Co-occurrence of cfr-mediated linezolid-resistance in ST398 LA-MRSA and non-aureus staphylococci isolated from a pig farm

Linezolid resistance, mediated by the cfr gene, which confers resistant phenotypes to phenicols, lincosamides, oxazolidinones, pleuromutilins, and streptogramin A antimicrobials, has emerged in S. aureus and non-aureus staphylococci (NAS). Moreover, due to the transferable potential via plasmids, the spread of cfr among staphylococci is of great concern. In the present study, we investigated the prevalence of cfr-mediated linezolid resistance in ST398 methicillin-resistant S. aureus (MRSA) and NAS strains isolated from a pig farm. Among the 26 staphylococci isolates collected from a pig farm, 14 cfr-harboring ST398 MRSA and NAS (S. epidermidis, S. pasteuri, S. cohnii, and S. rostri) strains were resistant to linezolid and also carried the fexA gene. Comparative genome analysis of cfr-carrying linezolid-resistant ST398 MRSA and NAS (S. pasteuri, S. cohnii, and S. epidermidis) strains revealed that the segments harboring cfr in different staphylococcal strains showed ≥ 99 % sequence identity and the corresponding region containing the cfr, fexA, and Tn558 elements were located in a 38-kb plasmid, designated pSA12 of ST398 MRSA. These observations indicate that the cfr-carrying plasmids and/or fragments may be disseminated among staphylococci in a pig farm and possibly transmitted to staphylococci of human origin, subsequently posing a threat to public health. This is the first report of the co-existence of cfr in linezolid-resistant ST398 MRSA and NAS isolated from a pig farm in South Korea.

[Analysis on migration of HIV/AIDS cases and related factors in Liangshan Yi Autonomous Prefecture in Sichuan province, 2020]

Objective: To analyze the migration of the HIV/AIDS cases and related factors in Liangshan Yi autonomous prefecture (Liangshan). Methods: According to HIV/AIDS Comprehensive Response Information Management System of China Information System for Disease Control and Prevention, a total of 28 772 HIV/AIDS cases who had follow-up records in Liangshan in 2020 were included in the survey. The migration of the HIV/AIDS cases was described and the related factors were analyzed using multiple logistic regression models, and the migration destinations of the HIV/AIDS cases were mapped. Results: Among the 28 772 HIV/AIDS cases, 20.89% (6 010/28 772) had migration in 2020. Multivariate logistic regression analysis showed that among the HIV/AIDS cases, the migration related factors included being aged 15-24 years (compared with being aged 0-14 years, OR=2.74, 95%CI:2.04-3.69) and ethnic group (compared with Han ethnic group, OR=2.44, 95%CI:2.19-2.72), having education level of junior high school (compared with having education level of primary school or below, OR=1.25, 95%CI:1.14-1.38), being unmarried (compared with being married, OR=1.29, 95%CI:1.20-1.39), being engaged in business services (compared with being engaged in farming, OR=1.96, 95%CI:1.31-2.92), receiving antiviral treatment <1 year (compared with receiving antiviral treatment >3 years, OR=1.42, 95%CI:1.26-1.61), having recent CD4⁺T lymphocytes (CD4) counts >500 cells/μl (compared with having recent CD4 counts <200 cells/μl, OR=1.15, 95%CI:1.03-1.29). The geographical distribution maps showed that among all cities in Sichuan, Xichang (13.26%, 797/6 010) and Chengdu (10.12%,608/6 010) were the main migration destinations of the HIV/AIDS cases, and the provinces outside Sichuan where the HIV/AIDS cases would like to migrate to were mainly Guangdong (18.19%, 1 093/6 010) and Zhejiang provinces (7.67%, 461/6 010) in 2020. The HIV/AIDS cases who migrated where Liangshan, within Sichuan province, and to other provinces accounted for 27.67% (1 663/6 010), 15.34% (922/6 010) and 56.99% (3 425/6 010), respectively. Conclusions: More attention should be paid to the mobility characteristics and the classification management of HIV/AIDS cases according to their characteristics in Liangshan. Timely access to information on changes in the place of work and residence of HIV/AIDS cases should be warranted when they have migration. Good referrals and management for mobility of HIV/AIDS cases in different places should be made to reduce loss to follow-up and improving interventions.

Profiles of Non-aureus staphylococci in retail pork and slaughterhouse carcasses: prevalence, antimicrobial resistance, and genetic determinant of fusidic acid resistance

As commensal colonizers in livestock, there has been little attention on staphylococci, especially non-aureus staphylococci (NAS), contaminating meat production chain. To assess prevalence of staphylococci in retail pork and slaughterhouse carcass samples in Korea, we collected 578 samples from Korean slaughterhouses (n=311) and retail markets (n=267) for isolation of staphylococci and determined antimicrobial resistance phenotypes in all the isolates. The presence of and prevalence of fusB-family genes (fusB, fusC, fusD, and fusF) and mutations in fusA genes were examined in fusidic acid resistant isolates. A total of 47 staphylococcal isolates of 4 different species (Staphylococcus aureus, n=4; S. hyicus, n=1; S. epidermidis, n=10; Mammaliicoccus sciuri, n=32) were isolated. Fusidic acid resistance were confirmed in 9/10 S. epidermidis and all of the 32 M. sciuri (previously S. sciuri) isolates. Acquired fusidic acid resistance genes were detected in all the resistant strains; fusB and fusC in S. epidermidis and fusB/C in M. sciuri. Multi-locus sequence type analysis revealed that ST63 (n=10, 31%) and ST30 (n=8, 25%) genotypes were most prevalent among fusidic acid resistant M. sciuri isolates. In conclusion, the high prevalence of fusB-family genes in S. epidermidis and M. sciuri strains isolated from pork indicated that NAS might act as a reservoir for fusidic acid resistance gene transmissions in pork production chains.

[HBx promotes ubiquitination and degradation of ZO1 and increases the migration and invasion of liver cancer cells]

Objective: To study the effect of hepatitis B virus X protein (HBx) expression level on migration and invasion of zonula occludens protein-1 (ZO-1) in HepG2 liver cancer cells. Methods: Liver cancer cells were transfected with HBV full gene plasmid (pcDNA3.1-HBV1. 1 or pcDNA3.1-HBV1.3), empty plasmid (pcDNA3.1) and HBV-encoded protein plasmids (pHBc, pHBs, pHBp and pHBx), respectively. Western blot and RT-PCR were used to detect ZO1 protein and mRNA levels. Immunoprecipitation was used to detect transfected pHBx. Western blot was used to detect ZO1 ubiquitination levels. Transwell chambers were used to assess cell migration and invasion. Cell proliferation and lactate dehydrogenase assay was used to detect siRNA transfecting targeting ZO1. Flow cytometry was used to detect cell apoptosis and cycle. The data was compared between two and multiple groups by using an independent sample t-test and one-way analysis of variance. Results: Compared with the empty plasmid, ZO1 protein level in HepG2 cells after transiently transfected with pHBV1.1 and pHBV1.3 was decreased by 42.99% ± 6.8% and 55.0% 5 ± 4.56%, respectively, and their mRNA levels did not change significantly. ZO1 protein level in Huh7 cells was decreased by 17.46% ± 4.94% and 47.53% ± 3.38%, respectively. ZO1 protein level after transfection with pHBx was decreased by 47.02% ± 3.4%, while the ZO1 protein level after transfection with pHBc, pHBs and pHBp did not change significantly. ZO1 mRNA level was unaffected with pHBx transfection. ZO1 ubiquitin level and cell migration and invasion ability in HepG2 cells was significantly increased with transfected pHBx. HepG2 cells proliferation, apoptosis and cycle after transfection with ZO1-targeted siRNA did not change significantly, but the migration and invasion ability were significantly increased. Conclusion: HBx can increase the migration and invasion of liver cancer cells by promoting the ubiquitination and degradation of ZO1 protein level.

[Causal inference methods and its application in the study of health effects of air pollution]

The adverse health effects of air pollution remains a daunting public health problem globally. The research of the health effects of air pollution provides important evidence for ambient air quality standard establishments and air pollution interventions. In recent years, causal inference has been gradually introduced into the observational study of environmental epidemiology, which provides more statistical method options for the study of causal relationships between air pollution and population health effects. Controlling confounders in observational studies is a major challenge for causal inference. This study introduces the causal inference methods for the identification and control of confounding factors currently used in the study of air pollution and population health effects, in order to provide methodological reference and basis for the causal inference study of air pollution and population health effects in China.

Type I Interferons Are Involved in the Intracellular Growth Control of Mycobacterium abscessus by Mediating NOD2-Induced Production of Nitric Oxide in Macrophages

Mycobacterium abscessus (MAB) is one of the rapidly growing, multidrug-resistant non-tuberculous mycobacteria (NTM) causing various diseases including pulmonary disorder. Although it has been known that type I interferons (IFNs) contribute to host defense against bacterial infections, the role of type I IFNs against MAB infection is still unclear. In the present study, we show that rIFN-β treatment reduced the intracellular growth of MAB in macrophages. Deficiency of IFN-α/β receptor (IFNAR) led to the reduction of nitric oxide (NO) production in MAB-infected macrophages. Consistently, rIFN-β treatment enhanced the expression of iNOS gene and protein, and NO production in response to MAB. We also found that NO is essential for the intracellular growth control of MAB within macrophages in an inhibitor assay using iNOS-deficient cells. In addition, pretreatment of rIFN-β before MAB infection in mice increased production of NO in the lungs at day 1 after infection and promoted the bacterial clearance at day 5. However, when alveolar macrophages were depleted by treatment of clodronate liposome, rIFN-β did not promote the bacterial clearance in the lungs. Moreover, we found that a cytosolic receptor nucleotide-binding oligomerization domain 2 (NOD2) is required for MAB-induced TANK binding kinase 1 (TBK1) phosphorylation and IFN-β gene expression in macrophages. Finally, increase in the bacterial loads caused by reduction of NO levels was reversed by rIFN-β treatment in the lungs of NOD2-deficient mice. Collectively, our findings suggest that type I IFNs act as an intermediator of NOD2-induced NO production in macrophages and thus contribute to host defense against MAB infection.

Role of the Staphylococcus aureus Extracellular Loop of GraS in Resistance to Distinct Human Defense Peptides in PMN and Invasive Cardiovascular infections

GraS is a membrane sensor in Staphylococcus aureus that induces mprF and dltABCD expression to alter the surface positive charge upon exposure to cationic human defense peptides (HDPs). The sensing domain of GraS likely resides in the 9-residue extracellular loop (EL). In this study, we assessed a hospital-acquired methicillin-resistant S. aureus (HA-MRSA) strain (COL) for the specific role of two distinct EL mutations: F38G (bulk) and D/35/37/41K (charged inversion). Activation of mprF by polymyxin B (PMB) was reduced in the D35/37/41K mutant versus the D35/37/41G mutant, correlating with reduced surface positive charge; in contrast, these effects were less prominent in the F38G mutant but still lower than those in the parent. These data indicated that both electrostatic charge and steric bulk of the EL of GraS influence induction of genes impacting HDP resistance. Using mprF expression as a readout, we confirmed GraS signaling was pH dependent, increasing as pH was lowered (from pH 7.5 down to pH 5.5). In contrast to PMB activation, reduction of mprF was comparable at pH 5.5 between the P38G and D35/37/41K point mutants, indicating a mechanistic divergence between GraS activation by acidic pH versus cationic peptides. Survival assays in human blood and purified polymorphonuclear leukocytes (PMNs) revealed lower survival of the D35/37/41K mutant versus the F38G mutant, with both being lower than that of the parent. Virulence studies in the rabbit endocarditis model mirrored whole blood and PMN killing assay data described above. Collectively, these data confirmed the importance of specific residues within the EL of GraS in conferring essential bacterial responses for MRSA survival in infections.

Profiles of coagulase-positive and -negative staphylococci in retail pork: prevalence, antimicrobial resistance, enterotoxigenicity, and virulence factors

Objective

The present study aimed to investigate the occurrence and species of coagulase-positive staphylococci (CoPS) and coagulase-negative staphylococci (CoNS) in retail pork meat samples collected during nationwide monitoring. The staphylococcal isolates were characterized for antimicrobial and zinc chloride resistance and enterotoxigenic potential.

Methods

A total of 260 pre-packaged pork meat samples were collected from 35 retail markets in 8 provinces in Korea for isolation of staphylococci. Antimicrobial and zinc chloride resistance phenotypes, and genes associated with the resistance phenotypes were determined on the isolates. Furthermore, the presence and distribution of 19 staphylococcal enterotoxin (SE) genes and enterotoxin-like genes among the pork-associated staphylococci were determined by multiplex polymerase chain reaction-based assays using the specific primer sets.

Results

A total of 29 staphylococcal strains (29/260, 11.1%) were isolated from samples of retail pork meat, 24 (83%) of which were CoNS. The four CoNS species identified were S. saprophyticus (n = 16, 55%), S. sciuri (n = 3, 10%), S. warneri (n = 3, 10%), and S. epidermidis (n = 2, 7%). Among the 29 isolates, four methicillin-resistant CoNS (MR-CoNS; three S. sciuri and one S. epidermidis) and one methicillin-resistant CoPS (MR-CoPS; one S. aureus) were identified. In addition, a relatively high level of tetracycline (TET) resistance (52%) was confirmed in CoNS, along with a predominant distribution of tet(K). The most prevalent SEs were sep (45%), and sen (28%), which were carried by 81% of S. saprophyticus.

Conclusion

These findings suggest that CoNS, especially S. saprophyticus strains, in raw pork meat could be a potential risk factor for staphylococcal food poisoning (SFP), and therefore, requires further investigation to elucidate the role of SEls in SFP and virulence of the pathogen. Our results also suggest that CoNS from raw pork meat may act as a source for transmission of antimicrobial resistance genes such as staphylococcal cassette chromosome mec and tet(K).

Towards the formulation of rural sewage discharge standards in China

In China, most rural areas lack specific sewage discharge standards. Even though China governments proposed a series of local standards, the most of the existing China's rural sewage discharge standards are still similar to urban discharge standards. This research analyses comprehensively the data of rural sewage discharge standards in the 31 provinces and cities in China in terms of grade and indicator, and forms a structural framework for the formulation and revised standards in rural areas of China. In the formulation, we use 2 components, end-use and environmental capacity, to reflect local characteristics of the grades and indicators, and also propose the methods of combining discharge standards with relevant water quality standards to save energy. And we also use the mathematical model to illustrate environmental capacity in different regions. The paper shows the great potential in guiding the design of discharge standards formulation and revision for rural wastewater treatment in China and other developing countries as well.

Genomic Information on Linezolid-Resistant Sequence-Type 398 Livestock-Associated Methicillin-Resistant Staphylococcus aureus Isolated from a Pig

The frequent occurrence of sequence-type 398 (ST398) livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) in pigs has become a major public health concern owing to the increased zoonotic potential of the pathogen. Recently, a novel oxazolidinone resistance gene, chloramphenicol-florfenicol resistant (cfr), conferring multiresistance phenotypes to phenicols, lincosamides, oxazolidinones, pleuromutilins, and streptogramin A (PhLOPS_A), has been found among ST398 LA-MRSA strains isolated from pigs. In this study, we report the first in silico genome analysis of a linezolid-resistant ST398 LA-MRSA strain, designated PJFA-521M, recovered from a pig in Korea. Genomic analyses revealed that the presence of the cfr gene was responsible for the observed linezolid resistance in the PJFA-521M strain. Moreover, newer antimicrobial resistance genes, such as the dfrG, aadE, spw, lsa(E), lnu(B), and fexA genes, were found in the PJFA-521M strain. In addition to the genetic elements for antimicrobial resistance, the carriage of various virulence genes for adherence, invasion, and immunomodulation was identified in the genome, especially within several mobile genetic elements (MGEs). The presence of multiple antimicrobial resistance genes and virulence genes on MGEs in the genome of a linezolid-resistant ST398 LA-MRSA should raise awareness regarding the use of other antimicrobial agents in pig farms and may also provide selective pressure for the prevalence of the cfr gene and the associated multidrug-resistant phenotype.

[Design and clinical application of a combined shoulder abduction orthosis for post-burn treatment]

Cicatricial contracture is likely to occur at the deep burn wound under the armpits after healing, which results in limitation of shoulder abduction and seriously affects the function of upper limbs of patients. Wearing shoulder abduction orthosis is an effective intervention method for cicatricial contracture under the armpits, but the adjustable shoulder abduction orthosis commonly used clinically at present is limited in the adjustable range, and the customized static orthosis can only maintain the corresponding angle of shoulder abduction. Besides, the above two orthosis can only have the function of unilateral extention, and they are time-consuming for patients with need of bilateral extension. Aiming at the problems mentioned above, a combined shoulder abduction orthosis was designed by the Tongren Hospital of Wuhan University & Wuhan Third Hospital. The low temperature thermoplastic sheet was cut, shaped, and assembled according to the patient's measurement data of abdomen, upper arm, and lumbar to prepare the combined shoulder abduction orthosis. This abduction orthosis can not only extend the cicatrix contracture under the armpits progressively and extensively, so as to effectively prevent the cicatricial contracture under the armpits, but also can select unilateral or bilateral extension based on the contracture limits for shoulder abduction, thus saving time for both medical workers and patients in relevant treatment.

[Role of cardiac magnetic resonance imaging in myocarditis patients with biopsy negative: a retrospective case series study]

Objective: To analyze the cardiac magnetic resonance (CMR) imaging feature of clinically diagnosed myocarditis patients with negative endocardial biopsy (EMB) results, and to further demonstrate the diagnostic value of CMR in these patients. Methods: This was a retrospective case series study. Fourteen patients, who were clinically diagnosed as myocarditis according to 2013 European Society of Cardiology (ESC) clinical diagnostic criteria for myocarditis, but with negative EMB results, were enrolled. All patients underwent CMR examinations. The morphological, functional and histological changes of the heart were assessed based on black blood sequence, cine sequence, T2W-STIR sequence and contrast agent late gadolinium enhancement,(LGE). Results: There were 10 males and 4 females in this cohort, the age was (25.6±13.2) years. The interval between symptom onset and CMR was 21 (13, 60) days, and the interval between symptom onset and EMB was 19 (9, 40) days. There were 13 patients with abnormal CMR results including myocardial oedema, fibrosis, decreased ejection fraction, pericardial effusion or increased cardiac chamber dimension. Nine out of 14 patients had CMR morphological and/or functional abnormalities, including 1 case of left atrium enlargement, 1 case of left ventricle enlargement, 3 cases of right ventricle enlargement, 4 cases of increased left ventricular end diastolic volume index. Left ventricular ejection fraction was<50% in three cases, right ventricular ejection fraction was<40% in 5 cases, and pericardial effusion depth>3 mm was detected in 3 cases. Of the 14 patients, 11 had histological changes, of which 6 had T2 ratio≥2. Among the 10 patients (10/14) with positive LGE, the most common patterns were subepicardial LGE of the lateral wall and/or midwall LGE of the septum (n=9); 2 cases showed extensively subendocardial LGE of the left ventricular wall. No LGE involved in the right ventricular wall in the whole cohort. Conclusion: CMR plays a complementary role in the diagnosis of myocarditis in clinically diagnosed myocarditis patients with negative EMB findings.

Profiles of coagulase-positive and -negative staphylococci in retail pork: prevalence, antimicrobial resistance, enterotoxigenicity, and virulence factors

Objective

The present study aimed to investigate the occurrence and species of coagulase-positive staphylococci (CoPS) and coagulase-negative staphylococci (CoNS) in retail pork meat samples collected during nationwide monitoring. The staphylococcal isolates were characterized for antimicrobial and zinc chloride resistance and enterotoxigenic potential.

Methods

A total of 260 pre-packaged pork meat samples were collected from 35 retail markets in 8 provinces in Korea for isolation of staphylococci. Antimicrobial and zinc chloride resistance phenotypes, and genes associated with the resistance phenotypes were determined on the isolates. Furthermore, the presence and distribution of 19 staphylococcal enterotoxin (SE) genes and enterotoxin-like genes among the pork-associated staphylococci were determined by multiplex PCR-based assays using the specific primer sets.

Results

A total of 29 staphylococcal strains (29/260, 11.1%) were isolated from samples of retail pork meat, 24 (83%) of which were CoNS. The four CoNS species identified were S. saprophyticus (n = 16, 55%), S. sciuri (n = 3, 10%), S. warneri (n = 3, 10%), and S. epidermidis (n = 2, 7%). Among the 29 isolates, four methicillin-resistant CoNS (MR-CoNS; three S. sciuri and one S. epidermidis) and one methicillin-resistant CoPS (MR-CoPS; one S. aureus) were identified. In addition, a relatively high level of tetracycline (TET) resistance (52%) was confirmed in CoNS, along with a predominant distribution of tet(K). The most prevalent SEs were sep (45%) and sen (28%), which were carried by 81% of S. saprophyticus.

Conclusion

These findings suggest that CoNS, especially S. saprophyticus strains, in raw pork meat could be a potential risk factor for staphylococcal food poisoning (SFP), and therefore, requires further investigation to elucidate the role of SEls in SFP and virulence of the pathogen. Our results also suggest that CoNS from raw pork meat may act as a source for transmission of antimicrobial resistance genes such as SCCmec and tet(K).

Species Distribution, Antimicrobial Resistance, and Enterotoxigenicity of Non-aureus Staphylococci in Retail Chicken Meat

Non-aureus staphylococci (NAS), including coagulase-negative staphylococci, have emerged as important causes of opportunistic infections in humans and animals and a potential cause of staphylococcal food poisoning. In this study, we investigated (i) the staphylococcal species profiles of NAS in in retail chicken meat, (ii) the phenotypic and genotypic factors associated with antimicrobial resistance in the NAS isolates, and (iii) the prevalence of classical and newer staphylococcal enterotoxin (SE) genes. A total of 58 NAS of nine different species were isolated from retail raw chicken meat samples. The occurrence of multidrug resistance in the NAS, particularly S. agnetis and S. chromogenes, with high resistance rates against tetracycline or fluoroquinolones were confirmed. The tetracycline resistance was associated with the presence of tet(L) in S. chromogenes and S. hyicus or tet(K) in S. saprophyticus. The occurrence of fluoroquinolone resistance in S. agnetis and S. chromogenes was usually associated with mutations in the quinolone resistance determining regions (QRDR) of gyrA and parC. In addition, the frequent presence of SE genes, especially seh, sej, and sep, was detected in S. agnetis and S. chromogenes. Our findings suggest that NAS in raw chicken meat can have potential roles as reservoirs for antimicrobial resistance and enterotoxin genes.

Growth and saturation of stimulated Raman scattering in two overlapping laser beams

Two-dimensional particle-in-cell simulations are presented of the linear and nonlinear developments of stimulated Raman scattering in two overlapping laser beams. The development of the most unstable mode in the linear stage is consistent with a previous paper [C. Z. Xiao et al., Phys. Plasmas 26, 062109 (2019)PHPAEN1070-664X10.1063/1.5096850] where SL mode (two beams share a common scattered light) is dominant in the overlapping region. This mode is enhanced with plasma density and correlation of beam polarizations. When lasers are cross-polarized, it backs to the single-beam Raman backscattering with weak intensity. Trapping-induced nonlinear frequency shift leads to the saturation of SL mode by detuning the coupling and broadening the spectrum. An interesting result that SL mode becomes stronger as the incidence angle increases is contrary to the theoretical prediction and it is a consequence of less efficient saturation in the nonlinear stage.

[Establishment and clinical testing of pancreatic cancer Faster R-CNN AI system based on fast regional convolutional neural network]

Objective: To investigate the effectiveness of an enhanced CT automatic recognition system based on Faster R-CNN for pancreatic cancer and its clinical value. Methods: In this study, 4 024 enhanced CT imaging sequences of 315 patients with pancreatic cancer from January 2013 to May 2016 at the Affiliated Hospital of Qingdao University were collected retrospectively, and 2 614 imaging sequences were input into the faster R-CNN system as training dataset to create an automatic image recognition model, which was then validated by reading 1 410 enhanced CT images of 135 cases of pancreatic cancer.In order to identify its effectiveness, 3 750 CT images of 150 patients with pancreatic lesions were read and a followed-up was carried out.The accuracy and recall rate in detecting nodules were recorded and regression curves were generated.In addition, the accuracy, sensitivity and specificity of Faster R-CNN diagnosis were analyzed, the ROC curves were generated and the area under the curves were calculated. Results: Based on the enhanced CT images of 135 cases, the area under the ROC curve was 0.927 calculated by Faster R-CNN. The accuracy, specificity and sensitivity were 0.902, 0.913 and 0.801 respectively.After the data of 150 patients with pancreatic cancer were verified, 893 CT images showed positive and 2 857 negative.Ninety-eight patients with pancreatic cancer were diagnosed by Faster R-CNN.After the follow-up, it was found that 53 cases were post-operatively proved to be pancreatic ductal carcinoma, 21 cases of pancreatic cystadenocarcinoma, 12 cases of pancreatic cystadenoma, 5 cases of pancreatic cyst, and 7 cases were untreated.During 5 to 17 months after operation, 6 patients died of abdominal tumor infiltration, liver and lung metastasis.Of the 52 patients who were diagnosed negative by Faster R-CNN, 9 were post-operatively proved to be pancreatic ductal carcinoma. Conclusion: Faster R-CNN system has clinical value in helping imaging physicians to diagnose pancreatic cancer.

Unveiling the Crucial Role of Type IV Secretion System and Motility of Helicobacter pylori in IL-1β Production via NLRP3 Inflammasome Activation in Neutrophils

Helicobacter pylori is a gram-negative, microaerophilic, and spiral-shaped bacterium and causes gastrointestinal diseases in human. IL-1β is a representative cytokine produced in innate immune cells and is considered to be a key factor in the development of gastrointestinal malignancies. However, the mechanism of IL-1β production by neutrophils during H. pylori infection is still unknown. We designed this study to identify host and bacterial factors involved in regulation of H. pylori-induced IL-1β production in neutrophils. We found that H. pylori-induced IL-1β production is abolished in NLRP3-, ASC-, and caspase-1/11-deficient neutrophils, suggesting essential role for NLRP3 inflammasome in IL-1β response against H. pylori. Host TLR2, but not TLR4 and Nod2, was also required for transcription of NLRP3 and IL-1β as well as secretion of IL-1β. H. pylori lacking cagL, a key component of the type IV secretion system (T4SS), induced less IL-1β production in neutrophils than did its isogenic WT strain, whereas vacA and ureA were dispensable. Moreover, T4SS was involved in caspase-1 activation and IL-1β maturation in H. pylori-infected neutrophils. We also found that FlaA is essential for H. pylori-mediated IL-1β production in neutrophils, but not dendritic cells. TLR5 and NLRC4 were not required for H. pylori-induced IL-1β production in neutrophils. Instead, bacterial motility is essential for the production of IL-1β in response to H. pylori. In conclusion, our study shows that host TLR2 and NLRP3 inflammasome and bacterial T4SS and motility are essential factors for IL-1β production by neutrophils in response to H. pylori.

Occurrence and Characteristics of Methicillin-Resistant and -Susceptible Staphylococcus aureus Isolated from the Beef Production Chain in Korea

The emergence and persistence of methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) in livestock animals have been reported as a potential risk factor for transmission to humans. In this study, we investigated the nationwide prevalence and characteristics of MRSA and MSSA in the Korean beef production system, including retail markets, slaughterhouses, and cattle farms. From a total of 1,285 samples, only 5 MRSA strains were isolated: from a farmer (1 ST72 MRSA), a carcass sample from a slaughterhouse (1 ST72 MRSA), and beef cattle (3 ST5 MRSA). In addition, 11 MSSA strains were isolated from beef cattle (n=3), humans (1 farmer, 1 slaughterhouse worker, and 4 retail market workers), and carcass samples (n=1) and slaughterhouse environment (n=1). Although the prevalence of MRSA and MSSA in beef cattle was much lower than that reported in pigs, 5/5 MRSA and 2/11 MSSA strains displayed multiple drug resistance (MDR) phenotypes. Unlike the swine-associated MRSA, no correlation was found between tetracycline/zinc resistance and MDR phenotype. However, MRSA strains had an identical set of staphylococcal enterotoxins and exhibited enhanced levels of resistance to antimicrobial peptides (PMAP-36 and LL-37) compared to the MSSA strains. In conclusion, continued and systemic surveillance of livestock, meat products, and humans in close contact with livestock/meat products is necessary to prevent the transmission of MRSA and MSSA to humans.