Cases in clinical microbiology.
The case description on this page and its follow-up discussion presented elsewhere in this issue is the 18th in a series of articles presenting clinical microbiology cases that will appear in this journal. Readers should study the case description below and formulate their own answers to the questions posed. After coming up with a solution to the problem, turn to page 68 in this issue and read the Case Follow-up and Discussion. This is followed by Questions for STEP Participants on page 71.
Joel E. Mortensen, PhD, MLT(AMT), Series Editor
Case Description: A 15-year-old male with a history of cystic fibrosis and allergic bronchopulmonary aspergillosis, presented in September of 2009 to the Cystic Fibrosis Clinic of Cincinnati Children's Hospital for routine follow-up. At presentation, the patient complained of decreased exercise tolerance and was found to have decreased functional expiratory volume (FEV1) to 86%, relative to his baseline (over 100%), on pulmonary function tests performed. At the time of this visit, October 2009, he again presented with an increasing productive cough producing thick mucus and an associated shortness of breath. Sputum culture obtained at that time grew Gram-negative bacilli, as well as Staphylococcus aureus. Previous respiratory cultures from this patient grew different bacterial pathogens including Inquilinus limosus and Achromobacterxylosoxidans (Alcaligines).The patient was treated in accordance with the reported susceptibility pattern with intravenous meropenem (1000 mg, every 8 hours for 16 days), and oral doxycycline (100 mg, every 12 hours for 14 days).
In the laboratory, the sputum was cultured on 5% sheep blood, chocolate, and MacConkey agar, as well as PC agar and chocolate agar with bacitracin. The media was incubated at 35[degrees] in 5% C[O.sub.2] for 24 hours. Following incubation, multiple 0.3 cm in diameter, whitish-grey, non-hemolytic colonies grew predominantly on chocolate agar. Very few colonies were noted on 5% sheep blood agar, and there were several colonies of nonlactose fermenting Gram-negative bacilli on MacConkey agar. The organism did not grow on PC agar or chocolate agar with bacitracin. Subsequently, identification was attempted using the Remel Rapid NF testing kit for glucose-non-fermenting gram-negative bacteria. The result was listed as inconclusive, but most consistent with Pseudomonas aeruginosa or Burkholderia cepacia. Should this identification be believed? What should be done with the isolate at this point?
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|Author:||Mortensen, Joel E.|
|Publication:||Journal of Continuing Education Topics & Issues|
|Date:||Apr 1, 2010|
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