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Firdose A, Maeda T, Sukri MAM, Yasin NHM, Sabturani N, Aqma WS. Antibacterial mechanism of Pseudomonas aeruginosa UKMP14T rhamnolipids against multidrug resistant Acinetobacter baumannii. Microb Pathog 2024; 193:106743. [PMID: 38879138 DOI: 10.1016/j.micpath.2024.106743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 06/06/2024] [Accepted: 06/11/2024] [Indexed: 06/21/2024]
Abstract
Rhamnolipids, a major category of glycolipid biosurfactant, have recently gained enormous attention in medical field because of their relevance as effective antibacterial agents against a wide variety of pathogenic bacteria. Our previous studies have shown that rhamnolipids from an environmental isolate of Pseudomonas aeruginosa UKMP14T possess antibacterial, anti-adhesive and anti-biofilm activity against multidrug-resistant ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter sp.) pathogens. However, the mechanism of their antibacterial action remains unclear. Thus, this study aimed to elucidate the mechanism of the antibacterial action of P. aeruginosa UKMP14T rhamnolipids by studying the changes in cells of one of the ESKAPE pathogens, Acinetobacter baumannii, which is the most difficult strain to kill. Results revealed that rhamnolipid treatment rendered A. baumannii cells more hydrophobic as evaluated through contact angle measurements. It also induced the release of cellular proteins measuring 510 μg/mL at a rhamnolipid concentration of 1000 μg/mL. In addition, rhamnolipids were found to be bactericidal in their action as they could permeate the inner membranes, leading to a leak-out of nucleotides. More than 50 % of the cells were found to be killed upon 1000 μg/mL rhamnolipid treatment as observed through fluorescence microscopy. Other cellular changes such as irregular shape and size, membrane perturbations, clumping, shrinkage and physical damage were clearly visible in SEM, FESEM and laser micrographs. Furthermore, rhamnolipid treatment inhibited the levels of acyl-homoserine lactones (AHLs) in A. baumannii, which are vital for their biofilm formation and virulence. The obtained results indicate that P. aeruginosa UKMP14T rhamnolipids target outer and inner bacterial membranes through permeation, including physical damage to the cells, leading to cell leakage. Furthermore, AHL inhibition appears to be the mechanism behind their anti-biofilm action. All these observations can be correlated to rhamnolipids' antibacterial effect against A. baumannii.
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Affiliation(s)
- Ayesha Firdose
- Department of Biological Sciences & Biotechnology, Faculty of Science & Technology, Universiti Kebangsaan Malaysia, 46300 Bangi, Selangor, Malaysia.
| | - Toshinari Maeda
- Department of Biological Functions Engineering, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu-ku, Kitakyushu 808-0196, Japan
| | - Mohd Asif Mohd Sukri
- Department of Biological Sciences & Biotechnology, Faculty of Science & Technology, Universiti Kebangsaan Malaysia, 46300 Bangi, Selangor, Malaysia
| | - Nazlina Haiza Mohd Yasin
- Department of Biological Sciences & Biotechnology, Faculty of Science & Technology, Universiti Kebangsaan Malaysia, 46300 Bangi, Selangor, Malaysia
| | - Noramiza Sabturani
- Department of Biological Sciences & Biotechnology, Faculty of Science & Technology, Universiti Kebangsaan Malaysia, 46300 Bangi, Selangor, Malaysia
| | - Wan Syaidatul Aqma
- Department of Biological Sciences & Biotechnology, Faculty of Science & Technology, Universiti Kebangsaan Malaysia, 46300 Bangi, Selangor, Malaysia.
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Abstract
Infections are the leading cause of mortality in burn patients who survive their initial resuscitation. Burn injury leads to immunosuppression and a dysregulated inflammatory response which can have a prolonged impact. Early surgical excision along with support of the multidisciplinary burn team has improved mortality in burn patients. The authors review diagnostic and therapeutic challenges as well as strategies for management of burn related infections.
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Carcione D, Siracusa C, Sulejmani A, Migliavacca R, Mercato A, Piazza A, Principe L, Clementi N, Mancini N, Leoni V, Intra J. In Vitro Antimicrobial Activity of the Siderophore Cephalosporin Cefiderocol against Acinetobacter baumannii Strains Recovered from Clinical Samples. Antibiotics (Basel) 2021; 10:antibiotics10111309. [PMID: 34827247 PMCID: PMC8614976 DOI: 10.3390/antibiotics10111309] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 10/22/2021] [Accepted: 10/23/2021] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Cefiderocol is a siderophore cephalosporin that exhibits antimicrobial activity against most multi-drug resistant Gram-negative bacteria, including Enterobacterales, Pseudomonas aeruginosa, Acinetobacter baumannii, and Stenotrophomonas maltophilia. METHODS A total of 20 multidrug-resistant A. baumannii strains were isolated from 2020 to 2021, molecularly characterized and tested to assess the in vitro antibacterial activity of cefiderocol. Thirteen strains were carbapenem-hydrolysing oxacillinase OXA-23-like producers, while seven were non-OXA-23-like producers. Minimum inhibitory concentrations (MICs) were determined by broth microdilution, considered as the gold standard method. Disk diffusion test was also carried out using iron-depleted CAMHB plates for cefiderocol. RESULTS Cefiderocol MICs ranged from 0.5 to 1 mg/L for OXA-23-like non-producing A. baumannii strains and from 0.25 to >32 mg/L for OXA-23-like producers, using the broth microdilution method. Cefiderocol MIC90 was 8 mg/L. Diameter of inhibition zone of cefiderocol ranged from 18 to 25 mm for OXA-23-like non-producers and from 15 to 36 mm for OXA-23-like producers, using the diffusion disk method. A large variability and a low reproducibility were observed during the determination of diameter inhibition zone. Molecular characterization showed that all isolates presented the ISAba1 genetic element upstream the blaOXA-51. Among OXA-23-like non-producers, four were blaOXA-58 positive and two were negative for all the resistance determinants analyzed. CONCLUSIONS Cefiderocol showed in vitro antimicrobial activity against both carbapenem-susceptible and non-susceptible A. baumannii strains, although some OXA-23-like producers were resistant. Further clinical studies are needed to consolidate the role of cefiderocol as an antibiotic against MDR A. baumannii.
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Affiliation(s)
- Davide Carcione
- Department of Laboratory Medicine, University of Milano-Bicocca, Azienda Socio Sanitaria Territoriale Brianza ASST-Brianza, Desio Hospital, via Mazzini 1, 20833 Desio, Italy; (D.C.); (C.S.); (A.S.); (V.L.)
| | - Claudia Siracusa
- Department of Laboratory Medicine, University of Milano-Bicocca, Azienda Socio Sanitaria Territoriale Brianza ASST-Brianza, Desio Hospital, via Mazzini 1, 20833 Desio, Italy; (D.C.); (C.S.); (A.S.); (V.L.)
| | - Adela Sulejmani
- Department of Laboratory Medicine, University of Milano-Bicocca, Azienda Socio Sanitaria Territoriale Brianza ASST-Brianza, Desio Hospital, via Mazzini 1, 20833 Desio, Italy; (D.C.); (C.S.); (A.S.); (V.L.)
| | - Roberta Migliavacca
- Unit of Microbiology and Clinical Microbiology, Department of Clinical-Surgical, Diagnostic and Pediatric Sciences, University of Pavia, 27100 Pavia, Italy; (R.M.); (A.M.); (A.P.)
| | - Alessandra Mercato
- Unit of Microbiology and Clinical Microbiology, Department of Clinical-Surgical, Diagnostic and Pediatric Sciences, University of Pavia, 27100 Pavia, Italy; (R.M.); (A.M.); (A.P.)
| | - Aurora Piazza
- Unit of Microbiology and Clinical Microbiology, Department of Clinical-Surgical, Diagnostic and Pediatric Sciences, University of Pavia, 27100 Pavia, Italy; (R.M.); (A.M.); (A.P.)
| | - Luigi Principe
- Clinical Pathology and Microbiology Unit, S. Giovanni di Dio Hospital, 88900 Crotone, Italy
- Correspondence:
| | - Nicola Clementi
- Laboratorio di Microbiologia e Virologia, Università Vita-Salute San Raffaele, 20132 Milan, Italy; (N.C.); (N.M.)
- IRCCS Ospedale San Raffaele, 20132 Milan, Italy
| | - Nicasio Mancini
- Laboratorio di Microbiologia e Virologia, Università Vita-Salute San Raffaele, 20132 Milan, Italy; (N.C.); (N.M.)
- IRCCS Ospedale San Raffaele, 20132 Milan, Italy
| | - Valerio Leoni
- Department of Laboratory Medicine, University of Milano-Bicocca, Azienda Socio Sanitaria Territoriale Brianza ASST-Brianza, Desio Hospital, via Mazzini 1, 20833 Desio, Italy; (D.C.); (C.S.); (A.S.); (V.L.)
| | - Jari Intra
- Clinical Chemistry Laboratory, University of Milano-Bicocca, Azienda Socio Sanitaria Territoriale di Monza ASST-Monza, San Gerardo Hospital, via Pergolesi 33, 20900 Monza, Italy;
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Lynch C, Mahida N, Oppenheim B, Gray J. Looking back on 2019 and commemorating 40 years of HIS and JHI. J Hosp Infect 2020; 104:1-3. [DOI: 10.1016/j.jhin.2019.11.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 11/28/2019] [Indexed: 10/25/2022]
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