Effect of cyclophosphamide on the course of candida albicans infection in normal and vaccimated mice

To evaluate the immunomodulating effect of cyclophosphamide [Cy] on the course of Candida albicans [C. albicans]. We performed this study in the Shiraz Medical School, Shiraz, Iran during April to November 2003. Five groups of 10 mice [vaccinated group] were immunized by 5 equal injections of 2x105, 2.5x105 and 3x105 of the organism intraperitoneally. Then, the group received Cy on day zero and was challenged with lethal doses of C. albicans [7.74x105 colony forming unit] on days zero, one, 3, 6 and 12 post-Cy injection. Another 5 equal groups of 10 mice [non-vaccinated group] received Cy on day zero and similar to vaccinated ones were challenged with lethal doses of the organism too. The control groups received just Cy on day zero and were sacrificed on days zero, one, 3, 6 and 12 days post-Cy injection. We performed the hemogram and the spleen and studied the renal tissues microscopically and macroscopically. In vaccinated group, we observed an increase in survival time and in spleen and renal weights were visible while in non-vaccinated ones, a significant decrease was also observed on days one and 3 and an increased on days 6 and 12 post-Cy injection. We observed atrophy and necrosis in the spleen while inflammation and necrosis were also observed in the kidneys on days one and 3. We noticed a significant hyperplasia in the white pulp on days 6 and 12 post-Cy injection. We conclude that hyperplasia in the white pulp of spleen and the increase in peripheral polymorphonuclears due to selective effects of Cy could effectively protect the animal against C. albicans infection

Discrimination of dominant helicobacter pylori strains isolated from patients with different gastroduodenal pathologies by protein profiling

It is not clear what factors determine divergent outcomes of infections caused by H. pylori. In the present study, the protein profiles of different strains of H. pylori, isolated from three groups of patients with ulcerative disease, non-ulcerative gastritis and cancer disease, were analyzed using 1D-SDS-PAGE. The patterns of different H. pylori strains were highly divergent. About 30.76% [7 bands] of the 26 observed protein bands were common in all strains isolated from 3 groups of the patients. While the similarity for the strains inside each group were 75% [15 from 20], 76.47% [13 from 17] and 78.57% [11 from 14] for cancerous, ulcerative and nonulcerative group, respectively. Some of the observed bands were significantly specific for each group. Therefore, we speculated that some H. pylori strains might be more associated with a specific disease than others, giving the clustering of some, but not all, strains within each disease group. In conclusion, this study showed that protein profile can be a characteristic in discrimination of dominant strains in different gastric clinical status. Specific and dominant proteins of different strains isolated from three groups of patients under study were candidates for further exploration for laboratory tests, which analyze disease-specific H. pylori strains, and for diagnosis of the different diseases and outcomes associated with this widespread bacterium

Development of a sensitive quantitative competitive PCR assay for detection of human cytomegalovirus DNA

Accurate and rapid diagnosis of human cytomegalovirus [HCMV] disease in immunocompromised patients has remained as a challenge. Quantitative competitive PCR [QC-PCR] methods for detection of HCMV in these individuals have improved the positive and negative predictive values of PCR for diagnosis of HCMV disease. In this study we used QC-PCR assay, using a co-amplified DNA standard, to quantitate the HCMV glycoprotein B [gB] gene in different samples. A DNA internal standard [IS] was designed by replacing HCMV primer binding site at 5' ends of primers that amplifies a 156-bp fragment of lambda genome, and a 200 bp amplicon was produced. Two DNA fragments of 257 bp wild type and 200-bp [IS] were co-amplified with the same oligonucleotide primer sets, analyzed by gel electrophoresis and used for construction of a standard curve. From this, the copy number of the gB gene present in different samples could be determined. Co-amplification with 1,000 copies of IS, allowed quantitation of 10-100,000 of HCMV DNA in a single PCR. This rapid assay avoids using radioactive components and other less efficient quantitative systems. It has the potential for early identification of patients at high risk of development of HCMV disease, and is useful for therapeutic monitoring

Distribution patterns of methicillin resistance genes [mecA] in staphylococcus arureus isolated from clinical specimens

There is a growing concern about the application of molecular methods in epidemiological studies of infectious diseases. The objective of this study was to determine the genetic stability of methicillin resistance genes in Staphylococcus aureus for the evaluation of resistance strain distribution. One hundred and fifteen S. aureus isolates from patients with staphylococcal infection were collected. The isolates were screened for methicillin resistance by minimum inhibitory concentration [MIC] examination. The stability of methcillin resistance genes was examined by physical curing and PCR screening methods. The results showed that methicillin resistance Staphylococcus aureus [MRSA] had risen up to 43% in Nemazi Hospital [Shiraz, Iran]. Indeed, the incidence of MRSA in our hospital was 10% during the last four years. The ability to lose [curability] of methicillin resistance genes [mecA] was examined by physical curing method in 49 isolates with MIC >/= 16 micro g ml -1. No sign of curability of mecA gene was observed where 500 colonies from each strain have been studied and exhibited by the same MIC values before and after curing test. Positive PCR results for isolates with MIC >/= 16 micro g ml -1 before and after curing experiment have been achieved. These data confirm the results of curing method, indicating that stable genetic determinants confer methicillin resistance. These results support the hypothesis that resistance isolates may be selected due to clonal selection under antibiotic pressure used in clinics rather than transmission of mobile genetic determinant. The high prevalence of MRSA immerged in our Hospital could be originated due to antibiotic pressure and poor control measures