aerobic gram positive rods Flashcards

1
Q

are bacillus aerobic or anaerobic

A

aerobic

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2
Q

are bacillus gram positive or negative? what shape

A

gram positive rods

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3
Q

are bacillus spore producing

A

yes

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4
Q

why can bacillus spores be used for quality control of sterilisation procedures eg autoclave spore strips

A

very resistant towards drying, heat

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5
Q

what kind of symptoms (system) do bacillus cause and how does it cause it

A

gastrointestinal symptoms, caused by production of toxins

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6
Q

microscopy shape of bacillus

A

box shaped, occur in chains

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7
Q

what bacteria species is anthrax

A

bacillus

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8
Q

are anthrax spore producing

A

yes

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9
Q

where can anthrax spores be found

A

extremely tough spores, may be carried on animal hides, bone fertilisers. uncommon in major cities, usually rural areas. patient may have travel history or exposure to animals in eg mongolia

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10
Q

what bacillus is suitable for biological warfare

A

bacillus antracis ie anthrax

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11
Q

how does inhalation of anthrax differ from ingestion of anthrax

A

symptoms dependent on infection route. inhalation cause pulmonary anthrax, ingestion cause gastrointestinal anthrax

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12
Q

why is b anthracis suitable to be used for bioterrorism

A

aerosol delivery for effective dissemination

spore-forming hence difficult to eradicate

use drug resistant strains

high mortality rate

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13
Q

is lactobacillus gram positive or negative, aerobic or anaerobic, what is its shape

A

microaerophilic gram positive rod

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14
Q

what kind of environment does lactobacillus prefer to grow in

A

lactobacillus is acidogenic, prefer to grow in acidic environment. it is aciduric and produces acid to make environment for favourable for itself.

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15
Q

what bacteria can be used as probiotics

A

lactobacillus

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16
Q

where is lactobacillus part of the normal flora

A

gastrointestinal tract and female genital tract

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17
Q

what is role of lactobacillus in development of caries

A

progression of deep enamel lesions, pioneer organism on advancing front

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18
Q

is corynebacterium diphtheriae gram negative or gram positive

A

gram positive

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19
Q

is corynebacterium diphtheriae aerobic or anaerobic

A

aerobic

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20
Q

where is corynebacterium diphtheriae part of the normal flora

A

upper respiratory tract

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21
Q

what kind of upper respiratory infections can corynebacterium diphtheriae cause

A

patients mainly asymptomatic carriers. can cause throat infection under certain conditions. nasal, laryngeal, tracheal sites may also be infected

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22
Q

majority of corynebacterium diphtheriae is not pathogenic. how do the pathogenic strains cause disease

A

diphteria toxin

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23
Q

what does corynebacterium diphtheriae vaccine target

A

diphteria toxin

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24
Q

what kind of infection does toxigenic corynebacterium diphtheriae usually cause

A

skin infection and upper respiratory tract infection

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25
what kind of infection does non toxigenic corynebacterium diphtheriae usually cause
skin infections
26
what are symptoms of corynebacterium diphtheriae infection
sore throat, malaise, fever, airway obstruction because oropharyngeal tissues slough off to form pseudomembrane that blocks airway, palatal paralysis, neuropathy, myocarditis, bull neck
27
what bacteria causes "bull neck"
corynebacterium diphtheriae
28
how is classical diphteria diagnosed
clinically. begin treatment before microbiological confirmation due to severity of disease
29
how to test for corynebacterium diphtheriae toxin production
PCR
30
how is corynebacterium diphtheriae treated
antiserum (antitoxin) antibiotics: penicillin, erythromycin patient should be isolated
31
how can spread of corynebacterium diphtheriae be prevented
toxoid vaccine and antibiotics given to patient and contacts (antibiotic prophylaxis)
32
describe listeria monocytogenes (gram, aerobic/an, shape)
gram positive aerobic short rod, slender
33
What temperatures is listeria monocytogenes able to grow at
able to grow even at 4ºC hence can continue to grow even if food is refrigerated
34
how is listeria monocytogenes transmitted
foodborne, causing gastroenteritis outbreaks
35
clinical presentation of listeria monocytogenes
flu like illness in pregnant women still born baby, baby with disseminated infection or meningitis after delivery invasive infections in people of extreme ages and in immunocompromised
36
what go beaded gram positive rods appear as microscopically and why
filamentous, branching, string of pearls appearance due to uneven uptake of stan
37
what kind of bacteria is actinomyces
gram positive facultative anaerobe
38
what kind of bacteria is nocardia spp.
grampositive, aerobic actinomyces
39
what bacteria is modified acid fast positive
nocardia spp. takes up acid fast stain to some degree but not as much as mycobacterium
40
who does nocardia spp. usually infect
immunocompromised patients
41
what are the clinical presentations of nocardiosis
pulmonary infections, brain abscesses, skin/soft tissue infection
42
how to treat nocardia spp
trimethoprim-sulphamethoxazole ie cotrimoxazole. give combinations of more than one antibiotic based on susceptibility testing. treat for more then one month due to concern of relapse
43
does actinomyces cause acute or chronic infections
chronic infections, require long term treatment to prevent recurrence
44
what bacteria can cause chronic canaliculitis
actinomyces
45
how to treat actinomyces
surgical debridement with antibiotics
46
what shape is mycobacterium
rod shaped
47
is mycobacterium gram positive or negative
gram positive
48
is mycobacterium aerobic or anaerobic
aerobic
49
what bacteria appears pink on ziehl neelson stain and why
mycobacterium because it is acid fast bacilli and contains mycolic acid in cell wall
50
what are the main pathogenic strains of mycobacterium. where are non pathogenic strains found
m tuberculosis and m leprae all other species ala atypical mycobacteria/non tuberculous mycobacteria are environmental especially where there is water/moisture. tend to not be as pathogenic.
51
how is tuberculosis transmitted and where does it usually infect
airborne via human to human spread. NOT DROPLET TRANSMISSION!! hence must use n95 pulmonary infection
52
what percentage of patients gets infected following exposure to m tuberculosis
10%
53
what are the classical tb symptoms
fever and night sweats, cough with sputum production, weight loss
54
what type of necrosis is characteristic of tb infection
caseous necrosis
55
what happens in primary pulmonary tb
ghon focus: spreads to regional lymph nodes, lymph nodes enlarge granuloma formation in attempt to contatin infection caseous necrosis
56
what happens when tb progresses from primary stage
progression of primary lung lesion, pleural effusion bacteremia. disseminated in blood stream (miliary infection)
57
what can happen as a result of miliary infection
disseminated tb infection in blood stream can cause organ specific infection mimicking cancer, meningitis, genitourinary tract infection including kidneys
58
what are the clinical manifestations of oral tuberculosis
``` non healing chronic ulcers local lymph node enlargement jaw osteomyelitis inflammation abscess ```
59
how to diagnose tb
biopsy oral lesion and do afb microscopy and culture ``` histology for tissue/bopsy specimens afb smear (microscopy), afb culture, molecular testing ```
60
what is the downside to afb smear in trying to diagnose mycobacterium tb infection
unable to differentiate between tb and non tb mycobacteria
61
how long does m tuberculosis culture take to grow
6-8 weeks
62
what is lowenstein jensen media used for
tuberculosis
63
how is tuberculosis cultured nowadays
MGIT system, liquid media automated reading, more sensitive than lowenstein jensen solid media, faster positive results
64
what is the advantage of using molecular methods to diagnose m tuberculosis
pcr gives same day results and able to differentiate m tuberculosis from other mycobacterium and able to detect rpob gene coding from rifampicin resistance
65
how are patients treated for tb
if not resistant to rifampicin, multidrug therapy with rifampicin to avoid development of rifampicin resistant TB. extended treatment for 6 months or more
66
what is time period for statutory notification of tb infection
72 hours
67
what is the contact screening procedure for tb
tuberculin skin testing, quantiferon gold, t spot, x ray to exclude active disease
68
how are patients with pan sensitive tuberculosis dealt with
isolated in negative pressure room until deemed non infectious they become non infectious within 2 weeks of treatment
69
what does bcg vaccine do
reduce risk of serioud tb eg meningitis tb but does not prevent you from getting infection. limited efficacy ie previously vaccinated patient can get active tb
70
what is leprosy caused by
mycobacterium leprae
71
compare grwoth rates of m tuberculosis, slow growing atypical mycobacterium, rapidly growing atypical mycobacterium
tb 2-3 weeks slow 4-6 weeks rapid within 1 week
72
4 different types of clinical presentation of non tuberculosis mycobacterium infection (more common in immunocompromised)
lymphadenitis: single node in neck of young child who may not be immunocompromised. tb can also present this way. biopsy/sample lymph node skin infection: direct inoculation. rapid growing hospital acquired eg post injection. slow growing community acquired eg traumatic inoculation, get cut on the beach pulmonary disease: patient has pre existing chest disease eg chronic cough, all other pathologies must be excluded as NTM lung infection is rare disseminated infection: chronic, in immunocompromised patients esp m. avium complex. prolonged treatment
73
why is repeated isolation of same non tuberculosis mycobacterium necessary to diagnose pulmonary disease caused by atypical mycobacteria
atypical mycobacteria are environmental bacteria hence single positive cultures may be due to contamination of sample. require multiple cultures taken over several days all yielding positive results should also get consistent clinical and radiological features
74
how to treat non tb mycobacterium infection
surgical debridement of infective focus and antibiotic treatment m. avium: calrithromycin, rifampicin, ethambutol m kansasii: rifampicin, ethambutol, isoniazid high rates of recurrence in pulmonary infections esp underlying lung disease, patient may not be able to get off treatment or may require baseline antibiotics