Indian Pediatrics 2000;37: 552-554
Septic Arthritis Due to Ureaplasma Urealyticum
Ureaplasma urealyticum is commonly found in the normal female genital tract(1) and has been implicated in chorioamnionitis(2), post partum infection(3), urethritis(4), infection stones(5) and respiratory infection especially in newborns(6). Septic arthritis due to U. urealyticum especially in hypogamma-globulinemic patients has been reported in literature(7-9) but none from our country. The current report describes a case of septic arthritis in which U. urealyticum was isolated from synovial fluid.
A 10-year-old girl presented to Orthopedics Department in March 1999 with one month history of pain and swelling of left knee joint. She had fever, weight loss, movement limitation, joint painful to palpation, pain on joint movement and had history of trauma to the left knee joint while playing. She was also having symptoms suggestive of urethritis for last three months and was taking antibiotics as prescribed by the private practitioner.
On examination, the knee was warm with erythema of the overlying skin and moderate effusion. Fine needle aspiration cytology (FNAC) of left knee showed straw colored fluid and the smears made from this fluid showed mild to moderate cellularity, composed of 18000 WBC/mm3 with 75% polymorpho-nuclear cells and few lymphocytes. No organism was seen on Gram stain or acid fast stains or on stains to detect fungi. The fluid was cultured on to blood agar, Mc-Conkey agar, Lowenstein Jensen media and Sabouraud’s dextrose agar for aerobic and anaerobic bacteria, mycobacteria and fungi, respectively. Cultures for mycoplasma were performed using pleuropneumonia like organisms (PPLO) broth and agar with urea and phenol red for U. urealyticum and arginine and phenol red for Mycoplasma hominis. All cultures were sterile except for PPLO broth with urea and phenol red which showed color change from yellow to pink. The broth was sub-cultured on to PPLO agar plates which grew small colonies (15-30 um) of U. urealyticum after two days. The organisms were further identified by standard methods(10): (a) growth in medium at pH-6; (b) hydrolysis of urea; (c) b-hemolysis; (d) hemadsorption; (e) inhibition of growth by thallium acetate (0.01 w/v) and erythromycin; and (f) growth inhibition and metabolic inhibition test. Radiograph of the left knee showed slight erosions and effusion. The blood chemistry and complete blood cell count were normal; the erythrocyte sedimentation rate was 45 mm/hour.
Initially, this patient was admitted to some private hospital and received therapy with ampicillin, ciproflox, and cephalexin which showed no improvement in her conditions. After isolation of U. urealyticum from synovial fluid, antibiotics were switched on to tetra-cycline and the patient reported improvement. The signs and symptoms subsided after 10 days of therapy.
We feel that on the basis of clinical and microbiological evidences presented above, Ureaplasma urealyticum was responsible for the septic arthritis that developed in this patient. To our knowledge, this is the first report of septic arthritis due to Ureaplasma urealyticum from our country. Vittecoq et al.(11) have isoalted Ureaplasma urelyticum from the joint in an immunocompetent individual with destructive polyarthritis initially suggestive of septic arthritis. However in literature, there has been now increasing evidence that U. urealyticum recovered from joints of hypogammaglobulinemic patients with septic arthritis are the cause of disease(7–9,12–15). In the current report, the patient was apparently healthy but the immune status was not evaluated formally. U. urealyticum is capable of producing pyogenic infection and it produces very mild inflammation. This organism is easily overlooked as it is not routinely sought and is only suspected if routine cultures are negative or the condition is unresponsive to broad spectrum antibiotics. A positive culture for mycoplasmas/ureaplasmas, especially from a normally sterile site and particularly in the absence of other micro-organisms, is sufficient justification for treatment of patients suffering from a condition known to be caused by or associated with ureaplasmas. This child had a rapid clinical response to tetracycline.
U. urealyticum is part of normal flora of female lower urogenital tract and thus mechanism of spread to the target joint may be hematogenous. Dissemination infection has been reported in otherswise healthy individuals. This patient was having persistent urethritis and U. urealyticum arthritis is known to be associated with the former condition. More studies are needed, especially in immuno-suppressed individuals to evaluate the association of mycoplasma/ureaplasma with septic arthritis since these organisms may represent a cause of opportunistic infection.