Biology subjects

Aydin, M.

Publications and source records attributed to Aydin, M..

4 recordsLinked to original sources

bioRxiv2025

Chlamydia muridarum Infection Impacts Murine Models of Intestinal Inflammation and Cancer

Chlamydia muridarum (Cm) has reemerged as a prevalent infectious agent in research mouse colonies. Despite its prevalence and ability to persistently colonize the murine gastrointestinal tract, few studies have evaluated the potential impact of Cm on experimental models of gastrointestinal disease. Studies were conducted to evaluate the impact of Cm on the Citrobacter rodentium (Cr), Trichuris muris (Tm) and Il10-/- mouse models of intestinal inflammation, as well as on tumorigenesis in the ApcMin/+ mouse following administration of DSS. Naive C57BL/6J (B6), B6.129P2-Il10tm1Cgn/J (Il10-/-) and C57BL/6J-ApcMin/J (ApcMin/+) mice were infected with Cm by cohousing with chronic Cm-shedding BALB/cJ mice for 2 weeks; controls were cohoused with Cm-free mice. After cohousing, B6 mice (n=8 Cm-infected and free) were infected with Citrobacter rodentium (Cr; 109 CFU orally) or Trichuris muris (Tm; 200 ova orally). Il10-/- mice (n=8/group with and without Helicobacter hepaticus [108 CFU/mouse] and with and without Cm) and ApcMin/+ mice (n=8/group) received 2% DSS for 7 days in drinking water after cohousing. Mice were sacrificed 14-days post-Cr infection, 18-days post-Tm infection, 70-days after cessation of cohousing with Il10-/- mice, and 28-days post-DSS administration to ApcMin/+ mice. The severity of the cecal and colonic lesions were evaluated and graded using a tiered, semi-quantitative scoring system. Cm infection attenuated colitis associated with Cr (p=0.03), had no effect on Tm associated pathology (p=0.22), worsened colitis in Il10-/- mice in the absence of H. hepaticus (p=0.007), and reduced chemically induced colonic tumorigenesis in ApcMin/+ mice (p=0.004). Thus, Cm colonization differentially impacts several models of intestinal inflammation and tumorigenesis, and the presence of this bacterium in mouse colonies should be considered as a variable in these experimental readouts.

microbiology↗

bioRxiv2024

Assessment of Antimicrobial Therapy in Eradicating Chlamydia muridarum in Research Mice: Immune Status and its Impact on Outcomes

Chlamydia muridarum (Cm) is a moderately prevalent, gram-negative, intracellular bacterium that affects laboratory mice, causing subclinical to severe disease, depending on the hosts immune status. The effectiveness of various antibiotic regimens aimed at eradicating Cm in both immunodeficient and immunocompetent laboratory mice was evaluated. NSG mice were cohoused with Cm-shedding BALB/cJ mice for 14 days to simulate natural exposure. Four groups of 8 infected NSG mice were treated for 7 days with either 0.08% sulfamethoxazole and 0.016% trimethoprim (TMS) in water, 0.0625% doxycycline in feed, 0.124%/0.025% TMS in feed, or 0.12% amoxicillin in feed. A control group was provided standard water and feed. The impact of treatment on gastrointestinal microbiota (GM) was performed using next-generation shotgun sequencing on the last day of treatment. TMS and Amoxicillin had negligible effects on GM, while doxycycline had the largest effect. All antibiotic treated NSG mice exhibited clinical disease, including dehydration, hunched posture, >20% weight loss, and dyspnea, leading to euthanasia 21-40 days post-treatment (32.6 {+/-} 4.2 days; mean {+/-} SD). Untreated controls were euthanized 14-33 days post-exposure (23.75 {+/-} 5.9 days). All mice were fecal PCR positive for Cm at euthanasia. Histological evaluation revealed multifocal histiocytic and neutrophilic bronchointerstitial pneumonia and/or bronchiolitis featuring prominent intralesional chlamydial inclusion bodies in all mice. Subsequently, groups of 8 C57BL/6J, BALB/cJ, NOD.SCID, and NSG mice infected with Cm were treated with 0.124%/0.025% TMS in feed for 7 (BALB/cJ and C57BL/6J) or 21 days (NSG and NOD.SCID). All immunocompetent and NOD.SCID mice were negative for Cm by PCR 14 days post-treatment, remained clinically normal and had no evidence of Cm infection at necropsy, all NSG mice remained Cm positive and were euthanized. While these findings highlight the difficulties in eradicating Cm from highly immunodeficient mice, eradication of Cm from immunocompetent or moderately immunocompromised mice with antibiotics is feasible.

pharmacology and toxicology↗

bioRxiv2024

Examining Intercage Transmission of Chlamydia muridarum: Impact of Barrier Husbandry and Cage Sanitization

Chlamydia muridarum (Cm) has reemerged as a prevalent bacterial contaminant of academic research mouse colonies. A study was conducted to assess the effectiveness of husbandry and cage sanitization methods in preventing intercage transmission of Cm. To assess intercage transmission during cage change, a cage housing 2 Cm-free Swiss Webster (Tac:SW; SW) sentinel mice was placed randomly on each of 12 individually ventilated cage racks, housing cages with Cm-shedding mice, located in 1 of 2 animal holding rooms. Husbandry staff blinded to the study cages, changed all cages in the animal holding rooms weekly using microisolator cage technique. PCR testing performed 180 days post-placement confirmed all mice remained negative for Cm. To assess the effectiveness of cage sanitization to eliminate Cm, we investigated transmission of Cm to a naive Cm-free SW and NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mouse co-housed for 7 days (repeated weekly for 4 weeks) in cages assigned to 1 of 3 groups (n=10 pairs of mice/group). Cages that previously housed 2 Cm-shedding BALB/c mice were either washed in a tunnel washer (82.2{degrees}C [180{degrees}F] final rinse for an average of 16 seconds per run; n=10) with and without post-washing autoclaving (121{degrees}C for 20 minutes; n=10), or were untreated (bedding change only; n=10). Pre- and post-sanitization swabs of each cage were assayed for Cm by PCR. All pre-treatment swabs tested positive, while post-treatment swabs from all cages (excluding bedding change) tested negative. All SW and NSG mice, irrespective of group, remained negative for Cm as determined by PCR. These findings suggest that infectious Cm does not persist in untreated cages nor after mechanical washing with and without autoclaving. Collectively, these findings suggest that neither our husbandry protocols nor inadequate cage sanitization methods likely contributed to the observed prevalence of Cm in contemporary research mouse colonies.

microbiology↗

bioRxiv2020

Rapid Isothermal Amplification and Portable Detection System for SARS-CoV-2

The COVID-19 pandemic provides an urgent example where a gap exists between availability of state-of-the-art diagnostics and current needs. As assay details and primer sequences become widely known, many laboratories could perform diagnostic tests using methods such as RT-PCR or isothermal RT-LAMP amplification. A key advantage of RT-LAMP based approaches compared to RT-PCR is that RT-LAMP is known to be robust in detecting targets from unprocessed samples. In addition, RT-LAMP assays are performed at a constant temperature enabling speed, simplicity, and point-of-use testing. Here, we provide the details of an RT-LAMP isothermal assay for the detection of SARS-CoV-2 virus with performance comparable to currently approved tests using RT-PCR. We characterize the assay by introducing swabs in virus spiked synthetic nasal fluids, moving the swab to viral transport medium (VTM), and using a volume of that VTM for performing the amplification without an RNA extraction kit. The assay has a Limit-of-Detection (LOD) of 50 RNA copies/L in the VTM solution within 20 minutes, and LOD of 5000 RNA copies/L in the nasal solution. Additionally, we show the utility of this assay for real-time point-of-use testing by demonstrating detection of SARS-CoV-2 virus in less than 40 minutes using an additively manufactured cartridge and a smartphone-based reader. Finally, we explore the speed and cost advantages by comparing the required resources and workflows with RT-PCR. This work could accelerate the development and availability of SARS-CoV-2 diagnostics by proving alternatives to conventional laboratory benchtop tests. Significance StatementAn important limitation of the current assays for the detection of SARS-CoV-2 stem from their reliance on time- and labor-intensive and laboratory-based protocols for viral isolation, lysis, and removal of inhibiting materials. While RT-PCR remains the gold standard for performing clinical diagnostics to amplify the RNA sequences, there is an urgent need for alternative portable platforms that can provide rapid and accurate diagnosis, potentially at the point-of-use. Here, we present the details of an isothermal amplification-based detection of SARS-CoV-2, including the demonstration of a smartphone-based point-of-care device that can be used at the point of sample collection.

bioengineering↗