Bactericidal activity of citrate against Gram-positive cocci

AIMS: Coagulase-negative staphylococci (CNS) are now important nosocomial pathogens and are usually resistant to multiple antibiotics. Citrate is an alternative antimicrobial product which has been used as a preservative. METHODS AND RESULTS: In this pilot study the bactericidal activity of Na citrate against 10 isolates of CNS and 6 other gram-positive pathogens was examined and compared with that of Na lactate. CONCLUSIONS: All staphylococci tested were susceptible (> or = 2 log(10) killing) to citrate at 6.25-25 mg ml(-1). Na lactate showed only modest killing at 50 or 100 mg ml(-1). SIGNIFICANCE AND IMPACT OF THE STUDY: Citrate may warrant broader evaluation as an antimicrobial additive such as in topical agents.