The data in the report is collected through the National Antimicrobial Resistance Monitoring System (NARMS) and contains data from January 2014 – June 2015.

The new report measures antimicrobial resistance in Salmonella isolated from raw retail meat and poultry. Information includes serotype distribution, prevalence by food source and state, selected resistance patterns, and a list of all the identified antimicrobial resistance genes.

Encouraging Trends

In many important categories, encouraging improvements found in 2011 continued to be evident in the latest data.

The prevalence of Salmonella in retail poultry is at its lowest level since testing began in 2002. In ground turkey, the prevalence of Salmonella has declined from a high of 19 per cent in 2008 to 6 per cent in 2014. In retail chicken over the same time period, it has dropped from 15 per cent to 9 per cent.

Salmonella resistance to ceftriaxone (an important antibiotic used to treat seriously ill patients) from chicken sources continued to decline steadily from a high of 38 per cent in retail chicken meats in 2009 to 18 per cent in 2014, and 5 per cent during the first half of 2015.

In ground turkey isolates, ceftriaxone resistance was detected in 7 per cent of 2014 isolates and 4 per cent of 2015 isolates collected through June, which represents an 80 per cent decline since 2011 when resistance peaked at 22 per cent.

Fluoroquinolones like ciprofloxacin are classified as critically important for the treatment of Salmonella infections. Ciprofloxacin resistance was absent in Salmonella from poultry and beef, although a single isolate was found in pork.

All Salmonella from retail meats were susceptible to azithromycin, another important antibiotic recommended for the treatment of Salmonella and other intestinal pathogens.

Multidrug resistance in Salmonella continued to show a downward drift in chicken and turkey from 2011 levels of 45 per cent and 50 per cent, respectively, to 20 per cent and 36 per cent in June 2015.

Findings of Concern

FDA identified the first instance of ciprofloxacin resistance in an isolate from retail pork, and identified the genes associated with this resistance for future tracking.

One ceftriaxone-resistant retail chicken isolate from 2014 had the extended-spectrum β-lactamase (ESBL) gene blaCTX-M-65.

This is the first time this important class of resistance gene was detected in the US. This ESBL gene causes resistance to β-lactam antibiotics, including third generation cephalosporins, resulting in fewer treatment options for infected patients.

While only three isolates of Salmonella serotype Dublin were recovered from meats (ground beef) in 2014, they exhibited extensive resistance patterns as in the past, showing resistance to 9-12 of 14 drugs tested.

Further Reading

You can view the full report by clicking here.