Mycobacterium tuberculosis infection and laboratory diagnosis in solid-organ transplant recipients

Tuberculosis (TB) is an unusual infection in transplant recipients. We evaluated (i) the frequency of TB, (ii) the duration to develop the TB infection, and (iii) clinical consequences, in 380 solid-organ recipients from January 1995 to December 2000. A total of 10 (2.63%) patients (eight renal, two liver transplant recipients) were found to have post-transplantation TB. The frequency of TB in this patient population is 8.5-fold higher than the prevalance in the general Turkish population. Tuberculosis developed within 2-33 months after transplantation, with a median of 15 months. In all of these 10 patients, Mycobacterium tuberculosis (MTB) was isolated from the culture. All the patients continued to have low dose immunosuppressive treatment, and also quadriple antituberculosis treatment [isoniazid (INH), rifampin (RIF), pyrazinamide (PRZ) and ethambutol (ETB)] has been given. The two recipients had died of disseminated form of TB. Relapse was detected in one patient 6 months after the completion of the treatment. As post-transplant TB infection develops mostly within the first year after transplantation, clinicians should be more careful for early and fast diagnosis and treatment should be started immediately.     

Diagnosis and treatment of latent tuberculosis infection in liver transplant recipients in an endemic area

BACKGROUND: Treatment of latent tuberculosis infection (LTBI) with isoniazid is recommended for transplant recipients with positive tuberculin skin test (TST). However, TST could be an imperfect identifier of LTBI in this population. In addition, the risk of isoniazid hepatotoxicity could be high in liver transplant recipients (LTR). A retrospective cohort study was performed to evaluate the diagnosis and treatment of LTBI in LTR. METHODS: Charts of all 547 patients who received primary liver transplantation at a University Hospital in Spain between 1988 and 1998 were reviewed. RESULTS: TST was performed in 373 patients (71%) before transplantation. The result was positive in 89 (24%). The median follow-up after transplantation was 49 months. None of the TST-positive patients developed tuberculosis (TB), but 5 out of 284 patients with negative TST (1.76%) had active TB (P=0.6). Twenty-three patients received isoniazid as treatment of LTBI according to the decision of the attending physician. None of these patients developed TB, but 4 of them (17%) presented isoniazid hepatotoxicity. Among patients who did not receive isoniazid, 2 out of 21 (9.52%) with radiologic previous TB developed active TB versus 0.44% (2/452) among the remaining patients (relative risk [RR], 27.8, 95% CI, 3.2-147). CONCLUSIONS: Treatment of LTBI with isoniazid can not be recommended to LTR on the basis of a positive TST because it is an imperfect identifier of patients at risk of TB. LTR with radiologic features of previous TB are at higher risk of posttransplant active TB. Isoniazid-related hepatotoxicity is more frequent among LTR than in the general population.     

Tuberculosis in Iranian kidney transplant recipients: a single-center experience

INTRODUCTION: Renal transplantation recipients are at a high risk of developing tuberculosis (TB) following transplantation, especially in developing countries, with high incidences of morbidity and mortality. In this report, we examined the risk factors and impact of TB on the outcome of kidney transplantation. PATIENTS AND METHODS: Among 1350 living donor Iranian kidney transplantations, 52 (3.9%) had TB diagnosed in various organs. Of these, 7 (13.5%) had TB pretransplantation and 40 (76.9%) were men. The overall mean age was 32.6 +/- 10.5 years. RESULTS: The interval between transplantation and diagnosis was 54.6 +/- 48.23 (range 4 to 140) months. In 34 (65.6%) patients TB was diagnosed after the first year posttransplantation. Pleuro/pulmonary TB was the most common form (68%). All posttransplant TB patients received a quadriple antituberculosis therapy; pyrazinamide, rifampicin, ethambutol, and isoniazide). Hepatotoxicity was seen in 16 (30%) patients, including 12 mild cases with normalization after temporary withdrawal of isoniazide and rifampicin, and four were severe, but mortality was not attributable to hepatocellular failure. Twelve patients (23%) died. Chronic allograft dysfunction occurred in 34 (65%) patients, 19 (37%) with graft loss. Pre-TB patients showed comparable posttransplant courses. CONCLUSION: TB is a common infection among renal transplant recipients in developing countries. The peak incidence is after the first year of transplantation and mortality is considerable. Hepatoxicity is a considerable risk of treatment, possibly as a result of additive toxic effects of immunosuppressive drugs. Chronic allograft nephropathy is a serious complication that has a negative impact on the graft survival.     

Tuberculosis of the lumbar spine: outcomes after combined treatment of two-drug therapy and surgery

This article evaluates complications and treatment results in patients with tuberculosis of the lumbar spine. Eighteen patients with active tuberculosis of the lumbar spine were treated surgically in the orthopedic surgery department at Uludag University School of Medicine between 1993 and 2000. All patients received antituberculosis combination drug therapy (isoniazid and rifampicin) for 9 months. Patients who underwent anterior radical debridement and anterior fusion and/or posterolateral debridement and posterior fusion plus stabilization showed 5-8 degrees correction of local angulation after surgery. The mean loss of correction at final follow-up (mean: 5 years) in anterior or posterior surgery alone was 45%-50%, whereas the corresponding finding for the combined approach was 12%. The combination of two-drug chemotherapy (daily isoniazid and rifampicin for 9 months) and surgery is effective for tuberculosis of the lumbar spine.     

Successful Liver Transplantation in Antituberculosis Therapy-Induced Acute Fulminant Hepatic Failure

The antituberculosis drugs isoniazid, rifampin, and pyrazinamide expose patients to the risk of hepatotoxicity ranging from an asymptomatic increase in aminotransferase concentrations to fulminant hepatic failure. Herein, we report a case of acute fulminant hepatic failure that developed at 3 weeks after initiation of antituberculosis therapy (ATT) in a 31-year-old man with acute pulmonary tuberculosis in whom pretreatment liver function had been normal. The ATT regimen was changed to include less toxic substances, and an urgent orthotopic liver transplantation was performed successfully. Despite immunosuppression therapy with tacrolimus, mycophenolate mofetil, steroids, and antithymocyte globulin, clinical symptoms and radiologic signs of TB improved. Twelve months posttransplantation, graft function was normal. Acute TB should not be considered a contradiction to liver transplantation if effective ATT can be administered.     

Safety and efficacy of isoniazid chemoprophylaxis administered during liver transplant candidacy for the prevention of posttransplant tuberculosis

BACKGROUND: Optimal timing of initiation of isoniazid chemoprophylaxis in liver transplant recipients who test positive on the tuberculin skin test has not been defined. We sought to determine whether isoniazid prophylaxis administered during liver transplant candidacy was safe and effective for the prevention of posttransplantation tuberculosis. METHODS: During a 9-year period, 18 liver transplant candidates with tuberculin skin test greater than 5 mm or recent conversion to positive tuberculin skin test were identified and received isoniazid chemoprophylaxis for 12 months. For each case, a control matched with the patient for underlying liver disease and age (within 5 years of the case) was included. Liver function tests were assessed monthly. The median follow-up was 55 months and ranged up to 107 months for the cases. RESULTS: At baseline, the cases had a total bilirubin of 2.2 mg/dL, alanine aminotransferase of 106 IU/L, prothrombin time of 14.2 sec, and serum albumin of 2.9 gm/dL (mean values). Hepatic function tests did not differ significantly for the cases at 3, 6, 9, and 12 months when compared with those at baseline or between the cases and controls at each of the above time points. Discontinuation of prophylaxis was not required in any of the patients. The outcome (proportion of patients who underwent transplantation or were dead or alive at the last follow-up) and survival time for the cases did not differ significantly from those of the controls (P >0.20). CONCLUSION: In liver transplant candidates at risk for infection after transplantation, isoniazid chemoprophylaxis used during candidacy was well tolerated and did not adversely effect hepatic function or outcome as compared with the control patients.     

Tuberculosis in Renal Transplant Recipients: A Brazilian Center Registry

Renal transplant recipients receiving immunosuppression show an increased risk for developing opportunistic infections, such as tuberculosis (TB). TB represents the major cause of morbidity and mortality in the world, mainly in underdeveloped countries. The aim of this study was to analyze the incidence of TB and its presentation among renal transplant recipients over 20 years.

Patients and Methods

This retrospective analysis included medical records of renal transplant recipients from January 1984 to April 2007.

Results

Among 1342 renal transplant recipients, 31 received treatment for TB due to clinical disease (n = 23) or prophylaxis (n = 8). The overall incidence of TB was 1.71%, which was diagnosed at 53 ± 49 months posttransplantation. The indications for TB prophylaxis were a previous history of TB (n = 6) or direct contact with a TB carrier (n = 1). The most common clinical presentation was extrapulmonary (n = 13). The classical treatment was effective in 16 cases. However, 7 cases of resistant TB required ethambutol added to therapy. Adverse events of treatment included liver toxicity (n = 1) and peripheral neuropathy (n = 1). Three patients died due to TB-related complications. Graft loss was observed in 3 patients after cessation of TB treatment. None of the patients on prophylaxis developed clinical disease.

Conclusions

TB incidence was significantly greater among renal transplant recipients compared with the local population, with a higher incidence of extrapulmonary disease. TB prophylaxis in selected cases was effective, avoiding new infections.     

Tuberculosis after renal transplantation

Tuberculosis (TB) remains a major public health problem in our country. Its diagnosis in immunodeficient patients is difficult. In this retrospective study, we analyzed the prevalence, clinical presentation, and outcome of TB after renal transplantation (RT) in our Tunisian team's experience. Among 359 renal transplant recipients, 9 (2.5%) developed TB at 49.6 months (range, 3-156 months) after RT. There were 7 men and 2 women of mean age 37.8 years (range, 15-53 years). The organs involved included lymph nodes in 1 case; lung in 5 cases; genitourinary system in 1 case; rachis in 1 case; pleural in 1 case; and both pulmonary and urinary systems in 1 case. The diagnosis was bacteriologic in 6 cases; histologic in 1 case; and 2 patients had a high index of suspicion. All patients were treated with a combination of rifampicin, isoniazide, pyrazinamide, and ethambutal. Recurrence of TB infection was noted in 3 cases with multiple localizations: lymph node, muscle abscess, meningitis, genitourinary system, rachis, and lung. Two patients died. In conclusion, among renal transplant patients, extrapulmonary involvement and recurrence of TB were frequent.     

Tuberculosis in Egyptian kidney transplant recipients: study of clinical course and outcome

BACKGROUND: Tuberculosis (TB) is an important infection encountered post-transplantation especially in developing countries, with high incidences of morbidity and mortality. In this report, we study the risk factors and impact of TB on the outcome of kidney transplantation. METHODS: Of 1200 live-donor Egyptian kidney transplantations, 45 (3.8%) patients developed post-transplant TB. Of these, five had had TB pre-transplantation and 40 were male. The mean age was 32.6 +/- 10.5 years. Primary immunosuppression treatment for 39 (86.7%) patients was cyclosporine (CsA). RESULTS: The mean time interval between transplantation and TB diagnosis was 49.8 +/- 41.5 (range 2-180) months. In 86.7% of patients, TB was diagnosed one year post-transplantation. Urinary TB was the most common form (53%), while pleuropulmonary TB accounted for 38%. All post-transplant TB patients received a triple anti-tuberculous therapy (rifampicin, ethambutol and INH) with a favorable response in all but two patients who needed another 24-month course. Hepatotoxicity was seen in 11 patients, eight were mild with normalization after temporary withdrawal of rifampicin, and three cases were severe, but mortality was not attributable to hepatocellular failure. Twelve patients died, 11 of them due to unrelated causes. Chronic rejection occurred in more than half of the patients (55.6%), of whom 24 (96%) were CsA-treated, which can be attributed to rifampicin/CsA interaction. More than 35% of TB patients lost their graft as a result. Pre-transplant tuberculosis patients had a comparable post-transplant course. CONCLUSIONS: TB is a common infection in renal transplant recipients with a peak incidence occurring one year post-transplant. Chronic rejection is a serious complication that had a negative impact on the graft survival, especially in CsA-treated recipients. INH prophylaxis is safe in pre-transplant TB. The post-transplantation outcome in the pre-transplant tuberculosis patients is no different from non-TB patients.     

Fatal primary multidrug-resistant tuberculosis in a heart transplant recipient

The incidence of tuberculosis (TB) worldwide is currently on the rise, not only in the general population but also quite notably among immunosuppressed patients. Its incidence among patients undergoing antirejection therapy is considerably higher than in the general population, and heart transplant recipients have been found to carry the highest risk of TB. There are no reported data, however, on primary TB caused by multidrug-resistant (MDR) Mycobacterium tuberculosis (M. tuberculosis) in heart transplant recipients. We describe the case of a patient who developed active primary MDR TB following the reactivation of a latent tuberculous infection 6 months after transplantation. The patient was most likely infected by M. tuberculosis during a period of time he spent in prison 10 years before undergoing transplantation, but he never developed active tuberculosis, nor did he ever receive antituberculous medication prior to transplantation. Because of the atypical clinical presentation, establishment of the diagnosis was postponed, and the resistance pattern of the isolate grown from bronchoalveolar lavage (BAL) specimens (resistant to isoniazid and rifampicin) led to treatment failure and a fatal outcome. The adoption of the most rapid diagnostic tools for the identification of M. tuberculosis and for a quick screening of drug-resistant isolates is urgently needed in those centers where organ transplantation is carried out. Received: 16 December 1997 Received after revision: 25 February 1998 Accepted: 16 March 1998     

Tuberculosis in southern Chinese renal‐transplant recipients

Abstract: Objectives: To analyze the characteristics of tuberculosis (TB) in Southern Chinese renal transplant recipients, and summarize the corresponding experiences in diagnosis and management. Method: Retrospectively study 41 documented post‐transplant TB cases out of the 2333 patients who received kidney transplantation in the First Affiliated Hospital of Sun Yat‐sen University between Jan. 1991 and Apr. 2007. Results: TB in the post‐renal‐transplant population in Southern China displayed the following characteristics: (i) high incidence within a short time after transplantation, the median interval between renal transplantation and diagnosis of TB was 8 months (range: 1‐156 months) and 56.1% were diagnosed within the first year post‐transplant; (ii) high prevalence (51.2%) of extra‐pulmonary tuberculosis; (iii) high co‐infection rate (19.5%), pathogens included candida albicans, pseudomonas aeruginosa, staphylococcus aureus, Acinetobacter haemolyticus and cytomegalovirus; (iv) fever (82.9%), cough (56.1%) and sputum (39.0%) are the most common clinical manifestations; (v) purified protein derivative of tuberculin (PPD) skin test had little diagnostic value in this group with a negative result in all 41 cases; (vi) acute rejection (29.3%) and liver function damage (17.1%) were the main adverse effects of anti‐tuberculosis chemotherapy; (vii) mortality of patients with post‐transplant tuberculosis reached up to 22.0%. Conclusions: Chinese renal transplant recipients face a high risk of TB because of their immuno‐compromised state and epidemiological prevalence of the disease. Therefore, attention should be given to this differential diagnosis in clinical practice. Balancing the benefits and disadvantages of anti‐tuberculosis chemotherapy is of importance for this specific population.     

Liver transplantation without isoniazid prophylaxis for recipients with a history of tuberculosis

Abstract:  Tuberculosis remains one of the most serious infections after organ transplantation. Isoniazid prophylaxis for liver transplant recipients with a history of tuberculosis is generally recommended. However, its benefit is controversial because of potential hepatotoxicity of isoniazid. It is crucial to determine appropriate post-transplant managements for the recipients with a history of tuberculosis. The purpose of this study was to investigate the necessity of isoniazid prophylaxis for liver transplant recipients who had a history of tuberculosis. The medical records of 1116 liver transplant recipients were studied, of whom seven had a history of tuberculosis (0.63%). One who underwent living-donor liver transplantation for fulminant hepatic failure was excluded from evaluation because of early death, caused by bacterial sepsis two months after transplantation, although reactivation of tuberculosis was not observed. The median observation period after transplantation was 25.5 months (range 12–82). Reactivation of tuberculosis did not occur in any of these six patients. In conclusion, we could not find rationale for isoniazid prophylaxis in liver transplant recipients with past diagnosis of tuberculosis, when the disease is considered to be inactive. Tuberculosis should be considered as cause of post-transplant infections, and careful post-transplant observations are essential for an early diagnosis.     

Efficacy of isoniazid prophylaxis in renal allograft recipients

The efficacy of isoniazid (INH) prophylaxis in renal allograft recipients who are on long-term immunosuppression in a region highly prevalent for tuberculosis (TB) was studied. INH (300 mg/d in patients weighing more than 35 kg and 5 mg/kg/d in patients with <35 kg body weight) together with Pyridoxine 50 mg/d for 1 year was started in randomly assigned renal allograft recipients. Occurrence of clinical tuberculosis during the initial 2 years posttransplantation was observed in the risk group and patients at no risk. Risks were defined as acute rejection episodes and exposure to antirejection therapy, past history of TB completely or incompletely treated, radiological evidence of past tuberculosis, history of tuberculosis in close contacts. Among 480 patients registered in the study, INH prophylaxis was given to 219 randomly assigned renal allograft recipients. Results were compared among patients developing TB during the initial 2 years posttransplantation in both the groups. Risk factors were analyzed for comparison in both groups. No significant difference was observed in terms of past history of TB, TB in close contacts, episodes of acute rejection during the initial 3 months, and comorbidities such as cytomegalovirus infection, hepatitis C virus infection, and posttransplant diabetes. One patient from the INH group and 10 patients from the non-INH group developed TB during the initial 2 years posttransplantation (P < .0001). None of patients required discontinuation of INH. INH was observed to be safe and effective as a chemoprophylactic agent in renal allograft recipients.     

Short-course chemotherapy for tuberculosis of the spine. A comparison between ambulant treatment and radical surgery--ten-year report

We performed a randomised, controlled clinical trial to compare ambulant short-course chemotherapy with anterior spinal fusion plus short-course chemotherapy for spinal tuberculosis without paraplegia. Patients with active disease of vertebral bodies were randomly allocated to one of three regimens: a) radical anterior resection with bone grafting plus six months of daily isoniazid plus rifampicin (Rad6); b) ambulant chemotherapy for six months with daily isoniazid plus rifampicin (Amb6); or c) similar to b) but with chemotherapy for nine months (Amb9). Ten years from the onset of treatment, 90% of 78 Rad6, 94% of 78 Amb6 and 99% of 79 Amb9 patients had a favourable status. Ambulant chemotherapy for a period of six months with daily isoniazid plus rifampicin (Amb6) was an effective treatment for spinal tuberculosis except in patients aged less than 15 years with an initial angle of kyphosis of more than 30 degrees whose kyphosis increased substantially.     

Tuberculosis in Solid Organ Transplant Recipients at a Tertiary Hospital in the Last 20 Years in Barcelona, Spain

Objective

Mycobacterium tuberculosis (TB) is a serious opportunistic infection in solid organ transplant recipients. The TB incidence is 20 to 74 times greater than that among the general population. Our aim was to determine the incidence as well as the clinical, radiological, and microbiological features and outcomes of TB in these patients.

Materials and Methods

We reviewed the clinical records of subjects with posttransplant TB from January 1988 to December 2007. A definite TB case was defined by a positive culture; probable TB by a positive smear or histological finding; and disseminated TB when 2 organs were involved. We noted an early diagnosis as ones in the first year posttransplantation. Outcomes were classified following the WHO recommendation and mortality related defined by death during treatment.

Results

Among 4634 recipients (2757 kidney, 1334 liver, 361 double kidney-pancreas, and 182 heart), 21 (0.45%) developed posttransplant TB: namely, 0.47%, 0.22%, 1.1%, and 0.54%, respectively. In 2 cases M. tuberculosis did not grow upon culture; the diagnosis was established by positive acid-fast bacilli on a sputum smear or by histological findings on biopsy. The mean posttransplantation time to TB diagnosis was 21 months (48% early TB). Two patients had a previous history of TB. Fever was the most common symptom (71%). Pulmonary tuberculosis represented 47.6% of cases; extrapulmonary, 28.6%; and disseminated, 23.8%. Among the cases of pulmonary TB, 60% had unilateral infiltrates and 10% cavitations on X ray. Eighteen patients completed treatment. Five patients displayed adverse events, 3 of which were liver toxicity. Four patients died, with 3 deaths related to TB.

Conclusions

The incidence of TB in this cohort was higher than that among the general population (450 cases/100,000 recipients). TB was associated with adverse effects of treatment and significant mortality.     

Tuberculosis in renal transplant recipients

BACKGROUND: Tuberculosis is an important cause of morbidity and mortality in renal transplant recipients, but there are insufficient data regarding the efficacy and complications of therapy and of INH prophylaxis. METHODS: This study is a retrospective review of the records of 880 renal transplant recipients in two centers in Turkey. RESULTS: Tuberculosis developed in 36 patients (4.1%) at posttransplant 3-111 months, of which 28 were successfully treated. Eight patients (22.2%) died of tuberculosis or complications of anti-tuberculosis therapy. Use of rifampin necessitated a mean of 2-fold increase in the cyclosporine dose, but no allograft rejection occurred due to inadequate cyclosporine levels. Hepatotoxicity developed in eight patients during treatment, two of whom died due to hepatic failure. No risk factor, including age, gender, renal dysfunction, hepatitis C, or past hepatitis B infection, was found to be associated with development of hepatic toxicity. A subgroup of 36 patients with a past history of or radiographic findings suggesting inactive tuberculosis, was considered to be at high risk for developing active disease, of whom 23 were given isoniazid (INH) prophylaxis. None versus 1 of 13 (7.7%) of cases with and without INH prophylaxis, respectively, developed active disease (P>0.05). None of the patients receiving INH had hepatic toxicity or needed modification of cyclosporine dose. CONCLUSIONS: These data show that tuberculosis has a high prevalence in transplant recipients, that it can effectively be treated using rifampin-containing antituberculosis drugs with a close follow-up of serum cyclosporine levels, and that INH prophylaxis is safe but more experience is needed to define the target population.     

Tuberculous meningitis in a renal transplant recipient

Tuberculous meningitis is a very rare, but serious extrapulmonary complication of mycobacterial infections in immunocompromised patients, such as organ transplant recipients. We describe here a 66-year-old Turkish woman without any history of tuberculosis, who received a renal allograft transplant in 1994. After a pilgrimage to an endemic area for tuberculosis, she presented with fever and headache in August 1998. Clinical examination revealed positive meningism and hyperreflexia. Lymphocytosis was noted in her cerebrospinal fluid (CSF) and Mycobacterium tuberculosis infection was detected by PCR within the CSF. Despite immediate triple antituberculosis therapy, the patient's clinical condition deteriorated rapidly, with the development of septic shock syndrome, and she died three weeks after admission due to cardiovascular and respiratory failure. Mycobacterial infections, including extrapulmonary manifestations, should thus be considered in all renal transplant recipients presenting with unexplained fever. Preventive therapy, i.e. isoniazid prophylaxis, may also be recommended for patients risking exposure in areas endemic for tuberculosis.     

Tuberculosis after heart transplantation: twenty years of experience in a single center in Taiwan

The incidence of tuberculosis is slightly higher among heart transplantation cases than in the general population in Taiwan. Tuberculosis shows a high mortality rate ranging from 22% to 31% in transplant recipients. From October 1987 to October 2007, we performed 315 heart transplantations. Clinical records were reviewed for demographic data, clinical presentation, treatment, and outcome. Tuberculosis was diagnosed by cultures of any body sample in association with compatible symptoms and signs. Mortality was related to tuberculosis if there was evidence of active tuberculosis at the time of death and no other etiology accounted for death. Ten patients who had received heart transplants were diagnosed as tuberculosis. There were seven pulmonary lesions and seven extrapulmonary lesions. Treatment consisted of isoniazid, rifampin, ethambutol, pyrazinamide, streptomycin, ciprofloxacin, and levofloxacin. Seven patients completed the antituberculosis treatment: the median treatment duration was 1 year. Three patients developed hepatitis. There was no tuberculosis-related mortality. Ten out of a total of 315 patients (3.17%) represented a tuberculosis rate higher than that reported for the general Taiwan population (67/100,000). This high mortality of infection may be completely treated by a combination of at least three drugs except pyrzinamide because of side effects and tolerance.     

Successful management of two heart transplant recipients with mycobacterial pulmonary infections

We report two cases of pulmonary tuberculosis in heart transplant recipients: a 46-year-old man with pulmonary tuberculosis due to Mycobacterium tuberculosis and a 64-year-old man with nontuberculous mycobacterial infection with pulmonary infiltrates due to Mycobacterium xenopi. The time intervals from transplantation to diagnosis were 3 and 4 years, respectively. The patient with tuberculosis underwent standard treatment with isoniazid, rifampin, ethambutol, and pyrazinamide. The patient with the nontuberculous mycobacterial infection received treatment with clarithromycin and ciprofloxacin for 18 months in addition to rifampin for the first 3 months. Both patients responded well to treatment. No recurrences were observed during follow-up. The interactions between antibiotic treatment and cyclosporine therapy should be observed closely in organ transplant recipients, requiring frequent level determinations and dosing changes.