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Molecular Identification of Methicillin-Resistant Staphylococcus aureus in Benin-City Nigeria

O Obasuyi

 

Abstract

We use the molecular techniques of PCR and PFGE to identify MRSA from clinical isolates of Staphylococcus aureus causing infections among hospitalized patients in Benin-City, Nigeria. A total of 36 isolates were obtained from the University of Benin Teaching Hospital between July-September, 2007. The MRSA strains were selected according to their phenotypic characteristics (antibiotic resistant profiles), susceptibility to oxacillin by E-test, and detection of β-lactamase. This was verified by a latex agglutination test for PBP2a production combined with PCR for mecA gene carriage. Four isolates representing 11% were confirmed as MRSA according to the molecular techniques used with two PFGE types (H and L) and one agr type (1). Multi resistance to the various antibiotics used was observed in one of the clones. The isolation of MRSA in health institution indicates that adequate steps in limiting spread are urgently needed. Also, for the first time two MRSA clones according to the PFGE classifications have been identified in Nigeria.

Keywords: methicillin-resistant Staphylococcus aureus, MRSA, PFGE, PCR, molecular techniques.

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Molecular Identification of Methicillin-Resistant Staphylococcus aureus in Benin-City Nigeria

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Global trend of Methicillin-resistant Staphlococcus aureus and emerging challenges for control

O Azeez-Akande

 

Abstract

Background: Following its first recognition in early 1960s, the increasing incidence of nosocomial and community-acquired methicillin resistant Staphylococcus aureus (MRSA) infections has become a global problem. The emergence of multiple-drug resistant MRSA strains and dissemination of epidemic antibiotic clones including presence of wide spectrum of virulence and predisposing risk factors complicate diagnosis, chemotherapy and control causing significant morbidity and mortality. Detection of MRSA strains in domestic animals and protozoan has widened the epidemiologic characters of the organism and may influence infection control policies. Objectives: To review the emergence and epidemiologic spread of resistant strains of MRSA, molecular/genetic basis of resistance in the organism and challenges facing control strategies worldwide. It also aims to suggest intervention strategies so as to checkmate the spread of MRSA infections.
Methods: By reviewing local and international literatures on MRSA infections coupled with practical experience in the field of this endeavour. Result/Conclusion: MRSA has shown increasing endemic and epidemic spread in the last four decades causing serious medical and socio-economic difficulties. Routine and regular surveillance (uncommon in poor-resourced developing areas of especially sub-Saharan Africa), good hospital practices and personal hygiene, public enlightenment, development of effective therapeutic agents and rational administration of antibiotics based on reliable test results will limit the spread of MRSA infections.

Key words: MRSA, incidence, morbidity, mortality, surveillance, control.

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Global trend of Methicillin-resistant Staphlococcus aureus and emerging challenges for control

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Characteristics of Nosocomial MRSA in Assir Central Hospital, Abha, Kingdom of Saudi Arabia

T Al-Azraqi, CSS Bello

 

Abstract

The objective of this study is to determine the characteristics of nosocomial methicillin-resistant and sensitive Staphylococcus aureus (MRSA & MSSA) and their minimum inhibitory concentration (MIC) to vancomycin and oxacillin. Over a six-month period a study of Staphylococcus aureusisolates from clinical specimens of patients with nosocomial infections in Assir Central Hospital (ACH), Abha, Saudi Arabia, between September 2003 and February 2004, was carried out. Isolation and identification of Staphylococcus aureus was performed using standard microbiological methods. MIC to vancomycin and oxacillin was carried out using the E-test strips. Eighty-five Staphylococcus aureus isolates were identified. These were made up of 39 (45.9%) MRSA and 46 (54.1%) MSSA. The MIC to oxacillin showed that 37/39 (94.9%) MRSA had MIC >256 µg/ml and only 2/39 (5.1%) had MIC of 4 and 32 µg/ml. Thirty of forty six (65.2%) of the MSSA had MIC < 0.50 µg/ml and 16/46 (34.8%) had MIC of between 0.50 -2 µg/ml. All the 85 isolates were fully sensitive to vancomycin (MIC breakpoint < 4 µg/ml). There is even distribution of sensitivity pattern to vancomycin among MRSA and MSSA isolates. 31/39 (79.5%) of MRSA had MIC of 2 µg/ml while 34/46(74.0%) of MSSA had MIC of 2 µg/ml. The prevalence of MRSA in nosocomial infections in ACH is 45.9%. Thirty-seven out of thirty-nine (94.9%) of the MRSA strains show high resistance to oxacillin (MIC > 256 µg/ml). The use of oxacillin-related drugs to treat nosocomial Staphylococcal infections in ACH should be reviewed and infection control practices should be intensified so as to stem any future increase in MRSA prevalence in the hospital.
Key words: MRSA, Characteristics, MICs, Vancomycin, Oxacillin.Afr. J. Clin. Exper. Microbiol. 2005; 6(2): 163-166

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