Clonality despite sex: the evolution of host-associated sexual neighborhoods in the pathogenic fungus Penicillium marneffei.

Molecular genetic approaches typically detect recombination in microbes regardless of assumed asexuality. However, genetic data have shown the AIDS-associated pathogen Penicillium marneffei to have extensive spatial genetic structure at local and regional scales, and although there has been some genetic evidence that a sexual cycle is possible, this haploid fungus is thought to be genetically, as well as morphologically, asexual in nature because of its highly clonal population structure. Here we use comparative genomics, experimental mixed-genotype infections, and population genetic data to elucidate the role of recombination in natural populations of P. marneffei. Genome wide comparisons reveal that all the genes required for meiosis are present in P. marneffei, mating type genes are arranged in a similar manner to that found in other heterothallic fungi, and there is evidence of a putatively meiosis-specific mutational process. Experiments suggest that recombination between isolates of compatible mating types may occur during mammal infection. Population genetic data from 34 isolates from bamboo rats in India, Thailand and Vietnam, and 273 isolates from humans in China, India, Thailand, and Vietnam show that recombination is most likely to occur across spatially and genetically limited distances in natural populations resulting in highly clonal population structure yet sexually reproducing populations. Predicted distributions of three different spatial genetic clusters within P. marneffei overlap with three different bamboo rat host distributions suggesting that recombination within hosts may act to maintain population barriers within P. marneffei.

Monitoring of peptide-specific and gamma interferon-productive T cells in patients with active and convalescent tuberculosis using an enzyme-linked immunosorbent spot assay.

To establish a high-efficiency gamma interferon-specific enzyme-linked immunosorbent spot assay (IFN-γ ELISPOT assay) for detection of tuberculosis (TB), peptides (E6, E7, and C14) and peptide mixtures (E6 plus E7 and E6 plus E7 plus C14) were used to monitor peripheral blood (PBL) samples from patients with pulmonary TB (PTB), as well as control samples. The positive detection rates of the five IFN-γ ELISPOT assays were 78.38%, 74.86%, 55.83%, 90.43%, and 91.51%, respectively, and there were similar detection rates between the two combined peptide mixture IFN-γ ELISPOT assays and the tuberculin skin test (TST) (90.62% versus 95.59%). No significant difference was found between the detection rates of the two combined peptide mixture IFN-γ ELISPOT assays and the T-SPOT.TB assay for 86 patients with PTB (P > 0.05), but the median number of spot-forming cells/10(6) cells (SFP value) for positive results was higher by the former than by the latter assay (P < 0.05). In contrast, the 29.93% positive detection rate and median SFP value of 482 by the two combined peptide mixture IFN-γ ELISPOT assays were significantly higher than the corresponding values of 14.29% and 152 by T-SPOT.TB assay for the same 147 community donors (P < 0.05). For nine PTB patients tracked, the SFP value of 7 for the two peptide mixture IFN-γ ELISPOT assays began to decrease from the second month after regular treatment. A relatively low, almost normal, SFP level was reached and maintained after the third or fourth month. Two in-house IFN-γ ELISPOT assays and the T-SPOT.TB assay could reduce the false-positive and false-negative detection rates of TST and sputum acid-fast staining. Therefore, these two combined peptide mixture IFN-γ ELISPOT assays have a potential advantage, beyond their greater specificity and sensitivity, for use in screening and detection of active TB infection (TBI) and latent TB infection (LTBI) in China.

Radiologic diagnosis for AIDS patients complicated with candidal esophagitis.

BACKGROUND: Candidal esophagitis is the primary infection among all digestive tract opportunistic ones in acquired immunodeficiency syndrome (AIDS) cases. X-ray manifestation reports of it are still rare. This study aimed to conduct a retrospective analysis on the X-ray data of 6 AIDS cases complicated with candidal esophagitis, and to study the X-ray characteristics of it combined with the findings from gastroscopy. METHODS: Among 6 cases in this series, all cases were confirmed by Shenzhen Center for Disease Control and Prevention (CDC) to be HIV positive and all of them had CD4 cell counts less than 150 × 10(6)/L. All cases underwent X-ray and gastroscopy, and mycelium were found in the mucous membrane of the esophagus. RESULTS: In this series, the findings of the X-ray were as follows: (1) Affected areas: Four cases in the whole esophagus, 2 cases in the middle and lower part of esophagus; (2) Abnormal motivity: Six cases had decreased tension, loose walls, weakened peristalsis, decreased number of peristalsis waves and delayed emptying of barium; (3) Abnormal contour: Six cases had the sign of "decorative border" or "brush", two cases had narrowed canal; (4) Abnormal membrane and "cobblestone sign": Six cases had thickened membrane and "cobblestone sign" on the surface of the abnormal membrane. The hyperemia of mucosa was covered tightly with yellow-white pseudomembrane spots. This was in accordance with the small cobblestone-like filling defect found by X-ray. CONCLUSIONS: If the AIDS cases have dysphagia, and X-ray shows that more than two sections of the esophagus are affected, with decreased motility, the walls in the sign of "brush" or "decorative edges", thickened membrane with "cobblestone sign", candidal esophagitis is highly possible.