Prevalence and characterization of extended-spectrum β-lactamase–producing Enterobacteriaceae isolated in Korean hospitals

Choe

Antimicrob Agents Chemother

et al. 2013

i This study aimed to (i) investigate the antimicrobial susceptibilities of bacteria that cause urinary tract infections (UTIs) in outpatient and inpatient settings and (ii) evaluate the risk factors for emerging antimicrobial drug resistance in UTIs in South Korea. In total, 3,023 samples without duplication were collected from females between 25 and 65 years of age who had been diagnosed with a urinary tract infection. Multicenter patient data were collected using a Web-based electronic system and then evaluated. The isolation rates of Escherichia coli, Klebsiella pneumoniae, and Enterococcus faecium in the outpatient setting were 78.1, 4.7, and 1.3%, respectively; in the inpatient setting, the isolation rates of these microorganisms were 37.8, 9.9, and 14.8%, respectively. The susceptibilities of E. coli to amikacin, amoxicillin-clavulanic acid, cefotaxime, cefoxitin, ciprofloxacin, piperacillin-tazobactam, and imipenem in the outpatient setting were 99.4, 79.8, 89.4, 92.8, 69.8, 96.9, and 100.0%, respectively; in the inpatient setting, the susceptibilities to these antibiotics were 97.8, 73.9, 73.7, 82.1, 53.6, 93.2, and 100.0%, respectively. The most unique and common risk factor for emerging antimicrobial-resistant E. coli, K. pneumoniae, and E. faecium was previous exposure to antimicrobials. On the basis of these data, the use of fluoroquinolones should be reserved until culture data are available for the treatment of UTIs in South Korea. The present study will serve as a useful reference for Far Eastern Asia.

Section: Discussioncontrasting

confidence: 38%

Antimicrobial Susceptibility Pattern and Epidemiology of Female Urinary Tract Infections in South Korea, 2010-2011

Choe

Antimicrob Agents Chemother

et al. 2013

“…Consistent with other reports from around the world, SHV-12 was the major ESBL identified in our Enterobacter bloodstream isolates (1,4,8,9). This is in spite of data from Lewis and colleagues (10) at the same institution indicating that a few Enterobacter isolates produced CTX-M ESBLs.…”

supporting

confidence: 32%

Detection of SHV-Type Extended-Spectrum Beta-Lactamase in Enterobacter Isolates

Towne

Lewis

Herrera³

et al. 2010

J Clin Microbiol

One hundred four Enterobacter isolates were tested by standard CLSI disk diffusion methods for detecting extended-spectrum beta-lactamases (ESBLs) and with cefepime-clavulanate disk combinations. SHV-12 was produced by 8.7% of isolates. The cefepime-clavulanate combination provided 88% sensitivity and 91% specificity for the detection of SHV-12 ESBL.Detection of extended-spectrum beta-lactamase (ESBL) production in Enterobacter spp. has not been undertaken by most clinical laboratories due to a lack of recommendations from the Clinical and Laboratory Standards Institute (CLSI) and potential interference in test interpretation from highlevel production of an AmpC beta-lactamase (5). This inability to readily identify ESBLs in pathogens that potentially coproduce AmpC beta-lactamase and an ESBL presents a concern for providers considering cefepime therapy for these patients, since there is an inoculum effect with ESBLs that affects all cephalosporins (2,6,7,13,16). Detection of an ESBL could lead to selection of a carbapenem for therapy rather than a cephalosporin like cefepime due to a potentially poorer clinical response (4,11,14,17), whereas Enterobacter isolates that produce only AmpC have been treated reliably with cefepime (12).Enterobacter isolates recovered from blood cultures at the University Health System in San Antonio, TX, between 1 October 2004 and 31 December 2007 were examined in this study. These represented the first isolates from each patient and were nonrepetitive, with the exception of one patient, from whom two different Enterobacter spp. were identified. Initial identification and susceptibility testing were performed using a Vitek 2 instrument (GN13 cards; bioMerieux, Durham, NC) and/or standard CLSI disk diffusion methodologies (3). All isolates underwent ESBL phenotypic confirmatory disk testing utilizing the cefotaxime-and ceftazidime-clavulanate combinations as described by CLSI for Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, and Proteus mirabilis (3). In addition, cefepime disks (30 g) were tested and zone diameters were recorded in a comparison with cefepime disks to which 10 g of clavulanate was added in an attempt to improve the ability to detect ESBL production in organisms producing native AmpC beta-lactamase. E. coli ATCC 25922, E. coli ATCC 35218, and K. pneumoniae ATCC 700603 were included with each day's tests for quality control purposes. Zone diameters were recorded for the antimicrobial agent combinations with each isolate. Any isolate with a zone diameter that increased by at least 3 mm (the minimum zone difference that we felt could be reliably measured) with the addition of clavulanate for any of the three cephalosporins or for which no zone of inhibition was seen around any of the three cephalosporin disks was considered a possible ESBL producer and was subjected to further examination.Using previously described methods, those isolates meeting the screening criteria and a random sampling of 15 isolates not meeting those criteria (control group) were fur...

Experimental and Therapeutic Medicine

“…Additionally the highly prevalent class I integron contains antibiotic resistance genes, mainly for aminoglycoside antibiotics and trimethoprim (19,20). Similar results have been reported in isolates from Korean hospitals; however, SHV-12 ESBL-positive and -negative isolates did not show significant differences in antibiotic resistance to the β-lactam antibiotics (21). Other mechanisms may, therefore, also contribute to β-lactam antibiotic resistance.…”

Section: Resultssupporting

confidence: 75%

Association of antibiotic resistance with SHV-12 extended-spectrum β-lactamase in Enterobacter cloacae

Liu

Lin

et al. 2015

Abstract.The association between antibiotic resistance and SHV-12 extended-spectrum β-lactamase (ESBL) in Enterobacter cloacae remains unknown. The aim of the present study was to investigate the prevalence of both chromosome-and plasmid-borne SHV-12 ESBL genes in Enterobacter cloacae. Transmission of the SHV-12 ESBL gene was explored, and the risk factors for antibiotic resistance in E. cloacae were analyzed. Polymerase chain reaction (PCR) results showed that 58 out of the 100 isolates carried the SHV-12 ESBL gene: 34.48% of them occurred in the chromosome, 48.28% were plasmid-borne and 17.24% appeared in both. Enterobacterial repetitive intergenic consensus-PCR tests detected 82 chromosomal genotypes. Conjugation assays showed that 70.00% of plasmid-borne SHV-12 ESBL genes were successfully transconjugated into E. coli C600 and that the antibiotic resistance phenotype of E. cloacae was partially (84%) or completely (10%) transferred. A significantly higher SHV-12 ESBL detection rate was found in patients with underlying conditions and/or complications compared with those without (P<0.05). The detection of SHV-12 ESBL-producing E. cloacae from vertical transmission varied significantly across clinical departments and age groups (P<0.05), with the highest rates in the intensive care unit and the group of patients aged ≥60 years. The present results indicate that the location and transmission efficiency of SHV-12 ESBL are closely correlated with the antibiotic resistance of E. cloacae.