Evaluation of point mutation detection in Mycobacterium tuberculosis with isoniazid resistance using real-time PCR and TaqMan probe assay.

Rapid methods for diagnosis of Mycobacterium tuberculosis (Mtb) drug resistance and choosing appropriate antibiotic treatment are pivotal. Thirty isoniazid (INH)-resistant and 30 INH-susceptible Mtb isolates were evaluated using minimum inhibitory concentration (MIC) method followed by multiplex real-time PCR (RT-PCR). Amplification refractory mutation system (ARMS) for detection of mutation in 315 codon of katG gene and single-nucleotide polymorphism (SNP) for detection of mutation in -15 (C>T) in the regulatory zone of mabA-inhA were carried out using the TaqMan method. Primers and probe were used for IS6110 region of Mtb as an internal amplification control. The sensitivity and specificity of the RT-PCR TaqMan probe for detection of Mtb complex were 100 %. Detection of INH-resistant Mtb using the ARMS method for KatG had 69 % sensitivity and 100 % specificity. The sensitivity and specificity of SNP in mabA-inhA fragment for detection of INH-resistant Mtb were 53 and 100 %, respectively. Furthermore, considering both regions, the sensitivity of RT-PCR has increased to 75 %. This study revealed that the qPCR-TaqMan method can be used as a standard tool for diagnosis of Mtb. Moreover, ARMS and SNP RT-PCR TaqMan methods can be used as rapid screening methods for detection of INH-resistant Mtb.

Hypersensitivity to rabbit antithymocyte globulin in an islet transplant recipient: a case report.

OBJECTIVE: The aim was to describe a case of hypersensitivity to rabbit antithymocyte globulin (rATG) occurring in the context of islet transplantation. METHODS: A 36-year-old woman with type 1 diabetes was admitted for islet transplantation. rATG was administered the first day (1.5 mg/kg) with methylprednisolone (2 mg/kg), and on the second day (1.5 mg/kg) without glucocorticoid to avoid potential toxicity to the anticipated islet transplant. RESULTS: At the end of the rATG infusion on the second day she developed hives over her face, chest, and back and tender erythema at her intravenous site (Arthus reaction). Islet transplantation was not performed. She reported exposure to a pet rabbit for 2 years in childhood. Overnight, fever developed and the rash evolved into an erythematous morbilliform eruption affecting the torso. Serum high-sensitivity C-reactive protein (hsCRP) and the erythrocyte sedimentation rate (ESR) were elevated; serum complements C3 and C4 were normal. She received prednisone (50 mg) with subsequent resolution of the rash. Nine days after her initial reaction, she developed a recurrence of the rash and fever with arthralgias; levels of C3 and C4 had fallen. Methylprednisolone (125 mg, twice) was required for symptom improvement, and was gradually tapered as prednisone over the next 4 weeks with resolution of the complement, ESR, and hsCRP abnormalities. Five months after the initial attempt at islet transplantation, she returned to receive 7,879 IE/kg via portal vein infusion under basiliximab, etanercept, tacrolimus, and sirolimus immunosuppression and has required no to low-dose (0.1 U/kg/d) insulin to maintain near-normal glycemic control for > 12 months after transplantation. CONCLUSIONS: Our patient's initial hypersensitivity reaction to rATG was followed by immune-complex type 3 hypersensitivity (serum sickness) requiring high-dose glucocorticoids. Canceling the initial islet infusion proved to be wise, and the patient subsequently did well with islet transplantation under an alternative induction agent.

Induction of diabetes in nonhuman primates by means of temporary arterial embolization and selective arterial injection of streptozotocin.

PURPOSE: To develop and assess a technique for induction of C peptide-negative diabetes in adult nonhuman primates in preparation for preclinical investigation of type 1 diabetes treatments. MATERIALS AND METHODS: First, temporary embolization of the hepatic and gastric arteries was performed in 14 adult nonhuman primates (six cynomolgus, five rhesus, and three pigtail macaques). After embolization was confirmed with angiography, streptozotocin was injected at a dose of 50-70 mg/kg into the celiac artery and branches supplying the pancreas. The macaques then were given intravenous injections of arginine and glucose, and blood levels of insulin and C peptide were measured with an enzyme-linked immunosorbent assay to determine whether diabetes had been induced. RESULTS: All but one of the macaques developed persistent long-term C peptide-negative diabetes after the streptozotocin injection. One macaque did not develop diabetes after the initial injection and was given a second dose of streoptozotocin, which did induce diabetes. None of the macaques showed any symptoms of hepatic or renal injury, and only one died (of gastric dilatation 5 days after the procedure). CONCLUSION: Streptozotocin injection after temporary embolization of the hepatic and gastric arteries is a safe and reproducible method for inducing C peptide-negative diabetes in adult nonhuman primates in preparation for preclinical investigation of type 1 diabetes treatments.