Objective: A multiagency investigation was initiated to determine the extent of the outbreak, assess risk factors, and implement control measures.
Methods: Patient and procedure data were collected for all injections occurring April 27–May 13, 2009. Information from follow-up exams, patient interviews, and medical chart reviews were used to determine patients’ case status. A case was defined as laboratory-confirmed infection in a clinic patient or clinical evidence of infection ≤14 days after a clinic patient received an injection. In addition, mock injection procedures were observed; two available case isolates and seven employee nasal swabs were collected. Isolates determined to be MSSA by morphology and standard biochemical tests were further characterized by using pulsed-field gel electrophoresis (PFGE).
Results: During April 27–May 13, 2009, a total of 111 injection procedures were performed on 110 patients. Of eight cases identified, 63% were female; median age was 65 years. Average time between injection and illness onset was 3.5 days. Seven hospitalizations (median duration: 11 days) occurred for diagnoses of meningitis (1), epidural abscess (3), and bacteremia (4). All eight cases received lumbar epidural injections performed by the same clinician (clinician X) during May 4–6, 2009; the attack rate among epidural injections performed by clinician X on these dates was 30%. The following breaches in infection control were identified during mock procedures: masks were not regularly worn during procedures; patient skin preparation was below standard; and syringes used to administer medication through epidural needles were routinely reused to access multiuse medication vials. These breaches prompted patient notifications recommending testing for BBPs. A nasal swab from clinician X yielded an MSSA USA600 isolate that was indistinguishable by PFGE from the two available case isolates.
Conclusions: Identified infection control breaches likely contributed to this cluster of MSSA infections. On the basis of recommendations resulting from the investigation, pain clinic staff were retrained and procedures were revised. Results of patient notifications and testing are pending. Clinician education on adherence to Standard Precautions and injection safety is essential in minimizing disease transmission in nonhospital healthcare settings.