الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
SUMMARY
SUMMARY
Nosocomial infections represent a major hazard In health care
facilities, their effects are on the infected patients, their families and the
health care system.
Increasingly, microbes are becoming resistant to a substantial
proportion of drugs which considered the first line treatment, this often
necessitate the use of more costly antimicrobial agents. Such resistance is
having an impact not only on the therapy of the individual patients but
also on the infection control in the hospital.
Automation was introduced into the clinical microbiology
laboratory in the late 1960s. Since that time improvement in technology
and the introduction of computerized data analysis have made
mechanization practical and allowed its applications to expand. Today
instruments have many uses in the microbiology laboratory as isolation
and detection of organisms in clinical specimens, identification of isolates
and testing the susceptiblity of isolates to antimicrobial agents.
The purpose of the present study was to identify current
nosocomial pathogens. It also aimed to compare species identification
obtained by Microscan Walkaway 40 and Sensititre autoreader system
with those obtained by conventional methods (routine tube biochemical
tests and BBL crystal enteric non fermenter ID kit in case of gram
negative bacilli and catalase, coagulase, DNase, bacitracin, bile solubility
and streptex in case of gram positive cocci) to devise a method for the
identification which is technically simple, accurate and rapid.
SUMMARY
This study was conducted on 200 specimens from patients with
nosocomial infections from May 2000 to April 200 I .
The specimens included: 79 urine sample, 62 pus sample, 33 blood
sample and 26 sputum sample.
All specimens were subjected to the followings:
- Direct stained smear.(except blood samples).
- Isolation of the organism by culture on ordinary media.
- Viable bacterial count. (for urine samples).
- Gram stained smear for the islated organism.
For gram negative bacilli, the identification was done by
A-Conventional method:
1- Traditional tube biochemical reactions.
2- BBL crystal TM identification system (Enteric/ Non fermenter)
(Becton Dickinson)
B-Automated methods:
- Dade Behring Microscan Walkaway 40.
- Accu - Med - Inc, Sensitire.
For gram positive cocci, the identification was done by :
A-Conventional methods [Catalse, coagulase, DNase, bacitracin, bile
solubility and streptex (Murex biotech limited)].
B-Automated systems (Microscan Walkway 40 and Sensititre).
For testing susceptibility:
- Conventional disc diffusion (for both gram negative bacilli and gram
positive cocci).
SUMMARY
- Automated system (Microscan Walkaway 40 and Sensititre systems)
for both gram negative bacilli and gram positive cocci.
• Gram negative bacilli were isolated from 78% of specimens collected
from patients with nosocomial infections, while gram positive cocci
were isolated from 22% of these specimens.
• Proteus group was the most common gram negative pathogen isolated
in the study, while Staph.aureus was the commonest gram positive
pathogen.
• E.coli and Proteus groups were equall causes for nosocomial urinary
tract infection (32.4% - 24 out of79 for each).
• Pseudomonas group was the commonest pathogen causing nosocomial
wound infection in our study (33.3% - 19 out of 62).
• However, in blood stream and respiratory tract infections, Klebsiella
group was the most frequent (21.2% - 7 out of33 and 30.8% 8 out of
26 respectively).
• The predominant types of nosocomial infections caused by gram
positive cocci were the urinary tract and wound infections (16 cases
for each - 36.4%).
• Blood stream and respiratory tract infections come in the subsequent
order of frequency.
• Coagulase negative staph was the most common gram positive
pathogen causing urinary tract infection (13.9% - 11 out of 79), while
Staph.aureus was the most common one in wound infection (16.1% _
10 out 62»
• The agreement between the Sensititre Ap 80 plate identification and
that of conventional system identificatio,n for members of the family
SUMMARY
enterobacteriacae was 97.4% at the genus level and 93.4% at the
species level.
• However the agreement between the two methods for non
enterobacteriacae group was 91.7% at both the genus and species
level.
• The agreement between the results of Microscan conventional
negative panel and that of conventional system identification for
members of enterobacteriacae was 97.4% at the genus level and 96%
at the species level.
• However the agreement between the two methods for non
enterobacteriacae group was 95.8% at the genus level and 91.7% at
the species level.
• Imipenem was the most effective antibiotic against members of the
family enterobacteriacae isolated in the study (81.6% susceptible by
DD).
• Amikacin and imipenem were the most effective antibiotics against
members of non enteriobacteriacae group isolated in the study (62.5%
susceptible for each).
• The highest precent of resistance for the enterobacteriacae group
oCcurred with ampicillin (92.1 %), followed by nitrofurantoin (90%),
while for non enterbacteriacae group occurred also with ampicillin
(95.8%) followed by cefazoline and trimethoprim / sUlfamethoxyzole
(91.7% for each).
• The agreement between the results of Microscan gram negative
breakpoint combo panel and that of disc diffusion was 98.6% for
””’201 ••
SUMMARY
members of enterobacteriacae and 97.2% for members of non
enterobacteriacae group.
• The agreement between the results of Sensititre breakpoint autoreader
system and that of disc diffusion method was 98.2% for
enterobacteriacae and 96.7% for members of non enterobacteriacae.
• Vancomycin was the most effective antibiotic against gram positive
isolates (97.5% susceptible) followed by imipenem (82.5%
susceptible.
• The agreement between the results of Microscan gram positive
breakpoint combo panel and that of disc diffusion method was 98.7%
and the agreement between the results of Sensititre system and that of
disc diffusion method for antibiotic susceptibility of gram positive
isolates Was 98.5%.