Assessment of prevalence and changing epidemiology of extended-spectrum β-lactamase–producing Enterobacteriaceae fecal carriers using a chromogenic medium

Current Trends in Culture-Based and Molecular Detection of Extended-Spectrum-β-Lactamase-Harboring and Carbapenem-Resistant Enterobacteriaceae

“…and Citrobacter spp.) and penicillinases (K. oxytoca), and, to a minor extent, also narrow-spectrum TEM and SHV and OXA penicillinases (9,10,18,22,23). Importantly, frequency of false-positive results after 24 h of incubation was 3-fold higher on BLSE agar compared to that on chromID ESBL agar (22).…”

“…Five studies evaluated chromID ESBL using mainly fecal, respiratory, and urine samples and observed high sensitivities (88% to 100%) and specificities (90% to 96%) for this medium (Table 2). NPVs were uniformly high (Ͼ98%), while positive predictive values (PPVs) varied between studies (39% to 74%), depending on the prevalence of ESBL producers at study sites that ranged from 4% to 11% (9,10,18,22,23). Higher sensitivities and PPVs were reported for CHROMagar ESBL (100% and 52%) than chromID ESBL (88% and 46%), as two ESBL-harboring E. coli strains appeared colorless on the latter medium (23).…”

“…One study showed an increase in sensitivity (88% to 94%) and a decrease in specificity (94% to 91%) of chromID ESBL with prolonged incubation (48 h), while another did not observe an increase in sensitivity at 48 h, although the recovery of ESBL producers was complicated due to growth of associated flora on this medium (9,22). On the other hand, another study reported no difference in growth with prolonged incubation of samples on chromID ESBL (18).…”

Rectal Carriage of Extended-Spectrum-Beta-Lactamase-Producing Enterobacteriaceae in Hospitalized Patients: Selective Preenrichment Increases Yield of Screening

“…Unfortunately, reliable standardized methods for direct molecular detection of ESBL-E in clinical specimens are currently not available for routine use in medical microbiology. Therefore, the targeted ESBL-E screening of clinical specimens relies on the use of selective screening agars for ESBL, several of which, with comparable high sensitivities, have been described (7)(8)(9)(10)(11)(12)(13). It has been shown that preenrichment using a broth improves the performance of selective screening agars for the detection of methicillin-resistant Staphylococcus aureus in clinical specimens (14)(15)(16)(17).…”

Comparison of Five Media for Detection of Extended-Spectrum Beta-Lactamase by Use of the Wasp Instrument for Automated Specimen Processing

“…Moreover, if molecular tests for ESBL detection are expected to give a faster result than culture, the cost of these tests for large series is currently still too high relative to that of traditional culture. In this situation, agar manufacturers have improved their media for detection of ESBLs after only 24 h (10)(11)(12)(13)(14)(15)(16). Taking advantage of the Wasp instrument, an automated device for microbiological specimen processing, planting, and streaking (Copan, Brescia, Italy), we decided to compare the efficiencies of five selective media designed for ESBL detection.…”