الفهرس 
Materials and methodsOnly 14 pages are availabe for public view
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Abstract
Pe. ”erug.inosa has been considered to be one of
the causes of serious diseases in man and it infrequently
is the cause of infection in normal individuals unless they have suffered from ma~~r trauma or burns.
It is involved in respiratory. cutaneous and disseminated
infections in individuals who have defective host de f,mses of cutaneous batTLers, granulocytes or a mmuno-:
Several plasmids encoding resistance to one or more. antibioti.; could be identified from cl a n i ce l
isolates Ps. aeruginosd.
The present investigation was carried out in order to clarify the <Jenetic basis of Ps. aeruginosd ani:ibiotic
resistdnce. Five Ps. aeruginosa isolates were used. two isolates;
1 & 2 we re isolated from the urine of two patients with chronic urinary tract infection and three
lsolaLes. 3. 4, and 5, were isolated from patients with
cance, bladder. The results obt.ei no.t ,,:howedt.het all five: isolates
were equally sensitive to amikacin and were sensitive
to tobr-<lmycinwith d i f f crerrt degrees. The most resist-
ant isolate to tobramycl,-’W<l~J no. 1. The most resistant
isolate to kanarr~cin was isolate no. 1 followed by
isolate; 4,”3 and 5 res.:-,ectivelywhile isolate nc , 2
was sensitive. Also isolate no. 1 was highly resistant
to st,’eptomycin followed by isolates; 4. 5 and 3. respectIvely.
while isolate no. 2 was sensitive. The four Isolates; 1, 2. 4 and 5 were resistant to gentamicin.
Isolate no. 1 was the most resistant one to gentamicin
followed by isolate no. 4, while the isolates 2 and 5
were equal in their resistance to gentamicin and less
than isolate no. 4. Isolate no. 3 was sensitive on the
border line.
Isolate no. 1 which was resistant to the four
antibiotics had the lowe,,’::MIC of amikacin which
reached 50 ~g/ml followed by Tm and Gm which reached
for’ e it ner 400 ~g1m!. .•·.•hile those for Km and Sm more
than 400 ~g/rnl. MIC for isolate no. 2 to Am. Tm , Km ,
Sm and Gm were; 25. 50. 100. 200 and 100 ug/ml respectIvely.
Also MIC for isolate no. 3 to these antibiotics
wen:, 12.5, 10C, 400. >400 and 50 ~g/ml respectively.
for isolate no. 4 they were 25. 100. >400. >400. and 50
Ug/ml respectively and for isolate no 5 were; 12.5,
25. 100, 200 and 100 ~g/ml respectively.
Single colonies of isolate no. 1 c;howed great
variations in their levels of resistance to the different
antibiotics indicating that the resistant genes are
located in different plasmids. Isolate no. 2 single
colonies were similar in their resistance to gentamicin
levels indicating chromosomal mode of inheritance.
In isolate no. 3. Km and Sm resistant genes were encoded
by the same plasmids. Isolates no. 4 and 5 single
colonies showed different levels of resistance to. Km.
SOl and Gm with great agreement for resistance levels
indicating the existence of the genes in the same
plasmids. The percentages of E. coli k12 transformants which
resist 10 ~g/ml of each antibiotics ranged from 1
1.75 when plasmid DNA was used as donor. The highest
levels of resistance appeared for E. coli. k12 transformants
to streptomycin followed by those; Km. Gm and Tm respectively.
Transformation of the Gram positive S. aureus and
B. eubt il is with plasmid DNA isolated from Ps. aeruginosa
was unsuccessful.
E. coli k12 ~ransformants indicated that the
resistance to fun which can be acquired with a plasmid is probably 10 ~g Km/ml medium. The
of 50 ~g Km resistance can be obtained from dose of plas~id as no. 20. 30 or 40 ~g Km/ml lowest single level double
r”,o,isLance could be ”btained. This increase in the
double dose had been attributed to gene interactions
and c;~n~ regulatory mechanisms. Tree plasmids were
respo”sible for the level of kanamycin resistance
reclched 100 I1g/ml, 4 plasmids for the level of 200 I1g/ml. One plasmids tively.
Each plasmid gave a resistance level of I1g medium. The possibility of gene interactions can
be eXIsted. the same c.lppeClredfor tobramycin.
Positive correlation between bilharzia.
plasmid was estimated to give 50 I1g Sm/ml levels, 2 for the level of 100 I1g, 3 and 4
for the levels of 150 and 200 I1g/ml res~ecl:~ esistance Gm/ml also cancer
high bacterial counts and high phage contents and no
clear correlation was noticed between phage contents
and the resistance of any of the antibiotics studied.
In conclusion plasmids play an essential role in
antibiotics resistance. To solve this problem it is
essential to look for plasmid curing. Curing can occur
spontaneously during growth and cell divisions or following
treatments with some agents such as elevated
temperatures. acridine hydrochloride. ascorbic acid and
the bes~ ~herapeutic tz”eatnents might be through safe
va cci net ioris.