[Drug resistance and genomic characteristics of Salmonella enterica serovar London from clinical and food sources in Hangzhou City from 2017 to 2021].

Objective: To analyze the drug resistance and genomic characteristics of Salmonella enterica serovar London isolated from clinical and food sources in Hangzhou City from 2017 to 2021. Methods: A total of 91 Salmonella enterica serovar London strains isolated from Hangzhou City from 2017 to 2021 were analyzed for drug susceptibility, pulsed field gel electrophoresis (PFGE) typing and whole genome sequencing. Multilocus sequence typing (MLST), core genome multilocus sequence typing (cgMLST) and detection of drug resistance genes were performed by using the sequencing data. Phylogenetic analysis was conducted to compare the 91 genomes from Hangzhou City with 347 genomes from public databases. Results: No significant difference in the drug resistance rate was observed between clinical strains and food strains to 18 drugs in Hangzhou City(all P>0.05), and the multidrug resistance (MDR) rate was 75.8% (69/91). Most strains were resistant to 7 drug classes simultaneously. One strain was resistant to Polymyxin E as well as positive for mcr-1.1, and 50.5% (46/91) of the strains were resistant to Azithromycin and were positive for mph(A). All 91 Salmonella enterica serovar London strains were ST155, which were subdivided into 44 molecular types by PFGE and 82 types by cgMLST. Phylogenetic analysis showed that most strains from Hangzhou City (83/91) were clustered together, and a small number of human isolates from Europe, North America and pork isolates from Hubei and Shenzhen were mixed in the cluster. Other strains from Hangzhou City (8/91) were closely related to strains from Europe, America and Southeast Asia. Strains isolated from pork were the most closely related to clinical strains. Conclusion: The epidemic of Salmonella enterica serovar London in Hangzhou City is mainly caused by the spread of ST155 strains, which is mainly transmitted locally. At the same time, cross-region transmission to Europe, North America, Southeast Asia, and other provinces and cities in China may also occur. There is no significant difference in the drug resistance rate between clinical strains and food strains, and a high level of MDR is found in the strains. Clinical infection of Salmonella enterica serovar London may be closely related to pork consumption in Hangzhou City.

Elucidation of multiple alkane hydroxylase systems in biodegradation of crude oil n-alkane pollution by Pseudomonas aeruginosa DN1.

AIMS: The purpose of this study was to elucidate the characteristics of multiple alkane hydroxylase systems in Pseudomonas aeruginosa DN1, including two homologues of AlkB (AlkB1 and AlkB2 ), a CYP153 homologue (P450), and two homologues of Alm-like (AlmA1 and AlmA2 ). METHODS AND RESULTS: DN1 was capable of utilizing diverse n-alkanes with chain lengths from 8 to 40 C atoms as the sole carbon source, and displayed high degradation efficiency (＞85%) of crude oil and a majority of n-alkanes using gas chromatography method. RT-qPCR analysis showed that the five enzyme genes could be induced by n-alkanes ranging from medium-chain length to long-chain length which indicated the dissimilarity of expression between those genes when grown on different n-alkanes. Notably, the expression of alkB2 gene was upregulated in the presence of all of the tested n-alkanes, particularly responded to long-chain n-alkanes like C20 and C32 . Meanwhile, long-chain n-alkanes (C20 -C36 ) significantly elevated cyp153 expression level, and the expression of two almA genes was only upregulated in the presence of n-alkanes with chain lengths of 20C's and longer. Furthermore, the disruption of those genes demonstrated that AlkB2 appeared to play a key role in the biodegradation of substrates of a broad-chain length ranges, besides other alkane hydroxylase systems ensured the utilization of n-alkanes with chain lengths of from 20 to 40 C atoms. CONCLUSION: The five functional alkane hydroxylase genes make DN1 an attractive option for its versatile alkane degradation, which is primarily dependent on the expression of alkB2 . SIGNIFICANCE AND IMPACT OF THE STUDY: Our findings suggest that P. aeruginosa DN1 is a predominately potential long-chain n-alkane-degrading bacterium with multiple alkane hydroxylase systems in crude oil-contaminated environment.

Regioisomeric and enantiomeric analysis of primary triglycerides in human milk by silver ion and chiral HPLC atmospheric pressure chemical ionization-MS.

Triglycerides (TG) not only provide energy for infants but have important physiological functions. Understanding the composition and structure of TG in human milk is conducive to the development of infant formulas. In this study, TG species in human milk from 3 provincial capitals (Zhengzhou, Wuhan, and Harbin) in different regions of China were determined through C18 HPLC electrospray ionization tandem mass spectrometry (MS). The results showed that in human milk from these 3 regions, oleoyl-palmitoyl-linoleoylglycerol (OPL; 16.55, 19.20, and 18.67%, respectively) was more abundant than oleoyl-palmitoyl-oleoylglycerol (OPO; 10.08, 10.22, and 12.03%, respectively). Subsequently, regioisomeric and enantiomeric analysis of main TG in the human milk were performed on silver ion and chiral HPLC atmospheric pressure chemical ionization mass spectrometry (APCI)-MS, respectively. The results showed that rac-OPL (above 85%), rac-OPO (above 85%), rac-palmitoyl-oleoyl-oleoylglycerol (PPO; above 90%), and rac-OLaO (above 70%) were the main regioisomers of OPL, OPO, PPO, and lauroyl-oleoyl-oleoylglycerol (LaOO), respectively. The relative ratios of enantiomer pairs of rac-OPL (rac-OPL1 and rac-OPL2) were about 37 and 63%, respectively.

[Genomic analysis of a 2019-novel coronavirus (2019-nCoV) strain in the first COVID-19 patient found in Hangzhou].

Objective: To understand the viral genomic characteristics of a 2019-novel coronavirus (2019-nCoV) strain in the first COVID-19 patient found in Hangzhou, China. Methods: Viral RNA was extracted in throat swab and sputum sample of the patient and was performed real-time reverse transcription PCR detection and obtained viral genome by high-throughput sequencing method. Phylogenetic analysis was conducted using 29 2019-nCoV genomes and 30 ß-coronavirus genomes deposited in NCBI GenBank. Fifteen genomes from Wuhan were grouped by mutation sites and others were identified by Wuhan's or specific mutation sites. Results: A 29 833 bp length genome of the first 2019-nCoV strain in Hangzhou was obtained, covering full length of the coding regions of coronavirus. Phylogenetic analysis showed that the genome was closest to the genome of a bat SARS-like coronavirus strain RaTG13 with an identity of 96.11% (28 666/29 826). Among the genes between two genomes, E genes were highly conserved (99.56%), while S genes had lowest identity (92.87%). The genome sequence similarities among 29 strains from China (Hangzhou, Wuhan, and Shenzhen), Japan, USA, and Finland, were all more than 99.9%; however, some single nucleotide polymorphisms were identified in some strains. Conclusion: The genome of Hangzhou 2019-nCoV strain was very close to the genomes of strains from other cities in China and overseas collected at early epidemic phase. The 2019-nCoV genome sequencing method used in this paper provides an useful tool for monitoring variation of viral genes.

[Preliminary application of next generation sequencing technique in pathogen identification of foodborne disease].

Objective: To analyze genomic features of pathogens based on next generation sequencing technique in a food-borne disease event. Methods: A total of 11 blood samples, stomach contents before gastric lavage from the death and patients' foods were collected. S. aureus, B. cereus and toxic substances were detected. B. cereus detected in foods were counted. The conserved region of 16 S rDNA gene and ces gene(cereulide) of B. cereus isolates were detected by real-time PCR. Next Generation Sequencing (NGS) technology was applied to acquire genome sequences of isolates. Different plasmids distribution and comparative genomics analysis with reference sequences in public databases were analyzed. Results: Only B. cereus tested positive in all samples. The counts of B. cereus in Egg fried rice, one food samples, were 1.9×10(7) CFU/g, and the counts of B. cereus in dried and fried fish and brine pork head meat samples were 3.0×10(3) CFU/g both. Ten isolates were carrying hlyⅢ, nheA, nheB, inlA and inhA genes, and nine isolates carried the plcR gene and nine isolates carried the nheC gene. The PCR result of 16 S rDNA gene and ces gene of all isolates were positive. All carried the complete ces genes cluster sequence which were identical to the sequence of plasmid pCER270 (NC_01 0924.1) from strain AH187 in United Kingdom and pNCcld (NC_016792.1) from NC7401 in Japan. The alignment of plasmids turned out the sequence of the isolate differed from the pXO1 and pXO2 plasmids of B. anthracis, but carried the pNCcld plasmid containing the ces genes cluster. The phylogenetic tree based on genomic sequences of ten isolates showed high similarity (distances in phylogenetic tree from 2.0×10(-6)-9.0×10(-6)) to each other and to the B. cereus strains AH187 and NC7401 (MLST ST26 type, distances in phylogenetic tree from 3.8×10(-5)-4.5×10(-5)). Conclusion: The foodborne disease event was caused by vomiting type Bacillus cereus without plasmid pXO1 and pXO2 contaminated egg fried rice. The vomiting-type food poisoning caused by B. Cereus globally is probably associated with ST26, ST164 and other strains harboring ces gene.

Clinical and epidemiological survey and analysis of the first case of human infection with avian influenza A(H7N9) virus in Hangzhou, China.

To investigate and report on the clinical and epidemiological characteristics of the first case of human infection with avian influenza A(H7N9) virus in Hangzhou, China. A field epidemiological survey was used to study the first case in Hangzhou. The patient was a 39-year-old male chef with a history of exposure to a farm product market and to poultry prior to the onset of disease on 15 March 2013. He had diarrhea, chills, pyrexia, and intermittent cough with freshly red foamy bloody sputum early in his disease. His fever > 39 °C continued for a week with rapid progression. Computed tomography findings showed extensive bilateral consolidation, followed by multiorgan failure. The patient died on the morning of 27 March. His infection was eventually confirmed 1 week later on 3 April. Flu-like symptoms including fever and cough were found in 46 of his 138 close contacts. This was the first case of human infection with avian influenza A(H7N9) virus in Hangzhou. None of the close contacts had onset of the disease. The case patient's condition progressed rapidly. The source of infection might be his exposure to the farm product market, but the mode of exposure remains unclear.

Guiding outbreak management by the use of influenza A(H7Nx) virus sequence analysis.

The recently identified human infections with avian influenza A(H7N9) viruses in China raise important questions regarding possible source and risk to humans. Sequence comparison with an influenza A(H7N7) outbreak in the Netherlands in 2003 and an A(H7N1) epidemic in Italy in 1999­2000 suggests that widespread circulation of A(H7N9) viruses must have occurred in China. The emergence of human adaptation marker PB2 E627K in human A(H7N9) cases parallels that of the fatal A(H7N7) human case in the Netherlands.

Risk of multi-drug-resistant organism acquisition from prior bed occupants in the intensive care unit: a meta-analysis.

Multi-drug-resistant organisms (MDROs) have become a global threat to human health. Prior bed occupancy with MDRO infection/colonization is an exposure factor that is closely associated with the MDRO acquisition rates in subsequent bed patients in intensive care units (ICUs). A meta-analysis was conducted to investigate the risk of MDRO acquisition from prior bed occupants in the ICU. PubMed, Cochrane Library, Web of Science, and Embase databases and reference lists were searched for articles published up to December 2021. The Newcastle-Ottawa scale was used for quality assessment. The risk measure was calculated as the odds ratio (OR) and corresponding 95% confidence interval (CI), and the heterogeneity was tested using I2 method and Q test. Eight articles were analysed using a random-effects model. Of the 8147 patients exposed to prior bed occupants infected or colonized with MDROs, 421 had acquired MDROs. The control group consisted of 55,933 patients without exposure factors, of which 1768 had been infected/colonized with MDROs. The pooled acquisition OR for MDROs was 1.80 (95% CI: 1.42, 2.29), P<0.00001. Subgroup analysis based on multi-drug-resistant Gram-positive and Gram-negative organisms was conducted using a fixed-effects model. The results significantly varied between the groups. Heterogeneity was partially explained by the MDRO type. In conclusion, exposure of bed occupants to infected/colonized MDROs significantly increased the risk of MDRO acquisition in subsequent bed occupants.

Composition analysis of fatty acids and stereo-distribution of triglycerides in human milk from three regions of China.

Understanding the components composition characteristics of human milk is conductive for the development of infant formulas. The total fatty acids composition and the stereo-distribution of fatty acids in human milk triglycerides (TGs) from three regions (Zhengzhou, Wuhan and Harbin) of China were analyzed. The total and intrapositional fatty acids composition of human milk TGs showed significant differences among three regions. Zhengzhou, Harbin and Wuhan human milk possessed highest levels of medium-chain fatty acids (MCFA, 6.36 ±â€¯1.46%), short-chain fatty acids (SCFA, 0.10 ±â€¯0.03%) and monounsaturated fatty acids (MUFA, 34.61 ±â€¯0.45%), and polyunsaturated fatty acids (PUFA, 30.34 ±â€¯0.33%), respectively. The preference distribution of fatty acids in human milk TGs was hardly affected by regions, for the relative conservative interpositional levels of each fatty acids in three regions. Not only the specific distribution of sn-2 position, but the esterification of fatty acids in sn-1 and sn-3 positions also had preference. SCFA and MCFA were mainly esterified at sn-3 position, but LCSFA most unlikely distributed at the sn-3 position. The preference esterification of MUFA were sn-1, sn-3 > sn-2, and PUFA were sn-3 > sn-1 > sn-2. Therefore, the optimization of infant formulas not only needs considering total fatty acid composition of TGs but requires thinking over the stereo-distribution of fatty acids.

Knowledge and beliefs on corneal donation in Singapore adults.

AIM: To assess the knowledge and willingness of Singapore adults towards corneal donation. METHODS: The study population consists of a cluster random sample of the population living in Bedok North (an area in the eastern part of Singapore). The study population comprised residents aged 21-65 years living in 675 randomly sampled housing units. The participation rate was 65.9% (544/825). All participants were interviewed face to face with a questionnaire formulated according to the modified Horton and Horton model. Knowledge, values, attitudes, and spiritual beliefs of participants were assessed to evaluate their willingness to donate their corneas. RESULTS: 67.0% of participants were willing to donate their corneas. Ethnicity (Chinese) and religion (Christians, Hindus, or those with no religion) were associated with increased willingness to donate corneas. Greater knowledge and increased altruistic values were also associated with increased willingness to donate corneas. CONCLUSION: A proportion of participants were willing to donate their corneas. Awareness of corneal donation is high but specific knowledge should be further increased among adults.

Sorafenib combined with percutaneous radiofrequency ablation for the treatment of medium-sized hepatocellular carcinoma.

OBJECTIVE: Sorafenib, an oral multikinase inhibitor, is the proved therapy method for patients with advanced hepatocellular carcinoma (HCC). Based on heat delivery, Radiofrequency ablation (RFA) has been found to achieve complete neoplasm necrosis. It is the most widely performed percutaneous therapy for HCC. However, Study associated combined Sorafenib with RFA therapy for patients with advanced HCC has never been reported. The aim of present study is to explore the efficacy and safety of sorafenib combined with RFA therapy for the patients with medium-sized HCC. PATIENTS AND METHODS: A total of 62 patients diagnosed as HCC were involved in this study. All patients were randomly assigned to sorafenib and RFA (n=30) or RFA-alone (n=32) treatment groups. Treatment outcomes, including recurrence rates, time to progression (TTP) and adverse reactions induced by sorafenib were observed and recorded to assess the efficacy and safety of the combination method. RESULTS: During the overall follow-up period, the recurrence rate of the combination subgroup was 56.7% (17/30), and that of the RFA-alone subgroup was 87.5% (28/32) (p < 0.01). The median TTP was 17.0 months in the combination therapy vs. 6.1 months in the RFA-alone (p < 0.05). Hand-foot skin reactions were reported by 83.3% (25/30) of patients and 46.7% (14/30) reported diarrhea while the most adverse events (AEs) were mild to moderate in the combination subgroup. CONCLUSIONS: Sorafenib combined with RFA significantly decreased recurrence rates and prolonged the survival time of medium-sized HCC patients. The combination therapy is safer and more effective than the control without unexpected side effects. Furthermore, the earlier application, the better results were.

Epileptiform activity and hippocampal damage produced by intrahippocampal injection of guanidinosuccinic acid in rat.

Guanidinosuccinic acid (GSA) is a guanidino compound found in mammalian central nervous system and physiological fluids. Its level has been found to be greatly increased in serum and cerebrospinal fluid of patients with renal failure, and the compound is suggested to play a role in uremic encephalopathy. In this report we examined the behavioral, electrographic and morphological effects of intrahippocampal GSA injection in unanesthetized rats. Intrahippocampal administration of 2 microliters GSA solution (3.5 nM) was followed by behavior observation, and electrohippocampographic and electrocorticographic recording. GSA-injected animals showed partial clonic seizures leading to generalized clonic seizures, and eventually status epilepticus. These were accompanied by epileptiform electrographic discharges. During generalized clonic seizures, the electrohippocampogram showed arythmic bursting spikes. Epileptiform electric activity persisted even after the generalized clonic convulsions had stopped, and lasted until the animals were killed, 5 days following injection. Microscopic examination of brain slices of these rats revealed severe neural damage in CA1 area of hippocampus. Treatment of rats with the non-competitive NMDA receptor antagonist ketamine prevented both partial and generalized clonic seizures, epileptiform electrographic discharges, and GSA-induced hippocampal damage.

Traumatic eye injuries due to large unusual foreign bodies: a Singapore case series.

PURPOSE: Traumatic eye injuries due to large foreign bodies (FB) are rare. The visual prognosis is often poor in these cases because of severe ocular damage. Staged surgical procedures with eventual enucleation or evisceration are often indicated. METHODS: Case series. RESULTS: The authors describe two patients with eye injury due to large FB with visual acuity of no light perception at presentation. Both had initial repair of the ocular injuries and removal of the FB. One patient with an intraocular FB eventually underwent enucleation; the other, with intraorbital FB, had evisceration as a secondary procedure. Orbital implantations were done in both. Neither of the patients had developed sympathetic ophthalmia at the last review. CONCLUSIONS: The visual outcome of eye injuries due to large FB is poor. Both enucleation and evisceration can be performed with low risk of sympathetic ophthalmia. Prevention remains the best approach to such devastating injuries.

[Antagonism of piracetam on the amnestic effect of diazepam in mice].

In step-down test, diazepam (1 mg.kg-1 po, 1 h before training) was shown to significantly impair memory acquisition in mice. But piracetam (200 mg.kg-1 ip, 1 h before training) was found to improve the diazepam-induced impairments of learning. By photocell cage method, piracetam showed no significant inhibitory effect on the diazepam-induced spontaneous motor activity in mice. In Y-maze test, Glutamic acid (0.1 microgram, icv, 3 min before training) significantly improved learning in normal mice and the amnesic effect of GABA and diazepam were completely antagonized by Glutamic acid and piracetam (200 mg.kg-1 ip, 1 h before training). These results suggest that increasing GABA-ergic neuronal transmission is unfavorable to learning and memory, but increasing Glu-ergic transmission is contrary to the former. It seemed that the presence of Glu/GABA system in the brain could regulate learning and memory.

[Seizure activity and lesions of neuronal cells by intrahippocampal injection of guanidinosuccinic acid in rats].

Intrahippocampal injection(ihci) of guanidinosuccinic acid (GSA) to rats, induced typical generarized clonic seizures and epileptiform discharges in electrohippocampogram (EHG) and electrocorticogram (ECoG), degenerative changes of neuronal cells in the injected side hippocampus. The pyramidal cells in CA1 area were found to be more vulnerable to GSA than the granular cells. Phenobarbital and phenytoin are typical antiepiletics, but in no case did they successfully protect against GSA induced convulsions, epileptiform discharges in the EHG and ECoG and neurolysis. Ketamine, a selective noncompetitive NMDA receptor antagonist, was shown to protect against not only seizures, but also neuronal cell damage induced by GSA. All these results indicate that GSA very like the endogenous excitatory amino acid, glutamic acid, it also has such effects mentioned above. Therefore, the NMDA receptor may mediate both effects of GSA.

A new sesquiterpene lactone glucoside with inhibitory effect on K562 cells from Ixeris sonchifolia (Bge) Hance.

A new minor sesquiterpene lactone glucoside, ixerin ZA (1), together with 16 known compounds, were isolated from the whole plants of Ixeris sonchifolia (Bge) Hance. The structure of 1 was elucidated as 1(10),3,11(13)-guaiatriene-12,6-olide-2-one-3-O-[6'-(p-metheoxyphenylacetyl)]-beta-glucopyranoside on the basis of spectroscopic and chemical evidence. Compound 1 exhibited an inhibitory effect on K562 cells.

Hypoglycemia leads to age-related loss of vision.

The retina is among the most metabolically active tissues in the body, requiring a constant supply of blood glucose to sustain function. We assessed the impact of low blood glucose on the vision of C57BL/6J mice rendered hypoglycemic by a null mutation of the glucagon receptor gene, Gcgr. Metabolic stress from moderate hypoglycemia led to late-onset loss of retinal function in Gcgr(-/-) mice, loss of visual acuity, and eventual death of retinal cells. Retinal function measured by the electroretinogram b-wave threshold declined >100-fold from age 9 to 13 months, whereas decreases in photoreceptor function measured by the ERG a-wave were delayed by 3 months. At 10 months of age Gcgr(-/-) mice began to lose visual acuity and exhibit changes in retinal anatomy, including an increase in cell death that was initially more pronounced in the inner retina. Decreases in retinal function and visual acuity correlated directly with the degree of hypoglycemia. This work demonstrates a metabolic-stress-induced loss of vision in mammals, which has not been described previously. Linkage between low blood glucose and loss of vision in mice may highlight the importance for glycemic control in diabetics and retinal diseases related to metabolic stress as macular degeneration.

Epoxidation of the lindane metabolite, beta-PCCH, by human- and rat-liver microsomes.

Human- and rat-liver microsomes convert the lindane metabolite, beta-PCCH (beta-1,3,4,5,6-pentachlorocyclohex-1-ene (3,4,6/5-PCCH] to the metabolites: 1,2,4-TCB (1,2,4-trichlorobenzene), 1,2,3,4-TTCB (1,2,3,4-tetrachlorobenzene), 2,4,5-TCP (2,4,5-trichlorophenol), 3,4,5/6-PCCOL (1,2,4,5,6-pentachlorocyclohex-1-en-3-ol) and beta-PCCH oxide (1,2,3,4,5-pentachloro-7-oxabicyclo[4.1.0]heptane) or (3,4,6/5-PCCH oxide). The identity of the beta-PCCH oxide is confirmed by column chromatography and g.l.c.-mass spectrometry, in comparison to characterized synthetic material. The stability of the beta-PCCH oxide is indicated by its resistance to hydrolysis by microsomal epoxide hydrolase (EC. 3.3.2.3), or various aqueous acid conditions. It shows no mutagenicity using S. typhimurium strain TM677. However, in levels above 0.05 mg/ml it was lethal to the test cells. It is not a substrate for and is only a weak inhibitor of epoxide hydrolase. A stable halogenated hydrocarbon epoxide metabolite is described. Its toxicological role, if any, remains unaccounted for.

[Antagonism of Zn2+ on nootropic action of piracetam in mice].

In mouse step-down test, the memory impairments of acquisition, consolidation and recognition were induced by anisodine, chloramphenical and ethanol, respectively. Piracetam 100 mg/(kg.d) ip for 5 d improved the anisodine-induced impairment of learning. ZnSO4 5 mg/(kg.d) po for 5 d did not improve the 3 impairments. Memory impairments were enhanced by a combined administration of ZnSO4 and piracetam in these 3 models. These results were confirmed by Y-maze method in normal mice.