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OJHAS Vol. 8, Issue 3: (2009
Jul-Sep) |
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Significance of Screening for Colonization and Vancomycin Resistance in
Staphylococcus aureus Isolated from Anterior Nares of School
Going Children |
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Ramana KV,
Dept. of Microbiology, Apollo Hospitals, Jubilee Hills,
Hyderabad,
Ratna Rao,
Senior Consultant, Apollo Hospitals, Jubilee Hills,
Hyderabad, |
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Address For Correspondence |
Research scholar,
Dept. of Microbiology,
Apollo Hospitals,
Jubilee Hills, Hyderabad.
E-mail:
ramana_20021@rediffmail.com |
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Ramana KV, Rao R. Significance of Screening for Colonization and Vancomycin Resistance in
Staphylococcus aureus Isolated from Anterior Nares of School
Going Children. Online J Health Allied Scs.
2009;8(3):20 |
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Submitted: July 12, 2009; Accepted:
Sep 10, 2009 Published: Nov 15, 2009 |
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| Abstract: |
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No abstract
Key Words:
Staphylococcus aureus,
Colonization, Vancomycin resistance
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Staphylococcus aureus infections form a major part of hospital
acquired infections.1 Although 20-40% of healthy individuals
carry S. aureus in the anterior nares, it continues to be a major
cause of both hospital and community acquired infections around the
world. S. aureus, not only has a unique epidemiological pattern,
but also can develop resistance to antibiotics. Because of its exceptional
ability to colonise patients and healthy individuals, it is responsible
for wide spread epidemics. In late 1930’s, when Sulphonamides offered
the first challenge to S. aureus infections and later in the early
1940’s by Penicillins, over a period of time, S. aureus is constantly
emerging resistant to a wide variety of antibiotics such as Semisynthetic
Penicillins,aminoglycosides, macroloides,quinolones, glycopeptides and
many other class of antibiotics.2 For more than three decades, vancomycin has
been a reliable treatment for multidrug resistant S. aureus infections. But with the discovery of S. aureus strains with reduced susceptibility to Vancomycin in 1996
in Europe, Asia and US, hinders our efforts to clarify the effectiveness
of Vancomycin in the treatment of Staphylococcal infections.
Of late there have been increasing reports of Vancomycin intermediate
(VISA) and Vancomycin resistant (VRSA) Staphylococal strains both in
hospital and community.3
There are growing reports of treatment failures with vancomycin since
NCCLS disk diffusion and stokes methods for antibiotic susceptibility
testing are not accurate predictors of reduced Vancomycin Susceptibilities
in Staphylococci and due to the inability of laboratories to differentiate
between vancomycin susceptible S. aureus strains(MIC<4µg/ml)
that have Vancomycin resistant subpopulations(1 in 108CFU/ml).
We collected 392 anterior nares swabs from schoolgoing children and
isolated 63 S. aureus isolates.The antimicrobial susceptibility
testing by Agar dilution method was performed on all isolates and the
control strains tested included Staphylococcus aureus ATCC 24923,Pseudomonas
aeruginosa ATCC 27853,E. coli
ATCC 25922
The test was considered
valid only when the MIC’s of the control strains were in the range
given by NCCLS standards.4 The results of the study indicate
colonization rates of 16% and the MIC’s of vancomycin were found to
be 0.5-2µg/ml. The results of our study though indicate a carriage rate
of 16%, the significant finding of the study is the occurrence of strains
with MIC’s of 1-2µg/ml which are responsible for treatment failures
that may contain Vancomycin resistant subpopulations which if are not
recognized and contained, can spread and lead to large scale outbreaks.
Growing number of infections by multidrug resistant S. aureus
and a discernible increase in Vancomycin use eventually leading to emergence
of VRSA.5
We suggest that inappropriate and indiscriminate use of antibiotics
should be avoided and stress the importance of rational use of
antimicrobial agents,use of standard methods for antimicrobial
susceptibility testing, frequent monitoring of community isolates for
colonization and their antibiotic resistance to win the war against
emerging multi drug resistance.
- Lowy FD. Staphylococcus
aureus infections. N Engl. J. Med 1998;339:520-532.
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William Beumfitt, Jeremy
Hamilton-Miller. Methicillin-Resistant Staphylococcus aureus. NEJM. 1989;320(18):1188-1196.
- Fridkin SC. Vancomycin intermediate
and resistant Staphylococcus aureus: what the infectious disease
specialist need to know. Clin. Infect. Dis. 2003;32:108-115.
- Clinical Laboratory Standards Institute. Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria that Grow Aerobically: Approved Standard. Eight edition.
CLSI document M07-A8(ISBN 1-56238-689-1. Clinical Laboratory Standards Institute, 940 West Valley Road, Suite 1400, Wayne, Pennsylvania 19087-1898 USA,2009
- Onanuga A, Oyi AR, Olayinka BO,
Onaolapo JA. Prevalence of community associated multi-resistant Staphylococcus aureus
among healthy women in Abuja, Nigeria. African Journal of Biotechnology
2005;4(9):942-945.
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