scholarly journals Performance of the Phoenix bacterial identification system compared with disc diffusion methods for identifying extended-spectrum β-lactamase, AmpC and KPC producers

2009 ◽  
Vol 58 (6) ◽  
pp. 774-778 ◽  
Author(s):  
Mark A. Fisher ◽  
Paul D. Stamper ◽  
Kristine M. Hujer ◽  
Zachary Love ◽  
Ann Croft ◽  
...  

Phenotypic identification of AmpC, KPC and extended-spectrum β-lactamases (ESBLs) among members of the Enterobacteriaceae remains challenging. This study compared the Phoenix Automated Microbiology System (BD Diagnostics) with the Clinical and Laboratory Standards Institute confirmatory method to identify ESBL production among 200 Escherichia coli and Klebsiella pneumoniae clinical isolates. The Phoenix system misclassified nearly half of the isolates as ESBL-positive, requiring manual testing for confirmation. Inclusion of aztreonam±clavulanic acid (CA) and cefpodoxime±CA in the testing algorithm increased the ESBL detection rate by 6 %. Boronic acid-based screening identified 24 isolates as AmpC+, but in a subset of genotypically characterized isolates, appeared to have a high false-positivity rate. PCR screening revealed eight KPC+ isolates, all of which tested as ESBL+ or ESBL+ AmpC+ by phenotypic methods, but half were reported as carbapenem-susceptible by the Phoenix system. Overall, these results indicate that laboratories should use the Phoenix ESBL results only as an initial screen followed by confirmation with an alternative method.

2007 ◽  
Vol 56 (1) ◽  
pp. 52-55 ◽  
Author(s):  
Christopher I. Birkett ◽  
Hugo A. Ludlam ◽  
Neil Woodford ◽  
Derek F. J. Brown ◽  
Nicholas M. Brown ◽  
...  

The prevalence of CTX-M-producing members of the Enterobacteriaceae is increasing worldwide. A novel, multiplex, real-time TaqMan PCR assay to detect and type bla CTX-M genes is described which is an improvement on previously described techniques with respect to reduced assay time, elimination of the need for protracted post-PCR processing and the convenience of a single reaction vessel. Based on β-lactam antibiogram and MIC data, 478 of 1279 Enterobacteriaceae isolates from clinical blood and urine culture specimens were selected and tested for extended-spectrum β-lactamase (ESBL) production using phenotypic methods. The new TaqMan assay detected and typed bla CTX-M genes in 21 of 28 ESBL-producing isolates.


2016 ◽  
pp. 29-33
Author(s):  
Nazratan Naeem ◽  
Munawar Sultana ◽  
M Anwar Hossain

In this study, a modified boronic acid (MBA) disc potentiation assay has been used to detect extended spectrum â-lactamase (ESBL) producing isolates from clinical liquid waste (CLW) in Bangladesh. The method is modified from the existing boronic acid (BA) disc potentiation assay in that, in our protocol only one type of antibiotic disc is required in comparison to the requirement of different types of antibiotic discs for the BA test. Clavulanic acid (CA) and Boronic acid (BA) were used to phenotypically identify ESBL and AmpC producers, respectively. A total of 181 multidrug-resistant (MDR) isolates were screened for ESBL production by both the conventional double disc diffusion synergy test (DDST) and the MBA disc potentiation test. Among these two methods, 38% of the isolates showed positive ESBL phenotype in MBA test in comparison to the 24% of the isolates in DDST, hence showed higher efficiency. The MBA method described here is efficient, easy to perform, and cost effective to detect ESBL producing bacteria.Bangladesh J Microbiol, Volume 31, Number 1-2,June-Dec 2014, pp 29-33


2000 ◽  
Vol 38 (1) ◽  
pp. 246-251
Author(s):  
Jean Baldus Patel ◽  
Debra G. B. Leonard ◽  
Xai Pan ◽  
James M. Musser ◽  
Richard E. Berman ◽  
...  

ABSTRACT We evaluated the MicroSeq 500 16S rDNA Bacterial Sequencing Kit (PE Applied Biosystems), a 500-bp sequence-based identification system, for its ability to identify clinical Mycobacterium isolates. The organism identity was determined by comparing the 16S rDNA sequence to the MicroSeq database, which consists primarily of type strain sequences. A total of 113 isolates (18 different species), previously recovered and identified by routine methods from two clinical laboratories, were analyzed by the MicroSeq method. Isolates with discordant results were analyzed by hsp65 gene sequence analysis and in some cases repeat phenotypic identification, AccuProbe rRNA hybridization (Gen-Probe, Inc., San Diego, Calif.), or high-performance liquid chromatography of mycolic acids. For 93 (82%) isolates, the MicroSeq identity was concordant with the previously reported identity. For 18 (16%) isolates, the original identification was discordant with the MicroSeq identification. Of the 18 discrepant isolates, 7 (six unique sequences) were originally misidentified by phenotypic analysis or the AccuProbe assay but were correctly identified by the MicroSeq assay. Of the 18 discrepant isolates, 11 (seven unique sequences) were unusual species that were difficult to identify by phenotypic methods and, in all but one case, by molecular methods. The remaining two isolates (2%) failed definitive phenotypic identification, but the MicroSeq assay was able to definitively identify one of these isolates. The MicroSeq identification system is an accurate and rapid method for the identification of Mycobacterium spp.


Author(s):  
Kashaf Junaid ◽  
Hasan Ejaz ◽  
Iram Asim ◽  
Sonia Younas ◽  
Humaira Yasmeen ◽  
...  

This study evaluates bacteriological profiles in ready-to-eat (RTE) foods and assesses antibiotic resistance, extended-spectrum β-lactamase (ESBL) production by gram-negative bacteria, and heavy metal tolerance. In total, 436 retail food samples were collected and cultured. The isolates were screened for ESBL production and molecular detection of ESBL-encoding genes. Furthermore, all isolates were evaluated for heavy metal tolerance. From 352 culture-positive samples, 406 g-negative bacteria were identified. Raw food samples were more often contaminated than refined food (84.71% vs. 76.32%). The predominant isolates were Klebsiella pneumoniae (n = 76), Enterobacter cloacae (n = 58), and Escherichia coli (n = 56). Overall, the percentage of ESBL producers was higher in raw food samples, although higher occurrences of ESBL-producing E. coli (p = 0.01) and Pseudomonas aeruginosa (p = 0.02) were observed in processed food samples. However, the prevalence of ESBL-producing Citrobacter freundii in raw food samples was high (p = 0.03). Among the isolates, 55% were blaCTX-M, 26% were blaSHV, and 19% were blaTEM. Notably, heavy metal resistance was highly prevalent in ESBL producers. These findings demonstrate that retail food samples are exposed to contaminants including antibiotics and heavy metals, endangering consumers.


2015 ◽  
Vol 59 (4) ◽  
pp. 1962-1968 ◽  
Author(s):  
Sun Hee Park ◽  
Su-Mi Choi ◽  
Dong-Gun Lee ◽  
Sung-Yeon Cho ◽  
Hyo-Jin Lee ◽  
...  

ABSTRACTExtended-spectrum β-lactamase-producingEscherichia coli(ESBL-EC) is increasingly identified as a cause of acute pyelonephritis (APN) among patients without recent health care contact, i.e., community-associated APN. This case-control study compared 75 cases of community-associated ESBL-EC APN (CA-ESBL) to 225 controls of community-associated non-ESBL-EC APN (CA-non-ESBL) to identify the risk factors for ESBL-EC acquisition and investigate the impact of ESBL on the treatment outcomes of community-associated APN (CA-APN) caused byE. coliat a Korean hospital during 2007 to 2013. The baseline characteristics were similar between the cases and controls; the risk factors for ESBL-EC were age (>55 years), antibiotic use within the previous year, and diabetes with recurrent APN. The severity of illness did not differ between CA-ESBL and CA-non-ESBL (Acute Physiology and Chronic Health Evaluation [APACHE] II scores [mean ± standard deviation], 7.7 ± 5.9 versus 6.4 ± 5.3;P= 0.071). The proportions of clinical (odds ratio [OR], 1.76; 95% confidence interval [CI], 0.57 to 5.38;P= 0.323) and microbiological (OR, 1.16; 95% CI, 0.51 to 2.65;P= 0.730) cures were similar, although the CA-ESBL APN patients were less likely to receive appropriate antibiotics within 48 h. A multivariable Cox proportional hazards analysis of the prognostic factors for CA-APN caused byE. colishowed that ESBL production was not a significant factor for clinical (hazard ratio [HR], 0.39; 95% CI, 0.12 to 1.30;P= 0.126) or microbiological (HR, 0.49; 95% CI, 0.21 to 1.12;P= 0.091) failure. The estimates did not change after incorporating weights calculated using propensity scores for acquiring ESBL-EC. Therefore, ESBL production did not negatively affect treatment outcomes among patients with community-associatedE. coliAPN.


2021 ◽  
Vol 37 (2) ◽  
pp. 113-125
Author(s):  
M.K Salihu ◽  
A Yarima ◽  
H.I Atta

1983. These enzymes possess the ability to inactivate susceptible β-lactam antibiotics i.e. penicillins, first, second and third generation cephalosporins and aztreonam, but not cephamycins and carbapenems . Their mode of action is by hydrolyzing the β-lactam ring. Even before the first β-lactam antibiotic (penicillin) was developed, resistance to β-lactam antibiotics was observed . ESBL genes are plasmids- and transposons- mediated, as such, can be spread easily to other species of bacteria. Resistance of ESBL- producing bacteria to the β-lactam antibiotics is a continuing cause of public health problems , it is increasingly being observed in community and nosocomial acquired infections. Detection and identification of these ESBLs in the laboratory is of prime importance for the selection of appropriate antibiotics to be used in the treatment of infections caused by ESBL- producing bacteria. The aim of this review is to explain in detail , several phenotypic methods used in the detection and confirmation of extended spectrum β lactamases. Keywords: Antibiotic resistance, ESBL, bacteria, phenotypic method


2021 ◽  
Vol 6 (2) ◽  
pp. 1-7
Author(s):  
Eze EM

Background: This study investigated the prevalence of extended spectrum beta-lactamase producing enterobacteriaceae in Illorin metropolis using standard methods. The prevalence of ESBLs is increasingly being reported worldwide, and it varies according to geographic location and is directly linked to the use and misuse of antibiotics extended spectrum lactamases (ESBLs) are a major challenge in hospitalized patients worldwide and cause epidemic outbreaks in health care facilities, spreading in the community leading to various infections. Objectives: Screen for the extended spectrum β-lactamase producing Enterobacteriaceae and also determine the prevalence of ESBL producing Enterobacteriaceae in relation to gender, age and sample source. Methods: One hundred and sixty eight samples collected from routine clinical specimen such as high vagina swabs, urine, urethra swabs and wound swabs and sputum from October to December 2018 were studied. Fifty two enterobacteriaceae were isolated using spread plate method on macConkey and Cystein lactose electrolyte deficient media. The organisms were Klebsiella pneumoniae, Escherichia coli, Salmonella sp, Shigella sp, and Proteus sp. The isolates were subjected to antibiotic susceptibility testing using modified Kirby-Bauer standardized disc diffusion method. The antibiotics used were ceftazidine (30ug), cefuroxime (30ug), gentamicin (10ug), ciprofloxacin (5ug), ofloxacin 5ug, amoxicillin/clavulanate 30ug, nitrofurantoin 30ug and ampicillin 10ug. Ceftazidime showed a susceptibility percentage of 84.6%,, cefuroxime 61.5%, gentamicin 71.2% ciprofloxacin 46.2%, ofloxacin 51.9%, augmentin 61.5%, nitrofurantoin 71.2% and ampicillin, 44.2% with a significant difference (P< 0.05).Extended spectrum beta-lactamase ESBL, production by clinical and laboratory standards institute (CLSI) methods showed that 15(28.9%) of isolates belonging to the genera Escherichia, Klebsiella and Proteus expressed ESBL production. The order of ESBL production by the isolates were Escherichia coli 9 (17.3%), Klebsiella pneumonia 5(9.3%) and Proteus 1(1.9%). Thus, attention needs to be given by health care personnel’s to ESBL producing organisms in order to reduce the spread.


2019 ◽  
Author(s):  
Zhihui Chang ◽  
Yue Ren ◽  
Hairui Wang ◽  
Zhaoyu Liu

Abstract Background The pathogenic bacterium Klebsiella pneumoniae (KP) is the major causative agent of pyogenic liver abscess (PLA). But reports about the prognosis of KP-caused PLA (KPLA) are rare. This study aimed to ascertain the recurrence rate of KPLA after initial treatment, and its contributing factors.Methods The medical records data were retrospectively analyzed of KPLA patients who were admitted to Shengjing Hospital of China Medical University from January 2012 to January 2018. According to whether or not there was recurrence of KPLA during follow-up, the patients were divided into a ‘recurrence’ and a ‘non-recurrence’ group. The clinical and CT characteristics of patients were compared between the two groups, and those factors related to KPLA recurrence were further analyzed.Results A total of 110 patients who had first-time episodes of KPLA were included into the study. The average follow-up time was 3.65±2.18 years. Twenty (18.18%) KPLA patients experienced recurrence. Those in the recurrence group had a significantly greater incidence of extended-spectrum β-lactamase (ESBL) production compared to the non-recurrence group (30.0% vs 8.89%, P=0.018). Diabetes, biliary tract disease, and history of malignancy was not associated with recurrence (all P>0.05). No difference in the CT characteristics of KPLA (including abscess size, location, whether multilocular, gas production of KPLA, and thrombophlebitis) was found between the two groups. Multivariate regression analysis showed that ESBL production (OR, 6.3; 95% CI, 1.02–38.59; P=0.04) was an independent risk factor for the recurrence of KPLA.Conclusions KPLA has a high recurrence rate, and ESBL production is a risk factor for recurrent KPLA.


2004 ◽  
Vol 48 (8) ◽  
pp. 3159-3161 ◽  
Author(s):  
Hyunjoo Pai ◽  
Jung Yun Hong ◽  
Jeong-Hum Byeon ◽  
Yun-Kyung Kim ◽  
Hoan-Jong Lee

ABSTRACT Of 72 blood isolates of Enterobacter spp. collected over an 8-year period, 50% (36 of 72) were derepressed or partially derepressed AmpC mutants. The extended-spectrum β-lactamase (ESBL) production rate was 43% (31 of 72 isolates), and 67.3% (31 of 46) of extended-spectrum cephalosporin-resistant strains produced ESBLs. Thus, a confirmatory test for ESBL production is necessary for extended-spectrum cephalosporin-resistant Enterobacter spp.


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