Predictors of mortality in Acinetobacter baumannii bacteremia.

This study retrospectively investigated 149 episodes of Acinetobacter baumannii bacteremia which occurred during a 41-month period from September 1997 to January 2001. Bacteremia was nosocomial in 139 (93%) of the episodes and community-acquired in 10 (7%). Thirty three deaths (22.1%) were attributed to these episodes of A. baumannii bacteremia. The mean age of survivors was younger than that of patients who died of bacteremia (60.4 +/- 19.9 vs 67.1 +/- 17.4) but this result was not significant on univariate analysis (p=0.084). Previous intensive care unit stay was longer among survivors than among patients who died of bacteremia (9.5 vs 18 days, p=0.048). Factors associated with mortality included immunosuppression (p=0.019), shock (p=0.002), recent surgery (p=0.008), invasive procedures such as central venous catheterization (p=0.002), urinary catheterization (p=0.012), placement of a nasogastric tube (p<0.001), pulmonary catheterization (p=0.015), and mechanical ventilation (p=0.035). The number of underlying conditions (p=0.015) and invasive procedures (p<0.001) were positively correlated with mortality. Mortality was significantly associated with lower platelet count (p=0.001) and lower serum albumin concentration (p=0.005). Patients with catheter-related bacteremia had a high survival rate (96.2%), while survival rate was low in patients with infection originating from the respiratory tract (60.8%). Susceptibility testing by agar dilution test indicated that imipenem was the most effective antibiotic, followed by cefepime and ciprofloxacin. The mortality rate was lower in patients who received 1 or more antibiotics to which the isolates were susceptible, but this difference was not significant (p=0.197). On multivariate analysis, factors that independently correlated with mortality were increased age (p=0.003), immunosuppressive status (p=0.001), recent surgery (p=0.002), acute respiratory failure (p=0.004), acute renal failure (p=0.009) and septic shock (p<0.001). These findings highlight the importance of a treatment strategy based on risk stratification among patients with A. baumannii bacteremia.     

Risk factors and mortality of healthcare-associated and community-acquired Staphylococcus aureus bacteraemia

Staphylococcus aureus bacteraemia (SAB) is a leading cause of mortality and morbidity in both nosocomial and community settings. The objective of the study is to explore epidemiological characteristics and predisposing risk factors associated with healthcare-associated (HCA) and community-acquired (CA) SAB, and to evaluate any differences in mortality and efficacy of initial antimicrobial therapy on treatment outcome. We conducted a two-part analysis. First, a triple case-control study in which groups of HCA SAB with onset ≥ 48 h after hospital admission (HCA ≥ 48 h), HCA SAB with onset <48 h of hospital admission (HCA <48 h), and CA SAB were compared with controls. Second, a cohort study including all patients with SAB was performed to identify factors associated with in-hospital mortality. SAB was diagnosed in 165 patients over the study period (January 2007 to December 2007). Five variables were independently associated with HCA ≥ 48 h SAB: presence of central venous catheter, solid tumour, chronic renal failure, previous hospitalization and previous antibiotic therapy. Significant risk factors for HCA <48 h SAB were: Charlson Comorbidity Index ≥ 3, previous hospitalization, living in long-term care facilities and corticosteroid therapy. Factors independently associated with CA SAB were: diabetes mellitus, HIV infection and chronic live disease. Patients with HCA <48 h SAB were significantly more likely to receive initial inadequate antimicrobial treatment than patients with CA or HCA ≥ 48 h SAB (44.8% versus 33.3% and 31.5%, respectively). Logistic-regression analysis identified three variables as independent predictors of mortality: presentation with septic shock, infection with methicillin-resistant S. aureus, and initial inadequate antimicrobial treatment. More than half of patients with SAB have MRSA strains and presentation with septic shock, and inappropriate empirical therapy was associated with increased mortality.     

Seven-Year Study of Bacteraemic Pneumonia in a Single Institution

 In order to enhance current knowledge of nosocomial and community-acquired bacteraemic pneumonia in a single tertiary hospital in Israel, a 7-year study was conducted. Using a computerised database, all patients who had bacteraemic pneumonia from March 1988 to August 1995 were studied. During the study period, pneumonia was the source of bacteraemia in 319 of 4,548 (7%) episodes, occurring in 295 patients; 211 (66%) episodes were community-acquired and 108 (34%) were nosocomial. The microoroganisms isolated most frequently from patients with community-acquired bacteraemic pneumonia were Streptococcus pneumoniae (46%), Staphylococcus aureus (10%) and Haemophilus influenzae (8%); while Pseudomonas spp. (17%), Klebsiella spp. (11%) and Staphylococcus aureus (10%) were isolated most often from the patients with nosocomial bacteraemic pneumonia. The median age of patients was 68 years (range, 0.003–100). The overall mortality was 34%. No significant difference was found between the mortality rates of patients with community-acquired (31%) and nosocomial (40%) bacteraemic pneumonia (P=0.1). Multivariate analysis showed that hypothermia, respiratory failure, impaired consciousness, tracheal intubation, Staphylococcus aureus aetiology, septic shock, inappropriate empiric antibiotic treatment and age significantly increased mortality.     

Bacterial pneumonia in HIV-infected patients

This case-control study assessed risk factors and prognostic indicators of 350 episodes of bacterial pneumonia in 285 HIV-infected patients. On univariate analysis, intravenous drug abuse (p<0.001), regular cigarette smoking (p<0.001), cirrhosis (p=0.04), and history of a previous episode of pneumonia (p=0.04), were risk factors for community-acquired episodes of bacterial pneumonia, whereas length of hospitalization (p=0.01) was a risk factor only for nosocomial bacterial pneumonia. The small amount of circulating T CD4+ cells, (<100/mmc) was a risk factor in both groups of pneumonia (p<0.05). Stepwise logistic regression analysis revealed that IVDA in community-acquired episodes and low levels of circulating T CD4+ cells, both in community-acquired and hospital-acquired episodes, were independent risk factors for the development of bacterial pneumonia. The case-fatality rate observed in our study was 27%. On stepwise logistic regression analysis, T CD4+ cell counts >100/mmc (p<0.02), neutropenia (p=0.04), PO2 arterial level <70 mmHg (p=0.01), and Karnofsky score <50 (p=0.04) were independent indicators of mortality. According to a personally developed prognostic score, 211 episodes of pneumonia (60%) were classified as mild, 63 (18%) as moderate, and 76 (22%) as severe. Clinicians must carefully evaluate those variables that can influence the prognosis of bacterial pneumonia to make early identification of affected patients and to promptly establish the most appropriate therapeutic strategy in each case.     

Community-acquired versus nosocomial Klebsiella pneumoniae bacteremia: clinical features, treatment outcomes, and clinical implication of antimicrobial resistance

We conducted this study to compare clinical features, outcomes, and clinical implication of antimicrobial resistance in Klebsiella pneumoniae bacteremia acquired as community vs. nosocomial infection. A total of 377 patients with K. pneumoniae bacteremia (191 community-acquired and 186 nosocomial) were retrospectively analyzed. Neoplastic diseases (hematologic malignancy and solid tumor, 56%) were the most commonly associated conditions in patients with nosocomial bacteremia, whereas chronic liver disease (35%) and diabetes mellitus (20%) were the most commonly associated conditions in patients with community-acquired bacteremia. Bacteremic liver abscess occurred almost exclusively in patients with community-acquired infection. The overall 30-day mortality was 24% (91/377), and the mortality of nosocomial bacteremia was significantly higher than that of community-acquired bacteremia (32% vs. 16%, p<0.001). Of all community-acquired and nosocomial isolates, 4% and 33%, respectively, were extended-spectrum cephalosporin (ESC)-resistant, and 4% and 21%, respectively, were ciprofloxacin (CIP)-resistant. In nosocomial infections, prior uses of ESC and CIP were found to be independent risk factors for ESC and CIP resistance, respectively. Significant differences were identified between community-acquired and nosocomial K. pneumoniae bacteremia, and the mortality of nosocomial infections was more than twice than that of community-acquired infections. Antimicrobial resistance was a widespread nosocomial problem and also identified in community-acquired infections.     

Formal infectious diseases consultation is associated with decreased mortality in Staphylococcus aureus bacteraemia

To determine the impact of infectious diseases consultation (IDC) in Staphylococcus aureus bacteraemia. All MRSA bacteraemia and a random subset of MSSA bacteraemia were retrospectively analysed. Out of 599 SAB episodes, 162 (27%) were followed by an IDC. Patients with IDC were younger and more frequently intravenous drug users, but fewer resided in a long-term care facility or were indigenous. Hospital length of stay was longer (29.5 vs 17?days, p?相似文献   

Staphylococcus aureus bacteraemia in Iceland, 1995–2008: changing incidence and mortality

Little is known about temporal changes in the epidemiology of Staphylococcus aureus bacteraemia. The objective of the present study was to analyse changes in the incidence and mortality of adult S. aureus bacteraemia in Iceland. Individuals 18 years or older with a positive blood culture for S. aureus between 1 January 1995 and 31 December 2008 were identified, with the participation of all clinical microbiological laboratories performing blood cultures in Iceland. Infections were categorized as nosocomial, healthcare-associated or community-acquired. National population statistics and dates of death were retrieved from the National Registry. During the study period, 692 individuals from 19 institutions had 721 distinct episodes of S. aureus bacteraemia. The incidence rose from 22.7 to 28.9 per 100 000 per year during the period (p 0.012). Nosocomial infections comprised 46.3% of cases, 14.6% were healthcare-associated, and 39.1% were community-acquired. The proportion of nosocomial infections decreased during the period (p <0.001), whereas an increase was seen in the proportion of community-acquired infections (p <0.001). All-cause 30-day mortality decreased from 25.0% to 8.1% (p 0.001) and 1-year mortality decreased from 37.0% to 27.9% (p 0.061) between the periods 1995–1996 and 2007–2008. Four cases of bacteraemia caused by methicillin-resistant S. aureus were seen (0.6%), none of which was fatal. In conclusion, there was a significant increase in the incidence of S. aureus bacteraemia in Iceland between 1995 and 2008. Concomitantly, there was a significant reduction in mortality, towards one of the lowest reported. Further studies are needed to understand the basis for these changes.     

Community-acquired pneumonia in patients with bacterial meningitis: a prospective nationwide cohort study

ObjectivePneumonia is considered a focus of infection in patients presenting with community-acquired bacterial meningitis but the impact on disease course is unclear. The aim was to study presenting characteristics, clinical course and outcome of meningitis patients with co-existing pneumonia on admission.MethodsWe evaluated adult patients with community-acquired bacterial meningitis with pneumonia on admission in a nationwide, prospective cohort performed from March 2006 to June 2017. We performed logistic regression analysis to identify clinical characteristics predictive of pneumonia on admission, and to quantify the effect of pneumonia on outcome.ResultsPneumonia was diagnosed on admission in 315 of 1852 (17%) bacterial meningitis episodes and confirmed by chest X-ray in 256 of 308 (83%) episodes. Streptococcus pneumoniae was the causative organism in 256 of 315 episodes (81%). Pneumonia on admission was associated with advanced age (OR 1.03 per year increase, 95% CI 1.02–1.04, p < 0.001), alcoholism (OR 1.96, 95% CI 1.23–3.14, p 0.004), cancer (OR 1.54, 95% CI 1.12–2.13, p 0.008), absence of otitis or sinusitis (OR 0.44, 95% CI 0.32–0.59, p < 0.001) and S. pneumoniae (OR 2.14, 95% CI 1.55–2.95, p < 0.001) in the multivariate analysis. An unfavourable outcome defined as a score of 1–4 on the Glasgow Outcome Scale was observed in 172 (55%) episodes and 87 patients (28%) died. Pneumonia on admission was independently associated with unfavourable outcome and mortality in the multivariate analysis (OR 1.48, 95% CI 1.12–1.96; p 0.005).ConclusionPneumonia on admission in bacterial meningitis is a frequent coexisting infection and is independently associated with unfavourable outcome and mortality.     

Epidemiology and clinical presentation of community-acquired Staphylococcus aureus bacteraemia in children under 5 years of age admitted to the Manhiça District Hospital,Mozambique, 2001–2019

Staphylococcus aureus bacteraemia (SAB) is one of the most common bloodstream infections globally. Data on the burden and epidemiology of community-acquired SAB in low-income countries are scarce but needed to define preventive and management strategies. Blood samples were collected from children < 5 years of age with fever or severe disease admitted to the Manhiça District Hospital for bacterial isolation, including S. aureus. Between 2001 and 2019, 7.6% (3,197/41,891) of children had bacteraemia, of which 12.3% corresponded to SAB. The overall incidence of SAB was 56.1 episodes/100,000 children-years at risk (CYAR), being highest among neonates (589.8 episodes/100,000 CYAR). SAB declined significantly between 2001 and 2019 (322.1 to 12.5 episodes/100,000 CYAR). In-hospital mortality by SAB was 9.3% (31/332), and significantly associated with infections by multidrug-resistant (MDR) strains (14.7%, 11/75 vs. 6.9%, 14/204 among non-MDR, p = 0.043) and methicillin-resistant S. aureus (33.3%, 5/15 vs. 7.6%, 20/264 among methicillin-susceptible S. aureus, p = 0.006). Despite the declining rates of SAB, this disease remains an important cause of death among children admitted to MDH, possibly in relation to the resistance to the first line of empirical treatment in use in our setting, suggesting an urgent need to review current policy recommendations.

     

Comparison of mortality between nosocomial and community-acquired febrile neutropenia patients treated initially with cefazolin plus tobramycin: retrospective chart review

Cefazolin plus tobramycin have been determined to be effective for community-acquired FN, but have not been evaluated in the treatment of nosocomial FN. This study compared the incidence of mortality from 2002 to 2004 with 2008 to 2009 in patients with nosocomial FN treated with cefazolin plus tobramycin and compared characteristics of patients with nosocomially acquired FN to community acquired FN. A retrospective chart review of 45 nosocomial FN episodes from 2008 to 2009, and 54 episodes from 2002 to 2004 treated with cefazolin plus tobramycin was conducted. Data on the community acquired FN episodes was obtained from our previous research. Nosocomial FN mortality increased from 4% in 2002–2004 to 13% in 2008–2009 (p = 0.08). The nosocomial cohort was at higher risk of medical complications and mortality than the community-acquired cohort based on several variables (neutrophil nadir, duration of neutropenia and fever, hematological malignancy, MASCC and Talcott score; p < 0.05). As a result, the nosocomial cohort was treated with longer courses of antibiotic therapy (14 days vs 7 days; p < 0.0001) and were more likely to require broader spectrum antibiotics (64 out of 99 vs 34 out of 96; p < 0.0001). There was an observed increased risk of mortality from 2002 to 2004 compared with 2008 to 2009 in patients treated with cefazolin plus tobramycin for nosocomial FN, this was notable despite not attaining statistical significance. Therefore, this regimen is not appropriate for nosocomial FN.     

Impact of antimicrobial treatment duration on outcome of Staphylococcus aureus bacteraemia: a cohort study

ObjectivesTo assess the outcome of Staphylococcus aureus bacteraemia (SAB) according to factors associated with necessity for longer treatment in conjunction with the duration of treatment.MethodsWe prospectively collected the data of patients with SAB consecutively during 12 to 39 months from 11 hospitals. If multiple episodes of SAB occurred in one patient, only the first episode was enrolled. Factors associated with necessity for longer treatment were defined as follows: persistent bacteraemia, metastatic infection, prosthesis and endocarditis. If any of the factors were present, then the case was defined as longer antibiotic treatment warranted (LW) group; those without any factors were defined as shorter antibiotic treatment sufficient (SS) group. Poor outcome was defined as a composite of 90-day mortality or 30-day recurrence. Duration of antibiotic administration was classified as <14 or ≥14 days in the SS group and <28 or ≥28 days in the LW group.ResultsAmong 2098 cases, the outcome was analysed in 1866 cases, of which 591 showed poor outcome. The SS group accounted for 964 cases and the LW group for 852. On multivariate analysis, age over 65 years, pneumonia, higher Sequential Organ Failure Assessment (SOFA) score and chronic liver diseases were risk factors for poor outcome. Administration of antibiotics less than the recommendation was associated with poor outcome, but this significance was observed only in the LW group (adjusted odds ratio = 1.68; 95% confidence interval, 1.00–2.83; p 0.05).ConclusionsInappropriately short antibiotic treatment was associated with poor outcome in the LW group. Vigilant evaluation for risk factors to determine the duration of treatment may improve the outcome among patients with SAB.     

Clinical characteristics and prognostic factors of patients with Stenotrophomonas maltophilia bacteremia.

Stenotrophomonas maltophilia is an important nosocomial pathogen with intrinsic multi-drug resistance. This retrospective study reviewed 84 episodes of S. maltophilia bacteremia over a 4-year period from July 1999 to September 2003. Stenotrophomonas maltophilia bacteremia was hospital-acquired in 64 patients (76%), and developed after prolonged hospitalization in 48 (57%). Seventy patients (83%) had a central venous catheter (CVC), 64 (76%) had prior antibiotic therapy, 55 (65%) had underlying malignancy, and 43 (51%) were receiving immunosuppressive therapy. Twenty seven percent of the episodes of bacteremia had polymicrobial isolates. The overall and bacteremia-related mortality rates were 44% and 33%, respectively. Forty six percent of the bacteremia-related mortality occurred within 3 days after onset of symptoms. The most common sources of bacteremia were respiratory tract (33%) and CVC (31%), while the source of the bacteremia was unknown in 26% of episodes. The most effective antibiotics in vitro were trimethoprim-sulfamethoxazole, ciprofloxacin, chloramphenicol, and ceftazidime; however, a trend of increasing drug resistance in these agents was identified over the study period. On univariate analysis, nosocomial bacteremia, long-lasting neutropnenia (>10 days), bacteremia originating from the respiratory tract, shock, low serum albumin level (<3 g/dL), and thrombocytopenia (platelet count <100,000/mm3) were significantly related to mortality (p<0.05). Among these variables, shock and thrombocytopenia were independent factors associated with mortality. In contrast, patients with CVC-related bacteremia had a lower mortality rate (odds ratio, 0.04; p<0.001). Patients treated with appropriate antibiotics had a lower mortality rate, but this difference was not significant (p=0.477). In S. maltophilia bacteremia, careful evaluation of CVC was important for identifying the source of bacteremia and predicting prognosis. The source of bacteremia and condition of patients at presentation were the major factors influencing prognosis.     

Healthcare-associated,community-acquired and hospital-acquired bacteraemic urinary tract infections in hospitalized patients: a prospective multicentre cohort study in the era of antimicrobial resistance

The clinical and microbiological characteristics of community-onset healthcare-associated (HCA) bacteraemia of urinary source are not well defined. We conducted a prospective cohort study at eight tertiary-care hospitals in Spain, from October 2010 to June 2011. All consecutive adult patients hospitalized with bacteraemic urinary tract infection (BUTI) were included. HCA-BUTI episodes were compared with community-acquired (CA) and hospital-acquired (HA) BUTI. A logistic regression analysis was performed to identify 30-day mortality risk factors. We included 667 episodes of BUTI (246 HCA, 279 CA and 142 HA). Differences between HCA-BUTI and CA-BUTI were female gender (40% vs 69%, p <0.001), McCabe score II–III (48% vs 14%, p <0.001), Pitt score ≥2 (40% vs 31%, p 0.03), isolation of extended spectrum β-lactamase-producing Enterobacteriaciae (13% vs 5%, p <0.001), median hospital stay (9 vs 7 days, p 0.03), inappropriate empirical antimicrobial therapy (21% vs 13%, p 0.02) and mortality (11.4% vs 3.9%, p 0.001). Pseudomonas aeruginosa was more frequently isolated in HA-BUTI (16%) than in HCA-BUTI (4%, p <0.001). Independent factors for mortality were age (OR 1.04; 95% CI 1.01–1.07), McCabe score II–III (OR 3.2; 95% CI 1.8–5.5), Pitt score ≥ 2 (OR 3.2 (1.8–5.5) and HA-BUTI OR 3.4 (1.2–9.0)). Patients with HCA-BUTI are a specific group with significant clinical and microbiological differences from patients with CA-BUTI, and some similarities with patients with HA-BUTI. Mortality was associated with patient condition, the severity of infection and hospital acquisition.     

Adult bacterial meningitis: aetiology, penicillin susceptibility, risk factors, prognostic factors and guidelines for empirical antibiotic treatment

Episodes of adult bacterial meningitis (ABM) at a Danish hospital in 1991-2000 were identified from the databases of the Department of Clinical Microbiology, and compared with data from the Danish National Patient Register and the Danish National Notification System. Reduced penicillin susceptibility occurred in 21 (23%) of 92 cases of known aetiology, compared to an estimated 6% in nationally notified cases (p < 0.001). Ceftriaxone plus penicillin as empirical treatment was appropriate in 97% of ABM cases in the study population, and in 99.6% of nationally notified cases. The notification rate was 75% for penicillin-susceptible episodes, and 24% for penicillin-non-susceptible episodes (p < 0.001). Cases involving staphylococci, Pseudomonas spp. and Enterobacteriaceae were under-reported. Among 51 ABM cases with no identified risk factors, nine of 11 cases with penicillin-non-susceptible bacteria were community-acquired. Severe sequelae correlated independently with age, penicillin non-susceptibility, mechanical ventilation and non-transferral to a tertiary hospital (p < 0.05; logistic regression). Other factors that correlated with severe sequelae by univariate analysis only were inappropriate clinical handling, abnormal consciousness, convulsions and nosocomial infection. Overall, the data indicated that neither age alone, community-acquired infection nor absence of identified risk factors can predict susceptibility to penicillin accurately. Recommendations for empirical antibiotic treatment for ABM should not be based exclusively on clinical notification systems with possible unbalanced under-reporting.     

Impact of pre-hospital antibiotic use on community-acquired pneumonia

Information on the influence of pre-hospital antibiotic treatment on the causative organisms, clinical features and outcomes of patients with community-acquired pneumonia (CAP) remains scarce. We performed an observational study of a prospective cohort of non-immunosuppressed adults hospitalized with CAP between 2003 and 2012. Patients were divided into two groups: those who had received pre-hospital antibiotic treatment for the same episode of CAP and those who had not. A propensity score was used to match patients. Of 2179 consecutive episodes of CAP, 376 (17.3%) occurred in patients who had received pre-hospital antibiotic treatment. After propensity score matching, Legionella pneumophila was more frequently identified in patients with pre-hospital antibiotic treatment, while Streptococcus pneumoniae was less common (p <0.001 and p <0.001, respectively). Bacteraemia was less frequent in pre-treated patients (p 0.01). The frequency of positive sputum culture and the sensitivity and specificity of the pneumococcal urinary antigen test for diagnosing pneumococcal pneumonia were similar in the two groups. Patients with pre-hospital antibiotic treatment were less likely to present fever (p 0.02) or leucocytosis (p 0.001). Conversely, chest X-ray cavitation was more frequent in these patients (p 0.04). No significant differences were found in the frequency of patients classified into high-risk Pneumonia Severity Index classes, in intensive care unit admission, or in 30-day mortality between the groups. In conclusion, L. pneumophila occurrence was nearly three times higher in patients who received pre-hospital antibiotics. After a propensity-adjusted analysis, no significant differences were found in prognosis between study groups. Pre-hospital antibiotic use should be considered when choosing aetiological diagnostic tests and empirical antibiotic therapy in patients with CAP.     

Efficacy of adjunctive nebulized colistin in critically ill patients with nosocomial carbapenem-resistant Gram-negative bacterial pneumonia: a multi-centre observational study

ObjectivesTo investigate the association between adjunctive nebulized colistin and treatment outcomes in critically ill patients with nosocomial carbapenem-resistant Gram-negative bacterial (CR-GNB) pneumonia.MethodsThis retrospective, multi-centre, cohort study included individuals admitted to the intensive care unit with nosocomial pneumonia caused by colistin-susceptible CR-GNB. Enrolled patients were divided into groups with/without nebulized colistin as adjunct to at least one effective intravenous antibiotic. Propensity score matching was performed in the original cohort (model 1) and a time-window bias-adjusted cohort (model 2). The association between adjunctive nebulized colistin and treatment outcomes was analysed.ResultsIn total, 181 and 326 patients treated with and without nebulized colistin, respectively, were enrolled for analysis. The day 14 clinical failure rate and mortality rate were 41.4% (75/181) versus 46% (150/326), and 14.9% (27/181) versus 21.8% (71/326), respectively. In the propensity score-matching analysis, patients with nebulized colistin had lower day 14 clinical failure rates (model 1: 41% (68/166) versus 54.2% (90/166), p 0.016; model 2: 35.3% (41/116) versus 56.9% (66/116), p 0.001). On multivariate analysis, nebulized colistin was an independent factor associated with fewer day 14 clinical failures (model 1: adjusted odds ratio (aOR) 0.59, 95% CI 0.37–0.92; model 2: aOR 0.37, 95% CI 0.21–0.65). Nebulized colistin was not associated independently with a lower 14-day mortality rate in the time-dependent analysis in both models 1 and 2.ConclusionsAdjunctive nebulized colistin was associated with lower day 14 clinical failure rate, but not lower 14-day mortality rate, in critically ill patients with nosocomial pneumonia caused by colistin-susceptible CR-GNB.     

Nosocomial and Community-Acquired Spontaneous Bacterial Peritonitis: Comparative Microbiology and Therapeutic Implications

In order to compare the microbiological characteristics of nosocomial and community-acquired episodes of bacterial peritonitis, 95 consecutive, spontaneous episodes were reviewed. Seventy of these episodes were bacteriologically documented. Fifty-three (55.8%) episodes were nosocomial and 42 (44.2%) were community acquired. A total of 78 pathogens were isolated, including 40 gram-positive cocci (34 streptococci, 6 Staphylococcus aureus), 35 gram-negative bacilli (including 23 Escherichia coli), 2 gram-positive bacilli and 1 yeast. Streptococci were found more frequently in community-acquired episodes (53.8%) than in nosocomial episodes (33.3%). Gram-negative bacilli were significantly more frequent in nosocomial episodes than in community-acquired episodes (56.4% vs. 33.3%, P<0.05). Nosocomial isolates were significantly more resistant to amoxicillin-clavulanic acid (48.7% vs. 18.4%, P<0.01) and cefotaxime (33.3% vs. 13.2%, P<0.05) than community-acquired isolates, but no difference was detected regarding resistance to ciprofloxacin. The results indicate that the empirical treatment of spontaneous bacterial peritonitis should differ for nosocomial and community-acquired cases. Electronic Publication     

Online-Only Abstract: This article is available online at wileyonlinelibrary.com

Information on the influence of pre-hospital antibiotic treatment on the causative organisms, clinical features and outcomes of patients with community-acquired pneumonia (CAP) remains scarce. We performed an observational study of a prospective cohort of non-immunosuppressed adults hospitalized with CAP between 2003 and 2012. Patients were divided into two groups: those who had received pre-hospital antibiotic treatment for the same episode of CAP and those who had not. A propensity score was used to match patients. Of 2179 consecutive episodes of CAP, 376 (17.3%) occurred in patients who had received pre-hospital antibiotic treatment. After propensity score matching, Legionella pneumophila was more frequently identified in patients with pre-hospital antibiotic treatment, while Streptococcus pneumoniae was less common (p <0.001 and p <0.001, respectively). Bacteraemia was less frequent in pre-treated patients (p 0.01). The frequency of positive sputum culture and the sensitivity and specificity of the pneumococcal urinary antigen test for diagnosing pneumococcal pneumonia were similar in the two groups. Patients with pre-hospital antibiotic treatment were less likely to present fever (p 0.02) or leucocytosis (p 0.001). Conversely, chest X-ray cavitation was more frequent in these patients (p 0.04). No significant differences were found in the frequency of patients classified into high-risk Pneumonia Severity Index classes, in intensive care unit admission, or in 30-day mortality between the groups. In conclusion, L. pneumophila occurrence was nearly three times higher in patients who received pre-hospital antibiotics. After a propensity-adjusted analysis, no significant differences were found in prognosis between study groups. Pre-hospital antibiotic use should be considered when choosing aetiological diagnostic tests and empirical antibiotic therapy in patients with CAP.     

Serum capacity to neutralize superantigens does not affect the outcome of Staphylococcus aureus bacteremia

Staphylococcal superantigens (SAg) could play an important role in sepsis by activating numerous T cells. We investigated whether serum capacity to neutralize SAgs can be a prognostic factor in Staphylococcus aureus bacteremia (SAB). In a university hospital, 105 consecutive SAB patients were enrolled during a 12-month period. The earliest serum samples prior to SAB onset were stored for a later T cell proliferation assay. Multiplex polymerase chain reaction (PCR) for 19 SAg genes was performed for S. aureus blood isolates. To determine the serum capacity to neutralize SAgs, T cell proliferation by the culture supernatant of each S. aureus isolate was measured in the presence and absence of the corresponding patient’s serum. Twenty-six (24.8%) patients died within 4?weeks from SAB onset. Vascular catheter-related infection was associated with survival for ≥4?weeks. Unknown primary focus, Simplified Acute Physiology Score-II (SAPS-II), and specific SAg genes (tst, sec, sel, or sep) were associated with the 4-week mortality. No variables related to T cell proliferation assay showed statistical significance. In the multivariate analysis, SAPS-II ≥33 and tst were independently associated with the 4-week mortality. Serum capacity to neutralize SAg does not significantly affect SAB outcome. SAPS-II ≥33 and tst are independent predictors of the 4-week mortality.     

Prospective evaluation of blood cultures in a Turkish university hospital: epidemiology, microbiology and patient outcome

The aims of this prospective study were to: (1) determine the rate of blood culture contamination; (2) describe and compare the epidemiologic, clinical and microbiological characteristics of hospital- and community-acquired bloodstream infections; and (3) determine the mortality resulting from bloodstream infections. The rate of true bacteremia was 12.1%, and 10.7% of cultures were contaminated. Of the 567 episodes of bloodstream infection, 73.4% were hospital-acquired, and 26.6% were community-acquired. The most commonly isolated microorganisms were staphylococci (44%, methicillin resistant 69.4%), enterococci (15%) and Escherichia coli (12.5%) in hospital-acquired episodes, and Brucella spp. (21.9%), E. coli (19.2%) and Staphylococcus aureus (14.6%, methicillin resistant 9.1%) in community-acquired episodes. While the overall mortality rate was 25.4%, death attributable to bloodstream infections was 16.6% in hospital-acquired episodes and 13.9% in community-acquired episodes. The highest mortality occurred in patients with bacteremia due to Pseudomonas aeruginosa (37.5%) in hospital-acquired episodes, and in patients with bacteremia due to Streptococcus pneumoniae (50%) in community-acquired episodes. Underlying diseases, severity of illness, presence of bladder catheter, previous use of antibiotics, tracheal intubation and adequacy of treatment were found to be significantly associated with death.