The Major Players
One of the biggest challenges with SIBO is that many bacteria that cause this condition are “normal” residents of our intestines. Bacteria such as Clostridium, E Coli or certain Streptococcus species are actually thought to be some of the most common contributors to SIBO, but because of impaired motility and other contributing factors mentioned above, these otherwise “healthy” bacteria are found to overgrow in the small intestine, resulting in SIBO.
Table 1. Major Players associated with hydrogen based SIBO
- Escherichia coli
- Klebsiella pneumoniae
Although aspiration of the small intestine, which involves a sample collection of fluid for cuture and analysis, is the only true determinant of what bacterial growth can be isolated to this part of the gut, this method of testing also has it’s problems.
Aspiration involves the use of a gastroscope, which is a device that gastrointestinal specialists use to visually, surgically and environmentally asses the esophagus, stomach, small intestine and colon. Although gastroscopy is fairly critical in some forms of gastrointestinal disease the first major problem that comes to mind is the hygienic challenges that a gastroscope has.
Certain chemicals used to clean the gastroscope are not actually cleaning agents but agents that are meant to damage the bacterial proteins through what is called crosslinking. This procedure is thought to be used so that the gastroscope can not contaminate the next patient. The problem with agents like glutaraldehyde is that it is not 100% effective and can actually accidentally preserve bacterial contaminates in the scope which has the potential to contaminate future patients but also aspiration samples.
Further, and even more concerning for accuracy is that many of the bacteria involved in SIBO are not able to be effectively cultured, or grown in a lab, which makes determining there presence also very difficult.
Another method of detection, although not as direct as aspiration, is 16s ribosomal subunit sequencing. Although this method of testing also has it’s problems, at least it is non-invasive, in that a stool test can be used to measure different bacterial populations in the gut. Obviously with a stool test, we are not only looking at the small intestinal bacteria, but also the large intestinal bacterial populations. None-the-less the very problem with 16s ribosomal subunit testing can also be helpful in this situation.
Stool testing with 16s ribosomal subunit polymerize chain reaction testing preferentially and incorrectly counts the bacterial cells that are actively and rapidly dividing, so when we see a culprit that could cause SIBO in a rapid division sequence it becomes a question of … if it looks like a duck, quacks like a duck and walks like a duck, then its likely a duck.
Stool testing for 16s ribosomal subunits is by no means ideal, but it can be invaluable for that hard to treat SIBO case. This testing can provide a more specific and sensitive approach to treatment, without just using the same old drugs or herbs. This testing has also allowed me, in some cases of SIBO, to treat the patient using nothing but special probiotics!
After the next 2 sessions on methogens and hydrogen sulphide SIBO we can look at specific treatment options for the major bacterial causes of SIBO. This is where things get functional!