Bacteriological Profile of Chronic Suppurative Otitis Media and Antibiotic Susceptibility in a Tertiary Care Hospital in Shanghai, China

Anaerobic bacteria dominate the cholesteatoma tissue of chronic suppurative otitis media patients

The aim of this study was to investigate both the microbial composition and absolute abundance of clinically relevant bacteria in tissue specimens from patients with chronic suppurative otitis media with cholesteatoma (CSOM with cholesteatoma). Mastoid mucosa and cholesteatoma tissue from eleven subjects with CSOM with cholesteatoma, and mastoid mucosa from ten controls were examined using standard hospital culture swabs, Gram staining, bacterial 16S rRNA gene sequencing, Droplet Digital PCR (ddPCR), and multiplex PCR. Positive results from culture swabs were reported in half the CSOM with cholesteatoma samples and 1 control sample. In contrast, ddPCR detected bacterial genes copies in all 11 mucosa and cholesteatoma of CSOM subjects and 3 control samples. The average bacterial gene copies in tissue samples with CSOM with cholesteaotoma (1.6 ± 0.7 log10) was significantly higher compared to healthy controls (0.3 ± 1.6). These results were corroborated with Gram-staining that identified the large presence of Gram-positive cocci cells in the cholesteatoma tissue of CSOM subjects which were not seen in the mucosa of controls. The most abundant genus detected by sequencing in the mucosa and cholesteatoma of CSOM samples was Anaerococcus (93.5% of all reads), and genus Meiothermus (0.9%) in the control sample. The 3 samples with the highest sequencing reads (>300) were further analysed using multiplex PCR to identify the dominant Anaerococcus species. Anaerococcus hydrogenalis was the dominant species identified in these samples. In contract, commonly named ear pathogens, genera Staphylococcus and Pseudomonas, were detected in low numbers (<0.001% of all sequencing reads) and low prevalence (2/16 samples) in the tissue samples of this study. The results show that culture severely underestimated the bacterial diversity in CSOM samples and investigating tissue rather than standard culture swabs might be advantageous to understanding the disease process. The high abundance of bacteria and the large presence of Gram-positive cells detected in the cholesteatoma tissue of CSOM compared to mucosa of CSOM or controls could be members from the genus Anaerococcus. Anaerococcus may well be a pathogen in CSOM with cholesteatoma, but their role in this condition requires further investigation.

Gram-negative Bacteria are Associated With Sensorineural Hearing Loss in Chronic Otitis Media

OBJECT

Chronic otitis media (COM) is an inflammatory disease that commonly presents with otorrhea and hearing loss. Bacteria-induced inflammation can cause inner ear damage, leading to sensorineural hearing loss (SNHL). This study aimed to compare the prevalence and severity of SNHL in patients with gram-negative versus gram-positive cultures and examine associations between the concentrations of circulating monocytes and neutrophils with bacteria species and SNHL.

METHODS

This was a retrospective study. Cholesteatoma or chronic suppurative otitis media patients with otorrhea were enrolled. Middle ear secretions were collected using sterile swabs under an otoscope, and sent for bacterial detection within 30 min. Pure tone audiometry and circulating leukocyte counts were recorded and analyzed in patients infected with different pathogens. Logistic regression analysis was used to identify the risk factors associated with SNHL.

RESULTS

A total of 137 patients were enrolled, including 45 patients infected with gram-negative bacteria, 41 with gram-positive bacteria, 20 with polymicrobial infection, and 31 with no bacterial growth. Logistic regression analysis showed that bacterial culture positive infections (OR = 7.265, 95% CI 2.219-23.786, p = 0.001) were an independent risk factor for SNHL. Patients with gram-negative bacteria had higher risks of SNHL (p < 0.0001) and more severe hearing loss (p = 0.005) than those with gram-positive bacteria. COM patients infected with gram-negative bacteria showed an increase in circulating monocytes, which correlated with the occurrence of SNHL (p = 0.0343).

CONCLUSION

Gram-negative bacteria are associated with elevated circulating monocyte counts and have a higher risk of severe SNHL.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:3335-3341, 2024.

Etiology, Microbiological Isolates, and Antibiotic Susceptibilities in Inpatients with Refractory Auricular Perichondritis: A 10-Year Retrospective Study

Purpose

This study aimed to elucidate the etiologies, microbiological profiles, antibiotic susceptibilities of bacteria and outcomes of patients with auricular perichondritis.

Patients and Methods

This was a single-center retrospective study. Inpatients diagnosed with auricular perichondritis at a university teaching hospital in eastern China between January 2013 and December 2022 were included in this study.

Results

A total of 127 patients were enrolled, with an average age of 50.6 ± 16.9 years. In addition to cases in which the etiology remained undetermined in 37% of the patients, postoperative infection emerged as the predominant cause (37.8%), followed by trauma (18.1%). Among the 61 cultured isolates, 21.3% were gram-positive bacteria, 55.7% were gram-negative bacteria, and 23.0% were fungal isolates. The most frequent isolate was Pseudomonas aeruginosa (30/61, 49.2%). Notably, the incidence of fungal infections was markedly higher among postoperative patients than among post-traumatic patients (41.7% vs 7.1%, p = 0.03). The proportions of gram-negative bacteria (60.0% vs 50.0%) and fungal isolates (28.6% vs 15.4%) exhibited an increasing trend during the period of 2018-2022, as compared to the previous period of 2013-2017. The bacterial isolates exhibited high susceptibility to vancomycin (100%), amikacin (100%), cefepime (94.6%), and ceftazidime (90.9%). In contrast, overall susceptibility to fluoroquinolones was relatively low (65.2-67.4%), demonstrating a declining trend in the susceptibility of Pseudomonas aeruginosa. Notably, 78.7% of the patients received an initial treatment regimen covering Pseudomonas aeruginosa. Within 30 days of discharge, 8.5% (6/71) experienced an infection recurrence.

Conclusion

Auricular perichondritis predominantly originates from iatrogenic (postoperative) infections. Antibiotic therapy covering Pseudomonas aeruginosa is a sensible and appropriate empirical treatment in the majority of patients with auricular perichondritis. However, increased resistance to fluoroquinolones has become a notable concern, suggesting the need to seek new, more aggressive strategies.

Bacteriology and trends of antimicrobial resistance of Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus in otitis media: A retrospective data analysis

OBJECTIVES

Otitis media (OM) has a high prevalence worldwide and the treatment is crucial because hearing loss in children can lead to growth disorders such as language development disorders. The aim of this study is to analyse the changes in bacterial strains and the trends of antibiotic susceptibility in otitis media with effusion (OME), chronic otitis media (COM) and cholesteatomatous otitis media (Chole OM).

DESIGN

This retrospective study involved 2926 patients diagnosed with OME, COM, or Chole OM between January 2000 and December 2020. The clinical data were collected and analysed through chart review from May 2021 to July 2021.

SETTING

Two tertiary medical centres.

PARTICIPANTS

The 2926 OM patients.

MAIN OUTCOMES AND MEASURES

An otorrhea sample was collected on the first day of their hospital visit. Middle ear fluid samples for bacterial culture and antibiotics susceptibility test were collected from patients during middle ear surgery, including ventilation tube insertion. In each type of OM, the distribution of bacterial strains in the 2000s and the 2010s was compared. In addition, changes in the detection rate of methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (PA) and trends in their antibiotic susceptibility over the last 10 years were analysed.

RESULTS

The most frequently detected bacterial strains in OME, COM and Chole OM over the study period were coagulase-negative Staphylococcus (CNS) (29.6%), MRSA (24.1%), and PA (20.1%). Compared to the 2000s, the proportion of non-typable Haemophilus influenzae in OME and MRSA in COM increased in the 2010s (27.4%-31.6% and 1.5%-29.5%, respectively). In total three types of OM, although there was no significant trend of change in detection rates of MRSA, PA, and multidrug resistant-P. aeruginosa (MDR-PA) during the last 10 years, resistance to the Quinolone class of MRSA and PA tended to increase (P < .05).

CONCLUSIONS

The composition of bacterial strains in each types of OM has changed over the past 20 years. Additionally, the antibiotic resistance of MRSA and PA has increased in the last decade. Therefore, when using empirical antibiotics in necessary situations, it is necessary to change to an appropriate antibiotic through a bacterial culture test and antimicrobial susceptibility test.

Antimicrobial Resistance and Virulence Gene Profile of Clinical Staphylococcus aureus: A Multi-Center Study from Ethiopia

Background

Staphylococcus aureus causes a wide range of infections from mild skin and soft tissue to severe life-threatening bacteremia. The pathogenicity of S. aureus infections is related to various bacterial surface components and extracellular proteins such as toxic-shock syndrome (TSS) toxin and Panton-Valentine leukocidin (PVL). In this study we determine the antimicrobial resistance of isolated strains and their virulence genes in Ethiopia.

Methods

A total of 190 archived S. aureus isolates from four Ethiopia Antimicrobial Resistance (AMR) Surveillance sites were analyzed. The identification of S. aureus was done by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF Biotyper) and antimicrobial susceptibility test (AST) was done using VITEK^® 2. Multiplex PCR was used to detect mecA, mecC, pvl and spa genes and super-antigens (sea, seb, sec, seh and sej staphylococcal enterotoxins).

Results

A total of 172 isolates were confirmed as S. aureus, 9 (5.23%) were methicillin-resistant S. aureus (MRSA) and 163 (94.76%) were methicillin-susceptible S. aureus (MSSA). AST showed that 152 (88.4%) isolates were resistant to penicillin; 90 (52.32%) resistant to trimethoprim-sulfamethoxazole; and 45 (26.16%) resistant to tetracycline. A total of 66 (38.37%) isolates harbored at least one staphylococcal enterotoxin gene and 31 (46.96%) isolates had more than one. The most frequent enterotoxin gene encountered was seb 28 (16.28%). The TSST-1 gene was detected in 23 (13.37%). Presence of staphylococcal enterotoxin gene showed significant association with antibiotic resistance to cefoxitin, benzylpenicillin, oxacillin, erythromycin, clindamycin, tetracycline and SXT. The pvl gene was detected in 102 (59.3%) of isolates. Isolates from patients below 15 years of age showed significantly high numbers of pvl gene (P = 0.02). Presence of sej (P = 0.011) and TSST-1 (P <0.001) genes were associated with the presence of pvl gene.

Conclusion

In this study, isolates were highly resistant to oral antibiotics and the pvl, seb, sea and TSST-1 genes were prevalent.

Bacterial diversity of middle ear cholesteatoma by 16S rRNA gene sequencing in China

In this study, the bacterial diversity of acquired middle ear cholesteatoma (MEC) was evaluated to reveal its pathogenesis and provides a guide for the use of antibiotics. Twenty-nine cases of acquired MEC and eight cases of healthy middle ears undergoing cochlear implantation (CI) were evaluated. Full-length 16S rRNA gene sequencing was performed to profile the bacterial communities in lesions and healthy tissues of the middle ear. ACE (P = 0.043) and Chao1 (P = 0.039) indices showed significant differences in alpha diversity (P < 0.05). Analysis of PERMANOVA/Anosim using the Bray-Curtis distance matrix results suggested that the between-group differences were greater than the within-group differences (R = 0.238, P < 0.05, R² = 0.066, P < 0.05). Bacterial community analysis revealed that Alphaproteobacteria at the class level and Caulobacterales and Sphingomonadales at the order level were significantly different (P < 0.05). In the LefSe (Linear discriminant analysis effect size) analysis, Porphyromonas bennonis was elevated, and Bryum argenteum and unclassified Cyanobacteriales were reduced at the species level in MEC (P < 0.05). Fifteen metabolic pathways were found to be significantly different between the two groups by analysing the abundance of metabolic pathways in level 2 of the Kyoto Encyclopaedia of Genes and Genomes (KEGG). Seven and eight metabolic pathways were significantly elevated in the MEC and control groups, respectively (P < 0.05). The role of bacteria in the pathogenesis of acquired MEC was further refined through analysis of metabolic pathways. These findings indicate that the acquired MEC and healthy middle ear contain more diverse microbial communities than previously thought.

[Bacterial microbiota in exacerbation of chronic purulent otitis media in children]

OBJECTIVE

To study current spectrum of bacterial pathogens that cause exacerbation of chronic suppurative otitis media (CSOM) in children, who live in Moscow region, and to investigate sensitivity of isolated strains to various antibacterial drugs.

MATERIAL AND METHODS

The results of microbiome's bacterial cultivation of purulent discharge from tympanic cavities collected from 269 children with CSOM aged from 1.5 to 18 years for the period from 2017 to 2021 yr. were analyzed. The majority of examined subjects (70.6% from 190 children) had CSOM with cholesteatoma.

RESULTS

Monoculture was received in 62.5% of examined patients, bacterial associations - in 25.7%, bacterial-fungal associations - in 2.6%, and there was no growth in 9.2% of subjects. Staphylococcus aureus, which was found in 36.1% of children, dominated among agents. Pseudomonas aeruginosa was the second most frequently diagnosed agent, revealed in 12.3% of patients. Candida spp. (7.1%) was prevalent in bacterial-fungal associations. The article presents the results of isolated strains' sensitivity to antibacterial drugs. The high resistance to oxacillin, cefoxitin and antipseudomonal drugs was found among strains collected from children with CSOM and cholesteatoma.

CONCLUSION

S. aureus (36.1%) and P. aeruginosa (12.3%) remain the most common causative agents for exacerbation of chronic suppurative otitis media in children. Pathogenic fungi are not isolated separately, and Candida spp. (6.7%) dominates in bacterial-fungal associations. It is generally recognized and confirmed by our research, that topical fluoruquinolones (ciprofloxacin) are the most effective drugs for exacerbation of chronic suppurative otitis media treatment. Systemic antibiotics, of which fluoruquinolones (ciprofloxacin) are the most effective, are recommended in severe exacerbation, severe and destructive forms of chronic suppurative otitis media.

Definite therapy of mixed infection alleviates refractory dilemma of adult chronic suppurative otitis media

The characteristics, risk factors, microbial distributions and effective treatment regimens for Chronic suppurative otitis media (CSOM) patients intractable to empirical therapy were analyzed. Adult CSOM patients of China Medical University Hospital from 2018 to 2020 were included. Subjects of refractory and non-refractory groups were investigated for characteristics of age, sex, nation, comorbidities, otomycosis, and associated complications. Risk factors, microbiology distributions, and treatment regimens were analyzed. Twenty-six refractory patients (55.0 ± 17.7 years) and 66 non-refractory patients (54.1 ± 13.7 years) were studied. A significantly higher rate of otomycosis and CSOM complications was observed in refractory group than in non-refractory one (73.1% vs. 36.4%; p = 0.002; 57.7% vs. 10.6%, p < 0.001, respectively). Multivariate analysis revealed atopic diathesis (p = 0.048), otomycosis (p = 0.003) and CSOM complications (p < 0.001) were risk factors of refractory CSOM. Coagulase-negative staphylococci (CoNS) and methicillin-resistant Staphylococcus aureus (MRSA) were the prevailing pathogens. Patients of refractory group tented to have higher rates of mixed infection (42.9%% vs. 23.7%) and significantly more included fungal pathogen (19.0% vs. 2.6%; p = 0.049) than those of non-refractory cohort. Topical treatment of fungus significantly improved outcome of refractory CSOM. Atopic diathesis, otomycosis, and CSOM-associated complications were risk factors of refractory CSOM. Systemic and local treatment to possible drug-resistant pathogens, likely CoNS and fungus, possible improves recalcitrant CSOM. Correspondingly, early identification of CSOM complications, routine culture and susceptibility testing and treatment of resistant bacteria and fungus are key elements to the successful management of adult CSOM.

Sıçanlarda pseudomonas aeruginosa ile indüklenen kronik otitis media modelinde borik asit tedavisinin etkinliği

Amaç: Kronik otitis media (KOM), bakteriyel veya viral patojenlerin neden olduğu orta kulağın sık görülen enfeksiyöz hastalıklarından biridir. Bu çalışmanın amacı, sıçanlarda Pseudomonas aeruginosa (P. aeruginosa) ile indüklenen KOM modelinde topikal %4’lük ve %8’lik borik asit (BA) uygulamasını sistemik siprofloksasin ile karşılaştırarak KOM tedavisinde borik asidin etkinliğini araştırmaktır. Gereç ve Yöntem: 42 Sprague Dawley cinsi sıçan 7 eşit gruba ayrıldı. P. aeruginosa ile KOM modeli oluşturuldu. Kontrol grubu, KOM grubu, topikal %4’lük ve %8’lik BA tedavi grubu, sistemik siprofloksasin tedavi grubu ve topikal %4’lük ve %8’lik BA temas grubu arasında klinik, histopatolojik ve immünohistokimyasal karşılaştırmalar yapıldı. Bulgular: KOM modelinde %4’lük BA uygulaması ile orta derecede ödem, enflamasyon, dejenerasyon ve orta derecede tümör nekroz faktör-alfa (TNF-α) ekspresyonu tespit edildi. %8’lik BA uygulaması ile hafif ödem, inflamasyon, dejenerasyon ve hafif TNF-α ekspresyonu tespit edildi. Sonuç: %4’lük ve %8’lik BA tedavisinin önemli klinik, histopatolojik ve immünohistokimyasal iyileşme sağladığı görüldü. %8’lik BA uygulamasının daha yüksek tedavi etkinliğine sahip olduğu ve orta kulak mukozasına zararlı bir etkisinin olmadığı gösterildi.

Microbiota Associated With Cholesteatoma Tissue in Chronic Suppurative Otitis Media

Otitis media (OM), defined as infection or inflammation of the middle ear (ME), remains a major public health problem worldwide. Cholesteatoma is a non-cancerous, cyst-like lesion in the ME that may be acquired due to chronic OM and cause disabling complications. Surgery is required for treatment, with high rates of recurrence. Current antibiotic treatments have been largely targeted to previous culturable bacteria, which may lead to antibiotic resistance or treatment failures. For this study, our goal was to determine the microbiota of cholesteatoma tissue in comparison with other ME tissues in patients with long-standing chronic OM. ME samples including cholesteatoma, granulation tissue, ME mucosa and discharge were collected from patients undergoing tympanomastoidectomy surgery for chronic OM. Bacteria were profiled by 16S rRNA gene sequencing in 103 ME samples from 53 patients. Respiratory viruses were also screened in 115 specimens from 45 patients. Differences in bacterial profiles (beta-diversity) and the relative abundances of individual taxa were observed between cholesteatoma and ME sample-types. Additionally, patient age was associated with differences in overall microbiota composition while numerous individual taxa were differentially abundant across age quartiles. No viruses were identified in screened ME samples. Biodiversity was moderately lower in cholesteatoma and ME discharge compared to ME mucosal tissues. We also present overall bacterial profiles of ME tissues by sample-type, age, cholesteatoma diagnosis and quinolone use, including prevalent bacterial taxa. Our findings will be useful for fine-tuning treatment protocols for cholesteatoma and chronic OM in settings with limited health care resources.

Chronic Suppurative Otitis Media Characteristic in Secondary Hospital in Yogyakarta

BACKGROUND: Chronic suppurative otitis media (CSOM) is the most common ear infection that causes hearing loss and affects the quality of life worldwide. AIM: The study aimed to describe the risk factor of CSOM patients at a private hospital in Yogyakarta, Indonesia, from March to June 2021. METHODS: This study was an observational analytical study with a case–control design. The respondents were 55 patients with CSOM who met inclusion criteria and 56 respondents as controls. A checklist interview was conducted to determine the present and past history of diseases, and the relationship among potential risk factors was analyzed using bivariate analysis. A bivariate analysis was used to specify the odds ratios, 95% confidence intervals, and the relationship between risk factors and the incidence of CSMO. RESULTS: The characteristic cases were as follows: Majority age over 20 years, 56% male, 47% university degree, 29% history of allergy, 25% history of acute respiratory infection, 56% complain of discharge from the ear, 31% snoring, 67% cigarette consumption, 42% earn 2–5 million rupiahs per month, and 73% of their homes are closed to health-care facilities. Four risk factors for CSOM omit this included: Education, medical history from the ear, snoring, and income per month (p < 0.05). CONCLUSION: According to the results, the majority of CSOM patients to be treated at a private clinic in Yogyakarta were male at productive age, had university education, had no history of allergies and acute respiratory infections, and had a history of secrete from the ear, exposure to cigarettes, and median income per month.

Identification and Antifungal Susceptibility Analysis of Stephanoascus ciferrii Complex Species Isolated From Patients With Chronic Suppurative Otitis Media

Background

Stephanoascus ciferrii is a heterothallic ascomycetous yeast-like fungus. Recently, the concept of S. ciferrii complex has been proposed and it consists of S. ciferrii, Candida allociferrii, and Candida mucifera. We aimed to identify 32 strains of S. ciferrii complex isolated from patients with chronic suppurative otitis media (CSOM) at the species level and analyze the morphology and antifungal susceptibility profiles of the three species.

Method

The sequencing of the internal transcribed spacer (ITS) region and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) were used to identify S. ciferrii complex species. The SARAMIS software was used for cluster analysis of the mass spectra. All the strains were cultured on Sabouraud dextrose agar (SDA) and CHROM plates for 7 days. In the meantime, colonies of the 32 strains went through Gram staining. The Sensititre YeastOne YO10 colorimetric panel was used for the antifungal susceptibility analysis.

Results

There were 10 strains of C. allociferrii (31.25%), six strains of C. mucifera (18.75%), and 16 strains of S. ciferrii (50%) in the 32 strains of S. ciferrii complex according to the sequencing of the ITS region. MALDI-TOF MS could identify S. ciferrii but showed no results for C. allociferrii and C. mucifera. The cluster analysis of the mass spectra by SARAMIS indicated that the MALDI-TOF MS could distinguish the three species. The morphology characteristics of the three species were similar. As for antifungal susceptibility, S. ciferrii and C. mucifera tended to have high fluconazole MICs compared with C. allociferrii. C. mucifera and C. allociferrii had relatively low flucytosine MICs while S. ciferrii owned high flucytosine MICs. Besides, C. mucifera tended to have a higher MIC value than S. ciferrii for amphotericin B and C. allociferrii for anidulafungin, micafungin, and caspofungin.

Conclusion

The antifungal susceptibility profiles of the three species of S. ciferrii complex had their own characteristics. Besides, more mass spectra of C. allociferrii and C. mucifera are needed to construct the reference database for S. ciferrii complex species, enabling MALDI-TOF MS to identify S. ciferrii complex at species level.

Profile of aerobic bacteria and their antibiotic sensitivity in chronic suppurative otitis media in Al-Ramadi Teaching Hospital, Ramadi City, Iraq

BACKGROUND

Chronic suppurative otitis media (CSOM) is a common otological problem in daily clinical practice. It is crucial to know the bacterial pathogens and their antimicrobial susceptibilities in patients with CSOM to achieve a good clinical outcome.

OBJECTIVES

To identify the aerobic bacterial pathogens and their antibiotic sensitivities in subjects with CSOM in Al-Ramadi Teaching Hospital.

MATERIALS AND METHODS

A cross-sectional, descriptive study included 102 subjects with a clinical diagnosis of CSOM (aural discharge >2 weeks, eardrum perforation, and conductive deafness). Purulent discharge was obtained from the middle ear with sterile swabs and cultured for bacterial microorganisms. The sensitivity of the isolated agents to antimicrobials was evaluated by a culture and sensitivity method. SPSS version 22 was used for statistical analysis of the data. Differences were considered statistically significant at p < 0.05.

RESULTS

Out of 3634 outpatient subjects, 102 (2.8%) presented with active CSOM. The age range of the patients was 1-70 years (mean 28.90 ± 19.8). There were 58 females (56.9%). Out of 117 ear swab specimens, 107 (91.5%) yielded positive cultures. The majority (101, 94.4%) of the specimens yielded a single organism. There was a high statistically significant difference (p < 0.001) between gram-positive (n = 77, 68.1%) and gram-negative pathogens (n = 36, 31.9%). Pseudomonas aeruginosa in 65 (57.5%) cases and Staphylococcus aureus in 19 (16.8%) cases were the two most commonly isolated organisms. The drugs imipenem (93.8%), amikacin (86.1%), azteronam (83.1%), and ciprofloxacin (81.5%) were effective against P. aeruginosa (p < 0.001). Amikacin (100%), imipenem (94.7%), ciprofloxacin (68.4%), and gentamicin (63.1%) were the most effective antibiotics against Staph. aureus (p < 0.001).

CONCLUSION

The prevalence rate of active CSOM was 2.8%. Ciprofloxacin showed high effectiveness against the two most common isolated pathogens (P. aeruginosa and Staph. aureus); therefore, it could be used as empirical therapy for active CSOM cases.