A polymerase chain reaction (PCR) for the specific detection of Helicobacter pylori was developed with a single primer pair derived from the nucleotide sequence of the urease A gene of H. pylori. We achieved specific amplification of a 411-bp DNA fragment in H. pylori. After 35 cycles of amplification, the product could be detected by agarose gel electrophoresis and contained conserved single HinfI and AluI restriction sites. This fragment was amplified in all 50 strains of H. pylori tested, but it was not detected in other bacterial species, showing the PCR assay to be 100% specific. PCR DNA amplification was able to detect as few as 10 H. pylori cells. PCR detected H. pylori in 15 of 23 clinical human gastric biopsy samples, whereas culturing and microscopy detected H. pylori in only 7 of the samples found to be positive by PCR. Additional primer pairs based on the urease genes enabled the detection of H. pylori in paraffin-embedded human gastric biopsy samples. The detection of H. pylori by PCR will enable both retrospective and prospective analyses of clinical samples, elucidating the role of this organism in gastroduodenal disease.

No abstract

No abstract

No abstract

Summary.The clinical importance of the gram-positive anaerobic cocci (GPAC) isolated in 1987 at St Bartholomew's Hospital, London, is assessed. Of about 800 anaerobic isolates, 209 (27 YO) were GPAC, of which 67 (32%) were from abscesses and 22 (11 YO) were in pure growth. Four species comprised 77% of the 168 isolates available for study: Peptostreptococcus magnus (55 isolates, 33 YO), P. micros (23, 14 YO), P. asaccharolyticus (24, 14 Yo) and P. anaerobius (27, 16 YO). Different species were associated with different sites, from P. magnus (usually skin-associated sites ; normally cultured with aerobes, infrequently with other anaerobes), P. asaccharolyticus (distributed widely) and P. anaerobius (usually genitourinary and gastrointestinal; always below the diaphragm) to P. micros (always deep sites with other anaerobes). P. magnus was isolated from 15 abscesses and was obtained in pure culture from 11 specimens, six of them abscesses developing from infected sebaceous cysts. P. micros was usually isolated from soft tissue abscesses, never from the skin, and with a characteristic mixed flora consisting of " Streptococcus milleri" and anaerobic gram-negative rods. P. heliotrinreducens was a rare isolate from similar specimens. P. asaccharolyticus was cultured from a wide variety of sites, typically mixed with both aerobes and anaerobes, and frequently from abscesses. Most isolates of P. anaerobius came from gastrointestinal or female genitourinary specimens, never from above the diaphragm and rarely from the skin; cultures were usually heavily mixed. Isolates of P. vaginalis and the " bGAL" group made up 11 YO of strains and were usually cultured from superficial sites, P. vaginalis often from post-operative wound infections with Staphylococcus aureus. There were only two isolates of P. hydrogenalis, three of P. tetradius and none of P. barnesae, P. prevotii, P. lacrimalis, P. lactolyticus, P. productus or Peptococcus niger. GPAC are a heterogeneous group associated with a wide variety of infections, particularly abscesses, and are frequently isolated in pure culture. They deserve further study.