Mark P. Wilhelm

Emergence of a New Pathogenic Ehrlichia Species, Wisconsin and Minnesota, 2009

BACKGROUND Ehrlichiosis is a clinically important, emerging zoonosis. Only Ehrlichia chaffeensis and E. ewingii have been thought to cause ehrlichiosis in humans in the United States. Patients with suspected ehrlichiosis routinely undergo testing to ensure proper diagnosis and to ascertain the cause. METHODS We used molecular methods, culturing, and serologic testing to diagnose and ascertain the cause of cases of ehrlichiosis. RESULTS On testing, four cases of ehrlichiosis in Minnesota or Wisconsin were found not to be from E. chaffeensis or E. ewingii and instead to be caused by a newly discovered ehrlichia species. All patients had fever, malaise, headache, and lymphopenia; three had thrombocytopenia; and two had elevated liver-enzyme levels. All recovered after receiving doxycycline treatment. At least 17 of 697 Ixodes scapularis ticks collected in Minnesota or Wisconsin were positive for the same ehrlichia species on polymerase-chain-reaction testing. Genetic analyses revealed that this new ehrlichia species is closely related to E. muris. CONCLUSIONS We report a new ehrlichia species in Minnesota and Wisconsin and provide supportive clinical, epidemiologic, culture, DNA-sequence, and vector data. Physicians need to be aware of this newly discovered close relative of E. muris to ensure appropriate testing, treatment, and regional surveillance. (Funded by the National Institutes of Health and the Centers for Disease Control and Prevention.).

Emergence of drug‐resistant cytomegalovirus in the era of valganciclovir prophylaxis: therapeutic implications and outcomes

Abstract:  Background:  Valganciclovir prophylaxis is reportedly associated with a low incidence of ganciclovir‐resistant cytomegalovirus (CMV). We assessed the incidence, clinical features, and outcome of drug‐resistant CMV among solid organ transplant patients who received valganciclovir prophylaxis.

Prophylaxis of cytomegalovirus infection in liver transplantation: A randomized trial comparing a combination of ganciclovir and acyclovir to acyclovir

BACKGROUND The optimal prophylactic regimen to prevent cytomegalovirus (CMV) infection and disease in orthotopic liver-transplant patients remains to be established. We tested whether a combination of intravenous ganciclovir (GCV) followed by high dosages of oral acyclovir (ACV) for 4 months provided a higher degree of protection from CMV than oral ACV alone. METHODS One hundred sixty-seven liver-transplant recipients were randomized to receive 120 days of antiviral treatment starting at the time of transplantation consisting of either ACV 800 mg orally four times daily (n=84) or 14 days of GCV 5 mg/kg intravenously every 12 hr followed by oral ACV 800 mg four times daily (n=83). Prospective laboratory and clinical surveillance was performed to determine primary endpoints (onset of CMV infection and CMV disease) and secondary endpoints (rates of fungal and bacterial infection, allograft rejection, and survival after transplantation). One-year event rates are presented as cumulative percentages. RESULTS During the first year after transplantation, CMV infection developed in 57% of patients treated with ACV and in 37% of patients treated with GCV + ACV (P=0.001). CMV disease developed in 23% of patients treated with ACV and in 11% of patients treated with GCV + ACV (P=0.03). In seronegative recipients of allografts from CMV-seropositive donors (D+/R-), CMV disease developed in 58% of patients treated with ACV and in 25% of patients treated with GCV + ACV (P=0.04). In the D+/R- group, 54% of patients treated with ACV and 17% of patients treated with GCV + ACV developed infection with Candida albicans (P=0.05). CONCLUSIONS Prophylaxis of CMV infection in liver-transplant patients with 14 days of intravenous GCV followed by high-dosage oral ACV is more effective than high-dosage oral ACV alone at reducing CMV infection and disease, even for patients in the D+/R- CMV serological group.

Clinical predictors of relapse after treatment of primary gastrointestinal cytomegalovirus disease in solid organ transplant recipients.

Primary gastrointestinal cytomegalovirus (CMV) disease after solid organ transplantation (SOT) is difficult to treat and may relapse. Herein, we reviewed the clinical records of CMV D+/R− SOT recipients with biopsy‐proven gastrointestinal CMV disease to determine predictors of relapse. The population consisted of 26 kidney (13 [50%]), liver (10 [38%]) and heart (3 [12%]) transplant recipients who developed gastrointestinal CMV disease at a median of 54 (interquartile range [IQR]: 40–70) days after stopping antiviral prophylaxis. Except for one patient, all received induction intravenous ganciclovir (mean ± SD, 33.8 ± 19.3 days) followed by valganciclovir (27.5 ± 13.3 days) in 18 patients. Ten patients further received valganciclovir maintenance therapy (41.6 ± 28.6 days). The median times to CMV PCR negativity in blood was 22.5 days (IQR: 16.5–30.7) and to normal endoscopic findings was 27.0 days (IQR: 21.0–33.5). CMV relapse, which occurred in seven (27%) patients, was significantly associated with extensive disease (p = 0.03). CMV seroconversion, viral load, treatment duration, maintenance therapy and endoscopic findings at the end of therapy were not significantly associated with CMV relapse. In conclusion, an extensive involvement of the gastrointestinal tract was significantly associated with CMV relapse. However, endoscopic evidence of resolution of gastrointestinal disease did not necessarily translate into a lower risk of CMV relapse.

A prospective study of the polymerase chain reaction for detection of herpes simplex virus in cerebrospinal fluid submitted to the Clinical Virology Laboratory

Polymerase chain reaction (PCR) was prospectively performed with cerebrospinal fluid (CSF) from 51 patients whose CSF was available for analysis and was submitted for viral culture and/or herpes simplex virus (HSV) serology and 20 patients whose CSF was submitted exclusively to the Clinical Biochemistry Laboratory. Primers were used that flanked a 92 bp segment of the HSV DNA polymerase gene (35 cycles). Amplified products were electrophoresed on agarose gel, blotted onto nylon membrane, and probed with a 32P-labelled sequence internal to the primers. For nested PCR, 1 microliter of PCR product was amplified for an additional 35 cycles before electrophoresis and Southern blot analysis. Review of the clinical records revealed that 15 patients had central nervous system (CNS) infections. Specific HSV DNA sequences were detected in CSF specimens of three of the individuals [PCR(2), nested PCR(1)]. Two of these patients had disseminated HSV infection including encephalitis and one patient had aseptic meningitis. The diagnoses of the 12 patients with CNS infection who did not have HSV DNA detected in CSF included encephalitis [varicella-zoster virus (1), cytomegalovirus (1), Mycoplasma pneumoniae (1)], meningitis [Neisseria meningitidis (1), Coccidioides immitis (1), Enterovirus (1), aseptic meningitis (1)], varicella-zoster radiculitis (2), human immunodeficiency virus dementia (2), and transverse myelitis due to Epstein-Barr virus (1). Importantly, HSV DNA was also not detected in the CSF of the 36 patients who did not have CNS infection and 20 samples submitted exclusively to the Clinical Biochemistry Laboratory. Our findings demonstrate the utility of PCR as a rapid, non-invasive method for the routine laboratory diagnosis of CNS infection due to HSV.

Phaeohyphomycosis due to Alternaria species in transplant recipients.

R.D. Boyce, P.J. Deziel, C.C. Otley, M.P. Wilhelm, A.J. Eid, N.L. Wengenack, R.R. Razonable. Phaeohyphomycosis due to Alternaria species in transplant recipients.
Transpl Infect Dis 2010: 12: 242–250. All rights reserved

Current concepts in the diagnosis and management of left ventricular assist device infections

Left ventricular assist devices (LVAD) are increasingly being used both as a bridge to transplantation and for long-term myocardial surrogate destination therapy in patients with end-stage heart failure. Primarily owing to the presence of a driveline that connects the device to an external battery through an open skin incision, the rates of LVAD-related infections (LVADRIs) are high, ranging from 30 to 50%. LVADRIs can be broadly classified into driveline infection, pump pocket infection, bloodstream infection and endocarditis/pump or cannula infection. Diagnostic evaluation and management of these complicated infections can be quite challenging for clinicians involved in the care of these patients. Here, the authors summarize the current epidemiology, microbiology, diagnostic approach and management strategies for each type of LVADRI. The authors also review current concepts regarding antibiotic prophylaxis for LVAD implantation. Finally, the authors highlight the gaps in the knowledge of LVADRI and provide directions for future studies.

Strategies for Prevention of Infection After Cardiac Transplantation

Infection remains a major cause of morbidity and mortality after cardiac transplantation. Most infections occur during the first few months after transplantation. Although late infection does occur, the risk of infection during maintenance immunosuppression is low in the absence of recurrent rejection that necessitates augmentation of suppression of the immune response. Before cardiac transplantation, the risk factors for infectious disease in potential candidates should be assessed. A detailed history of past infections should be elicited, and patients should be screened for the presence of active indolent infection. In addition, potential donors must be thoroughly assessed for organ-transmittable infection. Many common infections that may occur after cardiac transplantation can be prevented with the use of appropriate prophylactic regimens directed toward cytomegalovirus, Toxoplasma gondii, Pneumocystis carinii, and herpes simplex virus. Periodic surveillance serologic tests and cultures after cardiac transplantation facilitate early diagnosis and prompt institution of appropriate therapy.

Stability in the cumulative incidence, severity and mortality of 101 cases of invasive mucormycosis in high‐risk patients from 1995 to 2011: a comparison of eras immediately before and after the availability of voriconazole and echinocandin‐amphotericin combination therapies

As invasive mucormycosis (IM) numbers rise, clinicians suspect prior voriconazole worsens IM incidence and severity, and believe combination anti‐fungal therapy improves IM survival. To compare the cumulative incidence (CI), severity and mortality of IM in eras immediately before and after the commercial availability of voriconazole all IM cases from 1995 to 2011 were analysed across four risk‐groups (hematologic/oncologic malignancy (H/O), stem cell transplantation (SCT), solid organ transplantation (SOT) and other), and two eras, E1 (1995–2003) and E2, (2004–2011). Of 101 IM cases, (79 proven, 22 probable): 30 were in E1 (3.3/year) and 71 in E2 (8.9/year). Between eras, the proportion with H/O or SCT rose from 47% to 73%, while ‘other’ dropped from 33% to 11% (P = 0.036). Between eras, the CI of IM did not significantly increase in SCT (P = 0.27) or SOT (P = 0.30), and patterns of anatomic location (P = 0.122) and surgical debridement (P = 0.200) were similar. Significantly more patients received amphotericin‐echinocandin combination therapy in E2 (31% vs. 5%, P = 0.01); however, 90‐day survival did not improve (54% vs. 59%, P = 0.67). Since 2003, the rise of IM reflects increasing numbers at risk, not prior use of voriconazole. Frequent combination of anti‐fungal therapy has not improved survival.

Disseminated microsporidiosis in a renal transplant recipient: case report and review of the literature

Microsporidia are opportunistic pathogens that usually cause a limited disease in the gastrointestinal tract. Occasionally, they can cause disseminated disease. In solid organ transplant recipients, disseminated disease has been reported only rarely. We describe a 68‐year‐old woman who presented with fever, cough, and acute kidney injury 6 months after kidney transplantation. Dissemination was confirmed by identification of microsporidial spores in urine and bronchoalveolar lavage fluid. Polymerase chain reaction analysis identified the species as Encephalitozoon cuniculi.