•Authors propose MILP approach for optimal cable routing in an onshore wind farm.•The novelty in the proposed algorithm is reliability assessment of the proposed network. Based on the suggested ...outline of the network, the failure rate as well as the cost of lost energy production for every wind turbine within the farm is updated.•The algorithm supports the optimal selection among different cable options, with different features, prices and capacities. The algorithm also takes into account the calculation of steady-state voltage at the point of connection (POC) and thus, accounts effect of power quality in the network.•The proposed algorithm is tested on an actual distribution model including a wind farm. The algorithm gives optimal solution for all 12 case scenarios that have been tested.
Designing an onshore wind farm is a complex planning process that requires various stages to be completed. The prime focus of this work is to assist planners and experts in finding the optimal cable layout of the onshore wind farm. The optimization algorithm is designed using mixed integer linear programming (MILP). The MILP algorithm takes into account system reliability, power transfer capacities and power quality issue. The novelty in this optimization algorithm is to simultaneously minimize cable installation cost and the cost of lost energy production and therefore maximize the reliability of the system. Additionally, the algorithm supports the optimal selection among different cable options, with different features, prices and capacities. By calculating voltage increase at the point of connection (POC), power quality issue is considered as well. The designed algorithm provides optimal results for four different wind farm layouts. Every layout is tested for three different case scenarios, where different number and type of cables are considered. The results show that more cable options contribute in lowering the total costs. Moreover, cables with higher capacity can help in improving the power quality issue.
Distribution utilities aim to operate and plan their network in a secure and economical way. The prime focus of this work is to assist utilities by developing a new integrated approach which ...considers the impacts of system reliability in distribution system planning (DSP). This approach merges different problems together and solves them in a two-stage process, as follows: 1. cable routing and optimal location and number of switching devices (circuit breakers and reclosers); 2. optimal location and number of tie switches. Moreover, the possibility of installing different cable options, with different prices and capacities, is included. The optimization algorithm is designed using mixed-integer programming (MIP). The developed algorithm analytically evaluates relationships between different components in the system and dynamically updates reliability indices, failure rate and restoration time, of every node in the system. This approach has been tested on two distribution systems. Despite the complexity and the exhaustiveness of the problem, MIP converges and provides the optimal solution for every studied scenario. The results show that an integrated approach enables utilities to obtain more comprehensive solutions. Moreover, by understanding the impact of parameter variation enables utilities to categorize their priorities in the decision making process and optimally invest in distribution network with respect to reliability.
Fault location methods are crucial for reducing fault restoration time, and thus improving a network’s system average interruption duration index (SAIDI) and customer outage cost. Resonant-earthed ...systems pose problems for traditional fault location methods, leading to poor accuracy and a need for additional complexity. In this context, methods that detect fault direction (fault-passage indicators, FPI) at multiple points in the network may show advantages over a central distance-estimation method using fault locators (FL) of poor accuracy. This paper includes a comparative study of these two major fault location methods, comparing the reliability benefit from a varied number of FPIs or a central method. The optimal placement of the fault locating devices is found by formulating a mixed-integer linear programming (MILP) optimization approach that minimizes both outage and investment costs and assesses SAIDI. This approach has been tested on an example distribution system. However, to justify the universality of the algorithm, the RBTS reliability test system has also been analysed. The comparison of location methods and placement method of FPIs are useful for reliability centred planning of resonant-earthed distribution systems where fault location is to be used. Results show that a small number of FPIs that give accurate identification of direction may give more cost effective increase in reliability than a distance estimate by FL with typical levels of inaccuracy.
Shortly before the mass mortality event of the noble pen shell (
) population in the south-eastern Adriatic coast, two rapidly growing
strains CVI_P3
(DSM 114013 T, ATCC TSD-295 T) and CVI_P4 were ...obtained from the organs of individual mollusks during the regular health status monitoring.
The strains were identified as members of the genus
using basic phenotypic characteristics, genus-specific PCR assays targeting the
and 16S rRNA genes and the commercial hybridization kit GenoType Mycobacterium CM (Hain Lifescience, Germany). MALDI-TOF mass spectrometry did not provide reliable identification using the Bruker Biotyper Database.
Genome-wide phylogeny and average nucleotide identity (ANI) values confirmed that the studied strains are clearly differentiated from their closest phylogenetic relative
and other validly published
species (ANI ≤ 85.0%). The type strain CVI_P3
was further characterized by a polyphasic approach using both phenotypic and genotypic methods. Based on the phenotypic, chemotaxonomic and phylogenetic results, we conclude that strains CVI_P3
and CVI_P4 represent a novel species, for which the name
sp. nov. is proposed.
Cats are the primary reservoirs of the bacterium Bartonella henselae, the main cause of cat-scratch disease in humans. The main vector of the bacterium is the cat flea, Ctenocephalides felis. In ...southeastern Europe, data are lacking on the prevalence of B. henselae infection in cats, the strains of B. henselae involved and the risk factors associated with the infection.
Blood samples collected in ethylenediaminetetraacetic acid-containing tubes from 189 domestic cats (156 pet cats and 33 stray cats) from Zagreb, the capital city of Croatia, and 10 counties throughout Croatia were cultured for Bartonella spp. Following culture, bacterial isolates were genotyped at eight loci after using PCR to amplify 16S ribosomal RNA (rRNA) and the internal transcribed spacer region between the 16S and 23S rRNA sequences. Univariate and multivariate logistic regression were used to identify risk factors for B. henselae infection in cats.
Bartonella spp. was detected in 31 cats (16.4%), and subsequent genotyping at the eight loci revealed B. henselae in all cases. Thirty complete multilocus sequence typing profiles were obtained, and the strains were identified as four sequence types that had been previously reported, namely ST5 (56.7%), ST6 (23.3%), ST1 (13.3%) and ST24 (3.3%), as well as a novel sequence type, ST33 (3.3%). The univariate analysis revealed a significantly higher risk of B. henselae infection in cats residing in coastal areas of Croatia (odds ratio OR 2.592, 95% confidence interval CI 1.150-5.838; P = 0.0191) and in cats with intestinal parasites (OR 3.207, 95% CI 1.088-9.457; P = 0.0279); a significantly lower risk was identified in cats aged > 1 year (OR 0.356, 95% CI 0.161-0.787; P = 0.0247) and in cats sampled between April and September (OR 0.325, 95% CI 0.147-0.715; P = 0.005). The multivariate analysis that controlled for age showed a positive association with the presence of intestinal parasites (OR 4.241, 95% CI 1.243-14.470; P = 0.0119) and coastal residence (OR 2.567, 95% CI 1.114-5.915; P = 0.0216) implying increased risk of infection, and a negative association with sampling between April and September (OR 0.379, 95% CI 0.169-0.848; P = 0.018) implying a decreased risk of infection. After controlling for the season, an increased risk of infection remained for the coastal region (OR 2.725, 95% CI 1.200-6.186; P = 0.012).
Bartonella henselae is prevalent throughout Croatia and is a public health threat. Environmental and host factors can significantly affect the risk of infection, and these should be explored in more detail. The presence of intestinal parasites highlights the need to eliminate the flea vector, Ctenocephalides felis, as the most effective approach to control infections in cats and humans.
The bacterial species
is the most common causative agent of mastitis in cows in most countries with a dairy industry. The prevalence of infection caused by
ranges from 2% to more than 50%, and it ...causes 10-12% of all cases of clinical mastitis.
The objective was to analyze 237 strains of
isolated from the milk of cows with subclinical mastitis regarding the
,
and
genes and to perform
and multi-locus sequence typing (MLST).
Sequencing amplified gene sequences was conducted at Macrogen Europe. Ridom StaphType and BioNumerics software was used to analyze obtained sequences of
and seven housekeeping genes.
The
fragment was present in 204 (86.1%) of strains, while
and
gene were detected in 10 strains, and the
gene was not detected.
typing successfully analyzed 153 tested isolates (64.3%), confirming 53
types, four of which were new types. The most frequent
type was t2678 (14%). MLST typed 198 (83.5%) tested strains and defined 32 different allele profiles, of which three were new. The most frequent allele profile was ST133 (20.7%). Six groups (G) and 15 singletons were defined.
Taking the number of confirmed
types and sequence types (STs) into account, it can be concluded that the strains of
isolated from the milk of cows with subclinical mastitis form a heterogenous group. To check the possible zoonotic potential of isolates it would be necessary to test the persons and other livestock on the farms.
The bacterial genus Bartonella is distributed worldwide and poses a public health risk. Cat-scratch disease caused by B. henselae in Croatia was first described in 1957. It is present throughout the ...country: a survey of serum samples from 268 Croatian patients with lymphadenopathy showed that 37.7% had IgG antibodies. Despite this prevalence, we are unaware of reports of Bartonella culturing from infected humans or cats in Croatia or elsewhere in southeast Europe.
Here we describe the diagnosis of a 12-year-old child with lymphadenopathy in Croatia with cat-scratch disease based on antibody detection and clinical signs, and the subsequent culturing and genotyping of B.henselae from the cat's blood. The B. henselae isolate was grown on different blood agar plates and its identity was confirmed based on polymerase chain reaction (PCR) amplification of 16S ribosomal deoxyribonucleic acid (16S rDNA) and sequencing. Multi-locus sequence typing (MLST) identified the strain genotype as sequence type 5, commonly found zoonotic B. henselae strain in cats. The child recovered after azithromycin therapy, and B. henselae in the cat was eliminated within three months after doxycycline treatment.
This is, to our knowledge, the first report of B. henselae culturing and MLST-based genotyping from cat's blood in southeast Europe. Our ability to detect B. henselae in blood through culturing but not PCR suggests that the prevalence of infected cats with low bacteremia is very high, suggesting the need to develop faster, more sensitive detection assays.
Inferring the microbiota diversity of helminths enables depiction of evolutionarily established ecological and pathological traits that characterize a particular parasite-host interaction. In turn, ...these traits could provide valuable information for the development of parasitosis control and mitigation strategy. The parasite Anisakis pegreffii (Nematoda: Anisakidae) realizes the final stage of its life-cycle within gastric chambers of aquatic mammals, causing mild-to-moderate granulomatous gastritis with eosinophilic infiltrate, to severe ulcerative gastritis with mixed inflammatory infiltrate, often associated with bacterial colonies. However, its interaction with the host microbiota remains unknown, and might reveal important aspects of parasite colonization and propagation within the final host.
MySeq Illumina sequencing was performed for the 16S rRNA gene from microbiota isolated from larvae, and uterus and gut of adult A. pegreffii parasitizing stranded striped dolphins (Stenella coeruleoalba). To assess the potential presence of Brucella ceti within isolated microbiota, Brucella-targeted real-time PCR was undertaken. In addition, TEM of the gastrointestinal tract of the infective third-stage (L3) and transitioning fourth-stage larvae (L4) was performed to characterize the morphological differences and the level of larval feeding activity.
In total, 230 distinct operational taxonomic units (OTUs) were identified across all samples (n = 20). The number of shared taxa was lower than the number of taxa found specifically in each parasite stage or organ. The dominant taxon was Mycoplasmataceae (genus Mycoplasma) in the gut and uterus of adult A. pegreffii, whereas Fusobacteriaceae (genus Cetobacterium) was the most abundant in 40% of larvae, alongside Mycoplasmataceae. No B. ceti DNA was detected in any of the microbiota isolates. TEM revealed differences in gut ultrastructure between L3 and L4, reflecting a feeble, most likely passive, level of feeding activity in L3.
Microbiota from L3 was more related to that of the gut rather than the uterus of adult A. pegreffii. Taxa of the larval microbiota showed qualitative and quantitative perturbations, likely reflecting the propagation through different environments during its life-cycle. This suggests an ontogenetic shift in the alpha and beta diversity of microbial communities from uterus-derived towards cetacean-derived microbiota. Although TEM did not reveal active L3 feeding, microbiota of the latter showed similarity to that of an actively feeding adult nematode.
A novel Brucella strain closely related to Brucella (B.) melitensis biovar (bv) 3 was found in Croatian cattle during testing within a brucellosis eradication programme.
Standardised serological, ...brucellin skin test, bacteriological and molecular diagnostic screening for Brucella infection led to positive detection in one dairy cattle herd. Three isolates from that herd were identified to species level using the Bruce ladder method. Initially, two strains were typed as B. melitensis and one as B. abortus, but multiplex PCR based on IS711 and the Suis ladder showed that all of them to belong to B. melitensis, and the combination of whole-genome and multi-locus sequencing as well as Multi-Locus Variable numbers of tandem repeats Analysis (MLVA) highlighted a strong proximity within the phylogenetic branch of B. melitensis strains previously isolated from Croatia, Albania, Kosovo and Bosnia and Herzegovina. Two isolates were determined to be B. melitensis bv. 3, while the third showed a unique phylogenetic profile, growth profile on dyes and bacteriophage typing results. This isolate contained the 609-bp omp31 sequence, but not the 723-bp omp31 sequence present in the two isolates of B. melitensis bv. 3.
Identification of a novel Brucella variant in this geographic region is predictable given the historic endemicity of brucellosis. The emergence of a new variant may reflect a combination of high prevalence among domestic ruminants and humans as well as weak eradication strategies. The zoonotic potential, reservoirs and transmission pathways of this and other Brucella variants should be explored.
•Resistance is prevalent among slow growing nontuberculous mycobacteria from animals.•Nearly all isolates showed multidrug resistance.•Humans are at risk of zoonosis that may be difficult to treat ...with current therapy.
Non-tuberculous mycobacteria are opportunistic pathogens that cause disease mainly in immunocompromised hosts. The present study assessed the prevalence of antibiotic resistance among such mycobacteria from domestic and wild animals in Croatia sampled during several years within a national surveillance program.
A total of 44 isolates belonging to nine slow-growing species were genotyped and analyzed for susceptibility to 13 antimicrobials often used to treat non-tuberculous mycobacterial infections in humans.
Most prevalent resistance was to moxifloxacin (77.3%), doxycycline (76.9%), and rifampicin (76.9%), followed by ciprofloxacin (65.4%), trimethoprim-sulfamethoxazole (65.4%), and linezolid (61.4%). Few isolates were resistant to rifabutin (7.7%) or amikacin (6.8%). None of the isolates was resistant to clarithromycin. Nearly all isolates (86.4%) were resistant to multiple antibiotics.
Our findings suggest substantial risk that human populations may experience zoonotic infections with non-tuberculous mycobacteria that will be difficult to treat using the current generation of antibiotics. Future work should clarify how resistance emerges in wild populations of non-tuberculous mycobacteria.
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