MMSC 428 FINAL EXAM | QUESTIONS AND
ANSWERS | WITH COMPLETE SOLUTION
Staphylococcus aureus - -Correct Answer- -gram positive cocci in clusters
-facultative aerobe (prefers O2)
-halotonic
-ferment mannitol (yellow on MSA plate)
-catalase +
-*coagulase +*
-clumping factor +
-medium sized b-hemolytic white colonies
-serological tests for TSST-1 and DNA probes are the best diagnosis methods
-most clinically significant staphylococcus
-important cause of nosocomial infection
bordetella pertussis culture - -Correct Answer- -collect LRT sample
-transport media: regan low (RL) or amies charcoal media required
-media:bordet gengou, regan lowe or *BCYE* (used most)
,bordetella pertussis clinical manifestations - -Correct Answer- -pertussis:
whooping cough
-incubation: 4-21 days with no symptoms
-catarral: prodromal nonspecific symptoms of the common cold
-paroxysmal: exacerbation of symptoms when bacteria reaches the LRT and
infects ciliated cells and produces pertussin toxin that leads to fluid buildup in
lungs, fever, chills and bouts of productive coughing that last several minutes,
symptoms remain for several months
-convalescent: recovery from infection takes 2-5 weeks
-*treatments do not shorten the disease, they decrease the symptoms*
bordetella bronchiseptica - -Correct Answer- -gram negative bacilli
-mac +
-oxidase +
-*rapid urease + (strong and fast)*
-motile
-zoonosis
-causes kennel cough in dogs that can spread to humans and cause URT infection
(spreads to LRT infection in immunocompromised individuals)
brucella characteristics - -Correct Answer- -gram negative coccobacilli
-FIP of WBCs
-reportable disease
-potential bioterror agent
-slow grower (7-10 days)
-oxidase +
,-urease +
-SBA and BCYE +
-MTM +
-brucellosis (undulant/ malta fever): alternating very high and low fevers that
correspond with levels of brucella bacteria in the blood peaking and lowering
francisella tularensis - -Correct Answer- -tiny pleiomorphic gram negative bacilli
(do not gram stain well)
-fastidious, difficult to culture
-cystine or cystiene amino acids required
-grow at 35 C
-grow better with increased CO2
-SBA -
-chocolate, BCYE, MTM and glucose cysteine blood agar +
-medium sized white colonies
-slow growers (10-14 days)
-zoonosis that spreads from squirrels/ rabbits to humans via tick vectors
-higher risk for people who spend time in the woods (exposed to ticks)
-DFA, PCR or 4 fold rise in IgM titer are diagnostic
-causes tularemia
francisella tularensis clinical manifestations - -Correct Answer- -zoonosis spread
from squirrels/ rabbits to humans via tick vectors
-tularemia: bacteria in the blood leads to many different clinical manifestations
, -ulceroglandular:most common form of tularemia, lesions on skin form around
the area of the tick bite, bacteria infects regional lymph glands and causes
inflammation
-glandular infection: no visible skin lesion, just formation of infected buboes
-oculoglandular infection: bacteria infects eyes and leads to inflammation of eyes
and lymph glands of the face
-pulmonary/ pneumonic infection: bacteria is inhaled and infects lungs
-typhoidal infection: symptoms resemble typhoid fever (high fever, chills,
headache, mental confusion, rash), no glandular involvement
-oropharyngeal/ GI: most rare infection, ingestion of bacteria causes pharyngitis,
swollen cervical lymph nodes and GI irritation
gardnerella vaginalis - -Correct Answer- -gram variable bacilli, decolorize easily
-normal biota of vagina
-indicator organism for bacterial vaginosis
-fastidious, grows better in CO2
-slow grower
-B-hemolytic
-identified using nugent scoring system (amsel criteria are no longer used due to
subjective scoring)
-hippurate hydrolysis +
-starch hydrolysis +
gardnerella vaginalis clinical manifestations - -Correct Answer- -bacterial
vaginosis: lactobacillus in the vagina decrease, allowing other bacteria to
overpopulate and cause discharge with foul odor and mild itch
ANSWERS | WITH COMPLETE SOLUTION
Staphylococcus aureus - -Correct Answer- -gram positive cocci in clusters
-facultative aerobe (prefers O2)
-halotonic
-ferment mannitol (yellow on MSA plate)
-catalase +
-*coagulase +*
-clumping factor +
-medium sized b-hemolytic white colonies
-serological tests for TSST-1 and DNA probes are the best diagnosis methods
-most clinically significant staphylococcus
-important cause of nosocomial infection
bordetella pertussis culture - -Correct Answer- -collect LRT sample
-transport media: regan low (RL) or amies charcoal media required
-media:bordet gengou, regan lowe or *BCYE* (used most)
,bordetella pertussis clinical manifestations - -Correct Answer- -pertussis:
whooping cough
-incubation: 4-21 days with no symptoms
-catarral: prodromal nonspecific symptoms of the common cold
-paroxysmal: exacerbation of symptoms when bacteria reaches the LRT and
infects ciliated cells and produces pertussin toxin that leads to fluid buildup in
lungs, fever, chills and bouts of productive coughing that last several minutes,
symptoms remain for several months
-convalescent: recovery from infection takes 2-5 weeks
-*treatments do not shorten the disease, they decrease the symptoms*
bordetella bronchiseptica - -Correct Answer- -gram negative bacilli
-mac +
-oxidase +
-*rapid urease + (strong and fast)*
-motile
-zoonosis
-causes kennel cough in dogs that can spread to humans and cause URT infection
(spreads to LRT infection in immunocompromised individuals)
brucella characteristics - -Correct Answer- -gram negative coccobacilli
-FIP of WBCs
-reportable disease
-potential bioterror agent
-slow grower (7-10 days)
-oxidase +
,-urease +
-SBA and BCYE +
-MTM +
-brucellosis (undulant/ malta fever): alternating very high and low fevers that
correspond with levels of brucella bacteria in the blood peaking and lowering
francisella tularensis - -Correct Answer- -tiny pleiomorphic gram negative bacilli
(do not gram stain well)
-fastidious, difficult to culture
-cystine or cystiene amino acids required
-grow at 35 C
-grow better with increased CO2
-SBA -
-chocolate, BCYE, MTM and glucose cysteine blood agar +
-medium sized white colonies
-slow growers (10-14 days)
-zoonosis that spreads from squirrels/ rabbits to humans via tick vectors
-higher risk for people who spend time in the woods (exposed to ticks)
-DFA, PCR or 4 fold rise in IgM titer are diagnostic
-causes tularemia
francisella tularensis clinical manifestations - -Correct Answer- -zoonosis spread
from squirrels/ rabbits to humans via tick vectors
-tularemia: bacteria in the blood leads to many different clinical manifestations
, -ulceroglandular:most common form of tularemia, lesions on skin form around
the area of the tick bite, bacteria infects regional lymph glands and causes
inflammation
-glandular infection: no visible skin lesion, just formation of infected buboes
-oculoglandular infection: bacteria infects eyes and leads to inflammation of eyes
and lymph glands of the face
-pulmonary/ pneumonic infection: bacteria is inhaled and infects lungs
-typhoidal infection: symptoms resemble typhoid fever (high fever, chills,
headache, mental confusion, rash), no glandular involvement
-oropharyngeal/ GI: most rare infection, ingestion of bacteria causes pharyngitis,
swollen cervical lymph nodes and GI irritation
gardnerella vaginalis - -Correct Answer- -gram variable bacilli, decolorize easily
-normal biota of vagina
-indicator organism for bacterial vaginosis
-fastidious, grows better in CO2
-slow grower
-B-hemolytic
-identified using nugent scoring system (amsel criteria are no longer used due to
subjective scoring)
-hippurate hydrolysis +
-starch hydrolysis +
gardnerella vaginalis clinical manifestations - -Correct Answer- -bacterial
vaginosis: lactobacillus in the vagina decrease, allowing other bacteria to
overpopulate and cause discharge with foul odor and mild itch
