THE EFFECT OF SUBMINIMUM INHIBITORY CONCENTRATION OF ROCEPHIN(R) ON TWO ISOLATES OF PSEUDOMONAS AERUGINOSA
THE EFFECT OF SUBMINIMUM INHIBITORY CONCENTRATION OF ROCEPHIN(R) ON TWO ISOLATES OF PSEUDOMONAS AERUGINOSA
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Date
1988-10
Authors
JAMIU, OLADAPO SALAMI
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Abstract
ABSTRACT
THE EFFECT OF SUBMINIMUM INHIBITORY CONCENTRATION
OF ROCEPHIN(R) ON TWO ISOLATES OF PSEUIOMONAS
AERUGINOSA
The effect of subminimum inhibitory concentration
(Sub M.I.C) of Rocephin(R) (Ceftriaxone) was tested on
two isolates (a clinical isolate and a wild type) of
Pseudomonas aeruginosa. The concentration tested has
little or no effect on the growth rate of these
isolates. The M.I.C of Rocephin(R) against the
clinical isolate was l80ug/ml and that agaiist the
wild was 300ug/ml. The subMIC used was 7.5ug/ml for
the clinical and 12.5ug/ml for the wild (which were
1/24 of the M.I.Cs).
It was found that there is a strain-dependent
optimum antibiotic concentration below the M.I.C for
maximal filamentation. The clinical isolate showed
greater filamentation with increasing antitiotic
concentration up to a point (l50ug/ml) whereas the
wild type showed increase in length of filament with
lowering antibiotic concentration, with optimum at
about 40ug/ml while being at the same time more
resistant than the clinical isolate.
The antibiotic untreated cells were more
phagocytosed by fresh human polymorphonuclear
-viiineutrophils
(PMN) in the exponential phase than in
the stationary phase for both isolates. Relatively,
the clinical isolate was more susceptible to
phagocytic uptake than the wild type in the
exponential phase. However, this relative
susceptibility was reversed in the stationary phase.
The two isolates were moderately hydrophobic with
the clinical isolate being more hydrophobic than the
wild type.
When the cells were treated with Rocephin(R)
at a concentration of 1/24 of M.I.C, there was an
increase in phagocytic uptake of both isolates at
both phases of growth and the observed effect of
phase of growth on relative susceptibility was
maintained. The subMIC also increased cell surface
hydrophobicity of both isolates, with increase in
the wild type being more than that of the clinical
isolate at both exponential and stationary phases
of growth. However, antibiotic treatment reversed
the order of relative hydrophobicity observed in
the untreated cells.
Serum increased cell surface hydrophobicity
of both isolates at both phases of growth but the
increase at the stationary phase was not as pronounced
-ixas
in the exponential phase. When the cells were
treated with Rocephin and serum together there
was a general increase in the hydrophobicity at
both phases of growth, greater than when the cells
were treated with either the antibiotic or serum
alone. However, this combination nullified the
reversal of relative hydrophobicity between the
isolates observed with Rocephin(R) alone, in
favour of the clinical isolate.
When the ability of the isolates to adhere
to surfaces was tested, the clinical isolate as
found to adhere less than the wild type in the
exponential phase, while in the stationary phase
the clinical isolate adhere more. However, the
effects of Sub M.I.C. of Rocephin(R), serum
individually and the combination of the two appeared
to be dependent on the cells, phase of growth and
the test material.
Description
A thesis submitted to the Postgraduate School, Ahmadu
Bello University, Zaria in partial fulfillment Of the
requirements for the award of the degree of MASTER OF
SCIENCE IN PHARMACEUTICAL MICROBIOLOGY
Keywords
EFFECT, SUBMINIMUM, INHIBITORY, CONCENTRATION, ROCEPHIN(R), ISOLATES, PSEUDOMONAS, AERUGINOSA