Multilocus Sequence Analysis Reveals Genetic Diversity in Xanthomonads Associated With Poinsettia Production.

Xanthomonas axonopodis pv. poinsettiicola is traditionally identified as the primary causal agent of bacterial leaf spot on poinsettia (family Euphorbiaceae). Sixty-seven strains of xanthomonads isolated from lesions associated with several species within the family Euphorbiaceae were collected over a 64-year period. The pathogenicity of these strains was compared on several potential hosts and they were analyzed by multilocus sequence analysis (MLSA) using six housekeeping genes. The 67 Xanthomonas strains associated with poinsettia production were separated into three distinct clades based on MLSA. The first clade identified contained the X. axonopodis pv. poinsettiicola reference strain (LMG849PT). A second clade was more closely related to X. hortorum pv. pelargonii (LMG7314PT) and the third clade contained the X. codiaei type strain (LMG8678T). This analysis indicated that there may also be other closely related pathovars or species of Xanthomonas that can infect poinsettia. Strains from the three clades could not be distinguished by symptoms or virulence on poinsettia plants. Strains capable of infecting geranium were found in all three clades, although the extent of leaf spot formation and number of systemic infections were significantly less than those produced by X. hortorum pv. pelargonii strains, typically the main causal agent of bacterial leaf spot on geranium. Clade III also contained strains isolated from zebra plant (Aphelandra squarrosa, family Acanthaceae), which is a newly recognized host for X. codiaei and X. axonopodis pv. poinsettiicola. Xanthomonas leaf spot is a serious threat to poinsettia production that can be caused by several Xanthomonas spp. that can infect different ornamental plant hosts. It is imperative that growers maintain a strict sanitation program because reservoirs of inoculum can occur on a number of ornamental hosts.

Genetic analyses of Xanthomonas axonopodis pv. dieffenbachiae strains reveal distinct phylogenetic groups.

A comprehensive analysis of 175 Xanthomonas axonopodis pv. dieffenbachiae strains isolated from 10 Araceae hosts was done to identify pathogen variation. The strains were subjected to repetitive extragenic palindromic sequence polymerase chain reaction and four major phylogenetic clusters were generated. A subset of 40 strains isolated from Anthurium, Dieffenbachia, and Syngonium was further defined by amplified fragment length polymorphism and fatty acid methyl ester analysis and the same four phylogenetic clusters were observed. Comparison of representative strains in the first three clusters using DNA-DNA hybridization and multilocus sequence analysis supports the previous reclassification of strains in cluster I, including the X. axonopodis pv. dieffenbachiae pathovar reference strain (LMG695), to X. citri. Our research findings indicate that strains in cluster I, isolated primarily from anthurium, probably represent an undescribed pathovar. Other phylogenetic subclusters consisting primarily of strains isolated from xanthosoma and philodendron in clusters III and IV, respectively, may yet represent other undescribed species or pathovars of Xanthomonas.

First Report of a Leaf Spot Disease of Golden Dewdrop (Duranta erecta) Caused by Pseudomonas cichorii and a Xanthomonas Species in Florida.

Duranta erecta (Verbenaceae) is used extensively in southern states as an ornamental shrub and has replaced boxwood as the most common short hedge accenting flower beds. Over the past 2 years, during warm wet periods, dark necrotic leaf spots have been observed on golden dewdrop plants in Florida. Isolations from these spots on Difco nutrient agar (NA) consistently yielded two types of bacterial colonies that were not always simultaneously present: 1) round butyrous, bright yellow and 2) flat cream-colored. Both were 2 mm in size after 48 h, gram-negative, and produced a hypersensitivity reaction (HR) on tobacco cv Hicks. Yellow colony bacteria were oxidase negative and non-fluorescent on King's medium B (KMB) (1). Cream-colored colony bacteria were oxidase positive and fluorescent on KMB. Three isolates of both types were selected for further study. Partial 16S rDNA sequencing and fatty acid analysis (FAME) MIDI Microbial Identification System (Microbial ID, Inc., Newark, DE) were used for identification of strains. The 16S rDNA primers used were; forward primer AMB14 5'-TCCAGCAATGCCGCGTGTGT-3' and reverse primer AMB13 5'-CATCCACCGCTTGTGCGGGT-3'. The PCR program consisted of an initial denaturing cycle of 95°C for 2 min followed by 30 cycles of denaturing at 95°C for 30 s, annealing at 60°C for 40 s and extension at 72°C for 1 min and one final extension at 72°C for 10 min. Using FAME analysis, the three strains of the cream-colored colony type were identified as Pseudomonas cichorii with high similarity values (0.907, 0.961, 0.819) and this corresponded well with the 16S rDNA sequences where 99% sequence identity was observed with P. cichorii strain JBC1 16S ribosomal RNA gene, partial sequence GenBank Accession No. JF951725. Two of the three yellow colony strains were identified by MIDI FAME profiles as Xanthomonas axonopodis pv. manihotis with similarity coefficients of 0.767 and 0.826. The third strain had a low similarity match to X. a. pv. carotae (0.541). The 16S rDNA sequencing of these strains showed 98% sequence identity to X. citri subsp. citri strain SA1 16S ribosomal RNA gene only, partial sequence identity JQ890091.1, thus indicating a possible undescribed X. axonopodis pathovar. To satisfy Koch's postulates, three golden dewdrop 'Golden Mound' plants were sprayed with a suspension of 108 CFU/ml of a 2-day NA culture of each strain, bagged for 24 h to raise humidity, and placed in a greenhouse. A strain of P. cichorii (P409) isolated from chrysanthemum was used as a positive control when comparing cream-colored strains. A saline buffered control was used as a negative control. Within 3 weeks, leaf spots developed on plants sprayed with each of the six strains, including positive control strain of P. cichorii. Reisolations yielded the same type of colony as the originally inoculated strain. Inoculation experiments were repeated three times with a minimum of three plants per isolate with similar results. To our knowledge, this is the first report in the United States of bacterial leaf spot caused by P. cichorii and X. axonopodis on golden dewdrop. An earlier morphological and physiological description of a Xanthomonas sp. was done on Duranta in India in 1962 (2). Due to the difficulty in controlling bacterial diseases and the popularity of Duranta spp. in the landscape, these diseases may present a problem in ornamental trade. References: (1) E. O. King et al. J. Lab. Clin. Med. 44:301, 1954. (2) M. C. Srinivasan et al. Proc. Indian Acad. Sci. 56:88, 1962.

A novel DRB1*04 allele.

Discovery of the novel DRB1*0464 allele is described. This allele contains a nucleotide substitution in codon 13 that changes the amino acid histidine coded for in all other DRB1*04 alleles to tyrosine. This allele was found in a parent and one child of a North American Caucasian family with the haplotype: A*03, B*07, DRB1*0464, DRB4*0103, DQB1*0301.

Cardiovascular events following renal transplantation: role of traditional and transplant-specific risk factors.

Cardiovascular mortality is increased in transplant recipients. However, studies including non-fatal events are critical to assess the burden of disease and to identify novel risk factors. We described the incidence of fatal and non-fatal events, and explored associations and interactions among traditional and transplant-specific risk factors and cardiovascular events (CVE) in a cohort of 922 patients transplanted between 1993 and 1998. One hundred and seventy-six patients experienced 201 CVE (111 cardiac, 48 cerebrovascular, 42 peripheral-vascular). Most CVE were non-fatal. Factors associated with cardiac events were (adjusted hazard ratios) tobacco (3.53; P<0.001), obesity (2.92; P<0.001), diabetes (2.63; P<0.001), multiple rejections (2.19; P=0.008), prior CVE (2.0; P=0.004), dialysis >1 year (1.91; P=0.007), and overweight status (1.68; P=0.04); with cerebrovascular events: diabetes and peritoneal dialysis (11.95; P<0.001), age >45 (6.77; P<0.001), diabetes (4.87; P<0.001), prior CVE (3.73; P<0.001), creatinine >141 micromol/l (3.16; P=0.001), peritoneal dialysis (3.06; P=0.027), and obesity (0.32; P=0.046); with peripheral-vascular events: diabetes (8.48; P<0.001), tobacco and cytomegalovirus (3.88; P<0.001), age >45 (2.31; P=0.019), and prior CVE (2.25; P=0.016); with mortality: tobacco and deceased-donor (3.52; P<0.001), age >45 (1.81; P=0.002), diabetes (1.76; P=0.002), pulse pressure (1.64; P=0.029), prior CVE (1.52; P=0.04), and dialysis >1 year (1.47; P=0.04). The majority of CVE post-transplant were non-fatal. Previous CVE was strongly associated with CVE post-transplant. Interactions among transplant-specific and traditional risks impacted significantly the incidence of CVE. Modifiable factors such as duration of dialysis, deceased-donor transplantation, and acute rejection should be viewed as cardiovascular risks.

Classification and Identification of Xanthomonas translucens Isolates, Including Those Pathogenic to Ornamental Asparagus.

ABSTRACT In order to confirm and refine the current classification scheme of Xanthomonas translucens and to identify novel strains from ornamental asparagus, a collection of field and reference strains was analyzed. Rep-polymerase chain reaction (PCR) genomic fingerprint profiles were generated from 33 isolates pathogenic to asparagus as well as 61 X. trans-lucens reference strains pathogenic to cereals and grasses. Amplified ribo-somal gene restriction analysis profiles were obtained from most of these and 29 additional Xanthomonas reference strains. Rep-PCR genomic fingerprint profiles of all strains were compared with those in a large Xanthomonas database using computer-assisted analysis. Rep-PCR ge-nomic fingerprinting facilitated the characterization and discrimination of X. translucens, including the pathovars arrhenatheri, graminis, phlei, phleipratensis, and poae, as well as a number of strains received as X. translucens pv. cerealis. Strains received as pathovars hordei, secalis, translucens, undulosa, and other cerealis strains were grouped in two subclusters that correspond to the recently redefined pathovars X. trans-lucens pvs. undulosa and translucens. All 33 novel isolates from ornamental asparagus (tree fern; Asparagus virgatus) were identified as X. translucens pv. undulosa. Moreover, a unique amplified small subunit ribosomal gene MspI/AluI restriction profile specific for all X. translucens strains tested, including those pathogenic to asparagus, allowed discrimination from all other Xanthomonas spp. Although phage tests were inconclusive, the classification of the asparagus strains within the X. translucens complex was supported by pathogenicity assays in which all the isolates from ornamental asparagus induced watersoaking on wheat. Surprisingly, several X. translucens reference strains affected asparagus tree fern as well. That the novel asparagus isolates belong to X. translucens pv. undulosa is extraordinary because all hosts of X. translucens pathovars described to date belong only to the families Gramineae and Poaceae, whereas asparagus belongs to the phylogenetically distant family Liliaceae.

Control of Bacterial Wilt of Geranium with Phosphorous Acid.

Various bactericides were screened for efficacy in protecting geranium plants (Pelargonium hortorum) from Ralstonia solanacearum infection. Many of these bactericides were found to slow the disease progress; however, they were not able to protect the plants from infection and subsequent death. Potassium salts of phosphorous acid were found to be effective in protecting plants from infection when applied as a drench. The active portion of the potassium salts was found to be phosphorous acid (H3PO3). Phosphorous acid was found to inhibit in vitro growth of R. solanacearum. It is thought to be protecting plants from infection by acting as a bacteriostatic compound in the soil. The plants, however, are not protected from aboveground infection on wounded surfaces. Phosphorous acid drenches were shown to protect geranium plants from infection by either race 1 or 3 of R. solanacearum. Other phosphorous-containing products commonly used in the industry, such as phosphorus pentoxide (P2O5) and phosphoric acid (H3PO4), were not able to protect plants from bacterial wilt infection.

Characterization of Erwinia Populations from Nursery Retention Ponds and Lakes Infecting Ornamental Plants in Florida.

Water shortages in Florida are occurring due to intense utilization of the aquifer system by municipalities and agriculture, and because of continued deficits in annual rainfall. Water districts therefore, are, recommending the use of recycled irrigation water, stormwater runoff, reclaimed municipal sewage water, and lakes for agricultural use. With recycled water, however, there is potential for both introducing and concentrating plant pathogens. In Florida, Erwinia soft-rot bacteria (synonym Pectobacterium) cause extensive crop losses in ornamental plant production. To determine Erwinia spp. population levels, samples were taken monthly for 1 year from four hypereutropic lakes and eight nursery retention ponds. Seventy-seven Erwinia strains were collected by both direct plating and by an enrichment process. With the direct plating method, 0 to 29 CFU/ml were detected on sodium polypectate medium. Significantly higher populations of Erwinia were detected in retention ponds of nurseries that were actively reutilizing their water. Erwinia strains were identified to species by fatty acid analysis and biochemical tests. Strains were further characterized by repetitive element-polymerase chain reaction (rep-PCR) and compared with 120 strains of Erwinia collected from ornamentals over a 17-year period in Florida. Using rep-PCR, most strains were clustered into two heterogeneous populations of E. chrysanthemi and E. carotovora subsp. carotovora in a 1:2 and a 1:4 ratio for isolates from ornamentals and from water, respectively. Within each population of E. chrysanthemi and E. carotovora, genetically different subpopulations could be identified that contained high percentages of Erwinia strains from water sources. Even though genetic differences exist, 99% of the strains from water sources were found to be pathogenic on dieffenbachia. Without water treatment of irrigation and stormwater runoff, there is a potential for both introducing and concentrating Erwinia populations within these water sources.

First Report of Xanthomonas axonopodis Infecting Agapanthus in Florida.

Agapanthus praecox subsp. orientalis, commonly called African lily or lily-of-the-Nile, bears large, round, blue or white flowers above attractive dark green foliage. Because of these horticultural features, this member of the family Liliaceae, has become a popular perennial bedding plant. For the past 2 years during warm wet periods, symptoms of chlorotic, water-soaked, leaf-streaks have been observed on agapanthus production in Florida. Round butyrus, bright yellow colonies were consistently isolated on nutrient agar. Bacteria were characterized as gram negative, catalase positive, motile, strictly aerobic, and not hydrolytic on starch. Using fatty acid analysis (FAME) and the MIDI Microbial Identification System with software version TSBA 3.90 (Microbial ID, Inc., Newark DE), three strains were further characterized and identified as Xanthomonas axonopodis with similarity coefficients to X. axonopodis pv. dieffenbachiae (0.907, 0.915, and 0.944) and to X. axonopodis pv. poinsetticola (0.912, 0.922, and 0.916). The three isolates were each inoculated on three plants each of agapanthus cv. Blue African lily, Dieffenbachiae maculata cv. Camille, and poinsettia, Euphorbia pulcherrima cv. PeterStar Red. Plants were sprayed with a suspension of each isolate at 1 × 108 CFU/ml, bagged for 24 h to raise humidity, and placed in a glasshouse for symptom development. Strains of X. axonopodis pv. poinsetticola (NZTCC 5779) and X. axonopodis pv. dieffenbachiae (X1718) were used as positive controls. Within 3 weeks, isolates from agapanthus produced leaf streaks on agapanthus plants, small, scattered, water-soaked lesions on dieffenbachia leaves, and no symptoms on poinsettia. No symptoms developed on the agapanthus plants when inoculated with either control strain. Both control strains formed lesions on leaves of their original host species. Xanthomonas was reisolated from treatments with symptomatic leaves. Plant inoculations were repeated with similar results. Although the agapanthus isolates were highly similar in FAME profiles to X. axonopodis pv. dieffenbachiae, symptoms produced on dieffenbachia were mild as compared with those produced by the dieffenbachia isolate. Therefore, these isolates may represent a distinct pathovar.

Valaciclovir prophylaxis of cytomegalovirus infection and disease in renal transplantation: an economic evaluation.

BACKGROUND: Cytomegalovirus (CMV) disease is a major cause of morbidity and mortality in solid organ transplant patients and is associated with large additional healthcare expenditures. An economic evaluation of valaciclovir CMV prophylaxis in a renal transplant population is reported. METHODS: Medical resource use data were collected alongside a multicenter multinational randomized, placebo-controlled, double-blind trial of valaciclovir CMV prophylaxis in renal transplantation. Patients were stratified into donor seropositive/recipient sero-negative (D+R-) and recipient seropositive (R+) groups. Patients were followed-up 6 months posttransplant. A cost-effectiveness analysis from the perspective of the French health care system was performed using the number of cases of CMV disease avoided at 6 months as the clinical endpoint. RESULTS: Resource use was significantly increased among patients who developed CMV disease compared to those who did not develop disease. In the high risk D+R- group, valaciclovir prophylaxis was associated with an average of 5.5 fewer inpatient hospital days (P < OR =0.05) and with significantly lower use of other healthcare resources. In the R+ group, valaciclovir prophylaxis prevented cases of CMV disease at a marginally greater mean cost per patient compared with placebo. For D+R- patients valaciclovir prophylaxis was therefore an economically superior strategy, resulting in fewer cases of CMV disease and lower total mean healthcare expenditures. CONCLUSIONS: Valaciclovir CMV prophylaxis in renal transplantation is a more cost-effective therapy compared with placebo, in the high-risk D+R- patient population. For the R+ group, the incremental cost per case of CMV disease was modest.

Reversible acute renal allograft dysfunction due to gabapentin.

BACKGROUND: The use of gabapentin as an effective analgesic agent for neuropathic pain has expanded considerably. Its lack of both anticholinergic side effects and interference with the metabolism of drugs via the cytochrome P450 pathway make it especially useful for transplant recipients. METHODS AND RESULTS: We describe the case of a renal transplant recipient with a long-term stable functioning allograft who developed reversible acute renal dysfunction after beginning gabapentin therapy for chronic pain due to diabetic neuropathy. CONCLUSIONS: We suggest that gabapentin may cause acute renal dysfunction by a mechanism involving renal afferent vasoconstriction. Caution should be employed when considering the use of gabapentin in transplant recipients, especially when combined with other agents that may potentiate renal vasoconstriction.

Phase I trial of HuM291, a humanized anti-CD3 antibody, in patients receiving renal allografts from living donors.

BACKGROUND: HuM291 is a humanized anti-CD3 monoclonal antibody engineered to reduce binding to Fcgamma receptors and complement fixation. HuM291 has a long serum half-life and mediated profound depletion of circulating T cells in chimpanzees; HuM291 also has significantly less mitogenic and cytokine-releasing activity than OKT3 in vitro. METHODS: A phase I dose-escalation study was conducted in 15 end-stage renal disease patients scheduled for renal allografts from living donors. Patients received one i.v. HuM291 injection before transplantation. Five doses were tested: 0.015 microg/kg, 0.15 microg/kg, 0.0015 mg/kg, 0.0045 mg/kg, and 0.015 mg/kg. Patients were followed for adverse events, laboratory abnormalities, serum cytokine levels, pharmacokinetics, and CD2+, CD3+, CD4+, and CD8+ T cell counts. RESULTS: HuM291 was well tolerated; most adverse events were mild to moderate in severity and included headache, nausea, chills, and fever. These occurred within the first few hours after HuM291 administration, resolved within 24 to 48 hr, and were likely related to cytokine release. In general, peak tumor necrosis factor-alpha, interferon-gamma, and interleukin-6 levels were detected 1 to 6 hr postdosing only at the three highest doses and were generally undetectable by 24-hr postdosing. Serious adverse events possibly related to HuM291 included clotting of a fistula (two patients), chemical cellulitis (one patient), and increased serum creatinine/decreased hematocrit (one patient). At doses > or = 0.0015 mg/kg (0.1 mg/70 kg), HuM291 induced rapid, marked depletion of peripheral T cells within 2 hr; duration of T cell depletion was dose dependent. At the two highest dose levels, T cells remained depleted for approximately 1 week. CONCLUSIONS: A single HuM291 dose rapidly depleted circulating T cells in a dose-dependent manner and was associated with only mild to moderate symptoms of cytokine release.

Factors in cardiac risk stratification of candidates for renal transplant.

BACKGROUND: Renal transplant candidates are at high risk of fatal and nonfatal cardiac events. METHODS: This study evaluated five clinical risk factors--age at least 50 years, insulin-requiring diabetes mellitus, angina, congestive heart failure and an abnormal electrocardiogram (ECG) (excluding left ventricular hypertrophy)--that had been used in the first tier of a two-tiered prospectively applied risk stratification algorithm. RESULTS: Using multiple logistic regression analysis, age at least 50 years, abnormal ECG, and diabetes mellitus were independently predictive of cardiac death. Of the two remaining clinical risk factors, the presence of angina had independent predictive value for nonfatal cardiac events (myocardial infarction, coronary angioplasty, bypass surgery, and unstable angina). The independent predictive value of congestive heart failure approached statistical significance. CONCLUSION: Clinical risk-factor analysis is helpful in identifying renal transplant candidates at high risk for fatal or nonfatal cardiac events.

Renal transplantation across the ABO barrier using A2 kidneys.

BACKGROUND: The waiting list for cadaveric kidney transplantation has continued to grow, and with the relative scarcity of cadaver donors, the median waiting time for patients in the United States increased to 824 days in 1994. The median waiting times for patients with blood groups B or O were 1329 and 1007 days, respectively. Allocation of blood group A2 kidneys (20% of group A) to blood group O and B patients expands their potential donor pool and shortens their waiting time for a kidney transplantation. METHODS: Between May 1991 and June 1998, we transplanted 15 A2 kidneys into 6 blood group O and 9 blood group B patients. Anti-A isoagglutinins were measured before transplantation, and patients with anti-A1 titers > or = 1:8 underwent plasmapheresis (PP). RESULTS: One patient with high titer anti-A antibodies, who did not receive PP, lost her allograft because of hyperacute rejection. Allograft function was excellent in the remaining 14 patients, with a mean serum creatinine level of 1.7 (+/-0.89) mg/dl at 1 month and 1.3 (+/-0.34) mg/dl at 1 year. The actuarial 1-year graft survival rate was 93.3+/-6.4% and the patient survival rate was 100%. CONCLUSION: We conclude that the allocation of blood group A2 kidneys for blood group O and B recipients is a practical way to expand the donor pool for these transplant candidates. PP may be important for reducing the levels of anti-A1 and anti-A2 antibodies and for reducing the risk of hyperacute rejection. Splenectomy seems to be unnecessary.

HLA-identical sibling renal transplantation--a 21-yr single-center experience.

Human lymphocyte antigen (HLA)-identical sibling organs offer the best long-term outcomes for recipients of a renal transplant apart from an identical twin. Unlike cadaveric transplants, however, factors that affect long-term survival of these immunologically privileged grafts are not well described. We reviewed 108 HLA-identical transplants performed at our institution between January 1977 and February 1993. Variables chosen for graft survival analysis were: gender, age and ABO blood type of donors and recipients, panel reactivity antibodies (PRA), blood transfusions prior to transplant, pregnancies, and the underlying renal disease. Additionally, incidence of acute rejection (AR), timing of AR, serum creatinine levels at 1 wk and at 1 yr, and presence of hypertension were included in the analysis. Mean follow-up was 130.9 +/- 58.2 months (range 38-250 months). Actual 5-yr patient and graft survivals were 92 and 88%, respectively. Thirty-eight grafts were lost, and 22 recipients died during the observation period. Death was the main cause of graft failure. Cardiac events accounted for the majority of deaths. AR occurred in 46% and repeated rejections in 11% of recipients. Actuarial graft survival at 10 yr was poorer for patients with any AR (69%), and significantly worse with repeated AR (33%), compared to patients without AR (86%), p = 0.001). Sixty percent of all rejections and 88% of the first rejections occurred in the first 60 d post-transplantation. The first AR that occurred after 60 d was associated with poor graft survival (49 vs. 70%, p = 0.04). Recipients with renal diseases with potential to recur (membranous glomerulonephritis (MGN), membrano-proliferative glomerulonephritis (MPGN), focal and segmental glomerulonephritis (FSGN), polyarteritis nodosa (PAN), rapid progressive glomerulonephritis (RPGN), Henoch-Schoenlein purpura (HSP), diabetes mellitus (DM), interstitial nephritis, systemic lupus erythematosus (SLE) and chronic glomerulonephritis (CGN)) faired worse as a group than recipients with hypertensive nephrosclerosis (HTN), autosomal dominant polycystic kidney disease (ADPKD), Alport's, reflux or congenital dysplasia (68 vs. 96% at 10 yr, p = 0.0009). Poor patient survival was seen in diabetics (71 vs. 88% at 10 yr, p = 0.01). There was a trend to poorer graft survival in diabetic recipients when compared to non-diabetics (65 vs. 81% at 10 yr, p = 0.054). Elevated creatinine at 1 yr was associated with worse graft survival. Likewise, the magnitude of creatinine increase during the first year directly correlated with the risk of graft loss. Hypertensive patients were more likely to lose their grafts than normotensive recipients (72 vs. 86%, p = 0.04). Pre-transplant blood transfusion, pregnancy, and PRA level were not associated with increased graft failure or AR. Graft survival was not affected by gender, age, or ABO blood type of donors or recipients. In conclusion, better prevention and treatment of AR, hypertension, and cardiac disease should improve graft and patient survival. Close attention to recurrence of disease and subtle changes in the creatinine level during the first year might dictate early diagnostic and, hopefully, therapeutic interventions.

Heterogeneity of Xanthomonas campestris pv. hederae Strains from Araliaceous Hosts.

ABSTRACT Xanthomonas campestris pv. hederae (synonym X. hortorum pv. hederae) strains (59 total) were collected from plants in the araliaceae family. Strains were isolated from Hedera helix, Schefflera arboricola, Brassaia actinophylla, and Polyscias spp. from Florida, California, Hawaii, and New Zealand. All strains produced yellow mucoid growth; hydrolyzed esculin, starch, casein and gelatin; were pectolytic; produced urease; and grew on minimal media containing asparagine. All bacterial strains were pathogenic on H. helix (English ivy), B. actinophylla (dwarf schefflera), and Polyscias fruticosa (ming aralia). No differences in symptomatology were detected among strains; however, severity of symptoms usually was greatest on the host of origin. In planta growth rates of representative strains isolated from H. helix, B. actinophylla, and Polyscias spp. also were compared among these three hosts. In all cases, populations grew more rapidly when strains were inoculated to their original host species. All 59 bacterial strains were compared by 95-carbon source GN microplate, fatty acid methyl ester (FAME), and restriction fragment-length polymorphisms (RFLP), with the pulse-field gel electrophoresis method, analyses. All three analyses grouped strains into two distinct groups that correlated with the host of origin. Using metabolic profiles, 75% of the H. helix strains were separated from strains isolated from Brassaia and Schefflera and 95% of the Polyscias strains. FAME analysis separated strains into two distinct groups, with 96% of the H. helix strains placed in one group. RFLP analysis placed all of the H. helix and Schefflera strains in one group, as well as 33% of the Brassaia strains, whereas the other group contained all of the Polyscias strains and the remainder of the Brassaia strains. It is apparent that the pathovar hederae is made up of heterogeneous populations that can be separated by biochemical, pathological, genetic, and physiological analyses into two groups that are closely associated with the host of origin.

First Report of Ralstonia (Pseudomonas) solanacearum Infecting Pot Anthurium Production in Florida.

Xanthomonas campestris pv. dieffenbachiae is a common pathogen of pot anthurium production in Florida. While X. campestris pv. dieffenbachiae was isolated from systematically infected plants with chlorotic, necrotic, and wilted leaves, a fluidal, beige bacteria was occasionally isolated on nutrient agar (Difco, Detroit, MI), as opposed to the common, yellow pigmented Xanthomonas sp. Distinction in the symptomology of plants systematically infected with a Xanthomonas sp. or this new bacterium could not be made. Three isolates were obtained of this unidentified bacterium from leaves and stems of three separate plants. With FAME (fatty acid methyl esters) analysis, using MIDI (Microbial Identification System, software version TSBA 3.90 [Newark, DE]), these isolates were classified as Ralstonia (Pseudomonas) solanacearum (syn. Burkholderia solanacearum) with a mean similarity indice of 0.895. Isolates were found to be gram negative, oxidase negative, catalase positive, motile, strictly aerobic, and metabolically classified as biovar 1; they accumulated poly-ß-hydroxybutyrate and produced a hypersensitive response on tobacco within 24 h. A characteristic fluidal, white growth with a distinctive, red, swirling, egg-shaped, pigmentation pattern was observed on triphenyltetrazolium chloride medium. Further confirmation of identity as R. solanacearum was obtained by polymerase chain reaction amplification and electrophoretic analysis with species-specific primers (2), which in all cases produced a 148-bp product along with control strains. The three isolates were inoculated onto three plants of anthurium, tomato, triploid banana, and pothos. Inoculations were done at least twice; plants were inoculated either by stabbing the plant stems with a needle dipped in a suspension of bacteria or by applying 10 ml of a 1 × 108 CFU/ml suspension to the soil of the test plants. Chlorosis, necrosis, and wilt symptoms appeared within 2 weeks on all plant species tested. Recently, pothos (Epipremnum aureum) cuttings imported to Florida from Costa Rica have been implicated as a source of R. solanacearum (1). Imported cuttings of pothos were being grown in hanging baskets over the infected anthuriums. Although no R. solanacearum infections were detected in the pothos, these imported plants are the probable source of the initial inoculum for this disease outbreak on anthuriums. References: (1) D. J. Norman and J. M. F. Yuen. Phytopathology 87:S70, 1997. (2) S. E. Seal et al. Appl. Environ. Microbiol. 58:3751, 1992.

Interaction between tacrolimus and nefazodone in a stable renal transplant recipient.

Tacrolimus (FK-506) is an important immunosuppressive agent most often given for maintenance immunosuppression to prevent acute cellular organ rejection. A 57-year-old woman with end-stage renal disease presumed secondary to chronic glomerulonephritis underwent a living related renal allograft transplantation. She tolerated the surgery well and was discharged on postoperative day 5. She was stabilized with prednisone, azathioprine, and tacrolimus. Two years after transplantation, nefazodone 50 mg twice/day orally was prescribed due to depression. After 1 week of nefazodone therapy the patient experienced headache, confusion, and "gray areas" in her vision, without abnormal ophthalmologic findings. Her serum creatinine was elevated to 2.2 mg/dl (baseline 1.5 mg/dl), and trough tacrolimus level was markedly elevated (> 30 ng/ml). Both tacrolimus and nefazodone are metabolized by the cytochrome P450 (CYP) 3A4 system. We suspect that nefazodone inhibits metabolism of tacrolimus. Coadministration of antidepressant agents such as nefazodone, or any other drug that inhibits the CYP3A4 isoenzyme subfamily, should be anticipated to interfere with tacrolimus metabolism. Monitoring blood concentrations of tacrolimus is vital, and appropriate dosage adjustments are required when the two drugs are administered concurrently to avoid serious interactions such as nephrotoxicity and neurotoxicity.

Efficacy and safety of low molecular weight heparin in renal transplantation.

BACKGROUND: Deep venous thrombosis (DVT) is a common problem with potentially devastating results in patients undergoing major surgical procedures. Certain renal transplant recipients are particularly at risk for allograft loss as a consequence of renal vein and artery thrombosis. Over the past few years, low molecular weight heparin has been well established as an accepted modality of treatment and prophylaxis of DVT. The efficacy and safety of low molecular weight heparin in the prophylaxis of DVT following renal transplantation in adults has not previously been reported. METHODS: Dalteparin was administered to 120 adult renal transplant recipients postoperatively at the Oregon Health Sciences University. RESULTS: No patient developed allograft arterial or venous thrombosis. One patient developed subclavian vein thrombosis. No bleeding complications were encountered, and side effects were very minimal. CONCLUSION: Prophylaxis with dalteparin is an effective and safe modality for the prevention of thrombosis in adult patients undergoing renal transplantation.