Preparing Flush Syringes from a Common-Source Bag of Saline Leads to Infection Outbreak

Tsukamurella is a gram positive bacilli that have been isolated from soil and sludge and do not usually cause human disease.  Over 600,000 oncology patients receive chemotherapy in outpatient clinics in the United States annually. Many of these patients have central venous access devices and coupled with the immunosuppressive chemotherapies these factors place these patients at particularly high risk of blood stream infections.

A local acute care hospital noticed an unusual increase of blood cultures positive for gram positive bacilli, all identified as Bacillus species and all coming from patients treated at a local oncology clinic.  The outbreak was reported to the West Virginia Bureau of Public Health (WVBPH) which performed an onsite investigation at the clinic.  The Centers for Disease Control later confirmed the cultured bacillus isolates to be that of the Tsukamurella species.

All patients testing positive for Tsukamurella had underlying malignancy and indwelling central lines; the median age of the patients was 68 years and 47% were male. After the oncology clinic staff were interviewed and infection control practices were assessed it was determined that the likely source of the infection was the practice of drawing saline flush syringes from a common bag of saline. Notably one of the case patients central line was accessed only once by the clinic staff to flush the line with saline. Six days later the patient presented to the emergency department with neutropenia, fever, chills, hypotension and blood cultures positive for Tsukamurella species.  Two additional cases had implanted ports that were only accessed for monthly flushes with saline by the clinic.

During the WVBPH site visit several lapses in infection control practices were noted pertaining to the preparation of chemotherapy and non-chemotherapy medications within the medication prep room of the outpatient clinic. For example single dose medication vials opened outside of the hood were stored and reused over multiple days.  Most non chemotherapy medications were prepared need a sink, which could contaminate medications with tap water. Occasionally staff drew and combined multiple medications using a single syringe and needle, which could cross contaminate medication vials being used for other patients if aseptic technique was not strictly followed.  The chemotherapy prep hood was located near a window that was occasionally opened, violating strict airflow requirement guidelines for safely preparing sterile medications.  When medications were prepared under the hood gloves were not regularly disinfected during use by routine application of isopropyl alcohol to gloved hands.  Insects had been seen on the gloves that were stored on the windowsill.  Chemo hood disinfection protocols were not followed appropriately using paper towels with the potential to shed fibers leading to possible contamination and using alcohol of insufficient strength (47.5%) to clean the hood.

After the site visit, as recommended by the WVBPH, the clinic stopped preparing its own saline flushes, began using prepackaged saline flushes. Staff stopped using non- sterile cotton balls and alcohol for antisepsis and implemented the use of sterile 70% isopropyl alcohol pads to disinfect all catheter connection caps and medication vials.

This outbreak demonstrates that improper infection control practices can result in blood stream infections. Saline bags are not labeled as FDA approved multiple dose containers. Using a preservative free bag of saline to prepare multiple pre-drawn saline flush syringes increases the chance of contaminating the flush and common saline bag, especially when not performed under the optimal condition of a properly operating and maintained hood.  This practice has been implicated in previous outbreaks of bacterial bloodstream infections.   Practice Criteria suggested by the Infusion Nurses Society state that single use systems including single dose vials and prefilled syringes are the preferred choices for flushing and locking of catheters. If multiple dose containers must be used each container should be dedicated to a single patient. 

To read the entire SHEA Journal article;  Outbreak of Tsukamurella Species Bloodstream Infection among
Patients at an Oncology Clinic, West Virginia, 2011–2012 click the title link.