Clinical Persistence of Chlamydia trachomatis Sexually Transmitted Strains Involves Novel Mutations in the Functional αββα Tetramer of the Tryptophan Synthase Operon.

Clinical persistence of Chlamydia trachomatis (Ct) sexually transmitted infections (STIs) is a major public health concern. In vitro persistence is known to develop through interferon gamma (IFN-γ) induction of indoleamine 2,3-dioxygenase (IDO), which catabolizes tryptophan, an essential amino acid for Ct replication. The organism can recover from persistence by synthesizing tryptophan from indole, a substrate for the enzyme tryptophan synthase. The majority of Ct strains, except for reference strain B/TW-5/OT, contain an operon comprised of α and β subunits that encode TrpA and TrpB, respectively, and form a functional αββα tetramer. However, trpA mutations in ocular Ct strains, which are responsible for the blinding eye disease known as trachoma, abrogate tryptophan synthesis from indole. We examined serial urogenital samples from a woman who had recurrent Ct infections over 4 years despite antibiotic treatment. The Ct isolates from each infection episode were genome sequenced and analyzed for phenotypic, structural, and functional characteristics. All isolates contained identical mutations in trpA and developed aberrant bodies within intracellular inclusions, visualized by transmission electron microscopy, even when supplemented with indole following IFN-γ treatment. Each isolate displayed an altered αββα structure, could not synthesize tryptophan from indole, and had significantly lower trpBA expression but higher intracellular tryptophan levels compared with those of reference Ct strain F/IC-Cal3. Our data indicate that emergent mutations in the tryptophan operon, which were previously thought to be restricted only to ocular Ct strains, likely resulted in in vivo persistence in the described patient and represents a novel host-pathogen adaptive strategy for survival.IMPORTANCE Chlamydia trachomatis (Ct) is the most common sexually transmitted bacterium with more than 131 million cases occurring annually worldwide. Ct infections are often asymptomatic, persisting for many years despite treatment. In vitro recovery from persistence occurs when indole is utilized by the organism's tryptophan synthase to synthesize tryptophan, an essential amino acid for replication. Ocular but not urogenital Ct strains contain mutations in the synthase that abrogate tryptophan synthesis. Here, we discovered that the genomes of serial isolates from a woman with recurrent, treated Ct STIs over many years were identical with a novel synthase mutation. This likely allowed long-term in vivo persistence where active infection resumed only when tryptophan became available. Our findings indicate an emerging adaptive host-pathogen evolutionary strategy for survival in the urogenital tract that will prompt the field to further explore chlamydial persistence, evaluate the genetics of mutant Ct strains and fitness within the host, and their implications for disease pathogenesis

Environmentally-Friendly RF Plasma Treatment of Thai Silk Fabrics with Chitosan for Durable Antibacterial Property

A 13.56 MHz RF plasma discharge was successfully utilized to activate and coat Thai silk fabrics with chitosan for durable antibacterial property. Uncolored and untreated Thai silk fabrics were activated in Ar plasma for 5 minutes with an optimized RF power of 120 W under Ar pressure of 0.8 Torr. After plasma activation, specimens were submerged and stirred in a 1% (w/v) chitosan solution. FTIR analysis confirmed the presence of chitosan on the silk fabrics. From SEM analysis, chitosan was observed to coat silk fibers almost everywhere. RF plasma treated fabrics were able to absorb the chitosan solution substantially faster than those without the treatment. Another benefit of increased hydrophilicity is the ability of the treated fabrics to allow human perspiration to flow through more effectively, providing additional comfort when worn in tropical-zone countries. Antibacterial properties against E. coli and S. aureus reduced with increasing washing cycles dropping to approximately 95% after 5 rounds of washing. Extrapolation of linear trend lines revealed that for the case of E. coli, it will take approximately 16 washing cycles to reduce the antibacterial ability to 90%. For the case of S. aureus, it will take approximately 10 washing cycles to reduce the antibacterial ability to 90%. Fabrics without RF plasma treatment prior to chitosan solution submersion will have their antibacterial ability for E. coli and S. aureus reduced to 90% after only about 5 washing cycles. Thus, RF plasma treatment can effectively induce chitosan to provide a strong and durable coating for Thai silk fabrics, thus, offering a new, very environmentally-friendly coating technique for Thai silk with chitosan for potential use in the textile industry

Microbial and Small Eukaryotes Associated With Reefs in the Upper Gulf of Thailand

Reef sites of Ko Samae San (S), Khao Ma Cho (K) and Ko Tao Mo (T) in the upper Gulf of Thailand have abundant corals and represent a hotspot of marine biodiversity. Coral reefs serve as major networks of food and energy, where bacteria, microbial eukaryotes (fungi) and small eukaryotes play significant roles as primary producers that convert inorganic compounds to organic compounds, degraders of toxic substances, and recyclers. These functions sustain food and energy supplies. Advances in metagenomics and next-generation sequencing can provide knowledge of diversity without limitations imposed by media and other conditions associated with laboratory cultures. Scientists have researched bacterial diversity of coral sites; however, a database for fungi and small eukaryotes from Thailand’s sites with abundant corals is lacking. The present study combined fungal ribosomal intergenic spacer analysis (F-RISA) and 18S rRNA gene sequencing to unveil the first culture-independent microbial and small eukaryotes from these sites at two times and across four species of coral (Porites lutea, Platygyra sinensis, Acropora humilis, and Acropora millepora), seawater and sediment. Results showed that the small eukaryotic communities on corals were distinct from communities in the surrounding seawater and sediment. The communities were relatively similar at the three sites and during the two periods of time. Pearson’s correlations indicated the community diversity were associated with water quality (e.g., dissolved oxygen concentrations and density of water)

Ocular Microbiota of Severe Meibomian Gland Dysfunction (Chronic Dry Eyes) after Intense Pulsed Light (IPL)

Ocular IPL therapy has recently been widely used for MGD, especially for patients not showing improvement with traditional therapies (warm compresses and lid scrubs) to clean debris and reduce bacterial overgrowth. Insights on the ocular microbiome and quantitative microbiome in MGD after a course of IPL could provide useful data on bacterial community monitoring and associated mechanisms linked with IPL. Ocular swabs were obtained from a severe MGD patient and age-sex matched healthy for metagenomics, followed by 16S rRNA gene sequencing and qPCR. Of 10 samples, including left and right eyes (el, er) of severe MGD females before (Db) and after 2-4 IPLs (Da2, Da3, and Da4) and the matched non-MGD females (H), both of ~40 years Using 16S rRNA gene sequencing as microbiota and combined 16S rRNA gene qPCR as quantitative microbiota revealed significant disperse in the microbiome structures of Db compared with Da and H (HOMOVA, p<0.001). Bacterial Propionibacterium acnes and unclassified taxa in the family Propionibacteriaceae and order Actinomycetales represented the core Db microbiota and were reduced after 2-4 IPLs in Da, making the Da microbiome and clinical (mucocutaneous junction, corneal, and conjunctival fluorescein score) closer to H (NMDS with Pearson’s correlation, p<0.05). The recovery of the Da microbiome also allowed Da metabolic potentials to be closer to H. Our findings first demonstrated the ocular microbiome dysbiosis in severe MGD, dispersed from Da and H, in Thai subjects, correlated with bacterial quantity and clinical MGD, including the mucocutaneous junction process. The results additionally provided taxa representing Db vs. Da and H and preliminarily underlie the idea that IPL could improve dysbiosis in the MGD microbiome. Doi: 10.28991/ESJ-2023-07-05-015 Full Text: PD

Potential impact of ocular intense pulsed light on eyelash microbiome in severe meibomian gland dysfunction: report of 2 cases

Meibomian gland dysfunction (MGD) is a prevalent worldwide eye disorder that causes eye irritation, inflammation, chronic dryness, and blurred vision. Traditional therapies offer temporary improvement, but their efficacy varies in severe MGD cases. Ocular intense pulsed light (IPL) has emerged as a novel therapy, providing long-term symptom relief and shorter treatment durations compared to traditional approaches. However, the impact of IPL on the bacterial community within the eyes remains limited. To address this, we conducted a preliminary study using metagenomics and next-generation sequencing. We compared the bacterial eyelash communities of Thai females with severe MGD before and after 2-4 IPL treatments, and against a group of healthy females. Our findings revealed higher bacterial diversity in healthy individuals compared to severe MGD cases. IPL treatments increased diversity in the MGD group, making their core bacterial community more similar to that of healthy subjects. Notably, the presence of Koribacteraceae in severe MGD and Bifidobacterium in healthy individuals and post-IPL-treated MGD exemplified this shift. Clustering analysis showed a closer relationship between post-IPL-treated MGH and healthy subjects, while the pre-IPL treatment group formed a separate branch. These results suggest that IPL treatment can reshape the eyelash microbiome in MGD cases, but further research is needed to understand the implications and the microbiome’s role in MGD pathogenesis and treatment response

Effect of tarcolimus on skin microbiome in atopic dermatitis

No abstract available

Spatial and Seasonal Variability of Reef Bacterial Communities in the Upper Gulf of Thailand

Reefs at Ko Samae San (S), Khao Ma Cho (K), and Ko Tao Mo (T), in the Gulf of Thailand (GoT) represent a biodiversity hotspot, and bacteria play significant roles in maintaining the health of these coral reefs and their biogeochemical cycles. Therefore, this study analyzed bacterial communities (microbiota) from healthy corals and nearby seawater and sediment, using B-RISA and 16S rRNA gene sequencing. Sampling was done in one dry and one wet season to provide an initial assessment of variation with environmental conditions. The most prevalent coral species were Porites lutea, Platygyra sinensis, Acropora humilis, and Acropora millepora. The B-RISA and the sequencing results were correlated, which increased confidence the results. The microbiota varied among corals, seawater, and sediment and between the wet and dry seasons. Percentages of bacteria with known functions varied among sample types and seasons, and their relative abundances supported previously reported essential functions, such as prevention of disease (e.g., Pseudoalteromonas, Psychrobacter, and Cobetia were more abundant on corals in the dry season). Pearson's correlations and multiple factor regressions identified dissolved oxygen (DO), temperature, salinity, and density as significant influences on the microbiota. The equations estimated the relative abundance of a community comprising 147 bacterial genera, as well as the relative abundance of Pseudomonas, Clostridium, Verrucomicrobium, and Epulopiscium (R2 ≥ 0.721). These results represent the first descriptions of microbiota from corals, and surrounding seawater and sediments in the upper GoT

Mud crab susceptibility to disease from white spot syndrome virus is species-dependent

<p>Abstract</p> <p>Background</p> <p>Based on a report for one species (<it>Scylla serrata</it>), it is widely believed that mud crabs are relatively resistant to disease caused by white spot syndrome virus (WSSV). We tested this hypothesis by determining the degree of susceptibility in two species of mud crabs, <it>Scylla olivacea </it>and <it>Scylla paramamosain</it>, both of which were identified by mitochondrial 16 S ribosomal gene analysis. We compared single-dose and serial-dose WSSV challenges on <it>S. olivacea </it>and <it>S. paramamosain</it>.</p> <p>Findings</p> <p>In a preliminary test using <it>S. olivacea </it>alone, a dose of 1 × 10⁶WSSV copies/g gave 100% mortality within 7 days. In a subsequent test, 17 <it>S. olivacea </it>and 13 <it>S. paramamosain </it>were divided into test and control groups for challenge with WSSV at 5 incremental, biweekly doses starting from 1 × 10⁴and ending at 5 × 10⁶copies/g. For 11 <it>S. olivacea </it>challenged, 3 specimens died at doses between 1 × 10⁵and 5 × 10⁵copies/g and none died for 2 weeks after the subsequent dose (1 × 10⁶copies/g) that was lethal within 7 days in the preliminary test. However, after the final challenge on day 56 (5 × 10⁶copies/g), the remaining 7 of 11 <it>S. olivacea </it>(63.64%) died within 2 weeks. There was no mortality in the buffer-injected control crabs. For 9 <it>S. paramamosain </it>challenged in the same way, 5 (55.56%) died after challenge doses between 1 × 10⁴and 5 × 10⁵copies/g, and none died for 2 weeks after the challenge dose of 1 × 10⁶copies/g. After the final challenge (5 × 10⁶copies/g) on day 56, no <it>S. paramamosain </it>died during 2 weeks after the challenge, and 2 of 9 WSSV-infected <it>S. paramamosain </it>(22.22%) remained alive together with the control crabs until the end of the test on day 106. Viral loads in these survivors were low when compared to those in the moribund crabs.</p> <p>Conclusions</p> <p><it>S. olivacea </it>and <it>S. paramamosain </it>show wide variation in response to challenge with WSSV. <it>S. olivacea </it>and <it>S. paramamosain </it>are susceptible to white spot disease, and <it>S. olivacea </it>is more susceptible than <it>S. paramamosain</it>. Based on our single-challenge and serial challenge results, and on previous published work showing that <it>S. serrata </it>is relatively unaffected by WSSV infection, we propose that susceptibility to white spot disease in the genus <it>Scylla </it>is species-dependent and may also be dose-history dependent. In practical terms for shrimp farmers, it means that <it>S. olivacea </it>and <it>S. paramamosain </it>may pose less threat as WSSV carriers than <it>S. serrata</it>. For crab farmers, our results suggest that rearing of <it>S. serrata </it>would be a better choice than <it>S. paramamosain </it>or <it>S. olivacea </it>in terms of avoiding losses from seasonal outbreaks of white spot disease.</p

Discovering and Differentiating New and Emerging Clonal Populations of Chlamydia trachomatis with a Novel Shotgun Cell Culture Harvest Assay

This assay, coupled with ompA and 16S rRNA sequencing, characterized clonal populations of C. trachomatis