RÉSUMÉ
Considering the increasing incidence of infection due to methicillin resistant [MR] staphylococci; reliable, accurate and rapid testing for MR is essential for both antibiotic therapy and infection control regimens. Our mmain objective was to evaluate the accuracy of cefoxitin and moxalactam disk diffusion [DD] tests and that of Mannitol Salt agar [MSA] screening test using cefoxitin and oxacillin for detection of MR among S.aureus and coagulase negative staphylococci [CoNS] using PCR for mecA gene as "gold standard" comparison assay. Commercial MRSA-screen latex agglutination test [LAT] was performed to detect mecA gene product [PBP2a]. The following susceptibility tests were studied: E test for oxacillin minimal inhibitory concentration [MIC], DD test using oxacillin [1[micro]g], cefoxitin [30[micro]g] and moxalactam [30[micro]g] disks on Muller Hinton agar plates and agar screening test using MSA containing oxacillin [MSA-Ox] [1[micro]g, 4[micro]g and 6[micro]g/ml] and MSA containing cefoxitin [MSA-Cefox] [4[micro]g/ml]. Methicillin resistance was detected in 74% of 77 staphylococcal clinical isolates [68.8% in 48 S.aureus and 82.7% in 29 CoNS]. Compared to PCR assay, LAT showed 100% sensitivity and specificity for both S.aureus and CoNS isolates. Among S.aureus isolates, diagnosis of MR was best achieved by E-test, moxalactam DD and MSA-Cefox [all had sensitivity and specificity of 100% and 86.7% respectively] while among CoNS isolates, diagnosis of MR was better performed by E-test and MSA-Cefox [both had 100% sensitivity and specificity]. We conclude that E-test could be an accurate method in detection of MR. In laboratories that depend mainly on disk diffusion test, a combination of cefoxitin and moxalactam disks should be used to increase the accuracy of the test. MSA-Cefox [4[micro]g/ml] is a promising screening medium with high accuracy. Identification of MR by applying the MRSA screen LAT is a reliable alternative for clinical laboratories where molecular biology techniques are not readily available
RÉSUMÉ
This study aimed to evaluate the potential of determining bone density using digital radiography in the detection of the bone changes of renal osteodystrophy as compared to biochemical findings [serum calcium, phosphorous and alkaline phosphatase]. This study included twenty five children with CRF aged 6 to 12 years of variable etiology; 14 of them were on dialysis and compared with 10 age and sex matched healthy controls. They were examined using digital radiography together with blood samples to measure serum calcium, phosphorous and alkaline phosphatase. 3 aluminium step wedges were attached to the film cassette to give a reference image on the radiograph. Panoramic radiographs were digitalized, stored and processed by a computer. A geometrically standardized rectangular area of interest was measured for each radiograph. Bone density using digital radiography adequately demonstrated bone status by determining bone density more conspicuously than do the biochemical findings. There were no significant differences detected between dialyzed and non-dialyzed patients so they were poured as one group. While, there was significant decrease in serum calcium and significant increase in serum phosphorous and alkaline phosphatase in patients group compared to controls group. Also, reduction of bone mineral density was detected in patients group compared to controls group and positive correlation was found between bone density of the whole sample and their serum calcium levels. No meaningful correlation could be established between bone mineral density and duration of dialysis. The study concluded that bone density using digital radiography is a potentially useful tool for evaluating the hone density and consequently the bone status of renal osteodystrophy