猪源肠外致病性大肠杆菌的分离与鉴定

目的 检测猪源肠外致病性大肠杆菌(ExPEC)的血清型与毒力基因。方法 对2013-2014年间秦皇岛地区30 份组织病料采用细菌形态观察、培养特性试验、生化试验鉴定出8株肠外致病性大肠杆菌。采用玻片凝集法测定这些大肠杆菌病的血清型,并用PCR扩增法检测9种毒力基因。结果 定型菌株5株,分别属于O53、O93和 O157 3个血清型,9 种毒力基因 PCR 检测结果表明ler、iutA、irp2、fyuA、astA 5种基因检出率分别为100%、75.0%、50.0%、50.0%、25.0%。结论 所检测的猪源肠外致病性大肠杆菌以O53、O93 和O157 为主要流行血清型,同时携带fyuA、ler和iutA基因的菌株致病性较强。     

Characterization of Anti-Bacterial Effect of the Two New Phages against Uropathogenic Escherichia coli

Urinary tract infections (UTIs) are among the events that most frequently need medical intervention. Uropathogenic Escherichia coli are frequently their causative agents and the infections are sometimes complicated by the presence of polyresistant nosocomial strains. Phage therapy is a tool that has good prospects for the treatment of these infections. In the present study, we isolated and characterized two bacteriophages with broad host specificity against a panel of local uropathogenic E. coli strains and combined them into a phage cocktail. According to genome sequencing, these phages were closely related and belonged to the Tequatrovirus genus. The newly isolated phages showed very good activity on a panel of local clinical E. coli strains from urinary tract infections. In the form of a two-phage cocktail, they were active on E. coli strains belonging to phylogroups B2 and D, with relatively lower activity in B1 and no response in phylogroup A. Our study is a preliminary step toward the establishment of a national phage bank containing local, well-characterized phages with therapeutic potential for patients in Slovakia.     

Domain activities of PapC usher reveal the mechanism of action of an Escherichia coli molecular machine

P pili are prototypical chaperone-usher pathway-assembled pili used by Gram-negative bacteria to adhere to host tissues. The PapC usher contains five functional domains: a transmembrane β-barrel, a β-sandwich Plug, an N-terminal (periplasmic) domain (NTD), and two C-terminal (periplasmic) domains, CTD1 and CTD2. Here, we delineated usher domain interactions between themselves and with chaperone-subunit complexes and showed that overexpression of individual usher domains inhibits pilus assembly. Prior work revealed that the Plug domain occludes the pore of the transmembrane domain of a solitary usher, but the chaperone-adhesin-bound usher has its Plug displaced from the pore, adjacent to the NTD. We demonstrate an interaction between the NTD and Plug domains that suggests a biophysical basis for usher gating. Furthermore, we found that the NTD exhibits high-affinity binding to the chaperone-adhesin (PapDG) complex and low-affinity binding to the major tip subunit PapE (PapDE). We also demonstrate that CTD2 binds with lower affinity to all tested chaperone-subunit complexes except for the chaperone-terminator subunit (PapDH) and has a catalytic role in dissociating the NTD-PapDG complex, suggesting an interplay between recruitment to the NTD and transfer to CTD2 during pilus initiation. The Plug domain and the NTD-Plug complex bound all of the chaperone-subunit complexes tested including PapDH, suggesting that the Plug actively recruits chaperone-subunit complexes to the usher and is the sole recruiter of PapDH. Overall, our studies reveal the cooperative, active roles played by periplasmic domains of the usher to initiate, grow, and terminate a prototypical chaperone-usher pathway pilus.     

Zoonotic potential of multidrug-resistant extraintestinal pathogenic Escherichia coli obtained from healthy poultry carcasses in Salvador,Brazil

The zoonotic potential to cause human and/or animal infections among multidrug-resistant extraintestinal pathogenic Escherichia coli from avian origin was investigated. Twenty-seven extraintestinal pathogenic E. coli isolates containing the increased survival gene (iss) were obtained from the livers of healthy and diseased poultry carcasses at two slaughterhouses in Salvador, northeastern Brazil. The antimicrobial resistance-susceptibility profiles were conducted with antibiotics of avian and/or human use by the standardized disc-diffusion method. Antimicrobial resistance was higher for levofloxacin (51.8%), amoxicillin/clavulanic acid (70.4%), ampicillin (81.5%), cefalotin (88.8%), tetracycline (100%) and streptomycin (100%). The minimum inhibitory concentrations above the resistance breakpoints of doxycycline, neomycin, oxytetracycline and enrofloxacin reached, respectively, 88.0%, 100%, 75% and 91.7% of the isolates. Strains with high and low antimicrobial resistance were i.p. administered to Swiss mice, and histopathological examination was carried out seven days after infection. Resistance to goat and human serum complement was also evaluated. The results show that Swiss mice challenged with strain 2B (resistant to 11 antimicrobials) provoked a severe degeneration of hepatocytes besides lymphocytic infiltration in the liver, whereas the spleen showed areas of degeneration of the white and red pulp. Conversely, the spleen and liver of mice challenged with strain 4A (resistant to two antimicrobials) were morphologically preserved. In addition, complement resistance to goat and human serum was high for strain 2B and low for strain 4A. Our data show that multidrug resistance and pathogenesis can be correlated in extraintestinal pathogenic E. coli strains obtained from apparently healthy poultry carcasses, increasing the risk for human public healthy.     

Fluoroquinolone-resistant Escherichia coli in the long-term care setting

Background

Prior studies have found fluoroquinolone exposure to be a risk factor for infection with fluoroquinolone-resistant gram-negative rods in the acute care setting. However, risk factors may be different in the long-term care setting.

Methods

A case-control study design was used to determine whether fluoroquinolone exposure is a risk factor for fluoroquinolone-resistant Escherichia coli urinary tract infections in a long-term care center. Cases had fluoroquinolone-resistant E. coli urinary tract infections; 4 controls were selected for each case.

Results

Thirty-three case patients were eligible; 132 controls were then selected. In the multivariable analysis, fluoroquinolone-resistant E. coli urinary tract infection was more common with prior fluoroquinolone use (odds ratio 21.8, 95% confidence interval, 3.7-127.1).

Conclusions

Prior fluoroquinolone use is a strong risk factor for fluoroquinolone-resistant E. coli urinary tract infection in the long-term care setting. Further studies are needed to examine the effect of interventions to decrease fluoroquinolone-resistant infections in the long-term care setting, including studying the effect of decreasing fluoroquinolone use.     

P菌毛粘附素在致肾盂肾炎大肠埃希菌对小鼠尿道上行感染中的作用

目的 比较2株具有不同P菌毛粘附素(PapG)的同血清型UPEC和1株无菌毛大肠埃希菌对小鼠泌尿道上行感染性的差异,探讨粘附素在UPEC尿道感染中的作用。方法 通过17PEC尿道内接种形成BALB/c小鼠尿道上行感染;观察尿液、肾脏剖面的菌落计数和肾组织的病理改变。结果 具有P菌毛的UPEC菌株感染之小鼠,在其尿液和肾剖面培养出大量原感染菌,肾组织呈现中、重度急性肾盂肾炎的病理改变;不同P菌毛粘附素的UPEC感染的菌落计数、肾脏病理改变严重度无显著性差异;无菌毛大肠埃希菌感染之小鼠,其尿液和肾剖面只有少量原感染茵生长,肾组织为轻至中度急性炎症改变。结论具有不同粘附素之P菌毛在介导UPEC致小鼠上行性急性肾盂肾炎中均发挥重要作用;无菌毛大肠埃希菌亦可导致小鼠肾脏炎性改变。     

老年下呼吸道感染患者肺炎克雷伯菌和大肠埃希菌耐药性分析

目的：监测老年下呼吸道感染患者肺炎克雷伯菌和大肠埃希菌的耐药性。为临床合理应用抗生素提供依据。方法：对我院下呼吸道感染患者中分离出的肺炎克雷伯菌和大肠埃希菌240株，以Kirby-Bauer(K-B)琼脂扩散法作药敏试验；以美国临床实验室标准委员会（NCCLS）1999年推荐的表型确认试验检测超广谱β－内酰胺酶（ESBLs）。结果：老年组和非老年组肺炎克雷伯菌和大肠埃希菌对14例抗生素的耐药率分别为阿莫西林93．2％和87．3％，哌拉西林57．1％和42．9％、头孢呋新51．4％和33．3％、头孢噻肟40．1％和17．5％、头孢他啶13．6％和3．2％、头孢曲松39．0％和17．5％、头孢哌酮37．3％和15．9％，头孢吡肟10．2％和3．2％、阿米卡星47．5％和34．9％，环丙沙星54．2％和38．1％、亚胺培南15．9％、头孢吡肟10．2％和3．2％、阿米卡星47．5％和34．9％、环丙沙星54．2％和38．1％，亚胺培南0和0、头孢哌酮／舒巴坦0和0、哌拉西林／三唑巴坦1．1％和0、头孢美唑9．6％和4．8％。78株肺炎克雷伯菌和大肠埃希菌被证实为产ESBLs菌，ESBLs检测出率为32．5％（78／240），其中老年组ESBLs检出率为38．4％（68／177），非老年组ESBLs检出率为15．9％（10／63）。亚胺培南，头孢哌酮／舒巴坦，哌拉西林／三唑巴坦和头孢美唑对产ESBLs菌的耐药率最低，分别为0、0、2．6％和12．8％。结论：老年下呼吸道感染患者肺炎克雷伯菌和大肠埃希菌的耐药率和ESBLs检出率均显著高于非老年患者；亚胺培南，头孢哌酮／舒巴坦、哌拉西林／三唑巴坦和头孢美唑是治疗由产ESBLs菌引起感染的有效抗生素。     

Hamiltonella defensa,genome evolution of protective bacterial endosymbiont from pathogenic ancestors

Eukaryotes engage in a multitude of beneficial and deleterious interactions with bacteria. Hamiltonella defensa, an endosymbiont of aphids and other sap-feeding insects, protects its aphid host from attack by parasitoid wasps. Thus H. defensa is only conditionally beneficial to hosts, unlike ancient nutritional symbionts, such as Buchnera, that are obligate. Similar to pathogenic bacteria, H. defensa is able to invade naive hosts and circumvent host immune responses. We have sequenced the genome of H. defensa to identify possible mechanisms that underlie its persistence in healthy aphids and protection from parasitoids. The 2.1-Mb genome has undergone significant reduction in size relative to its closest free-living relatives, which include Yersinia and Serratia species (4.6–5.4 Mb). Auxotrophic for 8 of the 10 essential amino acids, H. defensa is reliant upon the essential amino acids produced by Buchnera. Despite these losses, the H. defensa genome retains more genes and pathways for a variety of cell structures and processes than do obligate symbionts, such as Buchnera. Furthermore, putative pathogenicity loci, encoding type-3 secretion systems, and toxin homologs, which are absent in obligate symbionts, are abundant in the H. defensa genome, as are regulatory genes that likely control the timing of their expression. The genome is also littered with mobile DNA, including phage-derived genes, plasmids, and insertion-sequence elements, highlighting its dynamic nature and the continued role horizontal gene transfer plays in shaping it.     

Emergence of and risk factors for ciprofloxacin-gentamicin-resistant Escherichia coli urinary tract infections in a region of Quebec

BACKGROUND:

An increased incidence of urinary tract infections (UTIs) caused by ciprofloxacin-gentamicin-resistant Escherichia coli (CiGREC) has been observed in a tertiary care centre in Sherbrooke, Quebec. The risk factors for such infections remained unclear.

METHODS:

To determine risk factors for, and outcomes of, CiGREC UTIs, a case control study was conducted. Between 2000 and 2007, 93 cases and 186 controls were identified using laboratory records of patients with greater than 10⁷ colony-forming units/L of E coli in a urinary specimen. Cases had E coli with minimum inhibitory concentration to ciprofloxacin of 4 mg/L or greater and minimum inhibitory concentration to gentamicin of 8 mg/L or greater (CiGREC), and controls had E coli with any other susceptibility pattern to ciprofloxacin and gentamicin. Clinical and laboratory data were collected. Adjusted odds ratios (AOR) and their 95% CIs were calculated by logistic regression.

RESULTS:

The prevalence of CiGREC increased sixfold during the study period. Risk factors associated with CiGREC UTI were advanced age, male sex, urological abnormality, domicile outside Sherbrooke, living in a nursing home (AOR 11.73; 95% CI 3.70 to 37.15), use of fluoroquinolones (AOR 15.24; 95% CI 5.42 to 42.83) or aminoglycosides (AOR 6.59; 95% CI 1.22 to 35.61) within the previous month, and use of fluoroquinolones during the preceding one to 12 months (AOR 2.45; 95% CI 1.06 to 5.62). Compared with controls, cases were more likely not to receive an active antibiotic as empirical or definitive treatment, and were more likely to relapse.

INTERPRETATION

In the future, it may become necessary to avoid selecting as empirical therapy of urinary tract infection an antibiotic to which the patient has been recently exposed.     

老年人复发性尿路感染长疗程治疗疗效观察

目的 设计一种药物轮换、分期、长疗程的治疗方法,以临床治愈为目标,观察该方法对老年复发性尿路感染患者的疗效.方法 将入选患者分为老年组(年龄≥65岁)30例和非老年组48例,选择数种有效抗生素轮换应用.采用分期治疗方法:(1)治疗期:抗生素按常规剂量应用,直至尿常规正常;(2)巩固期:抗生素减量应用;(3)维持期:抗生素减为每晚1次,维持治疗3个月;(4)观察期:停用抗生素,观察半年.上述各分期如尿常规检查有反复,则转为前一期治疗.结果 78例患者中,治愈69例(88.5%),有效7例(8.9%),无效2例(2.6%).老年组分别为28例、1例、1例;非老年组分别为41例、6例、1例,两组治愈率差异无统计学意义(F=0.469,).老年组与非老年组比较,治愈总疗程[(54.8±16.2)周对(44.5±13.7)周,t=2.8467,P＜0.01]、治疗期[(34.3±15.2)周对(26.2±14.8)局,t=2.2081,P＜0.05]、巩固期[(5.7±2.6)周对(4.1±0.2)周,t=3.9369,P＜0.01]均延长;但两组维持期[(14.8±4.6)周对(14.2±3.1)周]比较,差异无统计学意义(t=0.6480,P＞0.05).治疗前后两组血常规、肝肾功能均无明显变化.结论 对老年复发性尿路感染患者采用药物轮换、分期、长疗程治疗,治愈率高;但老年组所需治疗时间比非老年组长.未见影响血常规、肝肾功能等不良反应.

Abstract：

Objective To observe the therapeutic effects of the drugs alternation multiple stages and long term therapy in elderly patients with recurrent urinary tract infection.Methods The patients were divided into elderly group (age≥65 years,n=30) and non-elderly group (n=48).The multiple effective antibiotics were selected for alternate use.The treatment included four periods as follows:(1)Treatment period:the regular dose of antibiotic was maintained until the urine routine test result became normal;(2)Consolidation period:the dosage of antibiotic was reduced;(3)Maintenance period:the dosage of antibiotic was reduced to once every night and the treatment should be kept for three months;(4)Observation period:the patients were observed for six months after withdrawal of antibiotics.During the treatment,if the urine routine test became abnormal repeatedly,the patient should return to the previous treatment period.During the treatment and consolidation period,each medication should be applied for one week alternatively.Results Among 78 patients,69 cases (88.5%) were cured,7 cases (8.9%) were effective,and two cases (2.56%) were invalid.There were 28 cured cases,1 effective case and 1 invalid case in elderly group.The corresponding data were 41,6 and 1 in non-elderly group,respectively.There was no difference in cure rate between the two groups (F= 0.469).Compared with non-elderly group,the overall treatment time [(54.8± 16.2)weeks vs.(44.5± 13.7) weeks,t= 2.8467,P＜0.01],treatment period [( 34.3± 15.2) weeks vs.(26.2±14.8) weeks,t=2.2081,P＜0.05] and consolidation period [(5.7±2.6) weeks vs.(4.1±0.2) weeks,t=3.9369,P＜0.01] were all prolonged in elderly group.But there was no difference in maintenance period [(14.8±4.6) weeks vs.(14.2±3.1) weeks,t=0.6480,P＞0.05].There were no markedly changes in blood routine,liver and kidney function during the course of treatment.Conclusions For the elderly patients with recurrent urinary tract infection,the drugs alternation,multiple stages and long-term treatment has a high cure rate and no adverse effect on blood routine,liver and renal function.     

血清降钙素原、C反应蛋白对尿路感染的诊断价值

目的探讨血清降钙素原(PCT)、C反应蛋白(CRP)对尿路感染的诊断价值。方法选择上尿路感染患者42例、下尿路感染患者39例,另选取无尿路感染症状的健康查体者45例作为对照组。分别观察各组血清PCT、CRP水平,同时计数血液及尿液中的白细胞。根据培养鉴定结果将上尿路感染组、下尿路感染组再次分为革兰阳性菌感染组、革兰阴性菌感染组和真菌感染组,并对上述指标进行比较。结果上、下尿路感染组血清PCT、CRP及血、尿液WBC明显高于对照组(P均<0.05)。在上、下尿路感染中PCT为0.05 ng/mL时,对尿路感染检测的敏感性为89.7%,特异性为79.6%;CRP为5 mg/L时,敏感性、特异性分别为79.3%、64.3%。革兰阳性菌感染组、革兰阴性菌感染组和真菌感染组4项指标比较差异均无统计学意义。结论血清PCT、CRP可作为诊断尿路感染的有效指标,但PCT更敏感,并可用于辅助鉴别尿路感染部位。     

Molecular comparison of extraintestinal Escherichia coli isolates of the same electrophoretic lineages from humans and domestic animals

Molecular typing methods were used to characterize 38 Escherichia coli strains that originally were isolated from extraintestinal infections and represented 5 multilocus enzyme electrophoretic types (ETs) recovered from both humans and animals. Within each ET, the human and animal isolates did not consistently segregate by host group, according to individual virulence factors (VFs), composite VF-serotype profiles, or pulsed-field gel electrophoresis profiles. Several close matches with respect to VF-serotype profiles were identified between human and canine isolates from different locales. One canine and 2 human isolates of serogroup O6 closely resembled archetypal human pyelonephritis isolate 536 (O6:K15:H31), according to papA sequence and VF-serotype profile. These findings support the hypothesis that certain pathogenic lineages of E. coli cause disease in both humans and animals and that humans may acquire pathogenic E. coli from domestic pets.     

82例重症肺结核合并下呼吸道感染致病菌种的临床分析

目的探讨重症肺结核患者下呼吸道致病菌种分布特点,细菌耐药情况.方法选82例经纤支镜双套管保护性毛刷（PSB）培养发现致病菌株的重症肺结核患者,确定菌种后进行抗菌药物体外药敏检测.结果 82例患者PSB培养发现致病菌株98例次.其中革兰阴性杆菌55株（56.1%）,革兰阳性球菌20株（20.4%）,真菌23株（23.5%）.结论重症肺结核患者呼吸道致病菌种以革兰阴性杆菌居多,但真菌感染亦明显增多,可能与患者免疫功能低下,长期滥用抗生素及不合理应用抗结核药物有关.     

82例重症肺结核合并下呼吸道感染致病菌种的临床分析

目的　探讨重症肺结核患者下呼吸道致病菌种分布特点,细菌耐药情况。方法 选82例经纤支镜双套管保护性毛刷(PSB)培养发现致病菌株的重症肺结核患者,确定菌种后进行抗菌药物体外药敏检测。结果 82例患者PSB培养发现致病菌株98例次。其中革兰阴性杆菌55株(56.1%),革兰阳性球菌20株(20.4%),真菌23株(23.5%)。结论 重症肺结核患者呼吸道致病菌种以革兰阴性杆菌居多,但真菌感染亦明显增多,可能与患者免疫功能低下,长期滥用抗生素及不合理应用抗结核药物有关。     

Sexual Intercourse and Risk of Symptomatic Urinary Tract Infection in Post-Menopausal Women

Background Sexual intercourse increases the risk of symptomatic urinary tract infections (UTI) in young women, but its role among post-menopausal women is unclear. Objective To determine whether recent sexual intercourse, as documented by daily diaries, is associated with an increased risk of symptomatic UTI in post-menopausal women. Design A 2-year prospective cohort study conducted from 1998 to 2002. Participants One thousand and seventeen randomly selected post-menopausal women enrolled at Group Health Cooperative (GHC), a Washington State HMO. Measurements and Main Results Women were asked to enter daily diary information on vaginal intercourse, medication use, and genito-urinary symptoms. The outcome of interest, symptomatic UTI, was defined as a positive urine culture ≥10⁵ CFU/mL of a uropathogen and the presence of ≥2 acute urinary symptoms. Nine hundred thirteen women returned diaries and were included in this study. Seventy-eight women experienced 108 symptomatic UTIs, and 361 (40%) reported sexual intercourse in their diaries. There was an increased hazard for UTI 2 calendar days after the reporting of sexual intercourse in the diaries (adjusted hazard ratio [HR], 3.42, 95% CI 1.49–7.80), while there was no evidence for an increased hazard associated with intercourse at other times. When the UTI criterion was relaxed from ≥10⁵ CFU/mL to ≥10⁴ CFU/mL, adding 9 UTI events to the analysis, the HR for UTI 2 days after intercourse changed slightly to 3.26 (95% CI 1.43–7.43). Conclusions Our data suggest that, as with younger women, recent sexual intercourse is strongly associated with incident UTI in generally healthy post-menopausal women.     

急性脑梗死住院患者医院感染的特征及危险因素分析

目的探讨急性脑梗死住院患者医院感染的特征及危险因素。方法回顾性分析122例急性脑梗死住院患者的临床资料,其中感染组33例和非感染组89例,比较2组感染时间、部位、病原菌及病死率。结果感染组平均感染发生在住院后(3.7±1.6)d,感染部位以下呼吸道最多(63.6%),上呼吸道感染6例(18.2%),泌尿系统感染7例(21.2%)。感染组年龄、吞咽困难、意识障碍、留置胃管、留置导尿、美国国立卫生研究院卒中量表(NIHSS)评分、血浆N末端脑钠肽前体、大面积脑梗死比例明显高于非感染组。其中意识障碍和NIHSS评分是急性脑梗死患者医院感染独立的预测危险因素(P<0.05,P<0.01)。急性脑梗死住院患者死亡23例,占18.9%,其中感染组死亡18例。剔除死亡因素后,感染组平均住院天数明显多于非感染组[(17.8±4.1)d vs(12.5±5.3)d,P<0.01]。结论急性脑梗死住院患者医院感染发生率高,应充分重视这些影响因素,减少医院感染的发生率。     

呼吸科院内尿路感染患者病原菌及耐药分析

目的分析呼吸科院内尿路感染患者的病原菌种类分布及其耐药性,为合理用药提供参考。方法回顾性分析呼吸科明确诊断的院内尿路感染患者35例,分析其尿培养病原菌结果。结果 35例患者共分离出58株病原菌,其中革兰阴性菌27株,占46.55%,革兰阳性菌10株,占17.24%,真菌21株,占36.21%。病原菌按检测率排序前3位依次是大肠埃希菌(18.97%)、白色念珠菌(17.24%)、肺炎克雷伯杆菌(10.34%),药物敏感试验显示:革兰阴性菌及革兰阳性菌耐药性严重。结论呼吸科院内尿路感染病原菌以革兰阴性菌为主,且呈多重耐药现象。真菌感染检出率明显增高,临床需加以重视。