Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Flash Facts > microbiology 1 > Flashcards

microbiology 1 Flashcards

(93 cards)

Start Studying
1
Q

enterococcal endocarditis is seen after

A

GIT or GUT instrumentation or catherisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the characteristics of enterococci

A

Bowel bacteria— hence can grow in hypertonic saline and bile.
Gram positive cocci
Strepto grp– hence if catalase negative.
Simple bacteria causing no hemolysis– gamma hemolysis.
PYR test positive — red colour

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

difference between enterococci and S bovis/ gallolyticus

A

Both are non hemolytic / gamma hemolysis
and both grow in bile
But PYR positive and growth in hypertonic saline is shown only by enterococci
Gallolyticus – does not grow in hypertonic saline and is PYR negative – does not show red colour.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the principle of PYR test

A

detects enz pyroli-donyl arylamidase produced by bacteria.

Product Beta naphthalamine give red colour on reacting with reagent in test.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

uses of PYR tests

A
  1. distinguishes between enterococci from Strepto galloyticus
  2. Distinguishes E coli from other indole positive, lactose positive gram negative bacteria
  3. Distinguishes GABHS (S pyogenes) from GB-BHS (S galactae)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Importance of enterococci

A

30 % nosocomial endocarditis is from enterococci.
colonoscopy, cystoscopy, vaginal instrumentation, obstretics, pelvic surgery all are predisposing factors.

Most common cause of UTI
Local perineal and abdominal wound infection.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Problem with enterococcal infection

A

resistant to most antibiotics, difficult to treat.
Cell wall agent like ampicillin +Aminoglycosides are together given.
Largely resistant to these two medications also.
Vancomycin and linezolid resistance is also seen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

dental extraction endocarditis points to remember are

A

occurs in abnormal heart valves.

caused by VGS— viridans group streptococci

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is bile solubility tests

A

To differentiate streptococcus pneumoniae from alpha hemolytic streptococci
when bacteria is placed in a solution of bile salts, surface tension is reduced, autolytic enz within the bacteria is released and undergoes autolysis.
That is within few days broth gets cleared. ie bacteria is soluble (dies) in bile salts.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

characteristics of VGS viridans (tooth decays)
ie Str. Mutans
Str. Sanguinis

A

mouth commensal– no growth in bile or hypertonic saline.
bile insoluble. Does not undergo cell lysis
ability to utilise sucrose and produce dextran (insoluble extracellular sugar polysaccharide)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

which bacteria can produce dextran from sucrose

A

VGS viridans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does VGS viridans cause tooth decay and nosocomial endocarditis after dental extraction

A

VGS can produce extracellular insoluble sugar – dextran from sucrose which helps in adherence.

ADHERE to TOOTH ENAMEL
ADHERE to FIBRIN-PLATELET aggregates on damaged heart.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

pseudomembranous pharyngitis and cervical lymphadenopathy, myocarditis, heart failure and neurotoxicity is seen in

A

Diphtheria.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Pathogenesis of diphtheria

A

DT toxin – irreversibly inhibits ADP ribosylation of Elogation factor 2 (EF 2)– inhibits host protein synthesis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

treatment of diphtheria

A

1– Antitoxin– ie preformed neutralising antibodies that inactivate toxin DT.
Because it cannot inhibit the toxin that has already entered cell. It should be administered ASAP.

2nd line –antibiotics Beta lactam/aminoglycoside (b lactam/ erythromycin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Organism for epiglottitis

A

H influenza esp in unvaccinated ppl

Drooling of saliva, stridor, tripod position to feel better.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Interferon gamma is critical in immunity against —- and —

A

viruses and intracellular bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Interferon gamma functions 3 things

A
  1. Activates macrophages
  2. Increases MHC expression by macophages
  3. Activates TH1 helper T cells.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is IGRA test

A

Interferon Gamma release Assay… detects latent TB.

Measures Cell M Immunity. Ie response of T cell to release Interferon Gamma when cultured with mycobacterial antigens.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

cause of severe sepsis in asplenic pts

A

because 50 percent of bodys total antibody response comes from splenic B cells.
These splenic opsonising antibodies are particular important for encapsulated organism. Because capsulated organisms resists phagocytosis by neutophils and bacteria. They need opsonisation to be killed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Asplenic pts needs vaccination against

A

NHS ::
Neisseria meningitis
Hemophilus influenza
Strepto Pneumoniae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

endocarditis on Right heart

A

IV drug —staph aureus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Immunity against giardiasis is from

A

secretory Ig A and helper T cells.

IgA binds to its infective form trophozoites not allowing it to bind to mucosa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what conditions predisposes to chronic giardiasis

A

Selective IgA deficiency
X linked Agammaglobulinema
CVID combined variable immunodeficiency.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Which intestinal pathogens are intracellular
Cryptosporidium parvum | Toxoplasma gondii
26
Ceftriaxone/ cephalosporins bind to penicillin binding protein name ____ to cause cell wall instability.
Transpeptidase. | It is a normal enz of streptococci which functions to cross (trans) link peptidoglycans in cell wall.
27
porin mutations are implicated in
antibiotic resistance in gram negative organisms. | They allow antibiotics to diffuse into the cell from outer membrane to inside.
28
mechanism of ceftriaxone resistance
structural changes in penicillin binding proteins is one of many mechanisms of ceftriaxone resistance.
29
why is there no vaccine against Neisseria gonococcal bacteria. and it is important to treat partner
Because antibody response is against gonococcol pili and Pili gene undergoes large amount of gene recombination giving rise to antigenic variation. Hence prior infection and antibodies do not offer immunity, treating partner is important no vaccine can be developed.
30
gonococcal antibiotic resistance is from
plasmid conjugation.
31
where does the fungi grow in mucormycosis
Mucor, rhizopus and absidia species grow in the walls of blood vessels of paranasal sinuses. Causes ischemic necrosis and black eschar
32
Morphology of mucormycosis fungi
They exists as mold form only. | Aseptate wide 90 degree branching mold.
33
single stranded RNA virus leading to loss of brain mass and subcortical calcifications in brain
ZIKA virus. Transmitted by Aedes bite. Disrupts fetal neural progenitor cells, migration and neural development affected. Leads to fetal demise. Surviving babies are given supportive treatment only.
34
Common cause of aseptic meningitis
Enterovirus (Most common) Arbovirus HSV 2
35
What diseases vibrio vulnificus can cause
Like other vibrio-- -watery diarrhoea esp severe in chronic liver disease patient Wound infections Severe rapid onset sepsis
36
dipicolinic acid
content of spore
37
who can form spore
only gram positive bacteria
38
specific chemical of capsule of B anthracis
B anthracis capsule is made of poly D glutamate.
39
function of capsule and slime layer
capsule prevents phagocytosis | Slime layer helps adherence to plastic or foreign non living things like catheter
40
Where is endotoxin situated
In outer membrane of gram Negative organisms
41
what three chemical together form endotoxin
LIPID A - Induces INF and IL1 O specific polysaccharide - ANTIGEN O Core oligosaccharide
42
Only one structure unique to gram Positive cell wall
Lipo teichoic acid
43
THree structure unique to gram negative organism
Periplasmic space where beta lactamase enz is located. | Outer membrane which contains PORINS and ENDOTOXIN
44
Cell wall is cross linked by which enz
transpeptidase. | Site of ceftriaxone action.
45
Immune response in GM negative is from endotoxin which stimulated TNF and IL 1 release. What part of gram positive bacteria is responsible for release of these
Lipoteichoic acid.
46
PBP and certain transport enz are located in which part of cell
cytoplasmic membrane
47
ZN stain organisms
Mycobacteria and nocardia | Cryptosporidium ova-- DIarrhoea in HIV
48
examples of aerobic bacteria --- use oxygen for ATP generation
Mycobacteria and nocardia Pseudomonas aeruginosa Bordetella pertusis
49
THree prime effects of endotoxin
Macrophage activation by TLR 4 and CD14 Complement activation (C3a and C5a) DIC causative-- tissue factor 12 activation
50
Macrophage activation in endotoxic shock is because of release of what substances from macrophage
IL1 and IL 6 ---- fever TNF alpha--------Fever and hypotension Nitric oxide- vasodilator---- hypotension.
51
biofilm producing bacteria (strep/ staph/ H infl/Pseu) all most imp organism
VGS (dental plaque and IE) Staph epidermidis-- normal flora of skin and forms biofilm of catheters and prosthesis Unencapsulated non typeable H influenza- Otitis media PSeudomonas -- LEns keratitis, cystic fibrosis cavity lining and ventilator associated pneumonia
52
Autoclave settings
121 degree celsius | 15 min to kill spores.
53
Two main opsonins for bacteria
C3b and IgG
54
name the three conjugated vaccine. Why are they conjugated
COnjugated vaccines : when a carrier protein is added to antigen which is a capsular polysaccharide. Polysaccharide alone cannot mount T cell immune response and class switching. Hence encapsulated organism vaccines are conjugated vaccines. Remember the asplenic vaccines -- S. Pneumoniae, N meningitis, H influence Type B.
55
Name the pneumococcal vaccines
There are two available. Conjugated and unconjugated with protein Conjugated is called PCV 13 Unconjugated is called PPSV 23-pneumococcal PS polysacharide v- vaccine.
56
basic Enzymes tests in microbiology
Catalase Coagulase- converts fibrinogen to fibrin Urease- urea to ammonia Oxidase- adds hydrogen to oxygen producing Water or H2o2
57
Enterococci are PYR
Positive
58
GAS s pyogenes are PYR
positive
59
GBS S agalactiae is PYR
Negative
60
Hippurate test positive organisms
Gardenella Campylobacter Listeria S agalactiae (use this test to differentiate with S pyogenes sometimes)
61
Cryptococcus neoformans is a yeast causing Meningitis in HIV positive patients. Stain used is
Indian ink preparation. | Shows thick polysaccharide capsule
62
VZV immunity is primarily
Cell mediated immunity
63
chinese letter bacteria joined by V or Y shaped | Granules staining with aniline dyes (methylene blue, albright stain) at poles.
Corynebacterium diphtheria
64
growing hyphae are known as germ tubes. They are seen in
Candida albicans when they are inoculated into serum at 37 degree celsius 98.6 F for 3 hrs It is formation of true hyphae from yeast. On light Microscopy... candida appears as budding yeast with pseudohyphade. Only albicans when grown at particular temp shows true hyphae. and hence this test is used to differentiate candida albicans from other candidial species.
65
stains for cryptococcus neoformans
1. Methanamine silver stain -- identifies yeast form of cryptococcus-- round cells with narrow based budding 2. Indian iNk stain- thick halo of polysaccharide capsule 3. Mucicarmine stain--- red colour of capsule.
66
Only pathogenic fungus that has polysaccharide capsule
Cryptococcus neoformans.
67
Most common cause of bronchiolitis (wheezes and rales) in less than 2 year old
RSV
68
Intestinal ulcers with undermining edges (flask shaped) and has trophozoites
Entameba histolytica
69
two protiens that help entamoeba histolytic in invasion
enz-- proteases -- lyse host membranes and sec IgA Protein LECTIN helps in adhesion introduces amoebic PORIN and causes Contact dependent cytotoxicity.
70
OHIO and MISSISIPI river valleys
HISTOPLASMOSIS
71
causes of genital ulcer dieases
1. Herpes -- painful multiple vesicular ulcers 2. syphillis-- PAINLESS single non vesicular clean base heaped up margins with non tender rubbery nodes 3. Chancroid-- painful deep ulcers with pus and matted and suppurative nodes 4. Granuloma inguinale -- PAINLESS multiple SERPINGINOUS ulcers without nodes.
72
Granuloma inguinale is also known as ---- cause by organism ----
Granuloma inguinale is also known as DONOVANOSIS cause by organism KLEIBSELLA GRANULOMATOSIS
73
genital chancroid is caused by organism-----------
genital chancroid is caused by organism HEMOPHILUS DUCREYI
74
Presentation of Lymphogranuloma venerum and primary syphilis is same. Where is the difference in clincal characteristics
Both have single painless ulcer Ulcer in syphillis has heaped up margins nodes are painless in sypillis and painful in chlamydia
75
where do animals harbour leptospira
in proximal renal tubule and secrete them in urine
76
Flu like illness with lymphadenapathy, liver and renal failure and end organ damage with bilateral non inflammatory conjunctival suffusion is seen in
leptospirosis. | Bilateral conjunctival suffusion is an important diagnostic clue.
77
Donovan bodies and donovani bodies are different
DONOVAN -- kleibsella granulomatis-- granuloma inguinale. Rod shaped gram negative organism in macrophages DONOVANI-- amastigotes within macrophages-- leishmaniasis kala-azar
78
Asymmetric LMN type flaccid paralysis signs of meningitis ANd /or rash fever And / or parkinsons disease
west nile neuroinvasive disease. Bite of culex mosquitoes summer florida warm climates Intermediate host- birds
79
elevated erythrocytes with lymphocytic pleocytosis in CSF
herpes simplex encephalitis
80
filamentous gram positive anaerobic to microaerophilic organism responsible for causing dental caries and orofacial abscesses with draining sinuses
Actinomyces Dz is called actinomycosis. Multiple interconnected abscesses.
81
PID in a female patient with uterine IUD
pelvic actinomycosis
82
which cephalosporins are used for pseudomonas
3rd gen- ceftazidime | 4th gen-- cefepime
83
Bactrim-- TMP + SMX is used against which organisms
1. Pneumocystis jerovecii 2. Toxoplasma gondii 3. Stenotrophomonas Maltophilia 4. Nocardia.
84
Cold agglutinins which causes clumping of blood RBC when placed in ICE and then whn brought to room temp disappears is seen in which infection
Mycoplasma pneumoniae.
85
Cold agglutinins are formed in mycoplasma infection because
Adhesive protein L surface antigen leads to development of Ig M type antibodies Which are pentameric in form Cross react with antigens on the surface of RBC and in cold areas of body like periphery or pinna cause complement activation and intravascular hemolysis (Cf Ig G warm antibodies cause extravascular hemolysis)
86
diseases leading to formation of cold agglutinins
mycoplasma pneumoniae infection hematological malignancies Infectious mononucleosis EBV
87
High fever with relative bradycardia Cruise travel neuro and GI symptoms chest lung insterstitial patchy infiltrates Little or no micro-organisms on sputum only neutrophils hyponatremia
Legionella
88
Only pneumonia with hyponatremia
Legionella grows of BYCE medium urinary antigen testing positive.
89
what microbiology concept is seen as predisposing factor in ankylosing spondyltitis
ALTERED GUT MICROBIOME AND DEFECTS IN MUCOSAL BARRIER. induces Th1 and Th17 helper cells to release interleukin 17 this is due to altered antigen presentation which is due to HLA b27 genetics. IL 17 causes release of TNF alpha and prostaglandins causing systemic bony erosions and abnormal bone growth.
90
What drugs are used in treatment of anklyosing spondyltiis
It is IL-17 induced release of TNF alpha and PGs which is causing damage. Drugs like NSAIDS and antiTNF alpha are thus used.
91
Bacteria responsible for acute suppurative parotitis
Staph aureus | mixed oral anaerobes
92
Causative organism for cellulitis
NON PURULENT CELLULUTIS -- Beta hemolytic streptococci OF THESE GAS - S PYOGENES majorly responsible PURULENT CELLULITIS- pus- staph aureus (because of virulence factor-- kn as panton valentine leukocidin causes skin abscess)
93
aversion to smoking is caused by which viral infection
hepatitis A

Flash Facts (23 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions