Practice Of Infectious Diseases Research Articles

Assessment of Office‐Based Care of SexuallyTransmitted Diseases and Vaginitis and AntibioticDecision‐Making by Obstetrician‐Gynecologists

Objective: Survey office‐based obstetric‐gynecologic practitioners regarding their knowledge of infectious disease care and antibiotic use. Methods: A survey questionnaire of multiple‐choice questions was mailed to Fellows of the American College of Obstetricians and Gynecologists about clinical entities for which recommendations have undergone recent changes or about which there was a lack of consensus in a prior similar survey (Gibbs RS, McGregor JA, Mead PB, et al.: Obstet Gynecol 83:631–636, 1994).Results: Respondents indicated that oral metronidazole was their most frequent choice to treat bacterial vaginosis. Ampicillin (57%) was used more often than penicillin (39%) for intrapartum group B streptococcus prophylaxis. Azithromycin was preferred (61%) over erythromycin‐base (38%) for chlamydia treatment during pregnancy. There were several modes of practice that deviated from accepted care: 27% and 29% did not screen for chlamydia and gonorrhea, respectively, in pregnancy; 17% used cultures for Gardnerella vaginalis to diagnose bacterial vaginosis; 25% considered quinolones to be safe in pregnancy; 93% felt metronidazole should never be used in pregnancy; and the majority (66%) would send a patient treated successfully for pelvic cellulitis home with an oral antibiotic.Conclusion: Respondents’ infectious disease knowledge and practices in obstetrics and gynecology is appropriate in treating sexually transmitted diseases, bacterial vaginosis, and group B streptococcus. Numerous deficiencies still exist in screening for sexually transmitted diseases in pregnancy and diagnosing bacterial vaginosis, as well as in the choice of antibiotics to use or avoid for certain infections.

Assessment of office-based care of sexually transmitted diseases and vaginitis and antibiotic decision-making by obstetrician-gynecologists.

OBJECTIVE: Survey office-based obstetric-gynecologic practitioners regarding their knowledge of infectious disease care and antibiotic use. METHODS: A survey questionnaire of multiple-choice questions was mailed to Fellows of the American College of Obstetricians and Gynecologists about clinical entities for which recommendations have undergone recent changes or about which there was a lack of consensus in a prior similar survey (Gibbs RS, McGregor JA, Mead PB, et al.: Obstet Gynecol 83:631-636, 1994). RESULTS: Respondents indicated that oral metronidazole was their most frequent choice to treat bacterial vaginosis. Ampicillin (57%) was used more often than penicillin (39%) for intrapartum group B streptococcus prophylaxis. Azithromycin was preferred (61%) over erythromycin-base (38%) for chlamydia treatment during pregnancy. There were several modes of practice that deviated from accepted care: 27% and 29% did not screen for chlamydia and gonorrhea, respectively, in pregnancy; 17% used cultures for Gardnerella vaginalis to diagnose bacterial vaginosis; 25% considered quinolones to be safe in pregnancy; 93% felt metronidazole should never be used in pregnancy; and the majority (66%) would send a patient treated successfully for pelvic cellulitis home with an oral antibiotic. CONCLUSION: Respondents' infectious disease knowledge and practices in obstetrics and gynecology is appropriate in treating sexually transmitted diseases, bacterial vaginosis, and group B streptococcus. Numerous deficiencies still exist in screening for sexually transmitted diseases in pregnancy and diagnosing bacterial vaginosis, as well as in the choice of antibiotics to use or avoid for certain infections.

Current Status of Clinical Trials With Anti-TNF

Sepsis continues to be a prominent problem in the United States and around the world, with up to 500,000 cases per year reported in the United States alone. 1 Wenzel R Anti-endotoxin monoclonal antibodies—a second look. N Engl J Med. 1992; 326: 1151-1153 Crossref PubMed Scopus (121) Google Scholar Mortality in sepsis ranges from 20 to 50%; in patients who develop septic shock, mortality increases to 40 to 70%. 2 Young L Sepsis syndrome. in: Mandell G Bennett J Dolan R Principles and practice of infectious diseases. 4th. Churchill Livingston, New York1995: 690-705 Google Scholar , 3 Bone R Fisher CJ Clemmer T et al. A controlled clinical trial of high-dose methylprednisolone in the treatment of severe sepsis and septic shock. N Engl J Med. 1987; 317: 653-658 Crossref PubMed Scopus (1077) Google Scholar , 4 The Veterans Administration Systemic Sepsis Cooperative Study GroupEffect of high-dose glucocorticoid therapy on mortality in patients with clinical signs of systemic sepsis. N Engl J Med. 1987; 317: 659-665 Crossref PubMed Scopus (639) Google Scholar , 5 Ispahani P Pearson N Greenwood D An analysis of community and hospital-acquired bacteraemia in a large teaching hospital in the United Kingdom. QJM. 1987; 63: 427-440 PubMed Google Scholar , 6 Ziegler E Fisher CJ Sprung C et al. Treatment of Gram-negative bacteremia and septic shock with HA-1A human monoclonal antibody against endotoxin: a randomized, double-blind, placebo-controlled trial. N Engl J Med. 1991; 324: 429-436 Crossref PubMed Scopus (1280) Google Scholar , 7 Parrillo J Management of septic shock: present and future. Ann Intern Med. 1991; 115: 491-493 Crossref PubMed Scopus (43) Google Scholar , 8 Abraham E Wunderink R Silverman H et al. Efficacy and safety of monoclonal antibody to human tumor necrosis factor alpha in patients with sepsis syndrome: a randomized, controlled, double-blind, multicenter clinical trial. JAMA. 1995; 273: 934-941 Crossref PubMed Scopus (780) Google Scholar , 9 Cohen J Carlet J INTERSEPT: an international, multicenter, placebo-controlled trial of monoclonal antibody to human tumor necrosis factor-α in patients with sepsis. Crit Care Med. 1996; 24: 1431-1440 Crossref PubMed Scopus (430) Google Scholar , 10 Fisher Jr, CJ Dhainaut JF Opal SM et al. Recombinant human interleukin 1 receptor antagonist in the treatment of patients with sepsis syndrome: results from a randomized, double-blind, placebo-controlled trial. JAMA. 1994; 271: 1836-1843 Crossref PubMed Scopus (956) Google Scholar The mortality rate has remained largely constant during the postantibiotic era. The incidence of mortality from sepsis, however, has actually increased over the last l½ decades, 11 Pinner R Teutsch S Simonsen L et al. Trends in infectious diseases mortality in the United States. JAMA. 1996; 275: 189-193 Crossref PubMed Google Scholar presumably due to an aging population, an increase in the number of invasive procedures performed, and possibly alterations in the infecting micro-organisms.

Principles and Practice of Pediatric Infectious Diseases

<i>Principles and Practice of Pediatric Infectious Diseases</i>is the latest addition to the expanding number of pediatric infectious disease tomes, to which it inevitably will be compared. Like the "gold standard" in the field, Feigin and Cherry's<i>Textbook of Pediatric Infectious Diseases</i>, it is meant to be comprehensive. Unlike Feigin and Cherry, it is not encyclopedic, although it tends to greater comprehensiveness than the most recent entrant in this domain, Jenson and Baltimore's<i>Pediatric Infectious Diseases: Principles and Practice</i>. All the infectious disease texts are multiedited and multiauthored, a reflection of the breadth and depth of the subspecialty. Similarly, all have both general and specific etiologic agent sections. What are the distinguishing features of<i>Principles and Practice of Pediatric Infectious Diseases</i>, apart from its newness (a position soon and predictably to be relinquished to the fourth edition of Feigin and Cherry)? The first of the text's four major parts contains

Principles and Practice of Pediatric Infectious Diseases

Principles and Practice of Pediatric Infectious Diseases

Results of a survey of infectious disease testing practices by organ procurement organizations in the United States.

Information related to infectious disease testing policies and practices of organ procurement organizations in the United States does not currently exist. A total of 63 organ procurement organizations in the United States were surveyed during May 1996. Participants responded to a detailed questionnaire concerning infectious disease tests performed for tissue and solid organ donors and policies related to the reporting and notification of positive test results. The response rate was 77.8%. The majority of testing is performed by hospital laboratories with an expected turnaround time of 5 hr or less by 71% of organ procurement organizations. Almost all routinely perform screening tests for human immunodeficiency virus, hepatitis C virus, cytomegalovirus, syphilis, human T lymphocyte virus I, and hepatitis B surface antigen. Other tests are performed with greater variability. Although the majority of organ procurement organizations perform confirmatory tests when screening tests are positive, 35% do not perform confirmatory testing or do so only sporadically. There are a wide range of policies concerning the subsequent reporting of positive infectious disease tests and to whom results should be reported. Infectious disease testing policies of organ procurement organizations, particularly for solid organs, demonstrate variability in interpretation and perceived significance of positive test results, the initiation or need for reflex and confirmatory testing, the reporting of positive results, and to whom positive test results should be reported. There is a need for a consistent national policy for appropriate infectious disease testing and reporting of results.

Randomised trial of MNrgp120 HIV-1 vaccine in symptomless HIV-1 infection

Most individuals infected with HIV-1 show disease progression despite both cellular and humoral immune responses. We investigated whether immunisation of patients who had symptomless HIV-1 infection with an envelope subcomponent vaccine (MNrgp120) to augment immune response can slow progression of HIV-1 disease. In a randomised, double-blind, placebo-controlled trial, carried out in university infectious disease clinics and community infectious disease practices, we enrolled 573 HIV-infected patients with CD4 counts above 600 cells/microL (0.6 x 10(9)/L). Patients received 600 micrograms vaccine or placebo by intramuscular injection monthly for 6 months then every alternate month throughout the study. The primary endpoint was the rate of decline in CD4 count; secondary endpoints were HIV-1 RNA concentrations in plasma and minor clinical events associated with HIV. Analysis was by intention to treat. At baseline, the study participants had a mean CD4 count of 775 cells/microL (SD 172) and 89% of participants had detectable HIV RNA (> 200 copies/mL). These RNA-positive individuals had a median viral load of 9250 copies/mL (IQR 2670-26960). Analysis after 15 months of follow-up of the 568 subjects who had at least one CD4 count done after randomisation showed no difference between the 287 vaccine recipients and 281 placebo recipients in rate of decline of CD4 count (yearly decrease 53.8 [SE 7.6] vs 42.3 [7.6] cells/microL; ratio of mean gradients 1.27 [95% CI 0.63-2.55]) or in plasma HIV-1 RNA concentrations (p > or = 0.63). The study was designed with power to detect a vaccine-induced reduction in rate of decline in CD4 count of 60%; these results exclude with 95% confidence a reduction of 40% or more. More vaccine-treated patients than placebo recipients showed a 50% decrease in CD4 count (11 vs 5; relative risk 2.15 [95% CI 0.76-6.12], p = 0.13). The frequencies of HIV-related minor clinical events were similar in the two groups. Pain at the injection site was the only adverse event that occurred more frequently in vaccine-treated group. Postinfection immunisation of symptom-free HIV-infected patients with MNrgp120 vaccine did not alter HIV-1 disease progression as measured by immunological, virological, and clinical endpoints over a 15-month period.

Chronic Colitis After Aeromonas Hydrophilia Infection

Chronic Colitis After <i>Aeromonas Hydrophilia</i> Infection

Pasteurella Multocida Empyema

Pasteurella Multocida Empyema

Infectious disease physicians rate microbiology services and practices.

Recent years have seen increasing emphasis on cost containment and quality improvement in clinical laboratory activities. Modifying those activities to enhance clinical relevance is one strategy that should be satisfying to both laboratory scientists and administrators. This guest commentary describes one approach to quality improvement--the use of user surveys to identify areas for improvement. As an initial attempt to define such areas in clinical diagnostic microbiology, infectious disease specialists, targeted for their particular interest and expertise in microbiology laboratory results, were polled and their responses were analyzed. Some of these data have been presented previously (E. J. Baron, D. P. Francis, and K. M. Peddecord, abstr. C-170, p. 520, in Abstracts of the 94th General Meeting of the American Society for Microbiology, 1994; K. M. Peddecord, E. J. Baron, D. P. Francis, and A. S. Benenson, abstr. C-172, p. 520, in Abstracts of the 94th General Meeting of the American Society for Microbiology, 1994; K. M. Peddecord, E. J. Baron, D. P. Francis, and J. A. Drew, Am. J. Clin. Pathol. 105:58-64, 1996). The discussion includes our recommendations for the use of these survey responses, and their limitations, as stimuli to initiate reexamination of certain microbiology laboratory practices in the interest of developing more cost-effective and clinically relevant protocols.

Principles and practice of infectious diseases. Ed. 4. Edited by Gerald L. Mandell, John E. Bennett, and Raphael Dolin, 2,803 Pp. New York: Churchill Livingstone, 1995. $295

Principles and practice of infectious diseases. Ed. 4. Edited by Gerald L. Mandell, John E. Bennett, and Raphael Dolin, 2,803 Pp. New York: Churchill Livingstone, 1995. $295

Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases

Since its publication in 1979,<i>Principles and Practice of Infectious Diseases</i>(PPID) has become an essential element of every medical library. Infectious diseases clinicians have well-worn home or office copies to which they repeatedly turn. Other less complete infectious diseases texts have come and gone, but with each revision PPID remains the standard. The latest edition, a beautifully packaged two-volume opus of nearly 3000 pages, raises the measure of excellence to a new level. How does one review a book of this size? Clearly, reading every word (an estimated 2½ million words of text, not counting tens of thousands in the extensive literature citations) in each of the 302 chapters is nearly impossible. Even if one could read technical material at a breakneck and nonstop pace of 300 words per minute, over 140 hours, or more than two weeks of eight-hour days (including weekends), would be required! Lacking the luxury,

An Imported Case of Scrub Typhus

Letters to the EditorAn Imported Case of Scrub Typhus Zachariah Thomas, MD, DM Mohammed Yunus, MD Abdullah El-Subaie, and MD Kamal H. Al-AkhrasMBBS Zachariah Thomas Al-Nairiyah Hospital, Al-Nairiyah 31981, Saudi Arabia Search for more papers by this author , Mohammed Yunus Al-Nairiyah Hospital, Al-Nairiyah 31981, Saudi Arabia Search for more papers by this author , Abdullah El-Subaie Al-Nairiyah Hospital, Al-Nairiyah 31981, Saudi Arabia Search for more papers by this author , and Kamal H. Al-Akhras Al-Nairiyah Hospital, Al-Nairiyah 31981, Saudi Arabia Search for more papers by this author Published Online::25 Apr 2019https://doi.org/10.5144/0256-4947.1995.425SectionsPDF ToolsAdd to favoritesDownload citationTrack citations ShareShare onFacebookTwitterLinked InRedditEmail AboutIntroductionTo the Editor: We would like to report a case of scrub typhus in a patient who came to Saudi Arabia from India 10 days prior to the onset of his symptoms. Although this is presumed to be an imported case, the aim of this report is to remind physicians of this diagnostic possibility in patients who come from endemic areas of scrub typhus and who present with compatible clinical manifestations.A 30-year-old Indian male was admitted to Al-Nairiyah Hospital with a history of sore throat, high grade fever, headache and generalized maculopapular rash. He was mildly disoriented and complained of giddiness so much so that he could not even sit up. On examination, his temperature was 40°C. He had a maculopapular measles -like rash all over the body, mainly on the trunk. There were a few discrete tender cervical lymph nodes. The patient was confused and ataxic. There was no evidence of any eschar or mite bite mark. The rest of the examination was normal. Urinalysis showed a trace of albumin but was otherwise normal. Hb was 13.4 g/L, WBC was 7.4x10 g/L and platelet count was 117x10 g/L. Serological tests for brucella and typhoid were negative. Urine, throat and blood cultures yielded no bacterial growth. Ultrasound of the abdomen revealed no abnormalities. Chest x-ray, electrocardiogram and liver function tests were within normal limits.The patient was started on crystalline penicillin empirically as he was complaining of throat pain. He did not show any improvement even by the 5th day of hospitalization. At this stage, Weil-Felix test was performed and was positive for OX-K with a titer of 1:640 whereas OX-19 and OX-2 were negative.1 With the above clinical picture and a positive Weil-Felix test, a presumptive diagnosis of scrub typhus was made and the patient was treated with tetracycline and recovered completely. The diagnosis of scrub typhus was later confirmed by the Regional Laboratory, Dammam by indirect immunofluorescence test.2Scrub typhus is an acute febrile illness that is caused by Rickettsia tsutsugamushi. It is transmitted to humans by the bite of infected chiggers. Scrub typhus occurs in Southeast, Central and Eastern Asia, the Pacific Islands and Australia.Clinical symptoms of scrub typhus occur six to 18 days after the bite of an infected chigger and are comprised of fever, headache, myalgia and tender lymphadenopathy. The bite wound or eschar may be present in 46% of patients on examination. Other symptoms may include ocular pain, conjunctivitis, nonproductive cough and various neurologic manifestations such as apathy, delirium, tremors, slurred speech, nervousness or nuchal rigidity. The rash appears on the fifth day of illness and is usually maculopapular in nature and involves the trunk and extremities. The differential diagnosis includes typhoid fever, brucellosis, infectious mononucleosis, toxoplasmosis and dengue fever.3Tetracycline or chloramphenicol given for a period of up to two weeks are both effective in treating scrub typhus and preventing relapses; however, amelioration of symptoms may be more rapid with tetracycline. Limited studies suggest that ciprofloxacin and doxycycline may also be effective.3 Treatment shortens the illness considerably and reduces mortality and therefore early diagnosis and treatment of this condition are necessary.ARTICLE REFERENCES:1. Lennette EH, Schmidt NJ. Diagnostic Procedures for Viral, Rickettsial and Chlamydial Infections. 5th ed. New York, American Public Health Assoc, Inc, 1979. Google Scholar2. Brown GW, Shirai A, Rogers C, et al. "Diagnostic criteria for scrub typhus: probability values for immunofluorescent antibody and protein OX-K agglutinin titers" . Am J Trop Med Hyg. 1983; 32: 1101. Google Scholar3. Saah AJ. Rickettsia tsutsugamushi (scrub typhus). In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 3rd ed. Churchill Livingston Inc. 1990, 1480–2. Google Scholar Previous article Next article FiguresReferencesRelatedDetails Volume 15, Issue 4July 1995 Metrics History Published online25 April 2019 InformationCopyright © 1995, Annals of Saudi MedicinePDF download

Reviews and Notes: Infectious Diseases: Mandell, Douglass and Bennett's Principles and Practice of Infectious Diseases

Reviews and Notes: Infectious Diseases: Mandell, Douglass and Bennett's Principles and Practice of Infectious Diseases

Principles and Practice of Infectious Diseases Edited by Gerald L. Mandell, John E. Bennett, and Raphael Dolin. 4th ed. New York: Churchill Livingstone, 1995. 2,803 pp., illustrated. $249.95

Principles and Practice of Infectious Diseases Edited by Gerald L. Mandell, John E. Bennett, and Raphael Dolin. 4th ed. New York: Churchill Livingstone, 1995. 2,803 pp., illustrated. $249.95

74-Year-Old Woman With Dyspnea, Fever, and Cough

74-Year-Old Woman With Dyspnea, Fever, and Cough

The Practice of Infectious Diseases in the 1990s: The Canadian Experience

A survey of the members of the Canadian Infectious Disease Society was carried out to determine the content of an infectious diseases consultative practice in the 1990s. Respondents were asked to identify all new inpatient, outpatient, and telephone consultations during a 1-week period in 1990. Consultations were categorized by the infectious disease syndrome of the patient and by the microorganism that was identified. Bacterial infections were the most common cause of inpatient consultations, while viral infections were more common in outpatients. Consultations for parasitic infections were primarily for Pneumocystis carinii pneumonia related to infection with the human immunodeficiency virus (HIV). "Newer" infectious disease syndromes such as chronic fatigue syndrome, toxic shock syndrome, and Lyme disease were all represented in the responses for the 1-week study period. The significant impact of HIV infection on the overall consultative load suggests that there will be a continuing need for newly trained infectious disease consultants into the 21st century.

Consultation in University-Based and Community-Based Infectious Disease Practices: A Prospective Study

Infectious disease physicians in university and community practices completed a standard data form following each of 1,366 inpatient consultations during a 7-month period. The rate of consultation was higher in the university practice than in the community practice (3.4 vs. 1.8 per 100 discharges, respectively). Known or suspected bacterial pathogens accounted for more than half of all consultations in both practice groups. The three organ systems most commonly affected by infection were pulmonary (20% in university practice vs. 19% in community practice), skin and soft tissue (13% in university practice vs. 20% in community practice), and musculoskeletal (12% in university practice vs. 16% in community practice). Bloodstream infection, pneumonia, unexplained fever, osteomyelitis, urinary tract infection, and cellulitis were the six most common disease processes that led to consultation in both practice groups. The percentage of patients with noninfectious diseases and the percentage for whom a change in antimicrobial therapy was advised was nearly identical in both practice settings. Physicians in private practice performed more consultations on weekends (20% vs. 11% in university practices, P < .001) and between 6:00 P.M. and 7:00 A.M. (15% vs. 6% in university practices, P < .001). The scope and diversity of the work of consultants in community practices are nearly identical to those of their colleagues in university-based practices.

Evaluation of a Commercial System for the Identification of Gram-Negative, Nonfermenting Bacteria of Veterinary Importance

8. Ferris KE, Miller DA: 1990, Salmonella serotypes from animals and related sources reported during July 1989-June 1990. Proc Annu Meet US Anim Health Assoc 94:463-478. 9. Ferris KE, Miller DA: 1991, Salmonella serotypes from animals and related sources reported during July 1990-June 1991. Proc Annu Meet US Anim Health Assoc 95:440-454. 10. Ferris KE, Miller DA: 1992, Salmonella serotypes from animals and related sources reported during July 1991-June 1992. Proc Annu Meet US Anim Health Assoc 96:492-504. 11. Gibbons DF: 1980, Equine salmonellosis: a review. Vet Rec 106:356-359. 12. Hird DW, Casebolt DB, Carter JD, et al.: 1986, Risk factors for salmonellosis in hospitalized horses. J Am Vet Med Assoc 188:173-177. 13. Hird DW, Pappaioanou M, Smith BP: 1984, Case control study of risk factors associated with isolation of Salmonella saint paul in hospitalized horses. Am J Epidemiol 120:852-864. 14. Hook EW: 1990, Salmonella species (including typhoid fever). In: Principles and practice of infectious diseases, ed. Mandell GL, Douglas RG, Bennett JE, 3rd ed., pp. 1700-1716. Churchill Livingston, New York, NY. 15. Ikeda JS, Hirsh DC: 1985, Common plasmid encoding resistance to ampicillin, chloramphenicol, gentamicin, and trimethoprim-sulfadiazine in two serotypes of Salmonella isolated during an outbreak of equine salmonellosis. Am J Vet Res 46:769773. 16. Ikeda JS, Hirsh DC, Jang SS, Biberstein EL: 1986, Characteristics of Salmonella isolated from animals at a veterinary medical teaching hospital. Am J Vet Res 47:232-235. 17. Lund LJ, Atkinson WI, Holt GJ: 1991, Transmission of Salmonella to veterinarians. Vet Rec 129:415. 18. Mathewson JJ, Simpson RB, Roush DA: 1981, Isolation of antibiotic-resistant Salmonella krefeld from clinical veterinary materials. Antimicrob Agents Chemother 19:355-356. 19. Morse EV, Duncan MA, Fessler JF, Page EH: 1976, The treatment of salmonellosis in Equidae. Mod Vet Pract 57:47-51. 20. Morse EV, Duncan MA, Page EA, Fessler JF: 1976, Salmonellosis in Equidae: a study of 23 cases. Cornell Vet 66:198213. 21. National Committee for Clinical Laboratory Standards: 1990, Approved standard M2-A4. Performance standards for antimicrobial disk susceptibility tests. National Committee for Clinical Laboratory Standards, Villanova, PA. 22. National Committee for Clinical Laboratory Standards: 1990, Approved standard M7-A2. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically. National Committee for Clinical Laboratory Standards, Villanova, PA. 23. National Committee for Clinical Laboratory Standards: 1992, Fourth information supplement M100-S4. Performance standards for antimicrobial susceptibility testing. National Committee for Clinical Laboratory Standards, Villanova, PA. 24. Owen RR, Fullerton J, Barnum DA: 1983, Effects of transportation, surgery, and antibiotic therapy in ponies infected with Salmonella. Am J Vet Res 44:46-50. 25. Palmer JE, Benson CE: 1984, Salmonella shedding in the equine. Proc Int Symp Salmonella, pp. 161-164. 26. Smith BP: 1981, Equine salmonellosis: a contemporary view. Equine Vet J 13:147-151.

Host-Microbe Interaction in the Gastrointestinal Tract

In order for an infection to occur, the target organ must come in contact with sufficient microbes, the microbe must possess specific virulence factors, these virulence factors must be expressed, and the defenses of the organ system must be overcome. This dynamic process, which is ongoing in all living entities, can be described by the following relationship: [formula: see text] The establishment of infection first occurs in a particular organ. This phenomenon is known as tissue trophism and the association of microbes with organ systems governs the practice of clinical microbiology and infectious disease. With some microbes (e.g., Giardia, Cryptosporidium) the interaction with the particular organ is so specific that infections are almost always confined to one site; with others (e.g., Salmonella, enterovirus) the microbe has the potential to become systemic. When attempting to establish health risk assessment from microbes by contact with food and drinking water, one must therefore consider that the gastrointestinal tract is a complex organ system with a variety of specific host defense mechanisms. It is only when the microbe has particular virulence factors for sites in gastrointestinal tract, and the specific host defense mechanisms in the gastrointestinal tract are breached, that infection of this organ system occurs. Therefore, the general terms "immunosuppression" or "immunocompromise" are meaningless unless the specific immune defect is known. A description of the microbial virulence factors active against the gastrointestinal tract and the defense mechanisms of this organ system are reviewed to provide a biological basis health risk assessment and future food and drinking water regulations.