Late-onset sepsis caused by Leclercia adecarboxylata in a preterm neonate: case report and literature review / 中华围产医学杂志

Objective:To summarize the clinical characteristics of neonatal late-onset sepsis (LOS) caused by Leclercia adecarboxylata, and provide evidence for its diagnosis and treatment. Methods:We report a case of Leclercia adecarboxylata induced LOS in a male preterm neonate diagnosed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) at the Affiliated Suzhou Hospital of Nanjing Medical University. Relavant literature was retrieved from Wanfang, VIP, CNKI, and PubMed databases up to April 2021, using terms including "neonate" "sepsis" and " Leclercia adecarboxylata". Results:The patient presented with dyspnea immediately after birth with gestational age of 34 +3 weeks and birth weight of 2 050 g. After admission at 14 min after birth, he was incubated at temperature of 33-35 ℃ and humidity of 50%-60% and received active treatment, consisting of nasal continuous positive airway pressure, tracheal intubation, intratracheal injection of pulmonary surfactant, invasive mechanical ventilation, and anti-infective treatment with piperacillin, cefoperazone/sulbactam, and meropenem. However, the patient developed LOS on day 11 of life and eventually died of disseminated intravascular coagulation and multiple organs failure despite volume expansion, anti-infective therapy, and respiratory support. The blood culture was positive for Gram-negative rod and confirmed as a multi-drug resistant strain of Leclercia adecarboxylata. Two cases of LOS caused by sensitive strain of Leclercia adecarboxylata in premature female infants were retrieved in the literature with atypical symptoms, of whom one was successfully treated and one died after active treatment. Conclusions:Leclercia adecarboxylata infection alone can lead to LOS in preterm infants without typical manifestations. MALDI-TOF MS is helpful for the diagnosis and rational application of antibiotics.

Clinical characteristics of retroperitoneal fibrosis:an analysis of 28 cases / 中华全科医师杂志

Clinical data of 28 patients diagnosed with retroperitoneal fibrosis (RPF) in Shanxi Bethune Hospital from September 2014 to September 2020 were retrospectively analyzed. There were 16 males and 12 female with a mean onset age of (56±11) years. The clinical manifestations were lumbago (16/28, 57.14%), abdominal pain (9/28, 32.14%) and back pain (8/28, 28.57%). Inflammatory indexes were elevated in 25 cases (89.29%), and 3 cases had renal insufficiency. Serum IgG4 was elevated in 3 cases (10.71%). Scheel imaging evaluation showed that proportion of type Ⅰ combined with type Ⅲ (abdominal aorta and/or iliac vascular involvement combined with unilateral or bilateral ureteral involvement) was the highest(50.00%, 14/28). followed by. Twenty-seven patients (96.43%) were treated with glucocorticoids and immunosuppressants; 14 patients (50.00%) underwent surgical intervention for ureteral obstruction or hydronephrosis; 6 patients (21.43%) relapsed during hormone withdrawal; 6 patients (21.43%) recovered from the disease and terminated medication; and 13 patients (46.43%) successfully removed the double J tube after lifting ureteral obstruction and hydronephrosis. It is suggested that RPF is more likely to occur in middle-aged and elderly men, with low back pain as the main clinical feature, and ureteral involvement as the main imaging feature. Glucocorticoid combined with immunosuppressive therapy is the conventional treatment. Surgical intervention can relieve acute obstruction and effectively improve the prognosis of patients.

A temperature-inducible Targetron system for efficient gene inactivation in Escherichia coli / 生物工程学报

To construct TeI3c/4c-based and temperature-inducible gene inactivation system (Thermotargetron) and to apply it to gene inactivation of mesophilic bacteria. The subunit of flagellum (fliC) and C4 dicarboxylate orotate:H⁺ symporter (dctA) genes were chosen as targets in the genome of Escherichia coli HMS174 (DE3) strain. According to recognition roles of TeI3c/4c intron, the fliC489a, fliC828s, fliC1038s and dctA2a sites were chosen as target sites. Gene-targeting plasmids were constructed based on pHK-TT1A by using overlap PCR method and transformed into HMS174 cells. An aliquot mid-log phase cultures of the transformants were shocked at 48 °C and plated on LB plate (containing chloramphenicol). Afterwards, gene mutants were screened by using colony PCR and DNA sequencing. After the mutants were obtained, the phenotypes of ΔfliC and ΔdctA gene mutants were characterized by using agar puncture and carbon metabolism experiments. Colony PCR and sequencing results show that TeI3c/4c intron was inserted in the designed sites of fliC and dctA genes. The gene-targeting efficiency of Thermotargetron system was 100%. Phenotype verification experiments of the mutants demonstrated that the cell motility of all ΔfliC mutants was damaged and the malate assimilation ability of ΔdctA mutant was deprived comparing to wild-type HMS174 strain. In our study, a temperature-inducible and high-efficiency gene inactivation system was established for mesophilic bacteria. This system could achieve high efficiency and precise gene inactivation by modulation of the incubation duration of the transformants at 48 °C.