USMLE STEP 1 MICROBIOLOGY Questions and Answers with Complete Solutions 2024

USMLE STEP 1 MICROBIOLOGY Questions and Answers with Complete Solutions 2024 Gram-positive organisms - ANS____ have a thick peptidoglycan layer and teichoic acid in their cell walls Gram-negative organisms - ANS____ have a thin peptidoglycan layer and a complex outer membrane containing lipopolysaccharide (LPS). Lipoteichoic acid - ANS____ is a teichoic acid attached to a lipid abundant on Gram-positive bacteria cell wall. Peptostreptococci - ANSClassification: -- Anaerobic gram-positive cocci Characteristic: -- A normal flora of the mouth and colon. -- This organism forms abscesses in patients with alcoholism and seizure disorder Fusobacterium species - ANSClassification: -- Anaerobic gram-negative rods microorganism Characteristic: -- It forms abscesses in patients with alcoholism and seizure disorder. They are part of the human normal flora of the mouth, colon, and female genital tract. Staph. epidermidis - ANSClassification: -- Gram-Positive Cocci, Novobiocin sensitive. -- Catalase positive, Coagulase-negative Characteristic: -- This organism infects prosthetic devices and intravenous catheters by producing adherent biofilms. A compound of normal skin and nose flora. Staph. saprophyticus - ANSClassification: -- Gram-Positive Cocci, Novobiocin resistant -- Catalase positive, Coagulase-negative Characteristic: -- The Second most common cause of uncomplicated UTI in young women. Strep. pneumoniae - ANSClassification: -- A lancet-shaped encapsulated gram-positive dipl