Biomaterial Database

Interaction between methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA). 2003

G Gopal Rao, and J Wong

Department of Microbiology, University Hospital Lewisham, London SE13 6LH, UK. gopal.rao@uhl.nhs.uk

In this paper we describe the in vitro interaction between three strains of methicillin-sensitive Staphylococcus aureus (MSSA) [NCTC 11561 and two strains derived from patients (PMSSA)] and endemic methicillin-resistant Staphylococcus aureus (EMRSA) 1, 3, 15 and 16. Mixed bacterial cultures of MSSA and EMRSA were incubated and subcultured after one, two and seven days. A proportion of MRSA in 50 randomly selected colonies was assessed. All strains of EMRSA (EMRSA 1, 3, 15 and 16) outgrew and virtually eradicated MSSA (NCTC 11561) after 24 h. The interaction between strains of PMSSA and the various strains of EMRSA was variable. PMSSA strain 1 was almost completely outgrown by EMRSA 1 and EMRSA 3 after seven days. Similarly there was a substantial increase of EMRSA 1 and 3 when tested against PMSSA strain 2. EMRSA 15 increased modestly against both strains, but EMRSA 16 failed to increase in proportion against either of the strains. We conclude that there is a complex interaction between various strains of EMRSA and MSSA. This interaction may have an important bearing on colonization of patients with MRSA.

UI	MeSH Term	Description	Entries
D000898	Antibiosis	A natural association between organisms that is detrimental to at least one of them. This often refers to the production of chemicals by one microorganism that is harmful to another.	Bacterial Interference,Microbial Antagonism,Interference, Bacterial,Antagonism, Microbial,Antagonisms, Microbial,Antibioses,Bacterial Interferences,Interferences, Bacterial,Microbial Antagonisms
D013211	Staphylococcus aureus	Potentially pathogenic bacteria found in nasal membranes, skin, hair follicles, and perineum of warm-blooded animals. They may cause a wide range of infections and intoxications.
D015169	Colony Count, Microbial	Enumeration by direct count of viable, isolated bacterial, archaeal, or fungal CELLS or SPORES capable of growth on solid CULTURE MEDIA. The method is used routinely by environmental microbiologists for quantifying organisms in AIR; FOOD; and WATER; by clinicians for measuring patients' microbial load; and in antimicrobial drug testing.	Agar Dilution Count,Colony-Forming Units Assay, Microbial,Fungal Count,Pour Plate Count,Spore Count,Spread Plate Count,Streak Plate Count,Colony Forming Units Assay, Microbial,Colony Forming Units Assays, Microbial,Agar Dilution Counts,Colony Counts, Microbial,Count, Agar Dilution,Count, Fungal,Count, Microbial Colony,Count, Pour Plate,Count, Spore,Count, Spread Plate,Count, Streak Plate,Counts, Agar Dilution,Counts, Fungal,Counts, Microbial Colony,Counts, Pour Plate,Counts, Spore,Counts, Spread Plate,Counts, Streak Plate,Dilution Count, Agar,Dilution Counts, Agar,Fungal Counts,Microbial Colony Count,Microbial Colony Counts,Pour Plate Counts,Spore Counts,Spread Plate Counts,Streak Plate Counts
D016106	Methicillin Resistance	Non-susceptibility of a microbe to the action of METHICILLIN, a semi-synthetic penicillin derivative.	Methicillin-Resistant,Methicillin Resistant,Resistance, Methicillin