Browsing by Subject "C. pneumoniae"
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(2021)The life cycle of Chlamydia pneumoniae is a biphasic developmental cycle, as a obligate intracellular bacterium, it forms various morphological forms, including elementary bodies, reticulate bodies and aberrant bodies belonging to a persistent form. Due to the bacterial life cycle and the fact that chronication of C. pneumoniae infection and formation of persistent infection as well as pathogenesis is a complex problem involving multiple signaling pathways and affecting several different cells, it is useful to seek medication to influence infection from different stages of the bacterial life cycle. There are several different factors that induce persistence and thus models of persistence. Although the detection of aberrant RBs and thus aberrant bodies in C. pneumoniae infected tissues does not provide complete certainty about chronic infection, the bacterium has been linked to chronic health problems such as atherosclerotic cardiovascular disease and asthma. The aim of the study was to develop a persistence model induced by beta-lactam antibiotics, amoxicillin and penicillin G, in A549 cells by monitoring the size, shape, and number of inclusions using the IPA method and the immunofluorescence staining method for infection. In addition, the antibiotic sensitizing effect of three compounds on pulmonary chlamydial infection was studied. This effect was monitored by examining the recovery of persistent infection and by monitoring the protective effect of the compounds on beta-lactam-induced persistence. The work succeeded in finding an infection model that is well suited for studying beta-lactam persistence. Due to treatment recommendations, pulmonary chlamydial infections are practically treated with beta-lactam antibiotics. Based on the methods used, it was found that amoxicillin concentrations of 10 and 25 µg/ml and penicillin G concentrations of 100 U/ml and 250 U/ml were sufficiently effective to transfer bacteria to a state of persistence. It was found that the amoxicillin persistence model is reversible based on the increase in the size of the inclusions, especially at 25 µg/ml and quantitatively at 10 µg/ml. It was concluded that amoxicillin at a concentration of 10 µg/ml is sufficient to induce persistence in a beta-lactam antibiotic-induced persistence model. Further quantitative studies on the persistence model are needed, such as quantitative PCR based on the OmpA gene to determine more accurate dose-response relationships. Glutathione levels should also be monitored in the persistence model.
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(2023)Chlamydia pneumoniae is an intracellular Gram-negative bacterium, that can cause respiratory infections. Infections are typically mild or asymptomatic, but it can also lead to more severe infections, for example, pneumonia. Severe infections might need antibiotic treatment. When the bacteria are exposed to stressful conditions, they can change to a chronic, persistent form. Amoxicillin and penicillin are known to transform bacterium into persistent forms. Antibiotics are not effective for persistent infection very often. Amoxicillin is the recommended treatment for pneumonia in Finland and worldwide, which is problematic from the perspective of C. pneumoniae. That is why there is a need for effective treatment for persistent C. pneumoniae infection. Probiotics and their by-products short chain fatty acids (SCFAs) are known to have beneficial effects on human health. Based on the current knowledge, SCFAs and other probiotic by-products are known to inhibit pathogen bacterial growth. Thus, SCFAs could have a potential effect on the treatment of C. pneumoniae infection. The aim of this work is to study the impact of SCFAs, acetate, propionate, and butyrate on C. pneumoniae infection and its antibiotic susceptibility. To study the impact of acetate, propionate and butyrate on C. pneumoniae infection and its antibiotic susceptibility, three different infection models were used: productive C. pneumoniae infection model with A549 cells, amoxicillin-induced persistent infection model with A549 cells, and persistent infection model with THP1 cells. Bacterial growth was followed with immunofluorescence and the number of the bacterial genome was studied with quantitative polymerase chain reaction (qPCR). The studied SCFAs did not have a significant impact on productive C. pneumoniae infection. With amoxicillin- induced persistent infection, the results were varying. For example, sodium acetate, and propionate showed some increase in bacterial growth on the first infection, but with sodium butyrate, there were not any impact. The only SCFA that decreased the bacterial growth in the persistent infection model with THP1 cells was sodium butyrate (200 μM). The same treatment also decreased the number of bacterial genomes with qPCR in the same infection model. In addition, the same condition increased the antibiotic susceptibility of persistent C. pneumoniae to azithromycin in THP1 cells. In conclusion, the studied SCFAs seemed to have more impact on C. pneumoniae infection with human immune cells compared to human lung epithelial cells. Based on this study, sodium butyrate could have positive impacts against persistent C. pneumoniae infection. Nevertheless, further studies of the impact of sodium butyrate on persistent C. pneumoniae infection are needed.
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