الفهرس 
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Abstract
Conclusion and Recommendations
In this study a high level of resistance of Staphylococcus aureus to multiple classes of antibiotics and upward trend in emergence of CAI with Staphylococcus aureus strains as well as in hospitals was observed. This has become a threat to public health. In order to prevent transmission of these community acquired strains, accurate and rapid monitoring techniques should be administered in both clinical and community settings with the wise use of antibiotics and avoid unnecessary treatment with broad spectrum antibiotics for Staphylococcus aureus without antibiotic sensitivity testing.
It’s important to reduce the spread of HAI by strict infection control measures as hand hygiene practice, proper sterilization of the equipment, cleaning hospital environment and regular surveillance for resistant strains of Staphylococcus aureus with isolation of infected patients to prevent transmission of infection.
It is important to control development of antibiotic resistance by monitoring potential developing of new aminoglycoside resistant genes that may be produced within S. aureus population. This will help to establish effective antibiotic therapies and prevent nosocomial infection as well as environmental spread of resistant strains.
PCR assays allow for the faster establishment of effective antibiotic therapies, and will lead to improved therapeutic success and reduced empirical treatments with broad-spectrum antibiotics, which are costly and have high toxicities, and eventually slow potential development of antibiotic resistant organisms. In terms of infection control programs, such rapid detection of resistance could be used to prevent nosocomial spread of MRSA in advance.
Using VITEK provides rapid and easy method for antibiotics sensitivity testing with high accuracy that helps to measure the MIC for many antibiotics at the same time so can be used to avoid the development of resistance that is caused by empirical treatments, however unfortunately it is expensive.
Summary
Staphylococcus aureus is one of the most important causative agents in both hospital and community acquired infections. This bacterium can cause various types of infection, including sepsis, pneumonia, wound sepsis, endocarditis, catheter-related infections, and urinary tract infections (UTIs).
Community acquired staphylococcal infection differs from nosocomial staphylococcal infection in that it does not generally belong to the major clonal groups of epidemic MRSA and is susceptible to most non-beta lactam antibiotics. In contrast, nosocomial MRSA is generally multidrug-resistant.
Because of the high distribution of MRSA, these bacteria are now resistant to certain other antibiotics, such as tetracyclines, aminoglycosides, and lincosamides. These drug-resistant strains have become more difficult to treat.
Aminoglycosides are one of the classes of antibiotics that play an important role in the treatment of staphylococcal infections. These are often used synergistically in combination with either beta-lactam or glycopeptides, especially for the treatment of complicated staphylococcal infections. However, today MRSA have acquired multiple resistances to a wide range of antibiotics including aminoglycosides.
The three mechanisms of resistance to aminoglycosides are changes in the position of the ribosomal binding site for the drug, reduced permeability of the drug, and drug inactivation by enzymes. The enzymatic inactivation by aminoglycoside modifying enzymes (AMEs) is an important mechanism of resistance in staphylococcal species.
Our study was carried out in Sohag university hospital in the period between December 2018 and December 2019. 150 samples were collected to detect Staphylococcus aureus strains isolated from patients with different types of infections.
Sixty two samples were positive for Staphylococcus aureus and were subjected to antibiotic sensitivity testing by E-test and by VIEK. Then the isolates were tested for AMEs genes by PCR.
It was found that the Staphylococcus isolates of HAIs were more resistant to antibiotics, including aminoglycosides, than Staphylococcal isolates of CAIs. Also, aac (6’)-Ie/aph (2”) gene was more commonly distributed than aph (3)-IIIa gene among the isolates.