儿童呼吸道卡他莫拉菌分离株产β-内酰胺酶情况和耐药性以及菌株BRO酶基因特征

目的研究儿童呼吸道卡他莫拉菌分离株产β-内酰胺酶情况和耐药性以及菌株BRO酶基因特征。方法选择2016年2月-2019年1月因呼吸道感染就诊且从痰液标本中分离得到卡他莫拉菌的患儿,测定抗生素敏感性、产β-内酰胺酶情况、BRO酶基因表达情况。结果产酶菌株对氨苄西林、阿莫西林、头孢克洛、头孢呋辛、头孢吡肟、左氧氟沙星、克拉霉素产生耐药的发生率高于非产酶菌株,BRO-1基因阳性菌株对氨苄西林、阿莫西林、头孢克洛、头孢呋辛、头孢吡肟、左氧氟沙星、克拉霉素产生耐药的发生率高于BRO-2基因阳性菌株;产酶菌株和非产酶菌株、BRO-1基因阳性和BRO-2基因阳性菌株均对亚胺培南敏感,未发生耐药。结论儿童呼吸道卡他莫拉菌产β-内酰胺酶比例高,且BRO-1基因阳性菌株的耐药性强于BRO-2基因阳性菌株。     

成都地区儿童下呼吸道感染卡他莫拉菌的特点及耐药性分析

目的:研究成都地区儿童下呼吸道感染中卡他莫拉菌的感染情况,为临床诊断和合理使用抗生素提供参考。方法:收集 2018 年2 月至2020 年1 月四川省骨科医院和成都市妇女儿童中心医院儿科送检的15 891 例0~14 岁下呼吸道感染患儿的痰 液标本,进行卡他莫拉菌的鉴定和药敏试验并进行统计分析。结果:15 891 例痰标本中共检出卡他莫拉菌3 333 株,总检出率 为20. 97%;感染卡他莫拉菌的患儿无性别差异(P>0. 05);卡他莫拉菌在>1~3 岁年龄组中检出率最高,≤28 d 年龄组检出率最 低;不同季节卡他莫拉菌的检出率结果比较差异有统计学意义(P<0. 05),其中冬季检出率最高,夏季检出率最低;卡他莫拉菌 的β-内酰胺酶阳性率为98. 47%,对阿莫西林/ 克拉维酸、头孢噻肟、氧氟沙星、四环素、氯霉素和利福平的敏感率均>90%。结 论:1~6 岁儿童在冬季容易感染卡他莫拉菌,且在轻痉肺炎中检出率最高,β-内酰胺酶阳性率达98. 47%,阿莫西林/ 克拉维酸、 头孢噻肟可以作为治疗的首选药,临床医师可以参考卡他莫拉菌的感染特点和耐药情况进行诊疗和临床用药。     

肺炎支原体肺炎患儿口咽部常见细菌及临床意义北大核心CSCD

目的:了解肺炎支原体肺炎(MPP)患儿口咽部常见细菌及临床意义。方法:回顾性分析。选取中国医科大学附属盛京医院小儿呼吸内科2016年12月至2017年6月住院治疗的134例MPP患儿为研究对象,选取同期同医院42例健康儿童为健康对照组。采用荧光定量聚合酶链反应Taqman探针法检测入组儿童口咽部常见细菌[肺炎链球菌(SP)、卡他莫拉杆菌(CTA)、流感嗜血杆菌(HI)]。首先比较MPP患儿及健康儿童口咽部细菌检出情况,再将134例MPP患儿根据年龄(<1岁、1~<3岁、3~<6岁及6~14岁)、有无细菌检出[肺炎支原体(MP)、MP+细菌]及检出菌种不同(MP+SP、MP+CTA及MP+HI)进行分组比较。采用秩和检验及 χ^(2)检验对相关临床资料进行分析。 结果:134例MPP患儿检出细菌79例(58.96%),42例健康儿童检出细菌17例(40.48%),差异有统计学意义( χ^(2)=4.404, P<0.05)。与MP组相比,MP+细菌组外周血中白细胞(WBC)水平[8.5(6.7,12.0)×10^(9)/L比7.8(5.8,9.3)×10^(9)/L, Z=-2.232]、C反应蛋白(CRP)水平[19.2(7.2,35.0) mg/L比8.4(3.4,24.6) mg/L, Z=-2.810]、乳酸脱氢酶(LDH)水平[286(244,365) U/L比250(210,302) U/L, Z=-2.474]及大叶性肺炎比例[40.51%(32/79例)比18.18%(10/55例), χ^(2)=7.510]、胸腔积液比例[13.92%(11/79例)比3.64%(2/55例), χ^(2)=3.917]、难治性肺炎支原体肺炎(RMPP)比例[34.18%(27/79例)比18.18%(10/55例), χ^(2)=4.151]均较高;总热程[10(7,12) d比8(6,10) d, Z=-2.706]及抗生素使用时间[16(13,19) d比12(9,16) d, Z=-3.747]均较长,差异均有统计学意义(均 P<0.05)。MP+SP组外周血中WBC高于MP+HI组[12.20(7.80,17.30)×10^(9)/L比6.75(5.37,9.44)×10^(9)/L],差异有统计学意义( Z=11.574, P<0.05);MP+SP组[56.67%(17/30例)]大叶性肺炎发生率高于MP+CTA组[0(0/3例)]和MP+HI组[18.75%(3/16例)],差异有统计学意义( χ^(2)=9.770, P<0.05)。 结论:MPP患儿口咽部更易发生细菌定植或感染,当WBC、CRP及LDH均明显升高,影像表现为大片实变影或有胸腔积液时,提示可能混合细菌感染,热程更长,难治性MPP比例增高,且常见的混合细菌为SP。     

Airway microbiota and acute respiratory infection in children

Acute respiratory infections (ARIs), such as bronchiolitis and pneumonia, are the leading cause of hospitalization of infants in the US. While the incidence and severity of ARI can vary widely among children, the reasons for these differences are not fully explained by traditional risk factors (e.g., prematurity, viral pathogens). The recent advent of molecular diagnostic techniques has revealed the presence of highly functional communities of microbes inhabiting the human body (i.e., microbiota) that appear to influence development of local and systemic immune response. We propose a ‘risk and resilience’ model in which airway microbiota are associated with an increased (risk microbiota) or decreased (resilience microbiota) incidence and severity of ARI in children. We also propose that modulating airway microbiota (e.g., from risk to resilience microbiota) during early childhood will optimize airway immunity and, thereby, decrease ARI incidence and severity in children.     

Susceptibility of clinical Moraxella catarrhalis isolates in British Columbia to six empirically prescribed antibiotic agents

BACKGROUND:

Moraxella catarrhalis is a commensal organism of the respiratory tract that has emerged as an important pathogen for a variety of upper and lower respiratory tract infections including otitis media and acute exacerbations of chronic bronchitis. Susceptibility testing of M catarrhalis is not routinely performed in most diagnostic laboratories; rather, a comment predicting susceptibility based on the literature is attached to the report. The most recent Canadian report on M catarrhalis antimicrobial susceptibility was published in 2003; therefore, a new study at this time was of interest and importance.

OBJECTIVE:

To determine the susceptibility of M catarrhalis isolates from British Columbia to amoxicillin-clavulanate, doxycycline, clarithromycin, cefuroxime, levofloxacin and trimethoprimsulfamethoxazole.

METHODS:

A total of 117 clinical M catarrhalis isolates were isolated and tested from five Interior hospitals and two private laboratory centres in British Columbia between January and December 2012. Antibiotic susceptibility of M catarrhalis isolates was characterized using the Etest (E-strip; bioMérieux, USA) according to Clinical Laboratory Standards Institute guidelines.

RESULTS:

All isolates were sensitive to amoxicillin-clavulanate, doxycycline, clarithromycin, levofloxacin and trimethoprimsulfamethoxazole. One isolate was intermediately resistant to cefuroxime, representing a 99.15% sensitivity rate to the cephem agent. Cefuroxime minimum inhibitory concentrations (MICs) inhibiting 50% and 90% of organisms (MIC50 and MIC90) were highest among the antibiotics tested, and the MIC90 (3 μg/mL) of cefuroxime reached the Clinical Laboratory Standards Institute breakpoint of susceptibility.

DISCUSSION:

The antibiotic susceptibility of M catarrhalis isolates evaluated in the present study largely confirms the findings of previous surveillance studies performed in Canada. Cefuroxime MICs are in the high end of the sensitive range and the MIC50 and MIC90 observed in the present study are the highest ever reported in Canada.

CONCLUSION:

Although cefuroxime MICs in M catarrhalis are high, all agents tested showed antimicrobial activity, supporting their continued therapeutic and empirical use.     

A rare case of Moraxella lacunata producing combined native mitral and aortic valve endocarditis

We describe a case of infective endocarditis due to Moraxella lacunata involving the native mitral and aortic valves, complicated by cerebral emboli and resultant hemiparesis. The patient was treated with ceftriaxone and gentamicin and improved. This appears to be the first case reported in the medical literature of native multivalvular endocarditis produced by this rare organism.     

2000～2002年患儿呼吸道致病菌的耐药性研究

目的　研究 2 0 0 0～ 2 0 0 2年上海地区患儿呼吸道流感嗜血杆菌、肺炎链球菌及卡他莫拉菌感染情况 ,肺炎链球菌的血清分型 ,3种致病菌对抗菌药物的耐药情况。方法　细菌的生化鉴定采用API鉴定系统 ,肺炎链球菌血清分型采用荚膜肿胀试验 ,β内酰胺酶测定采用头孢硝噻酚试验 ,抗生素敏感试验采用浓度梯度扩散法及琼脂扩散法。结果　流感嗜血杆菌持续 3年位居呼吸道致病菌首位 ,对氨苄西林素耐药率接近 2 0 %。卡他莫拉菌及肺炎链球菌分离率呈增加趋势 ,其中 17 2 %流感嗜血杆菌及 95 1%卡他莫拉菌 β内酰胺酶阳性。 72 7% β内酰胺酶阳性卡他莫拉菌对氨苄西林耐药。检测到 11种肺炎链球菌血清型 ,19F及 2 3F为主要血清型 ,青霉素耐药菌株 (PRSP)占 4 2 %。结论　流感嗜血杆菌、卡他莫拉菌及肺炎链球菌已成为上海地区患儿呼吸道主要院外感染致病菌。流感嗜血杆菌、肺炎链球菌感染对青霉素类抗生素已产生不同程度的耐药 ,19F、2 3F是本地区肺炎链球菌主要血清型。     

大环内酯类耐药卡他莫拉菌23S rRNA基因突变位点与临床特点分 析

目的:研究大环内酯类耐药卡他莫拉菌的临床特点、药敏及耐药机制。方法:留取住院社区获得性下呼吸道感染患儿痰标本分离48株卡他莫拉菌,建株保存,分析卡他莫拉菌对大环内酯类敏感及耐药患儿的临床特点;采用K-B法进行药敏试验,头孢硝噻吩色原法测定茁鄄内酰胺酶,聚合酶链反应(PCR)及序列分析大环内酯类耐药机制。结果: 48株卡他莫拉菌β-内酰胺酶的产酶率为93.8%(45/48);卡他莫拉菌对红霉素和阿奇霉素耐药率分别为56.3%和41.7%。在23S rRNA突变位点检测中,A2982T、C3132T 等突变位点与大环内酯类耐药可能有关,未发现ermA、ermB、mefA 及merE等耐药基因。耐药组更多表现为喘息、肺部喘鸣音,与敏感组比较差异有统计学意义(P<0.05)。结论:卡他莫拉菌β-内酰胺酶的产酶率、对大环内酯类的耐药性均日益增加,大环内酯类耐药组患儿更多表现为喘息,卡他莫拉菌耐药机制可能与23S rRNA位点发生突变有关。