Gram-positive Bacilli Flashcards
Classification of bacilli
Familybacillaceae Aerobic spore forming Gram positive B.anthracis B.cereus
Classification of gram positive bacilli
Endospore Formers:bacillus,clostridium Non formers:listeria,erysipelothrix Irregular shaped and staining properties : Corynebacterium Mycobacterium Actinomycetes No cardio
Bacillus anthrax
Non motile
Capsulated
Spores
Zoonotic
Diseases of anthrax
Inhalation(pulmonary anthrax) I :5% M:95%
Wool sorters disease
Pre treatment :duckering i.e treating with formaldehyde
D/s:mediastinitis,pneumonia is
Contact/inoculation(cutaneous anthrax) I:95% M:20%
Hide porters disease
Malignant pustule/blackeschar with necrosis @ center
Ingestion(intestinal anthrax) in I:rare M:95%
Cerebral anthrax: Haemorrhagic CCF
Anthrax bioterrorism category and safety
Type A
BSL 3
Culture bacillus anthrax
PLET
Medusa head
Gelatin stab
Inverted fir tree
Blood agar with penicillin
L forms
Pearl on a string appearance
Nutrient agar
Ground glass appearance
Soil/in Vitro cx : bamboo stick/ box car on gram staining
Investigation
PCR Elisa If Gamma phage typing Multilocus sequence typing Mcfaydean reaction Aescoli’s gel precipitation test
Mcfaydean reaction
Capsule turns blue on methylene blue staining
Aescolis gel precipitation test
Double diffusion single dimension
Virulence factors of anthrax
Oedema factor Lethal factor(cleaves MAPK) Protective antigen factor(Stimulate entry of above two cytolytic toxins)
Historical significance of bacillus anthrax
First bacteria
To be isolated by culture
To be seen under microscope
Used for kochs postulates
To involve a communicable disease through blood
To be found a vaccine
In where precipitation test doneSpores of B.anthrax
Not seen in tissue i.e in Vivo
Seen in soil and culture only
Bacillus cereus
Non sporing
Non capsule
Motile
Gram positive
Toxins of bacillus cereus
Food poisoning(vomitting) Pre formed(<6hrs) Increase in bacteria Increase in cGMP Heat stable
Diarrhoea Not preformed(>12 hrs) Loose stools Decreased number of bacteria Increase in cAMP
Toxins similar to E. coli
Investigation of bacillus cereus
Stool culture MYPA
Diagnostic >10 to power 5 cfu/gm of stool
MYPA
Mannitol
Yolk sac
Phenol red/polymycin
Agar(novo biocin)
PLET Medium
Polymyxin
Lysozyme
EDTA
Thallium acetate
Corynebacterium diphtheria toxins
Toxin A Required from beta phage Tox gene Inhibits EF 2 Inhibits protein synthesis
Toxin B
attachment
Entry of toxin A
Culture media of diphtheria
Loefflers serum slope
Pigment production enhanced
Early detection
Potassium telluride agar
Mitis poached egg
Gravis daisy head
Intermedius frog egg
Bio types of clostridium diphtheriae
Mitis
Endemic
Obstructive
Mild
Intermedius
Epidemic
Hemorrhagic
Moderate
Gravis
Epidemic
Hemorrhagic paralytic
Severe
Belfani
All are nitrate positive except belfani
Other corynebacterium
Immunocompetent Ulcerans (milk) Pseudo tb(zoonosis suppurations lymphadenitis) Arcanobact haemolyticum(beta hemolysis) Minutissimum(erythrasma)
Immunocompromised Jeikium Xerosis Hofmani Equi
C parvum
C urealyticum
Schiks test
Immunogenicity susceptibility testing Intradermal inj of toxin 0.2 ml /1/50 ml Another hand heated inactivated toxin If toxin (+) reaction =susceptible If antitoxin (+)=hypersensitivity
DT toxoid
Formalin treated for 30 days
Dose 25-30 lf units/dose
Older children and adults 1-2 lf units/dose
Lf units
Limes flocculations
Mycobacterium
TB
Lepra
NTB
Mycobacterium tb
Acid fast
Long slender beaded
Bacilli
Aerobic
Culture of tb bacilli
Egg media
LJ medium
Dorset egg media
Liquid BACTEC 460 radiometric method C14 to CO2 BGIT Decreasing O2=increasing fluorescence BACT alert/MBsystem Septi check ESP Culture system 2
Investigation of mycobacterium tb
Gamma interferon assay
Antigen injected
Lymphocyte activated
Gamma interferons
Mantoux(LATENT TB)
Intradermal injection of 0.1ml ppd or 5TU of ppd or 1TU of RT 23 strain
48-72 hrs
10 mm positive exposure in adults or diagnostic in children
5-9 doubtful
<4 negative
IS6110 rflp gene sequencing
M bovis
Spoligotyping(spaced oligonucleotide typing)
Gene expert
CBNAAT
rifampicin resistance
False positive mantoux
Atypical bact kansasi
False negative mantoux
Miliary Tb
Immunocompromised
Measles
Types of tb
Primary/latent
Secondary/active
Primary to
GHONS focus(lower lobe) GHONScomplex LL +enlarged LN Rheinkes complex Calcified enlarged LN
Secondary to
Simons focus
Upper lobe(apex of lung)
Heamatogenous seeding
Ashermans focus
B/L calcified nodules
Infraclavicular
Resistance of tb
Inh Katg Deletion of catalase peroxidase Inh A defect in function of mycolic acid
Rifampicin
RpolB Muatation in rna polymerase beta subunit
Streptomycin
Gamma psl/Rrs
Mutation in ribosomal s12 protein &16srna
Gyr A
Defect in DNA gyrase
Lj medium
Egg solidifying agent
Glycerol dSource of carbon
Malachite green
Time taken in culture and other BACTEC systems
3 to 4 weeks in LJ medium
7 to 14 days in BACTEC
<7 days in NTB IN BACTEC
Preparation of sputum
Petroffs technique
4% NAOH
Disinfectant
For comtaminants
N actylcysteine
Mucolytic agent
Centrifugation
Middle brooks media
7H9
1%proportion technique
Drug sensitivity testing method
Ratio of numbers of colonies in drug containing media to drug free media
> =1 resistance present
acid fast staining concentration
My lepra 5%sulphuric acid My TB 10% Nocardia 1%
Mycobacterium lepra
Acid fast(5%)
Short stout straight bacilli
Foam cells
Cigar bundle appearance in histiocytes/macrophages(>50bacilli)
Clinical features of leprosy
Lionen facies Sagging muscles Nodular lesions Madarosis Claw hand Wrist drop Foot drop
Nerves involved
Ulnar>post auricular nerve
NEVER INVOLVED
MEDIAN POPLITEAL NERVE
Slit skin smear
Buttock Ear lobule Forehead Chin Cheeks Nasal mucosa
4 samples minimum
Bacteriological and morphological index
Bacteriological
No of bacilli
Morphological
No of viable bacilli
=>1 resistance
Types of leprosy
Tuberculoid(CMI) Borderline tuberculoid Borderline Borderline lepromatous Lepromatous (antibody)
Lepra reaction
Three types Type 1 d/t CMI TYPE 4 HS 2 subtypes Reverse and downward Reverse is after drug admin Downward is before drug admin Inflammation in existing lesions Thickening of nerves/neuritis (ulnar nerve M/C) Treatment:glucocorticoid
Type 2 d/t TYPE 3 IC
Erythema nodosum leprosariums
Painful erythematous populist to nodules
Type 3 d/t TYPE 3 IC
Lucio reaction
Diffuse dermal infiltration
Ischemic necrosis of epidermis dermis lower limb mainly
Treatment:glucocorticoid
If not responsive thalidomide ,glucosamine
Culture of lepra
Cannot be cultured
Does not obey Koch postulate
Food pad of mouse(thymectamised to cause lepromatous leprosy)
Footpad of armadillo 9 banded(natural infection with favourable temp for bacilli demonstration in tissue)
Lepromin test
Early Fernandez
Similar to mantoux
48 hrs
Previous exposure present
Late Mitsuda
Due to current injection of Dharmendra antigen
3-4 weeks
Lepromin test vs lepra reaction
Lepromin test
Prognosis of disease
Transition through spectrum
From tuberculoid to lepromatous or vice versa
Intact CMI gives positive results either late or early
Tuberculoid spectrum CMI mediated and hence gives positive results
Lepra reaction
It’s normal in course of disease in relation to treatment
Just a treatment response
But has to be made sure by seeing prognosis of disease by lepromin test
Patient compliance to drug is the cornerstone to cure of disease and so he must be assured of these reactions at the start of treatment
Vaccines for leprosy
ICRC Bacilli
not used
M vaccae immunomodulator function
in Tuberloid to prevent lepromatous
Treatment of leprosy
Paucibacillary
Dapsone daily
Rifampicin monthly
6 months
Multibacillary Dapsone daily Rifampicin monthly Clofazimine monthly 1 year
Single lesion Rifampicin Ofloxacin Minocycline Single dose
Listeria monocytogenes
Only gram positive bacilli to have endotoxins
Tumbling motility @ 25 deg Celsius
Favour growth by cold enrichment (2-8 deg Celsius)
Therefore present in refrigerated foods
Eg cheese
Toxins of listeria
Listeriolysin
Cytotoxin
Both people l/t TH1 response and granuloma
Int A and Int B( e cadtherin)
Actin A ( polymerisation of actin filaments)
Diseases of listeria monocytogenes
Early Granulosus Maternal symptomatic IUtransmission Shortly after birth
Late
Neonatal meningitis
Transmission through health care workers
1 week to 1 month
PALCAM
Stool culture Selective media Polymyxin Acriflavine Lithium chloride Ceftazidime Aesculin Mannitol motility at 25 deg Celsius in palcam Blood/chocolate agar Cold enrichment @ 2 to 8 deg followed by incubation in selective media
Complications of listeria
Septicaemia through maternal IU transmission Chorioamnionitis PROM Preterm birth Abortions
In non pregnant women
Sepsis immunocompromised
Erysipelothrix rhusiopathiae
Swine turkey fish
Erysepeloid(human)
Seal/whale finger Following trauma to hand Reddish blue edematous lesion Alpha haemolytic Hydrogen sulphide
Transmission
Direct inoculation
Animal products
Antons test
Instillation of bacteria in to rabbits eye
Keratoconjuctivitis
