Isolation and Host Range of Bacteriophage with Lytic Activity against Methicillin-Resistant Staphylococcus aureus and Potential Use as a Fomite Decontaminant.

Staphylococcus aureus (SA) is a commensal bacterium and opportunistic pathogen commonly associated with humans and is capable of causing serious disease and death including sepsis, pneumonia, and meningitis. Methicillin-resistant SA (MRSA) isolates are typically resistant to many available antibiotics with the common exception of vancomycin. The presence of vancomycin resistance in some SA isolates combined with the current heavy use of vancomycin to treat MRSA infections indicates that MRSA may achieve broad resistance to vancomycin in the near future. New MRSA treatments are clearly needed. Bacteriophages (phages) are viruses that infect bacteria, commonly resulting in death of the host bacterial cell. Phage therapy entails the use of phage to treat or prevent bacterial infections. In this study, 12 phages were isolated that can replicate in human SA and/or MRSA isolates as a potential way to control these infections. 5 phage were discovered through mitomycin C induction of prophage and 7 others as extracellular viruses. Primary SA strains were also isolated from environmental sources to be used as tools for phage discovery and isolation as well as to examine the target cell host range of the phage isolates by spot testing. Primary isolates were tested for susceptibility to oxacillin in order to determine which were MRSA. Experiments were performed to assess the host range and killing potential of newly discovered phage, and significant reductions in bacterial load were detected. We explored the utility of some phage to decontaminate fomites (glass and cloth) and found a significant reduction in colony forming units of MRSA following phage treatment, including tests of a phage cocktail against a cocktail of MRSA isolates. Our findings suggest that phage treatment can be used as an effective tool to decontaminate human MRSA from both hard surfaces and fabrics.

Relationship of in vitro synergy and treatment outcome with daptomycin plus rifampin in patients with invasive methicillin-resistant Staphylococcus aureus infections.

We report the findings of a study examining the relationship between in vitro daptomycin-rifampin synergy and the therapeutic outcome of 12 patients with complex deep methicillin-resistant Staphylococcus aureus (MRSA) infections treated for prolonged periods with this combination. Checkerboard synergy was found in nine cases and was 100% predictive of therapeutic success; absence of synergy was found in three cases, two of which were therapeutic failures (P = 0.045). No relationship was observed between synergy and outcome by time-kill assessment. Checkerboard synergy may predict clinical response to daptomycin plus rifampin for complex invasive MRSA infections requiring prolonged treatment.

Stress ulcer prophylaxis: reducing non-indicated prescribing after hospital discharge.

BACKGROUND: Gastric acid suppressant medications used as stress ulcer prophylaxis (SUP) in the intensive care unit (ICU) are often prescribed inappropriately after discharge. We present tools to reduce the use and cost of non-indicated SUP. OBJECTIVE: To reduce the non-indicated use of SUP after hospital discharge originally started in the ICU, using an education intervention and pharmacist-led medication reconciliation on patient care rounds and at hospital discharge. METHODS: In a retrospective medical record review using a historic control, 356 consecutively admitted patients to the medical/surgical ICU at the University of Wisconsin Hospital were assessed for the appropriate use of SUP at admission to the ICU, at transfer to a general care unit, and at hospital discharge. The education intervention involved teaching both the medical and pharmacist staff about indications for SUP using a memorandum and a pocket guide. Pharmacists also conducted medication reconciliation during daily patient care rounds and at discharge to justify medication use. The outcome of this study is the percentage of patients prescribed non-indicated gastric acid suppressants at hospital discharge. This outcome is compared to a previous study conducted at our hospital. RESULTS: Of 356 eligible patients, 308 (86.5%) received SUP while in the ICU. Thirty-nine (11%) were given continuing SUP after discharge from the hospital, of which 31 (8.7%) had no clear indication. This was a 64.3% reduction from the 24.4% found in the prior study (p < 0.0001). CONCLUSIONS: Educational materials that guide prescribing, pharmacist interaction on patient care rounds, and pharmacist-conducted medication reconciliation significantly reduced the prescribing of non-indicated gastric acid suppressant medications after hospital discharge.