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 Table of Contents  
CASE REPORT
Year : 2022  |  Volume : 24  |  Issue : 2  |  Page : 87-89

Fungal sternal wound infection following coronary artery bypass graft surgery – A rare case of surgical site infection


Department of Microbiology, Jubilee Mission Medical College and Research Institute, Thrissur, Kerala, India

Date of Submission04-Oct-2022
Date of Acceptance23-Nov-2022
Date of Web Publication13-Dec-2022

Correspondence Address:
Rosmi Jose
Department of Microbiology, Jubilee Mission Medical College, Thrissur - 680 005, Kerala
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jacm.jacm_19_22

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  Abstract 


Sternal wound infections following cardiac surgery by fungus are not common. Here, we report a case of Aspergillus sternal wound infection following coronary artery bypass graft (CABG) surgery. Elderly diabetic and hypertensive female patient presented with non-healing chest wound three and half months after CABG surgery. Aspergillus flavus was isolated from the pus sample from the sternal wound site. The patient was treated with surgical debridement and oral voriconazole for six weeks and she became asymptomatic and the wound completely healed on follow-up.

Keywords: Aspergillus flavus, post-coronary artery bypass graft, sternal wound infection


How to cite this article:
Jose R, Babu I, Valsan C. Fungal sternal wound infection following coronary artery bypass graft surgery – A rare case of surgical site infection. J Acad Clin Microbiol 2022;24:87-9

How to cite this URL:
Jose R, Babu I, Valsan C. Fungal sternal wound infection following coronary artery bypass graft surgery – A rare case of surgical site infection. J Acad Clin Microbiol [serial online] 2022 [cited 2023 Jan 28];24:87-9. Available from: https://www.jacmjournal.org/text.asp?2022/24/2/87/363473




  Introduction Top


Surgical site infections following coronary artery bypass graft (CABG) procedures pose a substantial burden on patients and health-care systems, particularly from serious infections at sternal sites. Sternal wound infections with osteomyelitis and costochondritis are not uncommon after cardiac surgery.[1] They increase the morbidity, mortality and hospitalisation days after cardiac surgery.[2] Sternal wound infection by a fungus is a rarity, and it warrants a correct diagnosis followed by specific treatment. We report a case of Aspergillus sternal wound infection with costochondritis following CABG surgery.


  Case Report Top


A 79-year-old, known diabetic and hypertensive thin, built female was admitted to the cardiology department with chest pain on 9th June 2021. She was diagnosed to have inferior wall MI and underwent open heart CABG surgery two days later. The post-operative period was uneventful and the patient was discharged one week after surgery. Three and half months later, she presented with complaints of low-grade fever and intense pain over the lower anterior chest wall, associated with mild serous discharge from the sternotomy scar. On examination, the lower anterior chest wall was inflamed and tender, with a punctate sinus opening in the lower aspect of the sternal scar, discharging minimal serous fluid [Figure 1]. Laboratory test results at the time of admission were as follows haemoglobin 9.5 gm%, white blood cell count 7280/μL, neutrophils 66%, lymphocytes 26%, eosinophils 6% and monocytes 2%. Computed tomography (CT) scan of the chest showed a small sinus tract at the midline anterior chest wall and features suggestive of infection in the right 4th to 6th costal cartilage. The patient was managed surgically with wound debridement, sternal wire removal and removal of four right lower costal cartilages under general anaesthesia following which the wound was kept open. The debrided pus sample, along with removed cartilage was sent to microbiology laboratory for bacterial culture and for histopathological examination. The patient was started on injections Ciprofloxacin, Gentamicin and oral Linezolid. The pus sample was inoculated on blood agar and MacConkey agar and incubated aerobically at 37°C. Gram staining of the sample showed only scanty pus cells. The culture plates did not show any growth after overnight incubation and they were further incubated for one week. On the fifth day of incubation, fungal growth was seen in the blood agar plate at the site of inoculation [Figure 2]. Lactophenol cotton blue preparation was done, and the fungal growth was identified as Aspergillus flavus (species confirmed by the mycology division at PGI Chandigarh) [Figure 3]. Later, the same growth was obtained on subsequent inoculation of the sample onto Sabouraud dextrose agar. Histopathological examination (Gomori methanamine silver [GMS] staining) of the debrided tissue also showed septate fungal hyphae in cartilage [Figure 4]. Simultaneously, case was discussed with the surgeon and the patient was started on oral voriconazole 200 mg twice a day. Sternal wound resuturing was done on the 13th day of admission. The patient was discharged on the 17th day of admission; she was pain-free with a healthy-looking wound at the time of discharge. She was treated with a six-week course of oral voriconazole. The patient became completely asymptomatic and the wound completely healed on the subsequent follow-up visits.
Figure 1: Sternal wound site

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Figure 2: Fungal growth on blood agar

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Figure 3: LPCB mount. LPCB: Lactophenol Cotton Blue

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Figure 4: Histopathology examination GMS staining. GMS: Gomori methanamine silver stain

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  Discussion Top


Fungal wound infections are unusual after cardiac surgery, with Aspergillus species being the most frequently identified causative organism.[3] These infections are usually caused by Staphylococcus spp. or Gram-negative bacilli such as Pseudomonas aeruginosa and Enterobacteriaceae.[4],[5] Although post-operative invasive aspergillosis (POIA) classically occurs in immunocompromised patients, increasing numbers are being reported in the immunocompetent also. Solid organ transplantation, neutropenia and chronic lung diseases are the common risk factors identified for POIA. Chronic steroid therapy, HIV infection and uncontrolled diabetes mellitus increases the risk of these infections as well.[3],[6] In our case, diabetes mellitus was the only risk factor identified, but it was under control during the pre- and post-operative period. Many studies have linked post-operative aspergillosis with the poorly maintained ventilation system in the operation theatre.[3] However, in this case, surgery was conducted in a well-maintained cardiac operation theatre (OT) with high-efficiency particulate air (HEPA) filter.

Fungal infections typically present a few months after surgery; however, the incubation period can vary from one week to a year.[3],[6] Being paucisymptomatic and rarity of infection, a high index of suspicion is needed for the timely diagnosis of fungal wound infections. Deep fungal infections are usually identified by diagnostic images and mycological studies, which include biopsy for pathological study and microbiological isolation of the fungus.[7] In the present case, prolonged incubation of the routine bacterial cultures was kept by noting the history of delayed onset post-operative wound infection and anticipating an unusual pathogen.

There have been only a few cases of Aspergillus sternal wound infection reported so far in the literature. Aspergillus flavus followed by Aspergillus fumigatus was accounted for most of these reported cases.[8] Thorough surgical debridement supplemented by antifungal therapy is mandatory in the treatment of these infections. Various antifungal medications were successfully used for treatment in different centres, including combination therapy with Amphotericin B and itraconazole/voriconazole or monotherapy with azoles.[6],[8],[9] The Infectious Diseases Society of America recommends the use of voriconazole, a broad-spectrum second-generation triazole antifungal drug, due to its tolerance, greater effectiveness and lower toxicity.[10] The overall duration of treatment required is unclear, but at least 6–8 weeks of antifungal therapy has been recommended and should depend on clinical response.


  Conclusion Top


The present case report and review of literature emphasises the importance of considering aspergillosis in the differential diagnosis of slowly progressive, but destructive and culture-negative post-operative wound infections. A good communication between surgeons and microbiologists can facilitate the prompt diagnosis and early initiation of the right treatment for these unusual surgical site infections.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Acknowledgements

The authors would like to thank Dr. John E V, HOD, Department of Cardiovascular thoracic surgery and Dr. Lincy Joseph, HOD, Department of Pathology.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Salehi Omran A, Karimi A, Ahmadi SH, Davoodi S, Marzban M, Movahedi N, et al. Superficial and deep sternal wound infection after more than 9000 coronary artery bypass graft (CABG): Incidence, risk factors and mortality. BMC Infect Dis 2007;7:112.  Back to cited text no. 1
    
2.
Borger MA, Rao V, Weisel RD, Ivanov J, Cohen G, Scully HE, et al. Deep sternal wound infection: Risk factors and outcomes. Ann Thorac Surg 1998;65:1050-6.  Back to cited text no. 2
    
3.
Pasqualotto AC, Denning DW. Post-operative aspergillosis. Clin Microbiol Infect 2006;12:1060-76.  Back to cited text no. 3
    
4.
Chaudhuri A, Shekar K, Coulter C. Post-operative deep sternal wound infections: Making an early microbiological diagnosis. Eur J Cardiothorac Surg 2012;41:1304-8.  Back to cited text no. 4
    
5.
Moinipoor AA, Abbasi M, Amouzeshi A, Esfahanizadeh J, Amini S. Deep sternal wound infection following cardiac surgery epidemiology and causative germs. J Surg Trauma 2013;1:21-5.  Back to cited text no. 5
    
6.
Asare KA, Jahng M, Pincus JL, Massie L, Lee SA. Sternal osteomyelitis caused by Aspergillus fumigatus following cardiac surgery: Case and review. Med Mycol Case Rep 2012;2:4-6.  Back to cited text no. 6
    
7.
Patterson TF. Aspergillus species. In: Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Philadelphia (PA): Elsevier Inc.; 2014. p. 2895-908.  Back to cited text no. 7
    
8.
Routray C, Nwaigwe C. Sternal osteomyelitis secondary to Aspergillus fumigatus after cardiothoracic surgery. Med Mycol Case Rep 2020;28:16-9.  Back to cited text no. 8
    
9.
Siciliano RF, Waisberg DR, Samano MN, Leite PF, Tuma Júnior P, Barreiro GC, et al. Poststernotomy aspergillosis: Successful treatment with voriconazole, surgical debridement and vacuum-assisted closure therapy. Clinics (Sao Paulo) 2012;67:297-9.  Back to cited text no. 9
    
10.
Walsh TJ, Anaissie EJ, Denning DW, Herbrecht R, Kontoyiannis DP, Marr KA, et al. Treatment of aspergillosis: Clinical practice guidelines of the infectious diseases society of America. Clin Infect Dis 2008;46:327-60.  Back to cited text no. 10
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4]



 

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