Javier Garau

A Multinational Survey of Risk Factors for Infection with Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae in Nonhospitalized Patients

BACKGROUND Infections caused by extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae are increasing in frequency and are associated with high mortality rates. Circulation of CTX-M-type ESBLs in the community is of particular concern, because it may confound standard infection-control measures. METHODS We analyzed the results of epidemiologic studies of infection caused by ESBL-producing Enterobacteriaceae in nonhospitalized patients from 6 centers in Europe, Asia, and North America. Risk factors for infection with an ESBL-producing organism were identified by univariate and multivariate analyses. RESULTS A total of 983 patient-specific isolates were reviewed (890 [90.5%] of which were Escherichia coli, 68 [6.9%] of which were Klebsiella species, and 25 [2.5%] of which were Proteus mirabilis); 339 [34.5%] of the isolates produced ESBLs. CTX-M types were the most frequent ESBLs (accounting for 65%). Rates of co-resistance to ciprofloxacin among ESBL-producing isolates were high (>70%), but significant variation was seen among centers with respect to rates of resistance to gentamicin, amoxicillin-clavulanate, and trimethoprim-sulfamethoxazole. Similar risk factors for infection with an ESBL-producing organism were found in the different participating centers. Significant risk factors, identified by multivariate analysis, were recent antibiotic use, residence in a long-term care facility, recent hospitalization, age 65 years, and male sex (area under the receiver-operator characteristic [ROC] curve, 0.80). However, 34% of ESBL-producing isolates (115 of 336 isolates) were obtained from patients with no recent health care contact; the area under the ROC curve for the multivariate model for this group of patients was only 0.70, which indicated poorer predictive value. CONCLUSIONS Community-acquired ESBL-producing Enterobacteriaceae are now prevalent worldwide, necessitating international collaboration. Novel approaches are required to adequately address issues such as empirical treatment for severe community-acquired infection and infection control.

New insights into meticillin-resistant Staphylococcus aureus (MRSA) pathogenesis, treatment and resistance

Meticillin-resistant Staphylococcus aureus (MRSA) remains one of the principal multiply resistant bacterial pathogens causing serious healthcare-associated and community-onset infections. This paper reviews recent studies that have elucidated the virulence strategies employed by MRSA, key clinical trials of agents used to treat serious MRSA infections, and accumulating data regarding the implications of antibacterial resistance in MRSA for clinical success during therapy. Recent pre-clinical data support a species-specific role for Panton-Valentine leukocidin in the development of acute severe S. aureus infections and have elucidated other virulence mechanisms, including novel modes of internalisation, varying post-invasion strategies (featuring both upregulation and downregulation of virulence factors) and phenotypic switching. Recent double-blind, randomised, phase III/IV clinical trials have demonstrated the efficacy of linezolid and telavancin in hospital-acquired pneumonia (HAP) and complicated skin and skin-structure infections (cSSSIs) caused by MRSA. Tigecycline was non-inferior to imipenem/cilastatin in non-ventilator-associated HAP but was inferior in ventilator-associated pneumonia and has shown a higher rate of death than comparators on meta-analysis. Ceftaroline was clinically and microbiologically non-inferior to vancomycin/aztreonam in the treatment of MRSA cSSSI. Key resistance issues include a rise in vancomycin minimum inhibitory concentrations in MRSA, reports of clonal isolates with linezolid resistance mediated by acquisition of the chloramphenicol/florfenicol resistance gene, and case reports of daptomycin resistance resulting in clinical failure. Novel antimicrobial targets must be identified with some regularity or we will face the risk of untreatable S. aureus infections.

Risk Factors for Hospital Readmission in Patients with Chronic Obstructive Pulmonary Disease

Background: Hospital readmissions for acute exacerbation of chronic obstructive pulmonary disease (COPD) are one of the leading causes of healthcare expenditures worldwide. Objectives: To identify risk factors for hospital readmission in COPD patients. Methods:We prospectively evaluated 129 consecutive patients hospitalized for acute exacerbation of COPD. Clinical, spirometric and arterial blood gas variables were measured during hospitalization. Socioeconomic characteristics, comorbidity, dyspnea, functional dependence, depression, social support and quality of life were also analyzed. Readmission was defined as one or more hospitalizations in the following year. Results:During the follow-up period, 75 (58.5%) patients were readmitted. In bivariate analysis, readmission was associated with previous hospitalization for COPD in the past year, dyspnea scale, PaCO2 at discharge, depression, cor pulmonale, chronic domiciliary oxygen and quality of life measured by the St. George’s Respiratory Questionnaire. In multivariate analysis, the best predictor of readmission was the combination of hospitalization for COPD in the previous year (odds ratio, OR: 4.27; 95% confidence interval, CI: 1.5–12), the total score of the St. George’s Respiratory Questionnaire ≧50 points (OR: 2.36; 95% CI: 1.03–5.04) and PaCO2 at discharge ≧45 mm Hg (OR: 2.18; 95% CI: 0.84–5.06). With this model, the probability of readmission for patients without any of these variables was 7%, while it was 70% for the patients with all three variables present. Conclusion: The combination of quality of life, hospitalization for COPD in the previous year and hypercapnia at discharge are useful predictors of readmission at 1 year.

Effects of systemic steroids in patients with severe community-acquired pneumonia

The benefit of systemic steroids as adjunctive treatment in patients with severe community-acquired pneumonia (CAP) remains unclear. The present study aimed to evaluate the impact of corticosteroid treatment on mortality in patients with severe CAP. A retrospective, observational study of a cohort of patients hospitalised with severe CAP, classes IV and V of the Prognostic Severity Index score, was carried out. Information on epidemiological, clinical and laboratory data, and 30-day mortality was collected from medical charts. Of the 308 patients evaluated, 238 (77%) were treated with standard antimicrobial therapy and 70 (23%) received both antibiotics and systemic steroids. Clinical characteristics were similar between steroid and nonsteroid groups, except in the prevalence of male sex and the presence of chronic obstructive pulmonary disease. Systemic steroids were independently associated with a decreased mortality (odds ratio 0.287; 95% confidence interval 0.113–0.732), while severity of CAP (2.923; 1.262–6.770) was the only independent factor associated with increased mortality. Mortality decreased in the patients with severe CAP who received simultaneous administration of systemic steroids along with antibiotic treatment. Severity of community-acquired pneumonia remains the most important risk factor associated with increased mortality.

Group B Streptococcal Meningitis in Adults: Report of Twelve Cases and Review

Group B streptococcus (GBS) is the leading etiologic agent of bacterial meningitis and sepsis during the neonatal period, but it is an infrequent cause of meningitis in adults. We report 12 episodes of group B streptococcal meningitis in adults and review 52 cases reported in the literature. A total of 24 men and 40 women were included in the study; the mean age (+/- SD) was 49.2 +/- 20.5 years (range, 17-89 years). All the patients had cerebrospinal fluid cultures positive for GBS. Eighty-six percent of the patients had comorbid conditions, 50% had a distant focus of infection, and blood cultures yielded GBS for 78.7%. The overall case-fatality rate was 34.4% (22 patients). Factors associated with a poor outcome were advanced mean age (+/- SD) (61.5 +/- 17.4 years vs. 42.8 +/- 19.2 years; P = .0003) and the presence of complications on admission (P = .0001). Seven percent of survivors had neurological sequelae. Group B streptococcal meningitis in adults has become increasingly frequent in recent years; it tends to occur in patients with severe underlying conditions and is associated with a high case-fatality rate. Factors associated with a poor prognosis are advanced age and the occurrence of neurological and extraneurological complications.

Pseudomonas aeruginosa in patients hospitalised for COPD exacerbation: a prospective study.

Risk factors for Pseudomonas aeruginosa (PA) isolation in patients hospitalised for chronic obstructive pulmonary disease (COPD) exacerbation remain controversial. The aim of our study was to determine the incidence and risk factors for PA isolation in sputum at hospital admission in a prospective cohort of patients with acute exacerbation of COPD. We prospectively studied all patients with COPD exacerbation admitted to our hospital between June 2003 and September 2004. Suspected predictors of PA isolation were studied. Spirometry tests and 6-min walking tests were performed 1 month after the patients were discharged. High-resolution computed tomography (HRCT) was performed in a randomised manner in one out of every two patients to quantify the presence and extent of bronchiectasis. Patients were followed up during the following year for hospital re-admissions. A total of 188 patients were included, of whom 31 (16.5%) had PA in sputum at initial admission. The BODE (body mass index, airflow obstruction, dyspnoea, exercise capacity) index (OR 2.18, CI 95% 1.26–3.78; p = 0.005), admissions in the previous year (OR 1.65, CI 95% 1.13–2.43; p = 0.005), systemic steroid treatment (OR 14.7, CI 95% 2.28–94.8; p = 0.01), and previous isolation of PA (OR 23.1, CI 95% 5.7–94.3; p<0.001) were associated with PA isolation. No relationship was seen between bronchiectasis in HRCT and antibiotic use in the previous 3 months. PA in sputum at hospital admission is more frequent in patients with poorer scoring on the BODE index, previous hospital admissions, oral corticosteroids and prior isolation of PA.

Foodborne Nosocomial Outbreak of SHV1 and CTX-M-15–producing Klebsiella pneumoniae: Epidemiology and Control

BACKGROUND We describe a foodborne nosocomial outbreak due to extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae. METHODS An outbreak of ESBL K. pneumoniae was detected in March 2008. Initial control measures included contact isolation and a protocol for routine detection and reinforcement in hand hygiene practices. ESBL producers were screened for the bla(TEM), bla(SHV), and bla(CTX-M) genes. Pulsed-field gel electrophoresis analysis was performed using XbaI as a restriction endonuclease. RESULTS One hundred fifty-six colonized and/or infected patients were identified, 35 (22.4%) of whom had infection. The outbreak affected all hospital wards. Fecal carriage was up to 38% of patients in some wards. Of note, investigation revealed a very short delay between admission and colonization. None of the health care workers or environmental surfaces in the wards was found to be colonized. This prompted an epidemiological investigation of a possible foodborne transmission. We found that up to 35% of the hospital kitchen-screened surfaces or foodstuff were colonized and that 6 (14%) of 44 food handlers were found to be fecal carriers. Phenotypic and genotypic analysis of all clinical, environmental, and fecal carrier isolates showed the dissemination of a single strain of SHV-1 and CTX-M-15-producing K. pneumoniae. At that time, structural and functional reforms in the kitchen were performed. These were followed by a progressive reduction in colonization and infection rates among inpatients until complete control was obtained in December 2008. No restrictions in the use of antibiotics were needed. CONCLUSIONS To our knowledge, this is the first reported hospital outbreak that provides evidence that food can be a transmission vector for ESBL K. pneumoniae.

Pulmonary capillary hemangiomatosis associated with primary pulmonary hypertension: report of 2 new cases and review of 35 cases from the literature.

Pulmonary capillary hemangiomatosis (PCH) is a rare cause of primary pulmonary hypertension characterized by thin-walled microvessels infiltrating the peribronchial and perivascular interstitium, the lung parenchyma, and the pleura. These proliferating microvessels are prone to bleeding, resulting in accumulation of hemosiderin-laden macrophages in alveolar spaces. Here we report 2 cases of PCH with pulmonary hypertension, 1 of them associated with mechanical intravascular hemolysis, a feature previously reported in other hemangiomatous diseases, but not in PCH. Case 2 was diagnosed by pulmonary biopsy; to our knowledge the patient is the second adult to be treated with interferon α-2a.Review of the literature identified 35 patients with PCH and pulmonary hypertension. The prognosis is poor and median survival was 3 years from the first clinical manifestation. Dyspnea and right heart failure are the most common findings of the disease. Hemoptysis, pleural effusion, acropachy, and signs of pulmonary capillary hypertension are less common. Chest X-ray or computed tomography scan usually shows evidence of interstitial infiltrates, pulmonary nodules, or pleural effusion. Hemodynamic features include normal wedge pressures. Radiologic and hemodynamic findings are undifferentiated from those of pulmonary veno-occlusive disease but differ from other causes of primary pulmonary hypertension.Epoprostenol therapy, considered the treatment of choice in patients with primary pulmonary hypertension, may produce pulmonary edema and is contraindicated in patients with PCH. Regression of lesions was reported in 1 patient treated with interferon therapy and 2 other patients stabilized, including our second patient. PCH was treated successfully by lung transplantation in 5 cases. Early recognition of PCH in patients with suspected primary pulmonary hypertension is possible based on clinical and radiologic characteristics. Diagnosis by pulmonary biopsy is essential for allowing appropriate treatment.

Management of serious meticillin-resistant Staphylococcus aureus infections: what are the limits?☆

Severe (life-threatening) meticillin-resistant Staphylococcus aureus (MRSA) infection continues to be treated with vancomycin despite accumulating evidence of poor outcome, increasing resistance and unachievable pharmacokinetic/pharmacodynamic (PK/PD) targets. The minimum inhibitory concentration (MIC) susceptibility breakpoint for vancomycin was recently reduced to 2 mg/L. Whilst the great majority of clinical isolates are thus still classified as susceptible, the available clinical evidence argues for a method-dependent breakpoint of 0.5 mg/L (broth dilution) or 1.0 mg/L (Etest), which would classify many strains as resistant, or at best intermediate. However, automated susceptibility testing systems are not currently capable of performing accurately at this low level, and such low breakpoints are unsatisfactory because the poor reproducibility of tests (plus or minus one doubling dilution) results in a critical non-reproducibility around the modal MIC of 1 mg/L described in most published data. Therefore, vancomycin should be used with caution in severe (life-threatening) staphylococcal disease and the MIC should always be reported by method. Daptomycin is generally preferred for bacteraemia/endocarditis and linezolid for pneumonia. Better outcome data for vancomycin, based on achievable PK/PD targets and using robust MIC tests, are urgently required.

Of mice and men: innate immunity in pneumococcal pneumonia

Pneumococcal pneumonia is characterised by an intense inflammatory response induced mainly by cell wall components of the bacterium. Recognition of cell wall components by Toll-like receptors (TLRs) induces intracellular signalling pathways that culminate in the activation of pro-inflammatory genes through nuclear factor kappaB (NF-kappaB). Tumour necrosis factor-alpha (TNFalpha) is one of the earliest mediators produced and induces a second wave of pro- and anti-inflammatory cytokines that orchestrate the immune response. The magnitude of this response in patients with pneumococcal pneumonia is a complex network and many factors must be considered in the analysis of the cytokine production pattern. First, bacterial growth and the inflammatory response are dynamic processes, produced initially as a local phenomenon with a late systemic extension. Second, host characteristics, such as different cytokine gene polymorphisms, can cause a distinct immune response. Finally, other microorganism determinants and even the immunomodulatory effect of antimicrobials may play a role in cytokine production. Recent data on innate immunity against Streptococcus pneumoniae gathered from the murine model of pneumonia, from studies of human genetic polymorphisms associated with increased susceptibility to pneumococcal infection, and from human clinical trials are discussed. Special emphasis has been placed on the description of the chronology of the complex network of innate immunity triggered by pneumococcal infection.