Community-acquired polymicrobial pneumonia in the intensive care unit: aetiology and prognosis

Introduction: The frequency and clinical significance of polymicrobial aetiology in community-acquired pneumonia (CAP) patients admitted to the ICU have been poorly studied. The aim of the present study was to describe the prevalence, clinical characteristics and outcomes of severe CAP of polymicrobial aetiology in patients admitted to the ICU. Methods: The prospective observational study included 362 consecutive adult patients with CAP admitted to the ICU within 24 hours of presentation; 196 (54%) patients had an established aetiology. Results: Polymicrobial infection was present in 39 (11%) cases (20% of those with defined aetiology): 33 cases with two pathogens, and six cases with three pathogens. The most frequently identified pathogens in polymicrobial infections were Streptococcus pneumoniae (n = 28, 72%), respiratory viruses (n = 15, 39%) and Pseudomonas aeruginosa (n = 8, 21%). Chronic respiratory disease and acute respiratory distress syndrome criteria were independent predictors of polymicrobial aetiology. Inappropriate initial antimicrobial treatment was more frequent in the polymicrobial aetiology group compared with the monomicrobial aetiology group (39% vs. 10%, P < 0.001), and was an independent predictor of hospital mortality (adjusted odds ratio = 10.79, 95% confidence interval = 3.97 to 29.30; P < 0.001). The trend for higher hospital mortality of the polymicrobial aetiology group compared with the monomicrobial aetiology group (n = 8, 21% versus n = 17, 11%), however, was not significantly different (P = 0.10). Conclusions: Polymicrobial pneumonia occurs frequently in patients admitted to the ICU. This is a risk factor for inappropriate initial antimicrobial treatment, which in turn independently predicts hospital mortality

Community-Acquired Pneumonia Due to Multidrug- and Non–Multidrug-Resistant Pseudomonas aeruginosa

Background: Pseudomonas aeruginosa is not a frequent pathogen in community-acquired pneumonia (CAP). However, in patients with severe CAP, P aeruginosa can be the etiology in 1.8% to 8.3% of patients, with a case-fatality rate of 50% to 100%. We describe the prevalence, clinical characteristics, outcomes, and risk factors associated with CAP resulting from multidrug-resistant (MDR) and non-MDR P aeruginosa. Methods: Prospective observational study of 2,023 consecutive adult patients with CAP with definitive etiology. Results: P aeruginosa was found in 77 (4%) of the 2,023 cases with microbial etiology. In 22 (32%) of the 68 cases of P aeruginosa with antibiogram data, the isolates were MDR. Inappropriate therapy was present in 49 (64%) cases of P aeruginosa CAP, including 17/22 (77%) cases of MDR P aeruginosa CAP. Male sex, chronic respiratory disease, C-reactive protein <12.35 mg/dL, and pneumonia severity index risk class IV to V were independently associated with P aeruginosa CAP. Prior antibiotic treatment was more frequent in MDR P aeruginosa CAP compared with non-MDR P aeruginosa (58% vs 29%, P = .029), and was the only risk factor associated with CAP resulting from MDR P aeruginosa. In the multivariate analysis, age ≥65 years, CAP resulting from P aeruginosa, chronic liver disease, neurologic disease, nursing home, criteria of ARDS, acute renal failure, ICU admission, and inappropriate empiric treatment were the factors associated with 30-day mortality. Conclusions: P aeruginosa is an individual risk factor associated with mortality in CAP. The risk factors described can help clinicians to suspect P aeruginosa and MDR P aeruginosa

Differences in tetracycline resistance determinant carriage among Shigella flexneri and Shigella sonnei are not related to different plasmid Inc-type carriage

Objectives: The aim of this study was to establish the prevalence of the most common molecular mechanisms involved in tetracycline resistance as well as their relationship with plasmid incompatibility (Inc) groups in a collection of Shigella spp. causing traveller’s diarrhoea. Methods: Tetracycline susceptibility was established in 187 Shigella spp. (74 Shigella flexneri and 113 Shigella sonnei), of which 153 isolates were recovered as a confirmed cause of traveller’s diarrhoea. The prevalence of the tet(A), tet(B) and tet(G) genes was analysed by PCR. Eighteen plasmid Inc groups was determined in a subset of 59 isolates. Results: Among 154 tetracycline-resistant isolates, 122 (79.2%) harboured at least tet(A) or tet(B). The tet(B) gene was the most frequently detected, being present in 70 isolates (45.5%), whilst tet(A) was detected in 57 isolates (37.0%). The tet(G) gene was present in only 11 (7.2%) isolates. Moreover, the tet(A) gene was more frequent in S. sonnei (P = 0.0007), whilst the tet(B) gene was more frequent in S. flexneri (P < 0.0001). Plasmids belonging to Inc group B (P < 0.05) were significantly more frequent among S. flexneri, whilst those belonging to groups K, FIC and FIIA (P < 0.05) were preferentially detected among S. sonnei. Conclusion: The prevalence of the tet(A) and tet(B) genes differed between S. sonnei and S. flexneri. Moreover, the prevalence of plasmid Inc groups in S. flexneri and S. sonnei differed. However, no relationship was found between the two phenomena

Microbiology and outcomes of community acquired pneumonia in non cystic-fibrosis bronchiectasis patients

Background: It is general belief that Non-cystic fibrosis bronchiectasis (NCFB) is characterized by frequent community-acquired pneumonia. Nonetheless, the knowledge on clinical characteristics of CAP in NCFBE is poor and no specific recommendations are available. We aim to investigate clinical and microbiological characteristics of NCFBE patients with CAP. Methods: Prospective observational study of 3495 CAP patients (2000-2011). Results: We found 90 (2.0%) NCFBE-CAP that in comparison with non-bronchiectatic CAP (n, 3405) showed older age (mean ± [SD], NCFBE-CAP 73 ± 14 vs. CAP 65 ± 19yrs), more vaccinations (pneumococcal: 35% vs. 14%; influenza: 60% vs. 42%), comorbidities (n ≥ 2: 43% vs. 25%), previous antibiotics (38% vs. 22%), and inhaled steroids (53% vs. 16%) (p < 0.05 each). Streptococcus pneumoniae was the most frequent isolate in both groups (NCFBE-CAP 44.4% vs. CAP 42.7%; p = 0.821) followed by respiratory virus, mixed infections and atypical bacteria. Considering overall frequencies of the main pathogens (including monomicrobial and mixed infections) Pseudomonas aeruginosa (15.5% vs. 2.9%; p < 0.001) and Enterobacteriaceae (8.8% vs. 2.4%; p = 0.025) were more prevalent in NCFBE-CAP patients than in CAP. Despite these clinical and microbiological differences, NCFBE-CAP showed similar outcomes to CAP patients (mortality, length of hospital stay, etc.). Conclusions: NCFBE-CAP patients are usually older and have more comorbidities but similar outcomes than general CAP population. Usual CAP pathogens, such as S. pneumoniae, are also involved in NCFBE-CAP but P. aeruginosa and other Enterobacteriaceae were globally more frequent than in CAP. Therefore, a wide microbiological investigation should be recommended in all NCFBE-CAP cases as well as routine pneumococcal vaccination for prevention of pneumonia

Community-Acquired Pneumococcal Pneumonia in Virologically Suppressed HIV-Infected Adult Patients: A Matched Case-Control Study

Background: The study aimed to investigate whether the clinical presentations and outcomes (length of stay, ICU admission, and 30-day mortality) of pneumococcal pneumonia in virologically suppressed patients who were HIV-infected on ART with a CD4+ T-cell count > 350 cells/mm3 are comparable to those seen in patients with HIV, using a case-control design. Methods: A case-control study was carried out in Hospital Clinic, Barcelona, Spain (2001-2016). Control patients were matched by age (±10 years), sex, comorbidities, and pneumonia diagnosis in the same calendar period. Clinical presentation and outcomes of pneumococcal pneumonia in patients who were and were not infected with HIV were compared. Results: Pneumococcal pneumonia was studied in 50 cases (HIV infection) and 100 control patients (non-HIV infection). Compared with the control patients, case patients had higher rates of influenza (14% vs 2%, P = .007) and pneumococcal vaccination (10% vs 1%, P = .016). The group of cases also presented a higher rate of coinfection with hepatitis B virus (6% vs 0%, P = .036). Both groups presented similar ICU admission (18% vs 27%, P = .22), need for mechanical ventilation (12% vs 8%; P = .43), length of stay (7 days vs 7 days, P = .76), and 0% of 30-day mortality. No evidence was found of a more severe presentation or a worse clinical outcome in cases than in control patients. Conclusions: Pneumococcal pneumonia episodes requiring hospitalization in virologically suppressed patients with HIV with > 350 CD4+ T-cell count/mm3 were neither more severe nor had worse prognosis compared with uninfected patients. These results support the fact that such patients do not need treatment, admission, or care sites different to the general population

Rapid Diagnosis of Staphylococcal Catheter-Related Bacteraemia in Direct Blood Samples by Real-Time PCR

Catheter-related bacteremia (CRB) is an important cause of morbidity and mortality among hospitalized patients, being staphylococci the main etiologic agents. The objective of this study was to assess the use of a PCR-based assay for detection of staphylococci directly from blood obtained through the catheter to diagnose CRB caused by these microorganisms and to perform a cost-effectiveness analysis. A total of 92 patients with suspected CRB were included in the study. Samples were obtained through the catheter. Paired blood cultures were processed by standard culture methods and 4 ml blood samples were processed by GeneXpert-MRSA assay for the detection of methicillin-susceptible (MSSA) or methicillin-resistant (MRSA) Staphylococcus aureus, and methicillin-resistant coagulase-negative staphylococci (MR-CoNS). Sixteen CRB caused by staphylococci were diagnosed among 92 suspected patients. GeneXpert detected 14 out of 16 cases (87.5%), including 4 MSSA and 10 MR-CoNS in approximately 1 hour after specimen receipt. The sensitivity and specificity of GeneXpert were 87.5% (CI 95%: 60.4-97.8) and 92.1% (CI 95%: 83-96.7), respectively, compared with standard culture methods. The sensitivity of GeneXpert for S. aureus was 100%. Regarding a cost-effectiveness analysis, the incremental cost of using GeneXpert was of 31.1euro per patient while the incremental cost-effectiveness ratio of GeneXpert compared with blood culture alones was about 180euro per life year gained. In conclusion, GeneXpert can be used directly with blood samples obtained through infected catheters to detect S. aureus and MR-CoNS in approximately 1h after sampling. In addition, it is cost-effective especially in areas with high prevalence of staphylococcal CRB

Time-to-positivity, type of culture media and oxidase test performed on positive blood culture vials to predict Pseudomonas aeruginosa in patients with Gram-negative bacilli bacteraemia

OBJECTIVE: The aim of this study was to determine the usefulness of oxidase test and time-to-positivity (TTP) in aerobic and anaerobic blood culture vials to detect the presence of Pseudomonas aeruginosa in patients with Gram-negative bacilli (GNB) bacteraemia. METHODS: TTP was recorded for each aerobic and anaerobic blood culture vial of monomicrobial bacteraemia due to GNB. Oxidase test was performed in a pellet of the centrifuged content of the positive blood culture. An algorithm was developed in order to perform the oxidase test efficiently taking into account TTP and type of vial. RESULTS: A total of 341 episodes of GNB bacteraemia were analysed. Sensitivity, specificity, positive predictive value and negative predictive value of the oxidase test performed on positive vials with GNB to predict P. aeruginosa were 95%, 99%, 91%, and 99%, respectively. When growth was first or exclusively detected in anaerobic vials, P. aeruginosa was never identified hence the performance of the oxidase test could be avoided. When growth was only or first detected in aerobic vials, a TTP≥8h predicted P. aeruginosa in 37% or cases (63 of 169), therefore oxidase test is highly recommended. CONCLUSIONS: Oxidase test performed onto positive blood culture vials previously selected by TTP and type of vials is an easy and inexpensive way to predict P. aeruginosa. In most cases, this can lead to optimization of treatment in less than 24 hours

Taxes, Governance, and Debt Maturity Structure: International Evidence

We provide a cross-country evidence on the impact of corporate and personal income taxes, and corporate governance systems on debt maturity structures and leverage using a comprehensive sample of 212,642 firm-year observations based on a sample of 19,573 firms from 24 OECD countries over the period 1990 to 2015. We find longer debt maturities, higher leverage, and, in a dynamic setting, a greater propensity to decrease short-term debt, in countries with high investor protection and where the potentials for debt tax shields and after-tax return of investors are high. Our results imply that when investors are protected, firms tend to have optimal debt maturities to maximise the gains from tax shields and minimise the tax cost of equity. In contrast, in low protection countries, investors prefer their firms to opt for low debt that is mainly short-term to mitigate the risk-shifting and debt overhang problems even if this entails forgoing the debt tax shields. Our results hold for various robustness checks including the hierarchical linear model specification, which corrects for a number of OLS biases

Effectiveness of combination therapy versus monotherapy with a third-generation cephalosporin in bacteraemic pneumococcal pneumonia: A propensity score analysis

Objective: Combining a macrolide or a fluoroquinolone to beta-lactam regimens in the treatment of patients with moderate to severe community-acquired pneumonia is recommended by the international guidelines. However, the information in patients with bacteraemic pneumococcal pneumonia is limited. Methods: A propensity score technique was used to analyze prospectively collected data from all patients with bacteraemic pneumococcal pneumonia admitted from 2000 to 2015 in our institution, who had received empirical treatment with third-generation cephalosporin in monotherapy or plus macrolide or fluoroquinolone. Results: We included 69 patients in the monotherapy group and 314 in the combination group. After adjustment by PS for receiving monotherapy, 30-day mortality (OR 2.89; 95% CI 1.07-7.84) was significantly higher in monotherapy group. A higher 30-day mortality was observed in monotherapy group in both 1:1 and 1:2 matched samples although it was statistically significant only in 1:2 sample (OR: 3.50 (95% CI 1.03-11.96), P = 0.046). Conclusions: Our study suggests that in bacteraemic pneumococcal pneumonia, empirical therapy with a third-generation cephalosporin plus a macrolide or a fluoroquinolone is associated with a lower mortality rate than beta-lactams in monotherapy. These results support the recommendation of combination therapy in patients requiring admission with moderate to severe disease