目的 探讨支气管肺泡灌洗液嗜酸性粒细胞(eosnophils,EOS)、白细胞介素-17(interleukin-17,IL-17)及干扰素-γ(interferon-γ,IFN-γ)与成人哮喘控制水平相关性.方法 选取本院2018年12月—2021年6月收治的51例成人哮喘患者为病例组,同期于本院行气管镜肺泡灌洗检查的20例健康成人作为对照组.获取2组支气管肺泡灌洗液,检测其EOS、IL-17、IFN-γ水平.评估哮喘ACQ-5评分.结果 病例组支气管肺泡灌洗液EOS、IL-17水平高于对照组,差异有统计学意义(P＜0.05);随着哮喘控制程度的下降,支气管肺泡灌洗液EOS、IL-17水平逐渐增加,IFN-γ逐渐下降,差异有统计学意义(P＜0.05);EOS、IL-17与哮喘ACQ-5评分成正相关关系,差异有统计学意义(P＜0.05).IFN-γ与哮喘ACQ-5评分无显著相关性(P＞0.05).受试者工作特征曲线分析显示,IL-17诊断哮喘灵敏度及特异度较高,EOS特异度高,IFN-γ灵敏度高.结论 成人哮喘支气管肺泡灌洗液EOS、IL-17水平升高,IFN-γ下降;EOS、IL-17水平与哮喘控制严重程度密切相关;IL-17协助诊断哮喘有一定帮助,值得在临床上推广应用.

目的:研究血清细胞因子及呼出气一氧化氮（FeNO）在哮喘-慢性阻塞性肺疾病重叠综合征（ACOS）患者中的临床诊治意义。方法:将浙江萧山医院呼吸内科2021年1月至2023年1月收治的65例患者分为支气管哮喘（BA）组（18例），慢性阻塞性肺疾病（COPD）组（18例），ACOS组（29例）。检测3组患者间血清免疫球蛋白E（IgE）、嗜酸性粒细胞（EOS）、中性粒细胞（NE）、FeNO及细胞因子白细胞介素4（IL-4）、IL-5、IL-6、IL-10、IL-13、IL-17、IL-18、肿瘤坏死因子α（TNF-α）水平。采用Pearson相关分析探究FeNO与IgE、EOS、NE及各细胞因子间的相关性。结果:3组患者间IgE（F = 3.343，P = 0.042）、EOS（F = 6.186，P = 0.004）、FeNO（F = 6.560，P = 0.003）、IL-4（F = 10.524，P<0.001）、IL-6（F = 4.637，P = 0.013）、IL-10（F = 2.451，P = 0.018）及TNF-α（F = 11.554，P<0.001）水平比较，差异均有统计学意义。且与COPD组比较，BA组和ACOS组患者的IgE[（129 ± 78）× 103、（250 ± 181）× 103、（238 ± 179）× 103 IU/L]、EOS[（0.12 ± 0.09）× 109/L、（0.35 ± 0.20）× 109/L、（0.25 ± 0.24）× 109/L]、FeNO[（23 ± 8）× 10-9、（49 ± 31）× 10-9、（36 ± 19）× 10-9]、IL-4[（0.029 ± 0.016）、（0.663 ± 0.517）、（0.859 ± 0.815）ng/L]水平均显著升高（P均<0.05），ACOS组TNF-α水平均显著低于COPD组及BA组[（6 ± 4）、（11 ± 3）、（9 ± 4）ng/L，P均<0.05]。Pearson相关分析发现，FeNO与EOS（r = 0.478，P<0.001）、IL-17（r = 0.260，P = 0.036）均呈正相关。结论:ACOS患者的IL-4、IgE、EOS、FeNO水平与BA患者相仿，且高于COPD患者；ACOS患者的TNF-α水平均显著低于单纯BA患者和单纯COPD患者，且FeNO水平与EOS、IL-17均呈正相关。

目的 了解分离 自临床皮肤和软组织感染(SSTIs)患者携带杀白细胞素基因(pvl)社区获得性耐甲氧西林金黄色葡萄球菌(pvl+-CA-MRSA)的分子特征.方法 从SSTIs患者中分离出92株CA-MRSA.采用聚合酶链反应(PCR)和测序检测pvl基因及其突变.pvl+-CA-MRSA菌株进行序列类型(STs)与克隆复合物(CCs)、葡萄球菌盒式染色体mec(SCCmec)、葡萄球菌蛋白基因(spa)多态性、辅助基因调控子(agr)位点、脉冲场凝胶电泳(PFGE)分型和多位点序列分型(MLST).采用VITEK-2 Compact全自动微生物鉴定系统进行CA-MRSA药物敏感试验.结果 92株CA-MRSA中,24株(26.1％)为 pvl+-CA-MRSA,其中 91.7％(22/24)为 pvl 的 H 亚型,68 株(73.9％)为未携带 pvl基因 CA-MRSA(pvl--CA-MRSA).24 株pvl+-CA-MRSA 中,共有 8 种 STs 和 7 种 CCs,其中以 ST59(62.5％,15/24)和 CC59(70.8％,17/24)为主.pvl+-CA-MRSA菌株中,SCCmec Ⅲ和Ⅳa型分别为54.2％和33.3％,agrⅠ(87.5％,21/24)为最常见的agr等位基因,其余为agr Ⅲ;检出8种spa型,其中以t437型最为常见(66.7％,16/24).pvl+-CA-MRSA菌株对红霉素、克林霉素、四环素耐药率较高(均＞50％),对复方新诺明、环丙沙星、庆大霉素的耐药率较低(8.3％～16.7％),未发现万古霉素、利福平、莫西沙星和利奈唑啶耐药菌株.与pvl+-CA-MRSA相比,pvl--CA-MRSA对四环素耐药率较低(P＜0.05),对其它抗菌药物耐药率差异无统计学意义(P＞0.05).结论 引起SSTIs的CA-MRSA中有较高的pvl基因阳性率,pvlH2、ST59/CC59、SCCmec Ⅲ/Iva、agrⅠ 和 t437 是引起 SSTIs CA-MRSA 的优势克隆.

目的 探讨临床分离的耐甲氧西林金黄色葡萄球菌(MRSA)杀白细胞素(pvl)基因亚型的流行及MLST分子分型特征.方法 收集非重复MRSA 287株,按照美国疾病预防控制中心的社区获得性耐甲氧西林金黄色葡萄球菌(CA-MR-SA)定义分为医院获得性耐甲氧西林金黄色葡萄球菌(HA-MRSA)和CA-MRSA两组.采用PCR方法扩增pvl基因,产物双向测序并分析核苷酸变异情况;pvl基因阳性(pvl+)菌株进行多位点序列(MLST)分型并采用eBURST软件进行克隆复合群(CC)分析.结果 287株 MRSA 中,51 株为pvl+菌株(17.8％,51/287),其中29株为 CA-MRSA(56.9％,29/51),22株为HA-MRSA(43.1％,22/51).pvl＋菌株经双向测序共发现4个位点(527、663、1 396和1 729)存在核苷酸变异,根据527位点的差异分为H(H1和H2)和R(R1和R2)亚型.其中46株(90.2％,46/51)为H型(6株H1、40株H2),5株(9.8％,5/51)为 R 型(1 株 R1、4株 R2).H 型主要属于 CC59(ST59/ST388)(69.6％,32/46),其次为 CC22(ST22)(10.9％,5/46),CC1(ST1/ST188)(6.5％,3/46)、CC88(ST88)(4.3％,2/46)、CC5(ST149)(4.3％,2/46)、CC9(ST9)(2.2％,1/46)和 CC30(ST30)(2.2％,1/46);仅在CC59(ST59)、CC88(ST88)和CC5(ST25)型菌株中发现R 型.CA 株和 HA 株携带的pvl均以 H亚型为主,分别占86.2％(25/29)和95.5％(21/22),两组差异无统计学意义.结论 本地区临床分离MRSA携带的pvl以H亚型(H2)为主,主要克隆型别为CC59;CA-MRSA和HA-MRSA携带的pul亚型没有明显差异.

目的 探讨贝伐珠单抗联合靶向治疗对表皮生长因子受体(EGFR)突变型非小细胞肺癌(NSCLC)患者近远期预后及免疫状态、不良反应的影响,以期为临床治疗方法的选择提供参考.方法 选择2017年9月-2018年9月在浙江萧山医院和浙江省邵逸夫医院接受诊治的EGFR突变型NSCLC患者80例,按照随机数字表法分为对照组和观察组,每组各40例.对照组采用盐酸埃克替尼片治疗,观察组采用贝伐珠单抗联合盐酸埃克替尼片治疗.比较2组患者临床疗效、肿瘤标记物水平、免疫指标水平,并对2组患者生存情况、不良反应情况进行比较.结果 观察组疾病控制率(DCR)明显高于对照组(P＜0.05).治疗后,2组血管内皮生长因子(VEGF)、糖类抗原125 (CA125)、细胞角蛋白19片段(CYFRA21-1)水平均明显低于治疗前,且观察组均明显低于对照组(P＜0.05).治疗后,2组CD3+、CD4+/CD8+水平均明显高于治疗前,且观察组均明显高于对照组(P＜0.05).观察组患者的生存情况优于对照组(P＜0.05).观察组不良反应总发生率明显低于对照组(P＜0.05).结论 贝伐珠单抗联合盐酸埃克替尼治疗EGFR突变型NSCLC患者疗效显著,可有效抑制肿瘤细胞增殖,缩小肿瘤体积,改善机体免疫功能,提高患者生存率.

Antibiotics have been described to modulate bacterial virulence gene expression. This study aimed to assess the changes caused by anti-Staphylococcus agents in the transcription of leucocidin ED (lukED) gene of Staphylococcus aureus strain Newman in vitro and in vivo and to determine whether the altered expression is agr dependent. The bacteria were exposed to subinhibitory concentrations [1/2, 1/4, or 1/8 minimal inhibitory concentration (MIC)] of 11 antibiotics, and the expression of lukE and agr-effector RNAIII was determined using qRT-PCR. In vivo experiments were performed to evaluate the impact exerted by six representative antibiotics on the transcription of both genes. Molecular analysis showed that in vitro lukE transcription was dramatically promoted in the Newman strain exposed to sub-MICs of vancomycin, trimethoprim-sulfamethoxazole, clindamycin, gentamicin, daptomycin, and ciprofloxacin and considerably reduced when stimulated by cefazolin, erythromycin, rifampicin, tigecycline, and linezolid. In the murine abscess model, tigecycline significantly decreased the transcription of lukE and the bacterial numbers, whereas vancomycin increased them; although cefazolin increased the lukE expression (contrary to the in vitro effect), it had a remarkable role in reducing bacterial load. The correspondence analysis shows that RNAIII expression varied under seven of 11 antibiotics in vitro, and six drugs in vivo were consistent with lukE transcripts. In conclusion, our data show that anti-Staphylococcus antibiotics exert modulatory effects on lukE expression in vitro and/or in vivo, and the changed expression caused by some drugs may be involved with agr activity, thus providing a guide to choose appropriate agents to avoid promoting bacterial virulence in lukED-positive S. aureus infections.

目的 了解临床分离的淋病奈瑟菌(淋球菌)对阿奇霉素高水平耐药(AZM-HLR)的机制及多序列抗原分型.方法 收集2015-2016年临床分离的淋球菌,采用琼脂稀释法检测阿奇霉素的最小抑菌浓度(MIC),并筛选AZM-HLR(MIC≥256mg/L)菌株,荧光定量聚合酶链反应(PCR)扩增23S rRNA基因及外排系统mtrR编码基因,产物测序分析基因突变特征;淋球菌多抗原序列分型(NG-MAST)方法确定菌株的序列类型(ST).结果 126株淋球菌中,27株阿奇霉素耐药菌株(21.4％,27/126),其中22/27为AZM-HLR,MIC值均为1024mg/L.23S rRNA测序结果显示,所有AZM-HLR菌株均出现等位基因A2059G的突变及mtrR启动子区的13碱基对(bp)反向重复序列内的单碱基位点缺失(△A),19/22存在mtrR编码区G45D突变.NG-MAST结果显示,AZM-HLR菌株中以ST3102和ST1866为主,分别占7/22、6/22.结论 本地区分离的AZM-HLR淋球菌可能与23S rRNA等位基因A2059G突变、mtrR启动子区的13bp反向重复序列内的单碱基位点缺失及mtrR编码区G45D突变有关;ST3102和ST1866是该类菌株的优势型别.

Background The data on the prevalence of resistance to mupirocin (MUP), fusidic acid (FA) and retapamulin (RET) in methicillin-resistant Staphylococcus aureus (MRSA) from China are still limited. This study aimed to examine these three antibiotics resistance in 1206 MRSA clinical isolates from Eastern China. Phenotypic MUP, FA and RET resistance was determined by minimum inhibitory concentrations (MICs), and genotypic by PCR and DNA sequencing of the mupA / B , fusB - D , cfr , vgaA / Av / A LC /B/ C /E, lsaA - C / E and salA and mutations in ileS , fusA / E , rplC , and 23S RNA V domain. The genetic characteristics of resistance isolates were conducted by pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Results Overall MRSA MUP, FA and RET resistance was low (5.1, 1.0 and 0.3%, respectively). MupA was the mechanism of high-level MUP resistance. All low-level MUP resistance isolates possessed an equivocal mutation N213D in IleS; of these, 2 reported an additional V588F mutation with an impact on the Rossman fold. FusA mutations, such as L461K, H457Q, H457Y and V90I were the primary FA mechanisms among high-level resistance isolates, most of which also contained fusC ; however, all low-level resistance strains carried fusB . Except lsaE gene detected in one isolate, no other resistance mechanisms tested were found among RET-resistant isolates. Additionally, sixteen PFGE types (A-P) were observed, among which type B was the most common (49/76, 64.5%), followed by types E and G (4/76, 5.3% each) and types C and M (3/76, 3.9% each). All resistant strains were divided into 15 ST types by MLST. ST764 (24/76, 31.6%), ST630 (11/76, 14.5%), ST239 (9/76, 11.8%) and ST5 (7/76, 9.2%) were the major types. PFGE type B isolates with the aforementioned STs were mainly found in mupirocin resistant isolates. Conclusions MUP, FA and RET exhibited highly activity against the MRSA isolates. Acquired genes and chromosome-borne genes mutations were responsible for MUP and FA resistance; however, the mechanism for some RET-resistant isolates remains to be further elucidated. Also, the surveillance to MUP in MRSA should be strengthened to prevent elevated resistance due to the expansion of clones.

The toxic shock syndrome toxin-1 (TSST-1), encoded by tst gene, has been proposed to cause staphylococcal toxic shock syndrome (TSS) in a susceptible host, which highlights the need to evaluate the level of tst gene expression and molecular genetic characteristics of the tst-positive isolates. A total of 916 S. aureus isolates collected from seven hospitals in China were screened for the tst gene. The tst positive isolates were characterized by spa, SCCmec, PFGE, and agr typing. Representative strains were also subjected to MLST typing. qRT-PCR was used to quantify tst and major virulence regulator genes expression. We also sequenced the regions of promoter and open reading frame (ORF) of tst to investigate whether they correlate with the variation in tst expression. We found 208 (22.7%) of surveyed isolates including 198 (29.8%) of MRSA and 10 (4.0%) of MSSA isolates harbored the tst gene. The most common clone among tst positive MRSA isolates belonged to ST5 (CC5)-agr2-t002-SCCmecII. The amount of tst mRNA varied 8.4-folds among clinical S. aureus isolates. Sequencing the tst promoter revealed a base T deletion in tst high expressed isolates. As for major virulence regulators, srrA, sarT, RNAIII, and ccpA in four tst differentially expressed strains were detected to be highly expressed, respectively. Our study revealed high prevalence of ST5 (CC5)-agr2-t002-SCCmecII clone among tst positive MRSA in hospitals from China. The levels of tst expression among clinical S. aureus isolates varied, which may be associated with tst promoter and variations in specific virulence regulators.

An outbreak of bacillary dysentery occurred in the Xiaoshan Mental Healthcare Center from November 8 to 16, 2012. Eight strains of Shigella flexneri 2a (S. flexneri 2a) were isolated from the same ward. The aim of the investigation was to clarify the origin of outbreak. Rectal swabs or fecal specimens from 7 doctors, 15 nurses, 2 nursing workers, 3 canteen workers, as well as 18 swabs from environmental sample in the ward were screened for Shigella. Phenotypic analysis included standard microbiological identification techniques, serotyping and antimicrobial susceptibility testing. PCR and sequencing were used to characterize drug resistance and virulence genes. Pulsed field gel electrophoresis (PFGE) was carried out for all Shigella isolates. S.flexneri 2a with multidrug resistance was isolated from eight patients and one canteen worker, which carried multiple antibiotics resistance genes and virulence determinants. The results of PFGE confirmed that nine strains of S. flexneri 2a belonged to the same clone. It was suggested that the outbreak strain spread directly from person-person or indirectly from person-food-person from the canteen worker. The outbreak was controlled after quarantine of ill residents, replacement of antibiotics and improvement of hygienic condition.

目的 探讨临床分离的淋病奈瑟菌(淋球菌)对常用抗菌药物的耐药性及分子流行特征.方法 收集2015-2016年本院临床分离的淋球菌,采用琼脂稀释法检测青霉素、四环素、大观霉素、环丙沙星、头孢曲松、头孢克肟、阿奇霉素的最小抑茵浓度(MIC),头孢噻吩纸片法检测产青霉素酶淋球菌(PPNG),淋球菌多抗原序列(NG-MAST)确定菌株的ST.结果 共分离出126株淋球菌,对抗生素的耐药率依次为环丙沙星(100.00％)、青霉素(73.02％)、四环素(65.08％)、阿奇霉素(21.43％),检出17.46％ (22/126)的阿奇霉素高水平耐药(AZ-HLR)(MIC≥256mg/L)菌株,未发现耐大观霉素、头孢曲松、头孢克肟的淋球菌.57.14％(72/126)的菌株为PPNG.NG-MAST分型结果显示,126株淋球菌分为82种不同的STs型别,其中ST1866(6.35％)、ST1927(5.56％)、ST3102(5.56％)是主要ST型,没有明显优势的ST型别.结论 本地区分离的淋球菌存在遗传背景的多样性;阿奇霉素耐药性较高,且发现AZ-HLR菌株,不适合单独治疗淋球菌感染;头孢曲松和大观霉素仍可作为淋病抗感染的一线药物.

目的 通过检测血流感染中大肠埃希菌和肺炎克雷伯菌耐药特征及基因型特征,探讨产ESBLs菌株的流行病学情况,为临床抗感染治疗提供依据.方法 收集浙江萧山医院2015年6月-2017年6月血流感染中大肠埃希菌和肺炎克雷伯菌,进行细菌鉴定和药物敏感试验;对ESBLs阳性菌株进行PCR扩增,明确基因分型.结果 共分离到大肠埃希菌62株,肺炎克雷伯菌46株;产ESBLs检出率分别为48.4％和32.6％.产ESBLs大肠埃希菌和肺炎克雷伯菌对氨苄西林、庆大霉素、复方新诺明、头孢他啶、头孢噻肟、头孢吡肟耐药率较高(＞50％),对磷霉素、哌拉西林/他唑巴坦、头孢哌酮/舒巴坦及阿米卡星耐药率较低(＜20％).基因筛查结果显示,血流感染流行的ESBLs基因型主要为CTX-M型,排在前3位的基因型为CTX-M-14、CTX-M-15和CTX-M-55.结论 血流感染中大肠埃希菌和肺炎克雷伯菌产ESBL比率较高,流行的基因型以CTX-M型为主.

Objectives:Development of resistance in Neisseria gonorrhoeae to ceftriaxone monotherapy or ceftriaxone plus azithromycin dual therapy is a global public health concern. The aim of this study was to analyse the trend in antimicrobial resistance in Hangzhou, China, over the period 2015-17.Methods:In total, 379 clinical isolates were collected from seven hospitals and antimicrobial susceptibility was determined using the agar dilution method. Isolates showing resistance to ceftriaxone, azithromycin or cefixime were analysed for the presence of resistance determinants. STs were determined with the N. gonorrhoeae multiantigen sequence typing (NG-MAST) method and phylogenetic analysis and strain clustering was determined using porB and tbpB sequences.Results:Ceftriaxone resistance, decreased susceptibility to ceftriaxone and azithromycin resistance were observed in 3%, 17% and 21% of the isolates, respectively. This resulted in 5% of the isolates showing both decreased susceptibility to ceftriaxone and azithromycin resistance. Importantly, resistance levels to ceftriaxone and azithromycin increased over the study period, resulting in 5% ceftriaxone resistance, 27% decreased susceptibility to ceftriaxone and 35% azithromycin resistance in 2017 and 11% of the isolates showing both decreased susceptibility to ceftriaxone and azithromycin resistance. Phylogenetic and cluster analysis showed the emergence and expansion in 2017 of a clonally related cluster containing strains with high abundance of decreased susceptibility to ceftriaxone and/or cefixime, which was related to the presence of the mosaic penA allele X. Co-resistance to azithromycin was also observed in this cluster.Conclusions:Our findings have major implications for the future reliability of ceftriaxone monotherapy and ceftriaxone plus azithromycin dual therapy in China.

目的 研究产ESBLs肺炎克雷伯菌血流感染现状及其危险因素.方法 通过病原菌分离鉴定和药敏试验方法,对某医院住院患者肺炎克雷伯菌血流感染病例现状进行调查与分析.结果 共调查肺炎克雷伯菌血流感染病例75例,分离到肺炎克雷伯菌75株,其中产ESBLs菌株占30.7％.产ESBLs肺炎克雷伯菌对庆大霉素、氨苄西林、复方新诺明、头孢他啶、头孢噻肟和头孢吡肟耐药率均达50％以上;临床分离的肺炎克雷伯菌中已经产生耐碳青霉烯类菌株;近3个月内有手术史和住院史易引发肺炎克雷伯菌感染.结论 血流感染的肺炎克雷伯菌中产ESBLs比率较高,临床用药前应评估危险因素,合理选用抗菌药物.

The amount of Panton-Valentine leukocidin (PVL) is diverse among Staphylococcus aureus isolates from different geographical regions, and its significance in some infections is disputed. However, data concerning this information in China are limited. Fifty-one lukSF-PV+ methicillin-resistant Staphylococcus aureus (MRSA) isolates gathered from varying infections were used for PVL production using enzyme-linked immunosorbent assay, and the quantity was analyzed in correlation with PVL isoform, genetic background of the isolate, and disease category. All isolates generated PVL with a range of 0.43–360.87 μg/mL, of which 56.9% isolates (29/51) generated 51–200 μg/mL of PVL; 11.8% (6/51) yielded PVL more than 200 μg/mL, and the rest (31.4%, 16/51) produced PVL of ≤50 μg/mL. The amount of PVL was not related to its variant and infection type, although isolates from skin and soft tissue infection had relatively high mean and median. Clonal complex (CC) 22 isolates might be the producer of relatively high concentrations of PVL; however, the difference among CCs was not analyzed due to a small number of CC isolates. The relevance of PVL production with the infection type, toxin isoform, and genetic characteristic of isolates may vary by clone type and also needs to be further evaluated using a large sample size and best concentration on in vivo environment.

Objective To investigate the epidemic of ESBLs - producing Escherichia coli in bloodstream infections. And to analyze the risk factors of ESBLs - producing Escherichia coli infections, in order to provide laboratory evidence to the clinical. Methods The Escherichia coli in bloodstream infections were collected from January 2012 to December 2016 in Xiaoshan Hospital for bacterial identification and drug sensitivity test. The risk factors of ESBLs - producing Escherichia coli infections were analyzed. Results A total of 236 pathogens were collected, and Escherichia coli producing ESBLs accounted for 47.9％. ESBLs - producing Escherichia coli strains were resistant to gentamycin, ampicillin, ciprofloxacin, levofloxacin, cotrimoxazole, ceftazidime, cefotaxime and cefepime (with the positive rate more than 50％). The resistance rate to fosfomycin, piperacillin/tazobactam, cefoperazone/sulbactam and amikacin was low (＜10％). The risk factors of bloodstream infection caused by ESBLs - producing Escherichia coli included basic diseases, obstructive urinary tract disease, malignant neoplasms, hospital history in nearly 3 months and the antimicrobial use in nearly 3 months. Conclusion ESBLs - producing Escherichia coli in bloodstream infection has high detection rate, and there are many risk factors of bloodstream infections caused by ESBLs - producing Escherichia coli. We should assess the risk factors in the course of clinical medication.

Objective To isolate and identify the methicillin-resistant Staphylococcus aureus (MRSA) strains carrying Panton-Valentine leukocidin genes (pvl+-MRSA) from clinical samples and to further understand their molecular characteristics and infections caused by them.Methods Drug susceptibility test was performed to detect the drug resistance in 259 MRSA strains.pvl+-MRSA strains were screened out from those MRSA strains using cefoxitin slip test and mecA gene detection by PCR.Multiple PCR and multilocus sequence typing (MLST) were used for SCCmec and ST typing.Pulsed-field gel electrophoresis (PFGE) and cluster analysis were used to understand the genetic and epidemic features of the pvl+-MRSA strains.Different types of infections and diseases caused by the pvl+-MRSA strains were analyzed.ResultsAmong the 259 MRSA strains, 51 pvl+-MRSA strains were identified (19.7%, 51/259), of which 29 and 22 strains were respectively isolated from patients with community-acquired and hospital-acquired infections.ST59-SCCmecⅢ (35.3%, 18/51) was the predominant type of the 51 pvl+-MRSA strains, followed by ST59-SCCmecⅣ(25.5%, 13/51).But no predominant clone among those strains was revealed by the result of PFGE.Children, young-and middle-aged patients (≤44 years old) had a significantly higher positive rate of pvl+-MRSA than patients aged ≥45 years (P<0.05).Skin and soft tissue infection (47.1%, 24/51) was the most common disease caused by the pvl+-MRSA strains (P<0.05), followed by pneumonia (17.6%, 9/51).The pvl+-MRSA strains showed lower resistance to levofloxacin, gentamycin and rifampicine (7.8%-21.6%).No moxifloxacin-, nitrofurantoin-or linezolid-resistant pvl+-MRSA strains were identified.Conclusion The rate of pvl+-MRSA infection is high in the local population.ST59-SCCmecⅢ and ST59-SCCmecⅣ are the predominant types of pvl+ MRSA strains.Children, young-and middle-aged persons are the susceptible population.Skin and soft tissue infection and pneumonia are the common diseases caused by pvl+-MRSA.

The Panton-Valentine leukocidin (PVL) genes of methicillin-resistant Staphylococcus aureus (MRSA) have previously been associated with severe infections. Here, the impact of the PVL genes on severity of disease and clinical outcome of patients with hospital-acquired pneumonia (HAP) or ventilator-associated pneumonia (VAP) due to MRSA was investigated in a single center observational study in a hospital in China. HAP due to MRSA was diagnosed in 100 patients and 13 of the patients were PVL positive, while VAP was diagnosed in 5 patients and 2 were PVL positive. The PVL positive patient group showed a significantly higher Acute Physiology and Chronic Health Evaluation (APACHE) II score (14.3 ±7.8 vs. 10.1 ±4.7, P = 0.005) and significantly more patients with CRP levels >80 mg/L (8/15 vs. 12/90, P = 0.006) or WBC counts >15x109/L (7/15 vs. 12/90, P = 0.006), indicating that the severity of disease is affected by the presence of the PVL genes. The outcome of the study was defined by 30-day mortality. Four (27%) of the PVL positive patients and four (4%) of the PVL negative patients died within 30 days (P = 0.01, Fisher exact test). Kaplan-Meier survival curves were generated for the PVL positive and PVL negative patient groups, which differed significantly (P = 0.003). Among the patients that died, the mean interval between diagnosis and death was shorter for the PVL positive patients (9.3 ±5.6 vs. 40.8 ±6.6 days, P = 0.013). Further analysis within the HAP and VAP patient groups showed that the presence of PVL in MRSA impacted the severity of disease and clinical outcome of HAP, but for VAP the number of patients included in the study was too low. In conclusion, in this single center study in a Chinese hospital the presence of the PVL genes in MRSA impacted the severity of disease and clinical outcome in patients with HAP due to MRSA.

目的 了解耐甲氧西林金黄色葡萄球菌(MRSA)临床菌株携带杀白细胞毒素(PVL)编码基因pvl和中毒休克综合征毒素-1(TSST-1)编码基因tst情况、流行特征及感染类型,为该类感染的临床治疗提供依据.方法 收集2012年1-12月临床分离的MRSA 96株,采用PCR检测96株MRSA中pvl和tst基因,采用全自动微生物分析仪检测11种临床常用抗菌药物的敏感性,采用多重PCR对携带pvl基因(pvl+)或tst基因(tst+)的MRSA进行mac分型(SCCmec),了解与分析pvl+或tst+ MRSA感染类型.结果 96株MRSA中20株检出pvl基因占20.8％,13株检出tst基因占13.5％,未发现同时携带pvl和tst基因的菌株;除左氧氟沙星和莫西沙星外,pvl+/tst+ MRSA对其他抗菌药物耐药率与pvl-/tst-菌株相似;20株pvl+ MRSA中7株社区获得性感染菌株、13株医院获得性感染菌株,其中17株分离自皮肤和软组织感染患者脓液,13株tst+ MRSA均为医院获得感染菌株,其中8株分离自肺部感染患者痰液;20株pvl+ MRSA中,SCCmecⅢ型11株、SCCmecⅣa型5株、SCCmecⅡ型2株,2株未能分型;13株tst+ MRSA均为SCCmecⅢ型.结论 pvl+ MRSA在社区和医院内均有流行,主要引起皮肤和软组织感染;tst+ MRSA仅在医院内流行,主要引起肺部感染;pvl+和tst+ MRSA均以SCCmecⅢ型为主.