Growth of uropathogenic Escherichia coli strains at solid surfaces

The adhesion and growth of two catheter-associated (O2K2 and O83K?) and two non catheter-associated (O111K58 and 0157K-) uropathogenic Escherichia coli strains on glass, poly(methyl methacrylate) (PMMA), a negatively charged copolymer of MMA and methacrylic acid (MAA) and a positively charged copolymer of MMA and trimethylaminoethyl methacrylate chloride (TMAEMA-Cl) were studied. The solid surfaces were placed in a parallel plate perfusion system. After preadhesion of the bacteria onto the surfaces, growth was initiated by perfusing the system with MacConkey broth. Growth was measured by counting adherent bacteria as a function of time. Bacterial strains were characterized by means of water contact angle, microbial adhesion to hydrocarbon (MATH), anion exchange resin retention (ARR) and zeta potential measurements. Solid surfaces were characterized by means of water contact angle and zeta potential measurements. The catheter-associated strains had significantly higher water contact angles, zeta potentials and ARR values than the non catheter-associated strains. Non catheter-associated strains did not grow at the surfaces used. Catheter-associated strains did not grow at the positively charged surface but exhibited growth at the other surfaces. Strains grew more rapidly at surfaces with a relatively high negative zeta potential and a low water contact angle than at surfaces with a relatively low negative zeta potential and a high water contact angle. The growth of strain O2K2 on glass was significantly reduced when urine instead of MacConkey broth was used as perfusion medium.     

TEMPO-NaBr-NaClO 体系对细菌纤维素的氧化过程研究

细菌纤维素是具有天然纳米网状结构的支架材料,选择性催化氧化可改善其降解性能。以NaClO、TEMPO和反应时间为变量,研究2,2,6,6-四甲基哌啶-1-氧化物自由基(TEMPO)/NaBr/NaClO体系对细菌纤维素的氧化。结果表明,在试验条件范围内,体系初始阶段的反应速率随NaClO用量的增加而减小;体系pH值是影响此阶段反应速率的主要因素且体系最大反应速率出现在pH＝10.50～11.00之间;TEMPO用量对此阶段反应速率的影响不明显。对整个反应过程而言,体系的反应速率和不溶性产物的羧基含量都随NaClO用量的增加而增大,其中NaClO用量在1～8 mL之间时,都呈现良好的线性关系;二者都随催化剂TEMPO用量的增加而增大。不溶性产物的羧基含量随反应时间的延长先逐渐减小后保持相对稳定在0.70～0.75 mol/kg。在不同反应阶段,TEMPO/NaBr/NaClO体系对BC的氧化规律存在明显差异,BC独特的结构特点可能是导致这种差异的主要原因。     

自体微小颗粒骨植骨混合万古霉素开放性植骨修复感染性胫骨缺损

背景：研究发现直径300-500 μm微米结构的微小颗粒骨比直径4.0-5.0 mm的经典颗粒骨更容易在非感染骨缺损中成活。 目的：评价采用自体微小颗粒骨植骨混合万古霉素开放性植骨修复感染性胫骨骨缺损的可行性及临床效果。 方法：选择28例胫骨感染性骨缺损或骨不连患者,其中男23例,女5例,平均年龄35.2岁;胫骨上段19例,胫骨中段2例,胫骨下段7例;开放性骨折术后感染病例17例,骨折术后感染合并骨不连11例。随访6-30个月观察创面及骨折愈合情况。 结果与结论：术后平均6周移植微小颗粒骨表面被肉芽组织覆盖,平均8周创面完全闭合,经植骨后骨缺损处均骨性愈合,2例骨折愈合差,经二次植骨后达到骨性愈合,平均愈合时间5个月。未发生神经血管损伤及药敏反应。表明自体微小颗粒骨植骨混合万古霉素开放性植骨修复治疗感染性胫骨缺损是可行的。     

Novel point-of-care biomarker combination tests to differentiate acute bacterial from viral respiratory tract infections to guide antibiotic prescribing: a systematic review

BackgroundAcute respiratory tract infections (RTIs) are the most common reason to seek medical care, with many patients receiving inappropriate antibiotics. Novel testing approaches to identify aetiology at the point-of-care are required to accurately guide antibiotic treatment.ObjectiveTo assess the diagnostic accuracy of biomarker combinations to rapidly differentiate between acute bacterial or viral RTI aetiology.Data sourcesMEDLINE, Embase and Web of Science databases were searched to February 2021.Study eligibility criteriaDiagnostic accuracy studies comparing accuracy of point-of-care and rapid diagnostic tests in primary or secondary care, consisting of biomarker combinations, to identify bacterial or viral aetiology of RTI.MethodsRisk of bias was assessed using the QUADAS-2 tool. Sensitivity and specificity of tests reported by more than one study were meta-analysed using a random effects model.ResultsTwenty observational studies (3514 patients) were identified. Eighteen were judged at high risk of bias. For bacterial aetiologies, sensitivity ranged from 61% to 100% and specificity from 18% to 96%. For viral aetiologies, sensitivity ranged from 59% to 97% and specificity from 74% to 100%. Studies evaluating two commercial tests were meta-analysed. For ImmunoXpert, the summary sensitivity and specificity were 85% (95% CI 75%–91%, k = 4) and 86% (95% CI 73%–93%, k = 4) for bacterial infections, and 90% (95% CI 79%–96%, k = 3) and 92% (95% CI 83%–96%, k = 3) for viral infections, respectively. FebriDx had pooled sensitivity and specificity of 84% (95% CI 75%–90%, k = 4) and 93% (95% CI 90%–95%, k = 4) for bacterial infections, and 87% (95% CI 72%–95%; k = 4) and 82% (95% CI 66%–86%, k = 4) for viral infections, respectively.ConclusionCombinations of biomarkers show potential clinical utility in discriminating the aetiology of RTIs. However, the limitations in the evidence base, due to a high proportion of studies with high risk of bias, preclude firm conclusions. Future research should be in primary care and evaluate patient outcomes and cost-effectiveness with experimental study designs.Clinical trialPROSPERO registration number: CRD42020178973.     

High prevalence of anti-HEV antibodies among patients with immunosuppression and hepatic disorders in eastern Poland

IntroductionThe incidence of hepatitis E virus (HEV) infections in Poland is largely unknown. This study aimed to describe seroprevalence of markers of HEV infection among patients with immunodeficiency of diverse etiology and patients with advanced chronic liver diseases.Material and methodsFour hundred fifty patients were enrolled; among them, 180 persons were solid organ transplant recipients, 90 patients were HIV-infected and 180 persons had confirmed liver cirrhosis of different etiology. Serum anti-HEV-IgG, IgM antibodies and HEV-antigen were detected by ELISA (Wantai, China).ResultsIn the group of transplant recipients, serum anti-HEV-IgG antibodies were detected in 40.6%, IgM in 1.1% and HEV-Ag in 2.8% of subjects. In the HIV-infected population 37.7% had anti-HEV-IgG, 1.1% had anti-HEV-IgM and none had HEV-Ag. Among patients with advanced chronic liver diseases the highest prevalence of anti-HEV-IgG was recorded in alcohol-related liver cirrhosis (52.1%) (p = 0.049). In the population of all liver cirrhotics anti-HEV-IgG seroprevalence was 48.3%, anti-HEV-IgM seroprevalence was 5.0% and HEV-Ag seroprevalence was 1.7%. Older age and male gender were significant risk factors associated with increased anti-HEV-IgG prevalence, p = 0.0004 and p = 0.02, respectively.ConclusionsIn this large cohort a high seroprevalence of anti-HEV-IgG was detected in comparison to other European countries, with the highest rates in patients with alcoholic liver disease and in transplant recipients.     

Phenotypic and genotypic detection of extended spectrum β-lactamases among Escherichia coli and Klebsiella pneumoniae isolates from type 2 diabetic patients with urinary tract infections

BackgroundT2DM patients are more likely to have UTIs caused by resistant organisms such as ESBLs producing bacteria. Challenging reliable identification and prompt characterization of in-vitro susceptibilities of these bacteria are the first steps of deciding the appropriate antimicrobial therapy for UTIs caused by them.ObjectivesTo isolate and identify E. coli and K. pneumoniae from urine of T2DM patients with UTIs, to determine antibiotic resistance pattern among isolates, and to identify ESBLs production phenotypically and genotypically.Material and methodAll samples were cultured on Cystine-Lactose-Electrolyte-Deficient Agar medium (CLED) by using calibrated loop. Growth of 100 colonies or more, i.e. 105 colony forming units (CFU)/mL urine was considered as significant bacteriuria. Isolation and identification were done according to standard method. All isolates were tested for antibiotic susceptibility testing by the disc diffusion method according to CLSI guidelines. Phenotypic detection of ESBLs was done by double-disk synergy test. Genotypic detection of blaTEM, blaSHV and blaCTX-M genes by using PCR.ResultsResults of this study showed that E. coli and K. pneumoniae were the dominant bacterial isolates, they constituted 103 (91.2%) out of 113 urine isolates. E. coli (58. 4%) K. pneumoniae (32.7%), Enterococcus spp. (4.4%), Proteus spp. (2.7%) and Pseudomonas spp. (1.8%). About 25 (24.3%) out of 103 E. coli and K. pneumoniae isolates were ESBLs positive by DDST, and 22 (88.0%) out of them had ESBLs encoding genes by conventional PCR. The most common gene detected was blaTEM (59.1%), followed by blaSHV (27.3%). CTX-M had not been detected in any of testes isolates.ConclusionblaTEM and blaSHV genes were detected in 22 out of 25 ESBLs producing E. coli and K. pneumoniae isolates phenotypically detected by DDST. blaTEM was found to be the predominant gene (59.1%), while blaCTX-Mene was not detected in any of tested isolates.     

A systemic review of barriers to accessing paediatric eye care services in African countries

BackgroundGlobal estimate reported that 1.4 million children are blind of which three-quarters live in developing countries. Childhood Visual Impairment is a major public health problem globally especially in rural areas of developing countries.ObjectiveTo review barriers to accessing paediatric eye care services in African countriesMethodsThe studies in this review were searched in online databases (PubMed, Web of Sciences, ProQuest, Scopus, Google Scholar, African Index Medicus and Medline) for studies published between January 2000 and April 2020. The articles included in this review, which was conducted in Africa to assess the barriers for accessing paediatric eye care services with regards availability, accessibility, affordability, socio cultural barriers of parents/caregivers and community.ResultsOf 22 705 articles screened, the study found 29 publications from 10 African countries which met the inclusion criteria. The main barriers were non-availability, non-accessibility, and non-affordability of paediatric eye care services. The studies reviewed revealed that there are other factors affecting the utilization of paediatric eye services which include the primary health system, geographic barriers, health beliefs, perception of parents; lack of knowledge, attitudes and practices about paediatric eye care. Furthermore, environmental, demographic barriers and socio-economic status has negative impact on accessing paediatric eye care services in African counties.ConclusionThe main barriers to accessing paediatric eye care services in Africa were affordability, accessibility and availability. There is therefore a need for all relevant stakeholders to play a significant role in addressing barriers to child eye care in African countries.     

Episomal and stable expression of the luciferase reporter gene for quantifying Leishmania spp. infections in macrophages and in animal models

We have expressed the reporter firefly luciferase gene (LUC) in Leishmania donovani and Leishmania major either as part of episomal vectors or integrated into the parasite genome under the control of their respective ribosomal promoter regions. An excellent linear correlation between parasite number and luciferase activity was observed with all the transfectants. LUC-expressing recombinant parasites were useful to monitor Leishmania spp. infections in macrophages or in animal models. For prolonged growth in absence of drug selection, such as within animal models, quantitation of parasites is more reliable when the reporter gene LUC is stably integrated in the parasite genome. These recombinant strains should be useful tools to monitor Leishmania growth under a number of conditions.     

Comparison of assays to detect cytomegalovirus shedding in the semen of HIV-infected men

We sought to determine the optimal assays for cytomegalovirus (CMV) shedding in semen. Over a 2-month period, 149 HIV-1-infected men who have sex with men each provided up to three semen specimens. Specimens were tested for CMV by culture, rapid assay (shell vial) and polymerase chain reaction (PCR). By culture, 30% of seminal plasma and 28% of seminal cell specimens grew CMV. By rapid assay, results were 38 and 33%, respectively. By PCR, 56% of seminal cell specimens demonstrated CMV: 20% in a single semen specimen; 33% in two specimens; and 34% in all three specimens. Overall, 69% of men had CMV detected by PCR in at least one seminal cell specimen. By quantitative PCR, 14% had ten, 14% had 100, 16% had 1000, and 12% had 10 000 copies in 6.25 μl of semen analyzed. Adjusting for initial CD4+ cell count, men with CMV shedding demonstrated by PCR at the first visit were approximately four times as likely to shed CMV at a subsequent visit (RR 4.28, CI: 2.30–7.95). CMV shedding was associated with decreased CD4+ cell counts in peripheral blood (P=0.05). It is concluded that the PCR assay provided the greatest sensitivity among the three detection methods.