This study focuses on a new drug delivery system (Direct Antibiotic Delivery) to treat soft tissue infections. In this study, cefazolin is delivered directly to the target tissues using subcutaneous injection of antibiotic solution and then dispersed using high-frequency external ultrasound. Using this system, a much higher concentration of antibiotic can be achieved than through traditional treatment methods.

Unlike traditional delivery methods, Direct Antibiotic Delivery does not rely on blood supply and is beneficial for subjects with Diabetes or subjects who have received radiation therapy and blood supply is limited.

In this study, the DOSAGE of cefazolin that is delivered is a fraction of that which is already FDA approved for intramuscular (IM) administration. However, the CONCENTRATION in the target area is much higher than what can be achieved through intravenous (IV) administration, while still being far less than what is approved for IM administration.

Previous to this study, cefazolin was considered to be ineffective in treating Methicillin-resistant Staphylococcus aureus (MRSA) as it had only been tested at the concentrations that were attainable by traditional methods. Through our study and laboratory tests conducted at the Harford Hospital, Connecticut, we have confirmed that cefazolin can be effective against even the most resistant strains of MRSA if a high enough concentration is obtained.

Under this study, treatment is only available to subjects that have already undergone standard therapy, but were not able to resolve the infection.

Inclusion Criteria:

• Subjects with pathologically confirmed presence of serious or immediately life-threatening soft tissue infection, cellulitis or open wound caused by bacteria for which cefazolin at this concentration is likely to have activity to inhibit the bacteria, for example, Staphylococcus species or Streptococcus species, Escherichia coli, Proteus mirabilis.
• Wounds must demonstrate the presence of skin and skin structure infection, which may be demonstrated by one or more of the following: Culture results as aforementioned, swelling of the tissues, discoloration, open wounds, and/or drainage, which may or may not be associated with pain and/or tenderness.
• Confirmed presence of soft tissue cellulitis caused by bacteria for which cefazolin is likely to have activity to inhibit the bacteria will be evidenced by microbiologic cultures taken no greater than ten (10) days prior to treatment.
• Subject must have previously been treated by a qualified licensed physician using traditional surgical and/or medical treatments, which may include courses of IV antibiotics, but where Subject was unable to resolve their infection through traditional surgical and/or medical treatments for soft tissue cellulitis caused by bacteria for which cefazolin is likely to have activity to inhibit the bacteria at a maximum concentration of 1 gram per 100 ml saline, as demonstrated by the presence of induration, redness, open wounds, and/or soft tissue swelling.
• Subject must be referred by his or her treating physician to the Wound Care Center of the investigational hospital.
• The Wound Care Center of the investigational hospital has confirmed that standard therapies have failed to cure the subject's infection and the infection is still present.
• Subjects are not on concomitant antibacterial drugs since these drugs have failed to treat the subject's infection.
• Subject may be male or female and must be at least 18 years of age.
• Subject must sign informed consent as approved by the Institutional Review Board (IRB).

Exclusion Criteria:

• Subjects who have not received treatment by traditional surgical and/or medical therapies.
• Subjects who are allergic to cefazolin.
• Subjects who have a serious allergy to penicillin.
• Subjects with infections that involve body cavities.
• Subjects designated to be vulnerable, i.e., pregnant women, subjects under the age of 18, and subjects who need to have consent provided by a Legally Authorized Representative (LAR).
• Subjects who are unable or unwilling to comply with the protocol.
• Subjects who have a history of clinically significant or uncontrolled cardiac disease, including congestive heart failure, angina, myocardial infarction, arrhythmia, including New York Heart Association (NYHA) functional classification of 3.
• Subjects who have any other life-threatening illness or organ system dysfunction, which, in the opinion of the investigator, would either compromise subject safety or interfere with the evaluation of the safety of the test drug.
• Subjects who cannot understand English.
• Subjects who have received a treatment under this study are not eligible for re-admittance for thirty (30) days from the date of their last treatment.