OBJECTIVETo explore the feasibility of inducing fungal infection by Cryptococcus neoformans aerosol inhalation in immunosuppressed Balb/c mice.

METHODSTwenty-four Balb/c mice were randomized into cyclophosphamide (CTX) group and control group (n=12). The mice in CTX group were subject to inhalation of Cryptococcus neoformans aerosol prepared using a ultrasonic nebulizer 4 days after intraperitoneal CTX injection, and the control mice received the inhalation only. The leukocyte count and changes in appetite, body weight, and behaviors of the mice were observed after the treatments. On days 3 and 7 after the inoculation, the mice were sacrificed to analyze the fungal counts in brain and lung tissue homogenates and examine the pulmonary pathologies.

RESULTSCTX injection caused lowered appetite and body weight loss in the mice, and significantly reduced the leukocyte counts (2.77∓0.45 vs 8.26∓0.56, P<0.05). At days 3 and 7 after inoculation, the Cryptococci load in the lungs increased obviously in CTX group with a colony-forming unit (CFU) of the lungs of 271.67∓122.22 and 41.67∓0.28, respectively, significantly higher than that in the control group (60.00∓43.36 and 3.00∓5.30, respectively, P<0.05). In CTX group, the CFU was 10.17∓5.42 and 9.17∓6.34 in the peripheral blood and 6.83∓4.92 and 11.00∓5.44 in the brain tissue at days 3 and 7, respectively, whereas no Cryptococci was detected in the peripheral blood or in the brain tissue in the control group. Pathological examination of the lungs revealed destruction of normal alveolar structure in CTX group, with numerous infiltrating inflammatory cells and visible yeast.

CONCLUSIONInhalation of Cryptococcus neoformans aerosol can cause fungal infection in the lungs of immunosuppressed Balb/c mice.

Aerosols ; Animals ; Brain ; microbiology ; Colony Count, Microbial ; Cryptococcosis ; microbiology ; Cryptococcus neoformans ; growth & development ; Disease Models, Animal ; Immunocompromised Host ; Inhalation ; Lung Diseases, Fungal ; microbiology ; Male ; Mice ; Mice, Inbred BALB C ; Ultrasonics

Objective To evaluate the efficacy and drug resistance profiles of nucleosides (NA) retreatment in NA experienced chronic hepatitis B (CHB) patients. Methods Totally 104 NA experienced CHB subjects were enrolled in this study.All these subjects had received at least 3 months NA monotherapy and stopped the treatment,and then received NA retreatment for at least one year.The subjects were divided into three groups according to the following criteria:reached the therapy endpoint of China guideline when they stopped NA-naive treatment (group A,n =39); did not reach the therapy endpoint when they stopped NA-naive treatment but hepatitis B virus (HBV) DNA＜1.0× 103 copy/mL (group B,n=33); and with HBV DNA＞1.0× 103 copy/mL (group C,n=32).The efficacy and drug resistance profiles of retreatment were compared among three groups. The effects of baseline alanine aminotransferase (ALT) levels,HBV DNA levels and HBeAg titers on the retreatment efficacies were analyzed. The mutations of HBV P gene were detected by nested polymerase chain reaction (PCR) and direct sequencing.The data were analyzd by Wilcoxon test and x2 test.Results The time to ALT normalization in patients with baseline ALT＜ 1.3 × upper limit normal (ULN) was shorter than that in patients with ALT≥1.3×ULN (2 months vs 4 months; Z=2.281,P=0.023).The time to virological response in patients with baseline HBV DNA＜5 lg copy/mL was shorter than that in patients with HBV DNA≥5 lg copy/mL (1 month vs 2 months; Z=2.054,P =0.040). The time to virological response and ALT normalization in baseline HBeAg negative were both shorter than those in patients with baseline HBeAg positive patents ( 1 month vs 3 months and 2 months vs 4.5 months,respectively; Z=2.580 and 2.304,respectively; both P＜0.05). The subjects in group A achieved virological response and HBeAg seroconversion after retreatment earlier compared to previous NA-naive therapy ([1.61 ± 1.76] months vs [3.48±4.066]months and [3.38 ± 3.34] months vs [9.92-11.22] months,respectively; Z=-2.854 and-1.094,respectively; both P＜0.05).The cumulative HBeAg seroconversion rate in group A was higher compared to those in group B and group C (80.0％ vs 36.8％ and 37.5％,respectively; x2 =4.368 and 5.100,respectively; both P＜0.05).Thirteen patients developed clinical resistance and four of them developed genotypic resistance proved by PCR direct sequencing.Among the patients retreated with the same regimen as previous in the C group,the cumulative resistance rate was highest compared to group A and B (44％ vs 9％ and 0,respectively; x2 =5.019 and 6.588,respectively;both P＜0.05).No resistance was detected in the 14 patients retreated with combined NA treatment without cross resistance.Conclusions For NA experienced CHB patients who fulfill the indication of antiviral therapy,the retreatment should be started as earlier as possible. Retreatment with NA combination without cross resistance can prevent (reduce) the risk of developing drug resistance.