الفهرس 
TitleOnly 14 pages are availabe for public view
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Abstract
K.pneumoniae is a member of the Enterobacteriaceae family, Gram-negative, non-motile and encapsulated bacterium. K. pneumoniae causes a wide spectrum of nosocomial and community acquired infections of human, such as pneumonia, urinary tract infection, intra-abdominal infection, bloodstream infection, pyogenic liver abscess and meningitis. There are two major types of K.pneumoniae; hypervirulent and classical, the latter is less severe than hypervirulent.
Biofilm and siderophore are virulence factors that protect bacteria and makes them more resistant to antibiotics than planktonic bacteria, additionally they increase the bacteria’s ability to evade immune system. Biofilm formation genes include FimH, mrkD and ycfm and that for siderophore genes include Kfu, entB and iutA.
The aim of the present study was to detect some of the virulence genes that are responsible for biofilm formation and siderophore production which are implicated in the pathogenesis of K. pneumoniae isolated from different clinical specimens.
In the present study 50 bacterial isolates submitted to the Microbiology Department of Medical Research Institute, Alexandria University were confirmed as K.pneumoniae by culture on blood and MacConkey agar plates, microscopic examination and biochemical test. Antimicrobial susceptibility testing was done by Kirby-Bauer method. Biofilm formation was detected phenotypically by crystal violet method, hypermucoviscosity by string test and genotypic detection for virulence genes was done by conventional PCR. Antibiotic resistance categories varied among the isolates, MDR isolates were detected in 60% while Non-MDR were detected in 40% of K.pneumoniae isolates.
Phenotypically, biofilm formation was positive in 76% and negative in 24%. Genotypically, FimH and ycfm genes were detected in 100% of isolates while mrkD was detected in 98% of isolates.
Siderophore genes Kfu, entB and iutA were detected in 100%, 68% and 34% respectively among 50 isolates.
Finally, phenotypically by string test 66% of isolates were classified as hypermucoviscous, while 34% of isolates as classical. rmpA gene was detected in 52% of isolates.
Summary and Conclusions
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from this study we can conclude the following:-
Abuse and misuse of broad spectrum antibiotics are major contributing factors in the high resistance rate.
K.pneumoniae is highly resistant to a wide spectrum of antibiotics such as fourth generation cephalosporins, so possibly in near future there will not be any proper antibiotics for this bacterium.
Carbapenems, especially Meropenem are still active in more than 72% against K.pneumoniae. Genotypic detection was more sensitive than phenotypic detection for biofilm formation.
FimH, mrkD, ycfm genes are implicated in multisystemic infection of K.pneumoniae.
Enterobactin gene (entB) is more predominant than other siderophore genes (iutA, Kfu).
Kfu and iutA genes are involved in systemic infection of K.pneumoniae.