Pseudomonas aeruginosa bloodstream infections in children and adolescents: risk factors associated with carbapenem resistance and mortality.

BACKGROUND: Pseudomonas aeruginosa bloodstream infections (PA-BSIs) are a serious disease and a therapeutic challenge due to increasing resistance to carbapenems. Our objectives were to describe the prevalence and risk factors associated with carbapenem resistance (CR) and mortality in children with PA-BSI. METHODS: A retrospective, multi-centre study was carried out, including patients aged <20 years with PA-BSI in four tertiary hospitals in Madrid (Spain) during 2010-2020. Risk factors for CR PA-BSIs and 30-day mortality were evaluated in a multi-variable logistic regression model. RESULTS: In total, 151 patients with PA-BSI were included, with a median age of 29 months (interquartile range: 3.5-87.1). Forty-five (29.8%) cases were CR, 9.9% multi-drug resistant and 6.6% extensively drug resistant. The prevalence of CR remained stable throughout the study period, with 26.7% (12/45) of CR mediated by VIM-type carbapenemase. Patients with BSIs produced by CR-PA were more likely to receive inappropriate empiric treatment (53.3% vs 5.7%, P<0.001) and to have been previously colonized by CR-PA (8.9% vs 0%, P=0.002) than BSIs caused by carbapenem-susceptible P. aeruginosa. CR was associated with carbapenem treatment in the previous month (adjusted odds ratio (aOR) 11.15) and solid organ transplantation (aOR 7.64). The 30-day mortality was 23.2%, which was associated with mechanical ventilation (aOR 4.24), sepsis (aOR 5.72), inappropriate empiric antibiotic therapy (aOR 5.86), and source control as a protective factor (aOR 0.16). CONCLUSION: This study shows a concerning prevalence of CR in children with PA-BSIs, leading to high mortality. Inappropriate empiric treatment and sepsis were associated with mortality. The high prevalence of CR with an increased risk of inappropriate empiric treatment should be closely monitored.

Quantitative survival of native Salmonella serovars during storage of frozen raw pork.

The quantitative survival of material contaminants of Salmonella serovars was studied in raw pork during frozen storage. Raw pork samples were obtained from public markets in Guadalajara, Mexico, and tested for Salmonella. Three positive samples were selected for survival studies in three different trials. Populations of Salmonella were determined by the most probable number (MPN) method, with isolation on bismuth sulfite agar plates. One typical colony was selected from each plate and subjected to serovar identification. Approximately 20 colonies were serotyped for each portion of frozen pork at each sampling time during storage. During frozen storage, numbers of Salmonella were reduced from 7-11 to 1.6 MPN g(-1) over a period of 22 weeks in Trial 1, from 1500 9000 to 2.5 MPN g(-1) over 42 weeks in Trial 2, and from 2000-20,000 to 20 MPN g(-1) over 78 weeks in Trial 3. The number of different Salmonella serovars identified was 10, 14 and 29 for Trials 1, 2 and 3, respectively. In Trial 3, S. agona, S. newbrunswick, S. drypool and S. anatum predominated over the other 25 serovars identified. S. agona was not only the most prevalent, but also the most abundant. At 15 weeks of storage, estimated MPNs of this serovar were 700 g(-1) of pork. Most serovars were detected sporadically; nine were isolated only once, and nine only twice. Serovars such as S. derby and S. newlands appeared only at the first sampling time, while others such as S. schwarzengrund, S. dublin and S. newport appeared only at the last sampling time. Most serovars identified in this study are commonly isolated from human clinical sources and from raw or processed foods in Mexico.

Organochlorine pesticides in wolves from Galicia.

Levels of seven organochlorine pesticides (heptachlorepoxide, dieldrin, endrin, p,p'-DDE, o-p'-DDT, p,p'-DDT, and methoxychlor) and DDE/DDT ratios were determined in spleen, liver, muscle, kidney and suprarenal from 12 wolves from three provinces of Galicia (eight male and four female). Analysis was carried out by GC-ECD. Heptachlorepoxide was in found only 25% of samples, while p,p'-DDE was the most dominant of the organochlorine compounds analyzed. DDE/DDT ratios higher than 1 were found in liver and muscle.

Application of the effects of solvent and dissolved oxygen on the determination of benzo[a]pyrene by constant-wavelength synchronous spectrofluorimetry in smoke-flavouring.

This work studies the effects of solvent and of dissolved oxygen in the determination of benzo[a]pyrene (BaP) by constant-wavelength synchronous spectrofluorimetry in smoke-flavour agents, as confirmation and quantification techniques. The wavelength of the most intense peak at the optimum excitation-emission wavelength interval (20 or 110 nm in most of nine solvents) varied by up to 5 nm, and the detection and quantification limits by a factor of up to 30. The best quantification limit was obtained with DMSO (0.09 mug l(-1)). The deoxygenation of the analyte solution decreased detection and quantification limits, by a variable factor (8-1.13 in the case of n-hexane and DMSO, respectively).

Comparison of two extraction methods for determination of PCBs and PCTs in mussels from Galicia.

We compared two extraction methods for use in GC-ECD determination of polychlorinated bi- and terphenyl contaminants (PCBs and PCTs respectively) in mussels (Mytilus galloprovincialis). Mussels spiked with standard PCB and PCT mixtures Aroclor 1260 and Aroclor 5460 were extracted with cold acetonitrile, or with 1:1 n-hexane/ dichloromethane in a Soxhlet extractor, which gave the better mean recoveries of 99.0 +/- 2.5% and 59.5 +/- 8.3% for PCBs and PCTs respectively.

Determination of polycyclic aromatic hydrocarbons in drinking and surface waters from Galicia (N.W. Spain) by constant-wavelength synchronous spectrofluorimetry.

We describe a fast, new method for determination of the joint concentration of the six polycyclic aromatic hydrocarbons (PAHs), designated by current legislation as indicators of the quality of drinking waters and surface waters intended for the abstraction of drinking waters. The limit of detection of the new method was 6 ng l(-1), its limit of quantification 20 ng l(-1), its precision (CV%) 2.48 and its recovery 94.05%. Its speed allowed rapid PAH screening of 404 samples of surface and drinking water from Galicia (N.W. Spain).