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 Table of Contents  
Year : 2020  |  Volume : 22  |  Issue : 1  |  Page : 50-52

Post-operative sternal wound infection due to Nocardia cyriacigeorica after open-heart surgery: Two case reports

1 Department of Microbiology, CARE Hospital, Hyderabad, Telangana, India
2 Department of Cardiothoracic Surgery, CARE Hospital, Hyderabad, Telangana, India

Date of Submission27-May-2020
Date of Decision17-Jul-2020
Date of Acceptance22-Jun-2020
Date of Web Publication13-Aug-2020

Correspondence Address:
Dr. Jhansi Vani Devana
Department of Microbiology, CARE Hospital, Road No. 1, Banjara Hills, Hyderabad - 500 034, Telangana
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jacm.jacm_14_20

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Surgical site infection is the second most common nosocomial infection in healthcare facilities. Open-heart surgery is a clean surgery, and sternal wound infection after open-heart surgery has a great impact on the patient both psychologically and financially. Sternal wound infections are preventable infections if stringent infection control practices are followed. Sternal wound infection after cardiac surgery due to Nocardia is very rare. Nocardia species are aerobic actinomycetes ubiquitously found in soil and aquatic habitats. Nocardia are beaded Gram-positive, branching rods that are partially acid fast. We report two cases of post-operative sternal wound infection caused by Nocardia.

Keywords: Nocardia cyriacigeorica, open-heart surgery, sternal wound

How to cite this article:
Devana JV, Gutti R. Post-operative sternal wound infection due to Nocardia cyriacigeorica after open-heart surgery: Two case reports. J Acad Clin Microbiol 2020;22:50-2

How to cite this URL:
Devana JV, Gutti R. Post-operative sternal wound infection due to Nocardia cyriacigeorica after open-heart surgery: Two case reports. J Acad Clin Microbiol [serial online] 2020 [cited 2022 Jan 27];22:50-2. Available from: https://www.jacmjournal.org/text.asp?2020/22/1/50/291887

  Introduction Top

Nosocomial sternal wound infection due to Nocardia is very rare. In South India, one case of Nocardia asteroides mediastinitis complicating coronary artery bypass surgery was reported by Verghese et al. Nocardia has been reported to cause surgical site infections (SSI) in two outbreaks after cardiac transplant and after open-heart surgery.[1] Nocardia are Gram-positive branching bacilli that are partially acid fast and are generally slow growing and belong to the family Nocardiaceae. Nocardia are aerobic actinomycetes ubiquitously found in soil and aquatic habitats. Approximately 30 Nocardia species are known to cause human infections. They are known to cause infections as opportunistic pathogens in immunocompromised patients and human immunodeficiency virus-infected patients. Nocardia usually manifests as an acute or subacute or chronic infection. Its primary target organ is the lung. Humans acquire infection by inhalation or inoculation. Nosocomial transmission has also been reported. Mortality appears to correlate with causative species and the site of infection. Laboratory identification of Nocardia is challenging and time consuming. It is extremely difficult to make precise species-level identification in clinical laboratories. Wallace et al. reported on species indicative differences in antimicrobial susceptibility patterns.[2] However, this methodology is time-consuming labour-intense and it does not provide a definitive identification because patterns are shared between species. Molecular methods such as 16S rRNA and hsp 65 gene sequence analysis are useful for rapid and accurate identification of species.[3]

  Case Reports Top

Case report 1

A 70-year-old male patient, known case of chronic kidney disease and Type II diabetes, admitted with inferior wall myocardial infarction and severe mitral valve regurgitation. He underwent coronary artery bypass surgery, mitral valve replacement and tricuspid valve repair. The surgery was uneventful and the patient was discharged on the 10th post-operative day. He presented to our outpatient department after one month with a complaint of serosanguinous discharge from a sternal wound [Figure 1]. Pus was collected in a sterile container. No granules are seen in the pus. Gram stain of pus showed Gram-positive thin, branched filaments. Modified acid-fast stain showed weakly acid-fast branched filaments [Figure 2]. Pus sample was inoculated on to blood agar, MacConkey and Sabouraud Dextrose Agar (SDA) and incubated at 35°C. After three days of incubation, blood agar showed white dry colonies [Figure 3]. As we do not have the facility to identify the species, culture plate was sent to the referral laboratory and the organism was identified as Nocardia cyriacigeorgica; initially, the patient was treated with Linezolid, but he developed Linezolid-related side effects. Then, the drug was discontinued and Cotrimoxazole was started for which he showed a significant clinical improvement [Figure 4].
Figure 1: Sternal wound before treatment

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Figure 2: Modified AFB staining-weakly acid fast filamentous forms

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Figure 3: White dry colonies on blood agar

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Figure 4: Healing sternal wound

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Case report 2

A 54-year-old female patient admitted with a history of chronic rheumatic heart disease. All laboratory investigations are within normal limits except two-dimensional echocardiography which showed severe mitral regurgitation and moderate tricuspid regurgitation. Transoesophageal echocardiography was done which did not reveal any intra-cavitatory clot/vegetations on the valve. She underwent mitral valve replacement and tricuspid valve repair. The post-operative hospital course was uneventful. She was discharged on the 7th post-operative day. Six months after surgery, she came to the outpatient department with a complaint of mild discharge from the sternal wound. The discharge was collected and sent for culture. Gram stain done on the pus showed Gram-positive, branched filaments. Simultaneously, pus was inoculated on to the blood agar, MacConkey agar and SDA and incubated at 35°C. After 72 h of incubation, white dry colonies are seen on the blood agar plate. The culture plate was sent to a referral laboratory for identification which was identified as N. cyriacigeorgica, and Cotrimoxazole was started. She showed clinical improvement. In the follow-up visits, the wound showed signs of healing.

  Discussion Top

Nocardial infections are divided into (1) primary cutaneous nocardiosis, (2) disseminated disease and (3) actinomycetoma. Deep inoculation into subcutaneous tissue leads to mycetoma formation, whereas superficial inoculation leads to pustule or abscess formation. Sometimes, the infection spreads through lymphatics causing lymphocutaneous infection.[4]

Nocardiosis has been reported worldwide. Approximately 500–1000 cases of nocardiosis are reported in the US each year. There are limited data on the incidence of Nocardia infection in India. Primary cutaneous Nocardiosis occurs by direct implantation of Nocardia from soil. It can also be transmitted from person to person. Peter et al. reported a case of sternal wound infection due to Nocardia farcinica following open-heart surgery. They demonstrated that Nocardia can be transmitted from the soil surface to healthcare workers' hands to the patients by molecular method.[4] Jangla and Machh reported a case of post-operative wound infection caused by Nocardia species after modified radical mastectomy.[5] Verghese et al. reported a case of N. asteroides mediastinitis complicating coronary artery bypass surgery. They identified the organism as N. asteroides by biochemical reactions and was confirmed by the Centre for Disease Control, Atlanta.[6] In our case, we identified species by gene sequencing as N. cyriacigeorgica in both the patients. N. cyriacigeorgica is a common environmental organism and was first reported in 2001 from a patient with chronic bronchitis by chemotaxonomic and 16S RNA sequencing by Yassin et al.[7] They demonstrated that the isolate from the bronchial secretions belongs to the genus Nocardia, but it belongs to a new species and N. cyriacigeorgici sp.nov. name was proposed to that isolate. Cloud et al. reported that most (53%) of the N. asteroides complex isolates gave perfect matches to N. cyriacigeorgica, while the remaining isolates were split among N. asteroides drug group IV and N. abscessus. using partial 16S ribosomal DNA sequencing.[8] Conville andWitebsky reported that organisms designated as N. asteroids drug pattern Type VI are members of the species N. cyricigeorgica using DNA–DNA hybridisation.[9] It has been isolated from clinical samples such as septicaemia, brain abscess, pleural empyema and keratits [10]. Post-operative sternal wound infection due to N. cyiacigeorgica is very rarely reported. To our knowledge, this is one of few case reports of SSI due to N. cyriacigeorgica, and both the patients showed a significant clinical improvement. Surgeons should be well aware of nocardial infections as it causes significant morbidity and mortality in those patients who have Nocardia SSI. High suspicion is important to inform the laboratory to keep the plates for at least 72 h of incubation.

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.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Wenger PN, Brown JM, McNeil MM, Jarvis WR. Nocardia farcinica sternotomy site infections in patients following open heart surgery. J Infect Dis 1998;178:1539-43.  Back to cited text no. 1
Wallace RJ Jr., Steele LC, Sumter G, Smith JM. Antimicrobial susceptibility patterns of Nocardia asteroides. Antimicrob. Agents Chemother 1988;32:1776-9.  Back to cited text no. 2
Schlaberg R, Huarddd RC, Phyllis-Latta. Nocardia cyriageorgica, an emerging pathogen in the United States. J Clin Microbiol 2008;46:265-73.  Back to cited text no. 3
Saoji VA, Saoji SV, Gadegone RW, Menghani PR. Primary cutaneous nocardiosis. Indian J Dermatol 2012:57:404-6.  Back to cited text no. 4
Jangla SM, Machh BS. Postoperative wound infection caused by Nocardia species. JKIMSU 2018;7.  Back to cited text no. 5
Verghese S, Kurian VM, Maria CF, Padmaja P, Elizabeth SJ, Cherian KM. Nocardia asteroides mediatinitis complicating coronary artery bypass surgery. JAPI 2003;51:1009-10.  Back to cited text no. 6
Yassin AF, Rainey FA, Steiner U. Nocardia cyriacigeogica sp. Nov. Int J Syst Evol Microbiol 2001;51:1419-23.  Back to cited text no. 7
Cloud JL, Patricia S, Conville, AC, Harmsen D, Witebsky FG, Carroll KC. Evaluation of partial 16S ribosomal DNA sequencing for identification of Nocardia species by using the MicroSeq 500 system with an expanded database. J Clin Microbiol 2004;42:578-84.  Back to cited text no. 8
Conville PS, Witebsky FG. Organisms designated as Nocardia asteroids drug pattern VI are members of the species Nocardia cyriacigeorgica. J Clini Microbiol 2007;45:2257-9.  Back to cited text no. 9
Lalitha P, Tiwari M, Prajna NV, Prakakash K, Srinivasan M. Nocardial keratitis: Species, drug sensitivity, and clinical correlation. Cornea 2007;26:255-9.  Back to cited text no. 10


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


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