Alert surveillance of intensive care unit-acquired Acinetobacter infections in a Sicilian hospital

The epidemiological impact of Acinetobacter baumannii nosocomial infections in a Sicilian intensive care unit (ICU) was investigated to determine the Acinetobacter-specific infection rates, to estimate the preventable proportion of Acinetobacter infections, i.e., those resulting from cross-transmission, and to investigate the molecular epidemiology of antimicrobial resistance in Acinetobacter. The impact of Acinetobacter nosocomial infection in the ICU was determined to be 3.0 new cases per 100 admissions. Site-specific rates confirmed that ICU-acquired pneumonia was the most important infection type. The incidence rate, adjusted by the number of patient-days, was 3.3 infections/1000 patient-days. The estimated preventable proportion of A. baumannii nosocomial infections in the ICU was 66.7%. A class 1 integron, characterised by its gene cassette content, was present in all A. baumannii isolates of four different pulsed-field gel electrophoresis types, and was associated significantly with clones implicated in cross-transmission episodes. Furthermore, the same integron was detected in two genetically distinct isolates responsible for recurrent infection in the same patient, suggesting the occurrence of horizontal gene transfer in vivo. Even in an endemic setting with low infection rates, spread of A. baumannii was caused mainly by infection control shortcomings that require appropriate surveillance and control policies.     

New genome type of adenovirus serotype 19 causing nosocomial infections of epidemic keratoconjunctivitis in Japan

Twelve strains of adenovirus serotype 19, isolated from cases of epidemic keratoconjunctivitis in Japan in 1992, 1993, 1997, and 1998, were analyzed by DNA restriction analysis, using restriction endonucleases BamHI, BglI, BglII, EcoRI, HindIII, KpnI, PstI, SacI, SalI, SmaI, and XhoI. Among these 11 restriction endonucleases, EcoRI, PstI, SacI, and SmaI were discriminative enzymes, showing restriction patterns different from those reported previously for the prototype and the variant 19a. This new genome type was isolated in 1997 and 1998, when an increase of epidemic keratoconjunctivitis cases caused by adenovirus serotype 19 was observed for both sporadic and nosocomial infections. Strains from 1992 and 1993 showed restriction patterns similar to those of the worldwide reported variant 19a for all enzymes used. The changes detected in strains from 1997 and 1998 could be the reason for the recent epidemic.     

PCR-based DNA fingerprinting of Staphylococcus haemolyticus to investigate nosocomial infections

Objective: To apply PCR-based DNA fingerprinting in a clinical microbiology laboratory to investigate nosocomial infections with Staphylococcus haemolyticus.
Method: DNA fingerprints were generated by PCR on 99 S. haemolyticus isolates using different primer combinations based on ERIC, REP or arbitrarily chosen simple repeat sequences.
Results: Primer combinations REP1+(GTC)₆ and ERIC1+ERIC2 had sufficient discrimatory power and were chosen to analyze the clinical isolates. DNA fingerprint patterns from strains isolated from the patients nursed in the same hospital ward in the period 1991–94 were approximately 90% similar to each other. One staff member, sampled in 1991, carried a strain with a similar fingerprint.
Conclusions: PCR based DNA fingerprinting is a suitable method to perform in a clinical laboratory. An S. haemolyticus strain appeared to be endemic in the hospital ward and had most probably been transmitted from patient to patient. S. haemolyticus may carry glycopeptide resistance and needs attention as a causative agent of nosocomial infections.     

A European perspective on intravascular catheter-related infections: report on the microbiology workload, aetiology and antimicrobial susceptibility (ESGNI-005 Study)

The laboratory workload, microbiological techniques and aetiology of catheter-related infections in European hospitals are mostly unknown. The present study (ESGNI-005) comprised a 1-day (22 October 2001), laboratory-based, point-prevalence survey based on a questionnaire completed by microbiology laboratories in European (European Union (EU) and non-EU) hospitals. Also included were questions requesting retrospective information for the year 2000. In total, 151 hospitals from 26 European countries participated, of which 78.1% were teaching institutions. Overall, the estimated population served by these institutions was 121,363,800, and the estimated number of admissions during 2000 was 6,712,050. The total number of catheter tips processed during 2000 was 142,727, or 21/1,000 admissions, of which 23.7% were considered to be positive in the institutions using semiquantitative or quantitative techniques. Overall, EU centres received significantly more catheter tip samples/1,000 admissions and had a significantly higher rate of 'positivity' (p < 0.0001) than non-EU centres. Of the institutions surveyed, 11.4% (7.2% in EU countries and 23.7% in non-EU countries; p 0.04) used only qualitative techniques for catheter tip sample processing. On the day of the study, 167 microorganisms were recovered from significant catheter tip cultures (122 patients), of which Gram-positive bacteria represented 70.7%, Gram-negative bacteria 22.2%, and yeasts 7.2%. The five most common microorganisms were coagulase-negative staphylococci, Staphylococcus aureus, Candida spp., Enterococcus spp. and Pseudomonas spp. Overall, 19% of catheter tip cultures were polymicrobial. In the case of S. aureus, 40% of isolates were resistant to oxacillin, as were 63.4% of coagulase-negative staphylococcus isolates. Of 37 Gram-negative isolates, 35% were resistant to cefotaxime, 31% to ceftazidime, and 27% to ciprofloxacin. Imipenem and cefepime had the lowest reported rates of resistance (11%).     

Nosocomial vs. community-acquired infective endocarditis in Greece: changing epidemiological profile and mortality risk

Current epidemiological trends of infective endocarditis (IE) in Greece were investigated via a prospective cohort study of all cases of IE that fulfilled the Duke criteria during 2000-2004 in 14 tertiary and six general hospitals in the metropolitan area of Athens. Demographics, clinical data and outcome were compared for nosocomial IE (NIE) and community-acquired IE (CIE). NIE accounted for 42 (21.5%) and CIE for 153 (78.5%) of 195 cases. Intravenous drug use was associated exclusively with CIE, while co-morbidities (cardiovascular disease, diabetes mellitus, chronic renal failure requiring haemodialysis and malignancies) were more frequent in the NIE group (p <0.05). Prosthetic valve endocarditis (PVE) predominated in the NIE group (p 0.006), and >50% of NIE cases had a history of vascular intervention. Coagulase-negative staphylococci and enterococci were more frequent in cases of NIE than in cases of CIE (26.2% vs. 5.2%, p <0.01, and 30.9% vs. 16.3%, p 0.05, respectively). Enterococci accounted for 19.5% of total IE cases and were the leading cause of NIE. Staphylococcus aureus IE was hospital-acquired in only 11.9% of cases. In-hospital mortality was higher for NIE than for CIE (39.5% vs. 18.6%, p 0.02). Cardiac failure (New York Heart Association grade III-IV; OR 13.3, 95% CI 4.9-36.1, p <0.001) and prosthetic valve endocarditis (OR 3.7, 95% CI 1.3-10.6, p 0.01) were the most important predictors of mortality.     

失效模式与效应分析法在神经内科ICU医院感染控制中的应用

目的探讨失效模式与效应分析法(failure mode and effects analysis,FMEA)在神经内科ICU医院感染控制中的应用,发现高风险因素,为院感防控提供参考依据。方法根据神经内科ICU临床实际情况,通过FMEA风险评估法对34项医院感染风险事件进行风险评估,按照"二八法则"筛选出风险优先级事件。结果根据每一项风险因素的平均RPN值进行风险排序,按照"二八法则"筛选出风险优先级前6位的事件分别是:本科室医护人员手卫生依从性不到位(平均RPN值=5.6)、导尿管日常维护不到位(平均RPN值=4.17)、多耐患者未有效执行接触隔离措施(平均RPN值=3.80)、物表清洁消毒未有效执行(平均RPN值=3.73)、未严格掌握留置导尿指征(平均RPN值=3.70)、未保持尿液引流系统的密闭性(平均RPN值=3.53)。结论FMEA风险评估法可以发现神经内科ICU医院感染防控中的薄弱环节,为精准化感控措施的制订提供依据。     

五年住院病人医院感染率分析

目的 :了解五年中医院感染的动态变化情况 ,为控制医院感染提供依据。方法 :科室自报和专职人员补漏相结合 ,发现医院感染病例 ,调查所有住院病人。结果 :1994年 7月～ 1998年 10月 ,某医院住院病人共计 5 9413例 ,发生医院感染 362 2例次 ,总医院感染率 6 10 % ,1994～ 1998年感染率分别为 8 0 5 %、7 98%、6 16%、4 97%、4 5 1% ,呈持续下降。部位例次感染率以上呼吸道最高 ( 2 67% ) ,手术伤口 ( 1 15 % )次之 ,下呼吸道感染率( 1 0 8% )居第三位 ,但不同年份的不同部位感染率的位次略有变化 ,外科、儿科、内科感染率分别为 9 0 3%、8 0 6%和 6 70 % ,居前三位。但不同年份不同科室所居位次变化较大。结论 :医院感染率的持续下降 ,原因是多方面的 ,但监测工作对感染率的降低所起的作用 ,是不容忽视的。在医院感染控制时应以上一年的监测结果为依据 ,把感染率最高的科室作为重点 ,查找其感染率高的原因 ,并采取相应控制措施 ,降低其医院感染率。这样交替进行 ,最终将能达到降低全院感染率之目的     

监护病室院内获得性败血症—常见致病菌株、危险因素及预后分析

目的：确定监护病室院内获得性败血症的发病率,致病菌的种类,对危重病患者预后的影响及诱发败血症的危险因素。方法：用单因素和多因素统计学方法确定败血症对危重患者预后的影响及诱发败血症的危险因素。结果：败血症在危重患者中有较高的发生率（8．07％）且致病菌以革兰氏阳性球菌为主。病死率亦较高（80．77％）,单因素检验[OR=4.32,95%可信区间（CI）1．58－11．72]及多因素logistic回归分析（OR＝4．97,1.21-20.37)均判定细菌性败血症显著影响危重病患者的病死率,此外,分析亦证实：监护病室血源性感染的发生与患者免疫功能低下,留置大静脉导管,气管切开,低白蛋白血症,感染发生前用过激素等因素密切相关。结论：败血症是监护病室常见并发症且对疾病预后有不利影响,应重视并针对其危险因素加以预防。     

The effect of respiratory activity,non-invasive respiratory support and facemasks on aerosol generation and its relevance to COVID-19

Respirable aerosols (< 5 µm in diameter) present a high risk of SARS-CoV-2 transmission. Guidelines recommend using aerosol precautions during aerosol-generating procedures, and droplet (> 5 µm) precautions at other times. However, emerging evidence indicates respiratory activities may be a more important source of aerosols than clinical procedures such as tracheal intubation. We aimed to measure the size, total number and volume of all human aerosols exhaled during respiratory activities and therapies. We used a novel chamber with an optical particle counter sampling at 100 l.min^-1 to count and size-fractionate close to all exhaled particles (0.5–25 µm). We compared emissions from ten healthy subjects during six respiratory activities (quiet breathing; talking; shouting; forced expiratory manoeuvres; exercise; and coughing) with three respiratory therapies (high-flow nasal oxygen and single or dual circuit non-invasive positive pressure ventilation). Activities were repeated while wearing facemasks. When compared with quiet breathing, exertional respiratory activities increased particle counts 34.6-fold during talking and 370.8-fold during coughing (p < 0.001). High-flow nasal oxygen 60 at l.min^-1 increased particle counts 2.3-fold (p = 0.031) during quiet breathing. Single and dual circuit non-invasive respiratory therapy at 25/10 cm.H₂O with quiet breathing increased counts by 2.6-fold and 7.8-fold, respectively (both p < 0.001). During exertional activities, respiratory therapies and facemasks reduced emissions compared with activities alone. Respiratory activities (including exertional breathing and coughing) which mimic respiratory patterns during illness generate substantially more aerosols than non-invasive respiratory therapies, which conversely can reduce total emissions. We argue the risk of aerosol exposure is underappreciated and warrants widespread, targeted interventions.