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Flashcards in Microbiology Deck (260)
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121

What tests are done on oxidase negative enterobacteriacae?

biochemical identification (API strip) and sensitivity strips

122

What test is done on lactose fermenting bacteria?

biochemical identification (API strip) and sensitivity strips

123

Which is the least selective agar?

blood agar so good for many bacteria

124

What is chocolate agar?

blood agar heated to 80c for 5 minutes to release nutrients into agar - means certain organisms dont grow as well

125

What is MacConkey agar used for?

to grow and differentiate gram negative bacilli with bile salts to inhibit positive, contains lactose and neutral red dye to strain fermenting and non fermenting

126

What is gonococcus agar used for?

contains growth factors to promote Neisseria and has antibiotics and antifungal agents to inhibit other growth

127

What is CLED agar used for?

non inhibitory growth medium to differentiate microoganisms in urine, classifying fermenting and non fermenting

128

What is Sabouraud's agar used for?

cultures fungi and uses bacteria with antibiotics

129

What is XLD agar used for?

very selective for salmonella and shigella with phenol red indicator so bright red at pH 7.4 and then turns yello

130

How can pathogens be distinguished from norma flora?

restrict it using plates in different atmospheres and temperatures with range of nutrients and using selective media

131

What does shigella cause?

4 types that lead to diarrhea

132

What does salmonella cause?

gastroenteritis and enteric fever and bacteraemia

133

What is the most common faculative anaerobe in the gut?

E.coli

134

What does E.coli cause?

cystitis, UTI, wounds infections

135

What the main forms of Neisseria?

Neisseria meningitidis and Neisseria gonorrhoea

136

What are the main bacteria that cause UTI?

E coli, klebsiella, pseudomonas

137

What is a common gram positive bacilli that is in neonates and elderly?

Listeria monocytogenes

138

Are staphylococci and streptococci chains or clusters?

staph = clusters
strep = chains

139

What is another name for s.pyogenes?

group A streptococci

140

What organism is oxidase test negative and causes dysentry?

shigellosis

141

What are the 2 methods of viral diagnosis?

virus detection or serology

142

What methods are used for virus detection?

electron microscopy, cytopathic effect and PCR (preferred)

143

What is and advantage and disadvantage of ECM and cytopathic effect for virus detection?

time consuming and a lot of effort and cannot be be used in modern labs, but are good for new viruses

144

What happens in PCR?

enzymes unzip DNA and RNA chains, make complementary copies with flourescent tags, and is then replicated and then the DNA can be measured by the flourescence which is only activated when bound to the chain

145

Advantages and disadvantages of PCR in virus detection?

very sensitive and quick, but liable to contamination and false positives, so you must have suspected the virus in the first place, making it difficult for novel viruses

146

What is serology?

the study and detection of antibody responses in the serum

147

What antibodies are seen after an acute infection??

IgM for up to 12 weeks after, then IgG later and is responsible for immunity

148

What different serology techniques are there?

complement fixation test, haemagglutination (inhibition), enzyme linked immunosorbent assay (ELISA), radioimmuo assay, immunofluoresence

149

Common enteroviruses?

rhinovirus, echovirus, coxsackie a and b

150

Common respiratory viruses?

influenza A/B, parainfluenza, RSV, coronavirus, rhinovirus, measle, rubella, metapneumonvirus, parvovirus, adenovirus