Carbapenems are among the best choices for treatment of infectionscaused by multidrug resistant Gram-negative rods
.
In recent years, Egypthas been considered among the countries that reported high rates of antimicrobial resistance
(Zafer et al., 2014)
.The occurrence of a Mβ-positive isolate in a hospital settingrepresents a therapeutic problem, as !ell as a serious concern for infection control management. The accurate identification and reportingof Mβ-producing
P. aeruginosa
!ill aid infection control practitioners in preventing the spread of these multidrug-resistant isolates
(Arunagiri et al., 2012)
.This study aimed to evaluate IM"- E#T$ C#T and IM"- E#T$##%T as phenotypic screening methods for Mβ detection in isolatedstrains of
P.aeruginosa
, detection of Mβ genes in those isolates andformulation of antibiotic policy for treatment of infections by Mβ producing
P.aeruginosa
.In this study a total number of &&' different samples !ere collectedfrom patients from (enha )niversity *ospital and (enha Teaching*ospital and +''
P.aeruginosa
strains ./0 !ere recovered fromthem.The isolated
P. aeruginosa
strains !ere sub1ected to2 +0$ntibiotic susceptibility by disc diffusion test.&0Mβ detection by both2a0 "henotypic method2 by both IM"- E#T$ C#T and IM"-E#T$ ##%T. b0 Genotypic method2 by multiple3 "C4
)131(


6-Summary and Conclusion
The present study revealed that2 5ut of +''
P.aeruginosa
isolates, & strains &/0 !ere imipenemresistant and + strains of them 6'/0 !ere carrying genes responsiblefor Mβ production +/ of the total number of
P.aeruginosa
0. Thirteenstrains +7/0 !ere carrying
VIM
gene !hile t!o strains &/0 !erecarrying both
VIM
and
SPM
genes together.
IMP, GIM-1, SIM-1
genes!ere not detected. 8one of the imipenem sensitive strains !ere carryinggenes of Mβ production.IM"- E#T$ C#T !as found to be more sensitive 97.7/0 than IM"-E#T$ ##%T 66.:/0. The specificity of both tests !as +''/ in relationto the gold standard "C4. 8early all
P.aeruginosa
strains !ere resistant to cefota3im,cefotria3one, cefopera;one, cefta;idime, cefepime and amo3icillinclavulanic acid !hile all strains !ere sensitive to colistin and polymy3in(. 8early all Mβ producers !ere resistant to most antibiotics used!hile +''/ of them !ere fully sensitive to colistin and polymy3in (.There !as insignificant relation bet!een Mβ production and each of patient age, patient se3 and site of infection.There !as significant decrease in the number of Mβ positive cases inshort periods of hospitali;ation. β-lactam antibiotic inta