Lipooligosaccharide locus class of Campylobacter jejuni: sialylation is not needed for invasive infection

Campylobacter jejuni is a highly diverse enteropathogen that is commonly detected worldwide. It can sometimes cause bacteraemia, but the bacterial characteristics facilitating bloodstream infection are not known. A total of 73 C. jejuni isolates, consecutively collected from blood-borne infections during a 10-year period all over Finland and for which detailed clinical information of the patients were available, were included. We screened the isolates by PCR for the lipooligosaccharide (LOS) locus class and for the presence of the putative virulence genes ceuE, ciaB, fucP, and virB11. The isolates were also tested for γ-glutamyl transpeptidase production. The results were analysed with respect to the clinical characteristics of the patients, and the multilocus sequence types (MLSTs) and serum resistance of the isolates. LOS locus classes A, B, and C, which carry genes for sialylation of LOS, were detected in only 23% of the isolates. These isolates were not more resistant to human serum than those with the genes of non-sialylated LOS locus classes, but were significantly more prevalent among patients with underlying diseases (p 0.02). The fucose permease gene fucP was quite uncommon, but was associated with the isolates with the potential to sialylate LOS (p <0.0001). LOS locus classes and some of the putative virulence factors were associated with MLST clonal complexes. Although some of the bacterial characteristics studied here have been suggested to be important for the invasiveness of C. jejuni, they did not explain why the clinical isolates in the present study were able to cause bacteraemia.     

我国主要沿海地区O1群霍乱弧菌分子分型特征分析

目的 采用MLST方法及基质辅助激光解析电离飞行时间质谱(Matrix-assisted laser desorption/ionization time of flight mass spectrometry,MALDI-TOF MS)技术研究我国主要沿海地区192株O1群霍乱弧菌的种群结构、进化趋势及流行特性.方法...     

Clonal distribution of vancomycin-resistant Enterococcus faecium in Turkey and the new singleton ST733

BackgroundThe aim of this study was to provide information about the spread and characteristics of the vancomycin‐resistant Enterococcus faecium isolates (VREfm) in Turkey.MethodsSeventy‐one nonduplicate consecutive isolates of VREfm were obtained from various clinical specimens of inpatients treated at university or training hospitals in seven regions of Turkey. Further characteristics included antibiotic susceptibility testing, pulsed‐field gel electrophoresis (PFGE) of SmaI‐digested genomic DNA, and multilocus sequence typing (MLST) of selected isolates. The presence of vancomycin resistance and virulence genes (esp and hyl) was investigated by polymerase chain reaction (PCR).ResultsAll VREfm isolates had MICs to vancomycin of ≥32 mg/L and contained the vanA gene. The presence of esp gene was identified in 64 and hyl in eight VREfm isolates. All VREfm showed the multiresistance phenotype, including ampicillin (99%), penicillin (99%), imipenem (99%), ciprofloxacin (87%), moxifloxacin (87%), erythromycin (97%), streptomycin (86%), gentamicin (82%), tetracycline (70%), and teicoplanin (99%). All were susceptible to tigecycline while quinupristin‐dalfopristin (97%) and linezolid (93%) were the most active other agents. Analysis of the PFGE profiles showed that 53 (74.6%) VREfm isolates shared a similar electrophoretic profile, designed as type 1, and were closely related (>85%). The sequence type was identified by MLST in 44 VRE isolates with unrelated or closely related PFGE patterns. MLST revealed that nosocomial spread of VREfm resulted from dissemination of lineage C1 E faecium clones. Sequence types ST78, ST203, and ST117 were the most frequently isolated. This is the first report of ST733 around the world.ConclusionsLineage C1 clones are disseminated among clinical VREfm isolates in seven different regions in Turkey. Regarding VREfm isolates, the worldwide epidemic strains are in circulation in Turkey.     

Novel Chlamydia trachomatis Strains in Heterosexual Sex Partners,Indianapolis, Indiana,USA

Chlamydia trachomatis causes a high number of sexually transmitted infections worldwide, but reproducible and precise strain typing to link partners is lacking. We evaluated multilocus sequence typing (MLST) for this purpose by detecting sequence types (STs) concordant for the ompA genotype, a single-locus typing standard. We tested samples collected during April 2000–October 2003 from members of established heterosexual partnerships (dyads) in the Indianapolis, Indiana, USA, area who self-reported being coital partners within the previous 30 days. C. trachomatis DNA from 28 dyads was tested by MLST; sequences were aligned and analyzed for ST and phylogenetic relationships. MLST detected 9 C. trachomatis STs, 4 unique to Indianapolis; STs were identical within each dyad. Thirteen unique strains were identified; 9 (32%) dyads harbored novel recombinant strains that phylogenetically clustered with strains comprising the recombinants. The high rate of novel C. trachomatis recombinants identified supports the use of MLST for transmission and strain diversity studies among at-risk populations.     

Prevalence and molecular characteristics of MRSA nasal carriage among hospital care workers in a tertiary hospital in the Philippines

BackgroundHospital-care workers (HCWs) are at risk for MRSA carriage, subsequent infection and potential transmission of nosocomial infection. Epidemiological typing of MRSA among HCWs would provide data that can be used for control measures.MethodsThis is a cross sectional study that involved 92 participants from pediatric and surgery department of a tertiary hospital. Nasal swabs were collected and inoculated onto MRSASelect Chromogenic Media. Samples characterized as MRSA underwent SCCmec typing and detection of Panton Valentine leucocidin (PVL) by PCR.ResultsThe overall prevalence of MRSA was 13%. Six were from Pediatrics and another six were from Surgery. Seven out of 12 MRSA isolates carried SCCmec type I gene and five isolates carried SCCmec type IV gene. Six samples were found positive for PVL, four of which PVL-SSCmec IV, while the other two isolates were PVL-SCCmec I. The isolates were grouped into four main sequence types (STs) namely ST 1147, ST30, ST5 and ST97. Two samples from both departments were found to be PVL-positive SCCmec I ST 30; PVL-positive SCCmec IV ST 97 was found in two MRSA samples from Pediatrics and PVL-positive SCCmec IV ST 30 from Surgery.ConclusionData collected from a non-outbreak setting suggest the presence of different clones of MRSA from nasal swabs of HCWs belonging to the Department of Pediatrics and Surgery. The data collected by this study can be used as reference for other succeeding studies on the surveillance of MRSA among HCWs.     

The association of pili with the emergence and replacement of the major antibiotic resistant pneumococcal clones

BackgroundThe aim of this study was to evaluate the presence of pilus islet 1 (PI-1) and to determine its clade type in pneumococcal isolates with reduced susceptibility to penicillin (penicillin non-susceptible pneumococci – PNSP) and/or resistant to macrolides isolated prior to and after the introduction of pneumococcal conjugate vaccines (PCVs) in the Czech Republic.MethodsClinical isolates of serotypes 9V (n = 68) and 19A (n = 89) were examined. Isolates were characterised by multilocus sequence typing (MLST). The presence of PI-1 was determined by screening for the sortase B, C, and D genes located within PI-1. In the presence of PI-1 pilus, clade types were classified by PCR.ResultsIn the pre-PCV period (2000–2007), the prevalence of PNSP was 3.9% and 2.7% of isolates were resistant to erythromycin. During 2012–2015 (post-PCV period), the rates of PNSP remained stable (3.6%), but resistance to erythromycin increased to 8.3%. While in 2000–2007, resistance to antibiotics was associated mainly with serotype 9V, in 2012–2015, it was replaced by serotype 19A. PI-1 positive isolates were seen in both serotypes. All isolates (68) of serotype 9V belonged to the Spain^9V-3 (CC156) clone and carried PI-1 of clade type I while 96.5% (56/58) of isolates of 19A serotype belonged to the Netherlands^15B-37 (CC199) clone and carried PI-1 of clade type II.ConclusionsBoth major antibiotic resistant clones carried PI-1, although they differ in the clade type. Thus the role of PI-1 should be evaluated in further studies and potentially considered in the spread of antibiotic resistant clones.     

海港口岸输入性创伤弧菌分离鉴定与分子分型研究

目的对海港口岸输入性创伤弧菌DXV1108进行鉴定和分子分型研究。方法从一艘越南入境船舶的压舱水中分离获得1株病原菌,采用Vitek 2 Compact全自动微生物分析系统进行分类鉴定和抗生素耐药性分析,并采用多位点序列分析(MLST)方法进行分子分型。结果该菌株99%的概率为创伤弧菌,对抗革兰氏阴性菌的抗生素敏感,MLST分析显示为一新发现的序列型。结论本研究对海港口岸防控输入性致病弧菌引发的传染病有重要意义。     

Increase of serotype 8, ST53 clone,as the prevalent strain of Streptococcus pneumoniae causing invasive disease in Madrid,Spain (2012–2015)

IntroductionIn recent years, Streptococcus pneumoniae serotype 8 has become the most prevalent cause of invasive pneumococcal disease (IPD) in Madrid, Spain. The objective of this study was to characterize the invasive clones of S. pneumoniae serotype 8 in Madrid over the 2012–2015 period.MethodsFrom January 2012 to December 2015, a total of 1543 invasive isolates were studied. Serotyping was carried out by Pneumotest-Latex agglutination and Quellung reaction. Susceptibilities to penicillin, erythromycin and levofloxacin were determined by the Etest®. All serotype 8 strains were typed by multilocus sequence typing (MLST) and by pulsed-field gel electrophoresis (PFGE).ResultsTwo hundred and forty-eight (248) serotype 8 strains were detected (16.1%) and 243 of them were available for molecular typing. Nine sequence types (STs) by MLST (8-ST53, 8-ST63, 8-ST404, 8-ST1107, 8-ST989, 8-ST1110, 8-ST2231, 8-ST3544 and 8-ST4301), and nine PFGE profiles were identified (one corresponding to each ST). The 8-ST53 clone was the most widespread, and increased from 53.8% among all serotype 8 isolates in 2012, to 90.1% in 2015. In contrast, the 8-ST63 clone, resistant to levofloxacin and erythromycin, decreased from 30.8%, among all serotype 8 strains in 2012, to 5.0% in 2015.ConclusionsThe increase in our region of S. pneumoniae serotype 8, not included in conjugated vaccines, occurred at the expense of the 8-ST53 clone. On the contrary, the 8-ST63 clone decreased. Since clone 8-ST63 has the theoretical advantage of its levofloxacin-erythromycin resistance in comparison to 8-ST53, the predominance of 8-ST53 over 8-ST63 is striking.     

ICU病区耐碳青霉烯类肺炎克雷伯菌的耐药及同源性特点分析

目的：分析ICU病房耐碳青霉烯类肺炎克雷伯菌（carbapenem?resistant Klebsiella pneumoniae,CRKP）的耐药状况和同源性。方法：收集河南科技大学第一附属医院2018年3—9月肺炎克雷伯菌临床分离株171株。基质辅助激光解析电离飞行时间质谱（MALDI?TOF MS）进行菌株鉴定,琼脂稀释和微量肉汤稀释法检测药物最小抑菌浓度（minimum inhibitory concentration,MIC）值,多位点序列分型（MLST）进行同源性测定,mCIM和eCIM实验进行碳青霉烯酶初筛,β?内酰胺酶、血清荚膜分型基因进行PCR扩增后测序。结果：全院共检出CRKP 68株（39.8%,68/171）,其中ICU病区46株（67.6%,46/68）。46株CRKP对头孢他啶阿维巴坦、替加环素、多黏菌素、米诺环素的耐药率分别为0、0、4.3%、41.7%;菌株在美罗培南、亚胺培南、头孢他啶、氯霉素、磷霉素、氨曲南、环丙沙星MIC90>128;93.5%（43/46）CRKP为ST11型;60.9%（28/46）荚膜血清分型为K47,23.9%（11/46）为K64;46（100%）株均携带blaKPC?2、blaSHV和blaTEM,40株（86.96%）携带blaCTX?M,6株（13.04%）携带blaDHA。结论：该院流行于ICU病区的CRKP菌株以ST11型为主,大多数菌株同时携带blaKPC?2、blaSHV、blaTEM和blaCTX?M。细菌耐药程度高,感染控制部门应重视ICU病区的CRKP传播问题。     

广东省东莞市56株高毒力肺炎克雷伯菌感染分布及分子流行病学研究

目的 研究高毒力肺炎克雷伯菌( hypervirulent Klebsiella pneumoniae, HvKP ) 临床感染分布及菌株间的同源性,分析其分子流行病学特征,为预防和控制高毒力肺炎克雷伯菌的克隆传播提供实验依据。方法 收集东莞市人民医院临床分离非重复的56 株HvKP,应用PCR扩增技术检测其荚膜血清型并测序,运用多位点序列分型(MLST)和肠杆菌科基因间一致重复序列PCR(ERIC—PCR)进行同源性分析,了解其分子流行病学特征。结果 56株HvKP标本来源以呼吸道标本为主,为22株（39.3%）;其次为血液14株（25.0%）;肝脓肿引流液9株（16.1%）,尿液5株（8.9%）,其他标本6株（10.7%）。科室主要分布ICU、普外三区、神经外科二区、综合科;荚膜血清型以Kl、K2、K57型为主,K1、K57型各占25.0%(14/56),K2型略高,占 26.8%(15/56);不同标本类型中,K1在血液标本占比最高,为35.7%（5/14）;K2、K57型主要见于呼吸道标本。ERIC-PCR产物分为22个型别：Ⅰ型10株、Ⅱ 型9株、Ⅲ型7株、Ⅳ型5株、Ⅴ型4株、Ⅵ~Ⅶ各2株、Ⅷ~Ⅸ各2株,其余13个型别各1株;多位点序列分析MLST显示16 种 ST 型,主要以ST23、ST86、 ST218这3种型别为主,其中ST23 全部是 K1型（100.0%） HvKP;不同科室的不同患者高毒力肺炎克雷伯菌进行同源性分析发现,Ⅰ/ST23 K1型居多,其中ICU主要流行Ⅳ/ST23 K1型和Ⅶ/ST11 K54型;普外三区主要流行Ⅰ/ST23 K1型和Ⅱ/ST218 K57型;呼吸科主要流行Ⅰ/ST23 K1型,MLST与ERIC-PCR分析结果有所差别。结论 东莞市HvKP以Ⅰ/ST23 K1型 和以痰液、血液和肝脓肿引流液标本来源为主,应对高毒力肺炎克雷伯菌进行分子流行病学调查,以有效预防和控制HvKP传播。