First European case of gastroenteritis and bacteremia due to Vibrio hollisae

Grimontia hollisae Sepsis in a 9-Month-Old Female Infant: A Case Report

Grimontia hollisae, an uncommon cause of sepsis, was identified in a 9-month-old infant in Africa without confirmed seafood consumption. Prompt diagnosis through blood culture and targeted antibiotic therapy ensured recovery, emphasizing the need for increased awareness, enhanced diagnostic tools, and active monitoring of emerging pathogens in tropical and resource-limited regions. We present a case report involving a 9-month-old infant who exhibited symptoms of acute gastroenteritis. The blood culture revealed G. hollisae. We treated the infant on empirical first-line antibiotics of IV ceftriaxone, IV gentamicin, zinc tablets, and syrup paracetamol for 5 days after which the child was discharged on oral metronidazole following resolution of symptoms. This case highlights the importance of G. hollisae in causing sepsis in infants in tropical settings. It also emphasizes the need for blood culture investigation and administering the appropriate antibiotics in the diagnosis of children presenting with suspected sepsis.

Public health aspects of Vibrio spp. related to the consumption of seafood in the EU

Vibrio parahaemolyticus, Vibrio vulnificus and non-O1/non-O139 Vibrio cholerae are the Vibrio spp. of highest relevance for public health in the EU through seafood consumption. Infection with V. parahaemolyticus is associated with the haemolysins thermostable direct haemolysin (TDH) and TDH-related haemolysin (TRH) and mainly leads to acute gastroenteritis. V. vulnificus infections can lead to sepsis and death in susceptible individuals. V. cholerae non-O1/non-O139 can cause mild gastroenteritis or lead to severe infections, including sepsis, in susceptible individuals. The pooled prevalence estimate in seafood is 19.6% (95% CI 13.7-27.4), 6.1% (95% CI 3.0-11.8) and 4.1% (95% CI 2.4-6.9) for V. parahaemolyticus, V. vulnificus and non-choleragenic V. cholerae, respectively. Approximately one out of five V. parahaemolyticus-positive samples contain pathogenic strains. A large spectrum of antimicrobial resistances, some of which are intrinsic, has been found in vibrios isolated from seafood or food-borne infections in Europe. Genes conferring resistance to medically important antimicrobials and associated with mobile genetic elements are increasingly detected in vibrios. Temperature and salinity are the most relevant drivers for Vibrio abundance in the aquatic environment. It is anticipated that the occurrence and levels of the relevant Vibrio spp. in seafood will increase in response to coastal warming and extreme weather events, especially in low-salinity/brackish waters. While some measures, like high-pressure processing, irradiation or depuration reduce the levels of Vibrio spp. in seafood, maintaining the cold chain is important to prevent their growth. Available risk assessments addressed V. parahaemolyticus in various types of seafood and V. vulnificus in raw oysters and octopus. A quantitative microbiological risk assessment relevant in an EU context would be V. parahaemolyticus in bivalve molluscs (oysters), evaluating the effect of mitigations, especially in a climate change scenario. Knowledge gaps related to Vibrio spp. in seafood and aquatic environments are identified and future research needs are prioritised.

Occurrence of Vibrio spp. along the Algerian Mediterranean coast in wild and farmed Sparus aurata and Dicentrarchus labrax

Background and Aim:

Vibrio bacteria are autochthonous inhabitants of aquatic and marine environments. Certain strains are responsible for important seafood-borne outbreaks in developed nations. The aim of this study was to investigate the occurrence of Vibrio spp. along the Algerian Mediterranean coast in several samples of two prominent wild and farmed marine fishes, Sparus aurata and Dicentrarchus labrax.

Materials and Methods:

A total of 350 S. aurata (n=280 farmed and n=70 wild) and 340 D. labrax (n=250 farmed and n=90 wild) were sampled among three different locations along the Algerian Mediterranean coastal area. The samples were processed for Vibrio research according to the ISO methods. Isolated colonies were identified utilizing biochemical tests and consecutively confirmed with matrix-assisted laser desorption ionization-time-of-flight mass spectrometry, combined with polymerase chain reaction (PCR) analysis when appropriate, or confirmed with PCR analysis alone.

Results:

A total of 42 Vibrio spp. were detected only among the farmed fishes. Taking into account, all 690 fishes sampled, the incidence of Vibrio spp. was 6.08% (with peaks up to 7.92%) among the total number of farmed fishes. Overall, 25 strains were isolated from S. aurata and 17 strains were isolated from D. labrax. The isolated strains belonged to four different species and were represented as follows: Vibrio alginolyticus (n=20), Vibrio cholerae (n=15), Vibrio fluvialis (n=5), and Vibrio hollisae (n=2). The incidence of Vibrio was higher in places characterized by greater levels of anthropogenic contamination of seawater.

Conclusion:

Considering the growing production and consequent rising consumption of farmed fish in Algeria, the reported incidence of Vibrio and the presence of potentially pathogenic strains of Vibrio such as V. cholerae cause particular concern for food safety matters. Even if innovative and natural techniques are desired in aquaculture, proper hygiene and manufacturing practices are essential for the correct management of Vibrio infection risk in farmed fishes at both industrial and domestic levels.

Dangerous hitchhikers? Evidence for potentially pathogenic Vibrio spp. on microplastic particles

The taxonomic composition of biofilms on marine microplastics is widely unknown. Recent sequencing results indicate that potentially pathogenic Vibrio spp. might be present on floating microplastics. Hence, these particles might function as vectors for the dispersal of pathogens. Microplastics and water samples collected in the North and Baltic Sea were subjected to selective enrichment for pathogenic Vibrio species. Bacterial colonies were isolated from CHROMagar™Vibrio and assigned to Vibrio spp. on the species level by MALDI-TOF MS (Matrix Assisted Laser Desorption/Ionisation - Time of Flight Mass Spectrometry). Respective polymers were identified by ATR FT-IR (Attenuated Total Reflectance Fourier Transform - Infrared Spectroscopy). We discovered potentially pathogenic Vibrio parahaemolyticus on a number of microplastic particles, e.g. polyethylene, polypropylene and polystyrene from North/Baltic Sea. This study confirms the indicated occurrence of potentially pathogenic bacteria on marine microplastics and highlights the urgent need for detailed biogeographical analyses of marine microplastics.

Practical Guidance for Clinical Microbiology Laboratories: Diagnosis of Bacterial Gastroenteritis

Bacterial gastroenteritis is a disease that is pervasive in both the developing and developed worlds. While for the most part bacterial gastroenteritis is self-limiting, identification of an etiological agent by bacterial stool culture is required for the management of patients with severe or prolonged diarrhea, symptoms consistent with invasive disease, or a history that may predict a complicated course of disease. Importantly, characterization of bacterial enteropathogens from stool cultures in clinical laboratories is one of the primary means by which public health officials identify and track outbreaks of bacterial gastroenteritis. This article provides guidance for clinical microbiology laboratories that perform stool cultures. The general characteristics, epidemiology, and clinical manifestations of key bacterial enteropathogens are summarized. Information regarding optimal specimen collection, transport, and processing and current diagnostic tests and testing algorithms is provided. This article is an update of Cumitech 12A (P. H. Gilligan, J. M. Janda, M. A. Karmali, and J. M. Miller, Cumitech 12A, Laboratory diagnosis of bacterial diarrhea, 1992).

The thermostable direct hemolysin from Grimontia hollisae causes acute hepatotoxicity in vitro and in vivo

Background

G. hollisae thermostable direct hemolysin (Gh-TDH) is produced by most strains of G. hollisae. This toxin has been reported to be absorbed in the intestines in humans. Secondary liver injury might be caused by venous return of the toxin through the portal system. We aimed to firstly analyze the in vitro and in vivo hepatotoxicity of Gh-TDH.

Methods

Liver cells (primary human non-cancer cell and FL83B mouse cells) were treated and mice (BALB/c) were fed with this toxin to investigate its hepatotoxicity. Morphological examination and cytotoxicity assays using liver cells were also performed. Fluorescein isothiocyanate-conjugated toxin was used to analyze the localization of this protein in liver cells. Mice were subjected to liver function measurements and liver biopsies following toxin treatment and wild-type bacterial infection. PET (positron emission tomography)/CT (computed tomography) images were taken to assess liver metabolism during acute injury and recovery.

Results

The effect of hepatotoxicity was dose and time dependent. Cellular localization showed that the toxin was initially located around the cellular margins and subsequently entered the nucleus. Liver function measurements and liver biopsies of the mice following treatment with toxin or infection with wild-type Grimontia hollisae showed elevated levels of transaminases and damage to the periportal area, respectively. The PET/CT images revealed that the reconstruction of the liver continued for at least one week after exposure to a single dose of the toxin or bacterial infection.

Conclusions

The hepatotoxicity of Gh-TDH was firstly demonstrated. The damage was located in the periportal area of the liver, and the liver became functionally insufficient.

Site-directed mutations of thermostable direct hemolysin from Grimontia hollisae alter its arrhenius effect and biophysical properties

Recombinant thermostable direct hemolysin from Grimontia hollisae (Gh-rTDH) exhibits paradoxical Arrhenius effect, where the hemolytic activity is inactivated by heating at 60 °C but is reactivated by additional heating above 80 °C. This study investigated individual or collective mutational effect of Tyr53, Thr59, and Ser63 positions of Gh-rTDH on hemolytic activity, Arrhenius effect, and biophysical properties. In contrast to the Gh-rTDH wild-type (Gh-rTDH(WT)) protein, a 2-fold decrease of hemolytic activity and alteration of Arrhenius effect could be detected from the Gh-rTDH(Y53H/T59I) and Gh-rTDH(T59I/S63T) double-mutants and the Gh-rTDH(Y53H/T59I/S63T) triple-mutant. Differential scanning calorimetry results showed that the Arrhenius effect-loss and -retaining mutants consistently exhibited higher and lower endothermic transition temperatures, respectively, than that of the Gh-rTDH(WT). Circular dichroism measurements of Gh-rTDH(WT) and Gh-rTDH(mut) showed a conspicuous change from a β-sheet to α-helix structure around the endothermic transition temperature. Consistent with the observation is the conformational change of the proteins from native globular form into fibrillar form, as determined by Congo red experiments and transmission electron microscopy.

Chlorophyll a might structure a community of potentially pathogenic culturable Vibrionaceae. Insights from a one-year study of water and mussels surveyed on the French Atlantic coast

The present study focused on the isolation of culturable bacteria from mussels and sea water to identify Vibrionaceae potentially pathogenic for humans. Three sites located on the French Atlantic coast were monitored monthly (twice each month during summer) for 1 year. Environmental parameters were surveyed (water temperature, salinity, turbidity, chlorophyll a) and bacteria were detected by culture and identified by API 20E(®) systems (BioMérieux) and PCR. A total of seven species were detected (Grimontia hollisae, Photobacterium damselae, Vibrio alginolyticus, V. cholerae, V. fluvialis, V. vulnificus and V. parahaemolyticus) and species diversity was higher at the end of summer. Surprisingly, V. cholerae non-O1/non-O139 was detected in spring. No site effect was detected. Using Sørensen similarity indices and statistical analyses, we showed that chlorophyll a had a significant influence on the bacterial community detected in mussels and assemblages were more similar to one another when chlorophyll a values were above 20 µg l(-1) . No significant effect of any parameter was found on the community detected in water samples. Such surveys are essential for the understanding of sanitary crises and detection of emerging pathogens.

Grimontia hollisae, a potential agent of gastroenteritis and bacteraemia in the Mediterranean area

Vibrio hollisae was first described in 1982 as an agent of diarrhoea and was reclassified in 2003 into a novel genus as Grimontia hollisae. We report the first case of G. hollisae bacteraemia in the Mediterranean area, in an 81-year-old man with a severe gastroenteritis and hepatitis following the consumption of raw oysters. The incidence of this micro-organism as an agent of gastroenteritis may be underestimated because it may not be detected using routine culture conditions.

Severe gastroenteritis and hypovolemic shock caused by Grimontia (Vibrio) hollisae infection

Vibrio hollisae is a halophilic species that was recently reclassified as Grimontia hollisae. This organism is known to cause moderate to severe cases of gastroenteritis. We report a case of an individual who suffered a more severe form of this disease, presenting with profound hypotension and acute renal failure, secondary to hypovolemic shock.

Rugosity in Grimontia hollisae

Grimontia hollisae, formerly Vibrio hollisae, produces both smooth and rugose colonial variants. The rugose colony phenotype is characterized by wrinkled colonies producing copious amounts of exopolysaccharide. Cells from a rugose colony grown at 30 degrees C form rugose colonies, while the same cells grown at 37 degrees C form smooth colonies, which are characterized by a nonwrinkled, uncrannied appearance. Stress response studies revealed that after exposure to bleach for 30 min, rugose survivors outnumbered smooth survivors. Light scatter information obtained by flow cytometry indicated that rugose cells clumped into clusters of three or more cells (average, five cells) and formed two major clusters, while smooth cells formed only one cluster of single cells or doublets. Fluorescent lectin-binding flow cytometry studies revealed that the percentages of rugose cells that bound either wheat germ agglutinin (WGA) or Galanthus nivalis lectin (GNL) were greater than the percentages of smooth cells that bound the same lectins (WGA, 35% versus 3.5%; GNL, 67% versus 0.21%). These results indicate that the rugose exopolysaccharide consists partially of N-acetylglucosamine and mannose. Rugose colonies produced significantly more biofilm material than did smooth colonies, and rugose colonies grown at 30 degrees C produced more biofilm material than rugose colonies grown at 37 degrees C. Ultrastructurally, rugose colonies show regional cellular differentiation, with apical and lateral colonial regions containing cells embedded in a matrix stained by Alcian Blue. The cells touching the agar surface are packed tightly together in a palisade-like manner. The central region of the colony contains irregularly arranged, fluid-filled spaces and loosely packed chains or arrays of coccoid and vibrioid cells. Smooth colonies, in contrast, are flattened, composed of vibrioid cells, and lack distinct regional cellular differences. Results from suckling mouse studies showed that both orally fed rugose and smooth variants elicited significant, but similar, amounts of fluid accumulated in the stomach and intestines. These observations comprise the first report of expression and characterization of rugosity by G. hollisae and raise the possibility that expression of rugose exopolysaccharide in this organism is regulated at least in part by growth temperature.

Infections related to the ingestion of seafood Part I: viral and bacterial infections

Foodborne diseases cause an estimated 76 million illnesses in the USA each year. Seafood is implicated in 10-19% of these illnesses. A causative agent can be traced in about 44% of seafood-related outbreaks, viruses accounting for around half of these illnesses. Although viruses are the most common cause of seafood-related infections, most hospitalisations and deaths are due to bacterial agents. A wide variety of viruses, bacteria, and parasites have been implicated in seafood-related outbreaks, which are reported worldwide. The factor most commonly associated with infection is consumption of raw or undercooked seafood. People with underlying disorders, particularly liver disease, are more susceptible to infection. The first part of this two-part review summarises the general incidence of seafood-related infections and discusses the common viral and bacterial causes of these infections. For each agent, the microbiology, epidemiology, mode of transmission, and treatment are discussed. In the May issue of the journal we will discuss parasites associated with seafood consumption, the safety of seafood, and the measures put in place in the USA to increase its safety.

Vibrio vulnificus septicaemia

Vibrio vulnificus is an opportunistic pathogen capable of causing a fulminant septicaemia in susceptible patients. Underlying chronic diseases such as liver impairment and immunosuppression are important factors contributing to the severity of the infection and outcome. Early suspicion and diagnosis with appropriate antibiotic therapy is important as delay can adversely affect outcome. For those who develop tissue necrotizing fasciitis, early surgical debridement is recommended to allow better penetration of antibiotics and also to reduce the severity of the septicaemia. Mortality is quoted as between 50% and 90%. Current antibiotic recommendations are intravenous ceftazidime 2 g tds and doxycycline 100 mg od.

Analysis of gyrB and toxR gene sequences of Vibrio hollisae and development of gyrB- and toxR-targeted PCR methods for isolation of V. hollisae from the environment and its identification

Isolation of Vibrio hollisae strains, particularly from the environment, is rare. This may be due, in part, to the difficulty encountered when using conventional biochemical tests to identify the microorganism. In this study, we evaluated whether two particular genes may be useful for the identification of V. hollisae. The two genes are presumed to be conserved among the bacterial species (gyrB) or among the species of the genus Vibrio (toxR). A portion of the gyrB sequence of V. hollisae was cloned by PCR using a set of degenerate primers. The sequence showed 80% identity with the corresponding Vibrio parahaemolyticus gyrB sequence. The toxR gene of V. hollisae was cloned utilizing a htpG gene probe derived from the V. parahaemolyticus htpG gene, which is known to be linked to the toxR gene in V. hollisae. The coding sequence of the cloned V. hollisae toxR gene had 59% identity with the V. parahaemolyticus toxR coding sequence. The results of DNA colony hybridization tests using the DNA probes derived from the two genes of V. hollisae indicated that these gene sequences could be utilized for differentiation of V. hollisae from other Vibrio species and from microorganisms found in marine fish. PCR methods targeting the two gene sequences were established. Both PCR methods were shown to specifically detect the respective target sequences of V. hollisae but not other organisms. A strain of V. hollisae added at a concentration of 1 to 10(2) CFU/ml to alkaline peptone water containing a seafood sample could be detected by a 4-h enrichment incubation in alkaline peptone water at 37 degrees C followed by quick DNA extraction with an extraction kit and 35-cycle PCR specific for the V. hollisae toxR gene. We conclude that screening of seafood samples by this 35-cycle, V. hollisae toxR-specific PCR, followed by isolation on a differential medium and identification by the above htpG- and toxR-targeted PCR methods, can be useful for isolation from the environment and identification of V. hollisae.