- Clinical science
Staphylococci are gram-positive, spherical-shaped bacteria that form clusters and are commonly found on the skin and mucous membranes. Clinically, the most important species include Staphylococcus aureus and Staphylococcus epidermidis, which are categorized according to their coagulase activity. S. aureus is coagulase positive and expresses several virulence factors which support evasion of the host immune response. S. epidermidis is coagulase negative and is usually less virulent, although it can evade the host immune system by forming and subsequently hiding in a biofilm. S. aureus is commonly responsible for many localized infections (e.g., , cervical ) and also severe organ infections in the setting of bacteremia (e.g., , ). As a toxin producer, S. aureus can cause food poisoning (see ) and, in severe cases, life-threatening diseases such as (SSSS) or (TSS). Methicillin-resistant S. aureus ( ), in particular, poses a major threat to both immunocompromised and multimorbid patients and is a considerable challenge to hospital hygiene. S. epidermidis is mostly responsible for foreign body infections caused by, for example, contaminated peripheral lines or prosthetic joints. The treatment of choice is anti-staphylococcal penicillins (e.g., oxacillin, flucloxacillin) or first and second generation cephalosporins.
Staphylococci are immotile, gram-positive bacteria that have a round shape and are found in clusters.
S. aureus colonizes approx. 37% of the general human population.
- Three patterns of carriage have been observed: 20% are permanent carriers, 60% are intermittent carriers, 20% are noncarriers
- MRSA carrier rates and invasive infections have increased during the last decades.
Epidemiological data refers to the US, unless otherwise specified.
- Penicillinase (a β-lactamase)
- Protein A
- Capsular polysaccharides
- Enzymes that destroy host tissues
- Anti-staphylococcal penicillins: oxacillin, flucloxacillin
- First and second generation cephalosporins
- In case of penicillin allergy: clindamycin
- vancomycin and linezolid : drugs of last resort such as
Coagulase-negative staphylococcus (particularly S. epidermidis)
Ear, nose, and throat
- Infections associated with catheters and shunts
- Treatment: antibiotic treatment and removing the foreign body (in most cases)
Staphylococcal toxic shock syndrome
- ∼ 50% of cases: caused by prolonged use of tampons over several days
- Postsurgical or after wound infections
- Pathophysiology: exotoxins (see )
- Clinical findings: if tampon related, symptoms usually appear within five days after menstruation.
- Laboratory tests
- Clinical findings
- Laboratory findings