A rapid simultaneous antigen detection of Haemophilus influenzae and Streptococcus pneumoniae for predicting the prognosis of acute otitis media.

BACKGROUND: Rapid identification of causative bacteria in treatment of acute otitis media (AOM) is of paramount importance for appropriate antibiotic use. MATERIALS AND METHODS: This prospective observational study was conducted in 15 hospitals and clinics in Japan between 2018 and 2020. A new rapid antigen test kit (AOS-116), which simultaneously detects antigens for Streptococcus pneumoniae (Sp) and Haemophilus influenzae (Hi), was applied for middle ear fluids (MEFs) and nasopharyngeal secretions (NPSs) in patients with moderate to severe AOM. We investigated relationship between the results of rapid test, severity at initial visit, and clinical course. RESULTS: Regarding performance accuracy based on culture results, AOS-116 showed 1) high (>80%) sensitivity, specificity, and negative predictive value (NPV) in MEFs for both antigens, 2) high sensitivity, specificity, and positive predictive value (PPV) in NPSs for Hi antigen, and 3) high specificity, and PPV in NPSs for Sp antigen. Regarding predictive value of nasopharyngeal culture and antigen detection for causative middle ear pathogens, similar results were observed between AOS-116 and culture, which was characterized with high sensitivity and NPV for both pathogens. MEFs/NPSs positive for Hi antigen were significantly associated with eardrum findings, and severity. MEFs/NPSs positive for pneumococcal antigen were significantly associated with severity of otalgia, fever, and otorrhea. Among patients with prior antimicrobial treatment, improvement tended to be slower in cases positive for Hi than in cases negative. CONCLUSION: The rapid antigen detection test is useful as a decision-making tool for prescribing antimicrobial agents and may play an important role in promoting appropriate antimicrobial use.

Effects of gentian violet on refractory discharging ears infected with methicillin-resistant Staphylococcus aureus.

OBJECTIVE: To test the efficacy of topical treatment with gentian violet on methicillin-resistant Staphylococcus aureus (MRSA). STUDY DESIGN: Retrospective study. SETTING: Territorial referral centre. PATIENTS: Patients with discharging ears infected with MRSA alone or MRSA and Pseudomonas aeruginosa (PA). INTERVENTION: One percent gentian violet was applied. MAIN OUTCOME: Remission of discharge. RESULTS: Remission was obtained in 44 of 46 ears infected with MRSA, whereas remission was obtained in only 3 of 6 ears infected with MRSA and PA. The minimum inhibitory concentrations (MICs) of gentian violet for MRSA strains sensitive to topical application of gentian violet and strains resistant to this treatment were 0.03 microg/mL and 0.5%, respectively. The MIC for PA resistant to topical gentian violet treatment was higher than 32 microg/mL. CONCLUSIONS: Topical application of gentian violet is a useful option for the treatment of refractory discharging ears infected with MRSA. However, great care must be taken if there is any chance of the gentian violet reaching the middle ear.

Impact of antibiotics on pathogens associated with otitis media with effusion.

OBJECTIVE: To further understand the roles of bacteria and antibiotics in the development of otitis media with effusion (OME). METHODS: Samples of middle-ear effusion (MEE) were collected during the placement of ventilation tubes to treat chronic OME. Children with acute otitis media within the past three months were excluded from this study. We used polymerase chain reaction (PCR) to detect pathogens and to test the susceptibility of Streptococcus pneumoniae to penicillin. RESULTS: Among MEE samples from 52 children, PCR detected bacterial DNA in 32 per cent (24/75) of them. S. pneumoniae was detected more frequently in middle ears that required ventilation tube insertion at least twice compared with those requiring ventilation tube insertion only once (5/15 versus 4/60; p = 0.013). Higher levels of S. pneumoniae were detected in MEE from children with, than without, a long history of antibiotic administration (7/10 versus 2/14; p = 0.0187). The pbp genes of all isolated S. pneumoniae contained mutations. CONCLUSIONS: Long exposure to antibiotics might significantly influence the bacterial genome in MEE.