Variations of aminoglycoside acetyltransferase (AAC) and aminoglycoside adenylyltransferase (AAD) also confer resistance: resistance in Pseudomonas aeruginosa is caused by AAC(6)-IV, which also confers resistance to kanamycin, gentamicin, and tobramycin, and resistance in Staphylococcus aureus and S. epidermidis is caused by AAD(4,4), which also confers resistance to kanamycin, tobramycin, and apramycin. Some strains of S. aureus can also inactivate amikacin by phosphorylating it. Pharmacokinetics
Amikacin is not absorbed orally and thus must be administered parenterally. It reaches peak serum concentrations in 0.5–2 hours when administered intramuscularly. Less than 11% of the amikacin actually binds to plasma proteins. It is distributed into the heart, gallbladder, lungs, and bones, as well as in bile, sputum, interstitial fluid, pleural fluid, and synovial fluids. It is usually found at low concentrations in the cerebrospinal fluid, except when administered intraventricularly. In infants, amikacin is normally found at 10–20% of plasma levels in the spinal fluid, but the amount reaches 50% in cases of meningitis. It does not easily cross the blood-brain barrier or enter ocular tissue.While the half-life of amikacin is normally two hours, it is 50 hours in those with end-stage renal disease.The vast majority (95%) of amikacin from an IM or IV dose is secreted unchanged via glomerular filtration and into the urine within 24 hours. Factors that cause amikacin to be excreted via urine include its relatively low molecular weight, high water solubility, and unmetabolized state.
Orchitis is inflammation of the testes. It can also involve swelling, pains and frequent infection, particularly of the epididymis, as in epididymitis. The term is from the Ancient Greek ὄρχις meaning "testicle"; same root as orchid. Signs and symptoms
Symptoms of orchitis are similar to those of testicular torsion. These can include:
hematospermia (blood in the semen)
hematuria (blood in the urine)
severe pain
visible swelling of a testicle or testicles and often the inguinal lymph nodes on the affected side. Causes
Orchitis can be related to epididymitis infection that has spread to the testicles (then called "epididymo-orchitis"), sometimes caused by the sexually transmitted diseases chlamydia and gonorrhea. It has also been reported in cases of males infected with brucellosis. Orchitis can also be seen during active mumps, particularly in adolescent boys.Ischemic orchitis may result from damage to the blood vessels of the spermatic cord during inguinal herniorrhaphy, and may in the worst event lead to testicular atrophy. Diagnosis
Blood – ESR high
Urine – Cultural & Sensitivity test
Ultrasound scanning

Treatment
In most cases where orchitis is caused by epididymitis, treatment is an oral antibiotic such as cefalexin or ciprofloxacin until infection clears up. In both causes non-steroidal anti-inflammatory drugs such as naproxen or ibuprofen are recommended to relieve pain. Sometimes stronger pain medications in the opiate category are called for and are frequently prescribed by experienced emergency department physicians. Other animals
Orchitis is not rare in bulls and rams. It has also been described in roosters. References
Further reading
Lefort C, Thoumas D, Badachi Y,  et al. (July 2001).