Clostridium perfringens causes gas gangrene, a serious infection of the muscle tissues that can lead to amputation. Clostridium are Gram-positive endospore-formers and obligate anaerobes that are killed when exposed to oxygen. Which of the following virulence factors would be most helpful to this organism in establishing an infection? Hints

Hint 1.

In order to establish a successful infection, a pathogen must arrive at a susceptible site, adhere, invade, acquire nutrients, and grow.

Clostridium perfringens causes gas gangrene, a serious infection of the muscle tissues that can lead to amputation. Clostridium are Gram-positive endospore-formers and obligate anaerobes that are killed when exposed to oxygen. Which of the following virulence factors would be most helpful to this organism in establishing an infection?

A endotoxin
B nuclease, an enzyme that breaks down nucleic acids
C collagenase, an enzyme that destroys collagen, which is a major protein of connective tissues
D a neurotoxin
Which phenotypic assay could be used to determine whether a new Streptococcus spp. is of the pyogenes or viridans group?

hemolytic type after growth on a blood agar plate
product(s) formed during lactose fermentation
catalase assay with H2O2
occurrence of cells being in clusters or as individual cells under a microscope