MICROBIOLOGY MOCK BOARD EXAMUST MBR 2026 QUESTIONS AND 2026 18pages

1. Autoclaving isthe best method of sterilization because: ❏ It is bacteriostatic → bactericidal ❏ The pressure makes the organism more sensitive to heat ❏ It kills both the spores and vegetative cells ❏ The high temperature oxidizes bacteria *Uses moist heatsignificantly affects coagulation of proteins (Ex. Pressure Cooker) 2. Alpha hemolytic streptococci are the most abundant: ❏ Wound contaminating organisms → combination of aerobic and anaerobic ❏ Skin contaminants → Staphylococcus epidermidis, Enterococcus, Viridans strep ❏ Normal throat bacteria → Streptococcus viridans ❏ Normal stool organisms → enterococci, enterobacter, Klebsiella 3. Based on their oxygen requirement, Clostridium is classified as: ❏ Obligate aerobe - Pseudomonas ❏ Microaerophile → Campylobacter ❏ Facultative anaerobe → most pathogenic organisms; Enterobacteriaceae ❏ Anaerobe → GRAM (+), SPORE FORMING 4. The presence of pili increases bacterial virulence by: ❏ Increasing attachment to host cells → sex pili involved in exchange of genetic material ❏ Preventing phagocytosis → capsule ❏ Blocking surface antibodies→ biofilm ❏ Producing bacterial toxins→ endotoxin and exotoxin present in gram (+) and (-) organisms 5. Toxic shock syndrome in menstruating women is caused by? ❏ Staphylococcus aureus → TSS; fever, rash, desquamation ❏ Staphylococcus epidermidis ❏ Streptococcus pyogenes ❏ Streptococcus agalactiae 6. A nonhemolytic, catalase positive, coagulase negative, Gram-positive cocci commonly associated with urinary tract infection is most likely ❏ Staphylococcus epidermidis → novobiocin sensitive ❏ Staphylococcus saprophyticus → Novobiocin resistant ❏ Streptococcus pyogenes → catalase negative; Bacitracin sensitive ❏ Streptococcus agalactiae → catalase negative