دراسة مقارنه بين بكتريا المكورات العنقودية الذهبية المقاومة لمضاد المثيسلين والحساسة لهذا المضاد واختبار الفعالية التثبيطية لبعض المستخلصات النباتية عليها == Comparative study between Methicillin resistant Staphylococcus aureus (MRSA) and Methicillin sensitive Staphylococcus aureus (MSSA), and detect the antimicrobial effects of some plant extracts on them
Author name:
هبة علي هلال الجبوري
Supervisor name:
مي طالب فليح
General topic:
Biology
Specific topic:
Microbiology - Bacteria
Degree:
Master
University:
University of Baghdad
Language:
English
University location:
Baghdad
First pages:
24T3163 - p.pdf
Abstract:
This study included collection of 75 clinical different samples from teaching laboratories of Medical city in Baghdad during the period from September 2009 - February 2010, these samples differed in their sources which included 30 nasal swabs,27 inflammatory wounds swabs, 6 sputum cultures, 5 ear swabs, 4 urine cultures, and 3 skin abscesses. The results of microscopic examination, biochemical tests and API staph strip results Confirmed that 44 of this isolates were belong to the genus Staphylococcus aureus distributed in 19 isolates from nasal swabs, 10 isolates from inflammated wounds swabs, 5 isolates from both ear swabs and sputum culture, and 3 isolates from urine culture and finally 2 isolates from skin abscesses culture. Antibiotic sensitivity test showed that 90.90% of isolates were Methicillin Resistant S. aureus (MRSA), while only 6.81% of these isolates were Methicillin Sensitive S. aureus (MSSA). At the same time, the isolates showed different types of resistance towards 11 different kinds of antibiotics ,where as 100% of the isolates were resistant to PenicillinG, 65.90% of isolates were resistant to Amoxicillin, and 54.54% of isolates were resistant to Co amoxiclave, in contrast the isolates revealed different low levels of resistance against Erythromycin 34.09%, Tetracycline 31.81%, Cephalexin 25%, Gentamycin 20.45%, and 13.63% for both Ciprofloxacin and Refampine, vancomycin and clindamycin 2.27% and 0.0% respectively. The virulence factors were detected for 44 isolates, results showed the ability of both multidrug resistant (MRSA) isolates and multidrug sensitive (MSSA) isolates to produce most extracellular enzymes except for Urease enzyme, the MRSA isolates were Urease producers , while the MSSA isolates unable to produce this enzyme. MSSA isolate(S7) and MRSA isolate(S33) were chosen to detect the ability of them to produce toxic shock toxin (TSS - 1) and Exfoliative toxin (scalded skin toxin), results of these tests showed incapability of both (MRSA& MSSA) isolates to produces any of these toxins. To determine the pathoginicity of the (S33) MRSA isolate, LD50 value was detected by using BALB/c mice known in Weight and age, the LD50 value was 3.9 106. The LD50 for MSSA (S7) isolate was not detected because this isolate doesn't show any lethal activity even in (1011) concentration. To compare between the pathoginicity of (S33) MRSA& (S7) MSSA isolates, histopathological studies were performed by injecting the BALB/c mice with 106 CFU/ml for (S33) MRSA isolate and 108 for (S7) MSSA isolate concentrations of bacterial cells, four days post inoculation mice were killed. Histological sections were prepared. Results of histopathological studies showed an observable activity and virulently of multidrug resistant isolate (S33) over than the activity and virulently of multidrug sensitive isolate (S7).especially in kidney, liver and spleen, while the results were adjacent for lungs, in contrast stomach and heart appeared no effect for both (S7) MSSA& (S33) MRSA isolates. The values of MIC were determined to three of antibiotics used in this study which were Vancomycin, Ciprofloxacin and Clindamycin, this test performed on (S7) MSSA& (S33) MRSA isolates. The results showed that the values of these three antibiotics were 1, 2, 0.250mg/ml for (S7) MSSA and 8, 4, 1 mg/ml for (S33) MRSA respectively. This study also included testing the activity of the crude juice of garlic, crude extract of pomegranate and crude oil of Eucalyptus against both multidrug sensitive MSSA (S7) and multidrug resistant MRSA (S33) isolates, garlic crude extract showed highest levels of effect against both S7& S33 isolates in two methods : well diffusion and pouring plates methods. In well diffusion method 10% concentration of crude juice appeared the highest growth inhibition effect, while in pouring plates method the concentration 10000 p.p.m appeared bactericidal effect. Also pomegranate crude extract and Eucalyptus crude oil appeared visible and strong effect against both S7&S33 isolates in both well diffusion and pouring plate method. Combination between antibiotics and garlic crude juice was performed. The MIC values of the three antibiotics after combination showed observable decreases. After combination the MIC values of Vancomycin decreased from 1mg/ml for S7 (MSSA) isolate & 8 mg/ml for (S33) MRSA isolate to 0.250 mg/ml to both two isolates, while the MIC values for ciprofloxacin decreased from 2 mg/ml for (S7) MSSA isolate & 4 mg/ml for (S33) MRSA isolate to 0.125 mg/ml, for Clindamycin the values of MIC decreased from 1mg/ml for S33 (MRSA) isolate &0.250 mg/ml for S7 (MSSA) isolate to 0.125 mg/ml. these results means that the combination between garlic juice and antibiotics give synergistic effect against S. aureus especially the multiresistant isolate.
