Staphylococcus aureus – Panton-Valentine toxin – lukS-PV and lukF-PV genes: Culture; Molecular diagnosis (PCR)
Staphylococcus aureus, known as golden staphylococcus, is a bacterium of the genus Staphylococcus, of the family Staphylococcaceae that is widely distributed throughout the world, estimating that one in three people are colonized, although not infected, by this bacteria. This microorganism is considered part of the normal microbiota, but sometimes it can cause a wide range of diseases, ranging from cutaneous and mucosal infections, such as folliculitis, forunculosis or conjunctivitis, to fatal systemic diseases, such as cellulite, Deep abscesses. osteomyelitis, meningitis, sepsis, endocarditis or pneumonia. In addition, it can also affect the gastrointestinal tract, either by the physical presence of S. aureus or by the intake of staphylococcal enterotoxin secreted by the bacteria.
Staphylococcus aureus is a gram-positive anaerobic facultative bacterium, 0.5 to 1 μm in diameter, producing coagulase, catalase, immobile and non-sporulated. S. aureus has a circular chromosome of approximately 2800 kilograms of bases. S. aureus produces toxins that are divided into 4 types: cytotoxins (toxin-α, toxin-β, toxin-γ, toxin-δ and Panton-Valentine leucocidin (PVL)), enterotoxins (A, B, C1, C2 C3, D and E, associated with food poisoning), exfoliative toxins (Exfoliative toxin A -ETA- and Exfoliative toxin B -ETB-) and toxic shock toxins (TSST-1). There are some strains of S. aureus that produce a cytotoxin, called Panton-Valentine toxin, with more leukotoxic activity than all others. This cytotoxin is encoded by two simultaneous transcription genes, lukS-PV and lukF-PV. It is estimated that it is found in less than 5% of intra-hospital methicillin-resistant S. aureus (MRSA) strains and in virtually all community MRSA strains. This cytotoxin has been particularly linked to boils, skin abscesses, and serious infections of the necrotic skin.
S. aureus is a very resistant and long-lasting bacterium, remaining in the air or on objects, although the spread of this microorganism occurs mainly from person to person. Certain factors predispose the person to develop a disease, such as those individuals who routinely use needles (diabetics, allergies, hemodialysis patients or drug addicts), those with chronic skin infections (psoriasis, eczema or atopic dermatitis) and health-care peopple. In addition, food can also cause S. aureus infection, particularly pastry products, salads with potatoes and eggs, chicken, ham, dairy or creams.
This bacterium is part of the normal microbiota of people, where it is located in the skin and mucous membranes without causing infection. However, when this microorganism penetrates the tissues, for example, through a wound, it can cause a wide range of infections due to its production of toxins. Colonization by S. aureus occurs preferably in people with type 1 diabetes, intravenous drug users, patients with hemodialysis, surgical patients and people with AIDS. S. aureus infection can lead to a wide variety of infectious processes such as staphylococcal scalded skin syndrome, food poisoning, staphylococcal toxic shock syndrome, skin abscess, impetigo, folliculitis, furunculosis, face and neck cellulitis, hidradenitis suppurativa, mastitis, wound infection, bacteremia, endocarditis, pneumonia and empyema, osteomyelitis, septic arthritis, meningitis, peritonitis, pericarditis and pyomyositis, among others.
Tests performed in IVAMI:
- Detection by isolation in culture in selective media.
- Molecular detection (PCR) for lukS-PV
- Molecular detection (PCR) for lukF-PV
- Molecular diagnosis (PCR), to detect Staphylococcus aureus
- Staphylococcus aureus strain in culture or frozen.
- Total blood extracted with EDTA (2 to 5 mL)
- Exudate from abscess or infected tissue.
Storage and shipment of the sample:
- Refrigerated (preferred) for less than 2 days.
- Frozen: more than 2 days.
Schedule for results:
- Molecular diagnosis (PCR): 24 to 48 hours.
- Sample culture and molecular detection: 48 to 72 hours.
Cost of the test:
- Molecular detection of Panton-Valentine toxin from Staphylococcus aureus in strain from culture: Consult to firstname.lastname@example.org.
- Culture of sample and molecular detection (PCR) in the sample: Consult to email@example.com.