Bacteriology Summary
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Antimicrobial
sensitivity
Biochemical tests
cultureMicroscopic
examination
Laboratory
diagnosis
pathogenicity
Bacteria
penicillin1- Oxidase + Ve2- Utilize : Glucose- maltose
Chocolate blood agar ( transparent or grey colonies incubation in CO2
Gram –Ve dipiococci( intracellular in pus cells )
CSFPyogenic meningitides ( headache- vomiting- stiff neck )
Niesseria meningitidis
Resistant to
penicillin
1- Oxidase + Ve2-
1- Modified New York City
Gram –Ve dipiococci
Urethal & cervical exudates
Gonorrhoeae ( sexual transmitte
Niesseria gonorrhoeae
Utilize : glucose only
( MNYC)2- Thayer martin ( transparent or grey colonies )
( intracellular in pus cells )
- urine – eye swab
d) – acute conjunctivitis in infants of mother with Gonorrhoeae
1- Gram Negative cocci
2- Gram Positive cocciAntimicrobial
sensitivity
Biochemical tests
cultureMicroscopic
examination
Laboratory
diagnosis
pathogenicity
Bacteria
1- All staphylo
1-Blood agar ( yellow to
Gram +Ve in
Pus –skin
Pneumonia –
Staphylococc
cocci are catalase + Ve2- coagulase +Ve3- DNAase +Ve4- liquefy gel5- hemolyse blood
cream colonies some strains beta- haemolytic2- macConkey agar (small deep pink due to lactose fermentation )3- Mannitol salt agar agar ( yellow due to Mannitol fermentation )4- nutrient agar ( golden yellow )
cluster ( grape like cluser )
swab - sputum – CSF – blood – Faeces – vomit in food poisoning
impetigo – wound infection – osteomyelitis – food poisoning due to enterotoxins Normal flora in 40% of health people
us aureus
Penicillin &
Erythromycin
1- sensitive to Bacitracin disk2- anti- streptolysin O ( ASO )
1- Blood agar ( small white beta- haemolytic colonies )2-Crystal violet blood agar ( selective for S. pyoggenes )3- macConkey agar ( no growth )
Gram +Ve in chains,pairs – some strains are capsulated
Throat swab – pus swab - blood
Sore throat ( tonsillitis, pharyngitis ) – scarlet fever – otitis media – impetigo – rhrumatic fever – glomerulonephritis - Normal flora in
Streptococcu
s pyogen
es
( Group A )
upper respiratory tract
Penicillin &
Erythromycin
1- Hippurate hydrolysis +Ve by adding ferric chloride give heavy brown precipitate2- CAMP
1- Blood agar ( grey ,mucoid beta- hemolytic colonies )2- kanamycin blood agar ( selective for S. agalactiae )3- MacConkey agar
Gram +Ve in chains,pairs – some strains are capsulated
CSF – ear swab – vaginal swab - blood
Septic abortion – gynecological sepsis – UTI – neonatal septicemia – meningitis – normal flora in femal genital tract
Strepotococc
us agalac
tiae( Group B )
( extracellular protein produced by S. agalactiae enhance haemolysis with S. aureus beta- lysin
Penicillin ,
Erythro
1- Bile solubility test
1- Blood agar ( mucoid alpha-
Gram +Ve elonga
Sputum – exudate
Lobar pneumonia –
Strepotococc
mycin & co-
trimoxazole
(clear turbidity) 2- sensitive to optochin disk
haemolytic2- chocolate agar with CO2
ted diplococcus – short chains capsulated
s- blood - CSF
bronchitis – meningitis – conjunctivitis – normal flora in upper respiratory tract
uspneumoniae
Gram +Ve in chains
Endocarditis- dental caries – bacteraemiaNormal
StrepotococcusViridia
ns
flora in upper respiratory tract
Sensitive to
Ampicillin &
resistant to
Cephalosporin
1- Aesculin hydrolysis +Ve ( Black- brown color )2- litmust Milk decolorization ( reduce
Grow over wide temperature 10-45 C1- Blood agar 2- macConkey agar ( small pink colonies due to lactose fermentation)3- CLED( small yellow colonies due to lactose fermentation)
Gram +Ve in chains,pairs
Site of infection
UTI – biliary tract – wound- ulcers – endocarditis- meningitis – normal flora in vagina & intestinal tract
Strepotococc
usFecalis( Enterococcus )
( Group D )
litmus milk & give pale yellow color)3- growth in 6.5% NaCl & 40% bile
species Haemolysis Sensitivity to
Bacitracin
CAMP Aesculin Hydrolysis
Streptococcus pyogenesGroup A
Beta sensitive negative negative
Strepotococcus Beta resistant positive negative
agalactiaeGroup B
Strepotococcus Fecalis
Group D
Non haemolytic
resistant negative positive
3- Aerobic and facultative anaerobic Gram negative Bacilli
Biochemical tests
cultureMicroscopic
examination
Laboratory
diagnosis
pathogenicity
Bacteria
1- indole :+ Ve2- motility : +Ve3- MR : +Ve4- nitrare : +Ve
IMVC
1- Blood agar ( some strains are haemolytic2- MacConkey : pink colonies due to lactose fermentation3- CLED : yellow colonies due to lactose fermentation4- XLD : yellow color5- DCA : growth inhibited6- EMB : black colonies
Gram –Ve motile rods
Urine – pus – faeces – CSF - blood
UTI – wound infection – meningitis – bacteraemia in neonates - diarrhea
E. coli
++--with metallic shine6- KIA : yellow butt – yellow slant produce Acid & gas
1- citrate : +Ve2- urease: +Ve3- MR: +Ve/-Ve4- Vp : +Ve/-Ve5- nitrate : +Ve
IMVC--++
1- blood agar : large grey white mucoid colonies2- macConkey : mucoid pink colonies due to lactose fermentation3- CLED : yellow colonies due to lactose fermentation6- KIA : yellow butt – yellow slant produce Acid & gas
Gram –Ve non motile capsulated rods
Urine – pus – sputum
Chest infection (bronchopneumonia – abscesses ) - UTI
Klebsiella
pneumonia
1- urease : +Ve2- PPA: +ve3- motility : +Ve4- Citrate : +Ve
1-bloodagar : fishy odour – swarming2- MacConkey & XLD: swarming inhibited due to bile salts3- CLED : swarming inhibited due electrolyte deficient4- KIA : yellow butt – red slant produce gas & H2S
Gram -Ve pleomorphic rods actively motile
Urinr – pus
UTI ( Alkaline ) – abdominal & wound infection
Proteus
mirabilis
1-KSA :a- Pink ( alkaline ) slope & yellow
1-blood culture ( blood Columbia agar - diphasic medium )2- blood agar ( subculture ):grey-
Gram -Ve rods actively motile – non-
1- for enteric fever ( blood- faeces-
1- Enteric fever ( typhoid & paratyphoid )
salmonella
( acid ) butt indicating fermentation of glucose not lactoseb- produce gas except S. typhic-produce H2S except S. paratyphi
white some strains appear mucoid3- XLD(selective media ):pink color with black center due to H2S4- MacConkey & DCA : pale color with black center
sporing except S. typhi
urine )2- for enterocolitis ( faeces – blood )3- for bacteraemia ( blood )
2- enterocolitis3- Bacteraemia
A2- citrate : +Ve except S. paratyphi A3- MR: +Ve
IMVC-+-+
4- Widal test
( O & H antibodie
s )1-KIA : pink
Selective media1-XLD: red-pink colonies
Gram -Ve1-fresh faecal
Bacillary dysentery
Shigella
(alkaline ) slope & yellow( acid ) butt indicating fermentation of glucose not lactose – no H2S production2- MR: +ve
without black center2-MacConkey & DCA: pale color due to non lactose fermentation –S. sonnei produce pink color on prolonged incubation
specimen2-transport medium for delayed faecal specimen
or shigellosis- transmission by faecal oral route
1-Optimum temp. 27C Small Bubo Plague Yersini
Catalase : +ve2- MR: +ve
( culture should be incubated at room temp.)1-blood agar: small shiny non haemolytic colonies after 24- 48hr.2-macConkey :very small translucent pink after 24-48hr. ( non lactose fermentation but it take up red dye of indicator in the medium )
Gram –Ve coccobacillus – capsulated show bipolar staining with methylene blue, Giemsa
aspirates- sputum- blood
( Bubonic – pneumonic – septicaemic Transimission : 1-infected fleas (Xenopsylla ) from rats or domestic animals ( dogs,cats )2- inhaling
a pestis
organisms in airborn droplets
1- oxidase : +Ve2- Citrate : + Ve3- oxidation- fermentation test :Yellow color ( in oxidative opened
1- blood agar: large flat spreading colonies often are haemolytic2-macConkey : pale color due to NLF3- CLED : geen color due to NLF3- KIA : pink-red slope with metallic appearance – pink-red butt
Gram –Ve motile rod some strains are capsulated- obligatory aerobic Produce pigment
Pus – urine- sputum- effusions - blood
Opportunistic hospital acquired infection1-skin infection ( burn, wound,ulcers )2- UTI ( following catherization )
Pseudomonas aeruginosa
tube )a- blue geenb-yellow green
3- Respiratory tract infection 4- ear infection (otitis externa)5- eye infection
1- oxidase : +Ve2-indole : + Ve
Grow best in alkaline pH1- TCBS ( selective media ):sucrose fermenting yellow colonies 2- KIA: red slope and yellow butt
Gram –Ve curved rods motile ( with
Faecal specimen
rice water stool ( enterotoxin activates adenylate cyclase
Vibrio cholera
3- blood agar : often produce beta haemolytic colonies
single flagellum at one end )
within intestine result in secretion of large fluid & electrolytes transmission by faecal oral routes
1-catalase : +Ve2-oxidase : +Ve3-
B rucella is difficult to isolate & it more isolated from blood in acute brucellosis during time of fever1- tryptone soya (tryptic
Small Gram –Ve coccobacilli or short
1-Blood or bone marrow in acute stage2-
Brucellosis or undulant fever ( zoonotic disease )
Brucella
urease : +Ve
soy )diphasic medium :B. abortus requiring CO2 & keep for weeks with subculture every few days2- serum dextrose agar : smooth,mucoid,rough colony3- B. abortus & B. suis produce H2S
rods serum for serology
1-Oxidase:+Ve 2-Nitrate reduction : +Ve
Grow best moist CO2 & media contain haemin & NAD ( factor X ) or NADP ( factor V )1-chocolate agar2- satellitism test : S.
Small Gram –Ve coccobacillus or short rod
CSF- nasopharyngeal specimens – pus –
1-pyogenic (purulent ) meningitis in young children below 5 years old
Haemophilus influen
zae
aureus in blood agar produce factor V & haemin released by haemolysin enhance growth of H. influenza
blood ( specimens must be cultured as soon as possible & not refrigerated )
2- pneumonia (adult )3- acute epiglottitis ( fatal airway obstruction )4- cellulitis
Oxidase : +Ve
Strict aerobic ( specimens must be cultured as soon as possible )1- Charcoal cephalexin blood agar ( selective &
Small capsulated Gram –Ve cocobacillus
Nasopharyngeal secretion collecte
Whooping cough ( infection of mucosa of upper respiratory
Bordetella
pertussis
enrichment media ) : incubated for 2-6 days in CO2 moist aerobically produce small mercury like mucoid colonies
( singly or in chains )
d by aspiration
tract )
1- oxidase : +Ve2- catalase : +Ve3- Na hippurate hydrolysis : +Ve
Strictly microaerophilic reduired (10% CO2 ) – thermophilic ( 36 – 43 c )1- Blood agar : non haemolytic droplet like colonies2- Butzler virion medium : selective media
Spirally curved motile G-Ve , with faecal smear (1% basic fuchsin)Appear linked to wings of gulls or
Diarrheal feces contain blood ,pus, mucus
Enteritis – watery diarrhea or dysentery ( main source are unpasteurized milk – fecal oral route )
campylobacte
r
"S" or comma shape
1- oxidase : +Ve2- catalase : +Ve3- urease : +Ve
Microaerophilic required CO2 ( grow slowly forming grey translucent colonies within 3-7 days1- blood agar : slightly beta – haemolytic
Small spiral or S shape G-Ve
Gastric biopsy – stool - serum for serology
Chronic gastritis lead to ulceration & may cause gastric carcinoma
Helicobacter pylori
4- Anaerobic Gram Negative Bacteria
1- They ferment wide ranges of carbohydrates ( glucose – maltose – lactose )2- Aesculin hydrolysis : +Ve3- can grow in 20 % Bile tolerant
Strict anaerobic they fastidious they require media containing blood & menadione ( vit. K ) 1- blood agar ; grey , non haemolytic colonies
G-Ve rods pleomorophic
Pus – exudates- infection tissue - blood
Abdominal infection ( particularly following surgery ) – peritonitis – gynaecological infections ( puerperal sepsis )- lung , cerebral abscesses – soft tissue infections
Bacteroides
fragilis
test
5- Anaerobic Gram positive spore forming bacilli Gas
gangrene Clostridium
( myconecrosis ) – food poisoning
perfringens
Tetanus ( lock-jaw ) , fatal disease caused by neurotoxin
Clostridium tetani
Fatal food poisoning cause paralysis ( botulism )
Clostridium
botulinum
Antibiotic Clostri
associated diarrhea ( pseudomembranous colitis )
dium difficile
6-Facultative anaerobic Gram positive spore forming bacilli
Anthrax ( cutaneous – pulmonary – meningoencephalitis ) by herbivore as sheep, cattle, goats
Bacillus
anthracis
Food poisoning from
Bacillus
cereus
infected rice & other cereals
7-Facultative anaerobic Gram positive non spore forming bacilli
Diphtheria ( nasal , nasopharyngeal , tonsillar diphtheria ) in young children – odema of neck – grey
Corynebacteri
um diphtheriae
yellow membrane , it can block the passage of air & cause deathMeningitis & septicemia mainly in ( neonate , pregnant women , elderly persons
Listeria monocytogen
es
8- Spirochetes
Sexual transmitted disease cause 1- sexual acquired Syphilis2-congenital acquired Syphilis
Treponema
pallidium
Leptospirosis ( Flu- like illness ) by
Leptospira
interro
infected animal urine as dogs
gans