Inactivation of the pgmA Gene in Streptococcus mutans Significantly Decreases Biofilm-Associated Antimicrobial Tolerance

TY - JOUR

T1 - Inactivation of the pgmA Gene in Streptococcus mutans Significantly Decreases Biofilm-Associated Antimicrobial Tolerance

AU - Nilsson, Martin

AU - Givskov, Michael

AU - Twetman, Svante

AU - Tolker-Nielsen, Tim

PY - 2019/9

Y1 - 2019/9

N2 - Screening of a Streptococcus mutans mutant library indicated that pgmA mutants displayed a reduced biofilm-associated tolerance toward gentamicin. The biofilms formed by the S. mutans pgmA mutant also displayed decreased tolerance towards linezolid and vancomycin compared to wild-type biofilms. On the contrary, the resistance of planktonic S. mutans pgmA cells to gentamycin, linezolid, and vancomycin was more similar to wild-type levels. Investigations of biofilms grown in microtiter trays and on submerged glass slides showed that pgmA mutants formed roughly the same amount of biofilm as the wild type, indicating that the reduced antimicrobial tolerance of these mutants is not due to diminished biofilm formation. The pgmA gene product is known to be involved in the synthesis of precursors for cell wall components such as teichoic acids and membrane glycolipids. Accordingly, the S. mutans pgmA mutant showed increased sensitivity to Congo Red, indicating that it has impaired cell wall integrity. A changed cell wall composition of the S. mutans pgmA mutant may play a role in the increased sensitivity of S. mutans pgmA biofilms toward antibiotics.

AB - Screening of a Streptococcus mutans mutant library indicated that pgmA mutants displayed a reduced biofilm-associated tolerance toward gentamicin. The biofilms formed by the S. mutans pgmA mutant also displayed decreased tolerance towards linezolid and vancomycin compared to wild-type biofilms. On the contrary, the resistance of planktonic S. mutans pgmA cells to gentamycin, linezolid, and vancomycin was more similar to wild-type levels. Investigations of biofilms grown in microtiter trays and on submerged glass slides showed that pgmA mutants formed roughly the same amount of biofilm as the wild type, indicating that the reduced antimicrobial tolerance of these mutants is not due to diminished biofilm formation. The pgmA gene product is known to be involved in the synthesis of precursors for cell wall components such as teichoic acids and membrane glycolipids. Accordingly, the S. mutans pgmA mutant showed increased sensitivity to Congo Red, indicating that it has impaired cell wall integrity. A changed cell wall composition of the S. mutans pgmA mutant may play a role in the increased sensitivity of S. mutans pgmA biofilms toward antibiotics.

KW - Streptococcus mutans

KW - pgmA

KW - biofilm

KW - antimicrobial tolerance

U2 - 10.3390/microorganisms7090310

DO - 10.3390/microorganisms7090310

M3 - Journal article

C2 - 31484288

SN - 2076-2607

VL - 7

JO - Microorganisms

JF - Microorganisms

IS - 9

M1 - 310

ER -