Antibiotic resistance in some types of Salmonella infections is increasing. The Centers for Disease Control and Prevention (CDC) published data Tuesday on the resistance in foodborne pathogens from human isolates. The National Antimicrobial Resistance Monitoring System (NARMS) tracks changes in the antibiotic resistance of six types of common foodborne germs found in ill people, retail meats, and food animals. In 2013, NARMS tested more than 5,000 germs from sick people for antibiotic resistance and compared them with previous years’ data to assess changes in resistance patterns.
Multi-drug resistance (resistance to 3 or more classes of antibiotics) in Salmonella overall stayed steady, remaining at 10 percent of infections. But resistance varies by serotype. Salmonella Enteritidis — the most common Salmonella serotype — accounted for 36 percent of infections resistant to nalidixic acid (resistance to nalidixic acid relates to decreased susceptibility to ciprofloxacin, a widely used fluoroquinolone drug). Salmonella serotypes Dublin, Heidelberg, Newport, and Typhimurium accounted for more than two-thirds of infections resistant to ceftriaxone. Most concerning was that 46 percent of the common Salmonella serotype called I 4,[5],12:i:- were multi-drug resistant in 2013. That’s more than double the 18-percent resistance rate in 2011. Human illness with this serotype has been linked to animal exposure and consumption of pork or beef, including meats purchased from live animal markets. The 2013 data also showed that there has been little change in Campylobacter resistance to fluoroquinolones. For example, Ciprofloxacin resistance in Campylobacter jejuni, the most common species isolated from humans, remains high at 22 percent, and macrolide resistance in Campylobacter coli doubled from 9 percent to 18 percent. Most Salmonella and Campylobacter infections cause diarrheal illness that resolves within a week without antibiotics. These germs can also cause infection of the bloodstream and other sites. In more serious infections and when germs are resistant, antibiotics may be ineffective, increasing the chance of a severe illness. Each year, antibiotic-resistant infections from foodborne pathogens cause an estimated 440,000 illnesses in the U.S.
