Epidemiology and impact of methicillin-sensitive Staphylococcus aureus with ß-lactam antibiotic inoculum effects in adults with cystic fibrosis.

Staphylococcus aureus is the most prevalent cystic fibrosis (CF) pathogen. Several phenotypes are associated with worsened CF clinical outcomes including methicillin-resistance and small-colony-variants. The inoculum effect (IE) is characterized by reduced ß-lactam susceptibility when assessed at high inoculum. The IE associates with worse outcomes in bacteremia and other high-density infections, and may therefore be relevant to CF. The prevalence of IE amongst a CF cohort (age ≥18 years), followed from 2013 to 2016, was investigated. Yearly methicillin-sensitive S. aureus (MSSA) isolates were screened at standard (5 × 105 CFU/mL) and high (5 × 107 CFU/mL) inoculum against narrow-spectrum anti-Staphylococcal ß-lactams and those with anti-pseudomonal activity common to CF. A ≥ 4-fold increase in minimum inhibitory concentration between standard and high inoculum defined IE. Isolates underwent blaZ sequencing and genotyping and were compared against published genomes. Fifty-six percent (99/177) of individuals had MSSA infection. MSSA was observed at ≥105 CFU/mL in 44.8% of entry sputum samples. The prevalence of the IE was 25.0%-cefazolin; 13.5%-cloxacillin; 0%-meropenem; 1.0%-cefepime; 5.2%-ceftazidime; and 34.4%-piperacillin-tazobactam amongst baseline MSSA isolates assessed. blaZ A associated with cefazolin IE (P = 0.0011), whereas blaZ C associated with piperacillin-tazobactam IE (P < 0.0001). Baseline demographics did not reveal specific risk factors for IE-associated infections, nor were long-term outcomes different. Herein, we observed the IE in CF-derived MSSA disproportionally for cefazolin and piperacillin-tazobactam and this phenotype strongly associated with underlying blaZ genotype. The confirmation of CF being a high density infection, and the identification of high prevalence of MSSA with IE in CF supports the need for prospective pulmonary exacerbation treatment studies to understand the impact of this phenotype.

Evaluation of chitosan salt properties in the production of AgNPs materials with antibacterial activity.

In this study, water-soluble chitosan salts (chitosan amine sulfopropyl salts) were prepared from chitosan samples with different molecular weights and deacetylation degrees. These soluble-in-water polymer salts allowed us to produce, in an eco-friendly and facile method, silver nanoparticles (AgNPs) with better control on size and polydispersity, even at large silver concentrations than their corresponding chitosan sample. Chitosan salt-based materials (films and scaffolds) were analyzed in terms of antibacterial properties against Staphylococcus aureus ATCC23915 or Pseudomonas aeruginosa ATCC 27853. 3D scaffolds enhanced the effect of the chitosan-AgNPs combination compared to the equivalent films.

Effect of oxygen injection in a reclaimed wastewater pipeline on the microbiological quality of water.

In this work the influence of oxygen injection on the inactivation of microbiological indicators during reclaimed wastewater transportation was studied. Experiments were carried out in a completely filled gravity pipe (62 km long), at two different periods of the year and with three different oxygen doses (7, 15 and 30 mg L(-1)). Microbiological parameters studied were faecal coliforms, Escherichia coli, enterococci and somatic coliphages. As a consequence of the oxygen injection, a significant inactivation of the microbiological parameters was observed during the aerobic stretch of the pipe. Later, once the oxygen had been consumed, inactivation stopped and even a slight regrowth of the microbial population took place. Inactivations were within the range of 0.6-1.0 log10 units, in most cases. No significant differences between inactivations for the different microbiological parameters were found, except for the somatic coliphages. A relationship between the inactivation degree and oxygen dose and organic matter content was observed. The biofilm played an important role in the inactivation process. The injection of oxygen contributes to improving the microbiological quality of reclaimed wastewater during its transport by pipelines, helping to diminish the subsequent on-site disinfection requirements.

Variation in blubber cortisol levels in a recovering humpback whale population inhabiting a rapidly changing environment.

Glucocorticoids are regularly used as biomarkers of relative health for individuals and populations. Around the Western Antarctic Peninsula (WAP), baleen whales have and continue to experience threats, including commercial harvest, prey limitations and habitat change driven by rapid warming, and increased human presence via ecotourism. Here, we measured demographic variation and differences across the foraging season in blubber cortisol levels of humpback whales (Megaptera novaeangliae) over two years around the WAP. Cortisol concentrations were determined from 305 biopsy samples of unique individuals. We found no significant difference in the cortisol concentration between male and female whales. However, we observed significant differences across demographic groups of females and a significant decrease in the population across the feeding season. We also assessed whether COVID-19-related reductions in tourism in 2021 along the WAP correlated with lower cortisol levels across the population. The decline in vessel presence in 2021 was associated with a significant decrease in humpback whale blubber cortisol concentrations at the population level. Our findings provide critical contextual data on how these hormones vary naturally in a population over time, show direct associations between cortisol levels and human presence, and will enable comparisons among species experiencing different levels of human disturbance.

Immuno-enzymatic evaluation of the recombinant TSSA-II protein of Trypanosoma cruzi in dogs and human sera: a tool for epidemiological studies.

The rTSSA-II (recombinant Trypomastigote Small Surface II) antigen was evaluated by ELISA to detect anti-Trypanosoma cruzi antibodies in sera from naturally infected dogs and humans. For this evaluation ELISA-rTSSA-II was standardized and groups were classified according to the results obtained through xenodiagnosis, ELISA and PCR. Sensitivity (Se), Specificity (Sp), Kappa index (KI) and area under curve (AUC) were determined. The Se was determined by using 14 sera from dogs infected with T. cruzi VI (TcVI) whereas Sp was determined by using 95 non-chagasic sera by xenodiagnosis, ELISA-Homogenate and PCR. The performance of ELISA-rTSSA-II in dog sera was high (AUC=0·93 and KI=0·91). The Se was 92·85% (1 false negative) and Sp was 100%. Two sera from dogs infected with TcI and 1 with TcIII were negative. For patients infected with T. cruzi, reactivity was 87·8% (36/41), there was only 1 indeterminate, and Sp was 100%. Fifty-four sera from non-chagasic and 68 sera from patients with cutaneous leishmaniasis did not react with rTSS-II. ELISA-rTSSA-II showed a high performance when studying sera from naturally infected dogs and it also presented 100% Sp. This assay could be an important tool to carry out sero-epidemiological surveys on the prevalence of T. cruzi circulating lineages in the region.

Association of Candida albicans and Cbp+ Streptococcus mutans with early childhood caries recurrence.

Early childhood caries (ECC) recurrence occurs in approximately 40% of treated cases within one year. The association of Streptococcus mutans and Candida albicans with the onset of ECC is well known. Also, S. mutans strains harboring collagen-binding proteins (Cbps) avidly bind to collagen-rich dentin and are linked to increased caries risk. Here, we investigated the presence of Cbp+ S. mutans and C. albicans in saliva and dental plaque of children with varying caries statuses, and their salivary microbiome. In this cross-sectional study, 143 children who were caries-free (n = 73), treated for ECC with no signs of recurrence after 6 months (n = 45), or treated for ECC and experiencing recurrence within 6 months following treatment (n = 25) were enrolled. Co-infection with C. albicans and S. mutans, especially Cbp+ S. mutans, was strongly associated with caries recurrence. Subjects of the recurrence group infected with Cbp+ S. mutans showed a greater burden of Candida spp. and of Mutans streptococci in dentin than those infected with Cbp- strains. Salivary microbiome analysis revealed that Streptococcus parasanguinis was overrepresented in the caries recurrence group. Our findings indicate that Cbp+ S. mutans and C. albicans are intimately associated with caries recurrence, contributing to the establishment of recalcitrant biofilms.

Esterification and modification of [1-14C] n-3 and n-6 polyunsaturated fatty acids in pikeperch (Sander lucioperca) larvae reared under linoleic or α-linolenic acid-based diets and variable environmental salinities.

To elucidate the in vivo endogenous ability of pikeperch (Sander lucioperca) larvae to deacylate and reacylate phospholipids and to elongate and desaturate PUFAs, 20 days post hatch (DPH) fish were incubated with either [1-14C]20:4n-6 bound to PC and PE, or with free [1-14C]-labelled fatty acids (18:2n-6, 18:3n-3, 20:4n-6, 20:5n-3 and 22:6n-3). The modulation capacity of both low LC-PUFAs but high 18C PUFAs precursors dietary supply and increasing salinity on larval fatty acid metabolic pathways was also investigated. [1-14C]DHA was incorporated into larval tissues to a lower extent than [1-14C]ARA or [1-14C] EPA. [1-14C]ARA was significantly less abundant in larval tissues when provided bound to PE than when esterified into PC, indicating that PC is a better phospholipid source to provide LC-PUFA to pikeperch larvae. Radioactivity was mainly recovered into phospholipids, especially that of the three LC-PUFAs ARA, EPA and DHA. All substrates were primarily incorporated into PC except [1-14C]ARA which significantly did into PI. Both [1-14C]EPA and [1-14C]DHA showed a similar esterification pattern into lipid classes: PC > PE > PI > TAG, with [1-14C]DHA presenting the highest esterification into PE of all radiolabelled compounds (26.3% vs 3.6-14.2%). Although higher rearing salinities tended to increase ∆6 desaturase activity, no radioactivity from [1-14C]18:2n-6 or [1-14C]18:3n-3 was detected in ARA or EPA, proving a deficiency of Δ5 activity and the inability of pikeperch to biosynthesize DHA. This work provides novel information on the lipid metabolism of pikeperch at early development necessary for the design of live prey enrichment protocols and dietary formulations adapted to larval metabolic capabilities.

Functional diversification of teleost Fads2 fatty acyl desaturases occurs independently of the trophic level.

The long-chain (≥C20) polyunsaturated fatty acid biosynthesis capacity of fish varies among species, with trophic level hypothesised as a major factor. The biosynthesis capacity is largely dependent upon the presence of functionally diversified fatty acyl desaturase 2 (Fads2) enzymes, since many teleosts have lost the gene encoding a Δ5 desaturase (Fads1). The present study aimed to characterise Fads2 from four teleosts occupying different trophic levels, namely Sarpa salpa, Chelon labrosus, Pegusa lascaris and Atherina presbyter, which were selected based on available data on functions of Fads2 from closely related species. Therefore, we had insight into the variability of Fads2 within the same phylogenetic group. Our results showed that Fads2 from S. salpa and C. labrosus were both Δ6 desaturases with further Δ8 activity while P. lascaris and A. presbyter Fads2 showed Δ4 activity. Fads2 activities of herbivorous S. salpa are consistent with those reported for carnivorous Sparidae species. The results suggested that trophic level might not directly drive diversification of teleost Fads2 as initially hypothesised, and other factors such as the species' phylogeny appeared to be more influential. In agreement, Fads2 activities from P. lascaris and A. presbyter were similar to their corresponding phylogenetic counterparts Solea senegalensis and Chirostoma estor.

A longitudinal characterization of the Non-Cystic Fibrosis Bronchiectasis airway microbiome.

A diverse microbiota exists within the airways of individuals with non-cystic fibrosis bronchiectasis (nCFB). How the lung microbiome evolves over time, and whether changes within the microbiome correlate with future disease progression is not yet known. We assessed the microbial community structure of 133 serial sputa and subsequent disease course of 29 nCFB patients collected over a span of 4-16 years using 16S rRNA paired-end sequencing. Interestingly, no significant shifts in the microbial community of individuals were observed during extended follow-up suggesting the microbiome remains relatively stable over prolonged periods. Samples that were Pseudomonas aeruginosa culture positive displayed markedly different microbial community structures compared to those that were positive for Haemophilus influenzae. Importantly, patients with sputum of lower microbial community diversity were more likely to experience subsequent lung function decline as defined by annual change in ≥-1 FEV1% predicted. Shannon diversity values <1 were more prevalent in patients with FEV1 decline (P = 0.002). However, the relative abundance of particular core microbiota constituents did not associate with risk of decline. Here we present data confirming that the microbiome of nCFB individuals is generally stable, and that microbiome-based measurements may have a prognostic role as biomarkers for nCFB.

The effect of preparation processes on the physicochemical characteristics and antibacterial activity of chitooligosaccharides.

The bioactivities of chitooligosaccharides are markedly influenced by the degree of acetylation, degree of polymerization or molecular weight and pattern of acetylation. Thus, it is crucial to identify reproducible processes that will give rise to well-defined chitooligosaccharides and establish methods for their posterior physicochemical characterization in order to advance in the knowledge of their bioactivity. Chitooligosaccharides were prepared by two different processes. The first used chitosanase enzymatic hydrolysis and the second consisted of a two-step procedure based on chemical hydrolysis followed by chitosanase hydrolysis. Chitooligosaccharides produced in the second process were composed of 63 % of fully deacetylated sequences and inhibited the growth of Escherichia coli and Listeria monocytogenes. Better antibacterial activity was found for those obtained in the first process composed of 27 % of fully deacetylated sequences. Therefore, a low percentage of free amino groups and the presence of acetylated sequences are necessary in these molecules to exert good antibacterial capacity.

[Frequency of diagnosis and clinic presentation of glomerulopathies in Uruguay]. / Frecuencia de diagnóstico y de presentación clínica de las glomerulopatías en el Uruguay.

UNLABELLED: The Uruguayan Registry of Glomerulopathies began its activity in 1974 and since 1985 is a national registry. The aim of this report is to analyze the incidence and the variations in frequencies of the histological diagnosis and clinical presentation during the 1980-2003 period. PATIENTS AND METHODS: From the 2,058 patients with renal biopsy in the whole period, we analyzed the histological diagnosis and the following data has been collected when the patients were registered: age, gender, clinical syndrome, proteinuria, hematuria, serum creatinine, blood pressure and time from the first symptom. Four periods of registry entry were considered: 1980-1989, 1990-1994, 1995-1999 and 2000-2003. Chi-square and Student test for independent samples were used to evaluate the differences among the variables frequencies in the four periods. RESULTS: The incidence of registered glomerulopathies per million population (pmp) increased from 13 (1980-1989) to 43 (2000-2003). In the 2000-2003 period, the incidences pmp were: primary glomerulopathy (PG), 25.3 and secondary glomerulopathy, 14.2. The highest incidences pmp were: focal and segmental glomeruloesclerosis (FSGS) 6.4; vasculitis 5.4; lupus nephritis 4.6; minimal change disease (MCD) 4.6; IgA nephropathy (IgAN) 4.5; and membranous nephropathy (MN) 4.0. The most frequent PG were the FSGS (29.3%) and the MCID (19.6%). The FSGS frequency decreased from 36.3% in 1995-1999 to 19.1% in 2000-2003. The IgAN frequency increased from 5.2% in 1980-1989 to 17.5% in 2000-2003. Nephrotic syndrome was the most frequent clinical presentation; its frequency was over 30% in the four periods. Asymptomatic urinary abnormality frequency increased from 14.0% in 1980-1989 to 22.7% in 2000-2003. The frequency of serum creatinine under 1.5 mg/dl, increased from 42.2% in 1980-1989 to 67.2% in 2000-2003 (p = 0.001). The frequency of serum creatinine over 6.0 mg/dl, decreased from 19.3% in 1990-1994 to 7.2% in 2000-2003. The percentage of patients referred since the first month of the apparent onset of the disease increased from 24.0% in 1980-1989 to 40.1% in 2000-2003 (p < 0.001). CONCLUSIONS: In Uruguay, the incidence of glomerulopathies with histological diagnosis has increased and the frequency of the different types has changed. Several indicators seem to show that the reference of patients to the nephrologist tended to be earlier in the last years.

Treatment of congenital Chagas' disease diagnosed and followed up by the polymerase chain reaction.

In 1991 and 1992, a prenatal screening of Trypanosoma cruzi infection was carried out using ELISA and indirect immunofluorescence techniques. A total of 840 blood samples from pregnant women, obtained at the Maternity Ward of the Hospital de Clínicas, National University of Asunción (Asunción, Paraguay), and 1,022 samples from the Regional Hospital of the San Pedro Department of Paraguay were examined. It was observed that 7.7% and 10.5%, respectively, of the pregnant women were serologically positive for infection with T. cruzi. When blood samples obtained from newborns on the day of birth or, at the most, on the first few days afterwards were examined by direct microscopic observation, an incidence of congenital transmission of 3% was found. These results are consistent with those of neighboring countries. When a serologic follow-up was conducted on the newborns until six months of age, the incidence of congenital transmission reached 10%. The same incidence rate was obtained when the samples collected during the first days after birth were examined by the polymerase chain reaction (PCR). Fifty-eight infants born to seropositive mothers were followed-up, two of which were positive by direct microscopic observation at birth, and four who were PCR-positive, but microscopy-negative at birth. None of the infants were positive for IgM at birth. The infected babies were treated with benznidazole and were followed-up by serology and PCR for four years. We conclude that the PCR has a clear advantage over conventional techniques for the early detection of congenital transmission of T. cruzi infection, and for monitoring infants undergoing chemotherapy.

Photon output factor calculation from the inverse of the sector-integration equation.

A method to predict rectangular field output factors (OFs) of photon open beams for the Saturne 41 linear accelerator has been developed. The procedure is similar to the sector-integration method but the radiotherapy quantities corresponding to circular fields (circular functions) are calculated from one-dimensional OFs. In this case the one-dimensional OFs are defined as rectangular field OFs, where one side remains constant and equal to the maximum field size. The circular quantities are numerically obtained by inversion of the sector-integration equation which relates both the one-dimensional OFs and the circular function. Two one-dimensional OFs were used to take into account the asymmetry between the x and y collimator systems (collimator exchange effect). The resulting pair of circular functions corresponds to the x and y collimator systems, respectively. They contain all the information relative to head, air, and medium (phantom) scatter and, consequently, there is no need to account for the geometry of the head or fitting parameters. Using the sector-integration method, the OFs for any rectangular field can be calculated by integrating the obtained circular functions. To improve results, a procedure is given to account for corner collimators overlapping. Results agree with data to within approximately 0.4% at 6-15 MV photon beams. The proposed method is thus clinically acceptable for routine calculation. Furthermore, the circular function calculation algorithm could be extended to other radiotherapy quantities.

Irregular field calculation on the central beam axis of photon beams using sector-integration.

A method is proposed for calculation of irregular field factors on the central beam axis and homogeneous medium for x-ray beams. The irregular field factor is introduced as the ratio of the output of a field with and without blocks on the central beam axis. The algorithm is based on the sector-integration method and the circular field quantities are calculated from in-phantom measurements. These circular field quantities are the output per beam monitor unit for circular fields defined by a hypothetical secondary collimator and reduced to a circular field by blocking. A derivation of the sector-integration equation is given from first principles. As it is shown, the circular field quantities are evaluated from data measured for rectangular, block shaped fields. Such quantities contain all beam components, including photons scattered from the blocks, the block tray, and photons scattered in the phantom. Consequently, the so called primary and secondary beam components are readily incorporated in this approach. Once the circular field quantities have been determined from rectangular field data, the irregular field factors for other geometry can be calculated. Irregular field factors for square, rectangular and circular block-shaped fields were calculated for 6 MV photon beams and compared with measured values. The results agree within 0.7%, even for heavy blocked field cases, i.e., a 40 x 40 cm2 collimator field blocked to a 5 x 5 cm2 field. The method was tested for a particular source to surface distance, depth, phantom composition, and source to block distance. Calculation of irregular field factors in another set up conditions requires the measurement of the appropriate input data.

Mutagenicity, insecticidal and trypanocidal activity of some Paraguayan Asteraceae.

The insecticidal, moulting inhibition and trypanocidal effects of crude extracts of 7 Paraguayan Asteraceae were evaluated on Triatoma infestans and bloodstream forms of Trypanosoma cruzi, respectively. Both mutagenicity and toxicity were evaluated by sister chromatid exchange (SCE) in human peripheral lymphocyte culture and by the lethality test of Artemia salina. The ethanolic extracts from Chromolaena christieana (stem and bark), Achyrocline satureoides (leaves and flowers) and Mikania cordifolia (root and stem), at a concentration of 250 micrograms/ml, showed the highest percentage of lysis on bloodstream forms of Trypanosoma cruzi. The extracts of Chromolaena christieana and Achyrocline satureoides also presented high mutagenic and toxic capacity when they were evaluated by the SCEs assay and Artemia salina test, respectively. Insecticidal activity was only observed in the hexane extract of flowers of Achyrocline satureoides (45% of mortality), when 0.05 microgram of crude concentration was applied on Triatoma infestans. The ethanolic extracts of stem from Mikania cordifolia and Vernonia brasiliana inhibited the moulting of Triatoma infestans when it was compared with their controls. Since no ethnobotanical information on these plants has been found related to similar use in Paraguay, our findings suggest, for the first time, the potential anti-trypanocidal and moulting inhibition of these Asteraceae.

Pathogenicity of Pratylenchus coffeae, Scutellonema bradys, Meloidogyne incognita, and Rotylenchus reniformis on Dioscorea rotundata.

Low populations (200 specimens per plant) of Pratylenchus cofl'eae, Scutellonema bradys, Meloidogyne incognita, and Rotylenchulus reniformis stimulated the development of tops, roots, and tubers of Dioscorea rotundata "Guinea" yam. We demonstrated experimentally that P. coffeae was responsible for the deterioration in quality of the yam tuber in Puerto Rico, a condition known as a dry rot of yam. Initial populations of 600 P. coffeae, S. bradys, or M. incognita, and populations of 1,000 P. coffeae or S. bradys per plant were high enough to induce dry rot of the yam tubers. P. coffeae and S. bradys were pathogenic to yam cultivar Guinea, but M. incognita and R. reniformis did not cause necrosis or cracking of the tuber cortex in our experiments.

Effects of Pratylenchus coffeae and Scutellonema bradys alone and in combination on guinea yam (Dioscorea rotundata).

When Guinea yam, Dioscorea rotundata Poir, was inoculated with Pratylenchus coffeae and Scutellonema bradys together, there was a 53% suppression of top growth, but when plants were inoculated separately there was a 29% suppression with P. coffeae and a 21% suppression with S. bradys. The reproduction of S. bradys was greatly inhibited when both nematode species were together on the same plant in comparison with that on plants inoculated with S. bradys alone. Scutellonema bradys apparently did not affect the reproduction of P. coffeae. Storage-root quality was reduced 72% by P. coffeae but only 20% by S. bradys. The two species together resulted in a reduction in storage-root quality of 84%. Although the Guinea yam is a good host of P. coffeae and S. bradys, our results indicate that P. coffeae is responsible for most of the storage-root deterioration and dry rot of yam in Puerto Rico.

Symptomatology and Histopathology of Soybean Roots Infected by Pratylenchus scribneri and P. alleni.

Size of lesions caused by Pratylenchus scribneri on roots of 'Clark 63' soybean was correlated with nematode colony size within roots. A single nematode was capable of causing a detectable lesion. When a root became highly necrotic and shrunken, few nematodes but numerous eggs remained in the tissue. In histological sections made 5, 11, 18, and 45 d after planting, P. scribneri was located entirely within the cortex and generally was oriented longitudinally to the vascular cylinder, either outstretched in the same plane or coiled through several cells. Nematodes moved intracellularly, causing extensive rupturing of cell walls, retraction and disappearance of cytoplasm, and thickening of cell walls and necrosis of cells around feeding sites. Depth of penetration within the cortex and necrosis of cells increased with time after infection, eventually resulting in formation of cavities in the cortex and occasional secondary injury to the endodermis. Stele tissue was unaffected by feeding, and damage to the epidermis was limited to nematode entry points. Orientation of P. alleni and histopathology of its infection at 45 days were identical to those of P. scribneri, except that there was no injury to the endodermis.

Influence of temperature on population development of eight species of pratylenchus on soybean.

In a soil temperature study, population increase on 'Clark 63' soybeatt was most rapid at 30 C in Pratylenchus alleni, P. brachyurus, P. cofleae, P. neglectus, P. scribneri, and P. zeae and at 25 C in P. penetrans and P. vulnus. The last two were the only species that reproduced at 15 C. Populations of all species increased over the range of 20-30 C, except those of P. neglectus at 20 C and P. coffeae, which was not tested below 25 C. Only P. brachyurus, P. neglectus, P. scribneri and P. zeae reproduced at 35 C. At their optimum temperatures, P. scribneri exhibited the greatest population increase, 1248-fold, and P. penetrans the least, 32-fold. This is the first report of soybean as a host for P. vulnus.