High rate of early recurrence of peritonsillar abscess among adolescents and young adults.

BACKGROUND: Peritonsillar abscess (PTA) can be treated with aspiration or incision for drainage, but a subsequent PTA can occur if tonsillectomy is not performed. Better understanding is needed of when tonsillectomy should be performed to avoid PTA recurrence. OBJECTIVE: This study investigated the recurrence rate of PTA following aspiration or incision for drainage and evaluated the risk factors for recurrence. METHODS: The medical records of 292 patients treated for PTA were reviewed. Recurrence of PTA and elective or quinsy tonsillectomy were the primary endpoints. A Cox proportional hazards regression model for PTA recurrence was constructed with sex, age, and PTA history as predictors. RESULTS: Young age was the only significant predictor of PTA recurrence. Patients aged 15 to 24 years had a 30-day recurrence rate of 15.5% and a total recurrence rate of 26.6%. The total recurrence rate among patients over 30 years of age was significantly less at 4.0% (Fisher's exact test, p < .05). CONCLUSION AND SIGNIFICANCE: Based on our results, tonsillectomy should be considered for PTA patients between 15 and 25 years of age and, to effectively avoid future recurrence of PTA, should be performed urgently.

Perceptions of life and experiences of health care support among individuals one year after head and neck cancer treatment - An interview study.

PURPOSE: To examine how individuals treated for head and neck cancer perceive life one year after the end of treatment and how they experience supportive efforts from health care. METHODS: A semi-structured interview study of 21 patients was performed one year after the end of treatment. The patients gave their views concerning physical, psychological, and return-to-work issues, and their experiences concerning rehabilitative efforts from health care and particularly the contact nurse were captured. A thematic analysis was conducted. RESULTS: One year after treatment the patients were still suffering from side effects and from fear of recurrence, but they strived to live as they did before the cancer diagnosis, such as having returned to work and resuming leisure activities. Moreover, the rehabilitative efforts from health care had ended. Having access to a contact nurse, also known as a clinical nurse specialist, was positive, however, the participants lacked regular long-term follow-ups with the contact nurse regarding rehabilitation needs. Improvement possibilities were seen in clarifying the role of the contact nurse and that the contact nurse should show engagement and make the initial contact with the patients. CONCLUSION: Despite the sequelae from treatment, the patients strived to live as before their diagnosis. By regular, engaged, and long-term follow-ups by the contact nurse, remaining needs may be uncovered, and appropriate individualized support and rehabilitation can be offered.

Carcinomas of the minor salivary glands of the oral cavity. A population-based study from the Swedish Head and Neck Cancer Register for 2008-2018.

BACKGROUND AND OBJECTIVES: Carcinomas of the minor salivary glands are rare with a heterogeneous pathology. This study explored the demographics, histology, treatment and survival in the Swedish population over 11 years. MATERIAL AND METHODS: Cases of salivary gland carcinomas in the oral cavity were extracted from the 'Swedish Head and Neck Cancer Register' (2008-2018). Statistical analyses with cross tabulation, age grouping, chi-square, the Kaplan-Meier method and log-rank tests were performed. RESULTS: Three hundred thirty cases were included (62% female; mean age 60 years; 83% were WHO Performance Status 0). The carcinomas were mostly stage I (57%), and the most common site was the palate with 165 tumours (50%). The most common histology was mucoepidermoid carcinoma (30%), followed by polymorphous low-grade adenocarcinoma (25%) and adenoid cystic carcinoma (24%). The distribution of histology differed between age groups. The five-year predicted overall survival rate was 83%. Most patients (89%) were treated with primary surgery. CONCLUSION AND SIGNIFICANCE: The demographics, histology, and survival of minor salivary gland carcinomas in the oral cavity in the Swedish population correspond well with previously published material. The demographics and histology differ from carcinomas of the major salivary glands in the same population.

Unique fiber phenotype composition and metabolic properties of the stapedius and tensor tympani muscles in the human middle ear.

The middle ear muscles have vital roles, yet their precise function in hearing and protection remains unclear. To better understand the function of these muscles in humans, the morphology, fiber composition, and metabolic properties of nine tensor tympani and eight stapedius muscles were analyzed with immunohistochemical, enzyme-histochemical, biochemical, and morphometric techniques. Human orofacial, jaw, extraocular, and limb muscles were used as references. The immunohistochemical analysis showed that the stapedius and tensor tympani muscles were markedly dominated by fibers expressing fast contracting myosin heavy chain MyHC-2A and MyHC-2X (79 ± 6% vs. 86 ± 9%, respectively, p = 0.04). In fact, the middle ear muscles had one of the highest proportions of MyHC-2 fibers ever reported for human muscles. Interestingly, the biochemical analysis revealed a MyHC isoform of unknown identity in both the stapedius and tensor tympani muscles. Muscle fibers containing two or more MyHC isoforms were relatively frequently observed in both muscles. A proportion of these hybrid fibers expressed a developmental MyHC isoform that is normally absent in adult human limb muscles. The middle ear muscles differed from orofacial, jaw, and limb muscles by having significantly smaller fibers (220 vs. 360 µm2 , respectively) and significantly higher variability in fiber size, capillarization per fiber area, mitochondrial oxidative activity, and density of nerve fascicles. Muscle spindles were observed in the tensor tympani muscle but not in the stapedius muscle. We conclude that the middle ear muscles have a highly specialized muscle morphology, fiber composition, and metabolic properties that generally showed more similarities to orofacial than jaw and limb muscles. Although the muscle fiber characteristics in the tensor tympani and stapedius muscles suggest a capacity for fast, fine-tuned, and sustainable contractions, their difference in proprioceptive control reflects different functions in hearing and protection of the inner ear.

High prevalence of pharyngeal bacterial pathogens among healthy adolescents and young adults.

The pharyngeal mucosa can be colonized with bacteria that have potential to cause pharyngotonsillitis. By the use of culturing techniques and PCR, we aimed to assess the prevalence of bacterial pharyngeal pathogens among healthy adolescents and young adults. We performed a cross-sectional study in a community-based cohort of 217 healthy individuals between 16 and 25 years of age. Samples were analyzed for Group A streptococci (GAS), Group C/G streptococci (SDSE), Fusobacterium necrophorum, and Arcanobacterium haemolyticum. Compared to culturing, the PCR method resulted in more frequent detection, albeit in most cases with low levels of DNA, of GAS (20/217 vs. 5/217; p < 0.01) and F. necrophorum (20/217 vs. 8/217; p < 0.01). Culturing and PCR yielded similar rates of SDSE detection (14/217 vs. 12/217; p = 0.73). Arcanobacterium haemolyticum was rarely detected (3/217), and only by PCR. Overall, in 25.3% (55/217) of these healthy adolescents and young adults at least one of these pathogens was detected, a rate that is higher than previously described. Further studies are needed before clinical adoption of PCR-based detection methods for pharyngeal bacterial pathogens, as our findings suggest a high incidence of asymptomatic carriage among adolescents and young adults without throat infections.

Forces Required for Isolated Malleus Shaft Fractures.

BACKGROUND AND HYPOTHESIS: Isolated malleus shaft fractures are rare cases. A commonly reported cause is a finger pulled out from a wet outer ear canal after a shower or bath. The objective was to investigate experimentally the mechanism and forces needed to establish an isolated malleus shaft fracture. METHODS: Ten fresh-frozen human temporal bones were adapted to allow visual inspection of the structures involved while negative pressure trauma was applied. Thirty malleus bones were broken and the required forces were measured. Measurements from 60 adult test subjects were used to create mathematical and physical models to calculate and measure the forces necessary for generating trauma. To calculate the maximum muscle force developed by the tensor tympani muscle, the muscle area and fiber type composition were determined. RESULTS: The temporal bone experiments showed that applied negative pressure in a wet ear canal could not fracture the malleus shaft with only passive counterforce from supporting structures, although the forces exceeded what was required for a malleus shaft fracture. When adding calculated counteracting forces from the tensor tympani muscles, which consisted of 87% type II fibers, we estimate that a sufficient force is generated to cause a malleus fracture. CONCLUSION: The combination of a negative pressure created by a finger pulling outward in a wet ear canal and a simultaneous counteracting reflexive force by the tensor tympani muscle were found to be sufficient to cause an isolated malleus fracture with an intact tympanic membrane.

A New, Promising Experimental Ossicular Prosthesis: A Human Temporal Bone Study With Laser Doppler Vibrometry.

OBJECTIVE: We compared the sound transmission using different types of total ossicular replacement prostheses (TORP); we then studied the performance of a new TORP that we designed inspired by the columella, the single ossicle found in birds. METHODS: Stapedial vibrations were measured on nine freshly frozen human temporal bones with laser Doppler vibrometry. We then compared the performances of eight common TORP positions or designs as well as the new silver prototype of bird-type prosthesis, designed also according to our digital holography patterns of the human tympanic membrane (TM). RESULTS: The TORPs placed in lateral contact with both the TM and the malleus handle outperformed, at most frequencies, those placed only in contact with the TM.The new bird-type prosthesis performed equally well or better than all other prostheses. CONCLUSION: If the malleus handle can be retained when placing a TORP, the best sound transmission can be achieved by placing the TORP in contact with both the distal part of the malleus handle and the TM. The good performance of our bird-type prosthesis suggests that there is still room for future improvement of prosthesis design to further optimize hearing outcomes after surgery.

Return to work after oropharyngeal cancer treatment-Highlighting a growing working-age population.

BACKGROUND: To describe the frequency of patients returning to work after treatment for oropharyngeal cancer and to identify predictors and physical barriers that might interfere with the return to work process. METHODS: Cross-sectional study including 295 patients. Data were collected regarding work/sick leave situation at 1 month before diagnosis and 15 months after diagnosis. The situation before diagnosis was retrospectively recalled by the patients. Two subscales and two single items from the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-H&N35 were used. Data were analyzed with multivariate logistic regression. RESULTS: Fifteen months after diagnosis, 212 patients (72%) were working. To be working 15 months after diagnosis was associated with working before diagnosis. Swallowing difficulties, problems talking on the telephone, and physical appearance were negatively associated with returning to work. CONCLUSIONS: The large number of individuals returning to work is encouraging for patients diagnosed with oropharyngeal cancer.

Patients' experiences of living with superior canal dehiscence syndrome.

OBJECTIVE: The study investigated how the symptoms of superior canal dehiscence syndrome (SCDS) affected patients in their daily life, and how patients coped with the disease. DESIGN: This was a qualitative study; semi-structured interviews were performed and analysed according to the systematic text condensation method. STUDY SAMPLE: Twelve of 13 identified patients with SCDS in the county of Norrbotten, Sweden, were included in the study. RESULTS: Five main categories were created based on the patients' experiences of living with SCDS: (1) Experiencing strange symptoms: One "new" symptom was identified - mental fatigue. (2) A restricted life socially, physically and at work: All patients experienced some extent of limitation in their daily life. (3) To accept and to protect oneself: All patients had developed strategies to protect their ears from noise. (4) Misunderstood in health care: The diagnosis was sometimes delayed several years due to lack of knowledge among healthcare workers. (5) Carefully considering treatment (surgery): Symptoms were weighed against the risk of side effects. CONCLUSIONS: SCDS was rendered an invisible disability. In the present study, we identified mental fatigue as a symptom not previously considered in the literature.

An Optimal Partial Ossicular Prosthesis Should Connect Both to the Tympanic Membrane and Malleus: A Temporal Bone Study Using Laser Doppler Vibrometry.

OBJECTIVE: To compare stapes vibrations in different partial ossicular replacement prosthesis (PORP) applications. METHODS: Stapedial vibrations were measured on fresh frozen human temporal bones with laser Doppler vibrometry. Eight different types of common ossiculoplasty methods were compared regarding recovery of stapes vibrations in relation with the normal ossicular chain. The PORPs were divided into three groups: 1) PORPs with the lateral contact only with the tympanic membrane, 2) PORPs with lateral contact only to the malleus handle, and 3) PORPs with lateral contact with both the malleus handle and the tympanic membrane. RESULTS: The PORPs with lateral contact only to the malleus handle performed better than the PORPs with lateral contact to the tympanic membrane only at 2 kHZ, but the best recovery was found in the group with contact both to the malleus handle and the tympanic membrane. CONCLUSION: The best sound transmission might be achieved by placing a PORP in contact with both the tympanic membrane and the handle of the malleus.

When Maxillary Sinusitis Does Not Heal: Findings on CBCT Scans of the Sinuses With a Particular Focus on the Occurrence of Odontogenic Causes of Maxillary Sinusitis.

Objectives: This study sought to investigate the proportion of patients with suspected sinusitis referred for radiological examination who have radiologically verified sinusitis of odontogenic origin and to describe this type of sinusitis. Study Design: This investigation is a retrospective study. Methods: A total of 303 sinus examinations involving cone beam computed tomography (CBCT) performed at Sunderby Hospital, Luleå, Sweden in 2012 were independently reviewed by two radiologists. The number of cases of maxillary sinusitis and the correlation between maxillary sinusitis and odontogenic infections were determined. Results: Overall, 24% of the verified cases of sinusitis were odontogenic. An odontogenic origin was identified in 40% of unilateral maxillary sinusitis cases but only 6% of bilateral maxillary sinusitis cases (p = 0.0015). Forty-nine out of 54 patients with periapical destruction had adjacent mucosal swelling in the maxillary sinus, but only 15 of these patients satisfied the criteria for sinusitis. Conclusion: The present study confirms the close relationship between odontogenic infections and unilateral maxillary sinusitis. Level of Evidence 4.

Prevalence of Fusobacterium necrophorum in tonsils from patients with chronic tonsillitis.

CONCLUSION: There was a high prevalence of Fusobacterium necrophorum (FN) in patients with chronic tonsillitis in the age group 15-23 years. This indicates that FN might play an important role in the pathogenesis of chronic tonsillitis in this age group, which is also the age group in which chronic or recurrent tonsillitis is most common. OBJECTIVES: The role of FN in patients with acute and chronic tonsillitis is unclear. Thus, this study investigated the occurrence of FN in tonsils of patients with chronic tonsillitis. The aim of the study was to determine the prevalence of FN in patients that underwent tonsillectomy due to chronic tonsillitis. This study also investigated if FN was found at different areas in the tonsils. METHOD: One hundred and twenty-six consecutive patients undergoing tonsillectomy due to chronic tonsillitis were included from the ENT clinics at Sunderby Hospital and Gällivare Hospital, Sweden. Both children and adults were included to encompass various age groups (age =2-57 years). Culture swabs were taken from three different levels of the tonsils - the surface, the crypts, and the inner core of the tonsils. Selective agar plates for detecting FN were used for culture. Culture was also made for detecting ß-hemolytic streptococci, Haemophilus influenzae, and Arcanobacterium. RESULTS: FN was the most common pathogen (19%). The highest prevalence of FN was found in the age group 15-23 years (in 34% of the patients). FN was detected both at the surface and in the core of the tonsils. Furthermore, in the few patients where FN was not detected in all three areas, FN was always detected at the tonsillar surface, in spite of being an anaerobic bacterium. Streptococci group G and C also occurred most frequently (30%) in the same age group as FN (15-23 years), whereas Streptococci group A was more evenly spread among the age groups.

Ossiculoplasty on Isolated Malleus Fractures: A Human Temporal Bone Study Using Laser Doppler Vibrometry.

HYPOTHESIS: In the literature several surgical methods have been reported that aim to improve hearing in patients with isolated malleus fractures; however, it is still not clear which method gives the best results. BACKGROUND: In this study, laser Doppler vibrometry (LDV) was used to compare the outcome of different surgical methods on malleus fractures in fresh frozen human temporal bones. METHODS: Fractured malleus shafts of defrosted human temporal bones were repaired with bone cement, with a malleus prosthesis from cortical bone, or with a partial ossicular replacement prosthesis (PORP) from cortical bone, and LDV measurements were obtained for analysis. RESULTS: The best result was achieved with the bone cement only, applied directly at the site of the fracture. The malleus prosthesis and the PORP gave similar results. CONCLUSION: All three surgical methods gave good results, but when the distal end of the fractured malleus can be attached close to the proximal end, the technique using only cement tends to be the best option. If the parts are too far apart, a malleus prosthesis or a PORP would be good options.

The Gelfoam® plug: an alternative treatment for small eardrum perforations.

AIM: To examine if a Gelfoam® plug in combination with surgical removal of the perforation edges could be an alternative to the widely accepted fat plug treatment for smaller ear drum perforations. MATERIALS AND METHODS: A prospective study of 17 consecutive patients with persistent small ear drum perforations considered for myringoplasty. The perforations were central perforations 2 to 4 mm in diameter. Patient ages ranged from 6 to 83 years, and the operation was performed under general anesthesia with mask ventilation in children and under topical local anesthesia in adults. A Gelfoam® plug was inserted into the perforation after surgical removal of the perforation edges. The follow-up time was more than 3 months. RESULTS: The closure rate of the ear drum was 83% (15/18). Pure tone average (PTA) was 19 dB preoperatively and 16 dB postoperatively. CONCLUSIONS: We show for the first time in humans that a Gelfoam® plug in combination with surgical removal of the perforation edges seems to result in about the same closure rate as the fat plug technique in persistent small ear drum perforations. Moreover, the method using Gelfoam® is simpler and faster than the fat plug technique. We suggest that randomized studies comparing the Gelfoam® plug technique with the fat plug technique should be performed.

Self-inflicted negative pressure of the external ear canal: a common cause of isolated malleus fractures.

We report the investigation of the cause of isolated malleus fractures based on four recent patients at our clinic and five patients reported to us by Swedish otosurgeons. In recent years we have treated four patients with isolated malleus fractures. Colleagues in the Swedish Society of Otosurgeons were encouraged to send us reports on patients with diagnosed isolated malleus fractures, resulting in five more cases. A literature review focusing on the cause and management of this injury was also conducted. Eight of nine patients in the Swedish material had the same history. The patients had inserted a finger into the external auditory canal (most often after a bath) and then pulled it out. Immediately afterwards they experienced a short pain and a hearing loss. An audiogram revealed a conductive hearing loss. After exploration of the middle ear, the most common operation performed was ossiculoplasty. In the present material the most common cause of isolated malleus fractures was a sudden negative pressure in the external auditory canal created by a quick outward movement of a finger in the external ear canal. Since this fracture appears to be infrequent, it can easily be missed at otomicroscopic examination. Tympanometry and pneumatic otomicroscopy are helpful diagnostic tools.

Alloiococcus otitidis--otitis media pathogen or normal bacterial flora?

During the last decade a new potential otitis media pathogen, Alloiococcus otitidis, has been studied. It is still not clear whether this bacterium really is a pathogen, although it has been found in a high percentage of middle ear effusions in children. The present study aimed to investigate the presence of A. otitidis in the nasopharynx and outer ear canals, and to develop a culture method that would make it possible to isolate A. otitidis from these locations. Nasopharyngeal samples (n = 129) from children below 6 years were investigated by conventional culture on blood agar plates with 6% saline and rabbit antisera against A. otitidis, and by a PCR method. In the same way, we investigated 10 samples from vestibulum nasi of healthy persons, 68 samples from outer ear canals of patients with acute or chronic ear problems, and 24 samples from outer ear canals of healthy persons. In a rat model of acute otitis media, we instilled living A. otitidis into rat middle ears through the tympanic bulla and evaluated the outcome clinically by otomicroscopy at days 3, 6 and 14. Of the 129 nasopharyngeal cultures, 9 were positive for A. otitidis by PCR, but none by the culture method. Of the 68 samples from patients with running ears, 4 were positive for A. otitidis by PCR, but none by the culture method. Of the 24 healthy ear canals, 7 were positive for A. otitidis by PCR and 3 of them also by the culture method. No A. otitidis could be found from the vestibulum nasi. The rat experiment showed that the reactions in the middle ears were mild; we could not provoke a purulent acute otitis media in any of the rats. There was a 7% prevalence of A. otitidis in children below 6 years. The highest prevalence (29%) was found in outer ear canals of healthy persons, which strongly suggests that A. otitidis is part of the normal bacterial flora of the outer ear canal. The doubtful pathogenicity is also confirmed by the fact that--in the rat model--A. otitidis elicited only a mild response in the middle ear. It was possible to isolate A. otitidis using a blood agar plate with 6% saline.

A daily nasal spray with saline prevents symptoms of rhinitis.

OBJECTIVE: To ascertain whether a daily nasal spray with physiological saline could prevent symptoms of common cold in a population of otherwise healthy adults. MATERIAL AND METHODS: This was study involving 10 weeks of daily use of a nasal saline spray and 10 weeks of only recording symptoms. Young adults eligible for military service at an army barrack in Boden, Sweden were invited to participate in the study and 108 healthy conscripts aged approximately 20 years agreed to do so. Data were recorded by the participants in a diary at home. In the diary the participants noted symptoms such as rhinitis, blocked nose, cough, fever and sore throat (pharyngeal pain). They also recorded inability to perform their duties due to the symptoms, and any medication or antibiotics necessitated by upper respiratory tract infection. RESULTS: A total of 69 subjects completed the 20-week diary period. For 60 of them, compliance during the spray period exceeded 60% and their data were used in the statistical calculations. During the spray period the number of days with nasal secretion and/or blocked nose (mean 6.4 days) was significantly (p=0.027) lower than that during the observation period (mean 11 days). Furthermore, the participants had a mean of 0.7 episodes of upper respiratory tract infection during the spray period, compared with 1.0 episodes during the observation period (p=0.05). CONCLUSION: A daily nasal spray with saline can prevent nasal symptoms of common cold in a population of otherwise healthy adults.

Is hydrogen peroxide responsible for the inhibitory activity of alpha-haemolytic streptococci sampled from the nasopharynx?

OBJECTIVE: The inhibitory effect of alpha-haemolytic Streptococci (AHS) in vitro on the three commonest otitis media pathogens, Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis, was previously investigated. The aim of this study was to determine the mechanism of this inhibitory activity. MATERIAL AND METHODS/RESULTS: When fractions of AHS filtrate were assayed to determine their inhibitory activity after size-exclusion chromatography, the inhibitory activity was found in the fractions with a low molecular weight. The inhibitory effect was completely reversed when catalase was added to the cell-free filtrate of AHS. A quantitative method also revealed high production (approximately 3 mmol/l) of hydrogen peroxide in the AHS filtrate with the best inhibitory activity. Electron microscopy of bacteria exposed to AHS filtrate with an inhibitory effect showed changes similar to bacteria exposed to hydrogen peroxide. CONCLUSIONS: We conclude that the inhibitory effect of AHS is most likely due to the production of hydrogen peroxide. The significance of hydrogen peroxide production of AHS is discussed in relation to the non-specific and specific mucosal defence systems.

Bacterial adherence to pharyngeal cells: in vitro studies with alpha-haemolytic streptococci and Haemophilus influenzae.

We examined the adherence to pharyngeal cells of alpha-haemolytic Streptococci (AHS) and Haemophilus influenzae, representing normal flora and otitis media (OM) pathogens, respectively. The bacteria were incubated with epithelial cells brushed from the tonsils, adenoid or tubal orifice of children and adults. Adherence varied among the clinical isolates of AHS and H. influenzae. AHS adhered better to epithelial cells from a child compared with those sampled from an adult. The bacteria adhered better to cells from the tubal orifice compared with those sampled from the adenoid. The selective attachment of AHS to certain cells but not to others could not be correlated to apoptotic/necrotic cells versus viable cells. Incubation of epithelial cells with an isolate of AHS with good inhibitory activity against OM pathogens showed almost no adherence of bacteria to the epithelial cells after 12 and 24 h of incubation. If, however, an isolate of AHS with weak inhibitory activity was incubated with the cells, the bacteria that were attached to the epithelial cells from the beginning showed overgrowth in the broth and increasing attachment to the cells after 12 and 24 h. Thus the inhibitory activity of AHS could also affect the adherence of potential pathogens to the mucosal surfaces. The adherence pattern may at least partially explain the difference in susceptibility to OM between children and adults.

Bacterial interference between pathogens in otitis media and alpha-haemolytic Streptococci analysed in an in vitro model.

Bacterial interference studied by means of agar methods has shown a decreased number of inhibitory alpha-haemolytic Streptococci among otitis-prone children. Additional information was gained regarding the interplay between alpha-haemolytic Streptococci (AHS) and otitis media (OM) pathogens by comparing the bacterial interference in broth with the interference activity studied using agar overlay methods. We found, that non-typeable Haemophilus influenzae (NTHI) and Moraxella catarrhalis are readily inhibited by AHS in broth. Streptococcus pneumoniae was more bacteriostatically inhibited. If two OM pathogens were inoculated simultaneously, an isolate of AHS with poor inhibitory activity was not able to inhibit the growth, in contrast to an isolate of AHS with good inhibitory activity. The initial amount of AHS inoculated with M. catarrhalis seemed to play a decisive role with respect to the inhibitory activity. M. catarrhalis developed reduced susceptibility against AHS both in vivo and in vitro. In vivo studies showed that children with secretory otitis media had fewer isolates of AHS in their nasopharynx with the ability to inhibit all the test pathogens than healthy children (p < 0.001). Although the factor(s) responsible for the inhibitory activity have thus far not been defined, we could exclude low pH and nutrition depletion as the inhibitory mechanism of AHS with good inhibitory activity.