The Case Study – by; Debra Ann Meuler, Department of Natural Sciences, Cardinal Stritch University Google. Figure 1: Electron micrograph of H. pylori with multiple flagella (negative staining). Dr. Robin Warren The story begins with Dr. J. Robin Warren. Dr. Warren was a pathologist at the Royal Perth Hospital (RPH) in Western Australia. A pathologist is a medical doctor who examines tissues and is responsible for the accuracy of laboratory tests. Pathologists interpret the results of these examinations and tests and provide information important for a patient’s diagnosis and recovery. Part of Warren’s duties as a pathologist was to examine histological sections from gastric biopsies. With the arrival in the early 1970s of the fiberoptic endoscope, it was increasingly common to find good, well-fixed sections from gastrointestinal tissue. Prior to this, it was unusual for a pathologist to see good histological sections from any part of the stomach that was not post mortem. In 1979, after examining a hematoxylin and eosin-stained section of a stomach biopsy from a man with severe gastritis, Warren noticed a thin blue line on the surface of the tissue. When he increased magnification, he thought he saw bacteria. Google -Figure 2. A hematoxylin and eosin stained section of a stomach biopsy showing the presence of bacteria on the surface of cells. To get a better look at these bacteria, Warren ordered a Warthin-Starry silver stain of the histological section. Silver staining deposits silver granules on some types of bacteria, making them larger and more pronounced. The stain revealed numerous spiral shaped bacteria. This was a bit surprising since, according to medical textbooks, bacteria were not supposed to colonize the stomach. Intrigued, Warren began requesting Warthin-Starry silver stain for all the gastric biopsies he examined. He began to see a pattern. There was a definite correlation between active, chronic gastritis and the presence of these bacteria. He also observed that the number of bacteria seemed to correlate with the degree of inflammation of the stomach lining—the more severe the inflammation, the more abundant the bacteria. But this didn’t make sense. Medicine taught that the stomach was sterile. It was too acidic for any bacteria to survive for very long. Bacteria in the stomach had been reported before, but dismissed as a contaminant or as secondary to the problem. Warren, however, didn’t believe his spiral bacteria were simply a contaminant. Electron microscopy revealed bacteria attached to the mucosa and infiltrating between the tops of cells—an area not reached by ingestion. Also, because of the large numbers and homogeneity of colonization, he believed they were actively multiplying and living in the stomach lining. What was even more peculiar to Warren was that the bacteria were associated with gastritis. Histological gastritis is diagnosed when sections of stomach biopsies show infiltration of tissue with lymphocytic-type cells, small collections of neutrophils, micro-erosions, epithelial cell damage, and a decrease in the thickness of the mucus layer. If Warren saw this type of histological presentation in biopsies, the bacteria were usually present. When Warren discussed his findings with colleagues, they were unconvinced as to the importance of the findings and asked for more data. The stomach was a sterile environment, so Warren’s bacteria were more than likely an artifact. Despite the unenthusiastic response, Warren held to his belief that these bacteria were important and tried to recruit others to his study.