Semisynthesis, Characterization, and Biological Evaluation of Fluorinated Analogues of the Spirobisnaphthalene, Diepoxin-η

Diepoxin-η (1) is a cytotoxic fungal metabolite belonging to the spirobisnaphthalene structural class. In this study, four mono fluorinated analogues (2-5) of diepoxin-η (1) were semisynthesized in a single-step by selectively fluorinating the naphthalene moiety with Selectfluor. The structures of 2-5 were elucidated using a set of spectroscopic and spectrometric techniques and were further confirmed by means of TDDFT-ECD and isotropic shielding tensors calculations. Compounds 2-5 showed equipotent cytotoxic activity to 1 when tested against OVCAR3 (ovarian) and MDA-MB-435 (melanoma) cancer cell lines with IC50 values that range from 5.7-8.2 μM.

Robust and Transparent Silver Oxide Coating Fabricated at Room Temperature Kills Clostridioides difficile Spores, MRSA, and Pseudomonas aeruginosa

Antimicrobial coatings can inhibit the transmission of infectious diseases when they provide a quick kill that is achieved long after the coating application. Here, we describe the fabrication and testing of a glass coating containing Ag2O microparticles that was prepared from sodium silicate at room temperature. The half-lives of both methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa on this coating are only 2-4 min. The half-life of Clostridioides difficile spores is about 9-12 min, which is extremely short for a spore. Additional tests on MRSA demonstrate that the coating retains its antimicrobial activity after abrasion and that an increased loading of Ag2O leads to a shorter half-life. This coating combines the properties of optical transparency, robustness, fast kill, and room temperature preparation that are highly desirable for an antimicrobial coating.

Premise Plumbing Pipe Materials and In-Building Disinfectants Shape the Potential for Proliferation of Pathogens and Antibiotic Resistance Genes

In-building disinfectants are commonly applied to control the growth of pathogens in plumbing, particularly in facilities such as hospitals that house vulnerable populations. However, their application has not been well optimized, especially with respect to interactive effects with pipe materials and potential unintended effects, such as enrichment of antibiotic resistance genes (ARGs) across the microbial community. Here, we used triplicate convectively mixed pipe reactors consisting of three pipe materials (PVC, copper, and iron) for replicated simulation of the distal reaches of premise plumbing and evaluated the effects of incrementally increased doses of chlorine, chloramine, chlorine dioxide, and copper-silver disinfectants. We used shotgun metagenomic sequencing to characterize the resulting succession of the corresponding microbiomes over the course of 37 weeks. We found that both disinfectants and pipe material affected ARG and microbial community taxonomic composition both independently and interactively. Water quality and total bacterial numbers were not found to be predictive of pathogenic species markers. One result of particular concern was the tendency of disinfectants, especially monochloramine, to enrich ARGs. Metagenome assembly indicated that many ARGs were enriched specifically among the pathogenic species. Functional gene analysis was indicative of a response of the microbes to oxidative stress, which is known to co/cross-select for antibiotic resistance. These findings emphasize the need for a holistic evaluation of pathogen control strategies for plumbing.

Influence of pipe materials on in-building disinfection of P. aeruginosa and A. baumannii in simulated hot water plumbing

A framework is needed to account for interactive effects of plumbing materials and disinfectants on opportunistic pathogens (OPs) in building water systems. Here we evaluated free chlorine, monochloramine, chlorine dioxide, and copper-silver ionization (CSI) for controlling Pseudomonas aeruginosa and Acinetobacter baumannii as two representative OPs that colonize hot water plumbing, in tests using polyvinylchloride (PVC), copper-PVC, and iron-PVC convectively-mixed pipe reactors (CMPRs). Pipe materials vulnerable to corrosion (i.e., iron and copper) altered the pH, dissolved oxygen, and disinfectant levels in a manner that influenced growth trends of the two OPs and total bacteria. P. aeruginosa grew well in PVC CMPRs, poorly in iron-PVC CMPRs, and was best controlled by CSI disinfection, whereas A. baumannii showed the opposite trend for pipe material and was better controlled by chlorine and chlorine dioxide. Various scenarios were identified in which pipe material and disinfectant can interact to either hinder or accelerate growth of OPs, illustrating the difficulties of controlling OPs in portions of plumbing systems experiencing warm, stagnant water.

The risk of pulmonary NTM infections and water-quality constituents among persons with cystic fibrosis in the United States, 2010-2019

Rationale

The prevalence of nontuberculous mycobacterial (NTM) pulmonary disease varies geographically in the United States. Previous studies indicate that the presence of certain water-quality constituents in source water increases NTM infection risk.

Objective

To identify water-quality constituents that influence the risk of NTM pulmonary infection in persons with cystic fibrosis in the United States.

Methods

We conducted a population-based case-control study using NTM incidence data collected from the Cystic Fibrosis Foundation Patient Registry during 2010-2019. We linked patient zip code to the county and associated patient county of residence with surface water data extracted from the Water Quality Portal. We used logistic regression models to estimate the odds of NTM infection as a function of water-quality constituents. We modeled two outcomes: pulmonary infection due to Mycobacterium avium complex (MAC) and Mycobacterium abscessus species.

Results

We identified 484 MAC cases, 222 M. abscessus cases and 2816 NTM-negative cystic fibrosis controls resident in 11 states. In multivariable models, we found that for every 1-standardized unit increase in the log concentration of sulfate and vanadium in surface water at the county level, the odds of infection increased by 39% and 21%, respectively, among persons with cystic fibrosis with MAC compared with cystic fibrosis-NTM-negative controls. When modeling M. abscessus as the dependent variable, every 1-standardized unit increase in the log concentration of molybdenum increased the odds of infection by 36%.

Conclusions

These findings suggest that naturally occurring and anthropogenic water-quality constituents may influence the NTM abundance in water sources that supply municipal water systems, thereby increasing MAC and M. abscessus infection risk.

Facile Implementation of Antimicrobial Coatings through Adhesive Films (Wraps) Demonstrated with Cuprous Oxide Coatings

Antimicrobial coatings have a finite lifetime because of wear, depletion of the active ingredient, or surface contamination that produces a barrier between the pathogen and the active ingredient. The limited lifetime means that facile replacement is important. Here, we describe a generic method for rapidly applying and reapplying antimicrobial coatings to common-touch surfaces. The method is to deposit an antimicrobial coating on a generic adhesive film (wrap), and then to attach that modified wrap to the common-touch surface. In this scenario, the adhesion of the wrap and antimicrobial efficacy are separated and can be optimized independently. We demonstrate the fabrication of two antimicrobial wraps, both using cuprous oxide (Cu₂O) as the active ingredient. The first uses polyurethane (PU) as the polymeric binder and the second uses polydopamine (PDA). Our antimicrobial PU/Cu₂O and PDA/Cu₂O wraps, respectively, kill >99.98% and >99.82% of the human pathogen, P. aeruginosa, in only 10 min, and each of them kill >99.99% of the bacterium in 20 min. These antimicrobial wraps can be removed and replaced on the same object in <1 min with no tools. Wraps are already frequently used by consumers to coat drawers or cars for aesthetic or protective purposes.

Porous Antimicrobial Coatings for Killing Microbes within Minutes

Antimicrobial coatings can be used to reduce the transmission of infectious agents that are spread by contact. An effective coating should kill microbes in the time between users, which is sometimes minutes or less. Fast killing requires fast transport, and our proposed method of fast transport is a porous coating where the contaminated liquid imbibes (infiltrates) into the pores to achieve rapid contact with active material inside the pores. We test the hypothesis that a porous antimicrobial coating will enable faster inactivation of microorganisms than a planar coating of the same material. We use hydrophilic pores with dimensions of 5-100 μm such that liquid droplets imbibe in seconds, and from there transport distances and times are short, defined by the pore size rather than the droplet size. Our coating has two levels of structure: (A) a porous scaffold and (B) an antimicrobial coating within the pore structure containing the active ingredient. Two scaffolds are studied: stainless steel and poly(methyl methacrylate) (PMMA). The active ingredient is electrolessly deposited copper. To enhance adhesion and growth of copper, a layer of polydopamine (PDA) is deposited on the scaffold prior to deposition of the copper. This porous copper coating kills 99.84% of Pseudomonas aeruginosa within 3 min, which is equivalent to a half-life of 27 s. In contrast, the same layer of PDA/copper on a nonporous coating kills 79.65% in the same time frame, consistent with the hypothesis that the killing rate is increased by the addition of porosity. Using the porous PMMA scaffold, the porous antimicrobial coating kills >99.99% P. aeruginosa in 5 min, which is equivalent to a half-life of 21 s. The higher rate of kill on the porous antimicrobial solid is appropriate for hindering the spread of infectious agents on common-use objects.

Environmental risk of nontuberculous mycobacterial infection: Strategies for advancing methodology

The National Institute of Allergy and Infectious Diseases organized a symposium in June 2022, to facilitate discussion of the environmental risks for nontuberculous mycobacteria exposure and disease. The expert researchers presented recent studies and identified numerous research gaps. This report summarizes the discussion and identifies six major areas of future research related to culture-based and culture independent laboratory methods, alternate culture media and culturing conditions, frameworks for standardized laboratory methods, improved environmental sampling strategies, validation of exposure measures, and availability of high-quality spatiotemporal data.

Nontuberculous mycobacteria in the environment

The nontuberculous mycobacteria (NTM) are normal inhabitants of soils and waters and thereby surround humans due to their presence in water that is distributed to homes, apartments, offices, hospitals and long-term care facilities in pipes. The NTM are not contaminants of drinking water, rather they are colonists ideally adapted to growth and persistence in natural waters. Further those adaptations also favor NTM survival, persistence, and growth in drinking water systems. Thereby, NTM surround humans. The NTM love plumbing as it offers a high surface to volume ratio, ideal for surface adherence and biofilm formation. As a consequence, these slow growing bacteria are not flushed out by flowing water. Factors that support NTM growth and persistence in drinking water include: disinfectant-resistance, growth at low organic matter content (oligotrophic), surface attachment and biofilm formation, growth at low oxygen content (stagnant water), and desiccation-tolerance. A major determinant of the ecology of NTM is the lipid-rich outer membrane. The outer membrane provides a hydrophobic barrier that is relatively impermeable. Although the outer membrane reduces influx of nutrients, it also impedes transport of hydrophilic disinfectants (e.g., chlorine) and antibiotics. NTM are quite adaptable: able to grow in fresh or brackish natural waters and able to induce a high-temperature-resistant state.

Polychlorinated cyclopentenes from a marine derived Periconia sp. (strain G1144)

Studies on an organic extract of a marine fungus, Periconia sp. (strain G1144), led to the isolation of three halogenated cyclopentenes along with the known and recently reported rhytidhyester D; a series of spectrometric and spectroscopic techniques were used to elucidate these structures. Interestingly, two of these compounds represent tri-halogenated cyclopentene derivatives, which have been observed only rarely from Nature. The relative and absolute configurations of the compounds were established via mass spectrometry (MS), nuclear magnetic resonance (NMR) spectroscopy, Mosher's esters method, optical rotation and GIAO NMR calculations, including correlation coefficient calculations and the use of both DP4+ and dJ DP4 analyses. Several of the isolated compounds were tested for activity in anti-parasitic, antimicrobial, quorum sensing inhibition, and cytotoxicity assays and were shown to be inactive.

Desiccation-Tolerance of Mycobacterium avium, Mycobacterium intracellulare, Mycobacterium chimaera, Mycobacterium abscessus and Mycobacterium chelonae

Desiccation-tolerance of cells of four strains of Mycobacterium chimaera and individual strains of Mycobacterium avium, Mycobacterium intracellulare, Mycobacterium abscessus, and Mycobacterium chelonae were measured by two methods. The survival of water-acclimated cells both in filter paper and on the surface of stainless-steel coupons were measured. In filter paper at 40% relative humidity at 25 °C, survival of patient isolates of M. avium and M. chimaera cells was 28% and 34% after 21 days of incubation, whereas it was 100% for the Sorin 3T isolate of M. chimaera. On stainless-steel biofilms after 42 days of incubation at 40% relative humidity at 25 °C, survival of water-acclimated cells of M. intracellulare was above 100%, while M. chelonae cells did not survive beyond 21 days, and survival of water-acclimated cells of M. avium and M. abscessus was 18% and 14%, respectively. On stainless-steel coupons, survival of patient and Sorin 3T isolates of M. chimaera was quite similar, specifically between 14% and 28% survival, after 42 days of incubation at 40% relative humidity at 25 °C. The experiments would support the hypothesis that some nontuberculous mycobacterial species are relatively desiccation-tolerant, whereas others are not. Further, long-term survival of the two M. chimaera strains is consistent with the presence of that species in Sorin 3T heater-coolers shipped throughout the world.

Tenets of a holistic approach to drinking water-associated pathogen research, management, and communication

In recent years, drinking water-associated pathogens that can cause infections in immunocompromised or otherwise susceptible individuals (henceforth referred to as DWPI), sometimes referred to as opportunistic pathogens or opportunistic premise plumbing pathogens, have received considerable attention. DWPI research has largely been conducted by experts focusing on specific microorganisms or within silos of expertise. The resulting mitigation approaches optimized for a single microorganism may have unintended consequences and trade-offs for other DWPI or other interests (e.g., energy costs and conservation). For example, the ecological and epidemiological issues characteristic of Legionella pneumophila diverge from those relevant for Mycobacterium avium and other nontuberculous mycobacteria. Recent advances in understanding DWPI as part of a complex microbial ecosystem inhabiting drinking water systems continues to reveal additional challenges: namely, how can all microorganisms of concern be managed simultaneously? In order to protect public health, we must take a more holistic approach in all aspects of the field, including basic research, monitoring methods, risk-based mitigation techniques, and policy. A holistic approach will (i) target multiple microorganisms simultaneously, (ii) involve experts across several disciplines, and (iii) communicate results across disciplines and more broadly, proactively addressing source water-to-customer system management.

Transparent Anti-SARS-CoV-2 and Antibacterial Silver Oxide Coatings

Transparent antimicrobial coatings can maintain the aesthetic appeal of surfaces and the functionality of a touch-screen while adding the benefit of reducing disease transmission. We fabricated an antimicrobial coating of silver oxide particles in a silicate matrix on glass. The matrix was grown by a modified Stöber sol-gel process with vapor-phase water and ammonia. A coating on glass with 2.4 mg of Ag2O per mm2 caused a reduction of 99.3% of SARS-CoV-2 and >99.5% of Pseudomonas aeruginosa, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus compared to the uncoated glass after 1 h. We envisage that screen protectors with transparent antimicrobial coatings will find particular application to communal touch-screens, such as in supermarkets and other check-out or check-in facilities where a number of individuals utilize the same touch-screen in a short interval.

Transparent and Sprayable Surface Coatings that Kill Drug-Resistant Bacteria Within Minutes and Inactivate SARS-CoV-2 Virus

Antimicrobial coatings are one method to reduce the spread of microbial diseases. Transparent coatings preserve the visual properties of surfaces and are strictly necessary for applications such as antimicrobial cell phone screens. This work describes transparent coatings that inactivate microbes within minutes. The coatings are based on a polydopamine (PDA) adhesive, which has the useful property that the monomer can be sprayed, and then the monomer polymerizes in a conformal film at room temperature. Two coatings are described (1) a coating where PDA is deposited first and then a thin layer of copper is grown on the PDA by electroless deposition (PDA/Cu) and (2) a coating where a suspension of Cu2O particles in a PDA solution is deposited in a single step (PDA/Cu2O). In the second coating, PDA menisci bind Cu2O particles to the solid surface. Both coatings are transparent and are highly efficient in inactivating microbes. PDA/Cu kills >99.99% of Pseudomonas aeruginosa and 99.18% of methicillin-resistant Staphylococcus aureus (MRSA) in only 10 min and inactivates 99.98% of SARS-CoV-2 virus in 1 h. PDA/Cu2O kills 99.94% of P. aeruginosa and 96.82% of MRSA within 10 min and inactivates 99.88% of SARS-CoV-2 in 1 h.

Ecology of Nontuberculous Mycobacteria

Nontuberculous mycobacteria (NTM) are opportunistic human pathogens that are widespread in the human environment. In fact, NTM surround humans. The basis for their widespread presence in soils and natural and human-engineered waters lies primarily in their disinfectant resistance, biofilm formation, and adaptability to fluctuating environmental conditions. As NTM in drinking water surround humans, a major route of infection is through aerosols. The characteristics of NTM, including resistance to disinfection, adherence to surfaces and biofilm formation, present challenges to contemporary water treatment processes developed for control of Escherichia coli and fecal coliforms.

Mapping the Terrain for Pathogen Persistence and Proliferation in Non-potable Reuse Distribution Systems: Interactive Effects of Biofiltration, Disinfection, and Water Age

Diverse pathogens can potentially persist and proliferate in reclaimed water distribution systems (RWDSs). The goal of this study was to evaluate interactive effects of reclaimed water treatments and water age on persistence and proliferation of multiple fecal (e.g., Klebsiella, Enterobacter) and non-fecal (e.g., Legionella, mycobacteria) gene markers in RWDSs. Six laboratory-scale RWDSs were operated in parallel receiving the influent with or without biologically active carbon (BAC) filtration + chlorination, chloramination, or no disinfectant residual. After 3 years of operation, the RWDSs were subject to sacrificial sampling and shotgun metagenomic sequencing. We developed an in-house metagenome-derived pathogen quantification pipeline, validated by quantitative polymerase chain reaction and mock community analysis, to estimate changes in abundance of ∼30 genera containing waterborne pathogens. Microbial community composition in the RWDS bulk water, biofilm, and sediments was clearly shaped by BAC filtration, disinfectant conditions, and water age. Key commonalities were noted in the ecological niches occupied by fecal pathogen markers in the RWDSs, while non-fecal pathogen markers were more varied in their distribution. BAC-filtration + chlorine was found to most effectively control the widest range of target genera. However, filtration alone or chlorine secondary disinfection alone resulted in proliferation of some of these genera containing waterborne pathogens.

Three diketomorpholines from a Penicillium sp. (strain G1071)

Three previously undescribed diketomorpholine natural products, along with the known phenalenones, herqueinone and norherqueinone, were isolated from the mycoparasitic fungal strain G1071, which was identified as a Penicillium sp. in the section Sclerotiora. The structures were established by analyzing NMR data and mass spectrometry fragmentation patterns. The absolute configurations of deacetyl-javanicunine A, javanicunine C, and javanicunine D, were assigned by examining ECD spectra and Marfey's analysis. The structural diversity generated by this fungal strain was interesting, as only a few diketomorpholines (~17) have been reported from nature.

Identification of the Target for a Transition Metal-α-Amino Acid Complex Antibiotic Against Mycobacterium smegmatis

Spontaneous mutants of Mycobacterium smegmatis strain mc²155 resistant to 1-PG (iridium-L-phenylglycine complex), an antimycobacterial antibiotic, were isolated. Based on the discovery that some 1-PG-resistant mutants (1-PG^R) were also resistant to high concentrations of clarithromycin (≥250 μg/ml), but no other anti-mycobacterial antibiotics, the 23S rRNA region spanning the peptidyl transferase domain was sequenced and mutations shown to be localized in the peptidyl transferase domain of the 23S rRNA gene. Measurements showed that 1-PG bound to ribosomes isolated from the 1-PG-sensitive parental strain, but the ribosome binding values for the 1-PG^R mutant reduced.

Living with Legionella and Other Waterborne Pathogens

Legionella spp. and other opportunistic premise plumbing pathogens (OPPPs), including Pseudomonas aeruginosa, Mycobacterium avium, Stenotrophomonas maltophilia, and Acinetobacter baumannii, are normal inhabitants of natural waters, drinking water distribution systems and premise plumbing. Thus, humans are regularly exposed to these pathogens. Unfortunately, Legionella spp. and the other OPPPs share a number of features that allow them to grow and persist in premise plumbing. They form biofilms and are also relatively disinfectant-resistant, able to grow at low organic matter concentrations, and able to grow under stagnant conditions. Infections have been traced to exposure to premise plumbing or aerosols generated in showers. A number of measures can lead to reduction in OPPP numbers in premise plumbing, including elevation of water heater temperatures.

Physical Measures to Reduce Exposure to Tap Water-Associated Nontuberculous Mycobacteria

Nontuberculous mycobacteria (NTM) that cause human disease can be isolated from household tap water. Easy-to-use physical methods to reduce NTM from this potential source of exposure are needed. Filters and UV disinfection have been evaluated for their ability to reduce numbers of waterborne non-NTM organisms from drinking water, but their efficacy in reducing NTM counts are not well-established. Thus, five commercially available disinfection methods were evaluated for their potential as practical, efficient, and low-cost methods to reduce NTM from tap water. First, suspensions of tap water–adapted Mycobacterium smegmatis were passed through either a point-of-use, disposable, 7-day or 14-day Pall-Aquasafe filter. The 7-day filter prevented passage of M. smegmatis in effluent water for 13 days, and the 14-day filter prevented the passage of M. smegmatis for 25 days. Second, a granular activated carbon filter system failed to significantly reduce Mycobacterium abscessus and Mycobacterium avium numbers. Third, suspensions of tap water–adapted M. abscessus, M. avium, and M. chimaera (“MycoCocktail”) were passed through the “LifeStraw GO” hollow-fiber, two-stage membrane filtration system. LifeStraw GO prevented passage of the MycoCocktail suspension for the entire 68-day evaluation period. Finally, two different water bottle UV sterilization systems, “Mountop” and “SteriPEN,” were evaluated for their capacity to reduce NTM numbers from tap water. Specifically, MycoCocktail suspensions were dispensed into Mountop and SteriPEN water bottles and UV treated as per the manufacturer instructions once daily for 7 days, followed by a once weekly treatment for up to 56 days. After 4 days of daily UV treatment, both systems achieved a >4 log reduction in MycoCocktail CFU. After the 56-day evaluation period, suspension and biofilm-associated CFU were measured, and a >4 log reduction in CFU was maintained in both systems. Taken together, physical disinfection methods significantly reduced NTM numbers from tap water and may be easy-to-use, accessible applications to reduce environmental NTM exposures from drinking water.

Disinfection and cleaning of heater-cooler units: suspension- and biofilm-killing

BACKGROUND

Non-tuberculous mycobacteria (NTM) infections in cardiac surgery patients, caused by Mycobacterium chimaera or Mycobacterium abscessus, have been traced to NTM-aerosols produced by heater-cooler units of cardiopulmonary bypass equipment.

AIM

To develop a protocol to disinfect the water reservoir(s) of heater-coolers to reduce NTM numbers and thereby prevent potential NTM aerosolization; and to devise an approach to disrupt surface biofilms of heater-coolers to reduce reinoculation of the heater-cooler reservoir(s) after disinfection.

METHODS

A laboratory-scale Centers for Disease Control and Prevention bioreactor and a heater-cooler were inoculated with M. chimaera or M. abscessus to measure the ability of different disinfection protocols to reduce NTM colony-forming units in water and biofilm samples and to delay the reappearance of NTM after disinfection.

FINDINGS

The combination of an enzyme detergent cleaning agent and Clorox® were equivalent to Clorox alone in reducing M. chimaera cfu in heater-cooler water reservoir samples. However, reappearance of those bacteria was delayed by 12 weeks by the combination of enzyme detergent cleaning agent and Clorox exposure compared to Clorox disinfection alone.

CONCLUSION

A combination of an enzyme detergent and Clorox was an effective disinfection treatment and significantly delayed the reappearance of M. chimaera in the heater-cooler reservoir.

Construction and Use of Transposon MycoTetOP 2 for Isolation of Conditional Mycobacteria Mutants

Mycobacteria are unique in many aspects of their biology. The development of genetic tools to identify genes critical for their growth by forward genetic analysis holds great promises to advance our understanding of their cellular, physiological and biochemical processes. Here we report the development of a novel transposon, MycoTetOP², to aid the identification of such genes by direct transposon mutagenesis. This mariner-based transposon contains nested anhydrotetracycline (ATc)-inducible promoters to drive transcription outward from both of its ends. In addition, it includes the Escherichia coli R6Kγ origin to facilitate the identification of insertion sites. MycoTetOP² was placed in a shuttle plasmid with a temperature-sensitive DNA replication origin in mycobacteria. This allows propagation of mycobacteria harboring the plasmid at a permissive temperature. The resulting population of cells can then be subjected to a temperature shift to select for transposon mutants. This transposon and its delivery system, once constructed, were tested in the fast-growing model Mycobacterium smegmatis and 13 mutants with ATc-dependent growth were isolated. The identification of the insertion sites in these mutants led to nine unique genetic loci with genes critical for essential processes in both M. smegmatis and Mycobacterium tuberculosis. These results demonstrate that MycoTetOP² and its delivery vector provide valuable tools for the studies of mycobacteria by forward genetics.

Mycobacterium avium in Community and Household Water, Suburban Philadelphia, Pennsylvania, USA, 2010-2012

Attention to environmental sources of Mycobacterium avium complex (MAC) infection is a vital component of disease prevention and control. We investigated MAC colonization of household plumbing in suburban Philadelphia, Pennsylvania, USA. We used variable-number tandem-repeat genotyping and whole-genome sequencing with core genome single-nucleotide variant analysis to compare M. avium from household plumbing biofilms with M. avium isolates from patient respiratory specimens. M. avium was recovered from 30 (81.1%) of 37 households, including 19 (90.5%) of 21 M. avium patient households. For 11 (52.4%) of 21 patients with M. avium disease, isolates recovered from their respiratory and household samples were of the same genotype. Within the same community, 18 (85.7%) of 21 M. avium respiratory isolates genotypically matched household plumbing isolates. Six predominant genotypes were recovered across multiple households and respiratory specimens. M. avium colonizing municipal water and household plumbing may be a substantial source of MAC pulmonary infection.

Iridium piano stool complexes with activity against S. aureus and MRSA: it is past time to truly think outside of the box

A new class of piano-stool iridium complexes with 1,2-diaminoethane ligands are shown to be effective and safe antimicrobials with activity against Staphylococcus aureus, including various isolates of methicillin-resistant strains (MRSA). Comparison to other piano stool complexes with activity against mycobacteria are made along with a discussion of structure-activity relationships. The structures of one the most active complexes with the ligand cis-1,2-diaminocyclohexane and one of the least active complexes with the ligand trans-1,2-diaminocyclohexane are compared and discussed with respect to their drastically different activities. In vitro toxicity studies for all of the complexes are described. In addition, a mouse study with one of the complexes, [(pentamethylcyclopentadienyl)(cis-1,2-diaminocyclohexane)(chloro)iridium]chloride, showed no ill effects on the mice at high doses.

Interference of manganese removal by biologically-mediated reductive release of manganese from MnOx(s) coated filtration media

Discontinuing application of pre-filter chlorine is a common water treatment plant practice to permit a bioactive filtration process for the removal of soluble Mn. However, soluble Mn desorption has sometimes been observed following cessation of chlorine addition, where filter effluent Mn concentration exceeds the influent Mn concentration. In this paper it is hypothesized that Mn-reducing bacteria present in a biofilm on the filter media may be a factor in this Mn-release phenomenon. The primary objective of this research was to assess the role of Mn-reducing microorganisms in the release of soluble Mn from MnO_x(s)-coated filter media following interruption of pre-filtration chlorination. Bench-scale filter column studies were inoculated with Shewanella oneidensis MR-1 to investigate the impacts of a known Mn-reducing bacterium on release of soluble Mn from MnO_x(s) coatings. In situ vial assays were developed to gain insight into the impacts of MnO_x(s) age on bioavailability to Mn-reducing microorganisms and a quantitative polymerase chain reaction (qPCR) method was developed to quantify gene copies of the mtrB gene, which is involved in Mn-reduction. Results demonstrated that microbially-mediated Mn release was possible above a threshold equivalent of 2 × 10² S. oneidensis MR-1 CFU per gram of MnO_x(s) coated media and that those organisms contributed to Mn desorption and release. Further, detectable mtrB gene copies were associated with observed Mn desorption. Lastly, MnO_x(s) age appeared to play a role in Mn reduction and subsequent release, where MnO_x(s) solids of greater age indicated lower bioavailability. These findings can help inform means of preventing soluble Mn release from drinking water treatment plant filters.

Aerosolization of Mycobacterium avium and Mycobacterium abscessus from a household ultrasonic humidifier

PURPOSE

To measure the aerosolization of Mycobacterium avium subspecies hominissuis and Mycobacterium abscessus subspecies abscessus from ultrasonic humidifiers.

METHODOLOGY

An ultrasonic humidifier was filled with sterile tap water and inoculated with water-acclimated cells of either the M. avium or M. abscessus strains to achieve a range of densities similar to those of mycobacteria found in drinking waters. During operation of the humidifier, aerosols were collected using an Andersen 6-Stage Cascade Sampler.

RESULTS

Cells of the M. avium and M. abscessus strains were readily aerosolized and recovered in particles (1-5 µm diameter); small enough to enter the furthest reaches of the human lung. Aerosolization of M. abscessus was significantly reduced in the presence of a normal drinking water bacterial flora. Significantly greater numbers of M. avium cells were aerosolized from high-density suspensions (1200 c.f.u. ml^-1), than from low-density (120 c.f.u. ml^-1) and very low-density (12 c.f.u. ml^-1) suspensions.

CONCLUSIONS

This report documents the potential for M. avium subspecies hominissuis and M. abscessus subspecies abscessus cells in drinking water to be aerosolized from one type of portable humidifier; an ultrasonic humidifier. Care should be taken in using an ultrasonic humidifier where an individual at risk for mycobacterial pulmonary disease could be exposed.

Challenges of NTM Drug Development

Discovery and development of antibiotics active against the environmental opportunistic non-tuberculous mycobacteria (NTM) have been retarded by innate antibiotic-resistance of NTM cells and methodological challenges in the laboratory. The basis for the innate resistance of NTM cells is its lipid rich outer membrane that results in hydrophobic cells and the outer membrane’s impermeability, and the residence of NTM cells in phagocytic cells, and the slow growth and dormancy of NTM. Laboratory challenges include: the choice of species and strains for screening and measurement of anti-NTM activity, the high frequency colony switching between antibiotic-susceptible and resistant variants, the preference of NTM to adhere to surfaces and form biofilms, and the aggregation of NTM cells. Understanding these challenges can guide and inform our approaches to discovery and development of antibiotics with activity against NTM.

Mycobacterium avium complex: Adherence as a way of life

Mycobacterium avium complex (MAC) organisms are waterborne, opportunistic pathogens whose source is natural waters and soils and proliferates and persists in premise plumbing, for example household and hospital plumbing. M. avium complex and other environmental mycobacteria grow slowly, not because their metabolism is slow, but because they synthesize long chain (C₆₀–C₈₀) fatty acids that make up its hydrophobic and impermeable outer membrane. There are costs and benefits to the presence of that lipid-rich outer membrane. One benefit is that cell-surface hydrophobicity drives M. avium complex cells to adhere to surfaces to reduce their interaction with charged ions in suspension; they are likely “biofilm pioneers”, adhering to a wide variety of surface materials. The result is that the slow-growing M. avium complex cells (1 gen/day at 37 °C) will not be washed out of any flowing system, whether a stream or plumbing in the built environment. Although the slow permeation of nutrients in M. avium complex organisms limits growth, they are also resistant to disinfectants, thus increasing their survival in water distribution systems, premise plumbing, and medical equipment. There are three components to the antimicrobial resistance of M. avium complex in biofilms: (1) innate resistance due to the hydrophobic, impermeable outer membrane, (2) residence in a matrix of extracellular polysaccharide, lipid, DNA, and protein that prevents access of antimicrobials to M. avium cells, and (3) an adaptive and transient increased resistance of biofilm-grown M. avium cells grown in biofilms. As expected M. avium in biofilms will display neutral, antagonistic, or beneficial interactions with other biofilm inhabitants. Methylobacterium spp., the common pink-pigmented, waterborne bacteria compete with M. avium for surface binding, suggested an approach to reducing M. avium biofilm formation and hence persistence in premise plumbing.

Branched Peptides: Acridine and Boronic Acid Derivatives as Antimicrobial Agents

The emergence of microbial resistance presents a challenge in the development of next generation therapeutics. Herein, we report the discovery of branched peptides decorated with acridine and boronic acid moieties with potent antimicrobial activity. The results revealed minimal inhibitory concentrations (MICs) as low as 1 μg/mL against Staphylococcus aureus, Candida albicans, and Escherichia coli. These peptides were nonhemolytic, and significantly inhibited growth of C. albicans in suspension and biofilm formation. Structure-activity relationship studies suggest the acridine functional group as a driving force for the potent inhibition observed against bacteria.

Current Epidemiologic Trends of the Nontuberculous Mycobacteria (NTM)

The nontuberculous mycobacteria (NTM) are waterborne opportunistic pathogens of humans. They are normal inhabitants of premise plumbing, found, for example, in household and hospital shower heads, water taps, aerators, and hot tubs. The hydrophobic NTM are readily aerosolized, and pulmonary infections and hypersensitivity pneumonitis have been traced to the presence of NTM in shower heads. Hypersensitivity pneumonitis in automotive workers was traced to the presence of NTM in metal recovery fluid used in grinding operations. Recently, NTM bacteremia in heart transplant patients has been traced to the presence of NTM in water reservoirs of instruments employed in operating rooms to heat and cool patient blood during periods of mechanical circulation. Although NTM are difficult to eradicate from premise plumbing as a consequence of their disinfectant-resistance and formation of biofilms, measures such as reduction of turbidity and reduction in carbon and nitrogen for growth and the installation of microbiological filters can reduce exposure of NTM to susceptible individuals.

Environmental Nontuberculous Mycobacteria in the Hawaiian Islands

Lung disease caused by nontuberculous mycobacteria (NTM) is an emerging infectious disease of global significance. Epidemiologic studies have shown the Hawaiian Islands have the highest prevalence of NTM lung infections in the United States. However, potential environmental reservoirs and species diversity have not been characterized. In this cross-sectional study, we describe molecular and phylogenetic comparisons of NTM isolated from 172 household plumbing biofilms and soil samples from 62 non-patient households and 15 respiratory specimens. Although non-uniform geographic sampling and availability of patient information were limitations, Mycobacterium chimaera was found to be the dominant species in both environmental and respiratory specimens. In contrast to previous studies from the continental U.S., no Mycobacterium avium was identified. Mycobacterium intracellulare was found only in respiratory specimens and a soil sample. We conclude that Hawai’i’s household water sources contain a unique composition of Mycobacterium avium complex (MAC), increasing our appreciation of NTM organisms of pulmonary importance in tropical environments.

In the U.S., the Hawaiian Islands have the highest number of nontuberculous mycobacterial (NTM) lung disease cases per capita. The tropical climate, geographical isolation of the islands, and aquifer water sources may have influence such prevalence. Previous studies suggest that NTM thrive in water biofilms and soil. To broaden our understanding of potential environmental reservoirs and species composition of NTM in the Hawaiian Islands, we sampled environmental sites and examined patient isolates. Our recovery and identification of Mycobacterium chimaera and several other clinically relevant NTM species and the absence of Mycobacterium avium in both the indigenous environment and clinical specimens underscore the need for further studies to define the environmental factors that drive NTM lung disease and species composition in high prevalence locations such as the Hawaiian Islands.

Talarolutins A-D: Meroterpenoids from an endophytic fungal isolate of Talaromyces minioluteus

Four meroterpenoids [talarolutins A-D] and one known compound [purpurquinone A] were characterized from an endophytic fungal isolate of Talaromyces minioluteus (G413), which was obtained from the leaves of the medicinal plant milk thistle [Silybum marianum (L.) Gaertn. (Asteraceae)]. The structures of talarolutins A-D were determined by the analysis of various NMR and MS techniques. The relative and absolute configuration of talarolutin A was determined by X-ray diffraction analysis. A combination of NOESY data and comparisons of ECD spectra were employed to assign the relative and absolute configuration of the other analogs. Talarolutins B-D were tested for cytotoxicity against human prostate carcinoma (PC-3) cell line, antimicrobial activity, and induction of quinone reductase; no notable bioactivity was observed in any assay.

Methylobacterium spp. as an indicator for the presence or absence of Mycobacterium spp

OBJECTIVE/BACKGROUND

A published survey of bacteria in showerhead biofilm samples revealed that Methylobacterium spp. and Mycobacterium spp. seldom coexisted in biofilms.

METHODS

To confirm that information, biofilm samples were collected from household plumbing of Mycobacterium avium patients and Methylobacterium spp. and M. avium numbers were measured by direct colony counts.

RESULTS

The results demonstrated that if Methylobacterium spp. were present, Mycobacterium spp. were absent, and the opposite.

CONCLUSION

The data demonstrate that microbial populations in biofilms can influence the presence or absence of opportunistic premise plumbing pathogens and, thereby, increase the range of strategies to reduce exposure to waterborne pathogens. Finally, by assessing for the visual presence of methylobacteria as pink pigmentation on showers and shower curtains, homeowners and managers of hospitals and other buildings can quickly determine whether a premise plumbing biofilm sample has mycobacteria with a high degree of assurance.

Epidemiology and Ecology of Opportunistic Premise Plumbing Pathogens: Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa

BACKGROUND

Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa are opportunistic premise plumbing pathogens (OPPPs) that persist and grow in household plumbing, habitats they share with humans. Infections caused by these OPPPs involve individuals with preexisting risk factors and frequently require hospitalization.

OBJECTIVES

The objectives of this report are to alert professionals of the impact of OPPPs, the fact that 30% of the population may be exposed to OPPPs, and the need to develop means to reduce OPPP exposure. We herein present a review of the epidemiology and ecology of these three bacterial OPPPs, specifically to identify common and unique features.

METHODS

A Water Research Foundation-sponsored workshop gathered experts from across the United States to review the characteristics of OPPPs, identify problems, and develop a list of research priorities to address critical knowledge gaps with respect to increasing OPPP-associated disease.

DISCUSSION

OPPPs share the common characteristics of disinfectant resistance and growth in biofilms in water distribution systems or premise plumbing. Thus, they share a number of habitats with humans (e.g., showers) that can lead to exposure and infection. The frequency of OPPP-infected individuals is rising and will likely continue to rise as the number of at-risk individuals is increasing. Improved reporting of OPPP disease and increased understanding of the genetic, physiologic, and structural characteristics governing the persistence and growth of OPPPs in drinking water distribution systems and premise plumbing is needed.

CONCLUSIONS

Because broadly effective community-level engineering interventions for the control of OPPPs have yet to be identified, and because the number of at-risk individuals will continue to rise, it is likely that OPPP-related infections will continue to increase. However, it is possible that individuals can take measures (e.g., raise hot water heater temperatures and filter water) to reduce home exposures.

Cytotoxic Homoisoflavones from the Bulbs of Bellevalia eigii

Eight new and 10 known compounds were isolated from an organic extract of the bulbs of Bellevalia eigii as part of a search for anticancer leads from native plants of Jordan. Of these, the series of 16 homoisoflavonoids (1-16) comprise the seven new analogues 7-O-methyl-3'-hydroxy-3,9-dihydropunctatin (3), 6-hydroxy-7-O-methyl-3,9-dihydropunctatin (6), 7,4'-di-O-methyl-3'-hydroxy-3,9-dihydropunctatin (9), 7-O-methylpunctatin (10), 7-O-methyl-3'-hydroxypunctatin (13), 5-hydroxy-7,8-dimethoxychroman-4-one (14), and 7-O-methyl-8-demethoxy-3-hydroxy-3,9-dihydropunctatin (15). The known ferulic acid-derived acrylamide (17) and the new methylthioacrylate bellegimycin (18) are also reported. The structures were elucidated using a set of spectroscopic and spectrometric techniques; the absolute configurations of compounds 1-9, 15, and 16 were determined using ECD spectroscopy, while a modified Mosher's ester method was used for compound 18. Optical rotation data for the known compounds 1, 2, and 8 are reported here for the first time. The cytotoxic activities of all compounds were evaluated using the MDA-MB-435 (melanoma) and HT-29 (colon) cancer cell lines. Compounds 4 and 9 were the most potent on the latter cell line, with IC50 values of 1.0 and 1.1 μM, respectively. Compounds 1-18 were assessed for antimicrobial activity using a collection of bacteria and fungi; compounds 4 and 12 showed promising activity against the bacterium Mycobacterium smegmatis with MIC values of 17 and 24 μg/mL, respectively.

Distribution System Water Quality Affects Responses of Opportunistic Pathogen Gene Markers in Household Water Heaters

Illustrative distribution system operation and management practices shaped the occurrence and persistence of Legionella spp., nontuberculous mycobacteria (NTM), Pseudomonas aeruginosa, and two amoebae host (Acanthamoeba spp., Vermamoeba vermiformis) gene markers in the effluent of standardized simulated household water heaters (SWHs). The interplay between disinfectant type (chlorine or chloramine), water age (2.3-5.7 days) and materials (polyvinyl chloride (PVC), cement or iron) in upstream simulated distribution systems (SDSs) profoundly influenced levels of pathogen gene markers in corresponding SWH bulk waters. For example, Legionella spp. were 3-4 log higher in SWHs receiving water from chloraminated vs chlorinated SDSs, because of disinfectant decay from nitrification. By contrast, SWHs fed with chlorinated PVC SDS water not only harbored the lowest levels of all pathogen markers, but effluent from the chlorinated SWHs were even lower than influent levels in several instances (e.g., 2 log less Legionella spp. and NTM for PVC and 3-5 log less P. aeruginosa for cement). However, pathogen gene marker influent levels correlated positively to effluent levels in the SWHs (P < 0.05). Likewise, microbial community structures were similar between SWHs and the corresponding SDS feed waters. This study highlights the importance and challenges of distribution system management/operation to help control opportunistic pathogens.

Relationship between Organic Carbon and Opportunistic Pathogens in Simulated Glass Water Heaters

Controlling organic carbon levels in municipal water has been hypothesized to limit downstream growth of bacteria and opportunistic pathogens in premise plumbing (OPPPs). Here, the relationships between influent organic carbon (0–15,000 µg ozonated fulvic acid /L) and the number of total bacteria [16S rRNA genes and heterotrophic plate counts (HPCs)] and a wide range of OPPPs (gene copy numbers of Acanthamoeba polyphaga, Vermamoeba vermiformis, Legionella pneumophila, and Mycobacterium avium) were examined in the bulk water of 120-mL simulated glass water heaters (SGWHs). The SGWHs were operated at 32–37 °C, which is representative of conditions encountered at the bottom of electric water heaters, with water changes of 80% three times per week to simulate low use. This design presented advantages of controlled and replicated (triplicate) conditions and avoided other potential limitations to OPPP growth in order to isolate the variable of organic carbon. Over seventeen months, strong correlations were observed between total organic carbon (TOC) and both 16S rRNA gene copy numbers and HPC counts (avg. R² > 0.89). Although M. avium gene copies were occasionally correlated with TOC (avg. R² = 0.82 to 0.97, for 2 out of 4 time points) and over a limited TOC range (0–1000 µg/L), no other correlations were identified between other OPPPs and added TOC. These results suggest that reducing organic carbon in distributed water is not adequate as a sole strategy for controlling OPPPs, although it may have promise in conjunction with other approaches.

Opportunistic Premise Plumbing Pathogens: Increasingly Important Pathogens in Drinking Water

Opportunistic premise plumbing pathogens are responsible for a significant number of infections whose origin has been traced to drinking water. These opportunistic pathogens represent an emerging water borne disease problem with a major economic cost of at least $1 billion annually. The common features of this group of waterborne pathogens include: disinfectant-resistance, pipe surface adherence and biofilm formation, growth in amoebae, growth on low organic concentrations, and growth at low oxygen levels. Their emergence is due to the fact that conditions resulting from drinking water treatment select for them. As such, there is a need for novel approaches to reduce exposure to these pathogens. In addition to much-needed research, controls to reduce numbers and human exposure can be instituted independently by utilities and homeowners and hospital- and building-operators.

Common features of opportunistic premise plumbing pathogens

Recently it has been estimated that the annual cost of diseases caused by the waterborne pathogens Legionella pneumonia, Mycobacterium avium, and Pseudomonas aeruginosa is $500 million. For the period 2001-2012, the estimated cost of hospital admissions for nontuberculous mycobacterial pulmonary disease, the majority caused by M. avium, was almost $1 billion. These three waterborne opportunistic pathogens are normal inhabitants of drinking water--not contaminants--that share a number of key characteristics that predispose them to survival, persistence, and growth in drinking water distribution systems and premise plumbing. Herein, I list and describe these shared characteristics that include: disinfectant-resistance, biofilm-formation, growth in amoebae, growth at low organic carbon concentrations (oligotrophic), and growth under conditions of stagnation. This review is intended to increase awareness of OPPPs, identify emerging OPPPs, and challenge the drinking water industry to develop novel approaches toward their control.

Microaerobic growth and anaerobic survival of Mycobacterium avium, Mycobacterium intracellulare and Mycobacterium scrofulaceum

Representative strains of Mycobacterium avium, Mycobacterium intracellulare and Mycobacterium scrofulaceum (MAIS) grew at equal rates in laboratory medium at 21% (air) and 12% oxygen. Growth in 6% oxygen proceeded at a 1.4-1.8-fold lower rate. Colony formation was the same at 21% (air) and 6% oxygen. The MAIS strains survived rapid shifts from aerobic to anaerobic conditions as measured by two experimental approaches (Falkinham (1996) [1]). MAIS cells grown aerobically to log phase in broth were diluted, spread on agar medium, and incubated anaerobically for up to 20 days at 37°C. Although no colonies formed anaerobically, upon transfer to aerobic conditions, greater than 25% of the colony forming units (CFU) survived after 20 days of anaerobic incubation (Prince et al. (1989) [2]). MAIS cells grown in broth aerobically to log phase were sealed and vigorous agitation led to oxygen depletion (Wayne model). After 12 days anaerobic incubation, M. avium and M. scrofulaceum survival were high (>50%), while M. intracellulare survival was lower (22%). M. avium cells shifted to anaerobiosis in broth had increased levels of glycine dehydrogenase and isocitrate lyase. Growth of MAIS strains at low oxygen levels and their survival following a rapid shift to anaerobiosis is consistent with their presence in environments with fluctuating oxygen levels.

Biosynthetically Distinct Cytotoxic Polyketides from Setophoma terrestris

Sixteen polyketides belonging to diverse structural classes, including monomeric/dimeric tetrahydroxanthones and resorcylic acid lactones, were isolated from an organic extract of a fungal culture Setophoma terrestris (MSX45109) using bioactivity-directed fractionation as part of a search for anticancer leads from filamentous fungi. Of these, six were new: penicillixanthone B (5), blennolide H (6), 11-deoxy blennolide D (7), blennolide I (9), blennolide J (10), and pyrenomycin (16). The known compounds were: secalonic acid A (1), secalonic acid E (2), secalonic acid G (3), penicillixanthone A (4), paecilin B (8), aigialomycin A (11), hypothemycin (12), dihydrohypothemycin (13), pyrenochaetic acid C (14), and nidulalin B (15). The structures were elucidated using a set of spectroscopic and spectrometric techniques; the absolute configurations of compounds 1-10 were determined using ECD spectroscopy combined with time-dependent density functional theory (TDDFT) calculations, while a modified Mosher's ester method was used for compound 16. The cytotoxic activities of compounds (1-15) were evaluated using the MDA-MB-435 (melanoma) and SW-620 (colon) cancer cell lines. Compounds 1, 4, and 12 were the most potent with IC50 values ranging from 0.16 to 2.14 μM. When tested against a panel of bacteria and fungi, compounds 3 and 5 showed promising activity against the Gram-positive bacterium Micrococcus luteus with MIC values of 5 and 15 μg/mL, respectively.

Effect of drinking water treatment process parameters on biological removal of manganese from surface water

Soluble manganese (Mn) presents a significant treatment challenge to many water utilities, causing aesthetic and operational concerns. While application of free chlorine to oxidize Mn prior to filtration can be effective, this is not feasible for surface water treatment plants using ozonation followed by biofiltration because it inhibits biological removal of organics. Manganese-oxidizing bacteria (MOB) readily oxidize Mn in groundwater treatment applications, which normally involve pH > 7.0. The purpose of this study was to evaluate the potential for biological Mn removal at the lower pH conditions (6.2-6.3) often employed in enhanced coagulation to optimize organics removal. Four laboratory-scale biofilters were operated over a pH range of 6.3-7.3. The biofilters were able to oxidize Mn at a pH as low as pH 6.3 with greater than 98% Mn removal. Removal of simulated organic ozonation by-products was also greater than 90% in all columns. Stress studies indicated that well-acclimated MOB can withstand variations in Mn concentration (e.g., 0.1-0.2 mg/L), hydraulic loading rate (e.g., 2-4 gpm/ft(2); 1.36 × 10(-3)-2.72 × 10(-3) m/s), and temperature (e.g., 7-22 °C) typically found at surface water treatment plants at least for relatively short (1-2 days) periods of time.

Environmental sources of nontuberculous mycobacteria

Nontuberculous mycobacteria (NTM) include over 150 species. The source for human infection is the environment. NTM are normal inhabitants of soil and drinking water. NTM grow and persist in many buildings. They are not contaminants of drinking water, but members of the natural drinking water microbial population. Infection occurs because humans share the same habitats. Because the ecology, antibiotic susceptibility, and virulence of individual species differs, identifying NTM isolates to species is important. Treatment requires multiple antibiotics. NTM patients are innately sensitive to NTM infection, resulting in reinfection. Knowledge of the sources of NTM can reduce exposure to environmental NTM.

A surface with a biomimetic micropattern reduces colonization of Mycobacterium abscessus

Nontuberculous mycobacteria (NTM) are ubiquitous organisms found in soil, water, and biofilms. Engineered surface topography has been proposed as a method to reduce microbial biofilm formation. The Sharklet(®) micropattern silicone surface has been shown to reduce biofilm formation of pyogenic bacteria. We hypothesized that this micropattern surface will also reduce colonization by Mycobacterium abscessus, a human pathogen. Smooth and micropattern silicone samples were incubated with 1 × 10(6) M. abscessus mL(-1) for 2 and 4 days. After processing to optimize recovery of adhered mycobacteria, there was a 75% and 50% reduction in the number of viable M. abscessus recovered from the micropattern surfaces compared to the smooth surfaces at 2 and 4 days after inoculation, respectively. Ziehl-Neelsen staining after measures to remove the adherent microorganisms revealed fewer residual M. abscessus on the micropattern samples as compared to smooth samples, validating the quantitative culture results. Microscopic observation of 2, 4, and 8 day M. abscessus cultures on micropattern samples showed that the organisms preferentially colonized within the channels between the rectangular features. In summary, a micropattern surface reduces the colonization of a pathogenic NTM. It remains to be seen whether this micropattern can reduce infections in humans.