Bacterial communities associated with tail fan necrosis in spiny lobster, Jasus edwardsii

Tail Fan Necrosis syndrome in decapod crustaceans: A review

Lobsters and crayfish in Australasia can develop a condition known as Tail Fan Necrosis (TFN syndrome). Many attempts have been made to find a primary pathogen or link the syndrome to commercial activities, but a solution remains elusive. TFN syndrome is a 'wicked problem', a problem difficult or impossible to solve because of incomplete and contradictory information forming a matrix of potential outcomes with no simple solution. Reviewing the literature shows TFN syndrome is sometimes reported to develop in association with sterile blisters on the telson and uropods which may rupture permitting invasion by environmental fungal and/or bacterial flora. Whether blisters form prior to, or because of, infection is unknown. TFN syndrome sometimes develops in captivity, sometimes requires a previous insult to the telson and uropods, and prevalence is patchy in the wild. The literature shows the cause of blisters associated with TFN syndrome remains an enigma, for which we suggest several possible initiating factors. We strongly urge that researchers not 'jump to conclusions' as to the aetiology of TFN syndrome. It cannot be explained without carefully exploring alternative aetiologies whilst being cognisant of the age-old lesson that 'correlation does not equal causation'.

Differences in diversity and community composition of the shell microbiome of apparently healthy lobsters Homarus americanus across Atlantic Canada

Host-microbe dynamics are of increasing interest in marine research due to their role in host health and productivity. Changes in the shell microbiome of American lobsters have been associated with epizootic shell disease, a syndrome that is spreading northwards across the eastern U.S. and Canadian Atlantic coast. This study analyzed differences in alpha and beta diversity, as well as differentially abundant taxa, in the shell-associated bacterial community of apparently healthy lobsters from four lobster fishing areas (LFAs) in Atlantic Canada. Over 180 lobsters from New Brunswick, Nova Scotia and Prince Edward Island (PEI) were sampled during seven sampling events over four sampling months. The bacterial community was identified using novel PacBio long-read sequencing, while alpha and beta diversity parameters were analyzed using linear regression models and weighted UniFrac distances. The bacterial richness, diversity and evenness differed by sampling location, sampling month, and molt stage, but not by lobster sex or size, nor sampling depth. Similarly, based on LFA, sampling month, year and lobster molt stage, the shell microbiome differed in microbial community composition with up to 34 out of 162 taxa differing significantly in abundance between sampling groups. This large-scale microbial survey suggests that the shell microbial diversity of apparently healthy lobsters is influenced by spatial and temporal factors such as geographic location, as well as the length of time the carapace is exposed to the surrounding seawater.

Long-read sequencing reveals the shell microbiome of apparently healthy American lobsters Homarus americanus from Atlantic Canada

The shell microbial community of lobsters-a key factor in the development of epizootic shell disease (ESD)-is still insufficiently researched in Atlantic Canada and many knowledge gaps remain. This study aimed to establish a baseline description and analysis of the shell microbiome of apparently healthy lobsters from four locations in the region. More than 180 lobster shell swab samples were collected from New Brunswick, Nova Scotia and Prince Edward Island (PEI). PacBio long-read 16S rDNA sequencing and bioinformatic analyses in QIIME2 identified the shell-associated bacteria. The shell microbiome of healthy lobsters consisted mainly of the bacterial classes Gammaproteobacteria, Saprospiria, Verrucomicrobiae, Alphaproteobacteria, Flavobacteriia, Acidimicrobiia and Planctomycetia. The microbial composition differed regionally and seasonally, with some classes showing decreased or increased relative abundances in the PEI samples as well as in the winter and spring samples in Nova Scotia. The core shell microbiome included potentially pathogenic as well as beneficial bacterial taxa, of which some were present only in certain regions. Bacterial taxa that have previously been associated with ESD were present on healthy lobsters in Atlantic Canada, but their frequency differed by location, sampling time, and moult stage. This study indicated that geographical and seasonal factors influenced the shell microbiome of apparently healthy lobsters more than host factors such as sex, size, and moult stage. Our results provide valuable reference microbial data from lobsters in a disease-free state.

Shell disease syndromes of decapod crustaceans

The term shell disease subsumes a number of debilitating conditions affecting the outer integument (the carapace) of decapod crustaceans, such as lobsters and crabs. Herein, we seek to find commonality in the aetiology and pathology of such conditions, and those cases that result in the progressive erosion of the cuticle through to the visceral tissues by a cocktail of microbial-derived enzymes including lipases, proteases and chitinases. Aquimarina spp. are involved in shell disease in many different crustaceans across a wide geographical area, but the overall view is that the condition is polymicrobial in nature leading to dysbiosis within the microbial consortium of the damaged cuticle. The role of environment, decapod behaviour and physiology in triggering this disease is also reviewed. Finally, we provide a conceptual model for disease aetiology and suggest several avenues for future research that could improve our understanding of how such factors trigger, or exacerbate, this condition.

Microbial Spectrum and Antibiotic Sensitivity Pattern of Bacteria Isolated from the Spiny Lobster, Panulirus regius (De Brito Capello, 1864)

Microbial spectrum and antibiogram of bacteria isolated from Panulirus regius of the coast of Lagos were analysed using standard techniques. The lobster head had higher total bacteria and total coliform counts with respective significant (P < 0.05) values of 4.17 x 106 ± 1.46 CFU g−1 and 3.06 x 103 ± 1.56 CFU g−1. A higher total fungi count (2.99 x 102 ± 1.63) was recorded in the lobster tail. In the bacterial group, Bacilus megaterium had the highest frequency of occurrence (22.6%) while in the fungal group, Aspergillus niger had the highest frequency of occurrence (20.0%). All isolates were sensitive to ciprofloxacin and showed resistance to rocephin and zinnacef except Micrococcus sp. and Salmonella sp. The presence of antibiotic-resistant bacteria from the lobsters is a serious concern.

Multiple Intestinal Bacteria Associated with the Better Protective Effect of Bifidobacterium pseudocatenulatum LI09 against Rat Liver Injury

Bifidobacterium pseudocatenulatum LI09 could protect rats from D-galactosamine- (D-GalN-) induced liver injury. However, individual difference in the protective effects of LI09 on the liver injury remains poorly understood. The present study is aimed at determining the multiple intestinal bacteria associated with the better protective effect of LI09 against D-GalN-induced rat liver injury. Two rat cohorts, i.e., the nonsevere and severe cohorts, were divided based on their liver injury severity. Higher level of ALB and lower levels of ALT, AST, TBA, TB, IL-5, and MIP-3α were determined in the nonsevere cohort than the severe cohort. The alpha diversity indices (i.e., observed species, Shannon, and Pielou indices) did not yield significant differences between the intestinal microbiota of the nonsevere and severe cohorts. The intestinal microbiota composition was different between the two cohorts. Ten phylotypes assigned to Bacteroides, Clostridia_UCG-014, Clostridium Lachnospiraceae, Lachnospiraceae_NK4A136, and Parabacteroides were closely associated with the nonsevere cohort, among which, ASV8_Lachnospiraceae_NK4A136 was the most associated one. At the structure level, two groups of phylotypes with most correlations were determined in the intestinal microbiota networks of the two cohorts. Among them, ASV135_Lachnospiraceae_NK4A136 was the most powerful gatekeeper in the microbiota network of the nonsevere cohort. In conclusion, some intestinal bacteria, e.g., Lachnospiraceae_NK4A136, Parabacteroides, and Clostridium, were associated with the better protective effect of LI09 against D-GalN-induced rat liver injury. They were likely to enhance the effectiveness of LI09, and their clinical application deserves further investigation.

Multiple bacteria associated with the more dysbiotic genitourinary microbiomes in patients with type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) influences the human health and can cause significant illnesses. The genitourinary microbiome profiles in the T2DM patients remain poorly understood. In the current study, a series of bioinformatic and statistical analyses were carried out to determine the multiple bacteria associated with the more dysbiotic genitourinary microbiomes (i.e., those with lower dysbiosis ratio) in T2DM patients, which were sequenced by Illumina-based 16S rRNA gene amplicon sequencing. All the genitourinary microbiomes from 70 patients with T2DM were clustered into three clusters of microbiome profiles, i.e., Cluster_1_T2DM, Cluster_2_T2DM and Cluster_3_T2DM, with Cluster_3_T2DM at the most dysbiotic genitourinary microbial status. The three clustered T2DM microbiomes were determined with different levels of alpha diversity indices, and driven by distinct urinalysis variables. OTU12_Clostridiales and OTU28_Oscillospira were likely to drive the T2DM microbiomes to more dysbiotic status, while OTU34_Finegoldia could play a vital role in maintaining the least dysbiotic T2DM microbiome (i.e., Cluster_1_T2DM). The functional metabolites K08300_ribonuclease E, K01223_6-phospho-beta-glucosidase and K00029_malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+) were most associated with Cluster_1_T2DM, Cluster_2_T2DM and Cluster_3_T2DM, respectively. The characteristics and multiple bacteria associated with the more dysbiotic genitourinary microbiomes in T2DM patients may help with the better diagnosis and management of genitourinary dysbiosis in T2DM patients.

Recovery Dynamics of Intestinal Bacterial Communities of CCl4-Treated Mice with or without Mesenchymal Stem Cell Transplantation over Different Time Points

Liver injury has caused significant illness in humans worldwide. The dynamics of intestinal bacterial communities associated with natural recovery and therapy for CCl4-treated liver injury remain poorly understood. This study was designed to determine the recovery dynamics of intestinal bacterial communities in CCl4-treated mice with or without mesenchymal stem cell transplantation (i.e., MSC and CCl4 groups) at 48 h, 1 week (w), and 2 w. MSCs significantly improved the histopathology, survival rate, and intestinal structural integrity in the treated mice. The gut bacterial communities were determined with significant changes in both the MSC and CCl4 groups over time, with the greatest difference between the MSC and CCl4 groups at 48 h. The liver injury dysbiosis ratio experienced a decrease in the MSC groups and a rise in the CCl4 groups over time, suggesting the mice in the MSC group at 48 h and the CCl4 group at two weeks were at the least gut microbial dysbiosis status among the corresponding cohorts. Multiple OTUs and functional categories were associated with each of the bacterial communities in the MSC and CCl4 groups over time. Among these gut phylotypes, OTU1352_S24-7 was determined as the vital member in MSC-treated mice at 48 h, while OTU453_S24-7, OTU1213_Ruminococcaceae, and OTU841_Ruminococcus were determined as the vital phylotypes in CCl4-treated mice at two weeks. The relevant findings could assist the diagnosis of the microbial dysbiosis status of intestinal bacterial communities in the CCl4-treated cohorts with or without MSC transplantation.

Post-mortem examination of the Caribbean spiny lobster (Panulirus argus, Latreille 1804) and pathology in a fishery of the Lesser Antilles

The Caribbean spiny lobster, Panulirus argus (Latreille, 1804) is a highly commercial species and comprises the largest spiny lobster fishery in the world. Although populations have declined throughout its range, there is little known regarding its diseases and pathogens. The objectives of this study were to provide illustrated and standardized methods for postmortem examination, and to describe baseline gross and microscopic pathology for P. argus. From July 2017-March 2019, a postmortem examination including comprehensive histological assessment was performed on 313 fishery-caught lobsters. Epibionts and lesions observed include branchial cirriped infestation (69%), branchial encysted nemertean worm larvae (23%), tail fan necrosis (11%), skeletal muscle necrosis (7%), antennal gland calculi (6%), branchial infarction (2%), and microsporidiosis (0.6%). This report confirms the rare prevalence of microsporidiosis in P. argus and describes nemertean worm larvae in the gill. This study also reports a condition resembling excretory calcinosis in spiny lobster. The methods and data produced by this study facilitate disease diagnosis and sustainable stock management of P. argus.

Vital Members in the More Dysbiotic Oropharyngeal Microbiotas in H7N9-Infected Patients

The dysbiosis of oropharyngeal (OP) microbiota is associated with multiple diseases, including H7N9 infection. Different OP microbial colonization states may reflect different severities or stages of disease and affect the effectiveness of the treatments. Current study aims to determine the vital bacteria that could possibly drive the OP microbiota in the H7N9 patients to more severe microbial dysbiosis state. The OP microbiotas of 42 H7N9 patients and 30 healthy subjects were analyzed by a series of bioinformatics and statistical analyses. Two clusters of OP microbiotas in H7N9 patients, i.e., Cluster_1_Diseased and Cluster_2_Diseased, were determined at two microbial colonization states by Partition Around Medoids (PAM) clustering analysis, each characterized by distinct operational taxonomic units (OTUs) and functional metabolites. Cluster_1_Diseased was determined at more severe dysbiosis status compared with Cluster_2_Diseased, while OTU143_Capnocytophaga and OTU269_Treponema acted as gatekeepers for both of the two clustered microbiotas. Nine OTUs assigned to seven taxa, i.e., Alloprevotella, Atopobium, Megasphaera, Oribacterium, Prevotella, Stomatobaculum, and Veillonella, were associated with both H7N9 patients with and without secondary bacterial lung infection in Cluster_1. In addition, two groups of healthy cohorts may have potential different susceptibilities to H7N9 infection. These findings suggest that two OP microbial colonization states of H7N9 patients were at different dysbiosis states, which may help determine the health status of H7N9 patients, as well as the susceptibility of healthy subjects to H7N9 infection.

Characteristics of three microbial colonization states in the duodenum of the cirrhotic patients

Aim: Investigation of characteristics of different duodenal microbial colonization states in patients with liver cirrhosis (LC). Materials & methods: Deep-sequencing analyses of the 16S rRNA gene V1-V3 regions were performed. Results: Both bacterial compositions and richness were different between the three-clustered LC microbiotas, in other words, Cluster_1_LC, Cluster_2_LC and Cluster_3_LC. Cluster_1_LC were more likely at severe dysbiosis status due to its lowest modified cirrhosis dysbiosis ratio. OTU12_Prevotella and OTU10_Comamonas were most associated with Cluster_1_LC and Cluster_3_LC, respectively, while OTU38_Alloprevotella was vital in Cluster_2_LC. Pyruvate-ferredoxin/flavodoxin oxidoreductase, dihydroorotate dehydrogenase and branched-chain amino acid transport system substrate-binding protein were most associated with Cluster_1_LC, Cluster_2_LC and Cluster_3_LC, respectively. Conclusion: The three duodenal microbial colonization states had distinct representative characteristics, which might reflect the health status of cirrhotic patients.