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Ustilago Species as a Cause of Central Line-Related Blood Stream Infection
CASE REPORT
Ustilago Species as a Cause of Central Line-Related Blood Stream Infection Travea A. McGhie, MD, MPH, Thomas W. Huber, PhD, Christelle E. Kassis, MD and Chetan Jinadatha, MD, MPH
Abstract: Ustilago, commonly referred to as “corn smut,” rarely causes human disease. Serious clinical infections caused by Ustilago species have been sparsely reported in medical literature. In this study, a case of central line infection caused by Ustilago species is presented. Key Indexing Terms: Ustilago; Corn smut; Line infection; Fungemia. [Am J Med Sci 2013;345(3):254–255.]
T
he genus Ustilago consists of numerous species that have biotrophic relationship with wheat, corn and grass. Traditionally, criteria such as spore size, shape and morphology were used to classify these organisms, but recently, DNA methods have been used to further determine their genetic association.1 One of the most studied species is Ustilago maydis, a cause of maize smut disease. Studies of this dimorphic fungus have revealed several mechanisms of pathogenicity and virulence.2 To the best of our knowledge, not since 1995, has there been a reported case of serious clinical infection caused by Ustilago species.3 Here, we present another interesting case of central line infection caused by this organism.
CASE REPORT A 64-year-old man with a history significant for stage IV moderately differentiated adenocarcinoma of the colon who underwent sigmoid resection, and numerous chemotherapy regimens, presented to the emergency department 6 days after chemotherapy with a chief complaint of acute onset of weakness. On admission, he had low-grade temperature and leukocytosis. He was thought to have a urinary tract infection and was started on ciprofloxacin, and subsequently discharged. Five days later, the patient was asked to return when the aerobic blood cultures drawn from the Port-A-Cath site revealed yeast. On that admission, he was afebrile and his leukocytosis had improved. He was empirically started on a dosage of 100 mg of micafungin intravenously. On examination, the patient had a right subclavian Port-A-Cath that had been in place for approximately 18 months. The initial blood culture drawn through the Port-A-Cath was identified by the VITEK 2 system (BioMérieux Inc, Durham, NC) as Cryptococcus laurentii with resistance to echinocandins and variable minimum inhibitory concentrations to azoles (Table 1). Once sensitivities were known, the patient was switched to 400 mg of fluconazole orally. The Port-A-Cath was removed on the third day of hospitalization, and grew 6 colonies of coagulase-negative staphyFrom the Infectious Diseases Division (TAM), Scott & White Memorial Hospital, Temple, Texas; Departments of Microbiology (TWH) and Medicine (CEK), and Infectious Diseases Division (CJ), Central Texas Veterans Health Care System, Temple, Texas. Submitted June 20, 2012; accepted in revised form August 15, 2012. The authors have no financial or other conflicts of interest to disclose. Correspondence: Chetan Jinadatha, MD, MPH, Infectious Diseases Division, Central Texas Veterans Health Care System, 1901 South Veterans Memorial Drive, Temple, TX 76504 (E-mail: [email protected]).
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lococci and 1 colony of yeast. The yeast was similar to the earlier isolate. The colonies were dark and developed a diffuse reddish-brown pigment over time on Sabaroud agar, and on India ink preparation, there was a slime layer and not a capsule (because it was dissolved by the preparation). The morphology on the culture plates was suspicious for Monascus ruber. Our microbiologist suspected otherwise. This was later diagnosed to be the smut fungus of Ustilago species by the Audie Murphy Veterans Administration/University of Texas at San Antonio fungal reference laboratory in San Antonio, Texas (Figure 1). The clinical course included an ophthalmology examination that revealed no evidence of endophthalmitis. A transesophageal echocardiogram revealed no evidence of endocarditis. A computed tomography scan of the abdomen and pelvis, with and without contrast, did not show evidence of intra-abdominal or pelvic abscess. Repeat blood cultures after removal of the central venous catheter were negative. He was subsequently discharged after completing a 14-day course of fluconazole, and did well, with no recurrences to date (6 months).
DISCUSSION Ustilago species has been reported to cause immediate skin sensitivity, asthma and hypersensitivity pneumonitis in India and Japan.3–6 In 2008, Lin et al7 reported a related species, Pseudozyma aphidis, causing central venous catheter infection in a child with short gut syndrome. Review of the central venous catheter fungemia cases in comparison with our patient revealed similar characteristics.3,7 All 3 patients had surgical bowel manipulations before being diagnosed with fungemia. Additionally, there was no history of corn or corn product exposure in our patient. He had never been to Mexico and rarely dined outside his home. Upon presentation, our patient had recently completed chemotherapy, but was not neutropenic. Potential portals of entry include cutaneous sources versus his gastrointestinal tract. Management included the removal and culture of the central venous catheter and the use of fluconazole. The rarity of the disease in humans has not allowed minimum inhibitory concentration breakpoints for susceptibility testing to TABLE 1. MICs of Ustilago species to various antifungals Antifungal MICs (mg/mL) Fluconazole Itraconazole Flucytosine Posaconazole Voriconazole Caspofungin Anidulafungin Micafungin Amphotericin B
0.5 0.023 32 0.03 0.015 8 8 8 0.12
MIC, minimum inhibitory concentration.
The American Journal of the Medical Sciences
Volume 345, Number 3, March 2013
Central Line Infection Related to Ustilago Species
a relationship between central line venous infections with this species and surgical abdominal manipulation. As medicine and technology advance, so will the need for susceptibility data and therapeutic modalities geared toward these pathogens. REFERENCES 1. Menzies JG, Bakkeren G, Matheson F, et al. Use of inter-simple sequence repeats and amplified fragment length polymorphisms to analyze genetic relationships among small grain-infecting species of ustilago. Phytopathology 2003;93:167–75. 2. Giasson L, Kronstad JW. Mutations in the myp1 gene of Ustilago maydis attenuate mycelial growth and virulence. Genetics 1995;141: 491–501.
FIGURE 1. Lactophenol cotton blue tease preparations of Ustilago, photographed at 10003, showing pleomorphic budding yeast.
be established. Additionally, it is pertinent to note that the patient was empirically started on micafungin, and this organism was classified as resistant.
CONCLUSIONS The pathogenic potential of Ustilago species in humans is becoming more evident with the accumulation of reports. Our case, when compared with the previous reports, postulates
Ó 2012 Lippincott Williams & Wilkins
3. Patel R, Roberts GD, Kelly DG, et al. Central venous catheter infection due to Ustilago species. Clin Infect Dis 1995;21:1043–4. 4. Teo LH, Tay YK. Ustilago species infection in humans. Br J Dermatol 2006;155:1096–7. 5. Singh AB, Kumar P. Common environmental allergens causing respiratory allergy in India. Indian J Pediatr 2002;69:245–50. 6. Yoshida K, Suga M, Yamasaki H, et al. Hypersensitivity pneumonitis induced by a smut fungus Ustilago esculenta. Thorax 1996;51:650–1; discussion 656–7. 7. Lin SS, Pranikoff T, Smith SF, et al. Central venous catheter infection associated with Pseudozyma aphidis in a child with short gut syndrome. J Med Microbiol 2008;57(pt 4):516–8.
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Ustilago Species as a Cause of Central Line-Related Blood Stream Infection Travea A. McGhie, MD, MPH, Thomas W. Huber, PhD, Christelle E. Kassis, MD and Chetan Jinadatha, MD, MPH
Abstract: Ustilago, commonly referred to as “corn smut,” rarely causes human disease. Serious clinical infections caused by Ustilago species have been sparsely reported in medical literature. In this study, a case of central line infection caused by Ustilago species is presented. Key Indexing Terms: Ustilago; Corn smut; Line infection; Fungemia. [Am J Med Sci 2013;345(3):254–255.]
T
he genus Ustilago consists of numerous species that have biotrophic relationship with wheat, corn and grass. Traditionally, criteria such as spore size, shape and morphology were used to classify these organisms, but recently, DNA methods have been used to further determine their genetic association.1 One of the most studied species is Ustilago maydis, a cause of maize smut disease. Studies of this dimorphic fungus have revealed several mechanisms of pathogenicity and virulence.2 To the best of our knowledge, not since 1995, has there been a reported case of serious clinical infection caused by Ustilago species.3 Here, we present another interesting case of central line infection caused by this organism.
CASE REPORT A 64-year-old man with a history significant for stage IV moderately differentiated adenocarcinoma of the colon who underwent sigmoid resection, and numerous chemotherapy regimens, presented to the emergency department 6 days after chemotherapy with a chief complaint of acute onset of weakness. On admission, he had low-grade temperature and leukocytosis. He was thought to have a urinary tract infection and was started on ciprofloxacin, and subsequently discharged. Five days later, the patient was asked to return when the aerobic blood cultures drawn from the Port-A-Cath site revealed yeast. On that admission, he was afebrile and his leukocytosis had improved. He was empirically started on a dosage of 100 mg of micafungin intravenously. On examination, the patient had a right subclavian Port-A-Cath that had been in place for approximately 18 months. The initial blood culture drawn through the Port-A-Cath was identified by the VITEK 2 system (BioMérieux Inc, Durham, NC) as Cryptococcus laurentii with resistance to echinocandins and variable minimum inhibitory concentrations to azoles (Table 1). Once sensitivities were known, the patient was switched to 400 mg of fluconazole orally. The Port-A-Cath was removed on the third day of hospitalization, and grew 6 colonies of coagulase-negative staphyFrom the Infectious Diseases Division (TAM), Scott & White Memorial Hospital, Temple, Texas; Departments of Microbiology (TWH) and Medicine (CEK), and Infectious Diseases Division (CJ), Central Texas Veterans Health Care System, Temple, Texas. Submitted June 20, 2012; accepted in revised form August 15, 2012. The authors have no financial or other conflicts of interest to disclose. Correspondence: Chetan Jinadatha, MD, MPH, Infectious Diseases Division, Central Texas Veterans Health Care System, 1901 South Veterans Memorial Drive, Temple, TX 76504 (E-mail: [email protected]).
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lococci and 1 colony of yeast. The yeast was similar to the earlier isolate. The colonies were dark and developed a diffuse reddish-brown pigment over time on Sabaroud agar, and on India ink preparation, there was a slime layer and not a capsule (because it was dissolved by the preparation). The morphology on the culture plates was suspicious for Monascus ruber. Our microbiologist suspected otherwise. This was later diagnosed to be the smut fungus of Ustilago species by the Audie Murphy Veterans Administration/University of Texas at San Antonio fungal reference laboratory in San Antonio, Texas (Figure 1). The clinical course included an ophthalmology examination that revealed no evidence of endophthalmitis. A transesophageal echocardiogram revealed no evidence of endocarditis. A computed tomography scan of the abdomen and pelvis, with and without contrast, did not show evidence of intra-abdominal or pelvic abscess. Repeat blood cultures after removal of the central venous catheter were negative. He was subsequently discharged after completing a 14-day course of fluconazole, and did well, with no recurrences to date (6 months).
DISCUSSION Ustilago species has been reported to cause immediate skin sensitivity, asthma and hypersensitivity pneumonitis in India and Japan.3–6 In 2008, Lin et al7 reported a related species, Pseudozyma aphidis, causing central venous catheter infection in a child with short gut syndrome. Review of the central venous catheter fungemia cases in comparison with our patient revealed similar characteristics.3,7 All 3 patients had surgical bowel manipulations before being diagnosed with fungemia. Additionally, there was no history of corn or corn product exposure in our patient. He had never been to Mexico and rarely dined outside his home. Upon presentation, our patient had recently completed chemotherapy, but was not neutropenic. Potential portals of entry include cutaneous sources versus his gastrointestinal tract. Management included the removal and culture of the central venous catheter and the use of fluconazole. The rarity of the disease in humans has not allowed minimum inhibitory concentration breakpoints for susceptibility testing to TABLE 1. MICs of Ustilago species to various antifungals Antifungal MICs (mg/mL) Fluconazole Itraconazole Flucytosine Posaconazole Voriconazole Caspofungin Anidulafungin Micafungin Amphotericin B
0.5 0.023 32 0.03 0.015 8 8 8 0.12
MIC, minimum inhibitory concentration.
The American Journal of the Medical Sciences
Volume 345, Number 3, March 2013
Central Line Infection Related to Ustilago Species
a relationship between central line venous infections with this species and surgical abdominal manipulation. As medicine and technology advance, so will the need for susceptibility data and therapeutic modalities geared toward these pathogens. REFERENCES 1. Menzies JG, Bakkeren G, Matheson F, et al. Use of inter-simple sequence repeats and amplified fragment length polymorphisms to analyze genetic relationships among small grain-infecting species of ustilago. Phytopathology 2003;93:167–75. 2. Giasson L, Kronstad JW. Mutations in the myp1 gene of Ustilago maydis attenuate mycelial growth and virulence. Genetics 1995;141: 491–501.
FIGURE 1. Lactophenol cotton blue tease preparations of Ustilago, photographed at 10003, showing pleomorphic budding yeast.
be established. Additionally, it is pertinent to note that the patient was empirically started on micafungin, and this organism was classified as resistant.
CONCLUSIONS The pathogenic potential of Ustilago species in humans is becoming more evident with the accumulation of reports. Our case, when compared with the previous reports, postulates
Ó 2012 Lippincott Williams & Wilkins
3. Patel R, Roberts GD, Kelly DG, et al. Central venous catheter infection due to Ustilago species. Clin Infect Dis 1995;21:1043–4. 4. Teo LH, Tay YK. Ustilago species infection in humans. Br J Dermatol 2006;155:1096–7. 5. Singh AB, Kumar P. Common environmental allergens causing respiratory allergy in India. Indian J Pediatr 2002;69:245–50. 6. Yoshida K, Suga M, Yamasaki H, et al. Hypersensitivity pneumonitis induced by a smut fungus Ustilago esculenta. Thorax 1996;51:650–1; discussion 656–7. 7. Lin SS, Pranikoff T, Smith SF, et al. Central venous catheter infection associated with Pseudozyma aphidis in a child with short gut syndrome. J Med Microbiol 2008;57(pt 4):516–8.
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