Antibiotic resistance of campylobacter low in Finland
Finnish Food Safety Authority Evira was included in a research team that charted the resistance to antibiotics and connections to genotype of campylobacter isolated from humans and domestic sources of infection. The study focused on Campylobacter jejuni, the most common species of campylobacter causing gastrointestinal inflammation in humans. The results of the study confirm the previous findings of low antibiotic resistance of production animals in Finland.
Campylobacter is most commonly transmitted to humans through food, and broilers are considered the key source of infection ofCampylobacter jejuni. Humans may also become infected with Campylobacter jejuni through water, animals or animal droppings.
“The study included determining antimicrobial susceptibility to six types of antibiotics. The resistance to each type of antibiotic was studied by using isolates obtained from both humans and animals. The results of the study showed that approximately 5 % ofCampylobacter jejuni in broilers, nearly 17 % of Campylobacter jejuni in bovines and almost 12 % of Campylobacter jejuni in humans were resistant to at least one of the studied types of antibiotic,” says Senior Researcher Satu Olkkola.
Antibiotics not usually necessary in treating campylobacter infections in humans
However, antibiotics are needed in treating serious infections or infections that have become more common, as well as in treating certain risk groups. The most commonly used antimicrobial agents in such cases are from the macrolide or quinolone groups of antibiotics. Resistance to quinolones is common among the campylobacter found in the EU area.
“Based on the study, resistance to quinolones was also the most common type of antimicrobial resistance among the Campylobacter jejuni isolated from humans and bovines in Finland; approximately 8% of the bacteria in humans and more than 9 % of the bacteria in bovines were resistant to quinolones. None of the bacteria studied were found to be resistant to marcolides. However, the resistance to quinolones was also low compared to most other European countries,” says Olkkola.
The reason for the low antibiotic resistance found in Finland could be, among others, the low usage of antibiotics on production animals by international comparison, meaning that the bacteria do not develop a resistance to antibiotics.
The study comprised 850 Campylobacter jejuni pure cultures, or isolates, of which 459 originated from broilers and 120 from bovines. 95 of the isolates originated from infected humans. The study also included isolates obtained from natural waters, wild birds and a zoo.
Associations between sequence type and resistance were also studied
Genotyping data was exploited in the study in order to identify any associations between sequence type and resistance.
In previous studies, the Campylobacter jejuni isolates were genotyped by using the MLST (Multilocus sequence typing) technique in which bacterial species are typed on the basis of the central allelic profile, or sequence type, of seven housekeeping genes.
In the total data, nearly half (12/26) of the isolates resistant to tetracycline were also resistant to streptomycin. Most of these isolates originated from zoo animals and broilers and belonged to the clonal complex CC 1034, which is rare in humans and production animals. Other significant associations between resistance and sequence type were not identified.
The study has been published in an internationally peer-reviewed scientific publication:
Olkkola, S., Nykäsenoja, S., Raulo, S., Llarena, A.-K., Kovanen, S., Kivistö, R., Myllyniemi, A.-L., Hänninen, M.-L. Antimicrobial Resistance and Multilocus Sequence Types of Finnish Campylobacter jejuni Isolates from Multiple Sources. Zoonoses and Public Health 2016: 63, pp. 10–19.
For further information, please contact:
Satu Olkkola, Senior Researcher, tel. +358 40 489 3456, Food and Feed Microbiology Research Unit