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.

Anti-tumor necrosis factor-alpha treatment reduces allergic responses in an allergic rhinitis mouse model

BACKGROUND

  Tumor necrosis factor (TNF)-α is a principal mediator of the acute inflammatory response, including allergic rhinitis. TNF-α inhibitors are widely used for the treatment of inflammatory conditions such as rheumatoid arthritis and inflammatory bowel diseases; however, the effects of TNF-α inhibitors on allergic rhinitis are not well established. We aimed to investigate the effects of infliximab, a TNF-α inhibitor, on allergic rhinitis in a mouse model.

METHODS

  BALB/c mice were sensitized with ovalbumin (OVA) and alum, and challenged intranasally with OVA. The TNF-α inhibitor, infliximab was administered intraperitoneally, and multiple parameters of allergic responses were evaluated to determine the effects of infliximab.

RESULTS

  Infliximab reduced allergic symptoms and eosinophilic infiltration into the nasal mucosa. It also suppressed total and OVA-specific IgE levels, and inhibited local Th2 cytokine transcription in the nasal mucosa and systemic Th2 cytokine production by splenocytes. Furthermore, the expression of E-selectin, neither intercellular adhesion molecule 1 (ICAM-1) nor vascular cell adhesion molecule 1 (VCAM-1), in the nasal mucosa was suppressed in the infliximab-treated group when compared to the nontreated group.

CONCLUSION

  This study shows that the TNF-α inhibitor infliximab induces anti-allergic effects by decreasing local and systemic Th2 cytokine (IL-4) production, total and OVA-specific IgE levels, adhesion molecule (E-selectin) expression, and eosinophil infiltration into the nasal mucosa in an allergic rhinitis model. Therefore, infliximab should be considered as a potential agent in treating allergic rhinitis.

The importance of maximal airway response to methacholine in the prediction of asthma development in patients with allergic rhinitis

BACKGROUND

Allergic rhinitis is a known predictor and correlate of asthma incidence. However, it is not clear which patients with allergic rhinitis are at greater risk of the development of asthma.

OBJECTIVE

The aim of this study was to investigate whether airway hypersensitivity and/or increased maximal response on the dose-response curve to methacholine would predict the development of asthma in subjects with allergic rhinitis.

METHODS

One hundred and forty-one children with allergic rhinitis were prospectively studied for 7 years. At the initiation of the study, bronchial provocation test with methacholine using a stepwise increasing concentration technique was performed to measure PC(20) (provocative concentration causing a 20% fall in FEV(1)) and maximal response. Each subject was evaluated at least every 6 months and details of asthmatic symptoms or signs experienced during the intervening period were taken.

RESULTS

Twenty of 122 subjects available for the follow-up developed asthma. Nine (19.6%) of 46 hypersensitive (PC(20) < 18 mg/mL) subjects developed asthma, compared with 11 (14.5%) of 76 normosensitive subjects (P = 0.462). Eight (32%) of 25 subjects without maximal response plateau developed asthma, compared with 12 (12.4%) of 97 subjects with maximal response plateau (P = 0.018). Score test for trend revealed a significant association between the level of maximal response (P = 0.007), but not the degree of methacholine PC(20) (P = 0.123), and the future development of asthma.

CONCLUSION

An increased maximal airway response to methacholine is shown to be a better predictor for the future development of asthma in patients with allergic rhinitis, than airway hypersensitivity to methacholine.

Calmodulin-dependent activation of p38 and p42/44 mitogen-activated protein kinases contributes to c-fos expression by calcium in PC12 cells: modulation by nitric oxide

Calcium and nitric oxide (NO) are important messengers for the activity-dependent immediate-early gene (IEG) expressions in neuronal cells. In the present study, we have investigated the roles of two mitogen-activated protein (MAP) kinases, extracellular signal-regulated protein kinase (ERK) and p38 MAP kinase (p38 kinase) in calcium- and NO-induced c-fos expression in PC12 cells. Membrane depolarization-induced calcium increases activated both ERK and p38 kinase within 5 min. The activation of both ERK and p38 kinase by calcium was a calmodulin-dependent process since the pretreatment of W13 or calmidazolium, specific calmodulin antagonists, blocked calcium-induced activation of both MAP kinases. Calcium-induced c-fos expression was significantly reduced by the pretreatment of either MEK inhibitor (PD98059) or p38 kinase inhibitor (SB203580). This finding indicates that the calmodulin-dependent activation of ERK and p38 kinase is involved in calcium-induced c-fos expression. However, sodium nitroprusside and SIN-1, known to release NO, dose-dependently activated only ERK. NO-induced c-fos expression was partially inhibited by the PD98059. We also observed that NO dose-dependently potentiates not only calcium-induced c-fos expression but also calcium-induced ERK activation. In the presence of PD98059, the amplification of calcium-induced c-fos expression by NO was not observed. This result suggests that calcium- and NO-signals converge into the MEK/ERK pathway, thereby enhance IEG expressions in neuronal cells.

Light regulates Homer mRNA expression in the rat suprachiasmatic nucleus

The hypothalamic suprachiasmatic nucleus (SCN) of the mammal is the circadian pacemaker responsible for generation of circadian rhythms. Several immediate-early genes are expressed in the SCN by light stimuli which induce phase shifts of animal activity rhythms. In the present study, we investigated whether Homer, a PDZ-like protein which is rapidly induced following synaptic activation, mRNA expression is regulated by light in rat SCN. Homer mRNA expression in the SCN of rat killed at 4 h after onset of the light and dark phases was very low. One hour light stimuli during the subjective night dramatically induced Homer mRNA expression in the ventrolateral portion of the SCN, whereas light stimuli during the subjective light phase did not. This finding implies that Homer may be involved in the photic entrainment of the circadian clock.