CDC repeats antibiotic resistance message

09-Jun-2015 - Last updated on 10-Jun-2015 at 10:46 GMT

Salmonella. Picture: Janice Haney Carr, Centers for Disease Control and Prevention

Antibiotic resistance in foodborne germs is an ‘ongoing public health threat’, according to the US Centers for Disease Control and Prevention (CDC), exactly the same message it delivered last year.

The agency said data continued to show positive and challenging trends in 2013, as it did in 2012.

It added efforts are underway to look at and take possible action on the use of antibiotics.

The National Antimicrobial Resistance Monitoring System (NARMS) tracks changes in antibiotic resistance of six types of foodborne germs found in ill people, retail meats and food animals.

NARMS tested more than 5,000 germs from sick people in 2013 for antibiotic resistance and compared them with previous years’ data to assess changes in resistance patterns.

Researchers compared the prevalence of resistance among isolates tested in 2013 with the average prevalence from two reference periods, 2004–2008 and the previous five years, 2008–2012.

Antibiotic-resistant infections from foodborne germs cause an estimated 440,000 illnesses each year in the US, up from the 430,000 figure reported last year.

Salmonella resistance steady

CDC said multidrug resistance (resistance to three or more classes of antibiotics) in Salmonella stayed steady, remaining at 10% of infections.

However, in some types of Salmonella it is going up with multidrug resistance in a serotype called I4,[5],12:i:- was 46%, more than double the rate from two years before.

Resistance in this serotype to four drugs (ampicillin, streptomycin, sulfonamides, and tetracycline) rose from 18% in 2011.

Human illnesses have been linked to eating pork or beef, including meats purchased from live animal markets.

A total of 3% (61/2178) of non-typhoidal Salmonella isolates were resistant to nalidixic acid with Enteritidis being the most common serotype.

Also 3% (55/2178) of non-typhoidal Salmonella isolates were resistant to ceftriaxone.

The most common serotypes among the 55 ceftriaxone-resistant isolates were Newport, Dublin, Typhimurium, Heidelberg, and Infantis.

Campylobacter and Shigella findings

One in four Campylobacter samples from sick people are resistant to quinolones like ciprofloxacin.

However, only 2% (26/1182) of Campylobacter jejuni isolates were resistant to erythromycin and azithromycin.

For Shigella, 3% (12/344) of isolates were resistant to ciprofloxacin, 5% were resistant to nalidixic acid and 4% were resistant to azithromycin.

The report includes CDC’s surveillance data for nontyphoidal Salmonella, typhoidal Salmonella (serotypes Typhi, Paratyphi A, Paratyphi B [tartrate negative], and Paratyphi C), Shigella, Campylobacter, E. coliO157, and Vibriospecies other than V. cholerae.

Surveillance data include number of isolates of each pathogen tested by NARMS and number and percentage of isolates resistant to each of the antimicrobial agents tested.

For all pathogens, isolates were categorized as resistant, intermediate (if applicable), or susceptible.