Antimicrobial susceptibility of clinical Enterobacteriaceae isolates at the emergency department in a regional hospital: A threat of extended spectrum beta-lactamase-producers among nursing home residents.

The prevalence of extended spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae in nursing home residents has rarely been reported in Taiwan. A retrospective study was performed at medical wards of a district hospital at southern Taiwan between July 2009 and June 2011. Patients were included if they were older than 18 years, admitted via the emergency department, and their blood, sputum, or urine culture revealed the growth of Escherichia coli, Klebsiella pneumoniae, or Proteus mirabilis. From each patient only the first isolate from the infection site was included. Antimicrobial susceptibility was determined using the disc diffusion method. Overall, 827 patients were included, with 354 (42.8%) coming from the community and 473 (57.2%) referred from a nursing home. Of the isolates acquired in nursing home, 45.5% (215/473) harbored ESBL. By contrast, 20.6% (73) of 354 isolates acquired in the community exhibited the ESBL production phenotype (p < 0.001). Of the isolates obtained from blood, urine, or sputum, 28.2% (37/131), 36.0% (208/578), or 36.4% (43/118) harbored ESBL, respectively, whereas 41% (211) of 515 E. coli isolates, 34.3% (72) of 210 K. pneumoniae, and 4.9% (5) of 102 P. mirabilis had ESBL. In general, the isolates from a nursing home or those with ESBL had lower antimicrobial susceptibility rates than those from the community or those without ESBL production. Only amikacin, piperacillin/tazobactam, ertapenem, and imipenem/meropenem were active against >90% Enterobacteriaceae isolates, irrespective of ESBL production. ESBL production was common among clinical Enterobacteriaceae isolates, especially E. coli or those isolated from nursing home residents.

Liu HC ，Hung YP ，Lin HJ ，Liu HC ，Lee JC ，Wu YH ，Li CW ，Li MC ，Ko WC ... -  《-》

In vitro activity of flomoxef and comparators against Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis producing extended-spectrum β-lactamases in China.

The objective of this study was to better understand the in vitro activity of flomoxef against clinical extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae. A total of 401 ESBL-producing isolates, including 196 Escherichia coli, 124 Klebsiella pneumoniae and 81 Proteus mirabilis, were collected consecutively from 21 hospitals in China in 2013. Minimum inhibitory concentrations (MICs) were determined by broth microdilution methods. Phenotypic identification of ESBL production was detected as recommended by the Clinical and Laboratory Standards Institute (CLSI). ESBL genes were detected by PCR and sequencing. Flomoxef, doripenem, meropenem, ertapenem, cefmetazole and piperacillin/tazobactam exhibited good activity against ESBL-producing isolates, with susceptibility rates >90%. Tigecycline showed good activity against E. coli and K. pneumoniae (100% and 97.6%, respectively). Cefotaxime and cefepime showed very low activities against ESBL-producing isolates, with susceptibility rates of 0-0.8% and 1.0-13.6%, respectively. blaCTX-M were the major ESBL genes, with occurrence in 99.5% of E. coli, 91.1% of K. pneumoniae and 97.5% of P. mirabilis. blaCTX-M-14 was the predominant ESBL gene, detected in 46.9% (188/401) of the isolates, followed by blaCTX-M-15 (21.4%), blaCTX-M-55 (17.2%), blaCTX-M-65 (12.7%) and blaCTX-M-3 (6.7%). Flomoxef exhibited excellent activity against the different CTX-M-type ESBL-producing isolates, with MIC50 and MIC90 values of 0.064-0.125μg/mL and 0.25-0.5μg/mL, respectively. Against the isolates solely producing CTX-M-14, -15, -55, -3 or -65, flomoxef showed susceptibility rates of 98.6%, 98.0%, 98.1%, 100.0% and 97.4%, respectively. In conclusion, flomoxef showed good activity against ESBL-producing Enterobacteriaceae and may be a choice to treat infections caused by these isolates in China.

Yang Q ，Zhang H ，Cheng J ，Xu Z ，Xu Y ，Cao B ，Kong H ，Ni Y ，Yu Y ，Sun Z ，Hu B ，Huang W ，Wang Y ，Wu A ，Feng X ，Liao K ，Shen D ，Hu Z ，Chu Y ，Lu J ，Su J ，Gui B ，Duan Q ，Zhang S ，Shao H ... -  《-》

[Investigation of the susceptibilities of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella spp. strains to ertapenem and other carbapenems].

Infections caused by extended-spectrum beta-lactamase (ESBL) producing Escherichia coli and Klebsiella spp. constitute severe problems. Carbapenems are commonly used to treat these infections. However, infections caused by carbapenem-resistant gram-negative bacteria show an increasing trend recently. The aim of this study was to investigate the susceptibilities of ESBL-producing E.coli and Klebsiella spp. to ertapenem and other carbapenems. A total of 239 E.coli, 28 K.pneumoniae and 11 K.oxytoca strains isolated from clinical specimens (208 urine, 16 blood, 26 wound, 17 sterile body fluids, four tracheal aspirates and seven others) of hospitalized patients and outpatients between January 2007-February 2008, were included to the study. The isolates were identified by conventional methods, and antibiotic susceptibility tests were performed by Kirby Bauer disc diffusion method according to Clinical and Laboratory Standards Institute (CLSI) standards. ESBL production was tested by double disk diffusion method. When ESBL production was indeterminate, cefotaxime-clavulanic acid E test (BioMerieux, France) was used. According to the CLSI standards modified Hodge test was performed for carbapenem resistant isolates and minimal inhibitory concentration (MIC) values were detected for ertapenem (Etest®, BioMerieux, France), imipenem and meropenem (M.I.C. Evaluator Strips, Oxoid, UK). All of the isolates were found susceptible to amikacin (278/278; 100%), whereas the susceptibility rates for imipenem/meropenem and ertapenem were 99.3% (276/278) and 98.6% (274/278), respectively. When evaluated individually, ertapenem susceptibilities of E.coli, K.pneumoniae and K.oxytoca strains were 99.2%, 96.4% and 90.9%, respectively, while these rates were 100%, 96.4% and 90.9%, respectively, for imipenem/meropenem. Carbapenem resistance was detected in two E.coli, one K.oxytoca and one K.pneumoniae isolates. While two Klebsiella spp. İsolates were resistant to all of the tested carbapenems (MIC > 32 µg/ml), two E.coli isolates were resistant to ertapenem (MIC > 32 µg/ml) but susceptible to imipenem (MIC= 0.25 µg/ml) and meropenem (MIC= 0.5 µg/ml). Carbapenemase production was demonstrated by modified Hodge test in all of the carbapenem-resistant isolates. In conclusion, ESBL-producing gram-negative isolates should be routinely tested with a screening method for carbapenemase activity and confirmation tests should be performed in suspected cases.

Kuzucu C ，Yetkin F ，Görgeç S ，Ersoy Y ... -  《MIKROBIYOLOJI BULTENI》

EMERGENCY ROOM: AN UNRECOGNIZED SOURCE OF EXTENDED-SPECTRUM β-LACTAMASE PRODUCING ESCHERICHIA COLI AND KLEBSIELLA PNEUMONIAE.

Pornsinchai P ，Chongtrakool P ，Diraphat P ，Siripanichgon K ，Malathum K ... -  《SOUTHEAST ASIAN JOURNAL OF TROPICAL MEDICINE AND PUBLIC HEALTH》

Prevalence and antimicrobial susceptibility of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae in a general hospital.

Kader AA ，Kumar A 《-》