Search

Helicobacter sp. MIT 01-6451 has been detected in SPF mice kept in Japan. To characterize strain MIT 01-6451, its infection route during fetal and neonatal life and effects on pregnancy were investigated using immunocompetent and immunodeficient mouse strains (BALB/c, C57BL/6, and SCID). MIT 01-6451 was detected in the uterus, vagina, and mammary glands of 50% of infected SCID mice, whereas these tissues were all negative in immunocompetent mice. No fetal infections with MIT 01-6451 were detected at 16?18 days after pregnancy in any mouse strain. In newborn mice, MIT 01-6451 was detected in intestinal tissue of C57BL/6 and SCID mice at 9?11 days after birth, but not in BALB/c mice. The IgA and IgG titers to MIT 01-6451 in sera of C57BL/6 female mice were significantly lower than those of BALB/c mice. Although no significant differences in the number of newborns per litter were observed between MIT 01-6451-infected and MIT 01-6451-free dams, the birth rate was lower in infected SCID mice than in control SCID mice. The present results indicated that MIT 01-6451 infects newborn mice after birth rather than by vertical transmission to the fetus via the placenta and that MIT 01-6451 infection shows opportunistically negative effects on the birth rate. In addition, the maternal immune response may affect infection of newborn mice with MIT 01-6451 through breast milk., Experimental Animals, 64(4), pp.375-382; 2015

To determine the prevalence of drug resistant bacteria colonizing laboratory mice, we isolated and characterized vancomycin-resistant Enterococcus species (VRE) from commercially available mice. A total of 24 VRE isolates were obtained from 19 of 21 mouse strains supplied by 4 commercial breeding companies. Of these, 19 isolates of E. gallinarum and 5 isolates of E. casseliflavus possessing the vanC1 and vanC2/3 genes intrinsically, exhibited intermediate resistance to vancomycin respectively. In addition, these isolates also exhibited diverse resistant patterns to erythromycin, tetracycline, and ciprofloxacin, whereas the use of antibiotics had not been undertaken in mouse strains tested in this study. Although 6 virulence-associated genes (ace, asa, cylA, efaA, esp, and gelE) and secretion of gelatinase and hemolysin were not detected in all isolates, 23 of 24 isolates including the isolates of E. casselifalvus secreted ATP into culture supernatants. Since secretion of ATP by bacteria resident in the intestinal tract modulates the local immune responses, the prevalence of ATP-secreting VRE in mice therefore needs to be considered in animal experiments that alter the gut microflora by use of antibiotics., Experimental Animals, 63(3), pp.297-304; 2014

To determine the prevalence of drug resistant bacteria colonizing laboratory mice, we isolated and characterized vancomycin-resistant Enterococcus species (VRE) from commercially available mice. A total of 24 VRE isolates were obtained from 19 of 21 mouse strains supplied by 4 commercial breeding companies. Of these, 19 isolates of E. gallinarum and 5 isolates of E. casseliflavus possessing the vanC1 and vanC2/3 genes intrinsically, exhibited intermediate resistance to vancomycin respectively. In addition, these isolates also exhibited diverse resistant patterns to erythromycin, tetracycline, and ciprofloxacin, whereas the use of antibiotics had not been undertaken in mouse strains tested in this study. Although 6 virulence-associated genes (ace, asa, cylA, efaA, esp, and gelE) and secretion of gelatinase and hemolysin were not detected in all isolates, 23 of 24 isolates including the isolates of E. casselifalvus secreted ATP into culture supernatants. Since secretion of ATP by bacteria resident in the intestinal tract modulates the local immune responses, the prevalence of ATP-secreting VRE in mice therefore needs to be considered in animal experiments that alter the gut microflora by use of antibiotics.

An unidentified Helicobacter species, strain MIT 01-6451, was frequently detected in mice obtained from domestic commercial and academic institutions in Japan. To partially characterize this strain, its distributions in the gastrointestinal tract and hepatobiliary system of mice were investigated. In gastrointestinal tissues, this strain was detected in all cecum, colon, and feces samples tested, whereas fewer mice were positive in the ileum, jejunum, and duodenum. Interestingly, strain MIT 01-6451 was also detected in most stomach samples and in 33% of gallbladder samples. One mouse was found to be infected with multiple Helicobacter species. Fourteen copies of 16S rRNA genes were cloned from the tissues of this mouse. One had the highest level of sequence homology with H. canadensis, while 13 had the highest level of homology with the H. ganmani type strain or strain MIT 01-6451. Twelve of these 13 16S rRNA genes were mosaic sequences, being partially derived from H. ganmani and strain MIT 01-6451. These results suggest that H. ganmani and Helicobacter sp. MIT 01-6451 are prevalent in specific-pathogen-free mouse colonies in Japan and that lateral gene transfer probably occurs among Helicobacter species during coinfection.

Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine essential for delayed hypersensitivity in vivo, and is involved in bronchiolitis obliterans and late rejection in lung transplantation. We tested here whether neutralization of MIF using anti-MIF antibody prevents such a response. We examined the MIF mRNA expression level and changes in allograft tracheal epithelium and intraluminal obstruction in a rat allograft model. Lewis rat (RT1l) underwent heterotopic tracheal transplantation from Brown Norway rats (RT1n) in the omentum. Anti-MIF antibody was injected in the peritoneum. Rats were divided into three groups (non-treated allograft, allograft treated with normal rabbit IgG and allograft treated with anti-MIF antibody). Implants were harvested on days 7 or 21 for histological analysis. MIF mRNA expression was higher in the allograft at days 7 and 21 than in the isograft. The epithelium in non-treated allograft was almost absent at day 7. The epithelial height in the anti-MIF-treated graft was higher than that in normal IgG-treated grafts. The intraluminal space was mostly replaced by granulation tissue at day 21 in the untreated group. The proportion of obliterans was lowest in the anti-MIF group, the second lowest in the untreated group and the third lowest in the normal IgG-treated grafts, and the difference was significant (p, Acta medica Nagasakiensia. 2006, 51(2), p.51-56

Guinea pig (GP) sera seropositive to human parainfluenza virus type 3 (PIV-3) antigen were found previously in our laboratory. In the present study, we attempted to isolate and characterize a new agent from GP colonies. The new agent was isolated from lung homogenate of sentinel GPs, which were maintained in the GP room containing the serologically positive GP breeding colony. This new agent was found to be comparable to human and bovine PIV-3 strains in regard to its moderate cytopathic effects, hemagglutinating activity, and neutralizing activity, and moreover, it was found to produce antigens cross-reactive to both of the latter PIV-3s. The resemblance between the new isolates and the other PIV-3s was supported by the SDS-PAGE and Western blot analysis of the viral proteins. This is the first report of the isolation of a type 3-like parainfluenza virus from GP. This finding is significant, insofar as an inapparent infection with the virus may concern animal experimentation in the use of GP., Acta medica Nagasakiensia. 2001, 46(3-4), p.15-18

The sequence of the unique short (U(S)) region of monkey B virus (BV) was determined. The 13 genes identified are arranged in the same order and orientation as in herpes simplex virus (HSV). These results demonstrate that the BV U(S) region is entirely colinear with that of HSV type 1 (HSV-1), HSV-2, and simian agent 8 virus.

International audience; Persistent LCMV infection in wild-derived MAI/Pas mice housed under conventional conditions remained undetected for a decade, despite periodic health monitoring using dirty-bedding sentinels. When MAI/Pas mice were rederived by embryo transfer, recipient mothers produced antiLCMV antibodies, which first revealed the presence of the virus in the colony. Before this information was obtained, MAI/Pas mice had been shipped to another facility, undergone cesarean rederivation there, and been introduced into the recipient barrier. The foster mothers of rederived pups were LCMV-negative according to enzyme-linked immunosorbent assay, but sera of both cesarean-rederived MAI/Pas mice and their foster mothers were positive for LCMV infection by immunofluorescent assay (IFA). LCMV was isolated from the MAI/Pas mice, and its genomic RNA was sequenced. Examination of animal technicians in contact with LCMV-infected mice and of other mouse samples by IFA or a reverse transcriptase-polymerase chain reaction test (or both) revealed that neither the workers nor other animals had been infected with LCMV. Experimental data showed that LCMV transmission from persistently infected mice to naïve ones occurred only after direct contact of animals housed in the same cage. This experience demonstrates the importance of careful viral monitoring in the transfer of laboratory rodents between institutions, the limitation of dirty-bedding sentinels for detection of LCMV infection, and the inadequacy of cesarean rederivation for elimination of enzootic LCMV infection.