BIO220 Lecture Exam 6 (Ch 18, 19, 20)

Staphylococcus aureus

-causes skin infections: furuncles (boils), carbuncles, impetigo, toxic shock syndrome,

- has the most virulence factors of any pathogen,

-found on the skin and mucous membranes, can therefore withstand high salt conditions, and temperature and pH fluctuations, Catalyze positive, coagulate positive, beta-hemolytic, MRSA - difficult to treat, have to use vancomycin, some isolates are even VRSA

Streptococcus pyogenes (Group A)

-causes Strep. throat/pharyngitis, scarlet fever due to erythrogenic toxin, rheumatic fever, and other conditions, catalase negative, Beta-hemolytic, fastidious - grow on blood agar, treated with penicillin.

Streptococcus pneumoniae

-causes 60-70% of bacterial pneumonia, and causes otitis media & meningitis in young children

-capsule = major virulence factor

Streptococcus agalactiae (Group B)

pregnant women are tested for carriage of this organism due to the risk of infection to newborns (meningitis)

-fastidious – grow on blood agar, treated with penicillin

CAMP factor test

Differentiates Group B Strep (Strep. agalactiae) (+) from other Strep (-) strains that are also resistant to bacitracin & beta-hemolytic

Which Strep group is tested for in pregnancy before delivery? Why?

Group B

Streptococcus agalactiae may be present without symptoms and poses risk to meningitis infection of the newborn

Viridans Streptococci

- present in the oral cavity, can cause dental caries, can cause more serious infection in heart patients (take antibiotics prophylactically for invasive dental work).

Neisseria meningitidis (meningococcus)

causes epidemic meningitis (prevalent cause of meningitis), the "meningococcus," very fastidious - grow on chocolate agar, children and young adults are at highest risk, vaccine available, can be deadly if untreated, hallmark symptom is a stiff neck, treated with penicillin, close contacts of infected person treated prophylactically

Neisseria gonorrhoeae

causes STD that is asymptomatic 10% in males & 50% of the time in females, causes discharge in both & possible infertility due to scarring, females diagnosed via culture & further culture testing and males diagnosed by Gram stain of urethral pus.

Bacillus anthracis

causes anthrax, has cutaneous (skin), pulmonary (lung), and gastrointestinal forms, treated with Cipro antibiotic, complex vaccination only for military personnel. Cutaneous form causes black eschar lesion, spores are formed centrally in the Bacillus anthracis cells.

Bacillus anthracis - modes of entry

skin/cutaneous - open wound or cut

pulmonary - inhalation

gastrointestinal - ingestion of contaminated meat

Bacillus cereus

Aerobic spore-former

-attached to dust particles, everywhere, and

-can cause 24-hour diarrhea, No treatment, short-lived (particularly from reheated fried rice dishes)

Clostridium perfringens

anaerobic, spore-former, gram +

-can cause gas gangrene

-treatment - clean wounds, hyperbaric oxygen therapy

-Can also cause mild intestinal illness (food poisoning), Spores are formed terminally

Clostridium difficile (C. diff)

causes antibiotic-associated colitis, treatment - replace fluids and stop broad-spectrum antibiotics causing the problem (present in low numbers in the colon already and broad-spectrum antibiotics cause it to overgrow, resulting in infection), major cause of black-watery diarrhea in hospitals.

Clostridium botulinum

-causes botulism, anaerobic, spore-former, causes gastroenteritis, produces botulin toxin, which causes blocks acetylcholine at the neuromuscular junction in muscles so they are unable to contract (can be fatal if becomes systemic)

-can especially be found in inadequately preserved home canned foods

Clostridium botulinum - honey

-presence of spores in honey can cause infant botulism - reason why honey has warning that it is not to be given to children under 1 year of age because their immune systems can't handle a few spores until after 1 year of age.

Clostridium tetani

anaerobic, spore-former, found in the soil, causes tentanus/lockjaw, the "T" in the DTaP (or similar) vaccine - booster needed every 10 years, tetanospasmin toxin causes muscles to contract (can be fatal), treated with penicillin or tetracycline, antitoxin, & muscle relaxers

Listeria monocytogenes

causes Listeriosis, a disease associated with contaminated dairy products, poultry, meat, and sometimes produce, can cause miscarriage in pregnant women, prevented by pasteurization and proper cooking, virulence factor = they induce their own phagocytosis and multiply in phagocytes instead of being digested there.

Corynebacterium diphtheriae

causes diphtheria, low cases in last 115 years due to the "D" in the DTaP (or similar) vaccine, has two stages of disease - first localized in the throat and also characterized by visible "bull neck" swelling and grayish-white pseudo-membrane formation in the back of the throat, and then A-B toxin producing stage affects the organs.

Propionibacterium acnes

Certain strains, cause acne (and other “healthy” strained actually prevent it)

Mycobacterium tuberculosis

-causes tuberculosis (TB), symptoms include tubercles in lungs, malaise, fever, chills, productive cough (bloody sputum), weight loss,

-confirmed by acid-fast positive stain, positive Mantoux skin test, chest x-ray showing tubercles

Acid-fast staining

Mycobacterium species are acid-fast positive due to presence of mycolic acids in cell wall, other bacteria are acid-fast negative

Mycobacterium leprae

-causes leprosy (also called Hansen's Disease), detected by feather test (for reduced sensation) and by acid-fast bacilli from lesions. still occurs worldwide, but rarely

-about 100 cases per year diagnosed in the US and the warmer climate – treatment is combined and long-term, not very contagious, isolation is not necessary, the closest physical contact should be avoided

Pseudomonas aeruginosa

produces blue-green pigment and grape-like odor in culture and in wound infections.

Brucella

causes undulant fever, a.k.a. Bang disease, produces undulating fever pattern that can last a year, usually affects veterinarians & farmers

Which bacterial strains are particularly fastidious so they will only grow on chocolate agar?

Neisseria & Haemophilus

Francisella tularensis

causes "Rabbit fever"

Bordetella pertussis

-causes "Whooping Cough" (patients make characteristic "whoop" sound),

-the "P" in the DTaP (or similar) vaccine

Legionella pneumophila

-found in standing water, ex. ponds or stagnant air conditioning water (usually effects males over 50)

-causes Legionnaire's disease

Enterobacteriaceae family

Escherichia coli, Klebsiella pneumonia, Enterobacter, Citrobacter, Serratia marcescens

- cause diarrheal diseases and UTIs due to close proximity to the urinary tract.

E. coli EHEC

Enterohemorrhagic (EHEC) strain that causes hemorrhagic syndrome and kidney damage

E. coli

-causes 70% of traveler's diarrhea, 50-80% of UTI's (often treated with Cipro antibiotic),

-has pathogenic and hemorrhagic strains, ex. 0157:H7, that produces a toxin.

Serratia marcescens

can cause pneumonia, especially in compromised patients, produces bright red pigmented colonies in culture.

Proteus

Can cause UTI, wound infections, pneumonia

Salmonella typhi

primary/true pathogen, causes typhoid fever, source is fecally-contaminated food or water, causes invasive diarrhea that can lead to septicemia

Salmonella enteritidis

primary/true pathogen, source is animals including reptiles, or fomites, causes gastroenteritis.

True/Primary Pathogens

Salmonella & Shigella

Shigella

Primary/true pathogen, causes shigellosis dysentery

Yersinia pestis

-causes "black plague,"

-bubonic, septicemic, and pneumonic (contagious, fatal) forms; vector = fleas

Haemophilus influenzae

-causes acute bacterial meningitis in young children, prevented by the Hib vaccine

Haemophilus aegyptius

causes pinkeye

Haemophilus parainfluenza

Normal flora, can cause endocarditis