Antimicrobial stewardship and infection control: December 2018

A comprehensive UTI bundle dramatically improved management of ASB and symptomatic UTI at a single Canadian hospital.  The authors performed a before-after study to assess their impact of their UTI management bundle on UTI treatment and outcomes at their hospital.  The intervention consisted of three major components.  First, nurses and prescribers were educated about appropriate indications for urine culture, criteria for UTI diagnosis, and guidelines-based UTI treatment, with an emphasis on not sending urine cultures without an MD/APP’s order.  Second, laboratory reporting procedure was changed so that unless clinicians had specifically documented concern for UTI, pyelonephritis, or urosepsis, all positive cultures would be reported out with the message “The majority of positive urine cultures in inpatients represent asymptomatic bacteriuria. Please call Microbiology laboratory at XXX-XXXX if your patient is symptomatic and you require microbial identification and susceptibility results.”  Finally, pharmacists provided prospective audit and feedback of positive urine cultures for inpatients according to the institution’s guideline.

The authors set out to examine ~300 consecutive urine samples before and after the intervention.  After exclusion criteria were applied, a total 276 cases in the pre-intervention period and 268 cases in the post-intervention period were included in the study.  Patients in the postintervention period were less frequently admitted to a surgical service (75% vs 87%), had less asymptomatic bacteriuria (ASB; 50% vs 60%), and had more foley catheters (39% vs 24%) than patients in the preintervention period; otherwise the groups were similar.  As a result of the educational intervention, urine cultures obtained without a prescriber’s order dropped from 28% to 7%.  As a result of the laboratory reporting change, 58% of the urine culture results were reported out with the statement above rather than speciation and sensitivities, and of those in only 44% were speciation and susceptibilities requested. The incidence of antimicrobial therapy dropped accordingly (58% vs 79% in the preintervention period), and specifically the rate of inappropriate therapy of ASB dropped from 67% to 17%.  Overall adherence to UTI management best practices increased from 12% to 38%, and the number of avoidable antibiotic days administered dropped from 781 to 138.  Pharmacists were able to review 28% of the urine cultures in the postintervention period; the pharmacists had a recommendation to modify therapy in 71% of cases, and 87% of those recommendations were accepted by the MD/APP.  Finally, there were no statistically significant differences in the rates of untreated UTI, sepsis, or C.difficile infection in the post-intervention period.

To me the most interesting part of this study was the change in laboratory reporting of urine cultures:  for the low low price of nothing, the lab was able to dramatically reduce the rate of antimicrobial therapy for asymptomatic bacteriuria.  Just goes to show that diagnostic test stewardship and antimicrobial stewardship go hand in hand. 30501661

This paper describes a large and difficult to control outbreak of KPC-type carbapenem-resistant E. coli involving hospital ward sinks.   This outbreak took place at a hospital in Manchester (UK).  The outbreak was first detected in 2015, after a cluster of six patients colonized with CRE E. coli were identified.  The initial intervention consisted of reinforcing standard infection control procedures and closing two affected hospital wards for decontamination with bleach terminal cleaning followed by fumigation with hydrogen peroxide.  The wards were opened one and three weeks later, respectively.  The hospital had begun a CRE rectal screening program, which identified colonization in about 4% of patients; these patients were subsequently cohorted together on a single ward.

Despite the enhanced infection prevention and control measures, the outbreak continued over the following months, leading to repeated closures of both of the affected wards for environmental decontamination, all of which did nothing to arrest the course of the outbreak.  Between February and September 2015, 88 patient colonizations with KPC-E.coli were detected and two patients developed clinical infections (one UTI and one sternal wound infection, successfully treated with gentamicin and ciprofloxacin, respectively).  At this point the infection control team began environmental culturing of the wards to search for a reservoir of the bacteria, with 333 samples taken from two wards implicated in the outbreak.  The samples included sinks, drains, showers, toilets, keyboards, door hands, sponges, etc – every high-touch surface the team could find.  They found 85 samples positive for CRE, which included shower drains, sink taps, drains, strainers, trap water, toilet bowls, and a few other sites – all involving the hospital’s plumbing and wastewater systems.

The infection control team first acted on this information by replacing the traps of colonized sinks and performing pipework cleaning with a brush to try and remove biofilm. However, after the outbreak persisted, the affected wards were closed once again, this time for a complete overhaul of all plumbing back to the central drainage system.  New sink plugholes designed to prevent water aerosolization and biofilm formation were installed.  After these interventions, the incidence of CRE colonization intially fell by about 90%; however, recolonization of the sink and wastewater sites with CRE recurred rapidly, and CRE colonizations resumed thereafter, albeit at a lower incidence.  The total cost of the disruption to the hospital’s operation and the subsequent renovations exceeded 5 million euros.

I’ve skipped over a lot of this paper that will be of interest to serious epidemiologists and infection control gurus (i.e. the diversity and sequencing/phylogeny of the bacteria implicated in the outbreak); while that’s all a bit over my head, I do think this paper does a good job illustrating how a hospital infection control team goes about tracking down an outbreak and planning interventions to mitigate it, as well as the difficulties that accompany those efforts.  I’m also left wondering if some sort of biologically-based intervention might have been helpful - e.g., trying to colonize the plumbing with nonpathogenic E.coli & other bacteria, sort of like an FMT for the plumbing. 

Or maybe that’s just a pipe dream.  30249685