[Clinical characteristics of 11 patients with Vibrio vulnificus infection and the establishment of a rapid diagnosis procedure for this disease].

Objective: To analyze the clinical characteristics of patients with Vibrio vulnificus infection, share diagnosis and treatment experience, and establish a rapid diagnosis procedure for this disease. Methods: This study was a retrospective case series study. From January 2009 to November 2022, 11 patients with Vibrio vulnificus infection who met the inclusion criteria were admitted to the Department of Burns and Wound Repair of Guangdong Provincial People's Hospital Affiliated to Southern Medical University. The gender, age, time of onset of illness, time of admission, time of diagnosis, route of infection, underlying diseases, affected limbs, clinical manifestations and signs on admission, white blood cell count, hemoglobin, platelet count, C-reactive protein (CRP), alanine transaminase (ALT), aspartate transaminase (AST), creatinine, procalcitonin, albumin, N-terminal pro-B-type natriuretic peptide (NT-proBNP), and blood sodium levels on admission, culture results and metagenomic next-generation sequencing (mNGS) results of pathogenic bacteria and the Vibrio vulnificus drug susceptibility test results during hospitalization, treatment methods, length of hospital stay, and outcomes of all patients were recorded. Comparative analysis was conducted on the admission time and diagnosis time of patients with and without a history of exposure to seawater/marine products, as well as the fatality ratio and amputation of limbs/digits ratio of patients with and without early adequate antibiotic treatment. For the survived patients with hand involvement, the hand function was assessed using Brunnstrom staging at the last follow-up. Based on patients' clinical characteristics and treatment conditions, a rapid diagnosis procedure for Vibrio vulnificus infection was established. Results: There were 7 males and 4 females among the patients, aged (56±17) years. Most of the patients developed symptoms in summer and autumn. The admission time was 3.00 (1.00, 4.00) d after the onset of illness, and the diagnosis time was 4.00 (2.00, 8.00) d after the onset of illness. There were 7 and 4 patients with and without a history of contact with seawater/marine products, respectively, and the admission time of these two types of patients was similar (P>0.05). The diagnosis time of patients with a history of contact with seawater/marine products was 2.00 (2.00, 5.00) d after the onset of illness, which was significantly shorter than 9.00 (4.25, 13.00) d after the onset of illness for patients without a history of contact with seawater/marine products (Z=-2.01, P<0.05). Totally 10 patients had underlying diseases. The affected limbs were right-hand in 8 cases, left-hand in 1 case, and lower limb in 2 cases. On admission, a total of 9 patients had fever; 11 patients had pain at the infected site, and redness and swelling of the affected limb, and 9 patients each had ecchymosis/necrosis and blisters/blood blisters; 6 patients suffered from shock, and 2 patients developed multiple organ dysfunction syndrome. On admission, there were 8 patients with abnormal white blood cell count, hemoglobin, and albumin levels, 10 patients with abnormal CRP, procalcitonin, and NT-proBNP levels, 5 patients with abnormal creatinine and blood sodium levels, and fewer patients with abnormal platelet count, ALT, and AST levels. During hospitalization, 4 of the 11 wound tissue/exudation samples had positive pathogenic bacterial culture results, and the result reporting time was 5.00 (5.00, 5.00) d; 4 of the 9 blood specimens had positive pathogenic bacterial culture results, and the result reporting time was 3.50 (1.25, 5.00) d; the mNGS results of 7 wound tissue/exudation or blood samples were all positive, and the result reporting time was 1.00 (1.00, 2.00) d. The three strains of Vibrio vulnificus detected were sensitive to 10 commonly used clinical antibiotics, including ciprofloxacin, levofloxacin, and amikacin, etc. A total of 10 patients received surgical treatment, 4 of whom had amputation of limbs/digits; all patients received anti-infection treatment. The length of hospital stay of 11 patients was (26±11) d, of whom 9 patients were cured and 2 patients died. Compared with that of the 6 patients who did not receive early adequate antibiotic treatment, the 5 patients who received early adequate antibiotic treatment had no significant changes in the fatality ratio or amputation of limbs/digits ratio (P>0.05). In 3 months to 2 years after surgery, the hand function of 8 patients was assessed, with results showing 4 cases of disabled hands, 2 cases of incompletely disabled hands, and 2 cases of recovered hands. When a patient had clinical symptoms of limb redness and swelling and a history of contact with seawater/marine products or a pre-examination triage RiCH score of Vibrio vulnificus sepsis ≥1, the etiological testing should be initiated immediately to quickly diagnose Vibrio vulnificus infection. Conclusions: Vibrio vulnificus infection occurs most frequently in summer and autumn, with clinical manifestations and laboratory test results showing obvious infection characteristics, and may be accompanied by damage to multiple organ functions. Both the fatality and disability ratios are high and have a great impact on the function of the affected limbs. Early diagnosis is difficult and treatment is easily delayed, but mNGS could facilitate rapid detection. For patients with red and swollen limbs accompanied by a history of contact with seawater/marine products or with a pre-examination triage RiCH score of Vibrio vulnificus sepsis ≥1, the etiological testing should be initiated immediately to quickly diagnose Vibrio vulnificus infection.

[Effects of allogeneic bone marrow mesenchymal stem cells on polarization of peritoneal macrophages in rats with sepsis].

Objective: To explore the effects of allogeneic bone marrow mesenchymal stem cells (BMSCs) on polarization of peritoneal macrophages isolated from rats with sepsis induced by endotoxin/lipopolysaccharide (LPS). Methods: (1) BMSCs were isolated, cultured and purified from 5 SD rats with whole bone marrow adherent method. The third passage of cells were collected for morphologic observation, detection of expressions of stem cell surface markers CD29, CD44, CD45, and CD90 with flow cytometer, and identification of osteogenic and adipogenic differentiation. (2) Another 45 SD rats were divided into sham injury group (SI, n=5), LPS control group (LC, n=20), and BMSCs-treated group (BT, n=20) according to the random number table. Rats in groups LC and BT were injected with LPS (5 mg/kg) via tail vein to induce sepsis; rats in group SI were injected with the same amount of normal saline to simulate the damage. At post injury hour (PIH) 1, rats in group BT were given 1 mL BMSCs (2×10(6)/mL) via tail vein injection; rats in another two groups were injected with equal volume of phosphate buffer saline. Five rats in group SI at PIH 24 and in groups LC and BT at PIH 6, 12, 24, and 48 were sacrificed to harvest lung tissue for pathological observation with HE staining. In addition, rats in group SI at PIH 24 and in groups LC and BT at PIH 24 and 48 were simultaneously performed with intraperitoneal injection of low-glucose DMEM. Then peritoneal fluid was harvested to culture peritoneal macrophages. Flow cytometer was used to assess the positive expression of cell makers of macrophages including CD68 (making gate), CD11c, and CD206 in group SI at PIH 24 and in groups LC and BT at PIH 24 and 48. Data were processed with one-way analysis of variance and LSD test. Results: (1) The third passage of cells showed uniform fiber-like shape similar to fibroblasts. These cells showed positive expressions of CD29, CD44, CD90 and weak positive expression of CD45. They were able to differentiate into osteoblasts and adipocytes. These cells were identified as BMSCs. (2) At PIH 24, the structure of pulmonary alveoli of rats in group SI was clear and complete with no congestion or inflammatory cell infiltration. At PIH 6, the structure of pulmonary alveoli of rats in groups LC and BT was clear with a small amount of inflammatory cell infiltration, slight congestion and pulmonary interstitial thickening. At PIH 12, the inflammatory responses in lung tissue of rats in group LC were more severe than those in group BT with a large amount of inflammatory cell infiltration, serious congestion, and obvious pulmonary interstitial thickening. The pathological results of rats in group BT at PIH 12 was consistent with the results at PIH 6. At PIH 24, the pathological results of rats in groups LC and BT were similar to the results at PIH 12. At PIH 48, the structure of pulmonary alveoli tissue of rats in group LC was still severely disrupted, with a large number of inflammatory cell infiltration and congestion in lung tissue, but pulmonary interstitial thickening was slightly alleviated than before. The condition of rats in group BT nearly recovered to that in group SI. (3) At PIH 24, the positive expression rate of CD11c in peritoneal macrophages of rats in group LC [(83±10)%] was close to that in group BT [(87±7)%, P>0.05], and they were both significantly higher than the rate in group SI [(55±12)%, with P values below 0.01]. The positive expression rate of CD11c in peritoneal macrophages of rats in group LC [(59±11)%] at PIH 48 was close to that in group SI at PIH 24 (P>0.05), and they were both significantly higher than the rate in group BT [(20±11)%] at PIH 48 (with P values below 0.01). At PIH 24, the positive expression percentages of CD206 in peritoneal macrophages of rats were similar among the three groups (with P values above 0.05). The positive expression percentage of CD206 in peritoneal macrophages of rats in group SI at PIH 24 was close to that in group BT at PIH 48 (P>0.05), and they were both significantly lower than the percentage in group LC at PIH 48 (with P values below 0.01). Conclusions: BMSCs can reduce the pathological inflammatory responses in the lung of rats with sepsis and inhibit peritoneal macrophages from polarizing into M1 phenotype, whereas they can not promote macrophages to polarize into M2 phenotype.