1,5-Anhydro-D-fructose: A natural antibiotic that inhibits the growth of gram-positive bacteria and microbial biofilm formation to prevent nosocomial infection

Abstract

Nosocomial infections caused by microbial opportunistic infections or microbial biofilms may occur during hospitalization and increase patient morbidity, mortality and health care costs. Artificial antibiotic agents were initially used to prevent infection; however, the high prevalence of nosocomial infections has resulted in their excessive use, which has led to microbial resistance to these agents. The increase in microbial resistance to antibiotics and the development of antibiotic agents may be the cause of the production of other microbial resistance. Thus, natural compounds that have no adverse side effects would be a preferred treatment modality. Recently, the monosaccharide 1,5-anhydro-D-fructose (1,5-AF), a natural plant compound derived from starch, has been found to have multifunctional properties, including antioxidant, antiplatelet aggregation by thrombin and anti-inflammatory activities. The results of the present study demonstrate that 1,5-AF suppressed the growth of coagulase-negative staphylococci on the hands as well as the growth of Staphylococcus epidermidis, which is a cause of opportunistic infections. Furthermore, 1,5-AF suppressed biofilm formation by the methicillin-resistant Staphylococcus aureus. In conclusion, 1,5-AF is a natural compound that may be effective in preventing nosocomial infections, without causing adverse side effects.

Figure 1.

Growth inhibition of coagulase-negative staphylococci (CNS) on hands by 1,5-AF. Each hand was spread with 75% ethanol with or without the addition of 1% of 1,5-AF for 1 min, and then placed on agar plates. The specimens were incubated at 37°C for 24 h. CONT, control; 1,5AF, 1,5-anhydro-D-fructose.

Figure 2.

Growth inhibition of S. epidermidis by 1,5-AF. (A) Detection of S. epidermidis. All the keys on keyboards at our clinical laboratory were swabbed with sterile cotton swabs, and the specimens were incubated at 37°C for 24 h. (B) Effect of 1% AF on S. epidermidis. S. epidermidis suspension from (A) was spread on 5% sheep blood agar, 5% sheep blood agar and 75% ethanol (left), or 5% sheep blood agar and 1% AF + 75% ethanol (right), and incubated for 16 h. CONT, control; 1,5AF, 1,5-anhydro-D-fructose.

Figure 3.

Inhibition of biofilm formation of methicillin-resistant Staphylococcus aureus (MRSA) by 1,5-AF. (A) Inhibition of MRSA biofilm by 1,5-AF. Cultured MRSA was incubated for 0.5–18 h in a 96-microplate and then removed by washing with PBS. The plates were stained with 0.1% crystal violet for biofilm production. (B) Measurement of MRSA growth with or without 1,5-AF. Cultured MRSA was incubated for 18 h, then cell growth was measured at 600 nm. CONT, control; 1,5AF, 1,5-anhydro-D-fructose.