Mycobacterium tuberculosis infections after renal transplantation

Screening for Latent Tuberculosis Infection in Solid Organ Transplant Recipients to Predict Active Disease: A Systematic Review and Meta-Analysis of Diagnostic Studies

BACKGROUND

This is a systematic review and meta-analysis of diagnostic test accuracy studies to assess the predictive value of both tuberculin skin test (TST) and interferon-gamma release assays (IGRA) for active tuberculosis (TB) among solid organ transplantation (SOT) recipients.

METHODS

Medline, Embase, and the CENTRAL databases were searched from 1946 until June 30, 2022. Two independent assessors extracted data from studies. Sensitivity analyses were performed to investigate the effect of studies with high or low risk of bias. Methodological quality of each publication was assessed using QUADAS-2.

RESULTS

A total of 43 studies (36 403 patients) with patients who were screened for latent TB infection (LTBI) and who underwent SOT were included: 18 were comparative and 25 noncomparative (19 TST, 6 QuantiFERON-TB Gold In-Tube [QFT-GIT]). For IGRA tests taken together, positive predictive value (PPV) and negative predictive value (NPV) were 1.2% and 99.6%, respectively. For TST, PPV was 2.13% and NPV was 95.5%. Overall, PPV is higher when TB burden is higher, regardless of test type, although still low in absolute terms. Incidence of active TB was similar between studies using LTBI prophylaxis (mean incidence 1.22%; 95% confidence interval [CI], .2179-2.221) and those not using prophylaxis (mean incidence 1.045%; 95% CI, 0.2731-1.817; P = .7717). Strengths of this study include the large number of studies available from multiple different countries; limitations include absence of gold standard for diagnosis of latent TB and low incidence of active TB.

CONCLUSIONS

We found both TST and IGRA had a low PPV and high NPV for the development of active TB posttransplant. Further studies are needed to better understand how to prevent active TB in the SOT population.

Chemoprophylaxis for the prevention of tuberculosis in kidney transplant recipients: A systematic review and meta-analysis

Background: A systematic review and meta-analysis was performed to investigate the efficacy and safety of isoniazid (INH) prophylaxis to prevent tuberculosis (TB) infection in kidney transplant recipients (KTRs).

Methods: Web of Science, SCOPUS, and PubMed were searched to identify relevant studies that compared the effects among patients who received INH prophylaxis after transplantation.

Results: A total of 13 studies (involving 6,547 KTRs) were included in our analysis. We found that the risk of active TB infection (RR: 0.35, 95%CI 0.27–0.45, p < 0.01) for KTRs was lower in the INH treatment group than in those without prophylaxis. However, there was no significant difference between the two groups in mortality (RR: 0.93, 95%CI 0.67–1.28, p = 0.64), acute rejection (RR: 0.82, 95%CI 0.44–1.51, p = 0.52), and hepatotoxicity (RR: 1.25, 95%CI 0.94–1.65, p = 0.12).

Conclusion: Isoniazid prophylaxis is a safe and effective for KTRs on reactivation of latent TB infection.

Mycobacterium Tuberculosis Infection after Kidney Transplantation: A Comprehensive Review

Tuberculosis (TB) in kidney transplant (KT) recipients is an important opportunistic infection with higher incidence and prevalence than in the general population and is associated with important morbidity and mortality. We performed an extensive literature review of articles published between 1 January 2000 and 15 June 2022 to provide an evidence-based review of epidemiology, pathogenesis, diagnosis, treatment and outcomes of TB in KT recipients. We included all studies which reported epidemiological and/or outcome data regarding active TB in KT, and we approached the diagnostic and treatment challenges according to the current guidelines. Prevalence of active TB in KT recipients ranges between 0.3–15.2%. KT recipients with active TB could have a rejection rate up to 55.6%, a rate of graft loss that varies from 2.2% to 66.6% and a mortality rate up to 60%. Understanding the epidemiological risk, risk factors, transmission modalities, diagnosis and treatment challenges is critical for clinicians in providing an appropriate management for KT with TB. Among diagnostic challenges, which are at the same time associated with delay in management, the following should be considered: atypical clinical presentation, association with co-infections, decreased predictive values of screening tests, diverse radiological aspects and particular diagnostic methods. Regarding treatment challenges in KT recipients with TB, drug interactions, drug toxicities and therapeutical adherence must be considered.

Tuberculosis prevention in patients undergoing kidney transplantation: A nurse-led program for screening and treatment

BACKGROUND

Systematic screening for, and treatment of, latent tuberculosis (TB) infection is recommended prior to kidney transplant. However, little is known about patient compliance with, or the safety profile of, preventive therapies used in clinical practice.

METHODS

This was a retrospective observational study of patients who were eligible for kidney transplant and were evaluated for TB infection between January 2013 and June 2019 at the TB clinic of a tertiary care teaching hospital. All patient data were registered prospectively as part of our nurse-led program before kidney transplant. We assessed completion rates, tolerance with therapy, development of TB, and associated workload.

RESULTS

In total, 1568 patients were referred to our TB clinic for evaluation. Preventive therapy was given to 385 patients and completed by 340 (88.3%). Of these, 89 (23.1%) experienced some intolerance, with 27 requiring full discontinuation. After a median follow-up of 45 months (1426 patient-years), 206 (53.5%) of the treated patients received a kidney transplant; only one patient, who failed to complete treatment, developed post-transplant TB (7.01 cases per 10 000 patient-years; 95% confidence interval, 0.35-34.59). Extra nurse or medical visits were required by 268 (69.6%) patients.

CONCLUSION

Despite the complexity and workload generated by patients with ESRD awaiting kidney transplant, preventive therapy for TB is effective in most cases. Our experience provides important evidence on the feasibility of preventive therapy for TB before kidney transplant when delivered as part of a comprehensive nurse-led program.

Prevention and treatment of tuberculosis in solid organ transplant recipients

Introduction: Tuberculosis (TB) in solid organ transplant (SOT) recipients is associated with significant morbidity and mortality. Its management in transplant recipients is difficult and highly complex, given the underlying immunosuppression and the risks of drug-drug interactions imposed by immunosuppressive drugs that are needed to maintain the transplant allograft.Areas covered: We provide a brief review of TB in SOT and discuss the clinical indications, mechanisms of action and drug resistance, drug-drug interactions, and adverse effects of anti-TB drugs. We provide a summary of recent clinical trials, which serve as the foundation for current recommendations. We further include relevant updates on new agents being evaluated for clinical use in TB management.Expert commentary: TB causes significant morbidity in SOT recipients. The drugs used in the treatment for latent TB and active disease in SOT are similar to the regimens used in the general population. However, TB disease in transplant recipients is more difficult to manage because of the potential for hepatotoxicity and the complex drug-drug interactions with immunosuppressive drugs. We believe that alternative regimens suited for the vulnerable transplant population, and more therapeutic drug options are needed given the adverse toxicities associated with currently approved anti-TB drugs.

Prevalence of active tuberculosis infection in transplant recipients: A systematic review and meta-analysis

INTRODUCTION

Tuberculosis (TB) is considered as a serious complication of organ transplant; therefore, the detection and appropriate treatment of active TB infection is highly recommended for the reduction of mortality in the future. The aim of this review was to conduct a systematic review and meta-analysis assessing the prevalence of active TB infection in transplant recipients (TRs).

MATERIAL AND METHODS

Electronic databases, including MEDLINE (via PubMed), SCOPUS and Web of Science were searched up to December 24, 2017. The prevalence of active TB was estimated using the random effects meta-analysis. Heterogeneity was evaluated by subgroup analysis. Data were analyzed by STATA version 14.

RESULTS

The pooled prevalence of post-transplant active TB was estimated 3% [95% CI: 2-3]. The pooled prevalence of active TB in different transplant forms was as follows: renal,3% [95% CI: 2-4]; stem cell transplant (SCT), 1% [95% CI: 0-3]; lung, 4% [95% CI: 2-6]; heart, 3% [95% CI: 2-4]; liver, 1% [95% CI: 1], and hematopoietic stem cell transplant (HSCT), 2% [95% CI: 1-3]. The prevalence of different clinical presentations of TB was as follows: pulmonary TB (59%; 95% CI: 54-65), extra pulmonary TB (27%; 95% CI: 21-33), disseminated TB (15%; 95% CI: 12-19) and miliary TB (8%; 95% CI: 4-13). The pooled prevalence of different diagnostic tests was as follows: chest X-ray, 57% [95% CI, 46-67]; culture, 56% [95% CI, 45-68]; smear, 49% [95% CI, 40-58]; PCR, 43% [95% CI, 40-58]; histology, 26% [95% CI, 20-32], and tuberculin skin test, 19% [95% CI, 10-28].

CONCLUSION

A high suspicion level for TB, the early diagnosis and the prompt initiation of therapy could increase the survival rates among SOT patients. Overall, renal and lung TRs appear to have a higher predisposition for acquiring TB than other type of recipients. Monitoring of the high-risk recipients, prompt diagnosis, and appropriate treatment are required to manage TB infection among TRs especially in endemic areas.

Treatment of latent TB Infection and the risk of tuberculosis after solid organ transplantation: Comprehensive review

BACKGROUND

Mycobacterium tuberculosis disease may occur after treatment of latent TB infection (LTBI). Prompted by a case of reactivation TB disease in a solid organ transplant (SOT) recipient who received LTBI treatment, we reviewed the literature to examine outcomes, adverse effects, resistance, and treatment choices of tuberculosis after LTBI therapy.

METHODS

MEDLINE and Web of Science from inception to 5/2019 were reviewed using key words "latent tuberculosis infection" and "SOT" or "transplantation." The search yielded nine cases, 41 cohort studies and six randomized controlled trials (RCT).

RESULTS

Cohort and RCT demonstrated significant reduction in TB disease among transplanted patients who received LTBI therapy; only 56/2651 (2.1%) SOT patients developed TB after LTBI therapy. Adverse drug reactions occurred in 149/1148 (12.9%) and 73/641 (11.4%) of cohort and RCT patients, respectively. Among liver recipients, 56/266 (21%) developed side effects, of which half (29/56, 51.8%) was INH-related. There was no reported INH resistance.

CONCLUSIONS

Latent TB infection treatment is efficacious in SOT recipients at risk of TB disease. However, tuberculosis may still occur despite LTBI treatment. Hepatotoxicity associated with LTBI therapy is infrequent, although more commonly observed among liver recipients.

Mycobacterium tuberculosis after solid organ transplantation: A review of more than 2000 cases

BACKGROUND

Mycobacterium tuberculosis (TB) is a common pathogen worldwide, and it may cause significant infection after solid organ transplantation (SOT). We reviewed all reported TB cases to provide an update on its epidemiology, clinical presentation, management, and outcome after SOT.

METHODS

MEDLINE, EMBASE, and OVID were reviewed from January 1, 1998, to December 31, 2016, using keywords tuberculosis and solid organ transplant or transplantation.

RESULTS

There were 187 publications reporting 2082 cases of TB among kidney (n = 1719), liver (n = 253), heart (n = 77), lung (n = 25), and kidney-pancreas (n = 8) recipients. Among cohort studies, the median incidence was 2.37% (range, 0.05%-13.27%) overall. Most TB disease was considered reactivation of latent infection, occurring beyond the first year after SOT. Early-onset cases were seen among donor-derived TB cases. Fever was the most common symptom. Radiologic findings were highly variable. Extrapulmonary and disseminated TB occurred 29.84% and 15.96%, respectively. Multidrug-resistant TB was rare. Treatment using 4 or 5 drugs was commonly associated with hepatotoxicity and graft dysfunction. All-cause mortality was 18.84%.

CONCLUSIONS

This large review highlights the complexity of TB after SOT. Reactivation TB, donor-transmitted infection, extrapulmonary involvement, and disseminated disease are common occurrences. Treatment of TB is commonly associated with hepatotoxicity and graft dysfunction.

Tuberculosis After Renal Transplant

Tuberculosis is one of the leading infections after renal transplant, particularly in developing countries where the incidence and prevalence in the general population are high. Diagnosis requires bacteriologic and histologic confirmation. Interactions among the antitubercular drugs and the immunosuppressive agents have to be considered while prescribing, and surveillance for adverse effects is required. Although rare, case reports are available on extrapulmonary tuberculosis in allograft recipients. Here, we present a 25-year-old kidney transplant recipient who was diagnosed with lymph node tuberculosis under uncommon circumstances but who had a good outcome. This case report illustrates the difficulties in diagnosis of tuberculosis, changes in therapeutic protocols, and prognostic factors and highlights the effects of infectious complications with immunosuppressive therapy in this particular patient population.

Tuberculosis following kidney transplantation: report of paediatric case

Recipients of solid organ transplantation are, because of immunosuppressive therapy, at high risk to develop opportunistic infections including tuberculosis (TB). The incidence, clinical manifestations, and optimal diagnostic tests of this disease in this population have not been adequately defined. In this paper, we report a case of 13 year-old boy who developed pulmonary tuberculosis following a second renal transplantation from a deceased donor. The described case points diagnostic difficulties of the tuberculosis disease which are due to insidious and non specific clinical presentation. Also, the treatment is delicate because interaction between immunosuppressive drugs and antituberculosis drugs.

Tuberculosis following kidney transplantation: clinical features and outcome. A French multicentre experience in the last 20 years

BACKGROUND

Kidney transplant recipients are at high risk of opportunistic infection. The aims of this study were to describe the epidemiology, clinical features and prognosis of Tuberculosis (TB) in kidney transplant recipients.

METHODS

Retrospective observational study conducted in 14 French transplant centres involving all cases of TB that occurred in kidney transplant recipients between 1986 and 2006.

RESULTS

Among the 16146 kidney transplantations performed during the study period, 74 (0.45%) developed TB. The country of birth was a highly endemic area for TB in 20 (40.8%) patients. Time from kidney transplantation to TB was 10 months (4-27). Extrapulmonary and disseminated TB accounted for 33 (67.4%) cases. The most common symptoms were fever (71.7%), weight loss (41.3%) and asthenia (39.1%). Coexisting infections were diagnosed in 11 (22.4%) patients. Microbial sensitivity tests revealed no case of multidrug-resistant TB. Haemophagocytic syndrome associated with TB was diagnosed in 5 (10.2%) cases with 60% of mortality (P = 0.0005). Median length of antituberculous therapy was 12 (9.5-12) months. Immunosuppressive therapy was reduced in 22 (44.9%) patients without adverse consequence on the graft. Overall, hospital mortality was 6.1% and 1-year graft survival was 97%.

CONCLUSIONS

Kidney transplantation increases the risk of TB, with a high rate of extrapulmonary disease. Symptoms of infection are often attenuated, leading to delayed diagnosis. Overall prognosis is good but haemophagocytic syndrome is associated with high mortality. Country of birth might be taken into account in the decision of post-transplantation treatment of latent TB.

Tuberculosis in renal transplant recipients: the evidence for prophylaxis

BACKGROUND

Tuberculosis (TB) remains a leading cause of death in endemic countries and is 20 to 70 times more common in renal transplant recipients, where it contributes to both increased morbidity and mortality. This review will focus on the epidemiology of TB in renal transplant recipients and critically appraise the published literature on isoniazid prophylaxis in renal transplantation.

METHODS

A literature search for randomized and nonrandomized studies investigating the use of isoniazid prophylaxis in renal transplant recipients was conducted using Ovid MEDLINE, the Cochrane Library, the Transplant Library, and EMBASE. Relative risks (RRs) with 95% confidence intervals (CIs) are reported. Meta-analysis of the randomized controlled trials (RCTs) was performed with a fixed-effects model.

RESULTS

Eleven relevant studies were identified; six nonrandomized and five RCTs. The nonrandomized studies indicate a reduced risk of TB with isoniazid prophylaxis. The RCTs demonstrated conflicting results, with two studies finding a reduction in TB with prophylaxis and two studies finding no difference. Meta-analysis of the 709 patients from the four RCTs demonstrated a reduced risk of TB with isoniazid prophylaxis (RR, 0.31; 95% CI, 0.19-0.51). No significant difference was found in the incidence of hepatitis (RR, 1.22; 95% CI, 0.91-1.65).

CONCLUSION

Both randomized and nonrandomized studies support the value of isoniazid as TB prophylaxis in renal transplant recipients at risk of active infection. Clinicians should consider prophylaxis in renal transplant recipients in endemic areas or in recipients in nonendemic countries who are at risk. However, the evidence for the benefit of isoniazid prophylaxis in renal transplantation is not robust and there is still a need for a large multicenter trial of isoniazid prophylaxis in kidney transplantation in an endemic area.

Lung and renal transplantation

Renal transplantation is the most common type of solid organ transplantation and kidney transplant recipients are susceptible to pulmonary complications of immunosuppressive therapy, which are a diagnostic and therapeutic challenge.

AIM

To evaluate patients admitted to the Renal Transplant Unit (RTU) of Hospital de S. João with respiratory disease.

SUBJECT AND METHODS

We performed a retrospective study of all patients admitted to RTU with respiratory disease during a period of 12 months.

RESULTS

Thirty-six patients were included. Mean age 55.2 (+/-13.4) years; 61.1% male. Immunosuppressive agents most frequently used were prednisolone and mycophenolate mofetil associated with ciclosporin (38.9%) or tacrolimus (22.2%) or rapamycin (13.9%). Thirty-one patients (86.1%) presented infectious respiratory disease. In this group the main diagnoses were 23 (74.2%) pneumonias, 5 (16.1%) opportunistic infections, 2 (6.5%) tracheobronchitis, and 1 case (3.2%) of lung abscesses. Microbiological agent was identified in 7 cases (22.6%). Five patients (13.9%) presented rapamycin-induced lung disease. Fibreoptic bronchoscopy was performed in 15 patients (41.7%), diagnostic in 10 cases (66.7%). Mean hospital stay was 17.1 (+/-18.5) days and no related death was observed.

CONCLUSION

Respiratory infections were the main complications in these patients. Drug-induced lung disease implies recognition of its features and a rigorous monitoring of drug serum levels. A more invasive diagnostic approach was determinant in the choice of an early and more specific therapy.

Hepatitis C virus, an important risk factor for tuberculosis in immunocompromised: experience with kidney transplantation

Little is known about the role of hepatitis C virus (HCV) infection in the development of tuberculosis (TB) in patients with immunosuppression. We performed a retrospective case-control study (1:4) to investigate by univariate and multivariate logistic regression analysis the importance of HCV infection in the development of TB in a cohort of kidney transplant recipients (KTR). TB was diagnosed in 16 out of 2012 (0.8%) KTR between 1976 and 2004. The percentage of HCV-positive patients was significantly higher in cases than in controls (56.3% vs. 18.8%; P=0.02). By multivariate analysis, the only two independent risk factors associated with the development of TB were the presence of HCV infection (P=0.003; OR=6.5; 95% CI 1.9-23) and serum creatinine over 1.5 mg/dl (P=0.03; OR=4.8; 95% CI 1.1-21). HCV infection and chronic graft dysfunction are important risks factors for TB in KTR.

Prospective randomized control trial of isoniazid chemoprophylaxis during renal replacement therapy

BACKGROUND

Infectious diseases remain among the major morbid events in patients with end-stage renal disease (ESRD) on renal replacement therapy (RRT). In developing countries, tuberculosis (TB) has been found to occur more frequently in these patients than in the general population. Efficacy of isoniazid (INH) chemoprophylaxis has been seen in other situations, such as human immunodeficiency virus infection. However, studies on INH prophylaxis in ESRD patients on RRT are limited.

METHODS

In this prospective randomized controlled trial, from April 2000 to June 2001, a total of 109 ESRD patients registered for renal transplant and accepted for maintenance hemodialysis in our hospital were included and followed up until June 2004 to assess the role of INH prophylaxis in preventing development of TB. At the time of acceptance for hemodialysis, 54 patients were assigned to receive daily INH for 1 year and 55 patients were assigned to the control group. Primary outcome was development of TB. Secondary outcome was INH hepatotoxicity. To evaluate the effect of INH prophylaxis on the development of TB, a Kaplan-Meier survival estimate was used to plot TB-free survival curve and log-rank test was used for comparison.

RESULTS

Overall, TB was diagnosed in 27 patients during RRT, with an incidence of 24.8%. TB developed in 9 (16.7%) patients in the INH group and in 18 (32.7%) patients in the control group. There was a significantly lower incidence of TB in the INH group as compared with the control group. The risk ratio of INH vs. control group for development of TB was 0.40 (95% confidence index [CI], 0.17-0.92; P=0.032). In the INH group 27 (50%) patients and in the control group 17 (30.9%) patients developed some hepatic dysfunction. However, significant hepatitis that required discontinuation of INH developed in only 9 (16.7%) patients in the INH group. Furthermore, significant hepatitis also developed in 6 (10.9%) patients in the control group. The majority of patients with significant hepatitis in both groups (INH as well as control) were subsequently found to be positive for hepatitis B and/or hepatitis C viral infection. Mild hepatitis (which did not require discontinuation of INH) was seen in 18 (33.3%) patients in the INH group and 11 (20%) patients in the control group. Viral hepatitis infection was not found in any of the milder cases of hepatitis in either group.

CONCLUSION

This study shows significant efficacy of INH chemoprophylaxis during RRT in preventing development of TB, when the INH was started during dialysis itself. INH chemoprophylaxis was safe and well tolerated in the majority of patients. However, mild hepatic dysfunction was common, both in the treatment as well as in the control group. As the incidence of viral hepatitis overall was high in our patients on RRT, it is difficult to identify INH-induced hepatitis in this clinical setting.

Cellulitis as a manifestation of miliary tuberculosis in a renal transplant recipient

Cutaneous involvement is an unusual presentation of tuberculosis (TB) and is rarely reported in renal transplant recipients. We describe a 37-year-old renal transplant recipient with disseminated Mycobacterium tuberculosis infection that presented as cellulitis. The organism was isolated from tissue and blood cultures. The patient was treated with quadruple anti-TB therapy for 12 months. Anti-TB therapy led to a complete resolution of TB lesions. We also provide a review of the literature on cutaneous TB in renal transplant recipients. Skin TB in renal transplant recipients usually occurs with nontuberculous mycobacteria. The spectrum of the skin lesions can be quite different and can mimic bacterial infections. Mycobacteriosis should always be included in the differential diagnosis of a skin lesion in renal transplant recipients.

Tuberculosis in renal transplant recipients on various immunosuppressive regimens

BACKGROUND

Mycophenolate mofetil (MMF) and tacrolimus (TAC) are more potent than conventional immunosuppressive drugs, i.e. azathioprine, cyclosporin and prednisolone, and may be associated with an increase in the incidence of infections in the post-transplantation (post-tx) period. The aim of this study was to determine if the use of either or both of MMF and TAC for immunosuppression in renal transplant recipients increases the prevalence or modifies the clinical presentation of tuberculosis (TB), when compared with conventional therapy.

METHODS

The medical records of 443 adult patients who received a kidney transplant between 1994 and 2002 were reviewed retrospectively. Comparisons were made between patients who had conventional immunosuppressive treatments (cyclosporin, azathioprine and prednisolone) or an alternative regimen (including MMF, TAC or both).

RESULTS

We found 20 patients (4.5%) to have post-tx TB. There were 13 cases of TB (age 38.9+/-10.6 years) among 328 patients who received conventional immunosuppressants (group I) (4.0%) and seven cases (age 24.2+/-7.4 years) among 115 (6.1%) who received an alternative immunosuppressive regimen (group II) (P>0.05). The patients in group II were younger than the patients in group I (P = 0.002). A significantly higher number of patients in group II developed TB within the first 6 months post-tx (P = 0.042). However, there was no significant difference between the two groups regarding clinical and radiographic presentations or outcomes.

CONCLUSIONS

Immunosuppression with TAC or MMF is associated with the development of TB earlier in the post-tx period and in younger patients.

Tuberculous infection in southern Chinese renal transplant recipients

A retrospective study of the prevalence and pattern of tuberculosis among renal transplant patients in a single centre in southern China was performed. Twenty-three cases of tuberculosis were diagnosed among 440 patients between January 1991 and December 2002. There were 18 men and five women. The mean age of the patients was 39.3 +/- 13.4 yr. There were 13 living-related and 10 cadaveric renal transplants. The interval between renal transplantation and the development of tuberculosis ranged from 3 to 127 months with a median of 46 months. There were 18 cases of pulmonary tuberculosis, two cases of pulmonary plus laryngeal tuberculosis, two cases of disseminated tuberculosis, and one case of tuberculosis involving the urinary tract. Diagnosis was established by positive culture for Mycobacterium tuberculosis in 21 patients and response to empirical anti-tuberculosis treatment in two patients. The duration of symptoms before the diagnosis of tuberculosis was 27 +/- 12 d. The patients were treated with standard anti-tuberculosis drugs for 11 +/- 3 months. The anti-tuberculosis treatment was in general well-tolerated. Five patients developed transient hepatitis, three patients developed thrombocytopenia and five patients developed gouty arthritis. One patient died 2 months after initiation of anti-tuberculosis therapy. All other patients completed anti-tuberculosis treatment. No recurrence of tuberculosis was observed after a median follow-up of 90 months. We concluded that (i) tuberculosis is prevalent among southern Chinese renal transplant recipients; (ii) high index of suspicion for tuberculosis among renal transplant recipients is warranted to ensure early diagnosis and prompt initiation of treatment; and (iii) treatment with standard anti-tuberculosis drugs for an extended period of time is well-tolerated and is associated with favourable outcome.

Prospective randomised trial of isoniazid prophylaxis in renal transplant recipient

Renal transplantation (RT) recipients are at a high risk of developing tuberculosis (TB) following transplantation. Effectiveness of isoniazid (INH) in preventing TB is well documented in immunocompetent as well as immunocompromised persons. There is paucity of data on role of INH prophylaxis in RT recipients. Thus, a prospective randomised trial of INH in RT recipients was carried out to determine the efficacy of daily INH monotherapy in the prevention of TB in these patients. Patients of end stage renal disease (ESRD) taken for RT formed the subjects of study. Patients with active TB and active hepatitis at the time of RT were excluded from the study. Patients were randomised to receive INH 300 mg with pyridoxine 20 mg daily from the day of RT. The duration of the treatment was planned for 1 year or till the development of TB, which ever was earlier. Between October 1998 and September 2000, 114 RT were done at our hospital. Of these, 24 (21%) patients had active TB at the time of RT and thus were excluded. Patients included were randomised with 1:2 ratio of treatment and control group. Of the 90 patients thus enrolled, 30 were randomised in treatment group and 60 in control group. Of the included patients five patients had very early graft loss (three in treatment and two in control group) within days and thus excluded from the analysis. Three of the 27 (11.1%) patients in treatment group and 15 (25.8%) in control group developed TB (P = 0.10). The risk ratio of (RR) of INH versus control group of TB was 0.36 (95% CI, 0.10-1.32) but the difference was not statistically significant (P = 0.12). Only one patient developed INH induced hepatitis. In conclusion, with INH prophylaxis, there was a trend towards protection from TB, though it was not statistically significant. Further, all patients tolerated INH and hepatotoxicity was not a major problem in this group of patients.

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Mycobacterial infection after renal transplantation in a Western population

Mycobacterial infection is a serious opportunistic infection in renal transplant recipients. The incidence is higher in developing than in developed Western countries. This study is a single-centre retrospective review of the records of 2502 renal transplant recipients in Belgium. Fourteen cases of mycobacterial infection (9 Mycobacterium tuberculosis and 5 atypical mycobacterial infection) were diagnosed. The time interval between transplantation and diagnosis was 64 +/- 80 months (mean +/- SD, range 5-188) for M. tuberculosis and 92 +/- 75 months (range 14-209) for atypical mycobacterial infection. The localisation of M. tuberculosis was pulmonary/pleural in 67% and extrapulmonary in 33%. The atypical mycobacterial infections were located in skin, tendons, and joints. Eight patients received IV prednisolone pulse therapy for acute rejection long before the time of mycobacterial infection. The initial antimycobacterial therapy consisted of a combination of isoniazid, rifampicin, and ethambutol in all patients. In patients with M. tuberculosis infection, a good response to antimycobacterial therapy was obtained. In patients with atypical mycobacterial infection, initial treatment was successful in 3 out of 5 patients, in 1 patient recurrence was diagnosed and in another patient, who is still under treatment at present, the initial treatment was adjusted after identification of the atypical mycobacterium and its antibiogram. The incidence of mycobacterial infection after renal transplantation did not increase with newer immunosuppressive therapy. The major risk factor is the total dose of corticosteroids. All patients responded well without major reductions in immunosuppressive therapy. Chemoprophylaxis for high-risk patients still is recommended.

Posttransplant infections in the tropical countries

Over half of all renal transplant recipients in the tropical countries develop a serious infection at some point in the posttransplant period and 20% to 40% of them succumb to these infections. Many of these infections are endemic to the region. A multitude of factors including unhygienic conditions, hot and humid climate, late presentation, lack of knowledge about the spectrum of organisms in these areas, scanty diagnostic techniques, and high cost of lifesaving antimicrobial agents contribute to this dismal outcome. Tuberculosis is observed in 10% to 15% of transplant recipients. Pleuropulmonary disease is most frequent, but the commonly employed tests are seldom helpful in the diagnosis. Bronchoalveolar lavage is very sensitive in early detection of this infection and allows timely institution of specific therapy. Hepatitis virus infections are generally acquired before transplant, and viral replication is accelerated under the effect of immunosuppressive therapy leading to chronic liver disease. Cytomegalovirus (CMV) disease has shown a fourfold increase after introduction of cyclosporine to the immunosuppressive regimes at our center. Coinfection with other bacteria or fungi is frequent in CMV-infected allograft recipients. Opportunistic fungal infections are seen in less than 10% of allograft recipients, but this figure is likely an underestimate. The frequently encountered fungal infections include Candida, Aspergillus, Cryptococcus, and Mucor. Fungal infections carried a high mortality of over 65% at our center. The protean manifestations of the opportunistic infections and nonavailability of sensitive diagnostic tests in most centers in the underdeveloped countries often delay the diagnosis and institution of therapy.

Urinary tract infections after renal transplantation

Up to now one of the major problems for successful organ transplantation has been the reaction of the immune system of the recipient against the donor organ. This could lead to acute and chronic rejection, and in cases of unsuccessful treatment to the loss of the transplant. In organ graft recipients, immunosuppressive agents are used to prevent or treat rejection episodes and to maintain graft function. Although there is an increasing number of immunosuppressive substances, the immunosuppressive therapy currently in use is relatively unspecific and targets many immunological functions. The net state of immunosuppression is a complex function determined by the interaction of a number of factors, the most important of these are the dose, duration and temporal sequence in which immunosuppressive drugs are employed. Any kind of immunosuppressive protocol is thus associated with an increased infection rate. This has an important socioecological impact, because frequent hospitalizations resulting from infectious complications are necessary, having an overall mortality rate of 3.5% within 2 weeks of admission. The most common cause of septicaemia is urinary tract infection. Frequent urinary tract infections are associated with the early onset of chronic rejection, suggesting a pathogenetic relationship between these two features. The occurrence of chronic rejection has led to reduced transplant survival. The prevention of urinary tract infections, or the early diagnosis and accurate treatment of urinary tract infections is important in renal transplant recipients.