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Flashcards in Gram - Bugs Deck (48)
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what is one thing all gram - bugs have in common??

-all have a lipopolysaccharid outer membrane of cell wall-endotoxin


What are the medically relevant gram - cocci?

--neisseria meningitidis>>meningitis
--neisseria gonorrheae

moraxella catarrhalis (resides in respiratory tract, causes tracheobronchitis and pneumonia)


What is the most prevalent human bacterial STI?



Where is a gonorrheal infection found in women and men?

-women: cervix
-men: urethra, may extend to prostate and epididymis causing sterility


Gonorrhea, does this spread beyond the urethra and cervix? if so, where?

-yes, may become systemic disease.
--arthritis, endocarditis, meningitis

-gonorrhea neonatorum, eye infection during passage through birth canal, may lead to blindness


Neisseria meningitidis
-causes what?
-natural reservoir

-meningitis, septicemia

-natural reservoir is the human nasopharyngeal mucosa

-transferred via direct contact or droplets


Neisseria meningitidis
-subclinical/minimal disease sx

-fulminant meningeal sepsis sx

-meningitis sx

-subclinical: short febrile flu-like sx, cleared spontaneously

-fulminant meningeal sepsis: fever**, severe HA**, vomiting**, neck/back pain, stiffness*, petechial rash*, altered mental status, shock, organ failure.

-fever, HA, vomiting, neck/back pain, skin rash, AMS


Fulminant meningeal sepsis and meningitis may progress to what?

-shock; endotoxin causes capillary leakage, poor vascular tone, intravascular microthrombi, myocardial dysfunction

-DIC; endothelial damage>>> hemorrahges, microthrombi


Meningitis rash, where is it often found on the body?

-pin point rash often on the trunk but sometimes on the hands.


Diagnosis of Fulminant meningeal sepsis and meningitis?

-FMS lesions appear 6-12 hours
-meningitis lesions appear 12-18hrs after onset, no lesions in 20% or pts

Bacteriologic dx:
FMS: gram stain of skin lesion biopsy specimen
Meningitis: only CSF positive


How do you treat FMS and meningitis?

-always start ABX IMMEDIATELY!! even before other diagnostic procedures.

-use cefotaxime or ceftriaxone plus vanco
-patients in contac... prophylactic abc Rocephin (ceftriaxone)


Moraxella Catarrhalis
-gram +/-?
-cause infections of?
-resistant to which meds?
-treat w/?

-gram -

-cause infection of upper and lower respiratory, middle ear, eye, CNS, joints

-resistant to PCN, SMX/TMP, tetracyclines

-treat w/ FQ, most 2nd, 3rd cephalosporins, macrolides, augmentin


Pseudomonas aeruginosa
-common inhabitant of?
-frequent contaminant of?
-most common cause of?

-gram - rod w/ single polar flagellum

-common inhabitant of soil and water

-contaminant of ventilators, IV solutions, anesthesia equipment

-most common cause of nosocomial infections

-complications include pneumonia, UTI, abcesses, otitis, corneal disease, endocarditis, meningitis, bronchopneumonia


Pseudomonas aeruginosa

-grape-like odor

-greenish-blue pigment

-treat w/ cephalosporins, aminoglycosides, carbenicillin, polymixin, quinolones, and monobactams.
**Harleys go to is quinolones*


Brucella and Brucellosis
-what are the 2 species

-gram - coccobacilli

-Brucella abortus (cattle)
Brucella suis (pigs)

-sx: malta fever, undulant fever*, bang disease(zoonosis transmitted to humans from infected animals
**fluctuating patter of fever, weeks to a year.

-tx: tetracycline and rifampin or streptomycin


How do you get Brucella species?

-consumption of unpasteurized milk and soft cheeses made from milk of infected animals.


Francisella tularensis
-causes what?
-transmitted how?

- facultative intracellular coccobacillus

-causese tularemia (zoonotic disease of mammals endemic to norther hemisphere, particularily rabbits)

-transmitted by contact with infected animals, water and dust or bites by vectors.

-Sx: HA, backkache, fever, chills, malaise, weakness

-tx: gentamycin or tetracycline


Bordetella pertussis
-causes what disease?

-encapsulated coccobacillus

-causes pertussis or whooping cough "100 day cough"

-reservoir is healthy carreiers

-transmitted by direct contact or inhalation of aerosols


Bordetella Pertussis
-virulence factors
-vaccine for this?

Virulence: bind to ciliated respiratory epithelial cells, toxins destroy and dislodge ciliated cells. Loss of ciliary mechanism leads to buildup of mucus and blockage of the airways.

-Tdap vaccine

-treat with macrolides....AZITHROMYCIN!


Legionella pneumophilia and Legionellosis
-how did this bug get its name?

-distributed in water, organisms inhaled in aerosolized mist

-pneumonia afflicted 200 American Legion members

-sx: fever, cough, diarrhea, abdomin pain

-tx: azithromycin


What are the pathogenic strains of e.coli? What

-enterotoxigenic E.Coli -causes severe diarrhea d/t heat-labile toxin and heat-stable toxin- stimulate secretion and fluid loss

-enteroinvasive e.coli: causes inflammatory disease of large intestine

-enteropathogenic e. coli: linked to wasting from infantile diarrhea

-enterohemorrhagic e.coli: O157:H7 strain, causes hemorrhagic syndrome and kidney damage


What is a coliform count used for?

-indicator of fecal contamination in water


e.coli is a major causes of what?

-travelers diarrhea


e.coli tx

-SMX/TMP, nitrofurantoin, FQs


Other than e.coli what are some other coliforms? Where are they found in the body? What type of infections do they cause?

-klebsiella pneumoniae-normal inhabitant of respiratory tract, has large capsule, cause of nosocomial pneumonia, meningitis, bacteremia, wound infections and UTIs

-enterobacter: UTI, surgical wounds

-serratia marcescens: produces red pigment, causes pneumonia, burn and wound infections, septicemia, and meningitis

-citrobacter: opportistic UTI and bacteremia


Yersenia Pestis?
-how do you get this?


-gram - rod, unusual bipolar staining and capsules

-contact with wild animals or infected humans *found in rodents, flea vectors


Pathology of Bubonic plague?
-may progress into what?

bacillus multiplies in flea bite, enters lymph, causes necrosis and swelling called a bubo in groin or axilla.

-septicemic: progression to massive bacterial growth; intravascular coagulation, subcutaneous hemorrhage and purpura-black plague.

-pneumonic: infection localized to lungs, highly contagious; fatal without treatment.


Tx of plague

streptomycin, tetracycline, or chloramphenicol


Pasteruella multocida
-what is this?
-how does it present?

-zoonotic genus; normal flora in animals.
-animal bites/scratches cause local abscess that can spread to joints, bones, and lymph nodes

-PCN and tetracycline


-what type of agar do you need to groww?
-colonize where in the body?

-gram - pleomorphic rods

-chocolate agar

-colonize of the upper respiratory tract or vagina