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

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.

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.

A case series and literature review of infections due to Myroides spp.: identification of contributing factors and emerging antibiotic susceptibility trends

Introduction

Infections forby Myroides spp. can lead to significant morbidity and mortality, particularly in immunocompromised patients with underlying co-morbidities. Recent reports have highlighted its intrinsic and acquired drug resistance, making it a particularly challenging infectious agent to combat.

Methods

Myroides spp. isolated and reported in clinically significant urine samples were considered for the study. Identification of the organism was done via the VITEK 2C system. Antibiotic susceptibility testing was done using both manual and automated methods following Clinical and Laboratory Standards Institute (CLSI) guidelines. Existing literature was searched on MEDLINE using PubMed.

Results

We present a series of five catheter-associated urinary tract infections due to Myroides odoratimimus , with sensitivity to only minocycline. This is the first case from Western India, and the third case in the existing literature that shows Myroides sensitivity only to minocycline. Our literature review is the first to systematically describe contributory factors to infection, allowing us to devise a clinically relevant tool that delineates contributory factors and efficacious drugs in Myroides spp. infection.

Conclusion

Myroides spp. infections, previously considered rare and opportunistic, need cognizance and diagnostic suspicion especially in particular associated conditions.

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.

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.

Structural and biochemical characterization of the environmental MBLs MYO-1, ECV-1 and SHD-1

BACKGROUND

MBLs form a large and heterogeneous group of bacterial enzymes conferring resistance to β-lactam antibiotics, including carbapenems. A large environmental reservoir of MBLs has been identified, which can act as a source for transfer into human pathogens. Therefore, structural investigation of environmental and clinically rare MBLs can give new insights into structure-activity relationships to explore the role of catalytic and second shell residues, which are under selective pressure.

OBJECTIVES

To investigate the structure and activity of the environmental subclass B1 MBLs MYO-1, SHD-1 and ECV-1.

METHODS

The respective genes of these MBLs were cloned into vectors and expressed in Escherichia coli. Purified enzymes were characterized with respect to their catalytic efficiency (kcat/Km). The enzymatic activities and MICs were determined for a panel of different β-lactams, including penicillins, cephalosporins and carbapenems. Thermostability was measured and structures were solved using X-ray crystallography (MYO-1 and ECV-1) or generated by homology modelling (SHD-1).

RESULTS

Expression of the environmental MBLs in E. coli resulted in the characteristic MBL profile, not affecting aztreonam susceptibility and decreasing susceptibility to carbapenems, cephalosporins and penicillins. The purified enzymes showed variable catalytic activity in the order of <5% to ∼70% compared with the clinically widespread NDM-1. The thermostability of ECV-1 and SHD-1 was up to 8°C higher than that of MYO-1 and NDM-1. Using solved structures and molecular modelling, we identified differences in their second shell composition, possibly responsible for their relatively low hydrolytic activity.

CONCLUSIONS

These results show the importance of environmental species acting as reservoirs for MBL-encoding genes.

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.

Wound infection caused by Photobacterium damselae in a 32-year-old woman: case report and review of the literature

The case of a 32-year-old woman is reported, who was affected by a persisting wound infection caused by Photobacterium damselae after an accident in the Mediterranean Sea. Besides the clinical case, microbiological characteristics based on the phenotypic and genotypic description of the isolate (including whole genome data) are presented and discussed.

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.

Identification of a mobilizable, multidrug-resistant genomic island in Myroides odoratimimus isolated from Tibetan pasture

Strains of the environmental bacterium Myroides odoratimimus can cause human infections. However, treating M. odoratimimus infections can be difficult because of multidrug resistance in this organism. In this study, we isolated strain M. odoratimimus G13 from pastureland in Tibet, China. The minimum inhibitory concentration analysis suggested that strain G13 has resistance to multiple antibiotics, with an MIC for tetracycline of 168 mg/L. Whole-genome sequencing and bioinformatic analysis revealed that the genome of G13 was rich in virulence factor-encoding genes and antibiotic resistance genes (ARGs). The mobilizable genomic island MGI1313 was also identified and characterized, and six resistance genes related to four types of antibiotics were annotated in MGI1313. Conjugation assays indicated that MGI1313 could be transferred from G13 to Escherichia coli 25DN by horizontal gene transfer, resulting in multidrug-resistant E. coli conjugants. In conclusion, multidrug-resistant M. odoratimimus G13 and the mobility of MGI1313 raise the risk of difficult-to-treat bacterial infections and should be under close surveillance.

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.

First report of Myroides phaeus bacteraemia identified by Polymerase chain reaction and genetic sequencing

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We report the first case of Myroides phaeus isolated from blood, causing bacteremia in an immunocompromised patient.

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The relevance of this species is that most strains are resistant to multiple drugs.

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For identification it was used MicroScan Panel in addition to PCR – genetic sequencing.

We report the first case of Myroides phaeus isolated from blood, causing bacteremia in an immunocompromised patient using the automated MicroScan Walk Away 96 system, followed by bacterial identification by amplification-sequencing of the 16S rDNA. The sequences obtained were compared with the reference sequence of the BLAST ® platform - National Library of Medicine, USA, and the isolation was identified as Myroides phaeus strain with 99.67 % identity in Blast report. In the literature we did not find previous reported cases of infections by this bacterium, however its pathogenic role is still controversial; therefore, this isolation alerts us to carry out an exhaustive surveillance of other possible acquisition routes.

How MALDI-TOF mass spectrometry can aid the diagnosis of hard-to-identify pathogenic bacteria - the rare and the unknown

Introduction: Ten years after its introduction into clinical microbiology, MALDI-TOF mass spectrometry has become the standard routine identification tool for bacteria in most laboratories. The technology has accelerated analyses and improved the quality of results. The greatest significance has been observed for bacteria that were challenging to be identified by traditional methods. Areas covered: We searched in existing literature (Pubmed) for reports how MALDI-TOF MS has contributed to identification of rare and unknown bacteria from different groups. We describe how this has improved the diagnostics in different groups of bacteria. Reference patterns for strains which yet cannot be assigned to a known species even enable the search for related bacteria in studies as well as in routine diagnostics. MALDI-TOF MS can help to discover and investigate new species and their clinical relevance. It is a powerful tool in the elucidation of the bacterial composition of complex microbiota in culturomics studies. Expert opinion: MALDI-TOF MS has improved the diagnosis of bacterial infections. It also enables knowledge generation for prospective diagnostics. The term 'hard-to-identify' might only be rarely attributed to bacteria in the future. Novel applications are being developed, e.g. subspecies differentiation, typing, and antibiotic resistance testing which may further contribute to improved microbial diagnostics.

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.

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.