Microbiology lab: Content quiz 3

harmless in the intestine, but cause infection when in the habitat of the urinary tract, although little is known about what exactly turns virulence genes on to cause this. virulence strategy involves swarming and elongation.

most common cause of UTIs

a common urinary pathogen. similar to the other urinary pathogen of the same genus, but is a less efficient swarmer and is less virulent

a common urinary pathogen. often causes infection by biofilming on urinary catheters. more virulent and more efficient swarmer than the other urinary pathogen of the same genus

a toxin released by a bacterial cell into the environment. often deadly to cells

an enzyme that acts outside the bacterial cell. widely varied activity, can break connections between cells, kill cells, deactivate antibiotics, etc. not all deadly

an opportunistic pathogen that causes nosocomial infections. causes bacteremia, respiratory infections, and catheter-associated UTIs (by forming biofilms and climbing up catheter. this is the "pink scum" you find in showers

a food-borne pathogen. common airborne and dust-borne contaminant that enters food supply. spores contaminate food, then if they survive cooking and are held at room temperature, spores germinate and vegetative cells produce enterotoxins (toxins that effect intestines). especially common on rice.

an opportunistic pathogen that can be harmless on the skin, but causes infection if it gets into the bloodstream. causes infections of the skin, blood, and deep tissues (heart and bone)

a microbe that is normally part of the normal microbial flora of human skin. usually non-pathogenic, but may cause skin infections in severely immunocompromised patients

used to determine the ability of a microbe to produce gelatinases. a gelatinase-positive organism will secrete gelatinase and liquefy the medium while a gelatinase-negative organism will not secrete the enzyme and the medium will remain solid. gelatinases are a virulence factor that allows microbes to destroy our connective tissue

one way that neutrophils fight infections. when overwhelmed by microbes, neutrophils can rupture and form these, which are just neutrophil DNA and chemicals that trap bacterial cells. some bacterial pathogens avoid destruction by this mechanism by producing DNases

a test designed to detect DNases (type of exoenzyme), and therefore the ability of a microbe to break down neutrophil DNA (NETs). this is done using a nutrient medium containing methyl green, which binds to negatively-charged DNA. when DNA is broken down by DNases, a clear halo appears around the areas where the DNase-producing microbe has grown

this tests for the ability of pathogens to produce the exotoxin hemolysin, which is a virulence factor that allows pathogens to damage and cause lysis in RBCs.

partial hemolysis. RBC damaged, but mostly in tact. causes a green or brown discoloration in the medium.

complete lysis of red blood cells. a clear zone surrounds these colonies

a test used to determine a person's susceptibility to dental caries (cavities) by testing for microbes that are acid tolerant and produce acid via fermentation of glucose (Lactobacillus and Streptococcus species). uses a selective liquid medium that starts out blue/green with a low pH to inhibit growth of other microbes. color change to yellowish indicates susceptibility, but rate of change important. if within 24 hours, high susceptibility; it within 48 hrs, moderate; if within 72 hrs, slight.

complete removal of all viable cells (including endospores)

does not eliminate endospores but destroys them (bacteriocidal) or removes vegetative cells. an agent used on inanimate objects or surfaces but is often too toxic to use on human tissues

does not eliminate endospores but destroys or inhibits (bacteriostatic) vegetative cells. an agent that kills of inhibits growth of microbes but is safe to use on human tissue

A method for determining antibiotic susceptibility. Antibiotic-impregnated disks are placed on an agar plate whose surface has been inoculated with a test organism. The antibiotic diffuses away from the disk and inhibits growth of susceptible bacteria. The width of the zone of inhibition is proportional to the susceptibility of the organism.

targets cell wall synthesis

targets DNA unwinding

targets DNA unwinding

targets protein synthesis via targeting the 50s ribosomal subunit

targets protein synthesis via targeting the 30s ribosomal subunit

targets protein synthesis via targeting the 30s ribosomal subunit

targets flavoproteins

target folic acid synthesis

targets the outer membrane