ABSTRACT
To describe the misidentification of Brucella melitensis as Bergeyella zoohelcum by MicroScan WalkAway, a commonly used bacterial identification system. A 35-year-old man was admitted to the Intensive Care Unit with sepsis syndrome. Three sets of aerobic blood culture samples were positive after 48 h of incubation. The isolated organism was identified as B. zoohelcum using the MicroScan WalkAway [Siemens Healthcare Diagnostics Inc., West Sacramento, Calif., USA]. However, due to the rareness of the pathogen, the isolate was reidentified as B. melitensis with Vitek 2 system and later 16S ribosomal sequence analysis confirmed the isolate as B. melitensis having 100% match. This case showed that Brucella can be misidentified using MicroScan WalkAway. Countries where brucellosis is endemic need to be careful while using such automated identification systems in order not to miss the diagnosis of Brucella
ABSTRACT
To investigate the prevalence and antibiotic susceptibility pattern of extended-spectrum beta-lactamases [ESBL]-producing Enterobacteriaecae among patients in the United Arab Emirates. A total of 130 Enterobacteriaceae comprising of Escherichia coli [n = 83], Klebsiella pneumoniae [n = 45] and Klebsiella oxytoca [n = 2] was studied. Of these 130 isolates, 64 were from urine. ESBL screening was by disc diffusion and confirmatory tests for ESBL phenotype were conducted using BD Phoenix[TM] ESBL System and cephalosporin/clavulanate combination discs. Susceptibility to a panel of antibiotics was evaluated. Of the 130 isolates, 53 [41%] were identified as having ESBL phenotype; of these, 32 [60%] were E. coli, 20 [36%] K. pneumoniae and 2 [4%] K. oxytoca. ESBL phenotype was seen in 100% of endotracheal tubes isolates, 20 [31%] from urine, 7 [58%] from blood and 4 [80%] from catheter tips. Amikacin susceptibility was 100%. Over 90% of ESBL isolates showed resistance to aztreonam and cephalosporins. All Klebsiella isolates were carbapenem sensitive. One ESBL isolate showed intermediate resistance to imipenem and meropenem [both MIC 8 micro g/ml], cefotetan [MIC 32 micro g/ml] and piperacillin/ tazobactam [MIC 32 micro g/ml]. MIC for the carbapenems was lower in non-ESBL isolates [0.034 micro g/ml] than ESBL isolates [0.071 micro g/ml]. Resistance to gentamicin, ciprofloxacin and piperacillin/tazobactam was higher in ESBL than non-ESBL isolates [p < 0.05]. A high prevalence of ESBL-producing bacteria exists among in-patients in the United Arab Emirates. Amikacin and carbapenems remain the most effective drugs, but the presence of carbapenem-resistant ESBL-producing E. coli and occurrence of multidrug resistance are of concern. Continued surveillance and judicious antibiotic usage are recommended