Risk factors for Clostridium difficile-associated diarrhoea in HIV-infected patients

Probiotics are effective at preventing Clostridium difficile-associated diarrhea: a systematic review and meta-analysis

INTRODUCTION

Clostridium difficile infection (CDI) is the leading cause of antibiotic-associated diarrhea. CDI has increased in incidence and severity over the past decade, and is a growing worldwide health problem associated with substantial health care costs and significant morbidity and mortality. This meta-analysis examines the impact of probiotics on the incidence of Clostridium difficile-associated diarrhea (CDAD) among children and adults, in both hospital and outpatient settings.

METHODS

A comprehensive literature search of all published randomized control trials (RCTs) assessing the use of probiotics in the prevention of CDAD in patients receiving antibiotic therapy was conducted, and the incidence of CDAD was analyzed.

RESULTS

Twenty-six RCTs involving 7,957 patients were analyzed. Probiotic use significantly reduced the risk of developing CDAD by 60.5% (relative risk [RR] =0.395; 95% confidence interval [CI], 0.294-0.531; P<0.001). Probiotics proved beneficial in both adults and children (59.5% and 65.9% reduction), especially among hospitalized patients. Lactobacillus, Saccharomyces, and a mixture of probiotics were all beneficial in reducing the risk of developing CDAD (63.7%, 58.5%, and 58.2% reduction).

CONCLUSION

Probiotic supplementation is associated with a significant reduction in the risk of developing CDAD in patients receiving antibiotics. Additional studies are required to determine the optimal dose and strain of probiotic.

Clostridium difficile infection among hospitalized HIV-infected individuals: epidemiology and risk factors: results from a case-control study (2002-2013)

Background

HIV infection is a risk factor for Clostridium difficile infection (CDI) yet the immune deficiency predisposing to CDI is not well understood, despite an increasing incidence of CDI among such individuals. We aimed to estimate the incidence and to evaluate the risk factors of CDI among an HIV cohort in Italy.

Methods

We conducted a retrospective case-control (1:2) study. Clinical records of HIV inpatients admitted to the National Institute for Infectious Disease “L. Spallanzani”, Rome, were reviewed (2002-2013). Cases: HIV inpatients with HO-HCFA CDI, and controls: HIV inpatients without CDI, were matched by gender and age. Logistic regression was used to identify risk factors associated with CDI.

Results

We found 79 CDI episodes (5.1 per 1000 HIV hospital admissions, 3.4 per 10000 HIV patient-days). The mean age of cases was 46 years. At univariate analysis factors associated with CDI included: antimycobacterial drug exposure, treatment for Pneumocystis pneumonia, acid suppressant exposure, previous hospitalization, antibiotic exposure, low CD4 cell count, high Charlson score, low creatinine, low albumin and low gammaglobulin level. Using multivariate analysis, lower gammaglobulin level and low serum albumin at admission were independently associated with CDI among HIV-infected patients.

Conclusions

Low gammaglobulin and low albumin levels at admission are associated with an increased risk of developing CDI. A deficiency in humoral immunity appears to play a major role in the development of CDI. The potential protective role of albumin warrants further investigation.

Risk Factors forClostridium difficileInfection in a Hepatology Ward

During 2001,Clostridium difficileinfection was observed in 23 patients hospitalized in a hepatology ward (attack rate, 0.9%). Since strain typing ruled out a clonal dissemination, we performed a case-control study. In addition to antibiotic use as a risk factor, theC. difficileinfection rate was higher among patients with autoimmune hepatitis (P< .01).

Clostridium difficile in a HIV-infected cohort: incidence, risk factors, and clinical outcomes

OBJECTIVE

Clostridium difficile is the most commonly reported infectious diarrhoea in HIV-infected patients in the United States. We set out to determine the incidence, risk factors and clinical presentation of C. difficile infections (CDIs) in a cohort of HIV-infected individuals.

DESIGN

We performed a nested, case-control analysis with four non-CDI controls randomly selected for each case.

METHODS

We assessed the incidence of CDI in the Johns Hopkins HIV Clinical Cohort between 1 July 2003 and 31 December 2010. Incident cases were defined as first positive C. difficile cytotoxin assay or PCR for toxin B gene. We used conditional logistic regression models to assess risk factors for CDI. We abstracted data on the clinical presentation and outcomes from case chart review.

RESULTS

We identified 154 incident CDI cases for an incidence of 8.3 cases per 1000 patient years. No unique clinical features of HIV-associated CDI were identified. In multivariate analysis, risk of CDI was independently increased for CD4 cell count of 50 cells/μl or less [adjusted odds ratio (AOR) 20.7, 95% confidence interval (CI) 2.8-151.4], hospital onset CDI (AOR 26.7, 95% CI 3.1-231.2) and use of clindamycin (AOR 27.6, 95% CI 2.2-339.4), fluoroquinolones (AOR 4.5, 95% CI 1.2-17.5), macrolides (AOR 6.3, 95% CI 1.8-22.1), gastric acid suppressants (AOR 3.1, 95% CI 1.4-6.9) or immunosuppressive agents (AOR 6.8, 95% CI 1.2-39.6).

CONCLUSION

The incidence of CDI in HIV-infected patients was twice that previously reported. Our data show that compromised cellular immunity, as defined by CD4 cell count of 50 cells/μl or less, is a risk factor for CDI. Clinicians should be aware of the increased CDI risk, particularly in those with severe CD4 cell count suppression.

Clostridium difficile infection in HIV-seropositive individuals and transplant recipients

Immunocompromise is a commonly cited risk factor for Clostridium difficile infection (CDI). We reviewed the experimental and epidemiological literature on CDI in three immunocompromised groups, HIV-seropositive individuals, haematopoietic stem cell or bone marrow transplant recipients and solid organ transplant recipients. All three groups have varying degrees of impairment of humoral immunity, a major factor influencing the outcome of CDI. Soluble HIV proteins such as nef and immunosuppressive agents such as cyclosporin, azathioprine and mycophenalate mofetil modify signalling from the key cellular pathways triggered by C. difficile toxin A, although there is a paucity of data on how these factors may interact with pathways activated by toxin B. Despite this, there has been little direct investigation into the effect of immunosuppression on the pathogenesis of CDI. Epidemiological studies consistently show increased rates of CDI in these populations, which are higher in those with greater degrees of immunocompromise such as individuals with advanced AIDS not receiving combination antiretroviral therapy or allogeneic haematopoietic stem cell transplant recipients. Less consistently data suggests immunocompromise in each group also impacts rates of severe, recurrent or complicated CDI. However all these conditions are characterised by high levels of antibiotic use and prolonged hospital stay, both powerful drivers of CDI risk.

Proposed changes to management of lower respiratory tract infections in response to the Clostridium difficile epidemic

Clostridium difficile infection (CDI) remains a major healthcare problem associated with antibiotic use in hospitals. Recent years have seen a dramatic increase in the incidence of CDI in the UK and internationally. Lower respiratory tract infections (LRTIs) are the leading indication for antibiotic prescription in hospitals and are therefore a critical battleground in the fight against inappropriate antibiotic use and healthcare-associated infections. This article reviews the evidence for interventions to reduce CDI in hospitalized patients with LRTIs. Reducing prescriptions of cephalosporins and fluoroquinolones in favour of penicillin-based regimens and increased use of tetracyclines have been proposed. Expanding outpatient management of LRTIs and reducing length of hospital stay will limit patient exposure to the healthcare environment in which C. difficile is most easily acquired. Intravenous (iv) broad-spectrum antibiotics are often prescribed when narrower spectrum, oral antimicrobials would be equally effective and, in a proportion of patients, antibiotic therapy is used unnecessarily. Shorter antibiotic regimes may be as effective as prolonged therapy and reduce antibiotic-related complications. Early switch from iv to oral therapy allows simpler antibiotic regimens and facilitates early discharge from hospital. Simple improvements in the management of LRTIs have the potential to reduce the incidence of healthcare-associated infections.

Gastrointestinal manifestations in patients with acquired immunodeficiency syndrome

Gastrointestinal (GI) involvement is common in patients with acquired immunodeficiency syndrome; however, opportunistic disorders are generally not seen until the CD4 count falls below 200 cells/μl. Although any part of the gastrointestinal tract can be affected, the most common parts involved are the oesophagus and colon. Common oesophageal manifestations are dysphagia and odynophagia, caused by organisms such as Candida and cytomegalovirus (CMV). Common infectious and opportunistic disorders affecting the colon are Salmonella, Shigella, Campylobacter and CMV, which can result in diarrhoea, rectal bleeding and abdominal pain. Endoscopy is the preferred invasive procedure to diagnose most GI diseases. The main advantages of endoscopy are direct visualization of the entire GI tract, the option to obtain mucosal biopsy (which is often necessary to establish a specific diagnosis), and the ability to perform endoscopic therapy (e.g. injection of bleeding vessels). Therapy is based on the individual organism demonstrated.

Bacterial diarrhea in persons with HIV infection, United States, 1992-2002

BACKGROUND

To describe trends in bacterial diarrhea among human immunodeficiency virus (HIV)-infected persons during 1992-2002, we examined data from a longitudinal record review study of persons with HIV infection who were receiving medical care in >100 medical facilities in 9 major United States cities.

METHODS

An analysis was performed using data from 44,778 persons who were followed up for a mean of 2.6 years. We calculated incidence rates and rate ratios for bacterial diarrhea, by stage of HIV disease, and determined odds ratios (ORs) to compare bacterial diarrhea diagnosis in 2002 versus 1992.

RESULTS

The mean annual incidence of bacterial diarrhea was 7.2 cases per 1000 person-years. The incidence of Clostridium difficile-associated diarrhea, the most common bacterial cause of diarrhea, was 4.1 cases per 1000 person-years. Compared with persons without AIDS, persons with AIDS were more likely to have bacterial diarrhea (incidence rate ratio, 1.3-9.9, varying by clinical versus immunologic AIDS and type of bacterial diarrhea). Between 1992 and 2002, the overall rate of bacterial diarrhea in persons with clinical AIDS decreased (OR, 0.4; 95% confidence interval, 0.2-0.6). During the same period, bacterial diarrhea rates among other persons in the analysis did not significantly change.

CONCLUSIONS

C. difficile is the most common recognized cause of bacterial diarrhea among persons infected with HIV. The risk for bacterial diarrhea increases with increased severity of HIV disease. Health care professionals should be aware that patients with AIDS are at increased risk for bacterial diarrhea, and they should reinforce recommendations for decreasing the chances of acquiring bacterial diarrhea.

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.

[Risk factors for nosocomial Clostridium difficile diarrhoea in an infectious and tropical diseases department]

FOREWORD

Clostridium difficile associated diarrhea (CDAD) accounts for 25% of all cases of diarrhea occurring in hospital. Infectious diseases departments are considered as presenting with an important risk of CDAD because of the large quantity of antibiotics used.

OBJECTIVES AND METHOD

The authors made a prospective study in the first 6 months of 2001, in order to identify the risk factors of CDAD in their department. One hundred and fifty-two patients hospitalized for at least 6 days were included in this study. The studied factors were: age, mean number of days of hospitalization (MDH), antibiotic therapy, WHO scale of reduced mobility of patients, recent hospitalization (less than 3 months before).

RESULTS

MDH was 36 (IC95%: 23-48). Beta-lactam antibiotics were found as significant risk factors, as reported in the literature. However, age and a recent hospitalization were not related to the CDAD as described in the literature. A reduced mobility of patients was identified as a significant risk factor for developing a CDAD in our department.

Epidemiology and outcome of Clostridium difficile infection and diarrhea in HIV infected inpatients

Clostridium difficile causes diarrhea in HIV infected patients but reports of prevalence, risk factors, and outcome vary. We studied the impact of C. difficile in 161 HIV infected inpatients admitted to Cook County Hospital. Patients with C. difficile had more hospital admissions in the previous 6 months (p =.04), spent more days in the hospital in the previous 3 months (p =.02), more often had previously received H2 blockers or treatment for Pneumocystis carinii (p <.05), and had a more frequent history of herpesvirus (p =.03) or opportunistic infections (p =.04). C. difficile associated diarrhea (CDAD) was the etiology in 32% of all study patients with diarrhea. Patients with CDAD were hospitalized for longer periods (p =.02) and received more antibiotics (p =.002). C. difficile was frequently present in our HIV infected patients, especially those with advanced HIV disease, but appeared to have little impact on morbidity or mortality.

Epidemiology of Clostridium difficile-associated infections

Clostridium difficile is responsible for 15-25% of cases of antibiotic-associated diarrhea (AAD) and for virtually all cases of antibiotic-associated pseudomembranous colitis (PMC). This anaerobic bacterium has been identified as the leading cause of nosocomial infectious diarrhea in adults and can be responsible for large outbreaks. Nosocomial C. difficile infection results in an increased length of stay in hospital ranging from 8 to 21 days. Risk factors for C. difficile-associated diarrhea include antimicrobial therapy, older age (>65 years), antineoplastic chemotherapy and length of hospital stay. Other interventions with high risk associations are enemas, nasogastric tubes, gastrointestinal surgery and antiperistaltic drugs. Prospective studies have shown that nosocomial transmission of C. difficile is frequent but often remains asymptomatic. Patients can be contaminated from environmental surfaces, shared instrumentation, hospital personnel hands and infected roommates. Once an outbreak starts, C. difficile may be spread rapidly throughout the hospital environment where spores may persist for months. Measures that are effective in reducing incidence of C. difficile infections and cross-infection include: (i) an accurate and rapid diagnosis, (ii) appropriate treatment, (iii) implementation of enteric precautions for symptomatic patients, (iv) reinforcement of hand-washing, (v) daily environmental disinfection, and (vi) a restrictive antibiotic policy. C. difficile is a common cause of infectious diarrhea and should be therefore systematically investigated in patients with nosocomial diarrhea.

Medical diagnoses and procedures associated with clostridium difficile colitis

OBJECTIVES

The aim of this study was to examine the associations of Clostridium difficile colitis with other comorbid conditions and procedural interventions among hospitalized patients.

METHODS

The Patient Treatment File of the Department of Veterans Affairs contains the computerized records of all inpatients treated in 172 Veterans Affairs hospitals distributed throughout the United States. The computerized medical records of 15,091 cases with C. difficile colitis and 61,931 controls without the diagnosis were extracted from the annual files between 1993 and 1998. In a multivariable logistic regression, the occurrence of C. difficile colitis served as outcome variable, whereas the occurrences of other diagnoses or procedures served as predictor variables.

RESULTS

The total numbers of diagnoses in the case and control group were 136,840 and 465,972, respectively. The numbers of procedures were 75,479 and 129,612, respectively. C. difficile colitis was significantly associated with HIV infection, candidiasis, malignant neoplasm and chemotherapy, malnutrition, pneumonia, aspiration pneumonitis, intestinal obstruction, diverticulitis, renal failure, urinary tract infection, decubitus, and osteomyelitis. Interventional procedures involving the respiratory tract, bone marrow biopsy, arterial and venous catheterization, urinary catheterization, dialysis, gastrostomy tube, and physical therapy were also frequently associated with the development of C. difficile colitis.

CONCLUSIONS

These associations reflect the influence of causal relationships (such as the use of antibiotics and chemotherapy), an increased risk of exposure to C. difficile among immobilized bedridden patients with chronic disease states, or a general system failure in patients with end-stage disease. Knowledge of such associations could help to alert physicians to an increased risk of C. difficile colitis among particular groups of susceptible patients.

Emerging concepts in gastrointestinal aspects of HIV-1 pathogenesis and management

GASTROENTROLOGY 2001;120:607-621

Clostridium difficile-associated diarrhea in a VA medical center: clustering of cases, association with antibiotic usage, and impact on HIV-infected patients

A case-control study of patients with stools assayed for Clostridium difficile toxin over a 24-month period at a Veterans Affairs hospital found that the majority of cases (70.6%) occurred in temporal clusters. Clustering was particularly evident on a designated human immunodeficiency virus (HIV) unit. Thirty-four (75.5%) of 45 HIV-infected patients with C difficile-associated diarrhea (CDAD) died during their hospitalization. Third-generation cephalosporins were the antibiotics most strongly associated with CDAD.

The changing etiology of chronic diarrhea in HIV-infected patients with CD4 cell counts less than 200 cells/mm3

PURPOSE

The purpose of this study was to evaluate the incidence and causes of chronic diarrhea in patients with AIDS over a period of time that included the pre-HAART (highly active antiretroviral therapy) era and the introduction of HAART.

METHODS

The study cohort was comprised of patients receiving primary care at a university-associated outpatient HIV clinic from January 1, 1995 to December 31, 1997. Patients were identified retrospectively through a clinical database and were included in the study if their diarrhea had persisted for longer than two weeks and their CD4 cell count at time of symptoms was <200 cells/mm3. Further data were obtained by chart review.

RESULTS

Over the 36-month period, the occurrence of chronic diarrhea did not change significantly, ranging from 8 to 10.5% per year in patients with CD4 cell counts <200 cells/mm3. The percentage of patients diagnosed with opportunistic infectious etiologies decreased over the three-year period from 53% (1995) to 13% (1997). The percentage of patients diagnosed with noninfectious causes increased from 32% to 70% over this same time period.

CONCLUSIONS

Over the three years of the study, the incidence of chronic diarrhea in AIDS patients in our clinic did not change. The etiologies of diarrhea did change significantly, with an increased incidence of noninfectious causes and a decreased incidence of opportunistic infectious causes. This shift in etiologies coincides with the introduction and increased use of HAART in our clinic population (1996).

Nosocomial infections in patients with HIV disease

Throughout the AIDS epidemic, nosocomial infection in the patient with HIV disease has presented a constant problem--not only for the hospitalized patient but also for the clinic attender. The nosocomial spread of multidrug-resistant tuberculosis has emphasized the need for effective control of infection measures in dealing with the immunodeficient. Increased recognition of nosocomial bacterial pneumonias has raised questions about the place, if any, of antimicrobial prophylaxis in preventing Gram-negative and Legionella infection. The use of long-term indwelling venous catheters for the administration of parenteral therapy is associated with an increased risk of nosocomial bloodstream infection--particularly from staphylococci and Pseudomonas spp. Evidence now exists for the nosocomial spread of opportunistic infections, including Cryptosporidium parvum, Mycobacterium avium complex and Pneumocystis carinii. The delay between exposure and diagnosis, the atypical presentation of infections such as tuberculosis and repeated hospital admissions of AIDS patients can combine to confuse the issue with the result that a nosocomial infection may be mis-classified as community-acquired. It seems likely that the burden of nosocomial infection in HIV disease is continually underestimated.

Diagnosis and treatment of colonic disease in AIDS

The colon is a frequent site of gastrointestinal complications in patients with HIV infection, and these colonic disorders increase in frequency as immunodeficiency worsens. The most common clinical manifestations of colonic disease in AIDS are diarrhea, lower gastrointestinal bleeding, and abdominal pain. Toxic megacolon, intussuseption, typhlitis, idiopathic colonic ulcer, and pneumatosis intestinalis also have been described. In the HIV-infected patient with preserved immunity, the most common cause of colitis is bacterial, but as the degree of immunodeficiency worsens, opportunistic pathogens (CMV, protozoa, mycobacteria, fungi) and neoplasms become more frequent. The frequent use of antibiotics, chemotherapeutic agents, and frequent hospitalization increase the susceptibility to cf2Clostridium difficule cf1colitis. Endoscopy plays an integral role in the management of many colonic disorders in AIDS.

Risk factors for Clostridium difficile infection

A systematic review of the literature to identify risk factors associated with Clostridium difficile infection was conducted. Two main outcomes were considered: C. difficile diarrhoea and C. difficile carriage. A qualitative assessment, based on a set of defined and consistently applied criteria, appeared to be the best approach for risk factors other than antibiotic use, as an approach based on meta-analysis would have utilized only the information provided by a minority of the studies. Risk factors for which there was evidence suggestive or consistent with an association with C. difficile diarrhoea were: increasing age (excluding infancy), severity of underlying diseases, non-surgical gastrointestinal procedures, presence of a nasogastric tube, anti-ulcer medications, stay on ITU, duration of hospital stay, duration of antibiotic course, administration of multiple antibiotics. For malignant haematological disorders there was evidence of an association only with C. difficile carriage, but there were no suitable studies to explore a possible association of this risk factor with symptomatic infection. Antibiotic use lent itself to quantitative assessment with meta-analysis using logistic regression. Exposure to an antibiotic was shown to be statistically significantly associated with both C. difficile diarrhoea and C. difficile carriage. The meta-analysis approach enabled the ranking of individual antibiotics in relation to the risk of C. difficile infection, though the 95% confidence intervals were often wide and overlapping. Antibiotics associated with a lower risk of C. difficile diarrhoea should be considered, especially when attempting to control a C. difficile outbreak or when prescribing for a patient with other C. difficile risk factors. This systematic review of the literature enabled the identification of features it would be desirable to consider in future epidemiological studies.

Low rate of Clostridium difficile colonization in ambulatory and hospitalized HIV-infected patients in a hospital unit: a prospective survey

OBJECTIVE

To determine the frequency of Clostridium difficile carriage in HIV-infected in- and out-patients, and to assess the role of this carriage in nosocomial transmission of C. difficile.

PATIENTS AND METHODS

Prospective study in a university hospital. Forty-five consecutive HIV-infected out-patients and 120 hospitalized patients (52 HIV and 68 non HIV-infected-patients) were studied. During the period of hospitalization, 44 patients (24 HIV and 20 non-HIV-infected patients) with a negative culture within 48 h of admission were followed weekly for fecal carriage. Clostridium difficile culture and latex agglutination were performed on the fecal samples of each patient. In the case of positive culture and/or latex agglutination, C. difficile toxin assays were performed by microtitre cytotoxicity method.

RESULTS

Out-patients: one patient was a carrier and one patient with diarrhoea was infected with a toxigenic strain (2/45, 4.5%, 95% CI = 1-17). Eighty percent of the HIV-infected out-patients had received antimicrobial agents previously. In-patients: in the first 48 h, five asymptomatic patients were carriers (three non-HIV and two HIV-infected patients). Among 20 patients who complained of diarrhoea, one HIV-infected patient had only a positive latex agglutination and one HIV-infected patient was infected with a toxigenic strain. Overall, 7/120 (5.8%, 95% CI = 2-10) patients were infected or colonized with C. difficile. During the hospitalization (743 patient-days), none of the 44 patients acquired C. difficile.

CONCLUSION

This study suggests that in this given unit, C. difficile carriage is low, at least with single room accommodation, and in the absence of clusters of cases. This carriage is not different in HIV and non-HIV infected patients despite treatment with multiple antibiotics, and is not different in patients managed in different care environments. The systematic identification of C. difficile carriers for isolation and prophylactic treatment is not useful under these circumstances.

Clostridium difficile-associated diarrhea in HIV-infected patients: epidemiology and risk factors

A retrospective analysis of all the cases of Clostridium difficile-associated diarrhea (CDAD) in hospitalized patients infected with HIV was performed over a 52-month period to assess the incidence, epidemiology, and risk factors of CDAD. A case of CDAD was defined as a patient with diarrhea and a positive stool cytotoxin B assay. Sixty-seven cases of CDAD were recorded in HIV-infected patients between January 1991 and April 1995. The annual incidence of CDAD ranged from 1.7 to 6.4 per 100 HIV-infected patients discharged from hospital. The 67 CDAD cases included 48 (72%) first episodes and 19 (28%) relapses. Serogroup C accounted for 69% of strains from initial episodes of CDAD. To identify risk factors for CDAD, 34 HIV-infected patients with a first episode were compared with 66 HIV-infected controls matched for the length of hospital stay. Three independent factors remained significantly associated with CDAD among HIV-infected patients: CD4+ cell counts <50/mm3 (OR = 5.2; 95% CI = 1.4-19.3; p = 0.01), clindamycin use (OR = 5.0; 95% CI = 1.3-18.3; p = 0.02) and penicillin use (OR = 4.6; 95% CI = 1.1-18.8; p = 0.03). C. difficile is a common enteric pathogen responsible for nosocomial diarrhea in HIV-infected patients. Clinicians should keep this pathogen in mind when searching for the cause of diarrhea in these patients, especially those who are severely immunocompromised or have received clindamycin or penicillin.

Review article: the therapy of gastrointestinal infections associated with the acquired immunodeficiency syndrome

Although there have been dramatic strides in the therapy of human immunodeficiency virus infection over the last few years, the number of infected people world-wide is tremendous and, at least in developing countries, continues to expand. Complications which involve the gastrointestinal tract are common in these patients, because the gut is a major site for involvement by opportunistic infections and neoplasms in patients with the acquired immunodeficiency syndrome. It is important to recognize the clinical spectrum of gastrointestinal diseases, as well as the appropriate and most cost-effective diagnostic strategies, as therapies for a number of these disorders are both widely available and high effective. This review summarizes the major gastrointestinal infections which are seen in patients with the acquired immunodeficiency syndrome, and their treatment.

Agents of diarrhea

Diarrhea is a common problem for AIDS patients, and is chronic and debilitating. A thorough evaluation will reveal a pathogen in the majority of patients, and the organisms most frequently identified in AIDS patients with chronic diarrhea are Cryptosporidium, microsporidia, and Mycobacterium avium complex. Bacterial pathogens are more common in AIDS patients than in the general population and may present in different ways from infections in immunocompetent hosts. Other pathogens, including Cryptosporidium and microsporidia, are difficult to diagnose and have no effective therapy. Moreover, enteric viruses and HIV itself may contribute to the diarrhea. In addition to microbes, other factors such as medication, immune dysregulation, automatic dysfunction, and nutritional supplementation play a substantial role in diarrhea of AIDS patients.

Nosocomial colonization and infection in persons infected with human immunodeficiency virus

Nosocomial infections appear to be increased in patients with acquired immunodeficiency syndrome (AIDS), compared to individuals with asymptomatic infection due to human immunodeficiency virus (HIV). Risk factors for bacterial colonization and infection include immunosuppression, prior treatment with some antibiotics, increased hospitalizations with longer lengths of stay, greater exposure to invasive devices such as indwelling intravenous or urinary catheters, and the degree of immunosuppression. Data suggest that other infectious agents such as Pneumocystis carinii, Mycobacterium tuberculosis, Mycobacterium avium complex, and Cryptosporidium may be acquired in healthcare facilities. Diagnosis and management of nosocomial infections in HIV-infected persons may be complicated by an atypical presentation, increased rates of relapse following treatment, presence of multiple infections, and early discharge from the inpatient setting. Accurate assessment of nosocomial infections and outbreaks in the hospital is complicated by limited data on the risk of transmission of both traditional and unusual pathogens in this population. Furthermore, some patients may acquire nosocomial pathogens during their initial hospitalization and present later with infections that normally would be classified as community acquired. Therefore, there probably is an underestimation of current nosocomial infection rates, and perhaps "hospital-associated" or "healthcare-facility-associated" might be more accurate terms for these infections.

Clostridium difficile infection

The spore-forming anaerobe Clostridium difficile has become a serious enteropathogen. Changes in the composition of natural intestinal flora, mainly due to antibiotic therapy, permit its colonization of, and multiplication in, the colon. The disease is caused by (entero)toxin A and (cyto)toxin B, and infection ranges from asymptomatic carrier state and mild diarrhea to pseudomembranous colitis. The clinical diagnosis is made by observing inflammatory, sometimes bloody, diarrhea and by the colonoscopic detection of epithelial necrosis, ulceration, and, in the advanced state, pseudomembrane formation. The laboratory supports the diagnosis by detecting toxin A and/or B by an enzyme-linked immunoassay with high specificity, but sometimes less sensitivity than with the cytotoxin assay in tissue culture cells. Fecal leukocytes or fecal lactoferrin may be found. Culture for the isolation and identification of toxigenic C. difficile is time consuming but necessary for epidemiological studies. Polymerase chain reaction (PCR) tests have been tested for detection of the toxin B gene directly in stool. Therapy consists of stopping all systemic antibiotic treatment and the use of oral metronidazole or vancomycin. There may be more relapses after vancomycin therapy, and the increasing vancomycin resistance of Enterococcus is worrisome. Prevention, especially of nosocomial spread, requires isolation and enforced handwashing. For epidemiological studies, the bacteria can be typed by molecular DNA analyses, including PCR, protein electrophoresis, and immunological tests.