1
|
Turner RJ. The good, the bad, and the ugly of metals as antimicrobials. Biometals 2024; 37:545-559. [PMID: 38112899 PMCID: PMC11101337 DOI: 10.1007/s10534-023-00565-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Accepted: 11/18/2023] [Indexed: 12/21/2023]
Abstract
We are now moving into the antimicrobial resistance (AMR) era where more antibiotic resistant bacteria are now the majority, a problem brought on by both misuse and over use of antibiotics. Unfortunately, the antibiotic development pipeline dwindled away over the past decades as they are not very profitable compounds for companies to develop. Regardless researchers over the past decade have made strides to explore alternative options and out of this we see revisiting historical infection control agents such as toxic metals. From this we now see a field of research exploring the efficacy of metal ions and metal complexes as antimicrobials. Such antimicrobials are delivered in a variety of forms from metal salts, alloys, metal complexes, organometallic compounds, and metal based nanomaterials and gives us the broad term metalloantimicrobials. We now see many effective formulations applied for various applications using metals as antimicrobials that are effective against drug resistant strains. The purpose of the document here is to step aside and begin a conversation on the issues of use of such toxic metal compounds against microbes. This critical opinion mini-review in no way aims to be comprehensive. The goal here is to understand the benefits of metalloantimicrobials, but also to consider strongly the disadvantages of using metals, and what are the potential consequences of misuse and overuse. We need to be conscious of the issues, to see the entire system and affect through a OneHealth vision.
Collapse
Affiliation(s)
- Raymond J Turner
- Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB, Canada.
| |
Collapse
|
2
|
Hackemann VCJ, Hagel S, Jandt KD, Rödel J, Löffler B, Tuchscherr L. The Controversial Effect of Antibiotics on Methicillin-Sensitive S. aureus: A Comparative In Vitro Study. Int J Mol Sci 2023; 24:16308. [PMID: 38003500 PMCID: PMC10671744 DOI: 10.3390/ijms242216308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 11/06/2023] [Accepted: 11/09/2023] [Indexed: 11/26/2023] Open
Abstract
Methicillin-sensitive Staphylococcus (S.) aureus (MSSA) bacteremia remains a global challenge, despite the availability of antibiotics. Primary treatments include β-lactam agents such as cefazolin and flucloxacillin. Ongoing discussions have focused on the potential synergistic effects of combining these agents with rifampicin or fosfomycin to combat infections associated with biofilm formation. Managing staphylococcal infections is challenging due to antibacterial resistance, biofilms, and S. aureus's ability to invade and replicate within host cells. Intracellular invasion shields the bacteria from antibacterial agents and the immune system, often leading to incomplete bacterial clearance and chronic infections. Additionally, S. aureus can assume a dormant phenotype, known as the small colony variant (SCV), further complicating eradication and promoting persistence. This study investigated the impact of antibiotic combinations on the persistence of S. aureus 6850 and its stable small colony variant (SCV strain JB1) focusing on intracellular survival and biofilm formation. The results from the wild-type strain 6850 demonstrate that β-lactams combined with RIF effectively eliminated biofilms and intracellular bacteria but tend to select for SCVs in planktonic culture and host cells. Higher antibiotic concentrations were associated with an increase in the zeta potential of S. aureus, suggesting reduced membrane permeability to antimicrobials. When using the stable SCV mutant strain JB1, antibiotic combinations with rifampicin successfully cleared planktonic bacteria and biofilms but failed to eradicate intracellular bacteria. Given these findings, it is reasonable to report that β-lactams combined with rifampicin represent the optimal treatment for MSSA bacteremia. However, caution is warranted when employing this treatment over an extended period, as it may elevate the risk of selecting for small colony variants (SCVs) and, consequently, promoting bacterial persistence.
Collapse
Affiliation(s)
| | - Stefan Hagel
- Institute of Infectious Diseases and Infection Control, Jena University Hospital, 07747 Jena, Germany
| | - Klaus D Jandt
- Otto Schott Institute of Materials Research (OSIM), Friedrich Schiller University Jena, 07743 Jena, Germany
- Jena School for Microbial Communication (JSMC), 07743 Jena, Germany
| | - Jürgen Rödel
- Institute for Medical Microbiology, Jena University Hospital, 07747 Jena, Germany
| | - Bettina Löffler
- Institute for Medical Microbiology, Jena University Hospital, 07747 Jena, Germany
| | - Lorena Tuchscherr
- Institute for Medical Microbiology, Jena University Hospital, 07747 Jena, Germany
| |
Collapse
|
3
|
Jin Q, Xie X, Zhai Y, Zhang H. Mechanisms of folate metabolism-related substances affecting Staphylococcus aureus infection. Int J Med Microbiol 2023; 313:151577. [PMID: 36841056 DOI: 10.1016/j.ijmm.2023.151577] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 01/28/2023] [Accepted: 02/15/2023] [Indexed: 02/18/2023] Open
Abstract
Staphylococcus aureus (S. aureus) is one of the critical clinical pathogens which can cause multiple diseases ranging from skin infections to fatal sepsis. S. aureus is generally considered to be an extracellular pathogen. However, more and more evidence has shown that S. aureus can survive inside various cells. Folate plays an essential role in multiple life activities, including the conversion of serine and glycine, the remethylation of homocysteine to methionine, and the de novo synthesis of purine /dTMP, et al. More and more studies reported that S. aureus intracellular infection requires the involvement of folate metabolism. This review focused on the mechanisms of folate metabolism and related substances affecting S. aureus infection. Loss of tetrahydrofolic acid (THF)-dependent dTMP directly inhibits the nucleotide synthesis pathway of the S. aureus due to pabA deficiency. Besides, trimethoprim-sulfamethoxazole (TMP/SMX), a potent antibiotic that treats S. aureus infections, interferes in the process of the folate mechanism and leads to the production of thymidine-dependent small-colony variants (TD-SCVs). In addition, S. aureus is resistant to lysostaphin in the presence of serine hydroxymethyltransferase (SHMT). We provide new insights for understanding the molecular pathogenesis of S. aureus infection.
Collapse
Affiliation(s)
- Qiyuan Jin
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Xiaolu Xie
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Yaxuan Zhai
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Haifang Zhang
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, China.
| |
Collapse
|
4
|
Pacocha N, Zapotoczna M, Makuch K, Bogusławski J, Garstecki P. You will know by its tail: a method for quantification of heterogeneity of bacterial populations using single-cell MIC profiling. LAB ON A CHIP 2022; 22:4317-4326. [PMID: 36222371 DOI: 10.1039/d2lc00234e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Severe non-healing infections are often caused by multiple pathogens or by genetic variants of the same pathogen exhibiting different levels of antibiotic resistance. For example, polymicrobial diabetic foot infections double the risk of amputation compared to monomicrobial infections. Although these infections lead to increased morbidity and mortality, standard antimicrobial susceptibility methods are designed for homogenous samples and are impaired in quantifying heteroresistance. Here, we propose a droplet-based label-free method for quantifying the antibiotic response of the entire population at the single-cell level. We used Pseudomonas aeruginosa and Staphylococcus aureus samples to confirm that the shape of the profile informs about the coexistence of diverse bacterial subpopulations, their sizes, and antibiotic heteroresistance. These profiles could therefore indicate the outcome of antibiotic treatment in terms of the size of remaining subpopulations. Moreover, we studied phenotypic variants of a S. aureus strain to confirm that the profile can be used to identify tolerant subpopulations, such as small colony variants, associated with increased risks for the development of persisting infections. Therefore, the profile is a versatile instrument for quantifying the size of each bacterial subpopulation within a specimen as well as their individual and joined heteroresistance.
Collapse
Affiliation(s)
- Natalia Pacocha
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
| | - Marta Zapotoczna
- Department of Molecular Microbiology, Institute of Microbiology, Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Karol Makuch
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
| | - Jakub Bogusławski
- International Centre for Translational Eye Research, Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
- Department of Physical Chemistry of Biological Systems, Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
- Laser & Fiber Electronics Group, Faculty of Electronics, Wrocław University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
| | - Piotr Garstecki
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
| |
Collapse
|
5
|
Keim KC, George IK, Reynolds L, Smith AC. The Clinical Significance of Staphylococcus aureus Small Colony Variants. Lab Med 2022; 54:227-234. [PMID: 36226897 DOI: 10.1093/labmed/lmac101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Abstract
A burdensome, atypical phenotype of Staphylococcus aureus (SA) called S aureus small colony variant (SA-SCV) has been identified, which is induced as a result of a combination of environmental stressors, including polymicrobial interactions. The SA-SCVs exhibit altered phenotypes as a result of metabolic dormancy caused by electron transport deficiency, leading to increased biofilm production and alterations to antimicrobial susceptibility. The SA-SCVs typically exhibit altered colony morphology and biochemical reactions compared with wild-type SA, making them difficult to detect via routine diagnostics. The SA-SCVs have been found to contribute to chronic or recurrent infections, including skin and soft-tissue infections, foreign-body associated infection, cystic fibrosis, and sepsis. There is evidence that SA-SCVs contribute to patient morbidity and mortality as a result of diagnostic difficulties and limited treatment options. New detection methods may need to be developed that can be incorporated into routine diagnostics, which would allow for better assessment of specimens and introduce new considerations for treatment.
Collapse
Affiliation(s)
- Klara C Keim
- Department of Immunology and Microbiology, School of Medicine, Anschutz Medical Campus, University of Colorado , Aurora, CO , USA
| | - Isaiah K George
- Department of Honors Studies, Texas Tech University , Lubbock, TX , USA
| | - Landrye Reynolds
- Department of Honors Studies, Texas Tech University , Lubbock, TX , USA
| | - Allie C Smith
- Department of Honors Studies, Texas Tech University , Lubbock, TX , USA
| |
Collapse
|
6
|
Biggs SL, Jennison AV, Bergh H, Graham R, Nimmo G, Whiley D. Limited evidence of patient-to-patient transmission of Staphylococcus aureus strains between children with cystic fibrosis, Queensland, Australia. PLoS One 2022; 17:e0275256. [PMID: 36206247 PMCID: PMC9543978 DOI: 10.1371/journal.pone.0275256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Accepted: 09/13/2022] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVES Here we used whole genome sequencing (WGS) to understand strain diversity and potential for patient-to-patient transmission of Staphylococcus aureus among children with cystic fibrosis (CF) in Queensland, Australia. METHODS S. aureus isolates (n = 401) collected between January 2018 and April 2019 from 184 patients with CF (n = 318 isolates) and 76 patients without CF (n = 83 isolates) were subjected to WGS and subsequent multilocus sequence typing (MLST), and a phylogeny was constructed from core genome single nucleotide polymorphism (SNP) analysis. The subsequent data was compared with available patient information. RESULTS WGS revealed that patients with CF were essentially colonised by the same genotypes as those seen in patients without CF. Sequence types (ST) for our patients with CF were predominantly ST5 (20.1%), ST30 (7.3%), ST15 (6.3%) and ST8 (5.3%). Two Australian clones, ST93 and ST239, typically seen in skin infections and health-care settings, respectively, were notably absent from our patients with CF. Based on a SNP distance threshold of 14 SNPs, 20 cluster types involving 50/260 patients were evident; of these, 6 clusters contained only patients found to be siblings or otherwise living in the same household. Epidemiological relationships could not be determined for a remaining 14 cluster types involving 38 patients, comprising 2-7 (median 2) patients each. Multiple S. aureus genotypes were observed in 19/73 CF patients who provided more than one sample. CONCLUSION These results show that WGS is a useful tool for surveillance of S. aureus strains in children with CF and that the strains in our CF cohort were largely consistent with those circulating in patients without CF. Overall, this confirms previous findings and indicates that S. aureus acquisition in children with CF is similar to that of other patient groups, with limited evidence of potential patient-to-patient transmission within this patient group.
Collapse
Affiliation(s)
- Sharon L. Biggs
- School of Medicine, The University of Queensland, UQ Centre for Clinical Research (UQCCR), Herston, Queensland, Australia
| | - Amy V. Jennison
- Public and Environmental Health, Forensic and Scientific Services, Coopers Plains, Queensland, Australia
| | - Haakon Bergh
- Pathology Queensland Central Laboratory, Herston, Queensland, Australia
| | - Rikki Graham
- Public and Environmental Health, Forensic and Scientific Services, Coopers Plains, Queensland, Australia
| | - Graeme Nimmo
- School of Medicine, Griffith University, Gold Coast, Queensland, Australia
| | - David Whiley
- School of Medicine, The University of Queensland, UQ Centre for Clinical Research (UQCCR), Herston, Queensland, Australia
- Pathology Queensland Central Laboratory, Herston, Queensland, Australia
- * E-mail:
| |
Collapse
|
7
|
Guo H, Tong Y, Cheng J, Abbas Z, Li Z, Wang J, Zhou Y, Si D, Zhang R. Biofilm and Small Colony Variants-An Update on Staphylococcus aureus Strategies toward Drug Resistance. Int J Mol Sci 2022; 23:ijms23031241. [PMID: 35163165 PMCID: PMC8835882 DOI: 10.3390/ijms23031241] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/16/2022] [Accepted: 01/20/2022] [Indexed: 02/07/2023] Open
Abstract
Recently, the drawbacks arising from the overuse of antibiotics have drawn growing public attention. Among them, drug-resistance (DR) and even multidrug-resistance (MDR) pose significant challenges in clinical practice. As a representative of a DR or MDR pathogen, Staphylococcus aureus can cause diversity of infections related to different organs, and can survive or adapt to the diverse hostile environments by switching into other phenotypes, including biofilm and small colony variants (SCVs), with altered physiologic or metabolic characteristics. In this review, we briefly describe the development of the DR/MDR as well as the classical mechanisms (accumulation of the resistant genes). Moreover, we use multidimensional scaling analysis to evaluate the MDR relevant hotspots in the recent published reports. Furthermore, we mainly focus on the possible non-classical resistance mechanisms triggered by the two important alternative phenotypes of the S. aureus, biofilm and SCVs, which are fundamentally caused by the different global regulation of the S. aureus population, such as the main quorum-sensing (QS) and agr system and its coordinated regulated factors, such as the SarA family proteins and the alternative sigma factor σB (SigB). Both the biofilm and the SCVs are able to escape from the host immune response, and resist the therapeutic effects of antibiotics through the physical or the biological barriers, and become less sensitive to some antibiotics by the dormant state with the limited metabolisms.
Collapse
|
8
|
Mixed Populations and Co-Infection: Pseudomonas aeruginosa and Staphylococcus aureus. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:397-424. [DOI: 10.1007/978-3-031-08491-1_15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
9
|
Altwiley D, Brignoli T, Edwards A, Recker M, Lee JC, Massey RC. A functional menadione biosynthesis pathway is required for capsule production by Staphylococcus aureus. MICROBIOLOGY (READING, ENGLAND) 2021; 167. [PMID: 34825882 PMCID: PMC8743628 DOI: 10.1099/mic.0.001108] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Staphylococcus aureus is a major human pathogen that utilises a wide array of pathogenic and immune evasion strategies to cause disease. One immune evasion strategy, common to many bacterial pathogens, is the ability of S. aureus to produce a capsule that protects the bacteria from several aspects of the human immune system. To identify novel regulators of capsule production by S. aureus, we applied a genome wide association study (GWAS) to a collection of 300 bacteraemia isolates that represent the two major MRSA clones in UK and Irish hospitals: CC22 and CC30. One of the loci associated with capsule production, the menD gene, encodes an enzyme critical to the biosynthesis of menadione. Mutations in this gene that result in menadione auxotrophy induce the slow growing small-colony variant (SCV) form of S. aureus often associated with chronic infections due to their increased resistance to antibiotics and ability to survive inside phagocytes. Utilising such an SCV, we functionally verified this association between menD and capsule production. Although the clinical isolates with polymorphisms in the menD gene in our collections had no apparent growth defects, they were more resistant to gentamicin when compared to those with the wild-type menD gene. Our work suggests that menadione is involved in the production of the S. aureus capsule, and that amongst clinical isolates polymorphisms exist in the menD gene that confer the characteristic increased gentamicin resistance, but not the major growth defect associated with SCV phenotype.
Collapse
Affiliation(s)
- Dina Altwiley
- School of Cellular and Molecular Medicine, University of Bristol, BS8 1TD, UK.,University of Jeddah, Saudi Arabia
| | - Tarcisio Brignoli
- School of Cellular and Molecular Medicine, University of Bristol, BS8 1TD, UK
| | - Andrew Edwards
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2AZ, UK
| | - Mario Recker
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, TR10 9FE, UK
| | - Jean C Lee
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Ruth C Massey
- School of Cellular and Molecular Medicine, University of Bristol, BS8 1TD, UK.,Schools of Microbiology and Medicine, and APC Microbiome Ireland, University College Cork, Ireland
| |
Collapse
|
10
|
Emergence of Thymidine-Dependent Staphylococcus aureus Small-Colony Variants in Cystic Fibrosis Patients in Southern Brazil. Microbiol Spectr 2021; 9:e0061421. [PMID: 34319160 PMCID: PMC8552798 DOI: 10.1128/spectrum.00614-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We characterized Staphylococcus aureus small-colony variant (SCV) strains isolated from cystic fibrosis (CF) patients in southern Brazil. Smaller colonies of S. aureus were isolated from respiratory samples collected consecutively from 225 CF patients from July 2013 to November 2016. Two phenotypic methods—the auxotrophic classification and a modified method of antimicrobial susceptibility testing—were employed. PCR was conducted to detect the mecA, ermA, ermB, ermC, msrA, and msrB resistance genes. Furthermore, DNA sequencing was performed to determine the mutations in the thyA gene, and multilocus sequence typing was used to identify the genetic relatedness. S. aureus strains were isolated from 186 patients (82%); suggestive colonies of SCVs were obtained in 16 patients (8.6%). The clones CC1 (ST1, ST188, and ST2383), CC5 (ST5 and ST221), and ST398 were identified. Among SCVs, antimicrobial susceptibility testing showed that 77.7% of the isolates were resistant to multiple drugs, and all of them were susceptible to vancomycin. mecA (2), ermA (1), ermB (1), ermC (3), and msrB (18) were distributed among the isolates. Phenotypically thymidine-dependent isolates had different mutations in the thyA gene, and frameshift mutations were frequently observed. Of note, revertants showed nonconservative or conservative missense mutations. SCVs are rarely identified in routine laboratory tests. IMPORTANCE Similar findings have not yet been reported in Brazil, emphasizing the importance of monitoring small-colony variants (SCVs). Altogether, our results highlight the need to improve detection methods and review antimicrobial therapy protocols in cystic fibrosis (CF) patients.
Collapse
|
11
|
Bogut A, Magryś A. The road to success of coagulase-negative staphylococci: clinical significance of small colony variants and their pathogenic role in persistent infections. Eur J Clin Microbiol Infect Dis 2021; 40:2249-2270. [PMID: 34296355 PMCID: PMC8520507 DOI: 10.1007/s10096-021-04315-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Accepted: 07/09/2021] [Indexed: 01/14/2023]
Abstract
Bacterial small colony variants represent an important aspect of bacterial variability. They are naturally occurring microbial subpopulations with distinctive phenotypic and pathogenic traits, reported for many clinically important bacteria. In clinical terms, SCVs tend to be associated with persistence in host cells and tissues and are less susceptible to antibiotics than their wild-type (WT) counterparts. The increased tendency of SCVs to reside intracellularly where they are protected against the host immune responses and antimicrobial drugs is one of the crucial aspects linking SCVs to recurrent or chronic infections, which are difficult to treat. An important aspect of the SCV ability to persist in the host is the quiescent metabolic state, reduced immune response and expression a changed pattern of virulence factors, including a reduced expression of exotoxins and an increased expression of adhesins facilitating host cell uptake. The purpose of this review is to describe in greater detail the currently available data regarding CoNS SCV and, in particular, their clinical significance and possible mechanisms by which SCVs contribute to the pathogenesis of the chronic infections. It should be emphasized that in spite of an increasing clinical significance of this group of staphylococci, the number of studies unraveling the mechanisms of CoNS SCVs formation and their impact on the course of the infectious process is still scarce, lagging behind the studies on S. aureus SCVs.
Collapse
Affiliation(s)
- Agnieszka Bogut
- Chair and Department of Medical Microbiology, Medical University of Lublin, ul. Chodźki 1, 20-093, Lublin, Poland
| | - Agnieszka Magryś
- Chair and Department of Medical Microbiology, Medical University of Lublin, ul. Chodźki 1, 20-093, Lublin, Poland.
| |
Collapse
|
12
|
Methicillin-resistant Staphylococcus aureus of the clonal lineage ST5-SCCmecII-t2460 was associated with high mortality in a Wuhan hospital. Braz J Microbiol 2021; 52:1929-1936. [PMID: 34235706 PMCID: PMC8578356 DOI: 10.1007/s42770-021-00557-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 06/27/2021] [Indexed: 01/29/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is an important human pathogen that can cause serious infectious diseases. An emerging MRSA strain, ST5-SCCmecII spa-type-t2460 (SMRSA), has spread rapidly since its recent emergence in China, but little information is available about this lineage. In this study, 91 MRSA isolates were collected from patients treated in the Zhongnan Hospital, Wuhan University, from 2018 to 2019, and investigated for their molecular characteristics, antibiotic resistance profiles, and clinical characteristics. The predominant lineage, SMRSA, accounted for 37.4% (34/91) of the isolates, followed by ST239-SCCmecIII-t030 (19.8%, 18/91) and ST59-SCCmecIV-t437 (8.8%, 8/91). In contrast to the latter two non-SMRSA (nSMRSA) lineages, which are among the main MRSA found in Chinese settings, SMRSA exhibited small colony variant (SCV) phenotype and had extremely high resistance rates to erythromycin (100.0%), clindamycin (100.0%), levofloxacin (100.0%), tetracycline (97.1%), moxifloxacin (97.1%), and ciprofloxacin (100%), but was more susceptible to rifampicin (resistance rate 3%). The levels of white blood cells (WBC) and procalcitonin (PCT) and the 30-day mortality in patients infected with SMRSA were (12.54 ± 6.61) × 109/L, 0.66 ng/mL, and 52.9%, respectively, which were much higher than those in patients infected with nSMRSA. In addition, patients infected with SMRSA were more frequently admitted to the intensive care unit (ICU) and submitted to invasive procedures than those infected with nSMRSA. In conclusion, SMRSA showed SCV phenotype and exhibited multiple antibiotic-resistance profiles. In this study, SMRSA was associated with serious infections and poor prognosis. Compared with ST239, ST59, or other nSMRSA strains, patients infected with SMRSA strains have higher 30-day mortality, increased levels of inflammatory biomarkers, and more frequent ICU hospitalization and invasive procedures.
Collapse
|
13
|
|
14
|
Sato T, Uno T, Kawamura M, Fujimura S. In vitro Tolerability of Biofilm-Forming Trimethoprim-/Sulfamethoxazole-Resistant Small Colony Variants of Staphylococcus aureus Against Various Antimicrobial Agents. Microb Drug Resist 2021; 27:1282-1289. [PMID: 33689487 DOI: 10.1089/mdr.2020.0379] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Trimethoprim-/sulfamethoxazole-resistant small colony variants (SCVs) of Staphylococcus aureus, which are selected by use of trimethoprim/sulfamethoxazole, are involved in intractable biofilm-forming infection. This study aimed to determine the biofilm formation ability in trimethoprim-/sulfamethoxazole-resistant SCVs of S. aureus and investigate the bactericidal activity of differential antimicrobial agents to its biofilm-forming S. aureus. Between 32 S. aureus wild type (WT) and 32 SCVs selected from its WT, the amount of formed biofilm was compared. Vancomycin, daptomycin, rifampicin, and minocycline were exposed to biofilm-forming S. aureus to determine viable bacterial counts and its susceptibility. The biofilm-producing quantify of SCVs was approximately twice that formed by its WT. Vancomycin and daptomycin reduce 4 logs the bacterial counts of biofilm-forming WT at 24 hours, but did not affect SCVs. Rifampicin and minocycline considerably decreased both WT and SCVs; however, both bacterial counts recovered to an initial number 48 hours later. These survival strains showed resistance to each drug, and rpoB mutation or tet38 mRNA overexpression was confirmed.
Collapse
Affiliation(s)
- Takumi Sato
- Division of Clinical Infectious Diseases and Chemotherapy, Tohoku Medical and Pharmaceutical University, Sendai, Japan
| | - Takashi Uno
- Division of Clinical Infectious Diseases and Chemotherapy, Tohoku Medical and Pharmaceutical University, Sendai, Japan
| | - Masato Kawamura
- Division of Clinical Infectious Diseases and Chemotherapy, Tohoku Medical and Pharmaceutical University, Sendai, Japan
| | - Shigeru Fujimura
- Division of Clinical Infectious Diseases and Chemotherapy, Tohoku Medical and Pharmaceutical University, Sendai, Japan
| |
Collapse
|
15
|
Gor V, Ohniwa RL, Morikawa K. No Change, No Life? What We Know about Phase Variation in Staphylococcus aureus. Microorganisms 2021; 9:microorganisms9020244. [PMID: 33503998 PMCID: PMC7911514 DOI: 10.3390/microorganisms9020244] [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: 12/31/2020] [Revised: 01/22/2021] [Accepted: 01/23/2021] [Indexed: 12/13/2022] Open
Abstract
Phase variation (PV) is a well-known phenomenon of high-frequency reversible gene-expression switching. PV arises from genetic and epigenetic mechanisms and confers a range of benefits to bacteria, constituting both an innate immune strategy to infection from bacteriophages as well as an adaptation strategy within an infected host. PV has been well-characterized in numerous bacterial species; however, there is limited direct evidence of PV in the human opportunistic pathogen Staphylococcus aureus. This review provides an overview of the mechanisms that generate PV and focuses on earlier and recent findings of PV in S. aureus, with a brief look at the future of the field.
Collapse
Affiliation(s)
- Vishal Gor
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
- Correspondence: (V.G.); (K.M.)
| | - Ryosuke L. Ohniwa
- Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan;
| | - Kazuya Morikawa
- Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan;
- Correspondence: (V.G.); (K.M.)
| |
Collapse
|
16
|
Martins KB, Olmedo DWV, Paz MM, Ramos DF. Staphylococcus aureus and its Effects on the Prognosis of Bronchiectasis. Microb Drug Resist 2020; 27:823-834. [PMID: 33232626 DOI: 10.1089/mdr.2020.0352] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Bronchiectasis, which is an abnormal and irreversible dilation of one or several bronchial segments, causes significant morbidity and impaired quality of life to patients, mainly as the result of recurrent and chronic respiratory infections. Staphylococcus aureus is a microorganism known for its high infectious potential related to the production of molecules with great pathogenic power, such as enzymes, toxins, adhesins, and biofilm, which determine the degree of severity of systemic symptoms and can induce exacerbated immune response. This review highlighted the clinical significance of S. aureus colonization/infection in bronchiectasis patients, since little is known about it, despite its increasing frequency of isolation and potential serious morbidity.
Collapse
Affiliation(s)
- Katheryne Benini Martins
- Núcleo de Pesquisa em Microbiologia Médica (NUPEMM), Universidade Federal do Rio Grande-FURG, Rio Grande, Rio Grande do Sul, Brazil.,Post-graduate Program in Health Sciences-School of Medicine, Universidade Federal do Rio Grande-FURG, Rio Grande, Rio Grande do Sul, Brazil
| | - Daniel Wenceslau Votto Olmedo
- Núcleo de Pesquisa em Microbiologia Médica (NUPEMM), Universidade Federal do Rio Grande-FURG, Rio Grande, Rio Grande do Sul, Brazil.,Post-graduate Program in Health Sciences-School of Medicine, Universidade Federal do Rio Grande-FURG, Rio Grande, Rio Grande do Sul, Brazil
| | - Milene Machado Paz
- Núcleo de Pesquisa em Microbiologia Médica (NUPEMM), Universidade Federal do Rio Grande-FURG, Rio Grande, Rio Grande do Sul, Brazil.,Post-graduate Program in Health Sciences-School of Medicine, Universidade Federal do Rio Grande-FURG, Rio Grande, Rio Grande do Sul, Brazil
| | - Daniela Fernandes Ramos
- Núcleo de Pesquisa em Microbiologia Médica (NUPEMM), Universidade Federal do Rio Grande-FURG, Rio Grande, Rio Grande do Sul, Brazil.,Post-graduate Program in Health Sciences-School of Medicine, Universidade Federal do Rio Grande-FURG, Rio Grande, Rio Grande do Sul, Brazil
| |
Collapse
|
17
|
Hubbard ATM, Bulgasim I, Roberts AP. A novel hemA mutation is responsible for a small-colony-variant phenotype in Escherichia coli. MICROBIOLOGY-SGM 2020; 167. [PMID: 32762803 DOI: 10.1099/mic.0.000962] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We identified a small colony variant (SCV) of an amoxicillin/clavulanic acid-resistant derivative of a clinical isolate of Escherichia coli from Malawi, which was selected for in vitro in a subinhibitory concentration of gentamicin. The SCV was auxotrophic for hemin and had impaired biofilm formation compared to the ancestral isolates. A single novel nucleotide polymorphism (SNP) in hemA, which encodes a glutamyl-tRNA reductase that catalyses the initial step of porphyrin biosynthesis leading to the production of haem, was responsible for the SCV phenotype. We showed the SNP in hemA resulted in a significant fitness cost to the isolate, which persisted even in the presence of hemin. However, the phenotype quickly reverted during sequential sub-culturing in liquid growth media. As hemA is not found in mammalian cells, and disruption of the gene results in a significant fitness cost, it represents a potential target for novel drug development specifically for the treatment of catheter-associated urinary tract infections caused by E. coli.
Collapse
Affiliation(s)
- Alasdair T M Hubbard
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Issra Bulgasim
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Adam P Roberts
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| |
Collapse
|
18
|
Liu L, Beck C, Nøhr-Meldgaard K, Peschel A, Kretschmer D, Ingmer H, Vestergaard M. Inhibition of the ATP synthase sensitizes Staphylococcus aureus towards human antimicrobial peptides. Sci Rep 2020; 10:11391. [PMID: 32647350 PMCID: PMC7347559 DOI: 10.1038/s41598-020-68146-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 06/08/2020] [Indexed: 11/09/2022] Open
Abstract
Antimicrobial peptides (AMPs) are an important part of the human innate immune system for protection against bacterial infections, however the AMPs display varying degrees of activity against Staphylococcus aureus. Previously, we showed that inactivation of the ATP synthase sensitizes S. aureus towards the AMP antibiotic class of polymyxins. Here we wondered if the ATP synthase similarly is needed for tolerance towards various human AMPs, including human β-defensins (hBD1-4), LL-37 and histatin 5. Importantly, we find that the ATP synthase mutant (atpA) is more susceptible to killing by hBD4, hBD2, LL-37 and histatin 5 than wild type cells, while no changes in susceptibility was detected for hBD3 and hBD1. Administration of the ATP synthase inhibitor, resveratrol, sensitizes S. aureus towards hBD4-mediated killing. Neutrophils rely on AMPs and reactive oxygen molecules to eliminate bacteria and the atpA mutant is more susceptible to killing by neutrophils than the WT, even when the oxidative burst is inhibited.These results show that the staphylococcal ATP synthase enhance tolerance of S. aureus towards some human AMPs and this indicates that inhibition of the ATP synthase may be explored as a new therapeutic strategy that sensitizes S. aureus to naturally occurring AMPs of the innate immune system.
Collapse
Affiliation(s)
- Liping Liu
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, 1870, Frederiksberg C, Denmark
| | - Christian Beck
- Department of Infection Biology, Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), Cluster of Excellence 'Controlling Microbes to Fight Infections', University of Tübingen, Auf der Morgenstelle 28, 72076, Tübingen, Germany
| | - Katrine Nøhr-Meldgaard
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, 1870, Frederiksberg C, Denmark
| | - Andreas Peschel
- Department of Infection Biology, Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), Cluster of Excellence 'Controlling Microbes to Fight Infections', University of Tübingen, Auf der Morgenstelle 28, 72076, Tübingen, Germany
| | - Dorothee Kretschmer
- Department of Infection Biology, Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), Cluster of Excellence 'Controlling Microbes to Fight Infections', University of Tübingen, Auf der Morgenstelle 28, 72076, Tübingen, Germany
| | - Hanne Ingmer
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, 1870, Frederiksberg C, Denmark.
| | - Martin Vestergaard
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, 1870, Frederiksberg C, Denmark
| |
Collapse
|
19
|
Mercer DK, Torres MDT, Duay SS, Lovie E, Simpson L, von Köckritz-Blickwede M, de la Fuente-Nunez C, O'Neil DA, Angeles-Boza AM. Antimicrobial Susceptibility Testing of Antimicrobial Peptides to Better Predict Efficacy. Front Cell Infect Microbiol 2020; 10:326. [PMID: 32733816 PMCID: PMC7358464 DOI: 10.3389/fcimb.2020.00326] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 05/29/2020] [Indexed: 12/11/2022] Open
Abstract
During the development of antimicrobial peptides (AMP) as potential therapeutics, antimicrobial susceptibility testing (AST) stands as an essential part of the process in identification and optimisation of candidate AMP. Standard methods for AST, developed almost 60 years ago for testing conventional antibiotics, are not necessarily fit for purpose when it comes to determining the susceptibility of microorganisms to AMP. Without careful consideration of the parameters comprising AST there is a risk of failing to identify novel antimicrobials at a time when antimicrobial resistance (AMR) is leading the planet toward a post-antibiotic era. More physiologically/clinically relevant AST will allow better determination of the preclinical activity of drug candidates and allow the identification of lead compounds. An important consideration is the efficacy of AMP in biological matrices replicating sites of infection, e.g., blood/plasma/serum, lung bronchiolar lavage fluid/sputum, urine, biofilms, etc., as this will likely be more predictive of clinical efficacy. Additionally, specific AST for different target microorganisms may help to better predict efficacy of AMP in specific infections. In this manuscript, we describe what we believe are the key considerations for AST of AMP and hope that this information can better guide the preclinical development of AMP toward becoming a new generation of urgently needed antimicrobials.
Collapse
Affiliation(s)
| | - Marcelo D. T. Torres
- Machine Biology Group, Departments of Psychiatry and Microbiology, Institute for Biomedical Informatics, Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, Penn Institute for Computational Science, and Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States
| | - Searle S. Duay
- Department of Chemistry, Institute of Materials Science, University of Connecticut, Storrs, CT, United States
| | - Emma Lovie
- NovaBiotics Ltd, Aberdeen, United Kingdom
| | | | | | - Cesar de la Fuente-Nunez
- Machine Biology Group, Departments of Psychiatry and Microbiology, Institute for Biomedical Informatics, Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, Penn Institute for Computational Science, and Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States
| | | | - Alfredo M. Angeles-Boza
- Department of Chemistry, Institute of Materials Science, University of Connecticut, Storrs, CT, United States
| |
Collapse
|
20
|
Tavares M, Kozak M, Balola A, Coutinho CP, Godinho CP, Hassan AA, Cooper VS, Sá-Correia I. Adaptation and Survival of Burkholderia cepacia and B. contaminans During Long-Term Incubation in Saline Solutions Containing Benzalkonium Chloride. Front Bioeng Biotechnol 2020; 8:630. [PMID: 32714902 PMCID: PMC7344210 DOI: 10.3389/fbioe.2020.00630] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 05/22/2020] [Indexed: 01/28/2023] Open
Abstract
The Burkholderia cepacia complex (Bcc) is a group of opportunistic pathogenic bacteria with a remarkable metabolic capacity and broad genotypic/phenotypic plasticity, allowing their adaptation to hostile conditions, including nutrient depleted solutions containing antimicrobial agents. Bcc bacteria are feared contaminants in pharmaceutical industries and cause nosocomial outbreaks, posing health threats to immunocompromised individuals and cystic fibrosis (CF) patients. In this study, the adaptation and survival of B. cepacia and B. contaminans isolates was investigated after long-term incubation in nutrient depleted saline solutions supplemented with increasing concentrations of the biocidal preservative benzalkonium chloride (BZK), recreating the storage conditions of pharmaceutical products. These epidemiologically related isolates were recovered from intrinsically contaminated saline solutions for nasal application and from two CF patients. Long-term incubation in saline solutions containing BZK led to the development of bacterial sub-populations that survived for at least 16 months, despite an initial 2-3 log decrease in viability, displaying a progressive dose-dependent decrease of colony and cell size, including the appearance of small colony variants (SCVs). Bacterial colonies lost pigmentation, changed the morphotype from rough to smooth and produced more spherical cells during extended incubation with BZK. The development of macroscopically visible cellular aggregates, rich in polysaccharide and harboring viable cells in their interior was triggered by BZK. The existence of a metabolic pathway for BZK degradation was confirmed through genome analysis. This study reveals mechanisms underlying the prevalence of Bcc bacteria as contaminants of pharmaceutical products containing BZK, which often lead to false-negative results during quality control and routine testing.
Collapse
Affiliation(s)
- Mariana Tavares
- iBB - Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.,Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Mariya Kozak
- iBB - Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.,Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Alexandra Balola
- iBB - Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.,Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Carla P Coutinho
- iBB - Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Cláudia P Godinho
- iBB - Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - A Amir Hassan
- iBB - Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.,Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Vaughn S Cooper
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Isabel Sá-Correia
- iBB - Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal.,Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| |
Collapse
|
21
|
Bernardy EE, Petit RA, Raghuram V, Alexander AM, Read TD, Goldberg JB. Genotypic and Phenotypic Diversity of Staphylococcus aureus Isolates from Cystic Fibrosis Patient Lung Infections and Their Interactions with Pseudomonas aeruginosa. mBio 2020; 11. [PMID: 32576671 DOI: 10.31234/osf.io/9whp4] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023] Open
Abstract
Staphylococcus aureus has recently overtaken Pseudomonas aeruginosa as the most commonly recognized bacterial pathogen that infects the respiratory tracts of individuals with the genetic disease cystic fibrosis (CF) in the United States. Most studies of S. aureus in CF patient lung infections have focused on a few isolates, often exclusively laboratory-adapted strains, and how they are killed by P. aeruginosa Less is known about the diversity of S. aureus CF patient lung isolates in terms of both their virulence and their interaction with P. aeruginosa To begin to address this gap, we recently sequenced 64 clinical S. aureus isolates and a reference isolate, JE2. Here, we analyzed the antibiotic resistance genotypes, sequence types, clonal complexes, spa types, agr types, and presence/absence of other known virulence factor genes of these isolates. We hypothesized that virulence phenotypes of S. aureus, namely, toxin production and the mucoid phenotype, would be lost in these isolates due to adaptation in the CF patient lung. In contrast to these expectations, we found that most isolates can lyse both rabbit and sheep blood (67.7%) and produce polysaccharide (69.2%), suggesting that these phenotypes were not lost during adaptation to the CF lung. We also identified three distinct phenotypic groups of S. aureus based on their survival in the presence of nonmucoid P. aeruginosa laboratory strain PAO1 and its mucoid derivative. Altogether, our work provides greater insight into the diversity of S. aureus isolates from CF patients, specifically the distribution of important virulence factors and their interaction with P. aeruginosa, all of which have implications in patient health.IMPORTANCEStaphylococcus aureus is now the most frequently detected recognized pathogen in the lungs of individuals who have cystic fibrosis (CF) in the United States, followed closely by Pseudomonas aeruginosa When these pathogens are found to coinfect the CF lung, patients have a significantly worse prognosis. While P. aeruginosa has been rigorously studied in the context of bacterial pathogenesis in CF, less is known about S. aureus Here, we present an in-depth study of 64 S. aureus clinical isolates from CF patients, for which we investigated genetic diversity utilizing whole-genome sequencing, virulence phenotypes, and interactions with P. aeruginosa We found that S. aureus isolated from CF lungs are phylogenetically diverse; most retain known virulence factors and vary in their interactions with P. aeruginosa (i.e., they range from being highly sensitive to P. aeruginosa to completely tolerant to it). Deepening our understanding of how S. aureus responds to its environment and other microbes in the CF lung will enable future development of effective treatments and preventative measures against these formidable infections.
Collapse
Affiliation(s)
- Eryn E Bernardy
- Department of Pediatrics, Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis, and Sleep, Emory University, Atlanta, Georgia, USA
- Emory-Children's Center for Cystic Fibrosis Research, Children's Healthcare of Atlanta, Atlanta, Georgia, USA
| | - Robert A Petit
- Department of Medicine, Division of Infectious Diseases, Emory University, Atlanta, Georgia, USA
| | - Vishnu Raghuram
- Department of Pediatrics, Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis, and Sleep, Emory University, Atlanta, Georgia, USA
- Microbiology and Molecular Genetics Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, USA
| | - Ashley M Alexander
- Department of Pediatrics, Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis, and Sleep, Emory University, Atlanta, Georgia, USA
- Population Biology, Ecology, and Evolution Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, USA
| | - Timothy D Read
- Department of Medicine, Division of Infectious Diseases, Emory University, Atlanta, Georgia, USA
- Population Biology, Ecology, and Evolution Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, USA
| | - Joanna B Goldberg
- Department of Pediatrics, Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis, and Sleep, Emory University, Atlanta, Georgia, USA
- Emory-Children's Center for Cystic Fibrosis Research, Children's Healthcare of Atlanta, Atlanta, Georgia, USA
- Population Biology, Ecology, and Evolution Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, USA
| |
Collapse
|
22
|
Bernardy EE, Petit RA, Raghuram V, Alexander AM, Read TD, Goldberg JB. Genotypic and Phenotypic Diversity of Staphylococcus aureus Isolates from Cystic Fibrosis Patient Lung Infections and Their Interactions with Pseudomonas aeruginosa. mBio 2020; 11:mBio.00735-20. [PMID: 32576671 PMCID: PMC7315118 DOI: 10.1128/mbio.00735-20] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Staphylococcus aureus has recently overtaken Pseudomonas aeruginosa as the most commonly recognized bacterial pathogen that infects the respiratory tracts of individuals with the genetic disease cystic fibrosis (CF) in the United States. Most studies of S. aureus in CF patient lung infections have focused on a few isolates, often exclusively laboratory-adapted strains, and how they are killed by P. aeruginosa Less is known about the diversity of S. aureus CF patient lung isolates in terms of both their virulence and their interaction with P. aeruginosa To begin to address this gap, we recently sequenced 64 clinical S. aureus isolates and a reference isolate, JE2. Here, we analyzed the antibiotic resistance genotypes, sequence types, clonal complexes, spa types, agr types, and presence/absence of other known virulence factor genes of these isolates. We hypothesized that virulence phenotypes of S. aureus, namely, toxin production and the mucoid phenotype, would be lost in these isolates due to adaptation in the CF patient lung. In contrast to these expectations, we found that most isolates can lyse both rabbit and sheep blood (67.7%) and produce polysaccharide (69.2%), suggesting that these phenotypes were not lost during adaptation to the CF lung. We also identified three distinct phenotypic groups of S. aureus based on their survival in the presence of nonmucoid P. aeruginosa laboratory strain PAO1 and its mucoid derivative. Altogether, our work provides greater insight into the diversity of S. aureus isolates from CF patients, specifically the distribution of important virulence factors and their interaction with P. aeruginosa, all of which have implications in patient health.IMPORTANCEStaphylococcus aureus is now the most frequently detected recognized pathogen in the lungs of individuals who have cystic fibrosis (CF) in the United States, followed closely by Pseudomonas aeruginosa When these pathogens are found to coinfect the CF lung, patients have a significantly worse prognosis. While P. aeruginosa has been rigorously studied in the context of bacterial pathogenesis in CF, less is known about S. aureus Here, we present an in-depth study of 64 S. aureus clinical isolates from CF patients, for which we investigated genetic diversity utilizing whole-genome sequencing, virulence phenotypes, and interactions with P. aeruginosa We found that S. aureus isolated from CF lungs are phylogenetically diverse; most retain known virulence factors and vary in their interactions with P. aeruginosa (i.e., they range from being highly sensitive to P. aeruginosa to completely tolerant to it). Deepening our understanding of how S. aureus responds to its environment and other microbes in the CF lung will enable future development of effective treatments and preventative measures against these formidable infections.
Collapse
Affiliation(s)
- Eryn E Bernardy
- Department of Pediatrics, Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis, and Sleep, Emory University, Atlanta, Georgia, USA
- Emory-Children's Center for Cystic Fibrosis Research, Children's Healthcare of Atlanta, Atlanta, Georgia, USA
| | - Robert A Petit
- Department of Medicine, Division of Infectious Diseases, Emory University, Atlanta, Georgia, USA
| | - Vishnu Raghuram
- Department of Pediatrics, Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis, and Sleep, Emory University, Atlanta, Georgia, USA
- Microbiology and Molecular Genetics Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, USA
| | - Ashley M Alexander
- Department of Pediatrics, Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis, and Sleep, Emory University, Atlanta, Georgia, USA
- Population Biology, Ecology, and Evolution Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, USA
| | - Timothy D Read
- Department of Medicine, Division of Infectious Diseases, Emory University, Atlanta, Georgia, USA
- Population Biology, Ecology, and Evolution Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, USA
| | - Joanna B Goldberg
- Department of Pediatrics, Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis, and Sleep, Emory University, Atlanta, Georgia, USA
- Emory-Children's Center for Cystic Fibrosis Research, Children's Healthcare of Atlanta, Atlanta, Georgia, USA
- Population Biology, Ecology, and Evolution Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, USA
| |
Collapse
|
23
|
Lacoma A, Usón L, Mendoza G, Sebastián V, Garcia-Garcia E, Muriel-Moreno B, Domínguez J, Arruebo M, Prat C. Novel intracellular antibiotic delivery system against Staphylococcus aureus: cloxacillin-loaded poly(d,l-lactide-co-glycolide) acid nanoparticles. Nanomedicine (Lond) 2020; 15:1189-1203. [DOI: 10.2217/nnm-2019-0371] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Aim: First, to compare in vitro minimum inhibitory concentrations (MIC) of free cloxacillin and cloxacillin-containing nanoparticles (NP) against methicillin-susceptible (MSSA) and resistant Staphylococcus aureus (MRSA) and second, to assess NP antimicrobial activity against intracellular S. aureus. Methods: Poly(d,l-lactide-co-glycolide) acid (PLGA)-NP were loaded with cloxacillin and physico-chemically characterized. MICs were determined for reference strains Newman-(MSSA) and USA300-(MRSA). Murine alveolar macrophages were infected, and bacterial intracellular survival was assessed after incubating with free-cloxacillin or PLGA-cloxacillin-NP. Results & conclusion: For both isolates, MICs for antibiotic-loaded-NP were lower than those obtained with free cloxacillin, indicating that the drug encapsulation improves antimicrobial activity. A sustained antibiotic release was demonstrated when using the PLGA-cloxacillin-NP. When considering the lowest concentrations, the use of drug-loaded NP enabled a higher reduction of intracellular bacterial load.
Collapse
Affiliation(s)
- Alicia Lacoma
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Fundació Institut d’Investigació en Ciències de la Salut GermansTrias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
- CIBER Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, Spain
| | - Laura Usón
- Institute of Nanoscience of Aragon (INA), Department of Chemical Engineering & Environmental Technologies, University of Zaragoza & Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, 50018, Zaragoza, Spain
- CIBER Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Instituto de Salud Carlos III, Spain
| | - Gracia Mendoza
- Institute of Nanoscience of Aragon (INA), Department of Chemical Engineering & Environmental Technologies, University of Zaragoza & Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, 50018, Zaragoza, Spain
- CIBER Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Instituto de Salud Carlos III, Spain
| | - Victor Sebastián
- Institute of Nanoscience of Aragon (INA), Department of Chemical Engineering & Environmental Technologies, University of Zaragoza & Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, 50018, Zaragoza, Spain
- CIBER Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Instituto de Salud Carlos III, Spain
| | - Esther Garcia-Garcia
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Fundació Institut d’Investigació en Ciències de la Salut GermansTrias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Beatriz Muriel-Moreno
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Fundació Institut d’Investigació en Ciències de la Salut GermansTrias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Jose Domínguez
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Fundació Institut d’Investigació en Ciències de la Salut GermansTrias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
- CIBER Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, Spain
| | - Manuel Arruebo
- Institute of Nanoscience of Aragon (INA), Department of Chemical Engineering & Environmental Technologies, University of Zaragoza & Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, 50018, Zaragoza, Spain
- CIBER Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Instituto de Salud Carlos III, Spain
| | - Cristina Prat
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Fundació Institut d’Investigació en Ciències de la Salut GermansTrias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
- CIBER Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, Spain
- Julius Centre for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| |
Collapse
|
24
|
Côté-Gravel J, Brouillette E, Malouin F. Vaccination with a live-attenuated small-colony variant improves the humoral and cell-mediated responses against Staphylococcus aureus. PLoS One 2019; 14:e0227109. [PMID: 31881064 PMCID: PMC6934294 DOI: 10.1371/journal.pone.0227109] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 12/12/2019] [Indexed: 02/07/2023] Open
Abstract
Staphylococcus aureus is known to produce persistent and chronic infections in both humans and animals. It is recognized that small-colony variants (SCVs), which produce higher levels of biofilm and that are capable of intracellular persistence, contribute to the chronicity or recurrence of infections and that this phenotype is inherent to the pathogenesis process. Prevention of S. aureus infections through vaccination has not yet met with considerable success. Some of the current vaccine formulations for S. aureus bovine mastitis consist of inactivated S. aureus bacteria, sometimes combined to E. coli J5. As such, the stimulation of cell-mediated immunity by these vaccines might not be optimal. With this in mind, we recently engineered a genetically stable double mutant SCV (ΔvraGΔhemB), which was highly attenuated in a mastitis model of infection. The present work describes the immune responses elicited in mice by various experimental vaccine compositions including the live-attenuated SCV double mutant and its inactivated form, combined or not with inactivated E. coli J5. The live-attenuated SCV was found to provoke a strong and balanced humoral response in immunized mice, as well as strong proliferation of ex-vivo stimulated splenocytes isolated from these animals. These splenocytes were also found to release high concentration of IL-17 and IFN-γ when compared to every other vaccination formulation. Inversely, the inactivated whole-cell vaccine, alone or in combination with the E. coli J5 bacterin, elicited lower antibody titers and failed to induce Th1 or Th17 cell-mediated responses in the splenocyte proliferation assay. Our results suggest that live-attenuated SCVs can trigger host immunity differently than inactivated bacteria and could represent a suitable vector for inducing strong humoral and cell-mediated immune responses, which are crucial for protection. This could represent an important improvement over existing vaccine formulations for preventing S. aureus bovine mastitis and other infections caused by this pathogen.
Collapse
Affiliation(s)
- Julie Côté-Gravel
- Centre d’étude et de Valorisation de la Diversité Microbienne (CEVDM), Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, Canada
| | - Eric Brouillette
- Centre d’étude et de Valorisation de la Diversité Microbienne (CEVDM), Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, Canada
| | - François Malouin
- Centre d’étude et de Valorisation de la Diversité Microbienne (CEVDM), Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, Canada
- * E-mail:
| |
Collapse
|
25
|
Wolter DJ, Onchiri FM, Emerson J, Precit MR, Lee M, McNamara S, Nay L, Blackledge M, Uluer A, Orenstein DM, Mann M, Hoover W, Gibson RL, Burns JL, Hoffman LR. Prevalence and clinical associations of Staphylococcus aureus small-colony variant respiratory infection in children with cystic fibrosis (SCVSA): a multicentre, observational study. THE LANCET RESPIRATORY MEDICINE 2019; 7:1027-1038. [PMID: 31727592 DOI: 10.1016/s2213-2600(19)30365-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 08/08/2019] [Accepted: 09/05/2019] [Indexed: 10/25/2022]
Abstract
BACKGROUND Staphylococcus aureus is the bacterium cultured most often from respiratory secretions of people with cystic fibrosis. Both meticillin-susceptible S aureus and meticillin-resistant S aureus (MRSA) can adapt to form slow-growing, antibiotic-resistant isolates known as small-colony variants that are not routinely identified by clinical laboratories. We aimed to determine the prevalence and clinical significance of S aureus small-colony variants and their subtypes among children with cystic fibrosis. METHODS The Small Colony Variant Staphylococcus aureus (SCVSA) study was a 2-year longitudinal study of children aged 6-16 years at five US cystic fibrosis centres, using culture methods sensitive for small-colony variants. Children were eligible if they had a documented diagnosis of cystic fibrosis and a minimum of two cystic fibrosis clinic visits and two respiratory cultures in the previous 12 months at enrolment. Participants attended clinic visits quarterly, at which respiratory tract samples were taken and measures of lung function (percentage of predicted forced expiratory volume in 1 s [FEV1] and frequency of respiratory exacerbations) were recorded. We determined the prevalence of small-colony variants and their subtypes, and assessed their independent associations with lung function and respiratory exacerbations using linear mixed-effects and generalised estimating equation logistic regression models. Analyses included both univariate models (unadjusted) and multivariate models that adjusted for potential confounders, including age, sex, race, baseline microbiology, treatment with CFTR modulator, and CTFR genotype. FINDINGS Between July 1, 2014, and May 26, 2015, we enrolled 230 children. Participants were followed-up for 2 years, with a mean of 6·4 visits (SD 1·14) per participant (range 2-9 visits) and a mean interval between visits of 3·94 months (SD 1·77). Across the 2-year period, S aureus small-colony variants were detected in 64 (28%) participants. Most (103 [56%] of 185) of the small-colony variants detected in these participants were thymidine dependent. Children with small-colony variants had significantly lower mean percentage of predicted FEV1 at baseline than did children without small-colony variants (85·5 [SD 19] vs 92·4 [SD 18·6]; p=0·0145). Small-colony variants were associated with significantly lower percentage of predicted FEV1 throughout the study in regression models, both in univariate analyses (regression coefficient -7·07, 95% CI -12·20 to -1·95; p=0·0068) and in multivariate analyses adjusting for potential confounders (-5·50, -10·51 to -0·48; p=0·0316). Small colony variants of the thymidine-dependent subtype had the strongest association with lung function in multivariate regression models (regression coefficient -10·49, -17·25 to -3·73; p=0·0024). Compared with children without small-colony variants, those with small-colony variants had significantly increased odds of respiratory exacerbations in univariate analyses (odds ratio 1·73, 95% CI 1·19 to 2·52; p=0·0045). Children with thymidine-dependent small-colony variants had significantly increased odds of respiratory exacerbations (2·81, 1·69-4·67; p=0·0001), even after adjusting for age, sex, race, genotype, CFTR modulator, P aeruginosa culture status, and baseline percentage of predicted FEV1 (2·17, 1·33-3·57; p=0·0021), whereas those with non-thymidine-dependent small-colony variants did not. In multivariate models including small-colony variants and MRSA status, P aeruginosa was not independently associated with lung function (regression coefficient -4·77, 95% CI -10·36 to 0·83; p=0·10) and was associated with reduced odds of exacerbations (0·54, 0·36 to 0·81; p=0·0028). Only the small-colony variant form of MRSA was associated with reduced lung function (-8·44, -16·15 to -0·72; p=0·0318) and increased odds of exacerbations (2·15, 1·24 to 3·71; p=0·0061). INTERPRETATION Infection with small-colony variants, and particularly thymidine-dependent small-colony variants, was common in a multicentre paediatric population with cystic fibrosis and associated with reduced lung function and increased risk of respiratory exacerbations. The adoption of small-colony variant identification and subtyping methods by clinical laboratories, and the inclusion of small-colony variant prevalence data in cystic fibrosis registries, should be considered for ongoing surveillance and study. FUNDING The Cystic Fibrosis Foundation and the National Institutes of Health.
Collapse
Affiliation(s)
- Daniel J Wolter
- Department of Pediatrics and Department of Microbiology, University of Washington, Seattle, WA, USA; Department of Pediatrics, Seattle Children's Hospital, Seattle, WA, USA
| | | | - Julia Emerson
- Department of Pediatrics and Department of Microbiology, University of Washington, Seattle, WA, USA; Department of Pediatrics, Seattle Children's Hospital, Seattle, WA, USA
| | - Mimi R Precit
- Department of Pediatrics and Department of Microbiology, University of Washington, Seattle, WA, USA
| | - Michael Lee
- Department of Pediatrics and Department of Microbiology, University of Washington, Seattle, WA, USA
| | - Sharon McNamara
- Department of Pediatrics, Seattle Children's Hospital, Seattle, WA, USA
| | - Laura Nay
- Department of Pediatrics, Seattle Children's Hospital, Seattle, WA, USA
| | | | - Ahmet Uluer
- Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA; Department of Pediatrics, Brigham and Women's Hospital, Boston, MA, USA
| | - David M Orenstein
- Department of Pediatrics, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michelle Mann
- Department of Pediatrics, Texas Children's Hospital, Houston, TX, USA
| | - Wynton Hoover
- Department of Pediatrics, University of Alabama, Tuscaloosa, AL, USA
| | - Ronald L Gibson
- Department of Pediatrics, Seattle Children's Hospital, Seattle, WA, USA
| | - Jane L Burns
- Department of Pediatrics and Department of Microbiology, University of Washington, Seattle, WA, USA; Department of Pediatrics, Seattle Children's Hospital, Seattle, WA, USA
| | - Lucas R Hoffman
- Department of Pediatrics and Department of Microbiology, University of Washington, Seattle, WA, USA; Department of Pediatrics, Seattle Children's Hospital, Seattle, WA, USA.
| | | |
Collapse
|
26
|
Garbacz K, Kwapisz E, Wierzbowska M. Denture stomatitis associated with small-colony variants of Staphylococcus aureus: a case report. BMC Oral Health 2019; 19:219. [PMID: 31604449 PMCID: PMC6788114 DOI: 10.1186/s12903-019-0910-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 09/13/2019] [Indexed: 11/23/2022] Open
Abstract
Background The small-colony variants (SCVs) of Staphylococcus aureus were isolated from persistent and recurrent infections, especially after placement of medical devices having direct contact with human tissues. The emergence of SCVs is a survival strategy of S. aureus which enables them to hide inside host’s cells and induces a less severe immune response than to wild-type S. aureus. However, contrary to other medical devices, dental prosthesis as a surface potentially colonized by SCVs of S. aureus has not been examined thus far. We reported the first case of SCVs - S. aureus infection in denture wearer. Case presentation A 62-year-old woman with a complete removable acrylic denture presented extensive elevated erythematous lesions on the palate, compatible with denture stomatitis. The patient had a history of arterial hypertension, cigarette smoking and wearing denture at night. The fungal colonies, identified as Candida albicans, were cultured on Sabouraud agar. From three swabs (from hard palate mucosa, denture surface and angular cheilitis lesions) were cultured of pinpoint, clear, non-pigmented, and non-haemolytic colonies on Columbia agar. The small colonies turned out to be Gram-positive cocci, catalase-, Pastorex Staph Plus -, and clumping factor-positive, and oxidase-negative. Suspected phenotypically SCVs forms were definitively identified as S. aureus based on PCR amplification of species specific nuc and coa genes. Methicillin-resistance was verified by mecA gene detection. The isolates turned out to be susceptible to methicillin (MSSA) and resistant to gentamicin. The isolate was identified as menadione-auxotrophic variant. Conclusions This case demonstrated that oral cavity in denture wearers may be a reservoir of small-colony variants of S. aureus, besides C. albicans. The prevalence of these bacteria and their role in the pathogenesis of oral diseases are not understood. Due to problems with their detection and identification, the true prevalence of oral SCVs may be underestimated.
Collapse
Affiliation(s)
- Katarzyna Garbacz
- Department of Oral Microbiology, Faculty of Medicine, Medical University of Gdansk, 25 Dębowa St, 80-204, Gdansk, Poland.
| | - Ewa Kwapisz
- Department of Oral Microbiology, Faculty of Medicine, Medical University of Gdansk, 25 Dębowa St, 80-204, Gdansk, Poland
| | - Maria Wierzbowska
- Department of Oral Microbiology, Faculty of Medicine, Medical University of Gdansk, 25 Dębowa St, 80-204, Gdansk, Poland
| |
Collapse
|
27
|
Hingston PA, Truelstrup Hansen L, Pombert JF, Wang S. Characterization of Listeria monocytogenes enhanced cold-tolerance variants isolated during prolonged cold storage. Int J Food Microbiol 2019; 306:108262. [PMID: 31362162 DOI: 10.1016/j.ijfoodmicro.2019.108262] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 05/04/2019] [Accepted: 07/07/2019] [Indexed: 11/25/2022]
Abstract
In this study, we show that growth and prolonged storage of Listeria monocytogenes at 4 °C can promote the selection of variants with enhanced cold and heat tolerance. Enhanced cold-tolerance (ECT) variants (n = 12) were successfully isolated from a strain with impaired cold growth abilities following 84 days of storage at 4 °C in brain heart infusion broth (BHIB). Whole genome sequencing, membrane fatty acid analysis, and stress tolerance profiling were performed on the parent strain and two ECT variants: one displaying regular-sized colonies and the other displaying small colonies when grown at 37 °C on BHI agar. Under cold stress conditions, the parent strain exhibited an impaired ability to produce branched-chain fatty acids which are known to be important for cold adaptation in L.monocytogenes. The ECT variants were able to overcome this limitation, a finding which is hypothesized to be associated with the identification of two independent single-nucleotide polymorphisms in genes encoding subunits of acetyl-coA carboxylase, an enzyme critical for fatty acid biosynthesis. While the ECT phenotype was not found to be associated with improved salt (BHIB + 6% NaCl, 25 °C), acid (BHIB pH 5, 25 °C) or desiccation (33% RH, 20 °C) tolerance, the small-colony variant exhibited significantly (p < 0.05) enhanced heat tolerance at 52 °C in buffered peptone water compared to the parent strain and the other variant. The results from this study demonstrate that the continuous use of refrigeration along the food-supply chain has the potential to select for L.monocytogenes variants with enhanced cold and heat tolerance, highlighting the impact that microbial intervention strategies can have on the evolution of bacterial strains and likewise, food safety.
Collapse
Affiliation(s)
- Patricia A Hingston
- Food, Nutrition and Health, The University of British Columbia, Vancouver, British Columbia, Canada
| | | | | | - Siyun Wang
- Food, Nutrition and Health, The University of British Columbia, Vancouver, British Columbia, Canada.
| |
Collapse
|
28
|
Activity of Antibiotics against Staphylococcus aureus in an In Vitro Model of Biofilms in the Context of Cystic Fibrosis: Influence of the Culture Medium. Antimicrob Agents Chemother 2019; 63:AAC.00602-19. [PMID: 31036685 DOI: 10.1128/aac.00602-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 04/20/2019] [Indexed: 01/27/2023] Open
Abstract
Staphylococcus aureus is a highly prevalent pathogen in the respiratory tract of young patients with cystic fibrosis (CF) and causes biofilm-related infections. Here, we set up an in vitro model of a biofilm grown in Trypticase soy broth supplemented with glucose and NaCl (TGN) or in artificial sputum medium (ASM) and used it to evaluate on a pharmacodynamic basis the activity of antibiotics used in CF patients and active on staphylococci (meropenem, vancomycin, azithromycin, linezolid, rifampin, ciprofloxacin, tobramycin). Rheological studies showed that ASM was more elastic than viscous, as was also observed for sputa from CF patients, with elastic and viscous moduli being, respectively, similar to and slightly lower than those of CF sputa. Biofilms formed by methicillin-sensitive S. aureus strain ATCC 25923 and methicillin-resistant S. aureus strain ATCC 33591 reached maturity after 24 h, with biomass (measured by crystal violet staining) and metabolic activity (assessed by following resazurin metabolization) being lower in ASM than in TGN and viability (assessed by bacterial counts) being similar in both media. Full concentration-response curves of antibiotics obtained after 24 h of incubation of biofilms showed that all antibiotics were drastically less potent and less efficient in ASM than in TGN toward viability, metabolic activity, and biomass. Tobramycin selected for small-colony variants, specifically in biofilms grown in ASM; the auxotrophism of these variants could not be established. These data highlight the major influence exerted by the culture medium on S. aureus responsiveness to antibiotics in biofilms. The use of ASM may help to determine effective drug concentrations or to evaluate new therapeutic options against biofilms in CF patients.
Collapse
|
29
|
Kittinger C, Toplitsch D, Folli B, Masoud Landgraf L, Zarfel G. Phenotypic Stability of Staphylococcus Aureus Small Colony Variants (SCV) Isolates from Cystic Fibrosis (CF) Patients. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16111940. [PMID: 31159295 PMCID: PMC6603916 DOI: 10.3390/ijerph16111940] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 05/28/2019] [Accepted: 05/30/2019] [Indexed: 12/23/2022]
Abstract
One of the most interesting features of Staphylococcus aureus is its ability to switch to a small colony variant (SCV). This switch allows the pathogen to survive periods of antibiotic treatment or pressure from the immune system of the host and further enables it to start the infection once again after the environmental stress declines. However, so far only little is known about this reversion back to the more virulent wild type phenotype. Therefore, this study aimed to analyze the frequency of reversion to the wild type phenotype of thymidine auxotroph S. aureus SCV isolates (TD-SCVs) obtained from patients with cystic fibrosis (CF). With the use of single cell starting cultures, the occurrence of the thymidine prototroph revertants was monitored. The underlying mutational cause of the SCVs and subsequent revertants were analyzed by sequencing the gene coding for thymidylate synthase (ThyA), whose mutations are known to produce thymidine auxotroph S. aureus SCV. In our study, the underlying mutational cause for the switch to the TD-SCV phenotype was primarily point mutations. Out of twelve isolates, seven isolates showed an occurrence of revertants with a frequency ranging from 90.06% to 0.16%. This high variability in the frequency of reversion to the wild type was not expected. However, this variability in the frequency of reversion may also be the key to successful re-infection of the host. Sometimes quick reversion to the wild type proves necessary for survival, whereas other times, staying hidden for a bit longer leads to success in re-colonization of the host.
Collapse
Affiliation(s)
- Clemens Kittinger
- Diagnostic and Research Center for Molecular BioMedicine, Medical University of Graz, 8010 Graz, Austria.
| | - Daniela Toplitsch
- Diagnostic and Research Center for Molecular BioMedicine, Medical University of Graz, 8010 Graz, Austria.
| | - Bettina Folli
- Diagnostic and Research Center for Molecular BioMedicine, Medical University of Graz, 8010 Graz, Austria.
| | - Lilian Masoud Landgraf
- Diagnostic and Research Center for Molecular BioMedicine, Medical University of Graz, 8010 Graz, Austria.
| | - Gernot Zarfel
- Diagnostic and Research Center for Molecular BioMedicine, Medical University of Graz, 8010 Graz, Austria.
| |
Collapse
|
30
|
Perez K, Patel R. Staphylococcusepidermidis Small-Colony Variants Are Induced by Low pH and Their Frequency Reduced by Lysosomal Alkalinization. J Infect Dis 2019; 215:488-490. [PMID: 27974434 DOI: 10.1093/infdis/jiw503] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 10/13/2016] [Indexed: 11/12/2022] Open
Affiliation(s)
| | - Robin Patel
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, and.,Division of Infectious Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| |
Collapse
|
31
|
Proctor R. Respiration and Small Colony Variants of Staphylococcus aureus. Microbiol Spectr 2019; 7:10.1128/microbiolspec.gpp3-0069-2019. [PMID: 31198131 PMCID: PMC11257146 DOI: 10.1128/microbiolspec.gpp3-0069-2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Indexed: 12/16/2022] Open
Abstract
Respiratory mutants, both naturally occurring and genetically constructed, have taught us about the importance of metabolism in influencing virulence factor production, persistence, and antibiotic resistance. As we learn more about small colony variants, we find that Staphylococcus aureus has many pathways to produce small colony variants, although the respiratory variants are the best described clinically and in the laboratory.
Collapse
Affiliation(s)
- Richard Proctor
- Department of Medical Microbiology and Immunology University of Wisconsin School of Medicine and Public Health Madison, WI 53705
| |
Collapse
|
32
|
Zhang P, Wright JA, Tymon A, Nair SP. Bicarbonate induces high-level resistance to the human antimicrobial peptide LL-37 in Staphylococcus aureus small colony variants. J Antimicrob Chemother 2019; 73:615-619. [PMID: 29211886 PMCID: PMC5890704 DOI: 10.1093/jac/dkx433] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 10/25/2017] [Indexed: 01/29/2023] Open
Abstract
Objectives Staphylococcus aureus small colony variants (SCVs) cause persistent infections and are resistant to cationic antibiotics. Antimicrobial peptides (AMPs) have been suggested as promising alternatives for treating antibiotic-resistant bacteria. We investigated the capacity of the human cationic AMP LL-37 to kill SCVs in the presence of physiological concentrations of bicarbonate, which are reported to alter bacterial membrane permeability and change resistance of bacteria to AMPs. Methods MBCs of LL-37 for S. aureus SCVs with mutations in different genes in the presence and absence of bicarbonate were determined. Results In the absence of bicarbonate, SCVs of S. aureus strains LS-1 and 8325-4 had the same level of resistance to LL-37 as the parental strain (8 mg/L). In the presence of bicarbonate, hemB, menD and aroD SCVs of LS-1 had high-level resistance to LL-37 (≥128 mg/L) compared with the parental strain (16 mg/L). However, only the aroD SCV of strain 8324-5 showed high-level resistance. 8325-4 harbours mutations in two genes, tcaR and rsbU, which are involved in antimicrobial sensing and the stress response, respectively. When rsbU was repaired in 8325-4 it displayed high-level resistance to LL-37 in the presence of bicarbonate. This phenotype was lost when tcaR was also repaired, demonstrating that RsbU and TcaR are involved in LL-37 resistance in the presence of bicarbonate Conclusions S. aureus SCVs would be resistant to high concentrations of LL-37 in niches where there are physiological concentrations of bicarbonate and therefore this AMP may not be effective in combating SCVs.
Collapse
Affiliation(s)
- Ping Zhang
- Department of Microbial Diseases, UCL Eastman Dental Institute, 256 Gray's Inn Road, London WC1X 8LD, UK
| | - John A Wright
- Immunology Catalyst, GSK, Stevenage, Hertfordshire, UK
| | - Anna Tymon
- Department of Microbial Diseases, UCL Eastman Dental Institute, 256 Gray's Inn Road, London WC1X 8LD, UK
| | - Sean P Nair
- Department of Microbial Diseases, UCL Eastman Dental Institute, 256 Gray's Inn Road, London WC1X 8LD, UK
| |
Collapse
|
33
|
Melenotte C, Drancourt M, Gorvel JP, Mège JL, Raoult D. Post-bacterial infection chronic fatigue syndrome is not a latent infection. Med Mal Infect 2019; 49:140-149. [DOI: 10.1016/j.medmal.2019.01.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 01/15/2019] [Indexed: 01/20/2023]
|
34
|
Zhou K, Li C, Chen D, Pan Y, Tao Y, Qu W, Liu Z, Wang X, Xie S. A review on nanosystems as an effective approach against infections of Staphylococcus aureus. Int J Nanomedicine 2018; 13:7333-7347. [PMID: 30519018 PMCID: PMC6233487 DOI: 10.2147/ijn.s169935] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Staphylococcus aureus (S. aureus) is an important zoonotic bacteria and hazardous for the health of human beings and livestock globally. The characteristics like biofilm forming, facultative intracellular survival, and growing resistance of S. aureus pose a great challenge to its use in therapy. Nanoparticles are considered as a promising way to overcome the infections’ therapeutic problems caused by S. aureus. In this paper, the present progress and challenges of nanoparticles in the treatment of S. aureus infection are focused on stepwise. First, the survival and infection mechanism of S. aureus are analyzed. Second, the treatment challenges posed by S. aureus are provided, which is followed by the third step including the advantages of nanoparticles in improving the penetration and accumulation ability of their payload antibiotics into cell, inhibiting S. aureus biofilm formation, and enhancing the antibacterial activity against resistant isolates. Finally, the challenges and future perspective of nanoparticles for S. aureus infection therapy are introduced. This review will help the readers to realize that the nanosystems can effectively fight against the S. aureus infection by inhibiting biofilm formation, enhancing intracellular delivery, and improving activity against methicillin-resistant S. aureus and small colony variant phenotypes as well as aim to help researchers looking for more efficient nano-systems to combat the S. aureus infections.
Collapse
Affiliation(s)
- Kaixiang Zhou
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, China,
| | - Chao Li
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, China,
| | - Dongmei Chen
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, Hubei, China
| | - Yuanhu Pan
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, China,
| | - Yanfei Tao
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, Hubei, China
| | - Wei Qu
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, Hubei, China
| | - Zhenli Liu
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, Hubei, China
| | - Xiaofang Wang
- Animal Husbandry and Veterinary Institute of Hebei Province, Baoding, Hebei, China,
| | - Shuyu Xie
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, China,
| |
Collapse
|
35
|
Sousa AM, Monteiro R, Pereira MO. Unveiling the early events of Pseudomonas aeruginosa adaptation in cystic fibrosis airway environment using a long-term in vitro maintenance. Int J Med Microbiol 2018; 308:1053-1064. [PMID: 30377031 DOI: 10.1016/j.ijmm.2018.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 09/16/2018] [Accepted: 10/10/2018] [Indexed: 01/22/2023] Open
Abstract
Pseudomonas aeruginosa chronic infections are the major cause of high morbidity and mortality in cystic fibrosis (CF) patients due to the use of sophisticated mechanisms of adaptation, including clonal diversification into specialized CF-adapted phenotypes. In contrast to chronic infections, very little is known about what occurs after CF lungs colonization and at early infection stages. This study aims to investigate the early events of P. aeruginosa adaptation to CF environment, in particular, to inspect the occurrence of clonal diversification at early stages of infection development and its impact on antibiotherapy effectiveness. To mimic CF early infections, three P. aeruginosa strains were long-term grown in artificial sputum (ASM) over 10 days and phenotypic diversity verified through colony morphology characterization. Biofilm sub- and inhibitory concentrations of ciprofloxacin were applied to non- and diversified populations to evaluate antibiotic effectiveness on P. aeruginosa eradication. Our results demonstrated that clonal diversification might occur after ASM colonization and growth. However, this phenotypic diversification did not compromise ciprofloxacin efficacy in P. aeruginosa eradication since a biofilm minimal inhibitory dosage would be applied. The expected absence of mutators in P. aeruginosa populations led us to speculate that clonal diversification in the absence of ciprofloxacin treatments could be driven by niche specialization. Yet, biofilm sub-inhibitory concentrations of ciprofloxacin seemed to overlap niche specialization as "fitter" variants emerged, such as mucoid, small colony and pinpoint variants, known to be highly resistant to antibiotics. The pathogenic potential of all emergent colony morphotypes-associated bacteria, distinct from the wild-morphotypes, revealed that P. aeruginosa evolved to a non-swimming phenotype. Impaired swimming motility seemed to be one of the first evolutionary steps of P. aeruginosa in CF lungs that could pave the way for further adaptation steps including biofilm formation and progress to chronic infection. Based on our findings, impaired swimming motility seemed to be a candidate to disease marker of P. aeruginosa infection development. Despite our in vitro CF model represents a step forward towards in vivo scenario simulation and provided valuable insights about the early events, more and distinct P. aeruginosa strains should be studied to strengthen our results.
Collapse
Affiliation(s)
- Ana Margarida Sousa
- CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Rosana Monteiro
- CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Maria Olívia Pereira
- CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
| |
Collapse
|
36
|
Perez K, Patel R. Survival of Staphylococcus epidermidis in Fibroblasts and Osteoblasts. Infect Immun 2018; 86:e00237-18. [PMID: 30061380 PMCID: PMC6204734 DOI: 10.1128/iai.00237-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 07/20/2018] [Indexed: 12/26/2022] Open
Abstract
Staphylococcus epidermidis is a leading cause of infections associated with indwelling medical devices, including prosthetic joint infection. While biofilm formation is assumed to be the main mechanism underlying the chronic infections S. epidermidis causes, we hypothesized that S. epidermidis also evades immune killing, contributing to its pathogenesis. Here, we show that prosthetic joint-associated S. epidermidis isolates can persist intracellularly within human fibroblasts and inside human and mouse osteoblasts. We also show that the intracellularly persisting bacteria reside primarily within acidic phagolysosomes and that over the course of infection, small-colony variants are selected for. Moreover, upon eukaryotic cell death, these bacteria, which can outlive their host, can escape into the extracellular environment, providing them an opportunity to form biofilms on implant surfaces at delayed time points in implant-associated infection. In summary, the acidic phagolysosomes of fibroblasts and osteoblasts serve as reservoirs for chronic or delayed S. epidermidis infection.
Collapse
Affiliation(s)
- Kimberly Perez
- Department of Immunology, Mayo Clinic, Rochester, Minnesota, USA
| | - Robin Patel
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
- Division of Infectious Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA
| |
Collapse
|
37
|
Weaver AJ, Peters TR, Tripet B, Van Vuren A, Rakesh, Lee RE, Copié V, Teintze M. Exposure of Methicillin-Resistant Staphylococcus aureus to Low Levels of the Antibacterial THAM-3ΦG Generates a Small Colony Drug-Resistant Phenotype. Sci Rep 2018; 8:9850. [PMID: 29959441 PMCID: PMC6026174 DOI: 10.1038/s41598-018-28283-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 06/20/2018] [Indexed: 12/18/2022] Open
Abstract
This study investigated resistance against trishexylaminomelamine trisphenylguanide (THAM-3ΦG), a novel antibacterial compound with selective microbicidal activity against Staphylococcus aureus. Resistance development was examined by culturing methicillin resistant S. aureus (MRSA) with sub-lethal doses of THAM-3ΦG. This quickly resulted in the formation of normal (WT) and small colonies (SC) of S. aureus exhibiting minimal inhibitory concentrations (MICs) 2× and 4× greater than the original MIC. Continuous cell passaging with increasing concentrations of THAM-3ΦG resulted in an exclusively SC phenotype with MIC >64 mg/L. Nuclear magnetic resonance (NMR)-based metabolomics and multivariate statistical analysis revealed three distinct metabolic profiles for THAM-3ΦG treated WT, untreated WT, and SC (both treated and untreated). The metabolome patterns of the SC sample groups match those reported for other small colony variants (SCV) of S. aureus. Supplementation of the SCV with menadione resulted in almost complete recovery of growth rate. This auxotrophism was corroborated by NMR analysis revealing the absence of menaquinone production in the SCV. In conclusion, MRSA rapidly acquires resistance to THAM-3ΦG through selection of a slow-growing menaquinone auxotroph. This study highlights the importance of evaluating and monitoring resistance to novel antibacterials during development.
Collapse
Affiliation(s)
- Alan J Weaver
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, Montana, United States of America
- Dental and Craniofacial Trauma Research and Tissue Regeneration Directorate, U.S. Army Institute of Surgical Research, JBSA Fort Sam Houston, Texas, United States of America
| | - Tami R Peters
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, Montana, United States of America
| | - Brian Tripet
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, Montana, United States of America
| | - Abigail Van Vuren
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, Montana, United States of America
| | - Rakesh
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America
| | - Richard E Lee
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America
| | - Valérie Copié
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, Montana, United States of America
| | - Martin Teintze
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, Montana, United States of America.
| |
Collapse
|
38
|
Hurley MN. Staphylococcus aureus in cystic fibrosis: problem bug or an innocent bystander? Breathe (Sheff) 2018; 14:87-90. [PMID: 29877519 PMCID: PMC5980475 DOI: 10.1183/20734735.014718] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Staphylococcus aureus in cystic fibrosis: problem bug or an innocent bystander? The jury requires more evidence http://ow.ly/HQjk30j3nmL.
Collapse
Affiliation(s)
- Matthew N. Hurley
- Paediatric Respiratory Medicine, Nottingham Children’s Hospital, Nottingham, UK
| |
Collapse
|
39
|
Sakatos A, Babunovic GH, Chase MR, Dills A, Leszyk J, Rosebrock T, Bryson B, Fortune SM. Posttranslational modification of a histone-like protein regulates phenotypic resistance to isoniazid in mycobacteria. SCIENCE ADVANCES 2018; 4:eaao1478. [PMID: 29732401 PMCID: PMC5931751 DOI: 10.1126/sciadv.aao1478] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 03/20/2018] [Indexed: 05/08/2023]
Abstract
There is increasing evidence that phenotypically drug-resistant bacteria may be important determinants of antibiotic treatment failure. Using high-throughput imaging, we defined distinct subpopulations of mycobacterial cells that exhibit heritable but semi-stable drug resistance. These subpopulations have distinct transcriptional signatures and growth characteristics at both bulk and single-cell levels, which are also heritable and semi-stable. We find that the mycobacterial histone-like protein HupB is required for the formation of these subpopulations. Using proteomic approaches, we further demonstrate that HupB is posttranslationally modified by lysine acetylation and lysine methylation. Mutation of a single posttranslational modification site specifically abolishes the formation of one of the drug-resistant subpopulations of cells, providing the first evidence in prokaryotes that posttranslational modification of a bacterial nucleoid-associated protein may epigenetically regulate cell state.
Collapse
Affiliation(s)
- Alexandra Sakatos
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Gregory H. Babunovic
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Michael R. Chase
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Alexander Dills
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - John Leszyk
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 02129, USA
| | - Tracy Rosebrock
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
- Stonehill College, North Easton, MA 02357, USA
| | - Bryan Bryson
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Sarah M. Fortune
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
- The Ragon Institute of Massachusetts General Hospital, Harvard, and Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Corresponding author.
| |
Collapse
|
40
|
Fatty Acid Supplementation Reverses the Small Colony Variant Phenotype in Triclosan-Adapted Staphylococcus aureus: Genetic, Proteomic and Phenotypic Analyses. Sci Rep 2018; 8:3876. [PMID: 29497096 PMCID: PMC5832852 DOI: 10.1038/s41598-018-21925-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 02/06/2018] [Indexed: 11/08/2022] Open
Abstract
Staphylococcus aureus can develop a small colony variant (SCV) phenotype in response to sub-lethal exposure to the biocide triclosan. In the current study, whole genome sequencing was performed and changes in virulence were investigated in five Staphylococcus aureus strains following repeated exposure to triclosan. Following exposure, 4/5 formed SCV and exhibited point mutations in the triclosan target gene fabI with 2/4 SCVs showing mutations in both fabI and fabD. The SCV phenotype was in all cases immediately reversed by nutritional supplementation with fatty acids or by repeated growth in the absence of triclosan, although fabI mutations persisted in 3/4 reverted SCVs. Virulence, determined using keratinocyte invasion and Galleria mellonella pathogenicity assays was significantly (p < 0.05) attenuated in 3/4 SCVs and in the non-SCV triclosan-adapted bacterium. Proteomic analysis revealed elevated FabI in 2/3 SCV and down-regulation in a protein associated with virulence in 1/3 SCV. In summary, attenuated keratinocyte invasion and larval virulence in triclosan-induced SCVs was associated with decreases in growth rate and virulence factor expression. Mutation occurred in fabI, which encodes the main triclosan target in all SCVs and the phenotype was reversed by fatty acid supplementation, demonstrating an association between fatty acid metabolism and triclosan-induced SCV.
Collapse
|
41
|
Magryś A, Bogut A, Kiełbus M, Olender A. The role of the PI3K/mTOR signaling pathway in Staphylococcus epidermidis small colony variants intracellular survival. Immunol Invest 2018; 47:251-263. [PMID: 29336620 DOI: 10.1080/08820139.2018.1423569] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The objective of this study was to analyze how Staphylococcus epidermidis SCV and WT strains manipulate the PI3K/Akt/mTOR signaling pathway. Six S. epidermidis strains with normal phenotype (WT) and six S. epidermidis strains with SCV phenotype were isolated in parallel from six patients with the prosthetic hip joint infections. THP-1 activated cells were incubated with or without PI3K inhibitor-wortmannin or with mTOR inhibitor-rapamycin. Next, macrophages were exposed to S. epidermidis WT and SCV strains. After 4 h incubation, bacterial survival inside macrophages as well as PI3K-mTOR activation was analyzed. SCV strains of S. epidermidis increased the level of Akt phosphorylation, compared to uninfected macrophages and to their parental WT forms. Wild type variants of S. epidermidis phosphorylated Akt at similar or lower levels as control uninfected cells. Next, the induction of mTOR target, phosphorylated ribosomal protein S6, was measured in bacteria-infected macrophages. The level of phosphorylation was significantly reduced when the cells were exposed to WT strains of S. epidermidis. In contrast, the SCV strains activated S6 protein mostly at a level comparable to the control cells. Rapamycin inhibited mTOR activation as the number of p-S6 positive cells decreased in the tested cases. To conclude, the SCV strains activate the PI3K-Akt signaling pathway in opposite to WT strains. This fact however did not influence the increase in the number of live SCV bacteria as compared to the WT strains. Knowing that the PI3K-Akt pathway is involved in proinflammatory cytokines suppression, SCVs seem to use this pathway to reduce the inflammatory response during the infection.
Collapse
Affiliation(s)
- Agnieszka Magryś
- a Chair and Department of Medical Microbiology , Medical University of Lublin , Lublin , Poland
| | - Agnieszka Bogut
- a Chair and Department of Medical Microbiology , Medical University of Lublin , Lublin , Poland
| | - Michał Kiełbus
- b Chair and Department of Biochemistry and Molecular Biology , Medical University of Lublin , Lublin , Poland
| | - Alina Olender
- a Chair and Department of Medical Microbiology , Medical University of Lublin , Lublin , Poland
| |
Collapse
|
42
|
Suwantarat N, Rubin M, Bryan L, Tekle T, Boyle MP, Carroll KC, Jennings MT. Frequency of small-colony variants and antimicrobial susceptibility of methicillin-resistant Staphylococcus aureus in cystic fibrosis patients. Diagn Microbiol Infect Dis 2017; 90:296-299. [PMID: 29343421 DOI: 10.1016/j.diagmicrobio.2017.11.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 11/09/2017] [Accepted: 11/19/2017] [Indexed: 01/15/2023]
Abstract
BACKGROUND Small-colony variants (SCVs) are a distinct phenotype of Staphylococcus aureus, known for their role in chronic, difficult to treat infections, including cystic fibrosis (CF) lung disease. The goal of this study was to characterize SCV MRSA infection in an adult and pediatric CF population and to identify antibiotic susceptibility patterns unique to SCV MRSA. METHODS We recovered methicillin-resistant S. aureus (MRSA) from respiratory culture samples from CF patients at the Johns Hopkins Hospital during a 6month study period. RESULTS Of 1161 samples, 200 isolates (17%) were identified as MRSA, and 37 isolates from 28 patients were identified as SCV MRSA. A higher proportion of MRSA was found among SCV isolates (37/66, 56%) compared to normal colony variant (NCV) isolates (163/417, 39%), p=0.02. All SCV MRSA isolates from individual patients were susceptible to vancomycin and ceftaroline, but they demonstrated higher rates of antibiotic resistance to trimethoprim/sulfamethoxazole, moxifloxacin, and erythromycin, compared to NCV MRSA isolates. Additionally, individuals with SCV MRSA had lower lung function, higher rates of persistent MRSA infection, and higher rates of previous antibiotic use, compared to individuals with NCV MRSA. CONCLUSIONS A significant proportion of MRSA isolates recovered from patients with CF have the SCV morphology. Compared to individuals with NCV MRSA, those with SCV MRSA have higher rates of persistent MRSA infection and lower lung function. SCV MRSA isolates were more resistant than NCV, but they are highly susceptible to vancomycin, linezolid and ceftaroline.
Collapse
Affiliation(s)
- Nuntra Suwantarat
- Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Chulabhorn International College of Medicine, Thammasat University, PathumThani, Thailand
| | - Mayer Rubin
- Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Latetia Bryan
- Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Tsigereda Tekle
- Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Michael P Boyle
- The Cystic Fibrosis Foundation, Bethesda, MD, USA; Division of Pulmonary and Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Karen C Carroll
- Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Mark T Jennings
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| |
Collapse
|
43
|
Sahukhal GS, Pandey S, Elasri MO. msaABCR operon is involved in persister cell formation in Staphylococcus aureus. BMC Microbiol 2017; 17:218. [PMID: 29166860 PMCID: PMC5700755 DOI: 10.1186/s12866-017-1129-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 11/15/2017] [Indexed: 02/02/2023] Open
Abstract
Background Persister cells comprise a phenotypic variant that shows extreme antibiotic tolerance resulting in treatment failures of bacterial infections. While this phenomenon has posed a great threat in public health, mechanisms underlying their formation in Staphylococcus aureus remain largely unknown. Increasing evidences of the presence of persister cells in recalcitrant infections underscores the great urgency to unravel the mechanism by which these cells develop. Previously, we characterized msaABCR operon that plays roles in regulation of virulence, biofilm development and antibiotic resistance. We also characterized the function of MsaB protein and showed that MsaB is a putative transcription factor that binds target DNA in response to nutrients availability. Results In this study, we compared the number of persister cell in wild type, msaABCR deletion mutant and the complemented strain in two backgrounds USA300 LAC and Mu50. Herein, we report that msaABCR deletion mutant forms significantly less number of persister cells relative to wild type after challenge with various antibiotics in planktonic and biofilm growth conditions. Complementation of the msaABCR operon restored wild type phenotype. Combined antibiotic therapy along with msaABCR deletion significantly improves the killing kinetics of stationary phase and biofilm S. aureus cells. Transcriptomics analysis showed that msaABCR regulates several metabolic genes, transcription factors, transporters and enzymes that may play role in persister cells formation, which we seek to define in the future. Conclusions This study presented a new regulator, msaABCR operon, that is involved in the persister cells formation, which is a poorly understood in S. aureus. Indeed, we showed that msaABCR deletion significantly reduces the persister cells formation in all growth phases tested. Although, we have not yet defined the mechanism, we have shown that msaABCR regulates several metabolic, transporters, and extracellular proteases genes that have been previously linked with persister cells formation in other bacterial systems. Taken together, this study showed that inactivation of the msaABCR operon enhances the effectiveness of antibiotics for the treatment of S. aureus infections, especially in context of persister cells. Electronic supplementary material The online version of this article (10.1186/s12866-017-1129-9) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Gyan S Sahukhal
- Department of Biological Sciences, The University of Southern Mississippi, 118 College Drive # 5018, Hattiesburg, MS, 39406-0001, USA
| | - Shanti Pandey
- Department of Biological Sciences, The University of Southern Mississippi, 118 College Drive # 5018, Hattiesburg, MS, 39406-0001, USA
| | - Mohamed O Elasri
- Department of Biological Sciences, The University of Southern Mississippi, 118 College Drive # 5018, Hattiesburg, MS, 39406-0001, USA.
| |
Collapse
|
44
|
The Electron Transport Chain Sensitizes Staphylococcus aureus and Enterococcus faecalis to the Oxidative Burst. Infect Immun 2017; 85:IAI.00659-17. [PMID: 28993457 DOI: 10.1128/iai.00659-17] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 09/28/2017] [Indexed: 12/16/2022] Open
Abstract
Small-colony variants (SCVs) of Staphylococcus aureus typically lack a functional electron transport chain and cannot produce virulence factors such as leukocidins, hemolysins, or the antioxidant staphyloxanthin. Despite this, SCVs are associated with persistent infections of the bloodstream, bones, and prosthetic devices. The survival of SCVs in the host has been ascribed to intracellular residency, biofilm formation, and resistance to antibiotics. However, the ability of SCVs to resist host defenses is largely uncharacterized. To address this, we measured the survival of wild-type and SCV S. aureus in whole human blood, which contains high numbers of neutrophils, the key defense against staphylococcal infection. Despite the loss of leukocidin production and staphyloxanthin biosynthesis, SCVs defective for heme or menaquinone biosynthesis were significantly more resistant to the oxidative burst than wild-type bacteria in human blood or the presence of purified neutrophils. Supplementation of the culture medium of the heme-auxotrophic SCV with heme, but not iron, restored growth, hemolysin and staphyloxanthin production, and sensitivity to the oxidative burst. Since Enterococcus faecalis is a natural heme auxotroph and cause of bloodstream infection, we explored whether restoration of the electron transport chain in this organism also affected survival in blood. Incubation of E. faecalis with heme increased growth and restored catalase activity but resulted in decreased survival in human blood via increased sensitivity to the oxidative burst. Therefore, the lack of functional electron transport chains in SCV S. aureus and wild-type E. faecalis results in reduced growth rate but provides resistance to a key immune defense mechanism.
Collapse
|
45
|
Ochiai Y, Yamada F, Yoshikawa Y, Mochizuki M, Takano T, Hondo R, Ueda F. Sequential transition of the injury phenotype, temperature-dependent survival and transcriptional response in Listeria monocytogenes following lethal H 2 O 2 exposure. Int J Food Microbiol 2017; 259:52-58. [DOI: 10.1016/j.ijfoodmicro.2017.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 07/29/2017] [Accepted: 08/01/2017] [Indexed: 11/29/2022]
|
46
|
Xia H, Tang Q, Song J, Ye J, Wu H, Zhang H. A yigP mutant strain is a small colony variant of E. coli and shows pleiotropic antibiotic resistance. Can J Microbiol 2017; 63:961-969. [PMID: 28915357 DOI: 10.1139/cjm-2017-0347] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Small colony variants (SCVs) are a commonly observed subpopulation of bacteria that have a small colony size and distinctive biochemical characteristics. SCVs are more resistant than the wild type to some antibiotics and usually cause persistent infections in the clinic. SCV studies have been very active during the past 2 decades, especially Staphylococcus aureus SCVs. However, fewer studies on Escherichia coli SCVs exist, so we studied an E. coli SCV during an experiment involving the deletion of the yigP locus. PCR and DNA sequencing revealed that the SCV was attributable to a defect in the yigP function. Furthermore, we investigated the antibiotic resistance profile of the E. coli SCV and it showed increased erythromycin, kanamycin, and d-cycloserine resistance, but collateral sensitivity to ampicillin, polymyxin, chloramphenicol, tetracycline, rifampin, and nalidixic acid. We tried to determine the association between yigP and the pleiotropic antibiotic resistance of the SCV by analyzing biofilm formation, cellular morphology, and coenzyme Q (Q8) production. Our results indicated that impaired Q8 biosynthesis was the primary factor that contributed to the increased resistance and collateral sensitivity of the SCV. This study offers a novel genetic basis for E. coli SCVs and an insight into the development of alternative antimicrobial strategies for clinical therapy.
Collapse
Affiliation(s)
- Hui Xia
- a State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People's Republic of China
| | - Qiongwei Tang
- a State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People's Republic of China
| | - Jie Song
- a State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People's Republic of China
| | - Jiang Ye
- a State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People's Republic of China
| | - Haizhen Wu
- a State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People's Republic of China.,b Department of Applied Biology, East China University of Science and Technology, Shanghai, People's Republic of China
| | - Huizhan Zhang
- a State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People's Republic of China.,b Department of Applied Biology, East China University of Science and Technology, Shanghai, People's Republic of China
| |
Collapse
|
47
|
Prat C, Lacoma A. Bacteria in the respiratory tract-how to treat? Or do not treat? Int J Infect Dis 2017; 51:113-122. [PMID: 27776777 DOI: 10.1016/j.ijid.2016.09.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 08/30/2016] [Accepted: 09/04/2016] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Acute and chronic respiratory tract infections are a common cause of inappropriate antimicrobial prescription. Antimicrobial therapy leads to the development of resistance and the emergence of opportunistic pathogens that substitute the indigenous microbiota. METHODS This review explores the major challenges and lines of research to adequately establish the clinical role of bacteria and the indications for antimicrobial treatment, and reviews novel therapeutic approaches. RESULTS In patients with chronic pulmonary diseases and structural disturbances of the bronchial tree or the lung parenchyma, clinical and radiographic signs and symptoms are almost constantly present, including a basal inflammatory response. Bacterial adaptative changes and differential phenotypes are described, depending on the clinical role and niche occupied. The respiratory tract has areas that are potentially inaccessible to antimicrobials. Novel therapeutic approaches include new ways of administering antimicrobials that may allow intracellular delivery or delivery across biofilms, targeting the functions essential for infection, such as regulatory systems, or the virulence factors required to cause host damage and disease. Alternatives to antibiotics and antimicrobial adjuvants are under development. CONCLUSIONS Prudent treatment, novel targets, and improved drug delivery systems will contribute to reduce the emergence of antimicrobial resistance in lower respiratory tract infections.
Collapse
Affiliation(s)
- Cristina Prat
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Institut d'Investigació Germans Trias i Pujol, Universitat Autònoma de Barcelona, Ctra del Canyet s/n, 08916 Badalona, Barcelona, Spain; CIBER Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain.
| | - Alicia Lacoma
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Institut d'Investigació Germans Trias i Pujol, Universitat Autònoma de Barcelona, Ctra del Canyet s/n, 08916 Badalona, Barcelona, Spain; CIBER Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain
| |
Collapse
|
48
|
Nostro A, Marino A, Ginestra G, Cellini L, Di Giulio M, Bisignano G. Effects of adaptation to carvacrol on Staphylococcus aureus in the planktonic and biofilm phases. BIOFOULING 2017; 33:470-480. [PMID: 28521511 DOI: 10.1080/08927014.2017.1323080] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 04/19/2017] [Indexed: 06/07/2023]
Abstract
The effect of exposure to sub-minimum inhibitory concentrations of carvacrol, for either 3-10 days, on direct (carvacrol) or cross-protection (cinnamaldehyde, eugenol, antibiotics) and the influence on planktonic and biofilm growth of four Staphylococcus aureus strains were reported. The sequential exposure to carvacrol resulted in a direct protection that was more evident in two of the four strains after 10 days. No significant cross-protection against cinnamaldehyde, eugenol and antibiotics was detected. An adaptive response was associated with a prolonged lag phase, a lower yield of bacteria, a colony phenotype likely to be associated to small colony variants and an increase in biofilm production. Generally, the biofilm of the adapted strains was less susceptible to subMICs of carvacrol compared to the biofilms of non-adapted strains. In contrast, it was demonstrated that in the case of mature biofilms the susceptibility was similar. The exposure of S. aureus to carvacrol at concentrations above the MIC resulted in a very low mutation frequency.
Collapse
Affiliation(s)
- Antonia Nostro
- a Department of Chemical, Biological, Pharmaceutical and Environmental Sciences , University of Messina , Messina , Italy
| | - Andreana Marino
- a Department of Chemical, Biological, Pharmaceutical and Environmental Sciences , University of Messina , Messina , Italy
| | - Giovanna Ginestra
- a Department of Chemical, Biological, Pharmaceutical and Environmental Sciences , University of Messina , Messina , Italy
| | - Luigina Cellini
- b Department of Pharmacy , University "G. d'Annunzio" Chieti-Pescara , Chieti , Italy
| | - Mara Di Giulio
- b Department of Pharmacy , University "G. d'Annunzio" Chieti-Pescara , Chieti , Italy
| | - Giuseppe Bisignano
- a Department of Chemical, Biological, Pharmaceutical and Environmental Sciences , University of Messina , Messina , Italy
| |
Collapse
|
49
|
Rodríguez-Arce I, Martí S, Euba B, Fernández-Calvet A, Moleres J, López-López N, Barberán M, Ramos-Vivas J, Tubau F, Losa C, Ardanuy C, Leiva J, Yuste JE, Garmendia J. Inactivation of the Thymidylate Synthase thyA in Non-typeable Haemophilus influenzae Modulates Antibiotic Resistance and Has a Strong Impact on Its Interplay with the Host Airways. Front Cell Infect Microbiol 2017; 7:266. [PMID: 28676846 PMCID: PMC5476696 DOI: 10.3389/fcimb.2017.00266] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 06/02/2017] [Indexed: 12/29/2022] Open
Abstract
Antibacterial treatment with cotrimoxazol (TxS), a combination of trimethoprim and sulfamethoxazole, generates resistance by, among others, acquisition of thymidine auxotrophy associated with mutations in the thymidylate synthase gene thyA, which can modify the biology of infection. The opportunistic pathogen non-typeable Haemophilus influenzae (NTHi) is frequently encountered in the lower airways of chronic obstructive pulmonary disease (COPD) patients, and associated with acute exacerbation of COPD symptoms. Increasing resistance of NTHi to TxS limits its suitability as initial antibacterial against COPD exacerbation, although its relationship with thymidine auxotrophy is unknown. In this study, the analysis of 2,542 NTHi isolates recovered at Bellvitge University Hospital (Spain) in the period 2010–2014 revealed 119 strains forming slow-growing colonies on the thymidine low concentration medium Mueller Hinton Fastidious, including one strain isolated from a COPD patient undergoing TxS therapy that was a reversible thymidine auxotroph. To assess the impact of thymidine auxotrophy in the NTHi-host interplay during respiratory infection, thyA mutants were generated in both the clinical isolate NTHi375 and the reference strain RdKW20. Inactivation of the thyA gene increased TxS resistance, but also promoted morphological changes consistent with elongation and impaired bacterial division, which altered H. influenzae self-aggregation, phosphorylcholine level, C3b deposition, and airway epithelial infection patterns. Availability of external thymidine contributed to overcome such auxotrophy and TxS effect, potentially facilitated by the nucleoside transporter nupC. Although, thyA inactivation resulted in bacterial attenuation in a lung infection mouse model, it also rendered a lower clearance upon a TxS challenge in vivo. Thus, our results show that thymidine auxotrophy modulates both the NTHi host airway interplay and antibiotic resistance, which should be considered at the clinical setting for the consequences of TxS administration.
Collapse
Affiliation(s)
- Irene Rodríguez-Arce
- Instituto de Agrobiotecnología, Consejo Superior de Investigaciones Científicas-Universidad Pública Navarra-GobiernoNavarra, Spain
| | - Sara Martí
- Centro de Investigación Biomédica en Red de Enfermedades RespiratoriasMadrid, Spain.,Departamento Microbiología, Hospital Universitari Bellvitge, University of Barcelona, Institut d'Investigació Biomédica de BellvitgeBarcelona, Spain
| | - Begoña Euba
- Instituto de Agrobiotecnología, Consejo Superior de Investigaciones Científicas-Universidad Pública Navarra-GobiernoNavarra, Spain.,Centro de Investigación Biomédica en Red de Enfermedades RespiratoriasMadrid, Spain
| | - Ariadna Fernández-Calvet
- Instituto de Agrobiotecnología, Consejo Superior de Investigaciones Científicas-Universidad Pública Navarra-GobiernoNavarra, Spain
| | - Javier Moleres
- Instituto de Agrobiotecnología, Consejo Superior de Investigaciones Científicas-Universidad Pública Navarra-GobiernoNavarra, Spain
| | - Nahikari López-López
- Instituto de Agrobiotecnología, Consejo Superior de Investigaciones Científicas-Universidad Pública Navarra-GobiernoNavarra, Spain
| | | | - José Ramos-Vivas
- Servicio Microbiología, Hospital Universitario Marqués de Valdecilla and Instituto de Investigación Marqués de ValdecillaSantander, Spain.,Red Española de Investigación en Patología Infecciosa, Instituto de Salud Carlos IIIMadrid, Spain
| | - Fe Tubau
- Centro de Investigación Biomédica en Red de Enfermedades RespiratoriasMadrid, Spain.,Departamento Microbiología, Hospital Universitari Bellvitge, University of Barcelona, Institut d'Investigació Biomédica de BellvitgeBarcelona, Spain
| | - Carmen Losa
- Servicio de Microbiología, Clínica Universidad de NavarraNavarra, Spain
| | - Carmen Ardanuy
- Centro de Investigación Biomédica en Red de Enfermedades RespiratoriasMadrid, Spain.,Departamento Microbiología, Hospital Universitari Bellvitge, University of Barcelona, Institut d'Investigació Biomédica de BellvitgeBarcelona, Spain
| | - José Leiva
- Servicio de Microbiología, Clínica Universidad de NavarraNavarra, Spain
| | - José E Yuste
- Centro de Investigación Biomédica en Red de Enfermedades RespiratoriasMadrid, Spain.,Centro Nacional de Microbiología, Instituto de Salud Carlos IIIMadrid, Spain
| | - Junkal Garmendia
- Instituto de Agrobiotecnología, Consejo Superior de Investigaciones Científicas-Universidad Pública Navarra-GobiernoNavarra, Spain.,Centro de Investigación Biomédica en Red de Enfermedades RespiratoriasMadrid, Spain
| |
Collapse
|
50
|
Zhang P, Wright JA, Osman AA, Nair SP. An aroD Ochre Mutation Results in a Staphylococcus aureus Small Colony Variant That Can Undergo Phenotypic Switching via Two Alternative Mechanisms. Front Microbiol 2017; 8:1001. [PMID: 28620368 PMCID: PMC5449664 DOI: 10.3389/fmicb.2017.01001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 05/18/2017] [Indexed: 12/11/2022] Open
Abstract
Staphylococcus aureus can undergo phenotypic switching between a normal colony phenotype (NCP) and a small colony variant (SCV). The SCV phenotype confers increased antibiotic resistance and the capacity to persist within human tissues and cells, and because these cells can revert back to the NCP they cause chronic and/or recurrent infections that are very difficult to treat. A complete picture of the genetic events that can lead to phenotypic switching in S. aureus is currently lacking. We describe the selection of an SCV with a previously unreported genetic alteration leading to an ochre mutation of aroD. In addition to the known mechanisms of phenotypic switching between the SCV and the NCP we describe a previously unreported mechanism involving tRNA ochre suppressors arising. The ochre suppressor strains had wild-type growth rates and restored antibiotic sensitivity, similar to the wild-type strain. However, whilst they had increased virulence compared to the SCV parent strain, their virulence was not restored to that of the NCP parental strain. These findings establish that phenotypic switching between the NCP and SCV states can give rise to strains with different pathogenic potential.
Collapse
Affiliation(s)
- Ping Zhang
- Department of Microbial Diseases, UCL Eastman Dental Institute, University College LondonLondon, United Kingdom
| | - John A Wright
- Immunology Catalyst, GlaxoSmithKline plcStevenage, United Kingdom
| | - Ahmed A Osman
- Department of Microbial Diseases, UCL Eastman Dental Institute, University College LondonLondon, United Kingdom
| | - Sean P Nair
- Department of Microbial Diseases, UCL Eastman Dental Institute, University College LondonLondon, United Kingdom
| |
Collapse
|