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Staphylococcus Aureus Infection

Staphylococcus Aureus Infections

Staphylococcus aureus infection encompasses a broad spectrum of diseases affecting the skin, soft tissues, bones, joints, heart, and other organs. Each manifestation is associated with risk factors, clinical presentation, and diagnostic findings.


Presentation

Staphylococcus aureus, which has emerged as a major pathogen in the past decades [1], can infect the skin and soft tissues, bones, joints, lungs, endocardium, bloodstream, and other organs [2]. Normally, this bacterium colonizes about 30% of humans [3]. Epidemiology reports note that in addition to community-associated infections, this pathogen is also responsible for many health-care associated infections related to medical devices [2]. S. aureus is transmitted by contact with an infected person or contaminated objects, and inhalation of droplets. Risk factors for this infection are chronic lung diseases, diabetes mellitus, chronic skin diseases, influenza infection, malignancies, surgeries, immunosuppressant use, intravenous drug use, and HIV infection.

Clinical manifestations

S. aureus infection consists of diseases that range from benign to life-threatening [2] and their manifestations are described below.

Skin and soft tissue infections (SSTIs) include impetigo, cellulitis, and abscesses such as folliculitis, furuncles, and carbuncles. Very importantly, SSTIs can disseminate via the bloodstream and cause septicemia [4] and spread to muscles [5] and other organs [6].

Osteomyelitis and septic arthritis are two of the most serious S.aureus infections. Some of the features of osteomyelitis are fever, bone pain, and limping while septic arthritis features include fever and warm, erythematous, and painful joints with restricted motion [2].

Staphylococcal pneumonia is characterized by fever, respiratory distress, cyanosis, and gastrointestinal symptoms and primarily occurs in infants, children, and disabled individuals.

Symptoms of infective endocarditis (IE), which can affect heart valves and the endocardium, are fever, malaise, chills, and sweating. Moreover, patients may exhibit new onset of murmur or the worsening of a preexisting one, Osler nodes, Janeway lesions, Roths spots, subungual hemorrhages, and others.

One of the most ominous S.aureus infections is known as toxic shock syndrome (TSS). The CDC criteria for the diagnosis of TSS are 1) fever, 2) shock that is refractory to resuscitation, 3) diffuse macular rash, and 4) involvement of at least 3 organ systems [7]. Patients are likely to exhibit an altered mental status, vaginal hyperemia, skin manifestations, etc.

Furunculosis
  • Recurrent skin infections include boils (furunculosis), carbuncles, folliculitis and cellulitis. Cutaneous lesions can be more than 5 cm in size, and may be associated with necrosis.[patient.info]
Microscopic Hematuria
  • A 57-year-old woman developed exacerbation of atopic dermatitis, fever, and nephrotic syndrome with microscopic hematuria.[ncbi.nlm.nih.gov]

Workup

When evaluating a suspected S. aureus infection, the clinician should elicit the individual's personal history and risk factors, and perform a thorough physical exam and the appropriate studies.

Diagnostic tests

With regards to skin infections, inspection is usually sufficient to confirm the diagnosis although some cases will warrant aspiration and culture of the purulent material [8]. Also, ultrasonography may help in the diagnosis of soft tissue infections [9].

Osteomyelitis is typically associated with peripheral leukocytosis and increased levels of erythrocyte sedimentation rate (ESR) and serum C-reactive protein (CRP) [2]. Additionally, patients may have positive blood cultures, but if not, bone biopsy and culture should be performed [10]. Very importantly, imaging studies such as radiography, magnetic resonance imaging (MRI), and/or other modalities are obtained.

Septic arthritis is diagnosed based on elevated leukocytes in synovial fluid [11]. Moreover, the aspirated fluid is also sent for a culture and a Gram stain and radiography and/or other imaging tools are used in the workup.

To assess for S. aureus pneumonia, blood cultures are not reliable and therefore, a sample from the respiratory tract should be obtained. Additionally, chest radiography findings vary depending on whether the staphylococcal pneumonia is a primary or secondary infection. For example, primary infection demonstrates unilateral consolidation whereas secondary reveals bilateral involvement. Note that chest X-rays will reveal disease progression, which usually occurs rapidly.

Diseases such as IE and TSS are complicated and require an extensive workup. For example, patients diagnosed with IE should meet modified Duke criteria that consist of history and physical findings as well as blood culture and echocardiography results [12]. Finally, TSS requires a careful assessment of the history, physical exam, and the appropriate studies.

Gram-Positive Coccus
  • Abstract Staphylococcus aureus is a Gram-positive coccus that interacts with human hosts on a spectrum from quiet commensal to deadly pathogen.[ncbi.nlm.nih.gov]
Gram-Positive Bacteria
  • Gram-positive bacteria acquire resistance to beta-lactam antibiotics through the production of a protein called PBP2a, which is able to avoid the inhibitory effects of the antibiotics.[bcm.edu]

Treatment

  • Initial treatment with oxacillin and gentamicin was ineffective. Vancomycin was added to the regimen as the patient worsened, but after the 30(th) day of vancomycin treatment S. aureus was isolated from the blood.[ncbi.nlm.nih.gov]
  • No clinical improvement was observed after combined antibiotic treatment with rifampicin plus trimethoprim-sulfamethoxazole.[ncbi.nlm.nih.gov]
  • In this treatment network, hepatologists and a transplant surgeon cooperated to overcome severe infection and their efforts led to successful transplantation. On-line hemodiafiltration is an indispensable treatment option for acute liver failure.[ncbi.nlm.nih.gov]
  • Severe infections in RA patients treated with tocilizumab may present with mild symptoms despite severe and disseminated infection and, as these patients are severely immunodeficient-intensive diagnostic work-up and early treatment should be performed[ncbi.nlm.nih.gov]
  • Despite an early response to treatment with intravenous amikacin, reactivation of left orbital inflammation led to eventual loss of vision.[ncbi.nlm.nih.gov]

Prognosis

  • Deterioration of liver function caused LOHF, and LOHF has a poor prognosis, particularly when it is complicated by infection.[ncbi.nlm.nih.gov]
  • Staph Infection Prognosis When mild and promptly treated with antibiotics, the prognosis for recovery from a Staph infection is excellent. However, a MRSA infection can have an entirely different outlook.[onhealth.com]
  • Prognosis Necrotising pneumonia has a high mortality rate if not diagnosed early and treated energetically.[patient.info]

Etiology

  • […] of diseases in human communities. 2. the field of medicine concerned with the determination of the specific causes of localized outbreaks of infection, such as hepatitis, of toxic disorders, such as lead poisoning, or any other disease of recognized etiology[vdh.virginia.gov]
  • AR/MDROs Home Data FAQs Reporting Resources Organisms, Causative Agent, or Etiologic Agent Email Questions Transmission Once S. aureus is tested in the lab and known to be resistant to certain antibiotics, we call it methicillin-resistant Staphylococcus[dshs.state.tx.us]
  • Osteomyelitis: etiology, diagnosis, treatment and outcome in a public versus a private institution. Infection. 2001;29:333–6. 22. Bamberger DM. Diagnosis and treatment of osteomyelitis. Comp Ther. 2000;26:89–95. 23.[aafp.org]
  • Osteomyelitis: etiology, diagnosis, treatment and outcome in a public versus a private institution. Infection . 2001;29:333–6. 22. Bamberger DM. Diagnosis and treatment of osteomyelitis. Comp Ther . 2000;26:89–95. 23.[aafp.org]

Epidemiology

  • Pygmies), combined with close contact with animals (e.g. livestock and domestic animals, and wildlife), makes the epidemiology of S. aureus on the African continent unique and fascinating.[ncbi.nlm.nih.gov]
  • In this review, the epidemiology of S. aureus in both healthcare facilities and communities in Asia is addressed, with an emphasis on the prevalence, clonal structure and antibiotic resistant profiles of the MRSA strains.[ncbi.nlm.nih.gov]
  • Timely use of molecular epidemiological tools, however, demonstrated that their illnesses were caused by unrelated bacterial strains.[ncbi.nlm.nih.gov]
  • Reviews addressing S. aureus virulence and pathogenesis (Thammavongsa et al. 2015), as well as epidemiology and pathophysiology (Tong et al. 2015), have recently been published.[ncbi.nlm.nih.gov]
  • Abstract We report on the follow-up and epidemiological study triggered by the isolation of the first vancomycin-resistant Staphylococcus aureus (VRSA) detected in Europe.[ncbi.nlm.nih.gov]
Sex distribution
Age distribution

Pathophysiology

  • Hydrocephalus is thought to be associated with arachnoiditis caused by S aureus infection, which provides new insights into the pathophysiology of arachnoiditis.[ncbi.nlm.nih.gov]
  • Reviews addressing S. aureus virulence and pathogenesis (Thammavongsa et al. 2015), as well as epidemiology and pathophysiology (Tong et al. 2015), have recently been published.[ncbi.nlm.nih.gov]

Prevention

  • CONCLUSIONS: CSA-90 can promote osteogenesis and be used for prevention of Staphylococcus aureus infection in preclinical models.[ncbi.nlm.nih.gov]
  • This case highlights the need for rapid diagnosis and appropriate treatment of severe S aureus infection to prevent serious complications.[ncbi.nlm.nih.gov]
  • Editorial: Spreading the Benefits of Infections Prevention in the NICU In a related editorial, Pablo J.[sciencedaily.com]
  • Prevention: Hand washing is the single most important way to prevent the spread of staph infections.[conditions.health.qld.gov.au]
  • This rapid test could prevent the initiation of inappropriate therapy and adverse outcomes.[ncbi.nlm.nih.gov]

References

Article

  1. Marra F, Patrick DM, Chong M, et al. Population-based study of the increased incidence of skin and soft tissue infections and associated antimicrobial use. Antimicrob Agents Chemother. 2012; 56(12):6243-6249.
  2. Tong SY, Davis JS, Eichenberger E, et al. Staphylococcus aureus Infections: Epidemiology, Pathophysiology, Clinical Manifestations, and Management. Clin Microbiol Rev. 2015;28(3):603-61.
  3. Wertheim HF, Melles DC, Vos MC, et al. The role of nasal carriage in Staphylococcus aureus infections. Lancet Infect Dis. 2005;5(12):751–762.
  4. Spellberg B. Skin and soft-tissue infections: modern evolution of an ancient problem. Clin Infect Dis. 2010;51(8):904-6.
  5. Jaramillo D. Infection: musculoskeletal. Pediatr Radiol. 2011;41 (Suppl 1):S127-34.
  6. Lane JW, Tang J, Taggard D, Byun R. Successful use of daptomycin and linezolid, without surgical intervention, in the treatment of extensive epidural abscess and bacteremia due to methicillin-resistant Staphylococcus aureus (MRSA). Infect Dis Clin Pract. 2011;19(5):362-364.
  7. Centers for Disease Control and Prevention. Case definitions for infectious conditions under public health surveillance. MMWR Recommend Rep. 1997;46(RR-10):1–55.
  8. Patel Wylie F, Kaplan SL, Mason EO, Allen CH. Needle aspiration for the etiologic diagnosis of children with cellulitis in the era of community-acquired methicillin-resistant Staphylococcus aureus. Clin Pediatr (Phila). 2011;50(6):503-7.
  9. Sivitz AB, Lam SH, Ramirez-Schrempp D, et al. Effect of bedside ultrasound on management of pediatric soft-tissue infection. J Emerg Med. 2010;39(5):637-43.
  10. Mylona E, Samarkos M, Kakalou E, et al. Pyogenic vertebral osteomyelitis: a systematic review of clinical characteristics. Semin Arthritis Rheum. 2009;39(1):10–17.
  11. Margaretten ME, Kohlwes J, Moore D, Bent S. Does this adult patient have septic arthritis? JAMA. 2007;297(13):1478–1488.
  12. Fournier PE, Casalta JP, Habib G, et al. Modification of the diagnostic criteria proposed by the Duke Endocarditis Service to permit improved diagnosis of Q fever endocarditis. Am J Med. 1996;100(6):629–633.

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Last updated: 2019-07-11 20:08