Relationship between bone quantitative ultrasound and mortality: a prospective study

In a cohort of 5,201 women [72.3 +/- 5.3 years] from 58 primary care centers in Spain, followed for three years, no relationship between heel QUS parameters and overall mortality was found. However, a significant relationship between a low speed of sound (SOS) and vascular mortality was observed.

INTRODUCTION

An inverse relationship between mortality and bone mineral density measured by dual-energy absorption densitometry or quantitative bone ultrasound (QUS) has been described. The aim of the present study was to test this relationship in the ECOSAP cohort, a 3-year prospective study designed to assess the ability of heel QUS and clinical risk factors to predict non-vertebral fracture risk in women over 64.

METHODS

A cohort of 5,201 women [72.3 +/- 5.3 years] was studied. QUS was assessed with the Sahara(R) bone sonometer. Women attended follow-up visits every 6 months. Physicians recorded if the patient died and cause of death. Hazard rates (HR) of all-cause and vascular mortality per one standard deviation reduction in QUS parameters were determined.

RESULTS

One hundred (1.9%) women died during a median of 36.1 months follow-up, for a total of 14,999 patient-years, 42 because of vascular events (both cardiovascular and cerebrovascular). After adjusting for age, none of the QUS variables showed statistically significant differences between the patients who died and the survivors. In the final multivariate model, adjusted for age, current thyroxine and hypoglycaemic drug use, chronic obstructive pulmonary disease and decreased visual acuity, SOS was marginally non-significant: (HR: 1.19; 0.97-1.45). However, each 1 SD reduction in SOS was associated with a 39% increase in vascular mortality (HR: 1.39; 1.15-1.66).

CONCLUSIONS

In our cohort, SOS was related with vascular mortality, but not overall mortality.

Biofilm formation in Acinetobacter baumannii: associated features and clinical implications

Biofilm formation in 92 unrelated strains of Acinetobacter baumannii isolated in a multicentre cohort study was investigated using a microtitre plate assay. Fifty-six (63%) isolates formed biofilm. These isolates were less frequently resistant to imipenem or ciprofloxacin than were non-biofilm-forming isolates (25% vs. 47%, p 0.04; and 66% vs. 94%, p 0.004, respectively). All catheter-related urinary or bloodstream infections and the sole case of shunt-related meningitis were caused by biofilm-forming strains. Multivariate analysis revealed that treatment in an intensive care unit, ciprofloxacin resistance and isolation from a respiratory sample were associated with non-biofilm-forming isolates, while previous aminoglycoside use was associated with biofilm-forming isolates.

False extended-spectrum beta-lactamase detection in Acinetobacter spp. due to intrinsic susceptibility to clavulanic acid

BACKGROUND

There are some reports showing the susceptibility of some strains of Acinetobacter baumannii to the beta-lactamase inhibitor clavulanic acid. To address this issue, we determined the MIC of clavulanic acid for a broad collection of Acinetobacter spp. isolates collected in a multicentre study. In addition, we showed the consequences of this susceptibility to yield false extended-spectrum beta-lactamase (ESBL) detection in this genus.

METHODS

The strains used were 244 isolates of Acinetobacter (226 A. baumannii, 15 Acinetobacter genomic species 3 and 3 unidentified Acinetobacter spp.) and several A. baumannii as positive controls. The isolates were subjected to molecular typing. One isolate of each genotype was subjected to clavulanic acid MIC analysis. As no breakpoints for clavulanic acid are available, we arbitrarily established three categories of susceptibility: < or = 16, 32-128 and > or = 256 mg/L. The presence of ESBL in Acinetobacter spp. was analysed by using microdilution, double disc diffusion, combined discs, Etest and isoelectric focusing.

RESULTS

A total of 100 different genotypes were detected. Among them, 44, 26 and 30 genotypes were inhibited by < or = 16, 32-128 and > or = 256 mg/L clavulanic acid, respectively. Representative isolates of each group were tested for ESBL production. Only those with the lower clavulanic acid MICs yielded a false-positive ESBL test with all methods tested with the exception of the double disc diffusion assay.

CONCLUSIONS

Forty-four per cent of the genotypes tested were inhibited by < or = 16 mg/L clavulanic acid and these Acinetobacter isolates yielded a false ESBL-positive test. These results may have implications for susceptibility testing in routine microbiology laboratories.

[Frequency of bacterial contamination of epidural and plexus catheters in postoperative analgesia]

OBJECTIVE

There is little available information regarding contamination of perineural catheters. Incidence ranges from 5% to 57%, depending on the location of the catheter. The objective of this prospective study was to evaluate the incidence and predisposing factors of bacterial contamination of these catheters.

PATIENTS AND METHODS

The study included 47 patients who had an epidural (24 patients) or perineural (23 patients) catheter inserted for a minimum of 48 hours. We recorded details of the patients' characteristics, difficulty of insertion and duration of placement of the catheter, antibiotic treatment received, and signs of local or systemic infection immediately after surgery. When the catheters were removed, cultures were prepared using the Maki method. A descriptive analysis was performed and the frequency of contamination was determined using various parameters.

RESULTS

The incidence of contamination was 28% (13 patients): 5/24 (21%) in epidural catheters, 6/17 (35%) in femoral catheters, and 2/6 (33%) in brachial and sciatic plexus catheters. Colonization was not influenced by the patients' characteristics, technical difficulties in placing the catheter, prophylactic antibiotic treatment, or the characteristics of the infusion administered. None of the patients presented clinical signs of infection. The most commonly isolated microorganism was Staphylococcus epidermidis, found in 10 patients (69% of the colonized catheters).

CONCLUSIONS

Although infection of perineural catheters is exceptional when they are placed for 2 or more days, contamination is very common. Epidemiological studies are required to evaluate the variables involved.

High prevalence of carbapenem-hydrolysing oxacillinases in epidemiologically related and unrelated Acinetobacter baumannii clinical isolates in Spain

Carbapenem-hydrolysing oxacillinases are reported increasingly in Acinetobacter baumannii. This study investigated the role of these beta-lactamases in causing resistance to carbapenems in 83 epidemiologically related and unrelated imipenem-resistant A. baumannii clinical isolates. The isolates were also analysed for the presence of ISAba1 in the promoter region of the bla(OXA-51)-like gene in order to investigate the role of ISAba1 in OXA-51 expression. All clinical isolates contained a bla(OXA-51)-like gene, 20% contained a bla(OXA-58)-like gene, and 42% contained a bla(OXA-40)-like gene; bla(OXA-23)-like, bla(IMP) and bla(VIM) genes were not detected in any of the isolates investigated. ISAba1 was found in 24 (82.7%) of 28 pulsetypes, and was located in the promoter region of the bla(OXA-51)-like gene in five (20.8%) of these pulsetypes. Expression of bla(OXA-51) was detected in the five isolates with ISAba1 located in the promoter region, but was not detected in an isogenic imipenem-susceptible A. baumannii isolate that did not have ISAba1 located in the promoter region. It was concluded that there is a high prevalence of oxacillinases with activity against carbapenems among genetically unrelated A. baumannii clinical isolates from Spain, and that concomitant expression of two carbapenemases (OXA-51-like and either OXA-40-like or OXA-58-like) may take place. Insertion of an ISAba1-like element in the promoter of the bla(OXA-51)-like gene promotes the expression of this gene, although this did not seem to play a major role in carbapenem resistance.

Evaluation of biodiesel as bioremediation agent for the treatment of the shore affected by the heavy oil spill of the Prestige

The efficiency of different bioremediation products (nutrients, microorganisms and biodiesel) was tested using tiles located in both the supra-littoral and intertidal zones of a beach that was affected by the heavy oil spill of the Prestige. Neither nutrients nor microorganisms meant an improvement with respect to the natural processes. The addition of biodiesel improved the appearance of the treated tiles and apparently accelerated the degradation of the aliphatic and aromatic fractions of the residual fuel oil. Nevertheless, PAHs degradation was similar and very high in all the treatments (80-85% after 60 days). On the other hand, the evolution with time of the amount of vanadium was similar to that of 17alpha(H),21beta(H)-hopane, so it was concluded that vanadium could also be used to estimate the extent of oil degradation in the field. These results also suggested that the residual fuel oil mineralization was very low throughout 1 year in all the treatments. Moreover, the increase of the oxygen content of the residual oil from around 1% till 4-8% indicated that the partial oxidation of hydrocarbons took place, and that the hydrocarbon oxidation products accumulated in the polar fractions. In general, the results pointed out that bioremediation techniques were not suitable for the recovery of shores affected by heavy oil spills.

Prediction of absolute risk of non-spinal fractures using clinical risk factors and heel quantitative ultrasound

The relationship between osteoporosis risk factors, bone quantitative ultrasound (QUS) and non-spinal fracture risk was estimated in a cohort of 5,201 postmenopausal women from Spain who were prospectively evaluated during three years. Several clinical risk factors and low heel QUS values were independently associated with non-spinal fracture risk.

INTRODUCTION

Low-trauma, non-spinal fractures are a growing source of morbidity and mortality in the elderly. The aim of the present study was to examine the association of heel quantitative ultrasound (QUS) and a series of osteoporosis and fracture risk factors, with incident low energy non-spinal fractures in a population of elderly women, and to incorporate them into fracture prediction models.

METHODS

5,201 women aged 65 or older were enrolled in a three-year cohort study. Participants completed an osteoporosis and fracture risk factors questionnaire. QUS was measured at the heel with a gel-coupled device. Cox-proportional hazard analyses were performed to evaluate the association with the first incident low-trauma non-spinal fracture.

RESULTS

Three hundred and eleven women (6.0%) sustained a total of 363 low-trauma fractures, including 133 forearm/wrist, 54 hip, 50 humerus, 37 leg and 17 pelvic fractures. For every standard deviation decrease in the quantitative ultrasound index, the adjusted hazard ratios (95% CI) for any non-vertebral, hip, forearm/wrist, and humerus fractures were 1.31 (1.15-1.49), 1.40 (1.01-1.95), 1.50 (1.19-1.89) and 1.35 (0.97-1.87), respectively. Similar results were observed with other QUS variables. The best predictive models indicated that age, a history of falls, a previous low-trauma fracture, a family history of fracture, a calcium intake from dairy products of less than 250 mg/day, and lower values of QUS parameters were independently associated with the risk of non-spinal fractures.

CONCLUSIONS

Both clinical risk factors and QUS are independent predictors of risk of fragility non-spinal fractures. A prediction algorithm using these variables was developed to estimate the absolute risk of non-spinal fractures in elderly women in Spain.

Biofilm formation in uropathogenic Escherichia coli strains: relationship with prostatitis, urovirulence factors and antimicrobial resistance

PURPOSE

Escherichia coli strains are the most frequent cause of urinary tract infections. Biofilm formation allows the strains to persist a long time in the genitourinary tract and interfere with bacterial eradication. We determined the possible relationships between the different urinary tract infections, and in vitro biofilm formation, the presence of urovirulence factors and nalidixic acid resistance.

MATERIALS AND METHODS

A total of 151 E. coli strains collected from patients with cystitis (44 strains), pyelonephritis (75) and prostatitis (32) were analyzed for in vitro biofilm formation, the phylogenetic group, the presence of several urovirulence factors and resistance to nalidixic acid.

RESULTS

E. coli strains causing prostatitis produced biofilm in vitro more frequently than those causing other urinary tract infections and had a higher frequency of hemolysin (p = 0.03 and 0.0002, respectively). However, only hemolysin was independently associated with prostatitis. On the other hand, strains forming biofilm presented a significantly higher frequency of hemolysin and type 1 fimbriae expression.

CONCLUSIONS

Although hemolysin is the main virulence factor by which E. coli causes acute prostatitis, the association between hemolysin and biofilm formation may result in increased ability of E. coli strains to persist in the prostate.

Trials of bioremediation on a beach affected by the heavy oil spill of the Prestige

The objective of this study was to assess the efficiency of several bioremediation products in accelerating the in situ biodegradation of the heavy fuel oil spill of the Prestige. Trials of bioremediation were conducted in sand, rocks and granite tiles on the beach of Sorrizo (A Coruña, NW Spain) that was polluted by the spill. Neither the added microorganisms nor the nutrients significantly enhanced the degradation rate of the fuel oil in rocks, granite tiles or sand. PAH degradation up to 80% was determined in sand and tiles. In tiles the oxygen content of the residual oil increased from 1.6% up to 8% in 90 days, which could be explained by the accumulation of products coming from the partial oxidation of the hydrocarbons. Eighteen months after the spill, the rocks of the beach were still coated by a black layer of weathered fuel oil. For this reason an oleophilic product, sunflower biodiesel was tested on a rock. The application of biodiesel accelerated the gradually clean-up of the polluted surface and could also accelerate the degradation of the residual oil.