Introduction

Myroidesspp was initially placed under Flavobacterium odoratum but later excluded from this genus by Bernardet et al., due to important genomic and phenotypic differences. They are considered as low-grade pathogen but can cause serious infections in immunocompromised patients. They are Gram-negative bacilli, strictly aerobic, non-motile, oxidase positive with yellow pigmentation and a characteristic fruity odour.

Here we are presenting a case report of urinary tract infection (UTI) caused by this emerging pathogen in an immunocompetent patient.

Case

A 62-year man of Delhi presented to Surgery Emergency Department with heaviness in lower abdomen and recurrent urinary retention with catheter in-situ. He was a follow up case of BPH (Benign Prostatic Hyperplasia). He first came to hospital in November 2022 with burning micturition and acute retention of urine. On examination, there was tenderness in the suprapubic area. A urinary Foley’s catheter was positioned. On Ultrasonography, prostate was enlarged (grade 2) in size 38×49×45mm, vol 43cc with normal shape and echogenicity and no abnormality detected in other organs. Biopsy of Prostate showed features of BPH with chronic prostatitis and no evidence of malignancy. He was subsequently advised for TURP (Transurethral Resection of Prostate) and referred for pre anaesthetic check-up (PAC). During PAC, he was incidentally diagnosed as Hepatitis C positive. His blood counts revealed haemoglobin 11.8gm/dl, White Blood Cell count (WBC count) of 6500 /mm3, Platelet Count 1.44 lac/ mm³, AEC 370, PT INR 13.7/0.9, Blood urea 26.82, S. Creatinine 0.82, S. Na/K 133/4.19, S.bilirubin 0.82, SGOT 84, SGPT 62 and SAP 73. Urine routine microscopy showed WBC count of 15-20/ HPF, RBCs- 0/HPF and a positive Leukocyte Esterase test.Urine culture reported Pseudomonas spp sensitive to only ciprofloxacin and resistant to Imipenem, Amikacin, Gentamicin, Tobramycin, Ceftazidime.He was treated with tab Ciprofloxacin 500 mg BD for 14 days, and referred to urologist.

Subsequently, he came in December with burning micturition. Urine culture reported no growth. The catheter was reinserted and he was readvised for TURP.

The patient reported again in the mid of January with lower abdomen heaviness and urinary retention. On admission, he was afebrile with stable vitals. The indwelling catheter was replaced and urine sample was sent for culture and sensitivity.

Urine sample was inoculated on Blood agar and MacConkey’s agar and incubated at 37 ⁰C for 24hrs. After the incubation time, a pure growth with a colony count of >100,000 CFU/ml of nonlactose fermenting colony was observed. The colonies appeared round, translucent with a yellow tinge and had a fruity odour. It was catalase and oxidase positive and non-fermentative. The organism was provisionally identified as Pseudomonasspp but it was non- motile and thereafter subjected to MALDI-TOF which confirmed the organism as Myroides spp. The antibiotic susceptibility testing was done by CLSI guidelines, using Kirby Bauer disc diffusion method. The susceptibility profile was as follows: susceptible to Aztreonam, resistant to Amikacin, Gentamicin, Ceftazidime, Tobramycin, Nitrofurantoin, Ciprofloxacin. Colistin sensitivity was performed by Colistin agar dilution method and was reported as resistant.The patient improved clinically on IV Aztreonam 2 g TDS for 5 days anddischarged with referral to urologist for TURP. The patient was subsequently lost to follow up.

Discussion

Myroidesspp are part of normal flora and hardly known to cause infection. They are low grade opportunistic pathogens mostly affecting immunosuppressed patients. They cause UTI in patients with Foleys catheter, urinary retention, chronic nephritis, calculus and immunocompromised conditions [1]. Due to its recently emerging nature and limited data, it is being misidentified by conventional methods. With the advent of automated methods like Vitek 2 MS and MALDI-TOF mass spectrometry, there is an increase in the detection of these atypical pathogens. Thus, timely and correct identification is helpful for antimicrobial stewardship and hospital infection control.

Although UTI associated with Myroidesspp is commonly reported in immunocompromised individuals, here we present a unique case report of this infection in an immunocompetent patient [2].

Prolonged urinary catheterisation, long term hospitalization and various underlying comorbidities serve as important risk factors for acquisition of infection by this organism.  In our patient, multiple episodes of urinary retention due to BPH serves as the single most important contributing factor for this infection. Similarly, in one study reported from Romania, two patients had urological comorbidities. One had TURP for benign prostatic hyperplasia with COPD, for which he was on longterm corticosteroid treatment and was admitted for acute urinary retention. The other patient had undergone a radical cystectomy with bilateral cutaneous ureterostomy for a muscle-invasive bladder cancer [3].

Our patient has a history of repeated urinary catheterizations which may lead to formation of biofilm which serves as an important virulence factor by increasing its pathogenic potential and contributes to multi drug resistance and ultimately therapeutic failure. Biofilm formation helps it to escape host defence and their higher resistance to antibacterial agents because sessile cell express properties which are different from the properties of planktonic cells [4].

In most reported cases, Myroidesspp have been found to be multi or pan drug resistant. In our case, the organism was also found to be extensively drug resistant and susceptible only to Aztreonam which is in concordance with the studies by Licker et al,[3]. In contrast to the above findings, a study by Romano et al,[5] demonstrated Myroidesspp as susceptible to Ciprofloxacin and resistant to Aztreonam. Our isolate was resistant to antipseudomonal Cephalosporins, Ceftazidime and Colistin. The uncontrolled and excessive use of fluoroquinolones and aminoglycosides as first line agents for complicated UTI without proper identification of the causative agent further aggravates the problem of increasing antimicrobial resistance in hospital settings.

Hence, choosing the appropriate antimicrobial treatment can be quite challenging because of the limited clinical experience with this emerging atypical uro-pathogen and further compounded by the resource limited settings in the developing countries. In our case, the infection has not been attributed to any definitive source but prolonged catheterization served as the single most important contributing risk factor for the acquisition of this uro-pathogen.

Conclusion

Although Myroides spp. are uncommon pathogens, clinicians should be aware of its ability to cause UTI even in the immunocompetent population. It is important to identify Myroides spp. infections rapidly in order to choose the best therapeutic regimen, considering the wide range of antibiotic resistance of these microorganisms.

Consent for publication:  “Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.”

Funding: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Declaration of competing interest: The authors have no conflict of interest to disclose.

Author contribution:

Iram Rafique– Study design, data collection, data analysis, writing.

Sanchita Tuteja-Data analysis and writing.

Monica Chaudhary- analysis and supervision.

Rahul lal- Supervision

Sonal Saxena- Supervision

Acknowledgements: We thank our colleagues for their support.

References

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3. Licker M, Sorescu T, Rus M, Cirlea N, Horhat F, et al., (2018) Extensively drug-resistant Myroidesodoratimimus - a case series of urinary tract infections in immunocompromised patients. Infect Drug Resist 11:743-749.
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