You injected what into your face?

              Botulinum toxin is the most lethal protein known to man. Botulinum toxin is produced by Clostridium botulinum, an anaerobic gram positive spore forming rod. C. botulinum and its spores are found widely distributed in nature. There are seven types of C. botulinum based on the form of the toxin they produce. Toxin A, B, E, and F are the only ones that have been associated with causing human botulism. The botulism toxin is a very potent neurotoxin formed during bacterial growth. Only 75ng is enough to kill a person of about 165lbs. A single teaspoon of botulinum toxin is enough to kill about 1.2 billion people. The toxin functions by blocking motor nerve terminals at the neuromuscular junction (see diagram below).   Progression of paralysis usually starts with the eyes and face and progresses downward to the throat chest and extremities. Once the diaphragm and the chest muscles become affected respiration is inhibited and without intervention this results in death. There are three common ways that you can get botulism: foodborne botulism, infant botulism, and wound botulism. The first way, ingestion of foods containing the botulism toxins is the most common and occurs after the consumption of improperly processed and inadequately cooked home preserved foods. I like to make my own salsa and when I do I usually make a lot. I preserve the extra salsa I make by canning it. There are several precautions that must be taken to ensure that I don’t kill myself with the deadly food poison botulism. The USDA gives some recommendations that I follow and these include washing food, peeling some fresh food, hot packing (this is basically boiling it before canning), adding acids (lemon juice or vinegar), using appropriate jars and lids, processing jars in boiling water or pressure canner. Key factors to reduce the growth of Clostridium botulinum include pH less than 4.6 and salt concentration from 4 to 5%. The second way to get botulism is Infant botulism. Honey is the one dietary reservoir of Clostridium botulinum that has been linked to infant botulism. If you have ever heard not to give children under 12 months honey this is why. So what do we do with such a potent toxin? Many governments around the world have tried to weaponize botulinum toxin. The U.S. along with several other contries weaponized it in response to suspicions of Nazi Germany’s biological warfare development in 1941. Biological weapons were outlawed in 1972 by the Biological weapons convention but the threat of a possible terrorist use still remains. The FDA has produced a very interesting video on the history of botulinum toxin as a biological warfare agent(see below). So what else can we do with botulinum toxin? The drug BOTOX is actually botulinum toxin type A. It has many uses some of which include: to temporarily smooth frown lines (wrinkles between the eyebrows), to control severe underarm sweating, strabismus (an eye muscle problem that causes the eyes to turn inward or outward) and blepharospasm (uncontrollable tightening of the eyelid muscles that may cause blinking, squinting, and abnormal eyelid movements) and more. For more information about Clostridium botulinum /botulism visit the following  FDA , CDC , Bioterrorism.

Detection of the Hepatitis C Virus

     Because the clinical characteristics are the same for all types of acute viral hepatitis, laboratory testing is needed to identify the specific viral cause of illness. Confirmation of acute hepatitis C results when a negative test result occurs for Hepatitis A Virus and Hepatitis B Virus with one of the following: Antibody to hepatitis C virus (anti-HCV) screening-test-positive with a signal to cut-off ratio predictive of a true positive by CDC guidelines, Hepatitis C virus recombinant immunoblot assay (HCV RIBA) positive, or nucleic acid test (NAT) for HCV RNA positive. The two main classes of assays used in the diagnosis and management of HCV infection: serologic assays that detect specific antibody to hepatitis C virus (anti-HCV) and molecular assays that detect viral nucleic acid. The development of molecular assays for blood borne viral infections has made it possible to detect acute infections at an earlier stage than would be possible with conventional techniques and to measure the concentration of virus present in blood during the acute or chronic phases of infection. Molecular methods proved most useful for the identification of viruses that are either completely unable to be cultivated or can be cultivated only with great difficulty.  Several commercial assays for HCV genotyping are also available for use in clinical laboratories. Detection of HCV genotype is the most significant predictor of response to anti-HCV therapy and is used to predict treatment response and guide duration of therapy. The importance of nucleic acid testing over antibody testing can be seen in the blood banking industry. It is estimated that 9.7 Hepatitis C virus infected units per million donations go undetected by Antibody assays. With the use of nucleic acid test this risk is reduced to 2.72 infectious units per million donations. Nucleic acid testing reduces the detection window by an average of 25.8 days over antibody testing. Hepatitis C virus nucleic acid testing clearly increases the detection rate of HCV in donations that are immunosilent and help prevent these specimens from entering the blood supply. There are currently multiple nucleic acid assays available that use different methodology for the detection of the HCV nucleic acid RNA. For a full listing of the currently availible FDA approved testing methods for HCV refer to the following link. FDA approved

Your nice cool air is not so nice!

       In 1976 the American Legion gathered in Philadelphia Pennsylvania at the Bellevue Stratford Hotel to prepare for a bicentennial celebration when 221 people were stricken with an unknown respiratory disease. Every known antibiotic was tried, most unsuccessfully, however erythromycin seemed to somewhat help. In the end, 34 people died. Two biologists, McDade and Shepard, with the CDC discovered that the causative agent was a small fastidious gram negative rod. They decided to name the bacteria for the unfortunate victims of the American Legion hence the name Legionella. The outbreak was thought to have been caused by contaminated water in the hotel’s air-conditioning system. Legionella bacteria are naturally occurring aquatic bacteria that grow in warm water, particularly in cooling towers, water heaters, and potable-water plumbing. Legionella species are intracellular pathogens residing inside of macrophages. Because of this, the antibiotics used to treat legionaire’s disease must remain active inside the macrophages. Currently macrolides and quinolones are the first choice of treatment.  Tetracyclines are also likely effective but Beta-lactam antibiotics are not. The outbreak in 1976 was a result of Legionella pneumophilia serogroup 1.  Legionella pneumophilia is the most common isolate accounting for 70-90%. There are 49 different Legionella species, 20 of which have been reported to infect humans. In addition, there are at least 16 different serogroups. Each year, between 8,000 and 18,000 people are hospitalized with Legionnaires' disease in the U.S. The actual number is thought to be higher since many infections are thought to be either not reported or not diagnosed. People most at risk of getting sick from the bacteria are people over 50, as well as people who are current or former smokers, or those who have a chronic lung disease like emphysema. The majority of the people at the American legion convention were over 50 making them at higher risk. People who take immunosuppressives are also at a higher risk. This was the case in a 47 year old man who received a heart transplant at UAB hospital in February 1986. In April 1986 a lung biopsy was performed on a lung lesion that had been identified. From that biopsy a new species of Legionella was identified and named Legionella birminghamensis.  Legionella is an obligate aerobe and best grown on BCYEa agar in about 2-5 days in the lab.  I have also added a short video that goes into more detail on the life cycle of Legionella.

Hepatitis C Virus

       Since its discovery in 1989, hepatitis C virus (HCV) has been recognized as a major cause of chronic liver disease worldwide. Hepatitis C virus is the leading cause of liver transplantation in developed countries, and the most common chronic blood borne infection in the USA. Using the most conservative estimates the prevalence of Hepatitis C Virus (HCV) in the US is estimated at 5.2 million people. That is approximately 2% of the US population. The CDC list an average of 12,000 deaths per year caused by chronic liver disease as a result of Hepatitis C Virus. Originally identified as non-A, non-B hepatitis (NANBH) has three common modes of transmission. These are blood to blood transfusions, sharing of injection equipment by illicit drug users and inadequately sterilized or unsterilized equipment in healthcare setting. Although less likely Hepatitis C Virus can also be spread from HCV infected child from mother, during sex with HCV infected person, sharing of personal items contaminated with blood. Human beings are the only known reservoirs for HCV. Species Hepatitis C virus is a positive stranded RNA virus of the family Flaviviridae, genus hepacivirus, that is approximately 9.6 kb in length. There are six major genotypes or clades numbered 1 to 6 with more than 70 confirmed or provisional subtypes identified.

       The gold standard for confirmation of HCV is liver biopsy making laboratory test for HCV much more practical. There are many blood tests available to detect HCV. Available assays include screening test for antibody such as enzyme immunoassay and enhanced chemiluminescence immunoassay. Also available are molecular assay to detect viral RNA such as polymerase chain reaction and transcription mediated amplification. Molecular assay are available in both qualitative and quantitative. Molecular assays are also available for genotyping of Hepatitis C virus.

        I will go into much more detail throughout the semester but I hope this introduction will provide a foundation for future HCV post.

Cantaloupe! yummy!

                You sit down for breakfast and decide you’re going to have that juicy slice of cantaloupe you have had your eye on. Little do you know that because you had that craving for some cantaloupe you will now die within 30 days. Does this sound farfetched?  Last fall that is exactly what happened to 30 people in the US. This week in infectious diseases we looked at infections of the central nervous system. In lab we received a cerebrospinal fluid (CSF) sample from a patient and we were tasked with attempting to isolate the causative organism of our patient’s symptoms. From my CSF I was able to isolate Listeria monocytogenes. This is the same bacterium that was the causative agent of an outbreak in September to October of 2011 that infected 146 persons across 28 states and led to 30 deaths and one miscarriage. The mortality rate from listeric meningitis is fairly high ranging from 20% - 80%. So if only 20% of the people that get listeric meningitis survive how do you get it? First of all not everyone exposed to the bacteria will get listeric meningitis. The infectious dose is not known but it is known that neonates, elderly, pregnant women and immunocompromised individuals are at the highest risk. People without those risk factors can be affected however it is rare. My patient was an elderly patient and this fits with meningitis since the elderly are at a higher risk for listeriosis. So you probably are thinking that you can just avoid cantaloupe and you will be ok. Listeria monocytogenes is widespread in the environment. It has been recovered from soil, water, vegetation animal products such as raw milk, cheese, poultry, and processed meats. The frequency of listeriosis according to a prospectively collected study by the CDC in 1987 showed 1600 cases of listeriosis with 415 deaths per year in the U.S. The outbreak of Listeria monocytogenes last fall was tracked back to cantaloupes from Jensen Farms in the southeast of Colorodo. This was actually the first listeriosis outbreak associated with a whole fruit or vegetable. Factors that the FDA list as possible contributing factors included:

Growing Environment:

·         Low level sporadic Listeria monocytogenes in the agricultural environment and incoming cantaloupe may have contributed to the introduction of the pathogen into the packing facility.

Packing Facility and cold Storage:

·         A truck used to haul culled cantaloupe to a cattle operation was parked adjacent to the packing facility and could have introduced contamination into the facility;

·         Facility design allowed for the pooling of water on the packing facility floor adjacent to equipment and employee walkway access to grading stations;

·         The packing facility floor was constructed in a manner that was not easily cleanable;

·         The packing equipment was not easily cleaned and sanitized;

·         The washing and drying equipment used for cantaloupe packing was previously used for postharvest handling of another raw agricultural commodity; and

·         There was no pre-cooling step to remove field heat from the cantaloupes before cold storage.

The FDA made recommendations for prevention of Listeria monocytogenes based on their findings and they included the following:

·         Assess produce facility and equipment design to ensure adequately cleanable surfaces and eliminate opportunities for introduction, growth, and spread of Listeria monocytogenes and other pathogens. 

·         Assess and minimize opportunities for introduction of Listeria monocytogenes and other pathogens in packing facilities. 

·         Implement cleaning and sanitizing procedures.

·         Verify the efficacy of cleaning and sanitizing procedures.

·         Periodically evaluate the processes and equipment used in packing facilities to assure they do not contribute to fresh produce contamination. 

 Let me know if you have additional questions. You can also find additional information about Listeria monocytogenes or the the outbreak previously discussed at: http://www.cdc.gov/listeria/

Welcome

This first post will just be a little information about me and the purpose of this blog. My name is Jared Swiney. I received my bachelor’s degree from Auburn University in Biomedical Sciences in 2005. I have been married since 2006 and have a 2 year old daughter. I have about 12 years’ experience in the pharmacy industry where I have performed several roles in participant services, client services, training, and quality. I am also a lean six sigma green belt. I am currently a graduate student at the University of Alabama at Birmingham studying Clinical Laboratory Sciences. This summer I am taking CLS 538 Infectious diseases. For this class my graduate assignment is to write this blog. Twice per week I will post in this blog. The first post for each week will be information regarding a topic covered in class that week and the second post will be in regards to my graduate topic which is Hepatitis C Virus. Thanks for reading and I hope you enjoy my posts.