Clinical Manifestations a great variety of infections including abscesses, gangrene, cellulitis, bacteremia, pneumonia, peritonitis, bite wounds, and pelvic inflammatory disease. Klinik ko'rinishlari


Tuzilishi, tasnifi va antigen turlari



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Abdukholikov Firdavs Microbiology Theme 1

Tuzilishi, tasnifi va antigen turlari
Anaerob kokklar fiziologik jihatdan xilma-xil guruh bo'lib, yaqinda sezilarli taksonomik o'zgarishlarni boshdan kechirgan. Klinik ahamiyatga ega bo'lgan anaerob gramm-musbat kokklar uchta gramm-musbat avlod ( Peptostreptococcus, Gemella va Streptococcus ) va bir gramm-manfiy jinsda ( Villonella ) uchraydi . Anaerob kokklarning boshqa avlodlari ham mavjud, ammo ular klinik namunalardan kamdan-kam hollarda ajratiladi. Hamma anaerob kokklar qattiq anaerob sharoitlarni talab qilmaydi; masalan, Streptococcus intermedius shtammlariaerotolerant bo'lib, kislorod tarangligi pasayganda o'sishi mumkin. Anaerob kokklar proteolitik yoki saxarolitik yoki ikkalasi ham bo'lishi mumkin. Ular oddiy qandlar va aminokislotalarning fermentatsiyasi natijasida turli xil qisqa zanjirli uchuvchi yog 'kislotalari (ya'ni, sirka, propion, butirik, kaproik va sut kislotalari) hosil qiladi. P magnus ham , P anaerobius ham turlarga xos hujayra devori antijenlariga ega; boshqa anaerob kokklarda turga xos antijenler hali aniqlanmagan. Peptostreptokokklar va streptokokklar klinik jihatdan eng muhim avlod bo'lib, P magnus eng ko'p uchraydigan klinik izolat hisoblanadi.
The anaerobic gram-positive cocci are difficult to speciate, but a few biochemical tests can be helpful. P anaerobius is the only species susceptible to sodium polyanethol sulfonate (SPS). P asaccharolyticus and P hydrogenalis are both indole positive, but alkaline phosphatase negative and positive, respectively. Of the indole-negative butyric acid producers, P tetradius is strongly saccharolytic and urease-positive, while P prevotii is weakly saccharolytic and usually urease-negative. P magnus and P micros are similar biochemically and are distinguished primarily on the basis of cell size and alkaline phosphatase reaction. The three prominent species of anaerobic cocci that are strongly saccharolytic and produce large amounts of lactic acid include S intermedius, S constellatus, G morbillorum. These latter species are either aerotolerant or become aerotolerant upon passage on laboratory media. Obligate anaerobic species in the genus Streptococcus are only rarely isolated from clinical specimens, but may be found in human feces, as can other genera of anaerobic gram-positive cocci.
Three genera of anaerobic gram-negative cocci can be found in human fecal flora: Veillonella, Acidominococcus, and MegosphoraVeillonella is considered the only clinically significant genus and V parvula is the species most frequently isolated from clinical specimens. Veillonella can be presumptively identified by the red fluorescence of colonies under ultraviolet light. This fluorescence is lost rapidly on exposure to oxygen.
Anaerob gramm-musbat kokklarni aniqlash qiyin, ammo bir nechta biokimyoviy testlar foydali bo'lishi mumkin. P anaerobius natriy polianetol sulfonatga (SPS) sezgir bo'lgan yagona turdir. P asaccharolyticus va P hydrogenalis ikkalasi ham indol musbat, lekin ishqoriy fosfataza mos ravishda manfiy va ijobiydir. Indol-manfiy butirik kislota ishlab chiqaruvchilardan P tetradius kuchli saxarolitik va ureaza-musbat, P prevotii esa zaif saxarolitik va odatda ureaza-manfiy. P magnus va P mikrobiokimyoviy jihatdan o'xshash va birinchi navbatda hujayra hajmi va ishqoriy fosfataza reaktsiyasi asosida ajralib turadi. Kuchli saxarolitik va ko'p miqdorda sut kislotasi ishlab chiqaradigan anaerob kokklarning uchta mashhur turiga S intermedius, S constellatus, G morbillorum kiradi . Bu oxirgi turlar aerotolerant yoki laboratoriya muhitida o'tganda aerotolerant bo'lib qoladi. Streptococcus jinsidagi majburiy anaerob turlari klinik namunalardan kamdan-kam hollarda ajratiladi, lekin anaerob gram-musbat kokklarning boshqa avlodlari kabi inson najasida ham topilishi mumkin.
Inson najas florasida anaerob gramm-manfiy kokklarning uchta avlodini topish mumkin: Veillonella, Acidominococcus va Megosphora . Veillonella yagona klinik ahamiyatga ega jins hisoblanadi va V parvula klinik namunalardan eng ko'p ajratilgan tur hisoblanadi. Veillonella ultrabinafsha nurlar ostida koloniyalarning qizil floresansi bilan taxminiy ravishda aniqlanishi mumkin. Bu lyuminestsent kislorod ta'sirida tezda yo'qoladi.

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