Campylobacter spp. in Eggs and Laying Hens in the North-East of Tunisia: High Prevalence and Multidrug-Resistance Phenotypes

Abstract

Despite the importance of eggs in the human diet, and unlike other products, for which food safety risks are widely investigated, information on the occurrence of Campylobacter and antimicrobial resistance in eggs and layer hen flocks is lacking in Tunisia. This study was conducted to determine the occurrence of Campylobacter and the antimicrobial resistance in layer hens and on eggshells. Thus, 366 cloacal swabs and 86 eggshell smear samples were collected from five layer hen farms in the North-East of Tunisia. The occurrence of Campylobacter infection, and the antimicrobial resistance rates and patterns, were analyzed. The occurrence rates of Campylobacter infection in laying hens and eggshells were 42.3% and 25.6%, respectively, with a predominance of C. jejuni (68.4%, 81.9%), followed by C. coli (31.6%, 18.2%). The antimicrobial susceptibility testing revealed high resistance rates against macrolides, tetracycline, quinolones, β-lactams, and chloramphenicol, with percentages ranging from 35.5% to 100%. All isolates were multidrug resistant (MDR) and five resistance patterns were observed. These results emphasized the risk to consumer health and the need to establish a surveillance strategy to control and prevent the emergence and the spread of resistant strains of Campylobacter in poultry and humans.

Prevalence and Antimicrobial Resistance of Campylobacter jejuni and Campylobacter coli in Wild Birds from a Wildlife Rescue Centre

“…Although it could be related to a different epidemiological situation, the lower prevalence found in Spain could also be due to the different laboratory method used to detect Campylobacter . In fact, in the Spanish study, the samples were directly plated onto selective solid media, whereas enrichment with a selective nutrient broth before solid media is usually performed in screening procedures for the isolation of Campylobacter [ 30 , 38 , 39 , 40 ].…”

Prevalence and Antimicrobial Resistance of Campylobacter jejuni and Campylobacter coli from Laying Hens Housed in Different Rearing Systems

“…A relationship has been found between the use of quinolones in poultry and increased resistance in chicken and human Campylobacter strains [ 69 ], leading to more cautious use in the poultry industry [ 72 ]. In our study, resistance to ciprofloxacin, which is the most widely used quinolone in human medicine, was detected in C. coli from laying hens in barns (flock B2: 91.7%) and aviaries (flock C1: 75%), and in C. jejuni in laying hens from cages (flock A1: 62.5%) and barns (flock B1: 60%), according to other studies where resistance rates to quinolones other than tetracycline were relevant [ 61 ] and reached 100% [ 38 ]. Resistance to erythromycin, which is the drug of choice for the treatment of campylobacteriosis in humans, was found more rarely and was detected only among C. jejuni strains, in agreement with other investigations in laying hens [ 70 , 72 ] and broilers [ 68 ].…”

“…Even if C. jejuni infection is responsible for avian vibrionic hepatitis [ 20 ], infected hens usually harbor the germ without developing clinical symptoms, spreading a large amount of Campylobacter through their feces [ 38 , 39 ]. Although the epidemiological dynamics of infection transmission in laying hen farms are not well known, their production cycles are longer than those used for broilers, exposing hens to close and constant contacts between infected and healthy individuals over several months [ 38 ]. This may explain why the incidence of infection can be high in laying hen farms.…”

“…This may explain why the incidence of infection can be high in laying hen farms. Infection rates of 70% [ 40 ], 90% [ 41 ], 97.9% [ 42 ] and up to 100% [ 43 ] have been reported in hen flocks from different countries, although lower incidence rates are also reported in the literature [ 38 , 43 , 44 , 45 , 46 , 47 ]. Several factors may influence the incidence of infection in poultry farms, and different fomites such as rodents, wild birds, visitors, equipment, drinking water and flies may carry the germ to flocks [ 48 , 49 , 50 ].…”

“…Regarding antimicrobial resistance, it has been found to be more frequent among C. coli than C. jejuni strains, according to some studies performed on laying hen farms [ 38 , 61 ]. However, in other investigations on strains from broiler [ 62 ], laying hens [ 47 , 63 ] and poultry meat [ 64 ], drug resistance was found more often in C. jejuni.…”