[Role of Ph-SA in enhancing bactericidal activity of beta-lactam antibiotics].
OBJECTIVE
To identify the role of Ph-SA in inhibiting beta-lactamase secretion of S. aureus and in enhancing the bactericidal activity of antibiotics against antibiotic resistant bacteria.


METHODS
To determine the effects of Ph-SA on beta-lactamase product of bacteria and on bactericidal activity of penicillin, the growth rate and lactamase activity of penicillin-resistant S. aureus cells in exponential growth were detected after treatment with 1.43 X 10(-4) micromol/mL (10 microg/mL) Ph-SA (Group 1), 2.81 x 10(-2) micromol/mL (10 microg/mL) penicillin (Group 2), 0.715 x 10(-4) micromol/mL(5 microg/mL) Ph-SA + 1.40 x 10(-2) micromol/mL (5 microg/mL) penicillin (Group 3) respectively; and a control group was detected for comparison. The same method was used to detect whether Ph-SA could enhance bactericidal activity of Cefazolin. Results It was revealed that 1.43 x 10(-4) micromol/mL (10 microg/mL) Ph-SA could inhibit beta-lactamase activity significantly, whereas no marked bactericidal activity was detected. The growth rate of bacteria cells treated with 0.715 x 10(-4) micromol/mL Ph-SA + 1.40 x 10(-2) mol/mL penicillin and that of bacteria cells treated with 0. 715 x 10(-4) micromol/mL (5 microg/mL) Ph-SA + 1.05 x 10(-2) micromol/mL (5 microg/mL) Cefazolin were the same as those treated by 2.81 x 10(-)2 micromol/mL (10 microg/mL)penicillin and 2.10 x 10(-2) micromol/mL (10 microg/mL) Cefazolin respectively, while the beta-lactamase activities of both groups were lower than control.


CONCLUSIONS
Ph-SA may be of value in enhancing the bactericidal activity of antibiotics and in alleviating the resistance of bacteria by inhibition of beta-lactamase activity.
Key Laboratory of Transplant Engineering and Immunology, the Ministry of Health, West China Hospital, Sichuan University, Chengdu 610041, China.
Xiao-yan
XY
Tang
Jie
J
Zhang
Li
L
Guo
Xiao-qing
XQ
Qiu
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D015310:Cefotiam / Q000494:pharmacology; D004357:Drug Synergism; D008826:Microbial Sensitivity Tests; D010675:Pheromones / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics; D001618:beta-Lactamases / Q000378:metabolism; D047090:beta-Lactams / Q000494:pharmacology*
C095698:Agr protein, Staphylococcus aureus; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D010675:Pheromones; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D047090:beta-Lactams; D015310:Cefotiam; D001618:beta-Lactamases