1. Core Microbiology Flashcards
What bacterial classification is ‘Staphylococcus aureus’?
Gram + cocci
What bacterial classification is ‘Heamophilus’?
Gram - coccobacilli
What bacterial classification is ‘Helicobacter’?
Spiral bacteria
What bacterial classification is ‘Neisseria meningitidis’?
Gram - cocci
What bacterial classification is ‘Escherichia coli’?
Gram - bacilli
What bacterial classification is ‘Clostridium difficile’?
Gram + bacilli
What bacterial classification is ‘Streptococcus pyogenes’?
Gram + cocci
What bacterial classification is ‘Brucella’?
Gram - coccobacilli
What bacterial classification is ‘Neisseria gonorrhoeae’?
Gram - cocci
What colour stain indicates Gram + bacteria?
Blue/Black (purple)
they have a thick peptidoglycan cell wall which retain the stain
What colour stain indicates Gram - bacteria?
Pink/Red
thinner cell wall, they are counter stained after the gram stain which gives the red colour
What bacteria is found in the noses of up to 50% of people?
Staphylococcus Aureus
induces an immune response if there is a cut in the skin and it gets into it
What is the most common cause of skin/soft tissue infection?
Staphylococcus aureus
staphylo = bunch of graps in Greek
An opportunistic pathogen found on most peoples skin.
Associated with infections involving intravascular catheters/prosthetic joints/prosthetic cardiac valves.
Staphylococcus epidermidis
Commonest cause of bacterial sore throat.
Streptococcus pyogenes (Group A Strep)
strepto = chain in Greek
Commonest cause of bacterial pneumonia & meningitis (except in neonates)
Streptococcus pneumoniae
Commonest cause of bacterial meningitis in neonates (babies under 3 months)
Streptococcus agalactiae
Streptococcus milleri is associated with what?
Abscesses - dental, liver, lung, brain etc.
Group of species which inhabit the upper respiratory tract and are a classic cause of acute bacterial endocarditis.
Viridans streptococci
Gram + bacillus, classic cause of diphtheria.
Corynebacterium species
(corynebacterium diphtheriae)
rarely seen in the UK now due to vaccinations
Gram + bacillus, associated with acne.
Propionibacterium acnes
Commonest cause of urinary tract infection (UTI)
E. coli
Commonest cause of bacteraemia.
E. coli
causes a lot of bloodstream infections
Multi-resistant gram - bacillus which has a characteristic green pigment.
Can cause respiratory infections, UTI’s
Pseudomonas aeruginosa
Gram - diplococcus, causes meningococcal sepsis and meningitis.
Neisseria meningitidis
Cause of gonorrhoea.
Neisseria gonorrhoeae
The Clostridium species are anaerobes, what does this mean?
Grow in the absence of oxygen.
Mycobacterium tuberculosis causes TB.
This mycobacterium species is referred to as the ‘Acid Fast Bacilli’. Why?
They don’t stain with gram stain.
They require ‘Acid Fast’ stains.
Most common respiratory tract infection.
Mycoplasma pneumoniae
Most commonest cause of STI.
Chlamydia trachomatis
Cause of syphilis.
Treponema pallidum
Spirochaetes
Which of the following can cause meningitis?
A] Neisseria meningitidis B] Streptococcus pneumoniae C] Listeria monocytogenes D] Streptococcus agalactiae E] Haemophilus influenzae F] Staphylococcus aureus
ALL of them
Which of the following is the most common sexually transmitted infection?
A] Chlamydia trachomatis B] Treponema pallidum C] Corynebacterium diphtheriae D] Staphylococcus aureus E] Neisseria gonorrhoeae F] Viridans streptococci
A
Which of these bacteria is a common cause of skin infection?
A] Klebsiella pneumoniae B] Streptococcus pneumoniae C] Haemophilus influenzae D] Neisseria meningitidis E] Staphylococcus aureus F] Clostridium difficile
E
Which of the following are ‘Gram Negative’ bacteria?
A] Streptococcus pneumoniae B] Mycobacterium tuberculosis C] Escherichia coli D] Listeria monocytogenes E] Neisseria gonorrhoeae F] Mycoplasma pneumoniae
C and E
What are fungi cell wall made of?
Glucan-chitin (mainly carbohydrates)
What are the 3 types of fungal disease?
- Superficial infection - skin, hair , nails
(dermatophytes, Malassezia, Candida) - Subcutaneous infection
- Systemic infection - organs
(Candida, Aspergillus)
Which of these is a Dermatophyte infection of the groin area known as ‘Jock itch’?
- Tinea pedis
- Tinea unguium
- Tinea cruris
- Tinea corporis
- Tinea capitis
- Tinea barbae
- Tinea cruris
More common in men.
Itching, scaling, erythematous (redness).
Cause: T. rubrum
Which of these is a general Dermatophyte infection of the torso and limbs known as ‘ringworm’?
- Tinea pedis
- Tinea unguium
- Tinea cruris
- Tinea corporis
- Tinea capitis
- Tinea barbae
- Tinea corporis
like corpse
Which of these is a Dermatophyte infection of shaved skin on the face?
- Tinea pedis
- Tinea unguium
- Tinea cruris
- Tinea corporis
- Tinea capitis
- Tinea barbae
- Tinea barbae
like barber
Which of these is a Dermatophyte infection of the nails known as ‘fungal nail disease’?
- Tinea pedis
- Tinea unguium
- Tinea cruris
- Tinea corporis
- Tinea capitis
- Tinea barbae
- Tinea unguium
Destruction of the nail starting with white patches on the nail.
5-25% of adults, increasing incidence in elderly.
Causes: Trichophyton rubrum + T. interdigitale
Which of these is a Dermatophyte infection of the scalp and hair known as ‘scalp ringworm’?
- Tinea pedis
- Tinea unguium
- Tinea cruris
- Tinea corporis
- Tinea capitis
- Tinea barbae
- Tinea capitis
(like wearing a cap)
most common in prepubescent children
inflammation, scaly patches, alopecia, black dots.
Severity of inflammation depends on whether the fungi is zoophilic (from animals) or anthrophilic (from humans).
Which of these is a Dermatophyte infection of the feet known as ‘Athletes foot’?
- Tinea pedis
- Tinea unguium
- Tinea cruris
- Tinea corporis
- Tinea capitis
- Tinea barbae
- Tinea pedis
More common in adult men.
Can affect one or both feet.
Cause: Trichophyton rubrum
How is Tinea capitis treated?
Systemic antifungals
e.g.
Griseofulvin
Terbinsfine
Itraconazole
Lesions of hyper/hypopigmented skin in the upper trunk, between puberty and middle age.
What is this and how is it treated?
Pityriasis versicolor
A type of Malassezia
(what you had on your neck time ago)
Topical antifungals e.g. clotrimazole
If fails = oral antifungal: fluconazole / intraconazole
Large genus of yeasts which can infect almost any organ in the body, associated with thrush.
What species is the most common?
Candida
Candida albicans is most common
Inflammation of vaginal epithelium, may extend to labia.
Affects 70-80% of women at least once. Associated with pruritis (itching), burning sensation and discharge.
What is it and how is it treated?
Candida vulvovaginitis
Oral antifungals e.g. fluconazole
How are pregnant women with Candida vulvovaginitis treated?
Topical azoles e.g. clotrimazole
DO NOT USE ORAL AZOLES
(e.g. fluconazole)
these increase the risk of tetratologies.
Give 4 examples of candida infections.
- Candidaemia - diagnosed in blood culture
- Candida oesophagitis - mainly in HIV, diagnosed with endoscopy biopsy
- Candida endocarditis - vegetation on heart valves (affects IV drug users and valve surgery patients)
- Renal candidosis - candida in blood gets stuck in kidney tissue during filtration
- Urinary tract Candida infection - more common in women, diabetics, damaged/abnormal urinary tracts
- Candida peritonitis - diagnosed with a Candida culture from peritoneal fluid
- Heptaosplenic candidosis
A genus of moulds (filamentous fungi) which produce airborne spores that you are exposed to via inhalation.
Aspergillus
What is an Aspergilloma?
A solid ball of fungus which occupies cavities in the body (mainly lung) made by previous TB infections or surgery.
These can be present for a while and not cause an issue UNLESS they break up. Causing haemoptysis and are potentially fatal.
An allergic reaction to Aspergillus can cause what?
Asthma
Cystic fibrosis
Fungal pathogen which causes pulmonary or sinus disease?
Aspergillus
Dermatophytes are….?
A - Mites that live on the skin
B - Fungi that infect skin hair and nails
C - Fungal pathogens frequently grown in blood culture
D - Bacteria found on the skin
E - Skin lesions giving the appearance of plants
B
Candida is…..?
A - Yeasts causing superficial and systemic infection
B - A play by Ibsen
C - Yeasts only causing oral infection
D - Yeasts causing infections that are always treated with fluconazole
E - Moulds causing pulmonary disease
A
Aspergillus is….?
A - A mould that always causes of invasive disease
B - A mould that always allergic disease
C - A yeast that causes pulmonary disease
D - A mould that causes pulmonary disease
E - A mould that always causes skin disease
D
Aspergillus can cause invasive and other infections
Aspergillus can cause allergic and other disease
Aspergillus is a mould not a yeast
Aspergillus does mainly cause pulmonary disease
Aspergillus rarely causes skin infection
What is the cause of Tinea cruris?
Trichophyton Rubrum / T. Rubrum
What is the cause of Tinea pedis?
Trichophyton Rubrum / T. Rubrum
What is kerion celsi a complication of?
Tinea capitis
severe form that is usually animal derived
A group of keratinophilic fungi.
Dermatophytes
Tinea pedis which affects the entire sole of the foot.
Moccasin foot
What does S. Aureus produce to stimulate a host response?
Exoenzymes and toxins
Most common cause of UTI and bacteraemia.
E.coli
Otitis media can be caused by what bacteria?
Streptococcus Pneumoniae
also causes pneumonia + meningitis
Bacterial cause of meningitis in neonates.
Streptococcus Agalactiae
Classic cause of bacterial endocarditis (vegetation).
Viridans Streptococci
Classic cause of gas gangrene.
Clostridium Perfringens
Which 2 bacterial species do not have a conventional cell wall?
Chlamydia species + Mycoplasma species
Most common cause of STI.
Chlamydia Trachomatis
Cause of syphilis.
Treponema Pallidum
Prokaryotes lack introns and organelles.
True or False?
TRUE
eukaryotes have both introns in their genes and membrane bound cell organelle.
Topical antifungal treatment for dermatophytes?
Clotrimazole
+ Terbinafine (oral + topical versions)
How is Tinea Capitis treated?
SYSTEMIC antifungals:
Griseofulvin OR Terbinafine
Pityriasis versicolor is caused by what type of fungi?
hyper- or hypopigmented lesions on skin
Malassezia (yeast)
Cause of oral/vaginal thrush.
Candida Albicans (most common Candida)
Very common yeast infection in women that presents with pruritis.
Candida vulvovaginitis (vaginal yeast infection)
Antifungal treatment against Candida?
Fluconazole (oral)
Antifungal treatment against Candida in pregnant women?
Clotrimazole (topical)
fluconazole and other oral azoles increase the risk of teratologies.
Most common Candida?
Candida Albicans
How is aspergillus spread?
Inhalation of spores
A herpes virus which causes chicken pox.
Varicella zoster virus
reactivates to cause herpes zoster/shingles
80-90% of infectious mononucleosis or ‘glandular fever’ is caused by what?
Epstein Barr virus
rest is caused by CMV
What does Rhinovirus cause?
common cold
Virus that causes bronchiolitis?
Respiratory syncytial virus
At what point is HIV classed as AIDS?
- Increase in viral load
- Drop in CD4 count
- Opportunistic infections e.g. cryptococcal meningitis, tuberculosis, pneumocytic pneumonia
dsRNA Virus of childhood, affecting everyone with first 3 years of life. Associated with fever, vomiting, watery diarrhoea.
Rotavirus
Coxsackie A is associated with pericarditis.
True or False?
FALSE
Coxsackie A = herpangina (mouth blisters)
Coxsackie B = pericarditis
Erythema infectiosum ‘Slapped cheek syndrome’ is caused by what virus?
Parvovirus B19
A virus which can trigger Transient aplastic crisis in patients with hemoglobinopathies?
Parvovirus B19
What is a prion?
Small infectious protein pathogen with no nucleic acid
e.g. nvCJD
A spongiform change in brain tissue is associated with what pathogen?
Prion
A drug used for the treatment of giardiasis?
Metronidazole
The commonest organ affected by a hydatid cyst?
Liver
A sexually transmitted parasitic disease?
Trichomoniasis
