الفهرس 
ACINETOBACTER SPECIESOnly 14 pages are availabe for public view
Abstract
A cinetobacter spp. have emerged as one of the most
important pathogens involved in health care associated
infections in recent decades, characterized by their ability to
accumulate different mechanisms of antimicrobial resistance,
often showing a multidrug-resistant phenotype.
Due to the high morbidity and mortality rates of severe
drug resistant Acinetobacter spp infections, combination
therapies, as opposed to monotherapy, are suggested. A
synergistic effect may be developed when antibiotics are used
in combination. Through this synergistic effect, treatment
efficacy can be improved and resistance can be prevented.
During this study, one hundred isolate of drug resistant
Acinetobacter species identified by routine culture and
sensitivity using disc diffusion susceptibility test were collected
from critically ill patients admitted to Ain Shams University
Internal medicine intensive care units. The isolates were
subjected to: (i) Determination of MIC using Vitek 2 automated
system to confirm resistance of Acinetobacter species to all
commercially available antibiotics, (ii) Broth micro-dilution
method (BMD) for determination of Tigecycline susceptibility,
and (iii) Determination of antimicrobial synergy by broth
micodilution (Checkerboard method).Vitek 2 system results showed that, all of the 100 isolates
were resistant to all antibiotics included in the study. On the
other hand, (100%) of the isolates were sensitive (S) to
Colistin.
As regards the results by Broth microdilution antibiotic
susceptibility method, all 100 isolates (100%) were resistant to
ampicillin/sulbactam, Meropenem and Ciprofloxacin, whereas
95 isolates (95%) were resistant to amikacin, whereas all 100
isolates (100%) tested sensitive to Tigecycline.
The results of the antibiotic combinations were as
follows; the activity of Ampicillin/sulbactam in combination
with Amikacin showed, Synery in (48%), Additivity in (42%)
and Indifference in (10%), the activity of Ampicillin/sulbactam
in combination with Ciprofloxacin showed, synergy in (36%),
Additivity in (52%) and Indifference in (12%), the activity of
Meropenem in combination with Amikacin showed, synery in
(26%), additivity in (53%) and Indifference in (21%), no
antagonistic activity was detected between any of the antibiotic
combinations used.
Concerning the relation between degree of resistance
(MIC value) and the activity of the different antibiotic
combinations used, the present study indicated that, as the MIC
value (degree of resistance) decrease, most of the results are
suscpected to have a synergic activity. On the other hand, as the
MIC value (degree of resistance) increase, most of the results
are suscpected to have an indifferent activity.Results of the clinical questionnaire done on the most
commonly used antibiotic combinations for patients with drug
resistant Acinetobacter spp. in critically ill patients admitted in
the ICUs showed that 9 out of 15 clinicians (60%), provide
Meropenem and Amikacin recommended combination therapy
for treating patients with drug resistant Acinetobacter spp., with
no significant improvement of patients to the given
combination (25%). On the other hand only 3 out of 15
clinicians (20%) stated that using Ampicillin/sulbactam and
Amikacin for treating those patients with improvement of
patients in (50%).
Finally the laboratory’s recommendations for antimicrobial
combinations in cases of drug resistant Acinetobacter spp.
infections has been updated for a clinical feedback on the most
synergic antimicrobial combination (Ampicillin/sulbactam and
Amikacin),removal of the least synergic combination
(Carbapenem and Amnoglycoside) and providing Tigecycline
as monotherapy.