The evidence for clonal spreading of quinolone resistance with a particular clonal complex of Campylobacter jejuni.

Campylobacter is the most prevalent cause of bacterial gastroenteritis worldwide and it represents a significant public health risk of increasing severity due to its escalating resistance to clinically important quinolone and macrolide antibiotics. As a zoonotic pathogen Campylobacter is transmitted along the food chain and naturally cycles from environmental waters, feedstuff, animals and food to humans. We determined antibiotic resistance profiles, as well as multilocus sequence types and flaA-SVR types for 52 C. jejuni isolated in Slovenia from human, animal, raw and cured chicken meat and water samples. Twenty-eight different sequence types, arranged in ten clonal complexes, three new allele types and five new sequence types were identified, indicating the relatively high diversity in a small group of strains. The assignment of strains from different sources to the same clonal complexes indicates their transmission along the food supply chain. The most prevalent clonal complex was CC21, which was also the genetic group with 95% of quinolone-resistant strains. Based on the genetic relatedness of these quinolone-resistant strains identified by polymerase chain reaction with a mismatch amplification mutation assay and sequencing of the quinolone resistance-determining region of the gyrA gene, we conclude that the high resistance prevalence observed indicates the local clonal spread of quinolone resistance with CC21.

Anti-Campylobacter and resistance-modifying activity of Alpinia katsumadai seed extracts.

AIMS: We tested extracts from Alpinia katsumadai seeds for anti-Campylobacter activity and investigated the roles of the CmeABC and CmeDEF efflux pumps in Campylobacter resistance to these natural phenolics. Additionally, we investigated an A. katsumadai ethanolic extract (AlpE) and other plant extracts as putative efflux pump inhibitors on Campylobacter isolates and mutants in efflux pump genes. METHODS AND RESULTS: AlpE showed antimicrobial activity against sensitive and multidrug-resistant Campylobacter isolates. CmeB inactivation resulted in the greatest reduction in resistance, while cmeF and cmeR mutations produced only moderate effects on minimal inhibitory concentrations (MICs). The chemical efflux pump inhibitors additionally reduced MICs in isolates and mutants, confirming that active efflux is an important mechanism in resistance to AlpE, with additional contributions of other efflux systems. A notable decrease in resistance to tested antimicrobials in the presence of subinhibitory concentrations of AlpE confirms its modifying activity in Campylobacter spp. CONCLUSIONS: AlpE is important anti-Campylobacter source of antimicrobial compounds with resistance-modifying activity. At least two of the efflux systems are involved in the resistance to A. katsumadai antimicrobial seed extracts. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report of antimicrobial and resistance-modifying activity of AlpE from A. katsumadai seeds, demonstrating its potential in the control of Campylobacter in the food chain.

Detection and quantification of Campylobacter jejuni and Campylobacter coli using real-time multiplex PCR.

AIMS: We describe a real-time quantitative multiplex polymerase chain reaction (qmPCR) assay to identify and discriminate between isolates of Campylobacter jejuni and Campylobacter coli. METHODS AND RESULTS: Two novel sets of primers and hydrolysis probes were designed to amplify the unique DNA sequences within the hipO, ccoN and cadF genes that are specific to Camp. jejuni and Camp. coli. Using the designed optimized qmPCR assay conditions, the amplification efficiency is in range from 108 to 116%. These qmPCR assays are highly specific for Camp. jejuni and Camp. coli, as seen through testing of 40 Campylobacter strains and 17 non-Campylobacter strains. In chicken juice and tap water models spiked with known quantities of Camp. jejuni, qmPCR detected 10(2) -10(3) CFU ml(-1) within 4 h. CONCLUSIONS: The qmPCR assays developed in this study provide reliable and simultaneous detection and quantification of Camp. jejuni and Camp. coli, with good amplification reaction parameters. SIGNIFICANCE AND IMPACT OF THE STUDY: Following further validation, the qmPCR assay reported here has the potential to be applied to various sample types as an alternative and rapid methodology.