PMC3892063_01
Clinical course of the patient. Abbreviations: CLDM, clindamycin; CPFX, ciprofloxacin; DIV, drip infusion; LZD, linezolide; MEPM, meropenem; MRSA, methicillin-resistant Staphylococcus aureus; MZN, metronidazole; TEIC, teicoplanin; VCM, vancomycin.
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F1
However, acute watery diarrhea amounting to 4 L/day (determined by inserting a rectal tube) together with pyrexia (38 C) was evident on day 19 (Figure  1). Although stool specimens were negative for Clostridium difficile toxins A and B, pseudomembranous colitis was considered and metronidazole (1 g/day) was started via a nasogastric tube (Figure  1). Intermittent pain in the right hip joint started on day 71 after he started rehabilitation for walking (Figure  1).
Gram staining findings of stool cultures. Fecal leukocytes are abundant.
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F2
However, the watery diarrhea was refractory to metronidazole, and Gram staining stool samples revealed abundant fecal leukocytes (Figure  2), suggesting colonic membranous damage.
Magnetic resonance imaging of right hip joint. T2-weighted image (T2WI) of hip joint shows high-intensity area surrounding head of right femur, indicating fluid collection (A). Fat saturated T2WI shows high-intensity area on right obturator externus or adducent muscles (B) that appears as a hotspot on gallium scintigram (C). Synovial fluid contains abundant leukocytes that are phagocytically engulfed by gram-positive cocci (D).
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F3
We explored the source of the fever and right hip joint pain using magnetic resonance imaging (MRI) (Figure  3A and B) and 67gallium scintigraphy of the hip joint. T2-weighted MRI (T2WI) revealed an area of high intensity around the head of the right femur indicating fluid collection (Figure  3A). Fat-saturated T2-weighted images (T2WI) revealed another area of high intensity on the right obturator externus or adducent muscles (Figure  3B), suggesting right hip arthritis that 67gallium scintigraphy confirmed as a hotspot (Figure  3C). Joint drainage fluid collected on day 100 showed abundant leukocytes enclosed by phagocytic gram-positive cocci (Figure  3D) that were later identified as MRSA.
Analysis of identified methicillin-resistant Staphylococcus aureus strains on pulsed-field gel electrophoresis. M, marker; 1, sputum (day 10); 2, stool (day 19); 3, intravenous hyperalimentation catheter (day 20); 4, blood (day 30); 5, sputum (day 44); 6, hip joint synovial fluid (day 100); C, control (Staphylococcus aureus, strain NCTC 8325).
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F4
Pulsed-field gel electrophoresis (PFGE) showed that the MRSA strains in the samples isolated from stool (day 19), blood (day 30) and synovial fluid (day 100) were identical (Figure  4), suggesting a hematological spread of MRSA originating from the colonic membrane damaged by MRSA enterocolitis.