Development of Aspergillosis in a cohort of non-neutropenic, non-transplant patients colonised by Aspergillus spp.

BACKGROUND: A previous study explored factors discriminating colonization and true infection among non-transplant, non-neutropenic patients with repeated Aspergillus spp. isolation from lower respiratory samples. The present study explored the evolution of patients with Aspergillus colonization in that study to determine the percentage of cases progressing to aspergillosis and time to development. METHODS: Clinical records were retrospectively reviewed (for each patient from his end date in the past study) and data from all respiratory processes suffered by patients up to April 2015 were recorded. Comparisons of variables were performed between colonized patients that developed aspergillosis and those that did not. A Kaplan-Meier curve was used to describe time to development of aspergillosis in chronic obstructive pulmonary disease (COPD) patients for II-IV stages of the Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification. RESULTS: Sixty seven colonized patients were followed, 12 of them (17.9%) developed aspergillosis. Diagnoses included six tracheobronchitis (4 invasive, 2 simple tracheobronchitis), four pulmonary disease (2 invasive pulmonary aspergillosis, 2 chronic pulmonary aspergillosis), one allergic bronchopulmonary aspergillosis and one pulmonary aspergilloma. Up to 47 (70.4%) of the study patients presented COPD. Among patients developing aspergillosis COPD was more frequent (100%) than among those that did not develop aspergillosis (35 out of 55; 63.6%) (p = 0.012), as well as GOLD IV patients were more frequent among COPD patients developing aspergillosis than among COPD patients that did not (50.0 vs. 26.1%, p = 0.046). Mean time to development of aspergillosis was 18.4 months (median: 8.5) with a wide range (1-58). Overtime, the percentage of patients developing aspergillosis was significantly higher among GOLD IV patients than among GOLD II-III patients (p = 0.032). CONCLUSIONS: The high percentage of cases progressing to aspergillosis among colonized patients, especially among those with COPD (25.5%), stresses the importance of colonization as risk factor, and creates awareness of the possible change from colonization to invasive disease in GOLD IV patients.

Risk factors for colonization by carbapenemase-producing enterobacteria at admission to a Surgical ICU: A retrospective study.

INTRODUCTION: In 2011, a hospital-wide outbreak of OXA-48 producing Klebsiella pneumoniae occurred in our hospital, an epidemiological setting of high ESBL-producing K. pneumoniae rates. This study identifies risk factors for colonization with carbapenemase-producing enterobacteria (CPE) at Surgical Intensive Care Unit (SICU) admission. METHODS: A 2-year retrospective study was performed in all patients admitted to the SICU that following routine had a rectal swab collected upon admission. RESULTS: Of 254 patients admitted, 41 (16.1%) harbored CPE (five showing two carbapenemase-producing isolates). Most frequent carbapenemase-producing isolates and carbapenemases were K. pneumoniae (39/46, 84.8%) and OXA-48 (31/46; 76.1%), respectively. Carriers significantly had higher rates of chronic renal disease, previous digestive/biliary endoscopy, hospitalization, ICU/SICU admission, intraabdominal surgery, and antibiotic intake, as well as higher median values of clinical scores (SOFA, SAPS II and APACHE II). In the multivariate analysis (R2=0.309, p<0.001), CPE carriage was associated with prior administration of 3rd-4th generation cephalosporins (OR=27.96, 95%CI=6.88, 113.58, p<0.001), ß-lactam/ß-lactamase inhibitor (OR=11.71, 95%CI=4.51, 30.43, p<0.001), abdominal surgery (OR=6.33, 95%CI=2.12, 18.89, p=0.001), and prior digestive/biliary endoscopy (OR=3.88, 95%CI=1.56, 9.67, p=0.004). CONCLUSIONS: A strong association between production of ESBLs and carriage of CPE (mainly OXA-48 producing K. pneumoniae) was found. According to the model, the co-selection of ß-lactamases by previous exposure to broad-spectrum cephalosporins and ß-lactam/ß-lactamase inhibitors (with lower relative risk), abdominal surgery and prior digestive/biliary endoscopy were factors associated with CPE carriage.

Micafungin pharmacokinetic/pharmacodynamic adequacy for the treatment of invasive candidiasis in critically ill patients on continuous venovenous haemofiltration.

OBJECTIVES: To explore the pharmacokinetics (PK) and pharmacodynamics (PD) of micafungin in patients undergoing continuous venovenous haemofiltration (CVVH). PATIENTS AND METHODS: Ten patients receiving CVVH treated with 100 mg/day micafungin were included (April-December 2012). CVVH was performed using polyethersulphone or polysulphone haemofilters. Dialysis membranes were not changed on sampling days. On Days 1 and 2, blood samples from arterial pre-filter and venous post-filter ports and ultrafiltrate samples were collected at the start and end of the infusion and at 3, 5, 8, 18 and 24 h. Concentrations were determined using HPLC. Values for the area under the concentration-time curve (AUC0-24) were calculated. Monte Carlo simulations were performed using pre-filter and post-filter AUC0-24/MIC ratios on Days 1 and 2. The probability of target attainment (PTA) was calculated using AUC0-24/MIC cut-offs: 285 (C. parapsilosis), 3000 (all Candida spp.) and 5000 (non-parapsilosis Candida spp.). Cumulative fraction responses (CFRs) were calculated using EUCAST MIC distributions. RESULTS: Mean post-filter AUC0-24 (mg·h/L) values were higher than pre-filter values on Day 1 (83.31 ±â€Š15.87 versus 71.31 ±â€Š14.24; P = 0.008) and Day 2 (119.01 ±â€Š27.20 versus 104.54 ±â€Š21.23; P = 0.005). PTAs were ≥90% for MICs of 0.125 mg/L (cut-off = 285), 0.016 mg/L (cut-off = 3000) and 0.008 mg/L (cut-off = 5000) on Day 1, and for MICs of 0.25 mg/L (cut-off = 285) and 0.016 mg/L (cut-off = 3000 and 5000) on Day 2, without differences between pre- and post-filter values. On Day 2, CFRs >90% were obtained for C. albicans (cut-off = 3000 and 5000) and C. glabrata (cut-off = 3000), but not for C. parapsilosis. CONCLUSIONS: There was no removal of micafungin by CVVH or need for dose adjustment, and there was optimal PK/PD coverage for non-parapsilosis Candida and equivalence of pre- and post-filter PD.

Influence of the MBC/MIC ratio on the antibacterial activity of vancomycin versus linezolid against methicillin-resistant Staphylococcus aureus isolates in a pharmacodynamic model simulating serum and soft tissue interstitial fluid concentrations reported in diabetic patients.

OBJECTIVES: To explore serum and tissue pharmacodynamics of linezolid versus vancomycin against methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates with different MBC/MIC ratios. METHODS: Five strains (vancomycin MIC/MBCs, mg/L) were used: TOL-1 (2/≥64), TOL-2 (1/16), LT-1 and LT-2 (1/8) and NT (1/2). The linezolid MIC/MBC for all strains was 2/≥64 mg/L. A two-compartment dynamic computerized device was used (inocula 10(7) cfu/mL). Free concentrations obtained in serum and interstitial fluid with twice-daily regimens of 1 g of vancomycin or 600 mg of linezolid were simulated over 48 h. ABBCs (differences between control growth curves and killing curves of bacteria exposed to antibiotics; log10 cfu × h/mL) and log10 reductions in initial inocula were calculated. RESULTS: In serum simulations, vancomycin (AUC0-24/MIC = 251.8 for TOL-1 and 503.6 for the remaining strains) was bacteriostatic against strains with MBC/MIC ≥8, but bactericidal against NT. In interstitial fluid simulations (AUC0-24/MIC = 54.6 for TOL-1 and 109.2 for the remaining strains), initial inocula grew in all cases. Linezolid, both in serum (AUC0-24/MIC = 87.0) and in interstitial fluid (AUC0-24/MIC = 130.6) simulations, reduced initial inocula ≥2.2 log10 for all strains (apart from LT-1 in serum simulations that showed a bacteriostatic profile). ABBCs were similar in serum and interstitial fluid with linezolid, but significantly lower in interstitial fluid simulations with vancomycin. CONCLUSIONS: From the pharmacodynamic perspective (serum concentrations), vancomycin tolerance should include MBC/MIC ≥8 since strains exhibiting this ratio showed bacteriostatic profiles similar to those obtained with isolates with MBC/MIC ratios of 16 or 32. Insufficient concentrations of vancomycin at the simulated infected site were linked to bacteriological failure. Free concentrations of linezolid at the infection site pharmacodynamically covered MRSA.

Macrolides and ß-lactam antibiotics enhance C3b deposition on the surface of multidrug-resistant Streptococcus pneumoniae strains by a LytA autolysin-dependent mechanism.

The emergence of Streptococcus pneumoniae strains displaying high levels of multidrug resistance is of great concern worldwide and a serious threat for the outcome of the infection. Modifications of the bacterial envelope by antibiotics may assist the recognition and clearance of the pathogen by the host immune system. Recognition of S. pneumoniae resistant strains by the complement component C3b was increased in the presence of specific anti-pneumococcal antibodies and subinhibitory concentrations of different macrolides and ß-lactam antibiotics for all the strains investigated. However, C3b levels were unchanged in the presence of serum containing specific antibodies and sub-MICs of levofloxacin. To investigate whether LytA, the main cell wall hydrolase of S. pneumoniae, might be involved in this process, lytA-deficient mutants were constructed. In the presence of antibiotics, loss of LytA was not associated with enhanced C3b deposition on the pneumococcal surface, which confirms the importance of LytA in this interaction. The results of this study offer new insights into the development of novel therapeutic strategies using certain antibiotics by increasing the efficacy of the host immune response to efficiently recognize pneumococcal resistant strains.

In vitro interference of tigecycline at subinhibitory concentrations on biofilm development by Enterococcus faecalis.

OBJECTIVES: Since biofilm formation is the hallmark of Enterococcus faecalis isolates, the aim of this study was to quantify biofilm formation in the presence of subinhibitory concentrations of tigecycline. METHODS: Interference of tigecycline on biofilm formation was spectrophotometrically quantified using 20 biofilm-producing E. faecalis isolates with tigecycline MICs of 0.12 (8 strains) or 0.25 mg/L (12 strains). Biofilm production was measured in antibiotic-free tryptic soy broth supplemented with 1% glucose and compared with biofilm production in the same medium with tigecycline at subinhibitory concentrations (0.25× or 0.5× MIC, similar to trough concentrations in serum or concentrations in the colon after a standard dose) by reading the optical density at 450 nm (OD(450)) after staining with Crystal Violet. RESULTS: In the presence of subinhibitory tigecycline concentrations, pooled OD(450) values for the 20 strains [median (IQR)] were significantly lower than those for controls: 0.468 (0.379-0.516) for antibiotic-free controls versus 0.295 (0.200-0.395) for 0.25× MIC tigecycline (P < 0.001) and 0.287 (0.245-0.479) for 0.5× MIC tigecycline (P < 0.001), with significant differences between pooled OD(450) values obtained with each concentration of tigecycline (P = 0.022). In 17 out of 20 (85%) strains the OD(450) obtained with 0.25× MIC tigecycline was significantly (P < 0.05) lower than the basal OD(450), while this occurred in 12 out of 20 (60%) strains with 0.5× MIC. CONCLUSIONS: In vitro tigecycline subinhibitory concentrations were able to interfere with biofilm formation by E. faecalis.

Retrospective epidemiological study for the characterization of community- acquired pneumonia and pneumococcal pneumonia in adults in a well-defined area of Badalona (Barcelona, Spain).

BACKGROUND: Community-acquired pneumonia (CAP) has large impact on direct healthcare costs, especially those derived from hospitalization. This study determines impact, clinical characteristics, outcome and economic consequences of CAP in the adult (≥18 years) population attended in 6 primary-care centers and 2 hospitals in Badalona (Spain) over a two-year period. METHODS: Medical records were identified by codes from the International Classification of Diseases in databases (January 1st 2008-December 31st 2009). RESULTS: A total of 581 patients with CAP (55.6% males, mean age 57.5 years) were identified. Prevalence: 0.64% (95% CI: 0.5%-0.7%); annual incidence: 3.0 cases/1,000 inhabitants (95% CI: 0.2-0.5). Up to 241 (41.5%) required hospitalization. Hospital admission was associated (p<0.002) with liver disease (OR=5.9), stroke (OR=3.6), dementia (OR=3.5), COPD (OR=2.9), diabetes mellitus (OR=1.9) and age (OR=1.1 per year). Length of stay (4.4±0.3 days) was associated with PSI score (ß=0.195), in turn associated with age (r=0.827) and Charlson index (r=0.497). Microbiological tests were performed in all inpatients but only in 35% outpatients. Among patients with microbiological tests, results were positive in 51.7%, and among them, S pneumoniae was identified in 57.5% cases. Time to recovery was 29.9±17.2 days. Up to 7.5% inpatients presented complications, 0.8% required ICU admission and 19.1% readmission. Inhospital mortality rate was 2.5%. Adjusted mean total cost was €2,332.4/inpatient and €698.6/outpatient (p<0.001). Patients with pneumococcal CAP (n=107) showed higher comorbidity and hospitalization (76.6%), higher PSI score, larger time to recovery and higher overall costs among inpatients. CONCLUSIONS: Strategies preventing CAP, thus reducing hospital admissions could likely produce substantial costs savings in addition to the reduction of CAP burden.

Repeated Aspergillus isolation in respiratory samples from non-immunocompromised patients not selected based on clinical diagnoses: colonisation or infection?

BACKGROUND: Isolation of Aspergillus from lower respiratory samples is associated with colonisation in high percentage of cases, making it of unclear significance. This study explored factors associated with diagnosis (infection vs. colonisation), treatment (administration or not of antifungals) and prognosis (mortality) in non-transplant/non-neutropenic patients showing repeated isolation of Aspergillus from lower respiratory samples. METHODS: Records of adult patients (29 Spanish hospitals) presenting ≥ 2 respiratory cultures yielding Aspergillus were retrospectively reviewed and categorised as proven (histopathological confirmation) or probable aspergillosis (new respiratory signs/symptoms with suggestive chest imaging) or colonisation (symptoms not attributable to Aspergillus without dyspnoea exacerbation, bronchospasm or new infiltrates). Logistic regression models (step-wise) were performed using Aspergillosis (probable + proven), antifungal treatment and mortality as dependent variables. Significant (p < 0.001) models showing the highest R2 were considered. RESULTS: A total of 245 patients were identified, 139 (56.7%) with Aspergillosis. Aspergillosis was associated (R2 = 0.291) with ICU admission (OR = 2.82), congestive heart failure (OR = 2.39) and steroids pre-admission (OR = 2.19) as well as with cavitations in X-ray/CT scan (OR = 10.68), radiological worsening (OR = 5.22) and COPD exacerbations/need for O2 interaction (OR = 3.52). Antifungals were administered to 79.1% patients with Aspergillosis (100% proven, 76.8% probable) and 29.2% colonised, with 69.5% patients receiving voriconazole alone or in combination. In colonised patients, administration of antifungals was associated with ICU admission at hospitalisation (OR = 12.38). In Aspergillosis patients its administration was positively associated (R(2) = 0.312) with bronchospasm (OR = 9.21) and days in ICU (OR = 1.82) and negatively with Gold III + IV (OR = 0.26), stroke (OR = 0.024) and quinolone treatment (OR = 0.29). Mortality was 78.6% in proven, 41.6% in probable and 12.3% in colonised patients, and was positively associated in Aspergillosis patients (R2 = 0.290) with radiological worsening (OR = 3.04), APACHE-II (OR = 1.09) and number of antibiotics for treatment (OR = 1.51) and negatively with species other than A. fumigatus (OR = 0.14) and aspergillar tracheobronchitis (OR = 0.27). CONCLUSIONS: Administration of antifungals was not always closely linked to the diagnostic categorisation (colonisation vs. Aspergillosis), being negatively associated with severe COPD (GOLD III + IV) and concomitant treatment with quinolones in patients with Aspergillosis, probably due to the similarity of signs/symptoms between this entity and pulmonary bacterial infections.

Adherence to recommendations by infectious disease consultants and its influence on outcomes of intravenous antibiotic-treated hospitalized patients.

BACKGROUND: Consultation to infectious diseases specialists (ID), although not always performed by treating physicians, is part of hospital's daily practice. This study analyses adherence by treating physicians to written ID recommendations (inserted in clinical records) and its effect on outcome in hospitalized antibiotic-treated patients in a tertiary hospital in Spain. METHODS: A prospective, randomized, one-year study was performed. Patients receiving intravenous antimicrobial therapy prescribed by treating physicians for 3 days were identified and randomised to intervention (insertion of written ID recommendations in clinical records) or non-intervention. Appropriateness of empirical treatments (by treating physicians) was classified as adequate, inadequate or unnecessary. In the intervention group, adherence to recommendations was classified as complete, partial or non-adherence. RESULTS: A total of 1173 patients were included, 602 in the non-intervention and 571 in the intervention group [199 (34.9%) showing complete adherence, 141 (24.7%) partial adherence and 231 (40.5%) non-adherence to recommendations]. In the multivariate analysis for adherence (R2 Cox=0.065, p=0.009), non-adherence was associated with prolonged antibiotic prophylaxis (p=0.004; OR=0.37, 95%CI=0.19-0.72). In the multivariate analysis for clinical failure (R2 Cox=0.126, p<0.001), Charlson index (p<0.001; OR=1.19, 95%CI=1.10-1.28), malnutrition (p=0.006; OR=2.00, 95%CI=1.22-3.26), nosocomial infection (p<0.001; OR=4.12, 95%CI=2.27-7.48) and length of hospitalization (p<0.001; OR=1.01, 95%CI=1.01-1.02) were positively associated with failure, while complete adherence (p=0.001; OR=0.35, 95%CI=0.19-0.64) and adequate initial treatment (p=0.010; OR=0.39, 95%CI=0.19-0.80) were negatively associated. CONCLUSIONS: Adherence to ID recommendations by treating physicians was associated with favorable outcome, in turn associated with shortened length of hospitalization. This may have important health-economic benefits and stimulates further investigation. TRIAL REGISTRATION: Current Controlled Trials ISRCTN83234896. http://www.controlled-trials.com/isrctn/sample_documentation.asp.

Correlation between clinical parameters characterising peri-implant and periodontal health: a practice-based research in Spain in a series of patients with implants installed 4-5 years ago.

OBJECTIVES: To explore peri-implant health (and relation with periodontal status) 4-5 years after implant insertion. STUDY DESIGN: A practice-based dental research network multicentre study was performed in 11 Spanish centres. The first patient/month with implant insertion in 2004 was considered. Per patient four teeth (one per quadrant) showing the highest bone loss in the 2004 panoramic X-ray were selected for periodontal status assessment. Bone losses in implants were calculated as the differences between 2004 and 2009 bone levels in radiographs. RESULTS: A total of 117 patients were included. Of the 408 teeth considered, 73 (17.9%) were lost in 2009 (losing risk: >50% for bone losses ≥7 mm). A total of 295 implants were reviewed. Eight of 117 (6.8%) patients had lost implants (13 of 295 implants installed; 4.4%). Implant loss rate (quadrant status) was 1.4% (edentulous), 3.6% (preserved teeth), and 11.1% (lost teeth) (p=0.037). The percentage of implant loss significantly (p<0.001) increased when the medial/distal bone loss was ≥3 mm. The highest (p≤0.001) pocket depths were found in teeth with ≥5 mm and implants with ≥3 mm bone losses, with similar mean values (≥4 mm), associated with higher rates of plaque index and bleeding by probing. CONCLUSIONS: The significant bi-directional relation between plaque and bone loss, and between each of these two parameters/signs and pocket depths or bleeding (both in teeth and implants, and between them) together with the higher percentage of implants lost when the bone loss of the associated teeth was ≥3 mm suggest that the patient's periodontal status is a critical issue in predicting implant health/lesion.

Evolution of clonal and susceptibility profiles of serotype 19A Streptococcus pneumoniae among invasive isolates from children in Spain, 1990 to 2008.

The genetic structure and antibiotic nonsusceptibility of all serotype 19A Streptococcus pneumoniae pediatric pneumococcal isolates received at the Spanish Pneumococcal Reference Laboratory (1990 to 2008) were analyzed. Of them, 410 (79.8%) isolates belonged to 14 sequence types (STs) with >10 isolates each, and 104 to 73 STs (with 21 new STs, ST5141 to ST5161, with one isolate each). Time trends in 2000 to 2008 (n=471) were explored by lineal regression. Serotype 19A increased from 5.7% in 2000 to 16.8% in 2008 (R2=0.872; P=0.001). Decreasing trends (P<0.03) were found for ST202 (R2=0.774) and ST81 (R2=0.559), and increasing trends (P<0.03) for ST878 (R2=0.544) and ST320 (R2=0.530), both belonging to the clonal complex (CC) Denmark(14)-32 and first detected in 2003 and 2007, respectively, and ST2013 (R2=0.704) and ST4461 (R2=0.707), both appearing in 2004. Penicillin nonsusceptibility was clustered in ST81, ST276, ST320, ST878, ST2013, and ST4461 (>90% nonsusceptibility), and amoxicillin and cefotaxime nonsusceptibility in ST320: 87% amoxicillin (MIC50/MIC90=8/8 µg/ml) and 43.5% cefotaxime (MIC50/MIC90=1/2 µg/ml) nonsusceptibility. No trends were found for erythromycin nonsusceptibility (ranging from 38.5% to 66.7%) and cefotaxime nonsusceptibility (ranging from 0.0% to 7.8%), but increasing trends (P<0.02) were found for oral penicillin (from 16.7% in 2000 to 56.3% in 2008; R2=0.628) and amoxicillin (from 0.0% before 2007 to 13.8% in 2008; R2=0.628) nonsusceptibility. This study warns about the emergence of serotype 19A STs associated with high-level antibiotic nonsusceptibility, with a role for ST320 and ST878 occupying the niche left by some pneumococcal 7-valent conjugate vaccine (PCV7)-related resistant STs. The rapid expansion of serotype 19A and STs related to antibiotic resistance indicates that vaccines covering serotype 19A present advantages in countering invasive disease.

Efficacy of simulated cefditoren versus amoxicillin-clavulanate free concentrations in countering intrastrain ftsI gene diffusion in Haemophilus influenzae.

This study explores the effects of cefditoren (CDN) versus amoxicillin-clavulanic acid (AMC) on the evolution (within a single strain) of total and recombined populations derived from intrastrain ftsI gene diffusion in ß-lactamase-positive (BL⁺) and ß-lactamase-negative (BL⁻) Haemophilus influenzae. DNA from ß-lactamase-negative, ampicillin-resistant (BLNAR) isolates (DNA(BLNAR)) and from ß-lactamase-positive, amoxicillin-clavulanate-resistant (BLPACR) (DNA(BLPACR)) isolates was extracted and added to a 107-CFU/ml suspension of one BL⁺ strain (CDN MIC, 0.007 µg/ml; AMC MIC, 1 µg/ml) or one BL⁻ strain (CDN MIC, 0.015 µg/ml; AMC MIC, 0.5 µg/ml) in Haemophilus Test Medium (HTM). The mixture was incubated for 3 h and was then inoculated into a two-compartment computerized device simulating free concentrations of CDN (400 mg twice a day [b.i.d.]) or AMC (875 and 125 mg three times a day [t.i.d.]) in serum over 24 h. Controls were antibiotic-free simulations. Colony counts were performed; the total population and the recombined population were differentiated; and postsimulation MICs were determined. At time zero, the recombined population was 0.00095% of the total population. In controls, the BL⁻ and BL⁺ total populations and the BL⁻ recombined population increased (from ≈3 log10 to 4.5 to 5 log10), while the BL⁺ recombined population was maintained in simulations with DNA(BLPACR) and was decreased by ≈2 log10 with DNA(BLNAR). CDN was bactericidal (percentage of the dosing interval for which experimental antibiotic concentrations exceeded the MIC [ft>MIC], >88%), and no recombined populations were detected from 4 h on. AMC was bactericidal against BL⁻ strains (ft>MIC, 74.0%) in DNA(BLNAR) and DNA(BLPACR) simulations, with a small final recombined population (MIC, 4 µg/ml; ft>MIC, 30.7%) in DNA(BLPACR) simulations. When AMC was used against the BL⁺ strain (in DNA(BLNAR) or DNA(BLPACR) simulations), the bacterial load was reduced ≈2 log10 (ft>MIC, 44.3%), but 6.3% and 32% of the total population corresponded to a recombined population (MIC, 16 µg/ml; ft>MIC, 0%) in DNA(BLNAR) and DNA(BLPACR) simulations, respectively. AMC, but not CDN, unmasked BL⁺ recombined populations obtained by transformation. ft>MIC values higher than those classically considered for bacteriological response are needed to counter intrastrain ftsI gene diffusion by covering recombined populations.

Increase in serotype 19A prevalence and amoxicillin non-susceptibility among paediatric Streptococcus pneumoniae isolates from middle ear fluid in a passive laboratory-based surveillance in Spain, 1997-2009.

BACKGROUND: Conjugate vaccines, such as the 7-valent conjugate vaccine (PCV7), alter serotype nasopharyngeal carriage, potentially increasing cases of otitis media by non-vaccine serotypes. METHODS: All paediatric middle ear fluid (MEF) isolates received in the Spanish Reference Laboratory for Pneumococci through a passive, laboratory-based surveillance system from January 1997 to June 2009 were analysed. Data from 1997 to 2000 were pooled as pre-vaccination period. Trends over time were explored by linear regression analysis. RESULTS: A total of 2,077 isolates were analysed: 855 belonging to PCV7 serotypes, 466 to serotype 19A, 215 to serotype 3, 89 to serotype 6A and 452 to other serotypes (< 40 isolates each). Over time, there has been a decreasing trend for PCV7 serotypes (R(2) = 0.944; p < 0.001, with significant decreasing trends for serotypes 19F, 14, 23F and 9V), and increasing trends for serotype 19A (R(2) = 0.901; p < 0.001), serotype 3 (R(2) = 0.463; p = 0.030) and other non-PCV7 serotypes (R(2) = 0.877; p < 0.001), but not for serotype 6A (R(2) = 0.311; p = 0.094). Considering all isolates, amoxicillin non-susceptibility showed an increasing trend (R(2) = 0.528; p = 0.017). Regarding serotype 19A, increasing trends in non-susceptibility to penicillin (R(2) = 0.726; p = 0.001), amoxicillin (R(2) = 0.804; p < 0.001), cefotaxime (R(2) = 0.546; p = 0.005) and erythromycin (R(2) = 0.546; p = 0.009) were found, with amoxicillin non-susceptibility firstly detected in 2003 (7.4%) and increasing up to 38.0% in 2009. In PCV7 serotypes (which prevalence decreased from 70.7% during 1997-2000 to 10.6% in 2009) amoxicillin non-susceptibility rates showed an increasing trend (R(2) = 0.702; p = 0.002). However, overall, amoxicillin non-susceptibility (≈25% in 2008-9) could be mainly attributed to serotype 19A (> 35% isolates) since PCV7 strains represented < 11% of total clinical isolates. CONCLUSIONS: In contrast to reports on invasive pneumococcal strains, in MEF isolates the reduction in the prevalence of PCV7 serotypes was not associated with decreases in penicillin/erythromycin non-susceptibility. The high prevalence of serotype 19A among paediatric MEF isolates and the amoxicillin non-susceptibility found in this serotype are worrisome since amoxicillin is the most common antibiotic used in the treatment of acute otitis media. These data suggest that non-PCV7 serotypes (mainly serotype 19A followed by serotypes 3 and 6A) are important etiological agents of acute otitis media and support the added value of the broader coverage of the new 13-valent conjugate vaccine.

Susceptibility of recently collected Spanish pneumococci nonsusceptible to oral penicillin from serotypes not included in the 7-valent conjugate vaccine.

The susceptibilities of pneumococci recently collected (up to June 2009) in Spain (500 isolates nonsusceptible to oral penicillin and 150 susceptible isolates) from serotypes not included in the conjugate vaccine were determined. Most nonsusceptible isolates (53.6%) belonged to serotype 19A. Susceptibility rates in serotype 19A penicillin-intermediate (n = 201)/penicillin-resistant (n = 67) isolates were <33%/< or =6.0% (erythromycin and oral cephalosporins with defined breakpoints), 85.1%/11.9% (amoxicillin), and 96.0%/52.2% (cefotaxime), respectively. Low susceptibility to common oral beta-lactams was also found in serotypes 11A (95.5% susceptibility to cefotaxime and erythromycin) and 35B.

Multicenter study evaluating the role of enterococci in secondary bacterial peritonitis.

A 1-year prospective multicenter study was performed to explore the significance of the presence of enterococci in cultures of peritoneal fluid from patients with secondary bacterial peritonitis in seven Spanish hospitals. The clinical records of patients with positive peritoneal fluid cultures were reviewed and distributed into cases (patients with cultures yielding enterococci) and controls (patients with cultures not yielding enterococci). Of a total of 158 records, 38 (24.1%) were cases and 120 (75.9%) were controls. The percentages or the scores (cases versus controls) for the variables included in the multivariate analysis were as follows: age of >50 years, 89.5% versus 68.3%; malignancy, 39.5% versus 18.3%; chronic obstructive pulmonary disease (COPD), 15.8% versus 4.2%; postoperative peritonitis, 55.3% versus 30.1%; nosocomial onset, 57.9% versus 34.2%; a higher Charlson comorbidity index, 3.29 +/- 3.38 versus 1.84 +/- 2.31; APACHE II score, 10.71 +/- 4.37 versus 8.76 +/- 5.49; ultimately or rapidly fatal disease, 63.2% versus 34.8%; need for surgical reintervention, 36.1% versus 15.1%; and admission to an intensive care unit, 45.9% versus 30.8%. In the multivariate analysis, enterococci were associated only with postoperative peritonitis (P = 0.009; odds ratio [OR] = 5.0; 95% confidence interval [CI] = 1.49 to 16.80), a higher Charlson comorbidity index (P = 0.002; OR = 1.30; 95% CI = 1.11 to 1.54), and COPD (P = 0.046; OR = 6.50; 95% CI = 1.04 to 40.73). The results of this study showed that enterococci were associated with comorbidity. An association with mortality could not be demonstrated.

Predictive model of short-term amputation during hospitalization of patients due to acute diabetic foot infections.

INTRODUCTION: Factors predicting short-term amputation during hospital treatment of patients admitted for acute diabetic foot infections are of interest for clinicians managing the acute episode. METHODS: A retrospective clinical records analysis of 78 consecutive patients hospitalized for acute diabetic foot infections was performed to identify predictive factors for short-term amputation by comparing the data of patients who ultimately required amputation and those who did not. Clinical/epidemiological, laboratory, imaging, and treatment variables were comparatively analyzed. A logistic regression model was performed, with amputation as the dependent variable and factors showing significant differences in the bivariate analysis as independent variables. A prediction score was calculated (and validated by ROC curve analysis) using beta coefficients for significant variables in the regression analysis to predict amputation. RESULTS: Of the 78 patients (70.5% with peripheral vasculopathy) included, 26 ultimately required amputation. In the bivariate analysis, white blood cell count, previous homolateral lesions, odor, lesion depth, sedimentation rate, Wagner ulcer grade, and arterial obstruction on Doppler study were significantly higher in patients ending in amputation. In the multivariate analysis, the risk of amputation was increased only by Wagner grade 4 or 5 (20-fold higher), obstruction (12.5-fold higher), and elevated sedimentation rate (6% higher per unit). Logistic regression predicted outcome in 76.9% of patients who underwent amputation and 92.3% of those who did not. CONCLUSION: The score calculated using beta coefficients for significant variables in the regression model (Wagner grades 4 and 5, obstruction on Doppler, and elevated sedimentation rate for the clinical, imaging, and laboratory data, respectively) correctly predicted amputation during hospital management of acute diabetic foot infections.

Genotypic versus phenotypic characterization, with respect to beta-lactam susceptibility, of Haemophilus influenzae isolates exhibiting decreased susceptibility to beta-lactam resistance markers.

Among 165 Spanish Haemophilus influenzae isolates with mutations in the ftsI gene (ftsI(+)) (2005 to 2007), 73% were beta-lactamase negative and 26.7% were positive. The proportion of beta-lactamase-negative isolates to beta-lactamase-positive isolates was 2:1 to 4:1 in general, versus 1:3 in pediatric hospitals. Among 44 beta-lactamase-positive strains, 8 strains produced ROB-1 (5 from the pediatric hospital). beta-Lactamase-positive ftsI(+) strains were phylogenetically closer than were beta-lactamase-negative strains.

Influence of different resistance traits on the competitive growth of Haemophilus influenzae in antibiotic-free medium and selection of resistant populations by different {beta}-lactams: an in vitro pharmacodynamic approach.

OBJECTIVES: The aim was to study the pharmacodynamics of cefditoren, amoxicillin/clavulanic acid and cefuroxime against mixed Haemophilus influenzae strains. METHODS: Isolates [MICs (mg/L) of cefditoren, cefuroxime and amoxicillin/clavulanic acid] used were: one beta-lactamase-negative (beta(-); 0.015, 1 and 1), one beta-lactamase-positive (beta(+); 0.03, 4 and 8) and two strains exhibiting ftsI gene mutations [one beta(-) ampicillin-resistant (BLNAR; 0.015, 8 and 4) and one beta(+) amoxicillin/clavulanic acid-resistant (BLPACR; 0.03, 8 and 4)]. A computerized pharmacodynamic model simulating free antibiotic concentrations (calculated considering reported percentages of protein binding) of 400 mg twice-daily cefditoren, 500 mg twice-daily cefuroxime and 875/125 mg three times daily amoxicillin/clavulanic acid was used to explore antibacterial activity against initial mixed inocula with 25% of each strain. Areas under bacterial curves (AUBCs) from 0 to 24 h (log cfu.h/mL) were calculated and differences between values in antibiotic-free (AUBC(K)) and in antibiotic simulations determined (ABBC(0-24) = AUBC(K0-24)-AUBC(0-24)). RESULTS: In antibiotic-free medium, total population increased by 1.7 log(10) cfu/mL from 0 to 24 h: final composition approximately 90% beta(-), approximately 6.5% beta(+), approximately 2.5% BLNAR and approximately 1% BLPACR. At the end of antibiotic simulations, the predominant population was BLPACR followed by beta(+) after amoxicillin/clavulanic acid or BLNAR after cefuroxime exposures. ABBC(0-24) was higher (P < 0.01) for cefditoren compared with cefuroxime or amoxicillin/clavulanic acid whether considering total population (70.4 versus approximately 33), beta(+) (77.8 versus approximately 52), BLNAR (66.1 versus 18.6-30.4) or BLPACR (40.8 versus approximately 0). CONCLUSIONS: Cefditoren offered higher antibacterial effect than cefuroxime and amoxicillin/clavulanic acid against a mixed population of H. influenzae strains due to its higher activity against beta-lactamase-producing strains and those carrying ftsI gene mutations.

In vitro effect of physiological concentrations of human albumin on the antibacterial activity of tigecycline.

OBJECTIVES: To determine C(max) tigecycline activity in the presence/absence of physiological concentrations of human albumin with free fraction concentrations as controls. METHODS: Killing curves (final inoculum: 1.0-5.0 x 10(7) cfu/mL) were performed with 0.88 mg/L final concentrations (serum C(max) after a 100 mg 1 h infusion) in Mueller-Hinton broth supplemented with Ca(2+) and Mg(2+) (MH) and in MH with 4 g/dL human albumin. Controls were curves in MH with concentrations similar to the free fraction (fC(max) = 0.17 mg/L) calculated using protein binding. Activity was measured as log(10) initial inoculum reduction (log(10) initial inoculum-log(10) at 12 h/24 h). Target strains (tigecycline MIC/MBC; mg/L) were: methicillin-resistant Staphylococcus aureus heteroresistant to vancomycin (0.12/0.25); Enterococcus faecium (0.12/0.25); Escherichia coli producing extended-spectrum beta-lactamase (0.12/0.25); and Acinetobacter baumannii (0.25/1). RESULTS: At 24 h the fC(max) produced mean decreases of < or =0.1 cfu/mL for all strains, in contrast to the bactericidal activity (mean >3 log(10) reduction) provided by C(max) concentrations in the presence or absence of albumin for E. coli and E. faecium, and an activity nearly bactericidal for S. aureus (mean approximately 2.8 log(10) reduction). In the case of the A. baumannii isolate the C(max) in the presence or absence of albumin produced a mean reduction of 2.56 log(10) cfu/mL at 12 h (time of one dosing interval), with a bacteriostatic profile when considering 24 h colony counts (similar counts at 0 and 24 h). CONCLUSIONS: Correcting the total concentration for the reported literature binding values is unreliable since tigecycline antibacterial activity was greater than that suggested by the free fraction of the drug.

Evaluating the optimal time for amikacin administration with respect to haemodialysis using an in vitro pharmacodynamic simulation against epidemic nosocomial OXA-48 producing Klebsiella pneumoniae ST405 strains.

OBJECTIVES: Bacterial viability and enrichment of resistance resulting from three different amikacin administration schedules with respect to haemodialysis (HD) were assessed against three OXA-48-producing Klebsiella pneumoniae isolated during an outbreak in a Spanish hospital. METHODS: A previously described two-compartment dynamic system was used. Three possible amikacin administration schedules were simulated: (i) haemodialysis immediately after amikacin infusion (pre-HD); (ii) infusion immediately after haemodialysis (post-HD); and (iii) infusion at 50% interdialytic period. Amikacin standard dose (SD) and double dose (DD) were simulated for each schedule. Values of Cmax/MIC, Cmax/MPC (mutant prevention concentration), AUC0-48h/MIC, AUC0-48h/MPC and %TMSW (percentage of time that the concentration was inside the mutant selection window) were determined with experimental data and were correlated with the area under the bacterial killing curve of the total population and the resistant subpopulation. RESULTS: Both with SD and DD, the pre-HD schedule resulted in increases at 48h in bacterial counts of the total population at the expense of enrichment of pre-existing resistant subpopulations from 12h onwards for all strains. The estimated %TMSW that prevented enrichment of resistant mutants was <61.5%. The AUC0-48h/MPC (with values of ≈40 being associated with countering of increases in resistant subpopulations) was better than the %TMSW as a predictive parameter. CONCLUSION: This study showed that the longest times concentrations were above the MPC (i.e. highest AUC0-48h/MPC, lowest %TMSW), the lowest enrichment of resistant subpopulations. This implies use of the highest possible amikacin dose (limited by toxicity) and post-HD as the best administration schedule.