Outer Ear Infections in Iran: A Review

Phenotypic and genotypic characterization of Staphylococcus aureus strains isolated from otitis externa: Emergence of CC30-spa t019-SCCmec IV carrying PVL as major genotype

The increasing emergence of Staphylococcus aureus as the primary causative agent of otitis externa has been noted; however, detailed information regarding the molecular characteristics of these strains in Iran remains scarce. The current study aims to investigate both genotypic and phenotypic attributes of S. aureus strains implicated in ear infections. In the present work, we analyzed 60 S. aureus strains isolated from cases of otitis externa over a period of 45 months. The resistance patterns were determined using disk diffusion and microbroth dilution methods. All S. aureus isolates were confirmed by the nucA polymerase chain reaction assay, and their biofilm production was assessed by a microtiter plate assay. Molecular characterization of the isolates was performed using the staphylococcal cassette chromosome mec, multilocus sequence typing, and staphylococcus protein A typing methods. Overall, the results indicated that 44 out of 60 S. aureus isolates (73.3 %) were methicillin-resistant Staphylococcus aureus. Resistance to mupirocin and vancomycin was observed in 13.3 % and 1.7 % of the tested isolates, respectively. Furthermore, out of the 60 S. aureus isolates, 56 strains (93.4 %) were classified as positive biofilm strains at different levels. Twelve distinct clonal lineages were identified. The vast majority of S. aureus isolates belonged to CC30/ST30-MRSA IV/t019 (41.7 %). Among the 31 strong biofilm producers, the majority (64.5 %) belonged to CC30/ST30-MRSA IV/t019 clone. Biofilm negative isolates belonged to CC22/ST22 (2 isolates), CC8/ST585 (one isolate), and CC8/ST8 (one isolate). Our result revealed that about three-quarters of PVL-positive strains belonged to CC30/ST30. Our data confirmed the presence of MSSA strains among CC30/ST30 and CC22/ST22 isolates. The mupirocin resistant isolates (n = 8) belonged to CC8/ST585-MRSA III/t713 (37.5 %), CC8/ST239-MRSA III/t030 (25 %), CC8/ST8-MRSA IV/t008 (12.5 %), CC8/ST239-MRSA III/t037 (12.5 %), and CC22/ST22-MRSA IV/t790 (12.5 %) lineages. The VRSA strain belonged to the CC8/ST8-MRSA IV/t008 lineage, carrying the vanA determinant. iMLSB phenotypes (n = 14) were distributed across different lineages, including CC30/ST30-MRSA IV/t019 (21.5 %), CC30/ST30-MSSA/t021 (21.5 %), CC22/ST22-MSSA/t005 (14.3 %), CC8/ST239-MRSA III/t030 (14.3 %), CC22/ST22-MSSA/t1869 (7.1 %), CC22/ST22-MRSA IV/t790 (7.1 %), CC8/ST239-MRSA III/t037 (7.1 %), and CC1/ST772-MRSA IV/t10795 (7.1 %). These findings highlight significant genotypic diversity and high biofilm formation among our isolates. The frequent occurrence of the CC/ST30 clone in S. aureus strains isolated from otitis externa reflects the emergence of these lineages as a predominant clone in Iran, posing a significant public health concern.

Aetiology of ear infection and antimicrobial susceptibility pattern among patients attending otorhinolaryngology clinic at a tertiary hospital in Dar es Salaam, Tanzania: a hospital-based cross-sectional study

OBJECTIVES

To determine the aetiological pathogens causing ear infections and their antimicrobial susceptibility patterns among patients with ear complaints at a tertiary hospital in Dar es Salaam.

DESIGN

Hospital-based cross-sectional study.

SETTINGS

Otorhinolaryngology clinic at Muhimbili National Hospital, Dar es Salaam, Tanzania.

PARTICIPANTS

Patients presenting with signs and symptoms of ear infection.

MAIN OUTCOME MEASURE

Bacteria and fungi isolated from ear swab specimens of patients presenting with signs and symptoms of ear infection; and antimicrobial susceptibility patterns of isolated bacteria.

RESULTS

Two hundred and fifty-five participants were enrolled, with a median age of 31 years and an IQR of 15-49. Otitis externa was the predominant type of ear infection, accounting for 45.1%. We observed positive bacteria culture in 53.3% of study participants, in which 41% of isolates were obtained from patients with chronic suppurative otitis media. Moreover, Staphylococcus aureus (27.3%) and Pseudomonas aeruginosa (24.2%) were the most frequently isolated bacteria, while Candida spp, 12 (63.8%) and Aspergillus spp, 9 (36.2%) were the only isolated fungi. Furthermore, we report that 93% of isolated Enterobacterales were resistant to amoxicillin/clavulanic acid, and 73% were resistant to ceftazidime. In addition, we detected 34.4% extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-PE) and 44.4% methicillin-resistance S. aureus (MRSA). We also found that 22% of the bacteria isolates were resistant to ciprofloxacin, a primary topical antibiotic used in managing ear infections.

CONCLUSIONS

The findings from this study reveal that the leading aetiological agent of ear infection is bacteria. Furthermore, our findings show a significant proportion of ESBL-PE and MRSA-causing ear infections. Hence, detecting multidrug-resistant bacteria is crucial to improving ear infection management.

Numerical Simulation of Aspergillus Niger Spore Deposition in Nasal Cavities of a Population in Northwest China

Background: As common pathogens in the human respiratory tract, fungal-spore-related health risks have been challenging to evaluate properly. This paper presents numerical simulations of particle deposition of Aspergillus niger spores in human nasal cavities. Methods: 30 healthy adults (including 60 nasal chambers) who lived in northwest China were recruited to conduct a nasal cavity numerical simulation using computational fluid dynamics–discrete phase model (CFD-DPM). The deposition rate in each anatomic area and its influencing variables, such as body position and respiratory flow rate, were analyzed. Results: (1) Under a resting condition, only about 5.57% ± 1.51% Aspergillus niger spores were deposited in the nasal cavity, while most of them escaped from the nasopharynx, and 0.31% ± 0.20% spores entered the maxillary sinus; (2) under an exercising condition, spores deposited in the nasal cavity were about 2.09 times as many as that in the resting state; (3) in a lying position, the A. niger spores deposited evenly on the lateral wall of the nasal cavity and the sinus when compared with a standing position. However, the deposition rate in each anatomic area did not change significantly.

A Comparison of Antifungal Drugs and Traditional Antiseptic Medication for Otomycosis Treatment: A Systematic Review and Meta-Analysis

Objectives/Hypothesis: To perform a systematic review and meta-analysis to compare the efficacy of and complications associated with antifungal drugs and traditional antiseptic medication for the treatment of otomycosis.

Data Sources: The PubMed, EMBASE, GeenMedical, Cochrane Library, CBM, CNKI, VIP and other databases were searched from January 1991 to January 2021.

Methods: The systematic literature review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Randomized controlled trials (RCTs) and non-randomized studies (case-control, cohort, and case series) were included to assess the topical use of antifungal drugs and traditional antiseptic medication in patients with otomycosis. The research subjects were patients who were clinically diagnosed with otomycosis and whose external auditory canal secretions were positive for fungi. Funnel plots were used to detect bias, and the Q test was used to assess heterogeneity. The random-effects model was used for meta-analysis. The t-test was used to assess significance.

Results: Of the 324 non-duplicate studies screened, 16 studies met the criteria for full-text review, and 7 were included in the meta-analysis. Four studies reported recovery conditions (P = 0.01). Six common complications after medication use were compared, and there were no significant differences. The authors further conducted subgroup analysis according to complications. The differences in the rates of ear distension (P = 0.007), earache (P = 0.03) and tinnitus (P = 0.003) were statistically significant.

Conclusion: The results of this meta-analysis and literature review showed that antifungal drugs and traditional antiseptic medication were effective in relieving symptoms in patients with otomycosis, and the two treatments were associated with different complications. Otolaryngologists have the option to use one medication or a combination of two drugs on the basis of the condition. Future research in this area should include RCTs with long-term follow-up to guide the development of otomycosis guidelines to overcome some of the weaknesses found in the literature.

Systematic Review Registration:https://www.crd.york.ac.uk/PROSPERO/#myprospero.

Molecular Diversity of Aspergilli in Two Iranian Hospitals

The Aspergillus species are main causative agents of various infections such as invasive aspergillosis (IA) in immunocompromised patients and these infections have high mortality rates. In this study, we provide insight in the species causing aspergillosis in Iran based on morphology and sequence data. Clinical (n = 117) and environmental isolates (n = 54) collected during 2010-2016 from University hospitals in Mashhad and Tehran (Iran) were identified both morphologically and molecularly using partial calmodulin (CaM) gene sequences. Clinical cases were identified based on EORTC/MSG criteria. Aspergillus flavus (n = 96, 55%) was the most prevalent species among the clinical and environmental isolates while A. fumigatus (n = 13, 7.5%) ranked fourth after A. tubingensis (n = 23, 13%) and A. welwitchiae (n = 18, 10%). Species such as A. tubingensis, A. welwitschiae, A. fumigatus, A. sydowii, A. neoniger and A. terreus were present in both clinical and environmental samples indicating the possible environmental source of infections. Interestingly, A. niger was isolated only once. Furthermore, 13 other rare and cryptic Aspergillus species were detected. Pulmonary and respiratory disorders (n = 33), followed by transplantation (n = 23), invasive fungal rhinosinusitis (n = 14), and haematological malignancies (n = 12) were major predisposing factors. According to EORTC/MSG criteria, there were 43 probable cases identified followed by 36 cases for each of proven and possible ones. Correct molecular identification will be useful for further epidemiological studies.

Role of Clotrimazole in Prevention of Recurrent Otomycosis

Otomycosis is one of the relatively common diseases in the world which is caused by different fungi especially saprophytes. Concerning the relapse of this disease in a number of individuals, the present study was performed to evaluate the inhibitory effect of clotrimazole drop in the relapse of otomycosis. Clinical samples were taken by an ENT specialist from patients suspicious of having otomycosis. A part of these samples were stained, and others were cultured. The diagnosis of otomycosis was made on the basis of the recognizable and characteristic appearance of fungal hyphae or mycelium and fruiting bodies and/or conidiophores under microscopic examination. Patients with suspected otomycosis are not at risk of recurrence after treatment with clotrimazole drops. Out of the 161 individuals in whom definite diagnosis of otomycosis was made, the most affected individuals were, in the age range of 40–49 years, women, urban citizens, and housewives. Pruritus and diminished hearing were the main complaints of the patients. Aspergillus niger and A. flavus as well as Candida albicans were the main causes of the disease. The relapse of disease was observed in only five patients (3.1%), where A. niger was the main fungus. Most relapses were observed in women and in those with diminished hearing, manipulating the ears, ulcers in the canal, and tympanum. Our results suggested that usage of clotrimazole can be effective in reducing the relapse of otomycosis, and concerning the high cost of treating otomycosis while the low cost of using clotrimazole, usage of this drop is recommended to reduce the relapse of otomycosis.