Differential testing
Audiometry
Fixation of the stapes within the oval window causes a conductive hearing loss. In pure-tone audiometry, this manifests as air-bone gaps on the audiogram (i.e. a difference of more than 10 dB between the air-conduction and bone-conduction thresholds at a given test frequency). However, medial fixation of the ossicular chain impairs both the inertial and osseotympanic modes of bone conduction, increasing the bone-conduction thresholds between 500 Hz and 4 kHz, and reducing the size of air-bone gaps. As 2 kHz is the resonant frequency of the ossicular chain, the largest increase in bone-conduction threshold (around 15 dB) occurs at this frequency – the resultant notch is called Carharts notch and is a useful clinical marker for medial ossicular-chain fixation.Tympanometry measures the peak pressure (TPP) and peak-compensated static admittance (Ytm) of the middle ear at the eardrum. As the stapes is ankylosed in otosclerosis, the lateral end of the ossicular chain may still be quite mobile. Therefore, otosclerosis may only slightly reduce the admittance, resulting in either a shallow tympanogram (type AS), or a normal tympanogram (type A). Otosclerosis increases the stiffness of the middle-ear system, raising its resonant frequency. This can be quantified using multi-frequency tympanometry. Thus, a high resonant-frequency pathology such as otosclerosis can be differentiated from low resonant-frequency pathologies such as ossicular discontinuity.In the absence of a pathology, a loud sound (generally greater than 70 dB above threshold) causes the stapedius muscle to contract, reducing the admittance of the middle ear and softening the perceived loudness of the sound.
Ceftazidime/avibactam, sold under the brand name Avycaz among others, is a fixed-dose combination medication composed of ceftazidime, a cephalosporin antibiotic, and avibactam, a β-lactamase inhibitor. It is used to treat complicated intra-abdominal infections, urinary tract infections, and pneumonia. It is only recommended when other options are not appropriate. It is given by injection into a vein.Common side effect include nausea, fever, liver problems, headache, trouble sleeping, and pain at the site of injection. Severe side effects may include anaphylaxis, seizures, and Clostridioides difficile-associated diarrhea. While use appears to be safe in pregnancy the medication has not been well studied in this group. Doses should be adjusted in those with kidney problems. Ceftazidime works by interfering with the building of the bacterial cell wall while avibactam works by preventing ceftazidimes breakdown.The combination was approved for medical use in the United States and the European Union in 2015. It is on the World Health Organizations List of Essential Medicines. Resistances are increasingly been reported with United States, Greece and Italy accounting for 80% of cases. Medical use
Ceftazidime/avibactam is used to treat certain multidrug-resistant gram-negative infections.Ceftazidime/avibactam is used for the treatment of:

complicated intra-abdominal infections. In these cases it is often used in combination with metronidazole, which provides coverage for anaerobic pathogens. complicated urinary tract infections, including acute pyelonephritis, in adults. hospital-acquired bacterial pneumonia and ventilator-associated bacterial pneumonia. Bacterial activity
For many bacterial infections, it offers little or no advantage over ceftazidime monotherapy, due to the widespread expression of resistance mechanisms other than β-lactamase production.