Latococcus Lactis Case Study

Unit 1 Discussion
Does the Lactococcus lactis qualify as a probiotic? Lactococcus lactis is a specific Gram-positive bacteria that seems to be at the center of attention with regards to it's use as a probiotic(1). Although an argument can be made for or against the use of Lactococcus lactis in such a manner, I believe that it would not be effective and may not even qualify as probiotic in general. Gregor Reid defines probitotics as microorganisms that, when administered, confer a health benefit on the host. He also specifically mentions that the microorganisms must be live which is a key distinction(2). The host can benefit from probiotics in ways that help to facilitate and strengthen the gut microflora. As long as the microorganisms can
colonize and provide a positive benefit to the host, one may consider it's use. According to Dr.
Todar, Lactococcus does not normally colonize human tissues and differs from many other lactic acid bacteria(3). If Lactococcus lactis can not colonize on human tissue it may be unable to preform it's duties as a consistent gut microflora probiotic. Lactococcus lactis does have relatives that can withstand the temperature and pH of the human gut which might give us some insight as to what makes them different. This is one of the major reasons I believe that Lactococcus lactis does not qualify as a probiotic. A second major reason as to why I believe that Lactococcus lactis does not qualify as a probiotic is because lack of testing and evidence to support health claims. According to the National Center for Complementary and Integrative Health, many probiotics are sold as dietary supplements that do not require FDA approval before being marketed(4). The FDA has a rigorous approval plan for certain probiotics as well as prescription medication. If probiotics are not regulated it is quite possible to have marketed supplements that do not contain any health benefit whatsoever. Overall I believe that Lactococcus lactis does not qualify as a probiotic. The fact that it does not normally colonize in human tissue as well as the poor amount of testing and evidence used to support health claims are just a few
reasons.
Would the incorporation of L. lactis into the gut microflora be desirable? I believe that initially the incorporation of Lactococcus lactis into the gut microflora would not be desirable. As stated before, the bacteria can not colonize human tissue like it's relatives. If scientists can genetically modify Lactococcus lactis to colonize inside the human gut it may become desirable. Modified Lactococcus lactis produces a crystal protein (Cry) that is known to be lethal to roundworm parasites (5). This would be useful in attacking nematodes such as hookworms and whipworms that may colonize the human gut. On the opposite side of the argument, Reid states in his article that probioitics could work better if they had been grown in a media that resembles that of their natural environment(2). One may conclude that if scientists can mimic the microflora of the human gut and try and grow the bacteria before actually introducing it to the human gut it might help give Lactococcus lactis a head start. It may, so to speak, warm the bacteria up and help them get used to an environment they would be settling in. Although I do not believe that the incorporation of Lactococcus lactis into the gut microflora is desirable, genetically modifying the bacteria or helping to prepare them for the harsh environment that the human gut presents may change my thinking. If scientist can colonize the bacterium in the human gut and prove that it contributes positively to the microflora, Lactococcus lactis may become desirable and may act as a probiotic.
Many nematode species are beneficial in soil (they are used to control insect pests); can you foresee any issues with the use of such an engineered L.
lactis? The issue discussed with the use of an engineered Lactococcus lactis is that it can be lethal to the nematode parasites in the soil. The Lactococcus lactis produces a crystal protein that, when ingested, can cause death for the parasites. These Cry proteins have been used as crop insecticides in the past. Some of the nematode species are used to control insect pests as well. The introduction of Lactococcus lactis would no undoubtedly decrease the number of nematode species in the affected area. In turn, this would also lower the nematodes affect as a pest controller. If the nematode species already acts naturally to control insect pests, why introduce a modified bacteria that will only become a replacement? According to Durmaz et al. the goal is to introduce the Cry proteins into the human gut to prevent parasitic nematode infections(5). I believe that if the modified Lactococcus lactis can colonize the human gut, scientist should consider a secondary method of approach with regards to the oral delivery system used in the past. This would prevent the harmful effects on the nematode species when used as crop
insecticides. With further development and testing, scientists may lean towards using Lactococcus lactis as a probiotic in a dietary supplement form. This would keep the Cry proteins away from the nematode species that are beneficial in the soil but also, when ingested by humans, keep parasitic infections away from the gut.