Antibiotic-associated haemorrhagic colitis

Helicobacter pylori Eradication Therapy-associated Diarrhea

Eradication of Helicobacter pylori has contributed to the treatment of peptic ulcers and mucosa-associated lymphoid tissue lymphoma. Moreover, it has possibly decreased the prevalence of gastric cancer. However, eradication therapy is associated with various adverse effects, of which diarrhea is the most common. The incidence of diarrhea after eradication treatment varies from 8% to 48%. In particular, the incidence is higher in patients who receive first-line standard triple therapy compared with those who receive second-line therapy. Both antibiotics and proton pump inhibitors, components of eradication therapy, have short-term and long-term impacts on gut microbiota. The alterations of gut microbiota may not recover until 1 year after eradication therapy. Most cases of diarrhea that occur after eradication therapy are antibiotic-associated diarrhea caused by the destruction of the normal gut microbiota. In some cases, Clostridioides difficile-associated diarrhea occurs after eradication therapy. If bloody diarrhea occurs after eradication therapy and the Clostridioides difficile toxin is not detected, antibiotic-associated hemorrhagic colitis associated with Klebsiella oxytoca infection should be suspected. It is crucial to explain the possibility of diarrhea before initiating eradication therapy to increase compliance. Furthermore, probiotics may be administered to reduce diarrhea. If severe diarrhea or symptoms other than the usual antibiotic-associated diarrhea occur during or after eradication therapy, antibiotics should be discontinued. In addition, appropriate tests to determine the cause of diarrhea should be performed. This review summarizes the alteration of the gut microbiota, the causes of diarrhea after Helicobacter pylori eradication therapy, and its management.

Review of Drug-induced Injury in Mucosal Biopsies From the Tubular Gastrointestinal Tract

The use of prescription and over-the-counter medications is on the rise in the US population, especially among those aged 65 and over, with over 46% of the population taking at least 1 prescription medication. Given the frequency of medication use, and that the majority of these medications are taken orally, it has become increasingly relevant for pathologist examining endoscopically obtained gastrointestinal tract mucosal biopsies to consider and recognize patterns of mucosal injury associated with various drugs. Reports on injuries associated with certain classes of drugs can be scattered among different sources, making a comprehensive view of various injury patterns and the drugs known to cause them difficult to obtain. Herein, we provide a comprehensive overview of the drugs known to cause mucosal injuries in the tubular gastrointestinal tract organized by the organ involved and the prominent pattern of injury.

A Case Report and Literature Review of Clostridium difficile Negative Antibiotic Associated Hemorrhagic Colitis Caused by Klebsiella oxytoca

Klebsiella oxytoca hemorrhagic colitis is a rare form of antibiotic associated hemorrhagic colitis that is Clostridium difficile negative. Klebsiella oxytoca colitis has been shown to be triggered by penicillin administration, yet other antibiotics have been implicated as well. It can mimic the appearance of ischemic colitis on endoscopy; however it will generally be found in young, otherwise healthy patients without risk factors. We present a case of a 33-year-old Caucasian female who presented to the emergency room with profuse, bloody diarrhea for 5 days, after a one-week course of ampicillin. Colonoscopy was notable for ulcerated mucosa with erythema and easy friability and the biopsy was suggestive of ischemic colitis. Stool culture was positive for many Klebsiella oxytoca. The patient was discharged home with resolution of symptoms after three days in the hospital. She was instructed to avoid penicillin antibiotics and minimize nonsteroidal anti-inflammatory drug use.

Prospective observational study on antibiotic-associated bloody diarrhea: report of 21 cases with a long-term follow-up from Turkey

OBJECTIVE

Antibiotic-associated hemorrhagic colitis is a distinct form of antibiotic-associated bloody diarrhea (AABD) in which Clostridium difficile is absent. Although the cause is not exactly known, reports have suggested the role of Klebsiella oxytoca and/or C. difficile.

MATERIALS AND METHODS

Between 2001 and 2006, stool samples of 21 consecutive patients with AABD were cultured for common enteric pathogens and K. oxytoca, and were tested for the presence of parasites and C. difficile toxin A+B within the first 24 h of their initial admission and a colonoscopy was performed when available. The patients were followed up prospectively by telephone interviews.

RESULTS

The occurrence of symptoms ranged between 6 h and 14 days following the first dose of the antibiotic responsible and the duration of the AABD ranged between 6 h and 21 days. The antibiotic responsible was oral ampicillin/sulbactam in 18 (85%) cases. C. difficile toxin A+B production by enzyme-linked immunosorbent assay and K. oxytoca growth in stool cultures were detected in six (29%) and 11 (51%) of 21 patients, respectively. Endoscopic morphology and histology in a limited number of patients revealed no more than a nonspecific inflammation and acute colitis, respectively.

CONCLUSION

This study confirms that antibiotic-associated hemorrhagic colitis, as a distinct entity in relation to K. oxytoca, is seen in half of the patients with AABD. Most of the cases are seen within a week following the antibiotic use. Almost all of the patients did not develop any flares during the long-term antibiotic-free follow-up. In some of the patients with AABD, there was coexistence of K. oxytoca with C. difficile toxin A+B.

Pharmacologically mediated colon ischemia

Colon ischemia (CI) is the most common form of ischemic injury of the gastrointestinal tract. Determining the precise incidence of CI is a challenging task, because of its often brief, mild nature, and frequent spontaneous resolution, as well as its misdiagnosis as other diseases. While many underlying disease conditions may predispose patients to CI, an important and possibly overlooked etiology is that of pharmacologically induced alterations of colonic blood flow. This review details the pharmacologic agents known to be associated with CI; when possible, their mechanisms of action are described. The aim of this paper is to highlight this often unrecognized cause of CI, thereby helping physicians to be aware of the association, to recognize its occurrence promptly, and to possibly reduce morbidity and mortality.

Role of antibiotic therapy for bacterial vaginosis and intermediate flora in pregnancy

Bacterial vaginosis and intermediate flora are associated with late miscarriage and preterm delivery. The mechanisms involved are not yet fully understood. Clinical trials of antibiotic therapy to reduce these complications have yielded conflicting results. These trials, however, were conducted in mixed populations of pregnant women with variable risk profiles for preterm delivery. Furthermore, investigators used different criteria for diagnosis, treated with different antibiotics at different doses and via different routes, and initiated treatment at different gestational ages. Over 80% of pregnant women with abnormal vaginal flora have a good outcome, and in some populations the presence of bacterial vaginosis is not associated with preterm delivery, suggesting that other host factors may modify the risk. Recent studies have examined the roles of genetic regulation of host immune response, bacterial pathogenic factors, and enzymes in the vagina, and how these factors interact to drive a given outcome. These markers have the potential to better define the women at maximal risk and therefore guide future interventions. This chapter aims to appraise the current state of treatment of abnormal vaginal flora in pregnancy and suggest appropriate management based on the available evidence.