CELLULITIS

Aspect

Details

Definition

●Cellulitis is a bacterial infection affecting the deeper layers of the skin and the subcutaneous tissues.

●It is commonly caused by Streptococcus or Staphylococcus bacteria.

Common Areas Affected

●Typically occurs on the lower legs.

●Can develop on any part of the body, particularly where the skin has been broken.

Causes

Bacteria entering the skin through:

●Cuts, scrapes, or surgical wounds

●Insect bites, animal bites, or burns

●Pre-existing skin conditions like eczema or athlete's foot

●Weakened immune systems due to conditions such as diabetes or vascular disease

Risk Factors

●Chronic skin conditions (eczema, psoriasis)

●Immunocompromised individuals

●Recent surgery, diabetes

●Obesity, peripheral artery disease

●IV drug use, new tattoos or piercings

Symptoms

●Red, swollen, warm, and tender skin

●Rapid expansion of the affected area

●Fever, chills, fatigue, and swollen lymph nodes

●Fluid-filled blisters and “orange-peel” texture of the skin in severe cases

●Potential systemic signs in severe infections (confusion, rapid heart rate, low blood pressure)

Treatment

●Oral or intravenous antibiotics (penicillin, cephalexin, etc.)

●Surgical drainage for abscesses

Characteristic

Streptococcus

Staphylococcus

Shape

Chains or pairs of spherical bacteria

Clusters (grape-like) of spherical bacteria

Gram Staining

Gram-positive

Gram-positive

Common Species

S. pyogenes (Group A), S. pneumoniae

S. aureus, S. epidermidis

Pathogenicity

Causes infections like strep throat, scarlet fever, rheumatic fever, pneumonia, and necrotizing fasciitis

Causes infections like skin infections, abscesses, pneumonia, endocarditis, toxic shock syndrome

Antibiotic Resistance

Penicillin-sensitive

Methicillin-resistant S. aureus (MRSA) is common

Habitat

Commonly found in the throat, skin, and respiratory tract

Commonly found on the skin and mucous membranes

PRACTICE QUESTION

 Q:Consider the following statements about Streptococcus and Staphylococcus Bacteria:

1.Both of them are gram negative bacteria.

2.Streptococcus bacteria are found on the skin and Staphylococcus Bacteria are found in the throat.

Which of the above statements is/are incorrect?

a) 1 only

b) 2 only

c) Both 1 and 2

d) Neither 1 nor 2 

Answer: c 

Explanation:

Both the statements are incorrect:  Streptococcus and Staphylococcus are both Gram-positive bacteria, meaning they retain the violet dye in the Gram staining process. However, their habitats differ slightly. Streptococcus is commonly found in areas such as the throat, skin, and respiratory tract, where it can cause various infections like strep throat, pneumonia, and scarlet fever. In contrast, Staphylococcus primarily resides on the skin and mucous membranes. It is often associated with skin infections, abscesses, and more serious conditions like toxic shock syndrome when it enters the bloodstream or deeper tissues.