Distribution of yeast isolates from invasive infections and their in vitro susceptibility to antifungal agents: evidence from 299 cases in a 3-year (2010 to 2012) surveillance study.

Invasive yeast infections cause significant morbidity and mortality. Surveillance for the infection is necessary to detect trends in species distribution and antifungal resistance. We performed this retrospective study of yeast infection at Jinling Hospital, Nanjing in China, from year of 2010 to 2012. A total of 341 yeast isolates were obtained from patients with invasive infections in the period. Among these isolates, Candida spp. comprised of the highest percentage of yeast strains (91.8 %), followed by Cryptococcus neoformans (5.9 %) and other non-Candida yeast strains (2.3 %). Bloodstream isolates made up 41.3 % of yeast strains and the isolates from CVC made up 17.3 %. Among Candida spp., C. albicans was the most common species identified from non-blood clinical specimens (42.9 %), but appeared in only 20.8 % of blood isolates (P < 0.001). C. tropicalis was the most prevalent Candida species in the blood samples (28.5 %). Candida spp. was mainly isolated from specimens of the ICU patients, while C. neoformans was mainly isolated from specimens in medical wards. Resistance to FLC occurred in 3.7 % of C. albicans, 9.9 % of C. tropicalis, 74.0 % of C. glabrata, and 4.4 % of C. parapsilosis. Most (>92 %) isolates of C. albicans, C. tropicalis, C. parapsilosis, and C. neoformans strains were susceptible to VRC; However, 26.7 % of isolates of C. glabrata were VRC resistant.

In vitro susceptibilities of yeast species to fluconazole and voriconazole as determined by the 2010 National China Hospital Invasive Fungal Surveillance Net (CHIF-NET) study.

We conducted active, laboratory-based surveillance for isolates from patients with invasive infections across China from August 2009 to July 2010. DNA sequencing methods were used to define species, and susceptibility to fluconazole and voriconazole was determined by the Clinical and Laboratory Standards Institute M44-A2 disk diffusion method but using up-to-date clinical breakpoints or epidemiological cutoff values. Candida spp. made up 90.5% of the 814 yeast strains isolated, followed by Cryptococcus neoformans (7.7%) and other non-Candida yeast strains (1.7%). Bloodstream isolates made up 42.9% of the strains, isolates from ascitic fluid made up 22.1%, but pus/tissue specimens yielded yeast strains in <5% of the cases. Among the Candida isolates, Candida albicans was the most common species from specimens other than blood (50.1%) but made up only 23% of the bloodstream isolates (P < 0.001). C. parapsilosis complex species were the most common Candida isolates from blood (33.2%). Uncommon bloodstream yeast strains included Trichosporon spp., C. pelliculosa, and the novel species C. quercitrusa, reported for the first time as a cause of candidemia. Most (>94%) of the isolates of C. albicans, C. tropicalis, and the C. parapsilosis complex were susceptible to fluconazole and voriconazole, as were all of the Trichosporon strains; however, 12.2% of the C. glabrata sensu stricto isolates were fluconazole resistant and 17.8% had non-wild-type susceptibility to voriconazole. Seven C. tropicalis strains were cross-resistant to fluconazole and voriconazole; six were from patients in the same institution. Resistance to fluconazole and voriconazole was seen in 31.9% and 13.3% of the uncommon Candida and non-Candida yeast strains, respectively. Causative species and azole susceptibility varied with the geographic region. This study provided clinically useful data on yeast strains and their antifungal susceptibilities in China.

Immunoproteomics based identification of thioredoxin reductase GliT and novel Aspergillus fumigatus antigens for serologic diagnosis of invasive aspergillosis.

BACKGROUND: There has been a rising incidence of invasive aspergillosis (IA) in critically ill patients, even in the absence of an apparent predisposing immunodeficiency. The diagnosis of IA is difficult because clinical signs are not sensitive and specific, and serum galactomannan has relatively low sensitivity in this group of patients. Therefore, more prompt and accurate disease markers for early diagnosis are needed. To establish disease markers demands a thorough knowledge of fungal antigens which may be detected in the serum or other body fluids of patients. Herein we report novel immunodominant antigens identified from extracellular proteins of Aspergillus fumigatus. RESULTS: Extracellular proteins of A. fumigatus were separated by two-dimensional electrophoresis (2-DE) and probed with the sera from critically ill patients with proven IA. The immunoreactive protein spots were identified by MALDI-TOF mass spectrometry (MALDI-TOF -MS). Forty spots from 2DE gels were detected and 17 different proteins were identified as immunogenic in humans. Function annotation revealed that most of these proteins were metabolic enzymes involved in carbohydrate, fatty acid, amino acid, and energy metabolism. One of the proteins, thioredoxin reductase GliT (TR), which showed the best immunoactivity, was analyzed further for secretory signals, protein localization, and homology. The results indicated that TR is a secretory protein with a signal sequence exhibiting a high probability for secretion. Furthermore, TR did not match any human proteins, and had low homology with most other fungi. The recombinant TR was recognized by the sera of all proven IA patients with different underlying diseases in this study. CONCLUSIONS: The immunoreactive proteins identified in this study may be helpful for the diagnosis of IA in critically ill patients. Our results indicate that TR and other immunodominant antigens have potential as biomarkers for the serologic diagnosis of invasive aspergillosis.

[A study of the histopathological characteristics of nontuberculous mycobacteria lymphadenitis].

OBJECTIVE: To describe the distinctive histopathological changes of nontuberculous mycobacteria lymphadenitis. METHODS: An experimental animal model of nontuberculous mycobacteria lymphadenitis was established and the histopathological changes were observed by light microscope. The paraffin imbedded tissue samples from patients suspected of having lymphoid tuberculosis were also detected by triplex polymerase chain reaction and studied by light microscope. RESULTS: The distinctive histopathological changes of nontuberculous mycobacteria lymphadenitis in the animal model were as follows: (1) Tubercular granuloma formation in lymph nodes which were infected with nontuberculous mycobacteria. Coagulation necrosis was located at the center of the granuloma, and the necrosis looked different from the caseation necrosis caused by mycobacterium tuberculosis. Many neutrophils and their nuclear debris were distributed over the necrosis area. Surrounding the central necrosis area, many epithelioid cells, lymph cells and mononuclear cells could be found. The periphery of the granuloma was surrounded by fibrous tissues. Langhans giant cells could be found in the granuloma and outside the granuloma, while these cells were usually found only in the granuloma of tuberculosis. (2) Serpiginous necrosis was found in the lymph nodes infected with nontuberculous mycobacteria. Many neutrophils and their nuclear debris were distributed over the necrosis area. Around the central necrosis area, many epithelioid cells, lymph cells and mononuclear cells could be found. The fibrous tissues were in the borderline. (3) Star-like necrosis and aristiform necrosis were also found in lymph nodes infected with nontuberculous mycobacteria. A paraffin imbedded tissue sample was detected by triplex polymerase chain reaction and the diagnosis of nontuberculous mycobacteria lymphadenitis was made. In this sample, epithelioid granuloma, serpiginous necrosis and star-like necrosis were found. Neutrophils and their nuclear debris were found distributed over the necrosis area, while epithelioid cells, lymph cells, mononuclear cells and Langhans giant cells were found around the central necrosis area. Polar arrangement of the nuclei of epithelioid cells was evident. The lesion was surrounded by fibrous and collagen tissues. CONCLUSION: Serpiginous, star-like and aristiform necrosis were the distinctive histopathological changes of nontuberculous mycobacteria lymphadenitis. Neutrophils and their nuclear debris were abundant over the necrosis area. Polar arrangement of the nuclei of epithelioid cells was also a distinctive histopathological manifestation.

[Genotype distribution of extended-spectrum beta-lactamases and AmpC beta-lactamases produced in Escherichia coli isolated from men with urinary infection].

OBJECTIVE: To study the genotype distribution of extended-spectrum p-lactamases (ESBLs) and AmpC p-lactamases produced in E. coli isolated from men with urinary infection in Nanjing. METHODS: Organisms of clinical infection were identified by automatic microbial system (Vitek-32). ESBLs were detected by disk diffusion confirmatory test, and ESBLs and AmpC p-lactamases by three-dimensional extract test (TDET) , the presence of plasmid-mediated ESBLs and ampC genes determined by PCR, and conjugal transfer assays of the ampC resistance determinants carried out by a broth mating procedure. RESULTS: ESBLs were produced in 24. 6% (46/187) of the E. coli and the 46 E. coli isolates showed p-lactamase activity in TDET, 3 positive for both ESBLs and AmpC beta-lactamases and 43 for ESBLs only. Forty-four of the 46 isolates were shown by PCR to contain at least one of the genes blaTEM, blaOXA, bla(CTX-M), but no blaSHA. AmpC specific amplication products were observed in 3 of the 46 isolates, of which 2 were of CIT type, and 1 of DHA type. All of the 3 transconjugants transferred the plasmids harbouring ampC genes to recipients. CONCLUSION: CTX-M is the most common genotype in plasmid-mediated ESBLs produced by E. coli isolated from men with urinary infection in Nanjing. Present findings indicate that AmpC-producing E. coli are present in this hospital, and ampC-encoding plasmids are transferable.

[Distribution and resistance trends of pathogens from urinary tract infections and impact on management].

OBJECTIVE: To assess the bacterial profile and pattern of antibiotic resistance of urinary tract infections (UTIs) pathogens and to determine its clinical impact on management. METHODS: Midstream urine samples were submitted for culture from 1998 to 2002, and 798 isolates were obtained for antimicrobial susceptibility testing including amikacin (AMK), ampicillin (AMP), cefzolin (CFZ), cefuroxime (CXM), ceftriaxone (CRO), ceftaxime (CTX), ceftazidime (CAZ), nalidixoc acid (NAL), ciprofloxacin (CIP), trimethoprim/sulfamethoxazole (SXT), nitrofurantoin (NIT) for Gram-negative bacteria and oxcillin (OXA), ampicillin (AMP), cefzolin (CFZ), ciprofloxacin (CIP), gentamicin (Gen), vancomycin (VAN), trimethoprim/sulfamethoxazole (SXT), nitrofurantoin (NIT) for Gram-positive cocci. beta-lactamases and ESBLs were tested when needed. RESULTS: Enterobacteriaceae was the most frequently isolated pathogen. Among all the isolates, Escherichia coli accounted for 66.0%, followed by Enterococcus (6.5%), Klebsiella spp. (6.0%), Staphylococcus (5.4%). High resistance rates to CIP (56.0%), SXT (67.0%) and AMP (78.9%) were observed among the E. coli. CIP-resistant E. coli strains are being isolated with increasing frequency. From 1998 to 2002 the incidence of CIP-resistant increased steadily from 46.6% to 59.4%. A higher resistance rate to NAL was apparent. In contrast, NIT displayed a resistance rate of 8.9%, and AMK 4.9%. The ESBLs positive rate was 12.9% among the E. coli and 33.3% among the Klebsiella spp. respectively. A high resistance rate to CIP was also observed among the Staphylococcus (38.1%), Enterococcus (61.5%) and Streptococcus (85.0%), and the beta-lactamases positive rate was 95.2% among the Staphylococcus, but a lower resistance rate to NIT among Staphylococcus (2.4%) and Enterococcus (11.5%). CONCLUSIONS: Resistance rates among common uropathogens continue to evolve and appear to be increasing to many commonly used agents especially to quinolones. Continued surveillance of resistance rates among uropathogens is needed to ensure appropriate recommendations for the treatment of the infections. Currently, the most appropriate agent for the empirical management of UTIs seems to be nitrofurantoin.

Mechanisms of carbapenem resistance in cephalosporin-susceptible Pseudomonas aeruginosa in China.

Twenty-nine Pseudomonas aeruginosa isolates, which are resistant to carbapenems but susceptible to ceftazidime or/and cefepime, were recovered from our hospital from July 2011 to October 2011. The results of Western blotting showed that the OprD was reduced or lost. None of the 29 clinical isolates produced carbapenemases, extended-spectrum ß-lactamases, or Ambler class C ß-lactamases enzymes by the modified 3-dimensional test. The sequencing of oprD for these isolates showed that there are multiple point mutations, large fragment substitutions, deletions, and insertions. It showed that the expression of oprD decreased while mexA and mexX increased by real-time reverse transcriptase-PCR. These results suggested that the loss of OprD and overexpression of mexXY-OprM and mexAB-OprM are associated with carbapenem resistance in cephalosporin-susceptible Pseudomonas aeruginosa.

Antibody specific to thioredoxin reductase as a new biomarker for serodiagnosis of invasive aspergillosis in non-neutropenic patients.

BACKGROUND: Invasive aspergillosis (IA) is an important cause of mortality in critically ill patients, but the diagnosis is difficult as clinical and radiological signs are neither sensitive nor specific. Serum galactomannan (GM) is a useful marker for IA, but exhibits low sensitivity in non-neutropenic patients. In our previous work, strong antibody reactivity to thioredoxin reductase of Aspergillus fumigatus was found in non-neutropenic IA patients. METHODS AND RESULTS: Using recombinant thioredoxin reductase GliT (TR), an antigenic protein secreted by A. fumigatus, as the coating antigen, an enzyme-linked immunosorbent assay (ELISA) for detecting anti-TR antibodies was developed. The antibody response to TR in IA animal models and 42 non-neutropenic patients with culture- and/or histology-documented IA was investigated. The results showed that anti-TR antibody was detectable in rabbit serum 7-9 days after exposure to the fungus. The sensitivity and specificity of the anti-TR antibody assay in patients were 80.9% and 96%, respectively, while the sensitivity of GM in this group of patients was only 52.3%. The specificity of the assay was confirmed by testing the sera from patients infected with other pathogenic fungal species and bacteria.

A case of agonadism associated with y-chromosome rearrangement: cytogenetic and molecular studies.

Testicular regression syndrome (MIM273250) is characterized primarily by absence of gonads in a person of XY karyotype. Phenotypes range from complete female external genitalia (primary or "true" agonadism) to male phenotype with anorchia (testicular regression). Phenotypic differences depend on the stage of embryo development during which testes degenerate. No conclusive mapping can be concluded for the phenotype. We describe a novel case of primary agonadism with a karyotype of 46,X,der(Y)(pter-->q11.23::pter-->p11.31 or p11.2:). Transcriptional analysis revealed little expression of USP9Y and UTY genes on the Y chromosome in our case, which would explain her phenotypes of agonadism with short stature.