Candida parapsilosis is the second or third most common cause of candidemia in many countries. The Infectious Diseases Society of America recommends fluconazole as the primary therapy for C. parapsilosis candidemia. Although the rate of fluconazole resistance among C. parapsilosis isolates is low in most U.S. institutions, the resistance rate can be as high as 7.5%. This study was designed to assess the mechanisms of fluconazole resistance in 706 incident bloodstream isolates from U.S. hospitals. We sequenced the ERG11 and MRR1 genes of 122 C. parapsilosis isolates with resistant (30 isolates; 4.2%), susceptible dose-dependent (37 isolates; 5.2%), and susceptible (55 isolates) fluconazole MIC values and used real-time PCR of RNA from 17 isolates to investigate the regulation of MDR1. By comparing these isolates to fully fluconazole-susceptible isolates, we detected at least two mechanisms of fluconazole resistance: an amino acid substitution in the 14-␣-demethylase gene ERG11 and overexpression of the efflux pump MDR1, possibly due to point mutations in the MRR1 transcription factor that regulates MDR1. The ERG11 single nucleotide polymorphism (SNP) was found in 57% of the fluconazole-resistant isolates and in no susceptible isolates. The MRR1 SNPs were more difficult to characterize, as not all resulted in overexpression of MDR1 and not all MDR1 overexpression was associated with an SNP in MRR1. Further work to characterize the MRR1 SNPs and search for overexpression of other efflux pumps is needed.
Background Cryptococcus gattii infections are being reported in the United States (US) with increasing frequency. Initially, US reports were primarily associated with an ongoing C . gattii outbreak in the Pacific Northwest (PNW) states of Washington and Oregon, starting in 2004. However, reports of C . gattii infections in patients from other US states have been increasing since 2009. Whether this is due to increasing frequency of disease, greater recognition within the clinical community, or both is currently unknown.Methodology/Principal FindingsDuring 2005–2013, a total of 273 C . gattii isolates from human and veterinary sources in 16 US states were collected. Of these, 214 (78%) were from the Pacific Northwest (PNW) and comprised primarily the clonal C . gattii genotypes VGIIa (64%), VGIIc (21%) and VGIIb (9%). The 59 isolates from outside the PNW were predominantly molecular types VGIII (44%) and VGI (41%). Genotyping using multilocus sequence typing revealed small clusters, including a cluster of VGI isolates from the southeastern US, and an unrelated cluster of VGI isolates and a large cluster of VGIII isolates from California. Most of the isolates were mating type MATα, including all of the VGII isolates, but one VGI and three VGIII isolates were mating type MATa .Conclusions/SignificanceWe provide the most comprehensive report to date of genotypic diversity of US C . gattii isolates both inside and outside of the PNW. C . gattii may have multiple endemic regions in the US, including a previously-unrecognized endemic region in the southeast. Regional clusters exist both in California and the Southeastern US. VGII strains associated with the PNW outbreak do not appear to have spread substantially beyond the PNW.
Male prison inmates within 2 weeks of release were recruited to evaluate a prerelease HIV prevention intervention. A total of 414 inmates were randomly assigned to receive the intervention or to a comparison group. All participants completed a face-to-face survey at baseline; high rates of preincarceration at-risk behavior were reported. Follow-up telephone surveys were completed with 43% of participants; results support the effectiveness of the prerelease intervention. Men who received the intervention were significantly more likely to use a condom the first time they had sex after release from prison and also were less likely to have used drugs, injected drugs, or shared needles in the first 2 weeks after release from prison. Implications for the development, implementation, and evaluation of prison-based HIV prevention programs are discussed.
; South Texas Veterans Health Care System, San Antonio, Texas, USA e The in vitro activities of the novel fungal Cyp51 inhibitor VT-1129 were evaluated against a large panel of Cryptococcus neoformans and Cryptococcus gattii isolates. VT-1129 demonstrated potent activities against both Cryptococcus species as demonstrated by low MIC 50 and MIC 90 values. For C. gattii, the in vitro potency was maintained against all genotypes. In addition, significantly lower geometric mean MICs were observed for VT-1129 than for fluconazole against C. neoformans, including isolates with reduced fluconazole susceptibility.
Cryptococcus neoformans is an environmentally ubiquitous fungal pathogen that primarily causes disease in people with compromised immune systems, particularly those with advanced AIDS. There are estimated to be almost 1 million cases per year of cryptococcal meningitis in patients infected with human immunodeficiency virus, leading to over 600,000 annual deaths, with a particular burden in sub-Saharan Africa. Amphotericin B (AMB) and fluconazole (FLC) are key components of cryptococcal meningitis treatment: AMB is used for induction, and FLC is for consolidation, maintenance and, for occasional individuals, prophylaxis. However, the results of standard antifungal susceptibility testing (AFST) for AMB and FLC do not correlate well with therapeutic outcomes and, consequently, no clinical breakpoints have been established. While a number of explanations for this absence of correlation have been proffered, one potential reason that has not been adequately explored is the possibility that the physiological differences between the in vivo infection environment and the in vitro AFST environment lead to disparate drug susceptibilities. These susceptibility-influencing factors include melanization, which does not occur during AFST, the size of the polysaccharide capsule, which is larger in infecting cells than in those grown under normal laboratory conditions, and the presence of large polyploid "titan cells," which rarely occur under laboratory conditions. Understanding whether and how C. neoformans differentially expresses mechanisms of resistance to AMB and FLC in the AFST environment compared to the in vivo environment could enhance our ability to interpret AFST results and possibly lead to the development of more applicable testing methods.
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