Plants release, pathogens decease: Plants with documented antimicrobial activity are associated with Campylobacter and faecal indicator attenuation in stormwater biofilters

Stormwater biofilters demonstrate promising treatment of faecal microorganisms, however performance can vary with design and operational conditions. This study investigated whether plants with significant documented antimicrobial activity could improve faecal bacterial treatment within biofilters. Laboratory-scale biofilters (n = 30) were dosed with synthetic stormwater containing faecal bacteria Escherichia coli, Enterococcus faecalis and Campylobacter jejuni under south-eastern Australian climatic conditions. Systems vegetated with Melaleuca species, renowned for their in vitro antimicrobial activity, consistently enhanced removal of all tested culturable bacteria in total outflow and submerged zone water relative to other plant configurations. Within just 1-2 days of stormwater dosing, M. linariifolia submerged zones demonstrated significantly reduced bacterial concentrations compared to C. appressa (p = 0.023 and <0.001 for C. jejuni and E. coli, respectively), removing ∼1.47 log10 MPN/100 mL E. coli, ∼1.14 log10 MPN/100 mL E. faecalis and ∼0.81 log10 MPN/L C. jejuni from inflow. These trends continued even after all but one M. linariifolia replicate perished during an extended drying period (p = 0.002 and 0.003 for C. jejuni and E. coli, respectively). Through a systematic process of elimination, these observations were attributed to enhanced bacterial attenuation with elevated plant inhibitory activity. Cumulative biofilter age reinforced plant-mediated bacterial treatment (p = 0.023 for E. faecalis), ostensibly due to increased plant size/growth and net biological activity. Notably, E. coli and E. faecalis attenuation improved with prolonged antecedent drying length (14 vs. 4 days; p < 0.0001 for both), while the converse was observed for C. jejuni (not significant). This study addresses significant knowledge gaps around plant-mediated faecal microbe treatment within biofilters, providing key direction for real-world system design to optimise stormwater pathogen treatment.

Plants against pathogens: Effect of significant antimicrobial-producing plants on faecal microbe inactivation throughout the soil profile of stormwater biofilters

Stormwater biofilters have demonstrated promising yet variable removal of faecal microorganisms. Significant antimicrobial-producing plants have been proposed as an inexpensive, safe and easily adaptable component of biofilter design to enhance faecal pathogen treatment. The aim of the present study was to investigate whether significant antimicrobial-producing plants improved faecal bacterial inactivation throughout the biofilter soil profile, focusing on four key treatment zones. These were specifically the top sediment/surface layer; the rhizosphere (soil directly attached to and influenced by plant roots); bulk soil (soil not directly associated with roots); and the submerged/saturated zone. Biofilters were configured with either: (1) no plant; (2) Carex appressa, the most highly recommended plant species in Australian biofilter adoption guidelines; or (3) one of two significant antimicrobial-producing Australian plant species, Melaleuca linariifolia or Melaleuca fulgens (n = 3 each). Following 16 months' maturation, systems were dosed with semi-synthetic stormwater containing faecal bacteria Escherichia coli and Enterococcus faecalis to monitor their ensuing die-off within all major biofilter treatment zones. Bacterial inactivation was generally more rapid in M. fulgens and M. linariifolia than C. appressa biofilters, with E. faecalis demonstrating an overall enhanced resistance to inactivation. Top sediment tended to exhibit the highest inactivation rates, significantly correlated with sunlight exposure. Conversely, the rhizosphere supported comparatively prolonged faecal bacterial survival. The authors recommend further investigation of melaleucas and similar highly antimicrobial-producing plants for enhanced faecal pathogen treatment within biofilters and related treatment contexts.

Rise of the killer plants: investigating the antimicrobial activity of Australian plants to enhance biofilter-mediated pathogen removal

BACKGROUND

Biofilters are soil-plant based passive stormwater treatment systems which demonstrate promising, although inconsistent, removal of faecal microorganisms. Antimicrobial-producing plants represent a safe, inexpensive yet under-researched biofilter design component that may enhance treatment reliability. The mechanisms underlying plant-mediated microbial removal in biofilters have not been fully elucidated, particularly with respect to antimicrobial production. The aim of this study was therefore to inform biofilter vegetation selection guidelines for optimal pathogen treatment by conducting antimicrobial screening of biofilter-suitable plant species. This involved: (1) selecting native plants suitable for biofilters (17 species) in a Victorian context (southeast Australia); and (2) conducting antimicrobial susceptibility testing of selected plant methanolic extracts (≥ 5 biological replicates/species; 86 total) against reference stormwater faecal bacteria (Salmonella enterica subsp. enterica ser. Typhimurium, Enterococcus faecalis and Escherichia coli).

RESULTS

The present study represents the first report on the inhibitory activity of polar alcoholic extracts from multiple tested species. Extracts of plants in the Myrtaceae family, reputed for their production of antimicrobial oils, demonstrated significantly lower minimum inhibitory concentrations (MICs) than non-myrtaceous candidates (p < 0.0001). Melaleuca fulgens (median MIC: 8 mg/mL; range: [4-16 mg/mL]), Callistemon viminalis (16 mg/mL, [2-16 mg/mL]) and Leptospermum lanigerum (8 mg/mL, [4-16 mg/mL]) exhibited the strongest inhibitory activity against the selected bacteria (p < 0.05 compared to each tested non-myrtaceous candidate). In contrast, the Australian biofilter gold standard Carex appressa demonstrated eight-fold lower activity than the highest performer M. fulgens (64 mg/mL, [32-64 mg/mL]).

CONCLUSION

Our results suggest that myrtaceous plants, particularly M. fulgens, may be more effective than the current vegetation gold standard in mediating antibiosis and thus improving pathogen treatment within biofilters. Further investigation of these plants in biofilter contexts is recommended to refine biofilter vegetation selection guidelines.

Role of serum erythropoietin, erythropoietin-independent erythroid colony formation, and bone marrow assessment in the diagnosis of polycythemia vera in patients with JAK2 V617F mutation

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Background: The discovery of the JAK2 V617F mutation in over 95% of polycythemia vera (PV) patients has led to the development of the new 2008 World Health Organization diagnostic criteria for PV. These specify a requirement for an elevated hemoglobin (Hb, males: >185 g/L, females: >165 g/L) and either evidence of JAK2-mutant cells plus any one of the following minor criteria: a below normal level of serum erythropoietin (Epo), detectable Epo-independent erythroid colony (EEC) formation in vitro, or panmyelosis in the bone marrow, or two of the latter in the absence of detectable JAK2-mutant cells. However, in patients with an elevated Hb and JAK2V617F positivity, there are few data to determine whether any of the 3 minor criteria actually add an independent contribution to the diagnosis of PV. Methods: We performed a retrospective chart review of 77 patients who had an elevated Hb and were positive for the JAK2 V617F mutation and who also had a test for at least one of the 3 minor criteria (serum Epo level: n = 53; EEC formation: n = 66; bone marrow examination: n = 16) to determine the frequency of cases who might lack one or more of these. Results: Although the number of patients with a complete set of data was limited, the results, nevertheless, were sufficient to show that all 3 minor criteria were highly represented and all 77 of the patients analyzed (100%) were positive for at least one of them; i.e., 47 of 53 tested (89%) had a reduced serum Epo level; 65 of 66 tested (98%) had EECs and 15 of 16 tested (94%) had evidence of bone marrow panmyelosis. Conclusions: Neither the Epo level, nor the presence of EECs nor evidence of bone marrow panmyelosis provided additional diagnostic specificity in a population of 77 patients with both JAK2 V617F-positive cells and an elevated Hb. Consideration should be given to limiting serum Epo, EEC, and bone marrow assessments to JAK2 mutant-negative patients.

No significant financial relationships to disclose.

Improved survival in HIV-associated diffuse large B-cell lymphoma with the addition of rituximab to chemotherapy in patients receiving highly active antiretroviral therapy

PURPOSE

Recent trials suggest serious toxicity in HIV-associated non-Hodgkin's lymphoma (NHL) with rituximab (R) and chemotherapy (CT), offsetting the benefit of rituximab.

METHOD

We retrospectively reviewed experience with CHOP-R vs. CT in 40 patients with HIV-associated diffuse large B-cell lymphoma (DLBCL) diagnosed between December 1992 and February 2006, all of whom were treated with curative intent.

RESULTS

In a univariate analysis, International Prognostic Index (IPI) score, prior AIDS, HAART, and rituximab were significant for overall survival (OS). In a multivariate analysis, IPI 0-1 (p < .02), no prior AIDS (p < .0002), and receiving CHOP-R (p < .01) were significant for improved OS, and HAART use (p < .09) retained a trend for improved OS. The hazard ratio (HR) for patients with high IPI receiving CHOP-R was 0.3 (95% CI 0.1-0.8). Patients without prior AIDS receiving CHOP-R had an HR of 0.5 (95% CI 0.1-1.7). The OS at 30 months in patients not receiving HAART was 0%. With HAART, OS was 33% for CT and 86% for CHOP-R; HR for CHOP-R was 0.4 (95% CI 0.1-1.2). Toxic deaths were 3 (33%) for CHOP-R and 6 (25%) for CT (p = ns); all toxic deaths with CHOP-R were in patients not receiving HAART. Rituximab-treated patients had a lower death rate from lymphoma (CHOP-R, 2 [16%] vs. CT, 15 [63%]; p < .04), and overall mortality (CHOP-R, 5 [42%] vs. CT, 21 [88%]; p < .01).

CONCLUSION

These retrospective data suggest that fatal toxicity of rituximab in HIV-NHL is not increased provided HAART is used, that the addition of rituximab to CT improved outcome, and that further prospective trials investigating this issue are warranted.

Ten year retrospective analysis of BOP (bleomycin, vincristine, predinisone)—A novel non-myelosuppressive chemotherapy regimen for treatment of non-Hodgkin’s lymphoma

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Background: Non-Hodgkin’s Lymphoma (NHL) represents the most common hematological malignancy in North America. Patients with advanced NHL, particularly those with pancytopenia, often do not tolerate the myelosuppressive side effects of chemotherapy. BOP (Bleomycin 10 mg/m2 IV D1, Vincristine 1.4 mg/m2 (max 2 mg) D1 and Prednisone 100 mg PO on D1,3,5,) q weekly ± Rituximab 375 mg/m2 IV D1 has been used as a non-myelosuppressive chemotherapy regimen for patients with advanced NHL at the Cancer Centre of Southeastern Ontario (CCSEO). Methods: This was a retrospective chart review of patients with NHL who have been treated with ≥1 cycle of BOP ± R at the CCSEO in the last 10 years. Primary endpoints included an assessment of patient demographics, clinical setting, clinical response, survival and toxicity. Results: Eighty-two patients were treated with BOP ± R (71 BOP, 11 R-BOP). The patient population was 59% male and 80% stage ≥3. The most common histology was Diffuse Large B cell Lymphoma (22%) and Follicular Lymphoma (19.5%). Eighty percent of patients had an IPI score ≥2. The median number of chemotherapy treatments prior to BOP was 2. Overall, the response rate (CR + PR) was 46.3% with a mean duration of response of 4.6 months. Median survival was 3.8 years. BOP was used successfully as a salvage regimen prior to stem cell transplant in three patients and as a first line treatment prior to myelosuppressive treatment in 19 patients. The regimen was generally well tolerated with no hematologic toxicity or infectious complication. Four patients experienced mild pulmonary toxicity. There were no deaths attributable to drug toxicity. Response rates and toxicities in the R-BOP population were not significantly different from those of BOP. Conclusions: Patients with advanced poor prognosis NHL have a favorable response rate associated with minimal toxicity to the non-myelosuppressive chemotherapy regimen BOP ± R.

No significant financial relationships to disclose.

Managed care for uninsured patients at an academic health center: a case study

In 1997, the University of New Mexico Health Sciences Center ("the Center") created a managed care plan ("the Plan") for its uninsured patients who were county residents. The Plan's features include pooling the resources of existing county safety-net providers, enrolling patients with primary care providers at easily accessible neighborhood-based clinics, and investing in social support services, case management, and 24-hour telephone triage. After two years of the Plan's operation, the utilization of ambulatory care services by Plan enrollees, the number of discharges per 1,000 enrollees from the Center-affiliated University Hospital, and the number of hospital days per 1,000 enrollees had all dropped significantly (p < .001 for all). For the 13,114 enrollees in the Plan, University Hospital saved an estimated $1,904,872 per year in costs. The replacement of unpaid hospital days with paying patients is estimated to have yielded over $695,000 in additional revenues per year. The authors conclude that managing the care of uninsured patients in an academic health center can reduce ambulatory care and inpatient utilization and reduce the cost of care. To achieve these favorable outcomes requires the organization of services to meet the unique needs of the uninsured and underserved population.

Fostering the health of communities: a unifying mission for the University of New Mexico Health Sciences Center

Fostering the health of communities can serve as a unifying mission of the academic health center (AHC), which can set the AHC apart from other health providers in the community. To achieve this mission, the University of New Mexico's AHC is increasingly focusing education, research, and service upon the identified health and service needs of communities in its state. Since major health problems in our society have social, behavioral, and economic roots, New Mexico's AHC has tapped into the broad expertise of its different components as well as that of its state and community partners to adequately address health problems in the community. Its hospitals offer financing and management resources, its colleges offer innovative approaches to community-based education, and the state department of health offers expertise in health policy development. To adequately respond to the complexity of community health needs, the different colleges and departments at New Mexico's AHC are increasingly merging into integrated governance units. Measures of community outreach success include evidence of strengthened community development, increased health care access, and improved indices of community health. New Mexico's AHC formed an interdisciplinary rural outreach task force, which has demonstrated its ability to form partnerships with state and local agencies and to mobilize institutional resources in education, research, and service from the AHC's different departments, colleges, and hospitals to respond promptly to unique community health needs. Evidence shows that such an integrated, coordinated AHC intervention can generate strong and lasting AHC-community alliances, improve the quality and economic viability of community health systems, and enhance the financial resources of the AHC.

Absence of allelic loss on chromosome 5q by RFLP analysis in preleukemia

Thirty-eight patients with various forms of myelodysplastic syndrome (MDS) were studied for the loss of restriction fragment length polymorphism (RFLP) heterozygosity on chromosome 5q as inferential support for the presence of a growth regulatory locus in this area of the genome. Conventional chromosomal analysis was performed in addition to RFLP studies of constitutive and granulocyte DNA using five polymorphisms from chromosome 5. Allelic loss in granulocyte DNA was identified in only one patient in whom monosomy 5 had already been defined cytogenetically. These results suggest that DNA sequence loss from chromosome 5q other than that observed cytogenetically is a rare event in MDS. Thus the potential involvement of a growth regulatory gene(s), from this area of the genome, in the leukemogenic process most likely involves a more subtle genetic change.

Diverticular complications of renal failure

Ten patients with chronic renal failure presented with complications of colonic diverticula. Five had acute diverticulitis, 4 perforated diverticula, and 1 lower gastrointestinal hemorrhage. Symptoms were less severe than expected. In 3 the diagnosis was first suspected when free intra-abdominal air was detected. Seven patients had laparotomy, 5 emergently. Radiologists should be aware of the potential for diverticular complication in patients with renal failure, even with minimal or absent symptoms. Suspicion of colonic pathology either clinically or radiographically should be evaluated promptly so that aggressive therapy can begin.

Studies of human natural killer cells. III. Neutropenia associated with unusual characteristics of antibody-dependent and natural killer cell-mediated cytotoxicity

A 52-year-old Caucasian man with chronic neutropenia and recurrent infections was found to have an increased proportion of peripheral T lymphocytes having Fc receptors for IgG (T gamma ). Although levels of antibody-dependent cell-mediated cytotoxicity (ADCC) and "natural" killing (NK) by unfractionated lymphocytes were similar to those of a control donor, the frequency of KN cells was markedly increased. Removal of E rosette-forming cells eliminated both NK and ADCC by the patient's peripheral blood, in marked contrast to the enhanced cytotoxicity seen with control lymphocytes. Both normal and patient ADCC and NK functions were removed by depletion of Fc receptor-bearing cells. These depletion experiments proved that all of the patient's killer cells were E rosette-forming T gamma cells, in contrast to the heterogeneous pattern of null gamma and T gamma killer cells seen in the blood of normal donors. The homogeneity of the T gamma proliferation suggested that ADCC and NK were mediated by the same cell type, albeit acting by different mechanisms. The addition of the patient's serum and lymphocytes to chromium-labelled normal granulocytes caused a low but significant level of cytotoxicity, indicating that the patient's neutropenia may have been caused by a similar mechanism in vivo. There was no evidence of complement-dependent serum antibody-mediated neutrophil lysis, but one serum sample taken over the course of the patient's disease agglutinated granulocytes from four of five donors tested.