Nosocomial Bloodstream Infections Research Articles

Route of nutrition and risk of blood stream infections in critically ill patients; a comparative study

The association of nutritional support practices with intensive care unit (ICU) - acquired infections is a current field of interest. The objective of this study was to determine whether different routes of delivery of nutritional support are associated with a different risk of bloodstream infection (BSI) in critically ill patients. An observational study in a multidisciplinary ICU. Adult ICU patients, with ICU stay ≥96h who were fed artificially were included. Patients were grouped into three categories of nutrition support routes: those on enteral nutrition alone (EN group), on parenteral nutrition alone (PN group) or on both EN and PN (EN+PN group). Illness severity, co-morbidities and routine laboratory values were recorded on ICU admission. Route of feeding, caloric, protein and immunonutrient intake was recorded daily for each patient. Nosocomial BSIs were identified by infection control surveillance methods. The incidence of BSI among the three groups was compared with Kaplan-Meier plots and Cox proportional-hazards models. A total of 249 patients were included in the analysis. There were no significant differences between groups in illness severity scores and in the time to nutritional support initiation (median time 48 [24-48] hours). The median daily caloric intake was significantly lower for the EN group than for patients of PN and EN+PN group (415 [157-687] kcal vs. 1077 [297-2087] kcal and 1292 [890-1819] kcal respectively, p<0.001). BSI occurred in 69 (27.7%) patients. Bivariate Cox analysis revealed that APACHE II score and admission category were significantly associated to BSI development [hazard ratio (HR), 1.05; 95% confidence interval (CI), 1.01-1.09 and HR 0.45; 95% CI 0.18-1.15, respectively]. Presence of co-morbidities, SOFA score, hospital length of stay (LOS) before ICU admission, late initial feeding, serum albumin at admission, average daily maximum concentration of serum glucose, caloric, protein and immunonutrient intake did not affect the hazard of BSI development. After adjustment for the confounding variables, in a multivariate analysis, patients of the EN+PN group had lower incidence of BSI than the other two groups (HR 0.30; 95% CI 0.17-0.53), irrespective of the number of days of PN intake and the percentage of calories received from PN. There was no difference in the hazard for BSI development between the EN and PN group. Patients with EN+PN had a significantly longer ICU-LOS whereas mortality was not different among the three groups. In this retrospective analysis of 249 consecutively enrolled ICU patients, we found that in critically ill patients EN+PN feeding strategy was associated with a significantly reduced hazard of BSI development, compared to EN or PN route of nutritional support.

Epidemiology and Microbiologic Characterization of Nosocomial Candidemia from a Brazilian National Surveillance Program.

Candidemia is a growing problem in hospitals all over the world. Despite advances in the medical support of critically ill patients, candidiasis leads to prolonged hospitalization, and has a crude mortality rate around 50%. We conducted a multicenter surveillance study in 16 hospitals distributed across five regions of Brazil to assess the incidence, species distribution, antifungal susceptibility, and risk factors for bloodstream infections due to Candida species. From June 2007 to March 2010, we studied a total of 2,563 nosocomial bloodstream infection (nBSI) episodes. Candida spp. was the 7th most prevalent agent. Most of the patients were male, with a median age of 56 years. A total of 64 patients (46.7%) were in the ICU when candidemia occurred. Malignancies were the most common underlying condition (32%). The crude mortality rate of candidemia during the hospital admission was 72.2%. Non-albicans species of Candida accounted for 65.7% of the 137 yeast isolates. C. albicans (34.3%), Candida parapsilosis (24.1%), Candida tropicalis (15.3%) and Candida glabrata (10.2%) were the most prevalent species. Only 47 out of 137 Candida isolates were sent to the reference laboratory for antifungal susceptibility testing. All C. albicans, C. tropicalis and C. parapsilosis isolates were susceptible to the 5 antifungal drugs tested. Among 11 C. glabrata isolates, 36% were resistant to fluconazole, and 64% SDD. All of them were susceptible to anidulafungin and amphotericin B. We observed that C. glabrata is emerging as a major player among non-albicans Candida spp. and fluconazole resistance was primarily confined to C. glabrata and C. krusei strains. Candida resistance to echinocandins and amphotericin B remains rare in Brazil.Mortality rates remain increasingly higher than that observed in the Northern Hemisphere countries, emphasizing the need for improving local practices of clinical management of candidemia, including early diagnosis, source control and precise antifungal therapy.

Draft Genome Sequences of Two Multidrug-Resistant Extended-Spectrum-β-Lactamase-Producing Klebsiella pneumoniae Strains Causing Bloodstream Infections.

Multidrug-resistant (MDR) Klebsiella pneumoniae has become a major contributor to nosocomial bloodstream infections. Here, we report the draft genome sequences of two MDR extended-spectrum-β-lactamase-producing strains causing bloodstream infections. These sequenced genomes display a wide-spectrum virulence arsenal and will help us understand the genomic basis of K. pneumoniae virulence.

CXCR1-mediated neutrophil degranulation and fungal killing promote Candida clearance and host survival.

Systemic Candida albicans infection causes high morbidity and mortality and is now the leading cause of nosocomial bloodstream infection in the United States. Neutropenia is a major risk factor for poor outcome in infected patients; however, the molecular factors that mediate neutrophil trafficking and effector function during infection are poorly defined. Using a mouse model of systemic candidiasis, we found that the neutrophil-selective CXC chemokine receptor Cxcr1 and its ligand, Cxcl5, are highly induced in the Candida-infected kidney, the target organ in the model. To investigate the role of Cxcr1 in antifungal host defense in vivo, we generated Cxcr1(-/-) mice and analyzed their immune response to Candida. Mice lacking Cxcr1 exhibited decreased survival with enhanced Candida growth in the kidney and renal failure. Increased susceptibility of Cxcr1(-/-) mice to systemic candidiasis was not due to impaired neutrophil trafficking from the blood into the infected kidney but was the result of defective killing of the fungus by neutrophils that exhibited a cell-intrinsic decrease in degranulation. In humans, the mutant CXCR1 allele CXCR1-T276 results in impaired neutrophil degranulation and fungal killing and was associated with increased risk of disseminated candidiasis in infected patients. Together, our data demonstrate a biological function for mouse Cxcr1 in vivo and indicate that CXCR1-dependent neutrophil effector function is a critical innate protective mechanism of fungal clearance and host survival in systemic candidiasis.

Characterization of carbapenem-resistant Acinetobacter calcoaceticus-baumannii complex isolates from nosocomial bloodstream infections in southern Iran.

Acinetobacter baumannii is an important opportunistic bacterial pathogen responsible for serious infections in hospitalized patients. From a total of 78 consecutive non-repetitive Acinetobacter spp. isolates from patients with blood infections, 61 were carbapenem resistant, which were positive for blaOXA-51-like (96.7%), blaOXA-23-like (77 %), blaOXA-58-like (8.1%) and blaOXA-40-like genes (32.8%) by multiplex PCR. The isolates were identified as A. baumannii (n = 59) and Acinetobacter nosocomialis (n = 2). Also, we found a case of Acinetobacter junii, causing bacteraemia, that possessed the IMP gene. High levels of resistance were observed to fluoroquinolones, aminoglycosides, tigecycline and to the beta-lactam antibiotics, including piperacillin/tazobactam and ampicillin/sulbactam. ISAba1 was present in 96.7% of all Acinetobacter calcoaceticus-baumannii complex (Acb) isolates. Also, 33 (54.1%) and 23 (37.7%) isolates harboured ISAba1 upstream of blaOXA-23-like and blaOXA-51-like genes, respectively, though this was not observed in A. nosocomialis isolates. No relationship was observed between the presence of ISAba1 upstream of oxacillinase genes and the level of carbapenem resistance in all Acb isolates. Only two genes encoding metallo-beta-lactamase (VIM, SPM) were detected in all Acb isolates. This suggests that carbapenem resistance in blood-isolate Acb is mostly due to the presence of acquired carbapenemases. This is the first report from Iran on the identification of A. nosocomialis isolates that possess multiple oxacillinase genes and lack upstream ISAba1.

A 5-year Surveillance Study on Antimicrobial Resistance ofAcinetobacter baumanniiClinical Isolates from a Tertiary Greek Hospital

BackgroundAcinetobacter baumannii has emerged as a major cause of nosocomial outbreaks. It is particularly associated with nosocomial pneumonia and bloodstream infections in immunocompromised and debilitated patients with serious underlying pathologies. Over the last two decades, a remarkable rise in the rates of multidrug resistance to most antimicrobial agents that are active against A. baumannii has been noted worldwide. We evaluated the rates of antimicrobial resistance and changes in resistance over a 5-year period (2010–2014) in A. baumannii strains isolated from hospitalized patients in a tertiary Greek hospital.Materials and MethodsIdentification of A. baumannii was performed by standard biochemical methods and the Vitek 2 automated system, which was also used for susceptibility testing against 18 antibiotics: ampicillin/sulbactam, ticarcillin, ticarcillin/clavulanic acid, piperacillin, piperacillin/tazobactam, cefotaxime, ceftazidime, cefepime, imipenem, meropenem, gentamicin, amikacin, tobramycin, ciprofloxacin, tetracycline, tigecycline, trimethoprim/sulfamethoxazole, and colistin. Interpretation of susceptibility results was based on the Clinical and Laboratory Standards Institute criteria, except for tigecycline, for which the Food and Drug Administration breakpoints were applied. Multidrug resistance was defined as resistance to ≥3 classes of antimicrobial agents.ResultsOverall 914 clinical isolates of A. baumannii were recovered from the intensive care unit (ICU) (n = 493), and medical (n = 252) and surgical (n = 169) wards. Only 4.9% of these isolates were fully susceptible to the antimicrobials tested, while 92.89% of them were multidrug resistant (MDR), i.e., resistant to ≥3 classes of antibiotics. ICU isolates were the most resistant followed by isolates from surgical and medical wards. The most effective antimicrobial agents were, in descending order: colistin, amikacin, trimethoprim/sulfamethoxazole, tigecycline, and tobramycin. Nevertheless, with the exception of colistin, no antibiotic was associated with a susceptibility rate >40% for the entire study period. The most common phenotype showed resistance against ampicillin/sulbactam, cephalosporins, carbapenems, aminoglycosides, ciprofloxacin, and tigecycline. An extremely concerning increase in colistin-resistant isolates (7.9%) was noted in 2014, the most recent study year.ConclusionThe vast majority of A. baumannii clinical isolates in our hospital are MDR. The remaining therapeutic options for critically ill patients who suffer from MDR A. baumannii infections are severely limited, with A. baumannii beginning to develop resistance even against colistin. Scrupulous application of infection control practices should be implemented in every hospital unit. Lastly, given the lack of available therapeutic options for MDR A. baumannii infections, well-controlled clinical trials of combinations of existing antibiotics are clearly needed.

Usefulness of Multiplex Real-Time PCR for Simultaneous Pathogen Detection and Resistance Profiling of Staphylococcal Bacteremia.

Staphylococci are the leading cause of nosocomial blood stream infections. Fast and accurate identification of staphylococci and confirmation of their methicillin resistance are crucial for immediate treatment with effective antibiotics. A multiplex real-time PCR assay that targets mecA, femA specific for S. aureus, femA specific for S. epidermidis, 16S rRNA for universal bacteria, and 16S rRNA specific for staphylococci was developed and evaluated with 290 clinical blood culture samples containing Gram-positive cocci in clusters (GPCC). For the 262 blood cultures identified to the species level with the MicroScan WalkAway system (Siemens Healthcare Diagnostics, USA), the direct real-time PCR assay of positive blood cultures showed very good agreement for the categorization of staphylococci into methicillin-resistant S. aureus (MRSA), methicillin-susceptible S. aureus (MSSA), methicillin-resistant S. epidermidis (MRSE), methicillin-susceptible S. epidermidis (MSSE), methicillin-resistant non-S. epidermidis CoNS (MRCoNS), and methicillin-susceptible non-S. epidermidis CoNS (MSCoNS) (κ = 0.9313). The direct multiplex real-time PCR assay of positive blood cultures containing GPCC can provide essential information at the critical point of infection with a turnaround time of no more than 4 h. Further studies should evaluate the clinical outcome of using this rapid real-time PCR assay in glycopeptide antibiotic therapy in clinical settings.

Candidemia: Speciation and Antifungal susceptibility testing from a Tertiary Care Hospital in Maharashtra, India

Introduction: Invasive fungal infections are an important nosocomial health problem, candidal infections being the most common. Candidal bloodstream infections (BSIs) account for one-fourth of the nosocomial BSIs. Candida albicans once the most common has now been replaced by nonalbicans Candida, accounting for majority of cases of candidal infections. The knowledge and understanding of specific risk factors, epidemiology, prophylactic measures, and outcomes with relation to speciation are changing rapidly. Emergence of antifungal resistance is a cause of concern. With this background, a prospective study was undertaken. Aims and Objectives: To isolate Candida spp. from blood cultures of patients with clinically diagnosed or suspected septicemia; to identify and speciate Candida isolates and carry out the antifungal susceptibility test; to determine incidence of candidemia; to find out the crude mortality rate in candidemia patients. Materials and Methods: Blood cultures received in the Department of Microbiology from various critical care units over a 1-year period were included in this study. Samples were cultured on Sabouraud dextrose agar and routine bacteriological cultures. Speciation of suspected Candida growth was done by conventional and automated system. Results: A total of 225 out of 839 blood cultures were culture positive. A total of 196 were bacterial pathogens. Candida spp. were isolated in 29 samples. These included 10 cases of Candida tropicalis, 8 Candida parapsilosis, and three cases each of C. albicans and Candida krusei. Fluconazole resistance was seen (minimum inhibitory concentration ≥64 μg/ml) in 4 isolates, 2 of C. krusei and 2 of Candida haemulonii. Incidence of candidemia was 3.46%. Crude mortality rate in the present study was 24%.

Microbial Colonization of Intravascular Catheters Inserted in Newborn Babies: A Descriptive Study

Introduction: Colonization and subsequent bloodstream infection of the intravascular catheters is the common cause of nosocomial bloodstream infection in newborn babies. This study was performed to determine the microbial colonization of intravascular catheters inserted in newborn babies in Special Care Baby Unit (SCBU) of 550-bedded Children Hospital, Mandalay from January to September, 2015. Methods: Eighty-four newborn babies with or without clinical sepsis were chosen as the study population and their intravascular catheters were cultured by semi quantitative (roll plate) method. Peripheral blood samples from 35 patients with clinical sepsis in the presence of intravascular catheter were cultured by conventional method. Antimicrobial susceptibility test was performed according to CLSI. Results: The occurrence of microbial colonization was 17.9% (15/84) and no case of catheter-related bloodstream infection (CRBSI).Coagulase-negative staphylococci (CoNS) was the predominant microorganism (8/53.3%), followed by Staphylococcus aureus (5/33.3%), Enterococcus species (1/6.7%) and Enterobacter species (1/6.7%). 25% of CoNS were methicillin-resistant and methicillin-resistant Staphylococcus aureus (MRSA) was occurred in 80% of the species. Isolated Enterococcus species was resistant to cloxacillin, oxacillin and Enterobacter species was resistant to gentamicin and cefotaxime. Conclusions: Therefore, this study elicited the occurrence of microbial colonization on inserted intravascular catheters and their susceptibility patterns which will help the pediatricians in the choice of antibiotics and will give a useful healthcare advice on the control of nosocomial bloodstream infection.

Clinical significance of coagulase-negative staphylococci isolates from nosocomial bloodstream infections

Background Identification of coagulase-negative staphylococci (CoNS) as nosocomial pathogens or contaminants is significant for microbiologists and clinicians. This study aimed to determine the frequency of isolation and antimicrobial resistance patterns of CoNS isolates from nosocomial bloodstream infections (BSIs) and to identify risk factors associated with true bacteremia caused by these emerging pathogens in a Saudi tertiary care hospital. Methods All CoNS-positive cultures from inpatients were identified using the standard methods during a 10-month period. Antimicrobial susceptibility testing was done using the reference broth microdilution method. Results A total of 208 isolates were identified; of these 75 (32.2%) were considered infection associated, and 133 (67.8%) were considered contamination. S. epidermidis accounted for 34.7% of bacteremia cases, followed by S. hominis (21.3%), S. haemolyticus (16%), and S. saprophyticus (12%). Central venous catheters (p ≤ 0.0001), prior antibiotic therapy (p ≤ 0.0001), the occurrence of more than one positive blood culture (p ≤ 0.0001), and intensive care unit (ICU) admission (p = 0.007) were all independently associated with CoNS bacteremia. Overall, all isolates were highly resistant to penicillin (94.7%), oxacillin (90.7%), and erythromycin (85.3%). The rates of susceptibility to vancomycin, daptomycin, and teicoplanin were 98.7%, 98.7%, and 93.3%, respectively. Conclusions Our results further highlight that accurate identification and susceptibility testing of CoNS isolates from nosocomial BSIs are crucial to minimize excessive antibiotic use and unnecessary catheter removal. In addition, daptomycin may be an efficient alternative therapeutic option for CoNS resistant to oxacillin and other commonly used antibiotics.

Incidence of Central Venous Catheter-Related Infection and Risk Factors in Critically Ill Post-Operative Cancer Patients: A Randomized Prospective Cohort Study

Background: Cancer patients are susceptive to infection. Catheter-related bloodstream infections are the first cause of nosocomial bloodstream infections in intensive care units. Objectives: The aim of this study was to evaluate the association between the type of central intravenous catheter and bloodstream infection in post-operative cancer surgery patients at surgery intensive care units (ICU). Methods: In a randomized, non-blind study, 66 cancer surgery patients were studied. The primary aim was rate of central venous catheter-related infection by type of catheter. The patients were enrolled in three groups: simple catheter (n = 23) (without antimi- crobial), impregnated catheter in the internal part (n = 28), and AGB + catheter (n = 15) (impregnated catheter in external and internal part); all catheters were triple lumen, polyurethane (arrow, chlorhexidine and silver sulfadiazine, USA). Insertion of catheters was done in full sterile conditions based on the center for disease control (CDC) guidelines for the prevention of intravascular catheter- related infection. Catheter related infection was confirmed by positive blood culture of blood samples of central catheter. The chi square or Fisher's exact test was used to compare base values and dierence in rate of colonization and bloodstream catheter-related

Nosocomial bloodstream infections caused by Escherichia coli and Klebsiella pneumoniae resistant to third-generation cephalosporins, Finland, 1999–2013: Trends, patient characteristics and mortality

Background: Few systematically collected multi-centre surveillance data on nosocomial bloodstream infections (BSI) caused by extended-spectrum β-lactamase (ESBL) producing Escherichia coli or Klebsiella pneumoniae have been published. Aim: To evaluate trends, patient characteristics and mortality of such infections, nosocomial BSI data reported by the 4–17 hospitals participating in the prospective laboratory-based surveillance during 1999–2013 were analysed. Methods: Data were collected by local infection control nurses, patient-days were obtained from the hospital’s administrative database, and dates of deaths from the population registry. Resistance to third-generation cephalosporins was further examined in the national reference laboratory. Findings: A total of 16 028 nosocomial BSIs were identified; 2217 (14%) were caused by E. coli and 661 (4%) by K. pneumoniae; 207 (7%) were non-susceptible to third-generation cephalosporins, with an increasing trend from 0% in 1999 to 17% in 2013. Patient characteristics did not differ significantly between BSIs caused by third-generation susceptible and resistant E. coli and K. pneumonia, but the case fatality tended to be higher. Most (88%) of the isolates reported as non-susceptible to third-generation cephalosporins had ESBL phenotype, CTX-M (79%) being the most common enzyme. Conclusion: A sharp increase in nosocomial BSIs caused by ESBL producing bacteria was observed. Identification of patients for screening pose a challenge, emphasising the role of infection control guidelines and antibiotic policy in prevention

Risk Factors and Outcomes for Bloodstream Infections Secondary to Clostridium difficile Infection.

We determined the incidence, risk factors, and outcomes of bloodstream infections (BSI) subsequent to Clostridium difficile infection (CDI). We performed a retrospective study of all patients with definite diagnosis of CDI admitted from January 2014 to December 2014 in two large hospitals in Rome. Two groups of patients were analyzed: those with CDI and subsequent BSI (CDI/BSI(+)) and those with CDI and no evidence of primary BSI (CDI/BSI(-)). Data about clinical features, microbiology, treatments, and mortality were obtained. Overall, 393 cases of CDI were included in the final analysis: 72 developed a primary nosocomial BSI, while 321 had CDI without microbiological and clinical evidence of BSI. Etiologic agents of BSI were Candida species (47.3%), Enterobacteriaceae (19.4%), enterococci (13.9%), and mixed infections (19.4%). In multivariate analysis, ribotype 027 status (odds ratio [OR], 6.5), CDI recurrence (OR, 5.5), severe CDI infection (OR, 8.3), and oral vancomycin at >500 mg/day (OR, 3.1) were recognized as factors independently associated with the development of nosocomial BSI. Thirty-day mortality from CDI diagnosis was higher for patients of the CDI/BSI(+) group than for the controls (38.9 versus 13.1%; P < 0.001). Among patients of the CDI/BSI(+) group, mortality attributable to primary BSI was as high as 57%. Our findings suggest that severe CDI is complicated by the development of nosocomial BSI. Candida species and enteric bacteria appear to be the leading causative pathogens and are associated with poor outcomes.

Outcomes in Documented Pseudomonas aeruginosa Bacteremia Treated with Intermittent IV Infusion of Ceftazidime, Meropenem, or Piperacillin-Tazobactam: A Retrospective Study.

Pseudomonas aeruginosa, one of the leading causes of nosocomial gram-negative bloodstream infections, is particularly difficult to treat because of its multiple resistance mechanisms combined with a lack of novel antipseudomonal antibiotics. Despite knowledge of time-dependent killing with ß-lactam antibiotics, most hospitals in Canada currently administer ß-lactam antibiotics by intermittent rather than extended infusions. To determine clinical outcomes, microbiological outcomes, total hospital costs, and infection-related costs for patients with P. aeruginosa bacteremia who received intermittent IV administration of antipseudomonal ß-lactam antibiotics in a tertiary care institution. For this retrospective descriptive study, data were collected for patients who were admitted between March 1, 2005, and March 31, 2013, who had P. aeruginosa bacteremia during their admission, and who received at least 72 h of treatment with ceftazidime, meropenem, or piperacillin-tazobactam. Clinical and microbiological outcomes were determined, and total and infection-related hospital costs were calculated. A total of 103 patients were included in the analysis, of whom 79 (77%) experienced clinical cure. In addition, bacterial eradication was achieved in 41 (87%) of the 47 patients with evaluable data for this outcome. Twenty-eight (27%) of the 103 patients died within 30 days of discontinuation of antipseudomonal ß-lactam antibiotic therapy. The median total cost of the hospital stay was $121 718, and the median infection-related cost was $29 697. P. aeruginosa bacteremia is a clinically significant nosocomial infection that continues to cause considerable mortality and health care costs. To the authors' knowledge, no previous studies have calculated total and infection-related hospital costs for treatment of P. aeruginosa bacteremia with intermittent infusion of antipseudomonal ß-lactam antibiotics, with characterization of cost according to site of acquisition of the infection. This study may provide important baseline data for assessing the impact of implementing extended-infusion ß-lactam therapy, antimicrobial stewardship, and infection control strategies targeting P. aeruginosa infection in hospitalized patients.

Origin of Long-Term Storage Stability and Nitric Oxide Release Behavior of CarboSil Polymer Doped with S-Nitroso-N-acetyl-D-penicillamine.

The prolonged and localized delivery of nitric oxide (NO), a potent antithrombotic and antimicrobial agent, has many potential biomedical applications. In this work, the origin of the long-term storage stability and sustained NO release mechanism of S-nitroso-N-acetyl-d-penicillamine (SNAP)-doped CarboSil 20 80A polymer, a biomedical thermoplastic silicone-polycarbonate-urethane, is explored. Long-term (22 days) localized NO release is achieved by utilizing a cross-linked silicone rubber as topcoats, which can greatly reduce the amount of SNAP, NAP, and NAP disulfide leaching from the SNAP-doped CarboSil films, as measured by LC–MS. Raman spectroscopy and powder X-ray diffraction characterization of SNAP-doped CarboSil films demonstrate that a polymer–crystal composite is formed during the solvent evaporation process when SNAP exceeds its solubility in CarboSil (ca. 3.4–4.0 wt %). Further, when exceeding this solubility threshold, SNAP exists in an orthorhombic crystal form within the bulk of the polymer. The proposed mechanism of sustained NO release in SNAP-doped CarboSil is that the solubilized SNAP in the polymer matrix decomposes and releases NO, primarily in the water-rich regions near the polymer/solution interface, and the dissolved SNAP in the bulk polymeric phase becomes unsaturated, resulting in the dissolution of crystalline SNAP within the bulk of the polymer. This is a very slow process that ultimately leads to NO release at the physiological flux levels for >3 weeks. The increased stability of SNAP within CarboSil is attributed to the intermolecular hydrogen bonds between the SNAP molecules that crystallize. This crystallization also plays a key role in maintaining RSNO stability within the CarboSil polymer for >8 months at 37 °C (88.5% remains). Further, intravascular catheters fabricated with this new material are demonstrated to significantly decrease the formation of Staphylococcus aureus biofilm (a leading cause of nosocomial bloodstream infections) (in vitro) over a 7 day period, with 5 log units reduction of viable cell count on catheter surfaces. It is also shown that the NO release catheters can greatly reduce thrombus formation on the catheter surfaces during 7 h implantation in rabbit veins, when compared to the control catheters fabricated without SNAP. These results suggest that the SNAP-doped CarboSil system is a very attractive new composite material for creating long-term NO release medical devices with increased stability and biocompatibility.

Overview of Fungal Infections--The Italian Experience.

The incidence of severe fungal infections has increased worldwide and represents a serious threat, especially among immunocompromised and critically ill patients. Most common pulmonary fungal infections include aspergillosis, cryptococcosis, and Pneumocystis jiroveci pneumonia. Among nosocomial bloodstream infections, Candida spp. is the most common isolated fungus. Mortality rates up to 60% in critically ill patients with Candida infections and 90% in hematological patients with invasive aspergillosis are reported. Furthermore, fungal infections contribute to high morbidity and prolonged hospitalizations. Since standard cultural methods can show low sensitivity or provide delayed responses, new non-culture-dependent methods such as galactomannan β-D-glucan are now available. Novel antifungal compounds (e.g., amphotericin B lipid formulations, last-generation azoles, and echinocandins) have been introduced in the recent years. Nevertheless, despite new advances the appropriate use of diagnostic assays along with a thorough therapeutic management remain the key to ensure an early appropriate targeted treatment that represents the crucial factor to attain a successful approach to severe fungal infections.

Clinical characteristics and antimicrobial susceptibility of Bacillus cereus blood stream infections.

BackgroundBacillus cereus is one of the pathogens causing nosocomial bloodstream infections (BSIs). However, few reports have documented the antimicrobial susceptibility and clinical characteristics of Bacillus cereus BSI and the importance of empirical therapy. The aim of this study was to investigate the clinical characteristics and antimicrobial susceptibility of B. cereus isolates from patients with BSI and to analyze the impact of appropriate empirical therapy on the outcome of patients with B. cereus BSI.MethodsAll adult cases of bacteremia between April 2003 and March 2012 in a teaching hospital in Tokyo, Japan were reviewed retrospectively. Clinical data were collected from the patients’ medical records and charts. Antimicrobial susceptibility testing was performed by broth microdilution method. The patients with B. cereus BSI were divided into an appropriate empirical therapy group and an inappropriate empirical therapy group. The primary outcome was all-cause mortality at 4 weeks after the start of BSI. The secondary outcome was early defervescence within 2 days after starting empirical therapy.ResultsThere were 29 B. cereus bloodstream infection cases. No vancomycin, gentamicin, and imipenem-resistant isolates were found. However, 65.5 % were resistant to clindamycin and 10.3 % were resistant to levofloxacin. The main etiology was venous catheter-related (69 %). All-cause mortality at 4 weeks was not significantly different between the appropriate empirical therapy group (9 cases) and the inappropriate group (20 cases) in this study. However, early defervescence within 2 days after starting empirical therapy was significantly different (p = 0.032).ConclusionsThe BSI of B.cereus is mostly caused by venous catheter-related infections. Appropriate empirical therapy is important to achieve early clinical resolution in B. cereus BSI. Vancomycin is one of the appropriate selections of empirical therapy for B. cereus BSI.

Impact of infection control training for interns on PICU-acquired bloodstream infections in a middle-income country.

The present study aimed to determine the impact of an extended infection control training programme, which was conducted for all interns posted to the Department of Paediatrics, on the incidence of paediatric intensive care unit (PICU)-acquired bloodstream infections (BSIs) in University Malaya Medical Centre, Malaysia. The development of nosocomial BSIs during the baseline period (1 January-31 October 2008) and intervention period (1 November-31 December 2009) was monitored. During the intervention period, all paediatric interns underwent training in hand hygiene and aseptic techniques for accessing vascular catheters. A total of 25 patients had PICU-acquired BSIs during the baseline period, while 18 patients had PICU-acquired BSIs during the intervention period (i.e. infection rate of 88 per 1,000 and 41 per 1,000 admissions, respectively). The infections were related to central venous catheters (CVCs) in 22 of the 25 patients who had PICU-acquired BSIs during the baseline period and 11 of the 18 patients who had PICU-acquired BSIs during the intervention period. Thus, the incidence rates of catheter-related BSIs were 25.2 per 1,000 CVC-days and 9.3 per 1,000 CVC-days, respectively (p < 0.05). The Paediatric Risk of Standardised Mortality III score was an independent risk factor for PICU-acquired BSIs and the intervention significantly reduced this risk. The education of medical interns on infection control, a relatively low-cost intervention, resulted in a substantial reduction in the incidence of PICU-acquired BSIs.

Research Highlights

Treating and diagnosing opportunistic infections in immunosuppressed patients remains a very important aspect for all clinicians working in the field of transplantation. Candidiasis is the most common fungal infection in hospitalized patients, and for this reason, the correct diagnosis of some of the important Candida albicans or non-albicans Candida species is essential, as invasive candidiasis caused by non-albicans is associated with higher resistance rates.1,2 Mylonakis and coworkers estimated mortality rates in patients who received antifungal therapy immediately after blood cultures to be 24% while a delayed treatment starting on days 2 and 3 increased mortality rates to 37% and 41%, respectively. Candida species are traditionally diagnosed by using microscopy, histopathology, culture, plating samples on chromogenic culture media as well as identifying enzyme, metabolite, structural components of the cell wall (1,3-β-D-glucan), antibody (antimannan) or antigen (mannan). PCR testing comes with shortcomings as well and has not yet been accepted as standard of care. Blood cultures and 1,3-β-D-glucan assays have not been specific for Candida leading to potential false-positive results. Rapid Identification of Medically Important Candida Isolates Using High Resolution Melting Analysis Nemcova E, Cernochova M, Ruzicka F, Malisova B, Freiberger T, Nemec P. PloS ONE. 2015;10(2):e0116940 In this report, the authors describe a combination of real-time polymerase chain reaction (PCR) and high-resolution melting analysis (HRMA) for the rapid detection of 25 medically important Candida species. Real-time PCR followed by HRMA showed reproducible melting peaks for 21 of 25 Candida species. Misidentification occurred with C. orthopsilosis, C. metapsilosis, and C. fabianii. Clinically, the correct diagnosis of C. parapsilosis is significant as this strain is less susceptible to antifungals. Notably all C. parapsilosis were clearly distinguishable from other strains using this method. This is the widest range of Candida species ever tested and identified using the HRMA method including a large number of 143 clinical isolates covering 23 species for validation. Real-time PCR followed by HRMA appears as an efficient and simple method diagnosing most candida species. Of note, the diagnosis can be made within 6 hours based on HRMA compared to 24 to 48 hours with the biochemical methods. T2 magnetic resonance assay for the rapid diagnosis of candidemia in whole blood: a clinical trial. Mylonakis E, Clancy CJ, Ostrosky-Zeichner L, et al. Clin Infect Dis. 2015;60(6):892–899 A nanodiagnostic method using a manual application of T2 magnetic resonance (T2MR) was used in this study to diagnose 5 Candida species: C. albicans, C. tropicalis, C. Krusei, C. glabrata and C. parapsilosis. A total of 250 blood culture samples were manually supplemented with clinically relevant titres of the above Candida species and 50 samples were used as negative controls. These samples formed the contrived or control arm of the study, and they were randomly inserted into the 2264 clinical specimens to check how different titres of Candida would react to the methodology. A total of 463 samples were excluded for technical errors or invalid results. The results of the primary analysis showed an overall specificity of 99.4% per assay and 98.1% per patient. Importantly, the mean time to obtain a negative result was only 4.2 hours compared to longer than 120 hours for a blood culture (BCT). There were 31 discordant cases between T2MR and blood culture: 2 had positive BCT and negative T2MR and 29 negative BCT but positive T2MR. This can be related to either false-positive T2MR or false negative BCT. The BCT methods are known to have poor sensitivity, and clinical samples are shown to be positive in only 38% of proven invasive candidiasis.3 Therefore, it is very likely that these cases represent Candida species infections that were missed by BCT. Importantly, this new technology has a high sensitivity in identifying non-albicans Candida like C. glabrata for which this test has an overall sensitivity of 84%. This study represents the first extensive clinical trial using T2MR technology. REFERENCES Wisplinghoff H, Bischoff T, Tallent SM, et al. Nosocomial bloodstream infections in US hospitals: analysis of 24,179 cases from a prospective nationwide surveillance study. Clin Infect Dis. 2004;39(3):309–317. Chi HW, Yang YS, Shang ST, et al. Candida albicans versus non-albicans bloodstream infections: the comparison of risk factors and outcome. J Microbiol Immunol Infect. 2011;44(5):369–375. Avni T, Leibovici L, Paul M. PCR diagnosis of invasive candidiasis: systematic review and meta-analysis. J ClinMicrobiol. 2011;49(2):665–670.

Clinical importance and cost of bacteremia caused by nosocomial multi drug resistant acinetobacter baumannii

A. baumannii is an important nosocomial pathogen associated with high mortality, morbidity and medical cost. The aim of this study was to investigate risk factors for MDR A. baumannii bacteremia and also evaluate cost of hospitalization of these patients. Study was conducted in Ankara Atatürk Training and Research Hospital. Patients who were hospitalized in ICU and diagnosed for nosocomial blood stream infection (BSI) between January 2007 and December 2010 were checked retrospectively. Patients with nosocomial BSI caused by multidrug resistant A. baumannii were compared with the patients who had BSI caused by other Gram-negative microorganisms in terms of risk factors, mortality and medical costs. In multivariate analysis previous use of carbapenem, quinolone and metronidazole, and SAPS II score were found as independent risk factors. In case group; immunosupression, SAPS II score, and hospital stay until infection were independently associated with mortality in multivariate analysis. Our results suggest that the occurrence of MDR A.baumannii bacteremia was related with the usage of the wide spectrum antibiotics, and mortality rates were increased in patients that high SAPS II scores, long term hospitalization. Infection control procedures and limited antibiotic usage are very important for prevent nosocomial infections.