Foodborne bacterial infections are becoming harder to treat, according to a report on antimicrobial resistance from EFSA and ECDC.
Salmonella and Campylobacter are increasingly resistant to ciprofloxacin, one of the main antibiotics for treating infections they cause, said the European Centre for Disease Prevention and Control (ECDC) and European Food Safety Authority (EFSA).
Data from humans, animals and food show a large proportion of Salmonella bacteria are multidrug-resistant, which means they are resistant to three or more antimicrobials. In 2017 and 2018, data on antimicrobial resistance in bacteria was provided by 28 member states and analyzed by EFSA and ECDC.
Results for Salmonella in humans
In Salmonella spp. from human cases in 2018, resistance to ampicillin, sulfonamides and tetracyclines were at high levels, particularly among serovars common in pigs. A decline in resistance to ampicillin and tetracyclines in Salmonella Typhimurium from humans was observed in several countries from 2013 to 2018.
Resistance to gentamicin was overall low except for Salmonella Kentucky where it was very high. Also, levels of chloramphenicol were low but moderate in Salmonella Typhimurium.
In humans, resistance to ciprofloxacin is common, particularly in certain types of Salmonella, and resistance to high concentrations of ciprofloxacin increased from 2016. Ciprofloxacin is a fluoroquinolone, a class of antimicrobials categorized as critically important for use in humans. Both agencies warned that if they lose effectiveness, the impact on human health could be “significant”.
For antimicrobials cefotaxime and ceftazidime, representing third generation cephalosporins, resistance levels were generally low. Combined resistance to ciproﬂoxacin and cefotaxime was low in Salmonella spp. but higher in Salmonella Infantis and Salmonella Kentucky.
Only seven and eight countries tested resistance to last line antimicrobials azithromycin and tigecycline, respectively, but resistance was overall low. Resistance to colistin was detected in 7.8 percent of isolates but most were either Salmonella Enteritidis or Salmonella Dublin.
Sporadic cases of human Salmonella infection have been found with resistance to carbapenems, a last-line antimicrobial. For another last-line antimicrobial, resistance to colistin was not common in Salmonella and E. coli.
Mike Catchpole, ECDC’s chief scientist, said finding carbapenem resistance in foodborne bacteria in the EU was a concern.
“The most effective way to prevent the spread of carbapenem-resistant strains is to continue screening and responding promptly to positive detections. ECDC is working with EU member states and with EFSA in a one health approach to enhance the early detection and monitoring, in an effort to fight the persisting threat of antimicrobial-resistant zoonotic infections.”
Data on Campylobacter in humans
Decreasing trends in occurrence of extended-spectrum beta-lactamase (ESBL) or AmpC-producing E. coli have been observed in about 40 percent of member states from 2015 to 2018. This is important because ESBL-AmpC-producing E. coli are responsible for serious infections in humans.
For Campylobacter, 16 of 19 countries reported very or extremely high percentages of ciprofloxacin resistance. The proportion of human Campylobacter jejuni isolates resistant to erythromycin was low overall but higher in Campylobacter coli.
High and extremely high proportions of resistance to tetracycline were observed in Campylobacter jejuni and Campylobacter coli. Low proportions of isolates were resistant to gentamicin and amoxicillin-clavulanic acid.
Multi-drug resistance in isolates tested for four antimicrobial classes (ﬂuoroquinolones, macrolides, tetracyclines and aminoglycosides) was low in Campylobacter jejuni but moderate in Campylobacter coli. The most common pattern was resistance to ciproﬂoxacin and tetracycline.
Monitoring and reporting of antimicrobial resistance (AMR) in 2017 and 2018 included data on indicator E. coli isolates. Some countries reported voluntary data on occurrence of meticillin‐resistant Staphylococcus aureus in animals and food.
Marta Hugas, EFSA’s chief scientist, said antimicrobial resistance was a serious threat to global public and animal health.
“The positive findings in food-producing animals are encouraging because they are a sign of improvement. However, we need to further investigate the reasons behind this change,” Hugas said.
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