Original Paper Accepted: January 28, 2002 Nephron 2002;92:297–303 Effective Antibiotic Treatment of Methicillin-Resistant Staphylococcus aureus-Associated Glomerulonephritis Yasushi Nagaba a Yoshiyuki Hiki b Togo Aoyama a Takashi Sano a Takatoshi Matsuo a Takeshi Shimizu a Sumio Tateno a Hisato Sakamoto a Kouju Kamata a Hidekazu Shigematsu c Masaaki Higashihara a Yutaka Kobayashi a a Department of Internal Medicine, Kitasato University School of Medicine, Sagamihara, Kanagawa, of Internal Medicine, Nagoya University Daiko Medical Center, Nagoya, and c Department of Pathology, Shinshu University School of Medicine, Matsumoto, Japan b Department Abstract Background: A new type of glomerulonephritis following a methicillin-resistant Staphylococcus aureus (MRSA) infection has been reported. The purpose of this study is to elucidate the clinicopathological features and the responsiveness to treatment of the disease. Methods: We studied the treatment of 8 patients with glomerulonephritis related to MRSA infection. We observed the eight cases and analyzed clinical features, laboratory findings and histopathological data. Results: On admission, all patients had no renal abnormalities. One to four months after suffering from MRSA infection, severe proteinuria and hematuria developed. Renal biopsy specimens revealed moderate to severe mesangial proliferative glomerulonephritis with various degrees of crescent formation. Immunofluorescence studies showed IgA and C3. Antibiotic therapy was performed in six cases, resulting ABC © 2002 S. Karger AG, Basel 0028–2766/02/0922–0297$18.50/0 Fax + 41 61 306 12 34 E-Mail firstname.lastname@example.org www.karger.com Accessible online at: www.karger.com/journals/nef in successfully reducing the proteinuria in parallel with the decreased activity of MRSA infection in five cases. The other 2 cases received corticosteroid treatment after complete cessation of MRSA infection, but they had a relapse of MRSA infection and later died from sepsis. Conclusions: These results suggested that MRSA-associated glomerulonephritis might respond to antibiotic treatment in most cases. This also indicated that special care must be taken in the application of steroid therapy for the glomerulonephritis with crescents, even though the MRSA infection has gone into an inactive state. Copyright © 2002 S. Karger AG, Basel Introduction Glomerulonephritis occurring in the course of staphylococcal infection has been reported frequently since the first paper in 1961 by Powell et al. . Bacterial endocarditis [2, 3] and infected ventriculo-jugular shunt [4, 5] had been two main causes of the disease. Recently, Koyama and coworkers [6–8] found a new type of glomerulone- Yasushi Nagaba, MD Department of Internal Medicine Kitasato University School of Medicine 1-15-1 Kitasato, Sagamihara City, Kanagawa 228-8555 (Japan) Tel. +81 42 778 9981, Fax +81 42 778 9980, E-Mail email@example.com Downloaded by: Vanderbilt University Library 184.108.40.206 - 10/26/2017 4:25:55 PM Key Words Methicillin-resistant Staphylococcus aureus W Glomerulonephritis W Antibiotics Table 1. Clinical features in 8 patients with glomerulonephritis related to MRSA infection Case No. Age Sex Underlying condition Focus of infection Onset after Purpura infection weeks 1 2 3 4 5 6 7 8 73 56 75 35 51 67 54 23 M M M F M M M M submaxillary cancer subarachnoid hemorrhage diffuse panbronchiolitis atopic dermatitis deep burn abdominal aortic aneurysm hepatocellular carcinoma psoriatic arthritis pneumonia pyelonephritis pneumonia skin abscess skin graft infection aortic graft infection abscess of abdominal cavity skin abscess 6 8 8 16 4 4 8 12 Patients and Methods Patients Eight patients (7 males, 1 female) aged 23–75 years were examined. All patients were admitted to Kitasato University Hospital for treatment of various diseases other than renal disease between November 1989 and October 2000. At the time of admission, they had no proteinuria and serum creatinine levels were within normal limits. They also had no history of renal disease. Glomerulonephritis developed after MRSA infection in all cases. 298 Nephron 2002;92:297–303 Laboratory Examination Laboratory data were obtained by standard methods during routine examinations at Kitasato University Hospital. Blood, sputum, urine and pus from various foci were cultured, and sensitivity to antibiotics was tested to identify MRSA. Histological Examination Renal biopsy was performed in all patients. For light-microscopic examination, renal biopsy specimens were fixed with 10% buffered formalin solution, dehydrated in alcohol, embedded in paraffin, and cut into sections. Sections were stained with hematoxylin and eosin (HE), periodic acid Schiff (PAS), periodic acid silver methenamine (PAM) and Masson-Trichrome. For immunofluorescence examination, specimens were embedded in OCT compound (Sakura Co., Tokyo) and immediately frozen in liquid nitrogen. Specimens were cut into sections and fixed with acetone. All sections were stained with fluorescein isothiocyanate (FITC)-conjugated sheep antihuman IgG, IgA, IgM, C1q, C3, C4 and fibrinogen (Cappel, Durham, N.C., USA). For electron microscopy, all specimens were fixed with glutaraldehyde and osmium tetroxide, ultrathin sections were stained with lead citrate and uranyl acetate, and they were examined with an electron microscope (Hitachi, Tokyo). Results Clinical Features and Laboratory Findings Clinical features of the 8 patients with MRSA-associated glomerulonephritis are listed in table 1. Clinical data of glomerulonephritis for each case on admission, at the onset and minimal level after treatment are shown in figure 1. Table 2 lists the immunological findings at the onset of glomerulonephritis. All patients had normal renal function and no urinary abnormalities on admission. Underlying conditions were skin diseases in three patients, cancer in two patients, and lung, cerebral disease and aortic aneurysm in one patient each. MRSA was detected in all patients. The foci of MRSA infection were visceral Nagaba et al. Downloaded by: Vanderbilt University Library 220.127.116.11 - 10/26/2017 4:25:55 PM phritis following methicillin-resistant Staphylococcus aureus (MRSA) infection. This type has a different character from the classical type of glomerulonephritis that follows staphylococcal infection, and a unique mechanism is thought to be involved in the process of acquiring this glomerulonephritis. The clinical feature of this glomerulonephritis is rapidly progressive glomerulonephritis (RPGN) with polyclonal Á-globulinemia (IgA and IgG), and proliferative glomerulonephritis with crescent lesions is often observed histopathologically. Immunofluorescence study reveals predominant mesangial IgA deposits as well as C3. These findings suggest that the enterotoxins of MRSA play a role as superantigens in the occurrence of this unique glomerulonephritis. We report here 8 patients with MRSA-associated glomerulonephritis. The patients showed similar clinical courses and histopathological findings. The glomerulonephritis in these patients was speculated to occur due to the same pathogenesis. The purpose of this study is to elucidate the clinicopathological features and the responsiveness to the treatment of this disease. + + – + + + + + Fig. 1. Proteinuria, urinary occult blood and level of serum creatinine on admission, at the onset of glomerulonephritis and minimum levels after treatment in antibiotics treatment patients and steroid treatment patients. UP = Urinary protein; UB = urinary occult blood; Cr = serum creatinine; MINO = minocycline; OFLX = ofloxacin; VCM = vancomycin. abscess in 5 patients and skin abscess in 3 patients. The period from MRSA infection to the onset of glomerulonephritis ranged from 4 to 16 weeks. While they were suffering from MRSA infection, severe proteinuria and hematuria developed in addition to a polyclonal increase in Áglobulins (IgG and IgA) in all patients. Rapid increase of serum creatinine levels was observed in 5 patients. Circu- lating immune complex (CIC) was detected in all patients, but the increases of the titers varied. Five patients had slight increases of antinuclear antibody (ANA) titer. In 7 patients, purpura was noticed at the same time as the onset of glomerulonephritis. Myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) was negative in 2 cases and not measured in 6 cases. Treatment of MRSA Glomerulonephritis Nephron 2002;92:297–303 Downloaded by: Vanderbilt University Library 18.104.22.168 - 10/26/2017 4:25:55 PM 299 Table 2. Hematological and immunological findings at onset Case No. WBC /mm3 Hb g/dl Plt !104 ANA ! IgG mg/dl 1 2 3 4 5 6 7 8 13.2 11.6 11.8 12.1 8.6 10.4 16.5 11.9 38 38 48 22 31 32 23 31 160 40 – 40 – 40 – 40 2,440 1,910 2,460 1,900 1,550 2,270 2,150 2,220 12.5– 17.0 15.0– 35.0 Normal range 11,100 10,200 5,500 5,300 12,100 10,000 10,200 8,700 4,000– 9,000 – 960– 1,960 IgA mg/dl 521 1,040 697 529 553 572 419 285 IgM mg/dl C3 mg/dl C4 mg/dl CH50 U/ml CIC Ìg/dl Á-gl % 78 372 154 169 95 72 288 184 64 49 79 84 56 69 53 49 27 43 39 41 42 36 32 24 33 ND 60 46 39 18 53 38 13.4 2.6 5.1 2.7 2.9 1.5 1.1 3.9 33.2 26.6 34.9 22.1 23.1 25.7 25.3 34.4 120–450 70–360 50–105 14–44 25–45 0–3.0 10.5– 19.9 WBC = White blood cells; Hb = hemoglobin; Plt = platelets; ANA = antinuclear antibodies; CIC = circulating immune complex; Á-gl = Á-globulin. 300 Nephron 2002;92:297–303 formed again; however, he died of sepsis. Bacterial endocarditis and subarachnoid hemorrhage with bacterial embolism were found at autopsy. Case 8, a 24-year-old man, was admitted to our hospital for management of psoriatic arthritis with skin infection. MRSA was cultured from skin abscess and blood. Minocycline was given intravenously, general condition was soon improved, but MRSA cultured from a skin lesion persisted. Three months after MRSA infection was detected, proteinuria and hematuria were first pointed out and proteinuria gradually increased to the nephrotic range. Five months after MRSA infection, percutaneous renal biopsy was performed. Light-microscopic examination revealed mesangial proliferative glomerulonephritis with cellular crescents. Prednisolone was started for persistent massive proteinuria and impairment of renal function after C-reactive protein (CRP) was negative. The dose was 500 mg intravenously for the first 3 days and 50 mg orally for a month, with gradual tapering. The level of serum creatinine and proteinuria did not improve. Three months after steroid treatment was started, sudden consciousness disturbance developed. Computed tomography showed massive subcortical hemorrhage, and, finally, he died. Cerebral bacterial embolism was found at autopsy. Histopathological Examination Light-microscopic findings revealed necrotizing crescentic glomerulonephritis (fig. 2A) in 4 patients and mildto-moderate mesangial proliferative glomerulonephritis in 4 patients. Crescent formation of various degrees was Nagaba et al. Downloaded by: Vanderbilt University Library 22.214.171.124 - 10/26/2017 4:25:55 PM Treatment with antibiotics alone was performed in 6 patients. Four patients were treated with vancomycin alone, case 3 with minocycline and ofloxacin, case 4 with minocycline alone. All antibiotics were administered initially intravenously. Together with improvement of the MRSA infection by antibiotic therapy, proteinuria decreased and serum creatinine levels normalized within several weeks in 5 patients. Hemodialysis therapy was required in 1 patient (case 5) with severe glomerular and tubular damage. Recovery of renal function was not achieved (fig. 1). Another 2 patients (cases 7 and 8) received corticosteroid treatment. Case 7, a 55-year-old man, underwent a partial resection of the liver for hepatocellular carcinoma. He developed a liver abscess, treated initially by vancomycin, and subsequently by percutaneous drainage. MRSA was detected in the culture of abscess material and blood. A small cavity in the liver could be detected by abdominal ultrasonography, after CRP and the culture of the material from drain were negative. Four weeks after onset of MRSA infection, proteinuria and hematuria were detected for the first time. Five months after MRSA infection, renal biopsy was performed, and mesangial proliferative glomerulonephritis with cellular crescents was seen on light-microscopic examination. Prednisolone was started orally at a daily initial dose of 40 mg. Serum creatinine and proteinuria were improved by the treatment, but relapse of MRSA infection occurred 4 months after starting corticosteroid treatment. Recurrence of liver abscess was established by ultrasonography, and then vancomycin therapy and percutaneous drainage were per- Fig. 2. A Light micrograph of a glomerulus showing tuft necrosis and cellular crescents. !270, PAM. B Immunofluorescence micrograph of a glomerulus showing mesangial IgA deposits. !270. C Electron micrograph of a part of a glomerulus exhibiting paramesangial dense deposits and infiltration of monocytes in the capillary lumen and mesangium. Mesangial cell proliferation and endothelial swelling are prominent. !3,500. Mc = Mesangial cell; En = endothelial cell; Mo = monocyte; Dp = deposit. Treatment of MRSA Glomerulonephritis Discussion In 1995, Koyama’s group [6–8] reported a new type of glomerulonephritis occurring during the course of MRSA infection. They proposed that this new type be called superantigen-related glomerulonephritis (SARN), because the enterotoxin of MRSA was identified to act as a superantigen in the pathogenesis of glomerulonephritis following MRSA infection. Superantigens are potent immunostimulatory proteins of bacterial or viral origin that activate a large population of T cells by binding to the V beta domain of the T cell antigen receptor (TCR) at nanomolar concentrations when bound to major histocompati- Nephron 2002;92:297–303 301 Downloaded by: Vanderbilt University Library 126.96.36.199 - 10/26/2017 4:25:55 PM detected in 7 patients. Tubulointerstitial nephritis was observed in 6 patients (table 3). Immunofluorescence examination revealed IgA (fig. 2B) and C3 deposits in all the patients with a mesangial pattern (table 4). On the other hand, IgG deposits were found in only 1 patient. Electronmicroscopic findings revealed electron-dense deposits (fig. 2C) in mesangial areas in all patients (table 4). Table 3. Histological and immunofluorescence findings IF Case No. LM glomerular lesions crescents/ TIN glomeruli IgG IgA IgM C3 C4 C1q fib 1 2 3 4 5 6 7 8 necrotizing crescent GN mesangial proliferative GN mesangial proliferative GN mesangial proliferative GN necrotizing crescent GN mecrotizing crescent GN mesangial proliferative GN necrotizing crescent GN 17/33 0/3 2/32 2/20 22/23 12/35 2/20 9/22 – – – ++ – – – – ++ + ++ ++ + + ++ +++ ++ – + + ++ – – – + + ++ + +++ + ++ ++ – – – – + – – – – – – – + – – – + + – ++ ++ + – – + ++ – +/– ++ ++ – +/– LM = Light microscopic; IF = immunofluoresce; TIN = tubulointestinal nephritis; fib = fibrinogen; M = mesangial pattern; P = peripheral pattern. Case No. Deposits Mes End Epi 1 2 3 4 5 6 7 8 + + + + + + + + – – – – – – – + – – – – – – – + CMI Mesan- Glomeruli giolysis monocytes PMN – – + + + + – + + – – – + – + + + – + + + + – + + – – + + + – + Mes = Mesangial; End = endothelial; Epi = epithelial; CMI = circumferential mesangial interposition; PMN = polymorphonuclear leukocyte. bility complex (MHC) class II molecules, but they do not require processing. Superantigens have been implicated as a causative factor in a number of human diseases. A typical example is toxic shock syndrome where enterotoxin as a superantigen releases massive cytokines, mainly tumor necrosis factor-ß, interferon-Á, interleukin 1 and interleukin 6. The clinical effects of superantigens can be not only acute but also chronic. Recent evidence suggests that superantigens may play a central role in the pathogenesis of several autoimmune disorders such as rheumatoid arthritis, Kawasaki disease  and multiple sclerosis . 302 Nephron 2002;92:297–303 MRSA was first identified in the United Kingdom in 1961. The prevalence of MRSA infection has been reported by several dozen facilities worldwide. About 60% of S. aureus isolates obtained from patients in Japan during 1992 and 1993 were MRSA . Infection with MRSA is a significant problem for hospitalized patients in Japan. MRSA infection may occur in the compromised host such as elderly patients, especially patients with chronic disease or after surgery. Another important clinical feature is that MRSA infection often persists for longer periods, since most antibiotics are ineffective. Prolonged septicemia is an important precondition for the development of glomerulonephritis [6–8]. With increasing numbers of MRSA infection, MRSA-associated glomerulonephritis has been found in our hospital. The 8 patients in this study were thought to be compatible with the type of glomerulonephritis reported by Koyama’s group based on similarities of their clinical features and pathology. First, MRSA-associated glomerulonephritis was observed to follow a clinical course of rapidly progressive glomerulonephritis with nephrotic syndrome in most of the cases. This clinical feature may reflect the fact that superantigens could activate a large number of T cells in a short time. Second, laboratory findings showed a polyclonal increase of serum IgG and IgA, together with an increase of immune complexes. Third, histological findings revealed mesangial proliferative glomerulonephritis with crescent formation and the deposition of IgA and C3 in a mesangial pattern in glomeruli. One of the marked characteristics in this type of glomerulonephritis is the predominant mesangial deposition of Nagaba et al. Downloaded by: Vanderbilt University Library 188.8.131.52 - 10/26/2017 4:25:55 PM Table 4. Electron-microscopic findings IgA. This is the apparent point of digression from the classical type of glomerulonephritis induced by ventriculojugular shunt and bacterial endocarditis, which generally presents a predominant deposition of IgG [2–5]. Yoh et al.  suggested that IgA was a key factor in the development of MRSA-associated glomerulonephritis. The levels of serum creatinine and proteinuria changed in parallel with the activity of MRSA infection. The glomerulonephritis associated with MRSA infection was very responsive to antibiotics in most cases. Yoh et al. , in their case report, also reported that the levels of serum creatinine and proteinuria paralleled the course of the MRSA infection. Thus, this type of glomerulonephritis could be expected to improve if the MRSA infection improves. In reality, however, the problem remains that it is sometimes difficult to clinically confirm the complete clearance of the MRSA infection. CRP level and white blood cell count are useful markers of MRSA infection. But they do not always accurately reflect the activity of MRSA infection such as the presence of capsulated abscess. In this study, steroid therapy was performed in 2 patients after CRP and white blood cell count had decreased to normal range, because renal biopsies revealed mesangial proliferative glomerulonephritis with crescent formation and clinical feature was RPGN syndrome. Both cases eventually died of sepsis due to the adverse effects of corticosteroid. Considering these results, the first choice of treatment of MRSA-associated glomerulonephritis should be antibiotic therapy. In conclusion, MRSA-associated glomerulonephritis may show favorable responsiveness to antibiotic treatment in the majority of cases. This also indicated that special care must be taken in the application of steroid therapy for glomerulonephritis with crescents, even though the MRSA infection has gone into an inactive state. References Treatment of MRSA Glomerulonephritis 6 Koyama A, Kobayashi M, Yamaguchi N, Yamagata K, Takano K, Nakajima M, Irie F, Goto M, Igarashi M, Iitsuka T, Aoki Y, Sakurai H, Sakurayama N, Fukao K: Glomerulonephritis associated with MRSA infection: A possible role of bacterial superantigen. Kidney Int 1995; 47:207–216. 7 Kobayashi M, Koyama A: Methicillin-resistant Staphylococcus aureus (MRSA) infection in glomerulonephritis – a novel hazard emerging on the horizon. 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