Microbiology Flashcards
Grape-bunch clusters
Staph aureus
Sensitive to optochin
Strep pneumoniae
Resistant to optochin
Strep viridans
Virus causing clumsiness, weakness, vision changes in “recent transplant”
JC Virus (causing Progressive Multifocal Leukoencephalopathy)
Recent transplant = immunosuppresed
Virus in bone marrow transplant patient
Adenovirus
Fever, malaise, raised ALT in person coming from India
Hepatitis A
Illness in person who had “transfusion long time ago”
Hepatitis C
Mutation allowing Spanish Flu and H5N1 to enter humans and mess us up
PB2 Mutation
Blueberry muffin rash
Congenital Rubella Syndrome
Slapped Cheek Syndrome
Parvovirus B19 (erythema infectiosum = Fifth Disease)
Most common valve affected in endocarditis in IV drug users
Tricuspid (valve connecting right atrium to right ventricle)
Ischaemic tongue
Giant Cell Arteritis
Temporal artery biopsy
Giant Cell Arteritis
Rusty colour sputum
Strep pneumonia
Gram +ve diplococci
Pneumonia in COPD patients
Haemophilus influenzae
Gram -ve cocci
Pneumonia after viral infection
Staph aureus
Gram +ve grape-bunch clusters (cocci)
Pneumonia after old AC system (“hotel room”)
Legionella - due to stagnant water
Gram -ve rod
Pneumonia with erythema multiforme
Mycoplasma pneumoniae
Pneumonia from farm animals
Coxiella burnetti (Q Fever)
Pneumonia after bird exposure
Chlamydia psittaci
Pneumonia in alcoholic (causes haemoptysis)
Klebsiella
Gram -ve rod
Bugs after splenectomy
Encapsualted organisms = strep pneumonia, haemophilus, neisseria
Ground-glass shadowing and “bat’s wing” appearance on CXR
Pneumocystis Jirovecii (PCP) Desaturates during 6-min walk test
Form of malaria when mosquito injects into blood
Sporozite
Aedes mosquito causes what?
Dengue (flavivirus)
Blanching rash, which looks like “islands of white in sea of red” in recovery phase
Dengue
Rose spots
Typhoid
Atypical lymphocytosis
Infectious Mononucleosis (EBV)
Target-shaped rash with central fading
Lyme Disease (borrelia burgdoferi)
Food poisoning from chickens
Campylobacter
Bug from cat scratches
Bartonella
Bug from unpasteurised milk
Brucellosis
Bug from dog bites
Lyssa virus (= rabies)
Sight of water causes convulsions and paralysis
Rabies
Nematode that pops out when have fever/anaesthetic
Ascaris (most common helminth)
Nematode causing protracted eosinophilia
Filariasis
Ghon Complex on CXR
Latent TB (Ghon Complex resolves to Ghon Focus = scarring and calcification)
Sudden-onset flank pain, radiating to groin
Spinal TB
Stain used for Acid Fast Bacilli test
Auramine or Ziehl-Neelson
Agar used for TB culture
Lowenstein-Jensen medium
TB drug causing optic neuritis
Ethambutol
TB drug causing lucozade secretions
Rifampicin
TB drug causing you to get pregnant on OCP
Rifampicin (increases hepatic metabolism of other drugs)
TB drug causing peripheral neuropathy
Isoniazid
Fungal infection of lung in AIDS patients
Cryptococcus
Halo Sign on chest CT
Aspergillus
Air Crescent Sign on chest CT
Aspergillus
Antifungal causing nephrotoxic
Polyenes (like Amphotericin B)
Antifungal interacts with warfarin
Azole (interacts with human P450 enzymes)
Tumbling motility
Listeria
India ink stain
Cryptococcus
Meningitis bug found in eggs/cheese/mayo
Listeria
Gas gangrene in infected wounds
Clostridium pefringens
Pneumonia after travelling from abroad (Mexico)
Mycoplasma
Bitten by another man. Wound becomes pus and foul-smelling
Anaerobes
GI infection after eat reheated rice
Bacillus cereus
Gram +ve rod
GI infection after BBQ
Salmonella enteritidis
Rice-water stool
Vibrio cholera
Gram -ve comma shaped
GI infection after Canned and vacuumed foods
Clostridium botulinum
GI infection if less than 1 year old eats honey
Clostridium botulinum
GI infection after eat refrigerated food (especially sandwiches)
Listeria
Beta-haemolytic anaerobic Gram +ve rods
Traveller’s Diarrhoae
ETEC (Enterotoxigenic E. Coli)
GI infection after sushi (undercooked seafood)
Vibrio parahaemolyticus
GI infection with foul-smelling diarrhoae
Campylobacter
Gram -ve curved
GI infection causing cellulitis in shellfish handlers
Vibrio vulnificus
GI infection causing Guillan-Barre Syndrome
Campylobacter
Gram -ve curved
Protozoal GI infection causing flask-shaped ulcer
Entamoeba histolytica
Protozoal GI infection causing pear-shaped trophozites, foul-smelling stool and flatulence
Giardia lamblia
Protozoal GI infection from swimming pools
Cryptosporidium parvum
Protozoal GI infection diagnosed using string test
Giardia lamblia
Most common diarrhoea in infants
Rotavirus
Persistent bone pain, with chronic overlying infection (diabetic ulcers)
Osteomyelitis
Pulvinar Sign on MRI
Variant Creutzfeldt-Jakob Disease
- seen in young only
Cause of UTI in young women
Staph saprophyticus
Organism causing staghorn calculi
Proteus mirabilis (causes recurrent UTI)
Clue cells on microscopy
Bacterial vaginosis
STI with thin white vaginal discharge
Trichomonas vaginalis
GUM disease caused by excessive douching
Bacterial vaginosis
Chocolate agar medium used to diagnose this STI
Chancroid = haemophilus ducreyi
Whiff Test
Bacterial vaginosis (get fishy smell when add hydrogen peroxide to sample)
What causes Roseola Infantum?
HHV6
Long-term prophylactic treatment for post-splenectomy patients
Penicillin V
Returned from Mediterranean with undulant fever
Brucellosis
Ulcerating papule, with necrotic centre. Gram +ve rods, responds to penicillin
Bacillus anthracis
Itchy, scaly rash on soles of feet – what fungi?
Trichophytum rubrum
Neutrophilia with visible toxic granulation and vacuoles on the blood film
Acute fungal infection
Gomori’s methenamine silver stain shows “flying saucer” cysts on microscopy
Pneumocystis Jirovecii
Bug in refrigerated food and unpasteurised milk
Listeria monocytogenes
Stomach bug causing anaemia and thrombocytopaenia
E. coli 0157 - causes HUS:
- Haemolytic anaemia
- Uraemia (AKI)
- Thrombocytopaenia
Microscopic agglutination test positive
Leptospira interrogans
- Zoonosis
- Non-specific symptoms –> meningitis and liver failure
Thayer-Martin VCN medium
Neisseria meningitides
Painless ulcer on genitals which self-heal
Lymphogranuloma venereum
Cause of lymphogranuloma venereum
Chlamydia trachomatis
Important side effect of ganciclovir
Bone marrow toxicity (so can give G-CSF with it)
Mechanism of action for aciclovir?
Converted to acyclo-GNP by viral thymidine kinase
- -> phosphorylated to acyclo-GTP
- ->acyclo-GTP incorporated into viral DNA strand, termination DNA chain, stopping DNA polymerase from working
Fever and cough –> haemolytic anaemia, +ve for cold agglutinins
Mycoplasma pneumoniae
Moderate leg pain – X-Ray: a well defined ovoid shape with a surrounding sclerotic margin but little involucrum in his tibia
Brodie’s abscess = subacute osteomyelitis, which can persist for years
“Recently started working at farm”
Brucellosis
Main cause of meningitis in:
- Neonates
- Kids
- Adolescents
- E coli and GBS
- Strep pneumoniae!
- Neisseria meningitidis
Most common Hepatitis in IVDU
Hep B
Hepatitis associated with old blood transfusions
Hep C
UTI always associated with functional/anatomical abnormalities of the renal tract. Also causes cavitating pneumonia.
Klebsiella
Causes haemorrhagic cystitis in children
Adenovirus
Dyspnoea after exposed to “building work”
Aspergillus fumigatus
Gram +ve cocci in chains, which grew on MacConkey plate and was aesculin-positive. Resistant to the conventional anti-streptococcal antibiotics.
Vancomycin-resistant enterococcus (VRE)
Seen in burns victims. Gram -ve bacilli that produced a green pigment and was oxidase-positive
Pseudomonas aeruginosa
Hypopigmented spots in dark skin/hyperpigmented in light skin
–> microscopy with KOH shows “spaghetti with meatballs” appearance
Pityriasis versicolour = Malassezia
Stain used for Pneumocystis jirovecii
Gomori’s methenamine silver stain
Malaria causing a fever every 4 days (quartan malaria)
Plasmodium malariae
Malaria causing a fever every day (quotidian malaria)
Plasmodium knowlesi
-all other malarias cause fever every 3 days
Malaria originating in SE Asia (not Africa)
Plasmodium knowlesi
Form of malaria that is injected into blood
Sporozite
Form of malaria that invades RBCs
Merozite
Maurer’s Clefts seen in thin blood film
Plasmodium falciparum
Schuffner’s Dots seen in thin blood film
Plasmodium vivax and ovale
Diarrhoea, vomiting and smelly burps
Giardia Lamblia
Stool shows cysts and “tear-drop” shaped trophozoites
Giardia Lamblia
Neonate with recurrent seizures and intracranial calcification
Congenital toxoplasmosis
STI which is gram negative oxidase positive diplococci
Neisseria gonorrhoea
STI which cannot be grown on agar, but can be grown on tissue medium
Chlamydia trachomatis
Girl with diarrhoea – duodenal biopsy shows motile trophozites and partial villous atrophy
Giardia lamblia
Treatment: metronidazole
Influenza binds to what on target cells?
Sialic acid
The receptor binding and membrane fusion glycoprotein of influenza virus
Haemagluttinin
What part of influenza allows it to leave the target cell?
Neuraminidase
Bacteria which lack cell wall
Mycoplasma
Route for C. diff meds
Oral!
Newborn ashen grey, vomiting, haemodynamically unstable after taking this antibiotic
Chloramphenicol –> causes Grey Baby Syndrome
Used to treat contacts of meningococcal
Rifampicin
Antibiotic mechanism: bind to transpeptidases –> inhibits peptidoglycan layer formation
Beta-lactams
Antibiotic mechanism: binds to amino acids in peptidoglycan –> prevents glycosidic bonds and peptide cross-links
Glycopeptides (vancomycin, teicoplanin)
Antibiotic mechanism: binds to 30s ribosomal subunit –> prevents peptide elongation
Aminoglycosides = end in –cin (gentamicin, tobramycin)
Antibiotic mechanism: binds to 30s ribosomal subunit –> prevents tRNA binding
Tetracyclines
Antibiotic mechanism: bind to 50S ribosomal subunit –> inhibit ribosomal translocation and association of peptidyl-tRNA to amino acids
Macrolides
Antibiotic mechanism: binds to 23S component of the 50S subunit –> prevent formation 70S initiation complex (necessary for translation)
Oxazolidinones = end in –zolid (linezolid)
Antibiotic mechanism: inhibit DNA gyrase –> prevent DNA unwinding and replicating
Fluoroquinolones = end in –floxacin (ciprofloxacin)
Antibiotic mechanism: breaks DNA strand in anaerobic conditions
Nitroimidazoles = end in –idazole (metronidazole)
Severe diabetic with facial pain and black nasal discharge –> need urgent surgical debridement
Mucormycosis (inhale Mucor/Rhizopus species)
Infection causing “owl’s eyes” appearance in cells
CMV
Flagellate protozoan that can cross placenta
Toxoplasmosis
STI that can cross placenta in third trimester
Syphilis
This suggests contamination of urine sample
Epithelial cells on microscopy
Cause of erysipelas (well-demarcated lesions on skin, with rigors/fevers)
Group A Strep
Non-healing skin lesion in Afghanistani
Cutaneous Leishmaniasis
Cause of post-transplant lymphoproliferative disease
EBV
Erythema migrans
Target lesion in Lyme Disease
Malaria drug against organisms in blood
ACT (artemisin)
Malaria drug against organisms in liver
Primaquine
Granuloma with central necrosis
TB
Measles belongs to which class of virus?
Paramyxovirus
Ring-enhancing lesions on CT Head in immunodeficient
Toxoplasmosis
Treatment: pyrimethamine and sulfadiazine
Fundoscopy: retina looks like “pizza pie”
CMV Retinitis
What do beta-lactams bind to?
Transpeptidase
Antibiotic class causing photosensitivity
Tetracyclines (doxycycline in acne!)
Can be used for the treatment of influenza A, but does not work against influenza B
Amantadine
Hep B surface antigen (HBsAg)
Current infection
Hep B “e antigen” (HBeAg)
High infectivity
Hep B core antibody (anti-HBc)
Previous infection (c = caught)
Hep B surface antibody (anti-HBs)
Immunity
Anti-HBc AND anti-HBs
Immune due to infection
Only anti-HBs
Immune due to vaccine
Treatment of Hep B
PEGinterferon-a and tenofovir
Treatment of Hep C
PEGinterferon and ribavirin
Treatment of Hep E
Ribavirin
Type of vaccine: MMR
Live attenuated
Type of vaccine: influenza, polio
Inactivated
Type of vaccine: Hep B, HPV
Subunit
Type of vaccine: HiB
Conjugate
Diagnosis toxoplasmosis in pregnancy
T. gondii DNA in amniotic fluid (PCR)
Treatment toxoplasmosis in pregnancy (<18 weeks)
Spiramycin
Treatment toxoplasmosis in pregnancy (>18 weeks)
Pyrimethamine + sulfadiazine + calcium folinate
Definition of severe falciparum
Parasitaemia >2%
Treatment of mild falciparum
ACT = Artemisinin Combination Therapy
Treatment of severe falciparum
IV artesunate –> oral ACT
Treatment of non-falciparum
Chloroquine (3 days) + primaquine (14 days)
Treatment of typhoid
IV ceftriaxone (2g OD) --> azithromycin 500mg BD for 7 days
Most common cause of adult-onset epilepsy
Cysticercosis
Treatment of Cysticercosis
Praziquantel and steroids
Treatment of hydatids
PAIR (drainage of cysts) –> long-term praziquantel
Medium used to culture fungi
CHROMagar Candida medium, with Pal’s agar
Assay used for fungi serology
βD Glucan Assay
Treatment of empirical fungi/non-Candida albicans
Echinicandin (e.g. anidulafungin)
Treatment of organ-based fungal disease
Ambisome = IV fluconazole/amphotericin B
Diagnosis of cryptococcus
Cryptococcal antigen in blood/CSF
Treatment of cryptococcus
3 weeks of amphotericin B + flucytosine
Fungi use this compound in their cell membranes
Ergosterol (targeted by azoles and polyenes)
If >50/immunocompromised, what do you add to treatment of meningitis and encephalitis?
IV amoxicillin 2g 4hourly (covers listeria)
Polymorphism associated with Prion Disease
MM polymorphism on codon 129 on Prion gene
Brain histology shows spongiform vacuolation
CJD
Treatment of complicated UTI
Cefalexin
Treatment of cryptococcus
Amphotericin B
Treatment of giardia
Metronidazole 400mg TDS for 5 days
TB drug causing gout and arthralgia
Pyrazinamide
Treatment C. diff
Mild-moderate: metronidazole
Severe: vancomycin
Conjunctivitis and erythematous, coalescing rash
Rubella
Gram+ cocci, catalase +ve and coagulase +ve
Staph aureus
Gram- cocci, maltose fermenter
Neisseria meningitidis
Smear from the genital ulcer base is positive to dark-field examination
Treponema pallidum (syphillis)
Genital ulcer and matted inguinal lymph nodes with abscess/sinus formation
Lymphogranuloma venereum (chlamydia)
Milky urethral discharge in man
Gonorrhoea
Stain used for H. pylori
Giemsa stain
Comma-shaped Gram-ve causing diarrhoea
Vibrio cholera
Gram negative rod which turns MacConkey agar red
E. coli
Cause of cutaenous leishmaniasis
Leishmania major
Normal CSF ranges
WBCs 0-5
Protein 0.15-0.40
Glucose 2.2-3.3
Definition of low CSF glucose
CSF glucose less than 2/3 of serum glucose
Bartonella in immunocompromised
Bacillary angiomatosis
Viral thymidine kinase converts aciclovir to what?
Aciclovir monophosphate
What form of aciclovir inhibits the action of viral DNA polymerase?
Aciclovir triphosphate
Atypical bug specific for CF
Burkholderia cepacia
Long-term prophylactic treatment for post-splenectomy patients
Penicillin V
STI presents as a shallow painful ulcer, sometimes progressing to a lymphadenopathy
Chancroid
