Antimicrobial resistance and molecular epidemiological characteristics of clinical

isolates of Staphylococcus aureus inChangsha area

Laura Restrepo Carvajal Sara Buelvas Molecular BiologyThird semester

STAFILOCOCUS

Gram-positive spherical cells with a diameter of 0.5 to 1.5 micrometers ,grouped irregularly, shaped bunches of grapes. usually catalase positive and non-encapsulated or limited capsule formation.

Positive catalase, aerobic , best pigment at room

temperature

INTRODUCTION

STAFILOCOCUS AUREUS

Also known as "golden staph" and Oro staphira, it is a facultative anaerobic Gram-positive coccal bacterium, positive catalase, positive coagulase.

Toxines and enzymes Coagulase positive Tipical lesion and other lesions

Resistance

B lactamases Resistance to methicillin, nafcillin, oxacillin and is independent of the production of β-

lactamases Resistance to Vancomicine

GENERAL GOAL

Recognize the genetic variability in clinical isolates of Staphylococcus aureus and its relationship with resistance

to methicillin and other antibiotics in the region of Changsha (China)

 

MÉTODOS

CEPAS

293 aislados Prueba coagulase positiva y sistema

Vitek 2

SUSCEPTIBILIDAD A ANTIMIOBIANOS

Metodo de difusión en disco ( CMI oxacilina)

Método de dilución en agar

PCR

Gen Fem Gen Mec

PFGE

Peso del DNA 115 aislados

RESULTADOS

293 cepas de S. aureus

Tasa de resistencia superior al 50% (14 de 23 antibióticos probados)

Resistencia a

Penicilina 96.6%

Ampicilina 96.6%

Eritromicina 77.1%

Clindamicina 67.2%

Susceptibilidad a Tecoplanin Vancomicina Linezolid

Aislamientos del Hospital de Xiangya altamente resistentes a mayoría de antibióticos probados

Prevalencia de MRSA en los años 2006- 66.7% 2007- 85% 2008- 63.1%

El total de cepas para la tipificación de PFGE fueron 115

Los 115 aislados fueron agrupados en 39 tipos con 13 patrones predominantes designados de la A a la M 89 aislados

PREVALENCIA

1. A 56,48.7%

2. L 5,43%

Los aislados tipo A presentaron 13 subtipos denominados de A1 a A13. Los mas frecuentes fueron:

1. A1 46.4% ……………..26/56

2. A2 13.3% ……………..8/56

3. A3 5.4% ……………..3/56

4. A4 12.5% …................7/56

5. A6 5.4% ……………..3/56

8 de 11 hospitales estudiados tienen cepas de S. Aureus con PFGE tipo A.

Subtipo A1 se presento en 6 hospitales

115 cepas

79 MRSA

56/79 tipo A23/79

Otros 13 tipos

36 MSSA

25 tipos

*sin predominio

*37/42 MRSA

DISCUSIONAuthors What did they

said?Yes or Not

Monnet, Voss , Krziwanek , Allerberger ,Struelens .

MRSA is at present the most commonly identified antibiotic-resistant pathogen in any parts of the world, including Europe, the Americas, North Africa, the Middle East, and Asia.

YES. In USA, some european contries and the prevalence is higher in the Asia Pacific region

Bianchi G, Qin D, Dearani JA, Qi Q The swiftly increasing rates of MRSA worldwide over thepast decades have become a serious public health

problem.

YES. The adverse effects of some treatments have disadvantages that could not be widly used in the treatment of severe infectious. This obligates to create stretegies that weren`t planned

Conceicao T, Aires-de-Sousa M, Fuzi M, Toth A, Paszti J,Ungvari E

These epidemic strainsmay cause outbreaks within a hospital or a region, ordisseminations between different hospitals, regions, orcountries.

YES. The fast spread of MRSA strains with the same clonal lineages between regions or continents is also a serious problem of particular concern.

Alp E, Klaassen CH, Doganay M, Altoparlak U, Aydin K,Engin A

Consistent with previousstudies that a single epidemic MRSA clone can bepresented in the same hospital for many years.

YES. A1 strains were isolated in 2006,2007and 2008 from many departments in Xiangya Hospital

CONCLUSIONS

• Indiscriminate use of antibiotics has contributed to the increase in infections caused by multiresistant microorganisms

• Every time there are more antibiotics that lose their functionality because the capacity that bacterias have to mutate and transfer genetic information is very high.

• The variation in the types of strides is the prove of the bacterias resistance.

• If the use of antibiotics is not controlled inmediatly in some years the infections may not have cure

Sara Buelvas

Laura Restrepo