JBJI Journal of Bone and Joint Infection JBJI J. Bone Joint Infect. 2206-3552 Ivyspring Göttingen, Germany 10.7150/jbji.16124 Acute Mono-Arthritis of the Knee: A Case Report of Infection with <em>Parvimonas Micra</em> and Concomitant Pseudogout Dietvorst Martijn 1 Roerdink Ramon 2 Leenders Alexander C.A.P. 2 Kiel Menno A. 3 A. L. Paul 2 Maastricht University, Maastricht, The Netherlands; Jeroen Bosch general hospital, 's-Hertogenbosch, The Netherlands; Erasmus Medical Centre, Rotterdam, The Netherlands. 01 10 2016 1 1 65 67 Copyright: © 2016 Martijn Dietvorst et al. 2016 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://jbji.copernicus.org/articles/1/65/2016/jbji-1-65-2016.html The full text article is available as a PDF file from https://jbji.copernicus.org/articles/1/65/2016/jbji-1-65-2016.pdf

<p class="p p-first-last" id="__p2"><em>Parvimonas micra</em> is a rare pathogen for septic arthritis and is known for its subacute onset. We report a case of acute arthritis of the knee caused by <em>P. micra</em> and pseudogout. Initially, calcium pyrophosphate crystals were found in the knee, which were successfully treated with a steroid injection. Only anaerobic cultures became positive. A 16S rRNA PCR-analysis was necessary to identify <em>P. micra </em>as causative agent, a method which is never described before in similar cases. The infection was treated with clindamycin for 6 weeks. This is the third case report of a septic arthritis caused by <em>P. micra</em> and the second which also reports concomitant pseudogout.</p>

 References Baghban A, Gupta S. Parvimonas micra: A rare cause of native joint septic arthritis. Case reports. Anaerobe. 2016;39:26–27. George IA, Pande A, Parsaei S. Delayed infection with Parvimonas micra following spinal instrumentation. Anaerobe. 2015;35:102–104. Gahier M, Cozic C, Bourdon S, Guimard T, Cormier G. Spinal infections caused by Parvimonas micra. Médecine et maladies infectieuses. 2015;45:397–400. Riesbeck K, Sanzén L. Destructive Knee Joint Infection Caused by Peptostreptococcus micros: Importance of Early Microbiological Diagnosis. J Clin Microbiol. 1999;37(8):2737–2739. [PMC free article] Pilmis B, Israel J, Le Monnier A, Mizrahi A. Spondylodiscitis due to anaerobic bacteria about a case of Parvimonas micra infection. Anaerobe. 2015;34:156–157. Tejera B, Riveros A, Martínez-Morillo M, Cañellas J. Septic Arthritis Associated to Gout and Pseudogout: The Importance of Arthrocenthesis. Reumatol Clin. 2014;10(1):61–62. Jones SL, Riordan JW, Glasgow AL, Botes J, Boutlis CS. Two cases of spondylodiscitis caused by Parvimonas micra. Intern Med J. 2015;45(10):1090–1. Baer PA, Tenenbaum J, Fam AG, Little H. Coexistent septic and crystal arthritis. J Rheumatol. 1986;13(3):604–607. Shah K, Spear J, Nathanson LA, McCauley J, Edlow JA. Does the presence of crystal arthritis rule out septic arthritis. J Emerg Med. 2007;32(1):23–26. Kalambokis GN, Christou L, Tsianos EV. Multiple myeloma presenting with an acute bacterial infection. Int J Lab Hematol. 2009;31(4):375–383.