RESUMEN
Neonatal sepsis is a significant cause of morbidity and mortality in neonates. The gold standard for detecting bacterial sepsis is blood culture. However, it has low sensitivity and a reporting delay of approximately 48-72 h. Molecular assays for the detection of bacterial DNA represent possible new diagnostic tools for early identification of a bacterial cause. This study aimed at comparing a broad range 16S rDNA PCR to conventional blood culture for detecting bacterial DNA in blood samples from neonates with suspected sepsis. Fifty neonates with suspected sepsis, admitted at Neonatal Intensive Care Unit of Ain Shams University Hospitals, were included in this study. From each neonate, a minimum of 2-3 ml blood was collected by standard sterile procedures, 1 ml for conventional blood culture and 1-2 ml EDTA blood for PCR. The isolated microorganisms were identified by conventional microbiological methods. Thirty neonates [60%] gave positive blood culture results. The most frequently isolated microorganisms were Staphylococcus aureus [n = 17, 56.7%], followed by Coagulase negative Staphylococci [n = 7, 23.3%], Escherichia coli [n = 4, 13.3%], and Candida spp. [n = 2, 6.7%]. Twenty-eight [56%] neonates gave positive bacterial blood culture while 35 [70%] neonates gave positive PCR results. Considering the blood culture as the gold standard in diagnosis of bacterial neonatal sepsis, the sensitivity, specificity, positive predictive value and negative predictive value of PCR in detecting bacteremia relative to blood cultures were 20/28 [71.42%], 7/22 [31.81%], 20/35 [57.14%] and 7/15 [46.66%], respectively. In conclusion, PCR approach appears to be a relatively easy, reliable and valuable complementary method for diagnosis of neonatal sepsis for samples obtained during antimicrobial treatment especially when routine cultures remain negative. Staphylococci spp. has played an important role in causing neonatal sepsis. So, implementation of simple infection control measures such as hand washing, barrier nursing and promotion of clean deliveries should be considered to reduce neonatal sepsis
RESUMEN
Tuberculosis [TB] is a serious public health problem that especially prevalent in developing countries. An essential element in the control of TB is the rapid, sensitive and specific identification of the causative agent. Mycobacteriophages constitute a potentially useful approach for detecting viable Mycobacterium tuberculosis bacilli as well as for susceptibility studies. The aim of this study is to evaluate the diagnostic value of the Phage Tek MB kit for pulmonary tuberculosis in comparison with standard Lowenstein-Jensen [LJ] media and staining techniques for respiratory specimens. Sputum specimens submitted for diagnosis of mycobacterial disease at Ain Shams University hospital from August to November 2004 were included in the study. Specimens were studied using both of the conventional methods [direct microscopic examination and culture in LJ medium] and the Phage Tek MB assay. The sensitivity, specificity, positive and negative predictive value for the FAST Plaque TB assay relative to that of culture were 65.52, 100, 100 and 52.38%, respectively. The sensitivity was much higher in smear positive samples in comparison to smear negative ones [73.91% and 33.33%, respectively]. FAST Plaque TB proved to be specific, and rapid. It is able to detect M. tuberculosis in clinical samples within 1 day with 100% specificity, long before culture results]. Also it is cheap technology in comparison to PCR and would be suitable for use by routine microbiology laboratories, especially in developing countries