ABSTRACT
Coagulase-negative staphylococci [CNS] are one of the major causes of nosocomial infections. Methicillin [oxacillin] resistant strains are particularly important because they narrow therapeutic options. Detecting methicillin resistance among CNS has been a challenge for years. The objective of this study was to evaluate the ability and accuracy of four phenotypic methods, disk diffusion [DD]; agar screening plate with 6 micro g of oxacillin per ml [OXA]; E-test and the MRSA-Screen latex agglutination test [Denka-Seiken, Tokyo, Japan], to determine the susceptibility of CNS to oxacillin. The methods were evaluated by using the presence of the mecA gene, as detected by PCR, as the "gold standard". One hundred and ninety seven strains of CNS of 7 species were analysed. 49.2% were mecA positive. For the different methods evaluated, the sensitivities and specificities were as follows: for disk diffusion, 93.8 and 93%, respectively; for the agar screen test 95.9 and 98%, respectively; for E-test, 100 and 95%, respectively; and for the slide latex agglutination test, 96.9 and 100%, respectively. The latex agglutination test sensitivity was increased to 100% when retested after induction. In conclusion, all of the phenotypic methods evaluated in the present study appeared to perform very well for the detection of oxacillin resistance in CNS. The MRSA-Screen latex agglutination test was not only the most sensitive, specific and accurate method but also rapid and technically simple method to be applied in routine laboratories for the detection of oxacillin resistance which is mediated by the mecA gene
ABSTRACT
Neonatal septicemia represents a major clinical problem in neonatology with high morbidity and mortality rates despite the progress in neonatal intensive care and antibiotics. Clinical diagnosis of septicemia in newborn infants is not easy and there is no laboratory test with 100% specificity and sensitivity with the exception of blood culture, the results of which are not available for at least 48-72 hours. The purpose of this study was to compare the utility of a 16S rRNA PCR assay to that of the conventional blood culture for detecting bacteria in blood obtained from neonates suspected of having septicemia. The present work included 50 neonates with provisional diagnosis of neonatal septicemia and 25 non infected neonates as control group. For each neonate the following was done: Full history taking, full clinical diagnosis, routine investigations including complete blood cell count and C-reactive protein [CRP], conventional blood culture for isolation of the causative organism and its identification and lastly the polymerase chain reaction for detection of the 16S rRNA gene from blood of septicemic neonates. The results of this study showed that: Only thirty nine neonates [78%] of those diagnosed as having or suspected to have septicemia on clinical backgrounds had given positive blood culture results. The most common isolated organisms were Klebsiella pneumonia [41.02%], coagulase negative staphylococci [CoNS] [20.51%], E. coli [10.26%] and S. aureus [10.26%]. K. pneumonia was the commonest isolated organism in early onset infection while CoNS was the commonest in late onset infection. Thirty eight of cases with positive blood culture [97.44%], two cases with negative blood culture [18.18%] and one of the control group [4%] were positive by 16S rRNA PCR. The sensitivity, specificity, positive and negative predictive values for 16S rRNA PCR in relation to blood culture were 97.4, 91.7, 92.7 and 97.1%, respectively and the accuracy was 94.7%. These values were superior to that of CRP [89.7, 83.3, 85.4 and 88.2%, respectively with accuracy of 86.7%]. Our results suggested that 16S rRNA PCR is a rapid, sensitive and specific diagnostic test for ruling out neonatal septicemia
ABSTRACT
It has been recently hypothesized that Hepatitis C virus [HCV] and Helicobacter pylori [H.pylori] might be involved in the pathogenesis of non-Hodgkin's lymphoma [NHL]. However, most of the studies were done on adult patients. So the objective of this study was to determine the prevalence of these infections in pediatric NHL patients and if there is any possible clinical or histopathologic picture linked to the presence of these infectious agents. The study was carried out on 40 pediatric NHL patients, either as new cases or with relapsing disease, presenting to the Hematology Unit of Pediatric Department. In addition, 20 apparently healthy children were studied as control group. Each child was investigated for the presence of H.pylori and HCV IgG antibodies using enzyme immuno-assay [EIA] and for the presence of HCV-RNA by the reverse transcriptase polymerase chain reaction [RT-PCR]. H.pylori IgG antibodies were detected in 19/40 of pediatric NHL patients [47.5%] and in none of the control group [P < 0.001]; whereas HCV antibodies were found in 8/40 of the patient group [20%] and in 1/20 of controls [5%] [P > 0.05]. HCV-RNA was detected by RT-PCR in 7/40 [17.5%] of the patients and in none of the controls. No specific histological subtype, extra-nodal presentation nor stage of disease was related to H.pylori or HCV positivity. Older age group was related to H.pylori positive NHL patients. Also a positive relation between the presence of H.pylori antibodies and the complaint of vomiting and diarrhea was observed in the patient group [P < 0.001]. In conclusion, a high prevalence of HCV and H. Pylori infections was reported in pediatric NHL patients. As regard the hypothesis of their pathogenetic role in lymphomagenesis it is still unclear, whether these agents have a direct role in malignant transformation in pediatric lymphoma since a typical NHL clinico-histological feature associated with HCV and H.pylori is deficient