Resistance (OXA-681) during Treatment of a Long-Term Nosocomial Infection Caused by a Pseudomonas aeruginosa ST175 Clone

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01110-19 ◽

2019 ◽

Vol 63 (10) ◽

Cited By ~ 7

Author(s):

Jorge Arca-Suárez ◽

Pablo Fraile-Ribot ◽

Juan Carlos Vázquez-Ucha ◽

Gabriel Cabot ◽

Marta Martínez-Guitián ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Nosocomial Infection ◽

Resistance Mechanisms ◽

Cross Resistance ◽

The Novel ◽

Content Type ◽

Narrow Spectrum ◽

Extended Spectrum

ABSTRACT Selection of extended-spectrum mutations in narrow-spectrum oxacillinases (e.g., OXA-2 and OXA-10) is an emerging mechanism for development of in vivo resistance to ceftolozane-tazobactam and ceftazidime-avibactam in Pseudomonas aeruginosa. Detection of these challenging enzymes therefore seems essential to prevent clinical failure, but the complex phenotypic plasticity exhibited by this species may often lead to their underestimation. The underlying resistance mechanisms of two sequence type 175 (ST175) P. aeruginosa isolates showing multidrug-resistant phenotypes and recovered at early and late stages of a long-term nosocomial infection were evaluated. Whole-genome sequencing (WGS) was used to investigate resistance genomics, whereas molecular and biochemical methods were used for characterization of a novel extended-spectrum OXA-2 variant selected during therapy. The metallo-β-lactamase blaVIM-20 and the narrow-spectrum oxacillinase blaOXA-2 were present in both isolates, although they differed by an inactivating mutation in the mexB subunit, present only in the early isolate, and in a mutation in the blaOXA-2 β-lactamase, present only in the final isolate. The new OXA-2 variant, designated OXA-681, conferred elevated MICs of the novel cephalosporin–β-lactamase inhibitor combinations in a PAO1 background. Compared to OXA-2, kinetic parameters of the OXA-681 enzyme revealed a substantial increase in the hydrolysis of cephalosporins, including ceftolozane. We describe the emergence of the novel variant OXA-681 during treatment of a nosocomial infection caused by a Pseudomonas aeruginosa ST175 high-risk clone. The ability of OXA-681 to confer cross-resistance to ceftolozane-tazobactam and ceftazidime-avibactam together with the complex antimicrobial resistance profiles exhibited by the clinical strains harboring this new enzyme argue for maintaining active surveillance on emerging broad-spectrum resistance in P. aeruginosa.

Download Full-text

No Decrease in Susceptibility to NVC-422 in Multiple-Passage Studies with Methicillin-Resistant Staphylococcus aureus, S. aureus, Pseudomonas aeruginosa, and Escherichia coli

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.05985-11 ◽

2012 ◽

Vol 56 (5) ◽

pp. 2753-2755 ◽

Cited By ~ 13

Author(s):

Louisa D'Lima ◽

Lisa Friedman ◽

Lu Wang ◽

Ping Xu ◽

Mark Anderson ◽

...

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Pseudomonas Aeruginosa ◽

Fusidic Acid ◽

Methicillin Resistant Staphylococcus Aureus ◽

Cross Resistance ◽

Methicillin Resistant ◽

Content Type ◽

E Coli ◽

Resistant Strains

ABSTRACTTwenty-five serial passages ofEscherichia coli,Pseudomonas aeruginosa, andStaphylococcus aureusand 50 passages of methicillin-resistantStaphylococcus aureusresulted in no significant increase in NVC-422 MICs, while ciprofloxacin MICs increased 256-fold forE. coliand 32-fold forP. aeruginosaandS. aureus. Mupirocin, fusidic acid, and retapamulin MICs for MRSA increased 64-, 256-, and 16-fold, respectively. No cross-resistance to NVC-422 was observed with mupirocin-, fusidic acid-, and retapamulin-resistant strains.

Download Full-text

Ceftolozane/Tazobactam Resistance and Mechanisms in Carbapenem-Nonsusceptible Pseudomonas aeruginosa

mSphere ◽

10.1128/msphere.01026-20 ◽

2021 ◽

Vol 6 (1) ◽

Author(s):

Jocelyn Qi-Min Teo ◽

Jie Chong Lim ◽

Cheng Yee Tang ◽

Shannon Jing-Yi Lee ◽

Si Hui Tan ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Molecular Epidemiology ◽

Whole Genome Sequencing ◽

Genome Sequencing ◽

Antimicrobial Agents ◽

Resistance Mechanisms ◽

Cross Resistance ◽

Whole Genome ◽

Genotypic Resistance ◽

Content Type

ABSTRACT This study established the in vitro activity of ceftolozane/tazobactam (C/T) and its genotypic resistance mechanisms by whole-genome sequencing (WGS) in 195 carbapenem-nonsusceptible Pseudomonas aeruginosa (CNSPA) clinical isolates recovered from Singapore between 2009 and 2020. C/T susceptibility rates were low, at 37.9%. Cross-resistance to ceftazidime/avibactam was observed, although susceptibility to the agent was slightly higher, at 41.0%. Whole-genome sequencing revealed that C/T resistance was largely mediated by the presence of horizontally acquired β-lactamases, especially metallo-β-lactamases. These were primarily disseminated in well-recognized high-risk clones belonging to sequence types (ST) 235, 308, and 179. C/T resistance was also observed in several non-carbapenemase-producing isolates, in which resistance was likely mediated by β-lactamases and, to a smaller extent, mutations in AmpC-related genes. There was no obvious mechanism of resistance observed in five isolates. The high C/T resistance highlights the limited utility of the agent as an empirical agent in our setting. Knowledge of local molecular epidemiology is crucial in determining the potential of therapy with novel agents. IMPORTANCE Pseudomonas aeruginosa infection is one of the most difficult health care-associated infections to treat due to the ability of the organism to acquire a multitude of resistance mechanisms and express the multidrug resistance phenotype. Ceftolozane/tazobactam (C/T), a novel β-lactam/β-lactamase inhibitor combination, addresses an unmet medical need in patients with these multidrug-resistant P. aeruginosa infections. Our findings demonstrate geographical variation in C/T susceptibility owing to the distinct local molecular epidemiology. This study adds on to the growing knowledge of C/T resistance, particularly mutational resistance, and will aid in the design of future β-lactams and β-lactamase inhibitors. WGS proved to be a useful tool to understand the P. aeruginosa resistome and its contribution to emerging resistance in novel antimicrobial agents.

Download Full-text

Draft Genome Sequences of Two Pseudomonas aeruginosa Multidrug-Resistant Clinical Isolates, PAL0.1 and PAL1.1

Microbiology Resource Announcements ◽

10.1128/mra.00940-18 ◽

2018 ◽

Vol 7 (17) ◽

Author(s):

Teddy Grandjean ◽

Rémi Le Guern ◽

Claire Duployez ◽

Karine Faure ◽

Eric Kipnis ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Draft Genome ◽

Acquired Resistance ◽

Multidrug Resistant ◽

Resistance Mechanisms ◽

Blood Cultures ◽

Ventilator Associated Pneumonia ◽

Genome Sequences ◽

Content Type ◽

Resistant Strains

Pseudomonas aeruginosa infections are challenging due to intrinsic and acquired resistance mechanisms. We report here the draft genome sequences of two multidrug-resistant strains—PAL0.1, isolated from the airways of an intensive care unit (ICU) patient with ventilator-associated pneumonia, and PAL1.1, isolated from blood cultures of an ICU patient with sepsis.

Download Full-text

cyp51A-Based Mechanisms of Aspergillus fumigatus Azole Drug Resistance Present in Clinical Samples from Germany

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00167-13 ◽

2013 ◽

Vol 57 (8) ◽

pp. 3513-3517 ◽

Cited By ~ 87

Author(s):

Oliver Bader ◽

Michael Weig ◽

Utz Reichard ◽

Raimond Lugert ◽

Martin Kuhns ◽

...

Keyword(s):

Aspergillus Fumigatus ◽

Resistance Mechanism ◽

Cross Resistance ◽

Clinical Samples ◽

Steady Increase ◽

Clinical Test ◽

Content Type ◽

Visible Growth ◽

Resistant Strains ◽

High Level

ABSTRACTSince the mid-1990s, a steady increase in the occurrence of itraconazole-resistantAspergillus fumigatusisolates has been observed in clinical contexts, leading to therapeutic failure in the treatment of aspergillosis. This increase has been predominantly linked to a single allele of thecyp51Agene, termed TR/L98H, which is thought to have arisen through the use of agricultural azoles. Here, we investigated the current epidemiology of triazole-resistantA. fumigatusand underlyingcyp51Amutations in clinical samples in Germany. From a total of 527 samples, 17 (3.2%) showed elevated MIC0values (the lowest concentrations with no visible growth) for at least one of the three substances (itraconazole, voriconazole, and posaconazole) tested. The highest prevalence of resistant isolates was observed in cystic fibrosis patients (5.2%). Among resistant isolates, the TR/L98H mutation incyp51Awas the most prevalent, but isolates with the G54W and M220I substitutions and the novel F219C substitution were also found. The isolate with the G54W substitution was highly resistant to both itraconazole and posaconazole, while all others showed high-level resistance only to itraconazole. For the remaining six isolates, no mutations incyp51Awere found, indicating the presence of other mechanisms. With the exception of the strains carrying the F219C and M220I substitutions, many itraconazole-resistant strains also showed cross-resistance to voriconazole and posaconazole with moderately increased MIC0values. In conclusion, the prevalence of azole-resistantA. fumigatusin our clinical test set is lower than that previously reported for other countries. Although the TR/L98H mutation frequently occurs among triazole-resistant strains in Germany, it is not the only resistance mechanism present.

Download Full-text

Activity of Ceftazidime-Avibactam against Fluoroquinolone-Resistant Enterobacteriaceae and Pseudomonas aeruginosa

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.05136-14 ◽

2015 ◽

Vol 59 (6) ◽

pp. 3059-3065 ◽

Cited By ~ 14

Author(s):

C. Pitart ◽

F. Marco ◽

T. A. Keating ◽

W. W. Nichols ◽

J. Vila

Keyword(s):

Pseudomonas Aeruginosa ◽

Resistant Mutant ◽

Fluoroquinolone Resistance ◽

Cross Resistance ◽

Content Type ◽

E Coli ◽

Microdilution Method ◽

Broth Microdilution Method ◽

The Impact

ABSTRACTCeftazidime-avibactam and comparator antibiotics were tested by the broth microdilution method against 200Enterobacteriaceaeand 25Pseudomonas aeruginosastrains resistant to fluoroquinolones (including strains with the extended-spectrum β-lactamase [ESBL] phenotype and ceftazidime-resistant strains) collected from our institution. The MICs and mechanisms of resistance to fluoroquinolone were also studied. Ninety-nine percent of fluoroquinolone-resistantEnterobacteriaceaestrains were inhibited at a ceftazidime-avibactam MIC of ≤4 mg/liter (using the susceptible CLSI breakpoint for ceftazidime alone as a reference). Ceftazidime-avibactam was very active against ESBLEscherichia coli(MIC90of 0.25 mg/liter), ESBLKlebsiella pneumoniae(MIC90of 0.5 mg/liter), ceftazidime-resistant AmpC-producing species (MIC90of 1 mg/liter), non-ESBLE. coli(MIC90of ≤0.125 mg/liter), non-ESBLK. pneumoniae(MIC90of 0.25 mg/liter), and ceftazidime-nonresistant AmpC-producing species (MIC90of ≤0.5 mg/liter). Ninety-six percent of fluoroquinolone-resistantP. aeruginosastrains were inhibited at a ceftazidime-avibactam MIC of ≤8 mg/liter (using the susceptible CLSI breakpoint for ceftazidime alone as a reference), with a MIC90of 8 mg/liter. Additionally, fluoroquinolone-resistant mutants from each species tested were obtainedin vitrofrom two strains, one susceptible to ceftazidime and the other a β-lactamase producer with a high MIC against ceftazidime but susceptible to ceftazidime-avibactam. Thereby, the impact of fluoroquinolone resistance on the activity of ceftazidime-avibactam could be assessed. The MIC90values of ceftazidime-avibactam for the fluoroquinolone-resistant mutant strains ofEnterobacteriaceaeandP. aeruginosawere ≤4 mg/liter and ≤8 mg/liter, respectively. We conclude that the presence of fluoroquinolone resistance does not affectEnterobacteriaceaeandP. aeruginosasusceptibility to ceftazidime-avibactam; that is, there is no cross-resistance.

Download Full-text

Lead Optimization of Dehydroemetine for Repositioned Use in Malaria

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01444-19 ◽

2020 ◽

Vol 64 (4) ◽

Author(s):

Priyanka Panwar ◽

Kepa K. Burusco ◽

Muna Abubaker ◽

Holly Matthews ◽

Andrey Gutnov ◽

...

Keyword(s):

De Novo ◽

Antimalarial Activity ◽

Drug Repositioning ◽

Multidrug Resistant ◽

Cross Resistance ◽

Synthetic Analogue ◽

80S Ribosome ◽

Content Type ◽

Resistant Strains

ABSTRACT Drug repositioning offers an effective alternative to de novo drug design to tackle the urgent need for novel antimalarial treatments. The antiamoebic compound emetine dihydrochloride has been identified as a potent in vitro inhibitor of the multidrug-resistant strain K1 of Plasmodium falciparum (50% inhibitory concentration [IC50], 47 nM ± 2.1 nM [mean ± standard deviation]). Dehydroemetine, a synthetic analogue of emetine dihydrochloride, has been reported to have less-cardiotoxic effects than emetine. The structures of two diastereomers of dehydroemetine were modeled on the published emetine binding site on the cryo-electron microscopy (cryo-EM) structure with PDB code 3J7A (P. falciparum 80S ribosome in complex with emetine), and it was found that (−)-R,S-dehydroemetine mimicked the bound pose of emetine more closely than did (−)-S,S-dehydroisoemetine. (−)-R,S-dehydroemetine (IC50 71.03 ± 6.1 nM) was also found to be highly potent against the multidrug-resistant K1 strain of P. falciparum compared with (−)-S,S-dehydroisoemetine (IC50, 2.07 ± 0.26 μM), which loses its potency due to the change of configuration at C-1′. In addition to its effect on the asexual erythrocytic stages of P. falciparum, the compound exhibited gametocidal properties with no cross-resistance against any of the multidrug-resistant strains tested. Drug interaction studies showed (−)-R,S-dehydroemetine to have synergistic antimalarial activity with atovaquone and proguanil. Emetine dihydrochloride and (−)-R,S-dehydroemetine failed to show any inhibition of the hERG potassium channel and displayed activity affecting the mitochondrial membrane potential, indicating a possible multimodal mechanism of action.

Download Full-text

Detection of resistance genes from Pseudomonas aeruginosa using immunomagnetic isolation and chemiluminescence

Materials Express ◽

10.1166/mex.2020.1650 ◽

2020 ◽

Vol 10 (3) ◽

pp. 412-418

Author(s):

Fei Xu ◽

Cheng Chen ◽

Xing Li ◽

Bo Zhang

Keyword(s):

Pseudomonas Aeruginosa ◽

Resistance Genes ◽

High Efficiency ◽

Bacterial Pathogen ◽

Resistance Mechanisms ◽

Clinical Samples ◽

Specific Gene ◽

Beta Lactamases ◽

Immunomagnetic Isolation ◽

Encoding Gene

Pseudomonas aeruginosa (P. aeruginosa) is a common opportunistic and nosocomial bacterial pathogen. Various multi-resistance mechanisms present across numerous P. aeruginosa strains counteract conventional antimicrobial therapy, thereby becoming a great challenge. This study aimed to establish the application of immunomagnetic isolation and chemiluminescence to detect the presence of extended spectra of β-lactamases encoding genes: blaTEM and blaVEB; metallo-beta-lactamases encoding gene: blaVIM; aminoglycoside modifying enzymes encoding gene: aac(6)II, ant(3)I; and the specific gene for P. aeruginosa, gyrB. P. aeruginosa was specifically selected using the immunomagnetic nanoparticles (IMNPs) in the six parallel bacterial plates counting, proving that they are reliable. Then, the high efficiency of IMNPs@Probes in targeting the resistance genes of P. aeruginosa was demonstrated using the results of chemiluminescent intensities of blaTEM, blaVEB, blaVIM aac(6)II, ant(3)I, and gyrB (more than 10 times higher than that of the control). Sixty-eight in situ clinical samples were tested for the presence of these resistance genes, and one more blaTEM and three more blaVIM individuals were detected using this method compared to the traditional PCR. Thus, the application of our method in clinical screening is specific, accurate, and reliable, and it could be useful in the administration of appropriate treatment.

Download Full-text