Into Ebangela Ezi Ntsholongwane Ziphinde Zivuke

KUCACILE ukuba iintlobo ngeentlobo zeentsholongwane zabakho ekuqaleni kokubakho kwezidalwa eziphilayo emhlabeni. Ezi ntsholongwane zincinane kakhulu ziye zakwazi ukuphila phantsi kweemeko ezimaxongo apho ezinye izidalwa zingenakukwazi ukuphila khona. Zifumaneka kwiintunja ezimpompoza amanzi atshisayo kumazantsi olwandle nakumanzi abanda nkca akwi-Arctic. Ngoku ezi ntsholongwane azifi naxa kusetyenziswa awona mayeza anamandla enzelwe ukubulala iintsholongwane.

Kwiminyaka elikhulu eyadlulayo, yayisaziwa into yokuba ezinye iintsholongwane zibangela izifo, kodwa ngelo xesha kwakungekho mntu uwaziyo amayeza okubulala iintsholongwane. Ngoko xa umntu ehlaselwa sisifo esasulelayo, oogqirha abaninzi babengenanto ingako banokuyenza ngaphandle kokuthuthuzela lowo ugulayo. Kwakufuneka ukuba inkqubo yomntu yokuzikhusela komzimba ilwe neso sifo. Xa inkqubo yokuzikhusela komzimba ingenamandla okulwa neso sifo, imiphumo yayidla ngokuba lusizi. Nokuba umntu unomkrwelwana nje ongephi, wayedla ngokufa xa loo mkrwelwana ungenwe ziintsholongwane.

Ngaloo ndlela, kwafunyanwa iyeza lokuqala lokubulala iintsholongwane. Emva kokuba kuqaliswe ukusetyenziswa kwee-sulfa drugs ngeminyaka yee-1930 namayeza afana ne-penicillin ne-streptomycin ngeminyaka yee-1940 kwafunyanwa namanye amayeza amaninzi kumashumi eminyaka elandelayo. Ngeminyaka yee-1990, amayeza okubulala iintsholongwane ayequka imixube eli-150 yamayeza aziintlobo ezili-15 ezahlukahlukeneyo.

Ukuthi Shwaka Kwamathemba Okoyisa Le Ngxaki

Ngeminyaka yee-1950 neyee-1960 abanye abantu babevuya becinga ukuba ingxaki yezifo ezasulelayo yoyisiwe. Kwanabo banolwazi ngeentsholongwane babecinga ukuba ezi zifo ziya kuba yinto yezolo. Ngowe-1969 ingcali yamayeza yaseUnited States yanikela ubungqina phambi kweBhunga Lowiso-mthetho bokuba kungekudala abantu “baza kuyeka ukuxhalaba ngenxa yezifo ezasulelayo.” Ngowe-1972, uMacfarlane Burnet owathweswa imbasa kaNobel noDavid White babhala: “Kubonakala ngathi kwixa elizayo akuyi kubakho sizathu sakuxhalaba ngenxa yezifo ezasulelayo.” Eneneni, abanye babevakalelwa kukuba izifo ezinjalo ziya kupheliswa kuthi tu.

Inkolelo yokuba izifo ezasulelayo zinokunyangeka yabangela ukuba kubekho ukuzithemba ngokugqithiseleyo. Omnye umongikazi owayeyazi kakuhle ingozi eyayibangelwa ziintsholongwane ngaphambi kokuba kubekho amayeza okubulala iintsholongwane, waphawula ukuba abanye abongikazi abaselula babengenankathalo kangako ngococeko. Xa ebakhumbuza ukuba bahlambe izandla babedla ngokuphendula bathi: “Ungakhathazeki, ngoku sinamayeza okubulala iintsholongwane.”

Ukanti, ukuthembela kumayeza okubulala iintsholongwane nokusetyenziswa kwawo ngomlinganiselo ongaphaya kwengqondo kwaba nemiphumo eyingozi gqitha. Izifo ezasulelayo ziye zaqhubeka zikho. Ngapha koko, ziye zaba ngoyena nobangela uphambili wokufa kwabantu ehlabathini! Abanye oothunywashe abaye baba negalelo ekusasazekeni kwezifo ezasulelayo ziziphithiphithi ezibangelwa yimfazwe, ukuxhaphaka kokungondleki kumazwe asakhasayo, ukungabikho kwamanzi acocekileyo, inkqubo yogutyulo engekho mgangathweni, ukukwazi ukundwendwela kwamanye amazwe ngokukhawuleza notshintsho kwimozulu emhlabeni wonke.

Iintsholongwane Ezingeva Yeza

Ukungeva yeza kweentsholongwane eziqhelekileyo kuye kwangqineka kuyingxaki enkulu, ngxaki leyo ingaqondakaliyo kuluntu ngokubanzi. Ukanti, xa siqwalasela bonke oothunywashe, ingxaki yeentsholongwane ezingeva yeza yayifanele ukuba iye yabonwa kusengaphambili. Ngoba? Ngokomzekelo, cinga ngento eyenzekayo ukuqalisa kokusetyenziswa kwe-DDT phakathi kwiminyaka yee-1940.a Ngelo xesha, abasebenzi basederi bavuya kuba iimpukane zanyamalala emva kokuba befake isipreyi se-DDT. Kodwa kukho ezimbalwa ezingazange zife, yaye inzala yazo yakwazi ukumelana ne-DDT. Kungekudala ezi mpukane zingafiyo yi-DDT, zanda.

Kwanangaphambi kokuba kusetyenziswe i-DDT, nangaphambi kokuba kusetyenziswe i-penicillin ngowe-1944, iintsholongwane eziyingozi zabonakala ukuba zinamandla okumelana namayeza. UGqr. Alexander Fleming, owenza i-penicillin wakuqonda oku. Kwilebhu yakhe, wabukela izizukulwana ngezizukulwana ze-Staphylococcus aureus (i-hospital staph) zisiba neeseli eziluqilima ezazibangela ukuba ezi ntsholongwane zibe namandla okumelana naloo penicillin.

Ngenxa yoku, malunga neminyaka engama-60 eyadlulayo uGqr. Fleming walumkisa ngelithi iintsholongwane eziyingozi ezisemntwini zisenokugqibela ngokungayiva i-penicillin. Ngoko, ukuba i-penicillin ayikwazanga ukubulala zonke iintsholongwane eziyingozi, inzala yezo zingakhange zife iyanda. Ngenxa yoko, eso sifo singakhange sinyangeke nge-penicillin siphinda siqale phantsi.

Incwadi ethi The Antibiotic Paradox ithi: “Into eyathethwa ngulo kaFleming yaba nemiphumo ebuhlungu nangaphezu kokuba yena wayecinga.” Njani? Kaloku, kwafunyaniswa ukuba kwezinye iintsholongwane, kukho imizila yemfuza ekwi-DNA ekhupha imichiza ethile ebangela ukuba i-penicillin ingasebenzi. Ngenxa yoko, enoba umntu angasebenzisa i-penicillin ixesha elide kangakanani idla ngokungamncedi. Ezinjani zona ukothusa iindaba!

Ngelizama ukoyisa izifo ezasulelayo, kwakusoloko kuveliswa amayeza amatsha okubulala iintsholongwane ukususela ngeminyaka yee-1940 ukusa kweyee-1970 yaye kwenziwa nenye imbinana yala mayeza ngeminyaka yee-1980 neyee-1990. La mayeza matsha akwazi ukubulala iintsholongwane ezazifudula zingafi ngamayeza angaphambili. Kodwa kwiminyaka nje embalwa, ezi ntsholongwane zawoyisa nala amatsha amayeza.

Abantu baye bafumanisa ukuba iintsholongwane zisebenzisa ubuchule obumangalisayo xa zizikhusela ekubulaweni ngamayeza okubulala iintsholongwane. Iintsholongwane ziyakwazi ukutshintsha iseli yazo engaphandle ukuze zithintele iyeza lingangeni emizimbeni yazo okanye zikhuphe imichiza ethile ukuze zingabulawa lelo yeza. Kwelinye icala, iintsholongwane zisenokulikhupha ngoko nangoko iyeza xa ligqiba kungena okanye zisenokulenza lingasebenzi ngokulahlukanisa.

Njengoko ukusetyenziswa kwamayeza okubulala iintsholongwane kuyinto exhaphakileyo, iintsholongwane ezikwaziyo ukumelana nala mayeza ziya zisanda. Ngaba oku kuthetha ukuba la mayeza akasebenzi kwaphela? Akunjalo, kwiimeko ezininzi ayasebenza. Ukuba elinye iyeza lokubulala iintsholongwane alisebenzi ukunyanga isifo esithile, elinye lidla ngokusebenza. Iintsholongwane ezingeva yeza bezisoloko ziyingxaki kodwa mvanje le ngxaki iye yalawuleka.

Ukumelana Nezibulali-zintsholongwane Ezininzi

Izazinzulu zezonyango zothuka kakhulu zakufumanisa ukuba iintsholongwane ziyakwazi ukudlulisela imizila yemfuza kwezinye iintsholongwane. Ekuqaleni kwakucingwa ukuba ziintsholongwane zohlobo olufanayo ezikwaziyo ukudlulisela imizila yemfuza kwezinye iintsholongwane. Kodwa kamva, le mizila ibangela ukuba iintsholongwane zikwazi ukumelana namayeza yafunyanwa kwiintlobo ngeentlobo zeentsholongwane. Ngenxa yoku, iintlobo ngeentlobo zeentsholongwane ziye zakwazi ukumelana namayeza amaninzi adla ngokusetyenziswa.

Into eyaba buhlungu nangakumbi kukuba uphando olwenziwa ngeminyaka yee-1990 lwabonisa ukuba ezinye iintsholongwane ziyakwazi ukumelana namayeza zingakhange zifumane imizila yemfuza yolunye uhlobo lwentsholongwane. Enoba kusetyenziswe uhlobo olunye lweyeza lokubulala iintsholongwane, ezinye iintsholongwane ziyakwazi ukumelana neentlobo ezininzi zala mayeza, enoba enziwe ngezinto zemvelo okanye ngemixube yemichiza.

Ikamva Elimfiliba

Nangona amayeza amaninzi okubulala iintsholongwane esebenza kuninzi lwabantu namhlanje, aya kuba eluncedo kangakanani kwixa elizayo? Incwadi ethi The Antibiotic Paradox ithi: “Asinakulindela ukuba nasiphi na isifo sinokunyangeka ngesibulali-zintsholongwane esiye sasetyenziswa kuqala.” Le ncwadi yongezelela ithi: “Kwezinye iindawo ehlabathini, ngenxa yokuba embalwa amayeza okubulala iintsholongwane kuye kungafumaneki yeza lokunyanga isifo esithile. . . . Izifo ekwakuthiwe ziya kunyangwa ziphele nya kwiminyaka engama-50 eyadlulayo, zizo ezibulala abantu.”

Iintsholongwane ezibizwa ngokuba zii-bacteria akuphela kweentsholongwane ezingeva yeza. Nezinye iintsholongwane ezibizwa ngokuba zii-virus nee-fungi nezinye izinambuzane ezincinane ziye zakwazi ukumelana namayeza, ngaloo ndlela zibangela ingxaki ehlabathini lonke, zitshitshisa yonke imizamo yokufumana amayeza amatsha okulwisana nazo.

Yintoni ke ngoko enokwenziwa? Ngaba le ngxaki inokupheliswa okanye incitshiswe? Yintoni enokwenziwa ukuze amayeza okubulala iintsholongwane aqhubeke eluncedo kweli hlabathi linezifo ezininzi ezasulelayo?

[Umbhalo osemazantsi]

[Ibhokisi/Umfanekiso okwiphepha 16]

Yintoni Amayeza Okubulala Iintsholongwane?

Isibulali-zintsholongwane osinikwa ngugqirha siphantsi kohlobo oluthile lwamayeza. Ngokuqhelekileyo la mayeza aphantsi kwe-“chemotherapy,” yaye eli gama libhekisela ekunyangeni isifo ngemichiza. Ngoxa igama elithi “chemotherapy” lidla ngokusetyenziswa xa kubhekiselwa kunyango lomhlaza, ngaphambili lalibhekisela—ukanti nangoku lisabhekisela—kunyango lwezifo ezasulelayo. Xa kunjalo, olu hlobo lonyango kudla ngokuthiwa yi-antimicrobial chemotherapy.

Iintsholongwane zincinane kakhulu kangangokuba zinokubonwa ngemikroskopu kuphela. Amayeza okubulala iintsholongwane yimichiza yokubulala iintsholongwane ezibangela izifo. Ngelishwa, la mayeza okubulala ezi ntsholongwane ayingozi nakwiintsholongwane eziluncedo emzimbeni.

Ngowe-1941, uSelman Waksman, ongomnye wabo benza i-streptomycin, wasebenzisa igama elithi “antibiotic” xa ethetha ngamayeza okubulala iintsholongwane. Amayeza okubulala iintsholongwane aluncedo ngenxa yokuba axutywe netyhefu ethile. Oku kuthetha ukuba anokubulala iintsholongwane kodwa angakwenzakalisi.

Noko ke, onke amayeza okubulala iintsholongwane ngandlel’ ithile ayityhefu nakuthi. Umlinganiselo weyeza onokubulala iintsholongwane nalowo unokuba yingozi kuthi ubizwa ngokuba yi-therapeutic index. Xa le index iphakamile akuyongozi ukusebenzisa elo yeza; ukanti xa iphantsi kuyingozi ukulisebenzisa. Eneneni, kukho amawaka emichiza eye yafunyanwa, kodwa ayiloncedo ngenxa yokuba iyingozi ebantwini okanye kwizilwanyana.

Isibulali-zintsholongwane sokuqala esasinokuselwa yi-penicillin, eyenziwe nge-Penicillium notatum. I-penicillin yaqala ukutofelwa emithanjeni ngowe-1941. Kungekudala emva koko, ngowe-1943, kwenziwa i-streptomycin nge-Streptomyces griseus, intsholongwane efumaneka emhlabeni. Ekuhambeni kwexesha, kwenziwa amayeza amaninzi okubulala iintsholongwane, athatyathwe kwizinto eziphilayo nalawo enziwe ngemichiza. Ukanti, iintsholongwane ziye zakwazi ukumelana noninzi lwala mayeza, nto leyo eye yabangela ingxaki ehlabathini jikelele.

[Umfanekiso]

Isicuku se-penicillin osibona ezantsi kulo mfanekiso sithintela intsholongwane ukuba ingakhuli

[Inkcazelo]

Christine L. Case/Skyline College

[Ibhokisi/Imifanekiso ekwiphepha 17]

Iintlobo Ngeentlobo Zeentsholongwane

Ii-Virus zezona ntsholongwane zincinane. Zizo ezibangela izigulo eziqhelekileyo njengomkhuhlane, ifiva nomqala. Ii-virus zikwabangela nezifo eziyingozi njengepoliyo, i-Ebola noGawulayo.

Ii-Bacteria zineseli enye kuphela, azina-nucleus yaye zine-chromosome enye kuphela. Emizimbeni yethu kukho amawaka ezigidi zee-bacteria, inkoliso yazo ifumaneka kumetyiso. Ziyasinceda ukuba setyise ukutya yaye zingowona mthombo kufumaneka kuwo uvithamini K, oluncedo ekunqumiseni igazi.

Kwiintlobo ngeentlobo ezingama-4 600 zee-bacteria zezimalunga nama-300 kuphela ezigqalwa njengee-pathogens (ezibangela izifo). Sekunjalo, ezi ntsholongwane zibangela izifo ezininzi kwizityalo, kwizilwanyana nasebantwini. Ezi zifo ziquka isifo sephepha, ikholera, umqala omhlophe, i-anthrax, ukubola kwamazinyo, iintlobo ezithile zenyumoniya nezifo eziliqela ezidluliselwa ngesini.

Ii-Protozoans, ngokufanayo nee-bacteria, zineseli enye kodwa zona zisenokungabi ne-nucleus enye. Ezinye zazo yi-amoeba, ii-trypanosomes kunye nesifunxi-gazi esibangela imalariya. Malunga nesinye kwisithathu seentsholongwane eziphilayo zizifunxi-gazi—kukho malunga neentlobo ngeentlobo zazo ezimalunga ne-10 000—nangona zimbalwa kakhulu kwezi ezibangela izifo ebantwini.

Ii-Fungi nazo zibangela ukugula. Ezi ntsholongwane zine-nucleus yaye ziba ngathi yimethi eyenziwe ngemicu ephitheneyo. Ezinye zezifo ezidla ngokuzibangela zii-ringworm, ezifana ne-athlete’s foot ne-candidiasis (i-Candida). Izifo eziyingozi ezibangelwa lolu hlobo lwentsholongwane zidla ngokuhlasela abantu abasele bebuthathaka ngenxa yokungondleki, umhlaza, iziyobisi okanye abanesifo esithile esibangelwa yi-virus, esenza ukuba inkqubo yomzimba yokuzikhusela ingasebenzi kakuhle.

[Imifanekiso]

I-“virus” ebangela i-“Ebola”

I-“bacteria” ebizwa ngokuba “yi-Staphylococcus aureus”

I-“protozoan” ebizwa ngokuba “yi-Giardia lamblia”

I-“fungus” ebangela i-“ringworm”

[Inkcazelo]

CDC/C. Goldsmith

CDC/Janice Carr

Courtesy Dr. Arturo Gonzáles Robles, CINVESTAV, I.P.N. México

© Bristol Biomedical Image Archive, University of Bristol

[Umfanekiso okwiphepha 14]

UAlexander Fleming, owenza i-penicillin