Hematoma infection with Mycoplasma hominis following transplant nephrectomy

Abstract

17May2000Immune dysfunction is a recognized feature of end-stagerenal disease and is increased with immunosuppressive drugsfollowing transplantation. Uncommon microorganismsusuallyof low virulence may become major pathogens in thisclinical setting.We report the successful treatment ofMyco-plasma hominis infection of a hematoma post-renal transplantnephrectomy, with cipro£oxacin monotherapy. Determina-tion of the minimum inhibitory concentration (MIC) ofcipro£oxacinbybreakpointtestingoftheisolateandmonitor-ing of antibiotic levels played an essential part in this patient’smanagement.An18-year-oldwomanreceivedacadavericrenal transplantforend-stagerenaldiseasesecondarytochronic glomerulone-phritis and accelerated hypertension. Flucloxacillin andaztreonam were administrated as perioperative prophylaxis.There was good initial graft function; however, acute graftrenal vein thrombosis occured, requiring graft nephrectomyon the third day following transplantation. Immunosuppres-sive therapy (azathioprine, cyclosporin and prednisolone) wasstopped and continuous ambulatory peritoneal dialysis(CAPD) was recommenced. On the ¢rst day post nephrect-omy she became pyrexial.The fever persisted despite empiri-cal treatment with vancomycin 1g twice a day andcipro£oxacin 400mg twice a day, intravenously, for a pre-sumed central venous line infection. All cultures at this timewere negative. On day 8, computed tomography (CT) of theabdomen showedanextensivemasssuggestiveofa hematomain the transplant bed. At exploratory laparotomy, the hema-tomawas evacuatedand specimensweresentfor bacteriologi-cal culture. These hematoma specimens and transplant bedswabswere cultured routinelyonblood and McConkey’s agaraerobically, and blood agar containing neomycin, anaerobi-cally. In view of this patient’s continuing pyrexia the platesunderwent prolonged incubation. After 4 days, transluscentpin-point colonies were noted on both aerobic and anaerobicblood agar, but no growth on McConkey’s agar.These colo-nies, which failed to stain by Gram’s method, were identi¢edas M. hominis. Antibiotic treatment was therefore changed to600mgclindamycin four times adayand 400mgintravenouscipro£oxacintwiceaday,onday12.Allsubsequentspecimensfrom this patient underwent prolonged culture for the isola-tion of M. hominis. Postoperative deep and super¢cial woundswabs,wound drain£uidandthetipofthedrain insertedintothe bed of the renal graft when the hematomawas evacuated,were all positive for M. hominis. Notably, blood cultures,endocervical and urethral swabs, midstream urine, peritonealdialysis £uid, throat and perineal swabs taken on day12 wereculture negative for M. hominis. Antibiotic susceptibility wasdetermined by breakpoint sensitivity testing.The hematomaisolatewas inoculated onblood agar plates containing1and 4mg/L ofcipro£oxacin and incubated anaerobically for5 days.M. hominis grew in the absence of cipro£oxacin, but wasinhibited by the presence of 1mg/L of cipro£oxacin. After 3days of antibiotic treatment the patient became apyrexial.Unfortunately, on day12 the patient developed diarrhoea duetoClostridiumdi⁄cile,con¢rmedbyatoxin-positivestool sam-ple. She improved clinically on cipro£oxacin monotherapyand onday14 her treatment was changed to oralcipro£oxacin500mg two times a day. After 48h of this oral dose, 2 h post-dose serum and peritoneal dialysate cipro£oxacin levels were1.7mg/Land2.2mg/L,respectively.Cipro£oxacinwas there-fore increased to 750mg twice a day. She remained apyrexialand was dischargedhome on day 25 to complete a total of 4weeks of cipro£oxacin. A random serum cipro£oxacin levelondischargewas3.4mg/Landallwoundswabswereculture-negativeforM.hominis.M.hominisisfrequentlyisolatedfromthelower genitourin-ary tract in healthyadults and is usuallyassociatedwith infec-tions of the upper genitourinary tract [1]. Increasingly, M.hominis is implicated in extragenital infection. Sites of infec-tion include blood, joints, central nervous system, lowerrespiratorytractand surgicalwoundinfections[2].Ofthe lat-ter category, sternotomy wound infections due to M. hominishave beenwell described [3], often associated with immuno-