This study investigated the potential pulmonary toxicity of polycarbonate (PC) emissions from fused filament fabrication (FFF) three-dimensional printing (3DP) via inhalation in Sprague Dawley rats. Previously, our results demonstrated no significant pulmonary effects following exposure to a 0.5 mg/m(3) PC. A new exposure apparatus was developed that exposed animals at a concentration of 2.5 mg/m(3). Sixty rats were randomized into control (filtered air) and exposure groups (n = 30/group). Each group was further divided into five subgroups (n = 6/subgroup) with exposure durations of 1, 4, 8, 15, or 30 days (4 hr/day, 4 days/week). Following a 24-hr post-exposure period, body weight was measured, and blood samples were collected for hematological and biochemical analysis. Bronchoalveolar lavage fluid (BALF) was obtained from the right lung for cytology. The left lung and head/nasal tissues were preserved for histopathological evaluation. Lung deposition was estimated using the Multiple-Path Particle Dosimetry model, electron microscopy, and enhanced darkfield microscopy. In addition, filter samples were collected to measure bisphenol A. Exposure resulted in an estimated deposition of 0.28 µg/day within the alveoli and small airways. Microscopy indicated limited evidence of macrophage uptake. No significant changes were observed in BALF cell counts, lactate dehydrogenase activity, or hematological parameters. BALF levels of tissue inhibitor of metalloproteinases-1 and protein were elevated in the 30-day exposure group, although histopathology revealed no exposure-related changes in the lungs. In conclusion, this study found no marked pulmonary inflammation or toxicity in rats exposed to 2.5 mg/m(3) of PC 3D printing emissions for up to 30 days (4 hr/day).

Purpose: Pulmonary exposure to emissions from manipulating solid surface composite (SSC) materials has been associated with adverse health effects in humans and laboratory animals. Previous in vitro and in vivo investigations of SSC toxicity have been limited by particle delivery methods that do not fully recapitulate the workplace environment. This study sought to determine the acute SSC-induced pulmonary responses via whole-body inhalation exposure. Materials and Methods: A chamber for dust particle generation and an exposure system for characterization and animal exposures was constructed. The system successfully generated SSC at a concentration of 19.9 ± 1.5 mg/m(3). The aerosol count median aerodynamic diameter was 820 nm. First, C57BL/6 mice were exposed to SSC particles for 4 h (n = 6) or filtered air control followed by euthanasia either immediately or 24 h post-exposure. Lungs were analyzed for aluminum (Al) content using inductively coupled plasma atomic emission spectroscopy (ICP-AES) which measured a lung deposition of 19.13 ± 5.03 µg/g elemental Al, or approximately 64 µg/g SSC dust. Second, a group of mice (n = 9) was exposed to SSC particles at 20 mg/m(3) for 4 days, 4 h/day to assess the acute and sub-chronic pulmonary effects of SSC inhalation. Animals were euthanized at 1- and 56-days post-exposure. Results: Total estimated pulmonary deposition for these animals was 49.2 µg SSC dust/animal. No histopathologic changes were observed at any post-exposure time point; however, BALF total protein was increased at 1-day post-exposure. Conclusions: We conclude that exposure to dust from cutting SSC at this dose and post-exposure durations induces mild, transient inflammation.

Clinical isolates of the respiratory pathogen Bordetella pertussis in the United States have become predominantly deficient for the acellular vaccine immunogen pertactin through various independent mutations. Here, we report the complete genome sequences for four B. pertussis isolates that harbor novel deletions responsible for pertactin deficiency.

During 2010 and 2012, California and Vermont, respectively, experienced statewide epidemics of pertussis with differences seen in the demographic affected, case clinical presentation, and molecular epidemiology of the circulating strains. To overcome limitations of the current molecular typing methods for pertussis, we utilized whole-genome sequencing to gain a broader understanding of how current circulating strains are causing large epidemics. Through the use of combined next-generation sequencing technologies, this study compared de novo, single-contig genome assemblies from 31 out of 33 Bordetella pertussis isolates collected during two separate pertussis statewide epidemics and 2 resequenced vaccine strains. Final genome architecture assemblies were verified with whole-genome optical mapping. Sixteen distinct genome rearrangement profiles were observed in epidemic isolate genomes, all of which were distinct from the genome structures of the two resequenced vaccine strains. These rearrangements appear to be mediated by repetitive sequence elements, such as high-copy-number mobile genetic elements and rRNA operons. Additionally, novel and previously identified single nucleotide polymorphisms were detected in 10 virulence-related genes in the epidemic isolates. Whole-genome variation analysis identified state-specific variants, and coding regions bearing nonsynonymous mutations were classified into functional annotated orthologous groups. Comprehensive studies on whole genomes are needed to understand the resurgence of pertussis and develop novel tools to better characterize the molecular epidemiology of evolving B. pertussis populations. IMPORTANCE Pertussis, or whooping cough, is the most poorly controlled vaccine-preventable bacterial disease in the United States, which has experienced a resurgence for more than a decade. Once viewed as a monomorphic pathogen, B. pertussis strains circulating during epidemics exhibit diversity visible on a genome structural level, previously undetectable by traditional sequence analysis using short-read technologies. For the first time, we combine short- and long-read sequencing platforms with restriction optical mapping for single-contig, de novo assembly of 31 isolates to investigate two geographically and temporally independent U.S. pertussis epidemics. These complete genomes reshape our understanding of B. pertussis evolution and strengthen molecular epidemiology toward one day understanding the resurgence of pertussis.