Natural product guvermectin inhibits guanosine 5'-monophosphate synthetase and confers broad-spectrum antibacterial activity

Bacterial diseases caused substantial yield losses worldwide, with the rise of antibiotic resistance, there is a critical need for alternative antibacterial compounds. Natural products (NPs) from microorganisms have emerged as promising candidates due to their potential as cost-effective and environmentally friendly bactericides. However, the precise mechanisms underlying the antibacterial activity of many NPs, including Guvermectin (GV), remain poorly understood. Here, we sought to explore how GV interacts with Guanosine 5'-monophosphate synthetase (GMPs), an enzyme crucial in bacterial guanine synthesis. We employed a combination of biochemical and genetic approaches, enzyme activity assays, site-directed mutagenesis, bio-layer interferometry, and molecular docking assays to assess GV's antibacterial activity and its mechanism targeting GMPs. The results showed that GV effectively inhibits GMPs, disrupting bacterial guanine synthesis. This was confirmed through drug-resistant assays and direct enzyme inhibition studies. Bio-layer interferometry assays demonstrated specific binding of GV to GMPs, with dependency on Xanthosine 5'-monophosphate. Site-directed mutagenesis identified key residues crucial for the GV-GMP interaction. This study elucidates the antibacterial mechanism of GV, highlighting its potential as a biocontrol agent in agriculture. These findings contribute to the development of novel antibacterial agents and underscore the importance of exploring natural products for agricultural disease management.

Assessment of fish protein hydrolysate as a substitute for fish meal in white shrimp diets: Impact on growth, immune response, and resistance against Vibrio parahaemolyticus infection

This study investigated the effects of fish protein hydrolysate derived from barramundi on growth performance, muscle composition, immune response, disease resistance, histology and gene expression in white shrimp (Penaeus vannamei). In vitro studies demonstrated FPH enhanced mRNA expressions of key immune-related genes and stimulated reactive oxygen species (ROS) production and phagocytic activity in shrimp hemocytes. To evaluate the effects of substituting fish meal with FPH in vivo, four isoproteic (43 %), isolipidic (6 %), and isoenergetic diets (489 kcal/100 g) were formulated with fish meal substitution levels of 0 % (control), 30 % (FPH30), 65 % (FPH65), and 100 % (FPH100). After 8-week feeding, the growth performance of FPH65 and FPH100 were significantly lower than that of control and FPH30 (p < 0.05). Similarly, the midgut histological examination revealed the wall thickness and villi height of FPH100 were significantly lower than those of control (p < 0.05). The shrimps were received the challenge of AHPND + Vibrio parahaemolyticus at week 4 and 8. All FPH-fed groups significantly enhanced resistance against Vibrio parahaemolyticus at week 4 (p < 0.05). However, this protective effect diminished after long-period feeding. No significant difference of survival rate was observed among all groups at week 8 (p > 0.05). The expressions of immune-related genes were analyzed at week 4 before and after challenge. In control group, V. parahaemolyticus significantly elevated SOD in hepatopancreas and Muc 19, trypsin, Midline-fas, and GPx in foregut (p < 0.05). Moreover, hepatopancreatic SOD of FPH65 and FPH100 were significantly higher than that of control before challenge (p < 0.05). Immune parameters were measured at week 8. Compared with control, the phagocytic index of FPH 30 was significantly higher (p < 0.05). However, dietary FPH did not alter ROS production, phenoloxidase activity, phagocytic rate, and total hemocyte count (p > 0.05). These findings suggest that FPH30 holds promise as a feed without adverse impacts on growth performance while enhancing the immunological response of white shrimp.

First Report of Dickeya dadantii Causing Potato Blackleg in Fujian Province China

Blackleg and soft rot are harmful diseases in potato (Solanum tuberosum) caused by Pectobacterium spp. and Dickeya spp. (Czajkowski et al. 2015). The occurrence of potato blackleg was serious in potato-producing areas around Xiapu County in Fujian Province, China, in 2021 (6 ha) and 2022 (7 ha), with an incidence of approximately 5%, which reached nearly 23%. Three diseased plants were collected to isolate the pathogen. Single colonies from each sampled plant were isolated and streaked onto fresh plates. DNA from three colonies from different plants was PCR amplified with primer pair 27F/1492R (Lane 1991) for the 16S rRNA gene. Since the sequences were identical, we selected strain M2-3 for further analysis. The strain M2-3 was gram-negative, pectolytic on CVP, grew at 37°C and 5% NaCl. The bacterium was positive for phosphatase activity, erythromycin sensitivity, indole production, gelatin liquefaction, malonic utilization, and acid production from, melibiose, raffinose, and arabinose. The bacterium was negative for sucrose, α-methyl glucoside, sorbitol, trehalose, lactose, and sodium citrate (Fujimoto et al. 2018;),although sucrose and lactose did not provide the expected results, there are exception in all species. The genome of strain M2-3 was sequenced and deposited in the NCBI database under accession numbers: CP077422. An Average Nucleotide Identity (ANI) analysis showed that M2-3 clustered with other D. dadantii strains and has a 98.39% identity with D. dadantii strain DSM 18020 (CP023467). The housekeeping genes (recA, dnaX, acnA, gapA, icd, mdh, mtlD and pgi) were amplified with primer pairs designed previously(Fujimoto et al. 2018; Ma et al. 2007) and sequenced. A multilocus sequence analysis (MLSA) was performed by concatenating the 8 gene sequences and constructing a maximum likelihood phylogenetic tree using PhyloSuite version 1.2.1 (Zhang et al. 2020) and IQ-tree version 1.6.8 (Nguyen et al. 2015) software. Strain M2-3 was clustered together with Dickeya dadantii. For the pathogenicity test, three plants per treatment, totaling nine plants, were used. Bacterial suspensions (1×10^8 CFU/mL) were made in a 10mM PBS buffer. 10 μL of M2-3, D. dadantii type strain 18020 (positive control), and buffer (negative control) were injected into the plant stems near the base. Water stains appeared at the site of inoculation after 2 days and they gradually became black and rotten. The leaves became yellow and wilted, and the petiole base rotted within 5 days of inoculation completing the Koch postulate. According to average nucleotide identity and housekeeping gene sequence analysis, strain M2-3 was identified as Dickeya dadantii. Previous studies have reported several pathogens that cause potato blackleg in China, including P. atrosepticum, P. carotovorum, P. brasiliense, P. parmentieri, P. polaris, and P. punjabense (Li-ping et al. 2020; Wang et al. 2021). To the best of our knowledge, this study is the first to report potato blackleg disease caused by Dickeya dadantii in Fujian Province, China. This finding suggests that this pathogen may cause a threat to potato production in Fujian Province.

Nongonococcal tysonitis

Tyson's glands are sebaceous glands located on each side of the frenulum that communicate with the preputial sac, and their inflammation can be an infrequent complication of urethritis. We describe a rare case that presented with urethral discharge and parafrenular swelling with mucopurulent discharge a week after an unprotected sexual encounter. The patient was empirically treated with 500 mg of ceftriaxone intramuscularly and 100 mg of doxycycline every 12 h for 14 days with symptomatic resolution. The urethral swab culture and the urine polymerase chain reaction (PCR) were negative for Neisseria gonorrhoeae and Chlamydia trachomatis, therefore, and given the response to treatment, nongonococcal tysonitis was diagnosed.

An Updated View on the Cellular Uptake and Mode-of-Action of Clostridioides difficile Toxins

Research on the human gut pathogen Clostridioides (C.) difficile and its toxins continues to attract much attention as a consequence of the threat to human health posed by hypervirulent strains. Toxin A (TcdA) and Toxin B (TcdB) are the two major virulence determinants of C. difficile. Both are single-chain proteins with a similar multidomain architecture. Certain hypervirulent C. difficile strains also produce a third toxin, namely binary toxin CDT (C. difficile transferase). C. difficile toxins are the causative agents of C. difficile-associated diseases (CDADs), such as antibiotics-associated diarrhea and pseudomembranous colitis. For that reason, considerable efforts have been expended to unravel their molecular mode-of-action and the cellular mechanisms responsible for their uptake. Many of these studies have been conducted in European laboratories. Here, we provide an update on our previous review (Papatheodorou et al. Adv Exp Med Biol, 2018) on important advances in C. difficile toxins research.

Usefulness of polymerase chain reaction analysis in a case of clinically and histologically atypical nodular granulomatous secondary syphilis

We report a case of a nodular granulomatous secondary syphilis histologically resembling tuberculids in a patient with positive quantiferon test and serology for syphilis. Polymerase chain reaction (PCR) analysis led to the diagnosis. We underline the usefulness of PCR in clinically and histologically doubtful cases in order to avoid misdiagnosis and delay treatment.

Relapsing donovanosis rhyming with unexplained decline in CD4 count in a person living with HIV/AIDS: Long-term follow up and therapeutic outcome

Donovanosis is a chronic genital ulcerative disease caused by the intracellular Gram-negative bacterium Klebsiella granulomatis, reported more frequently in people living with HIV/AIDS (PLHA). Here we present a case of relapsing donovanosis in a PLHA on second line antiretroviral therapy who had episodes of transient unexplained decrease in CD4 counts associated with rapid growth of the lesion and non-responsiveness to treatment followed by clinical resolution coinciding with recovery of the CD4 count.

Population genetic diversity and dynamics of the honey bee brood pathogen Melissococcus plutonius in a region with high prevalence

European foulbrood (EFB) is a honey bee brood disease caused by the bacterium Melissococcus plutonius. Large-scale EFB outbreaks have been reported in several countries in recent decades, which entail costly sanitation measures of affected apiaries to restrict the spread of this contagious pathogen. To mitigate its impact, a better understanding of the population dynamics of the etiological agent is required. We here used multi-locus sequence typing (MLST) to infer the genetic diversity and geographical distribution of 160 M. plutonius isolates collected from EFB symptomatic honey bee colonies seven years apart. Isolates belonged to three clonal complexes (CCs) known worldwide and to 12 sequence types (STs), of which five were novel. Phylogenetic and clustering analyses showed that some of these novel sequence types have likely evolved locally during a period of outbreak, but most disappeared again. We further screened the isolates for melissotoxin A (mtxA), a putative virulence gene. The prevalence of STs in which mtxA was frequent increased over time, suggesting that this gene promotes spread. Despite the increased frequency of this gene in the population, the total number of cases decreased, which could be due to stricter control measures implemented before the second sampling period. Our results provide a better understanding of M. plutonius population dynamics and help identify knowledge gaps that limit efficient control of this emerging disease.

Modeling the impact of precautionary measures and sanitation practices broadcasted through media on the dynamics of bacterial diseases

The media has a significant contribution in spreading awareness by broadcasting various programs about prevalent diseases in the society along with the role of providing information, feeding news and educating a large mass. In this paper, the effect of media programs promoting precautionary measures and sanitation practices to control the bacterial infection in the community is modeled and analyzed considering the number of media programs as a dynamical variable. In the modeling phenomena, human population is partitioned into three classes; susceptible, infected and recovered. The disease is supposed to spread by direct contact of susceptible with infected individuals and indirectly by the ingestion of bacteria present in the environment. The growth in the media programs is considered proportional to the size of infected population and the impact of these programs on the indirect disease transmission rate and bacteria shedding rate by infected individuals is also considered. The feasibility of equilibria and their stability conditions are obtained. Model analysis reveals that broadcasting media programs and increasing its effectiveness shrink the size of infected class and control the spread of disease to a large extent.

Shrimp bacterial and parasitic disease listed in the OIE: A review

Shrimp aquaculture industry has steadily increased with demand and development of aquaculture technology. In recent years, frequent diseases have become a major risk factor for shrimp aquaculture, such as a drastically reduced the production of shrimp and causing national economic loss. Among them, shrimp bacterial diseases such as hepatopancreatic necrosis disease (AHPND) and necrotizing hepatopancreatitis (NHP-B) and parasitic disease such as Aphanomyces astaci (crayfish plague) are emerging and evolving into new types. OIE (World Organization for Animal Health) regularly updates information on diseases in the Aquatic Code and Aquatic Manual, but in-depth information on the shrimp diseases are lacking. Therefore, the purpose of this review is to provide information necessary for the response and prevention of shrimp diseases by understanding the characteristics and diagnosis of shrimp diseases designated by OIE.

OsVQ1 links rice immunity and flowering via interaction with a mitogen-activated protein kinase OsMPK6

Knocking out OsVQ1 in rice released OsMPK6 for activation and in turn promoted H₂O₂ accumulation, which repressed the expression of flowering-promoting genes, thus delaying rice flowering but enhancing disease resistance. The valine-glutamine (VQ) protein family, which contains the conserved motif FxxxVQxLTG ("x" represents any amino acid), plays a crucial role in plant growth and immunity along with mitogen-activated protein kinase (MAPK) cascades. However, only a few rice VQ proteins have been functionally characterized, and the roles of the MAPK-VQ module in rice biological processes are not fully understood. Here, we investigated the role of OsVQ1 in rice disease resistance and the control of flowering time. The OsVQ1-knock out (KO) mutants exhibited increased resistance to Xanthomonas oryzae pathovars, accumulated high levels of hydrogen peroxide (H₂O₂), and showed a late flowering phenotype under natural long-day conditions, while the OsVQ1-overexpressing plants showed phenotypes similar to that of the wild type. Further studies revealed that OsVQ1 physically interacted with and inhibited OsMPK6 activity. In addition, OsVQ1 expression was downregulated by the pathogen-induced OsMPKK10.2-OsMPK6-OsWRKY45 cascade, suggesting a feedback loop between OsVQ1 and OsMPK6. Moreover, the OsVQ1-KO/osmpk6 double-mutant exhibited increased susceptibility to X. oryzae infection and showed an early flowering phenotype, which may partially be attributed to the reduced accumulation of H₂O₂ and the consequent up-expression of flowering-promoting genes. These results suggested that the OsVQ1-OsMPK6 module was involved in rice immunity and flowering.

United Kingdom British association for sexual health and HIV national guideline for the management of epididymo-orchitis, 2020

The British Association for Sexual Health and HIV (BASHH) UK guideline for the management of epididymo-orchitis has been updated in 2020. It offers advice on diagnostic tests, treatment and health promotion principles in the effective management of epididymo-orchitis. Empirical treatment should be started in patients with objective swelling and tenderness on testicular examination. First-line empirical treatment for sexually acquired epididymo-orchitis has changed to ceftriaxone 1g intramuscularly and doxycycline. Higher dose of ceftriaxone in line with the BASHH 2018 gonorrhoea guideline ensures effective treatment of strains with reduced susceptibility. Ofloxacin or doxycycline is recommended in patients with epididymo-orchitis probably due to non-gonococcal organisms (e.g. negative microscopy for gram-negative intracellular diplococci or no risk factors for gonorrhoea identified). Where Mycoplasma genitalium is tested and identified, treatment should include an appropriate antibiotic (e.g. moxifloxacin). If enteric pathogens are a likely cause (e.g. older patient, not sexually active, recent instrumentation, men who practice insertive anal intercourse, men with known abnormalities of the urinary tract or a positive urine dipstick for leucocytes and nitrites), ofloxacin and levofloxacin are recommended. A clinical care pathway has been produced to simplify the management of epididymo-orchitis. A patient information leaflet has been developed.

Main bacterial species causing clinical disease in ornamental freshwater fish in Brazil

Bacterial diseases are common in ornamental fish, more frequently associated with ubiquitous bacteria from the aquarium environment. The disease can lead to fish mortality and cause high economic losses if not rapidly controlled. The aim of this study was to identify the main causative bacterial agents of infection in ornamental fish with different clinical signs. A total of 126 freshwater fish, from 12 families and 38 species, with clinical signs were collected in a wholesaler in São Paulo, SP, Brazil. Samples were taken from the eye, skin ulcers, kidneys, and gills, plated on MacConkey, CHROMagar Orientation, and blood agar and incubated under aerobic and anaerobic conditions. Bacterial identification was performed by MALDI-TOF mass spectrometry. From the 126 studied animals, 112 were positive for bacterial isolation. Among the positive animals, 32.1% presented infection caused by a single bacterial species, while in the remaining 67.9%, two to six different bacterial species were identified. A total of 259 bacterial strains were obtained and classified among 46 bacterial species. The species of higher frequency were Aeromonas veronii (26.3%), Aeromonas hydrophilla (16.2%), Shewanella putrefaciens (7.3%), Citrobacter freundii (8.1%), Vibrio albensis (5.8%), and Klebsiella pneumoniae (4.2%). MALDI-TOF MS showed to be a rapid method for diagnosis of bacterial disease outbreaks in ornamental fish establishments.

Current use and management of commercial fish vaccines in Korea

The aquaculture industry in Korea has grown rapidly since the 1960s, and it is a major food source. However, the expansion of aquaculture systems has increased the chances of infectious disease outbreaks, and vaccination plays an important role in commercial fish farming. This is the first comprehensive review of commercial fish vaccines in Korea. It not only provides an overview of commercially available fish vaccines and their associated approval processes and laws, but also some perspectives on research advances regarding fish vaccines in Korea. In Korea, fish vaccines are approved only after their safety and effectiveness have been verified according to the Pharmaceutical Affairs Act, and after approval, each vaccine lot must pass the national evaluation criteria. As of the end of 2019, 29 vaccines were approved for 10 fish pathogens, including both single and combination vaccines containing more than two inactivated pathogens. The approved fish vaccines consist of 2 immersion vaccines, as well as 1 intramuscular and 26 intraperitoneal vaccines, which require syringe injection. All the 29 vaccines are manufactured as formalin-inactivated vaccines; 1 is an adjuvant vaccine and 28 are non-adjuvant vaccines; 25 are bacterial vaccines, 2 are viral vaccines, 1 is a parasite vaccine, and 1 is a parasite and bacterial vaccine. In terms of the target fish species, 27 vaccines are used in the olive flounder (Paralichthys olivaceus), 1 in the starry flounder (Platichthys stellatus), and 1 in the red seabream (Pagrus major), striped beakfish (Oplegnathus fasciatus), and amberjack (Seriola quinqueradiata). This imbalance exists mostly because the olive flounder is the main farmed fish species in Korea. In 2018, 67.71 million vaccine doses were distributed following satisfactory performance in the national evaluation. They were used to vaccinate approximately 80.6% of farmed olive flounders.

Marine mammals are natural hosts of Oceanivirga salmonicida, a bacterial pathogen of Atlantic salmon

During 1992 and 1993, a bacterial disease occurred in a seawater Atlantic salmon Salmo salar farm, causing serious mortalities. The causative agent was subsequently named as Oceanivirga salmonicida, a member of the Leptotrichiaceae. Searches of 16S rRNA gene sequence databases have shown sequence similarities between O. salmonicida and uncultured bacterial clones from the digestive tracts of marine mammals. In the current study, oral samples were taken from stranded dolphins (common dolphin Delphinus delphis, striped dolphin Stenella coeruleoalba) and healthy harbour seals Phoca vitulina. A bacterium with growth characteristics consistent with O. salmonicida was isolated from a common dolphin. The isolate was confirmed as O. salmonicida, by comparisons to the type strain, using 16S rRNA gene, gyrB, groEL, and recA sequence analyses, average nucleotide identity analysis, and MALDI-TOF mass spectrometry. Metagenomic analysis indicated that the genus Oceanivirga represented a significant component of the oral bacterial microbiomes of the dolphins and seals. However, sequences consistent with O. salmonicida were only found in the dolphin samples. Analyses of marine mammal microbiome studies in the NCBI databases showed sequences consistent with O. salmonicida from the common dolphin, striped dolphin, bottlenose dolphin Tursiops truncatus, humpback whale Megaptera novaeangliae, and harbour seal. Sequences from marine environmental studies in the NCBI databases showed no sequences consistent with O. salmonicida. The findings suggest that several species of marine mammals are natural hosts of O. salmonicida.

Herpetiform aphthous genital ulcers misdiagnosed as herpes genitalis in a young male and their effective response to colchicine therapy

Genital ulceration can be a source of tremendous stress to the patient, as well as to the family members, and poses a difficult and sensitive diagnostic conundrum for the clinician. Cultural taboos and social stigmas related with the disease often result in the clinician not believing the patient’s version of history and basing the diagnosis entirely upon the clinical picture, aided by diagnostic tests. The clinicians should keep in mind that sexually transmitted infections (STIs), which can cause genital ulceration are very common, but there is a long list of non-sexually acquired causes of genital ulceration, which can lead to a diagnostic dilemma, and these should be considered before labelling the patient as suffering from a STI. We present a rare case of herpetiform genital aphthous ulcers mimicking herpes genitalis and chancroid, which was misdiagnosed repeatedly, and their effective response to treatment with colchicine on subsequent identification of the correct diagnosis.

Tolerance to ozone might impose restrictions to plant disease management in tomato

Tropospheric ozone (O₃ ) is considered a major air pollutant having negative effects on plant growth and productivity. Background concentrations are expected to rise in several regions of the world in the next 50 years, affecting plant responses to diseases, thus requiring new management strategies for food production. The effects of elevated O₃ on the severity of a bacterial disease, and the effectiveness of a chemical defence inducer, were examined in two cultivars of tomato, Roma and Moneymaker, which present different tolerance to this pollutant. The two cultivars differ in their ability to produce and accumulate reactive oxygen species (ROS) in leaf tissues. Tomato plants were challenged with a strain of Xanthomonas vesicatoria, Xv9, which is pathogenic on tomato. Ozone consistently increased severity of the disease by over 40% in both cultivars. In the more tolerant cultivar, O₃ pollution increased disease intensity, even after applying a commercially available product to enhance resistance (acibenzolar-S-methyl, BTH). In the more susceptible cultivar, level of disease attained depended on the oxidative balance that resulted from other stress factors. The antioxidant capacity of the plant at the time of infection was relevant for controlling development of the disease. Our results suggest that development of O₃ tolerance in commercial crops might impose a penalty cost in terms of disease management under projected higher O₃ concentrations.

Caffeine supplementation in diet mitigates Aeromonas hydrophila-induced impairment of the gill phosphotransfer network in grass carp Ctenopharyngodon idella

Some evidence suggests the involvement of phosphotransfer network in the pathogenesis of fish bacterial diseases, catalyzed by creatine kinase (CK), pyruvate kinase (PK) and adenylate kinase (AK); nevertheless, the effects on fish affected by Aeromonas hydrophila remain unknown. Recent evidence suggested a potent protective effect of caffeine on the branchial phosphotransfer network of fish subjected to challenge conditions. Therefore, the aim of this study was to evaluate whether A. hydrophila infection impaired branchial bioenergetics. We also determined whether dietary supplementation with caffeine protected against A. hydrophila-induced gill bioenergetic imbalance. We found that branchial cytosolic CK and AK activities were significant lower in fish experimentally infected with A. hydrophila than in uninfected fish, while mitochondrial CK activity was significant higher. Branchial lactate dehydrogenase (LDH) activity and lactate levels were significant higher in fish experimentally infected by A. hydrophila than in uninfected fish, while sodium-potassium ion pump (Na⁺, K⁺-ATPase) activity and adenosine triphosphate (ATP) levels were significant lower. No significant difference was observed between groups with respect to branchial PK activity. The dietary supplementation with 8% caffeine improved the branchial CK (cytosolic and mitochondrial), AK, and LDH activities, as well as ATP levels, but did not prevent increases in branchial lactate levels or the inhibition of Na⁺, K⁺-ATPase activity elicited by aeromonosis. Based on this evidence, we believe that reduction of CK (cytosolic) and AK activities contributes to impairment of bioenergetic homeostasis, while augmentation of mitochondrial CK activity can be considered an attempt to prevent or reduce the energetic imbalance during aeromonosis caused by A. hydrophila. The use of 8% caffeine dietary supplementation improved the energetic metabolism via protective effects on CK and AK activities, avoiding the necessity of using anaerobic metabolism. In summary, 8% dietary caffeine can be used to improve branchial energetic homeostasis during aeromonosis caused by A. hydrophila.

Involvement of the phosphoryl transfer network on cardiac energetic metabolism during Staphylococcus aureus infection and its association to disease pathophysiology

Evidences have suggested that the phosphoryl transfer network by the enzymatic activities of creatine kinase (CK), adenylate kinase (AK), pyruvate kinase (PK), and lactate dehydrogenase (LDH), shows new perspectives to understand some disturbances in the energy metabolism during bacterial infections. Thus, the aim of this study was to evaluate whether Staphylococcus aureus infection in mice could alter serum and cardiac activities of these enzymes and their association to disease pathophysiology. For that, we measured total leukocytes, lymphocytes and neutrophils (just 48 h of infection) that were lower in infected animals after 48 and 72 h in infected mice compared with negative control, while total protein and globulin plasma levels were higher after 72 h of infection. The serum CK activity was higher in infected animals 48 and 72 h post-infection compared to the control group, as well as observed for mitochondrial cardiac CK activity. The serum PK activity was higher in infected animals after 72 h of infection compared to the control group, and lower in the cardiac tissue. The cardiac AK activity was lower in infected animals 48 h and 72 h post-infection compared to the control group, while serum and cardiac LDH activities were higher. Based on these evidences, it is possible to conclude that the stimulation of CK activity exerts a key role as an attempt to maintain the bioenergetic homeostasis by the production of phosphocreatine to avoid a rapid fall on the concentrations of total adenosine triphosphate. In summary, the phosphoryl transfer network can be considered a pathway involved in the improvement on tissue and cellular energy homeostasis of S. aureus-infected mice.

Is urethral microscopy useful in symptomatic male patients without urethral discharge?

National guidelines recommend that male patients presenting with symptoms of urethritis or epididymo-orchitis undergo a urethral swab for microscopy. However, this is resource intensive. The aim of this audit was to determine the proportion of symptomatic patients without urethral discharge who have positive findings on urethral swab microscopy and explore associations between presenting symptoms and microscopy findings. We conducted a retrospective audit of symptomatic male patients who underwent microscopy. There was a significant difference between the percentage of symptomatic patients with positive findings on microscopy in those with and without urethral discharge (67% vs 33%, p < 0.001). In a patient presenting with symptoms other than urethral discharge, the likelihood that positive findings on microscopy would occur in a patient with dysuria was 4.73 times more likely than if they did not have dysuria, when controlling for age, testicular pain or discomfort, and urethral discomfort or penile irritation (p < 0.01). In situations where there are limited resources, patients without urethral discharge presenting with dysuria could be prioritised. However, further research is required to identify and stratify which patients require microscopy.

A pharmaco-epidemiological study of antibacterial treatments and bacterial diseases in Norwegian aquaculture from 2011 to 2016

The sales and prescription of antibacterials for use in Norwegian fish-farming according to diagnosis, fish species and production stage from 2011 to 2016 are analysed. The study is based on antibacterial sales data from wholesalers, pharmacies and feed mills and on prescription data obtained from a register of all prescriptions of antibacterials used in farmed fish. The results show that the fish-farming industry uses very small volumes of antibacterials. In 2016, a total of 212 kg were sold; the only antibacterial substances sold were florfenicol and oxolinic acid. The total amount corresponded to 0.16 mg kg-1 fish slaughtered, or to approximately 0.14% of the fish produced that year. The majority of prescriptions were for non-specific bacterial infections; as most common diseases are under control by vaccination. Most prescriptions for salmonid fish were during early production stages. However, due to higher biomasses of fish, the highest quantities of antibacterials were prescribed during the seawater production phase of Atlantic salmon Salmo salar. An increasing proportion of the prescriptions was for other species, including cleaner fish used for salmon lice control; in 2016 most prescriptions were for this fish category. Due to the negligible use of antibacterials in Norwegian aquaculture, in particular for on-growers, the risk of development of antimicrobial resistance and its transmission to humans through consumption of fish is considered negligible.

Higher specialty training in genitourinary medicine: A curriculum competencies-based approach

Specialty trainees in genitourinary medicine (GUM) are required to attain competencies described in the GUM higher specialty training curriculum by the end of their training, but learning opportunities available may conflict with service delivery needs. In response to poor feedback on trainee satisfaction surveys, a four-year modular training programme was developed to achieve a curriculum competencies-based approach to training. We evaluated the clinical opportunities of the new programme to determine: (1) Whether opportunity cost of training to service delivery is justifiable; (2) Which competencies are inadequately addressed by direct clinical opportunities alone and (3) Trainee satisfaction. Local faculty and trainees assessed the 'usefulness' of the new modular programme to meet each curriculum competence. The annual General Medical Council (GMC) national training survey assessed trainee satisfaction. The clinical opportunities provided by the modular training programme were sufficiently useful for attaining many competencies. Trainee satisfaction as captured by the GMC survey improved from two reds pre- to nine greens post-intervention on a background of rising clinical activity in the department. The curriculum competencies-based approach to training offers an objective way to balance training with service provision and led to an improvement in GMC survey satisfaction.

Aeromonas caviae alters the activities of ecto-enzymes that hydrolyze adenine nucleotides in fish thrombocytes

It is recognized that the purinergic system, through the activities of ectonucleoside triphosphate diphosphohydrolase (E-NTPDase), ecto-5'-nucleotidase (E-5'-nucleotidase), and ecto-adenosine deaminase (E-ADA), is involved in the regulation and modulation of the physiological and pathological events linked to hemostasis. This occurs due to the role of adenosine diphosphate (ADP) in the activation and recruitment of platelets, and the role of adenosine (Ado) in the inhibition of platelet activation. Thus, here we aimed to evaluate whether Aeromonas caviae infection impairs the ecto-enzymes of the purinergic system in fish thrombocytes and the involvement of this system in the hemorrhagic septicemia. The total number of fish thrombocytes decreased in infected animals compared to uninfected animals. Regarding the ecto-enzymes of the purinergic system, the E-NTPDase and E-5'-nucleotidase activities increased in infected animals compared to uninfected animals, while the E-ADA activity decreased. These findings show that adenine nucleotide hydrolysis is modified in the thrombocytes of fish experimentally infected with A. caviae, which impairs the coagulation process due the excessive hydrolysis of ADP, a molecule linked with activation and recruitment of thrombocytes at the site of vascular injury, and augmentation on Ado levels, a molecule linked with inhibitory effects on platelet activation and aggregation. In summary, the purinergic system might contribute to the occurrence of hemorrhagic frames in fish infected with A. caviae.

Histopathological studies of experimental Aeromonas hydrophila infection in blue tilapia, Oreochromis aureus

Blue tilapia, Oreochromis aureus, was experimentally infected with Aeromonas hydrophila, a bacterium that damages the gills, liver, and intestine, resulting in histopathological changes in the infected organs. Our histopathological study showed an aggregation of hemocytes with cell necrosis in gills; a massive aggregation of hemocytes and pyknotic nuclei in the hepatopancreas; and a lower rate of hemocyte aggregation in the digestive system of the infected fish.

Bacterial arthropod-borne diseases in West Africa

Arthropods such as ticks, lice, fleas and mites are excellent vectors for many pathogenic agents including bacteria, protozoa and viruses to animals. Moreover, many of these pathogens can also be accidentally transmitted to humans throughout the world. Bacterial vector-borne diseases seem to be numerous and very important in human pathology, however, they are often ignored and are not well known. Yet they are in a phase of geographic expansion and play an important role in the etiology of febrile episodes in regions of Africa. Since the introduction of molecular techniques, the presence of these pathogens has been confirmed in various samples from arthropods and animals, and more rarely from human samples in West Africa. In this review, the aim is to summarize the latest information about vector-borne bacteria, focusing on West Africa from 2000 until today in order to better understand the epidemiological risks associated with these arthropods. This will allow health and veterinary authorities to develop a strategy for surveillance of arthropods and bacterial disease in order to protect people and animals.

Anetoderma due to secondary syphilis: Report of two cases and discussion of the histopathological findings

Anetoderma is a rare benign condition of diverse etiology whose characteristic is the diminution or absence of the dermal elastic fibers. Classified as primary and secondary, the latter associated with tumors, inflammatory, and infectious diseases. Although the etiology of the lesions is well described in literature, the pathogenesis is still poorly determined. Anetoderma in syphilis is rare, and occurs even in the most uncommon cutaneous manifestations of the disease, such as the nodular form. In order to better understand the changes that lead to elastolysis, we propose a better correlation with the histopathological findings of the lesions that precede it. We present two cases of anetoderma secondary to syphilis, whose clinical aspects resembled the pattern of their initial secondary syphilis rash.

Mortality in patients with HIV-1 and tuberculosis co-infection in Rio de Janeiro, Brazil - associated factors and causes of death

BACKGROUND

Tuberculosis is the most frequent opportunistic infection and the leading cause of death among persons living with HIV in several low and middle-income countries. Mortality rates during tuberculosis treatment and death causes among HIV-1/TB co-infected patients may differ based on the immunosuppression severity, timing of diagnosis and prompt initiation of tuberculosis and antiretroviral therapy.

METHODS

This was a retrospective observational study conducted in the clinical cohort of patients with HIV-1/Aids of the National Institute of Infectious Diseases Evandro Chagas, Rio de Janeiro, Brazil. All HIV-1 infected patients who started combination antiretroviral therapy up to 30 days before or within 180 days after the start of tuberculosis treatment from 2000 to 2010 were eligible. Causes of death were categorized according to the "Coding Causes of Death in HIV" (CoDe) protocol. The Cox model was used to estimate the hazard ratio (HR) of selected mortality variables.

RESULTS

A total of 310 patients were included. Sixty-four patients died during the study period. Mortality rate following tuberculosis treatment initiation was 44 per 100 person-years within the first 30 days, 28.1 per 100 person-years within 31 and 90 days, 6 per 100 person-years within 91 and 365 days and 1.6 per 100 person-years after 365 days. Death probability within one year from tuberculosis treatment initiation was approximately 13%. In the adjusted analysis the associated factors with mortality were: CD4 ≤ 50 cells/mm3 (HR: 3.10; 95% CI: 1.720 to 5.580; p = 0.00); mechanical ventilation (HR: 2.81; 95% CI: 1.170 to 6.760; p = 0.02); and disseminated tuberculosis (HR: 3.70; 95% CI: 1.290 to 10.590, p = 0.01). Invasive bacterial disease was the main immediate cause of death (46.9%).

CONCLUSION

Our results evidence the high morbidity and mortality among patients co-infected with HIV-1 and tuberculosis in Rio de Janeiro, Brazil. During the first year following tuberculosis diagnosis, mortality was the highest within the first 3 months, being invasive bacterial infection the major cause of death. In order to successfully intervene in this scenario, it is utterly necessary to address the social determinants of health contributing to the inequitable health care access faced by this population.

Reassessment of the taxonomic position of Burkholderia andropogonis and description of Robbsia andropogonis gen. nov., comb. nov

The phylogenetic classification of the species Burkholderia andropogonis within the Burkholderia genus was reassessed using 16S rRNA gene phylogenetic analysis and multilocus sequence analysis (MLSA). Both phylogenetic trees revealed two main groups, named A and B, strongly supported by high bootstrap values (100%). Group A encompassed all of the Burkholderia species complex, whi.le Group B only comprised B. andropogonis species, with low percentage similarities with other species of the genus, from 92 to 95% for 16S rRNA gene sequences and 83% for conserved gene sequences. Average nucleotide identity (ANI), tetranucleotide signature frequency, and percentage of conserved proteins POCP analyses were also carried out, and in the three analyses B. andropogonis showed lower values when compared to the other Burkholderia species complex, near 71% for ANI, from 0.484 to 0.724 for tetranucleotide signature frequency, and around 50% for POCP, reinforcing the distance observed in the phylogenetic analyses. Our findings provide an important insight into the taxonomy of B. andropogonis. It is clear from the results that this bacterial species exhibits genotypic differences and represents a new genus described herein as Robbsia andropogonis gen. nov., comb. nov.

Stroke in a young patient with neurosyphilis and HIV

Syphilis has long been known as the great imitator. Its heterogeneity can manifest in the form of meningitis, space occupying gummas, vasculitis, strokes, cranial neuropathies, myelopathy, dementia, and seizures. The incidence has been rising with each year, mainly in men who have sex with men accounting for 83% of cases. With the coexistence of immunocompromised states, especially HIV (human immunodeficiency virus), the usually chronic and insidious course of tertiary neurosyphilis can be accelerated. Stroke can occur as a result of neurosyphilis in its meningovascular form, and the likelihood of this increases with HIV co-infection, especially in high-risk groups such as intravenous drug users and men who have sex with men. Here, we discuss a case of a young man who presented with an ischemic stroke found to have neurosyphilis and HIV and consider the management of these co-morbid conditions.

R-gene variation across Arabidopsis lyrata subspecies: effects of population structure, selection and mating system

Background

Examining allelic variation of R-genes in closely related perennial species of Arabidopsis thaliana is critical to understanding how population structure and ecology interact with selection to shape the evolution of innate immunity in plants. We finely sampled natural populations of Arabidopsis lyrata from the Great Lakes region of North America (A. l. lyrata) and broadly sampled six European countries (A. l. petraea) to investigate allelic variation of two R-genes (RPM1 and WRR4) and neutral genetic markers (Restriction Associated DNA sequences and microsatellites) in relation to mating system, phylogeographic structure and subspecies divergence.

Results

Fine-scale sampling of populations revealed strong effects of mating system and population structure on patterns of polymorphism for both neutral loci and R-genes, with no strong evidence for selection. Broad geographic sampling revealed evidence of balancing selection maintaining polymorphism in R-genes, with elevated heterozygosity and diversity compared to neutral expectations and sharing of alleles among diverged subspecies. Codon-based tests detected both positive and purifying selection for both R-genes, as commonly found for animal immune genes.

Conclusions

Our results highlight that combining fine and broad-scale sampling strategies can reveal the multiple factors influencing polymorphism and divergence at potentially adaptive genes such as R-genes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12862-016-0665-5) contains supplementary material, which is available to authorized users.

Sexually transmitted infection diagnoses among Hispanic immigrant and migrant men who have sex with men in the United States

Hispanic immigrant/migrant men who have sex with men (MSM) should be at higher risk for sexually transmitted infections/human immunodeficiency virus (STIs/HIV) given individual-level factors associated with the migration process that have been theorised to increase susceptibility to STIs/HIV among migrant populations. However, relatively little is known if these individual level factors are actually associated with the STI prevalence among this population. During 2005-2007, 2576 men and women foreign-born Hispanics were surveyed at three community-based organisations offering services to immigrant/migrant communities in the US. We analysed demographic characteristics, sexual risk behaviours, migration patterns, and factors associated with STI diagnoses (syphilis, chlamydia, and gonorrhoea) in the past 12 months among Hispanic immigrant/migrant MSM. Of 1482 Hispanic immigrant/migrant men surveyed who reported having sex in the past 12 months, 353 (24%) reported sex with a man, and of these, 302 answered questions regarding whether or not they had been diagnosed with a bacterial STI in the past year. Of these 302 men, 25% reported being married; 42% self-identified as being heterosexual and 20% as bisexual. Twenty-nine (9.6%) men reported that they had received an STI diagnosis in the past year. In the multivariate logistic regression model, men who reported receiving money or goods for sex had increased odds of a self-reported STI diagnosis. The prevalence of bacterial STIs among Hispanic immigrant/migrant MSM is lower than the prevalence of bacterial STIs among other MSM in the United States. Nevertheless, receiving money or goods for sex was significantly associated with a self-reported STI diagnosis among Hispanic immigrant/migrant MSM. It is important to understand factors contributing to participation in exchange sex among this population. HIV/STI prevention interventions tailored to non-gay identifying MSM are important for Hispanic immigrant/migrant MSM.