![]() ![]() striatum, which can be pathogenic in vulnerable individuals. This was done to rule out Corynebacterium urealyticum, C. Coryneform species are usually considered contaminants, however the presence of this organism in three consecutive vials prompted further identification by VITEK-2 Compact 60 (AES software) (bioMerieux, Inc., USA) automated system using the VITEK Anaerobe Identification (ANI) card. Catalase test was positive, a characteristic commonly exhibited by both Coryneform species and Brucella species. ![]() By 48 hrs, good growth was observed on a blood agar plate. After 24 hour- incubation on blood agar plates, tiny growth was observed on the primary streaking, further suggesting Coryneform isolates as many Coryneform species are characterized by slow growth. Coryneform species, usually interpreted as contaminants of unknown clinical importance, were suspected and a preliminary report of “Gram-positive bacilli” was generated and reported. ![]() Pleomorphic Gram-positive bacteria were isolated from the blood culture, ranging in shape from round cocci to short, thin rods bacilli Fig. After four days, all three aerobic blood culture vials were flagged positive-by Bactec FX ® system. Three sets of aerobic and anaerobic blood cultures were collected. After one week of hospitalization, ceftriaxone was discontinued and the patient was discharged on doxycycline and rifampin. On admission, he was given IV ceftriaxone later on, doxycycline and rifampin were added to his treatment. The patient prior to these symptoms went to the desert for the school vacations, where he had contact with animals. Blood culture turned out to be positive for gram positive cocci in pairs and chains and the patient was called back for admission. The patient was given IV fluids, tests were performed and he was sent home. In February 2015, a 12-year-old boy presented to the Emergency Room with fever, vomiting and diarrhea. Here we report two cases from an acute-care facility in which initial misinterpretation of Gram staining in blood cultures led to delays in identification of Brucella and A. Primary Gram stain reporting as Gram-positive or Gram-variable can lead to misidentification of these slow-growing Gram-negative coccobacilli and a misidentification of contaminating Coryneform species. It is also one of the common laboratory-acquired infections worldwide. Brucellosis is rare in developed countries, however this zoonotic disease is of special concern in countries where there is significant importation of livestock, such as Saudi Arabia. Other Gram-negative bacteria which are vulnerable to misidentification are Brucella species. baumannii is limited and suggest emergence of multi-drug resistant (MDR), nosocomial A. In Saudi Arabia, data on antibiotic susceptibility of A. baumannii developed extensive resistance to many antibiotics, including broad-spectrum β-lactams and carbapenems, so rapid identification of the bacteria is imperative in making decisions on appropriate early treatment. They are difficult to destain, which can lead to initial misidentification as Gram-positive or Gram-variable. Acinetobacter baumannii are Gram-negative, strictly aerobic, catalase-positive, oxidase-negative bacteria which, in log phase, have the appearance of short, Gram-negative rods, but in stationary phase the organism has a coccoid appearance. Misinterpretation of initial Gram-negative staining from clinical sample cultures can result in misidentification of the causative bacteria and delays appropriate antibiotic treatment. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |