Advance Care Planning and Palliative Care Consultation in Kidney Transplantation

RATIONALE & OBJECTIVE

Because of the high risk of waitlist mortality and posttransplant complications, kidney transplant (KT) patients may benefit from advance care planning (ACP) and palliative care consultation (PCC). We quantified the prevalence and racial disparities in ACP and PCC among KT candidates and recipients.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

2,575 adult KT candidates and 1,233 adult recipients (2008-2020).

EXPOSURE

Race and ethnicity.

OUTCOMES

All reports of ACP and PCC were abstracted from chart review. ACP was defined as patient self-report of an advance directive, presence of an advance directive in the medical record, or a documented goals-of-care conversation with a provider. PCC was defined as an ordered referral or a documented palliative care note in the medical record.

ANALYTICAL APPROACH

Racial/ethnic disparities in ACP/PCC were estimated using adjusted logistic regression.

RESULTS

21.4% of KT candidates and 34.9% of recipients engaged in ACP. There were racial/ethnic disparities in ACP among KT candidates (White, 24.4%; Black, 19.1%; Hispanic, 15%; other race and ethnicity, 21.1%; P=0.008) and recipients (White, 39.5%; Black, 31.2%; Hispanic, 26.3%; other race and ethnicity, 26.6%; P=0.007). After adjustment, Black KT recipients had a 29% lower likelihood of engaging in ACP (OR, 0.71; 95% CI, 0.55-0.91) than White KT recipients. Among older (aged≥65 years) recipients, those who were Black had a lower likelihood of engaging in ACP, but there was no racial disparity among younger recipients (P=0.020 for interaction). 4.2% of KT candidates and 5.1% of KT recipients engaged in PCC; there were no racial disparities in PCC among KT candidates (White, 5.3%; Black, 3.6%; Hispanic, 2.5%; other race and ethnicity, 2.1%; P=0.13) or recipients (White, 5.5%; Black, 5.6%; Hispanic, 0.0%; other race and ethnicity, 1.3%; P = 0.21).

LIMITATIONS

Generalizability may be limited to academic transplant centers.

CONCLUSIONS

ACP is not common among KT patients, and minoritized transplant patients are least likely to engage in ACP; PCC is less common. Future efforts should aim to integrate ACP and PCC into the KT process.

PLAIN-LANGUAGE SUMMARY

Kidney transplant (KT) candidates and recipients are at elevated risk of morbidity and mortality. They may benefit from completing a document or conversation with their palliative care provider that outlines their future health care wishes, known as advance care planning (ACP), which is a component of palliative care consultation (PCC). We wanted to determine how many KT candidates and recipients have engaged in ACP or PCC and identify potential racial disparities. We found that 21.4% of candidates and 34.9% of recipients engaged in ACP. After adjustment, Black recipients had a 29% lower likelihood of engaging in ACP. We found that 4.2% of KT candidates and 5.1% of KT recipients engaged in PCC, with no racial disparities found in PCC.

"They Would Lift My Spirits": Sources of Support for Family Surrogate Decision-Makers at the End of Life

Surrogate decision-makers make critical decisions for loved ones at the end of life, and some experience lasting negative psychological outcomes. Understanding whom they rely on for support and the types of support they value may inform nursing care and that of other health team members who work with surrogates. The purpose of the study was to explore decision support and other types of support provided to surrogate decision-makers at the end of life of their loved one and perceived usefulness of the support. This secondary analysis of data from a mixed-methods study involved the examination of the transcripts of qualitative interviews with 13 surrogate decision-makers in the United States, conducted between 2010 and 2014. A constant comparative method was used to identify common themes surrounding surrogate decision support at the end of life. Surrogates valued advance directives and conversations with their loved one about treatment preferences. Surrogates described involving many different types of people in decision-making and other types of support. Finally, surrogates appreciated being reassured that they were doing a good job in making decisions and seemed to seek out this type of affirmation from various sources including the health care team, family, and friends. Nurses are well-positioned to provide this affirmation because of the time that they spend caring for the patient and family. Future research should further explore the concept of affirmation of surrogates in their role as a means of support as they make decisions for a loved one.

A retrospective 'real-world' cohort study of azole therapeutic drug monitoring and evolution of antifungal resistance in cystic fibrosis

BACKGROUND

Individuals with cystic fibrosis (CF) have an increased susceptibility to fungal infection/allergy, with triazoles often used as first-line therapy. Therapeutic drug monitoring (TDM) is essential due to significant pharmacokinetic variability and the recent emergence of triazole resistance worldwide.

OBJECTIVES

In this retrospective study we analysed the 'real-world' TDM of azole therapy in a large CF cohort, risk factors for subtherapeutic dosing, and the emergence of azole resistance.

METHODS

All adults with CF on azole therapy in a large single UK centre were included. Clinical demographics, TDM and microbiology were analysed over a 2 year study period (2015-17) with multivariate logistic regression used to identify risk factors for subtherapeutic dosing.

RESULTS

91 adults were treated with azole medication during the study period. A high prevalence of chronic subtherapeutic azole dosing was seen with voriconazole (60.8%) and itraconazole capsule (59.6%) use, representing significant risk factors for subtherapeutic levels. Rapid emergence of azole resistance was additionally seen over the follow-up period with a 21.4% probability of CF patients developing a resistant fungal isolate after 2 years. No significant relationship was found however between subtherapeutic azole dosing and azole resistance emergence.

CONCLUSIONS

Our study demonstrates a high prevalence of subtherapeutic azole levels in CF adults with increased risk using itraconazole capsules and voriconazole therapy. We show rapid emergence of azole resistance highlighting the need for effective antifungal stewardship. Further large longitudinal studies are needed to understand the effects of antifungal resistance on outcome in CF and the implications of subtherapeutic dosing on resistance evolution.

Genomic epidemiology of the emerging pathogen Batrachochytrium dendrobatidis from native and invasive amphibian species in Chile

Emerging fungal diseases represent a threat to food security, animal and human health worldwide. Amphibian chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), has been associated with catastrophic and well-documented amphibian population declines and extinctions. For the first time, Bd was cultured from native and non-native wild amphibians in Chile. Phylogenomic analyses revealed that Chilean isolates AVS2, AVS4 and AVS7 group within the global panzootic lineage of Bd (BdGPL) in a single highly supported clade that includes a genotype previously isolated from the United Kingdom. Our results extend the known distribution of BdGPL in South America and suggest a single and relatively recent introduction of BdGPL into the country, providing additional support to the role of anthropogenic activity in the global spread of this panzootic lineage.

Wildlife disease. Recent introduction of a chytrid fungus endangers Western Palearctic salamanders

Emerging infectious diseases are reducing biodiversity on a global scale. Recently, the emergence of the chytrid fungus Batrachochytrium salamandrivorans resulted in rapid declines in populations of European fire salamanders. Here, we screened more than 5000 amphibians from across four continents and combined experimental assessment of pathogenicity with phylogenetic methods to estimate the threat that this infection poses to amphibian diversity. Results show that B. salamandrivorans is restricted to, but highly pathogenic for, salamanders and newts (Urodela). The pathogen likely originated and remained in coexistence with a clade of salamander hosts for millions of years in Asia. As a result of globalization and lack of biosecurity, it has recently been introduced into naïve European amphibian populations, where it is currently causing biodiversity loss.

Speciation despite globally overlapping distributions in Penicillium chrysogenum: the population genetics of Alexander Fleming's lucky fungus

Eighty years ago, Alexander Fleming described the antibiotic effects of a fungus that had contaminated his bacterial culture, kick starting the antimicrobial revolution. The fungus was later ascribed to a putatively globally distributed asexual species, Penicillium chrysogenum. Recently, the species has been shown to be genetically diverse, and possess mating-type genes. Here, phylogenetic and population genetic analyses show that this apparently ubiquitous fungus is actually composed of at least two genetically distinct species with only slight differences detected in physiology. We found each species in air and dust samples collected in and around St Mary's Hospital where Fleming worked. Genotyping of 30 markers across the genome showed that preserved fungal material from Fleming's laboratory was nearly identical to derived strains currently in culture collections and in the same distinct species as a wild progenitor strain of current penicillin producing industrial strains rather than the type species P. chrysogenum. Global samples of the two most common species were found to possess mating-type genes in a near 1:1 ratio, and show evidence of recombination with little geographic population subdivision evident. However, no hybridization was detected between the species despite an estimated time of divergence of less than 1MYA. Growth studies showed significant interspecific inhibition by P. chrysogenum of the other common species, suggesting that competition may facilitate species maintenance despite globally overlapping distributions. Results highlight under-recognized diversity even among the best-known fungal groups and the potential for speciation despite overlapping distribution.

The COX-2 inhibitor market withdrawals and prescribing patterns by rheumatologists in patients with gastrointestinal and cardiovascular risk

OBJECTIVE

To examine effects of the COX-2 inhibitor market withdrawals on NSAID utilization among patients at increased risk of gastrointestinal (GI) and cardiovascular (CV) toxicities.

METHODS

A prospective cohort study was conducted using patients enrolled in the Consortium of Rheumatology Researchers of North America (CORRONA) Registry. The study population included rheumatoid arthritis (RA) and psoriatic arthritis (PsA) patients prescribed NSAIDs by rheumatologists from 1/1/2003 to 12/31/2005. Three cohorts were defined based on calendar year. The primary outcome assessed whether or not an NSAID gastroprotective strategy was prescribed. Secondary outcomes included rates of COX-2 inhibitor utilization and gastroprotective co-therapy utilization, stratified by the presence of cardiac and GI risk factors.

RESULTS

NSAID gastroprotection utilization decreased from 65.1% in 2003 to 47.7% (p<0.001) in 2005. COX-2 inhibitor use decreased from 55.1% to 29.2% (p<0.001), whereas nonselective NSAIDs (nsNSAIDs) use increased from 50.2% to 73.9% (p=<0.01). Among patients with two or more risk factors for NSAID related GI bleeding, gastroprotection decreased from 74.4% in 2003 to 60.9% (p<0.01). For patients with two or more CV risk factors from 2003 to 2005, COX-2 inhibitor utilization decreased significantly, whereas nsNSAID utilization increased significantly.

CONCLUSIONS

The COX-2 inhibitor withdrawals resulted in a rapid decline in NSAID gastroprotection prescribed by participating U.S. rheumatologists despite the availability of other gastroprotective options. Channeling toward nsNSAID use was widespread, including among patients at increased CV risk. Longer term follow-up is required to determine the clinical significance of these changes in NSAID prescribing, particularly for NSAID-related GI and CV-related toxicities.

Non-invasive sampling methods for the detection of Batrachochytrium dendrobatidis in archived amphibians

Chytridiomycosis, an emerging infectious disease of amphibians caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), is associated with amphibian population declines worldwide. Investigation of the origin and spread of the pathogen requires examination of archived museum specimens of amphibians. Examination for Bd infection is usually done using histological techniques, which are often too destructive for valuable museum material. Three alternative methods for Bd detection (skin swabbing, brushing and scraping) were evaluated for ability to yield Bd DNA and destructiveness to specimens. Archived amphibians known to be Bd positive and which had been preserved in either formalin or ethanol for many years were used. Samples were analysed using a Bd-specific quantitative real-time Taqman PCR (qPCR) assay. There was no difference in the ability of each of the techniques to detect Bd infection, with the pathogen being detected in 75 to 81% of the 16 ethanol-fixed frogs examined. Visible evidence of sampling was left by scraping, but not by swabbing or brushing. The brush-qPCR technique detected higher counts of genomic equivalents than the other 2 sampling methods, although differences were not statistically significant. The qPCR assay did not detect Bd from any of the 6 formalin-fixed frogs examined, regardless of the sampling method. Nondestructive sampling techniques enable qPCR analysis of ethanol-preserved museum specimens for Bd. Recently, the incorporation of DNA cleanup steps allowed the detection of Bd in destructively sampled tissues from formalin preserved specimens. Further studies using nondestructive sampling incorporating DNA cleanup steps for the detection of Bd in formalin preserved specimens are warranted.

Using itraconazole to clear Batrachochytrium dendrobatidis infection, and subsequent depigmentation of Alytes muletensis tadpoles

Batrachochytrium dendrobatidis (Bd) is a global threat to amphibian biodiversity. Current calls for conservation through captive breeding require that efficient and reliable antifungal treatments be developed for target species. Here we confirm that the antifungal itraconazole is an effective treatment for infection in larval Alytes muletensis. Exceptionally low doses applied as few as 7 times were effective at clearing infection from tadpoles for up to 28 d after treatment. However, we cannot recommend itraconazole as a treatment for this species as depigmentation of tadpoles was observed. Further research is required to determine the putative hepatotoxicity of this treatment.

Taxonomic and diagnostic markers for identification of Coccidioides immitis and Coccidioides posadasii

The ribosomal Internal Transcribed Spacer (ITS) regions of the two recognized species of Coccidioides were studied using a reference set of strains that had been previously identified with species defining microsatellite polymorphisms. Unambiguous identification of the two species proved to be possible by amplifying and sequencing the ITS region. PCR-reactions are sensitive to amplification conditions requiring their careful optimization. Stable amplification and sequencing was achieved with primers ITS3 and 4, enabling species diagnosis. Alternatively, Restriction Fragment Length Polymorphism (RFLP) of the entire ITS region using an annealing temperature of 52 degrees C with the restriction enzymes BsrI and XcmI can also distinguish the species. Three strains typifying the species, Glenospora meteuropaea, G. metamericana and Geotrichum louisianoideum, were analyzed and found to be conspecific with C. posadasii. Although these species have nomenclatural priority over C. posadasii, the latter will be proposed for conservation as it has been included in the US select agent list. In addition, Coccidioides immitis is neotypified in this report. Results of antifungal susceptibility testing did not reveal differences between the two species.

The Calyptogena magnifica chemoautotrophic symbiont genome

Chemoautotrophic endosymbionts are the metabolic cornerstone of hydrothermal vent communities, providing invertebrate hosts with nearly all of their nutrition. The Calyptogena magnifica (Bivalvia: Vesicomyidae) symbiont, Candidatus Ruthia magnifica, is the first intracellular sulfur-oxidizing endosymbiont to have its genome sequenced, revealing a suite of metabolic capabilities. The genome encodes major chemoautotrophic pathways as well as pathways for biosynthesis of vitamins, cofactors, and all 20 amino acids required by the clam.

Molecular and phenotypic description of Coccidioides posadasii sp. nov., previously recognized as the non-California population of Coccidioides immitis

Coccidioides posadasii sp. nov., formerly known as non-California (non-CA) Coccidioides immitis, is described. Phylogenetic analyses using single nucleotide polymorphisms, genes, and microsatellites show that C. posadasii represents a divergent, genetically recombining monophyletic clade. Coccidioides posadasii can be distinguished from C. immitis by numerous DNA polymorphisms, and we show how either of two microsatellite loci may be used as diagnostic markers for this species. Growth experiments show that C. posadasii has significantly slower growth rates on high-salt media when compared with C. immitis, suggesting that other phenotypic characters may exist.

The 1999-2000 ACC task analysis of nurse-midwifery/midwifery practice: a consideration of the concept of professional issues

The American College of Nurse-Midwives (ACNM) Certification Council periodically conducts a task analysis study as evidence supporting the content validity of the national certification examination in nurse-midwifery and midwifery. The purpose of this article is to report findings related to the examination of the relationship between professional issues and safe beginning-level midwifery as measured by the 1999-2000 Task Analysis of American Nurse Midwifery and Midwifery Practice. Study findings suggest that newly certified midwives place strong emphasis on the importance of tasks related to the ACNM "Hallmarks of Midwifery," which characterize the art and science of the profession: these include tasks dealing with health promotion and cultural competency. The beginning midwives, however, gave consistently low ratings to tasks related to ACNM "Core Competencies" that mirror the professional responsibilities of midwives; these include tasks related to the history of midwifery, research, or health policy. The study has implications for nurse-midwifery/midwifery educators, experienced midwifery mentors, and other persons interested in reinforcing the relevance of these important professional issues to the new midwife.

Inhibitors of choline uptake and metabolism cause developmental abnormalities in neurulating mouse embryos

BACKGROUND

Choline is an essential nutrient in methylation, acetylcholine and phospholipid biosynthesis, and in cell signaling. The demand by an embryo or fetus for choline may place a pregnant woman and, subsequently, the developing conceptus at risk for choline deficiency.

METHODS

To determine whether a disruption in choline uptake and metabolism results in developmental abnormalities, early somite staged mouse embryos were exposed in vitro to either an inhibitor of choline uptake and metabolism, 2-dimethylaminoethanol (DMAE), or an inhibitor of phosphatidylcholine synthesis, 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET-18-OCH(3)). Cell death following inhibitor exposure was investigated with LysoTracker Red and histology.

RESULTS

Embryos exposed to 250-750 microM DMAE for 26 hr developed craniofacial hypoplasia and open neural tube defects in the forebrain, midbrain, and hindbrain regions. Embryos exposed to 125-275 microM ET-18-OCH(3) exhibited similar defects or expansion of the brain vesicles. ET-18-OCH(3)-affected embryos also had a distended neural tube at the posterior neuropore. Embryonic growth was reduced in embryos treated with either DMAE (375, 500, and 750 microM) or ET-18-OCH(3) (200 and 275 microM). Whole mount staining with LysoTracker Red and histological sections showed increased areas of cell death in embryos treated with 275 microM ET-18-OCH(3) for 6 hr, but there was no evidence of cell death in DMAE-exposed embryos.

CONCLUSIONS

Inhibition of choline uptake and metabolism during neurulation results in growth retardation and developmental defects that affect the neural tube and face.

Nosocomial infections in the neonatal intensive care unit

Nosocomial infections are significant causes of morbidity and mortality in patients who require newborn intensive care. The most common bacterial pathogens are Gram-positive bacteria, including Staphylococcus epidermidis, Staphylococcus aureus, and Enterococcus species. Gram-negative enteric bacilli and Gram-negative environmental bacteria are involved in outbreaks and occasional cases of nosocomial infection. The incidence of fungal infection has increased over the past 10 years; fungemia is the most commonly recognized infection. Surveillance for nosocomial infection is essential to identify outbreaks and detect unsuspected reservoirs of pathogens. A variety of molecular techniques can be used to determine the genetic relatedness of pathogens. Prevention of infection requires the identification of contaminated equipment, education regarding infection control methods including hand washing, and the judicious use of antimicrobial agents.

Biogeographic range expansion into South America by Coccidioides immitis mirrors New World patterns of human migration

Long-distance population dispersal leaves its characteristic signature in genomes, namely, reduced diversity and increased linkage between genetic markers. This signature enables historical patterns of range expansion to be traced. Herein, we use microsatellite loci from the human pathogen Coccidioides immitis to show that genetic diversity in this fungus is geographically partitioned throughout North America. In contrast, analyses of South American C. immitis show that this population is genetically depauperate and was founded from a single North American population centered in Texas. Variances of allele distributions show that South American C. immitis have undergone rapid population growth, consistent with an epidemic increase in postcolonization population size. Herein, we estimate the introduction into South America to have occurred within the last 9,000-140,000 years. This range increase parallels that of Homo sapiens. Because of known associations between Amerindians and this fungus, we suggest that the colonization of South America by C. immitis represents a relatively recent and rapid codispersal of a host and its pathogen.

Predictors of infectious complications after burn injuries in children

BACKGROUND

Infections are the major life-threatening complication of burn injury and occur with the greatest frequency in children. Knowledge of their occurrence and management, however, is extrapolated from studies in adults. We performed a prospective study of infectious complications in burned children.

OBJECTIVE

To delineate epidemiology, risk factors and microbiology of infections in burned children where burn care and surgical interventions are optimal.

METHODS

Children hospitalized for burns were entered into prospective study. Characteristics of the burn injury were assessed, and active surveillance for infections was performed.

RESULTS

Seventy patients were entered [mean age, 42 months; mean total body surface area (TBSA), burn 15%]. Twenty-seven percent of patients developed 39 infections: 13 involved the burn wound (burn wound sepsis, 6; graft loss, 5; and cellulitis, 2); 13 were catheter-associated septicemia; 13 involved other sites (i.e. pneumonia, 4; urinary tract infection, 3; bacteremia, 2; endocarditis, 1; myocardial abscess, 1; toxin-mediated syndrome, 1; and otitis media, 1). Twenty-three infections were caused by a single organism, 9 infections by more than 1 organism and in 7 infections defined by CDC criteria no organism was recovered. Organisms causing infection were: Staphylococcus aureus, 19; Candida albicans, 4; Pseudomonas aeruginosa, 4; coagulase-negative Staphylococcus, 4; Enterococcus sp., 3; Escherichia coli, 1; Klebsiella oxytoca, 1; Serratia marcescens, 1; Streptococcus pneumoniae, 1; Streptococcus pyogenes, 1; Aspergillus fumigatus, 1; and Candida parapsilosis, 1. Burn mechanism (flame and inhalation), extent (TBSA >30%) and depth (full thickness) were risk factors for infection; young age and site of burn were not.

CONCLUSION

The most common infections occurring in burn children are burn wound infections and catheter-associated septicemia. Characteristics of burn injury predict risk of infection. Children with flame and inhalation injury, TBSA burned >30% and full thickness burns are at high risk of infectious complications.

Phylogenetic species recognition and species concepts in fungi

The operational species concept, i.e., the one used to recognize species, is contrasted to the theoretical species concept. A phylogenetic approach to recognize fungal species based on concordance of multiple gene genealogies is compared to those based on morphology and reproductive behavior. Examples where Phylogenetic Species Recognition has been applied to fungi are reviewed and concerns regarding Phylogenetic Species Recognition are discussed.

A test for concordance between the multilocus genealogies of genes and microsatellites in the pathogenic fungus Coccidioides immitis

Uncovering the correct phylogeny of closely related species requires analysis of multiple gene genealogies or, alternatively, genealogies inferred from the multiple alleles found at highly polymorphic loci, such as microsatellites. However, a concern in using microsatellites is that constraints on allele sizes may occur, resulting in homoplasious distributions of alleles, leading to incorrect phylogenies. Seven microsatellites from the pathogenic fungus Coccidioides immitis were sequenced for 20 clinical isolates chosen to represent the known genetic diversity of the pathogen. An organismal phylogeny for C. immitis was inferred from microsatellite-flanking sequence polymorphisms and other restriction fragment length polymorphism-containing loci. Two microsatellite genetic distances were then used to determine phylogenies for C. immitis, and the trees found by these three methods were compared. Congruence between the organismal and microsatellite phylogenies occurred when microsatellite distances were based on simple allele frequency data. However, complex mutation events at some loci made distances based on stepwise mutation models unreliable. Estimates of times of divergence for the two species of C. immitis based on microsatellites were significantly lower than those calculated from flanking sequence, most likely due to constraints on microsatellite allele sizes. Flanking-sequence insertions/deletions significantly decreased the accuracy of genealogical information inferred from microsatellite loci and caused interspecific length homoplasies at one of the seven loci. Our analysis shows that microsatellites are useful phylogenetic markers, although care should be taken to choose loci with appropriate flanking sequences when they are intended for use in evolutionary studies.

Pathogenic clones versus environmentally driven population increase: analysis of an epidemic of the human fungal pathogen Coccidioides immitis

For many pathogenic microbes that utilize mainly asexual modes of reproduction, it is unknown whether epidemics are due to either the emergence of pathogenic clones or environmentally determined increases in the population size of the organism. Descriptions of the genetic structures of epidemic populations, in conjunction with analyses of key environmental variables, are able to distinguish between these competing hypotheses. A major epidemic of coccidioidomycosis (etiologic agent, Coccidioides immitis) occurred between 1991 and 1994 in central California, representing an 11-fold increase above the mean number of cases reported from 1955 to 1990. Molecular analyses showed extensive genetic diversity, a lack of linkage disequilibria, and little phylogenetic structure, demonstrating that a newly pathogenic strain was not responsible for the observed epidemic. Epidemiological analyses showed that morbidity caused by C. immitis was best explained by the interaction between two variables, the lengths of droughts preceding epidemics and the amounts of rainfall. This shows that the principal factors governing this epidemic of C. immitis are environmental and not genetic. An important implication of this result is that the periodicity of cyclical environmental factors regulates the population size of C. immitis and is instrumental in determining the size of epidemics. This knowledge provides an important tool for predicting outbreaks of this pathogen, as well as a general framework that may be applied to determine the causes of epidemics of other fungal diseases.

Inferring infection processes of a parasitic nematode using population genetics

The distribution of genetic differentiation in a population of the parasitic nematode Strongyloides ratti divided between rat hosts was determined. We applied population genetic theory to these data to determine the source of new infections. We estimate the rate at which a rat acquires a new infection from (a) the existing subpopulation of parasites within that rat ('self-reinfection') versus (b) the wider environment ('immigration'). We find that the observed levels of genetic diversity and differentiation in the study population are consistent with low to moderate rates of self-reinfection and inconsistent with high rates of self-reinfection.

THE EVOLUTION OF ASEXUAL FUNGI: Reproduction, Speciation and Classification

Phylogenetic and population genetic methods that compare nucleic acid variation are being used to identify species and populations of pathogenic fungi and determine how they reproduce in nature. These studies show that asexual or sexual reproductive morphology does not necessarily correlate with clonal or recombining reproductive behavior, and that fungi with all types of reproductive morphologies and behaviors can be accommodated by a phylogenetic species concept. Although approximately one fifth of described fungi have been thought to be asexual and clonal, recent studies have shown that they are also recombining. Whether a particular pathogen reproduces clonally or by recombination depends on factors relating to its biology and its distribution in space and time. Knowing the identity of species and populations and their reproductive modes, while taking a broad view of pathogen behavior in space and time, should enhance the ability of pathologists to control pathogens and even predict their behavior.

Metabolism during delayed hatching in terrestrial eggs of a marine fish, the grunion Leuresthes tenuis

California grunion, Leuresthes tenuis (Osteichthyes: Atherinidae), leave the ocean to spawn in the sand following extreme high tides in summer. Eggs develop out of water and are able to hatch within 9-13 d, the primary hatching period. Eggs hatch on immersion and agitation by waves at the next extreme high-tide series. However, if the waves do not reach them and hatching is not induced, eggs remain viable in the sand for several weeks. During this period, grunion eggs will delay hatching, but will hatch at any time if immersed and agitated in seawater. Egg metabolism during embryonic development was measured by aerial respirometry. Metabolism increased linearly until the first date at which eggs were able to hatch. At that time, metabolic rate stabilized and remained constant for two additional weeks of embryonic incubation. Larvae induced to hatch after different durations of incubation within this period were not significantly different in length; however, the amount of oil contained in the yolk decreased linearly during the delayed hatching period. We suggest that the increase in grunion egg metabolism during the time to primary hatching capability, and the steady, high metabolic rate throughout the delayed hatching period, permit reproduction in the unique niche of these marine eggs. These semiterrestrial anamniotic eggs develop quickly and remain continuously ready to hatch over an extended period in response to an environmentally dependent and somewhat unpredictable embryonic timetable.

The population genetic structure of the facultatively sexual parasitic nematode Strongyloides ratti in wild rats

We have investigated the population genetic structure of the parasitic nematode Strongyloides ratti in wild rats. In the UK, S. ratti reproduces predominantly by mitotic parthenogenesis, with sexual forms present at a rate of less than 1%. S. ratti was found to be a prevalent parasite and substantial genetic diversity was detected. Most rats were infected with a genotypic mixture of parasites. A hierarchical analysis of the genetic variation found in S. ratti sampled across Britain and Germany showed that 73.3% was explained by variation between parasites within individual hosts and 25.3% by variation between rats within sample sites. Only a small proportion (1.4%) of the total genetic variation was attributable to genetic subdivision between sample sites, suggesting that there is substantial gene flow between these sites. Most parasites sampled were found to exist in Hardy-Weinberg equilibrium and this population genetic structure is discussed in view of the virtual absence of sexual reproduction.

In vitro susceptibility testing of topical antimicrobial agents used in pediatric burn patients: comparison of two methods

One hundred and seventy-seven bacterial isolates obtained from pediatric burn victims were tested for in vitro susceptibility against bacitracin, silver sulfadiazine, mafenide acetate, nitrofurazone, and mupirocin by two methods: standard microbroth dilution and Nathan's agar well diffusion (NAWD). Nitrofurazone had the broadest spectrum of activity. Mupirocin was the most potent agent against methicillin-susceptible Staphylococcus aureus. Silver sulfadiazine showed activity against gram-positive organisms and higher minimum inhibitory concentration (MIC) values, and smaller zone sizes were seen for methicillin-resistant S. aureus and gram-negative bacilli. Bacitracin showed activity against S. aureus and Streptococcus pyogenes by the microbroth method; activity could not be assessed by NAWD. Mafenide acetate had the highest MICs for all isolates tested. Correlation between methods for all isolates tested was best for mupirocin and nitrofurazone. NAWD was labor intensive and difficult to interpret; MIC method was easy to perform and reproducible. Clinical correlation is necessary to establish breakpoints for interpretation of test results.

Study of antibiotic prophylaxis during burn wound debridement in children

Twenty-three children completed a randomized, prospective, partially blinded study performed to assess the need and effectiveness of antibiotic prophylaxis at the time of burn wound debridement and grafting. Patients with a total body surface area (TBSA) burn less than 35% were randomized to receive cefazolin or placebo. Patients with burns of 35% or more TBSA were randomized to receive cefazolin or targeted antibiotics based on surveillance cultures. Blood cultures were obtained at commencement, immediately after, and 24 hours after surgical debridement. Quantitative cultures and histologic examination of biopsied burn wounds were performed. Burn wound infection occurred in three patients with burns of less than 35% TBSA, two in the cefazolin group and one in the placebo group. Quantitative tissue cultures and histologic examination did not predict either infection. During the four procedures in three patients with 35% or more TBSA, three were randomized to receive cefazolin, and one targeted antibiotics. All receiving cefazolin developed burn wound infection. Quantitative tissue culture was more than 10(5) colony-forming units per gram in all, whereas histologic examination was positive in one. In our patients with less than 35% burn, cefazolin was not necessary, and in those with 35% or more burn, it was not effective.

Levamisole effects on major histocompatibility complex and adhesion molecule expression and on myeloid cell adhesion to human colon tumor cell lines

BACKGROUND

The drug levamisole has been successfully used in combination with fluorouracil to increase the disease-free interval and survival of patients who have undergone surgical resection of Dukes' stage C colon cancer. Levamisole is thought to affect the host immune response. Several recent studies have examined its effect on the expression of major histocompatibility complex (MHC) class I molecules, but the results have been inconsistent. An equally important requirement for a host cellular immune response is the adhesion of leukocytes to tumor cells. The latter may be required for cell-mediated antitumor cytotoxic responses.

PURPOSE

We evaluated the ability of levamisole to affect the expression of MHC class I molecules and cell-adhesion molecules and determined whether levamisole could affect leukocyte adhesion to tumor cells that had been treated with the drug.

METHODS

A panel of four human colon tumor cell lines (HT-29, SW-620, HCT-15, and LoVo), A-375 human melanoma cells, and human umbilical vein endothelial cells (HUVEC) were cultured in the presence of levamisole and examined by solid-phase enzyme immunoassay to determine the level of expression of MHC class I, intercellular adhesion molecule 1 (ICAM-1), vascular cell-adhesion molecule-1 (VCAM-1), leukocyte integrin VLA-4, and lymphocyte-functional antigen (LFA-1) molecules. Adhesion of HL-60 and THP-1 myeloid cells to tumor cells was also evaluated. Tumor necrosis factor (TNF) at 10 ng/mL was used as a positive control for increasing adhesion molecule expression and cell-cell adhesion. The statistical significance of differences in cell surface molecule expression and functional adhesion between treated and control cells were tested by use of analysis of variance and the two-tailed Dunnett's test.

RESULTS

Treatment with levamisole (0.1 and 1 micrograms/mL) caused the levels of MHC class I expression to increase approximately threefold above control levels on HCT-15 and LoVo colon tumor cells (P < .05 in each case) compared with untreated cells, caused minimal increases on HT-29 cells (to 1.5 times control levels), but caused no significant increases on SW-620 colon tumor or A-375 melanoma cells. The HCT-15 and LoVo colon tumor cells had very low basal MHC expression Levamisole (1 micrograms/mL) increased VCAM-1 expression on HT-29 and SW-620 colon tumor cells to 4.3 and 2.4 times (P < .05 in each case) control levels, respectively, doubled ICAM-1 expression on HT-29 cells (P < .05), and increased LFA-1 expression on HT-29, LoVo, and A-375 cells to 2.1, 3.2, and 1.8 (P < .05 in each case) times control levels, respectively. TNF (10 ng/mL) was used as a positive control and yielded increased expression of MHC class I molecules on the HT-29, LoVo, SW-620, and HCT-15 cells (2.5, 7.8, 1.9, and 4.8 times control levels, respectively; P < .05 in each case). TNF increased VCAM-1 expression to 4.2 times the vehicle-treated control levels (P < .05) on HT-29 cells and increased ICAM-1 expression on HT-29, LoVo, and SW-620 cells (8.4, 1.8, and 1.9 times vehicle control levels, respectively; P < .05 in each case). THP-1 and HL-60 cells demonstrated increased adhesion to levamisole-treated HT-29 colon tumor cells. HL-60 cells also exhibited increased levamisole-mediated adherence to LoVo and HCT-15 cells. Adherence by THP-1 was significantly improved after levamisole treatment of the HUVEC, SW-620, and A-375 cells (P < .05 in each case).

CONCLUSIONS

Levamisole can directly affect the expression and function of molecules that are engaged in cell-cell recognition and signaling on the surfaces of some tumor cell lines. However, no consistent pattern between cell-adhesion molecule expression, cell-cell adhesion, or levamisole concentration could be discerned.

Effect of rifampin on Staphylococcus aureus colonization in children on chronic peritoneal dialysis

The efficacy of rifampin in eliminating Staphylococcus aureus colonization was evaluated in a pediatric peritoneal dialysis population. Six children with documented nasal colonization were treated for 7 days with rifampin and cloxacillin. Although antimicrobial therapy eliminated nasal carriage in all patients, recolonization occurred in 66%. Exit site colonization proved difficult to eradicate with negative cultures documented in only 3 of 5 children after rifampin/cloxacillin therapy. Although S. aureus carriage is a risk factor for S. aureus infections, efforts to eradicate carriage with rifampin are hindered by rapid recolonization.

Cerebrospinal fluid analysis in systemically ill children without central nervous system disease

OBJECTIVE

Experience led us to question the applicability of standards for normal cerebrospinal fluid (CSF), originally developed in healthy children, to children with systemic illness but without central nervous system (CNS) infection. The purpose of this study was to test our hypothesis that systemically ill children, in the absence of CNS infection, have an elevated CSF white blood cell count and a greater percentage of neutrophils than accepted norms.

METHODS

We enrolled 345 patients in the following diagnostic categories: infants 1 month of age or younger with possible sepsis (n = 95), patients older than 1 month of age with possible sepsis (n = 155), patients with a focus of infection in close proximity to the CNS (n = 51), and patients presenting with seizures and fevers (n = 45). Sociodemographic data and results of CSF examination were abstracted from the medical records. Statistical analysis systems were used for data processing.

RESULTS

The CSF white blood cell count did not significantly differ from standards except for a lower mean count in the group presenting with seizures. The percent of CSF neutrophils was significantly greater than standards, however, for those patients older than 1 month of age with possible sepsis, those with a focus of infection in close proximity to the CNS, and those presenting with seizures. Data analysis by quantiles shows only 25% to 50% of patients, in each of the diagnostic categories, meeting the current definition of normal CSF neutrophil count.

CONCLUSIONS

Our results show that a mean of at least 5% neutrophils may be present in the CSF with a diagnosis of fever without a source, a focus of infection in close proximity to the CNS, or a seizure with fever in the absence of CNS infection. These data support tailoring treatment based on clinical assessment rather than what is considered an abnormal CSF neutrophil count by current standards.

Recovery of Pseudomonas cepacia and other Pseudomonas species from the environment

Nine hundred sixteen cultures were obtained from homes of patients with cystic fibrosis, control homes, salad bars, and food markets, and analyzed for the presence of Pseudomonas cepacia and related bacteria. P cepacia was recovered from 5 (18%) of 27 homes, and from 20 (4%) of 509 cultures collected outside of homes. Relative to other pseudomonads, P cepacia is found infrequently in the environment. It is not clear how frequently these sources contribute to acquisition of this bacteria by persons with cystic fibrosis.

Quantitative skin cultures at potential catheter sites in neonates

OBJECTIVE

To identify and quantify the bacterial and fungal flora present at body sites used for vascular catheterization of infants in a neonatal intensive care unit.

DESIGN

Quantitative skin cultures were obtained from a group of neonatal patients to determine the bacterial flora found on the skin at four sites. Quantitative cultures of the jugular, subclavian, umbilical, and femoral sites were obtained on 50 infants, ranging in age from 2 days to 3 months old.

SETTING

The neonatal intensive care unit of St. Christopher's Hospital for Children, a university-affiliated tertiary care children's hospital.

RESULTS

Colony counts ranged from 0 to 10(6) colony-forming units/10 cm2. Types of organisms found were consistent with other published studies and included coagulase-negative staphylococci, Staphylococcus aureus, yeast, aerobic gram-negative rods, Enterococcus species, Corynebacterium species, and alpha-hemolytic streptococci. There was a significantly higher mean colony count at the combined jugular/femoral sites versus the subclavian site (P < 0.01) and umbilical site (P < 0.05). Mean colony counts did not differ significantly between the jugular and femoral site, or between the subclavian and umbilical site. The umbilical site was more likely to be colonized with aerobic gram-negative rods, Enterococcus species, and yeast, while the subclavian had coagulase-negative staphylococci as the predominant organism. The jugular and femoral sites demonstrated a higher colony count of aerobic gram-negative rods, Enterococcus species and yeast than the other sites. If central venous catheters need to be in place for extended periods of time, placement at a site with lower bacterial densities on the skin may help minimize catheter-associated infections. This study supports the subclavian as the preferred site.

Absence of significant effects by levamisole on circulating neutrophil levels in normal mice treated with 5-FU

When B6C3F1 mice were given a single intravenous (i.v.) injection of 150 mg/kg 5-fluorouracil (5-FU) their levels of circulating neutrophils plummeted, reaching a nadir at 6 to 7 days postdosing and then gradually increasing to normal and above-normal levels. Neutropenia (actual neutrophil count (ANC) below 100 ANC/microliters) extended until 8.7 +/- 0.2 days after 5-FU injection. When these mice were also given levamisole (2.5 mg/kg, po) on days 0-2 the mean time to ANC recovery greater than 100/microliters was 7.7 +/- 0.3 days, (p < 0.05 vs. controls), while IL-1 (2 micrograms/day, ip) positive controls yielded a mean time to > 100 ANC of 6.5 +/- 0.2 days. Although levamisole-treated mice attained normal neutrophil levels one day faster than controls did and this more rapid recovery led to their neutrophil levels being between 2- and 3-fold greater, these differences were not statistically significant. Effects were only manifested on neutrophil recoveries. There were no differences between levamisole-treated mice and controls when recovery rates for platelets, monocytes or lymphocytes were examined. These results demonstrate that levamisole has, at best, only weak myelopoietic properties against 5-FU-induced myelotoxicity in mice.

Source of Pseudomonas cepacia: ribotyping of isolates from patients and from the environment

Ribotyping, an analysis of bacterial strain identity based on chromosomal restriction fragment length polymorphisms, was performed on 68 isolates of Pseudomonas cepacia recovered from patients receiving care at the two children's hospitals in Philadelphia and from environmental samples. Twenty different ribotypes were identified. Ribotype R3 predominated among isolates from all three sources. These findings are consistent with the acquisition of P. cepacia from the environment or by person-to-person transmission.

2-Deoxy-D-glucose antinociception and serotonin receptor subtype antagonists: test-specific effects in rats

The antinociceptive actions of 2-deoxy-D-glucose (2-DG) are mediated in part by endogenous opioid, dopaminergic, cholinergic, histaminergic, and neurohormonal influences. Although 2-DG antinociception was not affected by tryptophan hydroxylase inhibition, a possible serotonergic role in 2-DG antinociception was investigated because of the existence of serotonin [5-hydroxytryptamine (5-HT)] receptor subtypes. The present study examined the effects of general (methysergide: 5 and 10 mg/kg), 5-HT2 (ritanserin: 2.5 mg/kg), and 5-HT3 (ICS-205,930: 0.25-5 mg/kg) receptor subtype antagonists upon 2-DG antinociception on the tail-flick and jump tests in rats. On the tail-flick test, 2-DG (450 mg/kg) antinociception was significantly reduced by all ICS-205,930 doses (48-58%) but unaffected by either methysergide (22-29% reduction) or ritanserin (6% reduction). In contrast, 2-DG antinociception on the jump test was significantly potentiated across the 120-min time course and across the 2-DG dose-response curve (100-650 mg/kg) by methysergide, ritanserin, and ICS-205,930 pretreatment. Each of the three antagonists produced significant leftward shifts in the peak and total 2-DG dose-response curve for the jump test. These data suggest different sites of action for 2-DG antinociception as a function of the pain test employed and a differential modulation by serotonin receptor subtypes at those sites.

Levamisole causes differential cytokine expression by elicited mouse peritoneal macrophages

Thioglycolate-elicited peritoneal macrophages from normal C57B1/6J mice were examined in vitro for bacterial lipopolysaccharide (LPS)-stimulated interleukin-1 (IL-1), IL-6, and tumor necrosis factor (TNF) production. Macrophages from mice administered a single oral dose of levamisole (3 mg/kg) 1 to 4 days prior to macrophage harvest demonstrated a twofold enhancement of IL-1 production compared to vehicle-treated mice. In contrast, IL-6 production and TNF production by the same macrophages were inhibited up to 36 and 62%, respectively, compared to production by macrophages harvested from vehicle-treated mice. Similar results were observed when IL-1 production and TNF production were followed in peritoneal exidate cells directly stimulated with levamisole in vitro. The ex vivo LPS-stimulated IL-1 production was enhanced 4 days after macrophage elicitation, whereas TNF and IL-6 production returned to baseline by 72 h after macrophage recruitment and augmentation. No evidence could be found for the presence of inhibitors of TNF or IL-6. The specificity of the IL-1, IL-6, and TNF bioactivities was demonstrated by neutralization with specific antisera. Immunoprecipitation studies of supernatants from biosynthetically labeled macrophages also revealed augmented IL-1 production and decreased IL-6 and TNF, indicating that levamisole may have affected cytokine production at the translational level. Kinetics studies revealed that ex vivo release of IL-6 and TNF by macrophages from levamisole-dosed mice was delayed compared to production of these cytokines by macrophages harvested from mice given vehicle only. The results may explain, in part, the reported ability of levamisole to ameliorate cases of rheumatoid arthritis or other autoimmune and inflammatory diseases by affecting the relative levels of cytokines produced by macrophages recruited to sites of injury, which are associated with inflammation and acute-phase protein synthesis.

Ribotype stability of serial pulmonary isolates of Pseudomonas cepacia

Eighty-three isolates of Pseudomonas capacia were recovered from respiratory secretions from 12 chronically colonized cystic fibrosis patients and examined by ribotype analysis. In 9 patients, the ribotype of the cultured P. cepacia remained unchanged throughout the entire period of observation, indicating chronic pulmonary colonization with a single strain. In each of the remaining 3 patients, two genetically distinct strains were detected among serial P. cepacia isolates. No significant change in clinical condition was correlated with the change in identity of the colonizing strain. In control experiments, the stability of strain ribotype was demonstrated among isolated that had been subcultured 100 times in vitro and among isolates recovered from chronically colonized mice. These data demonstrate the utility of ribotype analysis and indicate that most chronically colonized cystic fibrosis patients harbor a single strain of P. cepacia for prolonged periods.

Impact of treatment guidelines on use of ribavirin

During the 1987 through 1988 seasonal peak of respiratory syncytial virus (RSV), 177 courses of ribavirin were administered at St Christopher's Hospital for Children, a tertiary care medical center in Philadelphia, Pa. Charts were reviewed on 100 treated patients with proved or suspected RSV disease to determine adherence to American Academy of Pediatrics treatment guidelines. Ninety-four percent fulfilled criteria for the risk of significant morbidity: cardiac, pulmonary, or immunodeficiency conditions (38%); an age of 6 weeks or younger (35%); or severe illness (21%). Severe illness was defined as hypoxemia, hypercapnia, or marked tachypnea. Of those treated because of underlying conditions, 71% had RSV documented, as did 71% of patients aged 6 weeks or younger and 81% of patients with severe disease. A study of 80 consecutive patients who were hospitalized with illness compatible with RSV infection revealed that 56% of patients were treated with ribavirin. Adherence to guidelines led to ribavirin use in half of the hospitalized patients with suspected RSV infection. The majority of these patients received therapy because of underlying conditions or very young age.