ABSTRACT
Introduction: Hospital-acquired
pneumonia (HAP), particularly ventilatorassociated
pneumonia (VAP), causes
considerable morbidity and mortality
despite antimicrobial therapy and advances
in supportive care Pseudomonas(P)
aeruginosa is a leading cause of nosocomial
infections all over the world, especially of
HAP and VAP, The extended spectrum 13-
lactamase P aeruginosa producers (ESBLs)
have recently emerged as one of the most
worrisome resistance that have been rapidly
spreading through many countries The aim
of this study was to evaluate the mortality
of the subset of patients with HAP due to
P aeruginosa in a setting of beta-lactarnases
such as ESBL (Extended spectrum betalactamase
production . New media were
used in their isolation to be tested for
pseudomonas selectivity and enhancement
of different pigment that are produced by
Pseudomonas aeruginosa.
Methods: In this study, 76 samples were
collected from nasocomial pneumonia
cases. P. aeruginosa isolates were recovered.
Conventional microbiology methods were
used for P. aeruginosa identification,
isolation, antibiotic susceptibility testing
(using disk-diffusion methods) and fllactamase
production testing. P.aeruginosa
isolates were recovered and grown on
different types of media[basic,enriched and
selective media e.g P aeruginosa selective
agar (PASA), Kings A and 13]; to demarcate
its colonies, isolate pigments producers and
to isolate the extended spectrum P.
aeruginosa p-lactamase(ESBL) producers.
ESBL testing was done using disc diffusion
testing susceptibility and Epsilon(E) test. A
prospective observational study was
performed and it was constructed to identify
risk factors for 30-day mortality.
Results: All P aeruginosa isolates in this
study were grown (100%) on all media used.
Gram positive isolates were inhibited
(100%) on PASA, Kings A and Kings B.
While Gram negative isolates were
inhibited (100%) on PASA only and were
not inhibited on other used media. The
demarcation of? aeruginosa colonies were
detected in 100% on PASA, 22.58%on
-Kings A, 37.50% on Kings B, while nutrient
and blood agar media could not demarcate
colonies at all.
In this study, Kings B agar was the best
medium for isolation of pigmented
producers (68% fluorescein and 31.50%
rubrin), pigments detected on other media
with variable range: 67.50%) on PASA
(only fluorescein), 40.70 % on nutrient and |
