Gram - Bugs Flashcards
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
- -neisseria meningitidis»meningitis
- -neisseria gonorrheae
moraxella catarrhalis (resides in respiratory tract, causes tracheobronchitis and pneumonia)
What is the most prevalent human bacterial STI?
-gonorrhea
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
- transmission?
- 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
OVERT DISEASE
-fulminant meningeal sepsis: fever, severe HA, vomiting, neck/back pain, stiffness, petechial rash, altered mental status, shock, organ failure.
- meningitis
- 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
- morphology?
- common inhabitant of?
- frequent contaminant of?
- most common cause of?
- complications
- 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
- odor?
- color?
- treatment
- grape-like odor
- greenish-blue pigment
- treat w/ cephalosporins, aminoglycosides, carbenicillin, polymixin, quinolones, and monobactams.
- Harleys go to is quinolones
Brucella and Brucellosis
- morphology
- what are the 2 species
- sx
- treatmen?
-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
- morphology
- causes what?
- transmitted how?
- sx
- tx
- 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
- morphology
- causes what disease?
- reservoir
- transmission
- 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?
- treatment?
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
- transmission?
- how did this bug get its name?
- sx
- tx
- 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
- UTI
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?
- aka
- morphology
- how do you get this?
- Plague
- 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?
- treatment?
- zoonotic genus; normal flora in animals.
- animal bites/scratches cause local abscess that can spread to joints, bones, and lymph nodes
-PCN and tetracycline
Haemophilus
- morphology
- 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
What are the strains of Haemophilus and what illness do they cause?
Treatment of Haemopholus sp?
H. flu= bacterial meningitis, epiglottitis, otitis media, sinusitis, pneumonia, bronchitis
H.aegyptius= conjunctivitis
H. ducreyi = chancroid STD
H.parainfluenzae= normal oral and nasopharyngeal flora, infective endocarditis
Tx: amoxicillin, azothrymycin, cephalosporins, FQ, and clarithromycin
Characteristics of anaerobic infections?
- most pathogenic anaerobes are usually commnesal
- have predisposing conditions such as..breech in mucocutaneous barrier, compromised vascular supply
- complex flora; multiple species,
- synergisic mixture of aerobes and anaerobes
(e. coli –> consume O2, allow growth for anaerobes
Clues to anaerobic infections?
- infection in continuity to mucosal surfaces
- infection w/ tissue necrosis and abscess formation
- putrid odor
- gas in tissues
- polymicrobial flora
- failure to grow in lab
Bacteroides fragilis
-when does this infection most commonly occur?
-what benefits come from having a capsule in this bug?
-
- major disease causing strict anaerobic after abdominal surgery*
- capsule: anti-phagocytic and abscess formation
Campylobacter jejuni
- leading cause of what kind of illness?
- transmission?
- treatment?
- leading cause of bacterial diarrheal illness
- transmission is oral/fecal route, ingestion of contaminated food and water, uncooked meat.
- treat w/ azithromycin, increasing resistance to FQ.
Lymes Disease
-what bug causes this?
-sx?
-
-borrellia burgdorgeri
- early sx: fever, HA, fatigue
- Late sx: rash (may or may not be bulls eye), joints, heart, and CNS involvement.
Dx and Tx of Lymes
- bulls eye rash
- Elisa: measures the levels of abys against the lyme bacteria
- western blot: identifies abys directed against a panel of proteins found in the lyme bactera
Tx:
-doxycycline or amoxicillin for 2-4weeks
Chlamydia trachomatis
- signs and symptoms in male and female
- treatment
- femaile patients may not have sx, males will have urethral drip and painful urination.
- treat w/ azithromycin, doxycycline or ofloxocin
Lymphogranuloma venereum (LGV)
- what is this?
- sx
- tx
-uncommon STI caused by three serovars of chlamydia trachomatis
- sx: swollen inguinal nodes, drainage through skin from buboes or abscesses in inguinal nodes
- -painful bowel movements
- -small painless sore on genitals
- -swelling of the labia
- -blood or pus from the rectum
- -left untreated may develop fistulas
- Tx: doxycyline, erythromycin, azithromycin)
- -I&D of buboes
Psittacosis
- what is this?
- symptoms
- diagnosis
- tx
“parrot fever”…zoonotic disease caused by chlamydia pssitaci contracted from parrots, pigeons, ducks, chickens, and gulls.
- sx: high fever, arthralgias, diarrhea, conjunctivitis, epistaxis, splenomegaly, HA, may mimic meningitis, cough
- dx: exposure hx!, microbiological cultures from respiratory secretions or serology from blood cultures
- tx: doxycycline and chloramphenicol
What are the two types of relapsing fever? What bacteria are they caused from?
- Tick borne (TBRF) & Louse borne (LBRF)
- caused from Borellia spirochetes
Where does TBRF and LBRF occur?
sx?
dx?
- TBRF=wester US, linked to sleeping in rustic, rodent infested cabins in mountainous areas.
- LBRF: transmitted by the human body louse and is generallly restricted to refugee settings in the third world.
sx: flu-like, sudden fever, chills, HA, arthralgias, nausea, may develop rash. - dx: on blood smear, spirochetes
Treatment of Relapsing fever?
doxycycline, may cause Jarish-Herxheimer rxn.
^^^massive die of of spirochetes, rash chills, not feeling well. not an allergy, just killing off the bug you intended to leading to mass release of endotoxin
Salmonella sp.
- flagellinated?
- sx
- most common cause of what illness?
-motile, flagellated gram neg.
- gastroenteritis (diarrhea, abd cramp, fever) to enteric fevers (typhoid fever)
- may be asymptomatic and be a carrier (typhoid marys)
-most common from is food poisoning
Selmonella typhi
- sx
- dx
- tx
- N/V/D, septicemia, fever, anorexia, HA, myalgias
- dx: stool &/or blood cultures, serology for abys
- Tx: replace fluids by oral or IV, pain control, treat nausea, abx=cipro.
Shigella
- sx
- who does this usually occur in?
- dx
- tx
sx: bloody diarrhea, abdominal pain/cramps, fever
- seen in kids 2-4
- dx: stool studies
- tx: replace lost fluids, usually self limiting within a weeks, cipro or cefixime should be used if abx indicated.
Vibro sp.
- what are the two distinct groups?
- how do you get ill from this?
- tx of non-cholera
- 2 types: cholera infections, non-cholera infections
- non-cholera: contaminated food or eating raw shellfish
- tx non-cholera: gasteroenteritis is usually self-limited with fluid replacement, no abx needed.
- *non-cholera wound infection or septicemia will need doxycyline or quinolone, debridement of infected wound.
Vibrio cholerae
- sx
- tx
-watery diarrhea, occasional vomiting, cramps, dehydration
death d/t dehydration can occur within a few hours to days if untreated.
