Selecting candidates for pharmacy residencies: A national survey of residency program directors.

WHAT IS KNOWN AND OBJECTIVE: Due to advances in healthcare and treatment options, there is a need for pharmacists with additional post-graduate residency training. With the growing need for residency-trained pharmacists, obtaining a post-graduate pharmacy residency has become more competitive. The objective of this study was to capture the perspectives of post-graduate year 1 residency programme directors (RPDs) in the United States (US) regarding aspects of a candidate's application and interview they found most important when selecting future residents. METHODS: A cross-sectional, electronic survey was distributed via e-mail to PGY-1 pharmacy RPDs in the USA. RPDs were identified via the American Society of Health-System Pharmacists' pharmacy residency directory. Data related to programme demographics, candidate applications and interview evaluations were collected. RPDs' perceptions were captured via a 5-point Likert scale (1 = strongly disagree; 5 = strongly agree). RESULTS AND DISCUSSION: A total of 327 (26.6%) RPDs completed the survey. RPDs highly considered overall compatibility (mean Likert score: 4.9), letters of recommendation (4.6) and letter of interest (4.5) when inviting candidates for on-site interviews. Residency programmes focusing in acute care valued hospital pharmacy work experience more compared to non-acute care-focused residency programmes (4.2 vs 2.9). During the interview, critical thinking ability (4.8), verbal communication (4.8) and overall compatibility (4.9) were viewed as highly important when considering ranking of candidates. WHAT IS NEW AND CONCLUSION: Due to the competitive nature of obtaining a residency programme, insight from RPDs on factors they consider significant when assessing prospective residents is valuable. The results from this study show that a strong letter of intent, letters of recommendations and overall compatibility are considered important by RPDs and should be used by candidates to better prepare themselves for residency applications. Additionally, the candidate should remain knowledgeable about the residency programme and be able to respond to questions asked during the residency interview process.

Treatment of methicillin-sensitive Staphylococcus aureus bacteremia secondary to septic phlebitis using dalbavancin.

WHAT IS KNOWN AND OBJECTIVE: Treatment of bacteremia due to Staphylococcus aureus often requires prolonged therapy leading to increased hospital lengths of stay and associated costs. For certain patients, referral to an outpatient parenteral antimicrobial therapy (OPAT) programme serves as an alternative to increased inpatient length of stay. We report an alternative to OPAT using dalbavancin for the treatment of methicillin-sensitive Staphylococcus aureus (MSSA). CASE SUMMARY: A 54-year-old Caucasian man was brought to the emergency department from a rehabilitation centre with altered mental status and possible seizure. A peripheral intravenous catheter was placed in the left forearm, and the patient was transferred to the intensive care unit (ICU) for management of his acute psychosis, possible seizure and hyponatremia. Seven days into admission, the patient became febrile thought to be secondary to septic phlebitis of the forearm. Blood cultures were taken and organism identification using Nanosphere Verigene® BC-GP rapid diagnostic testing resulted in MSSA. The patient received treatment with cefazolin with a planned treatment duration of 14 days but because of the patient's history of alcohol abuse, psychosis requiring hospitalization via the Baker Act, and history of non-compliance to follow-up appointments, the patient was deemed ineligible for OPAT. Due to the limited treatment options, therapy for MSSA bacteremia was changed on day 6 of cefazolin therapy to dalbavancin to complete the 14-day treatment duration. Blood cultures were negative at the end of treatment and no relapse of infection occurred. WHAT IS NEW AND CONCLUSION: To our knowledge, this is the first case report using dalbavancin in clinical practice for the treatment of MSSA bacteremia secondary to septic phlebitis. This report highlights the potential role of the newer lipoglycopeptides, such as dalbavancin, in treating patients who require long-term parenteral antimicrobial therapy and are ineligible for treatment via OPAT.

Effect of the regional environment on the skin properties and the early wrinkles in young Chinese women.

BACKGROUND: There are ethnic differences in the skin characteristics, also the skin is susceptible to be influenced by the external environment such as UV radiation and the climates. It can be shown that the skin in same race or twins varies by the environment. OBJECTIVES: This study was designed to investigate the skin characteristics and the early wrinkles of young Chinese women from four different regions, and to identify the correlation among the wrinkles, the other skin characteristics, and environmental conditions. METHODS: A total of 441 healthy Chinese women aged between 20 and 35 years participated in the study: 110 from Beijing, 110 from Shanghai, 111 from Wuhan, and 110 from Guangzhou. The skin hydration, sebum contents, TEWL, pH, elasticity, and wrinkles were measured on the crow's feet area. RESULTS: There were regional differences in the skin characteristics and the wrinkles. Beijing women had dry skin and more wrinkles, but Guangzhou women had high sebum contents, low pH, and less wrinkles (P < 0.01). Shanghai women's TEWL and Wuhan's women's skin elasticity were higher compared with that of women from other regions. The wrinkles' form (area, depth, and length) was different from region to region. Beijing women's wrinkles were deep and large, but Guangzhou women's wrinkles were shallow and small. The skin physical parameters that influenced the wrinkles were low sebum content and hydration, high TEWL, and pH (P < 0.05). CONCLUSION: In the Chinese women aged 20-35 years, the skin was influenced by the climates, so they had regionally a different skin. The skin hydration, sebum contents, TEWL, and pH can affect the early wrinkle formation than skin elasticity.

Effect of skin pH for wrinkle formation on Asian: Korean, Vietnamese and Singaporean.

BACKGROUND: Skin pH may be influenced by various factors, such as hydration of stratum corneum, rate of sebum excretion rate, transepidermal water loss (TEWL) and sweating in relation to skin ageing. OBJECTIVE: The aim of this study was to evaluate the correlation between skin pH and wrinkle formation that is directly related to ageing. In addition, we investigated the factors related to skin ageing by comparing the association between skin pH and other skin properties. METHODS: Three hundred volunteers were selected from three countries: Korea, Vietnam and Singapore. Hydration on the stratum corneum, the rate of sebum excretion rate, melanin index, TEWL and skin temperature on the cheek were measured in a controlled room, and wrinkle length and depth using replicas were compared with skin pH variation. RESULTS: The mean and standard deviation of skin surface pH among the three countries were 5.510 ± 0.625. The greatest gap of skin pH that revealed significant differences for skin properties was represented between the Koreans and the Vietnamese. For all three countries, skin hydration, melanin contents, wrinkle length, wrinkle depth and skin temperature were significantly correlated with skin pH. Factors related to skin moisturizing, such as skin hydration, sebum excretion rate and skin temperature, were negatively correlated with skin pH. Wrinkle length and depth decreased as skin pH became more acidic. CONCLUSIONS: Skin properties displayed various values depending on skin pH. In particular, wrinkle formation significantly decreased as skin pH becomes more acidic. We conclude that skin pH is determined by skin properties, such as skin hydration, sebum excretion rate, melanin concentration, TEWL and skin temperature that affects wrinkle formation.

Comparison of the skin biophysical parameters of Southeast Asia females: forehead-cheek and ethnic groups.

BACKGROUND: Regional and ethnic (racial) differences in skin properties are well known. However, regional and racial studies are limited and have studied skin properties using an insufficient number of subjects and limited ethnic groups, except in the case of some recent studies. OBJECTIVE: The aim of this study was (1) to compare the skin biophysical parameter among the large scale of Southeast Asia females group and (2) to compare skin properties of the forehead and cheek. METHODS: We measured and compared seven skin biophysical parameters, such as skin hydration, sebum, skin pH, melanin index, erythema index, skin elasticity and transepidermal water loss (TEWL), of the forehead and cheek of a large population of Indonesian (n = 200), Vietnamese (n = 100) and Singaporean females (n = 97). RESULTS: At the point of site difference, there were significant differences in five biophysical parameters (skin hydration, skin pH, melanin index, erythema index and skin elasticity) in Indonesian females. In Vietnamese and Singaporean women, they were significant differences in five biophysical parameters (skin hydration, skin pH, melanin index, erythema index and TEWL). At the point of ethnic difference, the Indonesian women had the highest skin pH and melanin index between the different ethnic groups. Vietnamese women had the highest skin hydration and TEWL in the forehead, whereas Singaporean women had the highest skin elasticity. CONCLUSION: The skin biophysical parameters are different between the forehead and cheek among Southeast Asian females. It also reveals that the biophysical parameters are different in same racial group.

Analysis of electrical property changes of skin by oil-in-water emulsion components.

OBJECTIVES: As the 'Dry Skin Cycle' produces continuous deterioration, cosmetic xerosis (flaky, dry skin) is one of the major concerns to most consumers. The purpose of this study was to investigate the moisturizing effect of oil-in-water (O/W) emulsion components. There are numerous types of oils, waxes, polyols and surfactants used as ingredients in skincare products. However, the moisturizing effect of each ingredient and understanding each use to make an effective moisturizing products are still not well understood. METHODS: To provide answers to these questions, we investigated the moisturizing effect of widely used 41 components (four different classes) in a simple O/W emulsion using capacitance methods. 106 different single oils, and combinations of oil with oil, wax, humectants, and surfactant were formulated and tested. RESULTS: In this study, we found that most of the O/W emulsion components had hydration effects on the skin. (i) The average relative water content increase (RWCI) rate of a single oil-based emulsion was 11.8 ± 5.2% (SE) and 7.9 ± 6.0% (SE) at 3 and 6 h, respectively. (ii) An oil combination emulsion showed an average RWCI rate similar to that of a single oil-based emulsion, 12.6 ± 6.0% (SE) and 12.1 ± 6.4% (SE) at 3 and 6 h, respectively (iii) A combination of waxes with oil showed an average RWCI rate of 16 ± 5.6% (SE) and 12.4 ± 4.5% (SE) at 3 and 6 h, respectively. (iv) Humectant combinations showed the highest average RWCI rate 28 ± 7.3% (SE) and 22.2 ± 7.5% (SE) at 3 and 6 h, respectively (v) Surfactant combinations had an average RWCI of 10.8 ± 4.5% (SE) and 6.0 ± 4.0% (SE) at 3 and 6 h, respectively. CONCLUSION: Interestingly, it was difficult to find moisturizing power differences among samples in the same group. Only the humectants group showed significant differences among samples. Glycerine and urea showed significant skin hydration effects compared with other humectants. We also found a significant moisturizing effect by analysing the chemical functional groups; amide class had a higher hydration effect than betaines and disaccharides in humectants combination.

Soybean extract showed modulation of retinoic acid-related gene expression of skin and photo-protective effects in keratinocytes.

Soy extracts are well known as medicinal and nutritional ingredients, and exhibit benefits towards human skin including depigmenting or anti-ageing effects. Despite the wrinkle decreasing effects of retinoids on skin as an anti-ageing ingredient, retinoid application can causes photo-sensitive responses such as skin irritation. Thus, their daytime usage is not recommended. The aim of this study is the investigation into the activities of soybean extract as an anti-ageing ingredient and their comparison to retinoids in this respect. Soybean extract decreased the relative ratio of MMP-1/TIMP-1 mRNA to the same degree as retinoic acid in normal human fibroblasts. It also affected mRNA levels of HAS2 and CRABP2 in normal human keratinocytes. Furthermore, we investigated its effect on mRNA expression of histidase, an enzyme that converts histidine into urocanic acid, the main UV light absorption factor of the stratum corneum. Unlike the complete inhibition of histidase exhibited by the mRNA expression of retinoic acid, the effect of soybean extract on histidase gene expression was weaker in normal human keratinocytes. Also, soybean extract pretreatment inhibited UVB-induced cyclobutane pyrimidine dimer formation dose-dependently in normal human keratinocytes. In this study, we found that soybean extract modulated retinoic acid-related genes and showed photo-protective effects. Our findings suggest that soybean extract could be an anti-ageing ingredient that can be safely used under the sunlight.

Baloxavir marboxil: a novel cap-dependent endonuclease (CEN) inhibitor for the treatment of acute uncomplicated influenza.

Baloxavir marboxil is a newly approved antiviral agent with activity against influenza via a novel mechanism of action of inhibition of cap-dependent endonuclease (CEN). The novel agent was approved in October of 2018 in the United States for the treatment of acute uncomplicated influenza A and B in patients aged 12 years or older. Baloxavir is given as a single weight-based dose of 40 mg orally once for patients weighing less than 80 kg and 80 mg orally once for those weighing 80 kg or more within 48 hours of symptom onset. In comparison with current therapy, baloxavir is as effective in decreasing time to symptom alleviation as the drug of choice, oseltamivir, and significantly reduces viral load 1 day after treatment compared with placebo and oseltamivir. In safety analyses baloxavir was well tolerated with only mild adverse events reported (nausea, headache, diarrhea, bronchitis, nasopharyngitis), thus providing a safe and reliable alternative option to current therapy for acute uncomplicated influenza. Further studies are being conducted to evaluate the use of baloxavir in additional patient populations including pediatric patients less than 12 years of age and patients who are at high risk of complications related to influenza.

Letermovir for prophylaxis of cytomegalovirus in allogeneic hematopoietic stem cell recipients.

Letermovir is a new antiviral agent with activity against human cytomegalovirus (CMV). Letermovir works as an inhibitor of the CMV DNA terminase complex which further inhibits viral DNA processing and packaging. Letermovir is available both orally and intravenously in 480-mg and 240-mg dosage forms, and is approved for use in the prophylaxis of CMV infection and disease in CMV-seropositive recipients of allogeneic hematopoietic stem cell transplant (HSCT) over the age of 18. The recommended dose is 480 mg p.o./i.v. once daily initiated between day 0 through day 28 post-allogeneic HSCT and continued through day 100 post-transplantation; the dose should be reduced to 240 mg daily if coadministered with cyclosporine. Letermovir is metabolized primarily by hepatic OATP1B1/3 and is not recommended for patients with severe hepatic impairment (Child-Pugh class C). Renal dosage adjustments are not warranted until a creatinine clearance (CrCl) of less than 10 mL/min; however, serum creatinine should be monitored when administered to patients with a CrCl of less than 50 mL/min. Cross-resistance with other useful antiviral agents in the treatment of CMV has not been observed. Additionally, letermovir is active against DNA polymerase inhibitor-resistant viral strains. Letermovir has shown promising clinical efficacy and is generally well tolerated, thus providing a favorable new option in the prophylaxis of CMV infection and disease.

Heplisav-B vaccination for the prevention of hepatitis B virus infection in adults in the United States.

The prevalence of hepatitis B virus (HBV) infections is a worldwide issue that can lead to both acute and chronic complications with increased morbidity and mortality in affected individuals. Current methods of preventing HBV infections primarily include building patient immunity through administration of hepatitis B vaccinations starting at birth. Certain at-risk individuals, including those with occupational exposure to pathogenic bodily fluids, those who are sexually active or intravenous drug users, are recommended to receive some form of hepatitis B vaccination. The current standard of hepatitis B vaccination in the United States is the Engerix-B vaccine, which consists of a three-dose regimen over a 6-month time period. A new hepatitis B vaccine, Heplisav-B, has been approved for adults in the United States and requires only two doses over 1 month. The unique dosing schedule of Heplisav-B provides the potential for increasing patient compliance and therefore can aid in the effort toward protecting individuals from developing an HBV infection. Results from clinical trials showed that Heplisav-B compared favorably with Engerix-B in safety and efficacy profiles. This paper provides a review of the pharmacology, safety, clinical trials and indications for use for the Heplisav-B vaccine in the United States.

Return of the tetracyclines: omadacycline, a novel aminomethylcycline antimicrobial.

Omadacycline is a novel aminomethylcycline antimicrobial agent that is available in both oral and intravenous formulations. The distinguishing structural characteristics of omadacycline from other tetracyclines allow for its continued antimicrobial activity in the presence of traditional tetracycline resistance mechanisms (efflux pumps and ribosomal protection proteins). Omadacycline has been found to have potent activity against antibiotic-resistant pathogens including methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, extended spectrum beta-lactamase-producing Escherichia coli and multidrug-resistant Streptococcus pneumoniae. Currently available data indicate that omadacycline is generally well tolerated with the most common adverse effects being gastrointestinal symptoms. Omadacycline seems to be a promising new agent for the treatment of community-acquired bacterial pneumonia and acute bacterial skin and skin structure infections. Studies for the treatment of cystitis in adult females are currently underway, and future results of these studies will further help delineate the antibacterial role of omadacycline.

Characteristics of antimicrobial stewardship programmes in rural East Texas hospitals.

INTRODUCTION: Antimicrobial stewardship programmes (ASPs) serve as the primary method to prevent and manage the development of antimicrobial resistance. Rural settings may lack the recommended personnel and resources needed to provide antimicrobial stewardship services. METHODS: An electronic survey was distributed via e-mail to pharmacy directors or antimicrobial stewardship programme directors of licensed hospitals within Public Health Region 4/5N of East Texas. RESULTS: Sixty percent of ASPs were established <12 months prior to the survey administration. All ASPs had pharmacist involvement, with only one (5%) having formal infectious diseases (ID) training through postgraduate education. Ninety percent of ASPs had a physician champion, with five (27.8%) physicians having formal ID training. Most institutions lacked one or more recommended antimicrobial stewardship practices. When compared with ASPs established for <12 months, ASPs existing for at least 12 months were more likely to have protocols to change antimicrobials from intravenous to enteral forms (100% vs 50%, P = 0.042), provide education to patients and families on appropriate antimicrobial use (87.5% vs 33.3%, P = 0.028), and track antimicrobial purchasing costs (87.5% vs 33.3%, P = 0.028). CONCLUSIONS: Institutions in rural settings require additional resources, personnel, and time to implement ASPs and perform various antimicrobial stewardship practices.

Viable, but non-culturable, state of a green fluorescence protein-tagged environmental isolate of Salmonella typhi in groundwater and pond water.

An environmental isolate of Salmonella typhi was chromosomally marked with a gfp gene encoding green fluorescence protein (GFP) isolated from Aequorea victoria. The hybrid transposon mini Tn5 gfp was transconjugated from E. coli to S. typhi, resulting in constitutive GFP production. The survival of S. typhi GFP155 introduced into groundwater and pond water microcosms was examined by GFP-based plate counts, total cell counts, and direct viable counts. A comparison between GFP-based direct viable counts and plate counts was a good method for verifying the viable, but non-culturable (VBNC), state of S. typhi. The entry into a VBNC state of S. typhi was shown in all microcosms. S. typhi survived longer in groundwater than in pond water as both a culturable and a VBNC state.

Green fluorescent protein-based direct viable count to verify a viable but non-culturable state of Salmonella typhi in environmental samples.

The gfp-tagging method and lux-tagging method were compared to select a better method for verifying a viable but nonculturable (VBNC) state of bacteria in the environment. An environmental isolate of Salmonella typhi was chromosomally marked with a gfp gene encoding green fluorescent protein (GFP). The hybrid transposon mini-Tn5 gfp was transconjugated from E. coli to S. typhi. Using the same method, S. typhi was chromosomally marked with luxAB genes encoding luciferase. The survival of gfp-tagged S. typhi introduced into groundwater microcosms was examined by GFP-based plate count, total cell count, and a direct viable count method. In microcosms containing lux-tagged S. typhi, luminescence-based plate count and the measurement of bioluminescence of each microcosm sample were performed. In microcosms containing lux-tagged S. typhi, viable but nonculturable cells could not be detected by using luminometry. As no distinguishable luminescence signals from the background signals were found in samples containing no culturable cells, a VBNC state of S. typhi could not be verified in lux-based systems. However, comparison between GFP-based direct viable counts and plate counts was a good method for verifying the VBNC state of S. typhi. Because GFP-based direct viable count method provided a direct and precise estimation of viable cells of introduced bacteria into natural environments, it can be used for verifying the VBNC state of bacteria in environmental samples.

Heavy contamination of a subsurface aquifer and a stream by livestock wastewater in a stock farming area, Wonju, Korea.

A survey of groundwater and stream water quality was undertaken in a stock farming area where livestock wastewater infiltrates into sandy unsaturated zones and saturated bedrock aquifers containing fractures. To determine the degree of contamination and track the effect of livestock wastewater on groundwater and stream water quality, the population of indicator bacteria (total coliforms, fecal coliforms, fecal streptococci, Staphylococcus spp., and sulfite-reducing clostridia) together with relevant physicochemical parameters were monitored along the wastewater flow-pathways over a 19-month period. The stream water was severely contaminated with livestock wastewater. Nearly all physicochemical and bacteriological parameters in the stream water were much greater than those in the groundwater. Nitrate-N concentrations ranged from 10.0 to 20.0 mg l(-1) in boreholes located downstream (site C) from the livestock waste disposal site, while those in the background borehole (W2) were below 1.0 mg l(-1). Densities of indicator bacteria in boreholes at site C were two or three orders of magnitude higher than those in W2 borehole. In boreholes located downstream from the livestock waste disposal site, the concentration of ammonium-N, nitrate-N, and pollution indicator bacteria increased as groundwater level rose due to infiltration of rainwater. In W2 borehole, however, physicochemical parameters and the number of pollution indicator bacteria had no correlation with the groundwater level. Collectively, these results suggest that the deep aquifers were heavily contaminated with infiltrated livestock wastewater, which consequently must be adequately treated to minimize groundwater pollution.

Preparation and characterization of Japanese encephalitis virus vaccine loaded poly(L-lactide-co-glycolide) microspheres for oral immunization.

Japanese encephalitis virus (JEV) vaccine loaded biodegradable poly(L-lactide-co-glycolide) (PLGA) microspheres (MSs) were prepared by W/O/W solvent evaporation method to study the possibility for oral vaccination. The influence of several preparation parameters as stirring rate, types and concentration of emulsifier, PLGA concentration, etc. has been observed on size, size distribution and biodegradation. The mean MSs size decreased when the agitation speed and the concentration of emulsifier were increased, and when the PLGA concentration was decreased. The surface morphology of porous and nonporous JEV vaccine loaded PLGA MSs was prepared from polyvinylalcohol and sodium dodecyl sulfate as used emulsifiers, respectively. From the assay of lactic acid and scanning electron microscope observation, it can be suggested that the rate of biodegradation of nonporous MSs was slower than that of porous surface morphology due to lower the surface area. Mechanisms of the formation of porous and nonporous surface by different types of emulsifier, and the biodegradation of MSs have been proposed. Also, the size and size distribution of JEV vaccine loaded PLGA MSs were discussed to apply oral vaccination through the Peyer's patches across the gastrointestinal tract.

Preparation and characterization of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) microspheres for the sustained release of 5-fluorouracil.

Biodegradable microspheres were prepared with poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV, 85:15 by mole ratio of hydroxybutyrate to hydroxyvalerate) by an water-in-oil-in-water (W/O/W), oil-in-water (O/W) and oil-in-oil (O/O) solvent evaporation method for the sustained release of anti-cancer drug, 5-fluorouracil (5-FU) with controlling the fabrication conditions. The shape of microspheres prepared was relatively rough due to highly crystalline property of PHBV and spherical. The efficiency of 5-FU loading into the PHBV microsphere with O/O method was over 80% compared to that 7% for microspheres by O/W method and below 1% for microspheres by a conventional W/O/W method. However, the most desirable release pattern can be achieved from the O/W method due to the cosolvent effect. The effects of preparation conditions such as the type and amount of surfactant, initial amount of loaded drug, the temperature of solvent evaporation, and etc. on the morphology for W/O/W method were investigated. Possible mechanisms of the desirable sustained release pattern for O/W system have been proposed.

Aurantimonas manganoxydans, sp. nov. and Aurantimonas litoralis, sp. nov.: Mn(II) oxidizing representatives of a globally distributed clade of alpha-Proteobacteria from the order Rhizobiales.

Several closely related Mn(II)-oxidizing alpha-Proteobacteria were isolated from very different marine environments: strain SI85-9A1 from the oxic/anoxic interface of a stratified Canadian fjord, strain HTCC 2156 from the surface waters off the Oregon coast, and strain AE01 from the dorsal surface of a hydrothermal vent tubeworm. 16S rRNA analysis reveals that these isolates are part of a tight phylogenetic cluster with previously characterized members of the genus Aurantimonas. Other organisms within this clade have been isolated from disparate environments such as surface waters of the Arctic and Mediterranean seas, a deep-sea hydrothermal plume, and a Caribbean coral. Further analysis of all these strains revealed that many of them are capable of oxidizing dissolved Mn(II) and producing particulate Mn(III/IV) oxides. Strains SI85-9A1 and HTCC 2156 were characterized further. Despite sharing nearly identical 16S rRNA gene sequences with the previously described Aurantimonas coralicida, whole genome DNA-DNA hybridization indicated that their overall genomic similarity is low. Polyphasic phenotype characterization further supported distinguishing characteristics among these bacteria. Thus SI85-9A1 and HTCC 2156 are described as two new species within the family 'Aurantimionadaceae': Aurantimonas manganoxydans sp. nov. and Aurantimonas litoralis sp. nov. This clade of bacteria is widely distributed around the globe and may be important contributors to Mn cycling in many environments. Our results highlight the difficulty in utilizing 16S rRNA-based approaches to investigate the microbial ecology of Mn(II) oxidation.

Dilution-to-extinction culturing of psychrotolerant planktonic bacteria from permanently ice-covered lakes in the McMurdo Dry Valleys, Antarctica.

Lakes in the McMurdo Dry Valleys of Antarctica are characterized by a permanent ice cover and little or no anthropogenic influence. Although bacterial cultures have been obtained from these habitats, recent culture-independent studies indicate that the most abundant microbes in these systems are not yet cultivated. By using dilution-to-extinction cultivation methods with sterilized and nutrient-amended lake water as media, we isolated 148 chemotrophic psychrotolerant bacterial cultures from fresh surface water of Lake Fryxell and the east lobe of Lake Bonney and the hypersaline, suboxic bottom water from the west lobes of Lake Bonney. Screening of the 16S ribosomal ribonucleic acid (rRNA) genes of the cultures by restriction fragment length polymorphism (RFLP) yielded 57 putatively pure psychrotolerant, slow growing cultures grouped into 18 clusters. The sequencing of 16S rRNA genes of randomly selected representatives of each RFLP cluster revealed that the corresponding isolates belong to the Alphaproteobacteria (six RFLP patterns), Betaproteobacteria (six RFLP patterns), Bacteroidetes (four RFLP patterns), and Actinobacteria (two RFLP patterns). Phylogenetic analysis of the sequences showed that the vast majority of the isolates were not closely related to previously described species. Thirteen of 18 RFLP patterns shared a 16S ribosomal deoxyribonucleic acid sequence similarity of 97% or less with the closest described species, and four isolates had a sequence similarity of 93% or less with the nearest described species. Phylogenetic analysis showed that these sequences were representatives of deeply branching organisms in the respective phylum. A comparison of the isolates with 16S rRNA clone libraries prepared from the same environments showed substantial overlap, indicating that dilution-to-extinction culturing in natural lake water media can help isolate some of the most abundant organisms in these perennially ice-covered lakes.

Detection of mega plasmid from polycyclic aromatic hydrocarbon-degrading Sphingomonas sp. strain KS14.

Polycyclic aromatic hydrocarbon (PAH) degrading Sphingomonas sp. strain KS14 was isolated from soil. Strain KS14 was able to utilize phenanthrene and naphthalene as sole source of carbon and energy, and mineralize phenanthrene to carbon dioxide. Strain KS14 cometabolically degraded pyrene using phenanthrene as secondary growth substrate. A large degradative plasmid (>500 kb) was detected from the strain KS14. This study suggests that this mega plasmid could be responsible for the degradation of PAH by strain KS14.