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The polymerase chain reaction (PCR) after a short enrichment culture was used to detect Campylobacter spp. in chicken products. After the 16S rRNA gene sequence of Campylobacterjejuni was determined and compared with known sequences from other enterobacteria, a primer and probe combination was selected from the region before V3 and the variable regions V3 and V5. With this primer set and probe, 426-bp fragments from C. jejuni, Campylobacter coli, and Campylobacter lari could be amplified. The detection limit of the PCR was 12.5 CFU. Chicken samples inoculated with 25 CFU of Campylobacter spp. per g were PCR positive after an 18-h enrichment, which resulted in 500 CFU/ml of culture broth. This PCR-culture assay was compared with the

The application of polymerase chain reaction (PCR) fingerprinting assays enables discrimination between species and strains of microorganisms. PCR primers aiming at arbitrary sequences in combination with primers directed against the repetitive extragenic palindrome (REP) or enterobacterial repetitive intergenic consensus (ERIC) motifs generate isolate-specific DNA banding patterns. Analysis of these PCR fingerprints obtained for 33 isolates of Campylobacter jejuni, 30 isolates of Campylobacter coli, and 8 isolates of Campylobacter lari revealed that besides generation of isolate-specific fragments, species-specific DNA fragments of identical size were synthesized. It appeared that these DNA fragments could be used as species-specific probes, since they are unique for the pattern which they are deriving from. The probes do not cross-react with amplified DNA originating from a large panel of nonrelated microorganisms. Moreover, these probes displayed species specificity, as they reacted with a single restriction fragment on Southern blots containing DNA from C. jejuni, C. coli, and C. lari and other Campylobacter species. This combination of PCR fingerprinting and probe hybridization results in a highly specific identification assay and provides an example of specific test development without the prior need for DNA sequence information. The principle of the procedure holds great promise for the rapid isolation of DNA probes which, in combination with a general PCR assay, may lead to efficient typing and detection procedures for a multitude of medically important nonviral microorganisms.

Summary. The applicability of polymerase chain reaction (PCR)-mediated DNA typing, with primers complementary to dispersed repetitive DNA sequences and arbitrarily chosen DNA motifs, to study the epidemiology of campylobacter infection was evaluated. With a single PCR reaction and simple gel electrophoresis, strain-specific DNA banding patterns were observed for Campylobacter jejuni and C. upsaliensis. DNA from multiple strains isolated during an outbreak of C. jejuni meningitis generated identical banding patterns and could be distinguished from randomly isolated strains. Strains from a community outbreak of C. upsaliensis, that were all identical by conventional typing methods, could be divided into two genetically different groups. This report illustrates that PCR fingerprinting can be successfully applied in epidemiological investigations of campylobacter infections.

(1999) Suitability of the charm HVS and a microbiological multiplate system for detection of residues in raw milk at EU maximum residue levels, Veterinary Quarterly, 21:1, 21-27, DOI: 10.1080DOI: 10. /01652176.1999 Accepted for publication: October 13, 1998 SUMMARY In this paper we assessed the suitability of the Charm HVS and a newly developed microbiological multiplate system as post-screening tests to confirm the presence of residues in raw milk at or near the maximum permissible residue level (MRL). The multiplate system is composed of Bacillus stearothermophilus var. calidolactis plate at pH 8.0 for detection of beta-lactam antibiotics and tylosin, Bacillus cereus plate at pH 6.0 for detection of tetracyclines, Micrococcus luteus plate at pH 8.0 for detection of macrolides, Bacillus subtilis BGA plate at pH 8.0 for detection of aminoglycosides, trimethoprim-containing plate seeded with B. subtilis BGA at pH 7.0 for detection of sulphonamides, Escherichia coli plate at pH 6.0 for detection of quinolone and polymyxin, and Staphylococcus epidermidis plate at pH 6.0 for detection of novobiocin. For each test plate an action level is proposed in such a way that residues can be detected in raw bulk tank milk at levels near or below the established EU MRLs of beta-lactam antibiotics, tetracyclines, aminoglycosides, macrolides, sulphonamides, colistin, and quinolones. The Charm HVS test used to confirm the presence of tetracycline and macrolide residues gave false-positive results near the EU MRLs. The multiplate system gave valid results. Based on data for raw bulk tank milk samples and the proposed action level for each test plate for suspected samples, we demonstrated that the multiplate system is a reliable postscreening method that can be performed easily and cheaply in microbiological laboratories.