ASP Scan (Weekly) for Dec 07, 2018

Costco antibiotic policy
Severe MRSA in China, Australia
Antibiotic cycling and MRSA, C diff incidence
Antibiotic time-outs
Resistant gonorrhea in Europe
Procalcitonin-guided antibiotic therapy
'Expected practice' and short-course antibiotics
UTI management bundle

Costco commits to responsible antibiotic use in meat, poultry supply chain

Costco today updated its animal welfare standards to include a policy on the responsible use of antibiotics in its meat and poultry supply chains, according to shareholder advocacy group As You Sow.

The policy commits Costco to limiting the application of medically important antibiotics to therapeutic use for the prevention, control, and treatment of disease, but not for growth promotion or feed efficiency, and only under the supervision of a licensed veterinarian. The company says it will set a target for compliance with this policy on or before December 2020.

While the policy does not commit Costco to eliminating the routine use of medically important antibiotics for disease prevention among supplier farms, it does say the company will assess the feasibility of doing so on or before December 2020.

On Sep 29, As You Sow filed a shareholder proposal that requested Costco develop an enterprise-wide policy to phase out the use of medically important antibiotics in its meat and poultry, with the exception of treatment and non-routine control of diagnosed illnesses.

"We are particularly encouraged by the company's plans to create mechanisms through which they will be able to verify supplier compliance with their antibiotics policy," Christy Spees, environmental health program manager at As You Sow, said in a press release. "This is a significant undertaking, and one that we hope will cause a ripple of change in the meat industry and set a standard for other retail chains."
Dec 7 As You Sow press release
December 2018 Costco animal welfare standards


Severe MRSA ST398 infections reported in China, Australia

Originally published by CIDRAP News Dec 5

Two articles yesterday in Emerging Infectious Diseases describe severe infections caused by highly virulent strains of methicillin-resistant Staphylococcus aureus (MRSA) sequence type (ST) 398, a clonal type that is usually associated with animals.

In one article, Chinese researchers report on two MRSA ST398 strains isolated from two patients with severe surgical site infections. Antimicrobial susceptibility testing showed that both strains were resistant to beta-lactam antibiotics but were susceptible to most other antibiotics. Whole-genome sequencing  (WGS) showed the isolates had similar resistance genes (blaZ and mecA) and virulence factors, but did not harbor the tetM tetracycline-resistance gene, which is typically found in livestock-associated (LA) MRSA.

The patients denied any livestock contact, and further genetic analysis showed characteristics of community-associated (CA) MRSA isolates. When tested in a mouse infection model, the strains caused abscesses that were significantly larger than those caused by other CA-MRSA strains previously isolated from patients in China and South Korea.

In the second article, Australian scientists report on a MRSA ST398 isolated from a patient with MRSA bacteremia. Antimicrobial susceptibility testing showed that the isolate was only resistant to beta-lactams, and WGS revealed the presence of the blaZ and mecA resistance genes and several virulence factors, but not the tetM gene.

Phylogenetic analysis indicated the strain had a much closer relationship to CA-MRSA ST398 isolates previously described in China than to LA-MRSA ST398 isolates that have been frequently identified in pigs in Australia. The scientists were not able to establish whether the patient—who was from Singapore but working in Australia—had contact with livestock or had visited China before his illness.

"Unlike LA-MRSA ST398, CA-MRSA ST398 has been shown to be highly virulent and has become the predominant CA-MRSA circulating in Shanghai, China," the authors of the study write. "Thus, continued monitoring of this strain's epidemiology and preventing its widespread transmission is essential.

LA-MRSA ST398 was first identified in pigs and pig farmers in 2003 and is the predominant lineage of LA-MRSA in Europe and North America. To date, most human infections have been found in people with direct animal contact.
Dec 4 Emerg Infect Dis article #1
Dec 4 Emerg Infect Dis article #2


Study finds antibiotic cycling not tied to lower C diff, MRSA incidence

Originally published by CIDRAP News Dec 5

In another study yesterday in Emerging Infectious Diseases, researchers in Northern Ireland reported that an antibiotic cycling strategy implemented at a teaching hospital did not lead to a reduced incidence of healthcare-associated Clostridioides difficile (HA-CDI) or healthcare-associated (HA) MRSA.

The intervention at Antrim Area Hospital involved cyclical restrictions of amoxicillin-clavulanic acid, piperacillin-tazobactam, and clarithromycin over a 2-year period (October 2013 to September 2015). The intervention was based on an analysis of epidemiologic data from 2007 through 2012 that identified macrolides and piperacillin-tazobactam as significantly associated with HA-MRSA and amoxicillin-clavulanic acid as significantly associated with HA-CDI. The policy restricted use of piperacillin-tazobactam and macrolides on alternate months and amoxicillin-clavulanic acid for 2 consecutive months every 4 months.

To determine whether the strategy had an impact on HA-MRSA and HA-CDI incidence and new extended-spectrum beta-lactamase (ESBL) incidence and resistance, the researchers used segmented regression analysis to compare outcome measures before and after introduction of the policy and between the intervention hospital and a control hospital. They also looked at whether any effect observed during the intervention was reversed upon return to standard policy.

The results showed that during the intervention, HA-CDI incidence did not change and HA-MRSA increased significantly at the intervention hospital, while resistance of new ESBL isolates to amoxicillin-clavulanic acid and piperacillin-tazobactam decreased significantly. But after the hospital returned to its standard antibiotic policy, incidence of HA-MRSA decreased, incidence of new ESBLs increased, and ESBL resistance to piperacillin-tazobactam increased.

The authors conclude, "Our results suggest that antibiotic cycling is not an appropriate strategy to reduce the incidence of HA-MRSA or HA-CDI but might be effective in reducing ESBLs." 
Dec 4 Emerg Infect Dis study


Study: Antibiotic 'time-out' strategy doesn't reduce overall use

Originally published by CIDRAP News Dec 5

A multicenter study yesterday in Clinical Infectious Diseases found that a provider-drive antibiotic "time-out" (ATO) did not have an impact on overall antibiotic use but was associated with a decrease in inappropriate therapy.

The ATO strategy, which involves structured conversations during clinical rounds to determine if modification or discontinuation of antibiotic therapy is warranted, was implemented across 11 units located in six hospitals in Maryland. The ATO took place on antibiotic days 3 to 5, and patients receiving any of 23 selected study antibiotics for at least 3 calendar days were eligible.

In the quasi-experimental study, researchers compared hospital antibiotic days of therapy (DOT) per patient admission and total antibiotic DOT per admission during a 6-month baseline period and a 9-month intervention period. They also evaluated the appropriateness of antibiotic therapy on days 3 to 5.

Among the study population, the average hospital DOT was 12.7 per admission and total DOT was 18.9 per admission in the baseline period and 12.2 and 18.2, respectively, in the intervention period. After controlling for study unit and season, there was no difference between hospital DOT or total DOT per admission in the baseline versus intervention period. However, modification in the antibiotic prescription was more common, and there was a decrease in inappropriate antibiotic therapy on days 3 to 5, in the intervention period (45% in the baseline vs. 31% in the intervention).

"We believe that the results of our study contribute to existing evidence supporting the need for ASPs [antibiotic stewardship programs] to achieve goals of optimizing prescriptions and reducing overall antibiotic use," the authors of the study write. "The ATO may be a useful adjunct, but not a replacement for other stewardship interventions." 
Dec 4 Clinical Infect Dis study


Gonorrhea in Europe becoming less susceptible to ceftriaxone

Originally published by CIDRAP News Dec 4

Annual sentinel surveillance of Neisseria gonorrhea isolates in 25 European countries has found decreasing susceptibility to ceftriaxone, according to a study yesterday in BMC Infectious Diseases.

The analysis of 2,660 N gonorrhea isolates collected in 2016 by the European Gonococcal Antimicrobial Surveillance Program found no isolates that were resistant to ceftriaxone, but 14 isolates had a ceftriaxone minimum inhibitory concentration (MIC) of 0.125 milligrams per liter (mg/L), which is the resistance breakpoint. One of these isolates was also resistant to azithromycin. In addition, the proportion of isolates with decreased susceptibility to ceftriaxone (MICs from 0.032 mg/L to 0.125 mg/L) increased from 15% in 2015 to 17.7% in 2016.

Azithromycin resistance remained stable, with a resistance rate of 7.5% in 2016 compared with 7.1% in 2015. But seven isolates (0.3%) from five countries displayed high-level azithromycin resistance, up from five in 2015. Cefixime resistance was detected in 2.1% of isolates in 2016 compared with 1.7% in 2015, and ciprofloxacin resistance remained stable at 46.5% (compared with 49.4% in 2015).

The authors of the study—a team of researchers from Public Health England, the European Centre for Disease Prevention and Control, and the World Health Organization—say the decreasing ceftriaxone susceptibility and relatively high azithromycin resistance are a major concern, since European guidelines recommend ceftriaxone plus azithromycin as the first-line therapy for gonorrhea. "With azithromycin resistance at 7.5%, the increasing ceftriaxone MICs might soon threaten the effectiveness of this therapeutic regimen and requires close monitoring," they write.
Dec 3 BMC Infect Dis study


Procalcitonin-guided therapy reduces antibiotic duration, study finds

Originally published by CIDRAP News Dec 3

The use of an algorithm that recommends stopping antibiotics for lower respiratory tract infections (LRTIs) based on procalcitonin (PCT) levels was associated with reduced antibiotic duration without increasing adverse outcomes, researchers at an academic tertiary care hospital report today in Open Forum Infectious Diseases.

The single-center clinical trial, conducted at Johns Hopkins Bayview Medical Center, evaluated PCT-guided antibiotic therapy for LRTI by comparing antibiotic duration in a control group of 200 patients admitted prior to the intervention with antibiotic duration in a post-intervention group of 174 patients. The intervention involved daily measurements of PCT values with a rapid sensitive assay and review by an infectious disease (ID) pharmacist and an ID physician; antibiotic discontinuation was recommended if serial PCT values fell 80%.

The primary and secondary end points were total antibiotic duration per LRTI episode and antibiotic days of therapy (DOT) per 1,000 patient-days present. Overall adverse outcomes at 30 days included death, transfer to an intensive care unit, C difficile infection, and post-discharge antibiotic prescription for LRTI.

Providers complied with the PCT algorithm in 70% of encounters. Overall, the median antibiotic duration in the PCT group was lower than in the control group (5 days vs 6 days, P = 0.052), and total days of antibiotic therapy were significantly lower (1,883 vs 2,039 DOT/1,000 patient-days present).

When stratified by admitting diagnosis, median antibiotic durations were significantly shorter in the PCT group for pneumonia (6 vs 7 days, P = 0.045) and acute exacerbation of chronic obstructive pulmonary disease (AECOPD, 4 days vs 3 days, P < 0.001). Total antibiotic use was significantly shorter in the PCT group for AECOPD (788 vs. 1,513 DOT), but not for pneumonia (2,259 vs 2,360 DOT). There were no significant differences between the two groups in rates of adverse outcomes at 30 days.

The authors of the study conclude, "Overall, our study demonstrates that PCT-guided cessation of antibiotic therapy, when undertaken as a stewardship intervention, is a safe and effective strategy to reduce antibiotic use in patients with LRTI."
Dec 3 Open Forum Infect Dis abstract


'Expected Practice' may decrease antibiotic use for common infections

Originally published by CIDRAP News Dec 3

In another study today in Open Forum Infectious Diseases, researchers at the Los Angeles County + University of Southern California Medical Center report that an intervention requiring clinicians to adhere to "Expected Practice" around short-course antibiotic therapy was tied to decreased antibiotic use for common infections.

As the authors of the study explain, Expected Practice is a mechanism that educates providers about evidence-based medicine practice while also establishing an institutional requirement for standard practice. "Expected Practices set an institution's expectation for how its providers practice medicine, and hence set stronger standards of care compared to clinical guidelines, which are typically viewed more as literature-based suggestions or expert consensus," they write.

The Expected Practice around short-course antibiotic therapy was developed by a workgroup of primary and specialty care experts at the hospital and based on multiple randomized clinical trials that have demonstrated that shorter courses of antibiotics are as effective as longer courses for many common bacterial infections. Under the intervention, providers were expected to adhere to shorter antibiotic courses for common infections unless deviations could be clinically justified. The authors say one of the benefits of Expected Practice is that it alleviates provider concerns that they could be individually exposed to blame if they prescribed short-course antibiotic therapy and the clinical outcome was bad.

In a quasi-experimental pre-/post- quality improvement study, the researchers compared average antibiotic DOT and total antibiotic exposure in the 12 months prior to implementation of the intervention and the 12 months post-intervention, focusing on patients diagnosed as having urinary tract infections (UTIs), skin and other soft-tissue infections (SSTIs), pneumonia, and ventilator-associated pneumonia (VAP). When adjusted for all covariates of interest, average antibiotic DOTs decreased 10%, 11%, 11%, and 27% for UTIs, SSTIs, pneumonia, and VAP, respectively, after the introduction of Expected Practice.

Decreases for antibiotic exposure were even larger, falling by 17%, 13%, 29%, and 35% for UTIs, SSTIs, pneumonia, and VAP, respectively. An assessment of in-house mortality found no changes post-intervention.

The authors conclude that Expected Practice is a promising new psychological tool to promote effective antibiotic stewardship.
Dec 3 Open Forum Infect Dis abstract


Study: UTI management bundle cuts inappropriate antibiotics, treatment

Originally published by CIDRAP News Dec 3

Implementation of a UTI management bundle at a Canadian hospital was associated with a 75% reduction in antibiotic treatment for asymptomatic bacteriuria (AB) and improved management of UTIs, researchers reported today in Infection Control and Hospital Epidemiology.

The UTI management bundle instituted at Moncton Hospital in New Brunswick consisted of four components: nursing education, prescriber education, laboratory intervention, and pharmacy prospective audit and feedback. The intervention concentrated on appropriate indications for urine culture, UTI diagnosis, and appropriate treatment according to institutional guidelines. To determine the potential effectiveness of the bundle, researchers at the hospital conducted a retrospective chart review of consecutive inpatients with positive urinary cultures before and after implementation. Primary outcome measures included overall adherence to institutional UTI management, appropriate antibiotic use and duration of therapy, and rates of inappropriate therapy for AB.

Chart review found that, within the pre-intervention study population of 276 patients, 165 (59.8%) were found to have AB, of whom 111 (67.3%) were treated with antimicrobials. Of the 268 patients reviewed post-intervention, 133 (49.6%) were found to have AB, and 22 of the 133 (16.5%) were treated with antimicrobials. Thus, a 75.5% reduction of inappropriate AB treatment was achieved. The absolute risk reduction in AB treated after implementation of the UTI bundle was 50.8% (95% confidence interval, 40.3% to 59.3%), with a number needed to treat of two. Total days of avoidable antibiotic therapy decreased from 781 to 138 from the pre- to post-intervention periods.

In addition, educational components of the bundle were linked to a substantial decrease in nonphysician-directed urine sample submission, and adherence to a UTI management algorithm improved substantially in the intervention period, with a notable decrease in fluoroquinolone prescription for empiric UTI treatment.

"Our study has shown that the laboratory-based intervention, in both noncatheterized and catheterized patients as part of a UTI management bundle, is effective in reducing the inappropriate treatment of AB and improving overall adherence to best practice," the authors of the study conclude. 
Dec 3 Infect Control Hosp Epidemiol study

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