Rapid bacterial identification by MALDI-TOF MS directly from blood cultures and rapid susceptibility testing: A simple approach to reduce the turnaround time of blood cultures

Abstract Antimicrobial treatment of patients with bloodstream infections (BSI) is time-sensitive. In an era of increasing antimicrobial resistance, rapid detection and identification of bacteria with antimicrobial susceptibility are critical for targeted therapy early in the disease course. This study describes the performance of a rapid method for identifying and testing antimicrobial susceptibility of Gram-negative bacteria performed directly from blood culture bottles in a routine microbiology laboratory. A total of 284, 120, and 24 samples were analyzed by rapid identification (Rid), rapid susceptibility testing (RAST), and rapid broth microdilution for polymyxin B (rMIC), respectively, and compared with standard methods. Our protocol was able to identify 93% of isolates at the species level using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). We obtained 100% agreement for RAST compared to the standard method and 96% agreement for rMIC. Our protocol has proven to be an excellent tool for rapid identification of Gram-negative bacilli causing BSIs. It can also be used in microbiology laboratory routine along with RAST and faster polymyxin microdilution, especially for carbapenemase-producing bacteria, allowing for rapid, simple, accurate, and cost-effective diagnosis.

Consensus of the Brazilian Society of Infectious Diseases and Brazilian Society of Clinical Oncology on the management and treatment of Kaposi's sarcoma

Kaposi's sarcoma is a multifocal vascular lesion of low-grade potential that is most often present in mucocutaneous sites and usually also affects lymph nodes and visceral organs. The condition may manifest through purplish lesions, flat or raised with an irregular shape, gastrointestinal bleeding due to lesions located in the digestive system, and dyspnea and hemoptysis associated with pulmonary lesions. In the early 1980s, the appearance of several cases of Kaposi's sarcoma in homosexual men was the first alarm about a newly identified epidemic, acquired immunodeficiency syndrome. In 1994, it was finally demonstrated that the presence of a herpes virus associated with Kaposi's sarcoma called HHV-8 or Kaposi's sarcoma herpes virus and its genetic sequence was rapidly deciphered. The prevalence of this virus is very high (about 50%) in some African populations, but stands between 2% and 8% for the entire world population. Kaposi's sarcoma only develops when the immune system is depressed, as in acquired immunodeficiency syndrome, which appears to be associated with a specific variant of the Kaposi's sarcoma herpes virus. There are no treatment guidelines for Kaposi's sarcoma established in Brazil, and thus the Brazilian Society of Clinical Oncology and the Brazilian Society of Infectious Diseases developed the treatment consensus presented here.

Autologous transplant: microbial contamination of hematopoietic stem cell products

Hematopoietic progenitor cells from peripheral blood (HPCPB) are commonly used for autologous and allogenic transplants in patients with most various onco-hematological diseases, and despite the utilization of sterile techniques during collection and processing of these products, bacterial contamination can occur. This study aimed to investigate the microbial contamination of HPCPB products. Microbial cultures of 837 HPCPB products between the year 2000 and 2009 were retrospectively analyzed to determine the incidence of culture positivity and identify the main organisms that cause contamination. The microbiological studies were performed with an automated system (BacT/Alert® bioMérieux Corporate). Thirty-six (4.3%) of 837 microbial cultures were contaminated. Coagulase-negative Staphylococcus was the most frequent bacteria isolated from HPCPB products (20 [56%] of the 36 positive microbial cultures). Considering the 36 contaminated samples, 22 HPCPB products were infused and 14 discarded. Pre-and post-infusion antibiotic therapy of the patients transfused with contaminated products was established based on the isolated microorganism and its antibiogram. Microbial contamination rate of HPCPB products was low. Clinically significant outcomes after infusion of contaminated HPCPB products were not observed.

Prevalence, susceptibility profile for fluconazole and risk factors for candidemia in a tertiary care hospital in southern Brazil

Bloodstream infections caused by yeast, Candida spp, are quite important clinically and epidemiologically due to a high mortality rate and an increasing number of non-albicans species with a more resistant (differentiated susceptibility) profile. We examined species prevalence and susceptibility profile for fluconazole and the risk for nosocomial infections by Candida spp at the Hospital de Clínicas de Porto Alegre, a general tertiary care hospital in southern Brazilian, through a retrospective study, beginning with positive cultures of hospitalized patients. The distribution by species in 131 documented episodes was as follows: Candida albicans (45 percent), C. parapsilosis (24.4 percent), C. tropicalis (15.3 percent), C. glabrata (6.9 percent), C. krusei (4.6 percent) and 3.8 percent other species (C. pelicullosa, C. guilliermondii, C. lusitaniae and C. kefyr). The vast majority of samples (121- 92.4 percent) were susceptible to fluconazole; the resistant or dose-dependent sensitive samples included only C. krusei and C. glabrata. Blood diseases (leukemia, lymphoma), or neoplasias (solid tumors), were found in 35.0 percent of the candidemia episodes. We noted the previous use of antibiotics in 128 (97.7 percent) patients, with 79.7 percent using three or more antibiotics before the candidemia episode. Other risk factors included a central venous catheter in 94 (71.8 percent) and abdominal surgery in 32 (24.4 percent) patients. The overall mortality rate was 51.9 percent, which varied according to the underlying disease. We found that C. albicans was the most prevalent species, although the non-albicans species predominated. However, in vitro resistance to fluconazole was detected only among the species (C. glabrata and C. krusei) that tend to be resistant to the azolic compounds. Previous use of antibiotic and the use of a central venous catheter were the main risk factors among patients with candidemia.