الفهرس 
List of TablesOnly 14 pages are availabe for public view
 |  | from | 216 |  |  |
| | | from | 216 | | |
Abstract
Conclusion and Recommendations
This study has illustrated that biofilm formation is an important cause of antibiotic resistance in P. aeruginosa strains isolated from patients with different types of infections in different departments at Sohag university hospital. 58% of these strains were found to be biofilm producers by tissue culture plate method and this character was reduced by exposure of these strains to garlic extract as QSI agent. Thus quorum sensing is an ideal target for prevention of biofilm formation and increased sensitivity to antibiotics.
Rrecommendations to decrease nosocomial Pseudomonas aeruginosa infections and decrease antibiotic resistant strains :
1- Strict implementation of infection control measures particularly hand hygiene practice and reliable cleaning techniques to decrease spread of nosocomial infection.
2- Proper cleaning, disinfection and sterilization of equipments and hospital environment to prevent cross transmission.
3- Active surveillance measures to identify patients infected with Pseudomonas aeruginosa especially biofilm producer .
4- Regular surveillance for biofilm producer Pseudomonas aeruginosa Especially in high risk units e.g, ICU and isolation of infected patients to prevent further transmission.
5- Avoid the use of broad spectrum antibiotics as a treatment for Pseudomonas aeruginosa infection before doing antibiotic sensitivity to avoid treatment failure and development of resistance due to unnecessary use of this class of antibiotics.
6- Search for alternatives to antibiotics as quorum sensing inhibitors.
Summary
Nosocomial infections (NIs) caused by Pseudomona aeruginosa present a widespread problem in today’s healthcare environment with between 4% and 10% of hospitalized patients acquiring an infection annually. Also, NIs have a significant burden to patients, they affect the general health of patients, cause functional disability, emotional stress and may lead to conditions that reduce quality of life.
In addition, the widespread use of antibiotics has fostered the development of resistance in a variety of pathogenic bacteria. Unfortunately, the emergence of bacterial strains that exhibit resistance to a variety of antibiotics (multi-drug resistant strains) are becoming the major causes of treatment failure of infections worldwide.
The opportunistic human pathogen Pseudomonas aeruginosa regulates production of numerous virulence factors via the action of two separate but coordinated quorum sensing systems, las and rhl. These systems control the transcription of genes in response to population density through the intercellular signals N-(3- oxododecanoyl)-L-homoserine lactone (3-oxo-C12-HSL) and N-(butanoyl)-Lhomoserine lactone (C4-HSL) leading to biofilm formation and increased resistance to antibiotics .
It is very important to use quorum sensing as an ideal target for controlling infections. There is a need to search for herbal products that are able to block quorum sensing and inhibit the expression of virulence determinants of P. aeruginosa leading to attenuation of its virulence without the side effects of synthetic compounds. There has been renewed interest in the development of newer compounds from medicinal plants with the aim of treating various diseases with negligible side-effects such as dimethyl sulfoxide (DMSO) , garlic extract , vanilla extract , and p-coumaric acid .
Our study was carried out in Sohag university hospital in the period between April 2016 and April 2017. 283 samples were collected from different hospital wards to detect Pseudomonas aureginosa strains isolated from patients with different types of infections .
Samples were taken from infected patients from different wards , cultured on selective media (cetrimide agar). 100 Pseudomonas aeruginosa were isolated all were subjected to antibiotic sensitivity testing(disc diffusion method). According to CLSI 2016 the antibiotics used are:
Meropenem,Pipracillin,Pipracillin/tazobactam,Ticarcillin/clavulanate,Aztreonam,Meropenem,Imipenem,Cefepime,Ceftazidime,PolymixinB,Colistin,Gentamicin,Tobramycin,Amikacin,Ciprofloxacin , Norfloxacin,Oflxacin and Gatifloxacin.
Pseudomonas aeruginosa strains were tested for detection of biofilm formation by congo red agar method , tissue culture plate method and PCR for detection of quorum sensing genes. 80% of strains were biofilm producers and 20% were non biofilm producers .
On exposure of biofilm producing strains to the sub-inhibitory concentration on aqueous garlic extract there was significant improvement of the antibiotic susceptibility profile and significant reduction of biofilm formation by congo red agar method and tissue culture plate method without deletion of quorum sensing genes indicatiog point mutations of these genes.