First description of a clinical glutamine-dependent Escherichia coli with a missense mutation in the glnA.

INTRODUCTION: Small-colony variants (SCVs) of bacteria are subpopulations with a small colony size, low growth rate, and atypical colony morphology. The purpose of this study was to comprehensively elucidate the characteristics and underlying mechanism of the development of a glutamine-dependent SCV of E. coli, GU-92SCV, isolated from the blood of a patient with pyelonephritis. METHODS: The GU-92SCV strain was tested for auxotrophy testing for glutamine. DNA mutations in genes related to glutamine synthesis were analysed by sequencing. The isolate's proliferation and antimicrobial susceptibility in Mueller-Hinton II medium supplemented with glutamine were examined. RESULTS: The colony of the GU-92SCV strain did not grow on Mueller-Hinton II agar, but growth around the filter paper containing l-glutamine was enhanced on Mueller-Hinton II agar. The GU-92SCV strain had a single nucleotide substitution in glnA, c.193G>A, corresponding to p.Asp65Asn. Changing c.193G>A to the wild-type sequence in glnA restored these phenotypes. Because GU-92SCV did not grow in Mueller-Hinton II broth, antimicrobial susceptibility test results were not obtained; however, in the presence of 10 mg mL-1l-glutamine, the results were consistent with those of the revertant strain GU-92REV. CONCLUSION: To the best of our knowledge, this is the first clinical isolation of a glutamine-dependent E. coli SCV from a patient blood culture. Our data showed that glnA was important for the growth of E. coli in Mueller-Hinton II medium, which also required the presence of glutamine when performing antimicrobial susceptibility testing for glutamine-dependent SCV strains.

Vaccination Status and Antibody Titers against Rubella and Measles among Japanese Female College Students Majoring in Childcare between 2015 and 2018.

In 2014, for the protection of medical workers against measles and rubella infection, the Japanese Society for Infection Prevention and Control (JSIPC) recommended either maintaining antibody titers of seroprotective range or two-dose vaccination. JSIPC defined antibody titers into 3 ranges: seroprotective as expected prevention of infection, seronegative as under detection levels, and seropositive as antibody titers ranged between seronegative and seroprotective. This study aimed to explore the association between the number of vaccine doses received and the antibody titers against measles and rubella among Japanese college students majoring in childcare. A total of 841 female students with no history of measles or rubella were serologically screened at the time of college admission between 2015 and 2018. All 841 students had been vaccinated against measles; 738 (87.8%) received two doses of the measles vaccine and 103 (12.2%) received one dose. Likewise, 839 students, except for two, had been vaccinated against rubella; 719 (85.7%) received two doses of the rubella vaccine and 120 (14.3%) received one dose. We thus found that 107 students (12.7%) were seropositive for measles-specific IgG and 731 (86.9%) attained seroprotective titers. By contrast, in case of rubella-specific IgG, only 462 students (55.1%) attained seroprotective titers, and 371 students (44.1%) were seropositive. The two students without receiving rubella vaccination were classified as seronegative. In conclusion, despite that > 85% of students surveyed had received two doses of measles and rubella vaccines, a substantial number of students remain susceptible to measles and especially rubella at the time of college admission.

High Frequency of Hepatitis B Core and Surface Antibodies in Hepatitis C Virus-Infected Patients on the Screening Examination.

BACKGROUND: Hepatitis B virus (HBV) and hepatitis C virus (HCV) are important human pathogens that cause chronic liver disease and hepatocellular carcinoma. Co-infection of HBV and HCV is not uncommon, particularly in countries where these two viruses are endemic. Therefore, the characteristics of HBV co-infection in HCV antibody (HCVAb) -positive Japanese patients found on the screening examination were analyzed. PATIENTS AND METHODS: Between January and December 2011, HCVAb status was evaluated as the screening examination in 12,582 patients in Gunma University Hospital, and it was positive in 402 patients (3.2%). In 331 HCVAb-positive/HBs antigen (HBsAg) -negative patients with available residual serum, HBs antibody (HBsAb) and HBc antibody (HBcAb) were examined. In addition, HCV-RNA was examined in 291 patients with available residual serum. HBV-DNA and HBV core-related antigen (HBcrAg) were examined in 106 patients with available residual serum. RESULTS: The HCVAb titer was distributed between 1 and 18 sample/cutoff index (S/CO). 275 patients (83.1%) had a high HCVAb titer (S/CO ≥10). HCV-RNA was positive in 230 (79.0%) patients, and it was more frequently detected in HCVAb high-titer patients (88%) than in low-titer patients (32%; p < 0.0001); 61 (18.4%) and 101(30.5%) patients were positive for HBsAb and HBcAb, respectively. Of 230 HCV-RNA-positive patients, 38 (16.5%) and 59 (25.6%) were positive for HBsAb and HBcAb, respectively. Three (2.8%) and 2 (1.9%) of 106 patients had HBV-DNA and HBVCrAg. The ALT level was higher than 30 IU/L in 146/327 (44.6%) HCVAb-positive patients who had ALT levels measured. Abnormal ALT elevation was more frequent in HCVAb high-titer patients than in low-titer patients (48.3% vs. 26.8%; p = 0.0031), and in HCV-RNA-positive patients than in HCV-RNA-negative patients (54.2% vs. 13.3%; p < 0.001). CONCLUSION: HBV reactivation should be noted in these HCVAb-positive/HBsAg-negative patients on the screening examination if these patients must receive chemotherapy or immunosuppressive therapy. In addition, surveying of HBsAb in addition to HBcAb is also necessary.

Suppressive Regulation by MFG-E8 of Latent Transforming Growth Factor ß-Induced Fibrosis via Binding to αv Integrin: Significance in the Pathogenesis of Fibrosis in Systemic Sclerosis.

OBJECTIVE: Several studies have demonstrated that the secreted glycoprotein and integrin ligand milk fat globule-associated protein with epidermal growth factor- and factor VIII-like domains (MFG-E8) negatively regulates fibrosis in the liver, lungs, and respiratory tract. However, the mechanisms and roles of MFG-E8 in skin fibrosis in systemic sclerosis (SSc) have not been characterized. We undertook this study to elucidate the role of MFG-E8 in skin fibrosis in SSc. METHODS: We assessed expression of MFG-E8 in the skin and serum in SSc patients. We examined the effect of recombinant MFG-E8 (rMFG-E8) on latent transforming growth factor ß (TGFß)-induced gene/protein expression in SSc fibroblasts. We examined the effects of deficiency or administration of MFG-E8 on fibrosis mouse models. RESULTS: We demonstrated that MFG-E8 expression around dermal blood vessels and the serum MFG-E8 level in SSc patients (n = 7 and n = 44, respectively) were lower than those in healthy individuals (n = 6 and n = 28, respectively). Treatment with rMFG-E8 significantly inhibited latent TGFß-induced expression of type I collagen, α-smooth muscle actin, and CCN2 in SSc fibroblasts (n = 3-8), which suggested that MFG-E8 inhibited activation of latent TGFß as well as TGFß signaling via binding to αv integrin. In a mouse model of bleomycin-induced fibrosis (n = 5-8) and in a TSK mouse model (a genetic model of SSc) (n = 5-10), deficient expression of MFG-E8 significantly enhanced both pulmonary and skin fibrosis, and administration of rMFG-E8 significantly inhibited bleomycin-induced dermal fibrosis. CONCLUSION: These results suggest that vasculopathy-induced dysfunction of pericytes and endothelial cells, the main cells secreting MFG-E8, may be associated with the decreased expression of MFG-E8 in SSc and that the deficient inhibitory regulation of latent TGFß-induced skin fibrosis by MFG-E8 may be involved in the pathogenesis of SSc and may be a therapeutic target for fibrosis in SSc patients.

Seroprevalence of measles- and mumps-specific immunoglobulin G among Japanese healthcare students increased during 2007-2012.

We evaluated the seroprevalence of vaccine-preventable infectious diseases among Japanese healthcare students to create immunization guidelines. Between 2007 and 2012, a total of 1746 Japanese medical, nursing, and paramedical students were serologically screened for measles, mumps, rubella, varicella, and hepatitis B virus (HBV) antibodies at the time of admission. In 2007, the seroprevalence of measles and mumps was 52.7% and 65.6%, respectively. The seroprevalence of measles dramatically increased to 96.6% in 2009 and was then sustained at >90%. The seroprevalence of mumps gradually increased to >80.0% between 2010 and 2012. The seroprevalence of rubella remained at >90% except in 2008 (85.6%), and the seroprevalence of varicella was sustained at >92% throughout 2007-2012. The seroprevalence of HBV antibody remained at <7% during 2007-2012. Although the seroprevalence of vaccine-preventable infectious diseases among Japanese healthcare students increased during the 2007-2012 study period, a substantial number of students were susceptible to vaccine-preventable infectious diseases. Therefore, we propose targeted immunization of Japanese healthcare students using serological screening prior to clinical training.