Campylobacter jejuni and Campylobacter coli are recognized as the most common causative agents of bacterial gastroenteritis in the world. Humans most often become infected by ingesting contaminated food, especially undercooked chicken, but also other sources of bacteria have been described. Campylobacteriosis is normally a self-limiting disease. Antimicrobial treatment is needed only in patients with more severe disease and in those who are immunologically compromised. The most common antimicrobial agents used in the treatment of Campylobacter infections are macrolides, such as erythromycin, and fluoroquinolones, such as ciprofloxacin. Tetracyclines have been suggested as an alternative choice in the treatment of clinical campylobacteriosis but in practice are not often used. However, during the past few decades an increasing number of resistant Campylobacter isolates have developed resistance to fluoroquinolones and other antimicrobials such as macrolides, aminoglycosides, and beta-lactams. Trends in antimicrobial resistance have shown a clear correlation between use of antibiotics in the veterinary medicine and animal production and resistant isolates of Campylobacter in humans. In this review, the patterns of emerging resistance to the antimicrobial agents useful in treatment of the disease are presented and the mechanisms of resistance to these drugs in Campylobacter are discussed.

The objective of this study was to test the prevalence of virulence-associated markers and antimicrobial resistance in 624 C. jejuni isolated from poultry food chain, i. e., chicken feces (n = 160), poultry carcasses (n = 157), poultry meat (n = 152) and from humans (n = 155). All human strains were positive for 9 out of 13 putative virulence genes responsible for expression of pathogenic factors involved in different stages of the infection. The presence of all markers was also high in strains from chicken feces, carcasses and meat although not all of them were identified in 100% of the isolates. On the other hand, the virB11, wlaN, and iam putative pathogenic genes were detected in only 1.9, 15.2, and 20.5% of strains, respectively. C. jejuni isolates, irrespective of the origin, were highly resistant to ciprofloxacin (92.5% isolates), followed by nalidixic acid (88.9%) and tetracycline (68.4%). In case of ciprofloxacin, significantly more isolates from poultry feces, carcasses and meat were resistant than those obtained from humans and the same relationship was observed for tetracycline where the isolates from chicken feces were more often resistant than C. jejuni of carcasses and meat origin. A low number of strains was resistant to streptomycin (18.4% isolates) and only 5 strains (0.8%) displayed resistance to erythromycin. A relationship between resistance to fluoroquinolones and presence of selected pathogenic markers was observed, e.g., from 83.3% strains with the virB11 to 93.4% with the docA genes were resistant to ciprofloxacin. The isolates that did not possess any of the pathogenic traits were also mainly resistant to this antimicrobial, although the number of such strains was usually low, except virB11 (612 isolates), wlaN (529 strains), and iam (496 isolates). Furthermore, resistance to tetracycline was somehow associated with the presence of the virulence associated genes wlaN and virB11 (56.8 and 75.0% isolates, respectively). The present study shows a high antimicrobial resistance to quinolones and tetracycline of C. jejuni isolated along poultry food chain and from patients with diarrhea, which was closely correlated with the presence of several virulence genes playing a role in the pathogenesis of Campylobacter infection.

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By systematically manipulating promoter and ribosome binding structures, plasmid copy number and the structure of the cholera toxin B (CTB) subunit gene, we were able to develop a plasmid expression system that, when used in conjunction with an optimized growth medium, provided yields of CTB approaching one gram per liter. The CTB protein which was secreted to > 95%, could readily be purified from the growth medium of a V. cholerae production strain and was shown to be immunologically indistinguishable from previously used vaccine preparations of native or recombinant CTB.

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Listeria monocytogenes isolates from bovine hides and carcasses (n ‫؍‬ 812) were mainly of serogroup 1/2a. All strains were positive for internalin genes. Several isolates were resistant to oxacillin (72.2%) or clindamycin (37.0%). These findings indicate that L. monocytogenes of beef origin can be considered a public health concern.

ABSTRACT:The study was conducted to investigate the presence of Campylobacter spp. in meat sold to consumers at a retail market in Poland. Antimicrobial resistance and the presence of putative virulence genes of the isolates were also examined. A total of 558 meat samples, including beef (n = 105), pork (n = 85), and poultry (n = 368) were collected over an almost three year study period. It was found that 321 samples, all of them originating from poultry, were contaminated with Campylobacter spp. Most of the obtained isolates were classified as C. coli (189 strains, 58.9%), whereas C. jejuni was identified in 132 (41.1%) samples. All Campylobacter strains were susceptible to gentamicin and all but one C. coli isolate to erythromycin. On the other hand, the highest level of resistance among Campylobacter tested was to ciprofloxacin (91% for C. jejuni and 86.1% for C. coli) and nalidixic acid (89.3% for C. jejuni and 85% for C. coli). Furthermore, resistance to two or more classes of antibiotics was found in the majority (60.9%) of Campylobacter spp. and among them one C. coli strain showed resistance to four different classes of antimicrobials. Identification of virulence genes in the isolated Campylobacter showed that all of them had the flaA and cadF genes. The iam marker was found more often in C. coli strains (88.8%) compared to C. jejuni isolates (53.8%). On the other hand, the virB11 gene was identified only in 4.2% of C. coli and in 6.1% of C. jejuni strains, respectively. Furthermore, the prevalence of the cdtA, cdtB, and cdtC genes among C. jejuni strains was 97.7%, 93.2%, 96.2%, respectively, and was significantly higher than for C. coli regarding the cdtC (66.7%) gene. The obtained results showed that the presence of Campylobacter in retail meat may represent a threat to public health.