Peptidoglycan Sensing Prevents Quiescence and Promotes Quorum-Independent Colony Growth of Uropathogenic Escherichia coli.

Uropathogenic Escherichia coli (UPEC) is the leading cause of human urinary tract infections (UTIs), and many patients experience recurrent infection after successful antibiotic treatment. The source of recurrent infections may be persistent bacterial reservoirs in vivo that are in a quiescent state and thus are not susceptible to antibiotics. Here, we show that multiple UPEC strains require a quorum to proliferate in vitro with glucose as the carbon source. At low cell density, the bacteria remain viable but enter a quiescent, nonproliferative state. Of the clinical UPEC isolates tested to date, 35% (51/145) enter this quiescent state, including isolates from the recently emerged, multidrug-resistant pandemic lineage ST131 (i.e., strain JJ1886) and isolates from the classic endemic lineage ST73 (i.e., strain CFT073). Moreover, quorum-dependent UPEC quiescence is prevented and reversed by small-molecule proliferants that stimulate colony formation. These proliferation cues include d-amino acid-containing peptidoglycan (PG) tetra- and pentapeptides, as well as high local concentrations of l-lysine and l-methionine. Peptidoglycan fragments originate from the peptidoglycan layer that supports the bacterial cell wall but are released as bacteria grow. These fragments are detected by a variety of organisms, including human cells, other diverse bacteria, and, as we show here for the first time, UPEC. Together, these results show that for UPEC, (i) sensing of PG stem peptide and uptake of l-lysine modulate the quorum-regulated decision to proliferate and (ii) quiescence can be prevented by both intra- and interspecies PG peptide signaling.IMPORTANCE Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections (UTIs). During pathogenesis, UPEC cells adhere to and infiltrate bladder epithelial cells, where they may form intracellular bacterial communities (IBCs) or enter a nongrowing or slowly growing quiescent state. Here, we show in vitro that UPEC strains at low population density enter a reversible, quiescent state by halting division. Quiescent cells resume proliferation in response to sensing a quorum and detecting external signals, or cues, including peptidoglycan tetra- and pentapeptides.

[Malignant proliferating trichilemmal cyst of the scalp: A case report]. / Kyste trichilemmal proliférant malin du scalp : une nouvelle observation.

BACKGROUND: Proliferating trichilemmal cyst (PTC) is a rare adnexal tumor, generally benign, primarily sitting on the scalp of elderly women. About fifty cases are reported in the literature. Herein, we describe another one particularly aggressive. OBSERVATION: A 70-year-old woman had been showing an increase in the size of an occipital cyst for 6years. A cephalic scan and wide surgical excision had confirmed the diagnosis of a malignant PTC. Four months later, the tumor recurred with regional metastases and intracerebral invasion. DISCUSSION: Through our case and based on the literature analyzing, we discuss the nosology of PTC and its clinical and histological distinctive elements. CONCLUSION: Large studies are needed to better understand the specificities of PTC, specially malignant form, but it remains difficult because of its rarity.

The Effects of Hyperosmolar Dextrose and Autologous Serum Injection in the Experimental Articular Defect of Rabbit

OBJECTIVE: Although the clinical effects of prolotherapy on osteoarthritis has been reported, there have been few previous studies showing the effects as a proliferant on articular cartilage. Also the autologous blood has been reported to used as a growth factor stimulant recently, we were trying to use dextrose and autologous serum for tissue regeneration respectively and evaluated the proliferative effect of autologous serum comparing with that of dextrose. METHOD: Twenty four rabbits were used for this study. The rabbits were divided into three groups. Group A did not get any special treatment. Group B was treated with 10% dextrose and group C with autologous serum. Six weeks later, gross appearance and histologic findings were evaluated. RESULTS: After sacrifice, the gross inspection of the knee joints revealed that group B and C were filled with the translucent tissue in defective cartilage. Group A still had defective cartilage. Histologic evaluation revealed increase of cellularity in the defect of the injected specimens when compared with the control. There was no morphological difference between group B and C. CONCLUSION: The repair process of the articular cartilage defects using dextrose and autologous serum were shown to be more effective than that of control group.

The Response of the Injured Articular Cartilage of Rabbit Knee after Injection of Autologous Blood

OBJECTIVE: To evaluate the effects of proliferant by injecting blood into the articular cartilage defect. METHOD: The patella of rabbits were dislocated laterally and 2 mm circular and 2 mm depth full-thickness defect was made in the articular cartilage. We injected 0.2 cc autologous blood to the right defect and normal saline to the left one at 1 week after operation for six times with a 1 week interval. After injection for six weeks, the articular cartilage defect were obtained and stained with H-E and S-100. RESULTS: The surface of the saline-injected group was easily distinguishable from the surrounding articular cartilage. But the blood-injected group had similar appearance to the surrounding cartilage, with the margin of the defect barely discerptible. Strong S-100 stained immune cartilage cells were observed in the blood-injected group. CONCLUSION: The repairing process of the injured articular cartilage using autologous blood was shown to be much better than that of saline-injected group although the observation period was short and the number of animal was small. So we found that autologous blood effectively repaired osteochondral defects.

Comparison of Histological Changes in Accordance with the Level of Dextrose-Concentration in Experimental Prolotherapy Model

OBJECTIVE: Comparing histological changes according to the level of dextrose-concentration of proliferant under the same osmolarity on Achilles tendon of rat. METHOD: One millimeter of three proliferant solutions (20% dextrose water-group A, 5% dextrose water mixed with NaCl-group B, NaCl solution-group C) with the same osmolarity (1, 110 mOsm) was injected around the right Achilles tendon of each rat, whereas the left was not injected to be used as control. After six weeks of injection, the injected tendons and controls were obtained. The transverse diameter of gross specimen, the count of fibroblasts on light microscope, and the findings of cross-sectional analysis using electron microscope were compared. RESULTS: Overall, transverse diameter and the count of fibroblasts increased in the injected specimens compared to controls, however, their significant differences were demonstrated only for the two groups injected with dextrose containing solutions (p<0.05). However, A and B groups did not show significant differences in all parameters investigated. On electron micrograph, fibril diameters of solution-injected tendon consisted of either extremely large or small sizes with the limited intermediate sizes. CONCLUSION: Although high osmolar solution could increase the transverse diameter and fibroblast counts, however, dextrose-containing solution was much more effective as a proliferant solution.