Chromosome-encoded beta-lactamases TUS-1 and MUS-1 from Myroides odoratus and Myroides odoratimimus (formerly Flavobacterium odoratum), new members of the lineage of molecular subclass B1 metalloenzymes

Molecular characterization of the multi-drug resistant Myroides odoratimimus isolates: a whole genome sequence-based study to confirm carbapenem resistance

The bacteria belonging to the Myroides genus are opportunistic pathogens causing community or hospital-acquired infections that result in treatment failure due to antibiotic resistance. This study aimed to investigate molecular mechanisms of antibiotic resistance, clonal relatedness, and the biofilm forming capacity of the 51 multi-drug resistant Myroides odoratimimus. All isolates were screened for blaKPC, blaOXA, blaVIM, blaIMP, blaMUS, blaTUS, blaNDM, and blaB genes by using PCR amplification. Whole genome sequencing (WGS) was applied on three randomly selected isolates for further investigation of antibiotic resistance mechanisms. Clonal relatedness was analyzed by Pulsed-field gel electrophoresis (PFGE) and the microtiter plate method was used to demonstrate biofilm formation. All isolates were positive for biofilm formation. PCR analysis resulted in a positive for only the blaMUS-1 gene. WGS identified blaMUS-1, erm(F), ere(D), tet(X), and sul2 genes in all strains tested. Moreover, the genomic analyses of three strains revealed that genomes contained a large number of virulence factors (VFs). PFGE yielded a clustering rate of 96%. High clonal relatedness, biofilm formation, and multi-drug resistance properties may lead to the predominance of these opportunistic pathogens in hospital environments and make them cause nosocomial infections.

Secondary bacterial corneal infection caused by Myroides species in primary fungal keratitis

A middle-aged male patient presented with a central corneal perforation in a deep stromal infiltrate in his left eye. An emergency therapeutic penetrating keratoplasty was performed. Microbiological evaluation of the corneal scraping specimen revealed septate fungal filaments on stains. However, culture reports after 24 hours from the scraping sample and the excised half corneal button showed growth of gram-negative bacilli. This pathogen was identified as an aerobic, non-fermentative, gram-negative, bacillus by conventional microbiology and confirmed as Myroides species by the VITEK 2 Compact system (bioMérieux, Marcy l'Etoile, France). Susceptibility to chloramphenicol was noted based on which the patient was treated with topical chloramphenicol 0.5%. No recurrence of the infection was noted. This is the first reported case of corneal infection with the Myroides species of bacteria which, heretofore, have been known to cause endocarditis and urinary tract infections.

Strategies to Name Metallo-β-Lactamases and Number Their Amino Acid Residues

Metallo-β-lactamases (MBLs), also known as class B β-lactamases (BBLs), are Zn(II)-containing enzymes able to inactivate a broad range of β-lactams, the most commonly used antibiotics, including life-saving carbapenems. They have been known for about six decades, yet they have only gained much attention as a clinical problem for about three decades. The naming conventions of these enzymes have changed over time and followed various strategies, sometimes leading to confusion. We are summarizing the naming strategies of the currently known MBLs. These enzymes are quite diverse on the amino acid sequence level but structurally similar. Problems trying to describe conserved residues, such as Zn(II) ligands and other catalytically important residues, which have different numbers in different sequences, have led to the establishment of a standard numbering scheme for BBLs. While well intended, the standard numbering scheme is not trivial and has not been applied consistently. We revisit this standard numbering scheme and suggest some strategies for how its implementation could be made more accessible to researchers. Standard numbering facilitates the comparison of different enzymes as well as their interaction with novel antibiotics and BBL inhibitors.

Myroides odoratimimus: a New Threat with Persistent Infections, Multidrug Resistance, and the Potential for Hospital Outbreaks

Myroides species have recently been reported more frequently in outbreaks in clinics and intensive care units (ICUs). In this study, we aimed to investigate the epidemic potential, antibiotic resistance profile, and risk factors of M. odoratimimus isolates that are increasingly being isolated from the ICUs of our hospital. Data from patients whose Myroides spp. were isolated from their clinical specimens over a 5-year period (September 2016 to January 2022) were retrospectively analyzed. Bacterial identification was performed using a matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). The presence of antibiotic resistance genes was analyzed using polymerase chain reaction (PCR). Possible clonal associations between isolates were investigated using enterobacterial repetitive intergenic consensus (ERIC)-PCR. As a result, 66 isolates were identified as M. odoratimimus and one isolate was identified as M. odoratus. The blaMUS resistance gene was detected in all M. odoratimimus isolates, whereas sul2 was detected in ten isolates and tetX was detected in 11 isolates. No other resistance genes, such as blaTUS, were detected. Additionally, two different clonal association patterns were discovered in the 24 selected isolates through the ERIC-PCR method. The increase in the immunosuppressive patient population indicate the possibility of encountering this agent and other opportunistic pathogens more frequently in the future.

Paenimyroides aestuarii gen. nov. sp. nov., a novel bacterium isolated from sediment in the Pearl River Estuary and reclassification of five Flavobacterium and four Myroides species

An aerobic, Gram-negative, non-motile, yellow-to-orange pigmented and round bacterium, designated strain SCSIO 72103T, was isolated from sediment collected in the Pearl River Estuary, Guangdong Province, PR China and subjected to a polyphasic taxonomic study. Growth occurred at 20-37 °C (optimum, 28 °C), pH 6-8 (optimum, pH 7) and with 1-5.5% NaCl (optimum, 1-3 %). Comparative 16S rRNA gene analysis indicated that strain SCSIO 72103T had the highest similarities to Flavobacterium baculatum SNL9T (94.7 %) and Myroides aquimaris SW105T (94.2 %). Phylogenetic analysis based 16S rRNA gene sequences showed that strain SCSIO 72103T formed a single clade with M. aquimaris SW105T. Strain SCSIO 72103T contained iso-C15 : 0 as the major fatty acid and the predominant respiratory quinone was menaquinone MK-6. These characteristics are consistent with those of F. baculatum SNL9T and M. aquimaris SW105T. Phosphatidylethanolamine, most notably, unidentified aminolipid and unidentified aminophospholipid were major polar lipids. Strain SCSIO 72103T had a single circular chromosome of 2.96 Mb with a DNA G+C content of 35.1 mol%. The average nucleotide identity, average amino acid identity (AAI) and digital DNA-DNA hybridization values showed that the pairwise similarities between SCSIO 72103T and the type strains of F. baculatum SNL9T and M. aquimaris SW105T were 78.5-80.5 %, 79.0-81.4 % and 22.7-22.8 %, respectively. The AAI values between species in this clade and the type species of Flavobacterium and Myroides were below the 65 % threshold, indicating that these species belong to a novel genus. On the basis of phylogenetic, physiological and chemotaxonomic characteristics, strain SCSIO 72103T represents a new species of a novel genus, for which the name Paenimyroides aestuarii gen. nov. sp. nov. is proposed. The type strain is SCSIO 72103T (=KCTC 92043T=MCCC 1K06659T). It is also proposed that nine known species in the genera Flavobacterium and Myroides are reclassified as Paenimyroides species.

Case Report of Myroides odoratimimus Cellulitis in Chronic Venous Stasis Dermatitis With Literature Review

Myroides spp.-induced cutaneous infections are rare, with only 17 reported cases in the literature. Myroides spp. behave like low-grade opportunistic pathogens, with symptomatic infections observed typically in severely immunocompromised patients and seldom in immunocompetent patients. In this paper, we present an immunocompetent 61-year old male with a past medical history of hypertension, hyperlipidemia, morbid obesity, and patient-reported peripheral neuropathy who presented to the transitional care clinic with bilateral lower extremity swelling and hemosiderin-pigmented dry wounds consistent with diagnosis of chronic venous stasis dermatitis with resolved secondary Myroides odoratimimus infection. Further literature review about Myroides spp. and its resistance mechanism, antibiotic susceptibility, and biofilm production are also included in this paper.

Antibacterial and Antibiofilm Activities of Ceragenins Alone and in Combination with Levofloxacin Against Multidrug Resistant Myroides spp. Clinical Isolates from Patients with Urinary Tract Infections

Myroides spp. are rare opportunistic pathogens, but they can be life-threatening because of their multidrug-resistant drug properties and their potential to cause outbreaks, especially in immunosuppressed patients. In this study, 33 isolates isolated from intensive care patients with urinary tract infections were examined for drug susceptibility. All isolates except three proved to be resistant to the tested conventional antibiotics. The effects of ceragenins, a class of compounds developed to mimic endogenous antimicrobial peptides, were evaluated against these organisms. The MIC values of nine ceragenins were determined, and the most effective ceragenins were CSA-131 and CSA-138. Three isolates that were susceptible to levofloxacin and two isolates resistant to all antibiotics underwent 16 s rDNA analysis, and whereas resistant isolates were identified as M. odoratus, susceptible isolates were identified as M. odoratimimus. CSA-131 and CSA-138 showed rapid antimicrobial effects observed in time-kill analyses. Combinations of ceragenins and levofloxacin caused a significant increase in antimicrobial and antibiofilm activities against M. odoratimimus isolates. In this study, Myroides spp. were found to be multidrug-resistant and have biofilm forming capacity, and ceragenins CSA-131 and CSA-138 were found to be especially effective on both planktonic and biofilm forms of Myroides spp.

An Increasing Threat in Intensive Care Units, Evaluation of Multi-Drug-Resistant Myroides spp. Infections and Risk Factors

BACKGROUND

Myroides species are gram-negative bacilli that are commonly found in soil and water, acting as low-level opportunistic pathogens and causing a variety of infections.

AIM

The purpose of this study is to assess the risk factors for multidrug-resistant Myroides infections, their association with comorbid illnesses, patient care, and their susceptibility to antibiotics.

METHODS

This retrospective analytical study was conducted in Istanbul Başakşehir Çam and Sakura City Hospital by including patients with Myroides spp isolation in their culture samples. The total hospitalization days, first isolation days, and 30-day mortality values of the patients were analysed statistically, and the significance level was accepted as p < 0.05.

RESULTS

Myroides spp. were isolated from 228 patients' 437 culture samples. Of these cases, 210 (92.1%) were classified as having asymptomatic bacteriuria, and 18 (7.9%) as having an infection caused by Myroides spp. 174 (76.3%) of these patients were followed up in the intensive care unit, and the total hospitalization days (median = 24.50) and the first isolation day (median = 9.50) of infected patients were shorter than colonized patients (p = 0.023, p = 0.030), no difference was found between 30-day mortality (p = 0.312).

CONCLUSIONS

It was observed that Myroides infections could be seen more frequently in patients who were hospitalized for a long time, used broad-spectrum antimicrobials, had invasive procedures, and had co-factors such as diabetes and cerebrovascular disease. In addition, it was observed that the resistance rates of M. odoratus strains were higher than M. odoratimimus strains and the use of quinolone antimicrobials in the treatment of patients with M. odoratimimus infection provided more cure.

Intracranial Myroides odoratimimus Infection After EVD Successfully Treated with Intravenous Plus Intraventricular Tigecycline: A Case Report

Intracranial infections are the most serious and common postoperative complications with significant mortality and morbidity. Myroides odoratimimus (M. odoratimimus), a Gram-negative environmental species and an opportunistic microorganism, predominantly infects immunocompromised individuals. Limited clinical experiences and documented multidrug resistance have resulted in a scarcity of data on the treatment of M. odoratimimus infections. As far as we know, this is the first reported case of an intracranial M. odoratimimus infection with external ventricular drains (EVD) that was effectively treated with a combination of intravenous and intraventricular tigecycline in an immunocompetent adult host.

Characterization and Identification of a novel chromosome-encoded metallo-β-lactamase WUS-1 in Myroides albus P34

In this study, we identified and characterized a novel chromosomally-encoded class B metallo-β-lactamase (MBL) gene designated bla WUS-1 in a carbapenem-resistant isolate Myroides albus P34 isolated from sewage discharged from an animal farm. Comparative analysis of the deduced amino acid sequence revealed that WUS-1 shares the highest amino acid similarities with the function-characterized MBLs MUS-1 (AAN63647.1; 70.73%) and TUS-1 (AAN63648.1; 70.32%). The recombinant carrying bla WUS-1 exhibited increased MICs levels against a number of β-lactam antimicrobials such as carbenicillin, ampicillin and imipenem, and β-lactamase inhibitors (clavulanic acid and tazobactam). The metallo-β-lactamase WUS-1 could also hydrolyze these antimicrobials and the hydrolytic activities could be inhibited by EDTA. Genetic context analysis of bla WUS-1 revealed that no mobile genetic element was found in its surrounding region. The plasmid pMA84474 of Myroides albus P34 harbored 6 resistance genes (bla OXA-347, aadS, bla MYO-1, ereD, sul2 and ermF) within an approximately 17 kb multidrug resistance (MDR) region. These genes, however, were all related to mobile genetic elements.

Extensively Drug-Resistant Myroides odoratus in Critically Ill Patients: A Case Series and Literature Review

The bacterial genus Myroides, like other members of the Flavobacteriaceae family, consists of aerobic, non-motile, Gram-negative bacilli. Myroides spp. is considered predominantly opportunistic pathogens as, historically, most documented infections have been in immunocompromised individuals. Along with advancements in molecular assay testing, there are growing reports of clinically relevant Myroides spp. infections in immunocompetent individuals. These organisms display broad antimicrobial resistance, and while research into their mechanisms of resistance is progressing, genetic testing has revealed metallo-β-lactamases present in their genome. The sporadic identification of Myroides spp. and ongoing clarification of resistance patterns make empiric treatment difficult. This report documents two cases of extensively drug-resistant Myroides odoratus isolated from critically ill but otherwise immunocompetent patients followed by a review of available literature on Myroides spp. antibiotic sensitivities. Our findings indicate that minocycline and moxifloxacin have the highest documented in vitro activity against Myroides spp.

A pan-resistant Myroides odoratimimus catheter-related bacteremia in a COVID-19 patient and review of the literature

Myroides spp. are opportunistic environmental Gram-negative bacteria. These affect mostly immunocompromised hosts and generally lead to soft tissue, and urinary tract infections. Bacteremia most commonly develop secondary to soft tissue or catheter related infections and may lead rarely to mortality. Myroides spp. are generally suscetible to fluoroquinolones, piperacillin/tazobactam, trimethoprim/sulfamethoxazole, carbapenems or tetracyclines however, pan-resistant isolates and multiple resistance genes have been reported in clinical isolates of Myroides spp. We report a pan-resistant Myroides odoratimimus bacteremia in a patient with severe COVID-19 ending with fatality and in this context a review of reported Myroides bacteremias are also described. In this study, a 64-year old male patient with history of coronary artery bypass was admitted to ICU with severe COVID-19 pneumonia accompanied by pneumomediastinum and pneumopericardium. Continous renal replacement therapy and extracorporeal membraneous-oxygenation were initiated due to acute renal failure and persistent hypercarbia/hypoxia, respectively. Within four weeks of hospitalization various episodes of bacteremia developed and multiple antibiotics were used. On the 5th week of follow-up, acute phase reactants increased and empirical broad spectrum antibiotics were initiated. Blood culture revealed Gram-negative rods. The patient became hypotensive and despite maximum medical care he was lost due to cardiac arrest. M. odoratimimus was identified by MALDI-TOF and the bacterium was pan-resistant. According to Center for Genomic Epidemiology results the strain was identified as M. odoratimimus PR63039 and the genome analysis revealed antibiotic resistance genes associated with resistance to beta-lactams (bla OXA-347, bla MUS-1, bla EBR-1), tetracyclines (tetX), sulfonamides (sul2), macrolides (ereD), (ermF).

Carbapenem Resistance among Marine Bacteria-An Emerging Threat to the Global Health Sector

The emergence of antibiotic resistance among pathogenic microorganisms is a major issue for global public health, as it results in acute or chronic infections, debilitating diseases, and mortality. Of particular concern is the rapid and common spread of carbapenem resistance in healthcare settings. Carbapenems are a class of critical antibiotics reserved for treatment against multidrug-resistant microorganisms, and resistance to this antibiotic may result in limited treatment against infections. In addition to in clinical facilities, carbapenem resistance has also been identified in aquatic niches, including marine environments. Various carbapenem-resistant genes (CRGs) have been detected in different marine settings, with the majority of the genes incorporated in mobile genetic elements, i.e., transposons or plasmids, which may contribute to efficient genetic transfer. This review highlights the potential of the marine environment as a reservoir for carbapenem resistance and provides a general overview of CRG transmission among marine microbes.

Metallo-β-lactamases in the Age of Multidrug Resistance: From Structure and Mechanism to Evolution, Dissemination, and Inhibitor Design

Antimicrobial resistance is one of the major problems in current practical medicine. The spread of genes coding for resistance determinants among bacteria challenges the use of approved antibiotics, narrowing the options for treatment. Resistance to carbapenems, last resort antibiotics, is a major concern. Metallo-β-lactamases (MBLs) hydrolyze carbapenems, penicillins, and cephalosporins, becoming central to this problem. These enzymes diverge with respect to serine-β-lactamases by exhibiting a different fold, active site, and catalytic features. Elucidating their catalytic mechanism has been a big challenge in the field that has limited the development of useful inhibitors. This review covers exhaustively the details of the active-site chemistries, the diversity of MBL alleles, the catalytic mechanism against different substrates, and how this information has helped developing inhibitors. We also discuss here different aspects critical to understand the success of MBLs in conferring resistance: the molecular determinants of their dissemination, their cell physiology, from the biogenesis to the processing involved in the transit to the periplasm, and the uptake of the Zn(II) ions upon metal starvation conditions, such as those encountered during an infection. In this regard, the chemical, biochemical and microbiological aspects provide an integrative view of the current knowledge of MBLs.

Recognition and binding of FEZ-1 from Legionella with penicillin V and cefoxitin by fluorescence spectra in combination with molecular dynamics simulation

The recognition and interaction of FEZ-1 from Legionella (FEZ-1) with penicillin V(PV) and cefoxitin(CFX) were investigated using fluorescence spectra in combination with molecular dynamics simulation (MD). The results revealed that the CFX bind with FEZ-1 in stronger interaction and induced larger conformational change than PV, despite all being forced by the electrostatic interaction and along with the changing in an environment of amino acid residues as well as the polypeptide skeleton inside the FEZ-1. Moreover, only the loop1, loop2, and N-terminal were observed locating near the binding pocket of FEZ-1, consisting of a flexible "gate-like" zone with better adaptability that controlled the entrance of antibiotic into the pocket by allowing the newly introduced antibiotic to match the pocket better through the conformational changes of these three substructures in the binding procedure. The current study may provide some valuable information on the antibiotic hydrolytic process by metallo-beta-lactamase and thus the references for the development of new antibiotics for super bacteria.

Gardener's Nightmare: A Rare Case of Myroides-Induced Septic Shock

Myroides species, an uncommon clinical isolate, generally found in contaminated sources of environment, is an emerging source of infections, especially amongst immunocompromised patients. Though only 54 cases have been reported to our knowledge, the emergence of pan-resistance to antibiotics remains a concern that may burden healthcare and require awareness. We present the case of an elderly female who despite being home-bound, without any environmental exposure, contracted Myroides septicemia that progressed to septic shock and showed resistance to usual empiric antibiotics. In our case, the patient was exposed to contaminated soil via her family and was successfully treated with carbapenem. The case provides awareness amongst clinicians to suspect this emerging yet threatening infection within immunocompromised patients.

A Healthcare-Associated Outbreak of Urinary Tract Infections Due to Myroides odoratimimus

Myroides spp. are low-grade opportunistic pathogens. Outbreaks due to Myroides spp. have rarely been described in the literature to date. We report a healthcare-associated outbreak of urinary tract infections (UTIs), caused by Myroides odoratimimus, in a Turkish hospital. As of March 2019 until May 2019, 6 strains of M. odoratimimus were isolated from the urine samples of patients, all of whom were hospitalized in intensive care units. After identification and antibiotic susceptibility testing using the VITEK 2 system, MALDI-TOF-MS and 16S rRNA-based sequencing methods were performed for confirmation and species-level identification. Pulsed-field gel electrophoresis (PFGE) was performed in order to investigate the clonal relatedness of the isolates. All the patients were immunocompromised and underwent urinary catheterization. None of the patients had urinary neoplasm, surgery, or calculi. VITEK 2 and MALDI-TOF-MS systems revealed that the isolates belonged to the Myroides genus; however, the aforementioned systems neglected to identify the isolates at the species level. The isolates were all successfully identified as M. odoratimimus through 16S rRNA-based sequencing. The isolates were resistant to every antibiotic tested. All isolates had an indistinguishable PFGE pattern, thus indicating cross-transmission between cases. Although M. odoratimimus is rarely isolated from human specimens, clinicians should be aware of its ability to cause UTIs and infectious outbreaks.

Non-Fermenting Gram Negative Bacteria as Uropathogens in Causing Urinary Tract Infection and its Antimicrobial Susceptibility Pattern at A Tertiary Care Centre of South India

Non fermenting gram-negative bacilli (NFGNB) are recently striving as uropathogens. The present study was conducted to isolate the common species of bacteria in NFGNB causing urinary tract infection (UTI) and its correlation with comorbid conditions and to study the antibacterial susceptibility pattern. This retrospective study was done at the diagnostic Microbiology laboratory of a tertiary care hospital. Urine samples were collected for the period of six months. These samples were plated on blood agar and MacConkey agar and incubated at 37°C for 18–24 hr under aerobic conditions. Identification of NFGNB was done by Gram staining and MALDI-TOF (Matrix- Assisted Laser Desorption/ Ionization- Time of Flight, Biomerieux- Diagnostics). Antibiotic sensitivity testing was done by Vitek® 2 system (Biomerieux- Diagnostics) using N 281 card. Data was analyzed using SPSS IBM version 16. Out of the total 16,413 non repetitive urine samples that were received in the laboratory, 318 had significant bacteriuria. NFGNB were identified in 108 (33.9%) of all the urine samples with significant bacteriuria. Prevalence of non-fermenters in our study was 0.6%. NFGNB were more frequently isolated in the females and also in the age group of more than 50 years. Eighty five (78.70%) had comorbid conditions. P. aeruginosa and A. baumannii were the most common organism isolated among NFGNB. Pseudomonas aeruginosa isolates showed high susceptibility to imipenem (80.2%) and amikacin (66.6%). NFGNB although seen frequently in females and in age group of 50 years and above, clinical correlation with comorbid condition is essential to label it as uropathogens. Amikacin or imipenem may be the empirical drug of choice.

Molecular Epidemiology of Myroides odoratimimus in Nosocomial Catheter-Related Infection at a General Hospital in China

Purpose

Catheter-related infection (CRI) is one of the most frequent causes of hospitalizations for immunocompromised patients. A major challenge is the increased prevalence of Myroides odoratimimus. The purpose of the present study was to evaluate the clinical features and molecular characteristics of M. odoratimimus collected from a general hospital in Shanghai, China.

Patients and Methods

From July 2015 to August 2016, a total of 22 isolates of M. odoratimimus were collected from inpatients respectively from the biliary and pancreatic surgery (6/22) and the urology department (16/22). Clonal relatedness among the isolates was assessed using pulsed-field gel electrophoresis (PFGE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Moreover, the antimicrobial susceptibility tests were carried out using the Clinical and Laboratory Standards Institute (CLSI) broth microdilution method. The presence of antibiotic resistance genes was screened using the polymerase chain reaction (PCR) assay. Additionally, protein structure prediction was analyzed using PSIPRED and RaptorX.

Results

PFGE differentiated these isolates into six possibly related clones from two different departments obtained during a distinct period, indicating clonal dissemination in the two departments. We compared the dendrograms of M. odoratimimus isolates obtained by MALDI-TOF MS with those obtained by PFGE and found that the coincidence rate between them was only 68.2%. All the M. odoratimimus isolates were highly resistant to most available antibiotics, including carbapenems. Furthermore, chromosome-encoded β-lactamases MUS-1 was confirmed by PCR in 6 of 22 Myroides odoratimimus isolates. Herein, we also reported a novel variant of bla_MUS-1 in the remaining 16 isolates, which encodes MUS-3 protein at position 60 (Valine to Alanine), differing from the structure of MUS-1.

Conclusion

The opportunistic and extensively antibiotic-resistant Myroides odoratimimus has a small range of epidemics in these two different departments. Clinicians should be aware that M. odoratimimus may induce a severe nosocomial outbreak of catheter-related infections, particularly in immunocompromised patients.

A healthcare-associated outbreak of urinary tract infections due to Myroides odoratimimus

Myroides spp. are low-grade opportunistic pathogens. There were only a few outbreaks due to Myroides spp. described in the literature to date. We report a healthcare-associated outbreak of urinary tract infections caused by Myroides odoratimimus in a Turkish hospital. From March to May 2019, six strains of M. odoratimimus were isolated from the urine samples of patients hospitalized in the intensive care units (ICUs). After identification and antibiotic susceptibility testing with VITEK 2 system, MALDI-TOF-MS and 16S rRNA based sequencing methods were performed for confirmation and species level identification. Pulsed-field gel electrophoresis (PFGE) was used to investigate clonal relatedness of the isolates. All the patients were immunocompromised and underwent urinary catheterization. None of them had urinary neoplasm, surgery or calculi. VITEK 2 and MALDI-TOF-MS systems revealed that the isolates belong to the Myroides genus but lacked to identify the isolates at the species level. 16S rRNA based sequencing successfully identified all the isolates as M. odoratimimus. The isolates were resistant to all antibiotics tested. All isolates had indistinguishable PFGE pattern indicating cross-transmission between cases. Although M. odoratimimus is rarely isolated from human specimens, clinicians should be aware of its ability to cause UTIs and outbreaks.

Diversity and Genetic Basis for Carbapenem Resistance in a Coastal Marine Environment

Resistance to the "last-resort" antibiotics, such as carbapenems, has led to very few antibiotics being left to treat infections by multidrug-resistant bacteria. Spread of carbapenem resistance (CR) has been well characterized for the clinical environment. However, there is a lack of information about its environmental distribution. Our study reveals that CR is present in a wide range of Gram-negative bacteria in the coastal seawater environment, including four phyla, eight classes, and 30 genera. These bacteria were likely introduced into seawater via stormwater flows. Some CR isolates found here, such as Acinetobacter junii, Acinetobacter johnsonii, Brevundimonas vesicularis, Enterococcus durans, Pseudomonas monteilii, Pseudomonas fulva, and Stenotrophomonas maltophilia, are further relevant to human health. We also describe a novel metallo-β-lactamase (MBL) for marine Rheinheimera isolates with CR, which has likely been horizontally transferred to Citrobacter freundii or Enterobacter cloacae In contrast, another MBL of the New Delhi type was likely acquired by environmental Variovorax isolates from Escherichia coli, Klebsiella pneumoniae, or Acinetobacter baumannii utilizing a plasmid. Our findings add to the growing body of evidence that the aquatic environment is both a reservoir and a vector for novel CR genes.IMPORTANCE Resistance against the "last-resort" antibiotics of the carbapenem family is often based on the production of carbapenemases, and this has been frequently observed in clinical samples. However, the dissemination of carbapenem resistance (CR) in the environment has been less well explored. Our study shows that CR is commonly found in a range of bacterial taxa in the coastal aquatic environment and can involve the exchange of novel metallo-β-lactamases from typical environmental bacteria to potential human pathogens or vice versa. The outcomes of this study contribute to a better understanding of how aquatic and marine bacteria can act as reservoirs and vectors for CR outside the clinical setting.

Examining transmission of gut bacteria to preserved carcass via anal secretions in Nicrophorus defodiens

Direct transmission of bacteria to subsequent generations highlights the beneficial nature of host-bacteria relationships. In insects, this process is often mediated by the production of microbe-containing secretions. The objective of this study was to determine if the burying beetle, Nicrophorus defodiens, utilizes anal secretions to transmit adult digestive tract bacteria onto a small vertebrate carcass; thus creating the potential to aid in carcass preservation or pass digestive tract bacteria to their larval offspring. Using high-throughput Illumina sequencing of the 16S rRNA gene, we characterized bacterial communities of adult beetle digestive tracts, their anal secretions, and prepared mouse carcasses. We also examined unprepared carcass bacterial communities as a means to interpret community shifts that take place during carcass preservation. We found a vast reduction in diversity on prepared carcasses after anal secretion application. Overall, there was little similarity in bacterial communities among adult digestive tracts, anal secretions, and prepared carcasses, suggesting bacterial communities found in adult digestive tracts do not successfully colonize and achieve dominance on prepared carcasses by way of beetle anal secretions. We concluded that N. defodiens does not transmit their digestive tract bacterial communities to prepared carcasses in a wholesale manner, but may transmit key microbes, including core microbiome members, to preserved carcasses that may ultimately act to sustain larvae and serve as inocula for larval digestive tracts.

Myroides injenensis Bacteremia and Severe Cellulitis

Myroides spp. are environmental bacterial organisms that rarely cause disease in humans. Myroides spp. infections are infrequently reported in the literature, and Myroides injenensis infections are quite uncommon. Myroides spp. usually infect immunocompromised hosts and can have highly resistant antibiotic susceptibility patterns. Here we report a case of Myroides injenensis bacteremia and severe cellulitis in a patient with cirrhosis and review the literature of other Myroides spp. infections.

Diversity and Proliferation of Metallo-β-Lactamases: a Clarion Call for Clinically Effective Metallo-β-Lactamase Inhibitors

The worldwide proliferation of life-threatening metallo-β-lactamase (MBL)-producing Gram-negative bacteria is a serious concern to public health. MBLs are compromising the therapeutic efficacies of β-lactams, particularly carbapenems, which are last-resort antibiotics indicated for various multidrug-resistant bacterial infections. Inhibition of enzymes mediating antibiotic resistance in bacteria is one of the major promising means for overcoming bacterial resistance. Compounds having potential MBL-inhibitory activity have been reported, but none are currently under clinical trials. The need for developing safe and efficient MBL inhibitors (MBLIs) is obvious, particularly with the continuous spread of MBLs worldwide. In this review, the emergence and escalation of MBLs in Gram-negative bacteria are discussed. The relationships between different class B β-lactamases identified up to 2017 are represented by a phylogenetic tree and summarized. In addition, approved and/or clinical-phase serine β-lactamase inhibitors are recapitulated to reflect the successful advances made in developing class A β-lactamase inhibitors. Reported MBLIs, their inhibitory properties, and their purported modes of inhibition are delineated. Insights into structural variations of MBLs and the challenges involved in developing potent MBLIs are also elucidated and discussed. Currently, natural products and MBL-resistant β-lactam analogues are the most promising agents that can become clinically efficient MBLIs. A deeper comprehension of the mechanisms of action and activity spectra of the various MBLs and their inhibitors will serve as a bedrock for further investigations that can result in clinically useful MBLIs to curb this global menace.

Myroides odoratimimus urinary tract infection in an immunocompromised patient: an emerging multidrug-resistant micro-organism

Background

Myroides spp. are common environmental organisms and they can be isolated predominantly in water, soil, food and in sewage treatment plants. In the last two decades, an increasing number of infections such as urinary tract infections and skin and soft tissue infections, caused by these microorganisms has been reported. Selection of appropriate antibiotic therapy to treat the infections caused by Myroides spp. is difficult due to the production of a biofilm and the organism's intrinsic resistance to many antibiotic classes.

Case presentation

We report the case of a 69-year-old immunocompromised patient who presented with repeated episodes of macroscopic haematuria, from Northern Italy.A midstream urine sample cultured a Gram negative rod in significant amounts (> 105 colony-forming units (cfu)/mL), which was identified as Myroides odoratimimus. The patient was successfully treated with trimethoprim/sulfamethoxazole after antibiotic susceptibility testing confirmed its activity.

Conclusion

This case underlines the emergence of multidrug resistant Myroides spp. which are ubiquitous in the environment and it demands that clinicians should be more mindful about the role played by atypical pathogens, which may harbour or express multidrug resistant characteristics, in immunocompromised patients or where there is a failure of empiric antimicrobial therapy.

Extensively drug-resistant Myroides odoratimimus - a case series of urinary tract infections in immunocompromised patients

Purpose

We report an outbreak of urinary tract infections (UTIs) caused by Myroides odoratimimus, which occurred in the largest clinical hospital in western Romania.

Patients and methods

From June to August 2017, four strains of M. odoratimimus were isolated from the urine samples of patients hospitalized in the urology, diabetes, and surgery departments. Hospital records of all patients whose urine cultures were positive for M. odoratimimus were reviewed retrospectively. We also reviewed the cases reported in the literature.

Results

All UTIs, except one, were hospital-acquired infections. All patients with M. odoratimimus UTIs were immunocompromised. Three patients underwent urinary catheterization with a Foley’s catheter upon admission in the emergency department and one presented for replacement of ureterostomy tubes. All Myroides isolates were resistant to almost all the tested antibiotics. Two patients were successfully treated with tigecycline and one was receiving antimicrobial treatment for another infection at the time of isolation of the microorganism.

Conclusion

Although M. odoratimimus is an uncommon pathogen, clinicians should be aware of its ability to cause UTI outbreaks, especially in the immunocompromised population. Due to its multi-drug resistance, it is important to rapidly identify Myroides spp. in order to choose the best treatment regimen.

Whole-genome sequencing of a large collection of Myroides odoratimimus and Myroides odoratus isolates and antimicrobial susceptibility studies

The genus Myroides comprises several species of Gram-negative, non-motile, and non-fermenting bacteria, which have been regarded as non-pathogenic for decades. Multiple recent reports, however, underscore the pathogenic potential that Myroides sp. possesses for humans. These bacteria seem to be resistant to a wide range of antibiotics (including ß-lactams and aminoglycosides). Therefore, treatment options are limited. Knowledge of antimicrobial resistance, however, is based on only one meaningful comprehensive study and on data published from case reports. This lack of data motivated us to test 59 strains from our Myroides collection (43 M. odoratimimus and 16 M. odoratus) for resistance against 20 commonly used antibiotics. We also performed molecular analyses to reveal whether our bacteria harbor the genus-specific M. odoratimimus metallo-ß-lactamase (MUS-1) or the M. odoratus metallo ß-lactamase (TUS-1), and other ß-lactamases, which may provide an explanation for the extended antimicrobial resistance.

Diversity and regulation of intrinsic β-lactamases from non-fermenting and other Gram-negative opportunistic pathogens

This review deeply addresses for the first time the diversity, regulation and mechanisms leading to mutational overexpression of intrinsic β-lactamases from non-fermenting and other non-Enterobacteriaceae Gram-negative opportunistic pathogens. After a general overview of the intrinsic β-lactamases described so far in these microorganisms, including circa. 60 species and 100 different enzymes, we review the wide array of regulatory pathways of these β-lactamases. They include diverse LysR-type regulators, which control the expression of β-lactamases from relevant nosocomial pathogens such as Pseudomonas aeruginosa or Stenothrophomonas maltophilia or two-component regulators, with special relevance in Aeromonas spp., along with other pathways. Likewise, the multiple mutational mechanisms leading to β-lactamase overexpression and β-lactam resistance development, including AmpD (N-acetyl-muramyl-L-alanine amidase), DacB (PBP4), MrcA (PPBP1A) and other PBPs, BlrAB (two-component regulator) or several lytic transglycosylases among others, are also described. Moreover, we address the growing evidence of a major interplay between β-lactamase regulation, peptidoglycan metabolism and virulence. Finally, we analyse recent works showing that blocking of peptidoglycan recycling (such as inhibition of NagZ or AmpG) might be useful to prevent and revert β-lactam resistance. Altogether, the provided information and the identified gaps should be valuable for guiding future strategies for combating multidrug-resistant Gram-negative pathogens.

New Subclass B1 Metallo-β-Lactamase Gene from a Clinical Pathogenic Myroides odoratus Strain

Myroides odoratus is a low-virulence opportunistic human pathogen. Infections caused by M. odoratus are not common, but reports are increasing in recent years. The biggest challenge for treatment is its resistance to most antibiotics. In 2015, we isolated a pathogenic multidrug-resistant strain of M. odoratus from a urinary tract infection (UTI) patient's urine sample. To report the experience in managing M. odoratus-related UTI and investigate the genetic mechanism of this carbapenem-resistant strain, we conducted a series of microbiological and molecular studies. The bacterial strain was identified as M. odoratus by 16S rRNA gene sequencing. The minimum inhibitory concentrations (MICs) of 17 antimicrobial agents were determined against this strain. Whole-genome sequencing was performed and screened for possible β-lactamase genes. A β-lactamase gene, bla_MOC, was identified by whole-genome sequencing, then cloned and expressed in Escherichia coli DH5α to characterize its function. Antimicrobial susceptibility testing showed that the strain had relatively low MIC to levofloxacin and sulfamethoxazole/trimethoprim (SMZ/TMP). After unsuccessful empirical therapy, the UTI was controlled by levofloxacin in combination with SMZ/TMP. Whole-genome sequencing identified a subclass B1 metallo-β-lactamase gene, bla_MOC, which conferred resistance to most β-lactams except for aztreonam and cefepime. In conclusion, a new β-lactamase gene, bla_MOC, was found in an isolate of M. odoratus. The broad antimicrobial resistance of this isolate is at least attributed partially to this gene.

How to treat a fulminant erysipelas and sepsis caused by Myroides odoratimimus: case report and literature review

We report a case of a 77-year old male who developed a fulminant erysipelas and sepsis, caused by Myroides odoratimimus. Selecting the optimal antibiotic therapy for the treatment of infections with M. odoratimimus is challenging due to limited clinical experience with this micro-organism and its reported multidrug-resistance. Review of previous studies concerning in vitro antibacterial susceptibility and clinical experience with M. odoratimimus resulted in six case reports describing bacteremia, soft tissue and bone infections, pneumonia and urinary tract infections. In vitro susceptibility to aminoglycosides, fluoroquinolones and trimethoprim/sulfamethoxazole is variable. Treatment of M. odoratimimus infections should be based on antimicrobial susceptibility testing results. In a majority of the case reports, including the present one, treatment with fluoroquinolones proved to be a good therapeutic option.

Analysis of resistance genes in pan-resistant Myroides odoratimimus clinical strain PR63039 using whole genome sequencing

To clarify the antibiotic resistance mechanisms of Myroides odoratimimus, pan-resistant M. odoratimimus strain PR63039 was isolated and its genome sequenced and analyzed. Antimicrobial susceptibility testing was conducted using the Kirby-Bauer disk diffusion method, and the Phoenix-100 Automated Microbiology System with a NMIC/ID-4 panel including aminoglycosides, β-lactams, polypeptides, quinolones, sulfonamides, chloramphenicols, and tetracyclines. Single-molecule real-time whole genome sequencing was conducted using the PacBio RSII system, and genome annotation was performed using RAST and IMG ER. To characterize the genome features, a number of databases and software programs, including GC-Profile, CG viewer, the VFDB database, ISfinder, RADB, CARD, ResFinder, and PHAST, were used. M. odoratimimus isolate PR63039 was resistant to almost all antibiotics tested, suggesting pan-drug resistance. The genome consisted of a 4,366,950-bp chromosome and a 90,798-bp plasmid (p63039), which contained a large number of resistance genes and virulence factors. The distribution of the resistance genes was distinctive, and a resistance region, designated MY63039-RR, was identified. RAST analysis indicated that 108 of the annotated genes were potentially involved in virulence, disease, and defense, all of which could be associated with resistance and pathogenicity. Prophage analysis also identified two incomplete prophages in the genome of M. odoratimimus PR63039. Multiple antibiotic-resistance genes were identified, including those associated with resistance to tetracycline (tetX), macrolides (ereB, cfrA, lasE), sulfonamides (sul2, sul3), β-lactams (bla_MUS-1, bla_TUS-1, bla_SFB-1, bla_SLB-1, bla_OXA-209, bla_OXA-347), and chloramphenicol (cat). Further, the presence of 18 antibiotic efflux pump-encoding resistance genes, including acrB, acrD, acrF, adeB, adeG, adeJ, amrB, ceoB, cmeB, mdsB, mexB, mexD, mexF, mtrD, smeE, mdtF, macB, likely accounts for the observed quinolone resistance of strain PR63039. To the best of our knowledge, this is the first report of the presence of the bla_SFB-1, bla_SLB-1, bla_OXA-209, bla_OXA-347, and tetX resistance genes in M. odoratimimus.

Microbiome disruption and recovery in the fish Gambusia affinis following exposure to broad-spectrum antibiotic

Antibiotics are a relatively common disturbance to the normal microbiota of humans and agricultural animals, sometimes resulting in severe side effects such as antibiotic-associated enterocolitis. Gambusia affinis was used as a vertebrate model for effects of a broad-spectrum antibiotic, rifampicin, on the skin and gut mucosal microbiomes. The fish were exposed to the antibiotic in the water column for 1 week, and then monitored during recovery. As observed via culture, viable counts from the skin microbiome dropped strongly yet returned to pretreatment levels by 1.6 days and became >70% resistant. The gut microbiome counts dropped and took longer to recover (2.6 days), and became >90% drug resistant. The resistance persisted at ~20% of skin counts in the absence of antibiotic selection for 2 weeks. A community biochemical analysis measuring the presence/absence of 31 activities observed a 39% change in results after 3 days of antibiotic treatment. The antibiotic lowered the skin and gut microbiome community diversity and altered taxonomic composition, observed by 16S rRNA profiling. A 1-week recovery period did not return diversity or composition to pretreatment levels. The genus Myroides dominated both the microbiomes during the treatment, but was not stable and declined in abundance over time during recovery. Rifampicin selected for members of the family Comamonadaceae in the skin but not the gut microbiome. Consistent with other studies, this tractable animal model shows lasting effects on mucosal microbiomes following antibiotic exposure, including persistence of drug-resistant organisms in the community.

Antibiotic resistance mechanisms of Myroides sp

Bacteria of the genus Myroides (Myroides spp.) are rare opportunistic pathogens. Myroides sp. infections have been reported mainly in China. Myroides sp. is highly resistant to most available antibiotics, but the resistance mechanisms are not fully elucidated. Current strain identification methods based on biochemical traits are unable to identify strains accurately at the species level. While 16S ribosomal RNA (rRNA) gene sequencing can accurately achieve this, it fails to give information on the status and mechanisms of antibiotic resistance, because the 16S rRNA sequence contains no information on resistance genes, resistance islands or enzymes. We hypothesized that obtaining the whole genome sequence of Myroides sp., using next generation sequencing methods, would help to clarify the mechanisms of pathogenesis and antibiotic resistance, and guide antibiotic selection to treat Myroides sp. infections. As Myroides sp. can survive in hospitals and the environment, there is a risk of nosocomial infections and pandemics. For better management of Myroides sp. infections, it is imperative to apply next generation sequencing technologies to clarify the antibiotic resistance mechanisms in these bacteria.

Genomic analysis of the multi-drug-resistant clinical isolate Myroides odoratimimus PR63039

Myroides odoratimimus (M. odoratimimus) has been gradually implicated as an important nosocomial pathogen that poses a serious health threat to immunocompromised patients owing to its multi-drug resistance. However, the resistance mechanism is currently unclear. To clarify the antibiotic resistance and infectivity mechanisms of M. odoratimimus, whole genome sequencing was performed on the multi-drug-resistant M. odoratimimus strain PR63039. The genome sequence was completed with single molecule real-time (SMRT) technologies. Then, annotation was performed using RAST and IMG-ER. A number of databases and software programs were used to analyze the genomic characteristics, including GC-Profile, ISfinder, CG viewer, ARDB, CARD, ResFinder, the VFDB database, PHAST and Progressive Mauve. The M. odoratimimus PR63039 genome consisted of a chromosome and a plasmid. The genome contained a large number of resistance genes and virulence factors. The distribution of the resistance genes was distinctive, and a resistance region named MY63039-RR was found. The subsystem features generated by RAST indicated that the annotated genome had 108 genes that were potentially involved in virulence, disease and defense, all of which had strong associations with resistance and pathogenicity. The prophage analysis showed two incomplete prophages in the genome. The genomic analysis of M. odoratimimus PR63039 partially clarified its antibiotic resistance mechanisms and virulence factors. Obtaining a clear understanding of its genomic characteristics will be conducive to the management of multidrug-resistant M. odoratimimus.

Fatal Case of Pericardial Effusion Due to Myroides Odoratus: A Rare Case Report

Myroides spp., previously known as Flavobacterium odoratum, are rare clinical isolates and are often considered non-pathogenic. Natural habitat includes soil, fresh and marine waters, in foods and in sewage treatment plants. We present an unusual case of fatal pericardial effusion due to Myroides odoratus in a patient suffering from chronic kidney disease and undergoing maintenance haemodialysis. This case is presented to show the increasing incidence of rare isolates causing localized and systemic infections and due to their high intrinsic resistance to many antibiotics they can be fatal. Thus isolation of these pathogens is of great clinical importance.

MUS-2, a novel variant of the chromosome-encoded β-lactamase MUS-1, from Myroides odoratimimus

The aim of the present study was to investigate the molecular mechanism of carbapenem resistance of three imipenem-resistant isolates of Myroides odoratimimus recovered from two livestock farms of cows and pigeons by rectal swab in Lebanon in January 2014. Investigation of imipenem resistance of these isolates using the modified Hodge test, the EDTA test, the modified CarbaNP test and the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry Ultraflex assay showed a carbapenemase activity due to the presence of a chromosome-encoded β-lactamase MUS, verified by PCR. However amplification and sequencing of this chromosomal gene showed a novel variant of it designated MUS-2 by the curators of the Lahey database of β-lactamases (http://www.lahey.org/Studies/webt.asp). Cloning of the bla_MUS-2 was performed, followed by protein expression in Escherichia coli TOP 10. Pulsed-field gel electrophoresis clearly showed that the three isolates belonged to the same clone. This study reports a novel variant of the chromosome-encoded bla_MUS-1 associated with carbapenem resistance in Myroides odoratimimus and shows that animals may represent a reservoir of bacteria harbouring several variants of resistance genes.

Acquired metallo-β-lactamases and their genetic association with class 1 integrons and ISCR elements in Gram-negative bacteria

ABSTRACT 

Metallo-β-lactamases (MBLs) can hydrolyze almost all β-lactam antibiotics and are resistant to clinically available β-lactamase inhibitors. Numerous types of acquired MBLs have been identified, including IMP, VIM, NDM, SPM, GIM, SIM, DIM, KHM, TMB, FIM and AIM. IMPs and VIMs are the most frequent MBLs and disseminate in members of the family Enterobacteriaceae, Pseudomonas spp. and Acinetobacter spp. Acquired MBL genes are often embedded in integrons, and some are associated with insertion sequence (IS) elements. The class 1 integrons and IS common region (ISCR) elements are usually harbored in transposons and/or plasmids, forming so-called mobile vesicles for horizontal transfer of captured genes between bacteria. Here, we review the MBL superfamily identified in Gram-negative bacteria, with an emphasis on the phylogeny of acquired MBLs and their genetic association with class 1 integrons and IS common region elements.

MYROIDES INFECTION IN A BABOON AFTER PROLONGED PIG KIDNEY GRAFT SURVIVAL

BACKGROUND

Immunosuppressed patients and experimental nonhuman primates are at risk of opportunistic infection. We report a Myroides spp infection in an immunosuppressed baboon that had received a life-supporting kidney from a genetically-engineered pig.

CASE REPORT

The baboon received a costimulation blockade-based immunosuppressive regimen as well as two anti-inflammatory agents (tocilizumab and etanercept). Although the pig kidney functioned well, approximately four months after the transplant the baboon became less active and ate and drank poorly. On day 136, it collapsed and died despite inotropic and fluid support. A blood culture drawn before death grew Myroides spp.

DISCUSSION AND CONCLUSIONS

To our knowledge, Myroides spp has not been reported as a cause of opportunistic infection in either patients with organ allotransplants or experimental animals. We summarize what is known about this rare organism, and suggest it should be considered in any immunocompromised patient or animal. In the present case, we suggest the baboon died of circulatory shock following infection through an indwelling intravenous catheter.

Fatal case of necrotizing fasciitis due to Myroides odoratus

Myroides sp., previously known as Flavobacterium odoratum, is a relatively unknown organism with unclear human pathogenicity. While Myroides sp. has been implicated in human infections, many reports have described the organism as a relatively avirulent opportunistic pathogen. We present an unusual case of rapidly fatal necrotizing fasciitis and septic shock due to Myroides odoratus. Our case demonstrates the pathogenicity of Myroides, and highlights potential risk factors for infection including underlying liver disease and open wounds. The recognition of Myroides is of particular importance given its resistance to multiple antibiotics. We review the literature on Myroides sp. skin and soft tissue infections, including necrotizing forms, and discuss the clinical presentation and management of this potentially emerging pathogen.

Comparison of VITEK2, MALDI-TOF MS, and 16S rDNA sequencing for identification of Myroides odoratus and Myroides odoratimimus

The genus Myroides comprises the 2 medically relevant species Myroides odoratus and Myroides odoratimimus that are rare opportunistic pathogens and cause infections in immunocompromised patients. A fast identification of Myroides is of importance because these bacterial strains show multiple resistance against antibiotics and therefore limit treatment options. They are associated, for instance, with urinary tract infections, sepsis, meningitis, pneumonia, and infectious cellulitis. Since more and more Myroides spp. are being described, additional potentially pathogenic bacteria may be identified in the future demanding the need for fast and reliable identification methods at species level. However, to date, only molecular approaches meet these demands. In this study, we, therefore, attempt to define an appropriate method other than DNA fingerprinting that will permit a comparable efficacy and, possibly, a more economical strain identification. For this purpose, we compared 2 widely used automated diagnostic systems (VITEK 2 [bioMérieux, Nürtingen, Germany] and Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) [Bruker Daltonics, Bremen, Germany]) and correlated the results to 16S rDNA sequencing data. In total, we analyzed 22 strains collected in the course of routine diagnostics. In this study, we demonstrate that VITEK 2 reliably identifies the genus Myroides but cannot differentiate between M. odoratimimus and M. odoratus. In contrast to this, both MALDI-TOF MS and 16S rDNA sequencing efficiently distinguish between the 2 species.

Myroides odoratimimus soft tissue infection in an immunocompetent child following a pig bite: case report and literature review

Members of the genus Myroides are aerobic Gram-negative bacteria that are common in environmental sources, but are not components of the normal human microflora. Myroides organisms behave as low-grade opportunistic pathogens, causing infections in severely immunocompromised patients and rarely, in immunocompetent hosts. A case of Myroides odoratimimus cellulitis following a pig bite in an immunocompetent child is presented, and the medical literature on Myroides spp. soft tissue infections is reviewed.

Relationship between plasmid occurrence and antibiotic resistance in Myroides odoratimimus SKS05-GRD isolated from raw chicken meat

Fifteen flavobacterium strains were isolated from raw chicken meat, raw goat meat and poultry soil in Coimbatore, Tamil Nadu. Most of the isolates developed yellow pigmented colonies with mucoid-spreading edges on food flavobacterium medium. The flavobacteria were Gram-negative rods and failed to produce indole and were non-fermentative. Moreover, they produced a rich array of enzymes such as amylase, lipase, catalase, urease, gelatinase, DNase, and oxidase. Phylogenetic analyses of the strain SKS05-GRD based on 16S rRNA gene sequences revealed the bacterium as Myroides odoratimimus (nucleotide sequence accession number JQ178355). Antimicrobial susceptibility test for M. odoratimimus SKS05-GRD and other strains were assessed by disc diffusion method. M. odoratimimus SKS05-GRD showed wide resistance to the antibiotics such as amikacin, ampicillin, cefadroxil, cefoperazone, ceftazidine, ceftriaxone, netillin and gentamicin. M. odoratimimus was subjected to plasmid isolation and plasmid curing to seek the relationship between plasmid and antibiotic resistance. Plasmid curing was done by using ethidium bromide and was found to be effective at 300 and 500 μg/ml. Assessment of antibiotic sensitivity of M. odoratimimus SKS05-GRD showed sensitivity to amikacin, gentamicin and kanamycin confirming that resistance to these three antibiotics is plasmid mediated and other antibiotic resistance are chromosomal mediated.