Bacteriology Flashcards
Gram (+) cocci in clusters; Catalase (+); Coagulase (+)
Staphylococcus aureus
Gram (+) cocci in clusters; Catalase (+); Coagulase (-); Novobiocin sensitive
Staphylococcus epidermidis
Gram (+) cocci in clusters; Catalase (+); Coagulase (-); Novobiocin resistant
Staphylococcus saprophyticus
Beta hemolytic yellow or golden colonies on blood agar; Salt-tolerant on Mannitol Salt Agar; Normal flora of human nose and skin
Staphylococcus aureus
Gold color is due to the pigment
Staphyloxanthin
Alter immune response
Immunomodulators
Prevents Complement Activation
Protein A
Builds an insoluble fibrin capsule
Coagulase
Toxic to hematopoeitic cells
Hemolysins (cytotoxins)
Specific for white blood cells
PV Leukocidin
Detoxifies hydrogen peroxide
Catalase
Inactivates penicillin derivatives
Penicillinase
Hydrolyzes hyaluronic acid
Hyaluronidase
Dissolves fibrin clots
Fibrinolysin (Staphylokinase)
Spread in fat-containing areas of the body
Lipase
Causes epidermal separation
Exfoliatin
Superantigens causing food poisoning
Enterotoxins (heat-stable)
Superantigen leading to Toxic Shock Syndrome
Toxic Shock Syndrome Toxin (TSST-1)
Causes marked necrosis of the skin and hemolysis
Alpha Toxin
Skin and Soft Tissue Infections caused by S. aureus
Bullous impetigoFolliculitisFurunclesCarbunclesCellulitisHidradenitis suppurativaMastitisSurgical site infections
Most common cause of Acute Endocarditis
Staphylococcus aureus
Native valve involved in IV drug abusers
Tricuspid valve
Pneumonia caused by S. aureus
Nosocomial pneumoniaVAPNecrotizing pneumonia
Pneumonia by S. aureus: Complicated by
Empyema AbscessPneumatocoele
From hematogenous spread or local introduction at wound site
Osteomyelitis and Septic Arthritis
Sequestered focus of osteomyelitis arising in the metaphyseal area of a long bone
Brodie abscess
Acute onset (4hrs) of vomiting and diarrhea due to ingestion of preformed heat-stable enterotoxin; Usually from salad made with mayonnaise (potato or tuna); Common cause of food poisoning
Gastroenteritis by S. aureus
Exfoliatin cleaves Desmoglein in desmosomes; Separation of epidermis at Stratum Granulosum; Distinguish from TEN (Lyell Disease) where separation occurs at dermoepidermal junction
Scalded Skin Syndrome (Ritter Disease)
Due to TSST-1; Fever, hypotension, slouging of the filiform papillae; Strawberry tongue, desquamating rash & multi-organ involvement; Usually no site of pyogenic inflammation; Blood CS negative; Usual scenario: Tampon-using menstruating women or in patients with nasal packing for epistaxis
Toxic Shock Syndrome
Treatment: Methicillin-sensitive Staphylococcus aureus (MSSA)
NafcillinOxacillinDicloxacillin
Treatment: Methicillin-resistant Staphylococcus aureus (MRSA)
Drug of Choice: Vancomycin
Treatment: Vancomycin-resistant Staphylococcus aureus
Drug of Choice: Linezolid
Gram (+) cocci in clusters; Catalase (+); Coagulase (-); Novobiocin sensitive; Whitish, non-hemolytic colonies on Blood Agar; Normal flora of skin
Staphylococcus epidermidis
Most common cause of Prosthetic valve Endocarditis; Septic arthritis in prosthetic joints; Ventriculoperitoneal shunt infections
Staphylococcus epidermidis
Drug of choice for Staphylococcus epidermidis
Vancomycin
Gram (+) cocci in clusters; catalase (+); coagulase (-); Novobiocin resistant; Whitish, non-hemolytic colonies on Blood Agar
Staphylococcus saphrophyticus
2nd most common cause of UTIs in sexually active women
Staphylococcus saphrophyticus
Treatment for Staphylococcus saphrophyticus
TMP-SMX, Quinolones (Ciprofloxacin, Gatifloxacin)
Gram (+) cocci in chains; catalase (-); alpha hemolytic; bile optochin sensitive
Streptococcus pneumoniae
Gram (+) cocci in chains; catalase (-); alpha hemolytic; bile optochin resistant
Viridans streptococci
Gram (+) cocci in chains; catalase (-); beta hemolytic; bacitracin sensitive
Streptococcus pyogenes
Gram (+) cocci in chains; catalase (-); beta hemolytic; bacitracin resistant
Streptococcus agalactiae
Gram (+) cocci in chains; catalase (-); gamma hemolytic
Group D Streptococci
Measures hydrolysis of l-pyrrolidonyl-beta- naphthylamide and release of beta-naphthylamine, which in the presence of p-dimethylaminocinnamaldehyde forms a red compound.
PYR test
Gram (+) cocci in chains; Beta hemolytic; Catalase (-); Bacitracin sensitive; Lancefield group A; Positive PYR test; Normal flora of human throat and skin
Streptococcus pyogenes
Spreading factor
Hyaluronidase
Activates plasminogen
Streptokinase (fibrinolysin)
Degrades DNA in exudates or necrotic tissue
DNAse (Streptodornase)
Inactivates complement C5a
C5a peptidase
Produces Scarlet Fever
Erythrogenic toxin
Highly antigenic, causes AB formation; Oxygen-labile; Irreversibly inhibited by cholesterol in skin lipids
Streptolysin O
Oxygen-stable
Streptolysin S
Superantigen similar to TSST
Pyogenic exotoxin A
Protease that rapidly destroys tissue causing Necrotizing fasciitis
Exotoxin B
Titers to document antecedent pharyngitis
Anti-streptolysin O (ASO)
Titers to document antecedent skin infection
Anti-DNAse B
Antibodies decrease efficacy of streptokinase in managing MI
Anti-streptokinase
Perioral blistered lesions with honey-colored crust; Accumulation of neutrophils beneath stratum corneum; Complication: PSGN
Impetigo contagiosa
Superficial infection extending into dermal lymphatics; Painful
Erysipelas
Deeper infection involving subcutaneous or dermal tissues; Facilitated by hyaluronidase (spreading factor)
Cellulitis
Rapidly progressive infection of deep subcutaneous tissues; Facilitated by Exotoxin B
Necrotizing fasciitis
Most common bacterial cause of sore throat; Inflammation, exudate, fever, leukocytosis, and tender CLAD; Pyogenic complications: abscess, otitis, sinusitis, meningitis
Steptococcus pyogenes
Postpharyngitic; Due to erythrogenic toxin, seen in lysogenized strains; Fever, strawberry tongue, centrifugal rash (sandpaper-like), Pastia’s lines, desquamation
Scarlet Fever
Susceptibility test for Scarlet Fever
Dick Test
Clinically similar but milder than S. aureus TSS; Due to pyogenic exotoxin A; Recognizable site of pyogenic inflammation; Blood cultures are often positive
Streptococcal Toxic Shock Syndrome
Postpharyngitic; Cross reacting antibodies to M proteins and antigens of joint, heart and brain tissue
Acute Rheumatic Fever
JONES Criteria
P-E-C-C-SPolyarthritisErythema marginatumChorea (Sydenham’s)Carditis (Pancarditis)Subcutaneous nodules
Postpharyngitic or post-impetigo; M protein incites immune complex deposition on the glomerular basement membrane
Glomerulonephritis
Drug of choice for Streptococcus pyogenes
Penicillin G
Gram (+) cocci in chains; Beta hemolytic; Catalase (-); Bacitracin resistant; Hydrolyze hippurate; CAMP test positive; Lancefield group B; Grow using LIM broth; Normal flora of Vagina
Streptococcus agalactiae
Causative agent: Urinary Tract Infection in pregnant women
Streptococcus agalactiae
Most common cause of Neonatal pneumonia, sepsis, and meningitis
Streptococcus agalactiae
Most commonly polymicrobial Endometritis; Foul-smelling
Streptococcus agalactiae
Drug of choice for Streptococcus agalactiae
Penicillin G
Drug of choice for more serious S. Agalactiae infection
Penicillin G + Aminoglycoside
All pregnant women should be screened for GBS colonization at
35-37 weeks aog
Gram (+) cocci in chains; Catalase (-); Gamma (nonhemolytic) colonies; Lancefield group D; Bile and Optochin resistant; Hydrolyzes esculin in bile-esculin agar (BEA); positive PYR test; Normal flora of human colon
Group D Streptococci
Endocarditis in patients who underwent GIT surgery due to
Enterococcus faecalis
UTIs due to indwelling urinary catheters and urinary tract instrumentation; Biliary tract infections
Group D Streptococci
Marantic endocarditis in patients with abdominal malignancy due to
Streptococcus bovis
Associated Ca with Marantic Endocarditis
Pancreatic CaColorectal Ca
Treatment for Group D Streptococci
Penicillin plus Gentamicin
For Penicillin-resistance Group D Streptococci
Vancomycin
For Vancomycin-resistant Strains
Linezolid
Gram (+) “lancet-shaped” cocci in pairs (diplococci) or short chains; Alpha hemolytic; Catalase (-); Sensitive to bile and optochin; Prominent polysaccharide capsule; Quellung reaction (+); Normal flora of upper respiratory tract
Streptococcus pneumoniae
Optochin Sensitivity
OptochinViridans ResistantPneumonia Sensitive
Quellung Reaction
Capsular swelling
Encapsulated Bacteria
Streptococcus pneumoniaeKlebsiella pneumoniaeHaemophilus influenzaePseudomonas aeruginosaNeisseria meningitidisSalmonella typhiB group streptococci
Antiphagocytic factor
Capsule
For colonization
IgA protease
Reacts with CRP; Acute phase reactant
C-substance
Most common cause of Community Acquired Pneumonia (CAP); Sudden chills, fever, productive cough (rust-colored sputum), pleuritic chest pain; Lobar pattern
Streptococcus pneumoniae
Most common cause of Otitis media, Sinusitis, Bacterial Meningitis; Skull fracture with spinal fluid leakage from nose predisposes to meningitis
Streptococcus pneumoniae
Splenectomy predisposes to sepsis
Septic Shock
Congenital Absence of Spleen; Need to get meningococcal and pneumococcal vaccines
Ivemark Syndrome
Drug of choice for Streptococcus pneumoniae
Penicillin G
Gram (+) cocci in chains; Alpha hemolytic; Catalase (-); Resistant to bile and optochin; Normal flora of Oropharynx
Viridans Streptococci
Enhances adhesion to damaged heart valves
Glycocalyx
Protected from host defenses within
Vegetations
Found in Dental caries
Streptococcus mutans
Found in Subacute Bacterial Endocarditis (SBE); Most common cause of subacute and native valve endocarditis
Streptococcus sanguis
Found in brain abscesses
Streptococcus intermedius
Treatment for Viridans streptococci
Penicillin G with or without Aminoglycoside
Spore-forming, gram (+), rods; aerobic, nonmotile, box car-shaped
Bacillus anthracis
Spore-forming, gram (+), rods; aerobic, motile, reheated fried rice
Bacillus cereus
Spore-forming, gram (+), rods; anaerobic, tennis racket-like
Clostridium tetani
Spore-forming, gram (+), rods; anaerobic, bulging cans
Clostridium botulinum
Spore-forming, gram (+), rods; anaerobic, lecithinase, gas-forming
Clostridium perfringens
Spore-forming, gram (+), rods; anaerobic, pseudomembranes
Clostridium difficile
Non-spore-forming, gram (+), rods; aerobic, nonmotile, curved, chinese characters
Corynebacterium diphtheriae
Non-spore-forming, gram (+), rods; aerobic, curved, tumbling motility
Listeria monocytogenes
Aerobic, gram (+) box car-like rods; nonmotile; spore-forming; Medusa head morphology; Habitat: soil
Bacillus anthracis
Dry “ground glass” surface and irregular edges with projections along lines of inoculation
Medusa Head Morphology
Transmission by contact with infected animals or inhalation of spores from animal hair and wool
Woolsorter’s Disease
Calmodulin-dependent adenylate cyclase
Edema factor (EF)
Inhibits a signal transduction in cell division
Lethal factor (LF)
Mediates entry of the other two components into cell
Protective antigen (PA)
EF + PA =
Edema Toxin
LF + PA =
Lethal Toxin
True or False: EF, LF, PA are toxic individually.
False (nontoxic individually but form toxins when combined)
Direct epidermal contact with spores causes formation of malignant pustule with subsequent eschar and central necrosis
Cutaneous Anthrax
Inhaled spores from animals or from weaponized preparations (bioterrorism); Prolonged latent period before rapid deterioration; Massively enlarged mediastinal lymph nodes, pulmonary hemorrhage, meningeal symptoms
Inhalational Anthrax
Ingestion of live spores leads to UGI ulceration, edema, and sepsis (rapidly-progressive course)
Gastrointestinal Anthrax
DOC for Cutaneous Anthrax
Ciprofloxacin
DOC for Inhalational or Gastrointestinal Anthrax
Ciprofloxacin or Doxycycline with one or two additional antibiotics (Rifampicin, Vancomycin, Penicillin, Imipenem, Clindamycin, Clarithromycin)
Aerobic, gram (+), spore-forming rods, motile; Spores germinate when rice is kept warm for many hours
Bacillus cereus
Cholera-like enterotoxin causes ADP-ribosylation with increasing cAMP
Heat-labile Enterotoxin (Secretory Diarrhea)
Staphylococcal-like enterotoxin functions as superantigen
Heat-stable Enterotoxin
Short incubation period (4hrs); Consists primarily of nausea and vomiting, similar to Staphylococcal Food Poisoning
Emetic Form (heat-stable) Food Poisoning
Long incubation period (18hrs); Watery, non bloody diarrhea, resembling Clostridial gastroenteritis
Diarrheal Form (heat-labile) Food Poisoning
Occur after traumatic penetrating eye injuries of the eye with a soil-contaminated object; Complete loss of light perception within 48 hours of the injury
Ophthalmitis
Treatment for Emetic or Diarrheal Food Poisoning
Symptomatic treatment only
Treatment for Ophthalmitis
Vancomycin, Clindamycin, Ciprofloxacin or Gentamicin
Anaerobic, gram (+), spore-forming rods; Spore is at one end (terminal spore); tennis racket-like; Habitat: soil; Entry thru traumatic break in the skin
Clostridium tetani
Protease that cleaves proteins involved in the release of Glycine from Renshaw cells in spinal cord
Tetanus toxin (Tetanospasmin)
Spectrum of Disease: Tetanus
Strong muscle spasms Lockjaw (Trismus)Risus sardonicusOpisthotonosRespiratory Failure
Treatment and DOC for Tetanus
Debridement of primary woundDOC: Metronidazole (Pen G - Philippines)
Tetanus vaccination for clean, minor wound
Toxoid (TeANA) for uncertain or 3 doses who had last dose >10 years
Tetanus vaccination for contaminated wound
Toxoid (TeANA) & TIG (ATS) for uncertain or 3 doses who had last dose >5 years
Anaerobic, gram (+), spore-forming rods; Habitat: Soil; Transmitted in improperly preserved food
Clostridium botulinum
Heat-labile neurotoxin that blocks acetylcholine release causing flaccid paralysis (descending pattern)
Botulinum Toxin
Most common Botulinum Toxin in humans
Types A, B and E
Commercial preparation of Exotoxin A
Botox
Triad of Botulism
Symmetric descending flaccid paralysis (with prominent bulbar involvement)Absence of FeverIntact sensorium
When babies ingest spores found in household dust or honey; Due to absence of competitive bowel flora
Infant Botulism (Floppy Baby Syndrome)
Traumatic implantation and germination of spores at the wound site
Wound Botulism
Treatment for Botulism
Adequate ventilatory supportElimination of the organism from GITTrivalent Botulinum antitoxin (types A, B, E)
Anaerobic, gram (+), spore-forming rods; Nonmotile; Double hemolysis on Blood Agar; Growth on Egg-yolk Agar; Rapidly spreading growth on culture media; Habitat: soil and human colon
Clostridium perfringes
Caused by Alpha toxin which is a lecithinase that cleaves cellmembrane; Results from contamination of wound with soil or feces; Gas produced by anaerobic metabolism; Pain, edema & cellulitis with crepitation; Hemolysis and jaundice are common
Gas Gangrene (Myonecrosis)
Production of enterotoxin which acts as superantigen; 8-16 hour incubation period; Characterized by watery diarrhea with cramps and little vomiting; Resolves in 24 hours
C. perfringens Food Poisoning
Treatment for Gas Gangrene
Wound debridementPenicillin
Treatment for C. perfringens Food Poisoning
Supportive management
Anaerobic, gram (+), spore-forming rods; Exotoxin in stool detected by cytopathic effect (final phase by which viral cells infect cells) on cultured cells or ELISA; Carried in the colon; Transmitted by fecal-oral route
Clostridium difficile
Antibiotics that suppress normal flora in colon, allowing C. difficile to overgrow
Clindamycin2nd and 3rd Gen CephalosporinsAmpicillin
Inhibit GTPases, leading to apoptosis an death of enterocytes
Exotoxins A and B
Visual result of Exotoxins A and B
Pseudomembranes
This infection can precipitate flare-ups of ______?
Ulcerative colitis
Nonbloody diarrhea associated with pseudomembranes (yellow-white plaques) on the colonic mucosa
Pseudomembranous Colitis
Can occur in Pseudomembranous colitis
Toxic megacolon
What causes Pseudomembranous pharyngitis?
Corynebacterium diphtheriae
What causes Pseudomembranous esophagitis?
Candida albicans
Drug of Choice for Pseudomembranous colitis?
Metronidazole
Aerobic, non-spore-forming, non-motile, gram (+) rods; Club or comma-shaped rods arranged in V or L shape; Look like Chinese characters; Picket fence appearance; Metachromatic granules (Babes-Ernst granules or volutin granules); Black colonies on Tellurite plate; Habitat: Human throat
Corynebacterium diphtheriae
Toxigenicity Test for Corynebacterium diphtheriae
Elek Test
Exotoxin inhibits protein synthesis by adding ADP-ribose to ______
Elongation Factor-2 (EF-2)
Has ADP-ribosylating activity
Subunit A of EF
Binds the toxin to cell surface
Subunit B of EF
Exotoxin is encoded by ______?
Beta-prophage
Result from death of mucosal epithelial cells
Pseudomembranes
Prominent, thick, gray, pseudomembranes over tonsils and throat; Complications: airway obstruction, myocarditis, cranial nerve or muscle paralysis
Pseudomembranous pharyngitis
Treatment for Pseudomembranous pharyngitis?
AntitoxinPenicillin G
Aerobic, non-spore-forming, gram (+) rods; Arranged in V or L shape; Tumbling motility; Narrow zone of beta hemolysis; Paradoxical growth in cold temp (Cold Enhancement); Habitat: GI and female GUT; Transmitted across placenta or by contact and ingestion of unpasteurized milk products
Listeria monocytogenes
Interacts with E-cadherin on the surface of cells
Internalin
Escape from phagosomes
Listeriolysin
Propels the bacteria thru the membrane of one human cell and into another
Actin Rockets
Transplacental transmission; Characterized by late miscarriage or birth; Complicated by sepsis, multiorgan abscesses and Disseminated granulomas
Early-onset Neonatal Listeriosis (Granulomatosis Infantiseptica)
Transmitted during childbirth and manifests as meningitis or meningoencephalitis
Late-onset Neonatal Listeriosis
Bacteremia, sepsis, or meningitis in pregnant, elderly or immunocompromised individuals
Adult Listeriosis
Treatment for Listeriosis
Ampicillin with or without Gentamicin
Bacteria motility: Tumbling
Listeria monocytogenes
Bacteria motility: Swarming
Proteus mirabilis
Bacteria motility: Shooting-star
Vibrio cholerae
Bacteria motility: Falling leaf
Giardia lambia
Gram (-) diplococci, encapsulated, ferments maltose and glucose
Neisseria meningitidis
Gram (-) diplococci, insignificant capsule, ferments glucose only
Neisseria gonorrhoeae
Gram (-) “kidney-bean” diplococci; Large polysaccharide capsule; Oxidase (+) colonies on Chocolate Agar; Ferments maltose and glucose; Habitat: URT; Humans are the only natural hosts; High carriage rate in close quarters
Neisseria meningitidis
Complement deficiencies in the _____ predispose to illness; Cannot form membrane-attack complexes
Late-acting Complement Components (C5-C9)
Most common cause of Meningitis among aged 2-18 yrs; With headache, fever, stiff neck, and an increased level of PMNs in spinal fluid
Neisseria meningitidis
Dissemination of meningococci into the bloodstream; Multiorgan disease, consumptive coagulopathy, petechial or purpuric rash (purpura fulminans)
Meningococcemia
Most severe form of meningococcemia; High fever, shock, widespread purpura, DIC, thrombocytopenia and adrenal insufficiency; Bilateral hemorrhagic destruction of the adrenal glands
Waterhouse-Friderichsen Syndrome
Drug of Choice for Neisseria meningitidis
Penicillin G
Neisseria meningitidis Vaccine: Contains capsular polysaccharide of _____
Strains A, C, Y, and W-135
Chemoprophylaxis to close contacts
Rifampicin
Gram (-) “kidney-bean” diplococci; Insignificant capsule; oxidase (+) colonies on Thayer-Martin Medium; Ferment glucose only; Habitat: human genital tract; Transmitted by sexual contact
Neisseria gonorrhoeae
Purulent conjunctivitis in newborns
Ophthalmia neonatorum
Urethritis and epididymitis in men; Most common cause of urethritis (in men)
Gonococcal Urethritis
Most common cause of PID; Complications: sterility, ectopic pregnancy, chronic pelvic pain, dyspareunia
Neisseria gonorrhoeae
Perihepatitis with violin-string adhesions
Fitz-Hugh-Curtis Syndrome
Most common cause in sexually active adults; Arthritis, tenosynovitis, or pustules in the skin
Septic Arthritis
DOC for Neisseria gonorrhoeae
Ceftriaxone
DOC for N. Gonorrhoeae with co-infection with Chlamydia trachomatis
Ceftriaxone + Doxycycline
Cause culture-negative subacute bacterial endocarditis in patients with pre-existing heart disease
Eikenella corrodensKingella kingae
HACEK Organisms; Minor cause of Endocarditis
Haemophilus aphrophilusActinobacillus actinomycetemcomitansCardiobacterium hominisEikenella corrodensKingella kingae
Dog bite Infection
Pasteurella multocida
Human bite Infection
Eikenella corrodens
Gram (-) rods, enriched chocolate agar, polyribitol phosphate capsule
Haemophilus influenzae type B
Gram (-) rods, Regan Lowe agar or Bordet-gengou agar, whooping cough
Bordetella pertussis
Gram (-) rods, poorly gram staining, silver stain, charcoal yeast agar, airconditioning
Legionella pneumophila
Small, gram (-) coccobacillary rods; Requires Factor X (hemin) and V (NAD) for growth (chocolate agar); Satellite phenomenon around S. aureus colonies; Habitat: Upper Respiratory Tract
Haemophilus influenzae
95% of invasive disease of H. influenzae
Type B (Polyribitol phosphate)
Affects children from 6 months to 1 year; Decline in ____________
Maternal IgG and Immature immune system
Most common cause of Epiglottitis; Cherry red epiglottis with Thumb sign
Haemophilus influenzae
Etiology of Laryngotracheobronchitis
Parainfluenza virus
Radiologic sign of laryngotracheobronchitis
Steeple sign
Treatment for H. influenzae
Ceftriaxone
Treatment for Laryngotracheobronchitis
Racimic Epinephrine
Small, gram (-) rods; Culture on Bordet-Gengou agar or Regan-Lowe Charcoal Medium; Habitat: Upper Respiratory Tract
Bordetella pertussis
Mediates attachment
Filamentous hemagglutinin
Causes ADP-ribosylation and lymphocytosis
Pertussis Toxin
Inhibits phagocytic activity
False adenylate cyclase
Damages ciliated cells; Causes whooping
Tracheal cytotoxin
Paroxysmal pattern of hacking coughs, accompanied by production of copious amounts of mucus, that end with an inspiratory “whoop”
Pertussis or Tuspirina
Highest bacterial yield in Pertussis
Catarrhal
DOC for Pertussis
Erythromycin
Poorly gram (-) rods; Visualize with silver stain; Facultative intracellular bacteria; Culture on Charcoal yeast extract agar; Rapid urinary antigen test; Habitat: Environmental water sources
Legionella pneumophila
Facultative Intracellular Bacteria
SalmonellaBrucellaMycobacteriumListeriaFrancisellaLegionellaYersinia
Sole virulence factor of Legionella pneumophila
Endotoxin
3 Most common cause of Atypical Pneumonia
Mycoplasma pneumoniaeLegionella pneumophilaChlamydia pneumoniae
Pneumonia accompanied by confusion, nonbloody diarrhea, hyponatremia, proteinuria and hematuria
Atypical Pneumonia caused by Legionella pneumophila
Mild, flu-like illness, “Legion of Silver Pontiac”
Pontiac Fever
Drug of Choice for Legionella pneumophila
Azithromycin or Erythromycin
Gram (-) rods, lactose fermenter, green sheen
Escherichia coli
Gram (-) rods, lactose fermenter, urease (+), Extended spectrum Beta lactamase producer
Klebsiella pneumoniae
Gram (-) rods, comma-shaped, motile, oxidase (+), shooting star motility
Vibrio cholerae
Gram (-) rods, comma-shaped, microaerophilic, Skirrow’s agar (Campy’s Agar)
Campylobacter jejuni
Gram (-) rods, comma-shaped, urease (+), microaerophilic
Helicobacter pylori
Non-lactose-fermenting, gram (-) rods, motile, oxidase (-), H2S producer
Salmonella spp.
Non-lactose-fermenting, gram (-) rods, nonmotile, oxidase (-), H2S producer
Shigella spp.
Non-lactose-fermenting, gram (-) rods, swarming, oxidase (-), H2S producer, urease
Proteus mirabilis
Non-lactose-fermenting, gram (-) rods, oxidase (+), H2S non-producer, obligate aerobe
Pseudomonas aeruginosa
Facultative gram (-) rods, Lactose fermenting colonies on EMB or MacConkey’s Agar; Green sheen on EMB agar; Metallic sheen; TSI aar shows acid slant and acid butt with gas but no H2S; Habitat: Human colon
Escherichia coli
O antigen
Somatic antigen (outer membrane)
H antigen
Flagellar antigen
K antigen
Capsular antigen
Enterotoxins of E. coli that cause watery diarrhea
HSTHLT
Enterotoxins of E. coli that cause bloody diarrhea
Verotoxin (Shiga-like)
Enterobacteriaceae MESSY SPECK
MorganellaEscherichiaShigellaSalmonellaYersiniaSerratiaProteusEnterobacterCitrobacterKlebsiella
Most common cause of Community-Acquired UTI and hospital-acquired
E. coli
2nd most common cause of neonatal meningitis in the world (#1 in the Philippines)
E. coli
Causes of Neonatal meningitis
B group streptococci (S. agalactiae)Escherichia coliListeria monocytogenes
ETEC: Watery diarrhea (Traveller’s Diarrhea)
Enterotoxigenic E. coli
EPEC: Watery diarrhea of long duration, mostly in infants, often in developing countries
Enteropathogenic E. coli
EHEC: Bloody diarrhea, Hemorrhagic colitis, and Hemolytic Uremic Syndrome; Eating raw hamburger; E. coli O157:H7
Enterohemorrhagic E. coli
EIEC: Bloody diarrhea
Enteroinvasive E. coli
EAEC: Persistent watery diarrhea in children patients infected with HIV
Enteroadherent E. coli
Treatment for E. Coli
Ampicillin or Sulfonamides for UTI3rd Gen Cephalosporins for meningitis and sepsis
Facultative gram (-) rods, non-lactose-fermenting; Producing H2S; Cultured in Xylose-Lysine-Deoxycholate (XLD) medium; Habitat: human colon only
Salmonella spp.
Detects antibodies in patient’s serum
Widal Test
Invasion of the epithelial and subepithelial tissue of the small and large intestines; Infectious dose is high
Enterocolitis (S. Enteritidis/S. typhimurium)
Due to Vi capsular antigen; Organisms enter, multiply in Peyer’s patches and then spread to reticulo-endothelial system; Predilection for invasion of the gallbladder, which can result in establishment of the chronic carrier state
Typhoid Fever (S. typhi)
Bacteremia results in the seeding of many organs, with osteomyelitis, pneumonia, and meningitis as the most common sequelae; Commonly in patients with Sickle Cell Anemia or Cancer
Septicemia (S. choleraesuis)
Drug of Choice for Salmonella spp.
Ceftriaxone (Philippines: Amoxicillin Chloramphenicol, Cotrimoxazole)
DOC for Salmonella in Gallbladder
Ampicillin
Enteric Fever: Week 1 Culture Source
BloodBone marrow
Enteric Fever: Week 2 Culture Source
Urine
Enteric Fever: Week 3 Culture Source
Stool
Enteric Fever: Week 4 Culture Source
Bone marrow
Enteric Fever: Post Culture Source
BileStoolBone marrow
Non-lactose-fermenting, gram (-) rods; Produce no gas from the fermentation of glucose; Do not produce H2S; Nonmotile; Cultured XLD medium; Habitat: human colon only; Transmission: fecal-oral route
Shigella spp.
Shigella Transmission 4 Fs
FoodFingersFecesFlies
Invade the distal ileum and colon; Low infectious dose (highly infectious); Local inflammation accompanied by ulceration
Shigella
Most common cause of Bacillary Dysentery
Shigella Sonnei-Duval’s Bacillus
Most severe form of bacillary dysentery; Most common cause of epidemic dysentery (Bloody Diarrhea)
Shigella dysenteriae type 1 - Shiga Bacillus
Some produce an enterotoxin or verotoxin
Shiga toxin
Group A - Shigella dysenteriae
Shigella dysenteriae type1 - Shiga bacillusShigella dysenteriae type2 - Schmitz bacillus
Group B - Shigella flexneri
Flexner’s bacillus or Hiss and Russell’s bacillus
Group C - Shigella boydii
Newcastle Manchester bacillus
Group D - Shigella sonnei
Duval’s bacillus
Treatment for severe cases of Shigella Dysentery
Ciprofloxacin
Comma-shaped, gram (-) rods, motile, oxidase (+), cultured on Thiosulfate citrate bile salts sucrose (TCBS) agar; Shooting star motility; Habitat: human colon only
Vibrio spp.
Enterotoxin (choleragen) acts by
ADP ribosylation
Enhances attachment to the intestinal mucosa
Mucinase
Pandemics caused by
Vibrio cholerae O1 biotype El Tor (cholera El Tor)
Watery diarrhea in large volumes (rice-water stools); Washer women’s hand; Complications: cardiac and renal failure, non-gap acidosis, hypokalemia
Cholera (V. cholerae)
Generally self-limited with an explosive onset of watery diarrhea and nausea, vomiting, abdominal cramps, headache and low-grade fever
Gastroenteritis (V. parahemolyticus, V. vulnificus)
Associated with exposure to contaminated water
Wound infections (V. parahaemolyticus, V. vulnificus)
DOC for Cholera
Tetracycline or Azithromycin
Comma-shaped, gram (-) rods, microaerophilic, oxidase (+), catalase (+), grows well at 42C on Skirrows agar or Campy medium (with antibiotics); Habitat: human and animal feces
Campylobacter jejuni
Most common cause of bacterial gastroenteritis (from undercooked chicken); Possibly enterotoxin-mediated diarrhea; Invades mucosa of the colon but does not penetrate; Produces histologic damage to the mucosal surfaces of the jejunum; May mimic ulcerative colitis
Campylobacter jejuni
Antigenic cross-reactivity between oligosaccharides in bacterial capsule and glycosphingolipids on surface of neural tissues
Guillain-Barre Syndrome
Reactive arthritis; Triad of Urethritis, Uveitis and Arthritis
Reiter’s Syndrome
Treatment for Campylobacter jejuni for severe disease
Erythromycin
Curved, gram (-) rods, microaerophilic, urease (+); Habitat: human stomach
Helicobacter pylori
Urease (+) Bacteria
Proteus mirabilisKlebsiella pneumoniaeHelicobacter pyloriUreaplasma urealyticum
Damages goblet cells of the gastric mucosa; Production of large amounts of ammonia from urea by the organism’s urease; Ammonia also neutralizes stomach acid, allowing the organism to survive
Helicobacter pylori
Recurrent pain in the upper abdomen, frequently accompanied by bleeding into the gastrointestinal tract
Peptic Ulcer Disease
Diseases associated to Campylobacter jejuni
Gastric CarcinomaMALT lymphomas
Treatment for H. pylori infection
Clarithromycin or MetronidazoleAmoxicillin
Facultative gram (-) rods with large polysaccharide capsule (bacterial conjugation); Extended spectrum beta-lactamase (ESBL) activity in drug-resistant strains; Urease (+); Habitat: Upper Respiratory and GIT
Klebsiella pneumoniae
Pneumonia (necrotizing) thick, bloody sputum “currant-jelly sputum”, usually nosocomial; Most common cause in alcoholics
Klebsiella pneumoniae
Treatment for Klebsiella pneumoniae
Culture-guided treatment (Cephalosporins alone or with Aminoglycosides)
Facultative, gram (-) rods, non-lactose-fermenting, urease (+), swarming motility
Proteus mirabilis
Urease hydrolyzes the urea in urine to form ammonia; Raises pH producing alkaline urine; Encourage the formation of struvite stones; Composed of magnesium-ammonia-phosphate
Proteus mirabilis
UTI associated with nephrolithiasis; Staghorn calculi form on renal calyces
Complicated Urinary Tract Infection
Treatment for Proteus mirabilis
TMP-SMX or Ampicillin
Gram (-) rods, obligate aerobe, non-lactose-fermenting, oxidase (+), pyocyanin (blue-green pigment), sweet grape-like odor, grow on Cetrimide agar; Habitat: environmental water sources
Pseudomonas aeruginosa
Tissue necrosis and inactivates EF-2
Exotoxin A
Facilitates exotoxin transfer
Type III secretion system
Damages the cilia and mucosal cells
Pyocyanin
From hemoglobin breakdown
Verdoglobin
Cause burn wound infections, hot tub folliculitis, skin graft-loss, green nail syndrome, puncture wound osteomyelitis, pubic osteomyelitis in IV drug abusers
Pseudomonas aeruginosa
Most common cause of Otitis externa, Malignant otitis externa in diabetics, Chronic suppurative otitis media
Pseudomonas aeruginosa
Ventilator-acquired pneumonia; High risk CAP; Typhlitis; Shanghai fever; ecthyma gangrenosum; februle neutropenia
Pseudomonas aeruginosa
3rd most common cause of Nosocomial UTIs
Pseudomonas aeruginosa
Treatment for Pseudomonas aeruginosa
Combination of active antibiotics (antipseudomonal penicillins, 3rd & 4th Gen Cephalosporins, Monobactam, Carbapenems, Fluroquinolones)
Anaerobic, gram (-) rods, predominant anaerobe of human colon, spreads to blood or peritoneum during bowel trauma, perforation or surgery
Bacteriodes fragilis
Infections commonly due to combinations if bacteria in synergistic pathogenicity; LPS with low endotoxic activity; Capsule; Foul smelling discharge; short-chain fatty acid products
Bacteriodes fragilis
DOC for Bacteriodes fragilis
Metronidazole
Small, gram (-) rods, without a capsule; From contaminated dairy or direct contact; Undulating Fever
Brucellosis
DOC for Brucellosis
Doxycycline plus Rifampin
Small, gram (-) rods; Reservoir: rabbits, deer, rodents; Transmission: ticks, aerosols, contact, ingestion; Tularemia
Francisella tularensis
Treatment for Francisella tularensis
Streptomycin or Gentamicin
Most virulent bacteria; small, gram (-) rods, with bipolar (safety pin) staining; Reservoir: wild rodents; Transmission: flea bite or inhalation; PE: buboes, cutaneous hemorrhage
Yersinia pestis
Treatment for Bubonic, Pneumonic, and Septicemic Plague
StreptomycinTetracycline
Short, encapsulated, gram (-) rods that exhibits bipolar staining; Buttery colonies with musty odor due to indole production; Reservoir: cats, dogs; Transmission: animal bite
Pasteurella multocida
Treatment for Pasteurella multocida
Penicillin G
Zoonoses
Brucella abortusFrancisella tularensisYersinia pestisPasteurella multocida
Aerobic, acid-fast rods; High lipid content; Produces catalase and niacin; Slow-growing on Lowenstein-Jensen medium; Habitat: human lungs; Transmission via respiratory droplets
Mycobacterium tuberculosis
Exported repetitive protein that prevents phagosome-lysosomal fusion
Sulfatides
Most important virulence factor that prevents leukocyte migration
Cord Factor
Elicits delayed hypersensitivity
Tuberculin surface protein
Central area of Langhan’s giant cells surrounded by a zone of epithelioid cells
Granulomatous Lesions
Granuloma surrounded by fibrous tissue that has undergone central caseation
Tubercle
Usually in middle or lower lobes; Subpleural granuloma
Ghon’s Focus in Primary Complex
Subpleural granuloma + associated lymph node =
Ghon’s complex
Radiologically detectable calcification
Ranke’s complex
Usually in apices; Cicatricial changes, subpleural blebs, cavitation, fibrosis, nodules
Simon’s Focus in Reactivation Tuberculosis
Secondary colonization with A. fumigatus (fungus ball)
Aspergilloma
Purified Protein Derivative Skin Test
> 5mm - HIV+, AIDS, old TB, immunosuppressed>10mm - high-risk population>15mm - low-risk population (In Phil: 8mm accepted)
TB Lymphadenitis
Scrofula
Spondylitis
Pott’s Disease
2 or 3 smear positive
Smear Positive TB
If at least 1 smear positive after another collection
Smear Positive TB
If all smear negative and consistent with active TB chest x-ray
Smear Positive TB
Treatment for Category 1
2 months HRZE and 4 months HR
Treatment for Category 2
2 months HRZES & 1 month HRZE5 months HRE
Treatment for Category 3
2 months HRZE4 months HR
Can you name other uses of BCG vaccine aside from TB prevention?
For management of Intravesical Bladder Cancer
Cause pulmonary disease in immunocompromised hosts (AIDS patients with CD4
Mycobacterium Avium-Intracellulare Complex
DOC of Mycobacterium Avium-Intracellulare Complex
Azithromycin
Aerobic, Acid-fast rods; Can’t be cultured in vitro; Reservoir: humans and armadillos; Transmission: prolonged exposure to nasal secretions of patients with the lepromatous form
Mycobacterium leprae
Tuberculoid Leprosy: Number of lesions
One or few
Tuberculoid Leprosy: Tissue destruction
Little
Tuberculoid Leprosy: Number of acid-fast bacilli
Few
Tuberculoid Leprosy: Likelihood of transmitting leprosy
Low
Tuberculoid Leprosy: Cell mediated response to M. leprae
Present
Tuberculoid Leprosy: Lepromin skin test
Positive
Lepromatous Leprosy: Number of lesions
Many lesions
Lepromatous Leprosy: Tissue destruction
Marked
Lepromatous Leprosy: Number of acid-fast bacilli
Many
Lepromatous Leprosy: Likelihood of transmitting leprosy
High
Lepromatous Leprosy: Cell-mediated response to M. leprae
Reduced or Absent
Lepromatous Leprosy: Lepromin skin test
Negative
Hypopigmented plaques, thickened superficial nerves and significant anesthesia
Tuberculoid Leprosy
Leonine facies; Erythema nodosum leprosum which signals acute flare-ups of disease and are tender red nodules or humps on both shins
Lepromatous Leprosy
Treatment for Tuberculoid Leprosy
Dapsone & Rifampin
Treatment for Lepromatous Leprosy
Dapsone, Rifampin, and Clofazimine
Treatment for Erythema nodosum leprosum
Thalidomide
Associated with congenital malformation: Focomelia (flipper-like limbs)
Thalidomide
Anaerobe (normal oral flora); Setting: local trauma (broken jaw or dental extraction); PE: hard, nontender swelling with sinus tracts draining
Actinomyces israelii
Aerobic, filamentous, gram (+) rods with aerial hyphae; weakly acid-fast (Fite-Faraco Stain); Transmission: inhalation of particles from soil; Manifests as mycetomas and lung and brain abscesses (orange colonies)
Nocardia asteroides
Treatment for Nocardiosis
TMP-SMX + drainage
Smallest free-living organisms; Not seen on gram stain; No cell wall; Only bacteria with cholesterol in cell membrane; Cultured in Eaton’s medium; Habitat: human respiratory tract
Mycoplasma pneumoniae
Attachment, inhibition of ciliary motion and necrosis; Toll-like receptor 2 protein
P1 adhesin
Contributes to the damage to the respiratory tract cells
Hydrogen peroxide
Most common type of atypical pneumonia or walking pneumonia
Mycoplasma pneumoniae
Most common infectious cause for Steven-Johnson Syndrome
Mycoplasma pneumoniae
DOC for Mycoplasma pneumoniae
Erythromycin or Azithromycin
Coiled spirochete; Not seen on gram stain because too thin; Cannot be cultured in vitro; Microaerophilic; Habitat: Human Genital Tract
Treponema pallidum
Within hours, enters lymphatics and multiplies; Local, nontender ulcer (chancre) usually forms in 2-10 weeks
Primary Syphilis
Condyloma lata, maculopapular rash, fever, headache, malaise, anorexia, lymphadenopathy; Occurs after 1 to 3 months
Secondary Syphilis
Many years after inoculation; Clinical spectrum: granulomas (gummas), neurosyphilis
Tertiary Syphilis
Neurosyphilis: Prostitute’s pupil
Argyll-Robertson Pupil
Snuffles/saddle nose; mulberry molars; Hutchinson triad; saber shins; rhagades; clutton’s joints; pulmonary hemorrhage
Congenital Syphilis
Unilateral enlargement of the sternoclavicular portion of the clavicle
Higoumenakis sign
Most important diagnostic test for Primary Syphilis
Dark Field Microscopy
For Screening of Syphilis
Rapid Plasma ReaginVenereal Disease Research Laboratory (RPR/VDRL)
For confirmatory test for Syphilis
Fluorescent Treponemal Antibody-Absorption (FTA-ABS)
False Positive VDRL Results
VirusesDrugsRheumatic Fever, Rheumatoid arthritisLupus, Leprosy
Treatment for Syphilis
Benzathine Penicillin G
Influenza-like symptoms few hours after receiving Penicillin, due to Lysis of Treponemes
Jarisch-Herxheimer Reaction
Weakly staining, gram (-) spirochetes; Largest medically-important bacteria; Stain well with aniline dyes (Giemsa or Wright Stain); Cultured on BSK medium; From bite of deer ticks (Ixodes scapularis)
Borrelia burgdorferi
Stage 1 of Lyme Disease
Erythema Chronicum Migrans
Stage 2 of Lyme Disease
Myocarditis (AV block), meningitis, Bell’s palsy
Stage 3 of Lyme Disease
Autoimmune migratory polyartjritis (onion skin lesions), acrodermatitis chronica atrophicans
Lyme Disease
Bell’s PalsyArthritisCardiac blockErythema chronicum migrans
DOC for Borrelia burgdorferi
Doxycycline
Rapid antigenic changes due to programmed rearrangements of bacterial DNA encoding surface proteins; Transmitted: human body louse (Pediculus humanus)
Relapsing Fever (Borrelia recurrentis)
Thin, coiled spirochetes, hook at one or both pointed ends (Shepherd’s Crook); Obligate aerobe, grown on Ellinghausen-McCullough-Johnson-Harris (EMJH) medium or Fletcher’s medium; Habitat: wild and domestic animals
Leptospira interrogans
Hallmark lesion of Leptospira interrogans
Vasculitis
Gold Standard Diagnostic For Leptospira interrogans
Leptospire microscopic agglutination test (lepto MAT)
Fever, chills, intense headache, calf tenderness, conjunctival suffusion
Acute Leptospiremic Phase
Aseptic meningitis, pulmonary involvement, hepatic necrosis, glomerulonephritis, snow-flake lesions in chest x-ray, CSF pleocytosis
Immune Leptospiruric Phase
Most severe form of Leptospirosis; Triad: Jaundice, Bleeding, Uremia; Orange cast skin; Most common cause of death is respiratory failure due to massive pulmonary hemorrhage
Weil Syndrome
Treatment for Leptospira interrogans
Penicillin G
Obligate intracellular bacteria; Energy parasites that use host ATP; Cell wall lacks muramic acid; Grown in cycloheximide culture; Cytoplasmic inclusions in Giemsa
Chlamydia trachomatis
Inactive, extracellular; Enters cells by endocytosis
Elemental Body
Metabolically active, intracellular; Seen microscopically
Reticulate Body
Most common STD overall
Chlamydia
Chronic keratoconjunctivitis progressing to scarring and blindness
Trachoma
Most common cause of Infectious Blindness
Chlamydia trachomatis types A-C
Round to oval cytoplasmic inclusion bodies near the nuclei of conjunctival epithelial cells in trachoma
Halberstadter-Prowazek Inclusions
Trachoma A, B, C
AfricaBlindnessChronic infection
Striking tachypnea, characteristic paroxysmal cough (Staccato cough), absence of fever, eosinophilia
Chlamydia trachomatis types D-K
Papule or vesicular which ulcerates and leads to suppurative inguinal lymphadenitis (buboes)
Chlamydia trachomatis types L1-L3
Intradermal injection of antigen of C. trachomatis
Positive Frei Test
Initiate lesion development or cause exacerbation of lesions; higher titers of Anti-C. pneumoniae antibodies
Chlamydia pneumoniae (Atypical pneumonia)
Sudden onset pneumonia with malaise, fever, anorexia, sore throat, photophobia, and severe headache
Psittacosis or Bird Fancier’s Disease (Chlamydia psittaci)
Treatment of STD (Chlamydia psittaci)
Azithromycin
Treatment of Conjunctivitis (Chlamydia psittaci)
Erythromycin
Treatment of LGV
Doxycycline
Treatment of Psittacosis
Azithromycin
DOC for all Rickettsial infections
Doxycycline
Disease caused by Rickettsia rickettsii
Rocky mountain spotted fever
Disease caused by Rickettsia akari
Rickettsial pox
Disease caused by Rickettsia prowazekii
Epidemic typhus
Disease caused by Rickettsia typhi
Endemic typhus
Disease caused by Orientia tsutsugamushi
Scrub typhus
Disease caused by Coxiella burnetti
Q fever
Disease caused by Ehrlichia chaffeensis
Ehrlichiosis
Vector of Rickettsia rickettsii
Tick
Vector of Rickettsia akari
Mites (chiggers)
Vector of Rickettsia prowazekii
Body louse
Vector of Rickettsia typhi
Rat flea
Vector of Orientia tsutsugamushi
Mites (chiggers)
Vector of Coxiella burnetti
None
Vector of Ehrlichia chaffeensis
Ticks
Incubation period of Rickettsia rickettsii
7
Incubation period of Rickettsia akari
9-14
Incubation period of Rickettsia prowazekii
8
Incubation period of Rickettsia typhi
7-14
Incubation period of Orientia tsutsugamushi
10-12
Incubation period of Coxiella burnetti
4-90
Incubation period of Ehrlichia chaffeensis
7-21
Rickettsial infection with eschar
Rickettsial pox
Gram (-) rod, Normal oral flora of cats, “cat-scratch fever”, bacillary angiomatosis, transmission: cat bite or scratch
Cat Scratch Disease
Dog reservoir, Transmission: dog tick (Dermacentor) bite, forms morulae in cytoplasm of monocytes
Ehrlichiosis (Ehrlichia chaffeensis)
Facultative gram-variable rod; Clue cells present; Positive whiff test (fishy odor); Malodorous vaginal discharge
Bacterial vaginosis (Gardnerella vaginalis)
Small gram (-) rod, culture on chocolate agar with heme (factor X); painful genital ulcer
Chancroid (Haemophilus ducreyi)
Gram (-) rods, reservoir: domestic animals, transmission: oro-fecal route
Mesenteric Adenitis or Pseudoappendicitis (Yersinia enterocolitica)
Encapsulated, pleomorphic gram (-) bacillus, bipolar densities (Donovan bodies) look like closed safety pins, small painless papule ulcerates to form beefy red ulcer with velvety surface, pseudobuboe formation
Granuloma inguinale (Donovanosis) Klebsiella granulomatis
Treatment for Klebsiella granulomatis or Donovanosis
Azithromycin
