United States: CDC - Antibiotic resistance in foodborne germs is an ongoing threat

Antibiotic resistance in foodborne germs, an ongoing public health threat, showed both positive and troubling trends, according to data tracked by the Centers for Disease Control and Prevention in 2012. Each year, antibiotic-resistant infections from foodborne germs cause an estimated 430,000 illnesses in the United States. Multi-drug resistant Salmonella, from food and other sources, causes about 100,000 illnesses in the United States each year.

The most recent data showed that multi-drug resistant Salmonella decreased during the past 10 years and resistance to two important groups of drugs – cephalosporins and fluoroquinolones – remained low in 2012. However, in Salmonella typhi, the germ that causes typhoid fever, resistance to quinolone drugs increased to 68 percent in 2012, raising concerns that one of the common treatments for typhoid fever may not work in many cases.

About 1 in 5 Salmonella Heidelberg infections was resistant to ceftriaxone, a cephalapsorin drug. This is the same Salmonella serotype that has been linked to recent outbreaks associated with poultry. Ceftriaxone resistance is a problem because it makes severe Salmonella infections harder to treat, especially in children.

Among the other findings in the 2012 report:

• Campylobacter resistance to ciprofloxacin remained at 25 percent, despite FDA’s 2005 withdrawal of its approval for the use of enrofloxacin in poultry. Ciprofloxacin and enrofloxacin are both in the fluoroquinolone class of drugs.
• Shigella resistance to ciprofloxacin (2 percent) and azithromycin (4 percent) is growing. However, no Shigella strains were resistant to both drugs.
• Although fluoroquinolone resistance remained low in 2012, Salmonella enteritidis – the most common Salmonella type – accounted for 50 percent of infections resistant to the fluoroquinolone drug nalidixic acid, which is used in laboratory testing for resistance. Resistance to nalidixic acid relates to decreased susceptibility to ciprofloxacin, a widely used fluoroquinolone drug. Other work shows that many of the nalidixic acid resistant Salmonella enteritidis infections are acquired during travel abroad.