Molecular characterization of antimicrobial multi-drug resistance in non-typhoidal Salmonellae from chicken and clam in Mangalore, India

Salmonella enterica has been documented as one of the leading causes of salmonellosis throughout the world and is most commonly associated with the consumption of contaminated food products. Thus, this research was aimed at studying the antimicrobial susceptibility pattern and detection of quinolone resistance in Salmonella spp isolated from food of animal origin. Thirty-six Salmonella isolates comprising 8 from poultry and 28 from seafood（clams） were identified, serotyped and characterized for their antimicrobial susceptibility against 10 different antibiotics. Plasmid DNA was isolated from all the isolates by alkaline lysis, quinolone resistant non-typhoidal S. Weltevreden were examined for mutation in the DNA gyrase coding gene. Among the 36 Salmonella isolates, 20 were S. weltevreden（8 from poultry and 12 from seafood） and 16 were S. Typhimurium（from seafood）. All the isolates showed multiple resistance to nalidixic acid, tetracycline, co-trimoxazole and nitrofurantoin, but, interestingly, the isolates were 100% susceptible to ampicillin, chloramphenicol and gentamicin. Resistant isolates from the study carried the genes responsible for resistance to respective antibiotics. The strain S130 isolated in the study showed single point mutation,Asp87Gly, at position 87 in quinolone resistance determining region. It revealed mutation in quinolone resistance determining region as a cause for quinolone resistance in non-typhoidal Salmonellae. The occurrence of genes accountable for plasmid mediated resistance to quinolones（viz., qnrA, qnrB and qnrS） in plasmid of non-typhoidal Salmonellae isolates provides evidence for plasmid mediated quinolone resistance.

Association of Phenotypic and Genotypic Fluoroquinolone Susceptibility among Non-Typhoidal Salmonella Isolates from Jeddah, KSA

Non-typhoid Salmonella (NTS) infects 250 to 3200 per 100,000 individuals from all over the world. NTS infection is relatively high in Jeddah (ranges between 44-132/100,000 population) as compared to other cities of Saudi Arabia. NTS isolates have also shown increasing resistance to conventional antibiotics. Therefore, fluoroquinolone (FQ) is considered drug of choice for the treatment of invasive NTS infections. A rapid detection of FQ resistance may greatly assist in appropriate therapy and containment of resistant NTS strains. Thus, molecular detection of mutations in FQ resistance genes (gyrA and parC) may play a promising role. Since limited data were available about FQ resistance among NTS isolates, therefore, this study primarily explored the occurrence of phenotypic and genotypic FQ resistance among NTS isolates from Jeddah, Saudi Arabia. Study also explored any correlation between phenotypic and genotypic FQ resistance. Fifty NTS isolates were collected from a public sector hospital of Jeddah from January to December, 2014. FQ susceptibility was determined for 48 NTS isolates using Kirby-bauer disk diffusion method and results were interpreted according to Clinical and Laboratory Standards Institute (CLSI) methodology. Genotypic resistance to FQ was determined by exploring mutations in gyrA and parC genes using PCR- based gene-sequencing method. Results were statistically analyzed using Social Package of Statistical Science (SPSS) version 22. Phenotypic antibiogram revealed that 38% (18/48) NTS isolates were FQ resistant, that 23% (11/48) were intermediately susceptible and that 39% (19/48) were susceptible. Genotypic resistance revealed mutations in only four codons of gyrA and parC genes among 39% (7/18) of FQ resistant isolates. 43% (3/7) of FQ resistant isolates showed mutations at two codons 83 (S83F, S83Y) and 87, (D87G, D87Y, D87W) of gyrA gene. Two resistant isolates showed triple mutations i.e. at codons 83 and 87 of gyrA and codon 80 (S80I and S80W) of parC gene, while one resistant isolate revealed mutation at codon 87 of gyrA and 57 (S57T) of parC gene. Moreover, 55% (6/11) intermediately susceptible isolates for FQ also revealed mutation at codon 83 of gyrA gene whereas;one intermediately susceptible isolate (1/6) also revealed additional mutation at codon 57 of parC gene. None of the FQ susceptible NTS isolates showed any mutations in gyrA or parC genes. Occurrence of mutations at only four codons in gyrA and parC genes among FQ resistant isolates may assist in development of rapid molecular method for FQ resistance detection. Presence of mutations among more than fifty percent of intermediately susceptible FQ isolates is alarming and may serve as a predictor for pre-resistant isolates for FQ. Moreover, absence of mutation in about sixty percent of phenotypically FQ resistant NTS isolates shows existence of an alternate resistance mechanism requiring further investigations.

Detection of Non-Typhoidal Salmonella Using a Mechanism for Controlling Hydrogen Sulfide Production

To know the relation between NaCl concentration and hydrogen sulfide (H2S) production by MY Phenomenon of Salmonella, we developed a method to control H2S production by Salmonella in this study. Desoxycholate-hydrogen sulfide-lactose (DHL) agar was used as the selective medium for Salmonella. Triple sugar iron (TSI) agar was used as the screening medium. Citric acid disks were placed on DHL agar. NaCl was added to both media. After 24 hours incubation, H2S production on DHL agar was stimulated by citric acid, whereas production was suppressed by adding NaCl. The color change in the bottom of the TSI medium was due to the low production of black FeS. The production of FeS was reduced by lower H2S production by Salmonella with an increasing concentration of NaCl from 0.5% to 3%. The inhibition of the black color meant that the color change due to glucose fermentation could be seen clearly in the bottom of the agar. The current method cannot detect glucose fermentation but the addition of more NaCl to the TSI medium allowed the visualization of glucose fermentation by Salmonella. Although H2S production of salmonella was promoted by citrate etc., being controlled by sodium chloride was proved in this study. Thus, we had developed a possibility of novel technique for the detection of Salmonella etc.

Occurrence of Typhoidal and Non-Typhoidal Salmonellae among Poultry Workers in the Southern, Nigeria

Typhoid fever and non-typhoidal salmonellosis remain endemic in most developing countries with large scale transmission through contaminated food and drinking water. Since the early 2000s, poultry has also been found to be a common food source for Salmonella enteritidis infections. A total of 500 blood, stool, cloaca swab and egg shell swab specimens were collected respectively from poultry, non-poultry workers and birds in Akwa Ibom State and screened for Salmonella species using standard cultural and serological techniques. The overall prevalence rate was 117 (23.4%). Salmonella species were distributed in all the three senatorial districts of the State, percentage distribution of Salmonella isolates was 42 (25%) for Uyo, 35 (20.8%) for Eket and 40 (23.8%) were isolated from Ikot Ekpene senatorial districts. Out of 372 human subjects screened 77 (20.7%) were positive and 38 (20.4%) were isolated from non-poultry workers while 39 (21.0%) were isolated from poultry Staff in the three senatorial districts. Out of 128 samples of poultry products analysed 40 (31.3%) were isolated. 23 (18%) were isolated from cloaca swabs while 17 (13.3%) were isolated from egg shell swabs. In this study, all the serological significant Typhoid fever cases were confirmed by blood culture. According to sero-grouping and source of sample collection 23.9% S. typhi was isolated from human followed by S. paratyphi A (20.5%) while S. enteritidis and S. gallinarum (19.7%). Among poultry products S. gallinarum, S. enteritidis, S, pullorum, S. paratyphi A, and S. typhimurium were isolated from bird Cloaca swab and Egg shell swab. Salmonella pullorum and S. typhi were not isolated from human and poultry respectively. High prevalence of Salmonella serovars such as S. gallinarium, S. typhi, S. Typhimurium and S. enteritidis with regular consumption of poultry and eggs without proper disinfection and appropriate boiling represent a serious public health risk in Akwa Ibom State. Demographic data obtained in this study showed that majority of the poultry workers across the three senatorial districts were within the ages of 21 to 30 (34%), 39% were none graduate while 30.4% were secondary school leavers. Fever was recorded as the highest clinical signs and symptoms followed by headache, abdominal cramps, diarrhoea and vomiting. Generally, all the isolates identified as Salmonella were tested for their susceptibility to antimicrobial agents. The results showed that Amoxacillin-Clavulanic acid was 100% susceptible to S. gallinarum, S. paratyphi A, 93% susceptible to S. typhi and 80% to S. typhimurium, S. enteritidis and S pullorum. Salmonella gallinarum was 100% sensitive to Ciprofloxacin and S. pullorum, whereas all isolates were 100% resistant to Oxacillin and Tylosin antibacterial agents used. The emergence of multiple drugs resistant Salmonella from human and poultry shows that the continuous use of drugs in poultry as growth promoters should be re-examined. Other factors as sources of Salmonella contamination in farms can be minimized by good hygienic practices and biosecurity measures.

Non-typhoidal salmonella:an unusual cause of spontaneous bacterial peritonitis in decompensated cirrhosis

Salmonella typhimurium, a non-typhoidal salmonella, is an unusual cause of spontaneous bacterial peritonitis (SBP). It isusually reported in asymptomatic patients with normal or high ascitic fluid protein levels with underlying immunosuppression,as high opsonic activity in the ascitic fluid of these patients protects them from the usual organisms causingspontaneous bacterial peritonitis, unless they are exposed to a particularly virulent organism like salmonella. We report acase of culture-proven non-typhoidal salmonella in a patient with decompensated cirrhosis, with low protein and withoutany underlying immunosuppression, and no other source to explain its origin.

Salmonella Berta myocarditis:Case report and systematic review of non-typhoid Salmonella myocarditis

AIM: To study trends in the epidemiology,clinical presentation,microbiology and prognosis of nontyphoid Salmonella(NTS) myocarditis.METHODS: We performed a systematic literature search for all reported NTS cases. The search yielded 838 publications. A total of 21 papers were deemed eligible. No language restrictions were enforced. Articles that were not written in English were translated. Pre-specified data such as clinical presentation,electrocardiogram(ECG) changes,transthoracic echocardiographic findings,cardiac magnetic resonance findings,microbiology cultures,Salmonella species,inflammatory markers(erythrocyte sedimentation rate and C-reactive protein),cardiac biomarkers and severity of illness were collected using data extraction sheets. Cases were classified by age into 2 groups; pediatric cases(defined as < 18 years old) and adult cases(defined ≥ 18 years old). The mean age of patients and standard deviations were calculated. The data was analyzed with IBM SPSS Statistics(Windows,Version 20.0. Armonk,NY: IBM Corp.) for demographic characteristics,presenting symptoms,microbiology,diagnostic methods,treatment modalities and outcome.RESULTS: From the selected articles,we identified a total of 24 individual cases with verifiable data. There were 20 males with a male to female ratio of 5:1. The mean age at presentation was 30.8 years(range 1 mo-67 years),16% of cases were children aged < 18 years. Most patients presented with chest pain,fever,and abdominal pain. The most common ECG finding was ST elevation. Cardiac biomarkers were elevated in around 70% of cases. Salmonella Enteritidis was the most common NTS isolated. Definitive diagnosis was established by blood and stool cultures in most of the cases. The pediatric and adults cases had similar incidence of bacteremia(40% vs 36.8%) while the pediatric group had more stool cultures positive compared to the adult group(100% vs 63.1%). Eightythree percent of patients received antibiotics and 58% were successfully treated through conservative management. The overall mortality was 24% and 42% of patients required intensive care.CONCLUSION: This systematic review of published cases shows that NTS myocarditis occurs predominantly in young adults and carries a poor prognosis.

Detection of non-typhoid Salmonella infection by citrus and citrus extracts in Lao PDR

Objective:To know the current state of non-typhoid Salmonella infection in Laos.To examine the usefulness of new screening methods for Salmonella using citrus.Methods:Non-typhoid Salmonella infection of person in Lao PDR was studied in this research(2004-2009).The site was Vientiane capital city in 2004.Research from rural villages locating suburb of Vientiane during 2005-2008 was carried out.Rural villages in Attapu province where ethnic minorities were living was searched for this study in 2009.During this research,to detect Salmonella strain, a new method using citrus and citrus extract named MY phenomenon that observing black ring (MIDO ring) on DHL agar was tried.The slice lemon and lime were used for this trial in 2004. After 2005,disk of ascorbic acid and citric acid were used for the device instead of citrus fruits itself.Results:During this research,65 of 272 human samples(23.9%) were infected with non- typhoid Salmonella.Conclusions:During this study,the method using citrus and citrus extracts was accepted for the detection of Salmonella.This study shows that with citrus and citrus extract, detection of Salmonella is possible using only DHL media.Results suggest that infectious rate of non-typhoid Salmonella was high.

Antibiotic Resistance Profile of Salmonella Strains Isolated at the National Clinical Biology and Public Health Laboratory in Bangui, Central African Republic

In Africa, each year, there are estimated to be more than 91 million cases of salmonellosis and 137,000 cases of death. The problem of antibiotic resistance in Salmonella strains is a threat to public health. The objective of this study is to evaluate the antibiotic resistance profile of Salmonella strains isolated in biological products analyzed at the National Laboratory of Clinical Biology and Public Health (NLCBPH) in Bangui. This is, therefore, a cross-sectional study with a descriptive aim, running from January to December 2022. It focused on the strains of Salmonella isolated and identified in stools, urines, and blood samples. For each strain of Salmonella isolated, an antibiogram was carried out following the recommendations of the French Society of Microbiology (CASFM, 2022). A total of 93 strains of Salmonella have been recorded. The age group 0 - 9 years was 29% and that of >50 years was 11%. The median age of patients was 30 years with a minimum of 1 and a maximum of 78 years. The female gender was more represented at 52.69% than the male gender at 47.31%, i.e. a sex ratio of 0.89 (M/F). Salmonella strains were much more isolated in stools at 62% followed by urines at 29% and blood at 6%. Salmonella arizonae strains were more represented with 52%. Salmonella strains have a resistance rate to Tetracycline of 62.37% followed by Penicillins of 50%. The rate of multi-antibiotic resistance of the Salmonella strains isolated represented 48.38%. Salmonella spp. strains were multi-resistant at 58.69% followed by Salmonella arizonae strains at 47.91%. There is a significant association between the different families of antibiotics and Salmonella strains (p < 0.05). According to the results obtained, Penicillins, Phenicoles, and Cyclins had a high rate of resistance on Salmonella strains. No strain-producing Broad Spectrum Beta-lactamase has been isolated. Salmonella strains represent a zoonotic health danger, constitute a public health problem and remain a current subject. This germ is resistant to the antibiotics used. It is, therefore, essential to emphasize monitoring the resistance of these germs in the Central African Republic (CAR) to improve the health of the population.

Case Report: Bilateral Intra-Parenchymal Hematomas Caused by Ventricular Flood Complicating Neonatal Salmonella typhi Meningitis

Salmonella meningitis is an uncommon condition in neonates, and when it does occur, it is often linked to serious complications, such as subdural collections and abscesses. We present a case involving a 23-day-old neonate diagnosed with Salmonella meningitis, who developed complications including bilateral intra-parenchymal hematomas with ventricular involvement. The infant showed significant improvement following an extended course of systemic antibiotics and supportive care.

Anti-biofilm and anti-virulence potential of cell free supernatant of Akkermansia muciniphila against Salmonella

Akkermansia muciniphila is one of the commensals residing within the mammalian gut and co-evolving with the host.Numerous studies have demonstrated the benefits of A.muciniphila in ameliorating metabolic disorders,while little is known about the antimicrobial potential of A.muciniphila against pathogens.Here,we examined the antimicrobial and anti-virulence properties of cell free supernatant(CFS)of A.muciniphila against Salmonella Typhimurium.CFS retarded bacterial growth and inhibited the motility of S.Typhimurium SL1344 and S.Typhimurium 14028.CFS dose-dependently reduced cell hydrophobicity and auto-aggregation of both strains.Also,CFS from A.muciniphila significantly attenuated biofilm formation.Compared with untreated bacteria,CFS-treated bacteria significantly decreased adhesion and invasion to Caco-2 cells,and reduced intracellular survival in macrophages.CFS maintained antimicrobial properties after treatment with high temperatures and various proteases,while it lost its antimicrobial activity after pH neutralization.Gas chromatography-mass spectrometry(GC-MS)confirmed that A.muciniphila produced a certain amount of acetate and propionate,and ultra-high-performance liquid chromatography-mass spectrometry(UHPLCMS)identified other organic acids and metabolites in CFS.In summary,CFS from A.muciniphila exhibited anti-biofilm and anti-virulence properties against Salmonella and could be potentially utilized in the food industry for controlling Salmonella contamination and reducing infection.

Low interleukin-10 level indicates a good prognosis in Salmonella enterica serovar typhimurium-induced pediatric hemophagocytic lymphohistiocytosis:A case report

BACKGROUND Secondary hemophagocytic lymphohistiocytosis(sHLH)triggered by Salmonella enterica serovar Typhimurium is rare in pediatric patients.There is no consensus on how to treat S.typhimurium-triggered sHLH.CASE SUMMARY A 9-year-old boy with intermittent fever for 3 d presented to our hospital with positive results for S.typhimurium,human rhinovirus,and Mycoplasma pneumoniae infections.At the time of admission to our institution,the patient’s T helper 1/T helper 2 cytokine levels were 326 pg/mL for interleukin 6(IL-6),9.1 pg/mL for IL-10,and 246.7 pg/mL for interferon-gamma(IFN-γ),for which the ratio of IL-10 to IFN-γwas 0.04.In this study,the patient received meropenem,linezolid,and cefoperazone/sulbactam in combination with high-dose methylprednisolone therapy(10 mg/kg/d for 3 d)and antishock supportive treatment twice.After careful evaluation,this patient did not receive HLH chemotherapy and recovered well.CONCLUSION S.Typhimurium infection-triggered sHLH patient had a ratio of IL-10 to IFN-γ≤1.33,an IL-10 concentration≤10.0 pg/mL,and/or an IFN-γconcentration≤225 pg/mL at admission.Early antimicrobial and supportive treatment was sufficient,and the HLH-94/2004 protocol was not necessary under these conditions.

Multidrug-Resistant of Escherichia coli and Salmonella spp. Strains in Chicken Feces Intended for Consumption in Open Spaces of Ouagadougou, Burkina Faso

Resistant bacteria can be transmitted to humans through feces or contaminated meat from local chickens. Bacterial strains were isolated from the intestinal contents of 400 local chicken samples from various sales sites. These strains were then characterized using bacteriological and biochemical methods to identify resistant strains. In a study conducted in Ouagadougou, we systematically collected chicken fecal samples from 20 locations across the city, followed by isolation and identification of Salmonella spp. using specific enrichment and culture methods, as well as Escherichia coli. Bacterial strains were characterized using antibiotic resistance profiles were determined through agar diffusion tests, revealing sensitivity or resistance to a range of antibiotics based on established scientific criteria. The results showed that out of the 400 samples collected, 81.25% and 63.5% were contaminated by Escherichia coli and Salmonella spp., respectively. Among these, 86.15% of identified Escherichia coli and 50.78% of Salmonella spp. displayed resistance to at least one tested antibiotic. Among 280 Escherichia coli isolates identified resistant to at least one antibiotic, 31.07% were resistant to cefotaxime (CTX), 20.35% to ceftazidime (CAZ), 21.07% to ceftriaxone (CTR), 75% to amoxicillin clavulanic acid (AMC), 23.57% aztreoname (ATM) and 27.14% were resistant to imipenem (IMP). In the case of the 129 Salmonella spp. isolates resistant to at least one tested antibiotic, 34.88% were resistant to CTX;41.08% to CAZ;35.65% to CTR, 92% to AMC, 39.53% to ATM and finally 47.28% were resistant to IMP. Our study revealed high prevalence of resistance in bacterial strains isolated from local chickens sold outdoors in Ouagadougou. These findings raise significant public health concerns, due to the possible transmission of these resistant strains to humans through the consumption of contaminated meat, thus complicating the treatment of bacterial infections.

Survey of Multidrug Resistance and Class I Integron Prevalence in Chicken-derived Salmonella

[Objective] This study aimed to investigate the multidrug resistance and prevalence of class I integrons in Salmonel a. [Method] Salmonel a strains were isolated from chicken farms in Shandong Province. Kauffmann-White classification method was employed to analyze the serotypes of Salmonel a strains. Minimum in-hibition concentration （MIC） of Salmonel a strains against 19 common antimicrobial drugs was analyzed determined with microdilution method. The class I integrons and carried drug resistance gene cassettes were detected by PCR. [Result] A total of 311 Salmonel a strains were isolated and classified into two serotypes, including 133 Salmonel a Indiana strains and 178 Salmonel a Enteritidis strains. Drug sensitivity test showed that the isolated Salmonel a strains were general y resistant to sulfadiazine, sulfamethoxazole, nalidixic acid, ampicil in, tetracycline, doxycycline and trimethoprim, with a multidrug resistance rate of 91.0% （283/311）; 99% strains were sensitive to amikacin and colistin. PCR assay indicated that the detection rate of class I integrons was 65.0% （202/311）; the positive rate of class I integrons in Salmonel a strains with multidrug resistance was 92.6%; among 202 positive strains, six strains carried gene cassette dfr17-aadA5. [Conclusion] According to the above results, class I integrons exist general y in Salmonel a and are closely associated with the multidrug resistance of Salmonel a strains.

Salmonella hadar对喹诺酮类药物耐药性及其耐药基因分析

目的:研究新疆乌鲁木齐市部分农贸市场内检出的21株Salmonella hadar对2种喹诺酮类抗生素的药敏性及相关耐药基因,更好地了解耐药性的产生和传播途径,确保食品安全。方法:用琼脂稀释法测定Salmonella hadar的药敏性,用聚合酶链式反应和测定基因序列的方法确定耐药沙门氏菌中与喹诺酮类抗生素耐药性相关的喹诺酮类抗性决定区突变基因以及质粒携带的耐药基因。结果:21株Salmonella hadar对萘啶酮酸的耐药率达100%,对环丙沙星表现为敏感;qnrB、qnrA、qnrS基因的检出率分别为52.30%、4.76%、4.76%;21株Salmonella hadar均为gyrA和parC基因同时突变,gyrA基因的突变类型是Ser83Phe,parC基因的突变类型是Thr57Ser。结论:新疆乌鲁木齐Salmonella hadar对喹诺酮类药物的耐药状况应当予以关注,其耐药决定区突变基因及质粒携带的耐药基因在一定程度上会影响Salmonella hadar的耐药机制。

抗Salmonella minnesota R_(595)菌脂多糖杂交瘤的建立及其抗体特性的初步鉴定

将煮沸致死的R595菌体免疫BALB/C小鼠,取其脾细胞在PEG介导下与SP2/0细胞融合,经筛选获得2个阳性孔2D6、3H4。将2D6、3H4阳性孔细胞克隆,传代最终获得8株能稳定分泌抗R595内毒素单抗的杂交瘤株。经鉴定,杂交瘤细胞染色体数90余条,抗体效价（EL1SA法）104～105,2D6B1,2D6E7单抗的Ig类型为IgG1,3H42F7、3H42H3单抗Ig类型为IgG2b,轻链均为K链。类脂A抑制试验显示,单抗识别的表位为类脂A或KDO,表明抗体识别内毒素保守区域。间接EL1SA试验表明,抗体能与多种GNB交叉反应,提示抗体具广谱交叉反应性。玻片凝集试验显示,抗体仅能凝集R595菌,不能凝集其它GNB菌。

Isolation and Drug Resistance Analysis of Swine Salmonella

In this study, 68 fresh pork samples were collected from several major wholesale markets in Dalian City of Liaoning Province to isolate Salmonella using SS agar medium as selective medium. Salmonella isolates were identified with colony morphology observation and PCR method. The resistance of Salmonella iso- lates to 15 antibiotics was analyzed by broth microdilution susceptibility test. Accord- ing to the result, 12 Salmonella strains were isolated from 68 fresh pork samples, indicating a detection rate of 17.64%; 83.33% of Salmonella strains isolated from fresh pork samples could at least resist one antibiotic; Salmonella strains exhibited the strongest resistance to florfenicol （75.0%）, sarafloxacin hydrochloride （66.7%）, neomycin sulfate （66.7%） and doxycycline hydrochloride （66.7%）, followed by oxyte- tracycline （58.3%）, gentamicin sulphate （58.3%） and mequindox （58.3%）; Salmonella strains exhibited relatively low resistance to ciprofloxacin lactate （50.0%）, en- rofloxacin （50.0%）, ciprofloxacin hydrochloride （50.0%）, amoxicillin （16.7%） and col- istin sulphate （16.7%）. Salmonella in fresh pork samples from wholesale markets in Dalian Economic ＆ Technological Development Zone exhibited a high detection rate, and the isolated Salmonella strains showed extremely high resistance to various an- tibiotics. The strong drug-resistance of Salmonella can also be transmitted through the food chain from the food to the people, which should attract sufficient attention.

生姜中Salmonella enterica的分离与宿主氧化应答

本研究对重庆荣昌采后发病姜块进行病原菌分离鉴定,分离到一株新的生姜致病菌。通过细菌形态、生理生化、16S r DNA遗传分析鉴定为沙门氏菌(Salmonella enterica)。将沙门氏菌回接姜苗、姜块,发现姜苗叶片失绿,褶皱;姜块表面水渍并有分泌物;动态污染研究表明:沙门氏菌能在姜块中迅速繁殖,显著提高姜块超氧化物歧化酶(superoxide dismutase,SOD)、过氧化物酶(peroxidase,POD)、过氧化氢酶(catalase,CAT)的活性。该研究表明,沙门氏菌能以生姜为寄主存活。

1990—2019年中国三种肠道传染病发病和死亡趋势分析及预测研究

背景肠道传染病是常见的传染性疾病之一,分析和预测其流行现状能够为肠道传染病的防治提供一定的参考。目的了解1990—2019年中国腹泻病、伤寒与副伤寒和侵袭性非伤寒沙门菌肠道感染3种肠道传染病的发病和死亡情况,并预测2020—2030年其发病率和死亡率,为肠道传染病的防控提供参考。方法基于2019全球疾病负担研究数据库(GBD),收集1990—2019年中国腹泻病、伤寒与副伤寒和侵袭性非伤寒沙门菌肠道感染3种肠道传染病的发病和死亡数据,根据变化率(%)和年估计百分比(EAPC)分析以上3种肠道感染疾病的变化趋势。利用自回归移动平均模型(ARIMA)预测2020—2030年中国以上3种肠道传染病的发病率和死亡率。结果1990—2019年腹泻病的发病率变化无统计学意义(EAPC=0.09,P>0.05),而伤寒与副伤寒和侵袭性非伤寒沙门菌肠道感染的发病率均呈下降趋势(EAPC分别为-4.0%、-0.64%,P<0.05)。1990—2019年腹泻病、伤寒与副伤寒和侵袭性非伤寒沙门菌肠道感染的死亡率均呈下降趋势(EAPC分别为-8.39%、-3.38%、-1.87%,P<0.05)。在各年龄组中,2019年≥70岁人群腹泻病的发病率在各年龄组中最高,且呈上升趋势(EAPC=0.27,P<0.05)。1990—2019年所有年龄组以上3种肠道传染病的死亡率均呈下降趋势(P<0.05)。ARIMA模型预测结果显示,2020—2030年我国腹泻病发病率呈上升趋势,伤寒与副伤寒和侵袭性非伤寒沙门菌的发病率呈下降趋势,预计以上3种疾病的发病率分别为58793.04/10万、5.26/10万、0.447/10万。此外,2020—2030年我国腹泻病、伤寒与副伤寒和侵袭性非伤寒沙门菌的死亡率均呈下降趋势,预计2030年以上3种疾病的死亡率分别为0.214/10万、0.039/10万、0.026/10万。结论2030年我国腹泻病、伤寒与副伤寒和侵袭性非伤寒沙门菌肠道感染的死亡率呈下降趋势;除腹泻病的发病率呈上升趋势外,其余两种疾病的发病率呈下降趋势,提示政府及相关卫生部门应当重视关注腹泻病,并针对不同人群采取不同防控措施。

Enrichment-ELISA for Detection of Salmonella typhi From Food and Water Samples

Objective Development of monoclonal antibody based sandwich enzyme linked immunosorbant assay （sELISA） for rapid detection of Salmonella enterica serovar typhi （S. typhi） from food and water samples and optimization of enrichment procedures for use with the developed sELISA to increase the detection sensitivity of the assay. Methods Spleen cells from BALB/c mice immunized with flagellin （H=d） antigen of S. typhi were fused with Sp2/0 myeloma cells. The hybridoma cell line specific to H=d antigen was established, characterized and ascites raised against one of these clones. The hyperimmune serum to flagellin antigen was raised in New Zealand White rabbits. An sELISA was developed using polyclonal antibody as capture and monoclonal antibody as detection antibody. To design the efficient culture strategies for use with the sELISA, different pre-enrichment and enrichment broths were evaluated. The media included buffered peptone water （BPW） and brain heart infusion broth for pre-enrichment and selenite F broth and Rappaport-Vassiliadis broth as enrichment broths. The developed sELISA with preceding enrichment step in BPW （Enrichment-ELISA） was evaluated in various food samples artificially inoculated with S. typhi bacteria. Various food （30） and water （35） samples collected from field were also tested by Enrichment-ELISA and culture method. Results Out of four specific clones to H=d antigen, one clone （# 2/56, IgG2a isotype） was used in sELISA. The sELISA had the detection limit of 10^4-10^5 cfu of S. typhi. Of the various broths used with sELISA, BPW was found to yield maximum ELISA values. Enrichment-ELISA, when tested in artificially inoculated food samples, generally, could detect 10^2 S. typhi cfu/mL within 10 h from various food rinses （meat, vegetable） and milk samples. After overnight enrichment in BPW, as less as 2 bacteria per 10 mL of milk, meat rinse, and chicken rinse could be detected. Only one of the field samples （water） gave false positive result by Enrichment-ELISA. Conclusion In comparison to culture, the Enrichment-ELISA is a rapid, sensitive, and specific method for detection of S. typhi from food or water samples. This method may be used as rapid screening procedure for environmental monitoring during outbreak situation.

Prevalence and antimicrobial resistance of non-typhoid Solmonella in military personnel,1988-2013

Objective:To describe the spanning 25 years data for the occurrence, magnitude, and trends regarding antimicrobial resistance of non-typhoidalSalmonella (NTS) isolated from non-immune travelers to Thailand participating in joint military operations.Methods:A total of 355 NTS isolates, obtained from 2052 fecal samples from US soldiers deployed for military maneuvers in Thailand during 1988-2013, were examined for NTS serogroup/serotypes and tested for antimicrobial susceptibility by disk diffusion to these 10 antibiotics:ampicillin, azithromycin (AZM), ciprofloxacin, colistin, gentamicin, kanamycin, nalidixic acid, streptomycin (STR), tetracycline (TET), and trimethoprim/sulfamethoxazole. Identified AZM-resistant NTS isolates were further evaluated for their minimal inhibitory concentration by the E-test method.Results:NTS infections accounted for 17.3％ (355/2052), including 11 serogroups and 50 different serotypes. The most prevalent serogroup wasSalmonella group C2-C3 (35.8％, 127/355) followed by groups B (21.1％, 75/355) and C1 (18.6％, 66/355). Identified serotypes includedSalmonellahadar (n=60),Salmonellarissen (n=45), andSalmonella blockley (n=34). Among the predominate serogroups, antimicrobial resistance was consistently high against TET (76.9％, 273/355) followed by STR (40.8％, 145/355). OneSalmonella senftenberg isolate demonstrated decreased ciprofloxacin susceptibility. Most isolates (94.6％) were resistant to one or more antimicrobials, and the most common multidrug resistance was TET-STR-nalidixic acid (11.5％, 41/355).Conclusions:The prevalence of NTS serotypes and the growing magnitude of antibiotic resistant bacteria isolated from deployed US military in Thailand are documented from 1988-2013. This study demonstrates the antibiotic resistance profiles, highlighting the effectiveness of AZM that is a first-line treatment for travelers to Southeast Asia. AZM-resistant NTS isolates are periodically observed over a 25-year period. Hence, the ongoing surveillance and prevalence efforts are required to monitor NTS resistant strains causing further treatment failure.