1
|
Nurjadi D, Chanthalangsy Q, Zizmann E, Stuermer V, Moll M, Klein S, Boutin S, Heeg K, Zanger P. Phenotypic Detection of Hemin-Inducible Trimethoprim-Sulfamethoxazole Heteroresistance in Staphylococcus aureus. Microbiol Spectr 2021; 9:e0151021. [PMID: 34704796 PMCID: PMC8549745 DOI: 10.1128/spectrum.01510-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 09/17/2021] [Indexed: 11/29/2022] Open
Abstract
Trimethoprim-sulfamethoxazole (SXT) is a valuable second-line antimicrobial agent to treat methicillin-resistant Staphylococcus aureus infections. Discrepancies between various antibiotic susceptibility testing (AST) methods for SXT susceptibility in S. aureus have been described. Here, we describe a hemin-inducible heteroresistance phenotype in S. aureus. We compared the results of the Vitek 2 AST on a set of 95 S. aureus clinical isolates with broth microdilution, disk diffusion using standard Mueller-Hinton agar, and disk diffusion using Mueller-Hinton agar supplemented with 5% horse blood (MHF). To investigate the potential clinical relevance of SXT heteroresistance, an in vivo Galleria mellonella infection assay was performed. All Vitek 2 SXT-susceptible (n = 17) isolates were concordant with AST results by other methods applied in this study. In 32/78 (41%) of Vitek 2 SXT-resistant isolates, we observed a heteroresistant growth phenotype on MHF. The heteroresistance phenotype was associated with the presence of dfr genes, encoding trimethoprim resistance. The addition of a hemin-impregnated disk in a double disk diffusion method on standard Mueller-Hinton agar was able to induce growth in the SXT zone of inhibition. An in vivo infection assay with G. mellonella suggested that the SXT heteroresistance phenotype resulted in lethality similar to that of the SXT-resistant phenotype. In this study, we describe a novel hemin-inducible heteroresistance phenotype in S. aureus. This heteroresistance phenotype may be missed by standard AST methods but can be detected by performing disk diffusion using Mueller-Hinton agar supplemented with 5% horse blood, commonly used for AST of fastidious organisms. This phenomenon may partly explain the discrepancies of AST methods in determining SXT resistance in S. aureus. IMPORTANCE Staphylococcus aureus is one of most important pathogens in clinical medicine. Besides its virulence, the acquisition or emergence of resistance toward antibiotic agents, in particular to beta-lactam antibiotics (methicillin-resistant S. aureus [MRSA]), poses a major therapeutic challenge. Trimethoprim-sulfamethoxazole (SXT) is one of the effective antimicrobial agents of last resort to treat MRSA infections. Here, we report the detection of a SXT-heteroresistant phenotype which is inducible by hemin and can be detected using Mueller-Hinton agar supplemented with horse blood. Heteroresistance describes the presence or emergence of resistant subpopulations, which may potentially lead to inaccurate antibiotic susceptibility testing results and influence the success of antibiotic therapy.
Collapse
Affiliation(s)
- Dennis Nurjadi
- Department of Infectious Diseases, Medical Microbiology, and Hygiene, Heidelberg University Hospital, Heidelberg, Germany
| | - Quan Chanthalangsy
- Department of Infectious Diseases, Medical Microbiology, and Hygiene, Heidelberg University Hospital, Heidelberg, Germany
| | - Elfi Zizmann
- Department of Infectious Diseases, Medical Microbiology, and Hygiene, Heidelberg University Hospital, Heidelberg, Germany
| | - Vanessa Stuermer
- Department of Infectious Diseases, Medical Microbiology, and Hygiene, Heidelberg University Hospital, Heidelberg, Germany
| | - Maximilian Moll
- Department of Infectious Diseases, Medical Microbiology, and Hygiene, Heidelberg University Hospital, Heidelberg, Germany
| | - Sabrina Klein
- Department of Infectious Diseases, Medical Microbiology, and Hygiene, Heidelberg University Hospital, Heidelberg, Germany
| | - Sébastien Boutin
- Department of Infectious Diseases, Medical Microbiology, and Hygiene, Heidelberg University Hospital, Heidelberg, Germany
| | - Klaus Heeg
- Department of Infectious Diseases, Medical Microbiology, and Hygiene, Heidelberg University Hospital, Heidelberg, Germany
| | - Philipp Zanger
- Department of Infectious Diseases, Medical Microbiology, and Hygiene, Heidelberg University Hospital, Heidelberg, Germany
- Heidelberg Institute of Global Health, Heidelberg University Hospital, Heidelberg, Germany
| |
Collapse
|
2
|
Braid HR, Ireland JL. A cross‐sectional survey of the diagnosis and treatment of distal limb cellulitis in horses by veterinary surgeons in the United Kingdom. EQUINE VET EDUC 2021. [DOI: 10.1111/eve.13484] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- H. R. Braid
- Institute of Infection, Veterinary & Ecological Sciences Faculty of Health and Life Sciences The University of Liverpool Neston, Wirral UK
| | - J. L. Ireland
- Institute of Infection, Veterinary & Ecological Sciences Faculty of Health and Life Sciences The University of Liverpool Neston, Wirral UK
| |
Collapse
|
3
|
Lopes SP, Jorge P, Sousa AM, Pereira MO. Discerning the role of polymicrobial biofilms in the ascent, prevalence, and extent of heteroresistance in clinical practice. Crit Rev Microbiol 2021; 47:162-191. [PMID: 33527850 DOI: 10.1080/1040841x.2020.1863329] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Antimicrobial therapy is facing a worrisome and underappreciated challenge, the phenomenon of heteroresistance (HR). HR has been gradually documented in clinically relevant pathogens (e.g. Pseudomonas aeruginosa, Staphylococcus aureus, Burkholderia spp., Acinetobacter baumannii, Klebsiella pneumoniae, Candida spp.) towards several drugs and is believed to complicate the clinical picture of chronic infections. This type of infections are typically mediated by polymicrobial biofilms, wherein microorganisms inherently display a wide range of physiological states, distinct metabolic pathways, diverging refractory levels of stress responses, and a complex network of chemical signals exchange. This review aims to provide an overview on the relevance, prevalence, and implications of HR in clinical settings. Firstly, related terminologies (e.g. resistance, tolerance, persistence), sometimes misunderstood and overlapped, were clarified. Factors generating misleading HR definitions were also uncovered. Secondly, the recent HR incidences reported in clinically relevant pathogens towards different antimicrobials were annotated. The potential mechanisms underlying such occurrences were further elucidated. Finally, the link between HR and biofilms was discussed. The focus was to recognize the presence of heterogeneous levels of resistance within most biofilms, as well as the relevance of polymicrobial biofilms in chronic infectious diseases and their role in resistance spreading. These topics were subject of a critical appraisal, gaining insights into the ascending clinical implications of HR in antimicrobial resistance spreading, which could ultimately help designing effective therapeutic options.
Collapse
Affiliation(s)
- Susana Patrícia Lopes
- CEB - Centre of Biological Engineering, LIBRO - Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
| | - Paula Jorge
- CEB - Centre of Biological Engineering, LIBRO - Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
| | - Ana Margarida Sousa
- CEB - Centre of Biological Engineering, LIBRO - Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
| | - Maria Olívia Pereira
- CEB - Centre of Biological Engineering, LIBRO - Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
| |
Collapse
|