Fecal carriage of extended-spectrum ß-lactamase- and carbapenemase-producing Enterobacteriaceae in Egyptian patients with community-onset gastrointestinal complaints: a hospital -based cross-sectional study.

OBJECTIVES: The aim of this study was to determine the prevalence of extended-spectrum ß-lactamase (ESBL) and carbapenemase production among Enterobacteriaceae isolated from ambulatory patients with gastrointestinal complaints admitted to El-Ahrar General Hospital, Zagazig, Egypt in the period between January 2013 and May 2013. METHODS: One hundred and thirteen Enterobacteriaceae isolates were recovered from 100 consecutive Egyptian patients with community-onset gastrointestinal complaints. The fecal samples were plated directly on selective EbSA-ESBL Screening Agar and on MacConkey agar. Isolate identification was performed with matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Screening for ESBLs and carbapenemases production was done by both the automated VITEK®2 system with AST N198 and by disk diffusion method. Real-time PCR and sequencing were used to characterize the resistance genes. Phylogroups of the E. coli isolates were determined by a triplex PCR-based method. RESULTS: Of 100 patients screened for fecal colonization with extended-spectrum ß-lactamase -producing Enterobacteriaceae (ESBL-E) and carbapenemase- producing Enterobacteriaceae (CPE), 68 were colonized with ESBL-E whereas five patients were positive for CPE. One hundred and thirteen Enterobacterceae isolates were recovered from 100 fecal samples, they belonged to E. coli (n = 72), Klebsiella pneumoniae (n = 23), Enterobacter cloacae(n = 3), Salmonella spp. (n = 1) and other Enterobacterceae isolates (n = 14). The blaCTX-M gene was detected in 89.04% (65/73) of the ESBL-producing Enterobacteriaceae, whereas blaSHV and blaTEM were detected in 30.14% (22/73) and 19.18% (14/73) respectively. Three out of 5 carbapenem-resistant isolates harbored New Delhi metallo-beta-lactamase (NDM) and 2 produced Verona integron-encoded metallo- beta -lactamase (VIM). Twenty-two (47.83%) of the ESBL positive isolates were multidrug resistant (MDR). Phylogenetic analysis showed that, of the 51 ESBL-EC isolates, 17 belonged to group B2, 13 to group D, 11 to group A and 10 to group B1. CONCLUSIONS: Nearly two-thirds of the Enterobacteriaceae isolates recovered from feces of ambulatory patients with community-onset gastrointestinal complaints admitted to El-Ahrar General Hospital, Zagazig, Egypt were ESBL producers and one in every 20 patients included in our study was colonized by carbapenemase-producing Enterobacteriaceae. These high colonization rates are worrying, therefore prudent antimicrobial use should be adopted in Egyptian community settings.

Outline of a bacterial filter-based assay to detect beta-lactamases.

We describe a new phenotypic test to detect beta-lactamases. This assay is based on diffusion of beta-lactam/beta-lactamase through a bacterial filter. Beta-lactam hydrolysis on (the other side of) the filter leads to a change in antibiotic susceptibility, which can be measured by disc diffusion tests. We illustrate its ease of use to detect beta-lactamases of different classes.

Extended-Spectrum ß-Lactamases and/or Carbapenemases-Producing Enterobacteriaceae Isolated from Retail Chicken Meat in Zagazig, Egypt.

OBJECTIVES: The aim of the present study was to determine the prevalence and to characterize extended-spectrum ß-lactamases- and/or carbapenemases-producing Enterobacteriaceae among Enterobacteriaceae isolated from retail chicken meat in Zagazig, Egypt. METHODS: One hundred and six Enterobacteriaceae isolates were collected from retail chicken meat samples purchased in Zagazig, Egypt in 2013. Species identification was done by MALDI-TOF MS. Screening for ESBL-E was performed by inoculation of isolates recovered from meat samples onto the EbSA (Cepheid Benelux, Apeldoorn, the Netherlands) selective screening agar. ESBL production was confirmed by combination disc diffusion test with clavulanic acid (Rosco, Taastrup, Denmark). Carbapenemases production was confirmed with double disk synergy tests. Resistance genes were characterized by PCR with specific primers for TEM, SHV, and CTX-M and carbapenemases (KPC, NDM, OXA-48, IMP and VIM). PCR products of CTX-M genes were purified and sequenced. Phylogenetic grouping of E. coli was performed by a PCR-based method. RESULTS: Of these 106 isolates 69 (65.09%) were ESBL producers. Twelve (11.32%) of these isolates were also phenotypically class B carbapenemases producer. TEM genes were detected in 61 (57.55%) isolates. 49 (46.23%) isolates harbored CTX-M genes, and 25 (23.58%) carried genes of the SHV family. All CPE belonged to the NDM group. The predominant CTX-M sequence type was CTX-M-15 (89.80%). The majority (80%) of the ESBL-EC belonged to low virulence phylogroups A and B1. CONCLUSIONS: This is the first study from Egypt reporting high rates of ESBLs and carbapenemases (65.09% and 11.32%, respectively) in Enterobacteriaceae isolated from retail chicken meat. These results raise serious concerns about public health and food safety as retail meat could serve as a reservoir for these resistant bacteria which could be transferred to humans through the food chain.

Extended-Spectrum ß-Lactamase- and Carbapenemase-Producing Enterobacteriaceae Isolated from Egyptian Patients with Suspected Blood Stream Infection.

OBJECTIVES: The aim of the study was to investigate the prevalence of extended-spectrum ß-lactamase and carbapenemase production among Enterobacteriaceae isolated from Egyptian patients with suspected blood stream infection. METHODS: Ninety-four Enterobacteriaceae blood culture isolates from Egyptian patients with suspected blood stream infection were collected, one isolate per patient. Identification of bacterial isolates was performed with MALDI-TOF (MS-based Vitek MS system, bioMerieux). Screening for ESBLs and carbapenemases production was done with the Vitek 2 system (bioMérieux). ESBL production was confirmed using the combined disk diffusion method for cefotaxime, ceftazidime, and cefepime, all with and without clavulanic acid (Rosco). Real-time PCR and sequencing were used to characterize the resistance genes. The phylogenetic groups of E. coli were identified by a PCR-based method. RESULTS: Of the 94 Enterobacteriaceae isolates 46 (48.93%) showed an ESBL phenotype. One Enterobacter spp isolate was ESBL-producer and meropenem-resistant. The genetic analysis showed that CTX-M was present in 89.13% (41/46) of the ESBL-producing Enterobacteriaceae, whereas TEM and SHV were detected in 56.52% (26/46) and 21.74% (10/46) respectively (47.83%) of the ESBL-producing isolates were multidrug resistant (MDR). Eleven out of 30 ESBL-producing E-coli isolates were assigned to phylogroup B2, followed by groups B1 (8 isolates), A (6 isolates) and D (5 isolates). CONCLUSIONS: The high ESBL-E rates (48.93%) found in this study together with the identification of one carbapenem-resistant Enterobacter spp isolate is worrisome. Our results indicate that systems for monitoring and detection of ESBL-producing bacteria in Egyptian hospitals have to be established. Also strict hospital infection control policies with the restriction of the consumption of extended-spectrum cephalosporins are necessary.

The cost-effectiveness of ESBL detection: towards molecular detection methods?

Correct detection of extended-spectrum beta-lactamases (ESBLs) is crucial for infection control and antibiotic choice. We performed a study to determine the cost-effectiveness of phenotypical testing, which can be inaccurate, and genotypical tests, which are considered to be more reliable but also more expensive. All patients that had been in isolation in the Amphia hospital because of the detection of ESBL according to the ESBL Etest were included in the survey. All strains were retested using the double disk confirmation test (DDCT) and a genotypical method. This was a commercially available microarray (Check-Points). Discordant results were confirmed by PCR and sequencing. In total 174 patients were included. In 24 of 174 (14%) patients, ESBL carriage could not be confirmed with the microarray. This was verified with PCR and sequencing. The mean duration of isolation was 15 days, adding up to a total number of isolation days of 2571. False-positive results according to the microarray resulted in a total of 279 days of unnecessary isolation for the Etest and 151 days for the DDCT. Using Etest to detect the presence of ESBL results in a false-positive outcome in 14% of the cases. This results in unnecessary isolation of patients, which can be omitted by using a genotypic method.