14
Pereira et al., 2015 Short Communication/Comunicações Received 10 Jun 2015; Revised 15 Jun 2015; Accepted 20 Jun 2015; Published online: 12 Aug 2015
Received 29 Jun 2015;
Antimicrobial Susceptibility of Commercial Revised 13 Jul 2015; Accepted 20 Jul 2015; Probiotic Lactobacillus Strains Published online: Aug 2015 Nayara Gonçalves Pereira1, Flávio Júnior Barbosa Figueiredo2,4 Marcus Vinícius Dias-Souza3,4* 1 – PharmBSc, Health and Human Development Faculty, Santo Agostinho Institute, Minas Gerais, Brazil. 2 – Pharm.D, MSc, Microbiology Laboratory, Health and Human Development Faculty, Santo Agostinho Institute, Minas Gerais, Brazil. 3 – Pharm.D, Ph.D, Microbiology Department, Biological Sciences Institute, Federal University of Minas Gerais, Brazil. 4 – Integrated Pharmacology and Drug Interactions Research Group (GPqFAR), Brazil. * Corresponding author:
[email protected]
The intestinal microbiota plays an important role in normal gut function and
the
normal
microbiota
at
the
disrupted
ecological environment of the digestive tract3.
maintaining host health. Lactobacillus sp.
Nevertheless,
the
behavior
of
strains are lactic acid bacteria (LAB) and
Lactobacillus strains under the effects of
ubiquitous commensals of the normal human gut
antimicrobial drugs is poorly investigated, and it
microbiota,
is technically difficult to predict the results of
1
probiotics .
and
are
They
widely express
explored
as
adhesiveness
the
concomitant
use
of
lactobacilli
and
properties that enable them to inhibit the
antimicrobial drugs2-5. Thus, here we investigate
adhesion of bacterial pathogens to host cells, can
the susceptibility of commercial Lactobacillus
produce biosurfactants, bacteriocins and other
strains to antimicrobial drugs widely used in
natural antibiotic molecules, and enhance
hospital and homecare treatments of infectious
immunological mechanisms against pathogens.
diseases in Brazil.
Commercial strains - isolated or in blends - are
Three comercial strains were used for
available as nutritional supplements or even as
this survey. Freeze dried aliquots of L.
medication, and both can be purchased without
paracasei (SKL Pharma, Brazil) L. rhamnosus
need
and L. acidophilus (Pharma Nostra, Brazil) were
of
medical
prescription
in
several
1,2
countries .
activated in MRS broth (Becton Dickinson,
A common application of probiotic
USA) in anaerobic jars for 48 h at 37 °C and
lactobacilli strains is the administration to
then cultivated in MRS agar plates (Becton
patients that are undertaking antimicrobial
Dickinson, USA), in order to be used to prepare
drugs in order to overcome side effects such as
bacterial suspensions in McFarland 0.5 scale. As
vomiting, and to provide some recovering of
no standards exist for susceptibility testing of
Journal of Applied Pharmaceutical Sciences – JAPHAC, 2015; 2(2): 14-17.
15
Pereira et al., 2015 lactobacilli, the following conditions were found demonstrated resistance of LAB to most of the to ensure confluent growth and thereby optimal
drugs we tested. It is desirable that probiotic
susceptibility testing: a total of 100 μL of a
bacteria resist to exposure to antimicrobial
suspension with density of McFarland 0.5 in
drugs, such that they can be co-administered.
0.9% saline was spread on MRS agar plates
L. rhamnosus strain was the only one
(MRS agar was used in order to ensure good
that was susceptible to all tested drugs and
growth of the strains, as the standard Mueller
large inhibition zones were detected; therefore,
Hinton agar failed to do so) and the following
it is possible that the administration of this
antimicrobial disks (all from Sensifar, Brazil)
strain and the tested antimicrobials will result
were used: Ampicillin (10 μg), meropenen (10
in
μg), gentamycin (10 μg), chloramphenicol (30
administrating the LAB. Nevertheless, in vivo
μg), levofloxacin (5 μg), ciprofloxacin (5 μg),
experiments are needed for confirmation of this
norfloxacin (10 μg), erythromycin (15 μg),
hypothesis.
poor
probiotic
effects
expected
after
nitrofurantoin (300 μg), and sulfamethoxazole-
Interestingly, L. acidophilus and L.
trimethoprim (25 μg). The plates were then
paracasei strains were not susceptible to
incubated in anaerobic jars (microaerophilic
quinolones, what suggest that they might be
environment) for 24 h at 37 °C, and inhibition
useful
zones were measured.
treatment of urinary tract infections and other
for
Results are summarized in table 1. Our
conditions
study shows different features of others that
quinolones
patients
such
as
are
in
sinusitis, first-choice
Table 1 – Antimicrobial susceptibility results Antimicrobial L. rhamnosus L. acidophillus L. paracasei Drug GEN
35
0
0
MER
50
29
40
AMP
35
22
26
SUT
40
0
0
LEV
42
0
0
CHLO
32
26
26
ERI
35
23
30
NIT
23
26
22
CIP
42
0
0
NOR
42
0
0
GEN: Gentamicin; MER: Meropenem; AMP: Ampicillin; NIT: Nitrofurantoin; SUT: Sulphamethoxazole-trimethropim; LEV: Levofloxacin; CHLO: Chloramphenicol; ERI: Erithromycin; CIP: Ciprofloxacin; NOR: Norfloxacin. Average measurements of inhibition zones are expressed in mm. Experiments were performed in duplicate.
Journal of Applied Pharmaceutical Sciences – JAPHAC, 2015; 2(2): 14-17.
pharmacological
in
which drugs.
16
Pereira et al., 2015 Also, L. acidophilus and L. paracasei strains were not susceptible to gentamicin and to
antimicrobial drugs is often species-dependent among Lactobacillus gender5-7.
Sulphamethoxazole-trimethropim.
Gentamicin
is
a
broad
Certain limitations can be mentioned
spectrum
to antimicrobial susceptibility of LAB. MRS
aminoglycoside that work by binding to the
agar has been used in similar researches
bacterial
worldwide, but little is still known about the
30S ribosomal subunit, causing
misreading
of
t-RNA,
protein
interaction of MRS and antimicrobial drugs.
synthesis. As aminoglycosides are generally
There is still a lack of agreement on the
ineffective against anaerobic bacteria, this
interpretative breakpoints for probiotic bacteria,
resistance
and
was
imparing
somehow
expected.
antimicrobial
susceptibility
data
of
Sulfamethoxazole is a bacteriostatic drug that
Lactobacillus
inhibits bacterial synthesis of dihydrofolic acid
criteria for susceptibility tests are not available
by competing with para-aminobenzoic acid for
until the preparation of this manuscript, what
binding
makes it difficult to define drug resistance
to
the
enzyme
dihydrofolate
synthetase. Trimethoprim is a dihydrofolate reductase
scarce. Suitable
patterns6.
the
acid
to
as an alternative to overcome this difficulty,
tetrahydrofolic acid. Bacterial resistance tend
but non-parameterized MICs and breakpoints
to be slower when these drugs are used in
are still a technical problem4-7. Given these
combination6,7.
situations, the scientific community expects
of
which
are
impairs
reduction
inhibitor,
strains
dihydrofolic
Broth microdilution has been explored
The alteration of the intricate networks
that the CLSI, EUCAST and other expert
of the normal gut microbiota by antimicrobial
committees on antimicrobial testing provide
use is a well recognized condition, and
soon the needed parameters for antimicrobial
ingested probiotics can help the organism to
susceptibility of these bacteria, given their
reestablish Antimicrobial
the
normal
susceptibility
3
microbiota . testing
clinical relevance as probiotics.
of
lactobacilli is important for checking the biosafety of potential probiotic strains for
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