Cryptosporidium spp. Infection in Adult Kidney Transplant Patients: A Systematic Review and Meta-Analysis

Background: Diarrhea frequently occurs after vascular organ transplantation, including kidney transplants. This may result from non-infectious factors, adverse effects of immunosuppressive medications, or infections caused by various pathogens, including viruses, bacteria, fungi, or parasites, for example, intestinal protozoan parasites such as Cryptosporidium spp., which are particularly dangerous for immunocompromised patients. Methods: This review is based on scientific articles sourced from validated databases such as PubMed, the National Center for Biotechnology Information (NCBI), ScienceDirect, and Google Scholar. The primary search was conducted on 12-13 July 2024, using the keywords 'Cryptosporidium' AND 'cryptosporidiosis' AND 'kidney' AND 'transplant' AND 'adult'. Inclusion criteria encompassed human studies, case reports, peer-reviewed journal publications, review articles, and research articles in English. Exclusion criteria included studies not in English, gray literature (e.g., conference proceedings and abstracts), and data related to pediatric patients (under 18 years old) and HIV patients. Results: This systematic review and meta-analysis have highlighted an often-overlooked connection between Cryptosporidium spp. infections in adult kidney transplant recipients (KTR). Furthermore, it includes an analysis of the clinical presentation, diagnosis, and treatment of Cryptosporidium spp. infection in these patients, based on available case reports. Our study demonstrates that adult kidney transplant patients are at a significantly higher risk of acquiring Cryptosporidium spp. compared to healthy participants. Conclusions:Cryptosporidium spp. infections can be asymptomatic, making it essential to screen both symptomatic and asymptomatic kidney transplant recipients. The clinical presentation of cryptosporidiosis typically involves digestive symptoms and can be complicated by biliary tract involvement. In KTR patients presenting with diarrhea, it is crucial to not only test for Cryptosporidium spp. but also to rule out bacterial and viral etiologies, including infections such as C. difficile, C. colitis, Clostridium spp., and rotavirus. The diagnosis of Cryptosporidium spp. infections primarily relies on microscopic methods, which are known for their low sensitivity. Therefore, diagnostic approaches should include both direct methods and, where possible, molecular techniques. Based on the analyzed cases, the most effective treatment results were achieved with reduction in immunosuppression if possible (strong, very low) and nitazoxanide at a dose of 500 mg twice daily for 14 days. Considering the public health implications of our findings, the current epidemiological data underscore the need for further research to develop effective prevention and intervention strategies against cryptosporidiosis. Preventive measures, regular screening programs, and the treatment of Cryptosporidium spp. infections should be integrated into the clinical care of transplant patients. It is also important that patients are informed about environmental risk factors.

Toxoplasmosis, cryptosporidiosis, and isosporiasis in HIV-negative immunocompromised patients: A single-centre study, Ottawa, Ontario, Canada

BACKGROUND

Historically, patients with HIV have been at the highest risk of infection with opportunistic protozoans such as Toxoplasma, Cryptosporidium, and Isospora. Among patients with HIV who are compliant with antiretroviral therapy, the likelihood of acquiring an opportunistic infection is low. The risk of infection is harder to mitigate in the growing number of HIV-negative immunodeficient patients, such as people with hematological malignancies or those who are post-transplantation.

METHODS

We conducted a retrospective case series of patients with documented Toxoplasma infections between 2008 and 2017 and with Cryptosporidium and Isospora infections between 2014 and 2017 at the Ottawa Hospital.

RESULTS

During the study period, there were 10 confirmed cases of toxoplasmosis, 20 cases of cryptosporidiosis, and 2 cases of isosporiasis. Cryptosporidiosis (95%) and toxoplasmosis (60%) occurred more frequently among HIV-negative patients, whereas isosporiasis cases were limited to HIV-positive patients. Among patients with cryptosporidiosis, the most common underlying cause of immunosuppression in HIV-negative individuals was solid organ transplantation (15.79%), followed by diabetes (10.53%), end-stage renal disease (5.26%), and hematologic malignancy (5.26%). Seventy percent of patients had no known cause of immunosuppression. The most common underlying condition associated with toxoplasmosis was hematological malignancy (50%), followed by solid organ transplantation (33.33%), and solid tumours (16.66%).

CONCLUSIONS

This study's results suggest that Cryptosporidium infections are more common among immunocompetent patients in Ottawa, whereas Toxoplasma infections are more common among HIV-negative patients with acquired immunodeficiencies. As the demographics of immunocompromised individuals continue to evolve, screening for protozoal infections in high-risk populations may become clinically important.

Prevalence of Cryptosporidium Infection in the Global Population: A Systematic Review and Meta-analysis

BACKGROUND

Cryptosporidium is a protozoan parasite that can infect both humans and animals and cause cryptosporidiosis. We aimed to estimate the global prevalence of Cryptosporidium infection.

METHODS

In this study, Web of Science, Medline and PubMed were searched for relative articles, published between January 1, 1960 and January 1, 2018. Included articles were restricted to English language and that sample size of articles was not less than 50. Studies with no information on the study period, location, method of diagnosis, sample size and number of infected people were excluded. Studies about outbreak, laboratory report or immunocompromised population were excluded as well. The quality of the included publications was assessed. The prevalence of cryptosporidiosis was estimated by DerSimonian-Laird random-effects model, after converting by the Freeman-Tukey type double arcsine transformation.

FINDINGS

From 13,064 publications selected by literature search, 221 studies were included in the meta-analysis. The global pooled prevalence of Cryptosporidium infection was 7.6 % (95% CI: 6.9-8.5). The highest estimated prevalence of Cryptosporidium infection was in Mexico (69.6%, 95% CI 66.3-72.8), Nigeria (34.0%, 95% CI 12.4-60.0), Bangladesh (42.5%, 95% CI 36.1-49.0) and Republic of Korea (8.3%, 95% CI 4.4-13.2) among general residents, patients, school children and healthy population, respectively. The estimated prevalence was high in people from low-income country, people with gastrointestinal symptoms, people younger than 5 years old and residents not living in urban areas.

CONCLUSIONS

These estimates indicate the substantial prevalence of Cryptosporidium infection in the world, which may provide a theoretical basis for the formulation of the prevention strategy about Cryptosporidium.

Association between Cryptosporidium infection and cancer: A systematic review and meta-analysis

The link between cryptosporidiosis and cancer has been suggested by some epidemiological studies. This systematic review and meta-analysis was conducted to further understand this relationship. In the current study, six electronic databases were reviewed for Cryptosporidium infection in cancer patients. We used random effects model and 95% confidence intervals (CI) to determine the overall odds ratio (OR). Heterogeneity was calculated with Cochran's Q test and I²statistic. In total, 19 studies involving 3562 individuals with case-control (nine) and cross-sectional (ten) designs were included in our project. The pooled overall random effect favored a statistically significant increased risk of Cryptosporidium infection in cancer patients compared with non-cancer individuals [OR = 3.3; 95% CI: 2.18-4.98]. The overall heterogeneity was medium (χ² = 25.77; I² = 30.2%, P = .11). The pooled ORs in case-control and cross-sectional studies were [OR = 5.60; 95% CI: 3.43-9.13; χ² = 5.51; I² = 0.00%, P = .70] and [OR = 2.08; 95% CI: 1.18-3.67; χ² = 13.69; I² = 34.3, P = .13], respectively. T-value and P-value were 0.54 and 0.57 based on the results of Harbord's modified's regression test. In summary, this meta-analysis demonstrates that Cryptosporidium infection is associated with cancer. Also, it found that study design and year of publication are the specific sources of heterogeneity. Further studies should be carried out to investigate the impact of Cryptosporidium infection in the onset or development of cancer in the future.