Risk factors for community-onset urinary tract infections due to Escherichia coli harbouring extended-spectrum beta-lactamases

OBJECTIVES: Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli have been increasingly recognized in the community. The aim of this study was to determine the prevalence, types of ESBLs and risk factors for community-onset ESBL-producing E. coli in urinary tract infections (UTIs). METHODS: Adults with community-onset UTIs due to ESBL-producing E. coli (cases) and non-ESBL-producing E. coli (controls) were identified through records of the clinical microbiology laboratory of the hospital. Two different periods were studied: from January 2000 to January 2001 and from October to December 2003. Controls were matched in a 3:1 ratio to case patients according to age, sex, date of isolation and residence in a long-term care facility. Potential risk factors were recorded. Isoelectric focusing as well as PCR and DNA sequencing were used to characterize the bla(TEM), bla(SHV) and bla(CTX-M) genes. A possible clonal relationship among the strains was determined by repetitive extragenic palindromic sequence PCR. RESULTS: The prevalence of infection due to ESBL-producing E. coli increased from 0.47% in 2000 to 1.7% in 2003 (P < 0.001). Community-onset ESBL-producing E. coli infection shifted from 50% in the first period to 79.5% in 2003 (P < 0.001). Nineteen cases and 55 matched controls of community-onset ESBL-producing E. coli UTI were included. ESBL-producing E. coli strains were clonally unrelated. On univariate analysis, genitourinary pathology (P < 0.03), previous bacterial infection (P = 0.01), intravenous antibiotic treatment (P = 0.01), hospitalization in the previous 12 months (P = 0.04) and previous exposure to oral second-generation cephalosporins (P < 0.05) were associated with community-onset infection due to ESBL-producing E. coli. In our regression model, only previous exposure to second-generation cephalosporins was strongly associated with E. coli harbouring ESBLs (OR, 21.42; CI 95%, 5.38-85.22; P < 0.05). In the first period, only TEM- and SHV-derived ESBLs were identified. The enzymes were characterized as members of the TEM group (60%), SHV group (16%) and CTX-M group (24%). CONCLUSIONS: We detected a marked increase in infections due to ESBL-producing E. coli, especially in the community, in the periods studied. Only previous exposure to the oxyimino cephalosporin cefuroxime, and not to ciprofloxacin, aminoglycosides or third-generation cephalosporins, was predictive of an ESBL-producing E. coli community-onset infection in our area. The emergence of the CTX-M type of beta-lactamase in E. coli follows closely the spread of ESBLs in community isolates.     

Molecular epidemiology of multiresistant Escherichia coli isolates from community-onset urinary tract infections in Cornwall, England

OBJECTIVES: To study the clonality of gentamicin-resistant, extended-spectrum beta-lactamase (ESBL)-negative and ESBL-producing Escherichia coli isolated from community-onset urinary tract infections (UTIs) in Cornwall. METHODS: Isolates were identified by API, susceptibilities were determined by local disc testing, and MICs were determined at the reference laboratory, both interpreted using BSAC guidelines. bla(CTX-M) genes were sought by PCR, and isolates were compared by PFGE. RESULTS: In the years 2004 and 2005, 69 E. coli were submitted by Truro (Cornwall) laboratory for reference laboratory testing: these included 14 gentamicin-resistant, ESBL-negative isolates; 45 with group 1 CTX-M enzymes; seven with group 9 CTX-M enzymes; and three with non-CTX-M ESBLs. By PFGE, nine gentamicin-resistant, ESBL-negative E. coli were distinct (<85% similarity) from all the ESBL producers, but three were related to producers of group 1 CTX-M enzymes, and two isolates were related to a non-CTX-M ESBL producer. An outbreak strain was identified, represented by 11 gentamicin-resistant and one gentamicin-susceptible isolates, all with group 1 CTX-M enzymes, and two gentamicin-resistant, ESBL-negative isolates. This was distinct by PFGE from nationally distributed CTX-M-producing strains. Five of nine patients infected with this strain had been on the same ward in a local hospital; four presented with community-onset UTIs; one inpatient developed a hospital-acquired bacteraemia. Of the other four patients presenting with community-onset UTIs, three were admitted to different hospitals and the fourth had only attended an outpatient clinic. CONCLUSIONS: Community-onset, ESBL-producing and non-producing E. coli were diverse. Two ESBL-negative isolates were closely related to a local CTX-M-producing outbreak strain, suggesting gain or loss of a bla(CTX-M)-carrying plasmid. An outbreak strain was linked with prior hospital admission and appeared not to represent genuine community acquisition.     

Clinical features and risk factors of mortality for bacteremia due to community-onset healthcare-associated methicillin-resistant S. aureus

Studies comparing adult community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) and community-onset healthcare-associated MRSA (COHCA MRSA bacteremia have not been available. From 1 January 2010 through 30 October 2010, a prospective observational program was conducted among all patients aged >16 years with positive Staphylococcus aureus blood cultures within 48 h after their arrival at the emergency department of our hospital. Clinical course of infection and infection foci of bacteremia were evaluated. Resistance to oxacillin was confirmed with the presence of mecA gene examined by polymerase chain reaction. Presence of TSST-1, PVL gene, SCCmec elements (I–V), mecA gene, and multilocus sequence typing were identified through methods described elsewhere. Univariate and multivariate analysis revealed that chronic renal failure was significantly more common in COHCA-MRSA than in CA-MRSA. In addition, APACHE III score was significantly higher in COHCA-MRSA than in CA-MRSA. Both the 7-day and 30-day mortality rates in COHCA-MRSA, 14.6% (7/48) and 29.2% (14/48), respectively, were higher than those in CA-MRSA without a significant difference. SCCmec II was more common in COHCA-MRSA, but SCCmecV_T was more common in CA-MRSA. The majority of MRSA isolates belonged to ST59, ST239, and ST5. ST59 was significantly more common in CA-MRSA, while ST239 was nearly equally common in both CA-MRSA and COHCA-MRSA. SCCmec III and II isolates were the first and second most resistant to the antibiotics commonly used for S. aureus, whereas SCCmecV_T isolates were the most susceptible to these antibiotics. We conclude that, although both CA-MRSA and COHCA-MRSA bacteremia had community onset, these 2 MRSA infections were different in underlying diseases, risk of mortality, SCCmec types, sequence types, and antimicrobial susceptibility. It is more appropriate to understand the MRSA pathogen and clinical features based on etiology and ST types than based on the location of disease onset. CA-MRSA and HCA-MRSA should be differentiated also based on etiology and ST types, in addition to location of acquisition.     

Seasonality in Gram-negative and healthcare-associated infections

Clin Microbiol Infect 2012; 18: E934-E940 ABSTRACT: To assess seasonal variations in Gram-negative and healthcare-associated infections (HCAIs), a literature search was performed with combinations of the keywords 'seasonality', 'seasonal variations', 'Gram-negative bacilli', 'infections', 'nosocomial infections', and 'health care associated infections', to retrieve articles published in English in peer-reviewed journals from 1 January 1970 to 29 February 2012. Seasonality was demonstrated for infections, mostly bloodstream infections (BSIs), caused by Acinetobacter spp., Escherichia coli, Enterobacter cloacae, Klebsiella spp., and Pseudomonas aeruginosa, with higher rates of infection during the summer months in North America, Europe, the Middle East, Australia, and Asia. Correlations were observed between temperature increase and rates of BSI for Acinetobacter spp., P.?aeruginosa, E.?coli, Klebsiella pneumoniae, and extended-spectrum β-lactamase-producing Enterobacteriaceae. A significant correlation between lower urinary tract infections and higher temperature and decreased relative humidity could explain the seasonality of some BSIs. Regarding HCAI, seasonality is intrinsically present in most viral respiratory and gastrointestinal infections, because viruses are introduced into hospitals during seasonal community outbreaks. Other HCAIs subject to seasonal variations include surgical wound infections, with winter peaks in the USA and summer peaks in Finland, central-line-associated BSIs in haematology/oncology paediatric outpatients, and dialysis-associated peritonitis. In summary, seasonal variations have been shown for infections caused by many Gram-negative bacilli, as well as for a few HCAIs, but many studies remain to be performed in order to better understand the mechanisms of these variations.     

Controlling healthcare-associated infections in the NHS

The prevention and control of healthcare-associated infection (HCAI) is a priority for the NHS. The delivery of national targets for reducing methicillin resistant Staphylococcus aureus bacteraemias and Clostridium difficile infection are supported by enhanced mandatory surveillance through the Health Protection Agency and a Department of Health improvement programme that promotes policies and protocols for enhancing clinical procedures and places infection prevention and control at the centre of clinical and corporate governance. The Health Act 2006 Code of Practice makes such policies and protocols a legal requirement and compliance will be assessed by the Healthcare Commission. Clinicians must recognise their responsibilities for patient safety and take a lead role in ensuring good practice to reduce HCAI.     

Susceptibility of Danish Escherichia coli strains isolated from urinary tract infections and bacteraemia,and distribution of sul genes conferring sulphonamide resistance

Antibiotic resistance of urinary tract pathogens has increased worldwide. Our aim was to provide information regarding resistance patterns of Escherichia coli in urinary tract infections (UTIs) and E. coli bacteraemia in Denmark. The overall resistance ranged from: ampicillin 20-47%, mecillinam 0-7%, trimethoprim 10-28%, sulfamethizole 22-47% and nitrofurantoin 0-3%. In strains with sulfamethizole MICs > 2048 mg/L, 97% carried sulI, sulII or both genes, with sulII being the most common. Among the sulI gene-positive strains, 96% were intI 1 gene positive.     

Prevention and treatment of enterohemorrhagic Escherichia coli infections in humans

Infections with enterohemorrhagic Escherichia coli (EHEC) result in various clinical symptoms and outcomes ranging from watery or bloody diarrhea to the life-threatening hemolytic-uremic syndrome (HUS). Shiga toxins (Stxs) are supposed to play a major role in the pathogenesis of EHEC infections; however, the role of other putative virulence factors is not fully elucidated. So far, there is only supportive therapy available for the treatment of both EHEC-associated diarrhea and HUS. Antibiotic therapy for the treatment of EHEC-associated diarrhea is discussed. In recent years other therapeutic strategies have been developed, including Gb3 receptor analogues, that bind Stx in the gut or in the circulation, passive immunization with Stx-neutralizing monoclonal antibodies, or active immunization with Stx1 And Stx2 toxoids as a preventive procedure. These approaches have been demonstrated to be effective in animal models but clinical trials are lacking.     

Therapeutic strategies for Shiga toxin-producing Escherichia coli infections

Shiga toxin (Verocytotoxin)-producing Escherichia coli (STEC or VTEC) causes serious gastrointestinal infections in humans, including diarrhea and hemorrhagic colitis, and may lead to life-threatening sequelae such as the hemolytic uremic syndrome (HUS). The triennial ‘VTEC’ meetings provide a multidisciplinary forum for presentation of the latest research on all aspects of STEC, with sessions addressing epidemiology of human disease, animal reservoirs and transmission of STEC via the food chain, mechanisms of pathogenesis and host response, and control and prevention strategies. Management of patients with STEC disease can be challenging, particularly since conventional antibiotic therapy is contraindicated because it is believed to increase the risk of complications by promoting release of Shiga toxin by STEC in the gut. Accordingly, this report will focus on papers presented at the meeting that addressed development of alternative therapeutic strategies.     

Clinical features of Escherichia coli pneumonia

Escherichia coli pneumonia was clinically reviewed. Twenty-two patients with E. coli pneumonia were admitted for treatment to Kawasaki Medical School Kawasaki Hospital, between January 2006 and December 2008. Clinical features were retrospectively reviewed. Results showed that: (1) hospital-acquired pneumonia occurred in elderly patients with underlying diseases, such as cerebrovascular disease, diabetes mellitus, or chronic obstructive pulmonary disease; (2) more patients had complications of urinary-tract infection or alimentary infection due to E. coli; (3) previous administration of antibacterial agents did not become a risk factor; (4) resistance to ampicillin (ABPC) and levofloxacin (LVFX) was observed; and (5) mortality was 22.7%.     

某中医医院大肠埃希菌血流感染临床特征及耐药性分析

摘要 目的 分析某中医医院大肠埃希菌血流感染的易感因素、临床特点及细菌耐药性。方法 回顾性调查该院3年间从血培养中分离出大肠埃希菌的132例患者的临床资料,分析其性别、年龄、科室分布、基础疾病、临床特征、抗生素耐药等情况。结果 大肠埃希菌血流感染以ICU患者发生率最高（48例,36.36%）;最常见首发症状为发热,占91.67%（121例）;93.18%的患者患有各类基础性疾病;产超广谱β内酰胺酶（ESBLs）43株（32.58%）,耐碳氢酶烯类2例（1.52%）,其他抗菌药物耐药率为11.62%～100%。结论 年龄>40岁、有基础性疾病、ICU患者和侵袭性操作是大肠埃希菌血流感染的易患因素,产ESBLs菌株耐药性较高。应做好产ESBLs的检测及常用抗菌药物的药敏试验,指导临床合理用药。     

卫生保健相关性肺炎的临床分析

目的探讨卫生保健相关性肺炎(HCAP)在青岛市市立医院的发病情况,了解其临床特征及病原学特点以指导临床治疗。方法按照CURB-65评分系统将2009年1月—2010年5月住院治疗的91例HCAP患者分为轻症组84例和重症组7例,回顾性分析总结两组的临床特征及病原学特点。结果重症HCAP患者的平均年龄显著高于轻症组[(83.9±7.1)和(65.1±17.8)岁,P<0.001],其基础疾病合并症显著多于轻症组(100%和76.2%),其临床症状(如发热、咳嗽、气短、意识障碍)的比率显著高于轻症组(P<0.05),相关实验室指标(如白细胞异常、尿素氮升高、低氧血症或低氧和指数)明显重于轻症组(P<0.01)。与轻症组相比,重症HCAP患者多次住院、接受家庭或医疗机构护理者更多(P<0.001)。重症HCAP患者多种细菌混合感染高达71.4%,其中革兰阴性菌占44.5%,革兰阳性菌占22.2%,念珠菌占33.3%,初始抗生素治疗未能覆盖病原菌而治疗不当者4例,死亡3例,与轻症组相比差异均有统计学意义(P<0.01)。结论 HCAP的发生与医疗环境密切相关,其中CURB-65评分高的重症患者基础疾病多,病原菌中多重耐药菌发生率高,预后差。必须充分认识HCAP发病的危险因素和病情严重程度,建立个体化"经验性治疗方案",以改善预后。     

The scope of guidelines to prevent healthcare-associated infections

As care is increasingly delivered in the community rather than acute settings, there has been concern that this might be accompanied by a rise in healthcare-associated infection. Consequently, the National Institute for Clinical Excellence (NICE) has commissioned a set of infection prevention guidelines for healthcare workers in community and primary care. The guideline developers were anxious to concentrate this guidance on the areas of most concern to practitioners, particularly in relation to devices. This article describes how a survey and focus groups were employed to identify the areas for guideline development, namely standard principles, long-term indwelling urinary catheters, enteral feeds and central intravascular devices.     

Effects of vaccination in urinary infections caused by Escherichia coli in rats

The preventive effects of the immunomodulator P40 on the experimental E. coli infection of the lower urinary tract of the rat have been reported previously. In the present paper are presented the results obtained with the aid of vaccination using the same experimental model of infection in the rat. Active specific immunization of the animals with a vaccine consisting of the same strain as that used for infecting the rats afforded significant protection toward the infection. It is concluded that such vaccines could also be used in humans, either alone or in combination with other therapies with the aim at preventing recurrencies or relapses of infections of the lower urinary tract which were resistant to antibiotherapy.