Almost all species of Enterobacteriaceae
shows the resistance to antimicrobial drugs. Antimicrobial resistance of
enterobactericeae species are not only against the 3rd generation
cephalosporins drugs but is also resist aztreonam, cefotaxime, ceftazidime,
aminoglycosides, quinolones and cotrimoxazole.(Branger et. al., 2005)
Specieses that produce (ESBL) extended
spectrum beta lactamases have no exception in the resistance of antimicrobial
drugs mostly hospital acquired infections are due to ESBL producing specieses. (Gniadkowski
et. al., 2002)
Beta lactamases cause the hydrolysis of
beta lactam ring present in beta lactam drugs. Bacterial cell wall is build up
by peptidoglycan layer and penicillin binding proteins maintained it. Function
of protein binding protein is inhibited by beta lactamases. (Shukla et. al.,
2005)
Breakdown of beta lactam ring in beta
lactam drug change the chemical structure of beta lactam drug. By this change
drug is not able to recognize the enzyme ehich is responsible for the synthesis
of peptidoglycan layer of cell wall of bacteria. (Anwar et. al., 2007)
By two mechanisms enterobactericeae
resist the 3rdgeneratoncephalosporins. The first one is chromosomal
mediated and other one is plasmid mediated. Clavulanic acid inhibit the plasmid
mediated beta lactamases while it cannot able to inhibit chromosomal mediated
beta lactamases of enterobatcericeae .Extended spectrum beta lactamases are plasmid
mediated beta lactamases. Long time ago ESBL was reported but mostly clinicians
do not knows about its importance and also large number of microbiological
labortries do not know how to detect ESBL. (Mumtaz et. al., 2007)
Now it is very easy to detect and
identify ESBL producing species of enterobactericeae by the advancement in
microbiology field. Limited data is available of frequency of ESBL producing
enterobactericeae in Pakistan. (Chambers et. al., 2004)
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