Molecular Epidemiology of Clostridioides difficile Infections in Children.

Clostridioides difficile is a prominent cause of health care-related gastrointestinal illness in adults. C. difficile infection (CDI) has been researched for over 40 years; however, research on pediatric CDI specifically has lagged behind for various reasons. Over the past decade, C. difficile has been increasingly reported as a cause of a broad spectrum of gastrointestinal diseases in children, ranging from mild self-limiting diarrhea to severe conditions such as pseudomembranous colitis and toxic megacolon. Recent publications have shown a rise in CDI incidence in children in different parts of the world, especially in patients with particular comorbidities such as hematological malignancies and inflammatory bowel disease. In addition, rising CDI rates have been reported in children in the community without traditional risk factors for CDI. Due to the extensive use of sensitive molecular detection methods to diagnose CDI in many countries, differentiating children who require treatment from those colonized with toxigenic strains remains a problem. Consequently, the molecular epidemiology of pediatric CDI is poorly understood. Even though well-known C. difficile strains causing CDI in children have been described (including hypervirulent strains such as ribotypes 027 and 078), there is a paucity of information about specific C. difficile strains. This mini-review summarizes the information that is currently available on the molecular epidemiology of CDI in children.

An environmental cleaning bundle and health-care-associated infections in hospitals (REACH): a multicentre, randomised trial.

BACKGROUND: The hospital environment is a reservoir for the transmission of microorganisms. The effect of improved cleaning on patient-centred outcomes remains unclear. We aimed to evaluate the effectiveness of an environmental cleaning bundle to reduce health care-associated infections in hospitals. METHODS: The REACH study was a pragmatic, multicentre, randomised trial done in 11 acute care hospitals in Australia. Eligible hospitals had an intensive care unit, were classified by the National Health Performance Authority as a major hospital (public hospitals) or having more than 200 inpatient beds (private hospitals), and had a health-care-associated infection surveillance programme. The stepped-wedge design meant intervention periods varied from 20 weeks to 50 weeks. We introduced the REACH cleaning bundle, a multimodal intervention, focusing on optimising product use, technique, staff training, auditing with feedback, and communication, for routine cleaning. The primary outcomes were incidences of health-care-associated Staphylococcus aureus bacteraemia, Clostridium difficile infection, and vancomycin-resistant enterococci infection. The secondary outcome was the thoroughness of cleaning of frequent touch points, assessed by a fluorescent marking gel. This study is registered with the Australian and New Zealand Clinical Trial Registry, number ACTRN12615000325505. FINDINGS: Between May 9, 2016, and July 30, 2017, we implemented the cleaning bundle in 11 hospitals. In the pre-intervention phase, there were 230 cases of vancomycin-resistant enterococci infection, 362 of S aureus bacteraemia, and 968 C difficile infections, for 3 534 439 occupied bed-days. During intervention, there were 50 cases of vancomycin-resistant enterococci infection, 109 of S aureus bacteraemia, and 278 C difficile infections, for 1 267 134 occupied bed-days. After the intervention, vancomycin-resistant enterococci infections reduced from 0·35 to 0·22 per 10 000 occupied bed-days (relative risk 0·63, 95% CI 0·41-0·97, p=0·0340). The incidences of S aureus bacteraemia (0·97 to 0·80 per 10 000 occupied bed-days; 0·82, 0·60-1·12, p=0·2180) and C difficile infections (2·34 to 2·52 per 10 000 occupied bed-days; 1·07, 0·88-1·30, p=0·4655) did not change significantly. The intervention increased the percentage of frequent touch points cleaned in bathrooms from 55% to 76% (odds ratio 2·07, 1·83-2·34, p<0·0001) and bedrooms from 64% to 86% (1·87, 1·68-2·09, p<0·0001). INTERPRETATION: The REACH cleaning bundle was successful at improving cleaning thoroughness and showed great promise in reducing vancomycin-resistant enterococci infections. Our work will inform hospital cleaning policy and practice, highlighting the value of investment in both routine and discharge cleaning practice. FUNDING: National Health and Medical Research Council (Australia).

The Epidemiology of Clostridium difficile Infection in Japan: A Systematic Review.

To increase understanding of the epidemiology, risks, consequences and resource utilization of Clostridium difficile infection (CDI) in Japan, a systematic literature review was undertaken of relevant publications from January 2006 to November 2017. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and methods, 55 articles met the criteria for full review. The majority (58%) of studies were from a single site, with the most recent data from 2015. The incidence, reported prevalence and recurrence rate of CDI in Japan were 0.8-4.71/10,000 patient-days, 0.3-5.5/1000 patients and 3.3-27.3%, respectively, and varied according to setting, population, CDI definition and detection method. Most C. difficile isolates associated with CDI in Japan were toxin A+B+, with a low level of C. difficile binary toxin-positive (CDT+) strains (0-6.8% reported across studies). The most common C. difficile PCR ribotypes associated with infection in Japan were smz/018, 002, 052 and 369. Data regarding the impact of CDI on length of hospital stay were limited. Reported all-cause mortality in patients with CDI ranged from 3.4 to 15.1% between 2007 and 2013. Two studies assessed risk factors for CDI recurrence, identifying malignant disease, intensive care unit hospitalization and use of proton pump inhibitors as factors increasing the risk of initial and/or recurrent CDI. No study analyzed initial CDI treatment in relation to recurrence. More comprehensive surveillance and coordinated studies are needed to map trends, understand risk factors, and recognize the extent and impact of CDI in Japanese patients. FUNDING: Astellas Pharma, Inc. Plain language summary available for this article.

Tea tree oil gel for mild to moderate acne; a 12 week uncontrolled, open-label phase II pilot study.

BACKGROUND: The efficacy, tolerability and acceptability of a tea tree oil gel (200 mg/g) and face wash (7 mg/g) were evaluated for the treatment of mild to moderate facial acne. METHODS: In this open-label, uncontrolled phase II pilot study, participants applied tea tree oil products to the face twice daily for 12 weeks and were assessed after 4, 8 and 12 weeks. Efficacy was determined from total numbers of facial acne lesions and the investigator global assessment (IGA) score. Tolerability was evaluated by the frequency of adverse events and the mean tolerability score determined at each visit. Product acceptability was assessed via a questionnaire at the end of the study period. RESULTS: Altogether 18 participants were enrolled, of whom 14 completed the study. Mean total lesion counts were 23.7 at baseline, 17.2 at 4, 15.1 at 8 and 10.7 at 12 weeks. Total lesion counts differed significantly over time by repeated measures anova (P < 0.0001). The mean IGA score was 2.4 at baseline, 2.2 at 4, 2.0 at 8 and 1.9 at 12 weeks, which also differed significantly over time (P = 0.0094). No serious adverse events occurred and minor local tolerability events were limited to peeling, dryness and scaling, all of which resolved without intervention. CONCLUSION: This study shows that the use of the tea tree oil products significantly improved mild to moderate acne and that the products were well tolerated.

Clostridium difficile Infections amongst Patients with Haematological Malignancies: A Data Linkage Study.

OBJECTIVES: Identify risk factors for Clostridium difficile infection (CDI) and assess CDI outcomes among Australian patients with a haematological malignancy. METHODS: A retrospective cohort study involving all patients admitted to hospitals in Western Australia with a haematological malignancy from July 2011 to June 2012. Hospital admission data were linked with all hospital investigated CDI case data. Potential risk factors were assessed by logistic regression. The risk of death within 60 and 90 days of CDI was assessed by Cox Proportional Hazards regression. RESULTS: There were 2085 patients of whom 65 had at least one CDI. Twenty percent of CDI cases were either community-acquired, indeterminate source or had only single-day admissions in the 28 days prior to CDI. Using logistic regression, having acute lymphocytic leukaemia, neutropenia and having had bacterial pneumonia or another bacterial infection were associated with CDI. CDI was associated with an increased risk of death within 60 and 90 days post CDI, but only two deaths had CDI recorded as an antecedent factor. Ribotyping information was available for 33 of the 65 CDIs. There were 19 different ribotypes identified. CONCLUSIONS: Neutropenia was strongly associated with CDI. While having CDI is a risk factor for death, in many cases it may not be a direct contributor to death but may reflect patients having higher morbidity. A wide variety of C. difficile ribotypes were found and community-acquired infection may be under-estimated in these patients.

Comorbidities, Exposure to Medications, and the Risk of Community-Acquired Clostridium difficile Infection: a systematic review and meta-analysis.

BACKGROUND: Clostridium difficile infection (CDI) has been extensively described in healthcare settings; however, risk factors associated with community-acquired (CA) CDI remain uncertain. This study aimed to synthesize the current evidence for an association between commonly prescribed medications and comorbidities with CA-CDI. METHODS: A systematic search was conducted in 5 electronic databases for epidemiologic studies that examined the association between the presence of comorbidities and exposure to medications with the risk of CA-CDI. Pooled odds ratios were estimated using 3 meta-analytic methods. Subgroup analyses by location of studies and by life stages were conducted. RESULTS: Twelve publications (n=56,776 patients) met inclusion criteria. Antimicrobial (odds ratio, 6.18; 95% CI, 3.80-10.04) and corticosteroid (1.81; 1.15-2.84) exposure were associated with increased risk of CA-CDI. Among the comorbidities, inflammatory bowel disease (odds ratio, 3.72; 95% CI, 1.52-9.12), renal failure (2.64; 1.23-5.68), hematologic cancer (1.75; 1.02-5.68), and diabetes mellitus (1.15; 1.05-1.27) were associated with CA-CDI. By location, antimicrobial exposure was associated with a higher risk of CA-CDI in the United States, whereas proton-pump inhibitor exposure was associated with a higher risk in Europe. By life stages, the risk of CA-CDI associated with antimicrobial exposure greatly increased in adults older than 65 years. CONCLUSIONS: Antimicrobial exposure was the strongest risk factor associated with CA-CDI. Further studies are required to investigate the risk of CA-CDI associated with medications commonly prescribed in the community. Patients with diarrhea who have inflammatory bowel disease, renal failure, hematologic cancer, or diabetes are appropriate populations for interventional studies of screening.

Clostridium difficile exposure as an insidious source of infection in healthcare settings: an epidemiological model.

BACKGROUND: Clostridium difficile is the leading cause of infectious diarrhea in hospitalized patients. Its epidemiology has shifted in recent years from almost exclusively infecting elderly patients in whom the gut microbiota has been disturbed by antimicrobials, to now also infecting individuals of all age groups with no recent antimicrobial use. METHODS: A stochastic mathematical model was constructed to simulate the modern epidemiology of C. difficile in a healthcare setting, and, to compare the efficacies of interventions. RESULTS: Both the rate of colonization and the incidence of symptomatic disease in hospital inpatients were insensitive to antimicrobial stewardship and to the prescription of probiotics to expedite healthy gut microbiota recovery, suggesting these to be ineffective interventions to limit transmission. Comparatively, improving hygiene and sanitation and reducing average length of stay more effectively reduced infection rates. Although the majority of new colonization events are a result of within-hospital ward exposure, simulations demonstrate the importance of imported cases with new admissions. CONCLUSIONS: By analyzing a wide range of screening sensitivities, we identify a previously ignored source of pathogen importation: although capturing all asymptomatic as well as symptomatic introductions, individuals who are exposed but not yet colonized will be missed by even a perfectly sensitive screen on admission. Empirical studies to measure the duration of this latent period of infection will be critical to assessing C. difficile control strategies. Moreover, identifying the extent to which the exposed category of individual contributes to pathogen importation should be explicitly considered for all infections relevant to healthcare settings.

Effect of habituation to tea tree (Melaleuca alternifolia) oil on the subsequent susceptibility of Staphylococcus spp. to antimicrobials, triclosan, tea tree oil, terpinen-4-ol and carvacrol.

The aim of this study was to seek additional data on the antimicrobial susceptibility of Staphylococcus spp. after habituation to low levels of the topical antimicrobial agent tea tree (Melaleuca alternifolia) oil. Meticillin-susceptible Staphylococcus aureus (MSSA), meticillin-resistant S. aureus (MRSA) and coagulase-negative staphylococci (CoNS) were habituated to 0.075% tea tree oil for 3 days. Subsequently, the susceptibility of five isolates each of MSSA, MRSA and CoNS to fusidic acid, mupirocin, chloramphenicol, linezolid and vancomycin was determined by Etest, and susceptibility to tea tree oil, terpinen-4-ol, carvacrol and triclosan was determined by agar dilution. Following habituation to 0.075% tea tree oil, antimicrobial MICs differed between control and habituated isolates on 33 occasions (out of a possible 150), with MICs being higher in habituated isolates on 22 occasions. Using clinical breakpoint criteria, one MSSA isolate changed susceptibility category from vancomycin-susceptible (MIC=2 µg/mL) to intermediate susceptibility (MIC=3 µg/mL) after habituation in one of two replicates. For the non-antibiotic antimicrobial agents, MICs of habituated and control isolates differed on 12 occasions (out of a possible 120); 10 occasions in MRSA and 2 occasions in MSSA. MICs were higher for habituated isolates on five occasions. However, all the differences were one serial dilution only and were not regarded as significant. Habituation to sublethal concentrations of tea tree oil led to minor changes in MICs of antimicrobial agents, only one of which may have been clinically relevant. There is no evidence to suggest that tea tree oil induces resistance to antimicrobial agents.

Tea tree oil (5%) body wash versus standard care (Johnson's Baby Softwash) to prevent colonization with methicillin-resistant Staphylococcus aureus in critically ill adults: a randomized controlled trial.

OBJECTIVES: To determine whether the daily use of 5% tea tree oil (TTO) body wash (Novabac 5% Skin Wash) compared with standard care [Johnson's Baby Softwash (JBS)] had a lower incidence of methicillin-resistant Staphylococcus aureus (MRSA) colonization. PATIENTS: The study setting was two intensive care units (ICUs; mixed medical, surgical and trauma) in Northern Ireland between October 2007 and July 2009. The study population comprised 391 patients who were randomized to JBS or TTO body wash. METHODS: This was a Phase 2/3, prospective, open-label, randomized, controlled trial. TRIAL REGISTRATION: ISRCTN65190967. The primary outcome was new MRSA colonization during ICU stay. Secondary outcomes included the incidence of MRSA bacteraemia and maximum increase in sequential organ failure assessment score. RESULTS: A total of 445 patients were randomized to the study. After randomization, 54 patients were withdrawn; 30 because of a positive MRSA screen at study entry, 11 due to lack of consent, 11 were inappropriately randomized and 2 had adverse reactions. Thirty-nine (10%) patients developed new MRSA colonization (JBS n = 22, 11.2%; TTO body wash n = 17, 8.7%). The difference in percentage colonized (2.5%, 95% CI - 8.95 to 3.94; P = 0.50) was not significant. The mean maximum increase in sequential organ failure assessment score was not significant (JBS 1.44, SD 1.92; TTO body wash 1.28, SD 1.79; P = 0.85) and no study patients developed MRSA bacteraemia. CONCLUSIONS: Compared with JBS, TTO body wash cannot be recommended as an effective means of reducing MRSA colonization.

Association between early bacterial carriage and otitis media in Aboriginal and non-Aboriginal children in a semi-arid area of Western Australia: a cohort study.

BACKGROUND: Streptococcus pneumoniae (Pnc), nontypeable Haemophilus influenzae (NTHi) and Moraxella catarrhalis (Mcat) are the most important bacterial pathogens associated with otitis media (OM). Previous studies have suggested that early upper respiratory tract (URT) bacterial carriage may increase risk of subsequent OM. We investigated associations between early onset of URT bacterial carriage and subsequent diagnosis of OM in Aboriginal and non-Aboriginal children living in the Kalgoorlie-Boulder region located in a semi-arid zone of Western Australia. METHODS: Aboriginal and non-Aboriginal children who had nasopharyngeal aspirates collected at age 1- < 3 months and at least one clinical examination for OM by an ear, nose and throat specialist before age 2 years were included in this analysis. Tympanometry to detect middle ear effusion was also performed at 2- to 6-monthly scheduled field visits from age 3 months. Multivariate regression models were used to investigate the relationship between early carriage and subsequent diagnosis of OM controlling for environmental factors. RESULTS: Carriage rates of Pnc, NTHi and Mcat at age 1- < 3 months were 45%, 29% and 48%, respectively, in 66 Aboriginal children and 14%, 5% and 18% in 146 non-Aboriginal children. OM was diagnosed at least once in 71% of Aboriginal children and 43% of non-Aboriginal children. After controlling for age, sex, presence of other bacteria and environmental factors, early nasopharyngeal carriage of NTHi increased the risk of subsequent OM (odds ratio = 3.70, 95% CI 1.22-11.23) in Aboriginal children, while Mcat increased the risk of OM in non-Aboriginal children (odds ratio = 2.63, 95% CI 1.32-5.23). Early carriage of Pnc was not associated with increased risk of OM. CONCLUSION: Early NTHi carriage in Aboriginal children and Mcat in non-Aboriginal children is associated with increased risk of OM independent of environmental factors. In addition to addressing environmental risk factors for carriage such as overcrowding and exposure to environmental tobacco smoke, early administration of pneumococcal-Haemophilus influenzae D protein conjugate vaccine to reduce bacterial carriage in infants, may be beneficial for Aboriginal children; such an approach is currently being evaluated in Australia.

Topically applied Melaleuca alternifolia (tea tree) oil causes direct anti-cancer cytotoxicity in subcutaneous tumour bearing mice.

BACKGROUND: Melaleuca alternifolia (tea tree) oil (TTO) applied topically in a dilute (10%) dimethyl sulphoxide (DMSO) formulation exerts a rapid anti-cancer effect after a short treatment protocol. Tumour clearance is associated with skin irritation mediated by neutrophils which quickly and completely resolves upon treatment cessation. OBJECTIVE: To examine the mechanism of action underlying the anti-cancer activity of TTO. METHODS: Immune cell changes in subcutaneous tumour bearing mice in response to topically applied TTO treatments were assessed by flow cytometry and immunohistochemistry. Direct cytotoxicity of TTO on tumour cells in vivo was assessed by transmission electron microscopy. RESULTS: Neutrophils accumulate in the skin following topical 10% TTO/DMSO treatment but are not required for tumour clearance as neutrophil depletion did not abrogate the anti-cancer effect. Topically applied 10% TTO/DMSO, but not neat TTO, induces an accumulation and activation of dendritic cells and an accumulation of T cells. Although topical application of 10% TTO/DMSO appears to activate an immune response, anti-tumour efficacy is mediated by a direct effect on tumour cells in vivo. The direct cytotoxicity of TTO in vivo appears to be associated with TTO penetration. CONCLUSION: Future studies should focus on enhancing the direct cytotoxicity of TTO by increasing penetration through skin to achieve a higher in situ terpene concentration. This coupled with boosting a more specific anti-tumour immune response will likely result in long term clearance of tumours.

Candida albicans adhesion to human epithelial cells and polystyrene and formation of biofilm is reduced by sub-inhibitory Melaleuca alternifolia (tea tree) essential oil.

This study investigated the effects of the volatile terpene-rich oil from Melaleuca alternifolia (tea tree oil) on the formation of biofilms and the adhesion of C. albicans cells to both biotic and abiotic surfaces. Biofilm formation on polystyrene was significantly inhibited for 70% of the isolates at the lowest test concentration of 0.016% of tea tree oil (TTO) when quantified by XTT and 40% of isolates when measured by crystal violet staining. Adhesion to polystyrene, quantified by crystal violet staining, was significantly reduced for 3 isolates at 0.031%, 6 isolates at 0.062% and 0.125% and for all 7 isolates at 0.25% TTO. Reductions in adhesion were not due to loss of viability (at concentrations of ≤ 0.125%) or interactions between the TTO and polystyrene. Similarly, adhesion to buccal epithelial and HeLa cells was also significantly reduced in the presence of 0.016-0.062% TTO. Treatment with 0.125% TTO, but not 0.062%, decreased the cell surface hydrophobicity of C. albicans, indicating one potential mechanism by which adhesion may be reduced. These data demonstrate that sub-inhibitory TTO reduces the adhesion of C. albicans to both human cells and polystyrene, inhibits biofilm formation and decreases cell surface hydrophobicity.

Effects of Melaleuca alternifolia (tea tree) essential oil and the major monoterpene component terpinen-4-ol on the development of single- and multistep antibiotic resistance and antimicrobial susceptibility.

This study examined the effect of subinhibitory Melaleuca alternifolia (tea tree) essential oil on the development of antibiotic resistance in Staphylococcus aureus and Escherichia coli. Frequencies of single-step antibiotic-resistant mutants were determined by inoculating bacteria cultured with or without subinhibitory tea tree oil onto agar containing 2 to 8 times the MIC of each antibiotic and with or without tea tree oil. Whereas most differences in resistance frequencies were relatively minor, the combination of kanamycin and tea tree oil yielded approximately 10-fold fewer resistant E. coli mutants than kanamycin alone. The development of multistep antibiotic resistance in the presence of tea tree oil or terpinen-4-ol was examined by culturing S. aureus and E. coli isolates daily with antibiotic alone, antibiotic with tea tree oil, and antibiotic with terpinen-4-ol for 6 days. Median MICs for each antibiotic alone increased 4- to 16-fold by day 6. Subinhibitory tea tree oil or terpinen-4-ol did not greatly alter results, with day 6 median MICs being either the same as or one concentration different from those for antibiotic alone. For tea tree oil and terpinen-4-ol alone, day 6 median MICs had increased 4-fold for S. aureus (n = 18) and 2-fold for E. coli (n = 18) from baseline values. Lastly, few significant changes in antimicrobial susceptibility were seen for S. aureus and S. epidermidis isolates that had been serially subcultured 14 to 22 times with subinhibitory terpinen-4-ol. Overall, these data indicate that tea tree oil and terpinen-4-ol have little impact on the development of antimicrobial resistance and susceptibility.

Survey of the antimicrobial activity of commercially available Australian tea tree (Melaleuca alternifolia) essential oil products in vitro.

OBJECTIVES: The aim of this study was to investigate the antimicrobial activity of a range of commercially available tea tree oil (TTO) products and to evaluate whether formulation plays a significant part in their antiseptic activity. METHODS: The antimicrobial activity of the purchased products and control TTO solutions was assessed against Escherichia coli, Staphylococcus aureus, Salmonella typhimurium, Pseudomonas aeruginosa, and Candida albicans using well diffusion, broth microdilution, and broth macrodilution assays. RESULTS: Zone sizes obtained by the agar well diffusion assay ranged from 0 to 49.8 mm, with the more viscous and lipophilic products producing the smallest zones. Micro- and macrodilution methods showed that eight products had minimum inhibitory concentrations that were lower than the nonformulated TTO control. The remaining three products showed activity equivalent to the TTO control. CONCLUSIONS: In general, the commercially available antiseptic TTO products showed antimicrobial activity that was equivalent to, or greater than the nonformulated TTO control. This suggests that the TTO within these products has retained its antimicrobial activity. Furthermore, the enhanced activity of the products may be attributed to other antimicrobial excipients within the products such as preservatives, or to synergistic antimicrobial interactions between the TTO and other product excipients. The observation that the commercially available antiseptic TTO products tested in this study retained adequate antimicrobial activity emphasizes the importance of considering how product bases and excipients may interact with the active compound during formulation to ensure efficacy of the final product. Finally, the current data suggest that these TTO products may also be active in vivo. However, this can only be determined through further studies and in clinical trials.

Uncontrolled, open-label, pilot study of tea tree (Melaleuca alternifolia) oil solution in the decolonisation of methicillin-resistant Staphylococcus aureus positive wounds and its influence on wound healing.

Many complementary and alternative products are used to treat wounds. The essential oil of Melaleuca alternifolia, tea tree oil, has proven antimicrobial and anti-inflammatory properties, may be useful in methicillin-resistant Staphylococcus aureus (MRSA) decolonisation regimens and is reputed to have 'wound-healing' properties, but more data are required to support these indications. The primary aim of this uncontrolled case series was to assess whether a tea tree oil solution used in a wound cleansing procedure could decolonise MRSA from acute and chronic wounds of mixed aetiology. The secondary aim was to determine if the tea tree oil solution influenced wound healing outcomes. Nineteen participants with wounds suspected of being colonised with MRSA were enrolled in a pilot study. Seven were subsequently shown not to have MRSA and were withdrawn from the study. As many as 11 of the remaining 12 participants were treated with a water-miscible tea tree oil (3·3%) solution applied as part of the wound cleansing regimen at each dressing change. Dressing changes were three times per week or daily as deemed necessary by the study nurse following assessment. One participant withdrew from the study before treatment. No participants were MRSA negative after treatment. After treatment had been implemented, 8 of the 11 treated wounds had begun to heal and reduced in size as measured by computer planimetry. Although this formulation and mode of delivery did not achieve the primary aim of the study, tea tree oil did not appear to inhibit healing and the majority of wounds reduced in size after treatment.

Australasian Society for Infectious Diseases guidelines for the diagnosis and treatment of Clostridium difficile infection.

Clostridium difficile is the most common cause of health care-associated and antibiotic-associated diarrhoea. These guidelines are intended to provide advice to clinicians on the clinical assessment, diagnosis and management of C. difficile infection (CDI). Hypervirulent strains of C. difficile, including PCR ribotype 027 strains recently identified in Australia, have been associated elsewhere with epidemic spread and high rates of severe disease and death. Diagnostic tests include stool culture, polymerase chain reaction-based assays, cell-culture cytotoxicity assays and enzyme immunoassays detecting C. difficile glutamate dehydrogenase, and/or toxin A and/or B. To treat an initial episode and a first recurrence, metronidazole is the preferred antibiotic, with oral vancomycin reserved for severe disease and subsequent recurrences. Surgery should be considered for fulminant disease.

Inhibition of established subcutaneous murine tumour growth with topical Melaleuca alternifolia (tea tree) oil.

PURPOSE: Systemic toxicity coupled with long treatment regimes of approved topical chemotherapeutic agents such as imiquimod and 5-fluorouracil (5-FU) are limiting. There is now more focus on the potential use of topical terpene agents as skin cancer treatments. Here, we show for the first time that topical Melaleuca alternifolia (tea tree) oil (TTO), abundant in terpenes, has in vivo antitumour activity. METHOD: Topical TTO formulations applied to immunocompetent tumour-bearing mice were assessed for antitumour efficacy by monitoring tumour growth and by histological analysis following treatment. RESULTS: Four, daily, topical treatments of 10% TTO/DMSO regressed subcutaneous AE17 mesotheliomas in mice for a period of 10 days and significantly retarded the growth of subcutaneous B16-F10 melanomas. The antitumour effect of topical 10% TTO/DMSO was accompanied by skin irritation similar to other topical chemotherapeutic agents, but unlike other approved topical agents, quickly and completely resolved. Furthermore, we show that topical 10% TTO/DMSO caused an influx of neutrophils and other immune effector cells in the treated area, with no evidence of systemic toxicity. CONCLUSION: TTO combined with an effective carrier significantly inhibited the growth of aggressive, subcutaneous, chemo-resistant tumours in immunocompetent mice. Taken together, these findings highlight the potential of topical TTO as an alternative topical antitumour treatment.

The interaction between respiratory viruses and pathogenic bacteria in the upper respiratory tract of asymptomatic Aboriginal and non-Aboriginal children.

BACKGROUND: Associations between respiratory viruses and the bacterial pathogens Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis may be important in the pathogenesis of otitis media (OM). However, data on asymptomatic identification rates of respiratory viruses are limited, particularly in Indigenous populations, who suffer a high burden of OM. METHODS: We describe the identification of respiratory viruses alone and in combination with pathogenic OM bacteria in 1006 nasopharyngeal aspirates collected from asymptomatic Aboriginal and non-Aboriginal children in a longitudinal community-based cohort study in rural Western Australia. RESULTS: Viruses were identified in 42% of samples from Aboriginal and 32% from non-Aboriginal children. Rhinoviruses were the most frequently identified virus with higher identification rates in Aboriginal (23.6%) than non-Aboriginal children (16.5%; P = 0.003). Rhinoviruses were associated with H. influenzae (odds ratio [OR], 2.24; 95% CI, 1.24-4.07 for Aboriginal children) and M. catarrhalis (OR, 1.94; 95% CI, 1.05-3.57 for Aboriginal children). Adenoviruses were positively associated with H. influenzae in Aboriginal children (OR, 3.30; 95% CI, 1.19-9.09) and M. catarrhalis in non-Aboriginal children (OR, 5.75; 95% CI, 1.74-19.23), but negatively associated with S. pneumoniae in Aboriginal children (OR, 0.39; 95% CI, 0.18-0.84). CONCLUSIONS: We found a high identification rate of rhinoviruses and adenoviruses in asymptomatic children. The associations between these viruses and OM bacteria have implications for preventive strategies targeted at specific pathogens.

Frequencies of resistance to Melaleuca alternifolia (tea tree) oil and rifampicin in Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis.

This study was conducted to determine the frequencies at which single-step mutants resistant to tea tree oil and rifampicin occurred amongst the Gram-positive organisms Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis. For tea tree oil, resistance frequencies were very low at <10(-9). Single-step mutants resistant to tea tree oil were undetectable at two times the minimum inhibitory concentration (MIC) for S. aureus RN4220 and derivative mutator strains or at 3 x MIC for the remaining S. aureus strains, including a clinical meticillin-resistant S. aureus isolate. Similarly, no mutants were recovered at 2x MIC for S. epidermidis or at 1x MIC for E. faecalis. Resistance frequencies determined in vitro for rifampicin (8 x MIC) ranged from 10(-7) to 10(-8) for all isolates, with the exception of the S. aureus mutator strains, which had slightly higher frequencies. These data suggest that Gram-positive organisms such as Staphylococcus and Enterococcus spp. have very low frequencies of resistance to tea tree oil.

Role of the MexAB-OprM efflux pump of Pseudomonas aeruginosa in tolerance to tea tree (Melaleuca alternifolia) oil and its monoterpene components terpinen-4-ol, 1,8-cineole, and alpha-terpineol.

Using a series of efflux mutants of Pseudomonas aeruginosa, the MexAB-OprM pump was identified as contributing to this organism's tolerance to the antimicrobial agent tea tree (Melaleuca alternifolia) oil and its monoterpene components terpinen-4-ol, 1,8-cineole, and alpha-terpineol. These data show that a multidrug efflux system of P. aeruginosa can extrude monoterpenes and related alcohols.