Microbio E2: Chap 19-21

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