Passive surveillance for azole-resistant Aspergillus fumigatus, United States, 2011-2013.

Emergence of Aspergillus fumigatus strains containing mutations that lead to azole resistance has become a serious public health threat in many countries. Nucleotide polymorphisms leading to amino acid substitutions in the lanosterol demethylase gene (cyp51A) are associated with reduced susceptibility to azole drugs. The most widely recognized mutation is a lysine to histidine substitution at aa 98 (L98H) and a duplication of the untranscribed promoter region, together known as TR34/L98H. This mechanism of resistance has been reported in Europe, Asia, and the Middle East, and is associated with resistance to all azole drugs and subsequent treatment failures. To determine whether isolates with this mutation are spreading into the United States, we conducted a passive surveillance-based study of 1,026 clinical isolates of A. fumigatus from 22 US states during 2011-2013. No isolates harboring the TR34/L98H mutation were detected, and MICs of itraconazole were generally low.

Epidemiology of community-onset candidemia in Connecticut and Maryland.

BACKGROUND: Almost one-third of patients with bloodstream infections with Candida species (candidemia) have onset of disease that occurs outside of the hospital or < or = 2 days after hospital admission (i.e., community-onset candidemia). We compared the characteristics of patients who developed candidemia by the timing of onset of infection. METHODS: Incident episodes of candidemia were identified through active, population-based surveillance in Connecticut and in Baltimore and Baltimore County, Maryland, during 1 October 1998-30 September 2000. The molecular subtypes of a sample of 45 Candida parapsilosis isolates were evaluated using Southern blots hybridized with the complex probe Cp3-13. RESULTS: Overall, 356 (31%) of the 1143 incident episodes of candidemia were classified as community-onset disease (occurring < or = 2 days after hospital admission), and 132 (37%) were caused by Candida albicans, 89 (25%) were caused by Candida glabrata, 57 (16%) were caused by C. parapsilosis, and 53 (15%) were caused by Candida tropicalis. Community-onset disease was less likely to be associated with concurrent immunosuppressive therapy, recent surgery, or use of a central venous catheter, compared with inpatient disease. Among patients with community-onset disease, the median time from blood culture to initiation of antifungal treatment was 2.7 days, the 30-day case-fatality rate was 26%, and 262 patients (75%) had been hospitalized at least once in the previous 3 months. Although there were few differences between patients with very recent hospitalization (in the previous 1 month), less recent hospitalization (previous 1-3 months), and no documented past hospitalization, C. parapsilosis was more frequently associated with community-onset disease as hospitalization became more distant. C. parapsilosis strains tended to be unique to the patient, with little similarity found between strain types, on the basis of epidemiologic classification of patients. CONCLUSION: We report that community-onset candidemia is common and occurs in patients with extensive contact with the health care system. Disease caused by C. parapsilosis tends to involve unique strains.

Evaluation of the status of laboratory practices and the need for continuing education in medical mycology.

A survey to determine the need for training in medical mycology was sent to 605 US laboratories. Training needs were determined by comparing actual laboratory mycology practices with recommended practices, documenting the extent of mycology training reported by employees, and asking respondents to specify the fungi they considered most difficult to identify. The response rate was 56.7% (with only 316 laboratories providing sufficient information). Results showed a large degree of interlaboratory variation in practices and suggested that more judicious practices could lower costs and improve clinical relevance. Only 55.6% of laboratories reported that at least 1 employee attended a formal mycology continuing education program in the 4 years before the survey. Species of dermatophytes, dematiaceous fungi, and non-Candida yeasts were the most difficult to identify. Training may be needed in basic isolation procedures and in advanced topics such as identification of problematic molds and yeasts and antifungal susceptibility testing. Educators should consider clinical relevance and cost-containment without sacrificing quality when designing courses. Support for additional mycology training may improve if hospital and laboratory administrators are alerted to potential dangers and costs involved in treating patients with invasive fungal infections.

Genotyping of Candida parapsilosis from three neonatal intensive care units (NICUs) using a panel of five multilocus microsatellite markers: broad genetic diversity and a cluster of related strains in one NICU.

Candida parapsilosis (CP) (n = 40) isolated from an unselected patient population in the neonatal intensive care units (NICUs) of three US hospitals were collected over periods of 3.5-9 years. Two previously published microsatellite markers and three additional trinucleotide markers were used to produce multiplex genotypes, which revealed broad strain diversity among the NICU isolates with a combined index of discrimination (D) = 0.997. A cluster of eight related CP strains from four infants in a single NICU was observed. An extended collection of 24 CP isolates from the general population of that hospital showed that the cluster of NICU isolates was related to three isolates from general hospital patients. This microsatellite marker set is suitable to investigate clusters of colonizing and infecting strains of CP.

Competitive binding inhibition enzyme-linked immunosorbent assay that uses the secreted aspartyl proteinase of Candida albicans as an antigenic marker for diagnosis of disseminated candidiasis.

The secreted aspartyl proteinases (Saps) of Candida albicans have been implicated as virulence factors associated with adherence and tissue invasion. The potential use of proteinases as markers of invasive candidiasis led us to develop a competitive binding inhibition enzyme-linked immunosorbent assay (ELISA) to detect Sap in clinical specimens. Daily serum and urine specimens were collected from rabbits that had been immunosuppressed with cyclophosphamide and cortisone acetate and infected intravenously with 10(7) C. albicans blastoconidia. Disseminated infection was confirmed by organ culture and histopathology. Although ELISA inhibition was observed when serum specimens from these rabbits were used, more significant inhibition, which correlated with disease progression, occurred when urine specimens were used. Urine collected as early as 1 day after infection resulted in significant ELISA inhibition (mean inhibition +/- standard error [SE] compared with preinfection control urine, 15.7% +/- 2.7% [P < 0.01]), and inhibition increased on days 2 through 5 (29.4% +/- 4.8% to 44.5% +/- 3.5% [P < 0.001]). Urine specimens from immunosuppressed rabbits infected intravenously with Candida tropicalis, Candida parapsilosis, Candida krusei, Cryptococcus neoformans, Aspergillus fumigatus, or Staphylococcus aureus were negative in the assay despite culture-proven dissemination. Nonimmunosuppressed rabbits receiving oral tetracycline and gentamicin treatment were given 2 x 10(8) C. albicans blastoconidia orally or intraurethrally to establish colonization of the gastrointestinal tract or bladder, respectively, without systemic dissemination; urine specimens from these rabbits also gave negative ELISA results. Dissemination to the kidney and spleen occurred in one rabbit challenged by intragastric inoculation, and urine from this rabbit demonstrated significant inhibition in the ELISA (mean inhibition +/- SE by day 3 after infection, 32.9% +/- 2.7% [P < 0.001]). The overall test sensitivity was 83%, the specificity was 92%, the positive predictive value was 84%, the negative predictive value was 91%, and the efficiency was 89% (166 urine samples from 33 rabbits tested). The specificity, positive predictive value, and efficiency could be increased to 97, 95, and 92%, respectively, if at least two positive test results were required for a true positive designation. The ELISA was sensitive and specific for the detection of Sap in urine specimens from rabbits with disseminated C. albicans infection, discriminated between colonization and invasive disease, reflected disease progression and severity, and has the potential to be a noninvasive means to diagnose disseminated candidiasis.

Persistence of oropharyngeal Candida albicans strains with reduced susceptibilities to fluconazole among human immunodeficiency virus-seropositive children and adults in a long-term care facility.

Nineteen oropharyngeal Candida albicans isolates from six children and seven adults living with AIDS at the Russia AIDS Centre, Moscow, from 1990 to 1998 were selected for molecular typing. Two fluconazole-resistant C. albicans genotypes were identified from a child who contracted human immunodeficiency virus infection during the Elista Hospital outbreak in the Kalmyk Republic in 1989. Highly related strains were observed 4 years later in the oral lesions and colonization of two patients and a health care worker. There may be a tendency for persons who are living with AIDS in a long-term care facility and who receive fluconazole therapy for oropharyngeal candidiasis to harbor and spread fluconazole-resistant C. albicans strains.