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The Pediatric Infectious Disease Journal® Newsletter

McCracken, George H. Jr. M.D.; Nelson, John D. M.D.

The Pediatric Infectious Disease Journal: June 2013 - Volume 32 - Issue 6 - p A15–A16
doi: 10.1097/01.inf.0000430812.30343.52

PLESIOMONAS INFECTION We recently managed a 16 year old male with poorly controlled Crohn’s disease who was receiving immunosuppression therapy with adalimumab (Humira), a TNF inhibitor, and methotrexate. He experienced 2 weeks of worsening abdominal pain and bloody diarrhea. Tenderness was evident on palpation of the lower abdominal quadrants. Abdominal CT showed extensive inflammatory changes in the right lower quadrant involving principally the terminal ileum and a possible ruptured appendix. The stool culture yielded Plesiomonas shigelloides that was believed to be a pathogen in this patient. His diarrhea and pain improved after initiating therapy with piperacillin-tazobactam. The organism is a facultative anaerobic Gram-negative rod belonging to the family Vibrionaceae. It is found in tropical freshwater fish and shellfish and has been associated with aquariums and fish tanks. The patient had frequently visited a Texas lake where he often swallowed water while swimming. Most infections in humans are self-limited and associated with fever, abdominal pain and non-bloody diarrhea lasting only several days to a week. Because of our patient’s inflammatory bowel disease and immunosuppression he had prolonged symptoms that responded well to antimicrobial therapy (Written in collaboration with Dr Michal Meir, a fellow in our division).

PERSISTENCE OF VARICELLA VACCINE IMMUNITY Until licensure and routine immunization with the varicella vaccine in the mid-1990s most children developed chicken pox and a small percentage of these had complications, the most common of which was cellulitis of the lesions as a result of scratching. Hospitalization was required in some of these latter patients because of extensive infection and occasionally necrotizing fasciitis. Data from the prospective study conducted by the excellent investigators at Kaiser Permanente Vaccine Study Center in Oakland, CA showed vaccine efficacy of at least 90% among approximately 7500 children followed since 1995 when they received their first varicella vaccine dose (Pediatrics 2013; 131: 1). The two-dose regimen implemented in 2006 was calculated to be approximately 98% effective for up to 5 years and severe disease is now rarely encountered. Most of those with breakthrough varicella had mild disease with fewer than 50 lesions (>300 lesions was common before the vaccine) and the complications seen before are rarely encountered today. This has been an outstanding achievement.

ANTIBIOTIC PRESCIPTIONS Many factors affect prescribing habits of physicians. Did you know that race is one of those factors? According to Jeff Gerber and colleagues at The Children’s Hospital of Philadelphia and the University of Pennsylvania, physicians in 25 different practices in southeastern Pennsylvania and southern New Jersey were 25% less likely to prescribe an antibiotic to black children with an acute upper respiratory tract infection than they were to non-black children (Pediatrics 2013; 131: 677). The authors point out that black children were also less likely to receive a diagnosis that would prompt such therapy. The explanation is not readily apparent, but it seems possible to us that parental demand, either perceived or real, could have influenced the final decision as to whether antibiotics should be given. It is unlikely that black children had fewer infections requiring therapy since their demographic characteristics, including daycare attendance, were similar to their counterparts.

CONGENITAL RUBELLA We have been around long enough to have experienced the last major rubella epidemic in the United States in 1964 that involved approximately 20,000 cases of congenital rubella syndrome resulting in 2100 neonatal deaths (MMWR 2013; 62:226). Following licensure of rubella vaccine in 1971 and implementation of a universal vaccination policy in 2004, endemic transmission of the virus was eliminated in the United States. We cannot recall when we last saw an infant with congenital rubella syndrome and it is now rarely listed in the differential diagnosis of congenital infection offered by medical students and residents. However, rubella still occurs commonly in some areas of the world and rarely an infant with congenital infection is encountered in the United States as a result of maternal infection acquired in a foreign country. Since 2004 there have been 5 such cases, 3 of which are detailed in the Morbidity and Mortality Weekly Report referenced above.

BACTERIA INSTEAD OF BARIATRIC SURGERY? In the United States the old expression “fat of the land” has come to mean the people who live here. Each year about 200,000 of them undergo bariatric surgery after attempts at diet and exercise have failed. Most of them shed a lot of pounds after the surgery. Sometimes it is a prodigious amount of weight and more than one would expect from the mechanical re-routing of the gastric bypass procedure. An article by Denise Grady in the March 28, 2013 issue of The New York Times cites recently published studies pointing to a role of altered intestinal microflora following bariatric surgery that might impact nutrition. More than 50 years ago a book written by the microbiologist Theodore Rosebury titled Life in Man created almost as much public interest as Rachel Carson’s Silent Spring had a decade earlier. Rosebury pointed out that the total number of living bacterial cells in each person’s intestine exceed the total number of humans cells of all types in that person’s body. Alterations in the microflora of the gut can have profound effects, for example, when antibiotics are taken. It is known that the gut flora changes after bariatric surgery. It would be interesting to transplant the new gut flora from a bariatric surgery patient to an obese person digests to see whether the new flora led to weight loss. That experiment would be difficult to justify ethically, but similar experiments have been done in mice with positive results. Could different types of bacteria have an opposite effect, i. e. cause obesity by enhancing utilization of nutrients? Fat people are more likely than others to harbor Methanobrevibacter smithii, an organism that digests certain nutrients and makes more calories available for absorption. It is clear that the interrelations we have with our intestinal bacteria are complex. It is not crazy to think that one day we might see fecal transplants used for controlled weight gain or loss. Stranger things have happened. Think about the Helicobacter-peptic ulcer story.

ANTIBIOTIC RESISTANCE AND ANIMAL FEEDS David Kessler was Commissioner of the Food and Drug Administration during the 1990s. In an op-ed essay (NY Times, March 28, 2013) Dr. Kessler quoted Alexander Fleming, the discoverer of penicillin, who said in 1945 in his Nobel Prize acceptance speech, “There is a danger that the ignorant man may easily underdose himself and by exposing his microbes to nonlethal quantities of the drug make them resistant.” If Dr. Fleming had been more prescient he would have said “underdose himself or animals” because animals are currently the main consumers of antibiotics. In 2011 drug makers sold 30 million pounds of antibiotics given to animals. That was 80% of all antibiotic sales in the U.S. in 2011. The evidence is overwhelming that antibiotics given to animals are a major factor (perhaps the major factor) in our problems with antibiotic resistance of bacteria. It is also true that subtherapeutic amounts of antibiotics given to animals make them grow faster and get fatter and that is a huge economic advantage. Dr. Kessler urges government action to control the practice of putting antibiotics in animal feed, but that action is strongly opposed by drug companies and people who raise the animals and it seems to be as unlikely to happen as gun control legislation. The “ignorant man” referred to by Dr. Fleming may be your congressman.

© 2013 Lippincott Williams & Wilkins, Inc.