Outbreak of Serratia marcescens bloodstream and central nervous system infections after interventional pain management procedures

Is there a widespread clone of Serratia marcescens producing outbreaks worldwide?

BACKGROUND

Serratia marcescens frequently causes outbreaks in healthcare settings. There are few studies using high-throughput sequencing (HTS) that analyse S. marcescens outbreaks. We present the analysis of two outbreaks in neonatal intensive care units (NICUs) in hospitals from the Comunitat Valenciana (CV, Spain) and the impact of using different reference genomes.

METHODS

DNA from cultured isolates was extracted and sequenced by HTS using Illumina NextSeq. Reads were mapped against two reference genomes, strains UMH9 and Db11, and the unmapped fraction of the genomes was assembled to fully genetically characterize the isolates.

FINDINGS

Isolates from the first outbreak were identical to the UMH9 reference, an unrelated isolate obtained three years earlier in the USA. This did not occur when the Db11 strain, a standard reference for S. marcescens, was used as the reference for mapping. To check whether UMH9 was a widely distributed clone spreading in the CV, the second outbreak isolates were mapped against this reference. They were not closely related to this strain, and this outbreak could be defined as such regardless of the reference used for mapping the reads.

CONCLUSIONS

The choice of the reference for genomic analysis of outbreaks is a critical decision. In the case of the first outbreak, this choice changed the interpretation of the results drastically, allowing or preventing the definition of the outbreak according to the reference used. Although HTS is a powerful tool for epidemiological analysis, it is still essential to collect microbiological and epidemiological data for the correct interpretation of the results.

Proactive Risk Assessment of Surgical Site Infections in Ambulatory Surgery Centers

BACKGROUND

The Socio-Technical Probabilistic Risk Assessment, a proactive risk assessment tool imported from high-risk industries, was used to identify risks for surgical site infections (SSIs) associated with the ambulatory surgery center setting and to guide improvement efforts.

OBJECTIVES

This study had 2 primary objectives: (1) to identify the critical risk factors associated with SSIs resulting from procedures performed at ambulatory surgery centers and (2) to design an intervention to mitigate the probability of SSI for the highest risk factors identified.

METHODS

Inputs included quantitative and qualitative data sources from the evidence-based literature and from health care providers. The Socio-Technical Probabilistic Risk Assessment ranked the failure points (events) on the basis of their contribution to an SSI. The event, entitled "Failure to protect the patient effectively," which included several failure points, was the most critical unique event with the highest contribution to SSI risk.

RESULTS

A total of 51.87% of SSIs in this setting were caused by this failure. Consequently, we proposed an intervention aimed at all 5 major components of this failure.

CONCLUSIONS

The intervention targets improvements in skin preparation; proper administration of antibiotics; staff training in infection control principles, including practices for the prevention of glove punctures; and procedures to ensure the removal of watches, jewelry, and artificial nails.

Using medical student observers of infection prevention, hand hygiene, and injection safety in outpatient settings: A cross-sectional survey

BACKGROUND

Health care-associated infection outbreaks have occurred in outpatient settings due to lapses in infection prevention. However, little is known about the overall infection prevention status in outpatient environments.

METHODS

A cross-sectional design was employed to assess infection prevention policies and practices at 15 outpatient sites across New Mexico in 2014 during a medical student outpatient rotation. A standardized infection prevention checklist was completed via staff interview; observations of injection safety practices and hand hygiene behavior were conducted. Aggregate data were analyzed using Excel (Microsoft, Redmond, WA) and Stata (version 12.1, Stata Corp, College Station, TX) statistical software.

RESULTS

Medical practice staff interviews reported a mean of 92.8% (median, 96.7%; range, 75.0%-98.9%) presence of recommended policies and practices. One hundred sixty-three injection safety observations were performed that revealed medication vial rubber septums were disinfected with alcohol 78.4% (95% confidence interval [CI], 71.1%-84.7%) of the time before piercing. Three hundred thirty hand hygiene observations revealed 33.9% (95% CI, 28.8%-39.1%) use of alcohol-based handrub, 29.1% (95% CI, 24.2%-34.0%) use of soap and water, and 37.0% (95% CI, 31.8%-42.4%) use of no hand hygiene.

DISCUSSION AND CONCLUSION

These findings support the need for ongoing infection prevention quality improvement initiatives in outpatient settings and underscore the importance of assessing both self-report and observed behavior of infection prevention compliance.

Exserohilum infections associated with contaminated steroid injections: a clinicopathologic review of 40 cases

September 2012 marked the beginning of the largest reported outbreak of infections associated with epidural and intra-articular injections. Contamination of methylprednisolone acetate with the black mold, Exserohilum rostratum, was the primary cause of the outbreak, with >13,000 persons exposed to the potentially contaminated drug, 741 confirmed drug-related infections, and 55 deaths. Fatal meningitis and localized epidural, paraspinal, and peripheral joint infections occurred. Tissues from 40 laboratory-confirmed cases representing these various clinical entities were evaluated by histopathological analysis, special stains, and IHC to characterize the pathological features and investigate the pathogenesis of infection, and to evaluate methods for detection of Exserohilum in formalin-fixed, paraffin-embedded (FFPE) tissues. Fatal cases had necrosuppurative to granulomatous meningitis and vasculitis, with thrombi and abundant angioinvasive fungi, with extensive involvement of the basilar arterial circulation of the brain. IHC was a highly sensitive method for detection of fungus in FFPE tissues, demonstrating both hyphal forms and granular fungal antigens, and PCR identified Exserohilum in FFPE and fresh tissues. Our findings suggest a pathogenesis for meningitis involving fungal penetration into the cerebrospinal fluid at the injection site, with transport through cerebrospinal fluid to the basal cisterns and subsequent invasion of the basilar arteries. Further studies are needed to characterize Exserohilum and investigate the potential effects of underlying host factors and steroid administration on the pathogenesis of infection.

Public perceptions and preferences for patient notification after an unsafe injection

BACKGROUND

Unsafe injection practices in health-care settings often result in notification of potentially affected patients, to disclose the error and recommend blood-borne pathogens testing. Few studies have assessed public perceptions and preferences for patient notification.

METHODS

Six focus groups were conducted during Fall 2009, with residents of Atlanta, GA, and New York City, NY. Questions focused on preferences for receiving health information, knowledge of safe injection practices, and responses to and preferences for a patient notification letter. A mixed-method analysis was performed for qualitative themes and descriptive statistics.

RESULTS

A total of 53 individuals participated; only 2 had ever heard of the term safe injection practices. After identification of unsafe injection practices, participants preferred to be notified via telephone, letter/mailing, email, or face-to-face from the facility where the incident occurred. More than 25 different types of information were mentioned as elements to be placed in a patient notification letter including: corrective actions by the facility, course of action for the patient, assurance of medical coverage, and how it happened/reason for the incident. Participants preferred that the tone of the letter be empathetic; nearly all indicated it was "very likely" that they would seek testing if notified.

CONCLUSIONS

Facilities and health departments should strive to assure the notification process is conducted swiftly, clearly guiding affected patients to the necessary course of action. Notification letters are not "one size fits all," and some preferences expressed by patients may not be feasible in all situations. Prevention efforts should be complemented by research on improving effective patient communications when unsafe injection practices necessitate patient notification.

Outbreak of bacterial meningitis among patients undergoing myelography at an outpatient radiology clinic

PURPOSE

To investigate an outbreak of bacterial meningitis at an outpatient radiology clinic (clinic A) and to determine the source and implement measures to prevent additional infections.

METHODS

A case was defined as bacterial meningitis in a patient undergoing myelography at clinic A from October 11 to 25, 2010. Patients who underwent myelography and other procedures at clinic A during that period were interviewed, medical records were reviewed, and infection prevention practices were assessed. Case-patient cerebrospinal fluid (CSF) specimens, oral specimens from health care personnel (HCP), and opened iohexol vials were tested for bacteria. Bacterial isolates were compared using pulsed-field gel electrophoresis. A culture-negative CSF specimen was tested using a real-time polymerase chain reaction assay.

RESULTS

Three cases were identified among 35 clinic A patients who underwent procedures from October 11 to 25, 2010. All case-patients required hospitalization, 2 in an intensive care unit. Case-patients had myelography performed by the same radiology physician assistant and technician on October 25; all patients who underwent myelography on October 25 were affected. HCP did not wear facemasks and reused single-dose iohexol vials for multiple patients. Streptococcus salivarius (a bacteria commonly found in oral flora) was detected in the CSF of 2 case-patients (1 by culture, 1 using real-time polymerase chain reaction) and in HCP oral specimens; 1 opened iohexol vial contained Staphylococcus epidermidis. Pulsed-field gel electrophoresis profiles from the case-patient S salivarius and the radiology physician assistant were indistinguishable.

CONCLUSIONS

Bacterial meningitis likely occurred because HCP performing myelography did not wear facemasks; lapses in injection practices may have contributed to transmission. Targeted education regarding mask use and safe injection practices is needed among radiology HCP.

Serratia infections: from military experiments to current practice

Serratia species, in particular Serratia marcescens, are significant human pathogens. S. marcescens has a long and interesting taxonomic, medical experimentation, military experimentation, and human clinical infection history. The organisms in this genus, particularly S. marcescens, were long thought to be nonpathogenic. Because S. marcescens was thought to be a nonpathogen and is usually red pigmented, the U.S. military conducted experiments that attempted to ascertain the spread of this organism released over large areas. In the process, members of both the public and the military were exposed to S. marcescens, and this was uncovered by the press in the 1970s, leading to U.S. congressional hearings. S. marcescens was found to be a certain human pathogen by the mid-1960s. S. marcescens and S. liquefaciens have been isolated as causative agents of numerous outbreaks and opportunistic infections, and the association of these organisms with point sources such as medical devices and various solutions given to hospitalized patients is striking. Serratia species appear to be common environmental organisms, and this helps to explain the large number of nosocomial infections due to these bacteria. Since many nosocomial infections are caused by multiply antibiotic-resistant strains of S. marcescens, this increases the danger to hospitalized patients, and hospital personnel should be vigilant in preventing nosocomial outbreaks due to this organism. S. marcescens, and probably other species in the genus, carries several antibiotic resistance determinants and is also capable of acquiring resistance genes. S. marcescens and S. liquefaciens are usually identified well in the clinical laboratory, but the other species are rare enough that laboratory technologists may not recognize them. 16S rRNA gene sequencing may enable better identification of some of the less common Serratia species.

Severe methicillin-susceptible Staphylococcus aureus infections associated with epidural injections at an outpatient pain clinic

BACKGROUND

Recent outbreaks in ambulatory care settings have highlighted infection control breaches as risk factors for disease transmission. In May 2009, 3 patients were hospitalized with severe methicillin-susceptible Staphylococcus aureus (MSSA) infections after receiving epidural injections at a West Virginia outpatient pain clinic.

METHODS

We conducted a retrospective cohort study evaluating clinic patients who received injections during a 3-week period. A case was defined as laboratory-confirmed infection or clinical evidence of infection ≤ 14 days after a patient received an injection. Infection control procedures were assessed. MSSA isolates from patient infections and clinic staff nasal swabs were genotyped by using pulsed-field gel electrophoresis.

RESULTS

Eight (7%) of 110 cohort patients met the case definition; 6 (75%) cases were laboratory confirmed. Eight (12%) of 69 patients who received epidural injections were case patients compared with none of the other 41 patients (P = .02). During procedures, staff use of face masks and preparation of patient skin were suboptimal; epidural injection syringes were reused to access shared medication vials. MSSA isolates from 2 patients and 1 staff member were indistinguishable by pulsed-field gel electrophoresis.

CONCLUSION

Infection control breaches likely facilitated MSSA transmission to patients receiving epidural injections. Adhering to correct infection control practices in ambulatory care settings is critical to prevent disease transmission.