Dear Editor,
We isolated Burkholderia cepacia from blood and sputum samples of cancer patients having febrile neutropenia. B. cepacia was identified using Gram-negative GN REF 21341 identification card in automated VITEK®2 Compact (C) system (Biomeriux, North Carolina/USA). Antibiotic susceptibility results were expressed as susceptible, intermediate or resistant according to the criteria of the Clinical Laboratory Standards Institute M100-S23 (2013).[1]
B. cepacia was isolated from blood samples collected aseptically from five patients suffering from non-Hodgkin's lymphoma, renal cell carcinoma, carcinoma cecum with liver metastasis, acute myeloid leukemia and periampullary carcinoma; and from good quality sputum sample of a patient suffering from carcinoma lung. Detailed clinical history along with informed consent regarding possible publication was taken from all the patients. All the isolates of B. cepacia were resistant to aminoglycoside antibiotics and ciprofloxacin; and were sensitive to co-trimoxazole, meropenem, piperacillin, piperacillin-tazobactam and cefepime. Five were susceptible to ceftazidime also.
The 2010 Sanford Guide recommends co-trimoxazole as the treatment of choice for this infection. In addition, it lists 5 antibiotics to which more than 60% of clinical isolates of B. cepacia are susceptible or that are clinically effective: Meropenem, ceftazidime, ceftibuten, chloramphenicol and trimethoprim.[2] Since myelosuppression is a known side-effect of co-trimoxazole, it could not be used in our patients already having neutropenia. Adverse reactions are also more common with meropenem compared to piperacillin-tazobactam. Hence our patients were treated with intravenous piperacillin-tazobactam. The patients recovered clinically and repeat blood and sputum cultures were negative.
Over the past few decades, Burkholderia spp. has become an emerging opportunistic pathogen, most commonly reported in patients suffering from cystic fibrosis.[3] However, it is not commonly encountered in immune-suppressed oncology patients despite their compromised state and propensity for acquiring infections caused by Gram-negative pathogens.[4] There are few reports available regarding infections due to Burkholderia in the general oncology population. In general, Burkholderia manifests innate resistance to aminoglycoside antibiotics and widespread resistance to many beta-lactam agents, including extended-spectrum penicillins such as piperacillin and the 4th generation cephalosporin cefepime.[2] However, in our study we found that all the isolates were uniformly susceptible to piperacillin, piperacillin-tazobactam and cefepime. So the antibiogram of Burkholderia spp. isolated from our cancer patients, by retaining susceptibility to these three antibiotics, seemed to be slightly different from those isolated from other cases. Similar findings were reported in a study by Heo et al.[5] They described an outbreak of Burkholderia stabilis in eight patients with underlying malignancies of acute lymphoblastic leukemia or acute myeloid leukemia at a university teaching hospital in Korea. Interestingly, the strains of B. stabilis isolated from this study were susceptible to a wider range of antibiotics, including piperacillin/tazobactam and cefepime, an uncommon occurrence for patients infected with Burkholderia spp.
Our findings indicate that Burkholderia spp. isolated from cancer patients may manifest an antibiogram different from that usually observed, by retaining susceptibility to more number of antibiotics especially to piperacillin-tazobactam and cefepime.
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