Tag Archive for: bacteria

What’s so interesting about microbiology? Microorganisms were here before man walked the Earth, and they’ll be here after we’re gone. Actually, you would find it difficult to survive without them. Some bacteria, called commensals, live in and on our bodies to our benefit, protecting  us from invading pathogens (disease causing germs), and they produce vitamins.

On the opposite end of the spectrum are the bad bugs. They’re responsible for more deaths than cancer, heart attacks, and war. They can disfigure, eat flesh, paralyze, or just make you feel so bad you wish you were dead.

There are four major types of microorganisms: bacteria, viruses, fungi, and parasites. They can cause damage directly, or they can release toxins that do the dirty work for them.

CDC image

CDC image



CDC image

CDC image

So, how can your villains use microorganisms to kill? First they’ll need a fundamental knowledge of microbiology, such as information that’s taught in a basic college course. Next, the bad guy will need a source of bacteria. Microbiology labs all over the world contain bugs of all types.

Labs of this type are secure so a little B & E would be in order. Or, maybe your villain has a connection with a person who has control of the bug of interest. If so, the evil-doer could make what’s known in the trade as a V.I.P. trip. He’d fly to the friend’s lab, place the bug in a plastic vial, hide the vial in his pocket (V.I.P.), and get back on the plane for the trip home.

Once the potential killer has the bug, he has to keep it alive and reproducing. Bacteria are grown on agar plates (food for bugs) in an incubator. In general, bacteria double in number every 20 minutes. So, if you start with just a few bugs, let’s say 10, and allow them to grow overnight…well, you do the math. Once the bad guy has enough of the bug, then it’s time to deliver it to the intended victim.

Picking up bacteria from agar plate. The brownish-red material is the agar. The grayish coloring at the top of the agar is E.coli bacteria.

Now for a true story. It wasn’t murder, just an unfortunate accident that involved a woman, some green beans, and a home canning jar. Canning jars have lids designed to exhibit a slight indentation in their centers when food is fresh. If the indentation inverts (pops up), the vegetables may be contaminated, and should be discarded.

A woman was preparing dinner for her family and decided to serve some of her home-canned green beans that evening. She picked up a jar of beans, but thought the pop-up didn’t look quite right. So, to satisfy her curiosity, she opened the jar, touched her finger to the bean juice, and tasted it. It tasted fine to her, so she cooked the beans and served the steaming hot dish to her family. The next day the woman died, but her family survived. The beans contained botulism toxin produced by the bacteria, Clostridium botulinum. C. botulinum lives naturally in the soil.

Botulism toxin is one of the most powerful neurotoxins known to man. About 10 ounces could kill everyone on Earth. It works by paralyzing its victim. Why didn’t the other members of the family die? The toxin is inactivated by heat.

Dr. Denene Lofland received her PhD degree in pathology from the Medical College of Virginia, and she’s a trained clinical microbiologist. She has served as the Director of Clinical Laboratory Sciences at Wright State University, and has worked in biotech/drug research and development for many years.

As a biotech director she and her team developed and received FDA approvals of the drugs gemifloxacin (Factive), an antibiotic for the treatment of bacterial pneumonia, and Cayston, an inhaled antibiotic for cystic fibrosis. Both medications have been prescribed by physicians worldwide.

As Manager of Operations for a company that specialized in high-level anti-bioterrorism research and development, Denene supervised several projects,  including government-sponsored research for the Defense Advanced Research Project Agency (DARPA), which required her to maintain a secret security clearance.

Denene has published numerous articles in scientific and other peer-reviewed journals. She contributed to the thirteenth edition of Bailey and Scott’s Diagnostic Microbiology, and she’s a contributing author of the Textbook of Diagnostic Microbiology (Elsevier 2022).

She was recently named a Fellow of the Association of Clinical Scientists, an elite association of top scientists from around the world that includes pathologists, clinical chemists, molecular and cell biologists, microbiologists, immunologists, hematologists, cytogeneticists, toxicologists, pharmacokineticists, clinicians, cancer researchers and other doctoral scientists who are experts in laboratory methods for the elucidation, diagnosis, and treatment of human diseases.

Denene currently serves as Microbiology and Immunology Thread Director at Drexel University College of Medicine.

During their crime-solving duties homicide investigators hear and see a lot of details—gunfire, fleeing suspects, yelling and screaming, pleas for help, blood and viscera, and even the sounds of their own hearts as they frantically beat against the inside walls of their chests.

But once the dust settles around the crime scene, and all is quiet, it’s time for detectives to focus their attention on the murder victim and what they have to “say.” Believe me, they have a quite a story to tell.

Bacteria Beach

Before we take our walk on Bacteria Beach, let’s first join an enthusiastic group of writers for a very brief introduction of the topic du jour. Please click the play button.

Now, on with Decomposition!

Putrefaction is the destruction of the soft tissue caused by two things, bacteria and enzymes. As the bacteria and enzymes do their jobs the body immediately begins to discolor and transform into liquids and gases. The odd thing about the bacteria that destroys tissue at death is that much of it has been living in the respiratory and intestinal tracts all along.  Of course, if the deceased had contracted a bacterial infection prior to death, that bacteria, such as septicemia (blood poisoning), would aid in increasing the body’s decomposition.

Temperature plays an important part in decomposition. 70 degrees to 100 degrees F is the optimal range for bacteria and enzymes to do what they do best, while lower temperatures slow the process. Therefore, and obviously, a body will decompose faster during the sweltering days of summertime.


A blood-filled circulatory system acts as a super-highway for those organisms that destroy the body after death. Without blood the process of putrefaction is slowed.

  • A murder victim whose body bled out will decompose at a slower rate than someone who died of natural causes.
  • Bodies adorned in thick, heavy clothing (the material retains heat) decompose more rapidly than the norm. Electric blankets also speed up decomposition.

Bodies decompose faster during the sweltering days of summertime

A body that’s buried in warm soil may decompose faster than one that’s buried during the dead of winter. The type of soil that surrounds the body also has an effect on the rate of decomposition. For example, the soil in North Carolina is normally a reddish type of clay. The density of that clay can greatly retard the decomposition process because it reduces the circulation of air that’s found in a less dense, more sandy-type of earth.

Adult bodies buried in a well drained soil will become skeletonized in approximately 10 years. A child’s body in about five years.

People who were overweight at the time of their deaths decompose faster than skinny people. People who suffered from excessive fluid build-up decompose faster than those who were dehydrated. And people with massive infections and congestive heart failure will also decompose at a more rapid rate than those without those conditions.

The rule of thumb for the decomposition of a body is that, at the same temperature, 8 weeks in well-drained soil equals two weeks in the water, or one week exposed to the air.

Now, hold on to your breakfast …

The first sign of decomposition under average conditions is a greenish discoloration of the skin at the abdomen. This is apparent at 36-72 hours.

Next – Small vessels in the skin become visible (marbling).

Followed by, glistening skin, skin slippage, purplish skin, blisters, distended abdomen (after one week – caused by gases), blood-stained fluid oozing from body openings (nose, mouth, etc.), swelling of tissue and the presence of foul gaseous odor, greenish-purple face, swollen eyelids and pouting lips, swollen face, protruding tongue, hair pulls out easily, fingernails come off easily, skin from hands pulls off (gloving), body swells and appears greatly obese.

Internally, the body is decomposing and breaking down. The heart has become flabby and soft. The liver has honeycombed, and the kidneys are like wet sponges. The brain is nearly liquid, and the lungs may be a bit brittle.

Okay, I’m done for now. But before you go, here’s a reminder, from me to you …

For ten long years, David Foran, a molecular geneticist and forensic scientist at Michigan State University, has worked to turn the bacteria found in soil into permissible evidence in criminal cases. It was a former student, though, a microbiology major, who first came up with the idea.

This could be an earth-shattering breakthrough since the goal of the research is to establish an objective standard, backed by solid statistical data, that could link soil found on a particular item to soil from a crime crime. The technique uses the DNA of bacteria from a sample, say on a digging implement—shovel, pick, spade, etc., to that found in soil from the scene of the crime. Of course, numerous factors could alter/influence each sample—temperature, foreign substances such as blood, sweat, chemicals, etc.—and each of those would be studied, classified, and categorized to allow for inclusion or exclusion (sample matches a known soil and substance, or not).

Once the research is perfected courts may then allow the testing method and soon after crime labs would then add it to their crime-solving toolboxes.

Daubert, Frye, and Using Bacteria Found in Soil to Solve Criminal Cases

So how does a procedure become suitable for courtroom and legal proceedings? What are the rules regarding who may testify as an expert witness?

Narcotics investigations

I was once put through the ringer in a courtroom before being declared, by a superior court judge, as an expert witness on narcotics and how they’re made, packaged, and sold.

This was during a time when my major focus as an investigator was on major drug cases.

Typically, judges make the final decision as to who or what is allowed in their courtrooms, and that includes which evidence is admissible and who may or may not testify as an expert witness. And, they normally rely on either the Daubert standard or Frye, both precedent setting case. Some states follow Daubert. Others follow Frye. And a small handful use either.

Daubert v. Merrell Dow Pharmaceuticals 


Frye v. United States, 293 F. 1013 (D.C. Cir. 1923)


Daubert is by far the most widely used standard in courtrooms across the country, and the rules according to Daubert are:

Per Cornell Law School (law.cornell.edu) – “Standard used by a trial judge to make a preliminary assessment of whether an expert’s scientific testimony is based on reasoning or methodology that is scientifically valid and can properly be applied to the facts at issue. Under this standard, the factors that may be considered in determining whether the methodology is valid are: (1) whether the theory or technique in question can be and has been tested; (2) whether it has been subjected to peer review and publication; (3) its known or potential error rate; (4) the existence and maintenance of standards controlling its operation; and (5) whether it has attracted widespread acceptance within a relevant scientific community. See Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993). The Daubert standard is the test currently used in the federal courts and some state courts.  In the federal courts, it replaced the Frye standard.”

Now, back to the soil sampling. Here’s a nugget for your research files. I once investigated a murder where I collected soil samples, among many, many other pieces of evidence, hoping to find the needle in the haystack. Without a bit of good luck this case could’ve quickly gone cold.

Fortunately, scientists matched a single, unusual plant seed I found and collected at the crime scene to one found in dried mud stuck to the accelerator pedal of the killer’s car (I also collected this sample). The plant grew in only one location in the area, at a particular spot near a river—the very spot where the body was found. I had a hunch and it paid off.

That one tiny seed was the icing on the cake in this case. I also matched tire tracks and I eventually obtained a confession from the suspect.

Here are the details of the sad case case (above) told in a brief writeup you might find interesting. A Dead Woman Crying: Murder in the Rain.