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Kerstersia Gyiorum causing Chronic Otitis Media: Where a Quinolone Does not Work

Juan Manuel García-Lechuz*

Microbiología, Hospital Miguel Servet, Paseo Isabel La Católica, 1, Zaragoza, Spain

*Corresponding Author:
Juan Manuel García-Lechuz
Microbiología, Hospital Miguel Servet, Paseo Isabel La Católica, 1, Zaragoza, Spain
Tel: 34976553790
E-mail: [email protected]

Received date: May 10, 2017; Accepted date: May 19, 2017, Published date: May 25, 2017

Citation: Juan Manuel García-Lechuz (2017) Kerstersia Gyiorum causing Chronic Otitis Media: Where a Quinolone Does not Work. J Infec Dis Treat. 2017, 3:1. doi:10.21767/2472-1093.100033

Copyright: © 2017 García-Lechuz JM. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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Chronic otitis media (COM) is an inflammatory disease which affects the mucosal and bone structures of the medium ear, insidiously, slowly progressive, prone to persist and to produce severe sequelae. Staphylococcus aureus following by gram negative bacillus as Proteus spp., Klebsiella spp., Escherichia spp. and Haemophilus influenza are common pathogens causing COM. Recently some cases of COM produced by less known bacteria have been described. This is the case of the genus Kerstersia which has emerged in the literature causing bacteremia and urinary infection, as well as a causative pathogen of chronic otitis.

We have reviewed five cases as well as our own experience with an 88-year-old man transferred to our hospital suffering from persistent otorrhea, finally diagnosed as COM caused by Kerstersia gyiorum resistant to quinolones. Kerstersia genus belongs to the family Alcaligenaceae. A sample from the ear of our patient was taken and gram-negative rods were observed in the Gram stain. After incubation for 24 h, in all media, abundant slightly convex colonies with extended edges, colorful, were isolated and identified by MALDI-TOF (matrixassisted laser desorption ionization time-of-flight) Biotyper 3.1 as Kerstersia gyiorum (score of 2.3. K. gyiorum identification was confirmed by sequencing of the rRNA 16S gene and comparing of the sequence obtained with those deposited in GenBank with the NCBI BLASTn algorithm. Our case would be the third case resistant to quinolones reported in the literature.


Kerstersia; Chronic otitis; Ciprofloxacin resistant


Chronic otitis media (COM) is an insidious, slowly progressive inflammatory disease affecting the mucosal and bone structures of the medium ear and prone to persist and to produce severe sequelae [1].

Suppurate COM is known as chronic ear discharge through a tympanic drilling, lasting for at least 6 weeks with periods of inactivity [1]. Well-known risk factors for developing a COM are overcrowded living conditions, recurrent respiratory tract infections and smoking [2].

Staphylococcus aureus following by gram negative bacillus as Proteus spp., Klebsiella spp., Escherichia spp. and Haemophilus influenza are common pathogens causing COM. Bacteroides spp. and Fusobacterium spp. are the anaerobes more frequently isolated. There are also mixed infections and several cases of COM produced by less known bacteria as Bordetella, Achromobacter, Alcaligenes and Kerstersia [2-5] have been described.

We presented a case of COM by Kerstersia gyiorum, the third case described resistant to ciprofloxacin.

Case Presentation

The case is a male patient, 88 years old, with a history of type 2 diabetes mellitus, hypertension, dyslipidemia, chronic renal failure, chronic heart failure and prostatic hypertrophy. In 2004, he was diagnosed a right tympanic perforation and otorrhea with good clinical outcome after medical treatment.

In May 2016, the patient went to his family doctor complaining of a right otalgia and otorrhea for three weeks and being referred to an ENT specialist. Then, the presence of a foreign body (cotton) in the right ear canal and a tympanic perforation already known was shown. The foreign body was removed and topical corticosteroids (solution dipropionate/ clioquinol beclomethasone; Menaderm eardrops® 0.25 mg/10 mg/ml, 3 drops tid, 7 days) were prescribed and monthly reviews were scheduled.

After persistent otorrhea, two regimens of topical ciprofloxacin (Cetraxal ótico® 1.2 mg/0.4 ml solution ear drops, 3 drops tid, 7 days) are prescribed. So this torpid evolution the patient was again referred to an ENT specialist on July. After his physical exam, a profuse suppuration inside the right ear was observed and a sample of the exudate was taken for microbiological studies.

Direct Gram stain showed Gram-positive Cocci and Gramnegative Bacilli but no leukocytes. After incubation for 24 h, a few colonies of Staphylococcus aureus were isolated on Columbia agar (Oxoid, Germany) and Chocolate agar (Chocolate Agar Base, GC Medium, BD DifcoTM, Beckton Dickinson, US). In all media including MacConkey agar (No. 3, Oxoid, Germany), abundant slightly convex colonies with extended edges, colorful from gray hue to clear lavender (Figure 1), oxidase and catalase negative and indol positive were isolated. In the Gram stain from the grown colonies, gram-negative bacilli were observed and then identified by mass spectrometry using the technique of MALDI-TOF (matrixassisted laser desorption ionization time-of-flight) Biotyper 3.1 (Bruker Daltonic GmbH, Bremen, Germany) as Kerstersia gyiorum with a score of 2.1.


Figure 1 Growing colonies of Kerstesia over blood agar plate and MacConkey agar.

Antibiotic susceptibility test (Table 1) was performed by broth microdilution method using the automated system MicroScan WalkAway® (Siemens Healthcare, Spain currently Beckman Coulter) and the MicroScan® panels (Neg MIC Panel Type 44) were used. The interpretation of the minimum inhibitory concentration (MIC) was performed according to the breakpoints for non-Enterobacteriaceae gram-negative bacilli set by CLSI (Clinical and Laboratory Standards Institute) [6].

Antibiotic MIC (µg/mL) Interpretationa
Cefotaxime ≤ 1 S
Ceftazidime ≤ 1 S
Cefepima ≤ 1 S
Gentamicin ≤ 2 S
Tobramicin ≤ 4 S
Amikacin ≤ 8 S
Piperacilin-tazobactam ≤ 8 S
Trimetoprim-sulfametoxazol ≤ 2/38 S
Meropenem ≤ 1 S
Imipenem ≤ 1 S
Ciprofloxacin >2 R
Levofloxacin >4 R

Table 1 Antibiotic susceptibility profile.

Isolates were susceptible to cefotaxime ≤ 1 μg/ml, ceftazidime ≤ 1 μg/ml, cefepime ≤ 1 μg/ml gentamicin ≤ 2 μg/ml, tobramycin ≤ 2 μg/ml, amikacin ≤ 8 μg/ml, piperacillintazobactam ≤ 8 μg/ml tetracycline ≤ 4 μg/ml, trimethoprimsulfamethoxazole ≤ 2/38 g/ml, meropenem ≤ 1 μg/ml, imipenem ≤ 1 μg/ml and resistant to ciprofloxacin >2 μg/ml and levofloxacin >4 μg/ml.

K. gyiorum identification was confirmed by sequencing the 16S rRNA gene. The sequence was 99.8% identical to K. gyiorum type strain LMG …… using the NCBI 16S rRNA gene database.

After antibiotic susceptibility report was known, the patient was treated with topical gentamicin (gentamicin/ dexamethasone eye drops solution Colircusi Gentadexa® 1/3 / 0.5 mg, 3 drops tid) plus oral cloxacillin (cloxacillin 500 mg, 1 tablet tid) for 7 days. After that, a clinical improvement and otorrhea dry up was clearly observed.


Kerstersia genus belongs to the family Alcaligenaceae. It includes two kinds of species (Kerstersia gyiorum and Kerstersia similis). It is a gram-negative, small (1-2 μm), coccobacilli in pairs or short chains. It grows well on standard culture media between 28 and 42°C. On nutrient agar, the colonies are flat or slightly convex with smooth edges and white to light brown. They are strict aerobes, non- fermenter, catalase positive [7,8]. The biochemical features of our strain were similar to those reported in the literature.

K. gyiorum appears as a human pathogen described in the literature reviewed in nine occasions, being isolated from urine samples [9], ulcers [10,11] sputum [12] and causing chronic otitis in five cases [2-5].

The first isolation associated with chronic otitis was reported in 2012 by Almuzara et al. It was in a 16 years-oldmale patient diagnosed with chronic otitis media associated to cholesteatoma [2]. In the other cases K. gyiorum has been isolated together with other microorganisms, being difficult to determine its pathogenic role attributable solely to K. gyiorum (Table 2).

Reference Age Background Isolation in culture Ciprofloxacin
(MIC µg/mL)
Directed therapy Outcome
[2] 16 - AOM and retroauricular abscess
-Overcrowding and unhealthy conditions
Monomicrobial 1(S) Ceftriaxone 2 g iv then
Ciprofloxacin 500 mg bid po plus Amoxicilin/clavulanic, 1 g bid po
[3] 55 - Otorrhoea in childhood
-Bilateral mastoid surgery
Polymicrobial Corynebacterium amycolatum >32(R) Trimetoprim/sulfametoxazol Favourable
[4] 53 - Chronic otorrhea in adulthood
Polymicrobial Proteus mirabilis 1 (I) Topical ciprofloxacin Favourable
[4] 33 - Chronic otorrhea in adulthood Polymicrobial Staphylococcus aureus E. coli 1 (I) Topical ciprofloxacino Favourable
[5] 25 - Otorrhoea
In childhood
Polymicrobial Pseudomonas aeruginosa >2 (R) Imipenem 500 mg/qid iv,
10 days
Present Case 88 - Chronic otorrhea in adulthood
- Tympanum drilling
Staphylococcus aureus
>2 (R) Topical gentamicin
Cloxacilin po 500 mg tid
7 days

Table 2 Summary of reported cases of chronic otitis media caused by K. gyioruma.

In our case, Staphylococcus aureus was also isolated however we considered Kerstersia gyiorum as a true pathogen in view of the chronicity of the disease, the poor response to treatment with ciprofloxacin, the observation of bacilli in the Gram stain and, the abundant growth into the inoculated plates. The cases reported so far in literature, were patients with chronic ear disease, as our patient, so it is deductible K. gyiorum has a pathogenic role in these patients. In our case there was no history of smoking or overcrowded conditions, described by other authors [2-4].

Currently, the identification of new species by MALDI-TOF and 16S rRNA sequencing are essential for microbiological diagnosis.

There are no cutoffs of antibiotic susceptibility in CLSI or EUCAST (European Committee on Antimicrobial Susceptibility Testing) specific to this genus. We used the CLSI criteria for non-Enterobacteriaceae.

According to Harris et al. [13] about the use of quinolones and aminoglycosides in the treatment of chronic suppurative otitis media, quinolones are bactericidal allowing different routes of administration and therefore outpatient treatments. They also are less ototoxic than aminoglycosides and have the same efficacy in resolving otorrhea all of which makes them a first-line option in chronic otitis, especially in cases with tympanic perforation.

Kerstersia isolates are generally susceptible to ciprofloxacin and cefotaxime [8] although recently there have been described two strains resistant to ciprofloxacin [3,5]. Treatment failure is considered when otorrhea persists approximately three weeks after medical therapy. Causes of failure include the presence of resistant microorganisms, the presence of cholesteatoma or a poor adherence to treatment, being therefore necessary a microbiological analysis including an antibiotic susceptibility study [14].

Our case would be the third case resistant to ciprofloxacin reported in the literature. The prior long treatment with ciprofloxacin may be the clue of further selection of resistant strains.

In summary, K. gyiorum is therefore a novel pathogen to be considered in the differential diagnosis of microorganisms causing chronic otitis media.

Microbiological diagnosis is the important key to guide the antimicrobial treatment because of the lack of homogeneity in its antibiotic susceptibility.

Conflict of Interest

The authors declare not to have an association that might pose a conflict of interest.

There is no fund, non-financial support received by the authors of the manuscript.


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