Bacteria Flashcards
Listeria Monocytogenes
- Motile
- Fac anaerobe
- Catalase +
*Grows at cold temp
Transmission: - Vertical
- Food borne (dairy products, soft cheeses, deli meats, contaminated veggies)
- Immunosuppressed (transplant, steroid, cancer/chemo) & old/young
Disease: - Most virulent (20-30% result in death of high risk pts)
- Pregnant mothers: influenza-like symptoms; HA, malaise, fever, backache, nausea, chills, diarrhea
- infects placenta & fetus
- can cause premature labor
*Adult: Self limited GI illness (24 hr after ingestion) or invasive disease (30 days after); sepsis and/or meningitis
Neonatal Listeriosis:
* Early onset (< 5d): sepsis or meningitis
*Late onset (>5d): purulent meningitis
* Microabscesses/granulomas in organs
* Most have underlying immunodeficiency
Diagnosis: Blood culture, CSF, skin lesion cultures
Treatment: Ampicillin + Gentamicin
Gram pos rods
Bacillus anthrasis
*Spore forming
*Fac anaerobe
* Non-motile
* Protein capsule (Glu)
*Boxcar shape (spore in center)
Transmission:
* Animals or animal products
* Exotoxins (A-B)
* Cutaneous, inhalation & GI
Virulence Factors:
* Anthrax toxin –> Edema
Disease:
* Painless papule at entry site –> eschar
*Bacteria can spread via lymphatics causing severe disease & death
*Airborne exposure to spores –> pneumonia, mediastinal hemorrhage, bloodstream infection, death
Diagnosis:
* Skin/blood culture
*PCR
Treatment:
* Ciprofloxacin (penicillin & doxycycline)
*Systemic antibiotic if cutaneous anthrax (20% chance of dissemination)
Vaccine:
*Vaccine exists
Gram pos rods
Bacillus cereus
”* Spore forming
* Motile
B-hemolytic
* Fac anaerobe”
Transmission:Reheated rice
Virulence Factors:” Pre-formed enterotoxin: heat-stable, water soluble exotoxin; forms pores in cell membranes of cells lining intestine; inactivated when heated to 133’F
Cereulide: toxin that is NOT heat inactivated; leads to emetic form (vomiting)”
Disease:” Food poisoning: Spores germinate in food that sits out exposed to environment & cause N/V 1-6 hr after and diarrheal toxin 8-16 hr after ingestion
* Excessive amt of toxin can mimic sepsis”
Diagnosis:
Treatment:
Gram pos rods
Corneybacterium diphtheria
”* V shape
* Pleomorphic
Non-motile
* Fac anaerobe
* Catalase +”
Transmission:
Virulence Factors: “ Diphtheria toxin (A-B toxin)
*Exotoxin encoded by bacteriophage that inactivates EF-2, inhibiting protein synthesis”
Disease: “Diphteria:
* sore throat, swollen glands, difficulty breathing, fever, malaise
*Bull’s neck
Pseudomembranous pharyngitis (grey-white membrane) with lymphadenopathy, myocarditis, arrhythmias”
Diagnosis:
Treatment: “Diptheria antitoxin (DAT)
*Erythromycin or penicillin”
* DTaP vaccine
Gram pos rods
Clostridium tetani
”* Club shaped
* Terminal spore
* Ob anaerobe
Motile
B-hemolytic”
Transmission: “ Spores persist for months
* NOT transmitted btw pts”
Virulence Factors: “ Tetanus toxin (A-B toxin)
* Tetanospasmin: neurotoxin”
Disease: “Tetanus
* Binds gangliosides at neural junction of skeletal muscles & neuronal membranes in spinal cord –> inhibits release of inhibitory neurotransmitters (GABA)
* Spastic paralysis, muscle rigidity, lockjaw”
Diagnosis:
Treatment:
”* DTaP vaccine
*10 yr booster shots”
Gram pos rods
Clostridium difficile
”* Club shaped
* Terminal spore
* Ob anaerobe
* Motile
* capsule”
Transmission:
Virulence Factors: * Enterotoxin A & B
Disease: Pseudomembranous colitis
Diagnosis:
Treatment:
Gram pos rods
Clostridium botulinum
”* Club shaped
* Terminal spore
* Ob anaerobe
* Motile
* B-hemolytic”
Transmission: *Home canned food containing toxins
Virulence Factors: * Botulinum toxin (A-B toxin): absorbed from gut & blocks neurotransmission at peripehral nerve synapses
Disease: Botulism
* Flaccid paralysis, muscle weakness, resp arrest, descending paralysis
*neuro sx 12-36 after toxin ingestion
* NO fever & pt remains responsive
Infant Botulism: Flaccid paralysis with ingestion of honey containing spores
Wound Botulism: contamination of open wound w spores; same presentation,
Diagnosis:
Treatment: “* Antitoxin
*Supportive care
* Spontaneous recovery can take up to 100 days
* Wound: debridement, penicillin + antitoxin”
Gram pos rods
Clostridium perfringens
”* Club shaped
* Terminal spore
* Ob anaerobe
* B-hemolytic
* Non-motile”
Transmission: Preformed toxin in gravies/meats
Virulence Factors: * Alpha toxin
Disease: “ Gas gangrene
* Food poisoning: watery, foul smelling diarrhea 8-16 hr after ingestion due to spore or preformed toxin contaminating food (possibly bloody)”
Diagnosis:
Treatment:
Gram pos rods
Streptococci
- Catalase neg
Transmission:
Virulence Factors:
Disease:
Diagnosis:
Treatment:
Gram pos cocci
S. mitis (viridans)
”* A-hemolytic
* Fac anaerobe
* Optochin R”
Transmission: *Oral microbiota
Virulence Factors:
Disease: *Endocarditis (synthesizes dextran from glucose & use to adhere to fibrin-plt aggregates on damaged heart valves)
Diagnosis:
Treatment:
Gram pos rods
S. mutans (viridans)
”* A-hemolytic
* Fac anaerobe
Optochin R”
Transmission:
Virulence Factors:
Disease: “ Dental carries
*Endocarditis (synthesizes dextran from glucose & use to adhere to fibrin-plt aggregates on damaged heart valves)”
Diagnosis:
Treatment:
Gram pos rods
S. pneumoniae
”* A-hemolytic
* Fac anaerobe
* Capsule
* Lancet shaped diplococci
* Optochin S”
Transmission: “* Resp transmission
* Risk factors: asplenia, smoker, CSF leak, cochlear implant, SCD, HIV, day care”
Virulence Factors: * Capsule
Disease: “* Most common cause of pneumonia & bacteria meningitis
* C-MOPS: conjunctivitis, meningitis, otitis media, pneumonia (lobar), sinusitis, septicemia”
Diagnosis:
Treatment:
”* PPSV23 (Pneumovax): polysaccharide vaccine
- > 65 yo & > 2 yo if at increased risk
- Not for < 2 yo
- Less effective in preventing pneumonia
* PCV13: Conjugated to diphtheria toxin
- infants & adults > 65 yo”
Gram pos rods
S. pyogenes (GAS)
”* B-hemolytic
* Fac anaerobe
* Capsule
* Chains
* Bacitracin S
* Pyogenic (pus)”
Transmission: * Usually children 4-8 yo
Virulence Factors: “* Erythogenic exotoxin A (produced when infected w certain bacteriphage; skin rash/fever of scarlet fever & superantigen that causes proliferation of T cells & cytokines –> shock)
SpeA, SpeB (TSS)
* Streptolysin O/S (hemolysis)”
Disease: “ Pharyngitis (strep throat), cellulitis, PSGN, necrotizing fasciitis, rheumatic fever
* Scarlet Fever: pharyngitis, fever then diffuse palpable, sandpaper-like eruption starting on abdomen & disseminates (4-8 yo), strawberry tongue, normal conjunctiva/lips, desquamation during recovery
*Toxic Shock Syndrome (SpeA & SpeB) –> erythroderma (sunburn-like diffuse reddening of skin)
Compared to Staph: 20-50 yo, equal sex, severe pain common, erytheroderma (sunburn like reddening of skin) less common, higher bacteremia, tissue necrosis more common, cuts/burns predispose pt, higher mortality rate”
Diagnosis:
Treatment: “* Penicillin
*IVIG”
Gram pos rods
S. agalactiae (GBS)
”* B-hemolytic
* Fac anaerobe
* Capsule
* Chains
* Bacitracin R”
Transmission: “GI/GU microbiota
* Acquired during vaginal birth (50% w/o intrapartum abx)”
Virulence Factors:
Disease: “Adults: UTIs, skin/soft tissue infections, osteomyelitis, meningitis, endocarditis
Neonatal Infection:
* Early onset (< 7 days): septicemia, pneumonia, meningitis
* Late onset (7-89 days): Bacteremia w/o focus, meningitis, osteomyelitis, pyogenic arthritis, cellulitis, adenitis
*Major cause of bacterial neonatal sepsis, pneumonia, meningitis”
Diagnosis:
Treatment:
Gram pos rods
S. bovis (GDS)
”* y-hemolytic
* Oxidase neg
* Doesn’t grow on NaCl”
Transmission: “* GI microbiota
* Cattle feces”
Virulence Factors:
Disease: “* Endocarditis, sepsis, UTIs
* rarely neonatal sepsis & meningitis”
Diagnosis:
Treatment:
Gram pos rods
Enterococcus faecalis & faecium
”* y-hemolytic
* Fac anaerobe
* Oxidase neg
* Bile R
* Grows in NaCl
* Yellow on mannitol (faecalis)”
Transmission: “* Persist on fomites
* E. faecalis is more common
* E. faecium is more likely to be VRE (ESKAPE pathogen)”
Virulence Factors:
Disease: * UTIs, peritonitis (abdominal swelling/tenderness, fever), wound infections, bacteremia
Diagnosis:
Treatment:
Gram pos rods
Staphylococcus aureus
“Catalase +
B-hemolytic
* Fac anaerobe
*Coagulase +
* Capsule”
Transmission: “ Skin flora (ESKAPE pathogen)
* Contaminated high protein foods, creat or egg based dishes”
Virulence Factors: “ A-toxin (hemolysis)
*B-toxin (sphingomyelinase)
* Hemolysin (hemolysis)
* Leukocidin (destroys leukocytes)
* Enterotoxins (heat-stable, food poisoning)
TSST-1 (superantigen, release of cytokines -> TSS)
* Epidermolytic/exfoliative (epithelial cell lysis, scalded skin syndrome)”
Disease: “ Inflammation –> pus, tissue necrosis, boil/abscess formation
* Minor skin infections (pimples, impetigo, boils, cellulitis, abscesses)
* Serious: osteomyelitis, pneumonia, meningitis, gastroenteritis, endocarditis, bacteremia
*TSS: Diffuse inflammatory response with fever, rash, hypotension & multi-organ involvement (TSST-1); erythroderma in 24-48 hr
* Scalded Skin Syndrome: Exfoliative toxins A & B act at remote site targeting desmoglein-1 (cell-cell attachment in epidermis); low grade fever followed by skin peeling & red/tender areas; rash spreads to other parts of body; desquamation during crescendo phase
- Nikolsky Sign: cleavage of stratum granulosum layer of epidermis
*Food poisoning: N/V 3-4 hr after ingestion that resolves within 24 hr (NOT diarrhea which IS seen w Bacillus cereus & Clostridium perfringens)
Compared to GAS: Mainly 15-35 yo, women more often, rarely severe pain, erytherodema (sunburn like reddening of skin) very common, low bacteremia, tissue necrosis rarely, tampons/varicella predispose pt, low mortality rate”
Diagnosis:
Treatment:
Gram pos rods
S. epidermidis & saprophyticus (CoNS)
”* Catalase +
* y-hemolytic
* Fac anaerobe
* Coagulase neg
* Forms biofilm”
Transmission:
Virulence Factors:
Disease: “* Endocarditis, UTIs, osteomyelitis
* S epidermidis: intravascular device, prosthetic joints, catheter, wound infections; produces polysaccharide adhesin that aids in attachment to surfaces
*S saprophyticus: Most common gram + cause of UTIs (novobiocin R)”
Diagnosis:
Treatment:
Gram pos rods
Nocardia spp
“*Aerobe
*Catalase +
Partially acid fast”
Transmission: “Soil
*Oral microbiome”
Virulence Factors:
Disease: * Nardiosis: pulmonary virulent form of pneumonia or meningitis in immuncompromised
Diagnosis:
Treatment:
Gram Pos Branching
Actinomyces isrealii
”* Oblgate anaerobe
* Catalase variable
* NOT acid fast”
Transmission: “* Vaginal, oral or GI microbiome
*Soil”
Virulence Factors:
Disease: * Actinomycosis: formation of abscesses in mouth, lungs or GI tract in immunocompromised
Diagnosis:
Treatment:
Gram Pos Branching
Neisseria meningitidis
”* Aerobe
* Capsule
Catalase +
Oxidase +
* Serogroups based on capsule”
Transmission: “Nasopharynx of some
* Resp transmission
* Risk factors: sub-Saharan Africa, terminal comp def, asplenia, Properiden def, HIV, Eculizumab”
Virulence Factors: “Direct contact, resp trasmission
* Risk factors: late comp deficiency, asplenia, close contact”
Disease: “* Meningitis & meningococcemia
*Abrupt onset w fever, chills, malaise, myalgia, limb pain, prostration, rash
* Maculopapular rash –> petechial –> purpura
* Purpura fulminans: cutaneous hemorrhage & tissue necrosis, hypotension, DIC, sepsis
Most invasive serogroups: A, B, C, Y, W-135”
Diagnosis:
Treatment: “ Rifampin, Ciprofloxacin or Ceftriaxone: PPX for close contacts
*3rd gen cephalosporin”
Vaccine: “Do NOT protect against Men B:
* Quad Men Conjugate Vaccine (MCV4, Menactra, Menveo): Polysaccharide conjugated to diptheria toxoid that targets A, C, Y, W-135 (2 mo-55 yo)
- 11-12 yo + booster at 16 yo
* MENHIBRIX: Men C/Y, HiB, tetanus toxoid conjugate vaccine (6wk-18mo)
Men B Protection:
*Bexsero/Trumenba: 16-18 yo; used in those at increased risk at > 10 yo; many colleges require it”
Gram Neg Diplococci
Neisseria gonorrhoeae
”* Aerobe
*Non-motile
* Non spore forming
* Oxidase +
*Kidney bean shape”
Transmission:
Virulence Factors: *Varies surface antigens (evades immune system)
Disease: “Gonorrhea:
* Women more asymptomatic than men
* Can cause disseminated disease
* Urethritis: discharge, dysuria, pruritus
*Cervicitis: discharge, intermenstrual bleeding”
Diagnosis: Cervicitis: gram stain, wet mount, NAAT, culture, PCR
Treatment: “ Ceftriaxone (uncomplicated GC of cervix, urethra, rectum)
*Doxyclcine for chlamydia if not excluded”
Gram Neg Diplococci
Bordetella pertussis
“Aerobe
* Catalase +
* Oxidase +
* B-hemolytic
* Capsule”
Transmission: “ Resp transmission
* Incubation period = 5-10 days”
Virulence Factors: “* Adhesion: fimbrae, adhesins (petractin, filamentous hemagglutinin)
*Exotoxins: Tracheal cytotoxin, pertussis toxin (A-B toxin), adenylate cyclase toxin”
Disease: “Whooping cough:
* Catarrhal stage: URI (1-2 wk) –> Paroxysmal stage: inspiratory whoop w vomiting (1-6 wk)–> Convalescent stage: symptoms wane (wk-mo)
* Pertussis toxin inhibits Gi proteins –> overactive adenylate cyclase –> high cAMP causing impaired recruitment of neutrophils
* Bacteria attach to cilia of resp epithelial cells
* Complications in young: apnea, pneumonia, seizures, death, encephalopathy
* Complications in adults: pneumonia, rib fracture, weight loss, hernia, urinary incontinence”
Diagnosis:
Treatment:
”* DTaP vaccine (acellular vaccine)
* Every pregnancy to protect fetus”
Gram Neg Coccobacilli
Haemophilus influenzae
”* Chocolate agar (Requires factor 5-NAD, 10-hematin)
* Fac anaerobe
Capsule
Oxidase +
* Coccobacillary”
Transmission: “ Aerosol transmission
Risk factors: < 4 yo, SCD/asplenia, HIV, Native American”
Virulence Factors:
Disease: “Type B strains are most invasive; non-typable strains cause mucosal infections (OM, bronchitis)
* EMOP: Epiglottitis, Meningitis, OM, Pneumonia
* Causes severe infection in infants: bacteremia, septic arthritis, cellulitis, purulent pericarditis
* Unencapsulated strains cause OM, conjunctivitis, sinusitis in children (unaffected by vaccine)
* Does NOT cause flu”
Diagnosis:
Treatment: “ Rifampin: PPX for close contact
*Amoxicillin for mucosal infections??? (Sketchy)”
* HiB vaccine: contains type B capsular polysaccharide (PRP) conjugated to diptheria toxoid or another protein
Gram Neg Coccobacilli
Haemophilus ducreyi
“*Fastidious
Fac anaerobe
* Choc agar only”
Transmission:
Virulence Factors:
Disease: Chancroid: PAINFUL genital ulcer & tender suppurative inguinal lymphadenopathy
Diagnosis: “ Microscopy/Ag detection are NOT sensitive nor specific &PCR is NOT FDA approved
All of the following met:
1+ painful ulcers
* Darkfield & serology negative for syphilis
* Negative HSV (ulcer exudate)
* Clinical presentation of genital ulcer + adenopathy”
Treatment:
“ Azithromycin, ceftriaxone, ciprofloxacin, erythromycin
* Sex partners should be examined & treated if sexual contact w pt 10 days preceding onset of symptoms”
Gram Neg Coccobacilli
Francisella tularensis
”* Aerobe
*Coccobacillus
*Non-motile
VERY small
* Difficult to culture”
Transmission: “ Rabbits or tick bite from rabbit
* Enters macrophages –> caseating granuloma”
Virulence Factors:
Disease: “Tularemia: form depends on portal of entry
*Ulceroglandular - skin lesion & LN
* Oculoglandular - eye & cervical LNs
*Glandular - LNs
Typhoidal - fever, sepsis
* Pneumonic - severe w sepsis
* Oropharyngeal/GI disease (after ingestion, RARE)”
Diagnosis: “ Serology
Culture (choc agar, but high risk of spread to lab personnel)”
Treatment: “ Streptomycin
* Gentamicin
* Doxycycline or cipro for milder infections”
Gram Neg Zoonotic
Vibrio vulnificus
6% NaCl
Transmission: “Marine environments
Shellfish/oysters”
Virulence Factors: * Cytolysin, hemolysin, MARTX toxin
Disease: “ Acute gastroenteritis, necrotizing wound infections, invasive species (immunocompromised)
* Systemic illness in those w liver disease or iron storage disorder; Fever, hypotension, bullous skin lesions”
Diagnosis:
Treatment: “* Surgery
*Tetracycline”
Gram Neg Curved Rods
Leptospira interrogans
”* Aerobe
Motile
* 3 mo to grow
* Spirochete”
Transmission: “ Infects dogs, rates, mice
* Transmitted via urine/wet environment”
Virulence Factors:
Disease: “*Leptospirosis: flu-like symptoms, hepatitis, jaundice, renal failure, aseptic meningitis, conjunctival or scleral hemorrhage (biphasic)
Weil’s Disease: severe w hemorrhage, kidney & liver failure”
Diagnosis: “Bacteria can be isolated from blood, CSF, urine
*PCR
* Serology: agglutinating Ab”
Treatment: * Penicillin or doxycycline if started early in course
Gram neg spirochetes
Rickettsiae ricketsii
Transmission:”* Dermacentor tick or lone star tick (must be on person for 6+ hrs)
* Most common in South/Central US
* Most cases Apr-Oct
* Incubation period = 2-14d”
Virulence Factors: * OmpA: outer membrane protein that helps it adhere to endothelial cells causing leaky blood vessels & disease
Disease: “Rocky Mtn Spotted Fever:
Prodrome: Fever, nausea, vomiting, HA, malaise, photophobia
* Bacteria replicate in endothelial cells of vessels, disseminating in blood -> thrombosis & capillary leak -> edema & petechia
* Rash with blanching macules/papules on wrists & ankles -> petechia (2-5 days post-exposure); spreads centrally (spares face)
* Complications: renal failure, pulmonary failure, neuro manifestations, cardiac abnormalities, rapidly fatal”
Diagnosis: “Ab detection
*PCR on skin biopsy”
Treatment: * Doxycycline (do NOT wait for definitive diagnosis or rash bc can be rapidly fatal; not contraindicated for kids under emergent settings)
Gram indeterminant
