Biology subjects

Lipman, N. S.

Publications and source records attributed to Lipman, N. S..

12 recordsLinked to original sources

bioRxiv2026

Skin and Gut Microbiome Features Associated with Resistance to Corynebacterium bovis-Associated Disease in Nude Mice (Mus musculus)

Corynebacterium bovis is an important opportunistic pathogen of immunodeficient mice and the etiologic agent of Corynebacterium-associated hyperkeratosis (CAH). Although disease severity varies, specific vendor-derived microbiomes have been shown to protect against CAH. Preinoculation with nonpathogenic Corynebacterium amycolatum prior to C. bovis infection has been demonstrated to limit disease severity. To define community features associated with protection, axenic outbred athymic nude mice stocks (A, B, and C) were reassociated with donor microbiomes from four vendor sources (A1, A2, B, and C) and topically challenged with C. bovis. C. amycolatum was added to the A1 microbiome in a separate group. Skin (Stock A) and fecal (Stocks A, B, and C) microbiomes were evaluated at 21 days post-inoculation via shotgun metagenomic sequencing. The A2 microbiome, previously associated with resistance to clinical disease and minimal skin pathology, exhibited greater cutaneous microbial evenness after challenge and significantly lower relative abundance of C. bovis than all other microbiome groups. Addition of C. amycolatum to the A1 microbiome did not fully confer disease protection and relative abundance was low, suggesting that sustained colonization by this organism was insufficient to explain the protective phenotype seen with the A2 microbiome. C. kroppenstedtii was detected in all A2 skin samples and was absent from all other groups. Several anaerobic taxa, including Duncaniella dubosii, D. muris, Bacteroides caecimuris, and Muribaculum gordoncarteri, were uniquely detected or enriched in the A2-associated microbiome, whereas Mammaliicoccus lentus and Staphylococcus nepalensis were absent from A2 but present in all nonprotective groups. Gut alpha diversity did not differ significantly among microbiomes, although several taxa, including segmented filamentous bacteria, were enriched in A2 feces. These findings associate resistance to CAH with preservation of cutaneous community structure, suppression of C. bovis prominence, and distinct microbial taxa. The identified organisms represent candidates for future mechanistic studies of microbiome-mediated colonization resistance.

zoology↗

bioRxiv2026

Microbiome-Dependent Protection Against Corynebacterium bovis-Associated Hyperkeratosis in Nude Mice (Mus musculus)

Corynebacterium bovis, the cause of Corynebacterium-associated hyperkeratosis (CAH), is an important pathogen in immunocompromised mice that is difficult to eliminate and can confound research outcomes. We recently observed that CAH severity varies among outbred athymic nude mouse stocks, but the relative contributions of host genetics and the microbiome remain unclear. We hypothesized that disease course and severity vary based on host genetic stock and/or microbiome composition. Three nude mouse stocks were rederived into the axenic state and either monoinfected with a pathogenic C. bovis isolate (104; CFU) or given sterile media (n=6/group). Axenic mice were also reassociated with their source microbiome or microbiomes from three other stocks with known differences in CAH severity, then inoculated with C. bovis (n=6) or sterile media (n=2). In a separate experiment, one axenic stock was used to assess the role of C. amycolatum via monoinfection, monoinfection followed by C. bovis challenge, or addition to a nonprotective microbiome followed by C. bovis challenge. Mice were monitored daily for 21 days and scored for skin lesions (0-5). C. bovis monoinfected mice developed disease comparable in severity and timing to conventionally raised controls. Notably, reassociation with Vendor A2s microbiome prevented clinical lesions and reduced histopathologic changes across all stocks. While C. amycolatum as a monoinfection did not cause disease nor reduce disease severity following C. bovis challenge, it delayed the onset and lowered peak scores when added to a non-protective microbiome. These findings demonstrate that C. bovis can cause CAH as a monoinfection, that both host genetics and microbiome composition influence disease progression, and, together with prior work, support its role as the etiologic agent consistent with Kochs postulates. Identifying protective microbiome constituents may inform strategies to reduce disease burden in susceptible mice.

microbiology↗

bioRxiv2025

A novel strategy to mitigate Corynebacterium bovis-associated hyperkeratosis (CAH) in athymic nude mice

Nude mice were inoculated with a non-pathogenic Cb isolate (NPI) or Corynebacterium amycolatum (Ca) to assess whether either could prevent skin lesions following inoculation with a pathogenic Cb isolate (PI). Crl:NU(NCr)-Foxn1nu mice (n=6/group) were randomized into 6 groups: NPI (108 CFU); Ca (108 CFU); NPI or Ca followed 2 weeks later by PI (104 CFU); and negative and positive controls receiving sterile media or the PI (104 CFU), respectively. Colonization was assessed biweekly using isolate-specific PCR assays. Skin lesions were scored 0 - 5 daily for 4 or 6 weeks at which point skin biopsies were collected, evaluated and scored. No mice inoculated with the NPI and subsequently infected with the PI developed clinical signs nor was a significant amount of the PI detected by PCR. Mice inoculated with Ca before the PI developed milder, delayed skin lesions reaching a significantly lower mean peak clinical score (MPCS; 1.2 +/- 0.4) as compared to the positive control (MPCS 2.5 +/- 0.5). The Ca inoculated mice with and without PI had similar total histopathology scores, both of which were significantly higher than the mice inoculated with the NPI followed by the PI. These results led to evaluation of a practical exposure strategy in which nude mice (n=6/group) were housed on NPI-seeded bedding (SB) for 3 or 7 days prior to PI administration; mice housed on Cb-free bedding served as controls. Only 1 of 12 mice housed on SB receiving the PI developed CAH (peak score of 4), whereas all unvaccinated mice receiving the PI developed CAH (MPCS 2.83 +/- 0.69). The PI was not detected in the SB + PI groups until 21 days post-infection with the PI. There was no significant difference in total histopathology scores across groups, but the histopathology scores were lower in mice receiving the SB.

microbiology↗

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

Assessing the Biosecurity Risk of Footwear as a Fomite for Transmission of Adventitious Infectious Agents to Mice

The soles of staff shoes accessing vivaria can become contaminated on urban streets, potentially serving as a source of fomite-mediated transmission of adventitious agents to laboratory rodents. While shoe covers may mitigate this risk, donning them can lead to hand contamination. Staff accessing our vivaria use motor-driven shoe cleaners hundreds of times daily to remove and collect particulates via a vacuum collection system from the top, sole, and sides of shoes instead of shoe covers. Shoe cleaner debris (SCD) and contact media (CM) exposed to SCD from shoe cleaners in 5 vivaria were assessed by PCR for 84 adventitious agents. SCD and CM samples tested positive for 33 and 37 agents, respectively, and a combined 39 agents total. To assess SCD infectivity, NSG and Swiss outbred mice were housed for 7 days in direct contact with SCD and oronasally inoculated with a suspension created from SCD collected from each of the 5 vivaria. Mice were tested by PCR and serology 3-, 7-, 14- and 63-days post-inoculation. All mice remained healthy until the studys end and tested negative for all agents found in SCD/CM except murine astrovirus 1, Staphyloccocus xylosus and Candidatus Savagella, agents known to be enzootic in the experimental mouse source colony. In a follow-up study, the soles of 27 staff street shoes were directly sampled using CM. Half of CM was used for PCR, while the other half was added as bedding material to a cage containing NSG and Swiss outbred mice. While CM tested positive for 11 agents, all mice were healthy 63 days post-exposure and again positive for only enzootic agents. These results suggest that shoe debris might not be a significant biosecurity risk to laboratory mice, questioning the need for shoe covers or cleaners when entering experimental barrier vivaria.

microbiology↗

bioRxiv2024

The Impact of Host Genetics and/or its Microbiota on the Severity of Corynebacterium-Associated Hyperkeratosis in Outbred Athymic Nude Mice

Corynebacterium bovis (Cb), the etiology of Corynebacterium-associated hyperkeratosis (CAH) in nude mice, may impact research outcomes. Little is known about the differences in the course and severity of CAH in different outbred athymic nude mice stocks. Three genetic stocks (designated A, B, and C), 1 of which was obtained from 2 geographically separate colonies with distinct microbiota (A1 and A2), were inoculated topically with 1 x 108 CFUs of a pathogenic Cb field isolate (#7894; n = 6/stock) or sterile media (n=2/stock; controls). Clinical signs were assessed daily and scored 0 - 5 based on lesion severity. Mice were euthanized at 14 (A1, A2, B, and C) or 28 (B) days-post-inoculation (dpi), macroscopic changes documented, and 6 skin samples per mouse were obtained and histologically scored 0 - 4 based on the presence and severity of hyperkeratosis, acanthosis, inflammation, and bacterial colonies. No stock A1 or control mice developed clinical disease; 1 of 6 stock B mice developed mild CAH (mean peak clinical score [MPCS] - 0.33) at 14 dpi (14 day group) and 2 of 6 stock B (28 day group) developed mild CAH at 15 dpi (MPCS -0.33); and, all stock C and A2 mice developed significant clinical signs at 5 dpi (MPCS - 2.5 and 3, respectively) which resolved by 11 dpi. Despite differences in clinical presentation, all Cb-infected mice had hyperkeratosis and/or acanthosis with associated bacterial colonies. Stocks A1 and B, which had minimal or no clinical signs, were colonized with Corynebacterium amycolatum (Ca). In contrast, stocks C and A2 were not colonized with Ca, raising the possibility that Ca and/or other components of the skin microbiota may mitigate clinical signs but not necessarily all histopathologic changes associated with infection. These findings suggest host genetics and/or the skin microbiota can markedly influence the presentation of CAH in nude mice.

microbiology↗

bioRxiv2024

Chlamydia muridarum Causes Persistent Subclinical Infection and Elicits Innate and Adaptive Immune Responses in C57BL/6J, BALB/cJ and J:ARC(S) Mice Following Exposure to Shedding Mice

Chlamydia muridarum (Cm) has reemerged as a moderately prevalent infectious agent in research mouse colonies. Despite its experimental use, few studies evaluate Cms effects on immunocompetent mice following its natural route of infection. A Cm field isolate was administered (orogastric gavage) to 8-week-old female BALB/cJ (C) mice. After confirming shedding (through 95d), these mice were cohoused with naive C57BL/6J (B6), C, and Swiss (J:ARC[S]) mice (n=28/strain) for 30 days. Cohoused mice (n=3-6 exposed and 1-6 control/strain) were evaluated 7, 14, 21, 63, 120, and 180 days post-cohousing (DPC) via hemograms, serum biochemistry analysis, fecal qPCR, histopathology, and Cm MOMP immunohistochemistry. Immunophenotyping was performed on spleen (B6, C, S; n=6/strain) and intestines (B6; n=6) at 14 and 63 DPC. Serum cytokine concentrations were measured (B6; n=6 exposed and 2 control) at 14 and 63 DPC. All B6 mice were shedding Cm by 3 through 180 DPI. One of 3 C and 1 of 6 S mice began shedding Cm at 3 and 14 DPC, respectively, with the remaining shedding thereafter. Clinical pathology was nonremarkable. Minimal-to-moderate enterotyphlocolitis and gastrointestinal associated lymphoid tissue (GALT) hyperplasia was observed in 15 and 47 of 76 Cm-infected mice, respectively. Cm antigen was frequently detected in GALT-associated surface intestinal epithelial cells. Splenic immunophenotyping revealed increased monocytes and shifts in T cell population subsets in all strains/timepoints. Gastrointestinal immunophenotyping (B6) revealed sustained increases in total inflammatory cells and elevated cytokine production in innate lymphoid cells and effector T cells (large intestine). Elevated concentrations of pro-inflammatory cytokines were detected in the serum (B6). Results demonstrate that while clinical disease was not appreciated, 3 commonly utilized strains of mice are susceptible to chronic enteric Cm infection which may alter various immune responses. Considering the widespread use of mice to model GI disease, institutions should consider excluding Cm from their colonies.

microbiology↗

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↗

bioRxiv2023

Examining Horizontal Transmission of Nippostrongylus brasiliensis in Mice to Assess Biosecurity Risks

Nippostrongylus brasiliensis (Nb) infected mice are commonly used to study immune responses. There is no consensus regarding the biosecurity measures that should be employed when housing Nb-infected mice and rats. Transmission is reported to not occur when infected mice are co-housed with naive mice. We sought to determine what conditions, if any, favor horizontal transmission. Female NOD.Cg-Prkdcscid Il2rgtm1Wjl/Sz (NSG; n=12) and C57BL/6J (B6; n=12) mice inoculated with 750 Nb L3 larvae were cohoused with naive NSG (n=24) and B6 (n=24) mice at a ratio of 1 infected:2 naive mice per cage for 28 days within static microsiolator (MI) cages changed on a 14-day interval. We also assessed whether larval development to the L3 stage could occur when Nb egg-containing fecal pellets are maintained under 4 different environmental conditions (dry, moist, soiled bedding, and control) and whether infection results when naive NSG mice (n=9) are housed in MI cages with infective L3 larvae-spiked (10,000/cage) soiled bedding. NSG mice (n=3) were also gavaged with Nb eggs to model the potential for infection to occur following coprophagy. Both naive NSG (9 of 24) and B6 (10 of 24) mice cohoused with an infected cagemate passed Nb eggs in feces as early as 1 day and intermittently for varying periods following cohousing, presumably a result of coprophagy as adult worms were not detected at euthanasia. While eggs were able to develop into L3 larvae under 2 environmental conditions (moist and control), none of the NSG mice housed in cages with L3-spiked bedding or gavaged with eggs became infected with Nb. Findings demonstrate that horizontal transmission does not occur when mice are housed with Nb-shedding cagemates in static MI cages with a 14-day cage changing interval. Results from this study can be used to inform biosecurity practices when working with the Nb-infected mouse model.

immunology↗

bioRxiv2022

Assessing Mouse Kidney Parvovirus' Ability to Confound Research by Examining its Effects on Renally Excreted Chemotherapeutics and its Impact on Pathologic Endpoints in the Adenine Model of Chronic Kidney Disease

Mouse kidney parvovirus (MKPV) causes inclusion body nephropathy in severely immunocompromised mice and renal interstitial inflammation in immunocompetent mice. The purpose of this 2-part study was to determine the impact that MKPV may have on preclinical models as it relates to the pharmacokinetics of chemotherapeutics as well as its impact on the adenine diet model of chronic kidney disease. To assess the impact of MKPV on pharmacokinetics of 2 renally excreted chemotherapeutics commonly used in preclinical oncology studies, methotrexate and lenalidomide, blood and urine drug concentrations were measured in MKPV-infected or uninfected immunodeficient NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) and immunocompetent C57BL/6NCrl (B6) female mice. Differences in plasma pharmacokinetics were observed for methotrexate, but not for lenalidomide. Differences were most profound between uninfected NSG and B6 mice. The area under the curve (AUC) of methotrexate was 1.5-fold higher in uninfected NSG mice compared to infected NSG mice, 1.9-fold higher in infected B6 mice compared to uninfected B6 mice, and 4.3-fold higher in uninfected NSG mice compared to uninfected B6 mice. Renal clearance of both drugs was not impacted by MKPV infection but was generally lower in NSG mice. To assess the impact of MKPV on the adenine diet model of chronic kidney disease, MKPV-infected and uninfected B6 female mice were fed a 0.2% adenine diet and clinical and histopathologic features of disease were assessed over 8 weeks. Infection with MKPV did not have a significant impact on serum biomarkers of renal function such as BUN, creatinine, and SDMA; urine chemistry; or hemogram. However, infection did impact select histologic outcomes. MKPV-infected mice had significantly more foci of interstitial lymphoplasmacytic infiltrates than uninfected mice after 4 and 8 weeks of diet consumption, and significantly less interstitial fibrosis at week 8. Macrophage infiltrates and renal tubular injury, assessed using various immunohistochemical stains, were similar between groups. Together, these findings indicate that MKPV infection had minimal impact on the renal excretion of 2 chemotherapeutics and serum biomarkers of renal function. However, infection significantly impacted select histologic features of renal disease in the adenine diet model. While MKPV-free mice should be used in biomedical research, it is of the utmost importance in studies evaluating renal histology as an experimental outcome.

pathology↗

bioRxiv2022

Establishing the Median Infectious Dose (ID50) and Characterizing the Clinical Manifestations of Mouse, Rat, Cow, and Human Corynebacterium bovis Isolates in Select Immunocompromised Mouse Strains

Corynebacterium bovis (Cb), the etiology of hyperkeratotic dermatitis in various immunocompromised mouse strains, significantly impacts research in which infected mice are used. Although Cb has been isolated from a variety of species, including mice, rats, cows, and humans, little is known about the differences in the infectivity and clinical disease in mice associated with unique isolates. The infectious dose yielding colonization of 50% of the exposed population (ID50) and any associated clinical disease was determined for mouse (n=3), rat (n=1), cow (n=1), and human (n=2) Cb isolates in athymic nude mice (Hsd:Athymic Nude-Foxn1nu). The same investigations were undertaken comparing 2 of these murine isolates in 2 furred immunocompromised mouse strains (NSG [NOD.Cg-PrkdcscidIl2rgtm1Wjl/Sz] and NSG-S [NOD.Cg-PrkdcscidIl2rgtm1WjlTg(CMV-IL3,CSF2,KITLG)1Eav/MloySzJ]). To determine the ID50, mice (n=6/dose; 3 of each sex) were inoculated topically with 1 to 108 bacteria (10-fold increments) of each Cb isolate. Mice were scored (0 to 5) daily based on the severity of clinical signs for 14 days. On day 7 and 14 post-inoculation (PI), buccal and dorsal skin swabs were evaluated by aerobic culture to determine infection status. The mouse isolates yielded a lower ID50 (58 to 1,000 bacteria) as compared to the bovine (6,460 to 7,498 bacteria) and rat (10,000 bacteria) Cb isolates. Mice were not colonized and disease did not result when inoculated with human isolates. Mouse isolates produced varying clinical disease severity in nude mice (max score/isolate: 0 to 5). Despite significant immunodeficiency, furred NSG and NSG-S mice required a considerably higher (1,000- to 3,000-fold) inoculum to become colonized as compared to athymic nude mice. Once colonized, clinically detectable hyperkeratosis did not develop in these strains until 18 to 22 days PI. In contrast, in athymic nude mice that developed clinically detectable disease, hyperkeratosis was observed 6 to 14 days PI. In conclusion, there are significant differences in Cbs ID50, disease course, and severity between Cb isolates and among immunodeficient mouse strains.

microbiology↗

bioRxiv2022

Reemergence of the Murine Bacterial Pathogen Chlamydia muridarum in Laboratory Mouse Colonies

Chlamydia muridarum (Cm) was detected in mice from 2 colonies with lymphoplasmacytic pulmonary infiltrates using PCR and immunohistochemistry. This discovery was unexpected as Cm infection had not been reported in laboratory mice since the 1940s. A Cm specific PCR assay was developed and testing implemented for resident colonies from 8 vivaria from 3 academic institutions, 58 incoming mouse shipments from 39 academic institutions, and mice received from 55 commercial breeding colonies (4 vendors). To estimate Cms global prevalence in laboratory colonies, a database containing 11,387 metagenomic fecal microbiota samples from 120 institutions and a cohort of 900 diagnostic samples from 96 institutions were examined. Results indicate significant prevalence amongst academic institutions with Cm detected in 62.9% of soiled bedding sentinels from 3 institutions; 32.7% of incoming mouse shipments from 39 academic institutions; 14.2% of 120 institutions submitting microbiota samples; and 16.2% of the diagnostic sample cohort. All samples from commercial breeding colonies were negative. Additionally, naive NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mice exposed to Cm shedding mice and their soiled bedding developed clinical disease 21 to 28 days following exposure. These mice had a moderate-to-severe histiocytic and neutrophilic bronchointerstitial pneumonia with respiratory epithelium demonstrating inclusions, chlamydial major outer membrane protein immunostaining, and hybridization with a Cm reference sequence (GenBank accession no. U68436). Cm was isolated on HeLa 229 cells from lungs, cecum, and feces of a Cm infected NSG mouse. The considerable prevalence of Cm is likely attributed to widespread global interinstitutional distribution of unique mouse strains and failure to recognize that some of these mice were from enzootically infected colonies. Given that experimental Cm colonization of mice results in a robust immune response and, on occasion, pathology, natural infection may confound experimental results. Therefore, Cm should be excluded and eradicated from endemically infected laboratory mouse colonies.

microbiology↗