Transfer of an ampicillin resistance gene between two Escherichia coli strains in the bowel microbiota of an infant treated with antibiotics

OBJECTIVES: To investigate the presumed acquisition of ampicillin resistance by an Escherichia coli strain residing in the gut of an infant. METHODS: E. coli strains were quantified in faecal samples obtained at regular intervals from an infant followed from birth to 12 months of age and their resistance profiles were determined. beta-Lactamases were identified by isoelectric focusing and genes by PCR followed by DNA sequencing. Plasmids were characterized by restriction fragment analysis and Southern-blot hybridization, and tested for conjugative transfer. RESULTS: The infant carried two E. coli strains, termed 29A and 29B, simultaneously in the microbiota during the first month of life. All isolates of 29A were resistant to ampicillin, whereas strain 29B, which was initially ampicillin susceptible, acquired resistance following treatment of the infant with ampicillin/amoxicillin because of urinary tract infection. Acquisition of resistance by strain 29B was associated with acquisition of a bla(TEM-1b)-encoding plasmid, pNK29, which was also present in strain 29A. Transfer of plasmid pNK29 could be replicated by conjugation from strain 29A to strain 29B in vitro. Strain 29A also adapted to ampicillin treatment by mutation of the bla(TEM-1b) promoter gene to yield a higher level of resistance. CONCLUSIONS: This is an unequivocal demonstration of gene transfer between two strains co-residing in the human gut, as the donor, recipient and transconjugant strains were isolated. The results suggest the dynamic adaptation by commensal bacteria in response to antibiotic treatment may occur readily.     

Spatiotemporal analysis,hotspot mapping,and clustering of confirmed cases of COVID-19 in the initial phase of the pandemic in Qom province,Iran

Objective: To identify the incidence rate, relative risk, hotspot regions and incidence trend of COVID-19 in Qom province, northwest part of Iran in the first s...     

A computer model for evaluating the osteotomy parameters of Chiari pelvic osteotomy

This study was conducted to evaluate the effect of the various osteotomy parameters on the biomechanical aspects of the hip joint on a computerised model. The data of the radiographs and a three-dimensional (3D) CT scan of six patients with coverage deficient hip joint were used to construct a 3D computer model. Then Chiari type osteotomies were simulated using various heights, angles and fibrocartilage thicknesses. A new angle called the mid acetabular center edge (MACE) angle was defined in a mid coronal CT cut. The optimum displacement for obtaining the maximum coverage averaged 73%. The angle and height of the osteotomy had a significant effect on the MACE angle (P value < 0.01). Our findings of these Chiari parameters may change the results of the osteotomy. The probability of adapting the proximal osteotomy segment to a deformed femoral head was explained by the model and a modified osteotomy “multiple height osteotomy” was proposed.     

Report on Patients with Non Transfusion-Dependent β-Thalassemia Major Being Treated with Hydroxyurea Attending the Thalassemia Research Center,Sari, Mazandaran Province,Islamic Republic of Iran in 2013

Hydroxyurea (HU) has been used to treat patients with non transfusion-dependent β-thalassemia major (β-TM) at the Thalassemia Research Center, Sari, Mazandaran Province, Islamic Republic of Iran since 1996. This study was performed to summarize and to share our experience. Medical records of all patients with β-thalassemia (β-thal) attending our center were reviewed in January 2013. Definition of β-TM was based on complete blood count (CBC), hemoglobin (Hb) electrophoresis, and for some patients, by the amplification refractory mutation system-restriction fragment length polymorphism (ARMS-RFLP) method. Patients who had not been transfused before, or had only occasionally had blood transfusions, were selected. Age at first blood transfusion, initial HU therapy and time of study was extracted from the records. The lowest Hb level before using HU and the last Hb value when on the HU regimen as well as the difference, were reported. Number of saved packed red cells was calculated according to duration of HU use and the usual needs of the patients. Hydroxyurea was discontinued before a planned pregnancy and during gestation and lactation periods. Hydroxyurea was discontinued for male patients willing to reproduce. A p value of <0.05 was considered statistically significant. It was consistent with 1856 patients/year, and 3542 units of blood were saved. We found HU to be effective and safe in treating patients with non transfusion-dependent β-TM. We strongly recommend HU therapy.     

Role of nitric oxide in the rat hippocampal CA1 area on morphine-induced conditioned place preference

Effects of intrahippocampal CA1 injections of L-arginine, a nitric oxide (NO) precursor, and N(G)-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, on morphine-induced conditioned place preference in male Wistar rats were investigated. Animals received subcutaneous (s.c.) injections of saline (1.0 ml/kg) or morphine (0.5-7.5 mg/kg) once daily for 3 days to induce conditioned place preference. The administration of L-arginine (0.3, 1.0, and 3.0 microg/rat), but not L-NAME (0.3, 1.0, and 3.0, microg/rat), prior to administration of morphine (5.0 mg/kg) during acquisition of morphine-induced conditioned place preference increased morphine-induced conditioned place preference, but the interaction between the response to morphine and/or L-arginine was not statistically significant. The response to L-arginine was blocked by L-NAME pre-administration. L-Arginine or L-NAME by itself did not induce conditioned place preference. The administration of L-arginine but not L-NAME, 1 min before conditioned place preference testing, increased the expression of morphine-induced conditioned place preference. Pre-administration of L-NAME blocked the L-arginine response. It is concluded that NO in the rat hippocampal CA1 area may be involved in morphine-induced conditioned place preference.