Regional and annual patterns in respiratory virus co-infection etiologies and antibiotic prescriptions for pediatric mycoplasma pneumoniae pneumonia

OBJECTIVE

Mycoplasma pneumoniae (M. pneumoniae) pneumonia is the second-most common cause of community-acquired pneumonia (CAP). This study aimed at investigating into the prevalence of macrolide-resistant M. pneumoniae (MRMP) with respiratory virus co-infection and the antibiotic prescriptions in children with CAP in four provinces in Korea, and to assess the variations in the findings across regions and throughout the year.

PATIENTS AND METHODS

This prospective study was conducted in 29 hospitals in Korea between July 2018 and June 2020. Among the enrolled 1,063 children with CAP, all 451 patients with M. pneumoniae underwent PCR assays of M. pneumoniae and respiratory viruses, and the presence of point mutations of residues 2063 and 2064 was evaluated.

RESULTS

Gwangju-Honam (88.6%) showed the highest prevalence of MRMP pneumonia, while Daejeon-Chungcheong (71.3%) showed the lowest, although the differences in prevalence were not significant (p=0.074). Co-infection of M. pneumoniae pneumonia and respiratory virus was observed in 206 patients (45.4%), and rhinovirus co-infection (101 children; 22.2%) was the most frequent. The prevalence of MRMP pneumonia with respiratory virus co-infection and the antibiotic prescriptions differed significantly among the four provinces (p < 0.05). The monthly rate of MRMP pneumonia cases among all cases of M. pneumoniae pneumonia and tetracycline or quinolone prescriptions did not differ significantly among the four regions (trend p > 0.05) during the study period.

CONCLUSIONS

The prevalence of M. pneumoniae pneumonia with virus co-infection and antibiotic prescriptions could differ according to region, although the MRMP pneumonia rate showed no difference within Korea.

Immunocytochemical evidence that amyloid beta (1-42) impairs endogenous antioxidant systems in vivo

Amyloid beta, the major constituent of the senile plaques in the brains of patients with Alzheimer's disease, is cytotoxic to neurons and has a central role in the pathogenesis of the disease. We have previously demonstrated that potent antioxidants idebenone and alpha-tocopherol prevent learning and memory impairment in rats which received a continuous intracerebroventricular infusion of amyloid beta, suggesting a role for oxidative stress in amyloid beta-induced learning and memory impairment. To test the hypothesis, in the present study, we investigated alterations in the immunoreactivity of endogenous antioxidant systems such as mitochondrial Mn-superoxide dismutase, glutathione, glutathione peroxidase and glutathione-S-transferase following the continuous intracerebroventricular infusion of amyloid beta for 2 weeks. The infusion of amyloid beta (1-42) resulted in a significant reduction of the immunoreactivity of these antioxidant substances in such brain areas as the hippocampus, parietal cortex, piriform cortex, substantia nigra and thalamus although the same treatment with amyloid beta (40-1) had little effect. The alterations induced by amyloid beta (1-42) were not uniform, but rather specific for each immunoreactive substance in a brain region-dependent manner. These results demonstrate a cytological effect of oxidative stress induced by amyloid beta (1-42) infusion. Furthermore, our findings may indicate a heterogeneous susceptibility to the oxidative stress produced by amyloid beta.

Protection of methamphetamine nigrostriatal toxicity by dietary selenium

Multiple dose administration of methamphetamine (MA) results in long-lasting toxic effects in the nigrostriatal dopaminergic system. These effects are considered to be primarily due to oxidative damage mediated by increased production of hydrogen peroxide or other reactive oxygen species in the dopaminergic system. The present study was designed to determine the protective effects of dietary antioxidant selenium on MA-induced neurotoxicity in the nigrostriatal dopaminergic system. Male C57BL/6J mice were fed either selenium-deficient (< 0.01 ppm Se) or selenium-replete (0.2 ppm Se) diets for 90 days. MA treatment decreased the dopamine (DA) levels in the striatum and substantia nigra (SN) of both Se-replete and Se-deficient animals. However, in Se-replete animals, this DA depletion was significantly attenuated in both the striatum and SN. A novel observation is that MA administration resulted in increased activity of Cu,Zn-SOD in the brains of both Se-deficient and Se-replete animals. However, MA administration to Se-deficient animals exhibited a higher Cu,Zn-SOD activity in the nigrostriatal system than the control animals. Elevated malondialdehyde (MDA) levels in the striatum and SN were also observed in Se-deficient MA-treated animals. Se repletion significantly increased the glutathione peroxidase (GPx) activity and the ratio of reduced glutathione (GSH)/oxidized glutathione (GSSG) in the MA-treated animals. In conclusion, we have shown that dietary Se attenuated methamphetamine neurotoxicity and that this protection involves GPx-mediated antioxidant mechanisms. Even though Cu,Zn-SOD activity was significantly elevated by MA treatment, the role of this enzyme in MA-mediated neurotoxicity is not yet clear.

A low dose of streptozotocin prevents kainic acid-induced seizures and lethal effects in the rat

1. The effect of streptozotocin (STZ), a nitric oxide (NO) donor, on kainic acid (KA)-induced neurotoxicity was examined in Sprague-Dawley rats. 2. The administration of KA (8 mg/kg, i.p.) produced significant neurotoxicity accompanied with increased immunoreactivity for Fos-related antigen in the rat hippocampus. 3. Pretreatment with STZ (15 mg/kg, i.m.) significantly blocked the neurotoxicity induced by KA. 4. Thus, the neuroprotective effect of STZ may, at least in part, reflect the role of NO in inhibiting seizures.