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Human papillomavirus (HPV) persistent infection is the necessary but not sufficient cause of cervical cancer. Other co-factors are required to induce cell transformation that will evolve to malignant cervical cancer. These co-factors include physical elements, other sexually transmitted infections, and immune response. Chlamydia trachomatis the most common bacterial sexually transmitted infection is often asymptomatic but causes various syndromes such as cervicitis, endometritis, pelvic inflammatory disease, and infertility. It is established that this bacterium is involved in cell proliferation process and inhibit apoptosis. Furthermore, C. trachomatis may induce chronic inflammation, interfere with immune response by decreasing the number of antigen presenting cells, and reduce the cell-mediated immunity allowing the persistence of HPV. However, it is unclear whether this bacterium plays a particular role in cervical cancer induction. We therefore aimed at enlightening the actual knowledge about the relationship between C. trachomatis and cervical cancer or precursor lesions through a systematic literature review. We summarized and analyzed the epidemiological data on C. trachomatis and its co-infection with HPV and their association to cervical cancer.

This paper studies the phosphate uptake by pure cultures of Aeromonas hydrophila, Klebsiella oxytoca, Agrobacterium tumefaciens, and Aquaspirillum dispar in the presence of both nitrate and oxygen. It is shown that species were able to respire both electron acceptors for phosphate accumulation. A. tumefaciens and A. dispar accumulated overall phosphate both in oxic and anoxic culture conditions, whereas A. hydrophila and K. oxytoca eliminated overall phosphate only in oxic conditions. A. dispar was able to remove phosphate by reducing oxygen and nitrate simultaneously with the production of dinitrogen gas. The anoxic denitrification observed in the cultures of adapted and nonadapted cells to nitrate showed that only A. dispar have a denitrification rate superior when the cells were adapted to nitrate.

In this study, phosphate-accumulating bacteria achieved complete phosphate removal in two different systems: an anaerobic-anoxic sequencing batch reactor and an anaerobic-aerobic sequencing batch reactor. This result shows that phosphate-accumulating bacteria in the A2 SBR can use nitrate as terminal electron acceptor instead of oxygen. Phosphate-accumulating bacteria accumulated phosphate with a rates between 30 and 70 mg P/L/h in the A/O SBR and between 15 and 32 mg P/L/h in the A2 SBR. Twenty denitrifying isolates were screened from A2 SBR and nine from A/O SBR. Identification of these isolates by the Biolog system and the API 20 NE identification kit revealed that the most active denitrifiers in both SBRs reactors were species of Ochrobactrum, Pseudomonas, Corynebacterium, Agrobacterium, Aquaspirillum, Haemophilus, Xanthomonas, Aeromonas, and Shewanella. The most active phosphate accumulating and denitrifying bacteria were identified as Agrobacterium tumefaciens B, Aquaspirillum dispar, and Agrobacterium radiobacter. This study showed that the active phosphate accumulating-bacteria were also the most efficient denitrifying bacteria in both reactors.