kuliah 4 flora normal gi tract
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Flora Normal GI TractTRANSCRIPT
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Normal flora of human intestinal tractDini AgustinaMikrobiologi FKUJ5/19/[email protected]
Ingat Kembali.....5/19/[email protected]
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Oral CavityThe foetus in the womb is normally sterile. Depends on the successive transmission of microorganisms to the site of potential colonization. By passive transfer from theMother, lactobacilli and Candida from the birth canalOrganisms present in milk, water (and eventually food), and The general environment, although saliva is probably the main vehicle for transmission5/19/[email protected] first microorganisms to colonize are termed pioneer species the pioneer microbial community : streptococci and in particular, S. salivarius, S. mitis and S. oralisFirst year of life, members of the genera Neisseria, Veillonella, Actinomyces, Lactobacillus, and Rothia are commonly isolated, particularly after tooth eruptionMean age of 3 months (range: 17 months), Prevotella melaninogenica, Fusobacterium nucleatum, Veillonella spp., and non-pigmented Prevotella spp5/19/[email protected] OF THE RESIDENT ORAL MICROFLORA IN HEALTHReduce or prevent colonisation pathogen by Bacteriocin productionex: S. salivarius strains produce a bacteriocin (termed enocin or salivaricin) with activity against Lancefield Group A streptococci Change local environmental conditions (e.g pH or redox potential)Produce other inhibitors such as volatile fatty acids or hydrogen peroxide
which may exclude exogenous species and suppress opportunistic pathogens.
ex: the production of hydrogen peroxide by members of the S. mitis-group can suppress the growth in plaque of potential periodontal pathogens, such as A.actinomycetemcomitans.Upper GIStomach, duodenum, jejenum, upper ileumSparse microflora: < 104 org/ml intestinal secretion Derived from: oropharing, gut (each meal)Colonisasi coliform abnormal V.cholera dan ETEC
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Stomach 5/19/[email protected] kind of organism would live in a highly acidic (pH 1-2) environment like the stomach?
http://www.colorado.edu/outreach/BSI/k12activities/interactive/actidhpnf.html5/19/[email protected]
5/19/[email protected] into the stomachs mucosal lining to a depth where the pH is essentially neutral.
Produce an enzyme called urease to convert urea produced by the stomach into ammonia and carbon dioxide.Creates a less acidic microenvironment. 5/19/[email protected]://www.medscape.org/viewarticle/457393_5
The History and Future of H. pylori Barry J. Marshall5/19/[email protected]
able to sense the pH gradient in the mucus and move towards the less acidic region (chemotaxis)5/19/[email protected]
http://en.wikipedia.org/wiki/Helicobacter_pylori5/19/[email protected]
A relatively hospitable environment then stomachDifficult for bacteria to colonize they get washed out very quickly (3-5 hours for food to move through the small intestine)Human enzymes carry out most of the digestion processes5/19/[email protected] IntestineConcentration of bacteria in the small intestine remains relatively low (106 bacteria/ml) andLuxuriant microflora: 1011 bacteria/g of stool24-48 hours for food to travel through the colon (slower flow rate) gives bacteria to reproduce reach very high concentrationsBacteri anaerob: bacteriodes, streptococci, clostridia5/19/[email protected] Intestine5/19/[email protected]
EnterobacteriaceaePendahuluan Sebagai flora normal menghambat pertumbuhan kuman patogendigunakan sebagai indikator pencemaran air oleh tinja.Sering menyebabkan infeksi nosokomial.Apabila keluar dari habitatnya akan menyebabkan infeksi
5/19/[email protected] Enterobacteriaceae often referred to as entericsFour major features:All ferment glucose (dextrose)All reduce nitrates to nitritesAll are oxidase negativeAll except Klebsiella, Shigella and Yersinia are motile
5/19/[email protected] and Colony MorphologyGram negative bacilli or coccobacilliNon-spore formingColony morphology on BAP or CA of little value, as they look the same, except for KlebsiellaSelective and differential media are used for initial colony evaluation (ex. MacConkey, HE, XLD agars)
5/19/[email protected] BASED ON LACTOSE FERMENTATION
Lactose fermenters Escherichia coli Klebsiella sp. Late lactose fermenters Shigella sonnei Para colons etc No lactose fermenters Salmonella Shigella etc.5/19/[email protected]
5/19/[email protected] of Enterics
5/19/[email protected] and Antigenic Factors of EntericsAbility to colonize, adhere, produce various toxins and invade tissuesSome possess plasmids that may mediate resistance to antibioticsMany enterics possess antigens that can be used to identify groupsO antigen somatic, heat-stable antigen located in the cell wallH antigen flagellar, heat labile antigenK antigen capsular, heat-labile antigen 5/19/[email protected]
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Dry, pink (lactose positive) colony with surrounding pink area on MacConkeyInfectionsWide range including meningitis, gastrointestinal, urinary tract, wound, and bacteremia5/19/[email protected]
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5/19/[email protected] found in GI tractFour major speciesK. pneumoniae is mostly commonly isolated speciesPossesses a polysaccharide capsule, which protects against phagocytosis and antibiotics AND makes the colonies moist and mucoidHas a distinctive yeasty odorFrequent cause of nosocomial pneumoniaKlebsiella species 5/19/[email protected]
Mocoid, pink (lactose positive) colony with surrounding pink area on MacConkey5/19/[email protected] of 12 species; E. cloacae and E. aerogenes are most commonIsolated from wounds, urine, blood and CSFMajor characteristicsColonies resemble KlebsiellaMotileMR negative; VP positive
Enterobacter species5/19/[email protected]
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5/19/[email protected] speciesSeven species, but S. marcescens is the only one clinically importantFrequently found in nosocomial infections of urinary or respiratory tractsImplicated in bacteremic outbreaks in nurseries, cardiac surgery, and burn unitsFairly resistant to antibiotics5/19/[email protected] species (contd)Major characteristicsFerments lactose slowlyProduce characteristic pink pigment, especially when cultures are left at room temperature
S. marscens on nutrient agar
5/19/[email protected], Morganella & Providencia speciesAll are normal intestinal floraOpportunistic pathogensDeaminate phenylalanineAll are lactose negative5/19/[email protected] speciesP. mirabilis and P. vulgaris are widely recognized human pathogensIsolated from urine, wounds, and ear and bacteremic infectionsBoth produce swarming colonies on non-selective media and have a distinctive burned chocolate odorBoth are strongly urease positiveBoth are phenylalanine deaminase positive
5/19/[email protected] species (contd)A exhibits characteristic swarmingB shows urease positive on right
5/19/[email protected] Salmonella on MacConkey
5/19/[email protected] (contd)Lactose negativeNegative for indole, VP, phenylalanine deaminase, and ureaseMost produce H2SDo not grow in potassium cyanideLarge and complex group of organisms; grouped by O, H, and Vi (for virulence) antigens5/19/[email protected]
5/19/[email protected] speciesClosely related to the EscherichiaAll species cause bacillary dysenteryS. dysenteriae (Group A)S. flexneri (Group B)S. boydii (Group C)S. sonnei (Group D)
5/19/[email protected] (contd)CharacteristicsNon-motileDo not produce gas from glucoseDo not hydrolyze ureaDo not produce H2S on TSILysine decarboxylase negativedelayed lactose Fragile organisms Possess O and some have K antigens5/19/[email protected]
5/19/[email protected] speciesConsists of 11 named speciesYersinia pestisCauses plague, which is a disease primarily of rodents; transmitted by fleasTwo forms of plague, bubonic and pneumonicGram-negative, short, plump bacillus, exhibiting safety-pin or bipolar staining5/19/[email protected]
5/19/[email protected]/19/[email protected]://microbewiki.kenyon.edu/index.php/Intestinal_Microflora_and_Antibiotic_ResistanceB a t a b y a l e t a l . , 2012. Role of the oral micro flora in human population: A brie f re view. Int. J. of Pharm. & Life Sci. (IJPLS). 3(12)A.M. OHara & F. Shanahan. 2006. The gut flora as forgotten organ. EMBO reports. VOL 7 | NO 7 Microbiology of GI Track. www.ncbi.nlm.gov/books/NBK7670
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