flaA-like sequences containing internal termination codons (TAG) in urease-positive thermophilic Campylobacter isolated in Japan

AIMS

To demonstrate two flaA-like sequences containing two internal termination codons (TAG) in two Japanese strains of urease-positive thermophilic Campylobacter (UPTC).

METHODS AND RESULTS

A primer pair of A1 and A2, which ought to generate a product of approx. 1700 bp of the flaA gene for Campylobacter jejuni, was used to amplify products of approx. 1450 bp for two Japanese strains of UPTC, CF89-12 and CF89-14. After molecular cloning and sequencing, the nucleotide sequences of the amplicons from the two strains were found to be 1461 bp in length and to have nucleotide sequence differences in relation to each other at four nucleotide positions, respectively.

CONCLUSIONS

Nucleotide and amino acid sequence alignment and homology analysis demonstrated that the polymerase chain reaction (PCR) amplicons from the two Japanese strains have approx. 83% nucleotide and 80% amino acid sequence homology to the possible open reading frame of the flaA gene of UPTC NCTC 12892.

SIGNIFICANCE AND IMPACT OF THE STUDY

Surprisingly, both PCR amplicons from the Japanese UPTC have two internal termination codons (TAG) at nucleotide positions from 775 to 777 and 817 to 819, respectively.

Cloning and sequencing of 16S rDNA and 16S-23S rDNA internal spacer region (ISR) from urease-positive thermophilic Campylobacter (UPTC)

AIMS

To clone and sequence the 16S rDNA and 16S-23S rDNA internal spacer region (ISR) from urease-positive thermophilic Campylobacter (UPTC).

METHODS AND RESULTS

The primer sets for 16S rDNA and 16S-23S rDNA ISR amplified almost the full length of 16S rDNA and 16S-23S rDNA ISR. About 1500 bp for 16S rDNA and about 720 bp for 16S-23S rDNA ISR of the rrn operon of four strains of UPTC were identified after molecular cloning and sequencing.

CONCLUSIONS

The four strains and CCUG18267 of UPTC showed approximately 99% sequence homology of 16S rDNA to each other, 96-97% to Camp. coli, 97-98% to Camp. jejuni and 97-98% to Camp. lari.

SIGNIFICANCE AND IMPACT OF THE STUDY

For the first time, the nucleotide sequence of 16S-23S rDNA ISR of UPTC has been analysed. The sequence of ISR was almost identical among the four strains of UPTC. It is interesting that the UPTC intercistronic tRNAs demonstrated an order of tRNA of 5'-16S-tRNAAla-tRNAIle-23S-3' in the organisms.

Urease-positive thermophilic strains of Campylobacter isolated from seagulls (Larus spp.)

Three strains of urease-positive thermophilic Campylobacter (UPTC), designated A1, A2 and A3, were identified by biochemical characterization after isolation from faeces of seagulls in Northern Ireland in 1996. The biochemical characteristics of the strains were identical to those of strains described previously. Analysis by pulsed-field gel electrophoresis (PFGE) after separate digestion with ApaI and SmaI demonstrated that the respective PFGE profiles were indistinguishable. The PFGE analysis also suggested that the genomes were approximately 1810 kb in length. This is the first example of the isolation of UPTC from flying homoiothermal animals, i.e. from seagulls (Larus spp.).

The effect of a new sewage treatment plant on faecal indicator numbers, campylobacters and bathing water compliance in Morecambe Bay

Until recently, sewage from Morecambe was macerated, but otherwise untreated, and discharged at high water via a short outfall pipe into Morecambe Bay adjacent to a recognized bathing water. In March 1997, a new biological sewage treatment plant came on-line and the effluent was discharged via a longer outfall pipe into the Bay south of Heysham. The effect of the new sewage treatment on the quality of the bathing waters was monitored by testing sea water collected from the three EU designated bathing waters on Morecambe Bay: Morecambe North, Morecambe South and Heysham. After sewage treatment came on-line, the numbers of faecal coliforms and faecal streptococci were lower at Morecambe North and Morecambe South but higher at Heysham. Although the changes in numbers were not always statistically significant, they were sufficient to affect compliance with the EU Bathing Water Directive Imperative (mandatory) standards. Compliance improved markedly at Morecambe North and South but declined at Heysham, the closest bathing site to the new outfall. Numbers of thermophilic campylobacters were similar in both years, which is suggestive of their sources being different from those of the indicator bacteria. Campylobacter lari and urease-positive thermophilic campylobacters (UPTC) were the only species of Campylobacter isolated from Morecambe's bathing waters. Very low numbers of Salmonella were found, with Salm, arizonae the only species isolated.