ID - Bacterial Infections

1

Less than ___% of bacteria cause disease

3 multiple choice options

circular

Diplo, strepto and staphylo are examples of ___ bacteria

rod

Coccbacilli, streptobacilli and mycobacteria are examples of ___ shaped bacteria

curved

Vibrio, spirilla, and spirochete are examples of ___ shaped bacteria

- direct invasion

- toxin formation

- blood clotting (from toxins)

How do bacteria damage tissue?

Diptheria

Which organism produces toxins that damage the heart muscle by inhibiting protein synthesis?

Staph, strep, and clostridium

Which three bacteria are most common causative agents of disease?

25

Staph aureus is present in about ___% of the population on the skin/nares

staph

A skin and soft tissue infection with associated purulence is likely caused by ___

non-purulent

Erysipelas, cellulitis and necrotizing fasciitis are ___

purulent

Abscesses, furuncles and carbuncles are ___

- oral cephalexin, clindamycin or dicloxacillin

Tx of mild cellulitis, erysipelas or necrotizing infection?

- IV Cloxacillin, cefazolin, clindamycin, penicillin or ceftriaxone

Tx of moderate cellulitis, erysipelas or necrotizing infection?

- empiric Rx (vancomycin + piperacillin/tanzobactam)

Tx of severe cellulitis, erysipelas or necrotizing infection?

- I&D

Tx of mild furuncle, carbuncle, or abscess?

- I&D w/ C&S

- cephalexin or doxy PO or cefazolin IV

Tx of moderate furuncle, carbuncle, or abscess?

- I&D w/ C&S

- IV vancomycin

Tx of severe furuncle, carbuncle, or abscess?

mild symptoms with associated systemic symptoms

What makes a SSTI moderate?

failed abx, failed I&D, systemic symptoms, immunocompromised (DM/HIV), signs of deeper infection, extremes of age, difficulty of complete drainage

What makes an SSTI severe?

Furuncle

What is the diagnosis?

Carbuncle

What is the diagnosis?

CBC w/ diff and blood cultures

What should always be ordered in patients with systemic symptoms?

- Purulence

- penetrating trauma

- IV drug use

- open wound/hardware

- evidence of MRSA elsewhere

- lack of response to beta-lactam

- severe systemic involvement

When should MRSA coverage be added in cellulitis?

- Clindamycin

- TMP-SMX DS

- Doxycycline

What meds have MRSA coverage?

vancomycin and linezolid

Which IV abx are recommended for MRSA?

ceftriaxone (Rocephin) or Cefazolin (Ancef)

IV option for non-MRSA moderate infection

bilateral

Cellulitis is rarely ___ and this can help distinguish it from stasis/contact dermatitis

staph

Pneumonia, infective endocarditis, sepsis and osteomyelitis are other conditions caused by ___

Fournier gangrene

___ is most commonly seen in diabetic males aged 20-50 and presents in the perineal area

E coli, bacteroides, staph, strep, and clostridium

Which microbes can cause fornier gangrene?

- wide emergent I&D

- IV nafcillin or vancomycin

Tx of Fournier gangrene?

Fournier gangrene

What is the diagnosis?

Fournier gangrene

What is the diagnosis?

Staph (60%)

What is the most common causative agent of osteomyelitis?

Osteomyelitis

___ usually involves long bones or vertebrae

Staph aureus

SSSS, enterotoxin food poisoning and TSS can all be caused by

suppression of all immune responses

In TSS staph produces toxins that stimulate T-cells producing cytokines that cause ___

symptoms are due to toxins not an infection

Blood cultures for TSS are often negative because ___

alpha hemolytic

Pneumoniae and viridian are included in ___ strep

Beta hemolytic

Pyogenes and agalactiae are included in ___ strep

Streptococcus pyogenes

Group A beta-hemolytic strep is synonymous with ___

strep pyogenes

Which bacteria is the most common cause of pharyngitis and can cause scarlet fever and impetigo

Erysipelas

Painful superficial cellulitis (usually of the face) with well demarcated borders and a rapid progression

Erysipelas

What is the diagnosis?

Strep pyogenes

Which organism likely caused this condition?

Empyema

What is a pus filled pocket within the pleural space called?

Necrotizing fascitis

Severe rapidly progressing life threatening soft tissue infection with blisters, purple discoloration and crepitus

Necrotizing fascitis

What is the diagnosis?

Necrotizing fascitis

What is the diagnosis?

Type II monomicrobial (Strep pyogenes or staph a)

Which type of NF typically does not form gas?

Type I Polymicrobial

Which type of NF typically affects patients with comorbidities?

Type III Clostridium

Which type of NF occurs after surgery or a penetrating wound?

- broad spectrum abx

- penicillin and clindamycin

- urgent surgical debridement

Tx for suspected NSTI (necrotizing soft tissue infection)

strep pneumoniae

What is the m/c cause of community acquired bacterial pneumonia

strep pneumoniae

what is the most common cause of meningitis in adults

Clostridium botulinum

___ anaerobic spore-forming bacillus found in soil that inhibits the release of acetylcholine if ingested

- food

- infant

- wound

What are the three ways in which botulism occurs?

botulism

Poorly packaged or stored canned, smoked, or vacuumed packed meat fish or vegetables are at risk of ___

honey ingestion

What causes infant botulism?

IV drug use

Wound botulism is rare but occurs most commonly in ___

early findings of botulism

Dry mouth, double vision, ptosis, CN palsy, fixed and dilated pupils, symmetrical cranial nerve impairment with dysphagia, nausea, and vomiting

late findings of botulism

Descending peripheral muscle weakness and respiratory failure

- equine serum heptavalent botulism antitoxin

- contact CDC

- within 24 hours of symptom onset

Tx for botulism?

Clostridium tetani

Spores found in the soil that germinate in open woulds and produce neurotoxins that lead to uncontrolled muscle spasms and exaggerated reflexes

8-12 days

What is the incubation period for tetanus?

Tetanus

Pain and tingling at injury site with spasticity of muscles, neck and jaw stiffness (tismus), dysphagia and tonic convulsions

strychnine poisoning

Tetanus can be confused for ___ and toxicology should rule it out

Tetanus

Risus sardonicus, or peculiar grin, is associated with

- sedation, paralysis and mechanical ventilation

- penicillin 20 million units IV

- human tetanus immune globulin 500 units IM

- immunize after acute phase

Tx for acute tetanus?

clostridium perfringens

Which organism is most associated with gas gangrene?

less than 24 hours

Typical incubation period of gas gangrene?

gas gangrene

Toxins of ___ produce shock, hemolysis, and myonecrosis under anaerobic conditions

Posttraumatic (auto accidents m/c)

Which type of gas gangrene is most common?

Gas gangrene

Sudden onset of pain and heaviness in extremity, low fever, apathetic mental state after a car accident with localized swelling, crepitus, bronze skin, pain, and tachycardia

- penicillin and clindamycin (sub metronidazole for allergies to pcn)

- aggressive surgical debridement

Tx of gas gangrene?

occult malignancy of the GI tract

Spontaneous gas gangrene has a strong association with ___

Corynebacterium diphtheriae

Sore throat, nasal discharge, hoarseness, malaise and fever which can involve the skin cause by exotoxins. Can lead to myocarditis and neuropathy

C. Diphtheriae

Exotoxins of ___ cause myocarditis (arrhythmias, heart block and failure) as well as neuropathy (diplopia, slurred speech and dysphagia)

C. Diphtheriae

What is the diagnosis?

Diphtheria

Gray pseudo membrane covering the tonsils and pharynx is concerning for ___

Diphtheria

Culture of mucosal lesions or nasal discharge using tinsdale agar can be helpful in diagnosing

- antitoxin (diphtheria equine)

- keep airway clear

- penicillin or erythromycin

- respiratory isolation

Tx for diphtheria?

pregnant, immunocompromised, neonates and elderly

Listeria monocytogenes most commonly affects which populations?

Listeria

___ is a food borne organism that can be isolated from soil, water and decaying vegetation and is transmitted to humans via mammals, fish, birds and insects.

diarrhea (resembles a GI illness)

Most common clinical manifestation of listeria is ___

Bacteremia and meningitis

What are the more serious manifestations of Listeria?

- suspicion = IV ampicillin (+/- gentamicin) bactrim if allergic to pcn

- diagnose w/ culture of blood or CSF (tumbling motility)

- isolation not necessary no horizontal transfer

Tx for listerosis?

Enteric typhoid fever

M/c form of salmonellosis

5-14 days

Incubation period of typhoid fever?

Salmonella

___ is an intracellular pathogen which invades and replicates in macrophages, lymph nodes and the spleen

Typhoid fever

Gradual onset malaise, headaches, sore throat, cough, fever, and constipation OR pea soup diarrhea

7-10

After ___ days of typhoid fever infection, fever plateaus patient appears very ill and rose spots develop as well as hepatosplenomegaly, abdominal distention, and occasional bradycardia

Typhoid fever

What is the diagnosis?

- (+) blood culture to diagnose

- abx (ciprofloxacin, levofloxacin and ceftriaxone IV)

- hydration

Tx of typhoid fever?

bacillus anthracis

Anthrax is caused by ___ a gram (+) spore forming aerobic rod

Anthrax

Naturally occurring disease of several domestic farm animals that is transmitted to humans via contaminated animal products, soil inoculation, or IV drug use/inhalation

cutaneous, GI, and inhalation

What are the three main types of anthrax

Cutaneous anthrax

2-12 days after exposure an erythematous papule ulcerates and becomes necrotic to form a painless black eschar. Is fatal within 48 hours if not treated

- PCN

- immunization

- immune serum

Tx of cutaneous anthrax

Inhalational anthrax

Onset of illness within 10 days with 2 stages of severity