Efficacy of nucleoside-nucleotide mixture against methicillin-resistant Staphylococcus aureus infection in mice treated with cyclophosphamide

Abstract

The effects of nucleoside-nucleotide mixture (NNM) and granulocyte-colony stimulating factor (G-CSF) on response to methicillin-resistant Staphylococcus aureus (MRSA) challenge in cyclophosphamide (CPA) treated mice were studied. Thirty BALB/c mice were randomly divided into 3 groups of 10 animals each and fed 20% nucleotide-free casein diet. On the 10th day on the diet, mice were intraperitoneally administered CPA and 4 hr later, inoculated intravenously with viable MRSA organisms. The mice were intraperitoneally administered saline (control group) or NNM daily from the onset of the experiment or injected G-CSF for 4 consecutive days beginning on the day after CPA injection. The cumulative percentage of survival over 10 days in the control group was 20% as compared to 60% and 80% in the NNM and G-CSF groups, respectively. Of the surviving mice, in the NNM group about half eliminated the MRSA organisms in spleen and kidney, as compared to none in the control and G-CSF groups. Our results suggest that administration of NNM as well as G-CSF may be used to an advantage to enhance the host resistance in CPA treated septic mice; and that NNM alone or in combination with other nutrients or pharmacologic agents may prove to be of clinical importance in the protection of immunocompromised patients against opportunistic pathogens.