Micro Flashcards
Corynebacterium diphtheria?
G+ve Bacilli, aerobic
Appearance:- club shaped metachromatic ( red and blue) granules on Loffler media
Transmission:- resp droplets
Virulence:- Exotoxin Beta propophage which inhibits protein synthesis via ADP ribolysation of EF2 causing necrosis
Causes:pseudomembranous pharyngitis, LN, myocarditis
Mgx:- diphtheria antitoxin, erythromycin +/- penicillin
Listeria monocytogenes?
G+ve bacilli, anaerobic, intracellular
Transmission :- unpasterurised milk, vaginal transmission, ttansplacental, deli meats
Appearance:- rocket (red) tails, motile
Exotoxin:- listeriolycin causes pores in phagosomes allowing escape
Causes:- amnionitis, spontaneous abortion, meningitis in immunocompromised, ltd gastroenteritis in health
Mgx:- ampicillin
Nocardia?
G+ve branching filament
Catalase +ve
Appears:- resembles fungi
Transmission:- found in soil
Causes:- pulmonary infection in immunocompromised
Mgx:- sulfonamides
Actinomyces?
G+ve branching filaments
Catalase -ve
Appears:- looks like fungi
Transmission:- normal oral, reproductive flora
Causes:- dental abscess, PID with IUD
Mgx :- penicillin
Mycobacteria?
Acid fast rods on Ziehl Nielsen (pink long rods)
Transmission:-1o close contact with pt infected with TB, or reactivation
Virulence:- cord factor ( serpentine cord) activates macrophages promoting granulation and release of TNF alpha
Causes :- 1o TB , 2o TB milliary TB
Mgx:- drug resistant —> use multi drug regimen
Mycobacterium leprae?
G+ve rods prefer cool temps (skin peripheries glove and stocking)
Transmission: armadillos
Causes:- lepromatous leprosy:- high TH2, low cell mediated immunity, lion face v contagious
Tuberculoid leprosy:- high TH1, high cell medicated immunity, low bacterial loaded, hypopigmented hairless skin plaques
Mgx:- lepromatous :- clofazimine
Tuberculoid:- rifampin + dapsone
Neisseria meningitides?
G-ve diplococci
Can breakdown maltose and glucose
Virulence:- Lipoolygosaccharide capsule, IgA protease
Transmission:- resp droplets
Causes :- menigiococcaemia, petechia haemorrhage and gangrene of toes, Friedrichs Waterhouse syndrome ( haemorrhage cause adrenal insufficiency
Mgx:- Ceftriaxone/ penicillin G
Prophylaxis:- rifampin
neiserria gonnorrhoea ?
G-ve diplococci
Brake down glucose
No polysaccharide capsule
Transmission:- STI, perinatally
Causes:- gonorrhoea, neonatal conjunctivitis, septic arthritis
Mgx:- ceftriaxone single IM does
Prophylaxis:- safe sex, erythromycin ointment babies
Haemophillus influenzae?
G-ve coco bacillus
Chocolate agar
Virulence:- phosphoribosylribotol phosphate capsule , produces IgA protease Transmission
Transmission:- resp droplets Exotoxin Beta
Causes:- epiglottis in children, MOPS
Mgx:- amoxicillin +/- clavulanate
Prophylaxis:- rifampin close contacts
Vaccine :- contains type b capsular polysaccahride polyribosylriobotl phosphate
Bortadella pertussis?
G-ve aerobic coco bacillus
Virulence factor:- pertussis toxin ( disables Gi protein 2nd messenger —> inc CAMP) + tracheal cytotoxic
Causes:- flu like illness, barking cough post tussive emesis, chronic cough slow recovery
Mgx:- macrolides
Vaccine:- DTAP
leigonella pneumophilia?
G-ve rod ( poor gram staining)
Stains with silver
Grows on charcoal yeast extract with silver and cysteine
Transmission:- contaminated A/c
Causes:- legionnaire’s disease :- GI symptoms with symptoms of pneumonia , hyponatraemia
Diagnosis :- urine Ag
Mgx:- macrolide
Pseudomonas aeruginosa?
G-ve bacilli, aerobic, non lactose fermenting, oxidase +ve , catalase+ve , increased virulence in acidic environment
Appears:- green pigment
Virulence:- mucopolysaccharide capsule, Phospholipase C , Endotoxin, Exotoxin A
Causes:- pneumonia, UTI, ecthyma gangrenoum , sepsis osteomyelitis , folliculitis
@risk groups:- diabetics, impatient, drug users
Salmonella typhi?
G-ve bacilli/rods non lactose fermenting, oxidase -ve, produces H2S
Virulence:- invasion of M cells on Meyer patches, flagella can swim Vi capsule (tyVi) endotoxin
Transmission:- haematogenous
Causes:- constipation followed by non bloody diarrhoea , typhoid fever , monocyte infiltration
Vaccine :- oral vaccine—-> attenuated salmonella typhi, IM vaccine Vi capsular saccharide
Carrier:- in gallbladder
Shigella:-
G-ve rod non lactose fermenting, oxidase -ve does not produce H2S,
Virulence:- shiga toxin, invasion of M cells on Peyers patch infection dose low
Transmission :- cell to cell
Causes :- bloody diarrhoea neutrophil infiltration
Pseudomonas aeruginosa?
G-ve lactose -ve oxidase +ve rod
Causes UTI in pts with indwelling urinary catheters
Bortadella pertussis?
G-ve cocobacillus
Affects unvaccinated
Non invasive secretes exotoxins that damage ciliated resp epithelium.
Symptoms mild cough, rhinorrhoea, barking cough, posttussive emesis
Histoplasma capsulatum?
Dimorphic fungus, small ovoid year
Encapsulated in macrophage and spreads thoughout the lymphatic and reticuloendothelial system
Causes:- ltd pulmonary infection in healthy
In immunocompromised hepatospleenomegaly, lymphadenopathy and pancytopenia
Ulcerated tongue characteristic
HPV associations?
HPV 16 and 18 assoc with Cx Ca
Penile and anal Ca
Presence of HIV increases risk
Hepatitis D virus
RNA virus - circular single strand
It’s replication defective as it needs to be coated by HBsAg to be able to penetrate the hepatocyte
Infection is either co-infection with Hep B or superinfection of chronic Hep B carrier
Quick onset food poisoning
Staph aureus ( commonest cause) also B cereus
Food:- eggs, dairy and mayo based salads
Mediated by :- preformed enterotoxin ingested
Symptoms :- vomiting
Staph aureus virulence factor
Protein A which bind to the Fc portion of IgG inhibiting complement activation and phagocytosis
Giardia lamblia
Symptoms:- (think lactose intolerance) bloating, flatulence, foul smelling non bloody fatty diarrhoea
Transmission :- cysts in water
Diagnosis:-, multinucleated trophozite, cysts in stool, PCR Ag detection
Treatment:-tinidazole, metronidazole
Entamoeba histolytica
Causes ameobiasis
Bloody diarrhoea, RUQ pain, liver abscess with anchovy paste exudate
Transmission:- cysts in water
Diagnosis: PCR, Ag detection, trophozite with RBC in its cytoplasm, cysts with <4 nuclei in stool
Mgx:- metronidazole , parmomycin for carriers
Cryptosporidium
Severe diarrhoea in AIDS
Transmission:- oocysts in water
Diagnosis:- oocysts in acid fast stain, Ag, PCR
Toxoplasma Gondii
Causes:- immunocompromised —> mononucleosis like symptoms
AIDS —> Multiple brain abscess ring enhancing leisons on MRI
Congenial toxoplasmosis——-> triad hydrocephalus, intracranial calcification and chorioretinitis
Transmission:- cyst in meat, oocysts in cat faeces cross the placenta
Diagnosis:- serology, biopsy (tachzoite)
Mgx:- sulfadizine +/- pyrmethamine
Naegleria fowleri
Transmission:- warm fresh water - amoebas enter CNS through olfactory nerve via cribiform plate
Causes:- rapidly fatal meningioencephalitis
Diagnosis:- amoeba in CSF
Mgx:- amphotericin B may help
Trypanosoma Brucei
Transmission:- Tsetse fly bite
Causes:- African sleeping sickness—-> lymphadenopathy, recurring fever, somnolence, coma
Diagnosis:- trypomastigote in bld smear
Mgx:- suramin for blood, melasoprol for CNS penetration
Plasmodium
P malariae:- 72 hr fever cycle —> trophozite ring in RBC
P ovale/vivax:- 48 hr fever cycle —-> dormant (hypnozoite form) in liver —-> trophozites with stippling in RBC cytoplasmic —> give primaquine to target hypnozoites
P falciparum:- variable fever cycle—-> parasitized RBC can occlude brain (cerebral malaria) liver, lungs —> trophozite with head phone ring , crescent gametocytes
Diagnosis:- peripheral bld smear
Mgx:- chloroquine if resistant mefloquine / doxycycline
Babesiosis
Transmission:- tick
Causes:- fever, haemolytic Anaemia, in NE and NCentral USA, asplenia increase risk of severe disease
Diagnosis:- ring form or Maltese cross on bld smear
Mgx:- atovaquone + azithromycin
Trypanosoma cruzi
Transmission:- triatomine (kissing insect) bites around mouth and eye -faecal transmission into bite. In S America
Causes: - Chagas’ disease —: dilated cardiomyopathy, megacolon, megaoesophagus, perioribital swelling early sign
Diagnosis:- trypomasgtigote in bld smear
Mgx:- Benznidalzole
Leishmania
Transmission: - sandfly
Causes:- cutaneous :- ulcers
Visceral:- fever, hepatospleenomegally, pancytopenia
Diagnosis:- macrophages containing amastigotes
Mgx:- amphotericn B
Trichomonas vaginalis
Transmission:- sexual
Causes:- vaginitis - foul smelling greenish discharge itching and burning, punctuate Cx haemorrhage ( strawberry Cx)
Diagnosis:- motile trophozite on wet mount
Mgx:- metronidazole for pt and partner
Enterobius vermicularis
Transmission:- faeco-oral
Causes:- anal pruritis esp at night children 5-10
Diagnosis:- eggs visualized by tape test
Mgx:- bendazoles
Ascaris lumbricoides
Transmission:- faeco-oral
Causes:- biliary obstruction, ileocaecal valve obstruction, intestinal perforation —> migrate to alveoli —> loffler syndrome ( pulmonary eosinophilia)
Diagnosis:- knobby oval eggs in faeces
Mgx:- bendazole
Trichinella Spiralis
Transmission:- undercooked meat
Causes:- myositis , trichinosis:- fever, myalgia, vomiting periorbital oedema
Mgx :- bendazole
Trichuris Trichuria
Transmission:- faeco-oral
Causes:- asymptomatic, loose stools ,rectal prolapse children
Mgx:- bendazole
Toxacara Canis
Transmission:- faeco-oral
Causes:- visceral larva migrans —-> migrates into bld, carditis, seizure , inflammation of liver and eye ( visual impairment )
Mgx:- bendazole
Strongyloides stercoralis
Thread worm
Transmission:- larvae in soil penetrate skin
Causes:- Gi symptoms ( duodenitis) pulmonary symptoms ( dry cough, haemoptysis) and pruritis
Diagnosis:- rhabiditiform larvae in faeces
Carrier:- Yes
Mgx:- ivermectin
Ancylostoma and Necator
Hookworms
Transmision:- walking barefoot - larvae penetrate skin
Causes:- microcytic anaemia from worm sucking blood from intestinal wall
Cutnaneaous larva migrans:- pruritic serpiginous rash
Mgx:- bendazole
Onchocerca volvulus
Transmission:- black fly
Causes:- river blindness , black nodules
Mgx:- ivermectin
Loa Loa
Transmission:- deer, horse, mango fly
Causes:- worm in the conjuctiva, swelling in skin
Mgx:- diethycarbamezine
Wuchereia Bancrofti
Transmission:- female mosquito
Causes:- lymphatic filariasis ( elephantiasis) 9/12- 12/12 after bite —> worm invade KN causing lymphaedema
Mgx:- diethycarbamezine
Taenia Solium
Intestinal tape worm / pork tapeworm
Transmission: - ingestion of eggs in contaminated food
Causes:- seizures, neurocycticercosis —> CNS leisons, round cysts or calcified nodules on imaging ( occurs when humans eat T solium eggs in contaminated food or water)
Treatment:- praziquantel
Diphyllobothrium Latum
Transmission:- ingestion of larvae in freshwater fish
Causes:- macrocyctic anaemia —? Competes with Vitamin B12
Mgx:- praziquantel
Echinococcus granulsus
Transmission:- ingestion of eggs in food contaminated with dog faeces
Causes:- hydatid cysts in liver and lung —> if rupture can cause anaphylaxis
Mgx:- Albendazole
Schistosoma
Transmission:- snails in conataminated freshwater
Schistosoma Mansoni and japonicum —> diarrhoea illness abdo pain iron def anaemia
Schistosoma haematobium:- Sq cell carcinoma of the bladder —> painless haematuria
Mgx:- praziquantel
Chlonorchis sinesis
Transmission:- undercooked fish
Causes:- biliary tract inflammation, cholangiocarcinoma
Mgx–> praziquantel
Yersinia Pestis
G-ve bacilli, oxidase -ve , no H2 production
Exhibits bipolar staining (resembles safety pin)
Transmission:- rodents
Causes:- bubonic plague—> fever, headache, painful swollen erythematous LNs ( buboes)
Neisseria Meningitidis
G-ve diplococci, aerobic, ferments maltose and glucose
Virulence:-
Pediculus humanus capitus
Head lice
Transmission is directly
Diagnosis:- inspection of egg attached to hair shaft
Mgx:- permethrin
Tinea corporis (Dermatophyte infections)
Tinea corporis, Tinea pedis, Tinea Cruris
Infection keratinised matter but don’t invade the dermis or subcutaneous tissue (i.e ltd to keratinised structures)
Corynebacterium Diphtheria
G+ve rods non motile
Stains with aniline dyes ( methylene blue)
Virulence:- AB exotoxin inhibits cell protein synthesis by catalysing ADP ribosylation of hot cell elongation factor -2
Transmission:- resp droplets
Complications:- myocarditis, neurotoxin
Pox virus
Enveloped DsDNA virus linear ( large virus)
Replicated in cytoplasm
No icosahedral
Eradicated by live attenuated vaccine
Causes:-milkmaid blisters, Molluscum contagiosum
Hepadna virus
Enveloped DsDNA virus, circular
Replicates in nucleus
Isocahedral capsule
Causes:- HBV
Herpes virus
Enveloped dsDNA linear virus
Replicates in cytoplasm
Isocahedral capsule
Family members :- HSV, EBV, CMV, VZV HHV
Adenovirus
Naked dsDNA linear virus
Isocahedral capsule
Replicated in nucleus
Causes:- pharyngitis, conjunctivitis, pneumonia, gastroenteritis, myocarditis
Papillomavirus
Naked dsDNA circular
Isocahederal capsule
Replicate in nucleus
Causes:- HPV —> warts, penile, Anal, Cx , oropharygeal cancer
Polyomavirus
Naked dsDNA circular
Isocahedral capsule
Replicate in nucleus
Causes:- JC virus:- progressive multimodal leukoencephalopathy in immunocompromised
BK virus:- transplant pts, targets kidneys
Parvovirus
Naked, ssDNA linear (smallest dna virus)
Replicated in nucleus
Isocahedral capsule
Causes: - B19 aplastic crises in sickle cell disease, slapped cheek in children, hydros fetalis
Naked Halle’s Pico de galleo is Really Positively Crunchy
Naked +ve RNA viruses
Hepevirus (HEV)
Picornavirus (PERCH)
Reovirus (Rota)
Calciviruses (Noro)
Have Helpful Protection
Enveloped DNA virus
Herpesvirus
Hepdna virus
Poxvirus
You get Naked for a PAPP smear
Naked DNA viruses
Papilloma virus
Adenovirus
Polyomavirus
Parvovirus
Run TO Flavs Corona Envelope Party
Enveloped +ve RNA
Retrovirus
Togavirus
Flavivirus
Coronavirus
BAD People Run From Officers
-ve RNA enveloped
Bunyavirus
Arenavirus
Delta virus (HDV)
Paramyxovirus
Rhabdovirus
Filovirus
Orthomyxovirus
Reovirus
Naked +ve dsRNA segmented virus
Isocahedral capsule
Replicate in cytoplasm
Causes:- rotavirus
Picornavirus
Naked +ve ssRNA linear
Isocahedral capsule
Replicates in cytoplasm
Causes: (PERCH)
Poliovirus
Echovirus ( aseptic meningitis)
Rhinovirus
Coxasckie virus (hand foot and mouth)
HAV
Hepevirus
Naked +ssRNA linear
Isocahedral capsule
Replicate in cytoplasm
Causes HEV
Calcivirus
Naked +ssRNA linear
Isocahedral capsule
Replicates in cytoplasm
Causes:-norovirus
Flavivirus
Enveloped +ssRNA, linear
Isocahedral capsule
Replicate in cytoplasm
Causes :- HCV
Yellow fever
West Nile
Dengue
Zika
Togavirus
Enveloped +ssRNA linear
Isocahedral capsule
Replicates in cytoplasm
Causes:- Rubella (matonavirus)
Retrovirus
enveloped +ssRNA linear
Isocahedral capsule
Replicate in nucleus
Has reverse transcriptase inhibitor
Causes:- HIV, HTLV - T cell leukaemia
Coronavirus
Enveloped +ss RNA linear
NO Isocahedral capsule
Replicates in cytoplasm
Causes cold, SARS , COVID 19
Paramyxovirus
Enveloped -ve ssRNA linear
Helical capsule
Replicates in cytoplasm
Causes:- parainfluenza (croup)
RSV
Measles, mumps
Orthomyxovirus
Enveloped -ve ssRNA linear
Helical capsule
Segmented
Actinomyces
G+ve branching filamentous bacteria
Transmission:- introduced to submucosa during mechanical trauma ( tooth extraction)
Causes:- slowly growing, non painful, chronic mandibular mass evolves into multiple abscess and sinus tract
Yellow orange sulfur granules
Ascaris lumbricoides
Roundworm
Common in Asia, Africa S. America
Transmission:- eggs ingested via contaminated food/water
Eggs hatch to larvae, penetrate intestinal wall and migrate to alveoli —> Loffeler syndrome ( cough, wheeze, SOB)
EBV testing
Infects B cells stimulating them to proliferate continuously -immortalisation
and heterophile antibody production
Heterophile antibody test is sensitive and highly specific for EBV —> diagnosis in Vivo infection
Coccidioides Immitis
Dimorphic fungi
Endemic to US and Mexico
Appearance:- thick walled spherules packed with endospores larger than RBC
Causes:- pulmonary disease
Molluscum contagiousum
Caused by pox virus
Small firm shiny rounded papules with central indentation
Biopsy:- intracytoplasmic eosinophils inclusion bodies
Pasturella multocida
G-ve cocobacilli ( mouse like odour)
Exposure:- dog or cat bite
N part of upper resp tract flora in animals
Presentation:- within 24 hrs of bite , cellulitis symptoms and signs
Listeria monocytogenes
G+ve rod faculatative intracellular
Tumbling, motile, rocket tails
Virulence:- listeriolycin O ( enzyme that creates pores in phagosomes)
Transmission:- dairy and cold deli meats, placental transmission
Presentation:- febrile gastroenteritis, spontaneous abortion, meningitis in immunocompromised
Enterococcus
G+ve cocci catalase -ve
Gamma haemolytic (no haemolysis)
PYR +ve
Grows in bile and 6.5% NaCl
Causes:- UTI, cholecystitis, subacute endocarditis
Commonly cause infections after cystoscopy, colonoscopy or ob procedures
Scarlet fever
Cause: Group A streptococcus producing exotoxin
presentation:- follows pharyngitis. Maculopapular Rash, sand paper like. Cheeks are flushed pallour around mouth. Followed by desquamation. Strawberry tongue
Complications:- rheumatic fever, glomerulonephritis
Mgx:- penicillin V will prevent rheumatic fever but not GN
Bacteria with low infectious dose
Shigella
Shiga toxin E.Coli
Yersinia pestis
Giardia
Campylobacter jejuni
Strep pyrogenes virulence
M protein shares structure characteristics with tropoMyosin and Myosin
Prevents phagocytosis
Viridans streptococci
G+ve cocci
Alpha haemolysis
Optochin resistant not bile soluble
Produce dextran from sucrose
Normal in mouth
Cause:- dental caries, endocarditis
Common pathogens causing nosocomial blood stream infection
Coag negative staph
Staph aureus
Enterococci
Candida
Cause increased in numbers is intravasulcal catheters
Cryptosporidium parfumerie
Faeco-orally transmitted protozoa
Acid fast oocytes in stool
Causes water diarrhoea in immunocompromised
