I-EMB agar xa ithelekiswa ne-MacConkey agar: ukukhetha nokutolika imidiya

Umfundi uhlwayela isampulu enye yamanzi kwiipleyiti ezimbini. Kwenye kuvela iikholoni ezimnyama ezibengezela ngokwesinyithi okuluhlaza. Kwenye kuvela iikholoni ezipinki eziqaqambileyo ezine-halo emfiliba. Zombini iipleyiti zafakwa isampulu evela kwityhubhu enye, zafukanyelwa ecaleni kwenye, zaza zafundwa ngeyure enye. Umfundi ubuza ukuba yeyiphi ipleyiti echanekileyo.

Zombini iipleyiti zichanekile. Ziphendula imibuzo eyahlukeneyo. Ukudideka kuvela xa ezi media zimbini ziphathwa ngokungathi zizikrini ezitshintshanayo zebhaktiriya zamathumbu. Zinenjongo efanayo, ekukukhetha ii-organism ze-enteric ezi-Gram negative nokwahlula ii-lactose fermenter kwii-nonfermenter, kodwa ziyiphumeza loo njongo ngekhemistri eyahlukileyo nangendlela eyahlukileyo yokubonakala. Wakuba uqonde ezi ngcamango zimbini zisisiseko, ukukhetha ipleyiti nokufunda iikholoni kuba yinto yesiqhelo.

Impendulo emfutshane

I-EMB agar isebenzisa iidayi ezimbini, i-eosin Y ne-methylene blue, ezenza imisebenzi emibini ngaxeshanye: zithintela ukukhula kwee-Gram positive kwaye ziqokelelane zijikeleze abavelisi be-asidi enamandla ukuze zenze iikholoni ezimnyama, ngokwesiqhelo ezibengezela ngokwesinyithi okuluhlaza kwi-Escherichia coli. I-MacConkey agar iyahlula le misebenzi: ii-bile salts kunye ne-crystal violet zithintela ii-Gram positive, i-lactose ixhasa i-fermentation, kwaye i-neutral red ibonisa i-asidi njengeekholoni ezipinki okanye ezibomvu. Ukuba umsebenzi kukubonisa ngokucacileyo nangokuqikelelwayo i-E. coli, i-EMB iluncedo. Ukuba umsebenzi kukwahlula ngokucacileyo ii-lactose fermenter ezipinki kwii-nonfermenter ezingenambala, ngakumbi kwiinkqubo zesitulo okanye zomchamo, i-MacConkey idla ngokuba lula ukuyifunda. Akukho nanye kwezi pleyiti echonga i-organism ngombala kuphela.

EMB: iidayi ezikhethayo nezixela ngaxeshanye

Ingcamango ye-EMB idibanisa ukukhetha nokubonisa kwiimolekyuli ezifanayo. Iprothokholi ye-ASM ye-eosin methylene blue agar ichaza i-EMB njengekhethayo nehlulayo, apho isibini seedayi sithintela ii-organism ezininzi ezi-Gram positive ngelixa i-lactose fermentation ibangela ukufunxwa nokudibana kweedayi. Ifomula eqhelekileyo ka-Levine ine-peptone, lactose, phosphate, eosin Y, methylene blue, kunye ne-agar, njengoko kudwelisiwe kwindlela ye-FDA BAM ye-Levine EMB agar. Qaphela ukuba iiresiphi ezindala ze-EMB ngamanye amaxesha zazifaka i-sucrose kunye ne-lactose, ngelixa i-Levine EMB ine-lactose ngaphandle kwe-sucrose, ngoko bhala ukuba yeyiphi ifomula egcinwa yilabhoratri yakho.

Ukufunda i-EMB kuthetha ukufunda indlela iidayi eziziphatha ngayo. I-lactose fermentation enamandla ivelisa i-asidi eyaneleyo ukuba ibangele ukudibana okukhulu kweedayi, nto leyo enika i-E. coli amaziko ayo amnyama aluhlaza ukuya kumnyama kwaye, kwimeko eqhelekileyo, ukubengezela ngokwesinyithi okuluhlaza ekukhanyeni okubuyisiweyo. Ii-fermenter ezibuthathaka ezifana ne-Enterobacter ne-Klebsiella zidla ngokukhula njengeekholoni ezipinki ukuya kwezimfusa, ezine-mucoid texture, ngaphandle kokubengezela. Ii-nonfermenter ezifana ne-Salmonella, Shigella, ne-Proteus ngokubanzi zikhula njengeekholoni ezingenambala okanye ezikhanyayo kuba azivelisi ukuqhuma kwe-asidi okubangela ukudibana kweedayi. Ii-Gram positive zidla ngokuthintelwa, nangona umlinganiselo wolo thintelo uhluka ngokohlobo lwe-strain nemveliso. Ikhemistri epheleleyo yokulungiswa kweedayi, kuquka ukuba kutheni i-methylene blue iziphatha njenge-cationic stain kwasekuqaleni, yeyengxoxo eyahlukileyo ngeefomula zeedayi, kwaye umxholo obanzi we-microscopy uku-atlasi yeendlela zokusteyina. Eli nqaku ligxile ekukhetheni nasekufundeni iipleyiti.

Umfanekiso ongentla ngowokucacisa. Ubonisa indlela yokubonakala omele uyilindele: iikholoni ezimnyama ezibengezelayo, iintlobo ezipinki ezine-mucoid texture, kunye neentlobo eziphaphathekileyo kwi-EMB, xa kuthelekiswa neentlobo ezipinki neziphaphathekileyo kwi-MacConkey. Wusebenzise ukufunda ipateni, emva koko uqinisekise isigqibo ngasinye usebenzisa ii-control ezifotiweyo kunye nephepha lemveliso le-medium kanye oyisebenzisayo ebhentshini yakho.

MacConkey: imisebenzi eyahluliweyo, umthetho wokubonakala olula

Ingcamango ye-MacConkey yabela umsebenzi ngamnye kwisithako esahlukileyo. Iprothokholi ye-ASM ye-MacConkey agar ibonisa indlela efanayo yokukhetha nokwahlula, kwaye indlela ye-FDA BAM ye-MacConkey agar idwelisa amacandelo asebenzayo: ii-peptone, lactose, bile salts, salt, neutral red, crystal violet, kunye ne-agar. Ii-bile salts kunye ne-crystal violet zikhetha ngokuchasene nee-Gram positive. I-lactose ibonelela nge-substrate ye-fermentation. I-neutral red isebenza njengesalathisi se-pH, ijike ibe pinki ukuya kubomvu apho kwakheka khona i-asidi, ngamanye amaxesha kunye ne-bile edibeneyo ejikeleze ii-fermenter ezinamandla.

Umthetho wokufunda wenziwe walula ngabom: ipinki ithetha i-lactose fermenter, kwaye ukungabi nambala okanye ukuphaphatheka kuthetha i-nonfermenter. I-E. coli ibonakala ipinki ukuya kubomvu, rhoqo ine-halo ye-bile precipitate. I-Klebsiella ne-Enterobacter zibonakala zipinki kwaye rhoqo zine-mucoid texture ngenxa yee-capsule zazo. I-Salmonella, Shigella, Proteus, kunye nezinye ii-rod ezininzi ezi-Gram negative zibonakala zingenambala. Kukho nenye inzuzo ebalulekileyo kwiilabhoratri zokufundisa: ii-bile salts ngokubanzi zinciphisa ukusasazeka kwe-Proteus, ngoko kulula ukufumana iikholoni ezahluliweyo kwi-MacConkey kunakwimidiya engakhethiyo, nangona olo thintelo lungagqibelelanga kwaye kukho ezinye iindlela ezingenayo i-salt apho ukulawula ukusasazeka kuyeyona nto iphambili.

Isizathu semolekyuli sokuba iidayi ziziphathe ngale ndlela sibuyela kwi-charge nakwisakhiwo. I-Methylene blue yi-cationic phenothiazine dye apho isakhiwo neempawu zayo zichaza ukuthanda kwayo imiphezulu yebhaktiriya ene-asidi, nto leyo ikwangulo mtsalane usebenzayo xa idibana kwiindawo ezine-asidi kwi-EMB.

Uthelekiso ngokukhawuleza

Funda itheyibhile njengendlela yokwenza isigqibo. Xa umsebenzi ufuna abafundi babone uluhlu lwamandla e-fermentation olunencopho enye ebonakala kakhulu, i-EMB iyakubonisa oko. Xa umsebenzi ufuna ulwahlulo olukhawulezayo lweendidi ezimbini ngaphambi kokuqinisekiswa nge-biochemical testing, i-MacConkey iyakubonisa oko.

Yeyiphi i-medium yesampulu nganye

Kwimisebenzi yamanzi ejolise ekuqapheleni ngokwethutyana i-fecal coliform okanye i-E. coli, i-EMB inomtsalane kuba ukubengezela kwayo kulula ukukwahlula. I-MacConkey nayo iyakwazi ukuphatha ii-enteric Gram negatives kwaye inembali yokusetyenziswa emanzini, kodwa akukho nanye kwezi pleyiti ethatha indawo yendlela esemthethweni yokuvavanya amanzi, enokuchaza imidiya efana ne-modified mTEC okanye MI ngokuxhomekeke kuvavanyo. Jonga indlela ekufuneka ilabhoratri yakho iyilandele.

Kwiintlobo zokwahlula zesampulu yesitulo phakathi kwee-fermenter nee-nonfermenter, i-MacConkey ngokubanzi iluncedo ngakumbi kwezi zimbini. Umsebenzi oqhelekileyo wesitulo wokukhangela i-Salmonella okanye i-Shigella udla ngokongeza imidiya ye-enteric ekhetha ngakumbi efana ne-XLD okanye i-Hektoen enteric endaweni yokuxhomekeka kwi-MacConkey kuphela.

Kwimisebenzi yokufundisa ngesampulu yomchamo elinganisa inkqubo yeklinikhi, dibanisa i-MacConkey ne-blood agar. I-MacConkey inika ulwahlulo lokuqala lwee-Gram negative ngelixa i-blood agar ibuyisa ii-organism ezithintelwa yi-MacConkey. Olu dibaniso luqhelekile kwiinkcazelo zeklinikhi zokulungiselela i-urine culture.

Ukufundisa ingcamango ngokwayo, sebenzisa zombini. I-EMB ifundisa ukuba amandla e-fermentation abalulekile kwaye imolekyuli enye inokwenza imisebenzi emibini. I-MacConkey ifundisa uyilo lweemodyuli: umkhethi, i-substrate, kunye nomxeli zigcinwa zahlukene. Abafundi abahlwayela i-E. coli eyaziwayo, i-Klebsiella aerogenes eyaziwayo, kunye ne-Salmonella eyaziwayo ecaleni kwenye kwimidiya yomibini kunqabile ukuba baphinde badideke kwezi ndlela zimbini.

Imigibe yokufunda ephindaphindeka rhoqo kwikota nganye

Eyona mpazamo ixhaphakileyo kukuchonga nge-color kuphela. Ipinki kwi-MacConkey ingaba yi-E. coli, Klebsiella, Enterobacter, okanye enye i-fermenter. Ukungabi nambala kungaba yi-Salmonella, Shigella, Proteus, Pseudomonas, okanye enye i-nonfermenter. Umbala yi-screening phenotype ekhokelela kumsebenzi wokuqinisekisa ofana ne-Gram stain, oxidase, biochemical panels, okanye ukuchongwa ngesixhobo, hayi igama le-species.

Impazamo yesibini kukunika intsingiselo enkulu kakhulu xa kungekho kubengezela. Ezinye iikholoni zokwenene ze-E. coli, ngakumbi ezahlulwe kakuhle, zivelisa ukubengezela kwesinyithi okuncinane okanye akukho kwaphela kwi-EMB. Ukungabikho kokubengezela akuyikhuphi i-E. coli, kwaye ukubakho kwako akuyiqinisekisi. Phatha ukubengezela njengophawu lokuqikelela kuphela.

Impazamo yesithathu kukuthelekisa iipleyiti ezineminyaka eyahlukileyo. Ii-lactose fermenter ezilibazisekileyo zinokujika zibe pinki kwi-MacConkey emva kokufukanyelwa ixesha elide, nto leyo eyenza ulwahlulo olucacileyo phakathi kwe-fermenter ne-nonfermenter lungabi luhle. Funda ngeyure echazwe yilabhoratri kwaye ubhale ixesha lokufukanyelwa kunye nesiphumo.

Impazamo yesine kukufunda ukukhula okuxubeneyo njenge-organism enye. Ikholoni epinki ecaleni kwekholoni engenambala ibonisa ii-phenotype ezimbini, hayi imeko ephakathi. Khetha iikholoni ezahlulwe kakuhle kwaye usebenze nge-morphotype nganye ngokwahlukeneyo. I-mucoid texture nayo inomgibe ofanayo: zombini i-Klebsiella ne-Enterobacter zinokubonakala zine-mucoid texture, ngoko i-capsule yodwa ayisoze igqibe igama. I-organism eyayifundiswa njenge-Enterobacter aerogenes ngoku ihlelwa njenge-Klebsiella aerogenes, nto leyo ecacisa ukuba kutheni iitshathi ezindala kunye neelebhile ezintsha zibonakala zingavumelani.

Ii-control kunye nomthetho wokuvala

Sebenzisa ii-control ezifotiweyo okanye ezintsha kwiseshoni nganye: i-E. coli yokubonisa impendulo ye-fermenter enamandla, i-Klebsiella aerogenes yokubonisa i-mucoid fermentation ngaphandle kokubengezela okuqhelekileyo, i-strain ye-Salmonella yokubonisa impendulo ye-nonfermenter engenambala, kunye ne-Staphylococcus aureus ukuqinisekisa ukuthintelwa kwe-Gram positive kwimveliso kanye oyisebenzisayo. Tshatisa iinombolo ze-strain kunye nemigaqo yokwamkelwa nephepha lomenzi, kuba ukukhetha kuyatshintsha ngokuxhomekeke kumxholo we-bile, crystal violet, kunye nedayi.

Khumbula isivakalisi esinye ebhentshini. I-EMB isebenzisa iidayi ezikhethayo nezithethayo ngaxeshanye, nto leyo enika uphawu olucacileyo lwe-E. coli kodwa ifune ukufundwa okuneenkcukacha ngakumbi. I-MacConkey yahlula ukukhetha ekuxeleni, nto leyo enika ulwahlulo olulula phakathi kwepinki nephaphathekileyo kodwa inike iinkcukacha ezimbalwa ze-fermentation. Khetha i-medium enengcamango ehambelana nombuzo, qinisekisa umbala ngovavanyo olufanelekileyo, kwaye ezi pleyiti zimbini ziyeke ukukhuphisana ziqalise ukusebenzisana.