Neonatal Elizabethkingia anophelis meningitis originating from the water reservoir of an automated infant milk dispenser, the Netherlands, February 2024

Elizabethkingia anophelis is a multidrug-resistant pathogen causing high mortality and morbidity in adults with comorbidities and neonates. We report a Dutch case of E. anophelis meningitis in a neonate, clonally related to samples taken from an automated infant milk dispenser located at the family's residence. We inform about the emergence of E. anophelis and suggest molecular surveillance in hospitals and other health settings. This is the first case connecting an automated formula dispenser to an invasive infection in a neonate.

A case of Elizabethkingia meningoseptica septicemia

A 82-year-old man was admitted to hospital with fever, unresponsiveness, elevated hypersensitive C-reactive protein and neutrophile granulocyte. Ceftriaxone was administrated by intravenous dripping in the emergency room, but the effect was not satisfactory. Following his admission to the ward, cefoperazone sulbactam were given. Elizabethkingia meningoseptica was identified by blood culture and further confirmed by 16S rRNA sequencing. The lumbar puncture showed that cerebrospinal fluid pressure was 80 mmH2O (1 mmH2O=0.0098 kPa) and biochemical results were normal. After 11 days of cefoperazone sulbactam treatment, the patient was discharged with negative blood culture. The hypersensitive C-reactive protein and neutrophile granulocyte had also declined. The patient received levofloxacin tablets for anti-infection treatment for 14 d after discharge. No signs of infection were observed in three months' following up.

Elizabethkingia meningosepticum infections with varied presentations and different antimicrobial susceptibility - A case series

We report three sporadic infections by Elizabethkingia meningosepticum from Government Medical College Kozhikode in Kerala state, South India over a period of three years. Two cases were commenced in the community in immunocompromised children beyond the newborn period, but both recovered promptly. Another was a hospital-acquired meningitis in a newborn baby who developed neurologic sequelae. In contrast to widespread antimicrobial resistance exhibited by this pathogen, there was good susceptibility to commonly used antimicrobials such as ampicillin, cefotaxime, piperacillin, ciprofloxacin, and vancomycin. Whilst ß lactam antibiotics are found effective in the treatment of Elizabethkingia septicaemia of children, piperacillin-tazobactam, vancomycin combination seems effective empiric choice of antibiotics for neonatal meningitis due to Elizabethkingia; there is a need for guidelines for the management of this infection, especially in neonatal meningitis.

Isolation of Elizabethkingia spp. from Diagnostic Specimens from Dogs and Cats, United States, 2019-2021

We retrospectively reviewed Elizabethkingia spp. culture and susceptibility results from 86 veterinary diagnostic laboratory results from US dogs and cats. We noted 26 E. menigoseptica, 1 E. miricola, and 59 unspeciated Elizabethkingia isolates from 9 US states (2-22 isolates per state). Elizabethkingia infections in animals might increase risks to humans.

Chryseobacterium indologenes Bacteraemia: A Potential Cause of Early-onset Neonatal Sepsis in a Full-term Baby

Chryseobacterium indologenes is considered as an emerging pathogen known to cause pneumonia, bacteremia, and meningitis in children. It has been reported previously, mainly from the Indian subcontinent, as a rare cause of early-onset neonatal infection, mostly affecting preterm infants. We report the first case in the United Kingdom in which C. indologenes was isolated from the blood culture of a term infant who was clinically suspected of having early-onset neonatal sepsis. Our case had a good outcome, but mortality has been reported in published literature. A positive neonatal blood culture of C. indologenes should not automatically be considered as a contaminant; and a joint discussion between neonatologists and microbiologists should determine the appropriate management and antibiotic regimen. Key Words: Early-onset neonatal sepsis, Bacteremia, Chryseobacterium indologenes, Contaminant, Antibiotics.

Detecting Flavobacterial Fish Pathogens in the Environment via High-Throughput Community Analysis

Diseases caused by the fish pathogens Flavobacterium columnare and Flavobacterium psychrophilum are major contributors of preventable losses in the aquaculture industry. The persistent and difficult-to-control infections caused by these bacteria make timely intervention and prophylactic elimination of pathogen reservoirs important measures to combat these disease-causing agents. In this study, we present two independent assays for detecting these pathogens in a range of environmental samples. Natural water samples were inoculated with F. columnare and F. psychrophilum over 5 orders of magnitude, and pathogen levels were detected using Illumina MiSeq sequencing and droplet digital PCR. Both detection methods accurately identified pathogen-positive samples and showed good agreement in quantifying each pathogen. Additionally, the real-world application of these approaches was demonstrated using environmental samples collected at a rainbow trout (Oncorhynchus mykiss) aquaculture facility. These results show that both methods can serve as useful tools for surveillance efforts in aquaculture facilities, where the early detection of these flavobacterial pathogens may direct preventative measures to reduce disease occurrence. IMPORTANCE Early detection of a deadly disease outbreak in a population can be the difference between mass mortality or mitigated effects. In the present study, we evaluated and compared two molecular techniques for detecting economically impactful aquaculture pathogens. We demonstrate that one of these techniques, 16S rRNA gene sequencing using Illumina MiSeq technology, provides the ability to accurately detect two freshwater fish pathogens, F. columnare and F. psychrophilum, while simultaneously profiling the native microbial community. The second technique, droplet digital PCR, is commonly used for pathogen detection, and the results obtained using the assays we designed with this method served to validate those obtained using the MiSeq method. These two methods offer distinct advantages. The MiSeq method pairs pathogen detection and microbial community profiling to answer immediate and long-term fish health concerns, while the droplet digital PCR method provides fast and highly sensitive detection that is useful for surveillance and rapid clinical responses.

Quantitative PCR for Tenacibaculum dicentrarchi and T. finnmarkense

Numerous Tenacibaculum species, including T. dicentrarchi, T. maritimum and T. finnmarkense, are associated with tenacibaculosis in finfish; however, quantitative identification techniques are limited. Quantitative PCR assays were developed to detect T. dicentrarchi and T. finnmarkense. TaqMan assays using 16S rDNA demonstrated low detection limits (0.07-269 bacteria), suitable amplification efficiencies (>86%) and moderate specificity. However, the amplification of isolates with 100% sequence similarity to T. finnmarkense AY7486TD using both the T. finnmarkense and T. dicentrarchi assays indicates that other genes should be investigated. Both assays may help describe the pathogenesis of tenacibaculosis and may aid management practices for the aquaculture industry.

Comparison of three species of Elizabethkingia genus by whole-genome sequence analysis

Elizabethkingia are found to cause severe neonatal meningitis, nosocomial pneumonia, endocarditis and bacteremia. However, there are few studies on Elizabethkingia genus by comparative genomic analysis. In this study, three species of Elizabethkingia were found: E. meningoseptica, E. anophelis and E. miricola. Resistance genes and associated proteins of seven classes of antibiotics including beta-lactams, aminoglycosides, macrolides, tetracyclines, quinolones, sulfonamides and glycopeptides, as well as multidrug resistance efflux pumps were identified from 20 clinical isolates of Elizabethkingia by whole-genome sequence. Genotype and phenotype displayed a good consistency in beta-lactams, aminoglycosides and glycopeptides, while contradictions exhibited in tetracyclines, quinolones and sulfonamides. Virulence factors and associated genes such as hsp60 (htpB), exopolysaccharide (EPS) (galE/pgi), Mg2+ transport (mgtB/mgtE) and catalase (katA/katG) existed in all clinical and reference strains. The functional analysis of the clusters of orthologous groups indicated that 'metabolism' occupied the largest part in core genome, 'information storage and processing' was the largest group in both accessory genome and unique genome. Abundant mobile elements were identified in E. meningoseptica and E. anophelis. The most significant finding in our study was that a single clone of E. anophelis had been circulating within diversities of departments in a clinical setting for nearly 18 months.

Elizabethkingia anophelis Infection in Infants, Cambodia, 2012-2018

We describe 6 clinical isolates of Elizabethkingia anophelis from a pediatric referral hospital in Cambodia, along with 1 isolate reported from Thailand. Improving diagnostic microbiological methods in resource-limited settings will increase the frequency of reporting for this pathogen. Consensus on therapeutic options is needed, especially for resource-limited settings.

Multiplex PCR for genotyping Flavobacterium columnare

Recent research has identified four distinct genetic groups among isolates of Flavobacterium columnare through multilocus phylogenetic analyses; however, there are no quick methods to determine the genotype of an isolate. The objective of this research was to develop a multiplex PCR to rapidly genotype F. columnare to genetic group. Comparative bacterial genomics was used to identify regions in the genomes unique to each genetic group, and primers were designed to specifically amplify different sized amplicons for each genetic group. The optimized assay was demonstrated to be specific for each genetic group and F. columnare, and no specific amplicons were generated using gDNA from a panel of other Flavobacterium spp. and bacterial fish pathogens. The analytical sensitivity of the assay ranged from 209 to 883 genome equivalents depending on the genetic group. The multiplex PCR was evaluated by genotyping a panel of 22 unknown F. columnare isolates and performing DNA sequencing of the dnaK gene in parallel. The results demonstrated 100% accordance between multiplex PCR results and assignment to genetic group via phylogenetic analysis. The multiplex PCR provides a useful tool for assigning an unknown isolate to genetic group and may be used to determine which genetic groups of F. columnare are circulating and most predominant in different aquaculture industries.

Elizabethkingia in Children: A Comprehensive Review of Symptomatic Cases Reported From 1944 to 2017

Elizabethkingia species often exhibit extensive antibiotic resistance and result in high morbidity and mortality, yet no systematic reviews exist that thoroughly characterize and quantify concerns for infected infants and children. We performed a review of literature and identified an initial 902 articles; 96 articles reporting 283 pediatric cases met our inclusion criteria and were subsequently reviewed. Case reports spanned 28 countries and ranged from 1944 to 2017. Neonatal meningitis remains the most common presentation of this organism in children, along with a range of other clinical manifestations. The majority of reported cases occurred as isolated cases, rather than within outbreaks. Mortality was high but has decreased in recent years, although neurologic sequelae among survivors remains concerning. Child outcomes can be improved through effective prevention measures and early identification and treatment of infected patients.

Elizabethkingia anophelis and Association with Tap Water and Handwashing, Singapore

We report an Elizabethkingia anophelis case cluster associated with contaminated aerators and tap water in a children’s intensive care unit in Singapore in 2017. We demonstrate a likely transmission route for E. anophelis to patients through acquisition of the bacteria on hands of healthcare workers via handwashing.

Determination of Elizabethkingia Diversity by MALDI-TOF Mass Spectrometry and Whole-Genome Sequencing

In a hospital-acquired infection with multidrug-resistant Elizabethkingia, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and 16S rRNA gene analysis identified the pathogen as Elizabethkingia miricola. Whole-genome sequencing, genus-level core genome analysis, and in silico DNA-DNA hybridization of 35 Elizabethkingia strains indicated that the species taxonomy should be further explored.

Evidence for Elizabethkingia anophelis transmission from mother to infant, Hong Kong

Genome sequencing can provide rapid insights on transmission and pathogenesis of emerging pathogens.

Elizabethkingia anophelis, recently discovered from mosquito gut, is an emerging bacterium associated with neonatal meningitis and nosocomial outbreaks. However, its transmission route remains unknown. We use rapid genome sequencing to investigate 3 cases of E. anophelis sepsis involving 2 neonates who had meningitis and 1 neonate’s mother who had chorioamnionitis. Comparative genomics revealed evidence for perinatal vertical transmission from a mother to her neonate; the 2 isolates from these patients, HKU37 and HKU38, shared essentially identical genome sequences. In contrast, the strain from another neonate (HKU36) was genetically divergent, showing only 78.6% genome sequence identity to HKU37 and HKU38, thus excluding a clonal outbreak. Comparison to genomes from mosquito strains revealed potential metabolic adaptations in E. anophelis under different environments. Maternal infection, not mosquitoes, is most likely the source of neonatal E. anophelis infections. Our findings highlight the power of genome sequencing in gaining rapid insights on transmission and pathogenesis of emerging pathogens.

Development of colloidal gold immunochromatographic strips for detection of Riemerella anatipestifer

Riemerella anatipestifer is one of the most important bacterial pathogen of ducks and causes a contagious septicemia. R. anatipestifer infection causes serositis syndromes similar to other bacterial infections in ducks, including infection by Escherichia coli, Salmonella enterica and Pasteurella multocida. Clinically differentiating R. anatipestifer infections from other bacterial pathogen infections is usually difficult. In this study, MAb 1G2F10, a monoclonal antibody against R. anatipestifer GroEL, was used to develop a colloidal gold immunochromatographic strip. Colloidal gold particles were prepared by chemical synthesis to an average diameter of 20 ± 5.26 nm by transmission electron microscope imaging. MAb 1G2F10 was conjugated to colloidal gold particles and the formation of antibody-colloidal gold conjugates was monitored by UV/Vis spectroscopy. Immunochromatographic strips were assembled in regular sequence through different accessories sticked on PVC plate. Strips specifically detected R. anatipestifer within 10 min, but did not detect E. coli, S. enterica and P. multocida. The detection limit for R. anatipestifer was 1 × 10(6) colony forming units, which was 500 times higher than a conventional agglutination test. Accuracy was 100% match to multiplex PCR. Assay stability and reproducibility were excellent after storage at 4°C for 6 months. The immunochromatographic strips prepared in this study offer a specific, sensitive, and rapid detection method for R. anatipestifer, which is of great importance for the prevention and control of R. anatipestifer infections.

Colorimetric Method of Loop-Mediated Isothermal Amplification with the Pre-Addition of Calcein for Detecting Flavobacterium columnare and its Assessment in Tilapia Farms

Flavobacterium columnare, the causative agent of columnaris disease in fish, affects many economically important freshwater fish species. A colorimetric method of loop-mediated isothermal amplification with the pre-addition of calcein (LAMP-calcein) was developed and used to detect the presence of F. columnare in farmed tilapia (Nile Tilapia Oreochromis niloticus and red tilapia [Nile Tilapia × Mozambique Tilapia O. mossambicus]) and rearing water. The detection method, based on a change in color from orange to green, could be performed within 45 min at 63°C. The method was highly specific, as it had no cross-detections with 14 other bacterial species, including other fish pathogens and two Flavobacterium species. The method has a minimum detection limit of 2.2 × 10(2) F. columnare CFU; thus, it is about 10 times more sensitive than conventional PCR. With this method, F. columnare was detected in gonad, gill, and blood samples from apparently healthy tilapia broodstock as well as in samples of fertilized eggs, newly hatched fry, and rearing water. The bacteria isolated from the blood were further characterized biochemically and found to be phenotypically identical to F. columnare. The amplified products from the LAMP-calcein method had 97% homology with the DNA sequence of F. columnare.

A Nephrostomy-associated Urinary Tract Infection Caused by Elizabethkingia meningoseptica

We report a case of nephrostomy-associated urinary tract infection caused by Elizabethkingia meningoseptica that occurred in a patient with retroperitoneal fibrosis. Though conventional identification methods failed to detect the causative organism, it was identified on the basis of the complete sequencing of 16S rRNA. Four weeks of levofloxacin and minocycline administration successfully eradicated the infection. E. meningoseptica rarely causes urinary tract infections, and we believe that this is the first such case in which the isolate was genetically confirmed. The accurate identification of the organism is necessary for the provision of appropriate treatment and to obtain a better understanding of its epidemiology and pathogenicity.

Immunohistochemical diagnosis of tenacibaculosis in paraffin-embedded tissues of Senegalese sole Solea senegalensis Kaup, 1858

A sensitive and specific immunohistochemical technique was developed to improve the diagnosis of tenacibaculosis and to better understand its pathogenesis. Senegalese sole Solea senegalensis Kaup, 1858 were inoculated subcutaneously with a bacterial suspension of Tenacibaculum maritimum, and samples were taken at different hours post-inoculation. Sections from different organs were used as positive controls. In addition, a total of 128 field samples from different organs collected from tenacibaculosis outbreaks were used. Tenacibaculum maritimum antigens were detected in several organs of experimentally infected Senegalese sole and in at least one of the tissues from fish suffering from natural tenacibaculosis previously confirmed by culture and PCR-based methods. In fish collected during outbreaks, a strong positive reaction was detected in ulcerative skin areas. Moreover, bacterial antigen was identified inside scale pockets and in sites of the skin with mild lesion. In kidney and spleen, evident immunostaining of bacterial antigen was detected in both naturally and experimentally infected fish. Besides, the presence of T. maritimum in the intestinal tract without associated histological changes suggests that this organ may act as a reservoir for T. maritimum. The results of this study confirm the usefulness of IHC for the diagnosis of tenacibaculosis in paraffin-embedded tissues.

Elizabethkingia meningoseptica as an unusual pathogen causing healthcare-associated bacteriuria

Elizabethkingia meningoseptica is recovered from urine samples in very unusual cases, although the clinical significance of its detection remains unclear. Four cases of E. meningoseptica bacteriuria were analyzed, and E. meningoseptica was found to be the causative agent of healthcare-associated bacteriuria, including urinary tract infections, asymptomatic bacteriuria and transient bacteriuria, primarily in elderly patients with diabetes. Although E. meningoseptica cultured from urine was found to be resistant to most antimicrobial agents, bacteriuria caused by E. meningoseptica resolved in all four cases. However, instances of death have also been previously reported.

Columnaris disease in fish: a review with emphasis on bacterium-host interactions

Flavobacterium columnare (F. columnare) is the causative agent of columnaris disease. This bacterium affects both cultured and wild freshwater fish including many susceptible commercially important fish species. F. columnare infections may result in skin lesions, fin erosion and gill necrosis, with a high degree of mortality, leading to severe economic losses. Especially in the last decade, various research groups have performed studies aimed at elucidating the pathogenesis of columnaris disease, leading to significant progress in defining the complex interactions between the organism and its host. Despite these efforts, the pathogenesis of columnaris disease hitherto largely remains unclear, compromising the further development of efficient curative and preventive measures to combat this disease. Besides elaborating on the agent and the disease it causes, this review aims to summarize these pathogenesis data emphasizing the areas meriting further investigation.

Fluorescent In Situ hybridization: a new tool for the direct identification and detection of F. psychrophilum

F. psychrophilum is the causative agent of Bacterial Cold Water Disease (BCW) and Rainbow Trout Fry Syndrome (RTFS). To date, diagnosis relies mainly on direct microscopy or cultural methods. Direct microscopy is fast but not very reliable, whereas cultural methods are reliable but time-consuming and labor-intensive. So far fluorescent in situ hybridization (FISH) has not been used in the diagnosis of flavobacteriosis but it has the potential to rapidly and specifically detect F. psychrophilum in infected tissues. Outbreaks in fish farms, caused by pathogenic strains of Flavobacterium species, are increasingly frequent and there is a need for reliable and cost-effective techniques to rapidly diagnose flavobacterioses. This study is aimed at developing a FISH that could be used for the diagnosis of F. psychrophilum infections in fish. We constructed a generic probe for the genus Flavobacterium (“Pan-Flavo”) and two specific probes targeting F. psychrophilum based on 16S rRNA gene sequences. We tested their specificity and sensitivity on pure cultures of different Flavobacterium and other aquatic bacterial species. After assessing their sensitivity and specificity, we established their limit of detection and tested the probes on infected fresh tissues (spleen and skin) and on paraffin-embedded tissues. The results showed high sensitivity and specificity of the probes (100% and 91% for the Pan-Flavo probe and 100% and 97% for the F. psychrophilum probe, respectively). FISH was able to detect F. psychrophilum in infected fish tissues, thus the findings from this study indicate this technique is suitable as a fast and reliable method for the detection of Flavobacterium spp. and F. psychrophilum.

Development of a quantitative real-time PCR for the detection of Tenacibaculum maritimum and its application to field samples

The development and the application of a quantitative real-time PCR for the detection of Tenacibaculum maritimum are described. A set of primers and probe was designed to amplify a 155-bp fragment specific to the T. maritimum 16S rRNA gene. The test was shown to be very sensitive, able to detect as little as 4.8 DNA copies number μL(-1) . In addition, the assay was found to have a high degree of repeatability and reproducibility, with a linear dynamic range (R(2)  = 0.999) extending over 6 log(10) dilutions and a high efficiency (100%). The assay was applied to DNA samples extracted from 48 formalin-fixed paraffin-embedded (FFPE) Atlantic salmon, Salmo salar, gill tissues showing varying degrees of gill pathology (scored 0-3) and from 26 jellyfish samples belonging to the species Phialella quadrata and Muggiaea atlantica. For each sample, the bacterial load was normalised against the level of the salmonid elongation factor alpha 1 (ELF) detected by a second real-time PCR using previously published primers and probe. Tenacibaculum maritimum DNA was detected in 89% of the blocks with no signs of gill disease as well as in 95% of the blocks with mild-to-severe gill pathology. Association between bacterial load and gill pathology severity was investigated. T. maritimum DNA was detected at low level in four of the 26 jellyfish tested.

Validation of diagnostic assays to screen broodstock for Flavobacterium psychrophilum infections

It is hypothesized that the frequency of bacterial coldwater disease outbreaks can be reduced through the detection of the aetiologic agent, Flavobacterium psychrophilum, in broodstock followed by culling of eggs from heavily infected broodstock. Before a culling programme can be instituted, however, it is necessary to determine the sensitivity and specificity of existing assays for the detection of F. psychrophilum. In this study, tissue and ovarian fluid samples were collected from 224 fish at five hatcheries and screened using an enzyme-linked immunosorbent assay (ELISA), a membrane-filtration fluorescent antibody test (MF-FAT), bacteriological culture and nested PCR. Latent class analysis was used to estimate sensitivity and specificity of kidney culture, kidney ELISA, nested PCR and MF-FAT. Analytical sensitivity of the ELISA varied but was greatest when bacteria were cultured under iron-limiting conditions. Diagnostic sensitivity estimates ranged from 0.02 (kidney culture) to 0.97 (kidney ELISA). Specificity estimates ranged from 0.02 (MF-FAT) to 0.98 (kidney ELISA). In a separate challenge experiment, the ELISA confirmed the presence of F. psychrophilum in sub-clinically infected fish. Results from this study demonstrate that the ELISA is an appropriate tool to screen broodstock and provides an indication of infection severity, which is crucial for implementation of a screening/culling programme.

[Relevance and diagnostics of selected bacterial pathogens of poultry]

This paper provides an overview of diseases caused by Bordetella avium, Gallibacterium anatis, Ornithobacterium rhinotracheale, Riemerella anatipestifer and Enterococcus cecorum in poultry flocks. These bacterial species are almost exclusively found in birds. Their identification with biochemical methods is described and alternative molecular biological methods are discussed.

Misidentification of Brucella melitensis as Bergeyella zoohelcum by MicroScan WalkAway®: a case report

OBJECTIVE

To describe the misidentification of Brucella melitensis as Bergeyella zoohelcum by MicroScan WalkAway®, a commonly used bacterial identification system.

CLINICAL PRESENTATION AND INTERVENTION

A 35-year-old man was admitted to the Intensive Care Unit with sepsis syndrome. Three sets of aerobic blood culture samples were positive after 48 h of incubation. The isolated organism was identified as B. zoohelcum using the MicroScan WalkAway (Siemens Healthcare Diagnostics Inc., West Sacramento, Calif., USA). However, due to the rareness of the pathogen, the isolate was reidentified as B. melitensis with Vitek® 2 system and later 16S ribosomal sequence analysis confirmed the isolate as B. melitensis having 100% match.

CONCLUSION

This case showed that Brucella can be misidentified using MicroScan WalkAway. Countries where brucellosis is endemic need to be careful while using such automated identification systems in order not to miss the diagnosis of Brucella.

Rapid detection and identification of viral and bacterial fish pathogens using a DNA array-based multiplex assay

Fish diseases can be caused by a variety of diverse organisms, including bacteria, fungi, viruses and protozoa, and pose a universal threat to the ornamental fish industry and aquaculture. The lack of rapid, accurate and reliable means by which fish pathogens can be detected and identified has been one of the main limitations in fish pathogen diagnosis and fish disease management and has consequently stimulated the search for alternative diagnostic techniques. Here, we describe a method based on multiplex and broad-range PCR amplification combined with DNA array hybridization for the simultaneous detection and identification of all cyprinid herpesviruses (CyHV-1, CyHV-2 and CyHV-3) and some of the most important fish pathogenic Flavobacterium species, including F. branchiophilum, F. columnare and F. psychrophilum. For virus identification, the DNA polymerase and helicase genes were targeted. For bacterial identification, the ribosomal RNA gene was used. The developed methodology permitted 100% specificity for the identification of the target species. Detection sensitivity was equivalent to 10 viral genomes or less than a picogram of bacterial DNA. The utility and power of the array for sensitive pathogen detection and identification in complex samples such as infected tissue is demonstrated in this study.

Septic shock, pneumonia, and soft tissue infection due to Myroides odoratimimus: report of a case and review of Myroides infections

The genus Myroides comprises aerobic, yellow-pigmented, non-motile, non-fermenting gram-negative rods formerly classified as Flavobacterium odoratum. Members of the genus are widely distributed in the environment, especially in water, and usually behave as low-grade opportunistic pathogens, having been found to cause urinary tract infection, endocarditis, ventriculitis, and cutaneous infections in severely immunocompromised patients. We report a case of soft tissue infection, septic shock, and pneumonia due to M. odoratimimus in an immunocompetent male. To our knowledge, this is the first description of life-threatening infection caused by this organism in an immunocompetent host. We have also reviewed the medical literature on the genus Myroides.

Development and evaluation of a loop-mediated isothermal amplification assay for rapid and simple detection of Flavobacterium psychrophilum

Flavobacterium psychrophilum is the causative agent of bacterial cold-water disease and rainbow trout fry syndrome of salmonids. The pathogen has been reported from all regions in the world involved in salmonid aquaculture, but also from natural fresh-water environments. We established a quantitative loop-mediated isothermal amplification of DNA (LAMP) method to estimate quantities of F. psychrophilum. LAMP primers were designed based on the sequence of the DNA topoisomerase IV subunit B gene, parE, of F. psychrophilum. parE LAMP exhibited a high specificity for the parE gene of F. psychrophilum but not for other related species. parE LAMP detected the gene in a wide range of concentrations from 2.0 x 10(1) to 2.0 x 10(9) copies/reaction within 70 min and revealed a good correlation between threshold times and gene copy number.

Chryseobacterium indologenes Bacteremia in a Bone Marrow Transplant Recipient with Chronic Graft-versus-Host Disease

We describe a case of Chryseobacterium indologenes bacteremia in a leukemia patient with chronic graft-versus-host disease (GVHD) 6 months after allogeneic bone marrow transplantation. Blood cultures from a vein and via Hickman catheter grew C. indologenes. The patient was successfully treated with piperacillin/tazobactam and the infection did not recur. Our case indicates that C. indologenes infection can occur in patients with GVHD after allogeneic BMT and might be treated with a single agent, piperacillin/tazobactam without the removal of intravascular catheter.

A quantitative enzyme-linked immunosorbent assay and filtration-based fluorescent antibody test as potential tools to screen broodstock for infection with Flavobacterium psychrophilum

There is strong evidence that Flavobacterium psychrophilum, the etiologic agent of coldwater disease, is transmitted vertically; it has been hypothesized that disease management at hatchery facilities can be improved through broodstock screening and implementation of culling programs. This paper describes the development of two assays used to screen broodstock tissues (kidney and ovarian fluid) for the presence of F. psychrophilum. Four monoclonal antibodies (MAbs) were generated against outer membrane preparations of F. psychrophilum strain CSF (Clear Springs Foods) 259-93. Of these, MAb FL43 was selected for assay development; this MAb reacted with 67 isolates of F. psychrophilum but exhibited no reaction with two strains of F. columnare or single strains of F. pectinovorum, F. aquatile, F. branchiophilum, and F. saccharophilum. An enzyme-linked immunosorbent assay (ELISA) was developed using MAb FL43 as the capture antibody and MAb FL43 conjugated to horseradish peroxidase (enzyme number 1.11.1.7; IUBMB 1992) as the secondary detection antibody. The ELISA had a lower F. psychrophilum detection boundary of approximately 1.6 X 10(3) colony-forming units (CFU)/mL in kidney tissue homogenates spiked with known bacterial concentrations. Asymptomatic broodstock of coho salmon Oncorhynchus kisutch (n = 50 fish) were sampled, and 100% tested positive for infection by ELISA analysis of kidney tissue; bacterial load was estimated at 2.0 x 10(3) to 9.4 x 10(3) CFU/mL. Ovarian fluid was also collected from these same coho salmon as well as from broodstock of rainbow trout O. mykiss; however, the ELISA proved to be unsuitable for use with ovarian fluid. A filtration-based fluorescent antibody test (FAT) was subsequently developed by conjugating MAb FL43 to Alexa Fluor 488. This FAT was able to detect F. psychrophilum in 74% of ovarian fluid samples collected from coho salmon and 42% of ovarian fluid samples from rainbow trout. Interestingly, yellow-pigmented bacteria were isolated on culture plates from 100% of kidney and ovarian fluid samples. All yellow-pigmented colonies were tested by polymerase chain reaction, and 100% of the coho salmon and rainbow trout were confirmed positive for infection with F. psychrophilum.

Lumboperitonial shunt infection due to Chryseobacterium indologenes

Chryseobacterium indologenes central nervous system infection has not been reported. We present a case of lumboperitoneal shunt infection caused by C. indologenes successfully treated with trimethoprim-sulfamethoxazole and rifampin in a pediatric patient. Forty-three additional cases of C. indologenes non-central nervous system infections reported in the English medical literature were reviewed. Risk factors for C. indologenes infections include underlying medical illnesses, underlying immunocompromising conditions and presence of indwelling intravascular devices.

Chryseobacterium meningosepticum Infection and Cardiac Tamponade in a Long-Term Hemodialysis Patient

Chryseobacterium meningosepticum is a lactose-nonfermenting gram-negative bacilli ubiquitously found in the natural and hospital environment. Clinical infection caused by C. meningosepticum is very rare among healthy adults. We present the case of a patient with end-stage renal disease who developed purulent pericarditis with C. meningosepticum infection, which rapidly evolved into cardiac tamponade and death. To our knowledge, this is the first case in which C. meningosepticum caused fatal purulent pericarditis in a hemodialysis patient.

Tenacibaculosis infection in marine fish caused by Tenacibaculum maritimum: a review

Tenacibaculum maritimum is the aetiological agent of an ulcerative disease known as tenacibaculosis, which affects a large number of marine fish species in the world and is of considerable economic significance to aquaculture producers. Problems associated with epizootics include high mortality rates, increased susceptibility to other pathogens, high labour costs of treatment and enormous expenditures on chemotherapy. In the present article we review current knowledge on this bacterial pathogen, focusing on important aspects such as the phenotypic, serologic and genetic characterization of the bacterium, its geographical distribution and the host species affected. The epizootiology of the disease, the routes of transmission and the putative reservoirs of T. maritimum are also discussed. We include a summary of molecular diagnostic procedures, the current status of prevention and control strategies, the main virulence mechanisms of the pathogen, and we attempt to highlight fruitful areas for continued research.

Sensitive and rapid detection of Flavobacterium columnare in channel catfish Ictalurus punctatus by a loop-mediated isothermal amplification method

AIMS

To evaluate the loop-mediated isothermal amplification method (LAMP) for rapid detection of Flavobacterium columnare and determine the suitability of LAMP for rapid diagnosis of columnaris infection in channel catfish, Ictalurus punctatus.

METHODS AND RESULTS

A set of four primers, two outer and two inner, were designed specifically to recognize 16S ribosomal RNA gene of this pathogen. Bacterial genomic DNA templates were prepared by hot lysis in a lysis buffer. Amplification of the specific gene segments was carried out at 65 degrees C for 1 h. The amplified gene products were analysed by agarose gel electrophoresis and detected by staining gels with ethidium bromide. A PCR assay was also included in this study. Our results demonstrate that the ladder-like pattern of bands from 204 bp specific to the Fl. columnare 16S ribosomal RNA gene was amplified. The detection limit of the LAMP assay was comparable to that of PCR in prepared genomic DNA reactions. In addition, this optimized LAMP assay was able to detect the Fl. columnare 16S ribosomal RNA gene in experimentally infected channel catfish.

CONCLUSIONS

The LAMP assay for Fl. columnare detection in channel catfish was established.

SIGNIFICANCE AND IMPACT OF THE STUDY

Because LAMP assay is a rapid, sensitive, specific, simple and cost-effective assay for Fl. columnare detection in channel catfish, it is useful for rapid diagnosis of Fl. columnare in fish hatcheries and the field.

[First documented case of Chryseobacterium meningosepticum meningitis in Central African Republic]

Chryseobacterium meningosepdcum is a rare but well-known causative agent of bacterial meningitis and can be the source of epidemic outbreak in neonatal facilities. It has rarely been documented in Africa. The purpose of this report is to describe the first case of C. meningosepticum meningitis in Central African Republic. The case that remained isolated occurred after dystocic delivery with resuscitation in a neonatal unit. Despite intensive care and appropriate antibiotic treatment, the newborn died on day 19. Identification of this rare cause of meningitis underlines the important role of the bacteriologic laboratory in managing bacterial meningitis in Africa. The strain of C. meningosepticum involved in this case was resistant to the main antibiotics used for first-intention treatment of neonatal bacterial meningitis, i.e., third-generation cefalosporins, chioramphenicol, and aminosides. This case also underlines the importance of familiarizing the medical staff with the dangers of nosocomial meningitis and reinforcing hospital hygiene measures.

Immunofluorescent test for simultaneous detection of Edwardsiella ictaluri and Flavobacterium columnare

Enteric septicemia of catfish (ESC) and columnaris disease are 2 bacterial diseases significantly affecting the aquaculture industry, and thus rapid diagnosis of disease is imperative for making judicious management decisions. A rapid indirect fluorescent antibody (IFA) test with antibody conjugated fluorochromes having 2 different spectral properties (Alexa Fluor 488-emitting green fluorescence, and Alexa Fluor 594-emitting red fluorescence) was compared with bacteriological culture (accepted standard) for simultaneous detection of Edwardsiella ictaluri (EI) and Flavobacterium columnare (FC) in 3 groups of experimentally infected channel catfish (Ictalurus punctatus Rafinesque), and a fourth group that acquired an aquarium-infection with F. columnare. A total of 303 samples (derived from kidney, brain and nares) from 101 fish were concurrently examined by both tests. Fish in the 3 experimentally infected groups (I to III) were culture positive for the bacteria with which they were infected, and fish in Group IV, (the spontaneously infected fish) revealed F. columnare only. The IFA test compared favorably in sensitivity (EI= 80.7 %; FC = 87.2%) and specificity (EI = 83.9%; FC = 88.9%) with the standard bacteriological culture. The positive predictive value (EI = 96.2% Group I, 90.8% Group II, 93.7% Groups I and II combined; FC = 95.2% Group II, 95.3% Groups II, III and IV combined) was high, while the negative predictive value (EI = 66.7% Group I, 31.3% Group II, 59.5% Groups I and II combined; FC = 73.7% Group II, 72.7% Groups II, III and IV combined) was relatively low. The IFA test will serve as an efficient tool for rapid simultaneous detection of E. ictaluri and F. columnare in outbreaks of disease.

Transmission and detection of Flavobacterium columnare in channel catfish Ictalurus punctatus

A specific and rapid PCR detection method for Flavobacterium columnare based on the 16S-23S rDNA intergenic spacer region (ISR) of the ribosomal RNA operon has been developed. The ISR of 30 F. columnare strains and other Flavobacterium species was amplified using universal primers and sequenced. Once F. columnare specific sequences within the ISR were recognized, specific PCR primers were designed against them (FCISRFL and FCISRR1). The primers were sensitive and able to detect as low as 7 colony forming units from pure culture by PCR. The new PCR detection method was applied to experimentally infected channel catfish. Two different experiments in which channel catfish fingerlings were infected by intramuscular injection or by immersion bath showed the advantage of the PCR method over standard culture techniques. F. columnare was detected by PCR in both tank water and catfish tissue samples with a higher frequency and in less time than standard microbiological methods. Furthermore, PCR detection confirmed that F. columnare can be transmitted horizontally indirectly through the water column without fish-to-fish contact. The newly developed PCR detection method for F. columnare was more sensitive and rapid than standard culture on bacteriological media for detection of F. columnare in channel catfish tissues and in tank water.

Diagnosis of Ornithobacterium rhinotracheale infection in chickens by ELISA

Specific Ornithobacterium rhinotracheale (ORT) antibodies were determined in serum samples of 24 clinically infected broiler flocks of different ages (1-42 d) and 11 broiler-breeding flocks (at ages between 26-56 w) by ELISA. Two commercially available kits were separately assessed. The BioCheck ELISA kit was used for testing 363 serum samples representing 12 broiler flocks, where 74 samples (20.3 %) were found to be positive and 49 (13.5 %) were suspected. The IDEXX ELISA kit was used for testing 148 serum samples representing different 12 broiler flocks, where 115 samples (77.7 %) were positive. Testing of additional 70 serum samples from 5 broiler- breeder flocks, associated with drop in egg production (1-4.5 %) at different ages, by BioCheck ELISA kit revealed that 78.5 % of the samples were positive and 21.4% were suspected. On the other hand, 338 serum samples representing 6 broiler-breeder flocks, associated also with egg drop, showed a 84.6 % rate of positive reaction, when tested by IDEXX ELISA kit. Positive serology correlated well with the clinical manifestations and isolation of the organism, which substantiates the reliability of the used kits in diagnosis of the disease.