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Khong E, Oh JJ, Jimenez JM, Liu R, Dunham S, Monsibais A, Rhoads A, Ghatbale P, Garcia A, Cobián Güemes AG, Blanc AN, Chiu M, Kuo P, Proost M, Kline A, Aslam S, Schooley RT, Whiteson K, Fraley SI, Pride DT. A simple solid media assay for detection of synergy between bacteriophages and antibiotics. Microbiol Spectr 2024:e0322123. [PMID: 38526142 DOI: 10.1128/spectrum.03221-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 02/24/2024] [Indexed: 03/26/2024] Open
Abstract
The emergence of antibiotic-resistant bacteria (ARB) has necessitated the development of alternative therapies to deal with this global threat. Bacteriophages (viruses that target bacteria) that kill ARB are one such alternative. Although phages have been used clinically for decades with inconsistent results, a number of recent advances in phage selection, propagation, and purification have enabled a reevaluation of their utility in contemporary clinical medicine. In most phage therapy cases, phages are administered in combination with antibiotics to ensure that patients receive the standard-of-care treatment. Some phages may work cooperatively with antibiotics to eradicate ARB, as often determined using non-standardized broth assays. We sought to develop a solid media-based assay to assess cooperativity between antibiotics and phages to offer a standardized platform for such testing. We modeled the interactions that occur between antibiotics and phages on solid medium to measure additive, antagonistic, and synergistic interactions. We then tested the method using different bacterial isolates and identified a number of isolates where synergistic interactions were identified. These interactions were not dependent on the specific organism, phage family, or antibiotic used. A priori susceptibility to the antibiotic or the specific phage were not requirements to observe synergistic interactions. Our data also confirm the potential for the restoration of vancomycin to treat vancomycin-resistant Enterococcus (VRE) when used in combination with phages. Solid media assays for the detection of cooperative interactions between antibiotics and phages can be an accessible technique adopted by clinical laboratories to evaluate antibiotic and phage choices in phage therapy.IMPORTANCEBacteriophages have become an important alternative treatment for individuals with life-threatening antibiotic-resistant bacteria (ARB) infections. Because antibiotics represent the standard-of-care for treatment of ARB, antibiotics and phages often are delivered together without evidence that they work cooperatively. Testing for cooperativity can be difficult due to the equipment necessary and a lack of standardized means for performing the testing in liquid medium. We developed an assay using solid medium to identify interactions between antibiotics and phages for gram-positive and gram-negative bacteria. We modeled the interactions between antibiotics and phages on solid medium, and then tested multiple replicates of vancomycin-resistant Enterococcus (VRE) and Stenotrophomonas in the assay. For each organism, we identified synergy between different phage and antibiotic combinations. The development of this solid media assay for assessing synergy between phages and antibiotics will better inform the use of these combinations in the treatment of ARB infections.
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Affiliation(s)
- Ethan Khong
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Joseph J Oh
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Julian M Jimenez
- Department of Bioengineering, University of California San Diego, La Jolla, California, USA
| | - Roland Liu
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Sage Dunham
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, California, USA
| | - Alisha Monsibais
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, California, USA
| | - Alison Rhoads
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Pooja Ghatbale
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Andrew Garcia
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | | | - Alisha N Blanc
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Megan Chiu
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Peiting Kuo
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Marissa Proost
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Ahnika Kline
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Saima Aslam
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Robert T Schooley
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Katrine Whiteson
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, California, USA
| | - Stephanie I Fraley
- Department of Bioengineering, University of California San Diego, La Jolla, California, USA
| | - David T Pride
- Department of Pathology, University of California San Diego, La Jolla, California, USA
- Department of Medicine, University of California San Diego, La Jolla, California, USA
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Cobián Güemes AG, Ghatbale P, Blanc AN, Morgan CJ, Garcia A, Leonard J, Huang L, Kovalick G, Proost M, Chiu M, Kuo P, Oh J, Karthikeyan S, Knight R, Pogliano J, Schooley RT, Pride DT. Jumbo phages are active against extensively drug-resistant eyedrop-associated Pseudomonas aeruginosa infections. Antimicrob Agents Chemother 2023; 67:e0065423. [PMID: 37931230 PMCID: PMC10720484 DOI: 10.1128/aac.00654-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 09/08/2023] [Indexed: 11/08/2023] Open
Abstract
Antibiotic-resistant bacteria present an emerging challenge to human health. Their prevalence has been increasing across the globe due in part to the liberal use of antibiotics that has pressured them to develop resistance. Those bacteria that acquire mobile genetic elements are especially concerning because those plasmids may be shared readily with other microbes that can then also become antibiotic resistant. Serious infections have recently been related to the contamination of preservative-free eyedrops with extensively drug-resistant (XDR) isolates of Pseudomonas aeruginosa, already resulting in three deaths. These drug-resistant isolates cannot be managed with most conventional antibiotics. We sought to identify alternatives to conventional antibiotics for the lysis of these XDR isolates and identified multiple bacteriophages (viruses that attack bacteria) that killed them efficiently. We found both jumbo phages (>200 kb in genome size) and non-jumbo phages that were active against these isolates, the former killing more efficiently. Jumbo phages effectively killed the three separate XDR P. aeruginosa isolates both on solid and liquid medium. Given the ongoing nature of the XDR P. aeruginosa eyedrop outbreak, the identification of phages active against them provides physicians with several novel potential alternatives for treatment.
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Affiliation(s)
| | - Pooja Ghatbale
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Alisha N. Blanc
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Chase J. Morgan
- Department of Biology, University of California San Diego, La Jolla, California, USA
| | - Andrew Garcia
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Jesse Leonard
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Lina Huang
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Grace Kovalick
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Marissa Proost
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Megan Chiu
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Peiting Kuo
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Joseph Oh
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Smruthi Karthikeyan
- Department of Environmental Science and Engineering, Division of Engineering and Applied Science, California Institute of Technology, Pasadena, California, USA
- Department of Pediatrics, University of California San Diego, La Jolla, California, USA
| | - Rob Knight
- Department of Pediatrics, University of California San Diego, La Jolla, California, USA
- Center for Microbiome Innovation, University of California San Diego, La Jolla, California, USA
- Department of Bioengineering, University of California San Diego, La Jolla, California, USA
- Department of Computer Sciences & Engineering, University of California San Diego, La Jolla, California, USA
| | - Joe Pogliano
- Department of Biology, University of California San Diego, La Jolla, California, USA
- Howard Hughes Medical Institute, University of California San Diego, La Jolla, California, USA
| | - Robert T. Schooley
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - David T. Pride
- Department of Pathology, University of California San Diego, La Jolla, California, USA
- Howard Hughes Medical Institute, University of California San Diego, La Jolla, California, USA
- Department of Medicine, University of California San Diego, La Jolla, California, USA
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Khong E, Oh J, Jimenez JM, Liu R, Dunham S, Monsibais A, Rhoads A, Ghatbale P, Garcia A, Cobián Güemes AG, Blanc AN, Chiu M, Kuo P, Proost M, Kline A, Aslam S, Schooley RT, Whiteson K, Fraley SI, Pride DT. A simple solid media assay for detection of synergy between bacteriophages and antibiotics. bioRxiv 2023:2023.08.23.554535. [PMID: 37662290 PMCID: PMC10473724 DOI: 10.1101/2023.08.23.554535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
The emergence of antibiotic resistant bacteria (ARB) has necessitated the development of alternative therapies to deal with this global threat. Bacteriophages (viruses that target bacteria) that kill ARB are one such alternative. While phages have been used clinically for decades with inconsistent results, a number of recent advances in phage selection, propagation and purification have enabled a reevaluation of their utility in contemporary clinical medicine. In most phage therapy cases, phages are administered in combination with antibiotics to ensure that patients receive the standard-of-care treatment. Some phages may work cooperatively with antibiotics to eradicate ARB, as often determined using non-standardized broth assays. We sought to develop a solid media-based assay to assess cooperativity between antibiotics and phages to offer a standardized platform for such testing. We modeled the interactions that occur between antibiotics and phages on solid medium to measure additive, antagonistic, and synergistic interactions. We then tested the method using different bacterial isolates, and identified a number of isolates where synergistic interactions were identified. These interactions were not dependent on the specific organism, phage family, or antibiotic used. A priori susceptibility to the antibiotic or the specific phage were not requirements to observe synergistic interactions. Our data also confirm the potential for the restoration of vancomycin to treat Vancomycin Resistant Enterococcus (VRE) when used in combination with phages. Solid media assays for the detection of cooperative interactions between antibiotics and phages can be an accessible technique adopted by clinical laboratories to evaluate antibiotic and phage choices in phage therapy.
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Sah GP, Kovalick G, Chopyk J, Kuo P, Huang L, Ghatbale P, Das P, Realegeno S, Knight R, Gilbert JA, Pride DT. Characterization of SARS-CoV-2 Distribution and Microbial Succession in a Clinical Microbiology Testing Facility during the SARS-CoV-2 Pandemic. Microbiol Spectr 2023; 11:e0450922. [PMID: 36916973 PMCID: PMC10100919 DOI: 10.1128/spectrum.04509-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Accepted: 02/11/2023] [Indexed: 03/15/2023] Open
Abstract
The exchange of microbes between humans and the built environment is a dynamic process that has significant impact on health. Most studies exploring the microbiome of the built environment have been predicated on improving our understanding of pathogen emergence, persistence, and transmission. Previous studies have demonstrated that SARS-CoV-2 presence significantly correlates with the proportional abundance of specific bacteria on surfaces in the built environment. However, in these studies, SARS-CoV-2 originated from infected patients. Here, we perform a similar assessment for a clinical microbiology lab while staff were handling SARS-CoV-2 infected samples. The goal of this study was to understand the distribution and dynamics of microbial population on various surfaces within different sections of a clinical microbiology lab during a short period of 2020 Coronavirus disease (COVID-19) pandemic. We sampled floors, benches, and sinks in 3 sections (bacteriology, molecular microbiology, and COVID) of an active clinical microbiology lab over a 3-month period. Although floor samples harbored SARS-CoV-2, it was rarely identified on other surfaces, and bacterial diversity was significantly greater on floors than sinks and benches. The floors were primarily colonized by bacteria common to natural environments (e.g., soils), and benchtops harbored a greater proportion of human-associated microbes, including Staphylococcus and Streptococcus. Finally, we show that the microbial composition of these surfaces did not change over time and remained stable. Despite finding viruses on the floors, no lab-acquired infections were reported during the study period, which suggests that lab safety protocols and sanitation practices were sufficient to prevent pathogen exposures. IMPORTANCE For decades, diagnostic clinical laboratories have been an integral part of the health care systems that perform diagnostic tests on patient's specimens in bulk on a regular basis. Understanding their microbiota should assist in designing and implementing disinfection, and cleaning regime in more effective way. To our knowledge, there is a lack of information on the composition and dynamics of microbiota in the clinical laboratory environments, and, through this study, we have tried to fill that gap. This study has wider implications as understanding the makeup of microbes on various surfaces within clinical laboratories could help identify any pathogenic bacterial taxa that could have colonized these surfaces, and might act as a potential source of laboratory-acquired infections. Mapping the microbial community within these built environments may also be critical in assessing the reliability of laboratory safety and sanitation practices to lower any potential risk of exposures to health care workers.
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Affiliation(s)
- Govind Prasad Sah
- Department of Pathology, University of California San Diego, San Diego, California, USA
| | - Grace Kovalick
- Department of Pathology, University of California San Diego, San Diego, California, USA
| | - Jessica Chopyk
- Department of Pathology, University of California San Diego, San Diego, California, USA
| | - Peiting Kuo
- Department of Pathology, University of California San Diego, San Diego, California, USA
| | - Lina Huang
- Department of Medicine, University of California San Diego, San Diego, California, USA
| | - Pooja Ghatbale
- Department of Pathology, University of California San Diego, San Diego, California, USA
| | - Promi Das
- Department of Pediatrics, University of California San Diego, San Diego, California, USA
- Center for Microbiome Innovation, University of California San Diego, San Diego, California, USA
| | - Susan Realegeno
- Department of Pathology, University of California San Diego, San Diego, California, USA
| | - Rob Knight
- Department of Pediatrics, University of California San Diego, San Diego, California, USA
- Center for Microbiome Innovation, University of California San Diego, San Diego, California, USA
- Department of Bioengineering, University of California San Diego, San Diego, California, USA
- Department of Computer Science & Engineering, University of California San Diego, San Diego, California, USA
| | - Jack A. Gilbert
- Department of Pediatrics, University of California San Diego, San Diego, California, USA
- Center for Microbiome Innovation, University of California San Diego, San Diego, California, USA
- Scripps Institution of Oceanography and Department of Pediatrics, University of California San Diego, San Diego, California, USA
| | - David T. Pride
- Department of Pathology, University of California San Diego, San Diego, California, USA
- Department of Medicine, University of California San Diego, San Diego, California, USA
- Center for Microbiome Innovation, University of California San Diego, San Diego, California, USA
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