ESBL Positivity Research Articles

Characterization of the population structure, drug resistance mechanisms and plasmids of the community-associated Enterobacter cloacae complex in China

To investigate the population structure, drug resistance mechanisms and plasmids of community-associated Enterobacter cloacae complex (CA-ECC) isolates in China. Sixty-two CA-ECC isolates collected from 31 hospitals across China were typed by hsp60 typing and MLST. ESBL and AmpC-overexpression phenotype was determined by double-disc synergy test. Replicon typing and conjugation were performed for plasmid analysis. All ESBL-positive isolates and representative conjugants were subjected to detailed characterization by WGS. Enterobacter hormaechei and Enterobacter kobei were predominant in our collections. MLST distinguished 46 STs with a polyclonal structure. ST591 was the most prevalent clone detected in northern China. Twenty-two isolates (35.5%) were ESBL positive and half of them were E. kobei. ESBL positivity was related to ESBL production (15/22) and to AmpC overexpression (18/22). Core-genome phylogenetic analysis identified intra- and inter-regional dissemination of ESBL-producing E. kobei clones. ESBL producers were exclusively classified as E. hormaechei and E. kobei, and blaCTX-M-3 was the most prevalent ESBL genotype (10/15) detected in four different environments. In the ESBL-positive population, the ESBL producers encoded more drug resistance genes (8-24 genes) by carrying more plasmids (1-3 plasmids) than the non-ESBL-producing isolates, resulting in an inter-group difference in drug susceptibilities. IncHI-type plasmids were prevalent in the ESBL producers (12/15). All IncHI2-type plasmids (n = 11) carried ESBL genes and shared a similar backbone to p09-036813-1A_261 recovered from Salmonella enterica in Canada. The species-specific distribution, species-dependent ESBL mechanism and endemic plasmids identified in our study highlight the necessity for tailored surveillance of CA-ECC in the future.

Antimicrobial susceptibility of extended-spectrum beta-lactamase producing <i>Enterobacteriaceae</i> causing urinary tract infections in Ouagadougou, Burkina Faso

Objective: To determine the frequency of extended-spectrum beta lactamase producing Enterobacteriaceae (ESBL) and other antibioticsresistant bacteria in urinary tract isolates.Study Design: prospective and experimental study.Methodology: Place and duration of study :YalgadoOuedraogo University Hospital Center, Charles De Gaulle Pediatric Hospital Center, Saint Camille Hospital and National Public Health Laboratory, Ouagadougou, from November 2014 to October 2015.AllEnterobacteriaceaestrains isolated from urinary samples of patients were identifiedusing API 20E chemical gallery (BioMerieux, France). All strains were subjected to an array of 14 antibiotics to study their drug susceptibility by using Kirby- Baeurdisk diffusion method. Detection of ESBL was carried out by double disk diffusion technique. Statistical analysis was performed by Microsoft Excel and Anova one-way GrapPad Prism version 5.01. Chi-square (χ2) test was used to determine significance. A p˂ 0.05was considered to be statistically significant.Results: A total of 324 isolates of Enterobacteriaceae were identified during the study period, including211(65%) E. coli, 75 (23%)Klebsiella spp., 18 (6%) Enterobacter spp., 11 (3%)Proteus spp., 5 (2%) Citrobacter spp., Serratia spp. 3 (1%).All the clinical isolates were susceptible to imipenem. Resistance to amikacinwas 14% (45/324); gentamicin 54% (175/324); tobramycin 58% (187/324); nalidixic acid 72% (234/324),ciprofloxacin 63% (204/324) and to cotrimoxazole 83% (269/324).The overall rate of the EBSL producing strains was 35% (114/324). Their susceptibility to antibiotics was (imipenem,amikacin, cefoxitin and fosfomycin) 100% (114/114), 93% (106/114), 74% (84/114) and 84% (96/114) respectively. ESBL positivity within individual organism group was highest inEscherichia coli 64% (73/324) followed byKlebsiellaspp. 28% (32/324), Enterobacterspp. 3% (4/324), Proteus spp. and Citrobacterspp. 2% (2/324).Conclusion: The results showeda high frequency of ESBL producing Enterobacteriaceae, especially Escherichia coli and Klebsiellaspp. The data points to theneed of routine detection and surveillance of ESBL producing bacteria in Burkina Faso.Keywords: Antimicrobial susceptibility, Enterobacteriaceae, Urine, Burkina Faso

ESBL Positive Organisms: Method of Routine Reporting and Prevalence in Health Care Settings

Extended Spectrum ß- Lactamase (ESBL) acquired by bacteria is a highly effective weapon for drug resistance against a wide range of antibiotics (penicillins, cephalosporins and monobactams). ESBLs have continued to increase in variety and prevalence and are now a global health concern including Bangladesh. They are associated with failure in effective treatment, increased morbidity and mortality, poor outcomes, increases in length of stay (LOS) in hospital and health care costs. So, it is important to identify it and take necessary measures to treat with appropriate antimicrobial therapy. This study has been designed to establish an easy method for routine reporting of ESBL organisms and notify it's incidence in Health Care settings. Double Disk Diffusion Test, utilizing Cefotaxime, Amoxicillin/Clavulanic acid and Ceftazidime, was used as Screening Test. Phenotypic Confirmatory Test was done for confirmation of screening ESBL positive organisms. Four hundred seventy two organisms (Escherichia coli and Klebsiella sp.) were isolated from urine and pus collected from Health Care settings. Only 50 screening ESBL positive organisms and 50 ESBL negative organisms were tested by Phenotypic Confirmatory Test. All of them were positive and negative respectively by Phenotypic Confirmatory Test. Predominant organism among the isolates was Escherichia coli (82.8%) of which 54.4% were ESBL positive followed by Klebsiella sp. (17.2%) of which 44.4% were ESBL positive. ESBL positivity was more in hospital infections (73.3%) than in community acquiredinfections (44.5%).Bangladesh J Med Microbiol 2014; 08 (02): 23-27

Distribution of CTX-M group I and group III β-lactamases produced by Escherichia coli and klebsiella pneumoniae in Lahore, Pakistan.

Extended-spectrum-lactamases (ESBLs) of the CTX-M type is worrisome issue in many countries of the world from past decade. But little is known about CTX-M beta-lactamase producing bacteria in Pakistan. Therefore, this study was carried out to investigate the distribution of CTX-M beta-lactamase producing E.coli and Klebsiella pneumoniae using phenotypic and molecular techniques. A total of 638 E.coli and 338 Klebsiella pneumoniae were isolated from patients attending two hospitals and one diagnostic Centre in Pakistan during 2013-2015. ESBL production was screened by double disc synergism, combination disc (cefotaxime and ceftazidime with clavulanic acid) and E-test. These strains were further characterized by PCR (CTX-M I, CTX-M III) and sequencing. After ribotyping of strains accession numbers were obtained. These isolates were highly resistant to cephalosporins, ceftazidime, cefotaxime, aztreonam, and cefuroxime but susceptible to carbapenems, sulfzone, amikacin and tazocin. Multiple antibiotic resistances index (MAR) revealed that 51% of E.coli strains fell in the range of 0.61-0.7 and 39% of Klebsiella pneumoniae strains fell in the range of 0.71-0.8. 64% Double disc synergism (DDS), 76.4% combination disc (CD), 74% E-test showed ESBL positivity in strains. In E.coli ESBL genes blaCTX-M-I and blaCTX-M-III were detected in 212 (72.1%) and 25 (8.5%) respectively. In Klebsiella pneumoniae ESBL genes blaCTX-M-I and blaCTX-M-III were detected in 89 (82.4%) and 10 (9.2%). Combination of both genes blaCTX-M-I and blaCTX-M-III were found in 16 (5.4%) of E.coli strains and 5 (4.6%) of Klebsiella pneumoniae strains. Sequencing revealed that CTXM-15 was predominately present in the CTX-M-I group. The prevalence of ESBL producing E.coli and Klebsiella pneumoniae isolates was high and the majority of them positive for blaCTX-M-I as compared to blaCTX-M-III. These findings highlight the need to further investigate the epidemiology of other CTX-M beta-lactamases in Pakistan.

Phenotypic and Genotypic Characterization of Extended-spectrum beta-lactamase Producing Escherichia coli and Klebsiella species Isolated from a Tertiary Care Hospital in Bangladesh

This study was conducted to determine the presence of ESBL producing Escherichia coli and Klebsiella species in a tertiary care hospital of Bangladesh, as well as to observe the patterns of antibiotic resistance and antibiotic resistance genes among them. A total of 166 Escherichia coli,Klebsiella pneumoniae and Klebsiella oxytoca were isolated from urine, wound swab, pus, sputum and blood samples of patients of Dhaka Medical College Hospital. Antibiotic susceptibility test wasperformed by disk-diffusion technique. ESBL producers were detected phenotypically by Double-disk synergy (DDS) test. Genotypically ESBL genes (blaCTX-M-15, blaOXA-1) among the ESBL producers with presence of class 1 integron among them were detected by PCR. Eighty seven (52.41%) ESBL producers were detected by DDS test. CTX-M-15 (80.46%) was the dominant genotype in ESBL producing strains detected by PCR. Class 1 integron was found in 58 (66.67%) of the phenotypic positive ESBL producers. The results of this study showed high proportion of ESBL producing Escherichia coli and Klebsiella species in Bangladesh.
 Bangladesh J Med Microbiol 2016; 10 (2): 4-8

Impact of extended-spectrum β-lactamase on clinical outcome and medical cost in patients with bloodstream infection due to Klebsiella pneumoniae

To evaluate the impact of extended-spectrum β-lactamase (ESBL) on clinical outcome and medical cost in patients with bloodstream infection (BSI) due to Klebsiella pneumoniae. A retrospective study was conducted in patients admitted into Changhai Hospital between January 2013 and December 2014, who suffered from BSI due to Klebsiella pneumoniae during hospitalization. Patients were divided into two groups according to whether Klebsiella pneumoniae produced ESBL (ESBL positive group and ESBL negative group). They were matched with propensity score matching method in a 1∶1 ratio and then multiple regression model was used to analyze the impact of ESBL on clinical outcome and medical cost. Clinical outcome was evaluated by 30-day mortality post BSI; medical cost was evaluated by total length of stay (LOS), post-BSI LOS, total hospital cost and antimicrobial cost. Before matching, the two groups were significantly different in age, nosocomial infection rate, LOS before BSI and surgical rate during hospitalization (all P<0.05). The ESBL-positive group had higher 30-day mortality post BSI (21.3% vs 8.7%, P=0.054), and higher total LOS [25.0(12.0, 33.0) vs 16.0(10.0, 23.0) d, P=0.015], post-BSI LOS [16.0(9.0, 26.0) vs 10.0(5.0, 16.0) d, P=0.006], total hospital cost [69 409(40 605, 198 021) vs 45 683(28 448, 67 000) ￥, P<0.001] and antimicrobial cost [10 279(4 815, 25 500) vs 3 783(1 596, 11 879) ￥, P<0.001]. After matching, the two groups had no significant differences in clinical characteristics such as sex, age, nosocomial infection rate, LOS before BSI, APACHEⅡ score, Charlson Comorbidity Index, underlying diseases and surgical rate during hospitalization (all P>0.05). Multiple regression analysis indicated that ESBL could significantly increase the total LOS, post-BSI LOS, total hospital cost and antimicrobial cost (all P<0.001), but did not increase the 30-day mortality post BSI (P=0.910). ESBL can significantly increase the medical cost in patients with BSI due to Klebsiella pneumoniae but does not increase the 30-day mortality post BSI.

A Modified Boronic Acid (MBA) Disc Potentiation Assay for Detection of Extended Spectrum ?-Lactamase (ESBL) Producing Bacteria

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

Clinical features and antibiotic resistance of Escherichia coli bloodstream infections in children

To analyze risk factors, clinical features, outcomes and antibiotic resistance of Escherichia coli(E.coli) causing bloodstream infections in children. All inpatients with E. coli positive blood culture in Beijing Children's Hospital from January 2012 to May 2014 were enrolled; 112 cases were included, 66 cases (58.9%) were male, and 46 cases(41.1%) were female. Age range was 2 days to 16 years. Among them, 43 cases (38.4%) were neonates, 19 cases (17.0%) aged from 1 month to 1 year, 14 cases (12.5%) were 1-3 years old, and 36 cases (32.1%) were over three years old. We analyzed the divisions to which the patients were admitted, source of infection, underlying diseases, clinical characteristics, antibiotic resistance, and treatment outcomes, etc. Forty-six cases (41.1%) were treated in division of hematology, 42 (37.5%) in neonatology, 9 (8.0%) in internal medicine, 8 (7.1%) in surgery, and 7 (6.3%) in pediatric intensive care unit. Sixty-five cases(58.0%) had underlying diseases. Fever was the most frequently presented symptom, as it was seen in 91 cases (81.3%); 52 cases(46.4%) had respiratory symptoms. Among these, 43 cases had pneumonia, 3 cases had respiratory failure, 3 cases were diagnosed as upper respiratory tract infection, 2 had pulmonary hemorrhage and 1 case had bronchitis. Twenty-six cases (23.2%)were diagnosed as severe sepsis and purulent meningitis separately, 14 cases(12.5%) had urinary tract infection. There were 73 (65.2%) strains inducing extended spectrum β-lactamases (ESBLs), of which 6 (8.2%) and 10 (13.7%) strains were resistant to amikacin and carbapenems respectively. Resistance rate against other antimicrobial agents varied from 64.6% to 100%. 92 (82.1%) cases were cured or had improvement while 20 patients (17.9%) died or could not be cured at the end of treatment. Positive ESBLs (χ(2) = 6.609, P = 0.010), being complicated with severe sepsis (χ(2) = 40.253, P = 0.000) and requiring mechanical ventilation (χ(2) = 34.441, P = 0.000) indicate poor prognosis. Patients with underlying diseases and newborns are susceptible to E. coli bloodstream infection. ESBLs infection, severe sepsis and mechanical ventilation indicate poor prognosis in E. coli blood stream infection. Clinicians may use carbapenems as empirical treatment for ESBLs infection. There may be carbapenem-resistant enterobacteriaceae strains infection if patients receiving treatment with carbapenems have no response.

Evaluation of Diagnostic Performance of RAPIDEC CARBA NP Test for Carbapenemase-ProducingEnterobacteriaceae

Background: Extended-spectrum β-lactamase (ESBL)producing Enterobacteriaceae are resistant to most β-lactam antibiotics except carbapenems. In recent years, infrequently isolated Enterobacteriaceae that produce carbapenemase pose a serious threat in the selection of appropriate therapeutic antibiotics. The rapid detection method of carbapenemase-producing Enterobacteriaceae (CPE) is necessary to prevent the spread of CPE into healthcare facilities. Methods: One hundred clinical Enterobacteriaceae isolates (Klebsiella pneumoniae 40, Escherichia coli 40, others 20) showing susceptibility to carbapenems and positivity in the CLSI ESBL phenotypic test from November 2015 to March 2016 and 59 stocked Enterobacteriaceae isolates harboring resistance genes producing carbapenemase (K. pneumoniae 56, Enterobacter cloacae 2, E. coli 1; types of CPE: KPC 36, GES 12, NDM 6, VIM 2, OXA 2, IMP 1) were subjected to the RAPIDEC CARBA NP test (bioMerieux, France) and CPE phenotypic test using the modified Hodge test (MHT) and carbapenemase inhibition test. Results: All of the 100 Enterobacteriaceae isolates with carbapenem susceptibility and ESBL positivity were negative on the RAPIDEC CARBA NP test and CPE phenotypic test. Of 59 stock CPE isolates, 53 and 42 showed positive results to the RAPIDEC CARBA NP test and MHT, respectively. The sensitivity and specificity of the RAPIDEC CARBA NP test for detecting CPE were 89.8% and 100%, respectively. Conclusion: The RAPIDEC CARBA NP test is simple and produces a result within 3 hr. In conclusion, the test is a useful screen for detecting CPE because it shows high sensitivity and specificity for CPE detection. (Ann Clin Microbiol 2016;19:59-64)

Evaluation of blood cultures in a children's hospital located in Southeastern Anatolia.

Bloodstream infections in hospitalized patients are one of the most important causes of morbidity and mortality despite antimicrobial therapy. Early diagnosis and treatment of these infections is crucial. The aim of this study was to evaluate the distribution and antibiotic susceptibility of bacteria isolated from blood cultures in a children's hospital in the Southeastern Anatolia during an 18-month period. 7 040 blood cultures which were sent from hospitalized patients in Gaziantep Children's Hospital between 01.07.2010 and 01.01.2012 were evaluated. A total of 7 040 blood cultures were evaluated in this study. Microbial growth was detected in 2075 (29.47%) blood cultures. The most frequently isolated bacteria were coagulase-negative staphylococci (%45.97) which were followed by Salmonella spp. (%7.8). 12.12% of enterococcal isolates were resistant to glycopeptide antibiotics. The most frequently isolated gram negative bacterium was Salmonella spp. 15.43% of Salmonella spp. showed decreased susceptibility against quinolones. The ESBL positivity rate of E. coli and K. pneumoniae strains was found to be 35.08% and 57.14%, respectively. The imipenem resistance rate of P. aeruginosa was found to be 33.33%. The most common nonfermentative bacterium was S. maltophilia. The distribution of bacteria isolated from blood cultures and antibiotic resistance rates differ among different regions of Turkey. Different results obtained in our study may be related with regional tendencies to infections and patient population. Distribution of infectious agents and antibiotic resistance rates should be evaluated at regular intervals. This will lead to establishment of proper antibiotic usage policies in our country.

English

Resistance to a wide variety of common antimicrobials is observed among clinical strains designed as extended spectrum β-lactmase (ESBL) producers. They produce enzymatic protein which inactivates efficiently oxyimino cephalosporin and constitutes a serious global health concern that has complicated treatment strategies. Many studies report high prevalence of ESBL producers among Gram negative bacilli. The aim of this work was to identify the presence of TEM, SHV and CTX-M families in these strains which were initially screened by phenotypic method. Gram negative bacilli resisting third or four generation cephalosporin were isolated during anti-biogram study. The presence of ESBL positivity was detected using the double disk synergy test. Minimal inhibitory concentrations (MICs) of ceftriazon for any strain were determined using E-test manufacturing protocol. Polymerase chain reaction (PCR) analysis for β-lactamase (bla) genes of TEM, SHV and CTX-M family was carried out using designed primers in 171 ESBL isolates producers. Among 259 Gram negative bacilli collected, 171 (66, 02%) exhibited ESBL producers’ profile. Urine samples constitute major source of ESBL producers. The highest prevalence of ESBL was observed in Escherichia coli (75, 50%). Among ESBL isolates producers, gene prevalence of bla-CTX-M (65, 49%) was highest, followed by bla-TEM (25, 73%) and bla-SHV (18, 71%) in the present study. The frequency of ESBL producing strains among clinical isolates has been steadily increased. Continual drug resistance surveillance and molecular characteristics of ESBL isolates are necessary to guide the appropriate and judicious antibiotic use. Key words: Extended spectrum β-lactamase (ESBL), double disk synergy test, blaTEM, blaSHV, blaCTX-M, PCR.

Risk factors for and prophylactic effect of povidone-iodine rectal cleansing on infectious complications after prostate biopsy: a retrospective cohort study.

To evaluate the risk factors and efficacy of a povidone-iodine enema on infectious complications after transrectal ultrasound-guided prostate biopsy. A total of 814 males who underwent transrectal ultrasound-guided prostate biopsy from January 2011 to December 2013 were evaluated retrospectively. Clinical variables, including demographics, prior antibiotic, or quinolone exposure, rectal swab culture results, povidone-iodine rectal cleansing, antibiotic prophylaxis, and infectious complications, were evaluated. Overall, 16 of 814 (2.0%) patients developed infectious complications after prostate biopsy. Of the patients with infectious complications, five had fever, two had urinary tract infections, and nine had bacteremia or sepsis. Infectious complication rates were not significantly different between povidone-iodine rectal cleansing (n = 613) and no cleansing (n = 201) groups (1.5 vs. 3.5%, p = 0.083). However, povidone-iodine rectal cleansing reduced severe infectious complications such as bacteremia and sepsis (0.3 vs. 3.5%, p = 0.001). A rectal swab culture was performed in 552 patients, and extended-spectrum β-lactamase (ESBL)-producing and quinolone-resistant Escherichia coli were detected in 4.5 and 7.8% of cultures, respectively. Quinolone and antibiotic exposure within 6 months prior to prostate biopsy were associated with quinolone resistance and ESBL positivity of rectal flora and infectious complications. In the era of quinolone resistance, a povidone-iodine enema may reduce the infectious complication rate by reducing bacterial load. Quinolone exposure prior to prostate biopsy was a risk factor for antibiotic resistance to rectal flora and infectious complications.

In vitro activity of fosfomycin tromethamine against extended spectrum beta-lactamase producing urinary tract bacteria.

To determine the in vitro activity of Fosfomycin tromethamine against extended spectrum beta-lactamase producing uropathogens. Experimental study. Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi, from October 2011 to October 2012. A total of 381 culture positive ESBL producing isolates from 2400 urine samples submitted over a period of one year were included in this study. Identification of isolates was done by standard biochemical profile of the organisms. The antimicrobial susceptibility of culture positive isolates was performed by disk diffusion method as recommended by Clinical Laboratory Standard Institute guidelines (CLSI). The antimicrobial activity of Fosfomycin to various isolates revealed that 93% of E. coli, 64% Klebsiella spp. 50% Proteus spp. 75% Enterobacter cloacae, 100% Citrobacter freundii, 100% Burkholderia spp. 100% Serratia spp. and 50% Stenotrophomonas maltophilia were susceptible to this chemical compound. Fosfomycin showed excellent effectiveness to most of the common ESBL producing bacteria such as E. coli, Klebsiella and Proteus spp.

Carbapenem susceptibility among Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae isolates obtained from patients in intensive care units in Taiwan in 2005, 2007, and 2009

To investigate the evolutionary trends in non-susceptibility of carbapenems against the isolates of Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae from patients hospitalized in intensive care units (ICUs) of major teaching hospitals throughout Taiwan during 2005–2009, we applied the breakpoints of MICs recommended by Clinical and Laboratory Standards Institute and European Committee on Antimicrobial Susceptibility Testing in 2013. Escalations in imipenem MIC levels for overall E. coli and E. cloacae isolates and extended-spectrum β-lactamase (ESBL)–producing K. pneumoniae isolates were noted during this period. The overall MIC levels against imipenem and meropenem for subgroups of ESBL producers of 3 Enterobacteriaceae species were significantly higher than those of respective overall groups in 2007 and 2009. Compared with meropenem, we found that significant evidence of imipenem MIC creep and evidence of extraordinarily high rates of non-susceptibility to ertapenem among isolates of 3 species in 2009 existed. The prominent rises in rates of ertapenem non-susceptibility for ESBL-producing E. coli and K. pneumoniae during 2005–2009 and rate of ESBL positivity for E. cloacae between 4years were notably found. Based on our findings, ertapenem should be used cautiously in management of the ICU infections caused by these potentially ESBL-producing Enterobacteriaceae isolates in Taiwan.

Clinical characteristics of patients with community-acquired complicated intra-abdominal infections: A prospective, multicentre, observational study

In this prospective, observational, multicentre study using data from five countries (Columbia, The Philippines, Portugal, Taiwan and Thailand), the clinical impact of extended-spectrum β-lactamase (ESBL)-producing organisms on hospitalised patients with community-acquired complicated intra-abdominal infections (CA-cIAIs) was compared with that of non-ESBL-producing organisms during the period April 2010 to December 2011. Adult patients (aged ≥18 years) requiring surgery or percutaneous drainage were enrolled and were followed during the first hospitalisation course. An unadjusted statistical comparison of risk factors for ESBL-positive and ESBL-negative patients was performed. Multivariate regression analyses were performed to assess whether length of stay (LOS) in hospital, clinical cure rate and some important clinical characteristics were associated with ESBL positivity. During the study period, a total of 105 adult patients from five countries were enrolled, of whom 17 (16.2%) had CA-cIAI due to ESBL-positive organisms and 88 (83.8%) had CA-cIAI due to ESBL-negative organisms. Escherichia coli was isolated in 73.3% of all samples. Infections were cured in 8 (47.1%) of the patients with CA-cIAI due to ESBL-positive organisms and in 59 (67.0%) of the patients with CA-cIAI due to ESBL-negative organisms (P=0.285). The median LOS was 11.6 days for patients with infections due to ESBL-negative organisms and 17.6 days for patients with infections due to ESBL-positive organisms (P=0.011). Multivariate logistic regression analysis revealed that pre-existing co-morbidities, but not ESBL positivity, were adversely associated with clinical cure of CA-cIAIs. In contrast, duration of hospitalisation was longer for patients with CA-cIAI due to ESBL-positive organisms.

Frequency of ESBL in Surgical Site Infection at a Tertiary Care Hospital

Background: Infection caused by ESBL in the surgical site infection is very alarming. Objective: The purpose of the present study was to see the status of ESBL bacteria isolated from surgical site infection with their antimicrobial sensitivity pattern.Methodology: This cross sectional study was conducted in the Department of Microbiology at Dhaka Medical College, Dhaka from January, 2005 to December, 2005 for a period of one (1) year. All the patients presented with surgical site infections at any age with both sexes were included a study population. Detection of extended spectrum beta lactamase producing Gram negative bacteria was done by using disc diffusion method and was confirmed by E- test ESBL method. Sensitivity pattern of ESBL producers were observed against quinolone and fluoroquinolones. ESBLs are the enzymes capable of hydrolyzing all penicillin, monobactam and cephalosporins except cephamycin, but inactive against imipenem.Result: A total number of 92 surgical wound samples were collected of which 68(73.9%) samples were culture positive. Interestingly, most of the E. coli was ESBL positive (55.0%). Klebsiella species was 33.1% ESBL positive. ESBL positivity of Proteus and Pseudomonas species were low (11.1%). Among the isolated Pseudomonas species, 1(6.67%) of the 15 strains isolated from wound swab was ESBL producers. ESBL positivity was significantly found in surgically wound samples (p=0.0001). Among the ESBL producers, all the E. coli, Klebsiella species, Proteus species and Pseudomonas species were resistant to amoxicillin, cephradine, ceftriaxone, aztreonam, ceftazidime and cefotaxime. All the Gram negative bacteria were sensitive to imipenam. Conclusion: A considerable numbers of ESBL producing bacteria were detected from surgical wound.DOI: http://dx.doi.org/10.3329/jcamr.v1i2.20514 Journal of Current and Advance Medical Research Vol.1(2) 2014: 25-29

English

Extended spectrum β-lactamases (ESBLs) are emerging, diverse group of plasmid - associated antibiotic resistant enzymes that are presenting a public health concern. ESBLs were detected in Escherichia coli by performing phenotypic tests on 18 out of 35 E. coli isolates recovered from urine samples of patients with urinary tract infections in three Eygpt hospitals and identified as positive ESBLs according to CLSI screening criteria. Results of phenotypic confirmatory tests revealed that, broth microdilution test, combination disc test and double disc synergy test confirmed 14(78%), 16(89%) and 16(89 %), respectively of E. coli isolates as positive ESBLs. Genotypic screening using PCR was performed by testing for blaCTX-M, blaTEM and blaSHV enzymes. Sixteen phenotypic ESBL isolates were positive for β-lactamase genes. Ten isolates produced both blaCTX-M and blaTEM, and 6 isolates produced blaCTX-M only, while blaSHV was not detected in any isolate. The sensitivity and specificity of combination disc and broth microdilution tests compared to PCR were 100%, while double disc synergy test showed sensitivity and specificity of 87.5 and 100% respectively. ESBL isolates were found to have multi-drug resistance pattern. No correlation could be made between type of ESBL and antimicrobial susceptibility profile of the isolate. Key words: Extended spectrum β-lactamase, bla (TEM), bla (CTX-M), urinary tract infection.

Burden of Bloodstream Infection Caused by Extended-Spectrum β-Lactamase–Producing Enterobacteriaceae Determined Using Multistate Modeling at a Swiss University Hospital and a Nationwide Predictive Model

To obtain an unbiased estimate of the excess hospital length of stay (LOS) and cost attributable to extended-spectrum β-lactamase (ESBL) positivity in bloodstream infections (BSIs) due to Enterobacteriaceae. Retrospective cohort study. A 2,200-bed academic medical center in Geneva, Switzerland. Patients admitted during 2009. We used multistate modeling and Cox proportional hazards models to determine the excess LOS and adjusted end-of-LOS hazard ratio (HR) for ESBL-positive and ESBL-negative BSI. We estimated economic burden as the product of excess LOS and average bed-day cost. Patient-level accounting data provided a complementary analysis of economic burden. A predictive model was fitted to national surveillance data. Thirty ESBL-positive and 96 ESBL-negative BSI cases were included. The excess LOS attributable to ESBL-positive and ESBL-negative BSI was 9.4 (95% confidence interval [CI], 0.4-18.4) and 2.6 (95% CI, 0.7-5.9) days, respectively. ESBL positivity was therefore associated with 6.8 excess days and CHF 9,473 per BSI. The adjusted end-of-LOS HRs for ESBL-positive and ESBL-negative BSI were 0.62 (95% CI, 0.43-0.89) and 0.90 (95% CI, 0.74-1.10), respectively. After reimbursement, the average financial loss per acute care episode in ESBL-positive BSI, ESBL-negative BSI, and control cohorts was CHF 48,674, 48,131, and 13,532, respectively. Our predictive model estimated that the nationwide cost of third-generation cephalosporin resistance would increase from CHF 2,084,000 in 2010 to CHF 3,526,000 in 2015. This is the first hospital-wide analysis of excess LOS attributable to ESBL positivity determined using multistate modeling to avoid time-dependent bias. These results may inform health-economic evaluations of interventions targeting ESBL control.

Multi-centre evaluation of a phenotypic extended spectrum β-lactamase detection guideline in the routine setting

This study aimed to evaluate the routine setting performance of a guideline for phenotypic detection of extended spectrum β-lactamases (ESBLs) in Enterobacteriaceae, recommending ESBL confirmation with Etest or combination disc for isolates with a positive ESBL screen test (i.e. cefotaxime and/or ceftazidime MIC >1 mg/L or an automated system ESBL warning). Twenty laboratories submitted 443 Enterobacteriaceae with a positive ESBL screen test and their confirmation test result (74% Escherichia coli, 12% Enterobacter cloacae, 8% Klebsiella pneumoniae, 3% Proteus mirabilis, 2% Klebsiella oxytoca). Presence of ESBL genes was used as reference test. Accuracy of local phenotypic ESBL detection was 88%. The positive predictive value (PPV) of local screen tests was 70%, and differed per method (Vitek-2: 69%, Phoenix: 68%, disc diffusion: 92%), and species (95% K. pneumoniae-27% K. oxytoca). A low PPV (3%) was observed for isolates with automated system alarm but third-generation cephalosporin MICs <2 mg/L. Local ESBL confirmation had a PPV and negative predictive value (NPV) of 93% and 90%, respectively. Compared with centrally performed confirmation tests, 7% of local tests were misinterpreted. Combination disc was more specific than Etest (91% versus 61%). Confirmation tests were not reliable for P. mirabilis and K. oxytoca (PPV 33% and 38%, respectively, although NPVs were 100%). In conclusion, performance of Etests could be enhanced by education of technicians to improve their interpretation, by genotypic ESBL confirmation of P. mirabilis and K. oxytoca isolates with positive phenotypic ESBL confirmation, and by interpreting isolates with a positive ESBL alarm but an MIC <2 mg/L for cefotaxime and ceftazidime as ESBL-negative.

Prevalence and antibiogram of Extended Spectrum β-Lactamase (ESBL) producing Gram negative bacilli and further molecular characterization of ESBL producing Escherichia coli and Klebsiella spp.

Resistance to a wide variety of common antimicrobials has made the proliferation of Extended spectrum β-lactmase (ESBL) producing strains a serious global health concern that has complicated treatment strategies. The high proportion of ESBL producers among the Enterobacteriaceae and the complex molecular epidemiology with diverse types of ESBL genes are alarming. This study was undertaken to identify ESBL production in various Gram negative bacilli isolated and to further characterize ESBL producers among Escherichia coli and Klebsiella spp by PCR, which were initially screened by phenotypic method. A total of 722 isolates of Gram negative bacilli were isolated. Presence of ESBL positivity was detected using the double disk synergy test (DDST). Their antibiogram was studied. PCR analysis for β-lactamase (bla) genes of the family TEM, SHV and CTX-M was also carried out using designed primers in 20 ESBL isolates each of Escherichia coli and Klebsiella spp. Among 722 Gram negative bacilli isolated 379 (52.49%) were ESBL producers. The major source of ESBL producers were respiratory tract samples, highest ESBL production was observed in Klebsiella sp. (67.04%). Resistance to multiple classes of antibiotics was observed among ESBL producers. Among ESBL producing genes prevalence of bla-CTX-M (82.5%) was highest, followed by bla-TEM (67.5%) and bla-SHV (57.5%) in the present study. The frequency of ESBL producing strains among clinical isolates has been steadily increasing. Advance drug resistance surveillance and molecular characteristics of ESBL isolates is necessary to guide the appropriate and judicious antibiotic use.