Studied by 40 people
Which spore forming gram positive bacilli causes anthrax?
Bacillus anthracis
List the three different types of bacillus anthracis infection and the portal on entry.
Cutaneous- skin, most common, least pathogenic
pulmonary-inhalation
GI-ingested
Describe the clinical findings with cutaneous anthrax
Starts as a papule → necrotic → ruptures → painless black eschar
What is another name for pulmonary anthrax?
Wool-sorter’s disease
What happens when the exotoxins in pulmonary anthrax are released?
Produces toxemia, capillary thrombosis, cardiovascular shock
What symptoms might a patient with pulmonary anthrax experience?
hemoptysis, severe substernal chest pain, shock, death
What radiographic findings would you expect in pts with bacillus anthrax?
Hemorrhagic mediastinitis w/ bloody pleural effusions, usually pulm infiltrates are not present, widened mediastinum w/ LAD
What is the first line antimicrobial used to treat anthrax? What are monoclonal antibodies also given? Why?
Ciprofloxacin (cipro); Raxibacumab- bind the toxins and prevent its entry to cells
Which population of individuals can receive an anthrax vaccine?
High risk occupations and military personnel
What type of self-limiting illness would a patient have if infected with Bacillus cereus?
GI upset/food poisoning x 24 hrs
Which foods are commonly involved in Bacillus cereus infxns?
Rice, potatoes, meat dishes; survive cooking and reheating
List the Clostridium species reviewed in class.
Perfringens, difficile, tetani, botulinum
Which is the most frequent species of Clostridium involved in wound infections?
Perfringens
Which is the most common species of Clostridium involved with food poisoning?
Perfringens -Type A
What potentially lethal infection of the muscle tissue is caused by Clostridium perfringens?
Gas gangrene/mycosis
What signs and symptoms would be expected w/ gas gangrene/mycosis?
Pain, edema, bloody exudate, fever, tachy, black necrotic tissue w/ gas bubbles
What is Fournier’s gangrene?
Acute necrotic infxn of scrotum, penis, or perineum (seen in C. perfringens)
Which Clostridium species is responsible for pseudomembranous colitis?
C. difficile
What does CDAD stand for?
Clostridium difficile- associated disease
What symptoms are associated with CDAD?
Range: asymptomatic, mild diarrhea, abdominal cramps, fever, fulminant colitis -> shock/death
What risk factors are associated with CDAD?
Hospitalization, exposure to abx, host susceptibility, GI surgery, tube feedings
What is the recommended therapy for mild CDAD? Severe?
Mild: stop abx, start vancomycin or metronidazole
Severe: combo of the drugs
Which Clostridium species is responsible for tetanus?
Clostridium tetani
What’s another name for tetanus?
lockjaw
How do the Clostridium tetani spores typically enter the body?
Accidental puncture wounds, burns, frostbite
What does the neurotoxin tetanospasmin cause?
Uncontrolled muscle contractions
Define opisthotonos.
Spasm of muscles causing backward arching of the head, neck, and spine
Which Clostridium species is associated with improper home canned food and raw honey?
Clostridium botulinum
How soon do botulism symptoms begin after ingestion?
8-16 hrs after ingestion
What symptoms are associated with a botulism infection?
Acute abd pain, diarrhea, nausea
What other ways can clostridium botulism microorganism enter the body?
Wounds → neurologic symptoms
Which non-spore forming gram positive bacilli can contaminate foods and continue to grow during refrigeration?
Listeria monocytogenes
Which food products should pregnant women avoid to prevent a Listeria infection?
Deli meats, soft cheeses, smoked fish products
What serious complications can occur if a pregnant woman becomes infected with Listeria?
Fetal death
Describe the morphology of Corynebacterium diphtheriae.
G+ irregular bacilli, straight/somewhat curved rod that tarps at the end
Describe the symptoms associated with a local diptheriae infection.
Upper resp tract inflammation + sore throat, grayish pseudomembrane, enlarged lymph nodes, severe swelling of the neck (Bull’s neck)
Is there a vaccination for Corynebacterium diphtheriae? What is the abbreviation for the vaccine given during childhood? Adolescents and adults?
Yes; DTaP -child; Tdap -adults (protect against C. dipth, C. tetani, bordetella pertussis)
What percentage of individuals infected with Mycobacterium tuberculosis develop clinical disease?
5-10%
What is the best type of diagnostic staining to identify TB?
Acid-fast staining
TB primarily affects the lungs. List the extrapulmonary sites discussed and the potential complications of each.
Renal: necrosis, scarring of renal medulla, pelvis, ureter, and/or bladder
Genital: damage to reproductive organs
Bones/joints: spine (most common), hip, knee, wrist, elbow
Neurological: intellectual disability, blindness, deafness
Differentiate primary from secondary TB.
Primary: asymptomatic-mild, vague sx, can cause caseous lesions
Secondary: can reactivate, violent cough, green/bloody sputum, fever, anorexia, wt loss, fatigue, night sweats, chest pain
What are the different methods for TB diagnosis?
TB skin testing (TST/Mantoux), interferon, acid-fast sputum stain, lab culture, chest xrays
Describe when a tuberculin skin test is considered positive and include the individuals associated with each of the three categories.
Cat 1: =/+ 5mm induration; who have contact w/ actively infect TB pts, HIV+, h/x TB, organ transplant recipients, immunosupressed
Cat 2: =/+ 10mm induration; HIV- IV drug users, risk for latent -> tb, children w/ members of high risk adult populations, mycobacteriology lab personnel
Cat 3: =/+ 15 mm induration, no risk factors
What can cause a false TB positive reaction?
Previous + rxns, hx of BCG vaccine
What does a positive TB skin test mean?
Recent contact or new infxn, reactivation of a prior infxn, false + due to BCG vaccine, or infection by a microbe that cross reacts w/ TB bacillus
Can you have an infection and get a negative TB skin test? In what situations will you see this?
Yes; Too early in the infection for sensitization, immunocompromised who is unable to react to antigen
What are the 4 medications used to treat active TB?
Isoniazid (INH)*, Rifampin (RIF)*, Pyrazinamide (PZA), Ethambutol (EMB)
* also in continuation phase
Which vitamin supplementation should always be given with INH for TB?
Pyridoxine (Vit B6)
What does Miliary TB represent?
Hematogenous spread of uncontrolled TB infxn
What will the CXR findings w/ miliary TB include?
Millet seed-sized tuberculi, random widespread tiny nodules, no consolidation, pleural fluid, or mediastinal/hilar enlargement
Which bacteria causes leprosy?
Mycobacterium leprae
Differentiate the tuberculoid and lepromatous forms of leprosy.
Tuberculoid: superficial infection w/o skin disfigurement which damages nerves and causes loss of pain perception
Lepromatous: deeply nodular infection that causes severe disfigurement of the face and extremities
Which microorganism causes fish tank granuloma?
Mycobacterium marinum
What is a scrofula?
Infxn of the cervical lymph nodes in children caused by M. scrofulaceum, MAC, and other nonTB mycobacteria
Describe the morphology of Pseudomonas aeruginosa.
G- rod w/ single polar flagellum
What is the cytotoxic pigment produced by P. aeruginosa that is responsible for bluish- green exudates?
Oxidase and catalase pigments
Which underlying conditions are most P. Aeruginosa nosocomial infections associated with?
Severe burns, neoplastic disease, premature birth, cystic fibrosis
What is the name of the folliculitis caused by P. aeruginosa?
Hot tub folliculitis
Describe hot-tub folliculitis, how soon it appears after exposure, and where the rash is most commonly located.
Pruritic pustules w/ central punctum on erythematous base present 24 hours after exposure, commonly on the flanks, axillae, buttocks, or any location occluded by swimwear
Why are puncture wounds through a rubber sole shoe associated with P. aeruginosa?
P. aeruginosa thrives in moist environments, the rubber sole provides a warm, damp habitat
List other common P. aeruginosa infections that occur in immunocompetent individuals.
Otitis externa, corneal ulcers w/ contact lens, UTI
Which opportunistic pathogen is the cause of Melioidosis?
Burkholderia pseudomallei
What is another name for Melioidosis and what symptoms are associated with it?
Whitmore’s disease: HA, fever, chills, cough, chest pain
List the three pathogens that cause Brucellosis and which animal each one is commonly associated with.
Brucella abortus (cattle), brucella suis (pigs), brucella melitensis (sheep)
What are undulant fevers?
Fluctuating pattern of fever for weeks to months
Which bacteria causes tularemia?
Francisella tularensis
What is another name for tularemia?
Rabbit fever
Describe the portal of entry and symptoms associated with ulceroglandular tularemia
tick or fly bite; skin ulcer at the site
Describe the portal of entry and symptoms associated with oculoglandular tularemia
bacteria enters through the eye; conjunctival inflammation
Describe the portal of entry and symptoms associated with oropharyngeal tularemia
eating or drinking contaminated food; sore throat, oral ulcers, cervical LAD
Describe the portal of entry and symptoms associated with pneumonic tularemia.
inhalation of aerosols, most serious form; cough, chest pain
Which pathogen causes pertussis?
Bordetella pertussis
What is another name for pertussis?
Whooping cough
Is pertussis contagious? What type of pulmonary condition does it cause?
Yes very, tracheobronchitis
List the three phases of pertussis
Catarrhal, Paroxysmal, Convalescent
What are the symptoms for the catarrhal stage of pertussis?
1-2 weeks of sneezing coryza, night cough, inject conjunctiva (most infectious)
What are the symptoms for the paroxysmal stage of pertussis?
paroxysmal coughing followed by a high pitched whoop or staccato cough, fever resolves
What are the symptoms for the convalescent stage of pertussis?
4 weeks after onset and dec in frequency and severity of cough
What is the antimicrobial treatment of choice for pertussis: children and adults?
Azithromycin or clarithromycin x 1 week; if allergy, Bactrim DS
Describe the morphology of Legionella pneumophila.
G- motile rods that range in morphology from cocci to filaments
List different water sources Legionella could be found.
Tap water, cooling towers, spas, ponds, other fresh water; also in A/C systems
List the two infections caused by L. pneumophilia. What is the difference between the two?
Legionnaire’s disease & Pontiac fever (Less severe form of infection that does not cause pneumonia)
Which family is the largest group of gram-negative bacteria?
Enterobacteriaceae aka enterics
Describe the morphology of enterobactriaceae
Small, non-spore forming rods. Facultative anaerobes
Which enteric pathogen has the highest percentage of nosocomial infections?
Gram -
Which enteric pathogen is responsible for ~70% of traveler’s diarrhea and >50% of UTIs?
E. Coli
List the six pathotypes of E. coli that cause traveler’s diarrhea. (Name and abbreviation)
Enterotoxigenic E. Coli (ETEC)
Enteroinvasive E. coli (EIEC)
Enterohemorrhaic E. coli (EHEC, E.coli O157:H7) or Shiga toxin producing E.Coli (STEC)
Enteropathogenic E. coli (EPEC)
Enteroaggregative E. coli (EAEC)
Diffusely adherent E. coli (DAEC)
Which enteric pathogen strain is associated with hemorrhagic colitis and hemolytic uremic syndrome?
Enterohemorrhaic E. coli (shiga toxin producing)
Which non-lactose fermenting true pathogen is associated with animal bites?
Pasteurella multocida
What is the first line antibiotic used for animal bites?
Augmentin
Which pathogen causes typhoid fever?
Salmonella typhi
What is the most common form of transmission of typhoid?
Food and water contaminated with fecal matter
When bacteria invade the small intestinal lining, what changes are observed?
Bacteria enter the bloodstream causing bacteremia and endotoxemia. Ulceration and perforation due to infection of the lymphatic tissue of the small intestine
Non-typhoid salmonellosis causes food poisoning. What symptoms are associated with this infection?
Nausea, vomiting, fever, diarrhea (watery or bloody), abdominal cramping
How long does it take to recover typically from non-typhoid salmonellosis?
Most recover within 4-7 days without abx
Are antibiotics needed for non-typhoid salmonellosis?
If patient is stupid and doesn't know how to heal, Ciprofloxacin or levofloxacin for adults, azithromycin for children
Which Shigella species causes the most severe infection?
S. Dysenteriae
Describe the diarrhea associated with Shigella.
Watery stool filled with mucus and blood
Describe the appearance of the large bowel lining when infected with Shigella.
Erosion of the lining of the large bowel and points of hemorrhage that release bloody discharge. Does not cause perforation
Which pathogen is responsible for the Bubonic Plague?
Yersinia pestis
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