Low level ß-lactamase production in methicillin-resistant staphylococcus aureus strains with ß-lactam antibiotics-induced vancomycin resistance

BACKGROUND: A class of methicillin-resistant Staphylococcus aureus (MRSA) shows resistance to vancomycin only in the presence of ß-lactam antibiotics (BIVR). This type of vancomycin resistance is mainly attributable to the rapid depletion of free vancomycin in the presence of ß-lactam antibiotics. This means that ß-lactam antibiotics remain active or intact in BIVR culture, although most MRSA cells are assumed to produce ß-lactamase. We hypothesised that the BIVR cells either did not harbour the ß-lactamase gene, blaZ, or the gene was quiescent. We tested this hypothesis by determining ß-lactamase activity and conducting PCR amplification of blaZ. RESULTS: Five randomly selected laboratory stock BIVR strains showed an undetectable level of ß-lactamase activity and were blaZ-negative. Five non-BIVR stock strains showed an average ß-lactamase activity of 2.59 ± 0.35 U. To test freshly isolated MRSA, 353 clinical isolates were collected from 11 regionally distant hospitals. Among 25 BIVR strains, only 16% and 8% were blaZ positive and ß-lactamase-positive, respectively. In contrast, 95% and 61% of 328 non-BIVR strains had the blaZ gene and produced active ß-lactamase, respectively. To know the mechanism of low ß-lactamase activity in the BIVR cells, they were transformed with the plasmid carrying the blaZ gene. The transformants still showed a low level of ß-lactamase activity that was several orders of magnitude lower than that of blaZ-positive non-BIVR cells. Presence of the ß-lactamase gene in the transformants was tested by PCR amplification of blaZ using 11 pairs of primers covering the entire blaZ sequence. Yield of the PCR products was consistently low compared with that using blaZ-positive non-BIVR cells. Nucleotide sequencing of blaZ in one of the BIVR transformants revealed 10 amino acid substitutions. Thus, it is likely that the ß-lactamase gene was modified in the BIVR cells to downregulate active ß-lactamase production. CONCLUSIONS: We concluded that BIVR cells gain vancomycin resistance by the elimination or inactivation of ß-lactamase production, thereby preserving ß-lactam antibiotics in milieu, stimulating peptidoglycan metabolism, and depleting free vancomycin to a level below the minimum inhibitory concentration of vancomycin

Pallidal Hyperdopaminergic Innervation Underlying D2 Receptor-Dependent Behavioral Deficits in the Schizophrenia Animal Model Established by EGF

Epidermal growth factor (EGF) is one of the ErbB receptor ligands implicated in schizophrenia neuropathology as well as in dopaminergic development. Based on the immune inflammatory hypothesis for schizophrenia, neonatal rats are exposed to this cytokine and later develop neurobehavioral abnormality such as prepulse inhibition (PPI) deficit. Here we found that the EGF-treated rats exhibited persistent increases in tyrosine hydroxylase levels and dopamine content in the globus pallidus. Furthermore, pallidal dopamine release was elevated in EGF-treated rats, but normalized by subchronic treatment with risperidone concomitant with amelioration of their PPI deficits. To evaluate pathophysiologic roles of the dopamine abnormality, we administered reserpine bilaterally to the globus pallidus to reduce the local dopamine pool. Reserpine infusion ameliorated PPI deficits of EGF-treated rats without apparent aversive effects on locomotor activity in these rats. We also administered dopamine D1-like and D2-like receptor antagonists (SCH23390 and raclopride) and a D2-like receptor agonist (quinpirole) to the globus pallidus and measured PPI and bar-hang latencies. Raclopride (0.5 and 2.0 µg/site) significantly elevated PPI levels of EGF-treated rats, but SCH23390 (0.5 and 2.0 µg/site) had no effect. The higher dose of raclopride induced catalepsy-like changes in control animals but not in EGF-treated rats. Conversely, local quinpirole administration to EGF-untreated control rats induced PPI deficits and anti-cataleptic behaviors, confirming the pathophysiologic role of the pallidal hyperdopaminergic state. These findings suggest that the pallidal dopaminergic innervation is vulnerable to circulating EGF at perinatal and/or neonatal stages and has strong impact on the D2-like receptor-dependent behavioral deficits relevant to schizophrenia

20１１ネン カラ ２０１３ネン ノ ヤマガタケン ニ オケル ミッツ ノ コトナル イデンシガタ ノ ハイエン マイコプラズマ ノ チイキテキ ヒロガリ ト マクロライド タイセイ カブ シュツゲン ノ タイミング ニ カンスル ケントウ

Background: We previously revealed that several multiple-locus variable-number tandem-repeat analyses（MLVA）and P1 types of Mycoplasma pneumoniae（M. pneumoniae）cocirculated between 2011 and 2013 in Yamagata, Japan. However, the regional spread of M. pneumoniae infection by genotype is not reported yet. It remains unclear whether there is a difference in the spread of macrolide-resistant M. pneumoniae among genotypes. Methods: Genotypes were labeled according to 4-locus（Mpn 13, 14, 15, and 16）MLVA and P1 types. A total of 208 strains belonging to three major genotypes, i.e., type 4-5-7-2, 1; 4-5-7-3, 1; and 3-5-6-2, 2c, were analyzed by combining with the information of macrolide resistance-associated mutation and the patients’ information including residence. Results and Discussion: The three genotypes were widely distributed over more than four cities and towns in Yamagata Prefecture, cocirculating between late 2011 and early 2013, and there was little difference in the duration of their epidemics. Timing of macrolide-resistant strain appearance during the epidemic period differed between type 4-5-7-2, 1 and type 4-5-7-3, 1, and it did not appear throughout type 3-5-6-2, 2c epidemic. These genotypic differences can account for the variation in the prevalence of macrolide resistance-associated mutations in each of the studied areas

Associations between Optimism and Attentional Biases as Measured by Threat-Avoidance and Positive-Search Tasks

Evidence suggests that optimism has a positive impact on health status. Attentional bias modification (ABM) may be beneficial for enhancing optimism, but its effective application requires a detailed investigation of the association between attentional bias and optimism. This study aimed to determine the association between attentional bias and optimism based on different task types. Eighty-four participants completed the attentional bias measures using the dot-probe task (DPT), emotional visual search task (EVST) paradigms, and psychological assessments. Optimism was assessed using the Life Orientation Test-Revised with subscales for optimism and pessimism. Pearson’s correlation coefficient and multivariate linear regression analysis were applied to investigate the association between optimism and attentional bias. Neither the attentional bias derived from DPT nor EVST was significantly correlated with optimism total score or subscales. Regression analysis also showed no association between attentional bias and optimism (DPT, β = 0.12; EVST, β = 0.09), optimism subscales (DPT, β = 0.09; EVST, β = 0.17), or pessimism subscales (DPT, β = −0.10; EVST, β = 0.02). Our findings showed no evidence that attentional biases derived from either the DPT or EVST measures are associated with optimism or pessimism. Further studies are needed to effectively adapt the ABM to enhance optimism

Endoscopic Treatment of Sinonasal Glomangiopericytoma: A Case Report in Light of the Literature

A 71-year-old Japanese male patient presented with a rare case of Glomangiopericytoma (GPC) of the left nasal with obstruction. Complete resection with endoscopic surgery was performed. Immunohistochemical staining for smooth muscle actin, β catenin, cyclin D1, vimentin, and factor 13 were helpful in establishing a definitive diagnosis. Extranasal treatment has been traditionally performed for successful management. However, recent advances in endoscopic treatment have enabled complete endoscopic resection of GPC, minimizing morbidity and facilitating subsequent surveillance for recurrence. Endoscopic management should be considered in suitable cases

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クマモト ジシン 6カゲツ ニ オケル シュウロウシャ ノ スイミン ト シュカンテキ ケンコウ ジョウタイ ト ノ カンレン ヨウイン

Objective：This study aimed to clarify the relationship between sleep and subjective health condition by focusing on disaster-affected workers six months after the Kumamoto earthquake.Methods：The study population comprised 676 workers at small and medium-sized companies located in Kamimashikigun, Kumamoto Prefecture, where damage after the Kumamoto earthquake was severe. Participants were sent a questionnaire with items related to basic characteristics （sex, age, and family members）, damage to home after the earthquake, subjective symptoms after the earthquake, injury from the earthquakes, changes in income, subjective wellbeing, changes in workload after the earthquake, Athens Insomnia Scale（AIS）, Impact of Event Scale-Revised（IES-R）, General Health Questionnaire（GHQ 28）, and health related QOL Short-Form Health Survey（SF-8）. Responses were collected from 456 people at 13 companies（68.1% response rate）. Of these, 438 responses（96.1%） were valid. This study was approved by the ethical review committee of Fukuoka University School of Medicine.Results：The participants included 334 males and 104 females with an average age of 43.3 years. Two groups were created based on Abbreviated Injury Scale（AIS）scores：279 participants were in the insomnia group and 159 participants were in the non-insomnia group. Compared with that in the non-insomnia group, the patients in the insomnia group were old, had poor subjective health status, and were more likely to have subjective symptoms and injury after the earthquake. The study found a significant positive correlation with intrusion and hyperarousal symptoms in the IES-R subscales. In the SF-8 responses, there were significant negative correlations with BP（Bodily Pain）, GH（General Health）, VT（Vitality）, SF（Social Functioning）, RE（Role Emotional）, MH（Mental Health）, and MCS（Mental Component Summary）. In a logistic regression analysis of sleeping condition in Athens Insomnia Scale（AIS）, BP［OR： 0.942, CI： 0.907-0.978］and avoidance symptoms［OR：0.881, CI：0.799-0.971］improved sleeping condition, whereas hyperarousal symptoms［OR：1.553, CI：1.324-1.823］, social life function［OR：0.954, CI：0.916-0.994］, and daily role function（mental）［OR：0.916, CI：0.866-0.97］were negatively related with good sleeping condition.Discussion：The Kumamoto earthquake influenced the sleep quality for most disaster-affected workers, with approximately 60% reporting insomnia. Because workers with insomnia may exhibit hidden subjective symptoms or suffer from mental stress, long-term preventive systems should be developed and established by companies to improve worker health. Longitudinal studies are required to further examine factors related to sleep condition and outcomes of support systems.原著論文 = Original articl