Efficacy assessment of a novel endolysin PlyAZ3aT for the treatment of ceftriaxone-resistant pneumococcal meningitis in an infant rat model.

Valente, Luca G; Le, Ngoc Dung; Pitton, Melissa; Chiffi, Gabriele; Grandgirard, Denis; Jakob, Stephan M; Cameron, David R; Resch, Grégory; Que, Yok-Ai; Leib, Stephen L (2022). Efficacy assessment of a novel endolysin PlyAZ3aT for the treatment of ceftriaxone-resistant pneumococcal meningitis in an infant rat model. PLoS ONE, 17(4), e0266928. Public Library of Science 10.1371/journal.pone.0266928

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BACKGROUND

Treatment failure in pneumococcal meningitis due to antibiotic resistance is an increasing clinical challenge and alternatives to antibiotics warrant investigation. Phage-derived endolysins efficiently kill gram-positive bacteria including multi-drug resistant strains, making them attractive therapeutic candidates. The current study assessed the therapeutic potential of the novel endolysin PlyAZ3aT in an infant rat model of ceftriaxone-resistant pneumococcal meningitis.

METHODS

Efficacy of PlyAZ3aT was assessed in a randomized, blinded and controlled experimental study in infant Wistar rats. Meningitis was induced by intracisternal infection with 5 x 107 CFU/ml of a ceftriaxone-resistant clinical strain of S. pneumoniae, serotype 19A. Seventeen hours post infection (hpi), animals were randomized into 3 treatment groups and received either (i) placebo (phosphate buffered saline [PBS], n = 8), (ii) 50 mg/kg vancomycin (n = 10) or (iii) 400 mg/kg PlyAZ3aT (n = 8) via intraperitoneal injection. Treatments were repeated after 12 h. Survival at 42 hpi was the primary outcome; bacterial loads in cerebrospinal fluid (CSF) and blood were secondary outcomes. Additionally, pharmacokinetics of PlyAZ3aT in serum and CSF was assessed.

RESULTS

PlyAZ3aT did not improve survival compared to PBS, while survival for vancomycin treated animals was 70% which is a significant improvement when compared to PBS or PlyAZ3aT (p<0.05 each). PlyAZ3aT was not able to control the infection, reflected by the inability to reduce bacterial loads in the CSF, whereas Vancomycin sterilized the CSF and within 25 h. Pharmacokinetic studies indicated that PlyAZ3aT did not cross the blood brain barrier (BBB). In support, PlyAZ3aT showed a peak concentration of 785 μg/ml in serum 2 h after intraperitoneal injection but could not be detected in CSF.

CONCLUSION

In experimental pneumococcal meningitis, PlyAZ3aT failed to cure the infection due to an inability to reach the CSF. Optimization of the galenic formulation e.g. using liposomes might enable crossing of the BBB and improve treatment efficacy.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Service Sector > Institute for Infectious Diseases
04 Faculty of Medicine > Department of Intensive Care, Emergency Medicine and Anaesthesiology (DINA) > Clinic of Intensive Care
04 Faculty of Medicine > Service Sector > Institute for Infectious Diseases > Research

Graduate School:

Graduate School for Cellular and Biomedical Sciences (GCB)

UniBE Contributor:

Valente, Luca Gabriele, Le, Ngoc Dung, Pitton, Melissa Phung-Kieu, Chiffi, Gabriele, Grandgirard, Denis, Jakob, Stephan, Cameron, David Robert, Que, Yok-Ai, Leib, Stephen

Subjects:

500 Science > 570 Life sciences; biology
600 Technology > 610 Medicine & health

ISSN:

1932-6203

Publisher:

Public Library of Science

Language:

English

Submitter:

Pubmed Import

Date Deposited:

27 Apr 2022 11:00

Last Modified:

05 Dec 2022 16:19

Publisher DOI:

10.1371/journal.pone.0266928

PubMed ID:

35472061

BORIS DOI:

10.48350/169546

URI:

https://boris.unibe.ch/id/eprint/169546

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