title: Sepsis induced by Staphylococcus aureus: participation of biomarkers in a murine model.
abstract: BACKGROUND
  This study aimed to evaluate the role of biomarkers in the pathophysiological process induced by a Staphylococcus aureus strain obtained in a hospital environment. For this, we intraperitoneally inoculated groups of male BALB/c mice with S. aureus, using a clinical isolate (CI) of S. aureus.
  
  
  METHODS
  Mice were divided into groups according to time of euthanasia (24, 48, 72, 96, 120, 144, and 168 hours of infection). After being euthanized, blood samples were collected for quantification of microorganisms and leukocytes, as well as measurement of biomarkers of tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), C-reactive protein (CRP), and Procalcitonin (PCT) by ELISA. Heart, kidneys, and lungs were removed for histopathological analysis, assessment of biomarkers of tissue expression by RT-PCR (polymerase chain reaction with reverse transcriptase), and quantification of microorganisms by real-time quantitative PCR (real-time PCR).
  
  
  RESULTS
  The animals infected at between 120 hours and 168 hours had the highest blood levels of S. aureus. We observed that infection promoted increases in the levels of circulating neutrophils and monocytes. However, there was a reduction of circulating neutrophils and monocytes after 96 hours of infection. The infected mice also had increased levels of blood lymphocytes. In this model of infection with S. aureus, IL-6, CRP, and PCT demonstrated greater fidelity as markers of infection, since serum levels were elevated and lowered along with the number of circulating neutrophils and monocytes after resolution of the infection. The lungs showed hyperemia, with enlargement of the alveolar septa. On the other hand, infection with S. aureus did not promote visible change in histological tissue in the heart and kidneys.
  
  
  CONCLUSIONS
  In this model of infection with S. aureus, IL-6, CRP, and PCT demonstrated greater fidelity as markers of infection, since serum levels were elevated and lowered along with the number of circulating neutrophils and monocytes after resolution of the infection. We believe our results may provide a better understanding of the pathophysiology, as well as aid in the search for a more reliable method of diagnosis.
authors: Multidisciplinary Institute of Health, Federal University of Bahia, Vitória da Conquista, Brazil.
authors: Thiago Henrique Caldeira
authors: TH
authors: de Oliveira
authors: Multidisciplinary Institute of Health, Federal University of Bahia, Vitória da Conquista, Brazil.
authors: Aline Teixeira
authors: AT
authors: Amorin
authors: Multidisciplinary Institute of Health, Federal University of Bahia, Vitória da Conquista, Brazil.
authors: Izadora Souza
authors: IS
authors: Rezende
authors: Multidisciplinary Institute of Health, Federal University of Bahia, Vitória da Conquista, Brazil.
authors: Maysa
authors: M
authors: Santos Barbosa
authors: Multidisciplinary Institute of Health, Federal University of Bahia, Vitória da Conquista, Brazil.
authors: Hellen Braga
authors: HB
authors: Martins
authors: Multidisciplinary Institute of Health, Federal University of Bahia, Vitória da Conquista, Brazil.
authors: Anne Karoline Pereira
authors: AK
authors: Brito
authors: Multidisciplinary Institute of Health, Federal University of Bahia, Vitória da Conquista, Brazil.
authors: Ewerton Ferraz
authors: EF
authors: Andrade
authors: Multidisciplinary Institute of Health, Federal University of Bahia, Vitória da Conquista, Brazil.
authors: Gleisy Kelly Neves
authors: GK
authors: Gonçalves
authors: Department of Microbiologia, Biomedical Science Institute, São Paulo University, São Paulo, Brazil.
authors: Guilherme Barreto
authors: GB
authors: Campos
authors: Multidisciplinary Institute of Health, Federal University of Bahia, Vitória da Conquista, Brazil.
authors: Robson Amaro Augusto
authors: RA
authors: Silva
authors: Department of Microbiologia, Biomedical Science Institute, São Paulo University, São Paulo, Brazil.
authors: Jorge
authors: J
authors: Timenetsky
authors: Multidisciplinary Institute of Health, Federal University of Bahia, Vitória da Conquista, Brazil.
authors: Lucas Miranda
authors: LM
authors: Marques
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000097:blood / Q000378:metabolism*; D002097:C-Reactive Protein / Q000737:chemistry; D002116:Calcitonin / Q000097:blood; D015740:Calcitonin Gene-Related Peptide; D004797:Enzyme-Linked Immunosorbent Assay; D020869:Gene Expression Profiling; D007249:Inflammation / Q000382:microbiology; D015850:Interleukin-6 / Q000097:blood; D007958:Leukocyte Count; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011498:Protein Precursors / Q000097:blood; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018805:Sepsis / Q000382:microbiology* / Q000503:physiopathology*; D013203:Staphylococcal Infections / Q000503:physiopathology*; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
chemical_list: D015415:Biomarkers; C000606590:Calca protein, mouse; D015850:Interleukin-6; D011498:Protein Precursors; D014409:Tumor Necrosis Factor-alpha; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide
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