Rhodococcus equi infection in transplant recipients: a case of mistaken identity and review of the literature.

The incidence of Rhodococcus equi infection in solid-organ transplant recipients continues to rise throughout the world. Unfortunately, this opportunistic pathogen is still underestimated and potentially disregarded by physicians and microbiology laboratories due to its morphology on Gram staining. Pulmonary involvement is the most common finding in the immunocompromised host. We report a case of a 63-year-old heart-transplant recipient who presented with increasing fatigue and nonproductive cough for 3 weeks. After full evaluation, a lung abscess was demonstrated by thoracic computerized tomography (CT). Blood and sputum cultures were remarkable for heavy "diphtheroids." Although the Gram-stain result was initially interpreted as a contaminant, a clinical suspicion for Rhodococcus assisted in further investigation. Broncheoalveolar lavage and CT-guided biopsy of the lung abscess revealed heavy growth of diphtheroids. However, further evaluation by a reference laboratory demonstrated mycolic acid staining consistent with R. equi. Surgical drainage and prolonged antibiotic therapy resulted in complete remission of the pneumonia and abscess. This represents the fourth reported case of R. equi infection in a heart transplant recipient. It is imperative that all physicians and laboratory staff consider R. equi when an immunocompromised patient has any type of pneumonia, especially with abscess formation.

Prevention of primary cytomegalovirus disease in organ transplant recipients with oral ganciclovir or oral acyclovir prophylaxis.

BACKGROUND: Optimal prophylaxis against cytomegalovirus (CMV) disease for organ transplant patients at risk for primary infection (donor seropositive, recipient seronegative, D+R-) remains to be determined. We hypothesized that prolonged oral ganciclovir therapy following intravenous therapy would provide increased protection. METHODS: A total of 155 evaluable D+R- organ transplant recipients from 13 transplant centers were entered into the study: all received intravenous ganciclovir (5 mg/kg/day) for 5-10 days and then either oral acyclovir (400 mg tid) or oral ganciclovir (1 g tid) for an additional 12 weeks. Patients were assigned to their treatment groups at a central randomization site, with a separate randomization scheme for each of the organs transplanted (kidney, heart, or liver). In the case of kidney transplants, the patients were stratified according to source of the kidney (living related vs. cadaveric donor). The primary endpoint was the incidence of CMV disease in the first six months post-transplant. RESULTS: Treatment with oral ganciclovir was associated with a significant decrease in the incidence of symptomatic disease or viremia when compared with the oral acyclovir group (32% vs. 50%, P<0.05). This difference was most marked in terms of tissue invasive disease: only 3 of 15 symptomatic patients in the ganciclovir group vs. 10 of 21 in the acyclovir group developed tissue-invasive infection (P<0.05). There was a significant difference in the time to CMV disease or viremia in the two groups: mean time 212+/-17 days post-transplant for the acyclovir group vs. 291+/-13 days for the ganciclovir group (P<0.001). The incidence of allograft rejection was 34% in the ganciclovir group and 46% in the acyclovir group (P=NS). Leukopenia was more common in the ganciclovir group (P<0.05), but in no case did it require drug discontinuation. Ganciclovir resistance did not develop in this study. CONCLUSION: Prophylaxis with oral ganciclovir following a brief course of intravenous ganciclovir provides useful protection against primary CMV disease.

Influenza update 2000.

Between 30,000-40,000 Americans die annually as a result of influenza epidemics. Spread primarily through the respiratory tract, influenza's classic signs and symptoms are the abrupt onset of fever, myalgia, headache, sore throat, malaise, and nonproductive cough. The elderly and patients with underlying medical illnesses may be at risk for secondary complications. Influenza is caused by an RNA myxovirus that exists in types A, B, and C; however, the A and B types are responsible for most human illness. The Centers for Disease Control and Prevention tracks the viruses' regular pathway through the US each year as they emerge first in Alaska and spread through the lower 48 states, peaking in activity during the winter months. Influenza is preventable by vaccination (efficacy 70%, depending on individual immune status) and is recommended for everyone at increased risk of complications from influenza between 6 months and 50 years of age, and universally for those over the age of 50. The composition of the vaccine has been changed for 2000-2001 to include two new type-A strains and one new type-B. Currently four drugs are available for the treatment of influenza. Early diagnosis can help reduce the inappropriate use of antibiotics and provide the option of using antiviral therapy. Bacterial infections can have similar symptoms or be complications of influenza and should be suspected and treated appropriately if present.

First report of invasive amebiasis in an organ transplant recipient.

T-cell mediated immunity is an important defense mechanism against amebiasis. However, organ transplant recipients with severe T-cell immunosuppression are not at increased risk of having Entamoeba histolytica invasive disease. The reasons are unclear and probably multifactorial, but it is likely that the absence of intestinal colonization with pathogenic strains in countries where transplants occur and the judicious intake of possible contaminated food and water are important contributing factors. We describe the first report of a liver transplant recipient with severe E. histolytica colitis who was successfully treated with metronidazole without modifying his immunosuppression therapy.

Comparison of the amplified Mycobacterium tuberculosis (MTB) direct test, Amplicor MTB PCR, and IS6110-PCR for detection of MTB in respiratory specimens.

Several nucleic acid amplification techniques (NAAT) have been developed for rapid and direct detection of Mycobacterium tuberculosis (MTB) from clinical specimens. This study compared the performances of the Gen-Probe Amplified MTB Direct Test (AMDT), Roche Amplicor MTB PCR test, and an IS6110-PCR assay with acid-fast smear and culture in the detection of MTB from 428 respiratory specimens from 259 patients. Patients' charts were reviewed for clinical correlation. Of 98 specimens that were clinically positive for MTB, acid-fast smear was positive in 50% of cases, culture in 93%, IS6110-PCR in 83%, AMDT in 84%, and Amplicor MTB PCR in 80%. Of 337 specimens that were negative for MTB, 117 (35%) were positive for nontuberculous mycobacteria. Specificities were as follows: smear, 89%; culture, 100%; IS6110-PCR, 99%; AMDT, 98%; and Amplicor MTB PCR, 96%. The accuracies of the tests were 80%, 98%, 96%, and 92%, respectively. MTB culture-positive specimens that were smear-negative were detected by AMDT and IS6110-PCR in 77% of cases and by Amplicor MTB PCR in 70%. NAAT was less sensitive than was culture for detection of MTB, but all these techniques had acceptable accuracy and were completed within hours. NAAT may be useful for rapid screening of respiratory specimens to distinguish MTB from nontuberculous mycobacteria infection in order to isolate patients.

Sepsis due to coryneform group A-4 in an immunocompromised host.

Corynebacteria are more commonly being recognized as significant human pathogens. We describe a case of Coryneform group A-4 sepsis secondary to infection of a Hickman catheter in an immunocompromised man; the organism was identified by biochemical analysis conducted at the Louisiana State Reference Laboratory.

Vibrio vulnificus sepsis in solid organ transplantation: a medical nemesis.

We report two cases of Vibrio vulnificus wound infection leading to fulminant sepsis syndrome in immunocompromised solid organ transplant recipients. Features of clinical presentation in each of these cases suggest that host immune factors are of great importance in the virulence of this organism and that immunocompromised recipients of solid organ transplants are particularly vulnerable to life-threatening consequences from infection with Vibrio vulnificus. Prompt institution of antibiotic therapy and early consideration for surgical wound debridement are the mainstay of successful management. Heart and other organ transplant recipients should be educated and warned about the hazards associated with raw oysters and shellfish consumption and asked to exercise caution when exposed to a salt water environment.

Dermatologic manifestations of infections in diabetics.

In patients with diabetes, the cutaneous signs of the infections that occur are multiple. A high index of suspicion for infection must be maintained while caring for the diabetic patient. Early recognition and prompt treatment will hopefully prevent some of the devastating outcomes that are seen in this group of patients.