Salt‐Induced L‐Forms of Staphylococcus aureus

Abstract

When growing cultures of a salt-sensitive strain of Staphylococcus aureus were inoculated on nutrient agar containing 0.8MNaC1 and0.5% bovine serum albumin, typical colonies of L-form developed extensively after 2 days of incubation at 30 C. Incubation of growingCultures with lipoteichoic acid, sodium polyanethole sulfonate and subtilisin resulted in inhibition of L-form induction.

Cell wall deficiency and its effect on methicillin heteroresistance in Staphylococcus aureus

“…enhance the methicillin resistance expression especially in heterogeneous MRSA strains [10,11]. On the other hand, the L-form variant growth of S. aureus can appear under similar culture conditions where factors such as NaCl, antibiotics and composition of the medium are of special importance [12][13][14]. Thus, understanding the nature of methicillin 'heteroresistance' and its association with morphological cell wall variations as well as explaining the factors involved in the regulation of cell wall biosynthesis could be of use for control and screening of methicillin resistance in staphylococci.…”

Salt‐Sensitive Growth of Staphylococcus aureus: Stimulation of Salt‐Induced Autolysis by Multiple Environmental Factors

“…Certain strains, however, are evidently sensitive to NaCl and exhibit autolysis in the presence of a relatively low concentration of NaCl (4,10). According to Yabu et al, salt tolerance in salt-sensitive S. aureus 209P could easily be restored by autolysin inhibitors such as polyanetholesulfonate (PAS) or lipoteichoic acid (LTA) (10,11). It therefore seems likely that a salt-sensitive autolytic system is operating in salt-sensitive S. aureus (10,11).…”

“…According to Yabu et al, salt tolerance in salt-sensitive S. aureus 209P could easily be restored by autolysin inhibitors such as polyanetholesulfonate (PAS) or lipoteichoic acid (LTA) (10,11). It therefore seems likely that a salt-sensitive autolytic system is operating in salt-sensitive S. aureus (10,11). Although it has been established that NaCl activates the cell wall-lytic enzymes of staphylococcal cells (2,8), it is not at all clear why staphylococcal cell wall-lytic enzymes can properly operate under a wide range of ionic strength, and the regulatory system of the lytic enzymes, in itself, still remains equivocal.…”

Staphylococcus aureus Produces Autolysin‐Susceptible Cell Walls during Growth in a High‐NaCl and Low‐Ca2+ Concentration Medium

“…aureus IHM and S. aureus 209P exhibit an appreciable salt sensitivity in that the cells undergo autolysis during growth in the presence of a relatively low concentration (0.3-0.7M) of NaCl (6 , 24). S. aureus 209P is also known to develop L-form colonies on agar plates containing both bovine serum albumin and 0.8 M NaCl (25). Salt-induced autolysis in S. aureus 209P seems to be brought about by the activation of cell-associated autolysins since the occurrence of autolysis is effectively prevented by adding protease (subtilisin) to the culture medium, resulting in cells that have no salt-extractable autolysins (24) .…”