Cell surface characteristics of coagulase-negative staphylococci and their adherence to fluorinated...

The ability of 21 nonencapsulated and 15 encapsulated coagulase-negative staphylococci (CNS) to adhere to xylene in xylene-water emulsions and to fluorinated poly(ethylenepropylene) (FEP) films revealed remarkable differences. Nonencapsulated CNS strains adhered well to FEP, whereas their adherence to xylene ranged widely. Encapsulated strains with low adherence to xylene showed slight adherence to FEP. Encapsulated strains which adhered well to xylene ranged widely in their adherence to FEP. It was concluded that results obtained from the xylene adherence test were not predictive of the adherence of CNS to the hydrophobic FEP surface. The number of nonwashed, slime-producing CNS strains adhering to FEP was similar to that of washed bacteria of the same strains. Bacterial adherence to FEP was decreased when FEP films were exposed to a solution containing extracellular products (EP) obtained from a slime-producing CNS strain. Bacterial adherence to xylene also decreased when the bacterial suspensions contained EP. Apparently, initial adherence of CNS to FEP and xylene is hampered by EP. Nonencapsulated and encapsulated CNS pretreated with proteolytic enzymes failed to adhere to xylene and FEP, indicating that intact surface proteins or constituents associated with surface proteins mediated their adherence to xylene and FEP. Freeze-etch replicas of a CNS strain adhering to FEP showed a smooth, flattened area on the bacterial surface at the contact site of the bacteria with the FEP, indicating that an external layer was present at the bacterial surface.