Cross-Sectional Study of Soil-Transmitted Helminthiases in Black Belt Region of Alabama, USA

We conducted a cross-sectional study to determine the prevalence of soil-transmitted helminthiases (STH) in areas of rural Alabama, USA, that have sanitation deficits. We enrolled 777 children; 704 submitted stool specimens and 227 a dried blood spot sample. We microscopically examined stool specimens from all 704 children by using Mini-FLOTAC for helminth eggs. We tested a subset by using molecular techniques: real-time PCR analysis for 5 STH species, TaqMan Array Cards for enteric helminths, and digital PCR for Necator americanus hookworm. We analyzed dried blood spots for Strongyloides stercoralis and Toxocara spp. roundworms by using serologic testing. Despite 12% of our cohort reporting living in homes that directly discharge untreated domestic wastewater, stool testing for STH was negative; however, 5% of dried blood spots were positive for Toxocara spp. roundworms. Survey data suggests substantial numbers of children in this region may be exposed to raw sewage, which is itself a major public health concern.

A Pilot Comparison of Fixatives for Hookworm Real-time Polymerase Chain Reaction

Polymerase chain reaction (PCR) is increasingly used in the diagnosis of soil-transmitted helminth infections. Despite this, few studies have evaluated the impact of different fecal fixatives on the outcome of fecal helminth qPCR analysis, and none have evaluated the effect of commercial parasitology fixatives commonly used in diagnostic laboratories. We fixed dog feces containing Ancylostoma spp. hookworm eggs in zinc polyvinyl alcohol (Zn-PVA) and Total-Fix, and with 70% ethanol (EtOH) as a control. DNA was extracted at timepoints 11, 33, 64, and 94 days and subjected to Ancylostoma spp. quantitative PCR (qPCR). A linear regression model was created to assess the effect of preservative types on the temporal change of qPCR quantification cycle number (Cq) values, accounting for variances among individual animals. Fixation in 70% EtOH least affected Cq values over 94 days. Total-Fix preservation yielded a higher Cq overall, but there was no significant difference compared with 70% EtOH fixation. Fixation in Zn-PVA resulted in significantly (P < 0.001) higher Cq values than 70% EtOH after only 33 days and loss of amplification at 64 days. Consistent with other helminth fixation studies, 70% EtOH performed well in preserving hookworm DNA over 94 days. Total-Fix provided a comparable alternative for qPCR analysis for hookworm. Fixation in Zn-PVA resulted in loss of detectable hookworm DNA at 64 days, as determined by qPCR.

The relative importance of COVID-19 pandemic impacts on biodiversity conservation globally

The COVID-19 pandemic has had an enormous impact on almost all aspects of human society and endeavor; the natural world and its conservation have not been spared. Through a process of expert consultation, we identified and categorized, into 19 themes and 70 subthemes, the ways in which biodiversity and its conservation have been or could be affected by the pandemic globally. Nearly 60% of the effects have been broadly negative. Subsequently, we created a compendium of all themes and subthemes, each with explanatory text, and in August 2020 a diverse group of experienced conservationists with expertise from across sectors and geographies assessed each subtheme for its likely impact on biodiversity conservation globally. The 9 subthemes ranked highest all have a negative impact. These were, in rank order, governments sidelining the environment during their economic recovery, reduced wildlife-based tourism income, increased habitat destruction, reduced government funding, increased plastic and other solid waste pollution, weakening of nature-friendly regulations and their enforcement, increased illegal harvest of wild animals, reduced philanthropy, and threats to survival of conservation organizations. In combination, these impacts present a worrying future of increased threats to biodiversity conservation but reduced capacity to counter them. The highest ranking positive impact, at 10, was the beneficial impact of wildlife-trade restrictions. More optimistically, among impacts ranked 11-20, 6 were positive and 4 were negative. We hope our assessment will draw attention to the impacts of the pandemic and, thus, improve the conservation community's ability to respond to such threats in the future.

Rethinking the foam cosmesis for people with lower limb absence

BACKGROUND AND AIM

A recent survey of people with lower limb absence revealed that patients' satisfaction with their foam cosmesis is lower than desired. The aim of this project was to improve the lifelike appearance, functionality and durability of the cosmesis through a user-centred design methodology.

TECHNIQUE

Concept development and prototyping led to a new cosmesis design which features a cut-out located at the knee, inserted with an artificial patella made of a more rigid foam. It also features a full-length zip which provides easy access for maintenance. The new cosmesis was then mechanically tested for over 1 million cycles and clinically tested by six transfemoral prosthesis users over 18 patient months.

DISCUSSION

The new design is significantly more durable than the current standard model and has an enhanced lifelike appearance. It has potential to improve users' body image and reduce costs for healthcare providers. Clinical relevance This study contributes to practice by offering a new cosmesis design with enhanced appearance and durability, with the potential to improve patients' body image and reduce costs associated with cosmesis fitting and maintenance.

Firework-related injury in the Top End: a 16-year review

BACKGROUND

On July 1st on 'Territory Day', the public in the Northern Territory are permitted to purchase and operate consumer fireworks without a licence. Serious permanent injuries from fireworks are well described, leading to their banning in many other jurisdictions. This study describes those seriously injured by fireworks in the Top End of the Northern Territory, with the aim of identifying opportunities for prevention and harm minimization.

METHODS

This is a retrospective audit of all admitted patients with an injury from fireworks at the Royal Darwin Hospital between 2000 and 2015. The variables collected included demographic data and the circumstances around injury (operator versus bystander, alcohol involvement and day of device operation). The consequences such as injuries, operating theatre visits, length of stay and outpatient visits are described.

RESULTS

Fifty-five patients (including 17 children) suffered 67 injuries over the study period, resulting in 68 operating theatre visits, 322 hospital days and 380 outpatient appointments. Burns, hand and eye injuries predominate. Females (P = 0.000) and children (P = 0.029) were more likely to be injured as bystanders. Injuries on a day other than Territory Day were more likely to have alcohol involvement (P = 0.01), and occur in the operator (P = 0.017).

CONCLUSION

Consumer firework usage results in a small number of life altering injuries annually. Previous prevention campaigns focusing on device user safety should be expanded to include the safety of bystanders and children and reduce firework usage outside of the Territory Day.

Effect of interlamellar interactions on shear induced multilamellar vesicle formation

Shear-induced multilamellar vesicle (MLV) formation has been studied by coupling the small-angle neutron scattering (SANS) technique with neutron spin echo (NSE) spectroscopy. A 10% mass fraction of the nonionic surfactant pentaethylene glycol dodecyl ether (C₁₂E₅) in water was selected as a model system for studying weak inter-lamellar interactions. These interactions are controlled either by adding an anionic surfactant, sodium dodecyl sulfate, or an antagonistic salt, rubidium tetraphenylborate. Increasing the charge density in the bilayer induces an enhanced ordering of the lamellar structure. The charge density dependence of the membrane bending modulus was determined by NSE and showed an increasing trend with charge. This behavior is well explained by a classical theoretical model. By considering the Caillé parameters calculated from the SANS data, the layer compressibility modulus B¯ is estimated and the nature of the dominant inter-lamellar interaction is determined. Shear flow induces MLV formation around a shear rate of 10 s^-1, when a small amount of charge is included in the membrane. The flow-induced layer undulations are in-phase between neighboring layers when the inter-lamellar interaction is sufficiently strong. Under these conditions, MLV formation can occur without significantly changing the inter-lamellar spacing. On the other hand, in the case of weak inter-lamellar interactions, the flow-induced undulations are not in-phase, and greater steric repulsion leads to an increase in the inter-lamellar spacing with shear rate. In this case, MLV formation occurs as the amplitude of the undulations gets larger and the steric interaction leads to in-phase undulations between neighboring membranes.

Macracanthorhynchus ingens Infection in an 18-Month-Old Child in Florida: A Case Report and Review of Acanthocephaliasis in Humans

A case of acanthocephaliasis in an 18-month-old child caused by Macracanthorhynchus ingens is reported from Florida. This represents only the third documented case of this species in a human host. An overview of human cases of acanthocephaliasis in the literature is presented, along with a review of the biology, clinical manifestations and pathology in the human host, morphology, and diagnosis.

Salmonella Infections in The Gambia, 2005-2015

BACKGROUND

There are large data gaps in the epidemiology of diseases caused by Salmonella enterica in West Africa. Regional surveillance of Salmonella infections is necessary, especially with the emergence and spread of multidrug-resistant clones.

METHODS

Data on Salmonella isolated from various clinical specimens from patients from across The Gambia were collected and analyzed retrospectively from 2005 to April 2015. Antibiotic sensitivity testing of Salmonella isolates was performed by disk diffusion method. Serotyping and serogrouping of Salmonella isolates was performed using standard microbiology techniques.

RESULTS

Two hundred three Salmonella isolates were isolated from 190 patients: 52% (106/203) from blood and 39% (79/203) from stool specimens. Salmonella was also isolated from urine, aspirates, cerebrospinal fluid, wounds, and abscesses. The prevalence of Salmonella in blood cultures was 0.8% (106/13,905). Of the serotyped salmonellae, 14% (21/152) were Salmonella enterica serovar Typhi, whereas 86% (131/152) were serovars other than Typhi (nontyphoidal Salmonella). Of the 102 typed NTS isolates, 40% (41) were Salmonella enterica serovar Typhimurium, 10% (10) were Salmonella enterica serovar Enteritidis, and 3% (3) were Salmonella enterica serovar Arizonae. Overall, 70% (142/203) of the salmonellae were pansusceptible. Multidrug resistance was found in 4% (9/203) of the isolates, 3 of which were Salmonella Enteritidis.

CONCLUSIONS

Salmonellae are associated with a wide spectrum of invasive and noninvasive infections across all ages in The Gambia. There is evidence of multidrug resistance in salmonellae that warrants vigilant monitoring and surveillance.

The laboratory diagnosis of Strongyloides stercoralis

It is estimated that over 30million people worldwide are infected by the nematode, Strongyloides stercoralis1. It is endemic in sub-tropical and tropical parts of Australia, with high rates of infection documented in some indigenous communities2. Due to the potential for chronic autoinfection, that may persist for decades, migration leads to the presence of the infection in non-endemic areas1. Transmission to humans is generally through the penetration of larvae through the skin, following contact with faecally contaminated soil1. Disease severity ranges from asymptomatic chronic carriage to an overwhelming illness, where large numbers spread throughout the body, usually triggered by immunosuppression1.

A practical strategy for responding to a case of lymphatic filariasis post-elimination in Pacific Islands

Background

Lymphatic filariasis (LF) due to Wuchereria bancrofti is being eliminated from Oceania under the Pacific Elimination of Lymphatic Filariasis Programme. LF was endemic in Solomon Islands but in the 2010-2020 Strategic Plan of the Global Programme to Eliminate LF, Solomon Islands was listed as non-endemic for LF. In countries now declared free of LF an important question is what monitoring strategy should be used to detect any residual foci of LF?

This paper describes how a new case of elephantiasis in a post-elimination setting may be used as a trigger to initiate a local survey for LF.

Methods

The index case, a 44 year old male, presented to Atoifi Adventist Hospital, Malaita, Solomon Islands in April 2011 with elephantiasis of the lower leg. Persistent swelling had commenced 16 months previously. He was negative for antigen by TropBio Og4C3 ELISA and for microfilaria. A week later a survey of 197 people aged from 1 year to 68 years was conducted at Alasi, the index case’s village, by a research team from Atoifi Adventist Hospital and Atoifi College of Nursing. This represented 66.3% of the village population. Blood was collected between 22:00 and 03:00 by finger-prick and made into thick smears to detect microfilaria and collected onto filter paper for W. bancrofti antigen tests. A second group of 110 specimens was similarly collected from residents of the Hospital campus and inpatients. W. bancrofti antigen was tested for using the Trop-Bio Og4C3 test.

Results

One sample (1/307) from an 18 year old male from Alsai was positive for W. bancrofti antigen. No samples were positive for microfilaria. Although antigen-positivity indicated a live worm, the case was regarded as having been acquired some years previously.

Conclusions

We propose that when LF has been eliminated from a country, a case of elephantiasis should be a trigger to conduct a survey of the case’s community using a decision pathway. W. bancrofti antigen should be tested for with screening for microfilariae in antigen positive cases. The field survey was designed and conducted by local researchers, highlighting the value of local research capacity in remote areas.

Neuropsychiatric and socioeconomic status impact antiretroviral adherence and mortality in rural Zambia

We conducted a prospective cohort study of 496 adults starting antiretroviral treatment (ART) to determine the impact of neuropsychiatric symptoms and socioeconomic status on adherence and mortality. Almost 60% had good adherence based upon pharmacy records. Poor adherence was associated with being divorced, poorer, food insecure, and less educated. Longer travel time to clinic, concealing one's human immunodeficiency virus (HIV) status, and experiencing side effects predicted poor adherence. Over a third of the patients had cognitive impairment and poorer cognitive function was also associated with poor adherence. During follow-up (mean 275 days), 20% died-usually within 90 days of starting ART. Neuropsychiatric symptoms, advanced HIV, peripheral neuropathy symptoms, food insecurity, and poverty were associated with death. Neuropsychiatric symptoms, advanced HIV, and poverty remained significant independent predictors of death in a multivariate model adjusting for other significant factors. Social, economic, cognitive, and psychiatric problems impact adherence and survival for people receiving ART in rural Zambia.

Deployable laboratory response to influenza pandemic; PCR assay field trials and comparison with reference methods

BACKGROUND

The influenza A/H1N1/09 pandemic spread quickly during the Southern Hemisphere winter in 2009 and reached epidemic proportions within weeks of the official WHO alert. Vulnerable population groups included indigenous Australians and remote northern population centres visited by international travellers. At the height of the Australian epidemic a large number of troops converged on a training area in northern Australia for an international exercise, raising concerns about their potential exposure to the emerging influenza threat before, during and immediately after their arrival in the area. Influenza A/H1N1/09 became the dominant seasonal variant and returned to Australia during the Southern winter the following year.

METHODS

A duplex nucleic acid amplification assay was developed within weeks of the first WHO influenza pandemic alert, demonstrated in northwestern Australia shortly afterwards and deployed as part of the pathology support for a field hospital during a military exercise during the initial epidemic surge in June 2009.

RESULTS

The nucleic acid amplification assay was twice as sensitive as a point of care influenza immunoassay, as specific but a little less sensitive than the reference laboratory nucleic acid amplification assay. Repetition of the field assay with blinded clinical samples obtained during the 2010 winter influenza season demonstrated a 91.7% congruence with the reference laboratory method.

CONCLUSIONS

Rapid in-house development of a deployable epidemic influenza assay allowed a flexible laboratory response, effective targeting of limited disease control resources in an austere military environment, and provided the public health laboratory service with a set of verification tools for resource-limited settings. The assay method was suitable for rapid deployment in time for the 2010 Northern winter.

Transition from vesicles to small nanometer scaled vesicles, arising from the manipulation of curvature in dialkyl chain cationic/nonionic surfactant mixed aggregates by the addition of straight chain alkanols

The addition of straight chain alkanols to the dialkyl chain cationic/nonionic surfactant mixtures of dihexadecyl dimethyl ammonium bromide, DHDAB, and dodecaethylene monododecyl ether, C(12)E(12), has been used to manipulate the mean curvature of the self-assembled aggregates. This induces some significant structural changes and notably the formation of small unilamellar vesicles, nanometer scaled vesicles, L(sv). These structural changes have been measured and quantified using small angle neutron scattering, SANS. At a solution concentration of 25 mM, the DHDAB/C(12)E(12) mixtures have a structural evolution, from C(12)E(12) rich to DHDAB rich solution compositions, of small globular micelles, L(1), to micellar/vesicle coexistence, L(1)/L(v) or L(v)/L(1), to vesicle structures, L(v), bilamellar or multilamellar vesicles, blv or mlv. The impact of the addition of straight chain alkanols (in the range octanol to hexadecanol) depends upon the alkyl chain length and the amount of alcohol added. Furthermore, the effect of the addition of octanol and decanol appears to be distinctly different from that of the larger straight chain alkanols of dodecanol and hexadecanol. For the addition of octanol and decanol to C(12)E(12) rich DHDAB/C(12)E(12) mixtures, the alcohol is solubilized into the micellar core, and as the amount of alcohol added increases, significant micellar growth is ultimately observed. However, notably at intermediate DHDAB/C(12)E(12) solution compositions, in the region of L(1)/L(v) or L(v)/L(1) coexistance in the absence of alcohol, the addition of octanol or decanol promotes the formation of relatively small unilamellar vesicles, L(sv), nanometer sized vesicles, with a mean diameter in the range 70-140 A. For solutions that are rich in DHDAB, the addition of octanol or decanol results in a transition to L(v)/L(sv) coexistence and ultimately to L(v) formation. In contrast, the addition of the larger straight chain length alkanols, dodecanol or hexadecanol, to DHDAB/C(12)E(12) mixtures results in a somewhat different behavior. In this case, the addition of dodecanol or hexadecanol results in the transition from L(1) to L(1)/L(v) to L(v) occurring for solutions less rich in DHDAB than is observed in the absence of alcohol. That is, there is an enhanced tendency toward the formation of structures with a lower net curvature, either blv or mlv. Notably, for these mixtures, the small unilamellar nanometer scaled vesicle phase, L(sv), is absent.

Antiretroviral adherence in rural Zambia: the first year of treatment availability

We conducted a retrospective chart review of antiretroviral therapy (ART) clinic patients treated during the first 12 months after clinics opened in rural Zambia and assessed adherence based on clinic attendance, patient report, and staff assessment. We identified 255 eligible patients (mean age, 39.7 years; 44.3% male; 56.5% married; and 45.5% with only primary school education). Twenty percent had partners known to be HIV positive. Twenty percent were widowed. Thirty-seven percent had disclosed their HIV status to their spouse. Disclosure was less likely among women (27.5% versus 49.6%, P = 0.0005); 36.5% had "clinic buddies" to provide adherence support. Adherence rates were good for 59.2%. Disclosure of HIV status to ones' spouse (P = 0.047), knowing spouses' HIV status (P = 0.02), and having a clinic buddy (P = 0.01) were associated with good adherence. Social support is a key patient-level resource impacting ART adherence in rural Zambia. Limited spousal disclosure affects women more than men. Clinic buddies are associated with better adherence.

Poor clinical outcomes associated with a multi-drug resistant clonal strain of Pseudomonas aeruginosa in the Tasmanian cystic fibrosis population

BACKGROUND AND OBJECTIVE

Clonal strains of Pseudomonas aeruginosa have been identified in large cystic fibrosis (CF) centres. Whether such strains are more virulent or whether cross-infection between patients explains their widespread prevalence is unknown. This study described the epidemiology of P. aeruginosa infection in CF patients in Tasmania, Australia, an area with a high CF birth incidence. Patients in Tasmania are geographically dispersed and when this study was conducted (2003) there was no central CF clinic, with patients receiving treatment in regional hospitals.

METHODS

P. aeruginosa isolates from CF adults aged 15 years and over in Tasmania were genotyped using random amplified polymorphic DNA (RAPD)-PCR and clonal strains confirmed with pulsed field gel electrophoresis.

RESULTS

Airway samples were obtained from 41 patients (82% of the adult CF population). P. aeruginosa was isolated from 34 patients and nine (26%) of these individuals harboured P. aeruginosa strains with identical RAPD-PCR and pulsed field gel electrophoresis patterns (Australian Epidemic Strain III--AES III). AES III was isolated from patients in all regions of Tasmania and was distinct from the epidemic CF strains described on mainland Australia (AES I and II). The possible link between CF adults infected with AES III was attendance at family camps more than 12 years previously. Patients harbouring AES III had suffered significantly more exacerbations requiring hospitalisation during the 2 years prior to the study compared with patients infected with unique strains (P < 0.01). AES III displayed increased multi-antibiotic resistance compared with other strains (P < 0.001).

CONCLUSIONS

Clonal strains of P. aeruginosa may arise even in isolated CF populations. The increased exacerbation rate in patients infected with AES III and its antibiotic resistance profile strongly suggest increased virulence.

Efficacy of Piper (Piperaceae) extracts for control of common home and garden insect pests

Extracts from three species of the plant family Piperaceae, Piper nigrum [L.], Piper guineense [Schum & Thonn, and Piper tuberculatum [Jacq.], were tested for efficacy against insects from five orders. All three species contain isobutyl amides, plant secondary compounds that act as neurotoxins in insects. These materials are considered safe to mammals because Piper spp. were used for centuries for spice and medicinal purposes. When 24-h P. nigrum LC50 values were compared between common insect pests from eastern Canada and the northeastern United States, the most sensitive species in order of increasing lethal concentration were eastern tent caterpillar, Malacosoma americanum (F.) < European pine sawfly larvae, Neodiprion sertifer (Geoffroy) < spindle ermine moth larvae, Yponomeuta cagnagella [Hübner] < viburnum leaf beetle larvae, Pyrrhalta viburni [Paykull] < stripped cucumber beetle adults, Acalymma vittatum (F.) < Colorado potato beetle adults, Leptinotarsa decemlineata (Say) < Japanese beetle adults, Popillia japonica [Newman] < hairy chinch bug, Blissus leucopterus hirtis [Montandon]. The life stage tested was the point at which each species causes the greatest amount of damage to the host plant and the point at which most gardeners would likely choose to treat with a conventional synthetic insecticide. Greenhouse trials revealed that the pepper formulations also had a repellent activity, thus protecting plant leaves from 1) herbivory (lily leaf beetle, Lilioceris lilii [Scopoli], adults and larvae and stripped cucumber beetle adults) and 2) oviposition [European corn borer, Ostrinia nubilalis (Hübner)]. Combinations with other botanical extracts were additive at best in toxicity and repellent trials. Nontarget toxicity to beneficial invertebrates is a possibility because the P. nigrum LC50 for beneficial ladybird beetles was 0.2%. P. nigrum extracts can provide a reasonable level of control against lepidopteran and European pine sawfly larvae and also will work as a short-term repellent and feeding deterrent. It is recommended that the use of Piper extracts be restricted to small-scale spot treatments in residential areas where insect pest outbreaks have occurred.

Studies on [3H]CP-55940 binding in the human central nervous system: regional specific changes in density of cannabinoid-1 receptors associated with schizophrenia and cannabis use

A number of studies suggested that cannabis use can cause or exacerbate psychoses and may increase the risk of developing schizophrenia. These findings suggest that changes in the cannabinoid system of the brain may be involved in the pathology of schizophrenia. To determine whether changes in the cannabinoid system were present in the brains of subjects with schizophrenia, we used in situ radioligand binding and autoradiography to measure the binding of [3H]CP-55940 to the cannabinoid-1 receptor in the dorsolateral prefrontal cortex (Brodmann's area 9), caudate-putamen and areas of the temporal lobe from schizophrenic and control subjects, some of whom had ingested cannabis close to death. There was an increase in the density of [3H]CP-55940 binding to cannabinoid-1 receptors in the dorsolateral prefrontal cortex from subjects with schizophrenia (mean+/-S.E.M.: 142+/-9.9 vs 119+/-6.6fmol/mg estimated tissue equivalents; P<0.05) that was independent of recent cannabis ingestion. There was an increase in the density of cannabinoid-1 receptors in the caudate-putamen from subjects who had recently ingested cannabis (151+/-9.0 vs 123+/-7.2fmol/mg estimated tissue equivalents; P<0.05) that was independent of diagnoses. These data indicate that there are changes in cannabinoid-1 receptors in the dorsolateral prefrontal cortex that may prove to be associated with the pathology of schizophrenia. By contrast, changes in the density of cannabinoid-1 receptors may occur in the caudate-putamen in response to cannabis ingestion.

New chromogenic identification and detection of Staphylococcus aureus and methicillin-resistant S. aureus

This paper describes a new chromogenic plate medium, CHROMagar Staph aureus (CHROMagar, Paris, France), for the identification of Staphylococcus aureus on the basis of colony pigmentation. The abilities of CHROMagar Staph aureus, thermostable nuclease (DNase), and mannitol salt agar (MSA) to identify S. aureus isolates (n = 114) and discriminate between S. aureus and coagulase-negative staphylococci (CoNS; n = 22) were compared. CHROMagar Staph aureus proved to be more sensitive and specific than DNase and MSA, allowing a reliable, simple, and rapid method for the identification of S. aureus isolates. All CoNS encountered in this study with the exception of S. chromogenes could be easily differentiated from S. aureus on this medium. The supplementation with 4 microgram of oxacillin or methicillin per ml allowed simple identification of methicillin resistance in hospital-acquired S. aureus strains which show multiple-drug resistance profiles. Community-acquired methicillin-resistant S. aureus strains showing non-multi-drug resistance profiles require further evaluation on this new chromogenic medium. Methicillin or oxacillin resistance of all S. aureus isolates was confirmed by the detection of penicillin-binding protein 2a, encoded by the mecA gene, using the latex slide agglutination MRSA-Screen test (PBP 2' Test, DR900M; Oxoid).

Modification of gene expression by dietary antioxidants in radiation-induced apoptosis of mice splenocytes

The modification of radiation-induced apoptosis in splenocytes by a vitamin-containing dietary supplement was studied. For 45 days prior to irradiation at a lethal dose of 6 Gy, mice received a dietary supplement containing vitamins with antioxidant properties and microelements. The expression of TRPM-2 (a marker for programmed cell death), bcl-2 (the product of which has been shown to prevent apoptosis), superoxide dismutase, and catalase genes was studied at different time intervals after irradiation. Radiation-induced alterations in gene expression were different in the control and the antioxidant mixture-fed mice. The antioxidant mixture administration resulted in an inhibition of TRPM-2 expression both before and after irradiation. The bcl-2 mRNA content steadily increased after irradiation in splenocytes from antioxidant mixture-fed mice, while in the control group 2-h after irradiation only trace amount of bcl-2 mRNA was detected. In splenocytes from control mice, the expression of superoxide dismutase and catalase genes significantly decreased within 2-h after irradiation; whereas in mice receiving the antioxidant mixture, inhibition of catalase gene expression was not as prominent. The expression of superoxide dismutase gene was still high 24-h after irradiation. The antioxidant administration decreased the radiation-induced apoptosis and delayed internucleosomal fragmentation of DNA. Our data suggest that radiation-induced alteration of gene expression is, at least in part, determined by reactive oxygen species.

Expression of the human P2Y6 nucleotide receptor in normal placenta and gestational trophoblastic disease

The P2Y family of purinergic receptors are members of the G-protein-coupled receptor superfamily. The P2Y6 subtype is expressed at particularly high levels in the placenta, suggesting that P2Y6 plays an important role in placental function. However, the cellular localization of P2Y6 within the placenta is unknown. This study examined the expression of P2Y6 in first-trimester and full-term placental tissues, as well as examples of gestational trophoblastic disease, by Northern blot analysis and in situ hybridization. P2Y6 message was present at similar levels in first-trimester and full-term placenta, and in situ hybridization revealed that message was most abundant in the cytotrophoblast of the villi and chorionic plate at both gestational stages. The syncytiotrophoblast harbored lower levels of P2Y6 in first-trimester placenta, and by full-term, the syncytiotrophoblast only focally expressed P2Y6 transcripts. Neither the intermediate trophoblast nor nontrophoblastic elements of the placenta expressed P2Y6. Molar disease expressed P2Y6 in the villous trophoblast but not in the proliferative intermediate trophoblast, recapitulating the pattern of first-trimester placenta. Neither choriocarcinoma nor the choriocarcinoma cell lines JEG-3 and JAr expressed P2Y6 transcript. These findings reveal that P2Y6 mRNA production is highly characteristic of the epithelial-like cytotrophoblast and syncytiotrophoblast, whereas expression is absent in the mesenchymal-like intermediate trophoblast. Thus, P2Y6 may play an important role in trophoblastic development, differentiation, and neoplasia.

Prevalence and demographic determinants of metronidazole resistance by Helicobacter pylori in a large cosmopolitan cohort of Australian dyspeptic patients

BACKGROUND

The pre-treatment sensitivity of Helicobacter pylori to metronidazole is a key determinant of successful eradication therapy and should influence local choice of therapy. However, there are few data defining the prevalence of metronidazole resistance (MR) in Australia.

AIM

To determine prospectively the prevalence and demographic determinants of MR in H. pylori isolates from a large and cosmopolitan cohort of dyspeptic patients in Sydney.

METHODS

Consecutive dyspeptic patients undergoing endoscopy had gastric biopsies for histology, urease test and culture. Metronidazole resistance was determined by E-test after subculture. An MIC > 8 micrograms/mL defined MR. Patient age, gender, birthplace and history of previous nitroimidazole use were recorded.

RESULTS

In 732 patients, H. pylori was present in 46.4%. Culture was successful in 81% and subculture for MR in 88% of these. In 237 evaluable patients the overall MR rate was 59.1%. Five patients had had prior triple therapy for H. pylori (of which four of five had MR). Therefore, the primary MR rate in the study population was 58.6% (136/232). MR was more prevalent in younger patients (p = 0.0002). The MR rate was 70.4% in patients 18-39 years, 66.7% in those aged 40-59 years and lowest (38.9%) in those 60 years or older (p = 0.002). The MR rate was highest in patients born in Southeast Asia (72.8%, 59/81) and significantly higher than in Australian born (48.1%, 26/54), or Southern European (46.2%, 24/52) born patients (p = 0.002). There was no gender difference. Logistic regression to determine the impact of each variable (birthplace, age and gender) on MR identified Southeast Asia birthplace as a factor associated with greater likelihood of harbouring an MR isolate (OR 1.88, p = 0.02). Southern European born patients had the lowest risk of MR (OR 0.70, p = 0.02) as did patients older than 60 years (OR 0.56, p = 0.04). A definite history of prior metronidazole use was infrequent and not predictive of MR.

CONCLUSIONS

While a high rate of MR is not unexpected in patients born in developing countries, the high rate in Australian born patients is surprising and of concern. This may relate to the high local usage of nitroimidazoles as monotherapy and has important implications for the effectiveness of metronidazole containing triple therapies.

Clozapine and olanzapine treatment decreases rat cortical and limbic GABA(A) receptors

The density of GABA(A) receptors in the hippocampus and the temporal cortex from rats treated for 28 days with either haloperidol, chlorpromazine, clozapine or olanzapine was measured. Compared to haloperidol (0.01 and 0.1 mg kg(-1) day(-1)) and chlorpromazine (0.1 and 1 mg kg(-1) day(-1)), clozapine and olanzapine (0.1 and 1 mg kg(-1) day(-1)) markedly decreased the density of GABA(A) receptors in these two brain regions. These data suggest that modulation of GABAergic transmission could be an important action of some antipsychotic drugs.

Candidaemia in an Australian teaching hospital: relationship to central line and TPN use

We performed a retrospective review of patient case records to identify risk factors for candidaemia and to assess incidence, management and outcome of candidaemia in an Australian teaching hospital. Between January 1994 and June 1996, 38 cases of candidaemia were identified. The incidence was 0.74 per 1000 admissions of 24 h duration, and 1.54 per 1000 admissions of 5 days or more. The mortality rate was 34%, with eight of 13 (62%) of these deaths attributable to candidaemia. Risk factors included underlying gastrointestinal disease (66%) and recent abdominal surgery (61%), while recent broad spectrum antibiotic use was a contributing factor in 95%. Twenty-nine patients (76%) had a vascular access device in situ at time of detection. This was the apparent source of candidaemia in 28 (97%). Twenty-six (90%) were being used for TPN administration. Of patients receiving TPN, 5.2% developed candidaemia. Standard central venous catheters (CVC) were present in 21 patients (55%), having been in situ for an average of 12.7 days. Eighteen (86%) had been in situ for 7 days or more. Management involved removal of any implicated intravascular device. Thirty of 33 early survivors received antifungal chemotherapy. Therapy with amphotericin B, fluconazole alone or amphotericin B followed by fluconazole was equally effective. Concurrent corticosteroid use and neutropaenia contributed to increased mortality. Candidaemia is not benign. Policies regarding regular changing of central lines, especially in the setting of TPN administration and control of broad spectrum antibiotic use are appropriate measures aimed to reduce incidence. Management involves removal of implicated lines and antifungal chemotherapy. Pre-emptive therapy for candida infection should be considered in selected patients with the likelihood of TPN-related central line sepsis. Fluconazole is an effective alternative to amphotericin B in non-neutropenic patients.

Staphylococcal bacteraemia: the hospital or the home? A review of Staphylococcus aureus bacteraemia at Concord Hospital in 1993

AIMS

To examine the risk factors for, and the complications and mortality of, Staphylococcus aureus bacteraemia.

METHODS

A retrospective case review of patients with S. aureus bacteraemia in 1993 diagnosed at the Concord Repatriation General Hospital, Sydney.

RESULTS

Of 104 cases reviewed, 32 were due to methicillin resistant S. aureus (MRSA), 73 were due to methicillin sensitive S. aureus (MSSA) and one was a dual infection. Twenty-eight of the bacteraemias were community-acquired, including one case of MRSA, and 76 were hospital-acquired; 38% had an implanted prosthetic device or graft. The average age (68 years), incidence of underlying diseases and hospitalisation in the past month (26%) did not differ between MRSA and MSSA groups. MRSA was more likely in patients with recent broad-spectrum antibiotic use (53% vs 0, p < .01). Vascular access was the commonest source of sepsis (61%) but in community-acquired cases the source was unknown in 50%. Use of central line access was more predictive of MRSA infection (75% vs 49%, p = .018). In hospital-acquired infection, MRSA sepsis occurred later in the course of the admission (26 days vs eight days, p < .01). Directly attributable mortality was highest in MRSA and community-acquired MSSA infection (9% and 11%) compared with hospital-acquired MSSA infection (1%).

CONCLUSIONS

Nosocomial S. aureus bacteraemia, particularly MRSA, is a major source of preventable morbidity, which could be addressed by improved infection control of MRSA, antibiotic use and attention to central line catheter use.

A prospective study of Clostridium difficile infection and colonization in pediatric oncology patients

BACKGROUND

Patients with cancer often receive broad spectrum antibiotics in addition to antineoplastic chemotherapy. Both treatments predispose adult oncology patients to infection and colonization with Clostridium difficile, but the role of this pathogen in pediatric oncology patients is poorly defined.

METHODS

A prospective study of 149 fecal samples from symptomatic pediatric oncology patients and 58 samples from asymptomatic patients was performed. Each sample was analyzed for the presence of C. difficile and its toxins A and B.

RESULTS

In 8.7% of the symptomatic samples and 19% of the asymptomatic samples toxigenic C. difficile was found. No association was found between either the use of antibiotics and/or the administration of chemotherapy and the presence of toxigenic C. difficile. Younger children were more likely to be infected or colonized with C. difficile, and there was no evidence of nosocomial transmission of C. difficile within the study population.

CONCLUSIONS

As toxigenic C. difficile may form part of the normal flora in young children, this study indicates that in the absence of a defined outbreak, C. difficile does not appear to be an important pathogen in pediatric oncology patients.

Prevalence of Bartonella henselae bacteremia, the causative agent of cat scratch disease, in an Australian cat population

In order to determine the prevalence of Bartonella henselae becteremia in an Australian cat population we examined blood cultures on a group of Sydney cats. Cats referred to the Concord Animal Hospital for euthanasia were selected randomly for blood culture and serum sampling. Blood samples were lysed and centrifuged and then cultured for up to five weeks. Suspicious colonies were identified biochemically as probable B. henselae. Selected isolates were confirmed as B. henselae using the polymerase chain reaction. Of the cats accrued throughout Sydney, 27/77 (35%) were culture positive for B. henselae, of these 24/59 (40%) were feral cats and 3/18 (16%) were domestic. Most cats in the study were younger than one year (mean 9.9 months). Our study demonstrates that bacteremia with B. henselae is common in the metropolitan cat population and suggests that it is particularly prevalent among feral animals. By contrast Cat Scratch Disease (CSD) is a relatively uncommon clinical diagnosis in the Australian population. Explanations for this discrepancy may include poor transmission, low bacterial virulence and underdiagnosis. It is possible that feral animals are a greater potential risk source for this infection than domestic cats.

Evaluation of CHROMagar Orientation for differentiation and presumptive identification of gram-negative bacilli and Enterococcus species

A new chromogenic plate medium, CHROMagar Orientation, was evaluated for use in the differentiation and presumptive identification of gram-negative bacilli and Enterococcus species by a multipoint inoculation (replicator) technique. In this study, 1,404 gram-negative bacilli and 74 enterococcal isolates were tested on CHROMagar Orientation. Six control American Type Culture Collection strains were also included with the testing to ensure quality control of the media. Of the Escherichia coli isolates (n = 588) tested, 99.3% produced a pink-to-red color. Only in four isolates that were O-nitrophenyl-beta-D-galactopyranoside (ONPG) negative did this result differ. Proteus mirabilis and P. vulgaris were well differentiated on this medium. P. mirabilis (n = 184) produced a clear colony with diffusible brown pigment around the periphery. By contrast, 15 of 16 P. vulgaris isolates produced bluish-green colonies with a slight brown background. All Aeromonas hydrophila isolates (n = 26) tested produced clear to pink colonies at 35 to 37 degrees C. This colony color changed to blue after 2 to 3 h of incubation at room temperature. A. hydrophila exhibited stronger color and better growth at 30 degrees C. Serratia marcescens (n = 29) demonstrated an aqua blue color that deepened to a darker blue when exposed to room temperature. All enterococcal isolates (n = 74) resulted in a blue color and gave pinpoint colonies on purity subcultures at 35 to 37 degrees C after 18 h of incubation. Similarity in color resulted in failure to discriminate accurately between Klebsiella, Enterobacter, and Citrobacter species. However, these species could be readily differentiated from other members of the family Enterobacteriaceae. Pseudomonas aeruginosa (n = 151) was easily differentiated from members of the Enterobacteriaceae but was less easily distinguishable from other gram-negative nonmembers of the Enterobacteriaceae. The medium was found to facilitate easy visual detection of mixed bacterial isolates in culture. When used in a replicator system, it easily detected mixed growths of organisms which may have otherwise led to false antibiotic susceptibility results. These mixed growths were not obvious on the routine susceptibility testing medium (Isosensitest).