Antibiotics and Clostridium difficile diarrhea in the ambulatory care setting

In Vitro and In Vivo Anti-Clostridioides difficile Effect of a Probiotic Bacillus amyloliquefaciens Strain

Clostridioides difficile infection (CDI) is a significant cause of hospital-acquired and antibiotic-mediated intestinal diseases and is a growing global public health concern. Overuse of antibiotics and their effect on normal intestinal flora has increased the incidence and severity of infections. Thus, the development of new, effective, and safe treatment options is a high priority. Here, we report a new probiotic strain, Bacillus amyloliquefaciens (BA PMC-80), and its in vitro/in vivo anti-C. difficile effect as a prospective novel candidate for replacing conventional antibiotics. BA PMC-80 showed a significant anti-C. difficile effect in coculture assay, and its cell-free supernatant (CFS) also exhibited a considerable anti-C. difficile effect with an 89.06 μg/ml 50% minimal inhibitory concentration (MIC) in broth microdilution assay. The CFS was stable and equally functional under different pHs, heat, and proteinase treatments. It also exhibited a high sensitivity against current antibiotics and no toxicity in subchronic toxicity testing in hamsters. Finally, BA PMC-80 showed a moderate effect in a hamster CDI model with reduced infection severity and delayed death. However, further studies are required to optimize the treatment condition of the hamster CDI model for better efficacy and identify the antimicrobial compound produced by BA PMC-80.

[Use of antimicrobials in acute canine diarrhea - overview of potential risks, indications and alternatives]

In Germany, antibiotics are frequently used in dogs with gastrointestinal disorders such as acute diarrhea. In line with global efforts to limit antibiotic use, this literature review aims to provide a guideline for the rational and judicious use of antibiotics in acute canine diarrhea. Antibiotics can lead to gastrointestinal side effects and may exert a negative influence on the intestinal microbiota in addition to increasing the occurrence of resistant bacteria. There is also evidence that chronic immunological diseases may be triggered by the administration of antibiotics. Therefore, these should not be administered in uncomplicated acute diarrhea without signs of sepsis or systemic inflammatory reaction. In addition, enteropathogenic bacteria usually do not play a role in the etiology of acute diarrhea. For select clinical entities such as acute hemorrhagic diarrhea syndrome, antibiotic therapy should only be recommended in cases displaying signs of bacterial translocation with subsequent sepsis. In the case of parvovirosis, on the other hand, the administration of antibiotics is unavoidable due to the immunological incompetence of the dog caused by the accompanying severe neutropenia.

Calculated parenteral initial therapy of bacterial infections: Antibiotic treatment in the elderly

This is the fifteenth chapter of the guideline “Calculated initial parenteral treatment of bacterial infections in adults – update 2018” in the 2^nd updated version. The German guideline by the Paul-Ehrlich-Gesellschaft für Chemotherapie e.V. (PEG) has been translated to address an international audience.

Multimorbidity, an atypical symptomatology of infections in combination with multimedication, the associated interaction risks and serious consequences of synergistic side effects characterize the conditions when deciding on the use of antibiotics in old age. Strict decision regarding the indication itself, choice of the best antibiotic even considering rare side effects which may be dangerous in the elderly, determining the correct dose, dosing interval and the shortest possible duration according to the physiological status of the patient as well as monitoring effectiveness and toxicity detect expected and unexpected side effects early. Recommendations must reflect the peculiarities of antibiotic treatment in elderly patients.

The Epidemiology of Community Clostridium difficile Infection: A Five-Year Population-Based Study on the Bailiwick of Jersey, Channel Islands

We studied healthcare-associated and community-associated Clostridium difficile infection (CDI) in Jersey, Channel Islands (2008–2012). The Island’s stable population has reliable denominator data, a clearly defined at-risk population, and healthcare contact that is easily followed. The vast majority of CDI cases had had recent healthcare contact, and true community-associated disease is extremely rare.

Infect Control Hosp Epidemiol 2018;39:603–607

Clinical Practice Guidelines for Clostridium difficile Infection in Adults: 2010 Update by the Society for Healthcare Epidemiology of America (SHEA) and the Infectious Diseases Society of America (IDSA)

Since publication of the Society for Healthcare Epidemiology of America position paper onClostridium difficileinfection in 1995, significant changes have occurred in the epidemiology and treatment of this infection.C. difficileremains the most important cause of healthcare-associated diarrhea and is increasingly important as a community pathogen. A more virulent strain ofC. difficilehas been identified and has been responsible for more-severe cases of disease worldwide. Data reporting the decreased effectiveness of metronidazole in the treatment of severe disease have been published. Despite the increasing quantity of data available, areas of controversy still exist. This guideline updates recommendations regarding epidemiology, diagnosis, treatment, and infection control and environmental management.

Prevalence of Clostridium difficile infection presenting to US EDs

OBJECTIVE

The objective of the study is to determine the prevalence of Clostridium difficile infection (CDI) presenting to emergency departments (EDs) in the United States. Secondary objectives included defining the burden of CDI.

METHODS

This is a retrospective, observational cohort study of 2006-2010 Nationwide Emergency Department Sample database of 980 US hospital EDs in 29 states. Prevalence, mortality rate, length of stay, hospital charges, and endemicity were measured.

RESULTS

A total of 474513 patients with CDI-related ED visits were identified. From 2006 to 2010, the prevalence of CDI increased from 26.2 to 33.1 per 100,000 population (P<.001). The number of CDI-related ED cases increased 26.1% (P<.001) over the study period: 18.6% from 2006 to 2007 (P<.001), 4.3% from 2007 to 2008 (P=.46), 1.8% from 2008 to 2009 (P=.73), and 0.13% from 2009 to 2010 (P=.95). Emergency department visits occurred more frequently with individuals 85 years or older (relative risk [RR], 13.74; P<.001), females (RR, 1.77; P<.001) and in the northeast United States (RR, 1.42; P<.001). From 2009 to 2010, the mortality rate decreased 17.9% (P=.01).

CONCLUSIONS

The prevalence of CDI presenting to EDs increased each year from 2006 to 2010; however, the rate of increase slowed from each year to the next. The mortality rate increased from 2006 to 2009 and decreased significantly from 2009 to 2010. C difficile infection visits presenting to EDs occurred more frequently with older individuals, females, and in the northeast.

Missed diagnosis of Clostridium difficile infection; a prospective evaluation of unselected stool samples

BACKGROUND

Clostridium difficile infection (CDI) is the leading cause of hospital-acquired diarrhoea in developed countries, however a high proportion of CDI episodes go undiagnosed, either because physicians do not request identification of toxigenic C. difficile or microbiologists do not perform the appropriate tests.

OBJECTIVE

To investigate the clinical characteristics of patients with CDI within a non-selected population and to determine risk factors for clinical underdiagnosis.

METHODS

We conducted a prospective study in which systematic testing for toxigenic C. difficile on all diarrhoeic stool samples was performed regardless of the clinician's request. Patients aged >2 years positive for toxigenic C. difficile and diarrhoea were enrolled (Jan-June 2013) and monitored at least 2 months after their last episode.

RESULTS

We identified 204 cases of CDI, of which three-quarters were healthcare-associated. Most cases were mild to moderate (83.8%), the recurrence rate was 16.2%, and CDI-related mortality was low (2.5%). A significant proportion (12.7%) of CDI cases would have been missed owing to lack of clinical suspicion. Community-acquired cases and young age were risk factors for clinical underdiagnosis.

CONCLUSION

Our data support the introduction of a systematic search for toxigenic C. difficile in all diarrhoeic stools from inpatients and outpatients older than 2 years.

Community-associated Clostridium difficile infection and antibiotics: a meta-analysis

OBJECTIVES

Antibiotic exposure is the most important risk factor for Clostridium difficile infection (CDI). Most evaluations of antimicrobial risk factors have been conducted in healthcare settings. The objective of this meta-analysis was to evaluate the association between antibiotic exposure and community-associated CDI (CA-CDI) (i.e. symptom onset in the community with no healthcare facility admission within 12 weeks) and to determine the classes of antibiotics posing the greatest risk.

METHODS

We searched four electronic databases for subject headings and text words related to CA-CDI and antibiotics. Studies that investigated the risk of CA-CDI associated with antibiotic usage were considered eligible. Data from the identified studies were combined using a random-effects model and ORs were calculated.

RESULTS

Of 910 citations identified, eight studies (n = 30 184 patients) met our inclusion criteria. Antibiotic exposure was associated with an increased risk of CA-CDI (OR 6.91, 95% CI 4.17-11.44, I(2) = 95%). The risk was greatest with clindamycin (OR 20.43, 95% CI 8.50-49.09) followed by fluoroquinolones (OR 5.65, 95% CI 4.38-7.28), cephalosporins (OR 4.47, 95% CI 1.60-12.50), penicillins (OR 3.25, 95% CI 1.89-5.57), macrolides (OR 2.55, 95% CI 1.91-3.39) and sulphonamides/trimethoprim (OR 1.84, 95% CI 1.48-2.29). Tetracyclines were not associated with an increased CDI risk (OR 0.91, 95% CI 0.57-1.45).

CONCLUSIONS

Antibiotic exposure was an important risk factor for CA-CDI, but the risk was different amongst different antibiotic classes. The risk was greatest with clindamycin followed by fluoroquinolones and cephalosporins, whereas tetracyclines were not associated with an increased risk.

Meta-analysis of antibiotics and the risk of community-associated Clostridium difficile infection

The rising incidence of Clostridium difficile infection (CDI) could be reduced by lowering exposure to high-risk antibiotics. The objective of this study was to determine the association between antibiotic class and the risk of CDI in the community setting. The EMBASE and PubMed databases were queried without restriction to time period or language. Comparative observational studies and randomized controlled trials (RCTs) considering the impact of exposure to antibiotics on CDI risk among nonhospitalized populations were considered. We estimated pooled odds ratios (OR) for antibiotic classes using random-effect meta-analysis. Our search criteria identified 465 articles, of which 7 met inclusion criteria; all were observational studies. Five studies considered antibiotic risk relative to no antibiotic exposure: clindamycin (OR = 16.80; 95% confidence interval [95% CI], 7.48 to 37.76), fluoroquinolones (OR = 5.50; 95% CI, 4.26 to 7.11), and cephalosporins, monobactams, and carbapenems (CMCs) (OR = 5.68; 95% CI, 2.12 to 15.23) had the largest effects, while macrolides (OR = 2.65; 95% CI, 1.92 to 3.64), sulfonamides and trimethoprim (OR = 1.81; 95% CI, 1.34 to 2.43), and penicillins (OR = 2.71; 95% CI, 1.75 to 4.21) had lower associations with CDI. We noted no effect of tetracyclines on CDI risk (OR = 0.92; 95% CI, 0.61 to 1.40). In the community setting, there is substantial variation in the risk of CDI associated with different antimicrobial classes. Avoidance of high-risk antibiotics (such as clindamycin, CMCs, and fluoroquinolones) in favor of lower-risk antibiotics (such as penicillins, macrolides, and tetracyclines) may help reduce the incidence of CDI.

Clostridium difficile: a European perspective

Clostridium difficile infection is the leading cause of diarrhoea in the industrialised world. First identified in 1935, our knowledge about the clonal population structure, toxins and PCR ribotypes is still increasing. New PCR ribotypes and sequence types are frequently added. In the last decade hypervirulent strains have emerged and been associated with increased severity of disease, high recurrence and significant mortality. Although previously a primarily hospital- or health-care acquired infection, since the 1990's C. difficile infections that are community-acquired have been increasingly reported. Risk factors include hospitalisation, advancing age and prior antibiotic use. The ubiquitous presence of C. difficile in the environment and asymptomatic intestinal colonisation may be important reservoirs for infection and the changing epidemiology of C. difficile infection. Although surveillance in Europe is now a requirement of the European Commission, reporting is not standardised or mandatory. Here we review the current literature, guidelines on diagnosis and treatment and conclude by highlighting a number of areas where further research would increase our understanding.

Community-associated Clostridium difficile infections, Monroe County, New York, USA

Judicious use of antimicrobial drugs will reduce infections.

Clostridium difficile infection: the scope of the problem

Clostridium difficile infection (CDI) is increasingly common, and it is associated with significant morbidity, mortality, and cost burden for patients and the healthcare system. The severity and rates of recurrent CDI and associated mortality are also increasing. This article is an overview of the changes in CDI epidemiology that have occurred since the turn of the century and the current scope of the problem. The 3 articles that follow in this supplement address the diagnosis and treatment of initial and recurrent CDI, and current practice guidelines for the prevention and control of CDI in the hospital setting.

Cumulative antibiotic exposures over time and the risk of Clostridium difficile infection

BACKGROUND

Clostridium difficile infection (CDI) is a major cause of hospital-acquired diarrhea and is most commonly associated with changes in normal intestinal flora caused by administration of antibiotics. Few studies have examined the risk of CDI associated with total dose, duration, or number of antibiotics while taking into account the complex changes in exposures over time.

METHODS

A retrospective cohort study conducted from 1 January to 31 December 2005 among hospitalized patients 18 years or older receiving 2 or more days of antibiotics.

RESULTS

The study identified 10,154 hospitalizations for 7,792 unique patients and 241 cases of CDI, defined as the detection of C. difficile toxin in a diarrheal stool sample within 60 days of discharge. We observed dose-dependent increases in the risk of CDI associated with increasing cumulative dose, number of antibiotics, and days of antibiotic exposure. Compared to patients who received only 1 antibiotic, the adjusted hazard ratios (HRs) for those who received 2, 3 or 4, or 5 or more antibiotics were 2.5 (95% confidence interval [CI] 1.6-4.0), 3.3 (CI 2.2-5.2), and 9.6 (CI 6.1-15.1), respectively. The receipt of fluoroquinolones was associated with an increased risk of CDI, while metronidazole was associated with reduced risk.

CONCLUSIONS

Cumulative antibiotic exposures appear to be associated with the risk of CDI. Antimicrobial stewardship programs that focus on the overall reduction of total dose as well as number and days of antibiotic exposure and the substitution of high-risk antibiotic classes for lower-risk alternatives may reduce the incidence of hospital-acquired CDI.

The changing epidemiology of Clostridium difficile infections

The epidemiology of Clostridium difficile infection (CDI) has changed dramatically during this millennium. Infection rates have increased markedly in most countries with detailed surveillance data. There have been clear changes in the clinical presentation, response to treatment, and outcome of CDI. These changes have been driven to a major degree by the emergence and epidemic spread of a novel strain, known as PCR ribotype 027 (sometimes referred to as BI/NAP1/027). We review the evidence for the changing epidemiology, clinical virulence and outcome of treatment of CDI, and the similarities and differences between data from various countries and continents. Community-acquired CDI has also emerged, although the evidence for this as a distinct new entity is less clear. There are new data on the etiology of and potential risk factors for CDI; controversial issues include specific antimicrobial agents, gastric acid suppressants, potential animal and food sources of C. difficile, and the effect of the use of alcohol-based hand hygiene agents.

The changing epidemiology of Clostridium difficile infections

The epidemiology of Clostridium difficile infection (CDI) has changed dramatically during this millennium. Infection rates have increased markedly in most countries with detailed surveillance data. There have been clear changes in the clinical presentation, response to treatment, and outcome of CDI. These changes have been driven to a major degree by the emergence and epidemic spread of a novel strain, known as PCR ribotype 027 (sometimes referred to as BI/NAP1/027). We review the evidence for the changing epidemiology, clinical virulence and outcome of treatment of CDI, and the similarities and differences between data from various countries and continents. Community-acquired CDI has also emerged, although the evidence for this as a distinct new entity is less clear. There are new data on the etiology of and potential risk factors for CDI; controversial issues include specific antimicrobial agents, gastric acid suppressants, potential animal and food sources of C. difficile, and the effect of the use of alcohol-based hand hygiene agents.

Risk factors for and estimated incidence of community-associated Clostridium difficile infection, North Carolina, USA

We determined estimated incidence of and risk factors for community-associated Clostridium difficile infection (CA-CDI) among patients treated at 6 North Carolina hospitals. CA-CDI case-patients were defined as adults (>18 years of age) with a positive stool test result for C. difficile toxin and no hospitalization within the prior 8 weeks. CA-CDI incidence was 21 and 46 per 100,000 person-years in Veterans Affairs (VA) outpatients and Durham County populations, respectively. VA case-patients were more likely than controls to have received antimicrobial drugs (adjusted odds ratio [aOR] 17.8, 95% confidence interval [CI] 6.6-48] and to have had a recent outpatient visit (aOR 5.1, 95% CI 1.5-17.9). County case-patients were more likely than controls to have received antimicrobial drugs (aOR 9.1, 95% CI 2.9-28.9), to have gastroesophageal reflux disease (aOR 11.2, 95% CI 1.9-64.2), and to have cardiac failure (aOR 3.8, 95% CI 1.1-13.7). Risk factors for CA-CDI overlap with those for healthcare-associated infection.

Systematic review and meta-analysis of Saccharomyces boulardii in adult patients

This article reviews the evidence for efficacy and safety of Saccharomyces boulardii (S. boulardii) for various disease indications in adults based on the peer-reviewed, randomized clinical trials and pre-clinical studies from the published medical literature (Medline, Clinical Trial websites and meeting abstracts) between 1976 and 2009. For meta-analysis, only randomized, blinded controlled trials unrestricted by language were included. Pre-clinical studies, volunteer studies and uncontrolled studies were excluded from the review of efficacy and meta-analysis, but included in the systematic review. Of 31 randomized, placebo-controlled treatment arms in 27 trials (encompassing 5029 study patients), S. boulardii was found to be significantly efficacious and safe in 84% of those treatment arms. A meta-analysis found a significant therapeutic efficacy for S. boulardii in the prevention of antibiotic-associated diarrhea (AAD) (RR = 0.47, 95% CI: 0.35-0.63, P < 0.001). In adults, S. boulardii can be strongly recommended for the prevention of AAD and the traveler's diarrhea. Randomized trials also support the use of this yeast probiotic for prevention of enteral nutrition-related diarrhea and reduction of Helicobacter pylori treatment-related symptoms. S. boulardii shows promise for the prevention of C. difficile disease recurrences; treatment of irritable bowel syndrome, acute adult diarrhea, Crohn's disease, giardiasis, human immunodeficiency virus-related diarrhea; but more supporting evidence is recommended for these indications. The use of S. boulardii as a therapeutic probiotic is evidence-based for both efficacy and safety for several types of diarrhea.

Clostridium difficile is not associated with outbreaks of viral gastroenteritis in the elderly in the Netherlands

The coincidental increase in norovirus outbreaks and Clostridium difficile infection (CDI) raised the question of whether these events could be related, e.g. by enhancing spread by diarrhoeal disease outbreaks. Therefore, we studied the prevalence of C. difficile in outbreaks of viral gastroenteritis in nursing homes for the elderly and characterised enzyme immunoassay (EIA)-positive stool samples. Stool samples from nursing home residents (n = 752) in 137 outbreaks of viral aetiology were investigated by EIA for the presence of C. difficile toxins. Positive samples were further tested by a cell neutralisation cytotoxicity test, a second EIA and culture. Cultured isolates were tested for the presence of toxin genes, the production of toxins and characterised by 16S rRNA polymerase chain reaction (PCR) and sequencing. Twenty-four samples (3.2%) tested positive in the EIA. Of these 24 positive samples, only two were positive by cytotoxicity and three by a second EIA. Bacterial culture of 21 available stool samples yielded a toxinogenic C. difficile PCR ribotype 001 in one patient sample only. In conclusion, we found no evidence in this retrospective study for an association between viral gastroenteritis outbreaks and C. difficile. The high rate of false-positive EIA samples emphasises the need for second confirmation tests to diagnose CDI.

Antibiotic-associated diarrhea: epidemiology, trends and treatment

A common complication of antibiotic use is the development of gastrointestinal disease. This complication ranges from mild diarrhea to pseudomembranous colitis. Outbreaks of antibiotic-associated diarrhea (AAD) may also occur in healthcare settings, usually caused by Clostridium difficile. AAD typically occurs in 5-35% of patients taking antibiotics and varies depending upon the specific type of antibiotic, the health of the host and exposure to pathogens. The pathogenesis of AAD may be mediated through the disruption of the normal microbiota resulting in pathogen overgrowth or metabolic imbalances. The key to addressing AAD is prompt diagnosis followed by effective treatment and institution of control measures. Areas of active research include the search for other etiologies and more effective treatments.

Gastric acid suppression by proton pump inhibitors as a risk factor for clostridium difficile-associated diarrhea in hospitalized patients

BACKGROUND

Evidence for the association between Clostridium difficile (C. difficile) and the use of proton pump inhibitor (PPI) is unclear. This study investigated the relationship between Clostridium difficile-associated diarrhea (CDAD) and exposure to acid suppressive therapy in hospitalized adult patients while controlling for the most common predisposing risk factors.

METHODS

A retrospective case-control study was conducted at a local hospital of all hospitalized patients between October 1, 2005 and September 30, 2006 who developed CDAD during hospitalization. Subjects were determined to have CDAD if there was a positive C. difficile toxin and clinical correlation of diarrhea at the time of diagnosis. Subjects were pair-matched to controls on the following factors: admission date, antibiotic exposure, gender, age groups, patient location (medical or surgical unit), and room type at time of admission. Seven risk factors were assessed for association with onset of CDAD: exposure to PPIs or H(2)-blockers, renal failure, diabetes mellitus, immunosuppression, malignancy, and gastrointestinal disease.

RESULTS

Ninety-four cases were successfully matched to controls. Cases were more likely than controls to receive acid suppressive therapy during hospitalization, 72 (76.6%) versus 40 (42.6%), respectively, P= 0.030. In a multivariate exact conditional logistic regression analysis, CDAD was associated with use of PPI (odds ratio [OR]= 3.6, 95% confidence interval [CI]= 1.7-8.3; P < 0.001), and with renal failure (OR = 5.7, CI = 1.3-39.1; P= 0.02).

CONCLUSION

This study showed elevated risk of developing CDAD in hospitalized patients with acid suppressive therapy, especially when PPIs were used.

A case-control study of community-associated Clostridium difficile infection

OBJECTIVES

The aim of this study was to determine the incidence of and risk factors for community-associated Clostridium difficile infection (CDI).

METHODS

Prospective surveillance of community-derived faecal samples for C. difficile cytotoxin, followed by a questionnaire-based case-control study in two distinct patient cohorts (one semi-rural and the other urban).

RESULTS

The proportion of randomly selected faecal samples positive for C. difficile cytotoxin was 2.1% in both patient cohorts (median ages 73 and 45 years for the urban and semi-rural cohorts, respectively). Exposure to antibiotics in the previous 4 weeks, particularly multiple agents (P < 0.001), aminopenicillins (P < 0.05) and oral cephalosporins (P < 0.05), was significantly more frequent among cases than controls. Hospitalization in the preceding 6 months was significantly associated with CDI (45% versus 23%; P = 0.022). However, almost half the cases had not received antibiotic therapy in the month before C. difficile detection, and approximately one-third neither had exposure to antibiotics nor recent hospitalization. Contact with infants aged < or =2 years was significantly associated with CDI (14% versus 2%; P = 0.02). Prior exposure to gastrointestinal-acting drugs (proton pump inhibitor, H2 antagonist or non-steroidal anti-inflammatory) was not significantly more common in CDI cases. C. difficile PCR ribotype 001 caused 60% and 13% of urban and semi-rural community-associated CDI cases, respectively.

CONCLUSIONS

Reliance on antibiotic history and age (> or =65 years) will contribute to missed diagnoses of community-associated CDI. Potential risk factors for community-associated CDI should be explored further to explain the large proportion of cases not linked to recent antibiotic therapy or hospitalization.

Diarrheal diseases in the elderly

Diarrhea in the elderly population is one disease that needs special attention in treatment and management, especially in acute- and long-term care residents, because of their multiple comorbidities, immunosenescence, frailty, and poor nutritional status. Close follow-up to ensure adequate hydration and electrolyte replacement and infection control measures to contain outbreaks should be emphasized to caregivers and nursing staff in acute- and long-term care facilities. Although C difficile colitis causes significant morbidity and mortality in this population, judicious use of antibiotics is important to decrease the incidence and recurrence of the disease. When the diarrhea is chronic and all stool testings and serologies have been performed, the patient may benefit from endoscopy and colonoscopy for biopsy. Attentive and vigilant nursing staff is crucial in the timely diagnosis and treatment of diarrheal diseases to improve quality of life and reduce mortality.

Fluoroquinolone use and risk factors for Clostridium difficile-associated disease within a Veterans Administration health care system

BACKGROUND

Prompted by the changing profile of Clostridium difficile infection and the impact of formulary policies in hospitals, we performed this study when an increase in the incidence of C. difficile-associated disease was noted at our health care center (Veterans Administration Puget Sound Health Care System, Seattle, Washington).

METHODS

A retrospective, matched case-control study of patients presenting to the Veterans Administration Puget Sound Health Care System, Seattle, Washington during 2004 was performed. Conditional logistic analysis determined risk factors for case patients, defined as individuals with diarrhea and test results (i.e., culture or toxin assay results) positive for C. difficile, and control subjects, defined as individuals with diarrhea and test results negative for C. difficile.

RESULTS

C. difficile-associated disease incidence was 29.2 cases per 10,000 inpatient-days. The increase in the incidence of C. difficile-associated diarrhea that paralleled increased gatifloxacin use was not attributable to use of the antimicrobial but was a reflection of seasonal variation in the rate of C. difficile-associated disease. Multivariate analysis controlling for the time at which the assay was performed, the age of the patient, ward, and source of acquisition (community-acquired vs. nosocomial disease) found 6 significant risk factors for C. difficile-associated diarrhea: receipt of clindamycin (adjusted odds ratio [aOR], 29.9; 95% confidence interval [CI], 3.58-249.4), receipt of penicillin (aOR, 4.1; 95% CI, 1.2-13.9), having a lower intestinal condition (aOR, 2.8; 95% CI, 1.3-6.1), total number of antibiotics received (aOR, 1.4; 95% CI, 1.1-1.7), number of prior hospital admissions (aOR, 1.3; 95% CI, 1.1-1.6), and number of comorbid conditions (aOR, 1.3; 95% CI, 1.1-1.5).

CONCLUSIONS

The increase in the number of cases of C. difficile-associated disease was not attributable to a formulary change of fluoroquinolones; instead, the incidence was within expected seasonal variations for C. difficile-associated disease. Recognition of community-acquired cases and the use of culture may help to identify additional cases of C. difficile-associated disease. Early diagnosis and treatment of C. difficile cases may shorten the duration of hospital stays and reduce the number of outbreaks and readmissions, mortality, and other consequences of C. difficile infection.

A possible role for Clostridium difficile in the etiology of calf enteritis

Clostridium difficile was investigated as a possible cause of enteritis in calves. The organism and its toxins (TcdA and TcdB), respectively, were found in 25.3% and 22.9% of stool samples from diarrheic calves. Culture positive samples were more likely than culture negative samples to be toxin positive. However, toxin positive stools were more common among nondiarrheic calves, but diarrheic calves were nearly twice as likely to be culture positive. Ribotype 078 was dominant among isolates. Salmonella sp. was isolated from both diarrheic and nondiarrheic calves, but large numbers of E. coli were found more commonly in diarrheic calves than in nondiarrheic animals. Prevalence rates for coronavirus and Cryptosporidium sp. were substantially higher in nondiarrheic calves than in diarrheic, but rates of detection of rotavirus and Giardia sp. were more nearly equal between groups. Lesions in naturally infected calves included superficial mucosal erosion with associated fibrinous exudates. Neutrophils and eosinophils infiltrated lamina propria. Large Gram-positive rods morphologically compatible with C. difficile were abundant in the colonic lumen and the organism was isolated by bacteriologic culture. Toxins were found throughout the colon. Purified toxins A and B (individually and conjointly) caused comparable lesions, as well as fluid accumulation, in ligated intestinal loops. Our findings are in substantial agreement with those of others [Rodriguez-Palacios, A., Stampfli, H.R., Duffield, T., Peregrine, A.S., Trotz-Williams, L.A., Arroyo, L.G., Brazier, J.S., Weese, J.S., 2006. Clostridium difficile PCR ribotypes in calves, Canada. Emerg. Infect. Dis. 12, 1730–1736; Porter, M.C., Reggiardo, C., Bueschel, D.M., Keel, M.K., Songer, J.G., 2002. Association of Clostridium difficile with bovine neonatal diarrhea. Proc. 45th Ann. Mtg. Amer. Assoc. Vet. Lab. Diagn., St. Louis, MO, U.S.A.] and add strength to a working hypothesis that C. difficile infection and the accompanying intoxication can manifest as diarrhea in calves. It seems clear that calves serve as multiplying hosts for this organism.

Onset of symptoms and time to diagnosis of Clostridium difficile-associated disease following discharge from an acute care hospital

OBJECTIVE

To identify patients with a diagnosis of Clostridium difficile-associated disease (CDAD) in the ambulatory care setting and determine the relationship of symptom onset and diagnosis to prior hospitalization and exposure to antimicrobials.

DESIGN

Single-center, retrospective study.

METHODS

Medical records were reviewed for outpatients and hospitalized patients with a stool assay positive for C. difficile toxin A from January 1998 through March 2005. Patients with recurrent CDAD or residing in an extended-care facility were excluded. CDAD in patients who had been hospitalized in the 100 days prior to diagnosis was considered potentially hospital-associated.

RESULTS

Of the 84 patients who met the inclusion criteria, 75 (89%) received a diagnosis 1-60 days after hospital discharge (median, 12 days), and 71 (85%) received a diagnosis within 30 days after discharge. Of the 69 patients whose records contained information regarding time of symptom onset, 62 (90%) developed diarrhea within 30 days of a previous hospital discharge, including 7 patients with symptom onset prior to discharge and 9 with onset on the day of discharge. The median time from symptom onset to diagnosis was 6 days. Of 84 patients, 77 (92%) had received antimicrobials during a prior hospitalization, but 55 (65%) received antimicrobials both as inpatients and as outpatients.

CONCLUSION

If all cases of CDAD diagnosed within 100 days of hospital discharge were assumed to be hospital-associated, 71 (85%) of 84 patients with CDAD were identified within 30 days, and 75 (89%) of 84 were identified by day 60. Continued outpatient antimicrobial exposure confounds determination of whether late-onset cases are community- or hospital-associated.

Implications of the changing face of Clostridium difficile disease for health care practitioners

Recent reported outbreaks of Clostridium difficile-associated disease in Canada have changed the profile of C difficile infections. Historically, C difficile disease was thought of mainly as a nosocomial disease associated with broad-spectrum antibiotics, and the disease was usually not life threatening. The emergence of an epidemic strain, BI/NAP1/027, which produces a binary toxin in addition to the 2 classic C difficile toxins A and B and is resistant to some fluoroquinolones, was associated with large numbers of cases with high rates of mortality. Recently, C difficile has been reported more frequently in nonhospital-based settings, such as community-acquired cases. The C difficile disease is also being reported in populations once considered of low risk (children and young healthy women). In addition, poor response to metronidazole treatment is increasing. Faced with an increasing incidence of C difficile infections and the changing profile of patients who become infected, this paper will reexamine the current concepts on the epidemiology and treatment of C difficile-associated disease, present new hypotheses for risk factors, examine the role of spores in the transmission of C difficile, and provide recommendations that may enhance infection control practices.

Recommendations for surveillance of Clostridium difficile-associated disease

BACKGROUND

The epidemiology of Clostridium difficile-associated disease (CDAD) is changing, with evidence of increased incidence and severity. However, the understanding of the magnitude of and reasons for this change is currently hampered by the lack of standardized surveillance methods.

OBJECTIVE AND METHODS

An ad hoc C. difficile surveillance working group was formed to develop interim surveillance definitions and recommendations based on existing literature and expert opinion that can help to improve CDAD surveillance and prevention efforts.

DEFINITIONS AND RECOMMENDATIONS

A CDAD case patient was defined as a patient with symptoms of diarrhea or toxic megacolon combined with a positive result of a laboratory assay and/or endoscopic or histopathologic evidence of pseudomembranous colitis. Recurrent CDAD was defined as repeated episodes within 8 weeks of each other. Severe CDAD was defined by CDAD-associated admission to an intensive care unit, colectomy, or death within 30 days after onset. Case patients were categorized by the setting in which C. difficile was likely acquired, to account for recent evidence that suggests that healthcare facility-associated CDAD may have its onset in the community up to 4 weeks after discharge. Tracking of healthcare facility-onset, healthcare facility-associated CDAD is the minimum surveillance required for healthcare settings; tracking of community-onset, healthcare facility-associated CDAD should be performed only in conjunction with tracking of healthcare facility-onset, healthcare facility-associated CDAD. Community-associated CDAD was defined by symptom onset more than 12 weeks after the last discharge from a healthcare facility. Rates of both healthcare facility-onset, healthcare facility-associated CDAD and community-onset, healthcare facility-associated CDAD should be expressed as case patients per 10,000 patient-days; rates of community-associated CDAD should be expressed as case patients per 100,000 person-years.

Meta-analysis of probiotics for the prevention of antibiotic associated diarrhea and the treatment of Clostridium difficile disease

CONTEXT

Antibiotic-associated diarrhea (AAD) is a common complication of most antibiotics and Clostridium difficile disease (CDD), which also is incited by antibiotics, is a leading cause of nosocomial outbreaks of diarrhea and colitis. The use of probiotics for these two related diseases remains controversial.

OBJECTIVE

To compare the efficacy of probiotics for the prevention of AAD and the treatment of CDD based on the published randomized, controlled clinical trials.

DATA SOURCES

PubMed, Medline, Google Scholar, NIH registry of clinical trials, metaRegister, and Cochrane Central Register of Controlled Trials were searched from 1977 to 2005, unrestricted by language. Secondary searches of reference lists, authors, reviews, commentaries, associated diseases, books, and meeting abstracts.

STUDY SELECTION

Trials were included in which specific probiotics given to either prevent or treat the diseases of interest. Trials were required to be randomized, controlled, blinded efficacy trials in humans published in peer-reviewed journals. Trials that were excluded were pre-clinical, safety, Phase 1 studies in volunteers, reviews, duplicate reports, trials of unspecified probiotics, trials of prebiotics, not the disease being studied, or inconsistent outcome measures. Thirty-one of 180 screened studies (totally 3,164 subjects) met the inclusion and exclusion criteria.

DATA EXTRACTION

One reviewer identified studies and abstracted data on sample size, population characteristics, treatments, and outcomes.

DATA SYNTHESIS

From 25 randomized controlled trials (RCTs), probiotics significantly reduced the relative risk of AAD (RR = 0.43, 95% CI 0.31, 0.58, p < 0.001). From six randomized trials, probiotics had significant efficacy for CDD (RR = 0.59, 95% CI 0.41, 0.85, p = 0.005).

CONCLUSION

A variety of different types of probiotics show promise as effective therapies for these two diseases. Using meta-analyses, three types of probiotics (Saccharomyces boulardii, Lactobacillus rhamnosus GG, and probiotic mixtures) significantly reduced the development of antibiotic-associated diarrhea. Only S. boulardii was effective for CDD.

Risk factors for acquisition of Clostridium difficile-associated diarrhea among outpatients at a cancer hospital

BACKGROUND

Clostridium difficile-associated diarrhea (CDAD) is an important infection in hospital settings. Its impact on outpatient care has not been well defined.

OBJECTIVE

To examine risk factors of ambulatory cancer patients with CDAD.

DESIGN

Case-control study.

SETTING

Memorial Sloan-Kettering Cancer Center, a tertiary-care hospital.

METHODS

Cases of CDAD among oncology outpatients from January 1999 through December 2000 were'identified via positive C. difficile toxin assay results on stool specimens sent from clinics or the emergency department. A 1:3 matched case-control study examined exposures associated with CDAD.

RESULTS

Forty-eight episodes of CDAD were identified in cancer outpatients. The mean age was 51 years; 44% were female. Forty-one (85%) had received antibiotics within 60 days of diagnosis, completing courses a median of 16.5 days prior to diagnosis. Case-patients received longer courses of first-generation cephalosporins (4.8 vs 3.2 days; P = .03) and fluoroquinolones (23.6 vs 8 days; P < .01) than did control-patients. Those receiving clindamycin were 3.9-fold more likely to develop CDAD (P < .01). For each additional day of clindamycin or third-generation cephalosporin exposure, patients were 1.29- and 1.26-fold more likely to develop CDAD (P < .01 and .04, respectively). The 38 CDAD patients hospitalized during the risk period (79.2%) spent more time as inpatients than did control-patients (19.3 vs 9.7 days; P < .001).

CONCLUSIONS

Antibiotic use, especially with cephalosporins and clindamycin, and prolonged hospitalization contributed to the development of CDAD. Outpatient CDAD appears to be most strongly related to inpatient exposures; reasons for the delayed development of symptoms are unknown.

Clindamycin in dentistry: More than just effective prophylaxis for endocarditis?

Clindamycin is a broad-spectrum antibiotic with activity against aerobic, anaerobic, and beta-lactamase-producing pathogens. This antibiotic has been used for many years as prophylactic treatment during dental procedures to prevent endocarditis. However, the spectrum and susceptibility of the bacteria species involved in dental infections indicate that clindamycin would also be an effective treatment option for these conditions. In addition to its antiinfective properties, clindamycin has high oral absorption, significant tissue penetration, including penetration into bone, and stimulatory effects on the host immune system. This review discusses the microbiologic and clinical evidence supporting the efficacy and safety of clindamycin for the successful management of dental infections.

Specific risk factors for Clostridium difficile-associated diarrhea: a prospective, multicenter, case control evaluation

BACKGROUND

Clostridium difficile is a toxin-producing bacterium that is responsible for toxicity to the colonic mucosa, causing inflammation, necrosis, and, in some extreme cases, intestinal dilation and perforation. C difficile-associated diarrhea (CDAD) occurs when patients have a reduction in their natural gastrointestinal flora that allows for the proliferation of and toxin production by C difficile.

METHODS

Using a multicenter, prospective observational case control study, we assessed and quantified risk factors associated with the development of diarrhea caused by Clostridium difficile, with particular attention to antibiotic use. All hospitalized patients with diarrhea requiring a C difficile toxin test as part of their routine clinical workup were considered for study inclusion. Patients with a negative specimen (controls) were considered for enrollment if matched (by age, sex, length of stay, and institution) to a case. Variables associated with CDAD were identified using univariate analysis. Significant factors were then entered into multivariate logistic regression analysis to identify independent factors.

RESULTS

There were no significant differences in antibiotic use between cases and controls. Patient severity, classified by Horn's Index, was significantly different between cases and controls (P = .0022). No other significant variables were identified.

CONCLUSION

The severity of illness of the cases was classified as more severe than the controls, but no significant differences in antibiotic use were identified between the groups. The negative C difficile toxin studies on the well-matched control patients indicate a different etiology of diarrhea (such as antibiotic-associated diarrhea), which may have developed in the presence of similar antibiotic use as the cases.

Antibiotic-associated diarrhea in a Turkish outpatient population: investigation of 288 cases

Oral antibiotics are often prescribed, especially for respiratory tract infections in the community. The widespread use of broad-spectrum antibiotics causes an increased incidence of antibiotic-associated diarrhea (AAD). Although AAD has been studied in hospitalized patients, there is little available information concerning the characteristics of AAD in outpatient populations. The aim of this study was to investigate the clinical and laboratory findings of adult patients with community-acquired AAD. Between June 1998 and December 2003, the clinical reports of 288 patients were retrospectively reviewed. We observed that the duration between the start of antibiotic treatment and onset of symptoms was 7 days in most of the patients (86%), and the mean time was 9+/-1.0 days. The diarrhea was self-limited in all cases and mean duration of symptoms was 3 (+/-1.0) days (1-7 days). The most common symptoms were abdominal discomfort and tenesmus (61.1%), while elevated WBC counts and fever were detected rarely. We were able to perform microbiologic investigations in only 88 patients because of the financial problems. Of the 88 stool specimens tested, none of them were positive for pathogenic bacterial growth or toxin A production.

Antibiotic-associated diarrhea and pseudomembranous colitis: are they less common with poorly absorbed antimicrobials?

Diarrhea is a well-known complication of antibiotic therapy. Rates of antibiotic-associated diarrhea (AAD) vary from 5 to 25%. Some antibiotics are more likely to cause diarrhea than others, specifically, those that are broad spectrum and those that target anaerobic flora. This paper reviews the effects of antibiotics on the fecal flora as well as host factors which contribute to AAD. Clinical features and treatment of AAD are also described. Prevention of AAD rests on wise antibiotic policies, the use of probiotics and prevention of acquisition in the hospital setting. Data from clinical trials suggest that poorly absorbed antimicrobials might have a decreased risk of causing AAD and Clostridium difficile-associated disease, as concluded from studies of antibiotics used for preoperative bowel decontamination and poorly absorbed antibiotics used for traveler's diarrhea. Controlled trials would prove this but are not yet available. Probiotics may be a good adjunct to poorly absorbed antibiotics to minimize the risk of diarrhea associated with antibiotics.

Clostridium difficile: an update

Clostridium difficile causes a spectrum of diarrheal illness with the potential for major medical consequences. Although most cases respond quickly to treatment, C. difficile colitis may be severe and life threatening. Recurrent disease represents a particularly challenging problem.

Molecular epidemiology of hospital-associated and community-acquired Clostridium difficile infection in a Swedish county

All episodes of Clostridium difficile associated diarrhea (CDAD) diagnosed in a defined population of 274,000 including one tertiary and two primary hospitals and their catchment areas were studied during 12 months. The annual CDAD incidence in the county was 97 primary episodes per 100,000, and 78% of all episodes were classified as hospital associated with a mean incidence of 5.3 (range, 1.4 to 6.5) primary episodes per 1,000 admissions. The incidence among hospitalized individuals was 1,300-fold higher than that in the community (33,700 versus 25 primary episodes per 100,000 persons per year), reflecting a 37-fold difference in antibiotic consumption (477 versus 13 defined daily doses [DDD]/1,000 persons/day) and other risk factors. Three tertiary hospital wards with the highest incidence (13 to 36 per 1,000) had CDAD patients of high age (median age of 80 years versus 70 years for other wards, P < 0.001), long hospital stay (up to 25 days versus 4 days), or a high antibiotic consumption rate (up to 2,427 versus 421 DDD/1,000 bed days). PCR ribotyping of C. difficile isolates available from 330 of 372 CDAD episodes indicated nosocomial acquisition of the strain in 17 to 27% of hospital-associated cases, depending on the time interval between index and secondary cases allowed (2 months or up to 12 months), and only 10% of recurrences were due to a new strain of C. difficile (apparent reinfection). In other words, most primary and recurring episodes were apparently caused by the patient's endogenous strain rather than by one of hospital origin. Typing also indicated that a majority of C. difficile strains belonged to international serotypes, and the distribution of types was similar within and outside hospitals and in primary and relapsing CDAD. However, type SE17 was an exception, comprising 22% of hospital isolates compared to 6% of community isolates (P = 0.008) and causing many minor clusters and a silent nosocomial outbreak including 36 to 44% of the CDAD episodes in the three high-incidence wards.

Clostridium difficile-associated diarrhea in adults

Clostridium difficile is the most important cause of nosocomial diarrhea in adults. Illness may range from mild watery diarrhea to life-threatening colitis. An antecedent disruption of the normal colonic flora followed by exposure to a toxigenic strain of C. difficile are necessary first steps in the pathogenesis of disease. Diagnosis is based primarily on the detection of C. difficile toxin A or toxin B. First-line treatment is with oral metronidazole therapy. Treatment with oral vancomycin therapy should be reserved for patients who have contraindications or intolerance to metronidazole or who fail to respond to first-line therapy.

Detection of Clostridium difficile cytotoxin and Clostridium perfringens enterotoxin in cases of diarrhoea in the community

Faecal specimens from 843 cases of diarrhoea in the community were tested for the presence of Clostridium difficile cytotoxin and Clostridium perfringens enterotoxin. C. difficile cytotoxin was detected in faecal specimens from 0.6 % of cases aged at least 2 years by using a Vero cell assay. Factors associated with detection of C. difficile cytotoxin were antibiotic therapy, age over 60 years and living in a home with other elderly people. Three methods were used for the detection of C. perfringens enterotoxin: a Vero cell assay, a commercial (TechLab) enzyme immunoassay (EIA) and an in-house EIA. The lower level of detection of pure C. perfringens enterotoxin in buffer was 0.01 micro g ml(-1) by the TechLab EIA and 1.0 micro g ml(-1) by the Vero cell assay. C. perfringens enterotoxin was detected by using the TechLab EIA in faecal specimens from 2.5 % of cases. This commercial EIA was less sensitive than the in-house EIA, detecting only 31 % of positive cases, but was specific and could be used for outbreak investigation by routine diagnostic laboratories. Age over 60 years was a factor associated with C. perfringens enterotoxin detection; this age group may be targeted for testing.

Incidence and risk factors of oral antibiotic-associated diarrhea in an outpatient pediatric population

BACKGROUND

Little information is available on the epidemiologic characteristics of antibiotic-associated diarrhea (AAD) in children. The authors' aim was to evaluate the incidence of AAD in an outpatient pediatric population and to identify risk factors.

METHODS

Children aged 1 month to 15.4 years treated with oral antibiotics for a proven or suspected infection were enrolled from an ambulatory pediatric practice during an 11-month period. Parents recorded the daily frequency and characteristics of stools using a diary during the antibiotic treatment and for 1 week after it was stopped. An episode of diarrhea was defined by at least 3 soft or liquid stools/d for at least 2 consecutive days. Risk factors for AAD-age, type of antibiotic treatment, type of combined treatment, and site of infection-were analyzed.

RESULTS

Of 650 children included, 11% had an episode of AAD, lasting a mean of 4.0 +/- 3.0 days, beginning a mean of 5.3 +/- 3.5 days after the start of antibiotic treatment. No child was hospitalized because of AAD. The incidence of AAD was higher in children less than 2 years (18%) than in those more than 2 years (3%; P < 0.0001). The incidence of AAD was particularly high after administration of certain antibiotics (amoxicillin/clavulanate, 23%; P = 0.003 compared with other antibiotics). The type of combined treatment and site of infection did not influence the onset of AAD.

CONCLUSIONS

Antibiotic-associated diarrhea was common in these outpatient children, especially for those aged less than 2 years and after the prescription of certain antibiotics, particularly, the combination of amoxicillin/clavulanate.

Antibiotic-associated diarrhoea and Clostridium difficile in the community

BACKGROUND

Clostridium difficile is the main cause of nosocomial infectious diarrhoea and the causative agent of antibiotic-associated colitis. The involvement of C. difficile infection in antibiotic-associated diarrhoea in the community is poorly documented.

METHODS

We studied prospectively 266 adult out-patients in the Paris (France) area who were prescribed a 5-10-day course of antimicrobial chemotherapy. Stools were screened for C. difficile before and 14 days after the start of treatment by standard culture, toxigenic culture and testing for the cytopathic effect of toxin B. Patients were requested to note daily stool frequency and consistency. Diarrhoea was defined as the passage of at least three loose stools per day.

RESULTS

Forty-six (17.5%) of the 262 assessable patients had diarrhoea during the study period. Diarrhoea was mild and self-limited in all patients, and lasted for only 1 day in 65.6% of cases. C. difficile was isolated before and after treatment from one patient, who did not develop diarrhoea. C. difficile was detected only on day 14 in 10 patients (3.8%). The isolate was toxin producing in seven patients. Four of these seven patients had mild self-limited diarrhoea. Toxin-producing C. difficile was isolated significantly more frequently from patients who had diarrhoea than from those who were diarrhoea free (8.7% vs. 1.4%, P = 0.02).

CONCLUSION

The acquisition of toxin-producing C. difficile appears to be frequent during antimicrobial chemotherapy in the community [estimated rate of 2700 (1150-5400) cases per 100 000 exposures to antibiotics]. However, C. difficile is not the main agent of mild antibiotic-associated diarrhoea in out-patients.

Adjunctive intracolonic vancomycin for severe Clostridium difficile colitis: case series and review of the literature

Successful treatment of severe Clostridium difficile colitis has been reported with the use of adjunctive intracolonic vancomycin (ICV) therapy. We report a descriptive case series and review the literature on patients with C. difficile colitis who received adjunctive ICV therapy. Nine patients received antibiotics within 6 weeks prior to presentation. Complete resolution of the clinical presentation occurred in 8 patients (88.9%), and eradication of C. difficile cytotoxin production was documented in 3 (75%) of 4 patients who were tested after the completion of adjunctive ICV therapy. One patient (11.1%) died as a result of progressive multisystem organ failure. In the 6 weeks after the completion of treatment for C. difficile colitis, no patient had recurrent disease, required surgical intervention, or experienced complications from adjunctive ICV therapy. In this case series, administration of adjunctive ICV therapy appeared to be a safe, practical, and effective adjunctive therapy for severe C. difficile colitis.

Biotherapeutic agents in the treatment of infectious diarrhea

Biotherapeutic agents offer unique advantages over traditional treatments for infectious diarrhea, and several have been shown to be effective (Table 4). These therapeutic microbial agents are most effective in types of infectious diseases that are associated with a disruption of the normal intestinal microecology (e.g., AAD, C. difficile disease). The impact of biotherapeutic agents on rotaviral diarrhea is of special clinical importance because this is the most common cause of pediatric diarrhea, and there is no defined treatment. Strong efforts need to be made to limit antibiotic exposure in children. Biotherapeutic agents offer a safe and effective nonantibiotic method of treating this important pathogen, especially after the withdrawal of a rotaviral vaccine from the market by the FDA. However, for many biotherapeutic agents, well-done, placebo-controlled trials still are lacking, and not all types of infectious diarrhea respond to these agents. Continued research in this innovative therapeutic area is warranted.