{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T14:29:25Z","timestamp":1791296965790,"version":"4.1.0"},"reference-count":56,"publisher":"Microbiology Society","issue":"8","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2006,8,1]]},"abstract":"<jats:p><jats:italic>Cryptococcus neoformans<\/jats:italic>is a common cause of meningoencephalitis among AIDS patients. Several<jats:italic>C. neoformans<\/jats:italic>virulence factors have been identified, but the relative importance of particular factors is unknown. This study examined the corrrelation of the virulence of 18<jats:italic>C. neoformans<\/jats:italic>var.<jats:italic>grubii<\/jats:italic>isolates from AIDS patients with the expression of several well-described virulence factors. The LD<jats:sub>50<\/jats:sub>at 15\u2005days after intracranial inoculation of ICR mice was &lt;100\u2005c.f.u. for 22\u200a% of isolates, 100\u20131000 for 28\u200a%, 1000\u201310\u200a000 for 11\u200a% and &gt;20\u200a000 for 39\u200a%. Higher cryptococcal concentrations in brains were noted for isolates with lower LD<jats:sub>50<\/jats:sub>(<jats:italic>P<\/jats:italic>=0.002). In survival studies, no immunocompetent BALB\/c mice (<jats:italic>nu<\/jats:italic>\/\u2212) infected with 3\u00d7LD<jats:sub>50<\/jats:sub>of three virulent isolates (LD<jats:sub>50<\/jats:sub>=62, 99, 1280) survived beyond 23\u2005days, whereas 100\u200a%, 90\u200a% and 90\u200a% of mice infected with 20\u200a000\u2005c.f.u. of three hypovirulent isolates (LD<jats:sub>50<\/jats:sub>&gt;20\u200a000) survived for 60\u2005days (<jats:italic>P<\/jats:italic>&lt;0.0001). Even among BALB\/c nude (<jats:italic>nu<\/jats:italic>\/<jats:italic>nu<\/jats:italic>) mice, survival rates over 60\u2005days were 100\u200a%, 70\u200a% and 50\u200a%, respectively, for the hypovirulent isolates. Growth rate at 37\u200a\u00b0C and capsule size within brains correlated with LD<jats:sub>50<\/jats:sub>by univariate (<jats:italic>P<\/jats:italic>=0.0001 and 0.028, respectively) and multivariate (<jats:italic>P<\/jats:italic>=0.017 and 0.016, respectively) analyses. There was no correlation between LD<jats:sub>50<\/jats:sub>and capsule size<jats:italic>in vitro<\/jats:italic>, phospholipase activity, melanin formation, proteinase activity and fluconazole MIC. In conclusion, AIDS patients are susceptible to infection by<jats:italic>C. neoformans<\/jats:italic>isolates of wide-ranging virulence, including isolates that are markedly hypovirulent. The virulence of a given isolate reflects a composite of factors rather than the contribution of a dominant factor. Growth at 37\u200a\u00b0C and capsule size<jats:italic>in vivo<\/jats:italic>make particularly important contributions.<\/jats:p>","DOI":"10.1099\/mic.0.28798-0","type":"journal-article","created":{"date-parts":[[2006,7,18]],"date-time":"2006-07-18T23:28:04Z","timestamp":1153265284000},"page":"2247-2255","source":"Crossref","is-referenced-by-count":32,"title":["Cryptococcus neoformans var. grubii isolates recovered from persons with AIDS demonstrate a wide range of virulence during murine meningoencephalitis that correlates with the expression of certain virulence factors"],"prefix":"10.1099","volume":"152","author":[{"given":"Cornelius J.","family":"Clancy","sequence":"first","affiliation":[{"name":"VA Medical Center, Gainesville, FL, USA"},{"name":"Department of Medicine, Division of Infectious Diseases, University of Florida College of Medicine, FL, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M. Hong","family":"Nguyen","sequence":"additional","affiliation":[{"name":"VA Medical Center, Gainesville, FL, USA"},{"name":"Department of Medicine, Division of Infectious Diseases, University of Florida College of Medicine, FL, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ruth","family":"Alandoerffer","sequence":"additional","affiliation":[{"name":"University of Texas Health Science Center, and the Audie Murphy Memorial Hospital, San Antonio, TX, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shaoji","family":"Cheng","sequence":"additional","affiliation":[{"name":"Department of Medicine, Division of Infectious Diseases, University of Florida College of Medicine, FL, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kenneth","family":"Iczkowski","sequence":"additional","affiliation":[{"name":"VA Medical Center, Gainesville, FL, USA"},{"name":"Department of Pathology, University of Florida College of Medicine, FL, 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