Prevalence and Genetic Characterization of Methicillin-Resistant Staphylococcus aureus Isolated from Pigs in Japan.

We investigated the prevalence of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) in pig slaughterhouses from 2018 to 2022 in Japan and the isolates were examined for antimicrobial susceptibility and genetic characteristics by whole-genome analysis. Although the positive LA-MRSA rates on farms (29.6%) and samples (9.9%) in 2022 in Japan remained lower than those observed in European countries exhibiting extremely high rates of confirmed human LA-MRSA infections, these rates showed a gradually increasing trend over five years. The ST398/t034 strain was predominant, followed by ST5/t002, and differences were identified between ST398 and ST5 in terms of antimicrobial susceptibility and the resistance genes carried. Notably, LA-MRSA possessed resistance genes toward many antimicrobial classes, with 91.4% of the ST398 strains harboring zinc resistance genes. These findings indicate that the co-selection pressure associated with multidrug and zinc resistance may have contributed markedly to LA-MRSA persistence. SNP analysis revealed that ST398 and ST5 of swine origin were classified into a different cluster of MRSA from humans, showing the same ST in Japan and lacking the immune evasion genes (scn, sak, or chp). Although swine-origin LA-MRSA is currently unlikely to spread to humans and become a problem in current clinical practice, preventing its dissemination requires using antimicrobials prudently, limiting zinc utilization to the minimum required nutrient, and practicing fundamental hygiene measures.

Characterization of Actinobacillus pleuropneumoniae isolated from pigs in Japan using whole genome sequencing.

We conducted whole-genome sequencing to investigate the serotypes, the presence of virulence and antimicrobial resistance genes, and the genetic relationships among isolates of Actinobacillus. pleuropneumoniae derived from diseased pigs. Serotype 2 (71.2%) was the most common, but the prevalence of serotypes 6 (13.6%) and 15 (6.8%) increased. Existing vaccines are considered ineffective on the isolates belonging to serotypes 6 and 15. The phylogenetic tree based on core genome single nucleotide polymorphisms showed that the isolates were clustered by serotype. Of the isolates, 62.5% did not have an antimicrobial resistance gene, including a florfenicol resistance gene, but 32.2% had a tetracycline resistance gene. The antimicrobial resistant phenotype and genotype were almost identical. The plasmid-derived contigs harbored resistance genes of aminoglycosides, tetracyclines, ß-lactams, phenicols, or sulfonamides. It has been suggested that isolates with different genetic properties from vaccine strains are circulating; however, antimicrobial resistance may not be widespread.

Diagnostic approach for mediastinal masses with radiopathological correlation.

PURPOSE: Mediastinal masses have various histopathological and radiological findings. Although lymphoma is the most common type of tumor, thymic epithelial and neurogenic tumors are common in adults and children, respectively, but several other types are difficult to distinguish. No previous review has simply and clearly shown how to differentiate mediastinal masses. METHOD: We conducted a review of the latest mediastinal classifications and mass differentiation methods, with a focus on neoplastic lesions. Both older and recent studies were searched, and imaging and histopathological findings of mediastinal masses were reviewed. Original simple-to-use differentiation flowcharts are presented. RESULTS: Assessing localizations and internal characteristics is very important for mediastinal mass differentiation. The mass location and affected organ/tissue should be accurately assessed first, followed by more qualitative diagnosis, and optimization of the treatment strategy. In 2014, the International Thymic Malignancy Interest Group presented a new mediastinal clinical classification. In this classification, mediastinal masses are categorized into three groups according to location: prevascular (anterior)-, visceral (middle)-, and paravertebral (posterior)-compartment masses. Then, the internal characteristics and functional images are evaluated. CONCLUSIONS: Differentiation of mediastinal masses is very difficult. However, if typical imaging findings and clinical characteristics are combined, reasonable differentiation is possible. In each patient, proper differential diagnosis may contribute to better treatment selection.

Transcatheter Arterial Embolization for Intramammary Hemorrhage Caused by a Seat Belt Injury: Case Series Including Experience with N-butyl-2-cyanoacrylate.

In this study, we report two cases of transcatheter arterial embolization for intramammary hemorrhage caused by seat belt injuries. All patients were female drivers involved in traffic accidents. In each case, we accessed the hemorrhage through the left brachial artery and embolized the perforating branch of the left internal mammary artery with N-butyl-2-cyanoacrylate, obtaining effective hemostasis. Transcatheter arterial embolization is considered effective for breast hemorrhage because of rare but dangerous seat belt injuries.

Molecular epidemiology of methicillin-resistant Staphylococcus aureus isolated from pigs in Japan.

Methicillin-resistant Staphylococcus aureus (MRSA) is the leading cause of infection in hospitalized patients and can be prevalent in humans and various animal species. In European countries, MRSA isolates belonging to clonal complex 398 have been detected at high rates in pigs. However, the prevalence of MRSA in pigs and farm environments in Japan remains unclear. MRSA isolates were obtained from pigs in slaughterhouses, diseased pigs on farms, imported breeding pigs, and farm dust. We conducted whole-genome sequencing (WGS) and analyzed the molecular epidemiological relationship between these MRSA isolates using core genome multilocus sequence typing (cgMLST). The prevalence rates of MRSA among pigs in slaughterhouses, diseased pigs on farms, imported breeding pigs, and farm dust were 5.2 %, 3.4 %, 28.8 %, and 0.06 %, respectively. ST 398 isolates that classified as ST398/t034 were isolated from pigs from all sources. The results of cgMLST showed that ST398/t034 isolates originating from domestic pigs clustered into the same cluster as the isolates from imported breeding pigs. However, some clusters only included isolates of domestic pig origin. Most MRSA isolates in this study carried resistance genes for aminoglycosides, ß-lactams, macrolides, tetracyclines, and zinc. None of the MRSA isolates in this study harbored Panton-Valentine leukocidin toxin genes. Molecular epidemiological analysis suggested a relationship between isolates from slaughter pigs and imported breeding pigs and the presence of MRSA isolates of domestic origin. However, more data are needed for elucidation of the origin of these MRSA variants in the pig industry in Japan.

Tracheobronchitis in patients with diffuse wall thickening: Three case reports.

We herein report the cases of three patients with chest symptoms or fever and diffuse wall thickening of the trachea and main bronchi on chest CT. They were diagnosed with various causes of inflammations of the trachea and main bronchi using bronchial or tracheal biopsy specimens and flexible bronchoscopy.

Bochdalek hernia with liver herniation.

Bochdalek hernia with liver herniation is rare and mimics a pulmonary mass. This case was hospitalized for masses found in the lower field of the right lung on a chest radiograph. The patient was diagnosed with Bochdalek hernia with liver herniation with three-dimensional images created from thoracoabdominal-enhanced computed tomography.

Correlation of minimum inhibitory concentrations between human and animal antimicrobials against Escherichia coli isolated from livestock.

We analyzed the correlation between minimum inhibitory concentrations (MICs) of antimicrobials used in humans and those used in animals to enable comparison of antimicrobial susceptibility between Escherichia coli isolated from humans and those from animals. We compared the following pairs of MIC data: piperacillin (PIPC) to ampicillin (ABPC), amikacin (AMK) to kanamycin (KM), minocycline (MINO) to oxytetracycline (OTC), and levofloxacin (LVFX) to enrofloxacin (ERFX) using 103 isolates of E. coli from healthy livestock (cattle, pigs, broiler chickens, and layer chickens). Kappa analysis of the agreement for resistance and susceptibility between PIPC and ABPC, AMK and KM, MINO and OTC, and LVFX and ERFX showed almost perfect (κ = 0.81), slight (κ = 0.12), fair (κ = 0.37), and moderate (κ = 0.46) agreement, respectively. Within the antimicrobial pairs, all isolates resistant to the human antimicrobial were also resistant to the veterinary antimicrobial. However, there was less agreement within the pairs for those isolates that were sensitive to the human antimicrobial. The percentage agreement for susceptibility, defined as the percentage of isolates sensitive to both antimicrobials compared with isolates sensitive to both antimicrobials, as well as those sensitive only to the human antimicrobial, was 89.9%, 87.3%, 64.0%, and 89.9% for PIPC and ABPC, AMK and KM, MINO and OTC, and LVFX and ERFX, respectively. Our results suggest that the possibility of missing the resistance for antimicrobials used in human medicine by examining MICs for the equivalent antimicrobials used in veterinary medicine is low.

Comparative Genomic Analysis of Third-Generation-Cephalosporin-Resistant Escherichia coli Harboring the blaCMY-2-Positive IncI1 Group, IncB/O/K/Z, and IncC Plasmids Isolated from Healthy Broilers in Japan.

The off-label use of third-generation cephalosporins (3GCs) during in ovo vaccination or vaccination of newly hatched chicks has been a common practice worldwide. CMY-2-producing Escherichia coli strains have been disseminated in broiler chicken production. The objective of this study was to determine the epidemiological linkage of blaCMY-2-positive plasmids among broilers both within and outside Japan, because the grandparent stock and parent stock were imported into Japan. We examined the whole-genome sequences of 132 3GC-resistant E. coli isolates collected from healthy broilers during 2002 to 2014. The predominant 3GC resistance gene was blaCMY-2, which was detected in the plasmids of 87 (65.9%) isolates. The main plasmid replicon types were IncI1-Iγ (n = 21; 24.1%), IncI (n = 12; 13.8%), IncB/O/K/Z (n = 28; 32.2%), and IncC (n = 22; 25.3%). Those plasmids were subjected to gene clustering, network analyses, and plasmid multilocus sequence typing (pMLST). The chromosomal DNA of isolates was subjected to MLST and single-nucleotide variant (SNV)-based phylogenetic analysis. MLST and SNV-based phylogenetic analysis revealed high diversity of E. coli isolates. The sequence type 429 (ST429) cluster harboring blaCMY-2-positive IncB/O/K/Z was closely related to isolates from broilers in Germany harboring blaCMY-2-positive IncB/O/K/Z. pST55-IncI, pST12-IncI1-Iγ, and pST3-IncC were prevalent in western Japan. pST12-IncI1-Iγ and pST3-IncC were closely related to plasmids detected in E. coli isolates from chickens in North America, whereas 26 IncB/O/K/Z types were related to those in Europe. These data will be useful to reveal the whole picture of transmission of CMY-2-producing bacteria inside and outside Japan.

Evaluation of the relationship between the minimum inhibitory concentration of ceftiofur and third-generation cephalosporins in Escherichia coli isolates from food-producing animals.

To enable future comparison of the antimicrobial susceptibility data between bacteria obtained from animals and humans, it is necessary to compare the relationships between minimum inhibitory concentrations (MICs) of veterinary and human medicine. We evaluated the relationship between the MIC of ceftiofur (CTF) and the MICs of other third-generation cephalosporins (TGCs): cefotaxime (CTX), cefpodoxime (CPDX), and ceftazidime (CAZ), determined by the broth microdilution method using 118 cefazolin-resistant Escherichia coli isolates from food-producing animals. Using the Clinical and Laboratory Standards Institute criteria, very major classification errors were observed only in CAZ (17.8%, 21 of 118); major and minor errors were observed in all TGCs (CTX: 0.8% [1 of 118] and 9.3% [11 of 118]; CPDX: 9.3% [11 of 118] and 6.8% [8 of 118]; CAZ: 2.5% [3 of 118] and 9.3% [11 of 118], respectively). The Spearman correlation coefficients between the MICs of CTF and CTX, CPDX, and CAZ were 0.765, 0.731, and 0.306, respectively. The sensitivity and specificity values were 100.0% and 81.8% for CTX, 99.0% and 27.3% for CPDX, and 76.0% and 86.4% for CAZ compared with CTF. The C-statistic was 0.978 for CTF and CTX, 0.953 for CPDX, and 0.798 for CAZ. For the TGCs evaluated in our study, testing for CTX susceptibility results showed the highest correlation with the results given when testing for CTF susceptibility.

Prevalence of Colistin Resistance Gene mcr-1 and Absence of mcr-2 in Escherichia coli Isolated from Healthy Food-Producing Animals in Japan.

We screened mcr-1 and mcr-2 genes in 9,306 Escherichia coli strains isolated from healthy animals in the Japanese Veterinary Antimicrobial Resistance Monitoring (JVARM) system. mcr-1 was detected in 39 strains (5, 20, and 14 strains isolated from cattle, swine, and broilers, respectively), whereas mcr-2 was not detected. mcr-2 was also not detected with the investigation sequence homology search against our curated GenEpid-J database.

Molecular Typing of Fluoroquinolone-Resistant Campylobacter jejuni Isolated from Broilers in Japan Using Multilocus Sequence Typing and Pulsed-Field Gel Electrophoresis.

Fluoroquinolone-resistant Campylobacter jejuni isolates from broilers in Japan were characterized using multilocus sequence typing and pulsed-field gel electrophoresis (PFGE) in order to elucidate the genetic relationship between these strains. Forty-three of the isolates were classified into 20 sequence types and were clustered into 21 PFGE types with 70% similarity. The most dominant clonal complex (CC) was CC-21 (41.9%). Diverse PFGE patterns were observed within the same CC, but the combined analysis of PFGE type and CC revealed that the strains with the same combination were isolated from the same district or neighboring districts. On the other hand, strains with the same combination pattern were also isolated from geographically distant districts. Our results elucidate two possible reasons for the prevalence of fluoroquinolone-resistant C. jejuni among broiler farms: (1) the resistant C. jejuni is clonally disseminated within the limited area, and (2) susceptible C. jejuni acquired fluoroquinolone resistance during the use of fluoroquinolone on the farms.

Decreased Resistance to Broad-Spectrum Cephalosporin in Escherichia coli from Healthy Broilers at Farms in Japan After Voluntary Withdrawal of Ceftiofur.

The high prevalence of broad-spectrum cephalosporin (BSC) resistance in Escherichia coli isolates from healthy broilers at farms is a source of grave concern in Japan. In an effort to solve this problem, the off-label use of ceftiofur (CTF) at hatcheries was voluntarily withdrawn around March 2012. The objective of this study was to assess the effect of the voluntary withdrawal on the prevalence of BSC resistance in E. coli from healthy broilers at farms. A total of 693 E. coli isolates collected from 362 fecal samples of healthy broilers at farms between 2010 and 2013 were examined to determine their antimicrobial resistance profiles and ß-lactamase genes. ß-Lactamase genes were characterized by polymerase chain reaction and sequencing. BSC resistance was detected in 84 of the 693 E. coli isolates (12.1%) from healthy broilers between 2010 and 2013. The percentage of BSC-resistant E. coli isolates was significantly decreased: from 16.4% (32/195) in 2010 and 16.8% (27/161) in 2011 to 9.2% (19/206) in 2012 and 4.6% (6/131) in 2013 (2010 versus 2012: p=0.024, 2010 versus 2013: p=0.001, 2011 versus 2012: p=0.038, and 2011 versus 2013: p=0.001). Regarding ß-lactamase genes, 58 of the 84 BSC-resistant E. coli isolates (69.0%) harbored blaCMY-2. The prevalence of BSC resistance in E. coli isolated from healthy broilers at farms was markedly decreased within a year after the voluntary withdrawal from CTF use at hatcheries. This indicates that BSC resistance in E. coli isolates from broilers could be controlled by restricting the use of CTF at the hatchery level.

Diagnostic challenges of tuberculous lymphadenitis using polymerase chain reaction analysis: a case study.

This report presents a case of tuberculous lymphadenitis that was difficult to diagnose using polymerase chain reaction analysis. An 80-year-old Japanese female was hospitalized due to swollen cervical lymph nodes. Her lymph node tests revealed paradoxical polymerase chain reaction results. Polymerase chain reaction analysis of two biopsy tissues using the Cobas TaqMan revealed a positive result for Mycobacterium avium and a negative result for Mycobacterium tuberculosis. However, polymerase chain reaction analysis of a cultured colony of acid-fast bacteria from biopsy tissue using the Cobas TaqMan and an alternative polymerase chain reaction analysis of biopsy tissue yielded discordant results. The patient was diagnosed as having tuberculous lymphadenitis. She was treated with antitubercular drugs and subsequently had a reduction in cervical lymph node swelling. Polymerase chain reaction analysis is not 100% accurate; hence, its use as a diagnostic tool for mycobacterial infection requires increased attention.

Detection of aac(6')-Ib-cr in avian pathogenic Escherichia coli isolates in Japan.

We investigated the prevalence of plasmid-mediated quinolone resistance (PMQR) genes in avian pathogenic Escherichia coli (APEC) strains in Japan. A total of 117 APEC strains collected between 2004 and 2007 were examined for PMQR genes (qnrA, qnrB, qnrC, qnrD, qnrS, aac(6')-Ib-cr, qepA and oqxAB) by polymerase chain reaction. None of the APEC strains carried qnrA, qnrB, qnrC, qnrD, qnrS, qepA or oqxAB, but one of the isolates was identified as an AAC (6')-Ib-cr producer. Phylogenetic grouping, multi-locus sequence typing and serotyping showed that this isolate belonged to phylogenetic group A, sequence type 167 and untypable serogroup. To our knowledge, this is the first report of the aac (6')-Ib-cr gene in bacteria from food-producing animals in Japan.

IgG4-Related Perineural Disease.

Aims. To elucidate characteristics of IgG4-related disease involving the peripheral nervous system. Methods. Retrospective review of 106 patients with IgG4-related disease identified 21 peripheral nerve lesions in 7 patients. Clinicopathological and radiological features were examined. Results. Peripheral nerve lesions were commonly identified in orbital or paravertebral area, involving orbital (n = 9), optic (n = 4), spinal (n = 7), and great auricular nerves (n = 1). The predominant radiological feature was a distinct perineural soft tissue mass, ranging 8 to 30 mm in diameter. Histologically, the epineurium was preferentially involved by massive lymphoplasmacytic infiltration rich in IgG4(+) plasma cells. All lesions were neurologically asymptomatic and steroid-responsive at the first presentation, but one recurrent lesion around the optic nerve caused failing vision. Conclusion. IgG4-related disease of the peripheral nervous system is characterized by orbital or paravertebral localization, perineural mass formation, and rare neurologic symptoms. The term "IgG4-related perineural disease" seems appropriate to describe this entity.

Toxic multinodular goiter with low radioactive iodine uptake.

A 74-year-old woman was referred to our hospital for goiter and persistent thyrotoxicosis. She had no signs of ophthalmopathy. She was not taking thyroid hormone. Thyroid CT revealed multiple nodules. The thyroid gland was not detected on (99m)Tc scintigraphy, (123)I uptake rate was 4.5% at 24 hours without hot nodules, and aberrant goiter was negative. After partial thyroidectomy, she was treated with levothyroxine. TRAb was undetectable during the disease course, and focal destructive change or chronic lymphocytic thyroiditis on the pathological specimens was not evident. We report a rare case of toxic multinodular goiter with low radioactive iodine uptake.

Immunoglobulin G4-related periaortitis and periarteritis: CT findings in 17 patients.

PURPOSE: To retrospectively evaluate computed tomographic (CT) findings of immunoglobulin G4 (IgG4)-related disease involving the vascular system. MATERIALS AND METHODS: This study was approved by the institutional review board, and all patients included had consented to the use of their medical records for the purpose of research. The study consisted of 17 patients (16 men and one woman; age range, 54-86 years). CT findings of IgG4-related periarterial lesions were retrospectively analyzed. Radiopathologic correlations were examined on the basis of surgically resected specimens. RESULTS: A total of 22 periarterial lesions were detected in 17 patients. The lesions were located in the thoracic aorta (n = 4), abdominal aorta to iliac arteries (n = 13), superior mesenteric artery (n = 3), inferior mesenteric artery (n = 1), and splenic artery (n = 1). Radiologically, they were characterized by arterial wall thickening (mean thickness, 11 mm), relatively clear circumscription, possible association with luminal change (mostly dilated and rarely stenotic), exaggerated atherosclerotic change, and homogeneous enhancement at the late phase of contrast material-enhanced CT. Twelve patients (71%) had IgG4-related disease in other organs. Pathologically, diffuse lymphoplasmacytic infiltration, numerous IgG4-positive plasma cells, and irregular fibrosis were noted in the thickened arterial wall, especially at the adventitia. Steroid therapy administered to eight patients rapidly diminished the arterial wall thickening. One patient who did not receive steroid therapy showed spontaneous improvement at follow-up CT. CONCLUSION: IgG4-related arterial lesions occur mainly in the aorta and its main branches and are radiologically characterized by homogeneous arterial wall thickening corresponding to pathologic features of IgG4-related sclerosing inflammation in the adventitia.