Vibrio vulnificus infection: a persistent threat to public health

A systematic review of the avian antibody (IgY) therapeutic effects on human bacterial infections over the decade

The overuse of antibiotics worldwide, especially during the Coronavirus pandemic, has raised concerns about the rise of antibiotic resistance and its side effects. Immunoglobulin Y, a natural protein that specifically targets foreign antigens, holds promise as a potential therapeutic option, particularly for individuals with sensitive immune systems. Despite numerous studies on IgY, the optimal administration method, effective dose, target antigen, and potential side effects of this antibody remain areas of active research and challenge. This review selected and evaluated articles published in the last ten years from databases such as PubMed and Science Direct with appropriate keywords discussing the therapeutic effects of immunoglobulin Y in human infections in vivo. Out of all the reviewed articles, 35 articles met the inclusion criteria. The results showed that the specific antibody against dental, respiratory, and skin infections has an acceptable effectiveness. In contrast, some infections, such as neurological infections, including tetanus and botulism, still need further investigation due to the short survival time of mice. On the other hand, reporting side effects such as antibody-dependent enhancement in some infections limits its use.

Early diagnosis and application of hemopurification combined with antibiotic therapy and surgical debridement for successful treatment of a child with Vibrio vulnificus necrotizing fasciitis and septic shock: a case report

BACKGROUND

Vibrio vulnificus (V. vulnificus) is a halophilic marine Gram-negative bacterium. Necrotizing fasciitis caused by V. vulnificus is a rapidly progressing clinical emergency often accompanied by septic shock. Despite advances in antibiotics and infection control measures, it remains a highly fatal and disabling infection. The incidence of V. vulnificus infection has increased due to climate warming and expanded global seafood trade in recent years. However, pediatric cases of V. vulnificus infection remain rare, leading to limited clinical experience in their management.

METHODS

This report analyzes the clinical data of a pediatric case of V. vulnificus necrotizing fasciitis with septic shock, treated at Zhuhai Center for Maternal and Child Health Care in April 2024. The report also reviews the literature on pediatric V. vulnificus infection.

RESULTS

A 26-month-old boy developed a V. vulnificus infection after being scratched by a sea bass. The patient experienced an acute onset of illness that quickly worsened, presenting with a fever, mental fatigue, soft tissue edema, and pain, necrosis of the fascia and foot, coagulation dysfunction, and even shock. Laboratory results revealed white blood cell count(5.0 × 109/L), neutrophilia %(65%), thrombocytopenia (56 × 109/L), elevated CRP (200 mg/L), PCT (67.4 ng/mL), and IL-6 (> 4000 pg/mL), hypoalbuminemia (17.4 g/L), prolonged PT (17.5 s), reduced total T and NK cell counts, and a significantly reduced proportion of Treg cells. Initial treatment included surgical debridement and drainage, empirical antibiotic therapy, and rapid diagnosis of V. vulnificus via bacterial wound culture. Next-generation sequencing (NGS) of the blood microbial macrogenome and high-throughput sequencing of wound microbial pathogens (MetCap) were performed. Antibiotics were selected based on drug sensitivity testing, accompanied by hemopurification and measures to prevent disseminated intravascular coagulation. The patient's condition stabilized gradually post-treatment, and he was discharged.

CONCLUSION

Prompt diagnosis is important for children with seafood exposure. Early hemopurification, surgical intervention, effective antibiotic therapy, and DIC prevention significantly improve prognosis and survival rates. These findings provide a practical reference for managing pediatric V. vulnificus infections.

Genome-wide phenotypic profiling of transcription factors and identification of novel targets to control the virulence of Vibrio vulnificus

For successful infection, the life-threatening pathogen Vibrio vulnificus elaborately regulates the expression of survival and virulence genes using various transcription factors (TFs). In this study, a library of the V. vulnificus mutants carrying specific signature tags in 285 TF genes was constructed and subjected to 16 phenotypic analyses. Consequently, 89 TFs affecting more than one phenotype of V. vulnificus were identified. Of these, 59 TFs affected the in vitro survival including growth, stress resistance, biofilm formation and motility, and 64 TFs affected the virulence of V. vulnificus. Particularly, 27 of the 64 TFs enhanced the in vitro hemolytic or cytotoxic activities, and 8 of the 27 TFs also increased the in vivo brine shrimp or murine infectivities of V. vulnificus. Among the eight TFs, HlyU, IscR, NagC, MetJ and Tet2 did not affect the growth of V. vulnificus but still regulated the expression of major exotoxin genes, including rtxA, vvhA and plpA, thereby emerging as potential drug targets for anti-virulence therapies with low selective pressure for developing resistance. Altogether, this study characterized the functions of TFs at a genome-wide scale and identified novel targets to control the virulence of V. vulnificus.

The role of MNK1-mTORC1 pathway in modulating macrophage responses to Vibrio vulnificus infection

Vibrio vulnificus (Vv) is known to cause life-threatening infections, particularly septicemia. These patients often exhibit elevated levels of pro-inflammatory cytokines. While it is established that mitogen-activated protein kinase (MAPK)-interacting kinase (MNK) contributes to the production of pro-inflammatory cytokines, the role of MNK in macrophages during Vv infection remains unclear. In this study, we investigate the impact of MNK on macrophages. We demonstrate that the inhibition of MNK in J774A.1 cells, when treated with lipopolysaccharide or Vv, resulted in decreased production of tumor necrosis factor alpha and interleukin-6, without affecting their transcription. Interestingly, treatment with MNK inhibitor CGP57380 led to enhanced phosphorylation of MNK1 but decreased phosphorylation of eIF4E. Moreover, MNK1 knockout cells exhibited an increased capacity for phagocytosis and clearance of Vv, with more acidic phagosomes than the parental cells. Notably, CGP57380 did not impact phagocytosis, bacterial clearance, or phagosome acidification in Vv-infected J774A.1 cells. Considering the reported association between MNK and mammalian target of rapamycin complex 1 (mTORC1) activation, we investigated the mTORC1 signaling in MNK1 knockout cells infected with Vv. Our results revealed that attenuation of the mTORC1 signaling in these cells and treatment with the mTORC1 inhibitor rapamycin significantly enhanced bacterial clearance in J774A.1 cells following Vv infection. In summary, our findings suggest that MNK promotes the Vv-induced cytokine production in J774A.1 cells without affecting their transcription levels. MNK1 appears to impair the phagocytosis, bacterial clearance, and phagosome acidification in Vv-infected J774A.1 cells through the MNK1-mTORC1 signaling pathway rather than the MNK1-eIF4E signaling pathway. Our findings highlight the importance of the MNK1-mTORC1 pathway in modulating macrophage responses to Vv infection.

IMPORTANCE

Mitogen-activated protein kinase (MAPK)-interacting kinase (MNK) plays a role in promoting the production of tumor necrosis factor alpha and interleukin-6 in macrophages during Vibrio vulnificus (Vv) infection. Inhibition or knockout of MNK1 in J774A.1 cells resulted in reduced cytokine production without affecting their transcription levels. MNK1 also impairs phagocytosis, bacterial clearance, and phagosome acidification in Vv-infected cells through the MNK1-mammalian target of rapamycin complex 1 (mTORC1) signaling pathway. The findings highlight the importance of the MNK1-mTORC1 pathway in modulating macrophage responses to Vv infection.

Non-cholera Vibrio spp. invasive infections in the summer following May 2023 flood disaster in Romagna, Italy: a case series

Non-cholera Vibrio spp. includes ubiquitous organisms living in aquatic environments. Their occurrence is associated with global warming and meteorological disasters. In May 2023 the Romagna region, Italy, was affected by severe floods. In the following 15 weeks we observed 5 patients with invasive infections caused by V. vulnificus (3/5) and V. harveyi (2/5). All patients (median age 77 years) had medical comorbidities and shared exposure to seawater. Two patients needed surgery; 2 died. In conclusion, we observed an increased burden of Vibrio spp. invasive infections after May 2023 floods, affecting old patients with predisposing medical conditions.

Haemolysins are essential to the pathogenicity of deep-sea Vibrio fluvialis

Vibrio fluvialis is an emerging foodborne pathogen that produces VFH (Vibrio fluvialis hemolysin) and δVFH (delta-Vibrio fluvialis hemolysin). The function of δVFH is unclear. Currently, no pathogenic V. fluvialis from deep sea has been reported. In this work, a deep-sea V. fluvialis isolate (V13) was examined for pathogenicity. V13 was most closely related to V. fluvialis ATCC 33809, a human isolate, but possessed 262 unique genes. V13 caused lethal infection in fish and induced pyroptosis involving activation of the NLRP3 inflammasome, caspase 1 (Casp1), and gasdermin D (GSDMD). V13 defective in VFH or VFH plus δVFH exhibited significantly weakened cytotoxicity. Recombinant δVFH induced NLRP3-Casp1-GSDMD-mediated pyroptosis in a manner that depended on K+ efflux and intracellular Ca2+ accumulation. δVFH bound several plasma membrane lipids, and these bindings were crucial for δVFH cytotoxicity. Together these results provided new insights into the function of δVFH and the virulence mechanism of V. fluvialis.

Vibrio vulnificus infection from tilapia sting wounds in an inland city: A case report

Vibrio vulnificus is a pathogen that can cause serious and fatal infections, primarily associated with a history of contact with the sea or aquatic organisms or products. However, with global climate change and increased global seafood trade, V. vulnificus infections are also occurring in non-coastal areas. In this report, we present the successful diagnosis and treatment of a case of necrotizing wound caused by V. vulnificus infection in an inland city in southwest China. In addition, we review the epidemiology and distribution of V. vulnificus in China and related vaccine research, which may provide a reference for the clinical diagnosis and treatment of V. vulnificus infection.

Increased incidence of vibriosis in Maryland, U.S.A., 2006-2019

BACKGROUND

Vibrio spp. naturally occur in warm water with moderate salinity. Infections with non-cholera Vibrio (vibriosis) cause an estimated 80,000 illnesses and 100 fatalities each year in the United States. Climate associated changes to environmental parameters in aquatic ecosystems are largely promoting Vibrio growth, and increased incidence of vibriosis is being reported globally. However, vibriosis trends in the northeastern U.S. (e.g., Maryland) have not been evaluated since 2008.

METHODS

Vibriosis case data for Maryland (2006-2019; n = 611) were obtained from the COVIS database. Incidence rates were calculated using U.S. Census Bureau population estimates for Maryland. A logistic regression model, including region, age group, race, gender, occupation, and exposure type, was used to estimate the likelihood of hospitalization.

RESULTS

Comparing the 2006-2012 and 2013-2019 periods, there was a 39% (p = 0.01) increase in the average annual incidence rate (per 100,000 population) of vibriosis, with V. vulnificus infections seeing the greatest percentage increase (53%, p = 0.01), followed by V. parahaemolyticus (47%, p = 0.05). The number of hospitalizations increased by 58% (p = 0.01). Since 2010, there were more reported vibriosis cases with a hospital duration ≥10 days. Patients from the upper eastern shore region and those over the age of 65 were more likely (OR = 6.8 and 12.2) to be hospitalized compared to other patients.

CONCLUSIONS

Long-term increases in Vibrio infections, notably V. vulnificus wound infections, are occurring in Maryland. This trend, along with increased rates in hospitalizations and average hospital durations, underscore the need to improve public awareness, water monitoring, post-harvest seafood interventions, and environmental forecasting ability.

Case Report: First case of HIV, hepatitis B, hepatitis C, and Vibrio vulnificus coinfection

Our patient, a 48-year-old man from Guangdong's coastal region, worked selling and processing oysters and other seafood. He started experiencing swelling and pain in his left knee on October 4, 2022, and they got worse over time. The findings of mNGS test showed Vibrio vulnificus infection. The patient had AIDS, hepatitis A and hepatitis B concurrently. He was admitted to the hospital's intensive care unit (ICU) for treatment as his symptoms worsened. We refrained from performing an amputation because the family members expressed a desire to keep the limb. The limb was managed with regular dressing changes, thorough debridement, wound closure, ongoing VSD drainage, and local antibiotic irrigation. The patient's organ function eventually returned to normal, and the systemic infection got better. On November 1, the wound's new granulation tissue had grown well and had gradually crept to cover 80% of the wound. The tissue's blood flow had also improved, indicating a trend of growth and healing.

Integration of a CRISPR Cas12a-assisted multicolor biosensor and a micropipette tip enables visible point-of-care testing of foodborne Vibrio vulnificus

Foodborne pathogens cause numerous food safety problems, and as a virulent bacterium falling under this category, Vibrio vulnificus (V. vulnificus) poses a huge threat to public health. The conventional methods used for the detection of V. vulnificus, including culture-based and molecular detection methods, have a variety of drawbacks, including being time-consuming and labor-intensive, the requirement of large-scale equipment, and the lack of professional operators. This paper establishes a visible detection platform for V. vulnificus based on CRISPR/Cas12a, which is integrated with nucleic acid isothermal amplification and β-galactosidase-catalyzed visible color reaction. The specific vvhA gene and a conservative segment in the 16S rDNA gene of the Vibrio genus were selected as the detection targets. By using spectrum analysis, this CRISPR detection platform achieved sensitive detection of V. vulnificus (1 CFU per reaction) with high specificity. Through the color transformation system, as low as 1 CFU per reaction of V. vulnificus in both bacterial solution and artificially contaminated seafood could be visibly observed with the naked eye. Furthermore, the consistency between our assay and the qPCR assay in the detection of V. vulnificus spiked seafood was confirmed. In general, this visible detection platform is user-friendly, accurate, portable, and equipment-free, and is expected to provide a powerful supplement in point-of-care testing of V. vulnificus and also holds good promise for future application in foodborne pathogen detection.

Genomic characterization and identification of virulence-related genes in Vibrio nigripulchritudo isolated from white leg shrimp Penaeus vannamei

Vibrio nigripulchritudo causes vibriosis in penaeid shrimps. Here, we used Illumina and Nanopore sequencing technologies to sequence the genomes of three of its strains (TUMSAT-V. nig1, TUMSAT-V. nig2, and TUMSAT-V. nig3) to explore opportunities for disease management. Putative virulence factors and mobile genetic elements were detected while evaluating the phylogenetic relationship of each isolated strain. The genomes consisted of two circular chromosomes (I and II) plus one or two plasmids. The size of chromosome I ranged from 4.02 to 4.07 Mb with an average GC content of 46%, while the number of predicted CDSs ranged from 3563 to 3644. The size of chromosome II ranged from 2.16 to 2.18 Mb, with an average GC content of 45.5%, and the number of predicted CDSs ranged from 1970 to 1987. Numerous virulence genes were identified related to adherence, antiphagocytosis, chemotaxis, motility, iron uptake, quorum sensing, secretion systems, and toxins in all three genomes. Higher numbers of prophages and genomic islands found in TUMSAT-V. nig1 suggest that the strain has experienced numerous horizontal gene transfer events. The presence of antimicrobial resistance genes suggests that the strains have multidrug resistance. Comparative genomic analysis showed that all three strains belonged to the same clade.

Distribution, Prevalence, and Antibiotic Susceptibility Profiles of Infectious Noncholera Vibrio Species in Malaysia

Background

The noncholera Vibrio spp. which cause vibriosis are abundantly found in our water ecosystem. These bacteria could negatively affect both humans and animals. To date, there is a paucity of information available on the existence and pathogenicity of this particular noncholera Vibrio spp. in Malaysia in comparison to their counterpart, Vibrio cholera.

Methods

In this study, we extracted retrospective data from Malaysian surveillance database. Analysis was carried out using WHONET software focusing noncholera Vibrio spp. including Vibrio parahaemolyticus, Vibrio vulnificus, Vibrio fluvialis, Vibrio alginolyticus, Vibrio hollisae (Grimontia hollisae), Vibrio mimicus, Vibrio metschnikovii, and Vibrio furnissii.

Results

Here, we report the first distribution and prevalence of these species isolated in Malaysia together with the antibiotic sensitivity profile based on the species. We found that V. parahaemolyticus is the predominant species isolated in Malaysia. Noticeably, across the study period, V. fluvialis is becoming more prevalent, as compared to V. parahaemolyticus. In addition, this study also reports the first isolation of pathogenic V. furnissii from stool in Malaysia.

Conclusion

These data represent an important step toward understanding the potential emergence of noncholera Vibrio spp. outbreaks.

Vibrio vulnificus pneumonia with multiorgan failure: a case report and review of the literature

BACKGROUND

Vibrio vulnificus is a gram-negative bacterium causing three clinical syndromes namely, gastrointestinal symptoms, skin sepsis and primary sepsis. Primary sepsis exhibits mortality rates exceeding 50%, particularly in the immunocompromised. Vibrio vulnificus is transmitted via consumption of contaminated seafood and contaminated seawater skin exposure. We describe a rare case of an immunocompetent male presenting with an atypical Vibrio vulnificus infection, culminating in severe pneumonia requiring intensive care.

CASE PRESENTATION

A 46 year old Indian male dockyard worker, a non-smoker and teetotaler, of Indian origin presented to the emergency treatment unit of a tertiary care hospital in Sri Lanka, with fever, productive cough with yellow sputum, pleuritic chest pain and tachypnea for five days. He had no gastrointestinal or skin manifestations. His respiratory rate was 38 breaths/min, pulse rate was 120 bpm, blood pressure was 107/75 mmHg and pulse oximetry was 85% on air. Chest X-ray revealed consolidation of the left lung. Empiric intravenous Piperacillin-tazobactam and Clarithromycin were commenced after obtaining blood and sputum cultures. Over the next 24 h, his oxygen requirement rose and as he required vasopressor support, he was admitted to the intensive care unit. He was intubated and bronchoscopy was performed on day two, which demonstrated thick secretions from left upper bronchial segments. His antibiotics were changed to intravenous ceftriaxone and doxycycline following a positive blood culture report of Vibrio vulnificus. He was ventilated for ten days and his intensive care stay was complicated with a non-oliguric acute kidney injury, with serum creatinine rising up to 8.67 mg/dL (0.81-0.44 mg/dL). He developed mild thrombocytopenia with platelets dropping to 115 × 10³ /uL (150-450 × 10³/uL) which resolved spontaneously. Vasopressors were weaned off by day eight and the patient was extubated on day ten. He was discharged from intensive care on day twelve and made a full recovery.

CONCLUSIONS

Pneumonia itself is an atypical manifestation of Vibrio vulnificus and furthermore, this patient was immunocompetent and did not exhibit the classical gastro-intestinal and skin manifestations. This case highlights the occurrence of atypical Vibrio sp. infections in patients with high exposure risks and the need for early supportive and appropriate antibiotic therapies.

Detection of V. vulnificus septic shock with ARDS using mNGS

The latest surveillance from the Centers for Disease Control and Prevention shows that the annual incidence of V. vulnificus infection is increasing. Unfortunately, in less well-known high-risk groups, this infection is usually excluded from differential diagnosis. Transmitted through wound exposure or ingestion, the mortality rate of foodborne diseases of V. vulnificus is the highest of all V. vulnificus. V. vulnificus is as lethal early diagnosis as Ebola and bubonic plague, so timely treatment is imperative. Sepsis caused by V. vulnificus infection mainly exists in the United States and is rarely reported in Southeast Asia. We report a 78-year-old man who went to the local hospital and complained of swelling in his right hand with severe pain. He ate raw salmon 2 days ago and denied other recognized seafood stab or trauma history and other seafood contact history. He was in septic shock at the time of treatment, so we immediately transferred to the emergency intensive care unit and tested for metagenomic next-generation sequencing (mNGS). The diagnosis was confirmed the second day after admission, and eventually he was cured and discharged from the hospital only after medical treatment, thus avoiding the risk of surgical debridement or even amputation. mNGS is helpful for early clinical diagnosis and effective early intervention for etiology, so that patients can get a good prognosis.

Pathogenic mechanism of Vibrio vulnificus infection

Vibrio vulnificus is a fatal, opportunistic human pathogen transmitted through the consumption of raw/undercooked seafood or direct contact. V. vulnificus infection progresses rapidly and has severe consequences; some cases may require amputation or result in death. Growing evidence suggests that V. vulnificus virulence factors and regulators play a large role in disease progression, involving host resistance, cellular damage, iron acquisition, virulence regulation and host immune responses. Its disease mechanism remains largely undefined. Further evaluation of pathogenic mechanisms is important for selecting appropriate measures to prevent and treat V. vulnificus infection. In this review, the possible pathogenesis of V. vulnificus infection is described to provide a reference for treatment and prevention.

Strategic modification of low-activity natural antimicrobial peptides confers antibacterial potential in vitro and in vivo

Antimicrobial peptides (AMPs) show great promise for clinical applications, but the utility of naturally occurring AMPs is often limited by their stability. Here, we used a rational design approach to improve the characteristics of a pair of inactive peptides, tilapia piscidin 1 and 2 (TP1 and TP2). From each starting peptide, we generated a series of novel derivatives by substituting residues to adjust cationic charge density, percent hydrophobicity and hydrophilicity/hydrophobicity coefficients. This approach yielded a novel peptide, TP2-5 (KKCIAKAILKKAKKLLKKLVNP), that exhibits significant bactericidal potency, low cytotoxicity and high stability. The designed peptide further showed antibiofilm activity, rapid antibacterial action and a low capacity to induce bacterial resistance. Importantly, we also demonstrated that TP2-5 can protect mice in a Vibrio vulnificus-infected wound model. Therefore, our peptide modification strategy successfully generated a novel AMP with high potential for future clinical application.

Vibrio vulnificus-Induced Necrotizing Fasciitis Complicated by Multidrug-Resistant Acinetobacter baumannii Infection: Efficacy of Chemical Necrectomy Using 40% Benzoic Acid

Necrotizing fasciitis is a life-threatening skin and soft tissue infection associated with high morbidity and mortality in adult patients. This infection can present as either type 1 infection caused by a mixed microflora (Streptococci, Enterobacteriacae, Bacteroides sp., and Peptostreptococcus sp.), most commonly developing in patients after surgery or in diabetic patients, or as type 2. The latter type is monomicrobial and, usually, caused by group A Streptococci. Rarely, this type can be also caused by other pathogens, such as Vibrio vulnificus. V vulnificus is a small mobile Gram-negative rod capable of causing 3 types of infections in humans-gastroenteritis, primary infection of the vascular bed, and wound infections. If infecting a wound, V vulnificus can cause a life-threatening condition-necrotizing fasciitis. We present a rare case of necrotizing fasciitis developing after an insect bite followed by exposure to the seawater. Rapid propagation of the infectious complication in the region of the right lower limb led to a serious consideration of the necessity of amputation. Due to the clearly demarcated necroses and secondary skin and soft tissue infection caused by a multiresistant strain of Acinetobacter baumannii, we, however, resorted to the use of selective chemical necrectomy using 40% benzoic acid-a unique application in this kind of condition. The chemical necrectomy was successful, relatively gentle and thanks to its selectivity, vital parts of the limb remained preserved and could have been subsequently salvaged at minimum blood loss. Moreover, the antimicrobial effect of benzoic acid led to rapid decolonization of the necrosis and wound bed preparation, which allowed us to perform defect closure using split-thickness skin grafts. The patient subsequently healed without further complications and returned to normal life.

Analysis of clinical characteristics, pathogen infection, and drug sensitivity of Marine injury patients: A cross-sectional study

The infection rate is high in patients injured at sea, and because of the unique distribution of marine microorganisms, the infection is often not easily controlled effectively with the empirical application of antibiotics. This study aims to consider the clinical characteristics and pathogen infection and drug susceptibility of patients injured at sea. From 2019 to 2021, there were 635 patients injured at sea in Rizhao People's Hospital. We assess the patient's basic condition, while performing bacterial culture and drug susceptibility testing on wound exudate or pus from infected patients. Among the 635 patients injured at sea, 195 people were infected, and the infection rate was 30.71%. Infected patients are usually older, have longer prehospital visits, and have lower normal levels of red blood cells, hemoglobin, total protein, and albumin. The causes of injury in infected patients were mainly avulsion and puncture injuries, and the types of injuries were mainly bone fracture, vascular injury, and nerve injury. A total of 305 strains of pathogenic bacteria were cultured in 195 patients. Gram-negative bacteria accounted for 77.05% (235 strains), of which Proteus was the most. Gram-positive bacteria accounted for 22.95% (70 strains), of which Staphylococcus aureus was the most. Gram-negative bacilli were sensitive to aminoglycosides, lactam antibiotics, carbapenems antibiotics, sulfonamides, quinolones, fourth-generation cephalosporins, and antibacterial drugs containing enzyme inhibitors, while most of the bacteria were resistant to penicillins, first-generation cephalosporins, and second-generation cephalosporins. Gram-positive bacteria were sensitive to quinuptin/dafoptin, rifampicin, linezolid, gentamicin, tigacycline, and vancomycin but resistant to penicillin antibiotics. Due to the particularity of marine injuries, patients are prone to infection. Pathogen culture and drug sensitivity analysis play an important role in guiding antiinfective treatment for marine injured patients.

An Assay Combining Droplet Digital PCR With Propidium Monoazide Treatment for the Accurate Detection of Live Cells of Vibrio vulnificus in Plasma Samples

Vibrio vulnificus (V. vulnificus) is one of the most common pathogenic Vibrio species to humans; therefore, the establishment of timely and credible detection methods has become an urgent requirement for V. vulnificus illness surveillance. In this study, an assay combining droplet digital PCR (ddPCR) with propidium monoazide (PMA) treatment was developed for detecting V. vulnificus. The primers/probes targeting the V. vulnificus hemolysin A (vvhA) gene, amplification procedures, and PMA processing conditions involved in the assay were optimized. Then, we analyzed the specificity, sensitivity, and ability to detect live cell DNA while testing the performance of PMA-ddPCR in clinical samples. The optimal concentrations of primers and probes were 1.0 and 0.3 μM, respectively. The annealing temperature achieving the highest accuracy in ddPCR assay was 60°C. With an initial V. vulnificus cell concentration of 10⁸ CFU/mL (colony-forming units per milliliter), the optimal strategy to distinguish live cells from dead cells was to treat samples with 100 μM PMA for 15 min in the dark and expose them to LED light with an output wavelength of 465 nm for 10 min. The specificity of the PMA-ddPCR assay was tested on 27 strains, including seven V. vulnificus strains and 20 other bacterial strains. Only the seven V. vulnificus strains were observed with positive signals in specificity analysis. Comparative experiments on the detection ability of PMA-ddPCR and PMA-qPCR in pure cultures and plasma samples were performed. The limit of detection (LOD) and the limit of quantitation (LOQ) in pure culture solutions of V. vulnificus were 29.33 and 53.64 CFU/mL in PMA-ddPCR, respectively. For artificially clinical sample tests in PMA-ddPCR, V. vulnificus could be detected at concentrations as low as 65.20 CFU/mL. The sensitivity of the PMA-ddPCR assay was 15- to 40-fold more sensitive than the PMA-qPCR in this study. The PMA-ddPCR assay we developed provides a new insight to accurately detect live cells of V. vulnificus in clinical samples, which is of great significance to enhance public health safety and security capability and improve the emergency response level for V. vulnificus infection.

Antimicrobial Blue Light for Prevention and Treatment of Highly Invasive Vibrio vulnificus Burn Infection in Mice

Vibrio vulnificus is an invasive marine bacterium that causes a variety of serious infectious diseases. With the increasing multidrug-resistant variants, treatment of V. vulnificus infections is becoming more difficult. In this study, we explored antimicrobial blue light (aBL; 405 nm wavelength) for the treatment of V. vulnificus infections. We first assessed the efficacy of aBL against five strains of V. vulnificus in vitro. Next, we identified and quantified intracellular porphyrins in V. vulnificus to provide mechanistic insights. Additionally, we measured intracellular reactive oxygen species (ROS) production and bacterial membrane permeabilization following aBL exposures. Lastly, we conducted a preclinical study to investigate the efficacy and safety of aBL for the prevention and treatment of burn infections caused by V. vulnificus in mice. We found that aBL effectively killed V. vulnificus in vitro in both planktonic and biofilm states, with up to a 5.17- and 4.57-log₁₀ CFU reduction being achieved, respectively, following an aBL exposure of 216 J/cm². Protoporphyrin IX and coproporphyrins were predominant in all the strains. Additionally, intracellular ROS was significantly increased following aBL exposures (P < 0.01), and there was evidence of aBL-induced permeabilization of the bacterial membrane (P < 0.0001). In the preclinical studies, we found that female mice treated with aBL 30 min after bacterial inoculation showed a survival rate of 81% following 7 days of observation, while only 28% survival was observed in untreated female mice (P < 0.001). At 6 h post-inoculation, an 86% survival was achieved in aBL-treated female mice (P = 0.0002). For male mice, 86 and 63% survival rates were achieved when aBL treatment was given 30 min and 6 h after bacterial inoculation, respectively, compared to 32% survival in the untreated mice (P = 0.0004 and P = 0.04). aBL did not reduce cellular proliferation or induce apoptosis. We found five cytokines were significantly upregulated in the males after aBL treatment, including MCSF (P < 0.001), MCP-5 (P < 0.01), TNF RII (P < 0.01), CXCL1 (P < 0.01), and TIMP-1 (P < 0.05), and one in the females (TIMP-1; P < 0.05), suggesting that aBL may induce certain inflammatory processes. In conclusion, aBL may potentially be applied to prevent and treat V. vulnificus infections.

Vibriosis Outbreaks in Aquaculture: Addressing Environmental and Public Health Concerns and Preventive Therapies Using Gilthead Seabream Farming as a Model System

Bacterial and viral diseases in aquaculture result in severe production and economic losses. Among pathogenic bacteria, species belonging to the Vibrio genus are one of the most common and widespread disease-causing agents. Vibrio infections play a leading role in constraining the sustainable growth of the aquaculture sector worldwide and, consequently, are the target of manifold disease prevention strategies. During the early, larval stages of development, Vibrio species are a common cause of high mortality rates in reared fish and shellfish, circumstances under which the host organisms might be highly susceptible to disease preventive or treatment strategies such as vaccines and antibiotics use, respectively. Regardless of host developmental stage, Vibrio infections may occur suddenly and can lead to the loss of the entire population reared in a given aquaculture system. Furthermore, the frequency of Vibrio-associated diseases in humans is increasing globally and has been linked to anthropic activities, in particular human-driven climate change and intensive livestock production. In this context, here we cover the current knowledge of Vibrio infections in fish aquaculture, with a focus on the model species gilthead seabream (Sparus aurata), a highly valuable reared fish in the Mediterranean climatic zone. Molecular methods currently used for fast detection and identification of Vibrio pathogens and their antibiotic resistance profiles are addressed. Targeted therapeutic approaches are critically examined. They include vaccination, phage therapy and probiotics supplementation, which bear promise in supressing vibriosis in land-based fish rearing and in mitigating possible threats to human health and the environment. This literature review suggests that antibiotic resistance is increasing among Vibrio species, with the use of probiotics constituting a promising, sustainable approach to prevent Vibrio infections in aquaculture.

Biomimetic Nanosponges Enable the Detoxification of Vibrio vulnificus Hemolysin

Vibrio vulnificus (V. vulnificus) infection-associated multiple antibiotic resistance has raised serious public health concerns. Recently, nanosponges (NSs) have been expected to provide innovative platforms for addressing antibacterial and drug-resistant challenges by targeting various pore-forming toxins (PFTs). In the present study, we constructed NSs to explore the effects and possible mechanism of recombinant V. vulnificus hemolysin (rVvhA)-induced injuries. In vitro, NSs significantly reversed rVvhA-induced apoptosis and necrosis, and improved toxin-induced intracellular reactive oxygen species (ROS) production, adenosine triphosphate (ATP) depletion, and apoptosis signaling pathway disruption. To explore the clinical translation potential of NSs, we established VvhA-induced septicemia and wound infection mouse models, respectively, and further found NSs could notably attenuate rVvhA-induced acute toxicity and septicemia-associated inflammation, as well as local tissue damage. In a conclusion, NSs showed excellent protective effects against rVvhA-induced toxicity, thus providing useful insights into addressing the rising threats of severe V. vulnificus infections.

Antibiogram signatures of Vibrio species recovered from surface waters in South Western districts of Uganda: Implications for environmental pollution and infection control

Reports of vibriosis and other related gastrointestinal infections have remained a recurring concern in the diverse global continent. The safety of drinking surface water and associated environmental pollution has remained a public health concern in limited resource sittings. Seen in this light, we report the antibiogram signatures of Vibrio species recovered from surface waters in the South-Western districts of Uganda. Surface water samples were collected for four months for Vibrio species isolation in four districts (Bushenyi-B, Mitooma-M, Rubirizi-R, and Sheema-S) using bacteria culture procedures, disc diffusion and Polymerase Chain Reaction (PCR) technique. Isolates were characterised, and the antibiotic fingerprints were determined using PCR and nine selected antibiotics in routine use. A total of 392 Vibrio species were confirmed from the various districts (B: 172, M: 79. R: 60, S: 81), with 163 (94.77%) resistant to colistin (polymixin), 145 (84.3%) resistant to cefotaxime, 127 (73.84%) resistant to azithromycin, and 33 (19.19%) resistant to chloramphenicol among Bushenyi isolates. A similar high resistance to fluoroquinolones and carbapenem antibiotics were also recorded in other districts of the study area. A complete multiple antibiotic resistance phenotype ((M)ARPs) to the applied antibiotics (A-CTX-CXM-MEM-ATH-K-TM-C-PB-NI-CIP-NA) were also recorded among some isolates, which produced multiple antibiotic resistance indexes of 1, suggesting a high-risk source of contamination due to the usage of several antibiotics. The PCR reports also confirm ampC gene {20 (10.9%)}, beta-lactamase TEM gene (blaTEM2), {30 (10%)} and dihydropteroate synthase type-1 and 11 gene (sul 1 & 11) {16 (8%)}. The results present an implicated environmental pollution problem and a potential concern to public health, therefore there is the need for control of such infectious bacteria and environmental pollution monitoring. Hence, it is recommended various approaches crucial to monitoring of emerging trends in drug resistance at the local and international levels.

WSES/GAIS/WSIS/SIS-E/AAST global clinical pathways for patients with skin and soft tissue infections

Skin and soft-tissue infections (SSTIs) encompass a variety of pathological conditions that involve the skin and underlying subcutaneous tissue, fascia, or muscle, ranging from simple superficial infections to severe necrotizing infections.Together, the World Society of Emergency Surgery, the Global Alliance for Infections in Surgery, the Surgical Infection Society-Europe, The World Surgical Infection Society, and the American Association for the Surgery of Trauma have jointly completed an international multi-society document to promote global standards of care in SSTIs guiding clinicians by describing reasonable approaches to the management of SSTIs.An extensive non-systematic review was conducted using the PubMed and MEDLINE databases, limited to the English language. The resulting evidence was shared by an international task force with different clinical backgrounds.

A Novel Cooperative Metallo-β-Lactamase Fold Metallohydrolase from Pathogen Vibrio vulnificus Exhibits β-Lactam Antibiotic-Degrading Activities

Vibrio vulnificus is a pathogen that accounts for one of the highest mortality rates and is responsible for most reported seafood-related illnesses and deaths worldwide. Owing to the threats of pathogens with β-lactamase activity, it is important to identify and characterize β-lactamases with clinical significance. In this study, the protein sequence of the metallo-β-lactamase (MBL) fold metallohydrolase from V. vulnificus (designated Vmh) was analyzed, and its oligomeric state, β-lactamase activity, and metal binding ability were determined. BLASTp analysis indicated that the V. vulnificus Vmh protein showed no significant sequence identity with any experimentally identified Ambler class B MBLs or enzymes containing the MBL protein fold; it was also predicted to have a signal peptide of 19 amino acids at its N terminus and an MBL protein fold from amino acid residues 23 to 216. Recombinant V. vulnificus Vmh protein was overexpressed and purified. Analytical ultracentrifugation and electrospray ionization-mass spectrometry (MS) data demonstrated its monomeric state in an aqueous solution. Recombinant V. vulnificus Vmh protein showed broad degrading activities against β-lactam antibiotics, such as penicillins, cephalosporins, and imipenems, with k_cat/K_m values ranging from 6.23 × 10² to 1.02 × 10⁴ M^-1 s^-1. The kinetic reactions of this enzyme exhibited sigmoidal behavior, suggesting the possibility of cooperativity. Zinc ions were required for the enzyme activity, which was abolished by adding the metal chelator EDTA. Inductively coupled plasma-MS indicated that this enzyme might bind two zinc ions per molecule as a cofactor.

Improved Method for Transformation of Vibrio vulnificus by Electroporation

Vibrio vulnificus, an emergent human pathogen, causes fulminant septicemia with a mortality rate of over 50%. Unlike for other pathogenic Vibrio species, the factors to conclusively indicate the virulence potential of V. vulnificus strains remain largely unknown. Understanding the pathogenesis of this bacterium at a molecular level is severely hindered by inefficiencies in transformation, for instance, due to the presence of a periplasmic nuclease, Vvn. Currently, successful transformation of V. vulnificus is nearly impossible due to lack of mobilizable plasmids for the bacterium, requiring (i) very high DNA concentrations, (ii) plasmid linearization, (iii) development of novel V. vulnificus-derived plasmids, or (iv) time-consuming conjugation-based methods. To overcome these limitations, we describe a rapid, efficient, and reproducible electroporation protocol to effectively transform widely available plasmids, with different copy numbers and antibiotic resistances, into phylogenetically distant strains of V. vulnificus. Cells are made competent in high concentrations of sucrose devoid of cations and recovered from electroporation using a high-salinity recovery medium. Compared to existing methods for transformation of V. vulnificus, significantly higher efficiencies are obtained using this improved protocol. Rapid and effective transformations can markedly improve molecular analyses of V. vulnificus leading to a greater understanding of its virulence potential. This is crucial to develop rapid detection methods which have the potential to prevent future outbreaks. The electroporation protocol described here may be particularly useful for optimizing transformation of other nuclease-producing bacteria. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Preparation of competent cells Basic Protocol 2: Transformation of cells by electroporation.

Analyzing Possible Native Functions of the Quinolone Resistance Gene qnr in Vibrio vulnificus

The worldwide distribution of qnr genes found on plasmids and their presence on the chromosomes of aquatic bacteria, such as Vibrio vulnificus, one of the suspected sources, suggests an origin before the development of synthetic quinolones. However, their native function remains unknown. Previous work indicated that expression of qnrVv in V. vulnificus was induced by cold shock. To investigate its role further, we constructed single in-frame deletion mutants in qnrVv and cspA (the gene for cold shock protein) and a double mutant in qnrVv and cspA in V. vulnificus ATCC 17562 to evaluate the response to different environmental conditions and stresses and to exposure to various DNA-damaging agents. We found that qnrVv is involved in resistance to ciprofloxacin, levofloxacin, and mitomycin C and in the cold shock response in V. vulnificus Moreover, ΔqnrVv and ΔcspA mutants showed slower growth when they were treated with bile salts at 37°C and then shifted to 15°C (cold shock) without bile salts in the medium, with the effect being stronger in the double mutant. This transition may mimic what happens when V. vulnificus is ingested into the gastrointestinal tract and released in its natural environment. Cold shock and bile salts induced the expression of cspA and DNA gyrase and topoisomerase IV genes. However, no induction was found in the ΔqnrVv mutant, suggesting that the qnrVv gene is involved in the response to DNA damage and nucleic acid secondary structure.

Protective Effects of Chicken Egg Yolk Immunoglobulins (IgYs) against Vibrio vulnificus Infections

Vibrio (V.) vulnificus infection is a rare disease whose death rates exceed 50% despite aggressive antibiotic treatment and surgical debridement. The aim of this study was to assess the ability of specific anti-V. vulnificus immunoglobulins Y (IgYs) for preventing and treating V. vulnificus infections. IgYs were produced by immunizing egg laying hens with inactivated whole cell bacteria. Peritoneal cytokines, blood's bacterial load, and survival curves were obtained from both prophylactic and therapeutic mouse models. The results showed that the specific IgYs (i) inhibited the growth of V. vulnificus in vitro, (ii) dramatically reduced the inflammatory response and blood's bacterial load, and (iii) improved the survival rate of V. vulnificus-infected mice. These results prove that anti-V. vulnificus IgYs can be markedly effective means for the prophylaxis and the therapy of V. vulnificus infections.

Phage therapy as a potential approach in the biocontrol of pathogenic bacteria associated with shellfish consumption

Infectious human diseases acquired from bivalve shellfish consumption constitute a public health threat. These health threats are largely related to the filter-feeding phenomenon, by which bivalve organisms retain and concentrate pathogenic bacteria from their surrounding waters. Even after depuration, bivalve shellfish are still involved in outbreaks caused by pathogenic bacteria, which increases the demand for new and efficient strategies to control transmission of shellfish infection. Bacteriophage (or phage) therapy represents a promising, tailor-made approach to control human pathogens in bivalves, but its success depends on a deep understanding of several factors that include the bacterial communities present in the harvesting waters, the appropriate selection of phage particles, the multiplicity of infection that produces the best bacterial inactivation, chemical and physical factors, the emergence of phage-resistant bacterial mutants and the life cycle of bivalves. This review discusses the need to advance phage therapy research for bivalve decontamination, highlighting their efficiency as an antimicrobial strategy and identifying critical aspects to successfully apply this therapy to control human pathogens associated with bivalve consumption.

[Vibrio vulnificus, an increasing threat of sepsis in Germany?]

BACKGROUND

The prevalence of Vibrio vulnificus heavily depends on the temperature and salinity of the sea water. In the course of climate change an increase in cases of fatal sepsis caused by V. vulnificus at the German Baltic Sea coast could be detected.

OBJECTIVE

To generate awareness for a life-threatening infection with increasing incidence in Germany.

MATERIAL AND METHODS

This article presents an overview of the current state of the literature followed by an exemplary description of cases with V vulnificus sepsis caused by contact with water in the Baltic Sea, which were treated at the Medical University in Greifswald in summer 2018.

RESULTS

In the presence of risk factors, such as liver and kidney diseases, immunosuppression and male sex, there is a danger of severe sepsis if damaged skin comes into contact with contaminated sea water. A pronounced organ dysfunction can frequently be found on admission. In these cases the diagnosis must be made promptly and timely surgical cleansing and antibiotic treatment should be initiated (e.g. a combination of tetracyclines and third generation cephalosporins).

CONCLUSION

Sepsis due to V. vulnificus will probably increase over the coming years. Because there is a latency in some cases between infection and onset of sepsis, physicians beyond the coastal region must also be informed about this disease.

Septicemia secondary to Vibrio cholerae (non-O1/non-O139) in wound

A 63-year-old woman with a prior history of chronic lower extremity lymphedema came to the hospital for evaluation of new-onset left leg pain and swelling associated with haemorrhagic blisters and foul-smelling discharge. Relevant history included a recent trip to a Hudson River Valley beach in New York 1 week prior to hospitalisation. Laboratory evaluation revealed significant leukocytosis and lactic acidosis. She was found to have sepsis and bacteremia secondary to Vibrio cholerae (serotype non-O1, non-O139). During a prolonged intensive care unit course requiring intravenous pressor support and broad-spectrum antibiotics, she underwent debridement of her left foot eschar along with skin grafting. Once clinically stable and improved, she was discharged to a subacute rehabilitation centre with close follow-up for wound care. V. cholerae infection is rare and often benign but can be transmitted from contaminated seawater to individuals with underlying chronic illness and cause severe symptoms, including sepsis.