Microbiology: Photos

USMLE - Micro AntiMicrobials

These antibiotics — Penicillin, Methicillin, Ampicillin, Piperacillin, Cephalosporins, Aztreonam, and Imipenem — prevent bacterial cell wall formation by inhibiting peptidoglycan cross-linking, leading to cell lysis and death.

USMLE - Micro Systems

The skin’s normal dominant flora is Staphylococcus epidermidis, a non-pathogenic bacterium that helps protect against harmful microbes by competing for space and nutrients.

USMLE - Micro Viruses

Reassortment occurs when viruses with segmented genomes exchange genetic segments, creating new combinations. This can lead to rapid evolution, high-frequency recombination, and potentially global pandemics. A common example is the influenza virus.

USMLE - Micro Parasites

The movement of molecules against their concentration gradient, from low to high concentration, using energy from ATP.

USMLE - Micro Mycology

Includes Histoplasma, Blastomyces, Coccidioides, and Paracoccidioides, which cause pneumonia and systemic dissemination

USMLE - Micro Bacteria

Identification begins with the catalase test: catalase-negative indicates Streptococcus, catalase-positive indicates Staphylococcus. Staph aureus is coagulase-positive, while S. epidermidis (novobiocin-sensitive) and S. saprophyticus (novobiocin-resistant) are coagulase-negative.