Inflammation and repair: spreading cellulitis: practice question

A Pathology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Pathology · Inflammation and repair: spreading cellulitis

Sample item

A leg develops a diffuse, rapidly spreading, warm red swelling without a localised pus collection. Which bacterial enzyme most readily explains the lack of localisation?

AHyaluronidase breaking down connective tissue ground substanceBUrease alkalinising the environmentCCatalase neutralising hydrogen peroxideDCoagulase forming a fibrin barrier around the focus

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Hyaluronidase breaking down connective tissue ground substance

Streptococcus pyogenes produces hyaluronidase, streptokinase and DNase, which dissolve ground substance and fibrin and let infection spread through tissue planes as cellulitis. Staphylococcal coagulase, in contrast, promotes localised abscesses.

Option by option

A. Hyaluronidase breaking down connective tissue ground substance (correct)
Correct. Hyaluronidase breaks down connective tissue and allows diffuse spread.
B. Urease alkalinising the environment
Urease is relevant to organisms such as Proteus and Helicobacter, not to cellulitis.
C. Catalase neutralising hydrogen peroxide
Catalase protects the organism from peroxide but does not explain tissue spread.
D. Coagulase forming a fibrin barrier around the focus
Coagulase walls off the infection and favours abscess formation.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Pathology question

What is the answer to this Pathology question?

The best answer is A, Hyaluronidase breaking down connective tissue ground substance. Streptococcus pyogenes produces hyaluronidase, streptokinase and DNase, which dissolve ground substance and fibrin and let infection spread through tissue planes as cellulitis.

Why is "Urease alkalinising the environment" not the answer?

Urease is relevant to organisms such as Proteus and Helicobacter, not to cellulitis.

Why is "Catalase neutralising hydrogen peroxide" not the answer?

Catalase protects the organism from peroxide but does not explain tissue spread.

Why is "Coagulase forming a fibrin barrier around the focus" not the answer?

Coagulase walls off the infection and favours abscess formation.

What concept does this question test?

It tests Inflammation and repair: spreading cellulitis in Pathology. Staphylococcal coagulase, in contrast, promotes localised abscesses.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Inflammation and repair: spreading cellulitis?

Learn each disease as a bundle: cause, key histology, markers, and the clinical hallmark. Then use the flashcards and the other Pathology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.