MLT GlobeASCP exam preparation (USA · MLS / MLT) – page 17
1200 practice MCQs for the ASCP medical laboratory exam. Level: Advanced.
Gram-positive cocci arranged in chains most likely belong to which genus?
Streptococci divide in one plane and form chains; staphylococci form clusters and micrococci form tetrads.
Which organism is the most common cause of acute osteomyelitis?
S. aureus causes most cases of acute osteomyelitis in all age groups.
Necrotising fasciitis ('flesh-eating' infection) is classically caused by:
Group A streptococcus is the classic cause of rapidly spreading necrotising fasciitis.
On a Gram stain, Bacillus anthracis typically appears as:
B. anthracis forms large, square-ended Gram-positive rods in long chains, often described as a 'bamboo stick' appearance.
Which Gram-positive rods (Döderlein's bacilli) keep the healthy vaginal pH acidic?
Lactobacilli produce lactic acid from glycogen, keeping vaginal pH low and protecting against pathogens.
The diphtheria component of the DTP vaccine is a:
Diphtheria vaccine is toxin treated with formaldehyde (toxoid), which induces antitoxin antibodies without causing disease.
Salmonella Typhi is usually acquired by:
Typhoid spreads by the faecal-oral route, often from carriers or contaminated water.
On a TSI slant, blackening of the butt indicates:
H2S reacts with ferrous ions in the medium to form black ferrous sulphide.
In a hanging-drop preparation of fresh stool, Vibrio cholerae shows which type of motility?
A single polar flagellum gives V. cholerae rapid darting motility, which is stopped by specific antiserum.
Which test for syphilis detects antibodies against Treponema pallidum antigens (a treponemal test)?
TPHA detects specific antibody to T. pallidum; VDRL and RPR are non-treponemal tests using cardiolipin antigen.
Scrub typhus (Orientia tsutsugamushi) is transmitted by:
Scrub typhus is spread by the bite of larval trombiculid mites, which often leaves an eschar.
Lyme disease, caused by Borrelia burgdorferi, is transmitted by:
Hard ticks of the genus Ixodes transmit B. burgdorferi; louse-borne relapsing fever is caused by B. recurrentis.
Purulent conjunctivitis in a newborn within the first days of life (ophthalmia neonatorum) can be caused by which organism acquired during birth?
Babies born to infected mothers can acquire gonococcal eye infection in the birth canal, which can cause blindness.
Acute epiglottitis in an unvaccinated young child is classically caused by:
Hib was the classic cause of epiglottitis and meningitis in young children before routine vaccination.
Healthy carriers harbour Neisseria meningitidis mainly in the:
Meningococci colonise the nasopharynx of carriers and spread by respiratory droplets.
Fulminant meningococcal septicaemia with shock and bleeding into the adrenal glands is known as:
Waterhouse-Friderichsen syndrome is adrenal haemorrhage with shock, classically in meningococcaemia.
Gonococcal infection of the cervix in women is important to screen for because it is often:
Many women with gonorrhoea have few or no symptoms, yet can develop pelvic inflammatory disease and infertility.
Methylene blue is used as an indicator in anaerobic jars. Under properly anaerobic conditions it becomes:
Methylene blue is blue when oxidised and turns colourless when reduced under anaerobic conditions.
In a tube of fluid thioglycollate medium, where do obligate anaerobes grow?
Oxygen is lowest at the bottom of thioglycollate broth, so obligate anaerobes grow there; obligate aerobes grow at the top.
Infant botulism has classically been linked to feeding babies:
Honey may contain C. botulinum spores, which germinate in the infant gut; it should not be given to babies under one year.