Diameter of titanium nanotubes influences anti-bacterial efficacy

Bacterial infection of in-dwelling medical devices is a growing problem that cannot be treated by traditional antibiotics due to the increasing prevalence of antimicrobial resistance and biofilm formation. Here, due to changes in surface parameters, it is proposed that bacterial adhesion can be prevented through nanosurface modifications of the medical device alone. Toward this goal, titanium was created to possess nanotubular surface topographies of highly controlled diameters of 20, 40, 60, or 80 nm, sometimes followed by heat treatment to control chemistry and crystallinity, through a novel anodization process. For the first time it was found that through the control of Ti surface parameters including chemistry, crystallinity, nanotube size, and hydrophilicity, significantly changed responses of both Staphylococcus epidermidis and Staphylococcus aureus (pathogens relevant for orthopaedic and other medical device related infections) were measured. Specifically, heat treatment of 80 nm diameter titanium tubes produced the most robust antimicrobial effect of all surface treatment parameters tested. This study provides the first step toward understanding the surface properties of nano-structured titanium that improve tissue growth (as has been previously observed with nanotubular titanium), while simultaneously reducing infection without the use of pharmaceutical drugs.

What is new in the prevention of ventilator-associated pneumonia?

PURPOSE OF REVIEW

Ventilator-associated pneumonia (VAP) remains a frequent and severe complication in endotracheally intubated patients. Strict adherence to preventive measures reduces the risk of VAP. The objective of this paper is to review what has come forward in recent years in the nonpharmacological prevention of VAP.

RECENT FINDINGS

It seems advantageous to implement care bundles rather than single prevention measures. A solid basis of knowledge seems necessary to facilitate implementation and maintain a high adherence level. Continuous educational efforts have a beneficial effect on attitude toward VAP. Intermittent subglottic secretions drainage, continuous lateral rotation therapy, and polyurethane cuffed endotracheal tubes decrease the risk of pneumonia. In an in-vitro setting, an endotracheal tube with a taper-shaped cuff appears to better prevent fluid leakage compared to cylindrical polyurethane or polyvinylchloride cuffed tubes. Cuff pressure control by means of an automatic device and multimodality chest physiotherapy need further investigation, as do some aspects of oral hygiene.

SUMMARY

New devices and strategies have been developed to prevent VAP. Some of these are promising but need further study. In addition, more attention is being given to factors that might facilitate the implementation process and the challenge of achieving high adherence rates.

Reducing infections through nanotechnology and nanoparticles

The expansion of bacterial antibiotic resistance is a growing problem today. When medical devices are inserted into the body, it becomes especially difficult for the body to clear robustly adherent antibiotic-resistant biofilm infections. In addition, concerns about the spread of bacterial genetic tolerance to antibiotics, such as that found in multiple drug-resistant Staphylococcus aureus (MRSA), have significantly increased of late. As a growing direction in biomaterial design, nanomaterials (materials with at least one dimension less than 100 nm) may potentially prevent bacterial functions that lead to infections. As a first step in this direction, various nanoparticles have been explored for improving bacteria and biofilm penetration, generating reactive oxygen species, and killing bacteria, potentially providing a novel method for fighting infections that is nondrug related. This review article will first examine in detail the mechanisms and applications of some of these nanoparticles, then follow with some recent material designs utilizing nanotechnology that are centered on fighting medical device infections.

Improving hand hygiene compliance rates in the haemodialysis setting: more than just more hand rubs

BACKGROUND

Haemodialysis patients are at high risk for developing healthcare-associated infections as well as acquiring multidrug-resistant microorganisms. Hand hygiene is considered to be the single most effective tool to prevent healthcare-associated infections. The number of indications and the extent of indication-specific compliance with hand rubs in the haemodialysis setting are currently unknown.

METHODS

We conducted a prospective, three-phase, observational intervention study on hand hygiene during haemodialysis treatments. Optimized hand hygiene standard operating procedures (SOPs) for dialysis connections (Intervention I) and disconnections (Intervention II) were compiled and implemented during two predefined intervention periods.

RESULTS

A total of 8897 indications for hand rubs were observed throughout this study. In the course of the study, we identified an increase in the number of hand rubs performed (6-9, mean number per dialysis procedure), parallelled by a decrease in the indications for hand rubs (21-15), resulting in a significant increase of overall hand rub compliance (30-62%). The greatest improvement was seen before aseptic tasks (21-52%), the indication with the greatest impact on preventing healthcare-associated infections. There was no difference between haemodialysis via central venous catheter access or arterio-venous (AV) fistulas.

CONCLUSIONS

This study provides the first detailed data on the number of and indications for hand rubs during dialysis. An >100% increase in overall hand hygiene compliance could be achieved by a comparably moderate increase in hand rubs performed in combination with optimized hand hygiene SOPs.

Device-associated infection rates and extra length of stay in an intensive care unit of a university hospital in Wroclaw, Poland: International Nosocomial Infection Control Consortium's (INICC) findings

PURPOSE

The aim of this study was to determine device-associated health care-associated infections (DA-HAI) rates, microbiologic profile, bacterial resistance, and length of stay in one intensive care unit (ICU) of a hospital member of the International Nosocomial Infection Control Consortium (INICC) in Poland.

MATERIALS AND METHODS

A prospective DA-HAI surveillance study was conducted on an adult ICU from January 2007 to May 2010. Data were collected by implementing the methodology developed by INICC and applying the definitions of DA-HAI provided by the National Healthcare Safety Network at the US Centers for Disease Control and Prevention.

RESULTS

A total of 847 patients hospitalized for 9386 days acquired 206 DA-HAIs, an overall rate of 24.3% (95% confidence interval [CI], 21.5-27.4), and 21.9 (95% CI, 19.0-25.1) DA-HAIs per 1000 ICU-days. Central line-associated bloodstream infection rate was 4.01 (95% CI, 2.8-5.6) per 1000 catheter-days, ventilator-associated pneumonia rate was 18.2 (95% CI, 15.5-21.6) per 1000 ventilator-days, and catheter-associated urinary tract infection rate was 4.8 (95% CI, 3.5-6.5) per 1000 catheter-days. Length of stay was 6.9 days for those patients without DA-HAI, 10.0 days for those with central line-associated bloodstream infection, 15.5 days for those with ventilator-associated pneumonia, and 15.0 for those with catheter-associated urinary tract infection.

CONCLUSIONS

Most DA-HAI rates are lower in Poland than in INICC, but higher than in the National Healthcare Safety Network, expressing the feasibility of lowering infection rates and increasing patient safety.

Modelling the effect of heterogeneity of shedding on the within herd Coxiella burnetii spread and identification of key parameters by sensitivity analysis

Coxiella burnetii is the bacterium responsible for Q fever, a worldwide zoonosis. Ruminants, especially cattle, are recognized as the most important source of human infections. Although a great heterogeneity between shedder cows has been described, no previous studies have determined which features such as shedding route and duration or the quantity of bacteria shed have the strongest impact on the environmental contamination and thus on the zoonotic risk. Our objective was to identify key parameters whose variation highly influences C. burnetii spread within a dairy cattle herd, especially those related to the heterogeneity of shedding. To compare the impact of epidemiological parameters on different dynamical aspects of C. burnetii infection, we performed a sensitivity analysis on an original stochastic model describing the bacterium spread and representing the individual variability of the shedding duration, routes and intensity as well as herd demography. This sensitivity analysis consisted of a principal component analysis followed by an ANOVA. Our findings show that the most influential parameters are the probability distribution governing the levels of shedding, especially in vaginal mucus and faeces, the characteristics of the bacterium in the environment (i.e. its survival and the fraction of bacteria shed reaching the environment), and some physiological parameters related to the intermittency of shedding (transition probability from a non-shedding infected state to a shedding state) or to the transition from one type of shedder to another one (transition probability from a seronegative shedding state to a seropositive shedding state). Our study is crucial for the understanding of the dynamics of C. burnetii infection and optimization of control measures. Indeed, as control measures should impact the parameters influencing the bacterium spread most, our model can now be used to assess the effectiveness of different control strategies of Q fever within dairy cattle herds.

Telavancin: a lipoglycopeptide antimicrobial for the treatment of complicated skin and skin structure infections caused by gram-positive bacteria in adults

BACKGROUND

Telavancin, a lipoglycopeptide antibiotic, is a semisynthetic derivative of vancomycin. It was approved by the US Food and Drug Administration (FDA) in 2009 for the treatment of complicated skin and skin structure infections (cSSSIs) caused by gram-positive bacteria, including methicillin-resistant Staphylococcus aureus.

OBJECTIVE

This article summarizes the pharmacology, in vitro and in vivo activity, pharmacokinetic properties, and clinical efficacy and tolerability of telavancin.

METHODS

Relevant information was identified through a search of MEDLINE (1966-August 2010), Iowa Drug Information Service (1966-August 2010), International Pharmaceutical Abstracts (1970-August 2010), and Google Scholar using the terms telavancin, lipoglycopeptide, and TD-6424. Abstracts and posters from scientific meetings, as well as documents submitted by the manufacturer of telavancin to the FDA as part of the approval process, were consulted. In vivo and in vitro experimental and clinical studies and review articles that provided information on the activity, mechanism of action, pharmacologic and pharmacokinetic properties, clinical efficacy, and tolerability of telavancin were reviewed.

RESULTS

In vitro, telavancin has potent activity against S aureus, including methicillin-resistant strains; Streptococcus pneumoniae; and vancomycin-susceptible enterococci with MICs generally <1 μg/mL. Telavancin appears to have a dual mechanism of action, inhibiting cell wall formation and disrupting the cell membrane. In Phase III studies (ATLAS 1 and ATLAS 2), telavancin was found to be noninferior to vancomycin, with clinical cure rates of 88.3% and 87.1%, respectively, in clinically evaluable patients in the treatment of cSSSIs (difference, 1.2%; 95% CI, -2.1 to 4.6; P = NS). The effectiveness of telavancin in the treatment of hospital-acquired pneumonia was assessed in 2 Phase III studies (ATTAIN 1 and ATTAIN 2). Preliminary findings were that the effectiveness of telavancin was not significantly different from that of vancomycin, with cure rates of 82.7% and 80.9% in the clinically evaluable population, respectively (difference, 1.8%; 95% CI, -4.1 to 7.7; P = NS). The most commonly (>10%) reported adverse events included taste disturbances, nausea, headache, vomiting, foamy urine, constipation, and insomnia.

CONCLUSION

In clinical trials, the effectiveness of telavancin was not significantly different from that of vancomycin in the treatment of cSSSIs, and telavancin was generally well tolerated.

Molecular characterization of vancomycin-resistant enterococci in a Chinese hospital between 2003 and 2009

From June 2003 to December 2009, 98 isolates of vancomycin-resistant enterococci (VRE) were cultured from clinical specimens taken from patients admitted to a 1,500-bed tertiary-care teaching hospital in Beijing, China. Isolates were characterized by pulsed-field gel electrophoresis and multilocus sequence typing. We investigated the structure of the vanA gene cluster and the distribution of the virulence markers esp, hyl, gelE, asa1, and cylA by polymerase chain reaction. Our results indicate that multilocus sequence typing revealed five novel sequence types and one new allele. VRE faecium (VREfm) isolates were heterogeneous in their vanA cluster types and in the presence of virulence genes. We also observed inconsistency between genotype and phenotype in VREfm isolates. The outbreak with VREfm in our hospital appears polyclonal, whereas VRE faecalis characterization indicated dissemination of a particular clone. After 2007, VRE faecalis was completely replaced by VREfm, which has since been the predominant species in our hospital. VRE appears to be in an evolutionary flux in our hospital.

Complications of mechanical ventilation in the pediatric population

BACKGROUND

Mechanical ventilation (MV) strategies are continuously evolving in an effort to minimize adverse events. The objective of this study was to determine the complications associated with MV in children.

STUDY DESIGN

Prospective observational study. Over a period of 10 consecutive months, 150 patients (median age 0.8 years, IQR 4.4, 59% male) were enrolled in this study.

RESULTS

The median duration of MV was 3.1 days (IQR 3.9). A total of 85 complications were observed in 60 (40%) patients (114 complications per 1,000 ventilation days). 16.7% of patients developed atelectasis, 13.3% post-extubation stridor, 9.3% failed extubation, 2.0% pneumothorax, 3.3% accidental extubation, 2.7% nasal or perioral tissue damage and 1.9% ventilator associated pneumonia. Atelectasis occurred most often in the left lower lobe (36%) or in the right upper lobe (26%). The incidence of atelectasis in children <1 year of age was 12% (31 episodes per 1,000 days of ventilation) compared to 18% (57 episodes per 1,000 days of ventilation) in children ≥ 1 year of age (P < 0.05). Patients that failed extubation were ventilated for a median of 8.5 (IQR 8.8) days compared to 2.9 days (IQR, 3.8) in patients that were successfully extubated (P < 0.01). The absence of an air leak prior to extubation did not correlate with failed extubation. Accidental extubation was limited to orally intubated patients.

CONCLUSION

MV complications occurred in 40% of patients and most often consisted of atelectasis and post-extubation stridor. Further studies are needed to examine associated risk factors and strategies to reduce their occurrence.

Antimicrobial resistance in the intensive care unit: mechanisms, epidemiology, and management of specific resistant pathogens

Infections caused by drug-resistant and multidrug-resistant microbial pathogens pose tremendous challenges to health care systems, including challenges related to the diagnosis, treatment, and containment of these infections. These challenges are amplified in the intensive care unit (ICU), where pressures for selection and emergence of resistance and risks of transmission of resistant pathogens are highest, and where the threat of resistance drives selection of empiric antimicrobial regimens. This article reviews basic concepts of resistance to antibacterial agents including mechanisms and modes of transmission, and discusses management issues for the important drug-resistant pathogens found in the ICU.

[Nosocomial urinary tract infection in critical pediatric patients]

OBJECTIVE

To determine the incidence, etiology and risk factors of nosocomial urinary tract infections (nUTI) in a second level Pediatric Intensive Care Unit (PICU).

PATIENTS AND METHODS

A prospective study of 104 patients admitted to the PICU with a length of stay of more than 48 hours was carried out over a one year period (January to December 2009) to study the incidence and risk factors of nUTI. Urine samples were collected and cultured in all patients admitted for more than 48 hours to our PICU. Those needing indwelling urinary catheters had urine samples collected upon admission and every 24 hours until catheter retrieval, while those who did not need catheters had samples collected upon admission and every 48 hours until discharge from the PICU.

RESULTS

Six patients (5.8% of those admitted) were diagnosed of nUTI, with an incidence density of 5/1000 patients/day and 12.2/1000 catheterization days. Four of these were caused by E. coli (including a multiresistant strain), and two by C. albicans. Patients suffering nUTIs had significantly more relevant medical antecedents and a longer period of admittance than patients without nUTI. A statistically nonsignificant tendency towards increased infection risk was also found in younger patients and in those who needed an indwelling catheter for longer periods.

CONCLUSIONS

We found a higher incidence density of catheter associated nUTI than in other reports. This at least partially could be due to the characteristics of our patients, and to the exhaustive methodology used for detection.

Influence of tracheostomy on the incidence of catheter-related bloodstream infection in the catheterization of jugular vein by posterior access

There are no data about the influence of tracheostomy in the incidence of catheter-related bloodstream infection (CRBSI) on the catheterization of the jugular vein by posterior access and there are no recommendations relating to this circumstance in the guidelines of the Centers for Disease Control and Prevention (CDC) and of Healthcare Epidemiology of America/Infectious Diseases Society of America (SHEA/IDSA) for the prevention of CRBSI. The novel finding of this observational study was that there was a higher incidence of CRBSI in the catheterization of jugular vein by posterior access in patients with tracheostomy than without it (13.24 vs 0 episodes of CRBSI per 1,000 catheter-day; odds ratio = 23.92; 95% CI = 1.86-infinite; p = 0.008). Thus, the presence of tracheostomy is a risk factor of CRBSI on the catheterization of jugular vein by posterior access.

Time-dependent analysis of length of stay and mortality due to urinary tract infections in ten developing countries: INICC findings

OBJECTIVES

To estimate the excess length of stay (LOS) and mortality in an intensive care unit (ICU) due to a Catheter associated urinary tract infections (CAUTI), using a statistical model that accounts for the timing of infection in 29 ICUs from 10 countries: Argentina, Brazil, Colombia, Greece, India, Lebanon, Mexico, Morocco, Peru, and Turkey.

METHODS

To estimate the extra LOS due to infection in a cohort of 69,248 admissions followed for 371,452 days in 29 ICUs, we used a multi-state model, including specific censoring to ensure that we estimate the independent effect of urinary tract infection, and not the combined effects of multiple infections. We estimated the extra length of stay and increased risk of death independently in each country, and then combined the results using a random effects meta-analysis.

RESULTS

A CAUTI prolonged length of ICU stay by an average of 1.59 days (95% CI: 0.58, 2.59 days), and increased the risk of death by 15% (95% CI: 3, 28%).

CONCLUSIONS

A CAUTI leads to a small increased LOS in ICU. The increased risk of death due to CAUTI may be due to confounding with patient morbidity.

Nosocomial methicillin resistant Staphylococcus aureus pneumonia - epidemiology and trends based on data of a network of 586 German ICUs (2005-2009)

The epidemiology of MRSA pneumonia varies across countries. One of the most import risk factors for the development of nosocomial MRSA pneumonia is mechanical ventilation. Methicillin resistance in S. aureus ventilator associated pneumonia (VAP) ranged between 37% in German, 54% in the US American and 78% in Asian and Latin American ICUs. In 2009, the incidence density of nosocomial VAP caused by MRSA was 0.28 per 1000 ventilation days in a network of 586 German ICUs. Incidences peaked in neurological and neurosurgical ICUs. Crude hospital mortality in studies performed after 2005 lay between 27% and 59% and attributable MRSA pneumonia mortality at 40%. Since 2005, US American and German data indicate decreasing trends for MRSA pneumonia. Measures to reduce MRSA pneumonia or to control the spread of MRSA include hand hygiene, standard and contact precautions, oral contamination with chlor hexidine, skin decontamination with antiseptics, screening, and (possibly) patient isolation in a single room.

Disruption of the alternative pathway convertase occurs at the staphylococcal surface via the acquisition of factor H by Staphylococcus aureus

Staphylococcus aureus is a significant human pathogen that causes skin-structure, invasive, and hospital-associated infections worldwide. The complement system is vital to innate defense against many bacterial infections. As shown with other pathogens, mechanisms for circumventing complement attack may include recruitment of the complement regulatory protein factor H (fH). In the present study, we show that S. aureus binds fH in a dose-dependent and time-dependent manner. Interestingly, this interaction does not require complement activation nor C3-fragment presence and occurs efficiently in the absence of other serum components suggesting a mechanism other than bridging between intermediary molecules. However, fH binding is greater when incubated with normal human serum compared to heat-inactivated serum, which suggests that complement activation may enhance fH binding. S. aureus-bound fH was found to inhibit the alternative pathway through disruption of the alternative pathway C3 convertase as shown by an increase in Bb release and a decrease in total C3-fragment deposition. Furthermore, S. aureus-bound fH retains cofactor activity for factor-I mediated cleavage of C3b. These studies show that the acquisition of fH to the S. aureus surface inhibits complement-mediated opsonization via disruption of the alternative pathway convertase; thus, we report an immune-evasion mechanism not previously described for S. aureus.

Urban focus of Rickettsia typhi and Rickettsia felis in Los Angeles, California

Classic murine typhus, caused by Rickettsia typhi, is endemic in the continental United States in areas of Texas and southern California. We conducted an environmental investigation in an urban area of Los Angeles identified as the probable exposure site for a case of murine typhus. Four Rattus norvegicus heavily infested with Xenopsylla cheopis (average 32.5 fleas per animal, range 20-42) were trapped, and fleas, blood, and tissues were collected. DNAs from all specimens were tested for R. typhi and Rickettsia felis using a TaqMan assay targeting the rickettsial citrate synthase gene. Although rickettsiemia was not detected, DNA of R. felis was detected in at least one tissue from each rat. Tissues from 3 rats were also positive for R. typhi DNA. R. typhi and R. felis DNAs were detected in fleas collected from each animal with average minimal infection rates of 10% and 32.3%, respectively. Although R. typhi still circulates in urban Los Angeles in the classic Oriental flea-rat cycle, R. felis is more prevalent, even in this association.

Impact of International Nosocomial Infection Control Consortium (INICC) strategy on central line-associated bloodstream infection rates in the intensive care units of 15 developing countries

BACKGROUND

The International Nosocomial Infection Control Consortium (INICC) was established in 15 developing countries to reduce infection rates in resource-limited hospitals by focusing on education and feedback of outcome surveillance (infection rates) and process surveillance (adherence to infection control measures). We report a time-sequence analysis of the effectiveness of this approach in reducing rates of central line-associated bloodstream infection (CLABSI) and associated deaths in 86 intensive care units with a minimum of 6-month INICC membership.

METHODS

Pooled CLABSI rates during the first 3 months (baseline) were compared with rates at 6-month intervals during the first 24 months in 53,719 patients (190,905 central line-days). Process surveillance results at baseline were compared with intervention period data.

RESULTS

During the first 6 months, CLABSI incidence decreased by 33% (from 14.5 to 9.7 CLABSIs per 1,000 central line-days). Over the first 24 months there was a cumulative reduction from baseline of 54% (from 16.0 to 7.4 CLABSIs per 1,000 central line-days; relative risk, 0.46 [95% confidence interval, 0.33-0.63]; P < .001). The number of deaths in patients with CLABSI decreased by 58%. During the intervention period, hand hygiene adherence improved from 50% to 60% (P < .001); the percentage of intensive care units that used maximal sterile barriers at insertion increased from 45% to 85% (P < .001), that adopted chlorhexidine for antisepsis increased from 7% to 27% (P < .001), and that sought to remove unneeded catheters increased from 37% to 83% (P < .001); and the duration of central line placement decreased from 4.1 to 3.5 days (P < .001).

CONCLUSIONS

Education, performance feedback, and outcome and process surveillance of CLABSI rates significantly improved infection control adherence, reducing the CLABSI incidence by 54% and the number of CLABSI-associated deaths by 58% in INICC hospitals during the first 2 years.

Escherichia coli O25b-ST131: a pandemic, multiresistant, community-associated strain

Escherichia coli sequence type 131 (ST131) is a worldwide pandemic clone, causing predominantly community-onset antimicrobial-resistant infection. Its pandemic spread was identified in 2008 by utilizing multilocus sequence typing (MLST) of CTX-M-15 extended-spectrum β-lactamase-producing E. coli from three continents. Subsequent research has confirmed the worldwide prevalence of ST131 harbouring a broad range of virulence and resistance genes on a transferable plasmid. A high prevalence of the clone (∼30%-60%) has been identified amongst fluoroquinolone-resistant E. coli. In addition, it potentially harbours a variety of β-lactamase genes; most often, these include CTX-M family β-lactamases, and, less frequently, TEM, SHV and CMY β-lactamases. Our knowledge of ST131's geographical distribution is incomplete. A broad distribution has been demonstrated amongst antimicrobial-resistant E. coli from human infection in Europe (particularly the UK), North America, Canada, Japan and Korea. High rates are suggested from limited data in Asia, the Middle East and Africa. The clone has also been detected in companion animals, non-companion animals and foods. The clinical spectrum of disease described is similar to that for other E. coli, with urinary tract infection predominant. This can range from cystitis to life-threatening sepsis. Infection occurs in humans of all ages. Therapy must be tailored to the antimicrobial resistance phenotype of the infecting isolate and the site of infection. Phenotypic detection of the ST131 clone is not possible and DNA-based techniques, including MLST and PCR, are described.

Diagnosis, management and prevention of ventilator-associated pneumonia: an update

Ventilator-associated pneumonia (VAP) affects 10-20% of mechanically ventilated patients and is associated with increased morbidity and mortality and high costs. Early diagnosis is crucial for rapid appropriate antimicrobial therapy to be instituted, but debate remains as to the optimal diagnostic strategy. Noninvasive clinical-based diagnosis is rapid but may not be as accurate as invasive techniques. Increased use of biomarkers and advances in genomics and proteomics may help speed up diagnosis. Management of VAP relies principally on appropriate antimicrobial therapy, which should be selected according to individual patient factors, such as previous antibacterial therapy and length of hospitalization or mechanical ventilation, and local infection and resistance patterns. In addition, once bacterial culture and sensitivity results are available, broad-spectrum therapy should be de-escalated to provide a more specific, narrower-spectrum cover. Optimum duration of antibacterial therapy is difficult to define and should be tailored to clinical response. Biomarker levels may be useful to monitor response to therapy. With the high morbidity and mortality, prevention of VAP is important and several strategies have been shown to reduce the rates of VAP in mechanically ventilated patients, including using noninvasive ventilation where possible, and semi-recumbent positioning. Other potentially beneficial preventive techniques include subglottal suctioning, oral decontamination strategies and antimicrobial-coated endotracheal tubes, although further study is needed to confirm the cost effectiveness of these strategies.

Murine typhus as a cause of Fever in travelers from Tunisia and mediterranean areas

BACKGROUND

Travelers are exposed to a variety of health risks in unfamiliar environments and fever is a common problem in patients returning from travel abroad. Rickettsial diseases are increasingly frequently being reported among international travelers. Here we present cases of Rickettsia typhi infection, the agent of murine typhus, that were identified in our laboratory the last year, in travelers from Tunisia.

METHODS

For each patient we tested an acute-phase serum sample and for one patient we tested a convalescent-phase serum sample. IgG and IgM antibody titers were estimated with use of the microimmunofluorescence (MIF) assay. Western blot (WB) assay was performed for all the patients.

RESULTS

We identified three cases of murine typhus after a travel in Tunisia. All cases were observed during late summer and early autumn and patients were suffering by persistent fever. None of them presented rash or inoculation eschar. MIF was positive for Rickettsia sp. in the acute-phase serum samples of two patients. In one patient, two acute-phase serum samples were Rickettsia sp. negative whereas a third convalescent-phase serum sample that was obtained 2 weeks after was Rickettsia sp. positive. By WB assay we identified infection by R typhi. A treatment was immediately started and patients became apyretic.

CONCLUSIONS

In the countries of North Europe, although autochthones cases of murine typhus have not been described, sporadic cases of R typhi infection are identified in travelers who visited murine typhus endemic areas. Murine typhus should be considered in the diagnosis of febrile illness without rash in travelers returning from disease endemic areas, like the south Mediterranean area.

Blood cultures: key elements for best practices and future directions

Bloodstream infections (BSI) cause significant morbidity and mortality among populations worldwide. Blood cultures (BCs) are regarded as the "gold standard" for diagnosis of bacteremia and are among the most important functions of the clinical microbiology laboratory. Significant changes in the methods and techniques of obtaining BCs have occurred since the first inception of BCs into clinical practice. Aside from significant improvements of established, conventional technology, new assays for diagnosis of bacteremia and fungemia, particularly those involving molecular techniques, are now available. BCs must be collected under sterile conditions and guidelines for appropriate collection, processing, and results reporting of BCs have been established. This review provides comprehensive information on optimal BC practices for laboratories, utilizing traditional approaches and emerging technology. As laboratories and clinicians must appreciate the key factors affecting the use of these techniques, improved communication between laboratory personnel and clinicians regarding such elements as duration of incubation, workup of contaminants and critical action value reporting will greatly improve the diagnostic approach to BSI.

Effect of anaesthesia maintained with sevoflurane and propofol on surgical site infection after elective open gastrointestinal surgery

Perioperative increase in oxidative activity in surgical patients reportedly prevents postoperative surgical site infection (SSI). Several clinical studies have shown that oxidative activity under sevoflurane anaesthesia was higher than that under propofol anaesthesia. Therefore, we hypothesised that sevoflurane anaesthesia would discourage SSI compared with propofol anaesthesia. To examine the effect of anaesthesia maintained with sevoflurane and propofol on SSI, a total of 265 consecutive adult patients, with American Society of Anesthesiologists physical status 1-3, who underwent elective open gastrointestinal surgery under general anaesthesia, were surveyed for SSI between January 2007 and December 2008. Sevoflurane or propofol was selected to maintain anaesthesia in 95 and 170 patients, respectively. A propensity score was used for pairwise matching of these patients to avoid selection biases between the two methods of anaesthesia. Propensity matching yielded 84 pairs of patients. We compared standardised infection ratios (SIRs), i.e. the quotient of the number of SSI cases observed and the number of SSI cases expected, calculated using data from the National Nosocomial Infection Surveillance, between sevoflurane and propofol anaesthesia. After propensity matching, SIR after sevoflurane anaesthesia was 1.89 [95% confidence interval (CI): 1.46-2.32], which was significantly lower than after propofol anaesthesia (4.78; 95% CI: 4.30-5.27) (P=0.02). This study suggests that sevoflurane tends to suppress SSI after elective open gastrointestinal surgery compared with propofol.

A rare case of silicone mammary implant infection by Streptomyces spp. in a patient with breast reconstruction after mastectomy: taxonomic characterization using molecular techniques

A Streptomyces sp. isolated from a patient who had had breast reconstruction after a mastectomy was identified at the species level by comparative sequence analysis of 16S ribosomal DNA (rDNA) and the hypervariable alpha-region of the 16S rDNA.