1
|
Yamazaki Y, Ito T, Tamai M, Nakagawa S, Nakamura Y. The role of Staphylococcus aureus quorum sensing in cutaneous and systemic infections. Inflamm Regen 2024; 44:9. [PMID: 38429810 PMCID: PMC10905890 DOI: 10.1186/s41232-024-00323-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 02/15/2024] [Indexed: 03/03/2024] Open
Abstract
BACKGROUND Staphylococcus aureus is a leading cause of human bacterial infections worldwide. It is the most common causative agent of skin and soft tissue infections, and can also cause various other infections, including pneumonia, osteomyelitis, as well as life-threatening infections, such as sepsis and infective endocarditis. The pathogen can also asymptomatically colonize human skin, nasal cavity, and the intestine. S. aureus colonizes approximately 20-30% of human nostrils, being an opportunistic pathogen for subsequent infection. Its strong ability to silently spread via human contact makes it difficult to eradicate S. aureus. A major concern with S. aureus is its capacity to develop antibiotic resistance and adapt to diverse environmental conditions. The variability in the accessory gene regulator (Agr) region of the genome contributes to a spectrum of phenotypes within the bacterial population, enhancing the likelihood of survival in different environments. Agr functions as a central quorum sensing (QS) system in S. aureus, allowing bacteria to adjust gene expression in response to population density. Depending on Agr expression, S. aureus secretes various toxins, contributing to virulence in infectious diseases. Paradoxically, expressing Agr may be disadvantageous in certain situations, such as in hospitals, causing S. aureus to generate Agr mutants responsible for infections in healthcare settings. MAIN BODY This review aims to demonstrate the molecular mechanisms governing the diverse phenotypes of S. aureus, ranging from a harmless colonizer to an organism capable of infecting various human organs. Emphasis will be placed on QS and its role in orchestrating S. aureus behavior across different contexts. SHORT CONCLUSION The pathophysiology of S. aureus infection is substantially influenced by phenotypic changes resulting from factors beyond Agr. Future studies are expected to give the comprehensive understanding of S. aureus overall profile in various settings.
Collapse
Affiliation(s)
- Yuriko Yamazaki
- Cutaneous Allergy and Host Defense, Immunology Frontier Research Center, Osaka, University, Osaka, 565-0871, Japan
- Department of Dermatology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan
| | - Tomoka Ito
- Department of Dermatology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan
| | - Masakazu Tamai
- Department of Dermatology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan
| | - Seitaro Nakagawa
- Department of Dermatology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan
| | - Yuumi Nakamura
- Cutaneous Allergy and Host Defense, Immunology Frontier Research Center, Osaka, University, Osaka, 565-0871, Japan.
- Department of Dermatology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan.
| |
Collapse
|
2
|
Jiang JH, Cameron DR, Nethercott C, Aires-de-Sousa M, Peleg AY. Virulence attributes of successful methicillin-resistant Staphylococcus aureus lineages. Clin Microbiol Rev 2023; 36:e0014822. [PMID: 37982596 PMCID: PMC10732075 DOI: 10.1128/cmr.00148-22] [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] [Indexed: 11/21/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of severe and often fatal infections. MRSA epidemics have occurred in waves, whereby a previously successful lineage has been replaced by a more fit and better adapted lineage. Selection pressures in both hospital and community settings are not uniform across the globe, which has resulted in geographically distinct epidemiology. This review focuses on the mechanisms that trigger the establishment and maintenance of current, dominant MRSA lineages across the globe. While the important role of antibiotic resistance will be mentioned throughout, factors which influence the capacity of S. aureus to colonize and cause disease within a host will be the primary focus of this review. We show that while MRSA possesses a diverse arsenal of toxins including alpha-toxin, the success of a lineage involves more than just producing toxins that damage the host. Success is often attributed to the acquisition or loss of genetic elements involved in colonization and niche adaptation such as the arginine catabolic mobile element, as well as the activity of regulatory systems, and shift metabolism accordingly (e.g., the accessory genome regulator, agr). Understanding exactly how specific MRSA clones cause prolonged epidemics may reveal targets for therapies, whereby both core (e.g., the alpha toxin) and acquired virulence factors (e.g., the Panton-Valentine leukocidin) may be nullified using anti-virulence strategies.
Collapse
Affiliation(s)
- Jhih-Hang Jiang
- Department of Microbiology, Infection Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - David R. Cameron
- Department of Biomedical Research, University of Bern, Bern, Switzerland
| | - Cara Nethercott
- Department of Microbiology, Infection Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Marta Aires-de-Sousa
- Laboratory of Molecular Genetics, Institutode Tecnologia Químicae Biológica António Xavier (ITQB-NOVA), Universidade Nova de Lisboa, Oeiras, Portugal
- Escola Superior de Saúde da Cruz Vermelha Portuguesa-Lisboa (ESSCVP-Lisboa), Lisbon, Portugal
| | - Anton Y. Peleg
- Department of Microbiology, Infection Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne, Victoria, Australia
- Centre to Impact Antimicrobial Resistance, Monash University, Clayton, Melbourne, Victoria, Australia
| |
Collapse
|
3
|
Jiang S, Chen M, Zhang J, Ba X, Zhang H, Hong Y, Sun L, Wang Z, Zhuang H, Zhu F, Chen Y, Wang H, Zhao F, Chen Y, Yu Y, Ji S. Profiling daptomycin resistance among diverse methicillin-resistant Staphylococcus aureus lineages in China. Antimicrob Agents Chemother 2023; 67:e0056323. [PMID: 37902403 PMCID: PMC10649010 DOI: 10.1128/aac.00563-23] [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: 05/01/2023] [Accepted: 09/15/2023] [Indexed: 10/31/2023] Open
Abstract
Daptomycin (DAP) is effective against methicillin-resistant Staphylococcus aureus (MRSA). However, reduced susceptibility to DAP in MRSA may lead to treatment failures. We aim to determine the distribution of DAP minimum inhibitory concentrations (MICs) and DAP heteroresistance (hDAP) among MRSA lineages in China. A total of 472 clinical MRSA isolates collected from 2015 to 2017 in China were examined for DAP susceptibility. All isolates (n = 472) were found to be DAP susceptible, but 35.17% (166/472) of them exhibited a high DAP MIC (MIC >0.5 µg/mL). The high DAP MIC group contained a larger proportion of isolates with a higher vancomycin or teicoplanin MIC (>1.5 µg/mL) than the low DAP MIC group (19.3% vs 7.8%, P < 0.001; 22.3% vs 8.2%, P < 0.001). We compared the clonal complex (CC) distributions and clinical characteristics in MRSA isolates stratified by DAP MIC. CC5 isolates were less susceptible to DAP (MIC50 = 1 µg/mL) than CC59 isolates (MIC50 = 0.5 µg/mL, P < 0.001). Population analysis profiling revealed that 5 of 10 ST5 and ST59 DAP-susceptible MRSA isolates investigated exhibited hDAP. The results also showed that CC5 MRSA with an agrA mutation (I238K) had a higher DAP MIC than those with a wild-type agrA (P < 0.001). The agrA-I238K mutation was found to be associated with agr dysfunction as indicated by the loss of δ-hemolysin production. In addition, agr/psmα defectiveness was associated with hDAP in MRSA. Whole-genome sequencing analysis revealed mutations in mprF and walR/walK in DAP-resistant subpopulations, and most DAP-resistant subpopulations (6/8, 75%) were stable. Our study suggests that the increased DAP resistance and hDAP in MRSA may threaten the effectiveness against MRSA infections.
Collapse
Affiliation(s)
- Shengnan Jiang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Mengzhen Chen
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Junxiong Zhang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Xihu District Center for Disease Control and Prevention of Hangzhou, Hangzhou, China
| | - Xiaoliang Ba
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Hao Zhang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yueqin Hong
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Lu Sun
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhengan Wang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Hemu Zhuang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Feiteng Zhu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yiyi Chen
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Haiping Wang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Feng Zhao
- Department of Clinical laboratory, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yan Chen
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yunsong Yu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Shujuan Ji
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| |
Collapse
|
4
|
Parsons JB, Westgeest AC, Conlon BP, Fowler VG. Persistent Methicillin-Resistant Staphylococcus aureus Bacteremia: Host, Pathogen, and Treatment. Antibiotics (Basel) 2023; 12:455. [PMID: 36978320 PMCID: PMC10044482 DOI: 10.3390/antibiotics12030455] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/18/2023] [Accepted: 02/20/2023] [Indexed: 03/02/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a devastating pathogen responsible for a variety of life-threatening infections. A distinctive characteristic of this pathogen is its ability to persist in the bloodstream for several days despite seemingly appropriate antibiotics. Persistent MRSA bacteremia is common and is associated with poor clinical outcomes. The etiology of persistent MRSA bacteremia is a result of the complex interplay between the host, the pathogen, and the antibiotic used to treat the infection. In this review, we explore the factors related to each component of the host-pathogen interaction and discuss the clinical relevance of each element. Next, we discuss the treatment options and diagnostic approaches for the management of persistent MRSA bacteremia.
Collapse
Affiliation(s)
- Joshua B. Parsons
- Department of Medicine, Division of Infectious Disease, Duke University Medical Center, Durham, NC 27710, USA
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Annette C. Westgeest
- Department of Medicine, Division of Infectious Disease, Duke University Medical Center, Durham, NC 27710, USA
- Department of Infectious Diseases, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Brian P. Conlon
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Vance G. Fowler
- Department of Medicine, Division of Infectious Disease, Duke University Medical Center, Durham, NC 27710, USA
- Duke Clinical Research Institute, Durham, NC 27710, USA
| |
Collapse
|
5
|
Bae S, Kim ES, Lee YW, Jung J, Kim MJ, Chong YP, Kim SH, Choi SH, Lee SO, Kim YS. Clinical and microbiological characteristics of rifampicin-resistant MRSA bacteraemia. J Antimicrob Chemother 2023; 78:531-539. [PMID: 36537200 DOI: 10.1093/jac/dkac428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 11/15/2022] [Indexed: 12/24/2022] Open
Abstract
OBJECTIVES The clinical significance of rifampicin resistance in Staphylococcus aureus infections has not been demonstrated. Here, we evaluated the clinical characteristics of rifampicin-resistant S. aureus infection. METHODS Data were collected from adult patients who were hospitalized with MRSA bacteraemia between March 2007 and May 2020 at a tertiary hospital in South Korea. The clinical characteristics and treatment outcomes of patients infected with rifampicin-resistant MRSA were compared with those of rifampicin-susceptible isolates. All-cause death and recurrence of MRSA infection were assessed for 90 days. RESULTS Of the 961 patients with MRSA bacteraemia, 61 (6.3%) were infected by rifampicin-resistant isolates. The type of infection focus and duration of bacteraemia did not significantly differ between the two groups. Rifampicin-resistant MRSA isolates were more likely to have multidrug resistance and a higher vancomycin MIC relative to the rifampicin-susceptible isolates. The 90-day recurrence rate was higher in the patients infected with rifampicin-resistant MRSA compared with those with rifampicin-susceptible MRSA (18.0% versus 6.2%, P < 0.001), whereas the 90-day mortality was comparable between the two groups (27.9% versus 29.2%, P = 0.94). After adjusting for potential confounding factors, rifampicin resistance was significantly associated with 90-day recurrence (subdistributional HR: 2.31; 95% CI: 1.05-5.10; P = 0.04). CONCLUSIONS Rifampicin-resistant MRSA isolates showed distinct microbiological features in terms of multidrug resistance and a high vancomycin MIC. Although the management of MRSA bacteraemia was not significantly different between the two groups, recurrence was significantly more common in the rifampicin-resistant group. Rifampicin resistance may play a significant role in infection recurrence.
Collapse
Affiliation(s)
- Seongman Bae
- Division of Infectious Diseases, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.,Center for Antimicrobial Resistance and Microbial Genetics, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Eun Sil Kim
- Division of Infectious Diseases, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.,Center for Antimicrobial Resistance and Microbial Genetics, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Yun Woo Lee
- Division of Infectious Diseases, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.,Center for Antimicrobial Resistance and Microbial Genetics, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Jiwon Jung
- Division of Infectious Diseases, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Min Jae Kim
- Division of Infectious Diseases, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Yong Pil Chong
- Division of Infectious Diseases, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Sung-Han Kim
- Division of Infectious Diseases, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Sang-Ho Choi
- Division of Infectious Diseases, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Sang-Oh Lee
- Division of Infectious Diseases, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Yang Soo Kim
- Division of Infectious Diseases, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.,Center for Antimicrobial Resistance and Microbial Genetics, University of Ulsan College of Medicine, Seoul, Republic of Korea
| |
Collapse
|
6
|
Patil S, Dong S, Sharma D, Lopes BS, Hanafiah A, Chen X, Wen F. Molecular Epidemiology and Characterization of Multidrug-Resistant MRSA ST398 and ST239 in Himachal Pradesh, India. Infect Drug Resist 2023; 16:2339-2348. [PMID: 37125211 PMCID: PMC10134341 DOI: 10.2147/idr.s409037] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 04/15/2023] [Indexed: 05/02/2023] Open
Abstract
Aim Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of severe and difficult-to-treat infections in humans and animals. We aimed to identify the predominant lineages of methicillin-resistant S. aureus in Himachal Pradesh, India, to understand the genomic epidemiology along with the genotypic and phenotypic characteristics. Methods We isolated 250 S. aureus from two district hospitals in Himachal Pradesh, India. Methicillin-Resistant S. aureus (MRSA) isolates were subjected to MLST, SCCmec typing, and resistance as well as virulence determinants were determined by PCR and sequencing. Bio-typing was also performed for source tracking. Results A 17.6% (44/250) of isolates were classified as MRSA by both the MRSA detection kit and disc diffusion methods. Antimicrobial Susceptibility Testing of MRSA isolates (n = 44) showed high resistance to oxacillin (77.27%), erythromycin (77.27%), tetracycline (75%), cefoxitin (65.9%), and gentamicin (61.36%), while low resistance was observed for teicoplanin (36.36%), vancomycin and levofloxacin (31.81%) and fusidic acid (18.18%). All isolates were sensitive to linezolid, quinupristin-dulfopristin, dalbavancin, and cefazoline. The SCCmec-II was observed in 20.45% of isolates, SCCmec-I in 11.36%, SCCmec-III in 9%, SCCmec-IV in 40.9% and SCCmec-V in 18.18%. The mecA gene was present in all isolates (n = 44) and 50% also had the vanA gene. 35% of isolates had the lukS-PV/lukf-PV toxin gene and 11.36% had the co-existence of mecA, vanA, and lukS-PV/lukf-PV. The major strain was ST398 (39%) followed by ST239 (27%), ST217 (16%), ST121 (11%), and ST338 (7%). The MRSA isolates produced staphylokinase and β-hemolysis but were negative for bovine plasma coagulation tests. In Conclusion The predominant MRSA clones in Himachal Pradesh, India, were hospital-associated multi-drug resistant-MRSA ST239 with PVL and community-associated MRSA ST398.
Collapse
Affiliation(s)
- Sandip Patil
- Department of Haematology and Oncology, Shenzhen Children’s Hospital, Shenzhen, People’s Republic of China
- Paediatric Research Institute, Shenzhen Children’s Hospital, Shenzhen, People’s Republic of China
| | - Shaowei Dong
- Paediatric Research Institute, Shenzhen Children’s Hospital, Shenzhen, People’s Republic of China
| | - Devender Sharma
- Department of Microbiology, Himachal Dental College, Sundar Nagar, Himachal Pradesh, India
- School of Biotechnology, Shoolini University, Solan, Himachal Pradesh, India
| | - Bruno Silvester Lopes
- School of Health and Life Sciences, Teesside University, Middlesbrough, TS1 3BA, UK
- National Horizons Centre, Teesside University, Darlington, DL1 1HG, UK
| | - Alfizah Hanafiah
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Xiaowen Chen
- Paediatric Research Institute, Shenzhen Children’s Hospital, Shenzhen, People’s Republic of China
| | - Feiqiu Wen
- Department of Haematology and Oncology, Shenzhen Children’s Hospital, Shenzhen, People’s Republic of China
- Paediatric Research Institute, Shenzhen Children’s Hospital, Shenzhen, People’s Republic of China
- Correspondence: Feiqiu Wen, Department of Haematology and Oncology, Shenzhen Children’s Hospital, Shenzhen, Guangdong, People’s Republic of China, Tel +86-755-83009888, Email
| |
Collapse
|
7
|
Genotypes of Staphylococcus aureus Clinical Isolates Are Associated with Phenol-Soluble Modulin (PSM) Production. Toxins (Basel) 2022; 14:toxins14080556. [PMID: 36006218 PMCID: PMC9412541 DOI: 10.3390/toxins14080556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/06/2022] [Accepted: 08/12/2022] [Indexed: 12/01/2022] Open
Abstract
Phenol-soluble modulins (PSMs) are important S. aureus virulence factors that cause cytolysis, mast cell degranulation, and stimulate inflammatory responses. In this study, PSM production by S. aureus clinical isolates was measured by liquid chromatography/mass spectrometry (LC-MS) and correlated with staphylococcal protein A (spa) type and staphylococcal cassette chromosome mec (SCCmec) type. Of 106 S. aureus clinical isolates, 50 (47.2%) corresponded to methicillin-susceptible S. aureus (MSSA) and 56 (52.8%) to methicillin-resistant S. aureus (MRSA). LC-MS analysis revealed no significant difference in average PSMα3, PSMα4, PSMβ2, and δ-toxin production between MSSA and MRSA isolates, but PSMα1, PSMα2, and PSMβ1 production were higher in MSSA than MRSA. This study demonstrated that average PSMα1–α4, PSMβ1–β2, and δ-toxin production by SCCmec type II strains was significantly lower than the IV, IVA, and V strains. Most of the SCCmec type II strains (n = 17/25; 68.0%) did not produce δ-toxin, suggesting a dysfunctional Agr system. The spa type t111 (except one strain) and t2460 (except one strain producing PSM α1–α4) did not produce PSMα1–α4 and δ-toxin, while average PSM production was higher among the t126 and t1784 strains. This study showed that the genotype of S. aureus, specifically the spa and SCCmec types, is important in characterizing the production of PSMs.
Collapse
|
8
|
Risk Factors of Recurrent Infection in Patients with Staphylococcus aureus Bacteremia: a Competing Risk Analysis. Antimicrob Agents Chemother 2022; 66:e0012622. [PMID: 35762799 PMCID: PMC9295554 DOI: 10.1128/aac.00126-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Although several clinical variables have been reported as risk factors for recurrence of Staphylococcus aureus infection, most studies have not considered competing risk events that may overestimate the risk. In this study, we performed competing risk analysis to identify risk factors related to 90-day recurrence in patients with S. aureus bacteremia (SAB) using a large cohort data from a single tertiary hospital in South Korea. All adults who experienced SAB during admission were prospectively enrolled from August 2008 to December 2019. After the day of the first positive blood culture, recurrence and all-cause mortality were assessed for 90 days. Recurrence was defined as a development of symptoms or signs of infection with or without repeated bacteremia after >7 days of negative blood culture and clinically apparent improvement. Subdistribution hazard ratios (sHR) for recurrence and all-cause mortality were estimated using Fine and Gray models. Of 1,725 SAB patients, including 885 cases (51.3%) of methicillin-resistant S. aureus (MRSA) bacteremia, 85 (5.0%) experienced recurrence during the study period. In a multivariate Fine and Gray regression model, the presence of a vascular graft (subdistribution HR [sHR], 3.48; 95% confidence interval [CI], 1.90-6.40), nasal MRSA carriage (sHR, 2.10; 95% CI, 1.28-3.44), methicillin resistance (sHR, 1.69; 95% CI, 1.00-2.84), and rifampicin resistance (sHR, 2.20; 95% CI, 1.12-4.33) were significantly associated with 90-day recurrence. In a large cohort of SAB patients with a high prevalence of MRSA, indwelling vascular graft, nasal MRSA carriage, methicillin resistance, and rifampicin resistance were potential risk factors for recurrence of S. aureus infection.
Collapse
|
9
|
Kim H, Park S, Seo H, Chung H, Kim ES, Sung H, Kim MN, Bae S, Jung J, Kim MJ, Kim SH, Lee SO, Choi SH, Kim YS, Chong YP. Clinical impact of and microbiological risk factors for qacA/B positivity in ICU-acquired ST5-methicillin-resistant SCCmec type II Staphylococcus aureus bacteremia. Sci Rep 2022; 12:11413. [PMID: 35794229 PMCID: PMC9259651 DOI: 10.1038/s41598-022-15546-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 06/24/2022] [Indexed: 12/14/2022] Open
Abstract
Concern about resistance to chlorhexidine has increased due to the wide use of the latter. The impact of the qacA/B and smr chlorhexidine tolerance genes on the outcome of methicillin-resistant Staphylococcus aureus (MRSA) infections is unclear. We evaluated the prevalence and clinical impact of, and microbiological risk factors for, qacA/B tolerance in MRSA bacteremia. MRSA bacteremia that occurred more than two days after intensive care unit admission between January 2009 and December 2018 was identified from a prospective cohort of S. aureus bacteremia in a tertiary-care hospital from South Korea. A total of 183 MRSA blood isolates was identified, and the major genotype found was ST5-MRSA-II (87.4%). The prevalences of qacA/B and smr were 67.2% and 3.8%, respectively. qacA/B-positive isolates were predominantly ST5-MRSA-II (96.7% [119/123]), the dominant hospital clone. In a homogenous ST5-MRSA-II background, qacA/B positivity was independently associated with septic shock (aOR, 4.85), gentamicin resistance (aOR, 74.43), and non-t002 spa type (aOR, 74.12). qacA/B positivity was found to have decreased significantly in ST5-MRSA-II in association with a decline in qacA/B-positive t2460, despite the increasing use of chlorhexidine since 2010 (P < 0.001 for trend). Continuous surveillance of the qac genes, and molecular characterization of their plasmids, are needed to understand their role in MRSA epidemiology.
Collapse
Affiliation(s)
- Haein Kim
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro-43-gil, Songpa-gu, Seoul, 05505, South Korea
| | - Sunghee Park
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro-43-gil, Songpa-gu, Seoul, 05505, South Korea
| | - Hyeonji Seo
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro-43-gil, Songpa-gu, Seoul, 05505, South Korea
| | - Hyemin Chung
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro-43-gil, Songpa-gu, Seoul, 05505, South Korea
| | - Eun Sil Kim
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro-43-gil, Songpa-gu, Seoul, 05505, South Korea
- Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Heungsup Sung
- Department of Laboratory Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Mi-Na Kim
- Department of Laboratory Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Seongman Bae
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro-43-gil, Songpa-gu, Seoul, 05505, South Korea
| | - Jiwon Jung
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro-43-gil, Songpa-gu, Seoul, 05505, South Korea
| | - Min Jae Kim
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro-43-gil, Songpa-gu, Seoul, 05505, South Korea
| | - Sung-Han Kim
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro-43-gil, Songpa-gu, Seoul, 05505, South Korea
| | - Sang-Oh Lee
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro-43-gil, Songpa-gu, Seoul, 05505, South Korea
| | - Sang-Ho Choi
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro-43-gil, Songpa-gu, Seoul, 05505, South Korea
| | - Yang Soo Kim
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro-43-gil, Songpa-gu, Seoul, 05505, South Korea
| | - Yong Pil Chong
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro-43-gil, Songpa-gu, Seoul, 05505, South Korea.
| |
Collapse
|
10
|
Abd El-Hamid MI, Sewid AH, Samir M, Hegazy WAH, Bahnass MM, Mosbah RA, Ghaith DM, Khalifa E, Ramadan H, Alshareef WA, Alshareef HM, Ghoneim MM, Al-Sanea MM, Bendary MM. Clonal Diversity and Epidemiological Characteristics of ST239-MRSA Strains. Front Cell Infect Microbiol 2022; 12:782045. [PMID: 35402300 PMCID: PMC8990901 DOI: 10.3389/fcimb.2022.782045] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 02/16/2022] [Indexed: 12/14/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen associated with severe morbidity and mortality and poses a significant threat to public health worldwide. The genetic diversity based on sequence types of MRSA strains was illustrated in previous studies; meanwhile, the diversity along with the predominant sequence type, especially in Egypt, remains unknown. The purpose of the current study was to determine the diversity of the predominant MRSA clone ST239-MRSA (n = 50) isolated from different hosts and clinical samples and to illustrate the correlation between the resistance patterns, toxin genes, and the genetic background in Port-said and El-Sharkia Governorates, Egypt. The ST239-MRSA clone was analyzed by phenotypic antibiotyping and various genotypic assays comprising SCCmec, agr, spa, coa, and coa-RFLP in addition to toxin gene profiles. Most of the analyzed strains (40/50, 80%) were multidrug resistant (MDR), belonged to SCCmec-III, agr-I, and coa genotype I, and harbored sea and pvl genes. A negative correlation between the toxin gene profiles and antimicrobial resistance was recorded. Meanwhile, the correlation between the toxin gene profiles and the genetic background was not observed in this study. Although ST239-MRSA strains belonged to a single sequence type, they exhibited a high degree of phenotypic and genotypic diversity, indicating weak clonality and adaptability. With such diversity, it is assumed that these strains may have undergone different evolutionary processes during transmission events among and/or within a single host or tissue niche.
Collapse
Affiliation(s)
- Marwa I Abd El-Hamid
- Department of Microbiology, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt
| | - Alaa H Sewid
- Department of Microbiology, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt
| | - Mohamed Samir
- Department of Zoonoses, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt
| | - Wael A H Hegazy
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
| | - Mosa M Bahnass
- Department of Animal Medicine (Infectious Disease), Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt
| | - Rasha A Mosbah
- Fellow Pharmacist, Zagazig University Hospital, Zagazig, Egypt
| | - Doaa M Ghaith
- Department of Clinical and Chemical Pathology, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Eman Khalifa
- Department of Microbiology, Faculty of Veterinary Medicine, Matrouh University, Matrouh, Egypt
| | - Hazem Ramadan
- Hygiene and Zoonoses Department, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt
| | - Walaa A Alshareef
- Department of Microbiology, Faculty of Pharmacy, October 6 University, 6th of October, Egypt
| | - Hanan M Alshareef
- Department of Pharmacy Practice, Faculty of Pharmacy, University of Tabuk, Tabuk, Saudi Arabia
| | - Mohammed M Ghoneim
- Department of Pharmacy Practice, College of Pharmacy, Al Maarefa University, Ad Diriyah, Saudi Arabia
| | - Mohammad M Al-Sanea
- Pharmaceutical Chemistry Department, College of Pharmacy, Jouf University, Sakaka, Saudi Arabia
| | - Mahmoud M Bendary
- Department of Microbiology and Immunology, Faculty of Pharmacy, Port Said University, Port Said, Egypt
| |
Collapse
|
11
|
Kwiatkowski P, Masiuk H, Pruss A, Łopusiewicz Ł, Sienkiewicz M, Wojciechowska-Koszko I, Roszkowska P, Bania J, Guenther S, Dołęgowska B. Clonal Diversity, Antimicrobial Susceptibility and Presence of Genes Encoding Virulence Factors in Staphylococcus aureus Strains Isolated from Cut Wound Infections. Curr Microbiol 2022; 79:144. [PMID: 35325311 DOI: 10.1007/s00284-022-02835-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 03/10/2022] [Indexed: 11/03/2022]
Abstract
The aim of the study was to evaluate the clonal relatedness and antimicrobial susceptibility in 52 Staphylococcus aureus strains isolated from cut wound infections in non-related community patients and to determine the presence of selected virulence genes. To analyse the clonal relatedness of investigated strains, pulsed-field gel electrophoresis (PFGE) of macrorestricted DNA fragments was conducted. Antimicrobial susceptibility testing was performed using the AST-P644 card in the VITEK 2 Compact system. All strains were tested for the presence of selected virulence genes using Single and Multiplex PCR. All isolates were classified into 15 PFGE genotypes and seven unique patterns. The vast majority of investigated S. aureus strains were susceptible to all tested antimicrobial agents. Among examined S. aureus strains, 24 combinations of virulence factors were identified. 62.5% of S. aureus strains contained various egc types, alone or together with other staphylococcal enterotoxin genes. A high percentage (86.5%) of isolates harboured superantigen genes. The most frequent enterotoxin gene identified was encoding for sep. All S. aureus strains were classified as agr-positive, and the most frequent agr gene was agr-1. Our results indicate that all examined strains isolated from cut wound infections demonstrated high clonal diversity, diversified gene distribution and good susceptibility to antimicrobial agents.
Collapse
Affiliation(s)
- Paweł Kwiatkowski
- Department of Diagnostic Immunology, Chair of Microbiology, Immunology and Laboratory Medicine, Pomeranian Medical University in Szczecin, Powstancow Wielkopolskich 72, 70-111, Szczecin, Poland.
| | - Helena Masiuk
- Department of Medical Microbiology, Chair of Microbiology, Immunology and Laboratory Medicine, Pomeranian Medical University in Szczecin, Powstancow Wielkopolskich 72, 70-111, Szczecin, Poland
| | - Agata Pruss
- Department of Laboratory Medicine, Chair of Microbiology, Immunology and Laboratory Medicine, Pomeranian Medical University in Szczecin, Powstancow Wielkopolskich 72, 70-111, Szczecin, Poland
| | - Łukasz Łopusiewicz
- Center of Bioimmobilisation and Innovative Packaging Materials, Faculty of Food Sciences and Fisheries, West Pomeranian University of Technology Szczecin, Klemensa Janickiego 35, 71-270, Szczecin, Poland
| | - Monika Sienkiewicz
- Department of Pharmaceutical Microbiology and Microbiological Diagnostic, Medical University of Lodz, Muszynskiego 1, 90-151, Lodz, Poland
| | - Iwona Wojciechowska-Koszko
- Department of Diagnostic Immunology, Chair of Microbiology, Immunology and Laboratory Medicine, Pomeranian Medical University in Szczecin, Powstancow Wielkopolskich 72, 70-111, Szczecin, Poland
| | - Paulina Roszkowska
- Department of Diagnostic Immunology, Chair of Microbiology, Immunology and Laboratory Medicine, Pomeranian Medical University in Szczecin, Powstancow Wielkopolskich 72, 70-111, Szczecin, Poland
| | - Jacek Bania
- Department of Food Hygiene and Consumer Health Protection, Wroclaw University of Environmental and Life Sciences, C.K. Norwida 31, 50-375, Wroclaw, Poland
| | - Sebastian Guenther
- Pharmaceutical Biology, Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Straße 17, 17489, Greifswald, Germany
| | - Barbara Dołęgowska
- Department of Laboratory Medicine, Chair of Microbiology, Immunology and Laboratory Medicine, Pomeranian Medical University in Szczecin, Powstancow Wielkopolskich 72, 70-111, Szczecin, Poland
| |
Collapse
|
12
|
Raghuram V, Alexander AM, Loo HQ, Petit RA, Goldberg JB, Read TD. Species-Wide Phylogenomics of the Staphylococcus aureus Agr Operon Revealed Convergent Evolution of Frameshift Mutations. Microbiol Spectr 2022; 10:e0133421. [PMID: 35044202 PMCID: PMC8768832 DOI: 10.1128/spectrum.01334-21] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 01/03/2022] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus is a prominent nosocomial pathogen that causes several life-threatening diseases, such as pneumonia and bacteremia. S. aureus modulates the expression of its arsenal of virulence factors through sensing and integrating responses to environmental signals. The agr (accessory gene regulator) quorum sensing (QS) system is a major regulator of virulence phenotypes in S. aureus. There are four agr specificity groups each with a different autoinducer peptide sequence encoded by the agrD gene. Although agr is critical for the expression of many toxins, paradoxically, S. aureus strains often have nonfunctional agr activity due to loss-of-function mutations in the four-gene agr operon. To understand patterns in agr variability across S. aureus, we undertook a species-wide genomic investigation. We developed a software tool (AgrVATE; https://github.com/VishnuRaghuram94/AgrVATE) for typing and detecting frameshift mutations in the agr operon. In an analysis of over 40,000 S. aureus genomes, we showed a close association between agr type and S. aureus clonal complex. We also found a strong linkage between agrBDC alleles (encoding the peptidase, autoinducing peptide itself, and peptide sensor, respectively) but not agrA (encoding the response regulator). More than 5% of the genomes were found to have frameshift mutations in the agr operon. While 52% of these frameshifts occurred only once in the entire species, we observed cases where the recurring mutations evolved convergently across different clonal lineages with no evidence of long-term phylogenetic transmission, suggesting that strains with agr frameshifts were evolutionarily short-lived. Overall, genomic analysis of agr operon suggests evolution through multiple processes with functional consequences that are not fully understood. IMPORTANCE Staphylococcus aureus is a globally pervasive pathogen that produces a plethora of toxic molecules that can harm host immune cells. Production of these toxins is mainly controlled by an active agr quorum-sensing system, which senses and responds to bacterial cell density. However, there are many reports of S. aureus strains with genetic changes leading to impaired agr activity that are often found during chronic bloodstream infections and may be associated with increased disease severity. We developed an open-source software called AgrVATE to type agr systems and identify mutations. We used AgrVATE for a species-wide genomic survey of S. aureus, finding that more than 5% of strains in the public database had nonfunctional agr systems. We also provided new insights into the evolution of these genetic mutations in the agr system. Overall, this study contributes to our understanding of a common but relatively understudied means of virulence regulation in S. aureus.
Collapse
Affiliation(s)
- Vishnu Raghuram
- Microbiology and Molecular Genetics Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, USA
| | - Ashley M. Alexander
- Population Biology, Ecology, and Evolution Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, USA
| | - Hui Qi Loo
- Department of Biology, Emory University, Atlanta, Georgia, USA
| | - Robert A. Petit
- Division of Infectious Diseases, Department of Medicine, Emory University, Atlanta, Georgia, USA
| | - Joanna B. Goldberg
- Division of Pulmonary, Allergy and Immunology, Cystic Fibrosis, and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Timothy D. Read
- Division of Infectious Diseases, Department of Medicine, Emory University, Atlanta, Georgia, USA
| |
Collapse
|
13
|
Impact of agr Functionality on the Outcome of Patients with Methicillin-Susceptible Staphylococcus aureus Bacteremia. Microbiol Spectr 2021; 9:e0011621. [PMID: 34378959 PMCID: PMC8552762 DOI: 10.1128/spectrum.00116-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Dysfunctional accessory gene regulator (agr) is associated with unfavorable outcomes in invasive methicillin-resistant Staphylococcus aureus infections. However, it is unknown whether this association persists in methicillin-susceptible Staphylococcus aureus bacteremia (MSSA-B). This study evaluated the association between agr dysfunction and mortality in patients with MSSA-B. This retrospective cohort study included MSSA-B patients (≥15 years) enrolled from June 2014 to June 2019 and retrospectively collected their demographic and clinical information. Stored causative strains were measured for agr functionality by δ-hemolysin production assays. Among 244 MSSA-B patients, 91 (37.3%) and 153 (62.7%) had dysfunctional and functional agr MSSA-B, respectively. Ninety-day mortality occurred in 18.7% and 17.6% dysfunctional and functional groups, respectively (P = 0.97). Kaplan-Meier analysis showed that mortality due to dysfunctional agr MSSA-B was not significantly higher (P = 0.82). Age, sites, the severity of infection, and comorbidity adjusted hazard ratio (aHR) of the dysfunctional group for 90-day mortality was 1.303 (95% confidence interval [CI], 0.698 to 2.436, P = 0.41). Mortality due to MSSA-B with sequential organ failure assessment (SOFA) scores of 2 to 5 was significantly higher in the dysfunctional group (P = 0.03), and the dysfunctional agr aHR for 90-day mortality was 3.260 (95% CI, 1.050 to 10.118, P = 0.04). The agr dysfunction of causative organisms can have a significant effect on the outcomes of MSSA-B in patients with moderate severity (SOFA scores 2 to 5). IMPORTANCE Few studies have examined the association between methicillin-susceptible Staphylococcus aureus (MSSA) infection and accessory gene regulator (agr) functionality. We evaluated the association between agr dysfunction and mortality in patients with MSSA bacteremia. Dysfunctional agr is associated with lower survival in MSSA bacteremia patients with moderately severe sequential organ failure assessment (SOFA) scores of 2 to 5. We found that the agr functionality of causative organisms may have an effect on patients’ outcomes in MSSA like in methicillin-resistant S. aureus.
Collapse
|
14
|
Clinical and molecular characteristics of Staphylococcus aureus isolated from Chinese children: association among the agr groups and genotypes, virulence genes and disease types. World J Pediatr 2021; 17:180-188. [PMID: 33660136 DOI: 10.1007/s12519-021-00421-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 02/02/2021] [Indexed: 12/13/2022]
Abstract
BACKGROUND This study was aimed to investigate the clinical and molecular epidemiology of Staphylococcus aureus (S. aureus) isolated from Chinese children and determine the possible relationship among the accessory gene regulator (agr) groups and genotypes, as well as among the virulence genes and disease types. METHODS S. aureus strains were isolated from Beijing Children's Hospital between October 2017 and October 2019. The isolates and 19 virulence genes were characterized using multi-locus sequence typing, staphylococcal protein A (spa), staphylococcal cassette chromosome mec, and agr typing. RESULTS A total of 191 non-repetitive S. aureus clinical isolates were divided into 33 sequence types (STs), 18 clonal complexes (CCs), and 59 spa types. ST59 (39.8%), t437 (37.7%), and agr I (84.8%) were the predominant types. CC59, CC25, CC22, CC951, CC8, and CC398 belonged to agr I. CC5 and CC15 were assigned to agr II, and CC30 was characterized as agr III. CC121 was classified under agr IV. The eta, etb, and bbp genes were more prevalent in agr IV (P < 0.001 for each), while tst was more prevalent in agr group III compared to the other groups (P < 0.001). Nearly all isolates that harbored lukS/F-PV belonged to agr I (P = 0.005). However, the correlation between disease types and agr groups was not significant (P > 0.05). CONCLUSIONS An association among the agr groups and genotypes, as well as specific toxin genes, was observed among the S. aureus strains isolated from Chinese children. However, a statistical correlation was not found among the agr groups and disease types.
Collapse
|
15
|
Choi JH, Lee H, Choi EH. Antimicrobial Resistance and Molecular Analysis of Staphylococcus aureus in Staphylococcal Scalded Skin Syndrome among Children in Korea. J Korean Med Sci 2021; 36:e22. [PMID: 33463096 PMCID: PMC7813586 DOI: 10.3346/jkms.2021.36.e22] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 11/06/2020] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Staphylococcal scalded skin syndrome (SSSS) is a skin disease characterized by blistering and desquamation caused by exfoliative toxins (ETs) of Staphylococcus aureus (S. aureus). Although many countries show predominance of methicillin-susceptible S. aureus (MSSA), cases of methicillin-resistant S. aureus (MRSA) have been reported. METHODS Twenty-six children aged <15 years diagnosed with SSSS from January 2010 to December 2017 from three hospitals were included. S. aureus isolates from cases were analyzed for multilocus sequence types and ETs. Medical records were reviewed for clinical characteristics, treatment, and antimicrobial susceptibility patterns of S. aureus. RESULTS Among the 26 cases, mean age was 2.3 years. According to skin manifestations patients were classified as generalized (n = 10, 38.5%), intermediate (n = 11, 42.3%), and abortive (n = 5, 19.2%). Among all cases, 96.2% (25/26) were due to MRSA and the macrolide-resistance rate was 92.3% (24/26). ST89 (n = 21, 80.8%) was the most prevalent clone, followed by single clones of ST1, ST5, ST72, ST121, and ST1507. The eta gene was detected in one (3.8%) isolate which was MSSA. The etb gene was detected in 14 (53.8%) isolates, all of which were ST89. Nafcillin or first-generation cephalosporin was most commonly prescribed (n=20, 76.9%). Vancomycin was administered in four patients (15.4%) and clindamycin in nine patients (34.6%). Among MRSA cases, there was no difference in duration of treatment when comparing the use of antimicrobials to which the causative bacteria were susceptible or non-susceptible (9.75 vs. 8.07 days, P > 0.05). CONCLUSION S. aureus isolated from children with SSSS in Korea demonstrated a high prevalence of methicillin-resistant ST89 clones that harbored the etb gene. The predominance of MRSA suggests that antibiotics to which MRSA are susceptible may be considered for empirical antibiotic treatment in children with SSSS in Korea. Further studies on the role and effectiveness of systemic antibiotics in SSSS are warranted.
Collapse
Affiliation(s)
- Jae Hong Choi
- Department of Pediatrics, Jeju National University School of Medicine, Jeju, Korea
| | - Hyunju Lee
- Department of Pediatrics, Seoul National University Bundang Hospital, Seongnam, Korea
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea.
| | - Eun Hwa Choi
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea
| |
Collapse
|
16
|
Kim NH, Sung JY, Choi YJ, Choi SJ, Ahn S, Ji E, Kim M, Kim CJ, Song KH, Choe PG, Park WB, Kim ES, Park KU, Kim NJ, Oh MD, Kim HB. Toll-like receptor 2 downregulation and cytokine dysregulation predict mortality in patients with Staphylococcus aureus bacteremia. BMC Infect Dis 2020; 20:901. [PMID: 33256638 PMCID: PMC7706030 DOI: 10.1186/s12879-020-05641-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 11/19/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Staphylococcus aureus bacteremia (SAB) presents heterogeneously, owing to the differences in underlying host conditions and immune responses. Although Toll-like receptor 2 (TLR2) is important in recognizing S. aureus, its function during S. aureus infection remains controversial. We aimed to examine the association of TLR2 expression and associated cytokine responses with clinical SAB outcomes. METHODS Patients from a prospective SAB cohort at two tertiary-care medical centers were enrolled. Blood was sampled at several timepoints (≤5 d, 6-9 d, 10-13 d, 14-19 d, and ≥ 20 d) after SAB onset. TLR2 mRNA levels were determined via real-time PCR and serum tumor necrosis factor [TNF]-α, interleukin [IL]-6, and IL-10 levels were analyzed with multiplex-high-sensitivity electrochemiluminescent ELISA. RESULTS TLR2 levels varied among 59 SAB patients. On days 2-5, TLR2 levels were significantly higher in SAB survivors than in healthy controls (p = 0.040) and slightly but not significantly higher than non-survivors (p = 0.120), and SAB patients dying within 7 d had lower TLR2 levels than survivors (P = 0.077) although statistically insignificant. IL-6 and IL-10 levels were significantly higher in non-survivors than in survivors on days 2-5 post-bacteremia (P = 0.010 and P = 0.021, respectively), and those dying within 7 d of SAB (n = 3) displayed significantly higher IL-10/TNF-α ratios than the survivors did (P = 0.007). CONCLUSION TLR2 downregulation and IL-6 and IL-10 concentrations suggestive of immune dysregulation during early bacteremia may be associated with mortality from SAB. TLR2 expression levels and associated cytokine reactions during early-phase SAB may be potential prognostic factors in SAB, although larger studies are warranted.
Collapse
Affiliation(s)
- Nak-Hyun Kim
- Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, 173 Gumi-ro, Bundang-gu, Seongnam, 463-707, Republic of Korea
| | - Ji Yeon Sung
- Department of Laboratory Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Republic of Korea.,Present Address: Roche Korea, Seoul, Republic of Korea
| | - Yoon Jung Choi
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, 173 Gumi-ro, Bundang-gu, Seongnam, 463-707, Republic of Korea
| | - Su-Jin Choi
- Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Soyeon Ahn
- Medical Research Collaborating Center, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Eunjeong Ji
- Medical Research Collaborating Center, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Moonsuk Kim
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, 173 Gumi-ro, Bundang-gu, Seongnam, 463-707, Republic of Korea
| | - Chung Jong Kim
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, 173 Gumi-ro, Bundang-gu, Seongnam, 463-707, Republic of Korea.,Present Address: Department of Internal Medicine, Ewha Womans University, Seoul Hospital, Seoul, Republic of Korea
| | - Kyoung-Ho Song
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, 173 Gumi-ro, Bundang-gu, Seongnam, 463-707, Republic of Korea
| | - Pyoeng Gyun Choe
- Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Wan Beom Park
- Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Eu Suk Kim
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, 173 Gumi-ro, Bundang-gu, Seongnam, 463-707, Republic of Korea
| | - Kyoung Un Park
- Department of Laboratory Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Republic of Korea
| | - Nam-Joong Kim
- Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Myoung-Don Oh
- Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Hong Bin Kim
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, 173 Gumi-ro, Bundang-gu, Seongnam, 463-707, Republic of Korea.
| |
Collapse
|
17
|
Lee SO, Lee S, Lee JE, Song KH, Kang CK, Wi YM, San-Juan R, López-Cortés LE, Lacoma A, Prat C, Jang HC, Kim ES, Kim HB, Lee SH. Dysfunctional accessory gene regulator (agr) as a prognostic factor in invasive Staphylococcus aureus infection: a systematic review and meta-analysis. Sci Rep 2020; 10:20697. [PMID: 33244173 PMCID: PMC7691521 DOI: 10.1038/s41598-020-77729-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 11/17/2020] [Indexed: 12/14/2022] Open
Abstract
The accessory gene regulator (agr) locus of Staphylococcus aureus is a quorum-sensing virulence regulator. Although there are many studies concerning the effect of dysfunctional agr on the outcomes of S. aureus infection, there is no systematic review to date. We systematically searched for clinical studies reporting outcomes of invasive S. aureus infections and the proportion of dysfunctional agr among their causative strains, and we performed a meta-analysis to obtain estimates of the odds of outcomes of invasive S. aureus infection with dysfunctional versus functional agr. Of 289 articles identified by our research strategy, 20 studies were meta-analysed for crude analysis of the impact of dysfunctional agr on outcomes of invasive S. aureus infection. Dysfunctional agr was generally associated with unfavourable outcomes (OR 1.32, 95% CI 1.05–1.66), and the impact of dysfunctional agr on outcome was more prominent in invasive methicillin-resistant S. aureus (MRSA) infections (OR 1.54, CI 1.20–1.97). Nine studies were meta-analysed for the impact of dysfunctional agr on the 30-day mortality of invasive S. aureus infection. Invasive MRSA infection with dysfunctional agr exhibited higher 30-day mortality (OR 1.40, CI 1.03–1.90) than that with functional agr. On the other hand, invasive MSSA infection with dysfunctional agr exhibited lower 30-day mortality (OR 0.51, CI 0.27–0.95). In the post hoc subgroup analysis by the site of MRSA infection, dysfunctional agr was associated with higher 30-day mortality in MRSA pneumonia (OR 2.48, CI 1.17–5.25). The effect of dysfunctional agr on the outcome of invasive S. aureus infection may vary depending on various conditions, such as oxacillin susceptibility and the site of infection. Dysfunctional agr was generally associated with unfavourable clinical outcomes and its effect was prominent in MRSA and pneumonia. Dysfunctional agr may be applicable for outcome prediction in cases of invasive MRSA infection with hardly eradicable foci such as pneumonia.
Collapse
Affiliation(s)
- Soon Ok Lee
- Department of Internal Medicine, Pusan National University School of Medicine and Medical Research Institute, Pusan National University Hospital, 179 Gudeok-ro, Seo-gu, Busan, 49241, Republic of Korea
| | - Shinwon Lee
- Department of Internal Medicine, Pusan National University School of Medicine and Medical Research Institute, Pusan National University Hospital, 179 Gudeok-ro, Seo-gu, Busan, 49241, Republic of Korea.
| | - Jeong Eun Lee
- Department of Internal Medicine, Pusan National University School of Medicine and Medical Research Institute, Pusan National University Hospital, 179 Gudeok-ro, Seo-gu, Busan, 49241, Republic of Korea
| | - Kyoung-Ho Song
- Department of Internal Medicine, Seoul National University College of Medicine and Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Chang Kyung Kang
- Department of Internal Medicine, Seoul National University College of Medicine and Seoul National University Hospital, Seoul, Republic of Korea
| | - Yu Mi Wi
- Division of Infectious Diseases, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Republic of Korea
| | - Rafael San-Juan
- Unit of Infectious Diseases, University Hospital 12 de Octubre, Instituto de Investigación Hospital "12 de Octubre" (i+12), Universidad Complutense, Avenida de Córdoba, s/n, Madrid, Spain
| | - Luis E López-Cortés
- Unidad Clínica de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena/Departamento de Medicina, Universidad de Sevilla/Instituto de Biomedicina de Sevilla, Sevilla, Spain
| | - Alicia Lacoma
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Institut d' Investigació Germans Trias i Pujol, CIBER Enfermedades Respiratorias (CIBERES), Universitat Autònoma de Barcelona, Badalona, Spain
| | - Cristina Prat
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Institut d' Investigació Germans Trias i Pujol, CIBER Enfermedades Respiratorias (CIBERES), Universitat Autònoma de Barcelona, Badalona, Spain.,Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Hee-Chang Jang
- Department of Infectious Diseases, Chonnam National University Medical School, Gwang-ju, Republic of Korea
| | - Eu Suk Kim
- Department of Internal Medicine, Seoul National University College of Medicine and Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Hong Bin Kim
- Department of Internal Medicine, Seoul National University College of Medicine and Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Sun Hee Lee
- Department of Internal Medicine, Pusan National University School of Medicine and Medical Research Institute, Pusan National University Hospital, 179 Gudeok-ro, Seo-gu, Busan, 49241, Republic of Korea
| |
Collapse
|
18
|
Park KH, Jung M, Kim DY, Lee YM, Lee MS, Ryu BH, Hong SI, Hong KW, Bae IG, Cho OH. Effects of subinhibitory concentrations of chlorhexidine and mupirocin on biofilm formation in clinical meticillin-resistant Staphylococcus aureus. J Hosp Infect 2020; 106:295-302. [PMID: 32679053 DOI: 10.1016/j.jhin.2020.07.010] [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] [Received: 03/10/2020] [Accepted: 07/06/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUND The effects of subinhibitory concentrations (sub-MICs) of antibacterial agents on the biofilm-forming ability of Staphylococcus aureus require further study. AIM To investigate the effects of sub-MICs of chlorhexidine and mupirocin on biofilm formation in clinical meticillin-resistant Staphylococcus aureus (MRSA) isolates. METHODS MRSA isolates were collected from patients with bloodstream infections at a tertiary care hospital. The basal level of biofilm formation and biofilm induction by sub-MICs of chlorhexidine and mupirocin were evaluated by measuring biofilm mass stained with Crystal Violet. FINDINGS Of the 112 MRSA isolates tested, 63 (56.3%) and 44 (39.3%) belonged to sequence type (ST)5 and ST72 lineages, respectively, which are the predominant healthcare- and community-associated clones in South Korea. ST5 isolates were more likely to have chlorhexidine MIC ≥4 (73.0% vs 29.5%), resistance to mupirocin (23.8% vs 0%), agr dysfunction (73.0% vs 9.1%), and qacA/B gene (58.7% vs 2.3%) compared to ST72 isolates. The basal level of biofilm formation ability was frequently stronger in ST72 isolates compared to ST5 isolates (77.3% vs 12.7%). Sub-MICs of chlorhexidine and mupirocin promoted biofilm formation in 56.3% and 53.6%, respectively, of all isolates. Biofilm induction was more prevalent in ST5 isolates (85.7% for chlorhexidine, 69.8% for mupirocin) than in ST72 isolates (15.9% for chlorhexidine, 27.3% for mupirocin). CONCLUSION Sub-MICs of chlorhexidine and mupirocin promoted biofilm formation in half of the clinical MRSA isolates. Our results suggest that ST5 MRSA biofilm can be induced together with some other bacterial virulent factors following exposure to chlorhexidine, which might confer a survival advantage to this clone in the healthcare environment.
Collapse
Affiliation(s)
- K-H Park
- Division of Infectious Diseases, Department of Internal Medicine, Kyung Hee University Hospital, Kyung Hee University School of Medicine, Seoul, Republic of Korea
| | - M Jung
- Division of Infectious Diseases, Department of Internal Medicine, Kyung Hee University Hospital, Kyung Hee University School of Medicine, Seoul, Republic of Korea
| | - D Y Kim
- Division of Infectious Diseases, Department of Internal Medicine, Kyung Hee University Hospital, Kyung Hee University School of Medicine, Seoul, Republic of Korea
| | - Y-M Lee
- Division of Infectious Diseases, Department of Internal Medicine, Kyung Hee University Hospital, Kyung Hee University School of Medicine, Seoul, Republic of Korea
| | - M S Lee
- Division of Infectious Diseases, Department of Internal Medicine, Kyung Hee University Hospital, Kyung Hee University School of Medicine, Seoul, Republic of Korea
| | - B-H Ryu
- Department of Internal Medicine, Gyeongsang National University Changwon Hospital, Gyeongsang National University College of Medicine, Changwon, Republic of Korea
| | - S I Hong
- Department of Internal Medicine, Gyeongsang National University Changwon Hospital, Gyeongsang National University College of Medicine, Changwon, Republic of Korea
| | - K-W Hong
- Department of Internal Medicine, Gyeongsang National University Hospital, Gyeongsang National University College of Medicine, Jinju, Republic of Korea
| | - I-G Bae
- Department of Internal Medicine, Gyeongsang National University Hospital, Gyeongsang National University College of Medicine, Jinju, Republic of Korea; Gyeongsang Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, Republic of Korea
| | - O-H Cho
- Department of Internal Medicine, Gyeongsang National University Changwon Hospital, Gyeongsang National University College of Medicine, Changwon, Republic of Korea; Gyeongsang Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, Republic of Korea.
| |
Collapse
|
19
|
Antagonistic Effect of Colistin on Vancomycin Activity against Methicillin-Resistant Staphylococcus aureus in In Vitro and In Vivo Studies. Antimicrob Agents Chemother 2020; 64:AAC.01925-19. [PMID: 32041713 DOI: 10.1128/aac.01925-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 01/29/2020] [Indexed: 12/28/2022] Open
Abstract
As concerns arise that the vancomycin MIC of methicillin-resistant Staphylococcus aureus (MRSA) could be increased by concurrent colistin administration, we evaluated the effect of colistin on vancomycin efficacy against MRSA via in vitro and in vivo studies. Among MRSA blood isolates collected in a tertiary-care hospital, we selected representative strains from community-associated MRSA strains (CA-MRSA; ST72-MRSA-SCCmec IV) and hospital-acquired MRSA strains (HA-MRSA; ST5-MRSA-SCCmec II). USA CA-MRSA (USA300), HA-MRSA (USA100), N315 (New York/Japan clone), and a MRSA standard strain (ATCC 43300) were used for comparison. We performed checkerboard assays to identify changes in the vancomycin MIC of MRSA following colistin exposure and evaluated the effect of a vancomycin-colistin combination using time-kill assays. We also assessed the in vivo antagonistic effect by administering vancomycin, colistin, and a combination of these two in a neutropenic murine thigh infection model. In the checkerboard assays, vancomycin MICs of all MRSA strains except N315 were increased by from 0.25 to 0.75 μg/ml following colistin exposure. However, the time-kill assays indicated antagonism only against ST5-MRSA and USA100, when the vancomycin concentration was twice the MIC. In the murine thigh infection model with ST5-MRSA and USA100, vancomycin monotherapy reduced the number of CFU/muscle >1 log10 compared to a combination treatment after 24 h in ST5-MRSA, indicating an antagonistic effect of colistin on vancomycin treatment. This study suggests that exposure to colistin may reduce the susceptibility to vancomycin of certain MRSA strains. Combination therapy with vancomycin and colistin for multidrug-resistant pathogens might result in treatment failure for concurrent MRSA infection.
Collapse
|
20
|
Mun YS, Hwang YJ. Novel spa and Multi-Locus Sequence Types (MLST) of Staphylococcus Aureus Samples Isolated from Clinical Specimens in Korean. Antibiotics (Basel) 2019; 8:antibiotics8040202. [PMID: 31671880 PMCID: PMC6963223 DOI: 10.3390/antibiotics8040202] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 10/21/2019] [Accepted: 10/22/2019] [Indexed: 12/24/2022] Open
Abstract
Staphylococcus aureus bacteremia is one of the most frequent and severe bacterial infections worldwide. The increased incidence of S. aureus infections with a diverse pattern of S. aureus protein A (spa) types across different geographic regions is a global challenge. This study investigated a novel spa type of methicillin-resistant S. aureus in a clinically isolated specimen. A total of 109 clinical S. aureus samples were subjected to 19 sets of antimicrobial susceptibility testing using the Kirby-Bauer disk diffusion method. Molecular typing was performed with S. aureus protein A (spa) and multi-locus sequence types (MLST) via polymerase chain reaction and sequencing. The methicillin-resistant S. aureus samples in our study accounted for 55.05% (60/109) of the total. A novel spa type was detected in five (5/60) strains. This gh22 isolate was identified in antimicrobial susceptibility tests of 15 kinds of antibiotics. Antibiotic resistance genes included mecA, TEM, aac(6')-aph(2"), ermA, and tetM. Eleven S. aureus samples were classified as t2460, t338, t324, t693, five unknown spa types (new spa types), and undefined MLST (novel MLST). We report a high prevalence rate of t2460 methicillin-resistant S. aureus samples in our country. Additionally, novel spa gh22, MLST ST4613, and clonal compact CC5-type strains (T1:M1:B1:B1:M1:E1:K1, r26:r17:r34:r34:r17:r13:r16, mlst;1:4:1:4:559:495:10) showing multidrug resistance were identified among S. aureus samples.
Collapse
Affiliation(s)
- Yae Sung Mun
- Department of Life science, College of Bio-nano technology, Gachon University, 191, Hambangmoe-ro, Yeonsu-gu, Incheon 21936, Korea.
| | - You Jin Hwang
- Department of Life science, College of Bio-nano technology, Gachon University, 191, Hambangmoe-ro, Yeonsu-gu, Incheon 21936, Korea.
- Department of Health Sciences and Technology, GAIHST, Gachon University, Incheon 21999, Korea.
- Department of Biomedical Engineering, College of Health Science, Gachon University, 191, Hambangmoe-ro, Yeonsu-gu, Incheon 21936, Korea.
| |
Collapse
|
21
|
Quorum Sensing, Virulence, and Antibiotic Resistance of USA100 Methicillin-Resistant Staphylococcus aureus Isolates. mSphere 2019; 4:4/4/e00553-19. [PMID: 31413175 PMCID: PMC6695519 DOI: 10.1128/msphere.00553-19] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) infections impact all patient populations both in the community and in health care settings. Despite advances in our knowledge of MRSA virulence, little is known about the regulatory mechanisms of USA100 health care-associated MRSA isolates, which are the second most frequently identified MRSA isolates found in all infections. This work focused on the contribution of the USA100 agr type II quorum-sensing system to virulence and antibiotic resistance. From a MRSA strain collection, we selected 16 representative USA100 isolates, constructed mutants with Δagr mutations, and characterized selected strain pairs for virulence factor expression, murine skin infection, and antibiotic resistance. For each strain pair, hemolysis and extracellular protease expression were significantly greater in the wild-type (WT) strains than in the Δagr mutants. Similarly, mice challenged with the WT strains had larger areas of dermonecrosis and greater weight loss than those challenged with the Δagr mutants, demonstrating that the USA100 agr system regulates virulence. Although USA100 isolates exhibit a high level of antibiotic resistance, the WT and Δagr strain pairs showed no difference in MICs by MIC testing. However, in the presence of a sub-MIC of vancomycin, most of the USA100 Δagr mutants exhibited slower growth than the WT isolates, and a couple of the Δagr mutants also grew more slowly in the presence of a sub-MIC of cefoxitin. Altogether, our findings demonstrate that the USA100 agr system is a critical regulator of virulence, and it may have a contribution to the optimal survival of these MRSA strains in the presence of antibiotics.IMPORTANCE USA100 health care-associated MRSA isolates are highly antibiotic resistant and can cause invasive disease across all patient populations. Even though USA100 strains are some of the most frequently identified causes of infections, little is known about virulence regulation in these isolates. Our study demonstrates that the USA100 agr quorum-sensing system is important for the control of toxin and exoenzyme production and that the agr system has a key role in skin infection. In some USA100 isolates, the agr system is important for growth in the presence of low levels of antibiotics. Altogether, our findings demonstrate that the USA100 agr system is a critical regulator of virulence and that it may make a contribution to the optimal survival of these MRSA strains in the presence of antibiotics.
Collapse
|
22
|
Clinical and Molecular Characteristics of qacA- and qacB-Positive Methicillin-Resistant Staphylococcus aureus Causing Bloodstream Infections. Antimicrob Agents Chemother 2019; 63:AAC.02157-18. [PMID: 30718251 DOI: 10.1128/aac.02157-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 01/27/2019] [Indexed: 11/20/2022] Open
Abstract
The increasing use of chlorhexidine for methicillin-resistant Staphylococcus aureus (MRSA) decolonization has raised concerns about the emergence of resistance to these agents. However, the clinical significance of MRSA positive for the qacA and qacB chlorhexidine tolerance genes has not been established. We investigated the clinical features and predictive factors of MRSA bloodstream infection (BSI) isolates, caused by qacA- and qacB-positive MRSA, from 2010 to 2016 at a tertiary hospital in South Korea. A total of 246 MRSA BSI isolates were included; 71 (28.9%) isolates carried qacA/B The annual frequency of qacA- and qacB-positive MRSA bacteremia did not change significantly over the study period. Patients infected with qacA- and qacB-positive MRSA had common risk factors for health care-associated infections, including prior antibiotic use, central venous catheterization in situ, intensive care unit-acquired bacteremia, and nosocomial infection. The qacA- and qacB-positive isolates were also associated with an increasing chlorhexidine MIC and resistance to non-β-lactam antibiotics. The qacA- and qacB-positive isolates were more likely to belong to sequence type 5 (ST5), which is a common health care-associated MRSA strain in South Korea. In multivariable analyses, qacA- and qacB-positive MRSA isolates were found to be associated with agr dysfunction (adjusted odds ratio [aOR], 6.45; 95% confidence interval [CI], 2.59 to 16.10), ST5 MRSA strain (aOR, 4.96; 95% CI, 1.85 to 13.26), nosocomial infection (aOR, 4.88; 95% CI, 2.20 to 10.83), and antibiotic use within the previous 3 months (aOR, 2.59; 95% CI, 1.20 to 5.59). These findings suggest that the microbiological features of qacA and qacB carriage provide a selective advantage for specific MRSA strains in hospital environments.
Collapse
|
23
|
Yang J, Qiu L, Huang Y, Chen Y, Rao S, Ruan W, Zhao G, Ye L. [The inhibition of accessory gene regulator C specific binding peptides on biofilm formation of Staphylococcus epidermidis on the surface of polyvinyl chloride in vitro]. ZHONGGUO XIU FU CHONG JIAN WAI KE ZA ZHI = ZHONGGUO XIUFU CHONGJIAN WAIKE ZAZHI = CHINESE JOURNAL OF REPARATIVE AND RECONSTRUCTIVE SURGERY 2019; 33:349-355. [PMID: 30874395 PMCID: PMC8337929 DOI: 10.7507/1002-1892.201806110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 01/15/2019] [Indexed: 11/03/2022]
Abstract
Objective To investigate the effect of accessory gene regulator C (agr C) specific binding peptides (named N1) on the biofilm formation of Staphylococcus epidermidis on the surface of polyvinyl chloride (PVC) materials in vitro. Methods Firstly, the two strains (ATCC35984, ATCC12228) were cultured with N1 at concentrations of 100, 200, 400, 800, and 1 600 μg/mL, respectively. The control group was cultured with agrC specific binding unrelated peptides (named N0) at the same concentrations and the absorbance ( A) value was measured after 24 hours to determine the optimal bacteriostatic concentration of N1. The two strains were cultured with N1 and N0 of the optimal concentration, respectively. The A values were measured at 6, 12, 18, 24, 30, and 48 hours to observe the effect of N1 on the biofilm formation ability of Staphylococcus epidermidis. On this basis, the surface structure of the biofilm on the surface of PVC material was observed by scanning electron microscopy after 6, 12, 18, 24, and 30 hours of incubation with PVC material sheet. The thickness of the biofilm was observed by laser confocal microscopy after 6, 12, 18, and 24 hours of incubation with ATCC35984 strain. Results The optimal bacteriostatic concentration of N1 was 800 μg/mL. ATCC 12228 strain did not form obvious biofilm after being cultured with N1 and N0. When ATCC35984 strain was cultured with N1 and N0 for 12 hours, the difference in biofilm formation ability between groups N1 and N0 was statistically significant ( P<0.05), but there was no significant difference at 6, 18, 24, 30, and 48 hours ( P>0.05). Scanning electron microscopy examination showed that mature biofilm structure was observed in ATCC35984 strain and was not observed in ATCC12228 strain. Laser confocal microscopy observation showed that the number of bacteria in the group N1 was significantly lower than that in the group N0 at 12 hours, and the most of bacteria were dead bacteria. There was no significant difference in the number of bacteria at 6, 18, and 24 hours, and the most of them were live bacteria. The biofilm thickness of group N1 was significantly lower than that of group N0 at 12 and 18 hours ( P<0.05). Conclusion The intensity of N1 inhibiting the formation of Staphylococcus epidermidis biofilm is dose-dependent. During the aggregation period, N1 can inhibit the biofilm formation by hindering the bacterial growth and aggregation. The inhibition effect on mature biofilm is not obvious.
Collapse
Affiliation(s)
- Jichen Yang
- Department of Thoracic Surgery, the Third Affiliated Hospital of Kunming Medical University, Tumor Hospital of Yunnan Province, Kunming Yunnan, 650118, P.R.China
| | - Liangting Qiu
- Department of Thoracic Surgery, the Third Affiliated Hospital of Kunming Medical University, Tumor Hospital of Yunnan Province, Kunming Yunnan, 650118, P.R.China
| | - Yunchao Huang
- Department of Thoracic Surgery, the Third Affiliated Hospital of Kunming Medical University, Tumor Hospital of Yunnan Province, Kunming Yunnan, 650118, P.R.China
| | - Ya Chen
- Department of Thoracic Surgery, the Third Affiliated Hospital of Kunming Medical University, Tumor Hospital of Yunnan Province, Kunming Yunnan, 650118, P.R.China
| | - Sunyin Rao
- Department of Thoracic Surgery, the Third Affiliated Hospital of Kunming Medical University, Tumor Hospital of Yunnan Province, Kunming Yunnan, 650118, P.R.China
| | - Wenpeng Ruan
- Department of Thoracic Surgery, the Third Affiliated Hospital of Kunming Medical University, Tumor Hospital of Yunnan Province, Kunming Yunnan, 650118, P.R.China
| | - Guangqiang Zhao
- Department of Thoracic Surgery, the Third Affiliated Hospital of Kunming Medical University, Tumor Hospital of Yunnan Province, Kunming Yunnan, 650118, P.R.China
| | - Lianhua Ye
- Department of Thoracic Surgery, the Third Affiliated Hospital of Kunming Medical University, Tumor Hospital of Yunnan Province, Kunming Yunnan, 650118,
| |
Collapse
|
24
|
Bae E, Kim CK, Jang JH, Sung H, Choi Y, Kim MN. Impact of Community-Onset Methicillin-Resistant Staphylococcus aureus on Staphylococcus aureus Bacteremia in a Central Korea Veterans Health Service Hospital. Ann Lab Med 2019; 39:158-166. [PMID: 30430778 PMCID: PMC6240515 DOI: 10.3343/alm.2019.39.2.158] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 05/18/2018] [Accepted: 10/04/2018] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND No study has examined the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) bacteremia in Korean veterans' hospitals. We investigated the microbiological and clinical epidemiology of S. aureus bacteremia at the central Veterans Health Services (VHS) hospital in Korea. METHODS Patients with S. aureus bacteremia were consecutively enrolled from February to August 2015. Bacteremia was classified as hospital-acquired (HA), community-onset healthcare-associated (COHA), or community-acquired (CA). MRSA bacteremia risk factors were analyzed. Species identification, antimicrobial susceptibility, and presence of luk and tst were tested. Staphylococcal cassette chromosome mec (SCCmec) typing, spa sequence typing agr polymorphism typing, and multilocus sequence typing were performed. Biofilm production and δ-hemolysin activity were measured to determine agr function. RESULTS In total, 60 patients were enrolled (30 HA, 23 COHA, and seven CA bacteremia); 44 (73.3%) had MRSA bacteremia (26 HA, 16 COHA, and two CA). MRSA bacteremia occurred more frequently in non-CA patients and those who had received antibiotic treatment within the past month (P<0.05). The major MRSA strains comprised 24 ST5-agr2-SCCmecII, 11 ST72-agr 1-SCCmecIV, and five ST8-agr1-SCCmecIV strains. Of 26 agr2-SCCmecII strains, including two MSSA strains, 25 were multidrug-resistant, 18 were tst-positive, and 13 were agr-defective, whereas only five of the 18 agr1-SCCmecIV strains were multidrug-resistant, and all were tst-negative and agr-intact. agr1-SCCmecIV and ST8-agr1-SCCmecIV strains were more likely than agr2-SCCmecII strains to be COHA. CONCLUSIONS MRSA was highly prevalent in both COHA and HA bacteremia. The introduction of virulent CA-MRSA strains may be an important cause of increased HA-MRSA bacteremia in VHS hospitals.
Collapse
Affiliation(s)
- Eunsin Bae
- Department of Laboratory Medicine, Veterans Health Service Medical Center, Seoul, Korea
| | - Choon Kwan Kim
- Department of Internal Medicine, Veterans Health Service Medical Center, Seoul, Korea
| | - Jung Hyun Jang
- Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea
| | - Heungsup Sung
- Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea
| | - YounMi Choi
- Department of Laboratory Medicine, Veterans Health Service Medical Center, Seoul, Korea.
| | - Mi Na Kim
- Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
| |
Collapse
|
25
|
Geslain G, Bourgade C, Chomton M, Le Bourgeois F. Methicillin-sensible Staphylococcus aureus causing endocarditis, with cerebral and orthopaedic complications, in a 17-month-old child with no risk factor. BMJ Case Rep 2018; 2018:bcr-2018-226388. [PMID: 30317206 DOI: 10.1136/bcr-2018-226388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
We report a case of Staphylococcus aureus endocarditis, with large vegetation, in a 17-month-old male infant, complicated with meningitis, ischaemic strokes and osteoarthritis leading to haemorrhagic stroke by aneurysm rupture. He did not present any risk factor for endocarditis. The final course was favourable through, after valve replacement. The strain was sensible to methicillin and belongs to complex clonal 398, with accessory gene regulator I. We did not found immunodeficiency.
Collapse
Affiliation(s)
- Guillaume Geslain
- Paediatric Mobile Emergency and Intensive Care Units, Hopital Universitaire Robert-Debre, Paris, France.,Hopital Universitaire Robert-Debre, Department of Microbiology, Paris, France
| | - Clara Bourgade
- Department of Pediatric Cardiology, Hopital Universitaire Robert-Debre, Paris, France
| | - Maryline Chomton
- Paediatric Mobile Emergency and Intensive Care Units, Hopital Universitaire Robert-Debre, Paris, France
| | - Fleur Le Bourgeois
- Paediatric Mobile Emergency and Intensive Care Units, Hopital Universitaire Robert-Debre, Paris, France
| |
Collapse
|
26
|
Krishna A, Holden MTG, Peacock SJ, Edwards AM, Wigneshweraraj S. Naturally occurring polymorphisms in the virulence regulator Rsp modulate Staphylococcus aureus survival in blood and antibiotic susceptibility. MICROBIOLOGY (READING, ENGLAND) 2018; 164:1189-1195. [PMID: 30028663 PMCID: PMC6230762 DOI: 10.1099/mic.0.000695] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 07/03/2018] [Indexed: 01/20/2023]
Abstract
Nasal colonization by the pathogen Staphylococcus aureus is a risk factor for subsequent infection. Loss of function mutations in the gene encoding the virulence regulator Rsp are associated with the transition of S. aureus from a colonizing isolate to one that causes bacteraemia. Here, we report the identification of several novel activity-altering mutations in rsp detected in clinical isolates, including for the first time, mutations that enhance agr operon activity. We assessed how these mutations affected infection-relevant phenotypes and found loss and enhancement of function mutations to have contrasting effects on S. aureus survival in blood and antibiotic susceptibility. These findings add to the growing body of evidence that suggests S. aureus 'trades off' virulence for the acquisition of traits that benefit survival in the host, and indicates that infection severity and treatment options can be significantly affected by mutations in the virulence regulator rsp.
Collapse
Affiliation(s)
- Aishwarya Krishna
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Matthew T. G. Holden
- Wellcome Trust Sanger Institute, Hinxton, UK
- School of Medicine, University of St Andrews, St Andrews, UK
| | - Sharon J. Peacock
- Wellcome Trust Sanger Institute, Hinxton, UK
- London School of Hygiene and Tropical Medicine, London, UK
| | - Andrew M. Edwards
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | | |
Collapse
|
27
|
Turkey AM, Barzani KK, Suleiman AAJ, Abed JJ. Molecular assessment of accessory gene regulator ( agr) quorum sensing system in biofilm forming Staphylococcus aureus and study of the effect of silver nanoparticles on agr system. IRANIAN JOURNAL OF MICROBIOLOGY 2018; 10:14-21. [PMID: 29922414 PMCID: PMC6004638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
BACKGROUND AND OBJECTIVES Staphylococcus aureus is an opportunistic human pathogen that causes a variety of diseases. Staphylococcal biofilms are a source of chronic and continual infections. This study was conducted to estimate the distribution of agr among different isolates of S. aureus and their relationship with biofilm. Also, it was aimed to check the association of operon agr with virulence factors (seb, eta, spa and tst v8) and study the effect of biosynthesis silver nanoparticles on the function of the agr system. MATERIALS AND METHODS Out of 580 clinical specimens, 100 S. aureus isolates were isolated and identified based on cultural, morphological, and different biochemical tests, in addition to molecular identification using PCR with specific primer 16SrRNA. For biofilm detection, the fungi synthesized silver nanoparticles were used to check its effect on agr system. RESULTS The biofilm producer among S. aureus was 61% and non-biofilm producer isolates were 39%. It was found that the total number of agr - bearing isolates was 31 (50.82%), with a significant difference in the distribution percentage of virulence factors genes in isolates of biofilm-forming S. aureus carried agr. The results also revealed a relationship between the agr-quorum sensing system and the prevalence of virulence genes in the isolated S. aureus. Silver nanoparticles (AgNPs) were synthesized by Agaricus compestris, and it was found that it activates the agr system in 31 (100%) of biofilm-forming and carrying operon agr after treatment with sub-MIC of AgNPs. CONCLUSION The findings of this study revealed that not all isolates of S. aureus have agr system. Also, it was found that AgNPs have a positive effect on bacterial virulence factors production and could be used for treatment or in cooperation with antibiotics to decrease resistance.
Collapse
Affiliation(s)
| | | | - Ahmed Abdul Jabbar Suleiman
- Biology Department, College of Sciences, University of Anbar, Ramadi, Iraq,Corresponding author: Ahmed Abdul Jabbar Suleiman, PhD, Biology Department, College of Sciences, University of Anbar, Ramadi, Iraq. Tel: +9647904774532, Fax: +9647704341535,
| | - Jenan Jameel Abed
- Biology Department, College of Sciences, University of Anbar, Ramadi, Iraq
| |
Collapse
|
28
|
Cho OH, Park KH, Song JY, Hong JM, Kim T, Hong SI, Kim S, Bae IG. Prevalence and Microbiological Characteristics of qacA/B-Positive Methicillin-Resistant Staphylococcus aureus Isolates in a Surgical Intensive Care Unit. Microb Drug Resist 2017; 24:283-289. [PMID: 28799881 DOI: 10.1089/mdr.2017.0072] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The increasing use of chlorhexidine for methicillin-resistant Staphylococcus aureus (MRSA) decolonization has raised concerns about the emergence of resistance to or tolerance of this antiseptic. We examined the frequency and characteristics of qacA/B chlorhexidine tolerance genes among MRSA isolates in a surgical intensive care unit (ICU) where MRSA-colonized patients are decolonized by chlorhexidine bathing. The MRSA isolates were evaluated for chlorhexidine susceptibility, mupirocin resistance, molecular typing, agr functionality, and the heterogeneous vancomycin-intermediate S. aureus (hVISA) phenotype according to the presence of the qacA/B genes. Overall, 119 MRSA isolates were obtained from active surveillance cultures (93, 78.2%) and clinical cultures (26, 21.8%) between 2012 and 2014. Among these isolates, 39 (32.8%) carried the qacA/B genes, and 23 (19.3%) exhibited mupirocin resistance. Most qacA/B-positive isolates (36/39, 92.3%) were identified as ST5-SCCmecII (69.2%) and ST239-SCCmecIII (23.1%), which are common healthcare-associated (HA)-MRSA strains in Korea. Multivariate analysis found that qacA/B-positive MRSA isolates were associated with agr dysfunction (OR, 4.87; 95% CI, 1.71-13.87) and the hVISA phenotype (OR, 4.09; 95% CI, 1.48-11.34). In conclusion, our study showed that qacA/B carriage was common among MRSA isolates in an ICU where chlorhexidine is commonly used for decolonization. qacA/B carriage was significantly associated with agr dysfunction and the hVISA phenotype. These features may confer a selective advantage on HA-MRSA strains, including ST5-SCCmecII and ST239-SCCmecIII, in the ICU setting.
Collapse
Affiliation(s)
- Oh-Hyun Cho
- 1 Department of Internal Medicine, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine , Jinju, Republic of Korea
| | - Ki-Ho Park
- 2 Division of Infectious Diseases, Department of Internal Medicine, Kyung Hee University Hospital, Kyung Hee University School of Medicine , Seoul, Republic of Korea
| | - Ji Young Song
- 1 Department of Internal Medicine, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine , Jinju, Republic of Korea
| | - Jeong Min Hong
- 1 Department of Internal Medicine, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine , Jinju, Republic of Korea
| | - Taeeun Kim
- 1 Department of Internal Medicine, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine , Jinju, Republic of Korea
| | - Sun In Hong
- 3 Department of Internal Medicine, Gyeongsang National University Changwon Hospital , Changwon, Republic of Korea
| | - Sunjoo Kim
- 4 Department of Laboratory Medicine, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine , Jinju, Republic of Korea.,5 Gyeongsang Institute of Health Sciences, Gyeongsang National University School of Medicine , Jinju, Republic of Korea
| | - In-Gyu Bae
- 1 Department of Internal Medicine, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine , Jinju, Republic of Korea.,5 Gyeongsang Institute of Health Sciences, Gyeongsang National University School of Medicine , Jinju, Republic of Korea
| |
Collapse
|
29
|
Vubil D, Garrine M, Ruffing U, Acácio S, Sigaúque B, Alonso PL, von Müller L, Herrmann M, Mandomando I. Molecular Characterization of Community Acquired Staphylococcus aureus Bacteremia in Young Children in Southern Mozambique, 2001-2009. Front Microbiol 2017; 8:730. [PMID: 28522992 PMCID: PMC5415612 DOI: 10.3389/fmicb.2017.00730] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 04/07/2017] [Indexed: 01/15/2023] Open
Abstract
Background: The emergence of community-acquired Staphylococcus aureus infections is increasingly recognized as life threating problem worldwide. In Manhiça district, southern Mozambique, S. aureus is the leading cause of community-acquired bacteremia in neonates. Methods: Eighty-four S. aureus isolates from children less than 5 years admitted to Manhiça District Hospital from 2001 to 2009 were randomly selected and genetically characterized by DNA microarray and spa typing. Antimicrobial susceptibility was determined by VITEK 2. Results: Thirty-eight different spa types and 14 clonal complexes (CC) were identified. Spa-type t084 (n = 10; 12%) was the most predominant while CC8 (n = 18; 21%) and CC15 (n = 14; 16%) were the most frequent CCs. Mortality tended to be higher among children infected with CC45 (33.3%, 1/3) and CC8 (27.8%, 5/18). The majority of isolates possessed the accessory gene regulator I (45%) and belonged to either capsule type 8 (52%) or 5 (47%). Panton valentine leukocidin (PVL) encoding genes were detected in 30%. Antibiotic resistance was high for penicillin (89%), tetracycline (59%) and Trimethoprim Sulfamethoxazole (36%) while MRSA was uncommon (8%). Conclusions: Although MRSA were uncommon, we found high genetic diversity of methicillin susceptible S. aureus causing bacteremia in Mozambican children, associated with high resistance to the most available antibiotics in this community. Some CCs are likely to be more lethal indicating the need for prompt recognition and appropriate treatment.
Collapse
Affiliation(s)
- Delfino Vubil
- Centro de Investigação em Saúde de Manhiça (CISM)Maputo, Mozambique
| | | | - Ulla Ruffing
- Institute of Medical Microbiology and Hygiene, University of SaarlandHomburg, Germany
| | - Sozinho Acácio
- Centro de Investigação em Saúde de Manhiça (CISM)Maputo, Mozambique.,Instituto Nacional de Saúde (INS), Ministério da SaúdeMaputo, Mozambique
| | - Betuel Sigaúque
- Centro de Investigação em Saúde de Manhiça (CISM)Maputo, Mozambique.,Instituto Nacional de Saúde (INS), Ministério da SaúdeMaputo, Mozambique
| | - Pedro L Alonso
- Centro de Investigação em Saúde de Manhiça (CISM)Maputo, Mozambique.,Barcelona Institute of Global HealthBarcelona, Spain
| | - Lutz von Müller
- Institute of Medical Microbiology and Hygiene, University of SaarlandHomburg, Germany
| | - Mathias Herrmann
- Institute of Medical Microbiology and Hygiene, University of SaarlandHomburg, Germany
| | - Inácio Mandomando
- Centro de Investigação em Saúde de Manhiça (CISM)Maputo, Mozambique.,Instituto Nacional de Saúde (INS), Ministério da SaúdeMaputo, Mozambique
| |
Collapse
|
30
|
Gomes-Fernandes M, Laabei M, Pagan N, Hidalgo J, Molinos S, Villar Hernandez R, Domínguez-Villanueva D, Jenkins ATA, Lacoma A, Prat C. Accessory gene regulator (Agr) functionality in Staphylococcus aureus derived from lower respiratory tract infections. PLoS One 2017; 12:e0175552. [PMID: 28410390 PMCID: PMC5391941 DOI: 10.1371/journal.pone.0175552] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 03/28/2017] [Indexed: 01/09/2023] Open
Abstract
Objective Characterization of Staphylococcus aureus clinical isolates derived from lower respiratory tract infections (LRTIs), and correlation between the functionality of the accessory gene regulator (Agr) and genotypic and phenotypic characteristics, clinical variables and clinical outcome. Methods S aureus isolates derived from LRTIs and control groups (nasal carriage and bacteraemia) were genotyped using StaphyType DNA microarray. Agr activity was evaluated using the CAMP synergistic haemolysis assay and the Vesicle Lysis Test (VLT). Discordant strains were analysed by quantitative reverse-transcriptase real-time PCR (qRT-PCR). Results Agr was functional in 79.7% and 84.5% of strains according to the CAMP and VLT assays respectively. Higher concordance with RNAIII expression measured by qRT-PCR was observed with the VLT assay (76.2%) compared with the CAMP assay (23.8%). No statistically significant differences were observed in Agr functionality between the study groups, nor the phenotypical/genotypical bacterial characteristics. No association between increased mortality/respiratory complications and Agr function was observed. Conclusions Agr activity was high (82.2%) in isolates from LRTIs suggesting the importance of this global regulator in lower respiratory tract colonisation and infection. However, equally high Agr activity was observed in isolates derived from nasal carriage and bacteraemia, contradictory to previous observations. Agr functionality measured by the VLT assay was superior to CAMP assay.
Collapse
Affiliation(s)
- Meissiner Gomes-Fernandes
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Institut d’ Investigació Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
- CAPES Foundation, Ministry of Education of Brazil, Brasília, Brazil
| | - Maisem Laabei
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Institut d’ Investigació Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Natalia Pagan
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Institut d’ Investigació Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Jessica Hidalgo
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Institut d’ Investigació Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Sònia Molinos
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Institut d’ Investigació Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Raquel Villar Hernandez
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Institut d’ Investigació Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Dídac Domínguez-Villanueva
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Institut d’ Investigació Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | | | - Alicia Lacoma
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Institut d’ Investigació Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
- CIBER Enfermedades Respiratorias, CIBER, Instituto de Salud Carlos III, Badalona, Spain
| | - Cristina Prat
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Institut d’ Investigació Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
- CIBER Enfermedades Respiratorias, CIBER, Instituto de Salud Carlos III, Badalona, Spain
- * E-mail:
| |
Collapse
|
31
|
Kim T, Kim ES, Park SY, Sung H, Kim MN, Kim SH, Lee SO, Choi SH, Jeong JY, Woo JH, Chong YP, Kim YS. Phenotypic changes of methicillin-resistant Staphylococcus aureus during vancomycin therapy for persistent bacteraemia and related clinical outcome. Eur J Clin Microbiol Infect Dis 2017; 36:1473-1481. [PMID: 28337607 DOI: 10.1007/s10096-017-2956-1] [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] [Received: 12/16/2016] [Accepted: 03/02/2017] [Indexed: 12/13/2022]
Abstract
Persistent bacteraemia (PB) due to methicillin-resistant Staphylococcus aureus (MRSA) that fails to respond to glycopeptide therapy is a well-documented clinical problem. There are limited data on changes in agr functionality, vancomycin susceptibility and heteroresistance during MRSA PB. Thus, the frequency of these changes and their clinical significance remain unclear. Only patients with MRSA PB (≥7 days) from a prospective cohort of S. aureus bacteraemia were included. We collected isogenic paired strains and compared vancomycin MIC, vancomycin heteroresistance, and agr functionality between initial and final blood isolates. We also assessed the clinical outcome. A total of 49 patients had MRSA PB over 22 months. Bacteraemia persisted for a median of 13 days and most patients (98%) received glycopeptide as initial therapy. Among 49 isogenic pairs, only one pair showed a vancomycin MIC increase ≥2-fold by broth microdilution method, and only seven (14%) by E-test. Significant portions of initial isolates had vancomycin heteroresistance (49%) and agr dysfunction (76%). Development of vancomycin heteroresistance during PB occurred in four (16%) among 25 initial vancomycin-susceptible isolates, and acquisition of agr dysfunction occurred in two (16%) among 12 initial agr-functional isolates. Changes in the opposite direction occasionally occurred. These phenotypic changes during PB were not associated with mortality, whereas agr dysfunction of the initial isolates was significantly associated with mortality. During MRSA PB, phenotypic changes of MRSA isolates occurred occasionally under prolonged vancomycin exposure but were not significantly associated with clinical outcome. In contrast, initial agr dysfunction could be a predictor for mortality in MRSA PB.
Collapse
Affiliation(s)
- T Kim
- Division of Infectious Diseases, Department of Internal Medicine, Gyeongsang National University Hospital, 79, Gangnam-ro, Jinju, Gyeongsangnam-do, 52727, Republic of Korea
| | - E S Kim
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro43-gil, Songpa-gu, Seoul, 138-736, Republic of Korea
| | - S Y Park
- Division of Infectious Diseases, Department of Internal Medicine, Soonchunhyang University Seoul Hospital, Soonchunhyang University College of Medicine, Seoul, Republic of Korea
| | - H Sung
- Department of Laboratory Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - M-N Kim
- Department of Laboratory Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - S-H Kim
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro43-gil, Songpa-gu, Seoul, 138-736, Republic of Korea
| | - S-O Lee
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro43-gil, Songpa-gu, Seoul, 138-736, Republic of Korea
| | - S-H Choi
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro43-gil, Songpa-gu, Seoul, 138-736, Republic of Korea
| | - J-Y Jeong
- Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - J H Woo
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro43-gil, Songpa-gu, Seoul, 138-736, Republic of Korea
| | - Y P Chong
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro43-gil, Songpa-gu, Seoul, 138-736, Republic of Korea.
| | - Y S Kim
- Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro43-gil, Songpa-gu, Seoul, 138-736, Republic of Korea.
| |
Collapse
|
32
|
Wi YM, Park YK, Moon C, Ryu SY, Lee H, Ki HK, Cheong HS, Son JS, Lee JS, Kwon KT, Kim JM, Ha YE, Kang CI, Ko KS, Chung DR, Peck KR, Song JH. The cefazolin inoculum effect in methicillin-susceptible Staphylococcus aureus blood isolates: their association with dysfunctional accessory gene regulator (agr). Diagn Microbiol Infect Dis 2015; 83:286-91. [PMID: 26277619 DOI: 10.1016/j.diagmicrobio.2015.07.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 07/15/2015] [Accepted: 07/16/2015] [Indexed: 10/23/2022]
Abstract
We evaluated the clinical significance of the cefazolin inoculum effect (CIE) in methicillin-susceptible Staphylococcus aureus (MSSA) isolates. In total, 146 isolates were recovered from patients with MSSA bacteremia at 9 hospitals in Korea. The CIE was observed in 16 MSSA isolates, and while type A was the only detected β-lactamase in MSSA isolates exhibiting the CIE, no strains expressing type B, C, or D β-lactamases exhibited this effect. The CIE was only observed in agr group III and I isolates and was significantly more common in isolates with agr dysfunction than in those with functional agr (P<0.001). Even among isolates producing type A β-lactamase, the CIE was also prevalent in isolates with dysfunctional agr than in isolates with functional agr (P=0.025). This study demonstrates an association between the CIE of MSSA isolates and agr dysfunction, in addition to those between the CIE and type A β-lactamase.
Collapse
Affiliation(s)
- Yu Mi Wi
- Division of Infectious Diseases, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Republic of Korea; Department of Medicine, The Graduate School of Yonsei University, Seoul, Republic of Korea
| | - Young Kyoung Park
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Chisook Moon
- Division of Infectious Diseases, Inje University Busan Paik Hospital, Busan, Republic of Korea
| | - Seong Yeol Ryu
- Division of Infectious Diseases, Keimyung University Dongsan Medical Center, Daegu, Republic of Korea
| | - Hyuck Lee
- Division of Infectious Diseases, Dong-A University, Busan, Republic of Korea
| | - Hyun Kyun Ki
- Division of Infectious Diseases, Konkuk University Hospital, Seoul, Republic of Korea
| | - Hae Suk Cheong
- Division of Infectious Diseases, Konkuk University Hospital, Seoul, Republic of Korea
| | - Jun Seong Son
- Division of Infectious Diseases, Kyung Hee University Hospital at Gangdong, Seoul, Republic of Korea
| | - Jin Seo Lee
- Division of Infectious Diseases, Kangdong Sacred Heart Hospital, Hallym University School of Medicine, Seoul, Republic of Korea
| | - Ki Tae Kwon
- Division of Infectious Diseases, Daegu Fatima Hospital, Daegu, Republic of Korea
| | - June Myong Kim
- Department of Medicine, The Graduate School of Yonsei University, Seoul, Republic of Korea
| | - Young Eun Ha
- Division of Infectious Diseases, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Cheol In Kang
- Division of Infectious Diseases, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Kwan Soo Ko
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.
| | - Doo Ryeon Chung
- Division of Infectious Diseases, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
| | - Kyong Ran Peck
- Division of Infectious Diseases, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Jae-Hoon Song
- Division of Infectious Diseases, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| |
Collapse
|
33
|
Chang SC, Liu TP, Chen CJ, Lin LC, Lu JJ. Detection of heterogeneous vancomycin-intermediate Staphylococcus aureus isolates using a combination of δ-hemolysis assay and Etest. Diagn Microbiol Infect Dis 2014; 81:246-50. [PMID: 25600843 DOI: 10.1016/j.diagmicrobio.2014.12.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 12/16/2014] [Accepted: 12/21/2014] [Indexed: 12/23/2022]
Abstract
This study evaluated the δ-hemolysis assay for detection of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) isolates. The assay was performed using Columbia or trypticase soy blood agar plates without vancomycin at 37°C with 5% CO2, and the test isolate was streaked perpendicularly 1mm away from S. aureus RN4220. One hundred thirty-eight methicillin-resistant S. aureus (MRSA) bloodstream isolates with vancomycin MICs of 0.75-2 μg/mL were screened for hVISA by the δ-hemolysis assay and Etest glycopeptide resistance detection (GRD) method. The δ-hemolysis assay could be read at 24h and was more sensitive and specific than the Etest GRD at 24h and 48 h for detection of hVISA. Because most hVISA isolates have a vancomycin MIC of 2 μg/mL, we recommend screening MRSA isolates first using Etest for those with an MIC of 2 μg/mL and then performing the δ-hemolysis assay on these isolates for hVISA.
Collapse
Affiliation(s)
- Shih-Cheng Chang
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan; Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Tsui-Ping Liu
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan
| | - Chih-Jung Chen
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Chang Gung Children's Hospital and Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan; College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Lee-Chung Lin
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan
| | - Jang-Jih Lu
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan; Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
| |
Collapse
|
34
|
Painter KL, Krishna A, Wigneshweraraj S, Edwards AM. What role does the quorum-sensing accessory gene regulator system play during Staphylococcus aureus bacteremia? Trends Microbiol 2014; 22:676-85. [PMID: 25300477 DOI: 10.1016/j.tim.2014.09.002] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 09/10/2014] [Accepted: 09/12/2014] [Indexed: 11/18/2022]
Abstract
Staphylococcus aureus is a major cause of bacteremia, which frequently results in serious secondary infections such as infective endocarditis, osteomyelitis, and septic arthritis. The ability of S. aureus to cause such a wide range of infections has been ascribed to its huge armoury of different virulence factors, many of which are under the control of the quorum-sensing accessory gene regulator (Agr) system. However, a significant fraction of S. aureus bacteremia cases are caused by agr-defective isolates, calling into question the role of Agr in invasive staphylococcal infections. This review draws on recent work to define the role of Agr during bacteremia and explain why the loss of this major virulence regulator is sometimes a price worth paying for S. aureus.
Collapse
Affiliation(s)
- Kimberley L Painter
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College, Armstrong Road, London SW7 2AZ, UK
| | - Aishwarya Krishna
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College, Armstrong Road, London SW7 2AZ, UK
| | - Sivaramesh Wigneshweraraj
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College, Armstrong Road, London SW7 2AZ, UK
| | - Andrew M Edwards
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College, Armstrong Road, London SW7 2AZ, UK.
| |
Collapse
|
35
|
Genetic and molecular predictors of high vancomycin MIC in Staphylococcus aureus bacteremia isolates. J Clin Microbiol 2014; 52:3384-93. [PMID: 25031442 DOI: 10.1128/jcm.01320-14] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
An elevated vancomycin MIC is associated with poor outcomes in Staphylococcus aureus bacteremia (SAB) and is reported in patients with methicillin-susceptible S. aureus (MSSA) bacteremia in the absence of vancomycin treatment. Here, using DNA microarray and phenotype analysis, we investigated the genetic predictors and accessory gene regulator (agr) function and their relationship with elevated vancomycin MIC using blood culture isolates from a multicenter binational cohort of patients with SAB. Specific clonal complexes were associated with elevated (clonal complex 8 [CC8] [P < 0.001]) or low (CC22 [P < 0.001], CC88 [P < 0.001], and CC188 [P = 0.002]) vancomycin MIC. agr dysfunction (P = 0.014) or agr genotype II (P = 0.043) were also associated with an elevated vancomycin MIC. Specific resistance and virulence genes were also linked to an elevated vancomycin MIC, including blaZ (P = 0.002), sea (P < 0.001), clfA (P < 0.001), splA (P = 0.001), and the arginine catabolic mobile element (ACME) locus (P = 0.02). These data suggest that inherent organism characteristics may explain the link between elevated vancomycin MICs and poor outcomes in patients with SAB, regardless of the antibiotic treatment received. A consideration of clonal specificity should be included in future research when attempting to ascertain treatment effects or clinical outcomes.
Collapse
|
36
|
James EH, Edwards AM, Wigneshweraraj S. Transcriptional downregulation of agr expression in Staphylococcus aureus during growth in human serum can be overcome by constitutively active mutant forms of the sensor kinase AgrC. FEMS Microbiol Lett 2013; 349:153-62. [PMID: 24164684 PMCID: PMC4274972 DOI: 10.1111/1574-6968.12309] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 10/11/2013] [Accepted: 10/17/2013] [Indexed: 01/05/2023] Open
Abstract
The temporal and cell density-dependent regulation of expression of virtually all the Staphylococcus aureus virulon is under the control of the agr (accessory gene regulatory) operon. The expression of the agr operon is subject to transcriptional regulation by the AgrA/C two-component response regulator/sensor kinase pair. During bacteraemia, a frequent syndrome caused by methicillin-resistant S. aureus (MRSA), the transcriptional downregulation of agr expression has been attributed to the sequestration of the quorum-signalling molecule auto-inducing peptide (AIP) by the human serum component apolipoprotein B as part of an innate immune response to infection. However, it is not known whether transcriptional downregulation of agr expression during growth in human serum is additionally subjected to regulation by transcription regulatory proteins that either directly or indirectly affect transcription from the agr operon promoters. Here, using chromosomal fluorescence reporters of agr expression in S. aureus, we show that the transcriptional downregulation of agr expression in human serum can be overcome using constitutive active mutant forms of AgrC. Therefore, it seems that the sequestration of the AIP is likely to be the only mechanism by which the host innate immune response limits agr expression at the transcriptional level to maintain the host-pathogen balance towards a noninvasive outcome.
Collapse
Affiliation(s)
- Ellen H James
- Faculty of Medicine, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | | | | |
Collapse
|