Name: cefoperazone-treated mouse model of clinically-relevant clostridium difficile strain r20291
Uploaded: 2016-12-10T13:00:00
Description: Watch this Scientific Journal Video about Cefoperazone-treated Mouse Model of Clinically-relevant Clostridium difficile Strain R20291 at JoVE.com

The authors would like to thank Trevor Lawley at the Wellcome Trust Sanger Institute for C. difficile R20291 spores and James S. Guy at the North Carolina State University College of Veterinary Medicine for Vero cells, both utilized in this manuscript. Animal histopathology was performed in the LCCC Animal Histopathology Core Facility at the University of North Carolina at Chapel Hill, with special assistance from Traci Raley and Amanda Brown. The LCCC Animal Histopathology Core is supported in part by an NCI Center Core Support Grant (2P30CA016086-40) to the UNC Lineberger Comprehensive Cancer Center. We would also like to thank Vincent Young, Anna Seekatz, Jhansi Leslie, and Cassie Schumacher for helpful discussions on the Vero cell cytotoxicity assay protocol. JAW is funded by the Ruth L. Kirschstein National Research Service Award Research Training grant T32OD011130 by NIH. CMT is funded by the career development award in metabolomics grant K01GM109236 by the NIGMS of the NIH.

Ethical Statement: 
The Institutional Animal Care and Use Committee (IACUC) at North Carolina State University College of Veterinary Medicine (NCSU) approved this study. The NCSU Animal Care and Use policy applies standards and guidelines set forth in the Animal Welfare Act and Health Research Extension Act of 1985. Laboratory animal facilities at NCSU adhere to guidelines set forth in the Guide for the Care and Use of Laboratory Animals. The animals&#39; health statuses were assessed daily, and moribund animal...

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This protocol characterizes the clinical course, including weight loss, bacterial colonization, toxin cytotoxicity, and histopathological changes in the gastrointestinal tract, of antibiotic-treated mice challenged with C. difficile R20291 spores. There are several critical steps within the protocol where attention to detail is essential. Accurate calculation of the C. difficile spore inoculum is critical. This calculation is based on the original C. difficile spore stock enumeration, which sho...

Clostridium difficile is an anaerobic, gram-positive, spore-forming bacillus that causes life-threatening diarrhea1. C. difficile infection (CDI) is associated with increased human morbidity and mortality and results in over $ 4.8 billion in healthcare costs per year1-4. In 2013, the Centers for Disease Control and Prevention categorized C. difficile as an urgent antibiotic resistance risk, indicating that it poses an urgent threat to public health1. Currently, antibiotic treatment with vancomycin and metronidazole are considered the standard of care for CDI5. Unfortunately, recurrence of CDI after successful treatment with antibiotics is high, occurring in 20 - 30% of patients2,5-7. Therefore, the discovery of novel therapeutics against this enteric pathogen is necessary. To evaluate therapeutics against C. difficile, an animal model approximating the human disease in a clinically-relevant strain is needed.
Initially, Koch&#39;s postulates were established for C. difficile in 1977 using a clindamycin-treated Syrian hamster model8. This model is still utilized today to investigate the effects of C. difficile toxins on pathogenesis9,10. However, CDI in the hamster model results in high mortality rates and does not approximate the chronic insidious disease manifestations that can be seen in humans with CDI 10,11. Based on the accessibility and reagent availability of murine platforms in research, a mouse model of CDI is relevant.
In 2008, a robust mouse model of CDI was established by treating mice with an antibiotic cocktail in drinking water (kanamycin, gentamicin, colistin, metronidazole, and vancomycin) for 3 days followed by an intraperitoneal injection of clindamycin12. This rendered mice susceptible to CDI and severe colitis. Depending on the inoculum dose administered, a range of clinical signs and lethality can be observed using this model. Since this time, various antibiotic regimens have been investigated that alter the murine gut microbiota, decreasing colonization resistance to the point where C. difficile can colonize the gastrointestinal tract (reviewed in Best et al. and Lawley &#38; Young)13,14.
More recently, a broad spectrum cephalosporin, cefoperazone, given in the drinking water for 5 or 10 days reproducibly renders mice susceptible to CDI15. Since administration of third-generation cephalosporins are associated with an increased risk of CDI in humans, use of the cefoperazone model more accurately reflects naturally-occurring disease16. Cefoperazone-treated mice susceptible to C. difficile have been challenged with both C. difficile spores and vegetative cells of a variety of strains ranging in clinical relevance and virulence17. Despite some of the original studies utilizing C. difficile vegetative cells as the infectious form, C. difficile spores are considered the major mode of transmission18.
In the last decade, C. difficile R20291, a NAP1/BI/027 strain, has emerged, causing epidemics of CDI19,20. We sought to determine the clinical course of disease when cefoperazone-treated mice were challenged with the clinically-relevant and genetically-tractable C. difficile strain, R20291. This protocol details the clinical course, including weight loss, bacterial colonization, toxin cytotoxicity, and histopathological changes in the gastrointestinal tract of mice challenged with C. difficile R20291 spores. Overall, this mouse model proves to be a valuable experimental platform for CDI approximating human disease. This characterized mouse model can thus be utilized to assess the effects of novel therapeutics on the amelioration of clinical disease and on the restoration of colonization resistance against C. difficile.

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		<tr height="21">
			<td height="21" style="height:21px;width:292px;">#62 Perisept Sporidicial Disinfectant Cleaner&#160;</td>
			<td style="width:143px;">SSS Navigator</td>
			<td style="width:119px;">48027</td>
			<td style="width:483px;">This product will require dilution as recommended by the manufacturer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">0.22 &#956;m filter</td>
			<td>Fisherbrand</td>
			<td>09-720-3</td>
			<td>Alternative to filter plate for indivdiual samples tested in the Vero Cell Assay</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">0.25% Trypsin-EDTA</td>
			<td>Gibco</td>
			<td>25200-056</td>
			<td>Needs to be heated in water bath at 37C prior to use</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">0.4% Trypan Blue</td>
			<td>Gibco</td>
			<td>15250-061</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">1% Peniciilin/Streptomycin</td>
			<td>Gibco</td>
			<td>15070-063</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">10% heat inactivated FBS</td>
			<td>Gibco</td>
			<td>16140-071</td>
			<td>Needs to be heated in water bath at 37C prior to use</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">1ml plastic syringe&#160;</td>
			<td>BD Medical Supplies</td>
			<td>309628</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">1X PBS</td>
			<td>Gibco</td>
			<td>10010-023</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">2 ml Micro Centrifuge Screw Cap</td>
			<td>Corning</td>
			<td>430917</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">96 well cell culture flat bottom plate</td>
			<td>Costar Corning</td>
			<td>CL3595</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">96 well filter plate</td>
			<td>Millipore</td>
			<td>MSGVS2210</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Adhesive Seal</td>
			<td>ThermoScientific</td>
			<td>AB-0558</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:292px;">Bacto Agar</td>
			<td style="width:143px;">Becton Dickinson</td>
			<td style="width:119px;">214010</td>
			<td>Part of TCCFA plates (see below)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:292px;">Bacto Proteose Peptone</td>
			<td style="width:143px;">Becton Dickinson</td>
			<td style="width:119px;">211684</td>
			<td>Part of TCCFA plates (see below)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Cefoperazone</td>
			<td>MP Bioworks</td>
			<td>199695</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Cefoxitine</td>
			<td>Sigma</td>
			<td>C47856</td>
			<td>Part of TCCFA plates (see below)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Clostridium difficile Antitoxin Kit</td>
			<td>Tech Labs</td>
			<td>T5000</td>
			<td>Used as control for Vero Cell Assay</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Clostridium difficile Toxin A</td>
			<td>List Biological Labs</td>
			<td>152C</td>
			<td>Positive control for Vero Cell Assay</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">D-cycloserine</td>
			<td>Sigma</td>
			<td>C6880</td>
			<td>Part of TCCFA plates (see below)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Distilled Water</td>
			<td>Gibco</td>
			<td>15230</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">DMEM 1X Media</td>
			<td>Gibco</td>
			<td>11965-092</td>
			<td>Needs to be heated in water bath at 37C prior to use</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Fructose</td>
			<td>Fisher</td>
			<td>L95500</td>
			<td>Part of TCCFA plates (see below)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hemocytometer</td>
			<td>Bright-Line, Sigma</td>
			<td>Z359629</td>
			<td></td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;width:292px;">KH2PO4</td>
			<td style="width:143px;">Fisher</td>
			<td style="width:119px;">P285-500</td>
			<td>Part of TCCFA plates (see below)</td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;width:292px;">MgSO4 (anhydrous)</td>
			<td style="width:143px;">Sigma</td>
			<td style="width:119px;">M2643</td>
			<td>Part of TCCFA plates (see below)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:292px;">Millex-GS 0.22 &#956;m filter</td>
			<td style="width:143px;">Millex-GS</td>
			<td style="width:119px;">SLGS033SS</td>
			<td style="width:483px;">Filter for TCCFA plates&#160;</td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;width:292px;">Na2HPO4</td>
			<td style="width:143px;">Sigma</td>
			<td style="width:119px;">S-0876</td>
			<td>Part of TCCFA plates (see below)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">NaCl</td>
			<td style="width:143px;">Fisher</td>
			<td style="width:119px;">S640-3</td>
			<td>Part of TCCFA plates (see below)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Number 10 disposable scalpel blade</td>
			<td>Miltex, Inc</td>
			<td>4-410</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">PCR Plates</td>
			<td>Fisherbrand</td>
			<td>14230244</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Plastic petri dish</td>
			<td>Kord-Valmark Brand</td>
			<td>2900</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sterile plastic L-shaped cell spreader</td>
			<td>Fisherbrand</td>
			<td>14-665-230</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Syringe Stepper</td>
			<td>Dymax Corporation</td>
			<td>T15469</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Taurocholate</td>
			<td>Sigma</td>
			<td>T4009</td>
			<td>Part of TCCFA plates (see below)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Ultrapure distilled water</td>
			<td>Invitrogen</td>
			<td>10977-015</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:292px;">C57BL/6J Mice</td>
			<td style="width:143px;">The Jackson Laboratory</td>
			<td align="right" style="width:119px;">664</td>
			<td style="width:483px;">Mice should be 5-8 weeks of age</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Olympus BX43F light microscope</td>
			<td style="width:143px;">Olympus Life Science</td>
			<td style="width:119px;"></td>
			<td style="width:483px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">DP27 camera</td>
			<td style="width:143px;">Olympus Life Science</td>
			<td style="width:119px;"></td>
			<td style="width:483px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">cellSens Dimension software&#160;</td>
			<td style="width:143px;">Olympus Life Science</td>
			<td style="width:119px;"></td>
			<td style="width:483px;"></td>
		</tr>
	</tbody>
</table>

cefoperazone-treated mouse model of clinically-relevant clostridium difficile strain r20291

Clostridium difficile is an anaerobic, gram-positive, spore-forming enteric pathogen that is associated with increasing morbidity and mortality and consequently poses an urgent threat to public health. Recurrence of a C. difficile infection (CDI) after successful treatment with antibiotics is high, occurring in 20-30% of patients, thus necessitating the discovery of novel therapeutics against this pathogen. Current animal models of CDI result in high mortality rates and thus do not approximate the chronic, insidious disease manifestations seen in humans with CDI. To evaluate therapeutics against C. difficile, a mouse model approximating human disease utilizing a clinically-relevant strain is needed. This protocol outlines the cefoperazone mouse model of CDI using a clinically-relevant and genetically-tractable strain, R20291. Techniques for clinical disease monitoring, C. difficile bacterial enumeration, toxin cytotoxicity, and histopathological changes throughout CDI in a mouse model are detailed in the protocol. Compared to other mouse models of CDI, this model is not uniformly lethal at the dose administered, allowing for the observation of a prolonged clinical course of infection concordant with the human disease. Therefore, this cefoperazone mouse model of CDI proves a valuable experimental platform to assess the effects of novel therapeutics on the amelioration of clinical disease and on the restoration of colonization resistance against C. difficile.

During a representative study, 5-week-old C57BL/6 WT mice were pretreated with cefoperazone in their drinking water (0.5 mg/ml) for 5 days and allowed a 2-day wash out with regular drinking water. Mice were challenged with 105 spores of C. difficile R20291 via oral gavage on day 0 (Figure 1A). Mice were monitored for weight loss and clinical signs (lethargy, inappetence, diarrhea, and hunched posture) of CDI for 14 days. The challenge of C57BL/6 WT mic...

Watch this Scientific Journal Video about Cefoperazone-treated Mouse Model of Clinically-relevant Clostridium difficile Strain R20291 at JoVE.com

Cefoperazone-treated Mouse Model of Clinically-relevant Clostridium difficile Strain R20291

This protocol outlines the cefoperazone mouse model of Clostridium difficile infection (CDI) using a clinically-relevant and genetically-tractable strain, R20291. Emphasis on clinical disease monitoring, C. difficile bacterial enumeration, toxin cytotoxicity, and histopathological changes throughout CDI in a mouse model are detailed in the protocol.

Cefoperazone-treated Mouse Model of Clinically-relevant Clostridium difficile Strain R20291

Clostridium difficile is an anaerobic, gram-positive, spore-forming enteric pathogen that is associated with increasing morbidity and mortality and ...

The overall goal of this protocol is to provide a step by step guide for implementing the cefoperazone mouse model of Clostridium difficile infection, with special emphasis on clinical disease monitoring, bacteria enumeration, toxin cytotoxicity, and histopathologic changes post challenge. This detailed protocol will help researchers accurately execute a mouse model of Clostridium difficile infection, which is essential for studying the pathogenesis of this bacterium and accessing novel therapeutics. The main advantage of using this mouse model is that exposure to one antibiotic for five days renders mice susceptible to colonization of C.difficile and for a prolonged clinical course of infection concurrent with human disease.To begin, take the C.difficile stock strain of interest and vortex. In a laminar flow hood, dilute the stock in sterile water in a screw cap tube to a concentration of ten to the fifth spores per 25 microliters. Label the mixture as spore inoculum and place the tube into a 65 degree Celsius water bath for 20 minutes.Next, in the laminar flow hood, pipette 50 microliters of the heated spore inoculum into a sterile microcentrifuge tube and pass it into the anaerobic chamber until further use. Load the remaining spore inoculum into a one milliliter syringe attached to a sterile bulb tipped gastric gavage needle. In a laminar flow hood, take a subject mouse and immobilize the head by restraining the animal gently by the loose skin of the neck and back.Using the index finger, and ensuring the animal does not vocalize or show signs of distress, further immobilize the animal's head and elongate the esophagus. Maintain the mouse in an upright, vertical position and gently pass the gavage needle into the side of the mouth. Direct the gavage needle along the roof of the mouth and slowly advance it into the esophagus.Once the needle is approximately halfway into the esophagus, inject 25 microliters of spore inoculum and then gently withdraw the needle. Return the animal to its cage, and observe it for any signs of coughing or respiratory distress that may indicate inadvertent tracheal administration. Next, take the spore inoculum aliquot stored previously in the anaerobic chamber, and any remaining gavage spore inoculum, and make one to ten serial dilutions in 180 microliters of 1x PBS.Perform four to five of these dilutions. Using aseptic technique, transfer 100 microliters of each serial dilution into an individual TCCFA plate. Taking a new sterile L-shaped spreader each time, evenly distribute the dilution inocula on each plate.Incubate the plates under anaerobic conditions for 24 hours at 37 degrees Celsius. Finally, count the C.difficile colonies on each dilution plate and calculate the colony forming units to obtain the infective dose administered to the mice. To collect fecal samples from mice for assessment, first lightly but firmly restrain the subject mouse by the loose skin on the neck and back, ensuring the animal is not in distress.Using the pinky finger, gently lift the animal's tail, exposing the anus. Hold a sterile microcentrifuge tube of known weight directly under the animal's anus, ensuring the tube does not directly touch the mouse. When the animal defecates, collect the fecal pellet in the tube.Store the tube at room temperature until all necessary samples are collected. Weigh the tubes containing feces on an analytical scale and record the mass to four decimal places. Calculate the weight of the fecal pellet by subtracting the weight of the tube.Next, calculate a one to ten dilution of the contents and resuspend into 1x PBS. Use the tip of the pipette to gently disrupt the fecal matter into solution. Incubate the samples at room temperature for 30 minutes, allowing the contents to settle.Maintaining the solutions anaerobically, make serial dilutions for each sample in 1x PBS. Transfer 100 microliters of each serial dilution onto TCCFA plates. Use a sterile L-shaped spreader and evenly apply the media to the plates.Incubate the plates in anaerobic conditions at 37 degrees celsius for 24 hours. Finally, enumerate the C.difficile colonies and calculate the colony forming unit per gram of fecal content. This figure shows mouse weight in the days following challenge with C.difficile R20291.At day zero, the baseline weight is set to 100. Average mouse bodyweight was measured each day following, for 14 days. A significant decrease in weight was observed in challenged mice on days two to seven post challenge.Mice appeared to recover and regain weight after this point. Here, C.difficile load in the feces in the days post challenge are shown. At 24 hours post challenge, all mice were colonized with 10 to the seventh CFUs per gram of feces.This load had decreased by day seven onwards, though C.difficile is still present. Histopathologic examination of mice over the time course of the infection showed the most significant pathologic changes in the cecum. Total cecal histologic scores were significantly different between day zero and days two and four post challenge.Generally, individuals new to this mouse model may struggle with the calculation and preparation of the spore inoculum used to challenge the mice and the calculation of fecal C.difficile bacterial load. While attempting this protocol it's important to remember that modifications of the dose or strain of C.difficile spores administered to mice may alter the outcome of this model.

cefoperazone-treated-mouse-model-clinically-relevant-clostridium

Research

JoVE Journal

Immunology and Infection

Culturing and Maintaining Clostridium difficile in an Anaerobic Environment

Clostridium difficile is a Gram-positive, anaerobic, sporogenic bacterium that is primarily responsible for antibiotic associated diarrhea (AAD) and is a significant nosocomial pathogen. C. difficile is notoriously difficult to isolate and cultivate and is extremely sensitive to even low levels of oxygen in the environment. Here, methods for isolating C. difficile from fecal samples and subsequently culturing C. difficile for preparation of glycerol stocks for long-term storage are presented. Techniques for preparing and enumerating spore stocks in the laboratory for a variety of downstream applications including microscopy and animal studies are also described. These techniques necessitate an anaerobic chamber, which maintains a consistent anaerobic environment to ensure proper conditions for optimal C. difficile growth. We provide protocols for transferring materials in and out of the chamber without causing significant oxygen contamination along with suggestions for regular maintenance required to sustain the appropriate anaerobic environment for efficient and consistent C. difficile cultivation.

Culturing and Maintaining Clostridium difficile in an Anaerobic Environment

Clostridium difficile is a pathogenic bacterium that is a strict anaerobe and causes antibiotic associated diarrhea (AAD). Here, methods for isolating, culturing and maintaining C. difficile vegetative cells and spores are described. These techniques necessitate an anaerobic chamber, which requires regular maintenance to ensure proper conditions for optimal C. difficile cultivation.

Clostridium  difficile is a Gram-positive, anaerobic, sporogenic bacterium  that is primarily responsible for antibiotic associated diarrhea (AAD) and is ...

A Protocol to Characterize the Morphological Changes of Clostridium difficile in Response to Antibiotic Treatment

Assessment of antibiotic action with new drug development directed towards anaerobic bacteria is difficult and technically demanding. To gain insight into possible MOA, morphologic changes associated with antibiotic exposure can be visualized using scanning electron microscopy (SEM). Integrating SEM imaging with traditional kill curves may improve our insight into drug action and advance the drug development process. To test this premise, kill curves and SEM studies were conducted using drugs with known but different MOA (vancomycin and metronidazole). C. difficile cells (R20291) were grown with or without the presence of antibiotic for up to 48 h. Throughout the 48 h interval, cells were collected at multiple time points to determine antibiotic efficacy and for imaging on the SEM. Consistent with previous reports, vancomycin and metronidazole had significant bactericidal activity following 24 h of treatment as measured by colony-forming unit (CFU) counting. Using SEM imaging we determined that metronidazole had significant effects on cell length (&#62; 50% reduction in cell length for each antibiotic; P&#60; 0.05) compared to controls and vancomycin. While the phenotypic response to drug treatment has not been documented previously in this manner, they are consistent with the drug&#39;s MOA demonstrating the versatility and reliability of the imaging and measurements and the application of this technique for other experimental compounds.

A Protocol to Characterize the Morphological Changes of Clostridium difficile in Response to Antibiotic Treatment

Antibiotic efficacy is most commonly determined by conducting killing kinetic studies and measuring colony forming units (CFUs). By integrating scanning electron microscopy (SEM) with these standard methods, we can distinguish the pharmacological effects of treatment between different antibiotics.

Assessment of antibiotic action with new drug development directed towards anaerobic bacteria is difficult and technically demanding. To gain insight into ...

Influenza A Virus Studies in a Mouse Model of Infection

Influenza viruses cause over 500,000 deaths worldwide1 and are associated with an annual cost of 12 - 14 billion USD in the United States alone considering direct medical and hospitalization expenses and work absenteeism2. Animal models are crucial in Influenza A virus (IAV) studies to evaluate viral pathogenesis, host-pathogen interactions, immune responses, and the efficacy of current and/or novel vaccine approaches as well as antivirals. Mice are an advantageous small animal model because their immune system is evolutionarily similar to that found in humans, they are available from commercial vendors as genetically identical subjects, there are multiple strains that can be exploited to evaluate the genetic basis of infections, and they are relatively inexpensive and easy to manipulate. To recapitulate IAV infection in humans via the airways, mice are first anesthetized prior to intranasal inoculation with infectious IAVs under proper biosafety containment. After infection, the pathogenesis of IAVs is determined by monitoring daily the morbidity (body weight loss) and mortality (survival) rate. In addition, viral pathogenesis can also be evaluated by assessing virus replication in the upper (nasal mucosa) or lower (lungs) respiratory tract of infected mice. Humoral responses upon IAV infection can be rapidly evaluated by non-invasive bleeding and secondary antibody detection assays aimed at detecting the presence of total or neutralizing antibodies. Here, we describe the common methods used to infect mice intranasally (i.n) with IAV and evaluate pathogenesis, humoral immune responses and protection efficacy.

Influenza A viruses (IAVs) are important human respiratory pathogens. To understand the pathogenicity of IAVs and to perform preclinical testing of novel vaccine approaches, animal models mimicking human physiology are required. Here, we describe techniques to evaluate IAV pathogenesis, humoral responses and vaccine efficacy using a mouse model of infection.

Influenza viruses cause over 500,000 deaths worldwide1 and are associated with an annual cost of 12 - 14 billion USD in the United States alone ...

A Protein Microarray Assay for Serological Determination of Antigen-specific Antibody Responses Following Clostridium difficile Infection

We provide a detailed overview of a novel high-throughput protein microarray assay for the determination of anti-Clostridium difficile antibody levels in human sera and in separate preparations of polyclonal intravenous immunoglobulin (IVIg). The protocol describes the methodological steps involved in sample preparation, printing of arrays, assay procedure, and data analysis. In addition, this protocol could be further developed to incorporate diverse clinical samples including plasma and cell culture supernatants. We show how protein microarray can be used to determine a combination of isotype (IgG, IgA, IgM), subclass (IgG1, IgG2, IgG3, IgG4, IgA1, IgA2), and strain-specific antibodies to highly purified whole C. difficile toxins A and B (toxinotype 0, strain VPI 10463, ribotype 087), toxin B from a C. difficile toxin-B-only expressing strain (CCUG 20309), a precursor form of a B fragment of binary toxin, pCDTb, ribotype-specific whole surface layer proteins (SLPs; 001, 002, 027), and control proteins (tetanus toxoid and Candida albicans). During the experiment, microarrays are probed with sera from individuals with C. difficile infection (CDI), individuals with cystic fibrosis (CF) without diarrhea, healthy controls (HC), and from individuals pre- and post-IVIg therapy for the treatment of CDI, combined immunodeficiency disorder, and chronic inflammatory demyelinating polyradiculopathy. We encounter significant differences in toxin neutralization efficacies and multi-isotype specific antibody levels between patient groups, commercial preparations of IVIg, and sera before and following IVIg administration. Also, there is a significant correlation between microarray and enzyme-linked immunosorbent assay (ELISA) for antitoxin IgG levels in serum samples. These results suggest that microarray could become a promising tool for profiling antibody responses to C.difficile antigens in vaccinated or infected humans. With further refinement of antigen panels and a reduction in production costs, we anticipate that microarray technology may help optimize and select the most clinically useful immunotherapies for C. difficile infection in a patient-specific manner.

A Protein Microarray Assay for Serological Determination of Antigen-specific Antibody Responses Following Clostridium difficile Infection

This article describes a simple protein microarray method for profiling humoral immune responses to a 7-plex panel of highly purified Clostridium difficile antigens in human sera. The protocol can be extended for the determination of specific antibody responses in preparations of polyclonal intravenous immunoglobulin.

We provide a detailed overview of a novel high-throughput protein microarray assay for the determination of anti-Clostridium difficile antibody levels in ...

A Purification and In Vitro Activity Assay for a (p)ppGpp Synthetase from Clostridium difficile

Kinase and pyrophosphokinase enzymes transfer the gamma phosphate or the beta-gamma pyrophosphate moiety from nucleotide triphosphate precursors to substrates to create phosphorylated products. The use of &#947;-32-P labeled NTP precursors allows simultaneous monitoring of substrate utilization and product formation by radiography. Thin layer chromatography (TLC) on cellulose plates allows rapid separation and sensitive quantification of substrate and product. We present a method for utilizing the thin-layer chromatography to assay the pyrophosphokinase activity of a purified (p)ppGpp synthetase. This method has previously been used to characterize the activity of cyclic nucleotide and dinucleotide synthetases and is broadly suitable for characterizing the activity of any enzyme that hydrolyzes a nucleotide triphosphate bond or transfers a terminal phosphate from a phosphate donor to another molecule.

A Purification and In Vitro Activity Assay for a pppGpp Synthetase from Clostridium difficile

Here, we describe a method for purifying histidine-tagged pyrophosphokinase enzymes and utilizing thin layer chromatography of radiolabelled substrates and products to assay for the enzymatic activity in vitro. The enzyme activity assay is broadly applicable to any kinase, nucleotide cyclase, or phosphor-transfer reaction whose mechanism includes nucleotide triphosphate hydrolysis.

Kinase and pyrophosphokinase enzymes transfer the gamma phosphate or the beta-gamma pyrophosphate moiety from nucleotide triphosphate precursors to ...

A Controlled Mouse Model for Neonatal Polymicrobial Sepsis

Neonatal sepsis remains a global burden. A preclinical model to screen effective prophylactic or therapeutic interventions is needed. Neonatal mouse polymicrobial sepsis can be induced by injecting cecal slurry intraperitoneally into day of life 7 mice and monitoring them for the following week. Presented here are the detailed steps necessary for the implementation of this neonatal sepsis model. This includes making a homogeneous cecal slurry stock, diluting it to a weight- and litter-adjusted dose, an outline of the monitoring schedule, and a definition of observed health categories used to define humane endpoints. The generation of a homogeneous cecal slurry stock from pooled donors allows for the administration into many litters over time, reducing the variation between donors, and preventing the use of potentially toxic glycerol. The monitoring strategy used allows for the anticipation of survival outcome and the identification of mice that would later progress to death, allowing for an earlier identification of the humane endpoint. Two main behavioral features are used to define the health scores, namely, the ability of the neonatal mice to right themselves when placed on their back and their level of mobility. These criteria could potentially be applied to address humane endpoints in other studies of neonatal disease in mice, as long as a pilot study is performed to confirm accuracy. In conclusion, this approach provides a standardized method to model newborn sepsis in mice, while providing resources to assess animal welfare used to define early humane endpoints for challenged animals.

This protocol provides the necessary steps to establish and evaluate neonatal sepsis in 7-day-old mice.

Neonatal sepsis remains a global burden. A preclinical model to screen effective prophylactic or therapeutic interventions is needed. Neonatal mouse ...

Measurement of Pulse Propagation Velocity, Distensibility and Strain in an Abdominal Aortic Aneurysm Mouse Model

An abdominal aortic aneurysm (AAA) is defined as a localized dilation of the abdominal aorta that exceeds the maximal intraluminal diameter (MILD) by 1.5 times of its original size. Clinical and experimental studies have shown that small aneurysms may rupture, while a subpopulation of large aneurysms may remain stable. Thus, in addition to the measurement of intraluminal diameter of the aorta, knowledge of structural traits of the vessel wall may provide important information to assess the stability of the AAA. Aortic stiffening has recently emerged as a reliable tool to determine early changes in the vascular wall. Pulse propagation velocity (PPV) along with the distensibility and radial strain are highly useful ultrasound-based methods relevant for assessing aortic stiffness. The primary purpose of this protocol is to provide a comprehensive technique for the use of ultrasound imaging system to acquire images and analyze the structural and functional properties of the aorta as determined by MILD, PPV, distensibility and radial strain.

This manuscript describes a detailed protocol for using high frequency ultrasound imaging to measure luminal diameter, pulse propagation velocity, distensibility and radial strain on a mouse model of abdominal aortic aneurysm.

An abdominal aortic aneurysm (AAA) is defined as a localized dilation of the abdominal aorta that exceeds the maximal intraluminal diameter (MILD) by 1.5 ...

Constructing Mutants in Serotype 1 Streptococcus pneumoniae strain 519/43

Streptococcus pneumoniae serotype 1 remains a huge problem in low-and-middle income countries, particularly in sub-Saharan Africa. Despite its importance, studies in this serotype have been hindered by the lack of genetic tools to modify it. In this study, we describe a method to genetically modify a serotype 1 clinical isolate (strain 519/43). Interestingly, this was achieved by exploiting the Pneumococcus&#8217; ability to naturally acquire DNA. However, unlike most pneumococci, the use of linear DNA was not successful; to mutate this important strain, a suicide plasmid had to be used. This methodology has provided the means for a deeper understanding of this elusive serotype, both in terms of its biology and pathogenicity. To validate the method, the major known pneumococcal toxin, pneumolysin, was mutated because it has a well-known and easy to follow phenotype. We showed that the mutant, as expected, lost its ability to lyse red blood cells. By being able to mutate an important gene in the serotype of interest, we were able to observe different phenotypes for loss of function mutants upon intraperitoneal and intranasal infections from the ones observed for other serotypes. In summary, this study proves that strain 519/43 (serotype 1) can be genetically modified.

Constructing Mutants in Serotype 1 Streptococcus pneumoniae strain 519/43

Here, we describe a S. pneumoniae serotype 1 strain 519/43 that can be genetically modified by using its ability to naturally acquire DNA and a suicide-plasmid. As proof of principle, an isogenic mutant in the pneumolysin (ply) gene was made.

Streptococcus pneumoniae serotype 1 remains a huge problem in low-and-middle income countries, particularly in sub-Saharan Africa. Despite its importance, ...

Experimental Autoimmune Uveitis: An Intraocular Inflammatory Mouse Model

Experimental Autoimmune Uveitis (EAU) is driven by immune cells responding to self-antigens. Many features of this non-infectious, intraocular inflammatory disease model recapitulate the clinical phenotype of posterior uveitis affecting humans. EAU has been used reliably to study the efficacy of novel inflammatory therapeutics, their mode of action and to further investigate the mechanisms that underpin disease progression of intraocular disorders. Here, we provide a detailed protocol on EAU induction in the C57BL/6J mouse - the most widely used model organism with susceptibility to this disease. Clinical assessment of disease severity and progression will be demonstrated using fundoscopy, histological examination and fluorescein angiography. The induction procedure involves subcutaneous&#160;injection of an emulsion containing a peptide (IRBP1-20) from the ocular protein interphotoreceptor retinoid binding protein (also known as retinol binding protein 3), Complete Freund&#39;s Adjuvant (CFA) and supplemented with killed Mycobacterium tuberculosis. Injection of this viscous emulsion on the back of the neck is followed by a single intraperitoneal injection of Bordetella pertussis toxin. At the onset of symptoms (day 12-14) and under general anesthesia, fundoscopic images are taken to assess disease progression through clinical examination. These data can be directly compared with those at later timepoints and peak disease (day 20-22) with differences analyzed. At the same time, this protocol allows the investigator to assess potential differences in vessel permeability and damage using fluorescein angiography. EAU can be induced in other mouse strains - both wildtype or genetically modified - and combined with novel therapies offering flexibility for studying drug efficacy and/or disease mechanisms.

In this report we present a protocol that allows the investigator to generate a mouse model of intraocular uveitis. More commonly referred to as experimental autoimmune uveitis (EAU), this established model captures many aspects of human disease. Herein, we will describe how to induce and monitor disease progression using several readouts.

Experimental Autoimmune Uveitis (EAU) is driven by immune cells responding to self-antigens. Many features of this non-infectious, intraocular ...

Mouse Model of Oleic Acid-Induced Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is a significant threat to critically ill patients with a high fatality rate. Pollutant exposure, cigarette smoke, infectious agents, and fatty acids can induce ARDS. Animal models can mimic the complex pathomechanism of the ARDS. However, each of them has limitations. Notably, oleic acid (OA) is increased in critically ill patients with harmful effects on the lung. OA can induce lung injury by emboli, disrupting tissue, altering pH, and impairing edema clearance. OA-induced lung injury model resembles various features of ARDS with endothelial injury, increased alveolar permeability, inflammation, membrane hyaline formation, and cell death. Herein, induction of lung injury is described by injecting OA (in salt form) directly into the lung and intravenously in a mouse since it is the physiological form of OA at pH 7. Thus, the injection of OA in the salt form is a helpful animal model to study lung injury/ARDS without causing emboli or altering the pH, thereby getting close to what is happening in critically ill patients.

The present protocol describes a lung injury model in mice using oleic acid to mimic acute respiratory distress syndrome (ARDS). This model increases the inflammatory mediators on edema and decreases lung compliance. Oleic acid is used in the salt form (oleate) since this physiological form avoids the risk of embolism.

Acute respiratory distress syndrome (ARDS) is a significant threat to critically ill patients with a high fatality rate. Pollutant exposure, cigarette ...