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Unusual case of postoperative infection caused by Morganella morganii
CASE REPORTS
Unusual Case of Postoperative Infection Caused by Morganella morgan;; Ellen Yvonne
Gebhart-Mu~lIer,
DPM, Phuong Mueller, DPM, and Brent Nixon, DPM
Morganella morganii is a facultative Gram-negative anaerobe present in the human gastrointestinal system as normal flora. Clinically, the organism is important when it manifests as an opportunistic pathogenic infection elsewhere in the body. This paper reviews an unusual case in which M. morganii is the pathogen responsible for a devastating postoperative infection in a diabetic patient. Currently, there are no known reported cases in the literature of M. morganii as an etiologic pathogen for a postoperative foot infection. Prompt diagnosis and treatment of this organism is imperative to reduce the patient's overall morbidity and mortality. (The Journal of Foot & Ankle Surgery 37(2):145-147, 1998) Key words: foot, Gram-negative infection, postoperative infection, Morganella morganii
Historically, Gram-positive bacteria have been implicated as the most common infecting agent (1-3). Parental prophylactic antibiotics, such as cefazolin, are utilized in targeting these organisms, especially Staphylococcus aureus. Prophylactic antibiotics are now a routine part of the most clean orthopedic procedures. Many studies have shown a reduced infection rate with their use (4-8). Although Gram-positive organisms are the likely culprits in postoperative infection, Gram-negative bacteria should be suspected as well, especially after prophylactic antibiotics have been administered for S. aureus. Enteric bacteria such as Morganella morganii can cause devastating infection. Immunocompromised patients are especially at risk. The authors report such a case and present a discussion of microbiology and treatment of the infecting organism. Microbiology
M. morganii is a member of the Enterobacteriaceae family and is classified in the tribe Proteeae. It is a small, motile, non-spore-forming and noncapsulated, Address correspondence to: Ellen Y. Gebhart-Mueller, DPM, HarBer Medical Plaza, 307-C S. Thompson St., Springdale, AR 72764. Received for publication May 1997; accepted in revised form for publication August 1997. The Journal of Foot & Ankle Surgery 1067-2516/98/3702-0145$4.00/0 Copyright © 1998 by the American College of Foot and Ankle Surgeons
gram-negative bacilli. It is a facultative anaerobe found in normal gastrointestinal tract, soil, and sewage. It has also been implicated in nosocomial infections (9). On Gram stain it appears the same as other Enterobacteriaceae and must be distinguished by biochemical reactions (10). It is indole positive, urease positive, h2s production negative, and ornithine decarboxylase positive; acid from mannitol, maltose, and xylose are all negative. M. morganii is readily cultivatable on ordinary media such as blood agar and eosin methylene blue agar, which inhibits Grampositive bacteria. It also grows on selective media such as MacConkey's agar (10). It is distinguished from the closely related Proteus species when grown on media because of its lack of demonstrating the swarming phenomenon (10). Formerly, it was known as Proteus morganii until it was recognized as having a greater DNA content of guanine and cytosine than other members of the Proteeae (11). Case Presentation
A 57-year-old, insulin-dependent, diabetic male presented with a chief complaint of pain at the plantar exostosis of his medial cuneiform bone of the left foot. He had a history of pain for several years. The patient had a Charcot foot deformity with a history of chronic foot ulcers and callouses. He had a chronic ulcer over the left first metatarsal cuneiform joint that had recently VOLUME 37, NUMBER 2, MARCH/APRIL 1998
145
healed to a Wagner grade 0 lesion. Prior conservative treatment, such as frequent visits for debridement, custommolded shoes, and soft inserts, had provided temporary relief. With the ulcer now healed, the patient requested surgical intervention to remove the plantar prominence in an attempt to avoid future ulceration. An exostectomy with arthrodesis of the first metatarsal cuneiform joint was scheduled. Clinical examination revealed a well-developed white male with a Wagner grade 0 lesion approximately 1.5 cm diameter over the left first metatarsal cuneiform joint. There was no erythema, on drainage, and only minimal edema without tenderness over the left first metatarsal cuneiform joint. A palpable exostosis on the plantar aspect of the medial cuneiform was evident. The vascular status was intact with normal finding. The neurological exam was abnormal. There was no lymphadenopathy present. Radiographs of the left foot revealed a prominent exostosis on the medial cuneiform with large osteophytes projecting from the talonavicular and navicular-cuboidal joints with degenerative changes and marked pes planus consistent with Charcot foot. The patient was taken to the operating room 4 days later. Preoperative laboratory results were within normal limits. He was given 1 g of cefazolin for prophylaxis prior to surgery. The surgery was performed under local anesthesia with monitored anesthesia care. The left foot was prepped and draped in the usual sterile fashion. A lazy-S incision was then made from proximal to distal across the medial arch and dorsal to the previous ulcerative lesion. The incision was carried deeper with care to expose adequately the first metatarsal-cuneiform joint. The exostosis was then removed. The articular cartilage was removed and two 4.5-mm cannulated screws were placed for fixation. The wound was flushed and closed in the usual manner. A bulky dressing was applied and followed by a posterior splint. There were no breaks in sterile technique throughout the procedure. The patient had been admitted to the hospital after the procedure and complained of nausea, vomiting, abdominal pain, diarrhea, and fever within the first 24 hours. The wound was inspected and there were no signs of infection. He received the usual battery of tests, such as complete blood cell count, urinalysis, blood cultures, and chest radiography. He also received treatment for nausea, vomiting, fluid loss, pain, and diabetes management. The sutures were removed to allow drainage and to obtain a wound specimen. As time progressed to the 3 postoperative day, the classic signs of infection appeared at the surgical site. Blood and wound cultures revealed M. morganii. The urinalysis was positive for bacteria and white blood cells. It is interesting that preoperative urinalysis did not show an increase in white blood cells. Empirically, the patient had been placed on gentamicin 146
THE JOURNAL OF FOOT & ANKLE SURGERY
for Gram-negative coverage since he had Gram-positive coverage prophylactically. Postoperatively, he received cephalexin, 250 mg p.o.q.i.d. Therapeutically, cefoteton was added to gentamicin. The organism was susceptible to both antibiotics. The
FIGURE 1
Infected surgical site several days after surgery.
FIGURE 2 Sequella of unhealed surgical site after infection by Morganella morganii.
patient was transferred to the medicine service on the day of admission to investigate his abdominal pain. The patient still received care from the podiatry staff. In addition to antibiotic therapy, aggressive wound care was begun. Daily irrigation and debridement with dressing changes were provided. The wound was necrotic at the anterior aspect of the tibialis anterior tendon and tracted next to the screw fixation. The screw fixation was then removed (Fig. 1). Radiographs were then taken and were negative for osteonecrosis. One-year follow-up revealed that the wound had not healed completely (Fig. 2). Discussion
M. morganii is an enteric, non-spore-forming, Gramnegative bacillus. It is a well-known part of normal flora. The organism is the etiologic agent for a variety of infections. Infections secondary to M. morganii reported in the literature include those of the urinary tract, soft tissue, and abdomen (9). It has also manifested as septic arthritis (12) and is proven to be a nosocomial pathogen (9). This case illustrates the need for prompt identification of pathogens in order to provide immediate treatment to avoid the devastating sequella associated with postoperative infections. These measures include appropriate laboratory tests such as complete blood cell count with differential and urinalysis. The surgical wound must be inspected for the first signs of infection. This may include releasing sutures as in our case. Results from the Gram stain as well as clinical suspicion, such as appearance of the tissue and previous use of antibiotics, will determine empiric therapy. Approximately 48 hours later, culture and susceptibility results will return and provide further guidance. Local wound care, such as daily debridement and copious irrigation, are as important as antibiotics. The concept is to clean the wound well daily so the antibiotics can penetrate the viable tissue and be more effective by having fewer organisms to combat. Timing of the dressing changes will be dependent on the amount of drainage. Packing the wound with sterile antimicrobial packing material is useful in absorbing drainage in large, deep wounds. Infection secondary to M. morganii is well treated by the appropriate antibiotic once it has been identified. It is susceptible to a number of drugs. These include second- and third-generation cephalosporins, antipseudomonal penicillin, fluoroquinolones, trimethoprimlsulfamethoxazole, and some aminoglycosides such as gentamicin and amikacin. It is also susceptible to imipenem and aztreonam. As mentioned above, susceptibility results will provide guidance in choosing an antibiotic as resistance becomes an increasing concern.
Susceptibility varies from region to region in treating bacterial infections. Summary
Infection of any type creates a serious situation which can be very debilitating to the patient if not managed properly. The patient in our case appeared to be free of infection prior to surgery. Symptoms were nearly immediate after surgery. Immunocompromised patients, such as those with diabetes mellitus, may be unable to mount a response. It is speculated by the authors that the patient had the M. morganii infection prior to the surgery and the stress of the surgical procedure proliferated the infectious process. The patient was given prompt infection management with immediate antibiotic coverage, yet there was much necrosis throughout the wound. The patient continues to have a nonhealed wound. References 1. Tachdilian, M. 0., Compere, E. L. Postoperative wound infections in orthopaedic surgery. Evaluation of prophylactic antibiotics. J. Int. cen. Surg. 28:979, 1957. 2. Williams, D. N. Antibiotic prophylaxis in bone and joint surgery. In Orthopaedic Infections - Diagnosis and Treatment, pp. 60- 74, edited by R. B. Gustillo, W.B. Saunders, Philadelphia, 1989. 3. Cruse, P. J. E. Wound infections - epidemiology and clinical characteristic. In Surgical Infectious Disease, 2nd ed., pp. 319-329 Appleton Lange, Norwalk, CT, 1988. 4. Burke, J. P. The effective period of preventive antibiotic action in experimental incisions and dermal lesions. Surgery 50: 161, 1961. 5. Fogelberg, E. V., Zitzman, E. K., Stinchfield, F. E. Prophylactic penicillin in orthopaedic surgery. J. Bone Joint Surg. 52-A:95, 1970. 6. Bowers, H. W., Wilson, F. c., Green, W. B. Antibiotic prophylaxis in experimental bone infection. J. Bone Joint Surg. 55-A:125l, 1973. 7. Boyd, R. J., Burke, J. P., Colton, T. A double-blind clinical trail of prophylactic antibiotics in hip fractures. J. Bone Joint Surg. 55A:125l, 1973. 8. Classen, D. C., Evans, R. S., Pestotnik, S. L., Hom, S. D., Menlove, R. L., Burke, J. P. The timing of prophylactic administration of antibiotics and the risk of surgical wound infection. N. Engl. 1. Med. 326:281, 1992. 9. Mulligan, M. E. In vitro activity of cefixime and six other agents against nosocomial pathogens of the Enterobacteriaceae family. Infection Control 8(6): 241, 1987. 10. Freeman, B. A. The enteric bacilli: Klebsiella, Enterobacter, Serratia, Proteus, Providentia, and Morganella, ch.20. In The Burrow Textbook of Microbiology, 22nd ed., p.483, W. B. Saunders, Philadelphia, 1985. 11. Silverblatt, F. J., Weinstein, R. Enterobacteriaceae, edited by Principles and Practice of Infectious Disease, pp. 1226-1236, G.L. Mandell, R.G. Douglas, Jr., and Bennett, 1. E., John Wiley, New York, 1985. 12. Schonwetter, R. S., Orson, F. M. Chronic Morganella morganii arthritis in an elderly patient. J. Clin. Microbiol. 26:7, 1988.
VOLUME 37, NUMBER 2, MARCH/APRIL 1998
147
Unusual Case of Postoperative Infection Caused by Morganella morgan;; Ellen Yvonne
Gebhart-Mu~lIer,
DPM, Phuong Mueller, DPM, and Brent Nixon, DPM
Morganella morganii is a facultative Gram-negative anaerobe present in the human gastrointestinal system as normal flora. Clinically, the organism is important when it manifests as an opportunistic pathogenic infection elsewhere in the body. This paper reviews an unusual case in which M. morganii is the pathogen responsible for a devastating postoperative infection in a diabetic patient. Currently, there are no known reported cases in the literature of M. morganii as an etiologic pathogen for a postoperative foot infection. Prompt diagnosis and treatment of this organism is imperative to reduce the patient's overall morbidity and mortality. (The Journal of Foot & Ankle Surgery 37(2):145-147, 1998) Key words: foot, Gram-negative infection, postoperative infection, Morganella morganii
Historically, Gram-positive bacteria have been implicated as the most common infecting agent (1-3). Parental prophylactic antibiotics, such as cefazolin, are utilized in targeting these organisms, especially Staphylococcus aureus. Prophylactic antibiotics are now a routine part of the most clean orthopedic procedures. Many studies have shown a reduced infection rate with their use (4-8). Although Gram-positive organisms are the likely culprits in postoperative infection, Gram-negative bacteria should be suspected as well, especially after prophylactic antibiotics have been administered for S. aureus. Enteric bacteria such as Morganella morganii can cause devastating infection. Immunocompromised patients are especially at risk. The authors report such a case and present a discussion of microbiology and treatment of the infecting organism. Microbiology
M. morganii is a member of the Enterobacteriaceae family and is classified in the tribe Proteeae. It is a small, motile, non-spore-forming and noncapsulated, Address correspondence to: Ellen Y. Gebhart-Mueller, DPM, HarBer Medical Plaza, 307-C S. Thompson St., Springdale, AR 72764. Received for publication May 1997; accepted in revised form for publication August 1997. The Journal of Foot & Ankle Surgery 1067-2516/98/3702-0145$4.00/0 Copyright © 1998 by the American College of Foot and Ankle Surgeons
gram-negative bacilli. It is a facultative anaerobe found in normal gastrointestinal tract, soil, and sewage. It has also been implicated in nosocomial infections (9). On Gram stain it appears the same as other Enterobacteriaceae and must be distinguished by biochemical reactions (10). It is indole positive, urease positive, h2s production negative, and ornithine decarboxylase positive; acid from mannitol, maltose, and xylose are all negative. M. morganii is readily cultivatable on ordinary media such as blood agar and eosin methylene blue agar, which inhibits Grampositive bacteria. It also grows on selective media such as MacConkey's agar (10). It is distinguished from the closely related Proteus species when grown on media because of its lack of demonstrating the swarming phenomenon (10). Formerly, it was known as Proteus morganii until it was recognized as having a greater DNA content of guanine and cytosine than other members of the Proteeae (11). Case Presentation
A 57-year-old, insulin-dependent, diabetic male presented with a chief complaint of pain at the plantar exostosis of his medial cuneiform bone of the left foot. He had a history of pain for several years. The patient had a Charcot foot deformity with a history of chronic foot ulcers and callouses. He had a chronic ulcer over the left first metatarsal cuneiform joint that had recently VOLUME 37, NUMBER 2, MARCH/APRIL 1998
145
healed to a Wagner grade 0 lesion. Prior conservative treatment, such as frequent visits for debridement, custommolded shoes, and soft inserts, had provided temporary relief. With the ulcer now healed, the patient requested surgical intervention to remove the plantar prominence in an attempt to avoid future ulceration. An exostectomy with arthrodesis of the first metatarsal cuneiform joint was scheduled. Clinical examination revealed a well-developed white male with a Wagner grade 0 lesion approximately 1.5 cm diameter over the left first metatarsal cuneiform joint. There was no erythema, on drainage, and only minimal edema without tenderness over the left first metatarsal cuneiform joint. A palpable exostosis on the plantar aspect of the medial cuneiform was evident. The vascular status was intact with normal finding. The neurological exam was abnormal. There was no lymphadenopathy present. Radiographs of the left foot revealed a prominent exostosis on the medial cuneiform with large osteophytes projecting from the talonavicular and navicular-cuboidal joints with degenerative changes and marked pes planus consistent with Charcot foot. The patient was taken to the operating room 4 days later. Preoperative laboratory results were within normal limits. He was given 1 g of cefazolin for prophylaxis prior to surgery. The surgery was performed under local anesthesia with monitored anesthesia care. The left foot was prepped and draped in the usual sterile fashion. A lazy-S incision was then made from proximal to distal across the medial arch and dorsal to the previous ulcerative lesion. The incision was carried deeper with care to expose adequately the first metatarsal-cuneiform joint. The exostosis was then removed. The articular cartilage was removed and two 4.5-mm cannulated screws were placed for fixation. The wound was flushed and closed in the usual manner. A bulky dressing was applied and followed by a posterior splint. There were no breaks in sterile technique throughout the procedure. The patient had been admitted to the hospital after the procedure and complained of nausea, vomiting, abdominal pain, diarrhea, and fever within the first 24 hours. The wound was inspected and there were no signs of infection. He received the usual battery of tests, such as complete blood cell count, urinalysis, blood cultures, and chest radiography. He also received treatment for nausea, vomiting, fluid loss, pain, and diabetes management. The sutures were removed to allow drainage and to obtain a wound specimen. As time progressed to the 3 postoperative day, the classic signs of infection appeared at the surgical site. Blood and wound cultures revealed M. morganii. The urinalysis was positive for bacteria and white blood cells. It is interesting that preoperative urinalysis did not show an increase in white blood cells. Empirically, the patient had been placed on gentamicin 146
THE JOURNAL OF FOOT & ANKLE SURGERY
for Gram-negative coverage since he had Gram-positive coverage prophylactically. Postoperatively, he received cephalexin, 250 mg p.o.q.i.d. Therapeutically, cefoteton was added to gentamicin. The organism was susceptible to both antibiotics. The
FIGURE 1
Infected surgical site several days after surgery.
FIGURE 2 Sequella of unhealed surgical site after infection by Morganella morganii.
patient was transferred to the medicine service on the day of admission to investigate his abdominal pain. The patient still received care from the podiatry staff. In addition to antibiotic therapy, aggressive wound care was begun. Daily irrigation and debridement with dressing changes were provided. The wound was necrotic at the anterior aspect of the tibialis anterior tendon and tracted next to the screw fixation. The screw fixation was then removed (Fig. 1). Radiographs were then taken and were negative for osteonecrosis. One-year follow-up revealed that the wound had not healed completely (Fig. 2). Discussion
M. morganii is an enteric, non-spore-forming, Gramnegative bacillus. It is a well-known part of normal flora. The organism is the etiologic agent for a variety of infections. Infections secondary to M. morganii reported in the literature include those of the urinary tract, soft tissue, and abdomen (9). It has also manifested as septic arthritis (12) and is proven to be a nosocomial pathogen (9). This case illustrates the need for prompt identification of pathogens in order to provide immediate treatment to avoid the devastating sequella associated with postoperative infections. These measures include appropriate laboratory tests such as complete blood cell count with differential and urinalysis. The surgical wound must be inspected for the first signs of infection. This may include releasing sutures as in our case. Results from the Gram stain as well as clinical suspicion, such as appearance of the tissue and previous use of antibiotics, will determine empiric therapy. Approximately 48 hours later, culture and susceptibility results will return and provide further guidance. Local wound care, such as daily debridement and copious irrigation, are as important as antibiotics. The concept is to clean the wound well daily so the antibiotics can penetrate the viable tissue and be more effective by having fewer organisms to combat. Timing of the dressing changes will be dependent on the amount of drainage. Packing the wound with sterile antimicrobial packing material is useful in absorbing drainage in large, deep wounds. Infection secondary to M. morganii is well treated by the appropriate antibiotic once it has been identified. It is susceptible to a number of drugs. These include second- and third-generation cephalosporins, antipseudomonal penicillin, fluoroquinolones, trimethoprimlsulfamethoxazole, and some aminoglycosides such as gentamicin and amikacin. It is also susceptible to imipenem and aztreonam. As mentioned above, susceptibility results will provide guidance in choosing an antibiotic as resistance becomes an increasing concern.
Susceptibility varies from region to region in treating bacterial infections. Summary
Infection of any type creates a serious situation which can be very debilitating to the patient if not managed properly. The patient in our case appeared to be free of infection prior to surgery. Symptoms were nearly immediate after surgery. Immunocompromised patients, such as those with diabetes mellitus, may be unable to mount a response. It is speculated by the authors that the patient had the M. morganii infection prior to the surgery and the stress of the surgical procedure proliferated the infectious process. The patient was given prompt infection management with immediate antibiotic coverage, yet there was much necrosis throughout the wound. The patient continues to have a nonhealed wound. References 1. Tachdilian, M. 0., Compere, E. L. Postoperative wound infections in orthopaedic surgery. Evaluation of prophylactic antibiotics. J. Int. cen. Surg. 28:979, 1957. 2. Williams, D. N. Antibiotic prophylaxis in bone and joint surgery. In Orthopaedic Infections - Diagnosis and Treatment, pp. 60- 74, edited by R. B. Gustillo, W.B. Saunders, Philadelphia, 1989. 3. Cruse, P. J. E. Wound infections - epidemiology and clinical characteristic. In Surgical Infectious Disease, 2nd ed., pp. 319-329 Appleton Lange, Norwalk, CT, 1988. 4. Burke, J. P. The effective period of preventive antibiotic action in experimental incisions and dermal lesions. Surgery 50: 161, 1961. 5. Fogelberg, E. V., Zitzman, E. K., Stinchfield, F. E. Prophylactic penicillin in orthopaedic surgery. J. Bone Joint Surg. 52-A:95, 1970. 6. Bowers, H. W., Wilson, F. c., Green, W. B. Antibiotic prophylaxis in experimental bone infection. J. Bone Joint Surg. 55-A:125l, 1973. 7. Boyd, R. J., Burke, J. P., Colton, T. A double-blind clinical trail of prophylactic antibiotics in hip fractures. J. Bone Joint Surg. 55A:125l, 1973. 8. Classen, D. C., Evans, R. S., Pestotnik, S. L., Hom, S. D., Menlove, R. L., Burke, J. P. The timing of prophylactic administration of antibiotics and the risk of surgical wound infection. N. Engl. 1. Med. 326:281, 1992. 9. Mulligan, M. E. In vitro activity of cefixime and six other agents against nosocomial pathogens of the Enterobacteriaceae family. Infection Control 8(6): 241, 1987. 10. Freeman, B. A. The enteric bacilli: Klebsiella, Enterobacter, Serratia, Proteus, Providentia, and Morganella, ch.20. In The Burrow Textbook of Microbiology, 22nd ed., p.483, W. B. Saunders, Philadelphia, 1985. 11. Silverblatt, F. J., Weinstein, R. Enterobacteriaceae, edited by Principles and Practice of Infectious Disease, pp. 1226-1236, G.L. Mandell, R.G. Douglas, Jr., and Bennett, 1. E., John Wiley, New York, 1985. 12. Schonwetter, R. S., Orson, F. M. Chronic Morganella morganii arthritis in an elderly patient. J. Clin. Microbiol. 26:7, 1988.
VOLUME 37, NUMBER 2, MARCH/APRIL 1998
147