Bacteriology Flashcards
What is the drug of choice for all rickettsial infections?
Doxycycline
What organism present with atypical pneumonia and associated with atherosclerosis?
Chlamydia pneumoniae
What causes Q fever and has no vector, no rash, no weil-felix reaction and has a 65% mortality?
Coxiella burnetti
What do you call the cross reaction with antigens of OX stains of Proteus vulgaris?
Weil-Felix reaction
What organism causes Cat Scratch Disease?
Bartonella Henselae
Organism that cause mesenteric adenitis (pseudoappendicitis), gram negative rods, oro-fecal route of transmission and domestic animals as reservoir
Yersinia enterocolitica
Organism that is catalase positive and coagulase positive
Staphylococcus aureus
Organism that is catalase positive, coagulase negative, novobiocin sensitive
Staphylococcus epidermidis
Organism that is gram positive cocci in clusters, catalase positive, coagulase negative, and novobiocin resistant
Staphylococcus saprophyticus
Organism that is gram positive cocci in chains, catalase negative, alpha hemolytic, bile-optochin-sensitive
Streptococcus pneumoniae
Gram-negative diplococci Oxidase-positive on chocolate agar Ferments maltose and glucose Complement deficiencies in late-acting complement components (C5-C9)
Neisseria meningitidis
Spectrum of disease of Neisseria menigitidis
Meningitis Meningococcemia Waterhouse-friderichsen syndrome
Neisseria gonorrhoeae is oxidase positive on _____.
Thayer-Martin medium
Treatment of Neisseia gonorheoae when co-infected with Chalmydia trachomatis
Ceftriaxone + doxycycline
Other Neisseriaceae that cause culture-negative subacute bacterial endocarditis in patients with pre-existing heart disease
Eikenella corrodens Kingella kingae
Haemophilus influenzae requires (1) _____ (hemin) and (2) _____ (NAD) for growth on chocolate agar, and causes a Satellite Phenomenon on (3) _____ colonies.
(1) factor X (2) factor V (3) Staphylococcus aureus
This vaccine contains the type b capsular polysaccharide conjugated to diphtheria toxoid, and is given between 2 and 18 months of age.
Haemophilus influenzae b vaccine
Grows on Bordet-Gengou agar or Regan-Lowe charcoal medium Habitat is the upper respiratory tract Transmitted via respiratory droplets Causes whooping cough
Bordetella pertussis
3 most common cause of atypical pneumonia
Mycoplasma pneumoniae Legionela pneumophila Chlamydia pneumoniae
Spectrum of disease of atypical pneumonia in Legionella pneumophila
Pneumonia Confusion Nonbloody diarrhea Hyponatremia Proteinuria Hematuria
Facultative intracellular bacteria
Some Bugs May Live FacultativeLY Salmonella Brucella Mycobacterium Listeria Francisella Legionella Yersinia
Lactose-fermenting colonies on Eosin-Methylene Blue or MacConkey’s agar Triple sugar iron agar shows acid slant and acid butt with gas but no H2S Typing by O and H antigen Most common cause of community-acquired UTI Second most common cause of Neonatal meningitis
Escherichia coli
Match the antigen with the pathogen Antigen: H, K, O Pathogen: capsule, endotoxin, flagellum
Flagellum - H Capsule - K Endotoxin - O
Treatment for Escherichia coli infection (1) worldwide (2) Philippines
(1) ampicillin or sulfonamides (UTI), 3rd generation for meningitis and sepsis (2) quinolones
Antigen that causes typhoid fever that can result in the establishment of a chronic carrier state
Vi capsular antigen
Incubation period of 12-48 hours Nausea and vomiting and then progresses to abdominal pain and nonbloody diarrhea
Enterocolitis (Salmonella enteritidis / Salmonella typhimurium)
Chloramphenicol is used for the treatment of Salmonella infection. It is also used for the empiric treatment of meningitis. What are the other common causes of meningitis?
Neisseria meningitidis Bacteroides fragilis Streptococcus pneumoniae Haemophilus influenzae
Shigella dysenteriae type 1: _____ bacillus Shigella sonnei: _____ bacillus
Shiga bacillus Duval’s bacillus
Non-lactose fermenting, gram-negative rods Produce no gas from the fermentation of glucose Do not produce H2S Nonmotile Have O antigens Cultured inXLD medium
Shigella spp.
Habitat: saltwater Transmission: contaminated raw seafood Spectrum of disease: gastroenteritis, wound infections
Vibrio parahaemolyticus
Enterotoxin of Vibrio that acts by ADP-ribosylation
Choleragen
Most common cause of bacterial gastroenteritis Produces histologic damage to the mucosal surafces of the jejunum Watery, foul-smelling diarrhea followed by bloody stools Associated with Guillain-Barrè syndrome and Reiter’s syndrome
Campylobacter jejuni
Urease-positive bacteria
Particular Kinds Have Urease Proteus mirabilis Klebsiella pneumoniae Helicobacter pylori Ureaplasma urealyticum
Facultative gram-negative rods with large polysaccharide capsule Extended spectrum beta-lactamase activity in drug-resistant strains Urease-positive Necrotizing pneumonia with currant-jelly sputum
Klebsiella pneumoniae
Proteus mirabilis isnassociated with complicated UTI, particularly those that form staghorn calculi on renal calyces. What type of motility is exhibited by this bacteria?
Swarming motility
Gram-negative rods Obligate aerobe Non-lactose fermenting Oxidase-positive Grown on Cetrimide agar Seen in many diseases such as: hot tub folliculitis, burn wound infections, otitis externa, CSOM, VAP, high-risk CAP, tyhplitis, Shanghai fever, perionitis (in those undergoing PD), nosocomial UTI, ecthyma gangrenosum
Psudomonas aeruginosa
Toxin of Pseudomonas aeruginosa that causes tissue necrosis and inactivates EF-2, with type III secretion systemthat facilitates the toxin’s transfer
Exotoxin A
Grape-like clusters Beta hemolytic yellow or golden colonies on blood agar Catalase and coagulase positive Salt tolerant on 1)_______ Gold color due to 2) ________ What is this organism?
1) Mannitol Salt Agar 2) Staphyloxanthin pigment Staphylococcus Aureus
This organism has Protein A, Coagulase, Hemolysins, PV Leukocidin, Catalase, and Penicillinase. What is the organism and what do you call these immunomodulators?
Staphylococcus aureus and these are immunomodulators. (Note: Definition of Terms Protein A: Prevents complement activation Coagulase:Builds an insoluble fibrin capsule Hemolysins: Toxic to hematopoietic cells PV leukocidin: Specific for white blood cells Catalase:Detoxifies hydrogen peroxide Penicillinase: Inactivates penicillin derivatives)
This organism can hydrolyze hyaluronic acid, dissolve fibrin clot and spread in fat-containing areas of the body. It can also cause epidermal separation, necrosis of the skin and hemolysis, cause food poisoning and can lead to TSS. What is this?
Staphylococcus aureus [Note: Definition of Terms Hyaluronidase: hydrolyzes hyaluronic acid Fibrinolysin/Staphylokinase: dissolves fibrin clot Lipase: spread in fat-containing areas of the body Exfollatin: causes epidermal separation Heat-stable Enterotoxins: superantigens causing food poisoning Toxic Shock Syndrome toxin (TSST-1): superantigen leading to TSS Alpha Toxin: causes marked necrosis of the skin and hemolysis]
Most common cause of acute endocarditis and what valve is usually involved in IV drug abusers? Also causes penumonia, osteomyelitis, brodie abscess and septic arthritis.
Staphylococcus aureus Tricuspid valve (Brodie abscess: sequestered focus of osteomyelitis arising in the metaphyseal area of a long bone)
Causes bullous impetigo, folliculitis, furuncles, carbuncles, cellulitis, hidradenitis suppurativa, mastitis and surgical site infections.
Staphylococcus aureus (Examples of skin and soft tissue infections caused by S. aureus)
Treatment for S. aureus? MSSA, MRSA and VRSA
Methicillin sensitive: penicillinase-resistant penicillins like Nafcillin, Oxacillin and Dicloxacillin Methicillin resistant: Vancomycin Vancomycin resistant: Linezolid
Fever, hypotension, sloughing off of the filiform papillae in the tongue, desquamating rash, multi-organ involvement, blood CS negative What presents with these and what is the organism responsible?
Toxic shock syndrome Staph aureus (Note: due to TSST-1 Usually there is no site of pyogenic inflammation that’s why blood CS is negative Usual patients are those that uses tampons and who have nasal packing)
Difference of TEN and Ritter disease?
Both affects the skin Ritter: separation of epidermis at STRATUM GRANULOSUM because exfollatin cleaves desmoglein in desmosomes. Organism involved is Staph aureus TEN: separation occurs at the dermo-epidermal junction Ritter disease is Scalded Skin Syndrome TEN is Toxic Epidermal Necrolysis
Low virulence organism Forms biofilm because its glycocalyx adheres well to foreign bodies Transmitted through autoinfection or direct contact What is the organism and what are the diseases it causes?
Staphylococcus Epidermidis It is the most common cause of: Prosthetic valve endocarditis Septic arthritis in prosthetic joints Ventriculoperitoneal shunt infections
Gram positive cocci in clusters Catalase positive Coagulase negative Novobiocin sensitive Normal skin flora What is the treatment if you get infected?
Removal of prosthetic device Vancomycin because over 50% are methicillin resistant (Organism: Staph epidermidis)
What is the 2nd most common cause of UTIs in sexually active women?
Staphylococcus saprophyticus (#1: E. coli)
Gram-negative rods Predominant anearobe of human colon Associated with spread during bowel trauma, perforation or surgery Infections due to combinations of bacteria in synergistic pathogenicity
Bacteroides fragilis
Zoonoses
Bugs From Your Pets Brucella abortus (Bruce the cow) Francisella tularensis (Francis the rabbit) Yersinia pestis (Yeye the rat) Pasteurella multocida (Papa the cat)
Brucellosis is associated with undulating fever. What medium is used to identify this organism?
Castañeda medium
Treatment for Tularemia from Francisella tularensis
Streptomycin / Gentamicin
What disease did Yersinia pestis cause that made it the most virulent bacteria?
Bubonic, pbeumonic and septicemic plague
The buttery colonies with musty odor in Pasteurella multocida infection is due to?
Indole production
Mycobacterium tubeculosis uses (1) What stain? (2) What medium? (3) What assay for drug resistance?
(1) Zieh-Neelsen or Kinyoun stain (2) Löwenstein-Jensen medium (3) Luciferase assay
Mycobacterium tuberculosis virulence factors: (1) exported repetitive protein that prevents phagosome-lysosomal fusion (2) most important virulence factor (3) elicits delayed hypersensitivity
(1) sulfatides (2) cord factor (3) tuberculin surface protein
In Mycobacterium tuberculosis, (1) granulomatous lesions exhibit a central area of these cells surrounded by a zone of epithelioid cells = _____ (2) primary complex have subpleural granuloma + associated lymph node = _____ (3) reactivation tuberculosis is usually occurs in apices and is seen as this = _____
(1) Langhan’s giant cells (2) Ghon’s complex (3) Simon’s focus
This bacteria causes pulmonary disease in the immunocompromised, most especially AIDS patients with CD4 < 50
Mycobacterium avium - intracellulare complex
(1) This bacteria’s reservoir are humans and armadillos. One of its spectrum of disease exhibits the following characteristics: (a) few lesions, little tissue destruction, few AFB, low likelihood of transmission, with cell-mediated response to the bacteria, positive skin test (b) many lesions, marked tissue destruction, many AFB, high likelihood of transmission, reduced cell-mediated response to the bacteria, negative skin test
(1) Mycobacterium leprae (a) Tuberculoid leprosy (b) Lepromatous leprosy
Hard, nontender swelling with sinus tracts draining sulfur granules Treated with Penicillin G + drainage
Actinomycosis (Actinomycoses israelii)
Obligate intracellular bacteria
Ricketssia Chlamydia
Cell wall lacks muramic acid Grown in cycloheximide culture Cytoplasmic inclusions in Giemsa Balance is often reached between host and parasite, resulting in prolonged persistance of infection Infection persists in the presence of high antibody titers This organism has 2 forms: (1) inactive, extracellular, enters cells by endocytosis (2) metabolically active, intracellular, seen microscopically as inclusion bodies
Chlamydia trachomatis (1) elementary body (2) reticulate body
Spectrum of disease of Chlamydia trachomatis (1) types A-C, chronic keratoconjunctivitis, Halberstadter-Prowazek inclusions (2) types D-K, most common cause of STDs, neonatal conjunctivitis (ophthalmia neonatorum), neonatal pneumonia, associated with Reiter’s syndrome (3) types L1-L3, buboes (papule or vesicles which ulcerates and leads to suppurative inguinal lymphadenitis), positive Frei test
(1) Trachoma (2) Genital tract infections (3) Lymphogranuloma venereum
Atypical pneumonia associated with atherosclerosis
Chlamydia pneumoniae
Bird fancier’s disease
Psittacosis (Chlamydia Psittaci)
Generalization of treatment for Chlamydia STD : _____ _____ : erythromycin _____ : doxycycline Psittacosis : _____
STD : azithromycin Conjunctivitis : erythromycin LGV : doxycycline Psittacosis : azithromycin
Rickettsiae is classically detected using _____, which is done by the cross-reaction with antigens of OX strains of Proteus vulgaris.
Weil-Felix reaction
Cat-scratch fever in immunocompetent individuals Bacillary angiomatosis in immunocompromised
Bartonella henselae
Transmitted by dog tick bite Forms morulae in cytoplasm of monocytes
Ehrlichiosis (Ehrlichia chaffensis)
Signs of bacterial vaginosis or infection with Gardenella vaginosis
Presence of clue cells Positive whiff test Malodorous vaginal discharge
Chancroid is characterized with painful genital ulcer and presence of heme (factor X) on chocolate agar. What bacteria causes this disease?
Haemophilus ducreyi
Staphylococcus aureus is able to prevent complement activation die to which virulence factor.
Protein A
S. aureus exhibits which pattern of hemolysis when grown on blood agar? What do colonies look like?
B-hemolysis. Yellow or golden colonies due to staphyloxanthin
Gram positive cocci in clusters Catalase positive Coagulase negative Novobiocin resistant Whitish, non hemolytic colonies on blood agar What is the organism and its treatment?
Staphylococcus saprophyticus TMP-SMX or Quinolones
Measures hydrolysis of 1-pyrrolidonyl-Beta-naphthylakide and release of Beta-naphthylamine, which in the presence of p-dimethylaminocinnamaldehyde forms a red compound. What is this test and what it implies?
PYR test If positive (red) then the organism is either S. pyogenes or group D streptococci. If negative then all the other streptococci. It only takes less than a minute to perform this test.
Gram positive cocci in chains Beta hemolytic Catalase negative Bacitracin sensitive Lancefield group A PYR test positive
Streptococcus pyogenes
__________: Degrade hyaluronic acid Streptokinase/Fibrinolysin: ____________ Degrade DNA in exudates or necrotic tissue Inactivate complement C5A _______: produce scarlet fever Rapidly destroy tissue It is highly antigenic, causes AB formation and has a superantigen similar to TSST What is the organism?
Streptococcus pyogenes Hyaluronidase: Degrade hyaluronic acid Streptokinase/Fibrinolysin: Activate plasminogen DNase/Streptodornase: Degrade DNA in exudates or necrotic tissue C5A peptidase: Inactivate complement C5A Erythrogenic toxin: Produce Scarlet Fever Exotoxin B: protease that rapidly destroys tissue Streptolysin O: highly antigenic, causes AB formation Pyogenic exotoxin A: superantigen similar to TSST
_________: titers to document antecedent pharyngitis _________: titers to document antecedent skin infection _________: decrease efficacy of streptokinase in managing MI
Antistreptolysin O Anti-DNase B Antistreptokinase antibodies (We don’t use ASO to document antecedent skin infections because streptolysin O is IRREVERSIBLY inhibited by cholesterol in skin lipids)
Pseudoappendicitis common in children caused by Yersinia enterocolitica Tranmission: oro-fecal route Reservoir: domestic animals
Mesenteric adenitis
Encapsulated, pleomorphic gram-negative bacillus Small painless papule ulcerates to form beefy red ulcer with velvety surface Pseudobobe formation Bipolar densities (_____)
Granuloma inguinale / Donovanosis (Klebsiella granulomatis) Donovan bodies
Weakly acid-fast with Fite-Faraco stain Manifests as mycetomas and lung & brain abscesses (orange colonies) Treated with TMP-SMX + drainage
Nocardiosis (Nocardia Asteroides)
Smallest free-living organism Obligate aerobe No cell wall Only bacteria with sterol on cell membrane Cultured on _____ medium Most common cause of atypical pneumoniae
Mycoplasma pneumoniae Eaton’s medium
Autoantibodies against red blood cells in Mycoplasma pneumoniae
Cold agglutinins
Treponema pallidum cannot be cultured in vitro because _____
It lacts tricarboxylic acid (Kreb’s cycle)
What type of syphilis exhibits the ff and what is used to detect them: (1) condyloma lata, maculopapular rash, fever, headache, malaise, anorexia, lymphadenopathy (2) granulomas, neurosyphilis (tabes dorsalis, dementia paralytica), aortitis (3) local, non-tender ulcer (chancre) (4) saddle nose, mulberry molars, Hutchinson triad, saber shins, rhagades, Higoumenakis sign, Clutton’s joints, pulmonary hemorrhage
(1) Secondary syphilis; Rapid Plasma Reagin/Venereal Disease Research Laboratory for screening, Fluorescent Treponemal Antibody-Absorption for confirmation (2) Tertiary syphilis (3) Primary syphilis - dark-field microscopy (4) Congenital syphilis
The largest medically important bacteria is cultured on what medium?
BSK medium
Stage 1: erythema chronicum migrans Stage 2: myocarditis, meningitis, Bell’s palsy Stage 3: autoimmune migratory polyarthritis, acrodermatitis chronica atrophicans
Lyme disease (Borrelia burgdorferi)
Rapid antigenic changes due to programmed rearrangements of bacterial DNA encoding surface proteins
Relapsing fever (Borrelia recurrentis)
Leprospira interrogans is grown on _____ medium and only becomes positive after 2 weeks of incubation. However, the gold standard in detecting this bacteria is _____.
Ellinghausen-McCollough-Johnson-Harris (EMJH) medium or Fletcher’s medium Leptospire microscopic agglutination test (Lepto MAT)
Most severe form of Lepstospirosis: _____ Triad of: ___, ___, ___ Treated with _____
Weil’s syndrome Jaundice, bleeding, uremia Penicillin G
Phase of Leptospirosis that exhibits: (1) calf tenderness, conjunctival suffusion (2) aseptic meningitis, pulmonary involvement, hepatic necrosis, glomerulonephritis
(1) acute leptospiremic phase (2) immune leptospiruric phase
_________: perioral blistered lesions with honey-colored crust because there is an accumulation of neutrophils beneath the stratum corneum Erysipelas: _____________ _________: deeper infection involving subcutaneous/dermal tissues facilitated by hyaluronidase _________: rapidly progressive infection of deep subcutaneous tissues facilitated by ______.
1) Impetigo contagiosa 2) superficial infection extending into dermal lymphatics 3) Cellulitis 4) Necrotizing fasciitis 5) Exotoxin B
Most common bacterial cause of sore throat?
Streptococcus pyogenes
Tests for Scarlet Fever susceptibility
Dick Test
What are the components of the JONES criteria and what is it for?
Migratory Polyarthritis Erythema marginatum Chorea (Syndenham’s) Carditis (Pancarditis) Subcutaneous nodules P-E-C-C-S For acute rheumatic fever (Strep pyogenes)
Aerobic, non-spore forming, non-motile gram-positive rods Club or comma-shaped rods arranged in V or L shape Looks like Chinese characters Black colonies on tellurite plate Toxigenicity detected using _____ test
Corynebacterium diphteriae Modified Elek test
In Diphtheria Exotoxin inhibits protein synthesis by adding ADP-ribose to (1) _____. Exotoxin encoded by (2) _____ via transduction. (3) _____ result from death of mucosal epithelial cells.
(1) elongation factor-2 / EF-2 (2) beta-prophage (3) pseudomembranes
Beta-prophage encoded toxins
ABCDE shigA-like toxin Botulinum toxin Cholera toxin Diphtheria toxin Erythrogenic toxin
Anaerobic, gram-positive, spore-forming rods Tennis racket organism Habitat is soil Enters through traumatic breaks in the skin
Clostridium tetani
(1) What disease has the following signs and symptoms: strong muscle spasm, trismus, risus sardonicus, opisthotonos, respiratory failure? (2) What is the toxin that causes it? (3) This toxin releases glycine from what cells in the spinal cord?
(1) Tetanus (2) Tetanus toxin (3) Renshaw cells
If the patient is uncertain if he was given Tetanus vaccine or not, what should be given if: (1) contaminated wound? (2) clean, minor wound?
(1) Toxoid (TeANA) & TIG (ATS) (2) Toxoid (TeANA) only
(1) Clostridium botulinum is usually acquired from what source? (2) Botulinum toxin is a heat-labile or heat-stable toxin? And it blocks Acteylcholine release causing what type of paralysis? What is the pattern of paralysis?
(1) Bulging canned goods, honey, alkaline vegetables such as green peas, peppers and mushrooms, smoked fish (2) Heat-labile; flaccid paralysis; descending pattern
Bulbar signs of food-borne botulism
4 Ds Diplopia Dysphonia Dysarthria Dysphagia
Clostridium perfringens: (1) seen as _____ on blood agar (2) growth on _____ shows a nonmotile organism but with rapidly spreading growth on culture media (3) what toxigenic disease is seen as pain, edema and crepitation on affected limb, with hemolysis and jaundice? And what lecithinase cleaves the cell memebranes of C. perfringens leading to this spectrum of disease?
(1) double hemolysis (2) egg-yolk agar (3) gas gangrene; alpha toxin
(1) The suppression of normal flora, allowing the overgrowth of Clostridium difficile is facilitated by the following antibiotics? (2) Exotoxins A and B inhibit GTPases causes apoptosis and death of enterocytes, leading to _____.
(1) Clindamycin, 2nd & 3rd generation Cephalosporins, Ampicillin (2) Pseudomembranes
What causes: (1) Pseudomembranous colitis? (2) Pseudomembranous pharyngitis? (3) Pseudomembranous esophagitis?
(1) Clostridium difficile (2) Diphtheria (3) Candida
Listeria monocytogenes are aerobic, non-spore-forming gram positive rods, arranged in V or L shape, with (1) _____ motility. It exhibits paradoxical growth in cold temperature, called (2) _____. Pathogenesis is due to: (3) _____ - interacts with E-cadherin on the surface of cells. (4) _____ - escape from phagosomes. Actin rockets - propels the bacteria through the membrane of one human cell into another.
(1) tumbling motility (2) cold enhancement (3) internalin (4) listeriolysin
Spectrum of disease in Listeria monocytogenes Early-onset neonatal listeriosis (_____): transplacental transmission, late miscarriage, birth complicated by sepsis, multiorgan abscesses, disseminated granulomas _____: transmitted during childbirth, manifests as meningitis or meningoencephalitis _____: bacteremia, sepsis, meningitis in pregnant, elderly or immunocompromised
Granulomatosis infantiseptica Late-onset neonatal listeriosis Adult listeriosis
What is the causative agent of bulbous impetigo? Of impetigo contagiosa?
Bullous impetigo caused by S. aureus. Impetigo contagiosa caused by S. pyogenes.
Which Streptococcus spp are PYR-positive?
- Streptococcus pyogenes 2. Group D streptococcus
Streptococcus pyogenes is able to cause cellulitis because of this virulence factor which degrades components of subcutaneous/dermal tissues.
Hyaluronidase aka spreading factor
Streptococcus pyogenes releases this enzyme which has the end effect of reducing neutrophil chemotaxis.
C5a peptidase inactivates complement C5a. C5a is a major chemotactic agent of neutrophils.
S. pyogenes secretes exotoxins A and B, which are implicated in the pathogenesis of which two conditions.
Exotoxin A: streptococcal toxic shock syndrome. Exotoxin B: necrotizing fasciitis.
Which type of hypersensitivity reaction is exhibited by Rheumatic Fever? PSGN?
RF: Type II aka cytotoxic PSGN: Type III aka immune-complex mediated
What is the most common cause of neonatal sepsis worldwide? In the Philippines?
Group B streptococci worldwide; E. coli in the Philippines
What is the most common cause of endometritis?
Polymicrobial
How does one differentiate the Group D streptococci (E. faecalis, S. bovis)?
Culture in 6.5% NaCl. E. faecalis would grow; S. bovis would not.
Which etiologic agent in pneumonia causes… A. Currant-jelly sputum B. Rust-colored sputum C. Empyema, pneumatocele
A. Klebsiella pneumoniae (also most common etiologic agent in alcoholics) B. Streptococcus pneumoniae (also most common etiologic agent overall) C. Staphylococcus aureus (also most common cause of post viral pneumonia)
What is the most common cause of… A. Subacute endocarditis B. Acute endocarditis C. Endocarditis in patients with prosthetic valves
A. S. sanguis B. S. aureus C. S. epidermidis
What is the drug of choice for cutaneous anthrax?
Ciprofloxacin
Spore-forming Gram-(+) rod Aerobic Non motile Box-car shaped
Bacillus anthracis
Spore-forming Gram (+) rod Aerobic, motile Reheated fried rice
Bacillus cereus
Spore-forming Gram-(+) rod Anaerobic Tennis racket like
Clostridium tetani
Spore-forming Gram-(+) rod Anaerobic Bulging cans
Clostridium botulinum
Spore-forming Gram positive rod Anaerobic Lecithinase + Gas forming
Clostridium perfringens
Spore-forming Gram positive rod Anaerobic Pseudomembrane
Clostridium difficile
Non-spore forming Gram positive rod Aerobic, nonmotile Chinese characters
Corynebacterium diphtheriae
Non-spore forming Gram positive rod Aerobic, curved Tumbling motility
Listeria monocytogenes
3 etiologic agents associated with pulmonary hemorrhage
Bacillus anthracis (pulmonary anthrax) Leptospira interrogans (leptospirosis) Treponema pallidum (congenital syphilis)
What are the three antimicrobials in Thayer Martin agar?
Vancomycin (kills most G+ except Lactobacillus, Pediococcus) Colistin (kills most G- except Neisseria) Nystatin (kills most fungi)
Name three spirochetes.
BLT. Borrelia (Lyme disease) Leptospira (Leptospirosis) Treponema (Syphilis)
What antibiotic do you give as prophylaxis to close contacts expose to patients infected with Neisseria meningitidis?
Rifampin
Most common cause of septic arthritis: A. Overall B. Sexually active adults
A. S. aureus B. N. gonorrheae
Which phase in the natural history of pertussis is described? A. Highest yield for culture B. Repetitive cough with whoops C. Secondary complications (seizures, pneumonia, encephalopathy)
A. Catarrhal B. Paroxysmal C. Convalescent
Name facultative intercellular bacteria
Some Bugs May Live FacultativeLY. Salmonella Brucella Mycobacterium Listeria Francisella Legionella Yersinia
E. coli strains 1. Causes hemolytic uremic syndrome 2. Watery diarrhea in AIDS 3. Watery diarrhea in infants, developing countries 4. Traveller’s diarrhea
- EHEC (enterohemorrhagic) 2. EAEC (enteroadherent) 3. EPEC (enteropathogenic) 4. ETEC (enterotoxigenic)
Site of chronic typhoid infection
Gallbladder
Most common cause of septicemia in patients with sickle cell anemia
Salmonella cholerasuis
Chloramphenicol is a bacteriostatic drug except on the following pathogens in which it is cidal.
No Boyfriend Since HS Neisseria meningitidis Bacteroides fragility Streptococcus pneumoniae Haemophilus influenzae
Characteristic motility of: A. Vibrio spp B. Proteus C. Listeria D. Giardia
A. Shooting star B. Swarming C. Tumbling D. Falling leaf
Campylobacter jejuni infection is associated with these 2 diseases.
- Guillan-Barre 2. Reiter’s syndrome
Name cephalosporins with activity against Pseudomonas.
Ceftazidime Cefepime Cefoperazone
Most important virulence factor in Mycobacterium tuberculosis which prevents leukocyte migration
Cord factor
Most common extrapulmonary site of TB
Lymph nodes
Type 3 immune mediated Postpharyngitic or post-impetigo M protein incites immune complex deposition on the glomerular basement membrane What is the disease and the causative organism?
Glomerulonephritis Streptococcus pyogenes
1) What is the drug of choice for patients infected with S. pyogenes? 2) If a patient has a history of rheumatic fever what does he need to prevent recurrence?
1) Penicillin G 2) Long term antibiotic prophylaxis
Gram + cocci in chains Beta hemolytic Catalase negative Bacitracin resistant Hydrolyze hippurate CAMP test positive Lancefield group B Grown using LIM broth What is the organism?
Streptococcus Agalactiae (Group B Strep)
What is the most common cause of neonatal pneumonia, sepsis and meningitis? Predisposing factors include intrapartum fever PROM of >18H Complement deficiency
Streptococcus Agalactiae (Group B strep) Also, part of the predisposing factors is Vaginal Colonization
1) What is DOC for patients with S. agalactiae? 2) For those seriously infected? 3) as chemoprophylaxis for pregnant women given 4 hours prior to delivery?
1) Pen G 2) Pen G + Aminoglycoside 3) IV Penicillin or Ampicillin
Spectrum of disease: UTI in pregnancy Endometritis Neonatal pneumonia What is the organism?
Strep agalactiae
Gram + cocci in chains Catalase - Gamma colonies Lancefield group D Bile and optochin resistant Hydrolyzes esculin in Bile-Eschulin Agar Positive PYR test
Group D Streptococci
True or False 1) E. faecalis can grow in 6.5% NaCl? 2) S. bovis can grow in 6.5% NaCl?
1) True 2) False
Habitat is the colon Urethra and female genital tract can be colonized UTIs are due to catheters or other instrumentation Endocarditis in patients who underwent GIT surgery What is the offending organism and its treatment?
Group D streptococci Penicillin plus Gentamicin Vancomycin for Penicillin-resistant Linezolid for Vancomycin-resistant (Endocarditis sec to GIT surgery is usually caused by E. faecalis)
What kind of endocarditis is seen in patients with abdominal malignancy and what specific organism caused this?
Marantic endocarditis Streptococcus bovis (Group D Strep)
Gram (+) “lancet-shaped” cocci in pairs (diplococci) or short chains Alpha-hemolytic Catalase negative Bile and optochin sensitive Prominent polysaccharide capsule (+) Quellung reaction What is the Organism?
Streptococcus pneumoniae Quellung reaction is the swelling of the capsule
Found in the upper respiratory tract Capsule retards phagocytosis IgA protease for colonization C-substance reacts with CRP Can cause pneumonia, otitis media, bacterial meningitis, and septic shock What is the organism and its treatment?
Streptococcus pneumoniae Penicillin G Levofloxacin or Vancomycin combined with Ceftriaxone for penicillin resistance
Most common cause of CAP and what pattern will you see? How does one go about prevention of this organism?
Strep. pneumoniae Lobar pattern Polyvalent (23-type) polysaccharide vaccine Conjugated vaccine: pneumococcal polysaccharide couple with carrier protein (diphtheria toxoid)
Most common cause of otitis media, sinusitis and bacterial meningitis? What predisposes a patient infected by this organism to septic shock?
Streptococcus pneumoniae Splenectomy predisposes to sepsis (Skull fracture w/ spinal fluid leakage from nose predisposes to meningitis)
Gram + cocci in chains Alpha hemolytic Catalase negative Bile and optochin resistant Found in the oropharynx Usual culprit are dental procedures
E. viridans streptocci (S. mutans, S. sanguis, S. intermedius)
Its glycocalyx enhances adhesion to damaged heart valves They are protected from host defenses w/in vegetations With these info, what specific organism cause 1) dental caries 2) subacute bacterial endocarditis 3) brain abscess
(Organisms are under E. viridans strep) 1) S. mutans 2) S. sanguis (the most common cause of subacute and native valve endocarditis) 3) S. intermedius
How do you treat patients infected with E. viridans strep?
Pen G with or without an Aminoglycoside Vancomycin for penicillin-resistant Linezid for vancomycin-resistant
Aerobic Gram + box-car like rods Nonmotile Spore-forming Medusa head
Bacillus anthracis (Medusa head: dry “ground glass” surface and irregular edges with projections along lines of inoculation)
Treatment for anthrax?
Ciprofloxacin for cutaneous anthrax Ciproflixacin or Doxycycline with 1 or 2 additional antibiotics (Rifampin, Vancomycin, Penicillin, Imipenem, Clindamycin, Clarithromycin)
Causes Woolsorter’s disease Has poly-D-glutamate Can form edema toxin and lethal toxin What is the organism and what factors causes the toxins?
Bacillus anthracis Edema toxin: Edema Factor + Protective Antigen Lethal toxin: Lethal Factor + Protective Antigen Notes: Poly-D-glutamate: antiphagocytoc capsule Edema factor: Calmodulin-dependent adenylate cyclase Lethal factor: inhibits signal transduction in cell division Protective antigen: mediates entry of edema and lethal factors into the cell
These are all manifestations of one disease but differentiate the types 1) Malignant pustule, eschar and central necrosis with a 20% mortality rate 2) Massively enlarged mediastinal lymph nodes, Pulmo hemorrhage, Meningeal symptoms with a 100% mortality rate w/o immediate treatment 3) UGI ulceration, edema, sepsis with a mortality rate that approaches 100%
1) Cutaneous anthrax 2) Inhalational anthrax (there can also be a prolonged latent period of 2 mos before rapid deterioration) 3) Gastrointestinal anthrax
Recommended test in cases of dubious/equivocal PPD result (Jawetz)
IGR assay (interferon-gamma release assay)
Another use of BCG aside from TB prevention
Bladder CA
Drugs used in lepromatous leprosy
Dapsone Rifampin Clofazimine
Drugs used in tuberculoid leprosy
Dapsone Rifampin
Antibiotic of choice for Actinomycosis? Nocardia asteroides?
Actinomycosis: penicillin G Nocardia: TMP+SMX
Most common infectious cause of Stevens-Johnson syndrome
Mycoplasma pneumoniae
Causes of false positive VDRL results:
Viruses (EBV, Hepatitis) Drugs (marijuana) RF, RA Lupus, Leprosy
2 diseases in which Ixodes scapularis is the vector
Babesiosis Lyme disease (Borrelia burgdorferi)
This organism are aerobic, gram-positive spore forming rods that lives on grains and reheated fried rice. It has several toxins. Identify if the description describes a heat-labile or heat-stable toxin: (1) cholera-like enterotoxin causing ADP-ribosylation, increasing cAMP (2) short incubation period, consists primarily of nausea and vomiting (3) the diarrheal form has a long incubation period, with watery, nonbloody diarrhea (4) staphylococcal-like eneterotoxin that functions as a superantigen
(1) heat-labile (2) heat-stable (3) heat-labile (4) heat-stable
