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التحري عن جين الاوتولايسين في المكورات العنقوديه البشروية المقاومة لمضاد الفانكومايسين == Autolysin Gene Detection In Vancomycin Resistant Staphylococcus Epidermidis
Author name:
مريم خميس عبد ربة بريس
Supervisor name:
مي طالب فليح
General topic:
Biology
Specific topic:
Microbiology
Degree:
Master
University:
University of Baghdad
Language:
English
University location:
Baghdad
First pages:
24T2683 - p.pdf
Abstract:
من مجموع مئة عينة سريرية جمعت من مصادر مختلفة شملت الحروق والدم والجروح ومسحات انفية, تمكنت 90 عزلة من النمو على اكار المانيتول الملحي , ومن بينهم 40(44.4 %) عزلة عائدة لبكتريا المكورات العنقودية المنتجة للانزيم المخثر للبلازما و50 (55.5%) عائدة لبكتريا ا | Out of one hundred clinical samples were taken from different sources which include burns, blood cultures, wounds and nasal swabs infections ; 90 isolates developed growth on mannitol salt agar. Among these, 40 (44.4%) were Coagulase positive (Staphylococcus aureus) isolates, 50 (55.5%) belong to coagulase negative staphylococci in which Staphylococcus epidermidis isolates were 30(60%). The pattern of antibiotic susceptibility of Staphylococcus epidermidis isolates to 12 antibotics (Amoxiclav, Ceftazidim, ciprofloxacin, clindamycin, Erythromycin, Gentamycin, Imipenime, Penicillin G, Tetracycline, Rifampin , Methicillin, and Vancomycin) were determined using disc diffusion method. The results revealed that resistance to Penicillin G10 and Amoxiclav (Amoxicillin - clavulanic acid) were 100%, Methicillin were 93%, Erythromycin were 90%, Gentamycin and Clindamycin were 70%, Tetracycline and ceftazidim were 75%, Ciproflaxacin were 60%, Rifampin were30%. 95% of S.epidermidis isolates were sensitive to Imipenim and 5% of them were intermediate resistant, while these isolates showed 90% sensitivity to vancomycin. 19 isolates were multidrug resistance. Minimum inhibitory concentration of S.epidermidis isolates to vancomycin, was determined. The results revealed that (12) S.epidermidis isolates (40 %) were vancomycin resistant, the MIC of them were between 256 ?g\ml and 32 ?g\ml, (4) S.epidermidis isolates (13.3%) were intermediate resistance, the MIC to 3 of them were 16 ?g\ml and the last was 8 ?g\ml. Some virulence factors of VRSE and VSSE were detected including the hemolysin, protease, lipase and urease. The S. epidermidis isolates were produce hemolysin, protases, lipase and urease, were 100%, 100%, 25%, 100% respectively in VRSE, while in VSSE 100%, 100%, 60%, 100% respectively. The isolates were subjected to polymerase chain reaction (PCR) technique in monoplex pattern to amplify resistant incoding gene : the vanA, vanB and autolysine gene aae gene. The results by this study showed that 12 (40%) S. epidermidis isolates gave the implicone size (1030 base pair) of the vanA gene. However the results of MIC and PCR were similar but no any isolates gave product for presence of vanB gene. All S.epidermidis were able to produce implicone size(858bp) of aae gene. The effect of vancomycin resistant S. epidermidis on cell autolysis activity was detected by whole cell autolytic assay.The results revealed that there was significant difference among three isolates, the VSSE isolate (S.epidermidis 22) have the highest autolytic activity in the presence of antibiotic, followed by the VRSE isolate (S. epidermidis 1) and the VISE isolate (S. epidermidis14) which was the lowest autolytic activity with the presence of antibiotic. The result of transmission electron microscope (TEM) showed that the VRSE isolates (S.epidermidis 1) have thicker cell wall followed by VISE (S.epidermidis 14) isolates.However, the VSSE (S.epidermidis 22) didn't showed any cell wall thickening.
