José Miguel Nogueira

Prognostic factors of mortality in patients with community-acquired bloodstream infection with severe sepsis and septic shock ☆,☆☆

PURPOSE The purpose of the study was to determine the independent risk factors on mortality in patients with community-acquired severe sepsis and septic shock. METHODS A single-site prospective cohort study was carried out in a medical-surgical intensive care unit in an academic tertiary care center. One hundred twelve patients with community-acquired bloodstream infection with severe sepsis and septic shock were identified. Clinical, microbiologic, and laboratory parameters were compared between hospital survivors and hospital deaths. RESULTS One-hundred twelve patients were included. The global mortality rate was 41.9%, 44.5% in septic shock and 34.4% in severe sepsis. One or more comorbidities were present in 66% of patients. The most commonly identified bloodstream pathogens were Escherichia coli (25%) and Staphylococcus aureus (21.4%). The proportion of patients receiving inadequate antimicrobial treatment was 8.9%. By univariate analysis, age, Acute Physiology and Chronic Health Evaluation II score, at least 3 organ dysfunctions, and albumin, but neither microbiologic characteristics nor site of infection, differed significantly between survivors and nonsurvivors. Acute Physiology and Chronic Health Evaluation II (odds ratio, 1.13; 95% confidence interval, 1.06-1.21) and albumin (odds ratio, 0.34; 95% confidence interval, 0.15-0.76) were independent risk factors associated with global mortality in logistic regression analysis. CONCLUSION In addition to the severity of illness, hypoalbuminemia was identified as the most important prognostic factor in community-acquired bloodstream infection with severe sepsis and septic shock.

Diagnosis of systemic candidiasis by enzyme immunoassay detection of specific antibodies to mycelial phase cell wall and cytoplasmic candidal antigens

Diagnosis of systemicCandida infections was attempted by the use of an enzyme-linked immunosorbent assay (EIA) to detect IgG antibodies towards cell wall-bound and cytoplasmic candidal antigens. Cell wall antigens were sequentially solubilized by treatment of germinated blastoconidia ofCandida albicans (ATCC 26555 strain) with β-mercaptoethanol (βME extract) and digestion with Zymolyase 20T, a β-glucanase preparation (Zymolyase extract). Protoplasts obtained after treatment with Zymolyase were osmotically lysed (cytoplasmic antigens). Sera were obtained from patients with systemic (n=28) and superficial (n=46) candidiasis. Control sera were obtained from normal healthy individuals (n=31) and from hospitalized patients at low (n=36) and at high (n=13) risk of developing systemic candidiasis yet showing no symptoms of candidal infection. Detection of antibodies in crude sera samples by EIA using all of these antigenic extracts was highly specific (98–100 %), but sensitivity of the method was low (3.5–17.8 %). However, adsorption of sera with latex microspheres coated with purifiedCandida mannan in order to selectively remove antimannan antibodies prior to EIA improved the diagnostic efficiency of this test. Improvement was particularly noticeable when the βME extract was used as antigenic preparation, yielding a sensitivity of 89.2 % and a specificity of 98.6 %.

Impact of nosocomial polymicrobial bloodstream infections on the outcome in critically ill patients

The aims of this study were to compare the clinical and microbiological characteristics from patients with polymicrobial bloodstream infections (BSI) to those from patients with monomicrobial BSI and to determine their influence on the prognosis. A prospective study was conducted on 371 nosocomial BSI in an intensive care unit (ICU). Seventy-five (20.2%) of them were polymicrobial. The mean APACHE II score at the onset of bacteremia in polymicrobial and monomicrobial BSI were 17.7 ± 6.6 and 18.9 ± 7.5, respectively (p = 0.228). Severe sepsis and septic shock were present in 68.0% and 50.6% of polymicrobial BSI and in 73.9% and 55.1% of monomicrobial BSI, respectively (p = 0.298 and p = 0.494, respectively). The length of stay and the length of stay post-infection were significantly longer in patients with polymicrobial BSI. APACHE II score at the onset of BSI, high-risk microorganisms, and septic shock were predictors of related mortality, but polymicrobial BSI and inadequate empirical antimicrobial treatment were not. Our findings suggest that the clinical and microbiological characteristics of polymicrobial BSI are not different from monomicrobial BSI, and polymicrobial BSI do not have any influence on the related mortality. However, they occurred in patients with a longer length of stay in the hospital and were associated with longer stays in the hospital after the episode of BSI.

Influence of inadequate antimicrobial therapy on prognosis in elderly patients with severe urinary tract infections

BACKGROUND Inadequate empirical antimicrobial therapy (IEAT) in intensive care unit (ICU) is associated with adverse outcomes. However, the influence of IEAT on prognosis for elderly patients with urinary tract infection (UTI) in non-ICU settings is unknown. METHODS A retrospective cross-sectional study of elderly patients admitted to a non-ICU ward in a university hospital with a primary diagnosis of UTI over a 3-year period was done. Data relating to age, sex, background comorbidities, severity of infection, bacteremia, microorganisms isolated in urine, treatment given, length of stay and prognosis were obtained using chart review. Cases were segregated according to the adequacy of empirical antimicrobial therapy. In-hospital mortality rate was the main outcome variable evaluated. RESULTS A total of 270 patients with a mean age of 83.7years were studied. Sixty-eight percent were health-care associated infections. Seventy-nine (29.3%) cases received IEAT. IEAT was associated with previous hospitalization, urinary catheter and previous antibiotic. A Gram stain of urine with a gram-positive cocci was predictive of IEAT by multivariate analysis (OR, 6.29; 95% CI, 1.05-37.49). In-hospital mortality rate was 8.9%. IEAT (OR, 3.47; 95% CI, 1.42-8.48) was an independent risk factor for mortality along with APACHE II ≥15 (OR, 3.14; 95% CI, 1.24-7.90), dementia (OR, 3.10; 95% CI, 1.19-8.07) and neoplasia (OR, 3.49; 95% CI, 1.13-10.77). IEAT was not associated with length of stay in hospital. CONCLUSION IEAT is associated with mortality in elderly patients with UTI admitted to a non-ICU ward, suggesting that improving empirical antimicrobial therapy could have a favorable impact on prognosis.

DNA amplification fingerprinting for subtyping Neisseria gonorrhoeae strains

Background and Objectives DNA amplification fingerprinting is used in most epidemiologic studies as a substitute for conventional typing methods. DNA amplification fingerprinting and conventional typing methods were compared in this epidemiologic study of Neisseria gonorrhoeae. Goal of This Study To differentiate 70 Neisseria gonorrhoeae isolates from untreated patients with urogenital gonococcal infection. Study Design Gonococcal strains were characterized by auxo-typing, serotyping, plasmid profile, antibiotic sensitivity, and DNA amplification fingerprinting. The method of unweighted pair-group average linkage was used for cluster analysis. Discriminatory power was calculated applying Simpsons index. Results Amplification of Neisseria gonorrhoeae DNA with primers OPA-03 and OPA-13 produced well-resolved patterns of 15 and 22 DNA fragments, respectively, with a discriminatory power (0.978 with OPA-13 and 0.967 with OPA-03) comparable to that obtained with auxotyping/serotyping combination (D:0.968) or with auxotype/serotype/plasmid profile combination (D:0.983). Correlation between DNA amplification fingerprinting pattern and auxotype/serotype class was not always uniform. Some strains with the same auxotype/serotype/plasmid profile were subdivided by DNA amplification fingerprinting, and vice versa. Conclusion Although auxotype/serotype class and DNA amplification fingerprinting can be used in the epidemiologic characterization of strains, DNA amplification fingerprinting offers a better discriminatory index than the separate serotyping. It is especially useful for differentiating serologically identical strains and nontypable strains. A combination of serotyping and DNA amplification fingerprinting seems to be the best way to differentiate Neisseria gonorrhoeae strains in epidemiologic studies, bringing together the most simple techniques and the best discriminatory power among isolates.

A comparative study on cell wall antigens and cell surface hydrophobicity in clinical isolates of Candida albicans.

Characterization of common cell surface-bound antigens inCandida albicans strains, particularly those expressed in the walls of mycelial cells might be useful in the diagnosis of systemic candidiasis. Hence, antigenic similarities among wall proteins and mannoproteins fromC. albicans clinical serotype A and B isolates, were studied using polyclonal (mPAbs) and monoclonal (MAb 4C12) antibodies raised against wall antigens from the mycelial form of a commonC. albicans serotype A laboratory strain (ATCC 26555). Zymolyase digestion of walls isolated from cells of the different strains studied grown at 37°C (germination conditions), released, in all cases, numerous protein and mannoprotein components larger than 100 kDa, along with a 33–34 kDa species. The pattern of major antigens exhibiting reactivity towards the mPAbs preparation was basically similar for all the serotype A and B isolates, though minor strain-specific bands were also observed. The immunodeterminant recognized by MAb 4C12 was found to be absent or present in very low amounts inC. albicans isolates other than the ATCC 26555 strain, yet high molecular weight species similar in size (e.g., 260 kDa) to the wall antigen against which MAb 4C12 was raised, were observed, particularly in wall digests from serotype A strains. Cell surface hydrophobicity, an apparently important virulence factor inC. albicans, of the cell population of each serotype B strain was lower than that of the corresponding serotype A counterparts, which is possibly due to the fact that the former strains exhibited a reduced ability to form mycelial filaments under the experimental conditions used.

Histopathology of experimental Aspergillus fumigatus keratitis

Histopathological studies in rabbits eyes, 7 and 14 days after intracorneal inoculation with 1×105Aspergillus fumigatus conidia have been performed.Similar lesions were found in both periods with fungal hyphae in the anterior third of corneal stroma, round cell infiltration from the sclero-corneal edge and in the anterior chamber and, neovascularization.No lesions were found in the Descemets membrane.Gomori silver-methenamine stain with hematoxiline-eosine counter-stain was found to be the most reliable stain to detect fungal presence in corneal stroma, and Massons trichromic stain in the study of pathological changes in ocular elements.

Effect of Bacteremia in Elderly Patients With Urinary Tract Infection

Introduction The clinical effect of bacteremia on outcomes in urinary tract infection (UTI) is still debated. This study aims to examine the clinical effect of bacteremia in elderly patients with UTI requiring hospital admission. Methods This retrospective observational study recorded the clinical features, microbiology and outcomes in a Spanish cohort of patients aged ≥65 years hospitalized for UTI in whom blood cultures were performed in the emergency department. The primary outcome of the study was in‐hospital mortality. Results Of 333 patients, with a mean age of 81.6 years, 137 (41.1%) had positive blood cultures. Escherichia coli, with 223 (66.9%) cases, was the most common microorganism isolated. Independent risk factors of bacteremia were temperature >38°C, heart rate >90 bpm and inversely both Enterococcus faecalis and Pseudomonas aeruginosa. Bacteremia was not associated with the length of stay in hospital (6.96 ± 3.50 days versus 7.33 ± 5.54 days, P = 0.456). Mortality rate was 9.3% with no significant difference between bacteremic and nonbacteremic cases (8.8% and 9.7%, respectively, P = 0.773). In‐hospital mortality analyzed by logistic regression was associated with McCabe index >2 (20.5% survival versus 66.7% death, adjusted odds ratio = 6.31, 95% CI: 2.71‐14.67; P < 0.001) but not with bacteremia (41.4% survival versus 38.7% death, adjusted odds ratio = 0.99, 95% CI: 0.43‐2.29; P = 0.992). Conclusions Our study suggests that the presence or absence of bacteremia in elderly people with UTI requiring hospitalization does not have an influence on outcomes such as in‐hospital mortality or length of stay.

Epidemiology of Severe Sepsis and Septic Shock

Sepsis is defined as the combination of pathologic infection and physiological changes known collectively as the systemic inflammatory response syndrome (Martin, 2003). This response results in physiological alterations that occur at the capillary endothelial level. In the early stages, the clinical manifestations of this process are unspecific and it is often underappreciated in clinical practice. However, early recognition of this syndrome is vital to reducing mortality in sepsis. From clinical studies sepsis can be seen as a continuum of severity that begins with an infection, followed in some cases by sepsis, severe sepsis – with organ dysfunction – and septic shock. There has been a substantial increase in the incidence of sepsis during the last decades, and it appears to be rising over time, with an increasing number of deaths occurring despite a decline in overall in-hospital mortality (Bone, 1992). Advanced age, underlying comorbidities and number of organ dysfunction are factors which are consistently associated with higher mortality in severe sepsis and septic shock. In this chapter we are going to review the definitions of sepsis syndromes, the factors that have contributed to the widening of physicians’ awareness of sepsis, severe sepsis and septic shock; the incidence of severe sepsis and septic shock; the epidemiological data of patients with severe sepsis and septic shock in the emergency departments and intensive care units; the causative microorganisms, and the changes observed over recent years.

Becton Dickinson Directigen EZ Flu A+B assay in the diagnosis of pandemic influenza A H1N1 2009 virus infection in adult patients.

To the editor: The recent emergence and spread of the pandemic influenza A H1N1 2009 virus demands the evaluation of rapid antigen assays for their ability to detect this novel subtype of influenza A virus. Data on the ability of BD Directigen EZ Flu A+B immunochromatographic (IC) assay (Beckton Dickinson and Company, Sparks, MD, USA) to detect the pandemic influenza A virus strain in fresh clinical samples have been recently published. 1 , 2 , 3 , 4 , 5 In these studies, the majority of specimens were collected from pediatric patients, and the sensitivities reported ranged from 46·8% to 76·6%. As viral shedding in the upper respiratory tract during influenza virus infection is of greater magnitude in children than in adults, the clinical utility of IC tests may indeed depend on the patient age. 6 We wish to report on our experience regarding the diagnostic and analytical performance characteristics of the Directigen EZ Flu A+B in a cohort of adults (≥18 years old) presenting with an influenza‐like syndrome at a tertiary Spanish hospital (Peset Aleixandre, Valencia Spain). A total 274 nasopharyngeal swabs from unique patients (median age of 50 years, range 18–97 years; 145 women and 129 men) and collected between July and September 2009 were included in the study. The specimens were obtained within 72 hours after the onset of symptoms by means of flexible nasopharyngeal nylon flocked swabs, placed in 3 ml of transport medium (Universal transport medium; Beckton Dickinson) and delivered to the Microbiology laboratory within 1 hours of collection. The specimens were vortexed and tested by the IC assay following the instructions of the manufacturer. 7 Samples were assayed by RT‐PCR within 24 hours after reception. Total RNA was extracted by the MagNApure extraction kit in the MagNA Pure robot (Roche Diagnostics, Basel, Switzerland), and RT‐PCR was performed by use of the Realtime Ready Influenza A/H1N1 Detection Set on the LightCycler® 2.0 instrument (Roche Diagnostics). 8 , 9 The overall positive rate for novel influenza A virus RNA as determined by real‐time PCR was 15·3%. Forty‐two specimens tested positive by RT‐PCR, of which 18 gave a positive IC result. The remaining 232 specimens tested negative by RT‐PCR. All these specimens gave a negative result in the IC assay. The overall agreement between the two assays was 91·2% (250/274), and the sensitivity, specificity, positive predictive value, and negative predictive value (adjusted to the prevalence in our cohort) were of 42·8%, 100%, 100%, and 79·8%, respectively. Cycle threshold (Ct) values for samples testing positive by the IC assay (median, 24·1, range, 20·5–33·6) were significantly lower (P = 0·001, by the Mann–Whitney test) than those for specimens yielding a negative result (median, 31·5, range, 30·2–34·5). To determine the analytical sensitivity of the IC assay, a local influenza strain (A/Valencia/1/2009H1N1v) isolated in Mardin Darby Canine Kidney cells was used. The viral stock (50% tissue culture infectious dose‐TCID50‐/ml of log10 7·0) was serially diluted in viral transport medium and tested in duplicate by IC. The limit of detection of the BD Directigen assay was approximately log10 4·5 TCID50/ml, which is in keeping with previous estimations. 3 , 10 In summary, the sensitivity of the Directigen EZ Flu A+B assay for the diagnosis of pandemic influenza A virus infection is clearly suboptimal and appears to be lower than that reported in studies conducted in either pediatric or mixed children and adult cohorts. Thus, molecular testing should be mandatory when a negative IC result is obtained, particularly in adult patients with a high pretest probability of infection. Nevertheless, given the specificity of the assay, a positive IC result may be safely used in making decisions regarding the instauration of antiviral treatments or implementation of infection control measures.