Z. Sekawi

International Journal of Infectious Diseases

Sekawi, Z.

Elsevier - Publisher Connector 

Toxin antitoxin system as an antimicrobial target for antibiotic resistant Staphylococcus aureus 

Directory of Open Access Journals

Toxin antitoxin system as an antimicrobial target for antibiotic resistant Staphylococcus aureus

90 16th ICID Abstracts / International Journal of Infectious Diseases 21S (2014) 1–460
Type: Poster Presentation
Final Abstract Number: 40.026
Session: Antibiotic Resistance
Date: Thursday, April 3, 2014
Time: 12:45-14:15
Room: Ballroom
Demographic and microbiological proﬁle of
cystic ﬁbrosis in Durban, South Africa
N. Mhlongo1, U. Govinden1, J. Egner2, S.
Essack1,∗
1 University of KwaZulu-Natal, Durban, South Africa
2 Netcare, St Augustine’s Hospital, Durban, South
Africa
Background: Cystic ﬁbrosis necessitates long-term treatment
with multiple antibiotics creating selection pressure for the devel-
opment of antibiotic resistance in infecting and/or colonizing
organisms, impacting on diseasemanagement,morbidity andmor-
tality.
Methods & Materials: Sputum samples were obtained from
patients attending the only two CF clinics in Durban over a year.
Thepatientdemographicsandclinicaldatawere recorded.Bacterial
isolates were subjected to identiﬁcation, susceptibility testing and
phenotypic screening for extended spectrum-lactamases (ESBLs),
AmpC -lactamases and metallo--lactamases (MBLs).
Results: A total of 25 patients constituted the study sample.
The most common genotype was F508 and the most common
pathogen was P. aeruginosa with susceptibility to antibiotics ran-
ging from 14-100% with marginal differences between mucoid and
non-mucoid phenotypes. All P aeruginosa isolates were putative
ESBL producers and 75% were putative MBL producers.
Conclusion: The incidence, prevalence and susceptibility pat-
terns of bacterial pathogens and colonizers isolated from cystic
ﬁbrosis patients should be closely monitored to optimize man-
agement and treatment options in a disease requiring chronic
antibiotic therapy which increases the propensity for the devel-
opment of antibiotic resistance.
http://dx.doi.org/10.1016/j.ijid.2014.03.616
Type: Poster Presentation
Final Abstract Number: 40.027
Session: Antibiotic Resistance
Date: Thursday, April 3, 2014
Time: 12:45-14:15
Room: Ballroom
Toxin antitoxin system as an antimicrobial
target for antibiotic resistant Staphylococcus
aureus
Z. Sekawi
University of Putra Malaysia, Putra, Malaysia
Background: Toxin antitoxin (TA) system is deﬁned as a reg-
ulator system consisting of toxin that is neutralized by cognate
antitoxin. TA systems have been characterized in a small number
of Methicillin Resistant Staphylococcus aureus, Vancomycin Resis-
tant Enterococcus, and Pseudomonas aeruginosa. The prevalence
of TA system in a large number of independently isolated clini-
cal isolates of antibiotic resistant S. aureus from diverse locations
is determined, then functionality of dominant TA system is evalu-
atedand theantitoxin is subjected for silencingbyantiMazEPeptide
Nucleotide Acid (PNA) subsequently the suicide of bacteria by toxin
is determined.
Methods & Materials: It probed total chromosomal and plas-
mid DNA obtained from 1000 S. aureus clinical isolates from Milad
hospital in Iran and 60 MRSA clinical isolates from Hospital Kuala
Lumpur in Malaysia for the presence of TA loci. for Identiﬁcation of
TA loci PCR were performed with chromosomal and plasmid DNA.
functionality was evaluated by qPCR, ATPase and turbidity assayes
and then the antitoxin was scilenced by PNA assay.
Results: Sequences for one particular TA pair, the MazEF TA sys-
tem, were present on plasmid of all antibiotic resistant S. aureus
in Milad hospital and MRSA in HKL. Additionally, RT-PCR analy-
sis revealed that the transcripts were produced from MazEF loci,
suggesting that these loci are functional in the clinical isolates.
Also, toxin transcript expression levelswere increasedwhenbacte-
ria were grown under stressful conditions. Furthermore, stress
decreased cellularATP levels consistentwithMazF toxin expression
and activity. The ATP results were conﬁrmed by turbidity analysis.
The PNA was designed for speciﬁc target of MazE antitoxin and the
results revealed thatMazEbe silencedwith 30mof antiMazEPNA.
The ﬁnding showed that the MazF toxin killed S. aureus containing
MazEF TA loci.
Conclusion: So, these results indicate that MazEF TA genes are
prevalent and functional within a large proportion of S. aureus
clinical isolates, and their role in stress tolerance, plasmid or chro-
mosome location, silencing by PNA and toxic effect of the MazF
toxin against bacterial cells recommended the MazEF TA system is
a sensitive target for eradication of antibiotic resistant S. aureus.
http://dx.doi.org/10.1016/j.ijid.2014.03.617
Type: Poster Presentation
Final Abstract Number: 40.028
Session: Antibiotic Resistance
Date: Thursday, April 3, 2014
Time: 12:45-14:15
Room: Ballroom
Penicillin susceptibility of pediatric Carriage
pneumococci, Lower Sindh, Pakistan
S. Shakoor1, S.-E.-Z. Zaidi1, A. Hotwani1,∗, F.
Jehan1, I. Nisar1, S. Qureshi1, A. Zaidi2
1 Aga Khan University, Karachi, Pakistan
2 Aga Khan University Hospital, Karachi. Pakistan,
Karachi, Pakistan
Background: S. pneumoniae is the main cause of community
acquired pneumonia andmeningitis in children in Pakistan, and
rates of antibiotic resistance have increased dramatically in the
last few years. Recent recommendations by the IDSA and revision
of breakpoints by CLSI imply that penicillin be the cornerstone
of treatment for pneumococcal disease (except meningitis). It is
therefore essential to determine penicillin and ceftriaxone suscep-
tibility of carriage pneumococci which lead to invasive disease by
translocation. Susceptibility testing of carriage isolates predicts the
sensitivity and therefore feasibility of empiric treatment of pneu-
mococcal disease.
We determined the antibiotic susceptibility (AST) and mini-
mum inhibitory concentrations (MICs) of Penicillin andCeftriaxone


file:///data/remote/core/dit/data/elsevier/pdf/b2b/aHR0cDovL2FwaS5lbHNldmllci5jb20vY29udGVudC9hcnRpY2xlL3BpaS9zMTIwMTk3MTIxNDAwNjc2Ng==.pdf

Toxin antitoxin system as an antimicrobial target for antibiotic resistant Staphylococcus aureus

Abstract

Similar works

Full text

Available Versions

Elsevier - Publisher Connector

Directory of Open Access Journals

Elsevier - Publisher Connector