Optimal therapeutic recommendation for Clostridioides difficile infection in pediatric and adolescent populations: a systematic review and meta-analysis

We conducted a systematic review and meta-analysis to examine the efficacy profiles of metronidazole (MNZ) and vancomycin (VCM) in pediatric and adolescent patients with Clostridioides difficile infection (CDI). A systematic review and meta-analysis was conducted using four electronic databases (PubMed, Cochrane Library, Web of Science, and Clinicaltrials.gov) through July 6, 2022. We analyzed the clinical cure and recurrence rates to determine the efficacy of MNZ and VCM. The clinical cure rates in all included studies were not significantly different between MNZ and VCM (OR = 0.63; 95% CI = 0.36-1.10; I² = 0%; P = 0.10). Subgroup analyses were performed separately for each region to account for regional differences in the CDI. MNZ treatment achieved significantly lower clinical cure rates than did VCM in the United States of America (USA) and Europe (OR = 0.42, 95% CI = 0.19-0.93, I² = 0%, P = 0.03). Recurrence rates were not significantly different between MNZ and VCM (OR = 1.48, 95% CI = 0.62-3.53, I² = 28%, P = 0.38).    Conclusion: MNZ exhibited significantly lower clinical cure rates than did VCM in the US and Europe; therefore, it is not recommended for the management of CDI in pediatric and adolescent populations. What is Known: • The unavailability of robust data on recommendations of therapeutic agents for the management of Clostridioides difficile infections in children precludes effective antibiotic choice. What is New: • Metronidazole exhibited significantly lower clinical cure rates than did vancomycin in the United States of America and Europe and recurrence rate was not significantly different between metronidazole and vancomycin; therefore, it is not recommended for the management of Clostridioides difficile infection in children.

Hyper-expression of Osteocalcin mRNA in Odontoblasts of Hyp Mice

The Hyp mouse is a murine homologue of human X-linked hypophosphatemia that displays hypo-mineralization in bone and dentin. In this study, we tested the hypothesis that the defect in Hyp mice leads to alterations in the expression of dentin matrix proteins that may be associated with the hypo-mineralization changes in the tissues. Quantitative RT-PCR analyses showed that expression of the osteocalcin gene in Hyp mice tooth germ samples was significantly higher than in wild-type mice, whereas the gene expressions of osteonectin, osteopontn, dentin matrix protein 1, and type I collagen in both types of mice were similar. Further, cultured Hyp mice tooth germ samples exhibited a higher expression of the osteocalcin gene than did those from wild-type mice, which was in accord with the results of our in vivo analysis. These findings suggest that osteocalcin mRNA is highly expressed in Hyp mice odontoblasts and may be associated with dentin hypo-mineralization.

Gene therapy improves dental manifestations in hypophosphatasia model mice

BACKGROUND AND OBJECTIVE

Hypophosphatasia is a rare inherited skeletal disorder characterized by defective bone mineralization and deficiency of tissue non-specific alkaline phosphatase (TNSALP) activity. The disease is caused by mutations in the liver/bone/kidney alkaline phosphatase gene (ALPL) encoding TNSALP. Early exfoliation of primary teeth owing to disturbed cementum formation, periodontal ligament weakness and alveolar bone resorption are major complications encountered in oral findings, and discovery of early loss of primary teeth in a dental examination often leads to early diagnosis of hypophosphatasia. Although there are no known fundamental treatments or effective dental approaches to prevent early exfoliation of primary teeth in affected patients, several possible treatments have recently been described, including gene therapy. Gene therapy has also been applied to TNSALP knockout mice (Alpl^-/- ), which phenocopy the infantile form of hypophosphatasia, and improved their systemic condition. In the present study, we investigated whether gene therapy improved the dental condition of Alpl^-/- mice.

MATERIAL AND METHODS

Following sublethal irradiation (4 Gy) at the age of 2 d, Alpl^-/- mice underwent gene therapy using bone marrow cells transduced with a lentiviral vector expressing a bone-targeted form of TNSALP injected into the jugular vein (n = 3). Wild-type (Alpl^+/+ ), heterozygous mice (Alpl^+/- ) and Alpl^-/- mice were analyzed at 9 d of age (n = 3 of each), while Alpl^+/+ mice and treated or untreated Alpl^-/- mice were analyzed at 1 mo of age (n = 3 of each), and Alpl^+/- mice and Alpl^-/- mice with gene therapy were analyzed at 3 mo of age (n = 3 of each). A single mandibular hemi-section obtained at 1 mo of age was analyzed using a small animal computed tomography machine to assess alveolar bone formation. Other mandibular hemi-sections obtained at 9 d, 1 mo and 3 mo of age were subjected to hematoxylin and eosin staining and immunohistochemical analysis of osteopontin, a marker of cementum.

RESULTS

Immunohistochemical analysis of osteopontin, a marker of acellular cementum, revealed that Alpl^-/- mice displayed impaired formation of cementum and alveolar bone, similar to the human dental phenotype. Cementum formation was clearly present in Alpl^-/- mice that underwent gene therapy, but did not recover to the same level as that in wild-type (Alpl^+/+ ) mice. Micro-computed tomography examination showed that gene therapy improved alveolar bone mineral density in Alpl^-/- mice to a similar level to that in Alpl^+/+ mice.

CONCLUSIONS

Our results suggest that gene therapy can improve the general condition of Alpl^-/- mice, and induce significant alveolar bone formation and moderate improvement of cementum formation, which may contribute to inhibition of early spontaneous tooth exfoliation.

A specific Streptococcus mutans strain aggravates non-alcoholic fatty liver disease

OBJECTIVE

Streptococcus mutans, a major dental caries pathogen, has shown to be associated with the aggravation of cerebral hemorrhage and inflammatory bowel diseases. In this study, we evaluated the effects ofS. mutans on the development of non-alcoholic steatohepatitis (NASH) in a mouse model.

MATERIALS AND METHODS

Streptococcus mutans oral strain MT8148 (serotype c) and a blood isolate TW871 (k) were used. C57BL/6J mice (6 weeks old)were fed a high-fat diet for 4 weeks; the test strains or phosphate-buffered saline was then intravenously administered. Mice were euthanized after 8 or 12 weeks. Whole body, extirpated liver, and visceral fat weights were determined, and histopathological evaluations of the liver specimens were performed.

RESULTS

Mice infected with TW871 showed significantly greater body and liver weights than those administered MT8148 or phosphate-buffered saline. Histopathological analyses revealed prominent infiltration of inflammatory cells and adipocellular deposition in livers extirpated 8 weeks after an infection with TW871; fibrosis was also observed in livers extirpated after 12 weeks.

CONCLUSION

These results suggest that a specific strain of S. mutans could induce NASH.

Aggravation of inflammatory bowel diseases by oral streptococci

OBJECTIVES

Streptococcus mutans can aggravate colitis in mice. We evaluated the virulence of colitis using type strains as well as blood isolates of several oral streptococcal species.

MATERIALS AND METHODS

We investigated the susceptibility of blood isolates of several oral streptococci to phagocytosis, adhesion to and invasion of hepatic cells and interferon-γ secretion. A mouse model of dextran sodium sulphate-induced colitis was used to evaluate bacterial aggravation of colitis. In addition, interferon-γ antibody was administered to mice with prominent aggravation of colitis.

RESULTS

In vitro analyses showed that Streptococcus sanguinis ATCC 10556 was a possible virulent strain among type strains of several oral streptococci, and that analysis of blood isolates of S. sanguinis TW289 revealed a potential virulent strain. Intravenous administration of ATCC 10556 and TW289 caused prominent aggravation of dextran sodium sulphate-induced colitis, and histopathological examinations showed that interferon-γ secretion due to infection of hepatic cells caused colitis aggravation. Administration of interferon-γ antibody suppressed TW289-induced colitis.

CONCLUSION

These results suggest that some virulent oral streptococcal strains are associated with the aggravation of colitis induced by enhanced secretion of interferon-γ when they invade the bloodstream.

Phex mutation causes the reduction of npt2b mRNA in teeth

Hyp mice (murine homologue of human X-linked hypophosphatemia) have a disorder in phosphate homeostasis, and display hypomineralization in bones and teeth. We investigated whether a mutation of Phex (phosphate regulating gene homologies to endopeptidase on the X chromosome) has an effect on the expression level of type II sodium-dependent phosphate co-transporter (Npt2) in the developing teeth of the Hyp mouse. Quantitative RT-PCR analyses revealed that the amount of Npt2b mRNA, an isoform of Npt2, in Hyp mouse tooth germs was significantly lower than that in wild-type mice, in both in vivo and in vitro experiments. In addition, tooth germs from wild-type mice cultured in medium supplemented with antisense oligo-deoxynucleotide for Phex also showed a reduction of Npt2b mRNA expression. These findings suggest that the loss of Phex function is related to the defect of Npt2b expression in teeth, and Npt2b reduction is an intrinsic defect of Hyp murine teeth.

Dentinal defects in Hyp mice not caused by hypophosphatemia alone

The Hyp mouse is a murine homolog of human X-linked hypophosphatemic rickets and displays hypo-mineralization in bone and dentin due to a defect of the phosphate-regulating gene with homology to endopeptidase on the X chromosome (Phex) gene. It has long been considered that the bone and dentin defects in Hyp mice are caused by hypophosphatemia alone, however, several recent studies have indicated the possibility that intrinsic defects are present in Hyp mice osteoblasts. Further, we previously found a hyper-expression of osteocalcin (OC) mRNA in Hyp mouse odontoblasts and suggested the possibility of the presence of intrinsic defects. In the present study, we evaluated morphological features and OC mRNA expression levels in tooth germs of Nor mice with a normal phex gene and a low concentration of serum phosphate, and compared them to those in Hyp and wild-type mice. Nor mice exhibited low serum phosphate levels, however, did not show the characteristic features of dentin defects seen in Hyp mice, such as widened predentin and hyper-expression of OC mRNA. These results suggest that the hypo-mineralization of dentin in Hyp mice is not dependent on serum phosphate level, but rather is affected by intrinsic defects in odontoblasts.