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High level of persister frequency in clinical staphylococcal isolates

BACKGROUND: Staphylococcus aureus is a notorious human pathogen that causes often lethal systemic conditions that are mostly medical device associated biofilm infections. Similarly, coagulase negative staphylococci are emerging as leading pathogen for nosocomial infections owing to their ability to...

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Autores principales: Manandhar, Sarita, Singh, Anjana, Varma, Ajit, Pandey, Shanti, Shrivastava, Neeraj
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10124895/
https://www.ncbi.nlm.nih.gov/pubmed/35448965
http://dx.doi.org/10.1186/s12866-022-02529-7
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author Manandhar, Sarita
Singh, Anjana
Varma, Ajit
Pandey, Shanti
Shrivastava, Neeraj
author_facet Manandhar, Sarita
Singh, Anjana
Varma, Ajit
Pandey, Shanti
Shrivastava, Neeraj
author_sort Manandhar, Sarita
collection PubMed
description BACKGROUND: Staphylococcus aureus is a notorious human pathogen that causes often lethal systemic conditions that are mostly medical device associated biofilm infections. Similarly, coagulase negative staphylococci are emerging as leading pathogen for nosocomial infections owing to their ability to form biofilm on implanted medical equipment. Chronic in nature, these infections are difficult to treat. Such recalcitrance of these infections is caused mainly due to the presence of persister cells, which exhibit transient yet extreme tolerance to antibiotics. Despite tremendous clinical significance, there is lack of studies on persister cells formation among clinical bacterial isolates. Considering the importance of factors influencing persister formation, in this study, we evaluate the association of antibiotic tolerance with biofilm production, antibiotic stress, growth phase, specimen type, and dependency on staphylococcal species. Biofilm formation was detected among 375 clinical staphylococcal isolates by quantitative tissue culture plate method (TCP) and icaAD genes by genotypic method. The antibiotic susceptibility was determined by Kirby Bauer disc diffusion method while minimum inhibitory concentration values were obtained by agar dilution method. Persister cells were measured in the susceptible staphylococcal isolates in the presence of clinically relevant antibiotics. RESULTS: In the study, 161 (43%) S. aureus and 214 (57%) coagulase negative staphylococci (CNS) were isolated from different clinical samples. TCP method detected biofilm production in 84 (52.2%) S. aureus and 90 (42.1%) CNS isolates. The genotypic method detected icaAD genes in 86 (22.9%) isolates. Majority (> 90%) of both the biofilm producers and non-producers were sensitive to chloramphenicol and tetracycline but were resistant to penicillin. Interestingly, all isolates were sensitive to vancomycin irrespective of biofilm production. While high persister frequency was observed among all staphylococci isolates in the stationary growth phase, the persister frequency in exponential growth phase was statistically high among isolates possessing icaAD genes compared to icaAD negative isolates. CONCLUSION: The research findings provide strong evidence that the clinical staphylococcal isolates exhibit extreme antibiotic tolerance suggesting their causal link with treatment failures. Understanding the factors influencing the formation and maintenance of persister cells are of utmost important aspect to design therapeutics and control recalcitrant bacterial infections. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12866-022-02529-7.
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spelling pubmed-101248952023-04-25 High level of persister frequency in clinical staphylococcal isolates Manandhar, Sarita Singh, Anjana Varma, Ajit Pandey, Shanti Shrivastava, Neeraj BMC Microbiol Research BACKGROUND: Staphylococcus aureus is a notorious human pathogen that causes often lethal systemic conditions that are mostly medical device associated biofilm infections. Similarly, coagulase negative staphylococci are emerging as leading pathogen for nosocomial infections owing to their ability to form biofilm on implanted medical equipment. Chronic in nature, these infections are difficult to treat. Such recalcitrance of these infections is caused mainly due to the presence of persister cells, which exhibit transient yet extreme tolerance to antibiotics. Despite tremendous clinical significance, there is lack of studies on persister cells formation among clinical bacterial isolates. Considering the importance of factors influencing persister formation, in this study, we evaluate the association of antibiotic tolerance with biofilm production, antibiotic stress, growth phase, specimen type, and dependency on staphylococcal species. Biofilm formation was detected among 375 clinical staphylococcal isolates by quantitative tissue culture plate method (TCP) and icaAD genes by genotypic method. The antibiotic susceptibility was determined by Kirby Bauer disc diffusion method while minimum inhibitory concentration values were obtained by agar dilution method. Persister cells were measured in the susceptible staphylococcal isolates in the presence of clinically relevant antibiotics. RESULTS: In the study, 161 (43%) S. aureus and 214 (57%) coagulase negative staphylococci (CNS) were isolated from different clinical samples. TCP method detected biofilm production in 84 (52.2%) S. aureus and 90 (42.1%) CNS isolates. The genotypic method detected icaAD genes in 86 (22.9%) isolates. Majority (> 90%) of both the biofilm producers and non-producers were sensitive to chloramphenicol and tetracycline but were resistant to penicillin. Interestingly, all isolates were sensitive to vancomycin irrespective of biofilm production. While high persister frequency was observed among all staphylococci isolates in the stationary growth phase, the persister frequency in exponential growth phase was statistically high among isolates possessing icaAD genes compared to icaAD negative isolates. CONCLUSION: The research findings provide strong evidence that the clinical staphylococcal isolates exhibit extreme antibiotic tolerance suggesting their causal link with treatment failures. Understanding the factors influencing the formation and maintenance of persister cells are of utmost important aspect to design therapeutics and control recalcitrant bacterial infections. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12866-022-02529-7. BioMed Central 2022-04-21 /pmc/articles/PMC10124895/ /pubmed/35448965 http://dx.doi.org/10.1186/s12866-022-02529-7 Text en © The Author(s) 2022 https://creativecommons.org/licenses/by/4.0/Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visithttp://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) . The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/ (https://creativecommons.org/publicdomain/zero/1.0/) ) applies to the data made available in this article, unless otherwise stated in a credit line to the data.
spellingShingle Research
Manandhar, Sarita
Singh, Anjana
Varma, Ajit
Pandey, Shanti
Shrivastava, Neeraj
High level of persister frequency in clinical staphylococcal isolates
title High level of persister frequency in clinical staphylococcal isolates
title_full High level of persister frequency in clinical staphylococcal isolates
title_fullStr High level of persister frequency in clinical staphylococcal isolates
title_full_unstemmed High level of persister frequency in clinical staphylococcal isolates
title_short High level of persister frequency in clinical staphylococcal isolates
title_sort high level of persister frequency in clinical staphylococcal isolates
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10124895/
https://www.ncbi.nlm.nih.gov/pubmed/35448965
http://dx.doi.org/10.1186/s12866-022-02529-7
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