Combined use of polymerase chain reaction, interferon- gamma and soluble IL-2 receptor for differential diagnosis of tuberculous pleural effusion

Background and Objectives: Rapid and early differential diagnosis between tuberculous and nontuberculous pleural effusion [TPE and NTPE] is a critically important clinical problem. The paucibacillary nature of TPE and inefficiency of conventional biochemical and microbiological investigations challenge the application of more comprehensive markers. In this study we evaluated the relevance of applying polymerase chain reaction [PCR], for detection of Mycobacteria Tuberculosis- DNA [TB-DNA], in association with interferon gamma [IFN-gamma] and soluble IL-2 receptor [sIL-2R] levels in pleural fluid for differential diagnosis of TPE

Patients and Methods: Study population included 60 patients with pleural effusion [PE]; 40 patients with TPE [7 patients with confirmed tuberculosis [TB] and 33 patients with probable TB], and 20 patients with non-tubrculous, non-infectious pleural effusion [NTPE] [10 cases due to malignancy and 10 cases due to heart failure]. PE samples were assessed for: biochemical markers [total protein and glucose], lymphocytic count, presence of acid fast bacilli in Ziehl-Neelsen [Z.N.] stained direct smears and by culture on Lowenstein Jensen [L.J.] medium], TB-DNA using conventional PCR, as well as levels of IFN-gamma and sIL-2R using commercial ELISA kits

Results: Biochemical markers, in particular total protein level, confirmed the exudative nature of TPE and malignant PE. The percentage of lymphocytes in PE was significantly higher in patients with confirmed TB [>80%] than all patients in other studied groups. All patients with confirmed TB were positive for TB-DNA PCR and had IFN-gamma and sIL-2R levels more than calculated cut off points. However, probable TB group showed a wide range of variability. None of patients with malignant PE but three of heart failure patients were positive for TB-DNA PCR. All patients with NTPE had IFN-gamma level less than cut off point. On the other hand, all patients with heart failure but 50% of patients with malignancy had sIL-2R level less than cut off point

Conclusion: Clinical data together with simultaneous detection of TB-DNA by PCR and measurement of IFN-gamma and sIL-2R levels as well as lymphocytosis [>80 %] in PE could provide the basis for rapid and efficient diagnosis of pleural TB in different clinical settings

Characterization of uropathogenic escherichia coli strains isolated from community acquired and hospital acquired infections in Alexandria

Uropathogenic strains of Escherichia coli [UPEC] cause the vast majority of urinary tract infections [UTI] in both community and hospital settings. They exhibit a variety of virulence properties that determine the severity of infection. The aim of this study was to determine the prevalence of two urovirulent genes [papC and cnf1] and production of haemolysin among UPEC strains causing community acquired [CA] and hospital acquired [HA] UTI, to test the susceptibility of these strains to different antimicrobial agents and to screen for extended spectrum beta-lactamase [ESBL] production. One hundred UPEC strains were collected during the period from June 2005 to May 2006 from cases of CA [50 strains] and HA [50 strains] UTI. Of them, 40 strains were isolated from upper UTI cases, and 60 strains were isolated from lower UTI cases. PapC and cnf1 genes were detected by real-time TaqMan PCR assay. Haemolysin production was detected phenotypically. The double disk synergy method was used to screen ESBL production. Fifty strains [50%] possessed one or more of the studied virulence factors. They were significantly more frequent among isolates causing upper UTI [75%] than those causing lower UTI [33.33%, X[2] =6.404, p= 0.011], but, no significant difference was found between CA and HA strains. HA-UPEC strains showed significant higher resistance to third and fourth generation cephalosporins, quinolones, and nitrofurantoin. No resistance to carbapenems was detected among our strains. Quinolone resistance was detected in 52% of the strains, with significant prevalence among lower UTI and HA strains. Forty two strains [42%] were multidrug resistant [MDR], with more significant prevalence among HA strains. Both quinolone resistant and MDR isolates exhibited significantly lower virulence score than did the susceptible isolates. Twenty eight strains [28%] were found to be ESBL producers, 79% of them [22/28] were quinolone resistant with no significant differences regarding their source. None of the ESBL producers possessed any of the studied virulence genes. Overall, the results showed that virulence factors were more prevalent among isolates causing upper UTI. Quinolone resistance itself may be a virulence factor in lower UTI with an observed association between it and ESBL production. Further studies are needed to clarify these relations

Biochemical view on the effect of hepatitis delta virus infection on expression of hepatitis B virus in blood donors

One thousand voluntary blood donors attending the Blood Bank of Medical Research Institute, Alexandria University were enrolled in the present study. Sera from blood samples were separetd for screening of HBsAg using ELISA technique. Screening of 200 1-IBsAg negative blood samples for past exposure to HBV infection was also performed through the detection of anti-HBc using specific ELISA kit. Determination of ALT and AST revealed a significant increase among HBsAg positive group while, Malondialdehyde [MDA] detection revealed the absence of the causative relationship between MDA and liver injury. On the other hand, no anti-HDV could be found among the HBsAg-ve/anti-HBc+ve group of blood donors [46 cases]. PCR analysis for HBV-DNA was performed in the chosen 24 serum samples. None of them was positive for HBV-DNA regardless their positively or negativity to the different serologic markers studied

Lysozyme production: a possible index of pathogenicity among staphylococci

Lysozyme production was tested among 63 coagulase positive staphylococcal strains [20 of pathogenic origin and 42 from healthy nasal carriers] and 26 coagulase negative staphylococci isolated from cases of urinary tract infections. It was found that this property was significantly higher among pathogenic staphylococci [61.9%] than nasal staphylococci [38%]. Regarding coagulase negative staphylococci this property was much less frequent [3.8%]. Other criteria of pathogenicity [hemolysis, DNase production and growth on Mannitol salt agar] were tested. These four criteria were more frequent among pathogenic staphylococci than those isolated from healthy nasal carriers. DNase production was the most frequent property in association with lysozyme production and these two properties could be used as a good index of pathogenicity among coagulase positive staphylococci