Microbiology Flashcards
1
Q
What is the MIC ?
A
Minimum concentration of antibiotic that can inhibit visible growth of a bacteria.
2
Q
Indifference in Micro means what?
A
One agent added makes no difference to another.
3
Q
How is synergism clinically relevant in relation to antibiotics?
A
B-lactam and aminoglycoside combination to treat endocarditis.
4
Q
What is the cell wall in bacteria made from?
A
Peptidoglycan.
5
Q
What is peptidoglycan made from?
A
NAG and NAM (muranic acid and glucosamine)
6
Q
Which two antibiotic groups are effective against cell walls?
A
B-lactams and Glycopeptides
7
Q
Which were the first true antibiotics in practice?
A
Penicillins (beta lactams)
8
Q
Four groups of B-lactams?
A
Penicillins
Carbopenems
Monobactams
Cephalasporins
9
Q
Name the only monobactam?
A
Aztreonam
10
Q
Give an example of a cephalasporin antibiotic?
A
Cefuroxime
11
Q
What is the spectrum of Ceph antibiotics?
A
Broad
12
Q
Monobactams are effective against Gram +ve or -ve
A
-ve
13
Q
Main glycopeptides in use?
A
Vancomycin and teicoplanin
14
Q
How do glycopeptides work?
A
Large molecules that bind directly to NAM
15
Q
Glycopeptides are only useful for gram positive or negative?
A
Positive, cannot bind to negative
16
Q
Bacteria have what sub units to make what unit?
A
30s and 50s =70s
17
Q
Gentamicin is an example of what type of antibiotic?
A
Aminoglycoside - gram neg
18
Q
How do aminoglycosides work ?
A
Bind to 30s ribosome (protein synthesis)
19
Q
Main side effect of gentamicin?
A
Nephrotoxicity
20
Q
Macrolide antibiotics?
A
Erythromycin and clarithromycin
21
Q
Action of macrolide antibiotics.
A
Protein synthesis
22
Q
Main lincosamide antibiotic is ?
A
Clindamycin
23
Q
Why might clarithromycin be used instead of erythromycin?
A
Less side effects
24
Q
Tetracycline is what class?
A
Protein synthesis
25
Main oxazalizonid?
Linezolid
26
Action of oxazalizonid?
Protein synthesis inhibitor - gram +ve
27
Mupirocin and fusidic acid?
Protein inhibitor
28
Trimethoprim and sulfonamides action?
Folate inhibition (DNA inhibitor)
29
Ciprofloxacin belongs to which antibiotic group?
Quinolones
30
May cause steven johnsons syndrome?
Co-trimoxazole
31
Quinolones and fluoroquino mechanisms?
DNA inhibitor
32
RNA synthesis inhibitor ?
Rifampicin
33
Which antibiotic never used alone?
Rifampicin -in TB
34
Colistin and daptomycin have mechanisms f action on?
Plasma membrane - Gram neg
35
Cyclic lipopeptides?
Colistin and daptomycin
36
Aminoglycosides?
Renal problems, ototoxicity, drug monitoring needed
37
Betalactam side effects?
Allergy main problem
38
Linezolid side effect?
Bone marrow suppression
39
Drugs considered safe in non severe penicillin allergy?
Cephalosporins and carbapenems
40
Drug considered safe in all penicillin allergy?
Aztreonam
41
Aztreonam lacks what nucleus type?
Bicyclic
42
What is the number for the c diff strain that is very severe?
027
43
Co-amoxi
Cephalasporin
Clindamycin
Ciprofloxacin Pre- dispose what?
C-diff
44
ESBL stands for what in micro?
Extended spectrum beta lactamase producing enterococciae
45
What is clinical resistance?
Organism is very susceptible in vitro but in vivo they are resistant.
46
Why is gram neg resistant to vanco?
Has an impermeable membrane
47
Why can gentamicin not treat anaerobic bacteria?
It depends on 02 uptake for its mechanism
48
How might flucloxacillin become resistant to MRSA?
Penicillin binding protein changes
49
VRE is caused by bacteria doing what?
Making different cell wall repeats in gram positive 1000 times less able to bind
50
Main antibiotics and other medicine to suscept to efflux?
Gram neg and triazoles!
51
How is horizontal transfer of resistance facilitated between bacteria?
Transposons and integrons - often a "cassette" of genes
52
Vertical resistance occurs how?
Through daughter cells at division
53
Parasitism means what?
Parasite always derives benefit host gets nothing and suffers injury!
54
Commensalism means?
Parasite only derives benefit, but the host does not sustain injury
55
What is the definitive host of a parasite?
Where the parasite reproduces or harbours adults
56
Intermediate host of parasite?
Asexual stages or larvae
57
Paratenic host is?
Where parasite remains viable but does not develop further
58
What is a helminth?
Worm
59
Cestode is what?
Tape worm
60
Trematode is what?
Flat worm
61
What is ascaris lumbicoides?
Intestinal round worm
62
Peak prevalence of ascariasis?
3-8yrs
63
How is ascaris transmitted?
Faecal oral - direct host
64
What is loefflers syndrome?
Migration of ascaris to lungs
65
Treatment of ascaris?
Albendazole (stops glucose absorption of worm)
66
Schistosomiasis is what type of worm?
Flat worm
67
What is bilharzia disease?
Schistosomiasis
68
What is the intermediate host for shistosomiasis?
Snails (fresh water)
69
Swimmers itch associated with what parasite?
Schistosomiasis
70
Treatment for schistosomiasis?
Praziquantel
71
Hydatid disease is caused by what?
Echinococcus (Tape worm)
72
humans are accidental hosts in what disease?
Hydatid (intermediate)
73
Where are most cysts found in hydatid disease?
Liver
74
What is the vector for malaria?
Anopheles Mosquito
75
Fever with malaria falciparum occurs when?
Alternative days
76
Returning traveller + fever =
Malaria until proven otherwise
77
What does cryptosporidium cause?
Diarrhoeal
78
Spread of cryptosporidium?
Faecal oral
79
Incubation of cryptosporidium?
2-10 days usually 7
80
Diagnosis of cryptosporidium?
Acid fast staining oocytes
81
Antiprotozoal drugs?
Metronidazole, pentamidine, nitazoxanide
| pyrimethamine
82
Anti worm/helminthic drugs?
Albendazole, mebendazole, ivermectin, praziquantel
83
approx worldwide infection of HIV?
35M
84
Pathogenesis of HIV?
Big burst of HIV, then control, then a latency and then CD4 count starts to fall off = AIDS
85
Acute viral infections?
Flu, Measles, Mumps, Hep A
86
What type of viruses tend to be acute? DNA? RNA? Retro?
RNA usually
87
Chronic viral is split into two?
Latent and persistent
| Herpes CMV / HIV (RNA virus but is reverse transcripted)
88
RNA to DNA viruses are also know as what?
Retroviruses
89
What was AZT originally going to be used for?
Anti-cancer
90
What type of drug is AZT?
NRTI - Nucleoside Reverse Transcriptase Inhibitor
91
Pyrimidine analogue HIV medicines?
Thymidine = zidovudine
Cytosine = Lamivudine
92
Purine analogue HIV medicines?
Abacavir and Tenofovir
93
Drugs that can treat Hep B as well as HIV?
Lamivudine and Tenofovir
94
Examples of protesase inhibitor?
Saquinavir
| Ritonavir = boost level of other Inhibitors
95
Fusion inhibitor - HIV?
Enfuviritide
96
Integrase inhibitor HIV?
Raltegravir
97
Chemokine receptor antagonist HIV?
Maraviroc
98
HAART consists of what 3 medicine combinations usually?
2NRTIs + 1 NNRTI
| 2NRTIs + 1 Boosted PI
99
Examples of NNRTI's?
nevirapine, efavirenz
100
M184V mutation makes resistant to what HIV drug?
lamivudine
101
Aciclovir is useful to treat what?
Herpes simplex
102
What is drug of choice for CMV?
Ganciclovir
103
Oseltamivir also known as what?
Tamiflu
104
Two forms of pathogenic fungi?
Yeast or filamentous
105
Pneumocystic jiroveci causes what?
Pneumonia in immunocompromised = fungal
106
Cell membrane of a fungus?
Ergosterol
107
Cell wall of fungus?
B -1,3-glucan
108
Ergosterol can be attacked by what?
Squalene epoxidase
| Lanosterol 14a demethylase
109
What does nystatin and amphotericin b act on?
Ergosterol
110
Amphotericin B and nystatin are what type of fungal medicine?
Polyene
111
Amphotericin B side effects?
Nephrotoxicity and allergy
112
Amphotericin B is only formed as what now?
Liposomal (stops kidney cell toxicity)
113
What is the only Allyamine?
Terbinafine
114
How does terbinafine work?
Targets squalene, thus ergosterol Toxic to liver!
115
what do azoles contain chemically?
5 membered ring synthetic
116
Imidizole and triazole = how many N atoms?
2 and 3
117
How do azoles work?
Inhibit lanosterol thus ergosterol
118
Fluconazole has no activity against what?
Aspergillus
119
Imidazole example?
Ketoconazole, miconazole, clotrimazole
120
Triazole examples?
Fluconazole
Itraconazole
Voriconazole
121
Problems with Azoles?
P=450 enzymes increased concentration
122
Fluconazole
Itra vori
posa Isav
(spectrum)?
Yeast F
Aspergillus and yeast I V
All yeast aspergillus and moulds PI
123
Echinocandins are analogous to what?
Beta lactam
124
Echinocandins work how?
Inhibit beta 1-3 glucan (= destroy cell wall)
125
Echinocandin example?
Anidulafungin (fungin on end)
126
Spectrum of echinocandin?
Misses cryptococcus
127
Echinocandins available how?
Parenteral
128
5-fluorocytosine was developed as what?
Anti cancer - has fungal activity
129
5- fluorocytosine can treat what?
Cryptococcal meningitis with amphoteracin
130
Notifiable diseases?
Meningitis, poliomyelitis, measles, mumps, rubella, smallpox
131
IgM present when in infection?
Acute
132
IgG present when?
Long term!
133
Immunoglobulin in breast milk?
IgA
134
Which virus causes measles?
Paramyxovirus
135
What is the infectivity of measles?
Start of first symptoms to 4 days after rash has resolved
136
Avg incubation of measles virus?
10-12 days
137
Measles also knows as what disease?
First
138
Three measles symptoms C's
Fever Cough conjunctivitis coryza (inflammed nose/mucous)
139
Spots in measles called?
Kopliks
140
Rare complication of measles?
SSPE Sub acute sclerosing panencephalitis Fatal
141
Chicken pox virus?
Varicella Zoster
142
Infectivity of chicken pox?
2 days before rash and until vesicles dry up
143
Age to treat chicken pox with antivirals?
>14yrs
144
Type of rash in chicken pox?
Centripetal, vesicular
145
Rubella known as what disease?
Third
146
Rubella cause by which virus?
Toga virus
147
Incubation of rubella?
14-21 days
148
Infective of rubella?
1 wekk before rash - 4 days after
149
Problems of rubella in pregnancy?
Congenital rubella syndrome
150
When most at risk of having rubella problems when pregnant?
first 9 weeks
151
What causes slapped cheek disease? also know as?
Parvovirus B19 known as fifth disease
152
When is peak of parvovirus?
Spring
153
What does respiratory syncytial virus cause?
Bronchiolitis
154
Diagnosis of rsv?
PCR on naso pharangeal secretions
155
Which virus is almost universal by age 5?
Metapneumovirus
156
Adenovirus often cause what?
Conjunctivitis, diarrhoea and URTI
157
Is paraflu treatable?
No, normal flu is
158
Diarrhoea causes?
Rota or noro virus
159
Is there a vaccine for rotavirus?
Yes!!
160
High fever and parotiditis?
Mumps
161
Mumps virus?
Paramyxoviridae
162
How does mumps present?
Earache initially, and ipsilateral parotid first High fevers!
163
What is sterilisation?
Complete removal and killing of all micro-organisms inc: vegetative and spores
164
What is disinfection?
Removal of sufficient organisms to make an item safe to use
165
Least hazardous way to decontaminate?
Heat
166
Greatest cause of death from what infection?
Pneumococcal
167
How long can maternal antibodies protect a child?
Up to 1 year
168
Using IgG can be effective for how long?
Only a few weeks to months (passive immunity)
169
Advantage of active immunity from vaccination?
No disease complications
170
What produces antibodies?
B lymphocytes
171
Clonal expansion is triggered by what?
Antigen binding non specifically to variable region of antibody
172
What are the live vaccines?
MMR,BCG, Yellow Fever and varicella
173
Inactivated vaccines?
Typhoid, pertussis and IPV
174
Flue vaccine made how?
Components of the organism
175
Diptheria and tetanus vaccine contains?
Inactivated toxin
176
Vaccines providing passive immunity?
Hep B, Botulism, Rabies
177
Nematodes what type of worm?
Round worms
178
Roundworms = two type?
intestinal and tissue
179
two trypanosomes?
leishmania and trypanasoma
180
Sporozoans include which parasites?
Malaria, cryptosporidium, toxoplasma etc
181
Which parasite is a flagellate?
Giardia lamblia
