الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
BCC is a group of 17 closely-related species that are ubiquitous in nature and found particularly in soil and water. For a long time, BCC was believed to be only a plant pathogen, but later on, it has emerged as an important opportunistic pathogen that causes serious infections in clinical settings, particularly among patients with prior broad-spectrum antibiotic therapy. B. cepacia is an aerobic, motile, glucose non fermenting, multidrug resistant gram negative bacillus that proliferates under conditions of minimal nutrition and can survive in the presence of certain disinfectants. The most common species of BCC include: B. cepacia, B. multivorans and B.cenocepacia.
BCC has emerged as an important HCA pathogen causing morbidity and mortality in hospitalized patients, largely because of its high intrinsic antibiotic resistance. It is one of the most antimicrobial resistant organisms encountered. BCC is intrinsically resistant to antimicrobial agents such as aminoglycosides, first and second generation cephalosporins, antipseudomonal penicillins and polymyxins. In addition, it survives and multiplies in aqueous hospital environments, where it may persist for long periods; thus giving an extreme value to its proper identification.
Infections caused by BCC include bacteremia, urinary tract infections, septic arthritis, peritonitis and respiratory tract infections particularly in patients with cystic CF. However; the pathogenicity of BCC is not always limited to CF or immunocompromised patients. Among non-CF hospitalized patients, hemodialysis, permanence in ICUs, use of central venous catheters, indwelling urinary catheters, and endotracheal tubes are recognized as risk factors contributing for BCC acquisition. Outbreaks of BCC septicemia have been documented worldwide in ICUs, oncology units and renal failure patients.
The identification of this organism is not straight forward and poor laboratory proficiency in identification of this organism still prevails. The policy that should be strictly adopted in routine clinical laboratories for the identification of putative BCC isolates should generally include the use of an efficient selective medium, conventional biochemical analysis and a special commercial system for the confirmation of its identity.
This cross sectional study was carried out during a 4-month period from February to May2016. It included a total of 150 different clinical samples collected from 118 patients who were admitted to the ICUs at Mabaret El Asafra and Petroleum hospitals. All samples were collected and processed according to the standard microbiological methods. For the isolation of BCC, samples were cultured on conventional media including Blood and MacConkey’s agar plates in addition to selective BCSA plates. Isolated colonies were identified using conventional biochemical tests together with Rap ID NF Plus system and Vitek 2 compact system. Identified BCC isolates were tested for their antimicrobial susceptibility pattern using single disc diffusion method. Inhibition zones were measured, recorded and interpreted according to the CLSI guidelines.
The results of this study showed that:
1. Causative agents were isolated and identified in 111 samples (74%), while in the remaining 39 samples (26%) no agents were isolated.
2. Gram negative bacilli were isolated from 81/150 (74%) of examined samples, and gram positive cocci were isolated from 24 (21.6%) samples, while only 6 (5.4%) examined samples yield fungi.
3. It is apparent that when the duration of stay in ICU increased the infection rate increased ranging from 28.6% in the first week till 88.9% in the third week in Mabaret El Asafra hospital and from 14.3% in the first week till 90.9% in the third week in Petroleum hospital.
4. Of the 111 isolates, BCC was isolated and identified in 8 isolates (7.2%); six from Mabaret El Asafra hospital and two from Petroleum hospital.
5. The highest rate of BCC occurred in male (75%).
6. The highest rate of BCC isolates was among those aged 60-80 years old (50.0%).
7. The highest rate of isolation of BCC occurred in the third week of stay in the ICU (62.5%).
8. The highest rate of isolation of BCC occurred in patients with pulmonary diseases (37.5%).
9. The highest rate of isolation of BCC occurred from sputum samples (50.0%).
10. BCC isolates were highly susceptible to ceftazidime, meropenem, and piperacillin- tazobactam.
from the results of this study, it could be concluded that:
• BCC is not uncommon among oxidase positive NFGNB isolated from clinical specimens received in routine microbiology laboratory. It has been ambiguously reported as oxidase positive NFGNB or Pseudomonas spp. but was never reported as Burkholderia spp.
• The introduction of the BCSA medium for screening of BCC strains supported the growth of Burkholderia, C. albicans, K. pneumoniae, and E. coli but totally inhibited Pseudomonas spp.
• The simple testing for oxidase, motility, lysine and ornithine decarboxylases allowed the differentiation between the isolates on BCSA and provided the preliminary identification of BCC.
• RapID NF Plus system proved to be accurate in confirming the identity of BCC. It was also able to characterize these isolates.
• All strains of BCC tested for antibiotic susceptibility were found to be MDR. All strains were resistant to ciprofloxacin and ticarcillin-clavulante, but most susceptible to ceftazidime and meropenem.