Comparison of in vitro efficacy of ertapenem, imipenem and meropenem in the infections caused by the Enterobacteriaceae strains family.

Comparison of in vitro efficacy of ertapenem, imipenem and meropenem in the infections caused by the Enterobacteriaceae strains family.

Anaesthesiol Intensive Ther. 2013 Apr-Jun;45(2):67-72

Authors: Guzek A, Tomaszewski D, Rybicki Z, Truszczyński A, Barański M, Korzeniewski K

Abstract
BACKGROUND: The members of the bacterial Enterobacteriaceae family play an important role in the aetiology of many hospital infections. Some of them are able to produce β-lactamase, an enzyme which induces the resistance of those bacteria to penicillins, cephalosporins and, in severe infections, to penicillins with β-lactamase inhibitors. In this situation, the carbapenems become the drugs of choice. The objective of this study was to analyse the in vitro efficacy of three carbapenems: ertapenem, imipenem and meropenem against bacterial species of the Enterobacteriaceae family.
METHODS: A total of 99 bacterial species (including ten bacterial species producing the ESBL mechanism), isolated between September 2011 and March 2012 from diagnostic material collected from patients of surgical clinics in the department of motoskeletal system infections and the critical care unit, hospitalised in the Military Institute of Medicine in Warsaw, were analysed. The values of MIC 50 and MIC 90 were recorded.
RESULTS: All isolated bacterial species were susceptible to meropenem. One strain of Morganella morganii was resistant to imipenem, while one strain of Enterobacter cloaceae and one strain of Klebsiella pneumoniae were resistant to ertapenem. In the Enterobacteriaceae ESBL(-) group, the values of MIC 50 were 0.006 μg mL-1 for ertapenem, 0.19 μg mL⁻¹ for imipenem, and 0.032 μg mL⁻¹ for meropenem, and the MIC 90 values were: 0.25 μg mL⁻¹, 0.5 μg mL⁻¹ and 0.125 μg mL⁻¹, respectively. In the Enterobacteriaceae ESBL(+) group, the values of MIC 50 were 0.38 μg mL⁻¹, 0.25 μg mL⁻¹, 0.064 μg mL⁻¹, and the values of MIC 90 were 0.5 μg mL⁻¹, 0.25 μg mL⁻¹ and 0.125 μg mL⁻¹, respectively.
CONCLUSIONS: All analysed carbapenems had high in vitro efficacy against both Enterobacteriaceae ESBL(-) and Enterobacteriaceae ESBL(+) bacterial species.

PMID: 23877897 [PubMed – in process]

Antibiotic rotation for febrile neutropenic patients with hematological malignancies: clinical significance of antibiotic heterogeneity.

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Antibiotic rotation for febrile neutropenic patients with hematological malignancies: clinical significance of antibiotic heterogeneity.

PLoS One. 2013;8(1):e54190

Authors: Chong Y, Shimoda S, Yakushiji H, Ito Y, Miyamoto T, Kamimura T, Shimono N, Akashi K

Abstract
BACKGROUND: Our unit adopted the single administration of cefepime as the initial treatment for febrile episodes in neutropenic patients with hematological malignancies. However, recently, cefepime-resistant gram-negative bacteremia, including those with extended-spectrum β-lactamase (ESBL)-producers, was frequently observed in these patients. Therefore, we instituted a rotation of primary antibiotics for febrile neutropenic patients in an attempt to control antibiotic resistance.
METHODS: This prospective trial was performed from August 2008 through March 2011 at our unit. After a pre-intervention period, in which cefepime was used as the initial agent for febrile neutropenia, 4 primary antibiotics, namely, piperacillin-tazobactam, ciprofloxacin, meropenem, and cefepime, were rotated at 1-month intervals over 20 months. Blood and surveillance cultures were conducted for febrile episodes, in order to assess the etiology, the resistance pattern (particularly to cefepime), and the prognosis.
RESULTS: In this trial, 219 patients were registered. A 65.9% reduction in the use of cefepime occurred after the antibiotic rotation. In the surveillance stool cultures, the detection rate of cefepime-resistant gram-negative isolates, of which ESBL-producers were predominant, declined significantly after the intervention (8.5 vs 0.9 episodes per 1000 patient days before and after intervention respectively, P<0.01). Interestingly, ESBL-related bacteremia was not detected after the initiation of the trial (1.7 vs 0.0 episodes per 1000 patient days before and after intervention respectively, P<0.01). Infection-related mortality was comparable between the 2 periods.
CONCLUSIONS: We implemented a monthly rotation of primary antibiotics for febrile neutropenic patients. An antibiotic heterogeneity strategy, mainly performed as a cycling regimen, would be useful for controlling antimicrobial resistance among patients treated for febrile neutropenia.

PMID: 23372683 [PubMed – indexed for MEDLINE]

Outbreak Caused by an Ertapenem-Resistant, CTX-M-15-Producing Klebsiella pneumoniae ST101 Clone Carrying an OmpK36 Porin Variant.

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Outbreak Caused by an Ertapenem-Resistant, CTX-M-15-Producing Klebsiella pneumoniae ST101 Clone Carrying an OmpK36 Porin Variant.

J Clin Microbiol. 2013 Jul 12;

Authors: Poulou A, Voulgari E, Vrioni G, Koumaki V, Xidopoulos G, Chatzipantazi V, Markou F, Tsakris A

Abstract
Although numerous studies have documented outbreaks of carbapenem-resistant Klebsiella pneumoniae (CRKP) possessing various carbapenemases, reports on outbreaks due to CRKP possessing extended-spectrum β-lactamases (ESBLs) and/or AmpCs with porin lesions are limited. We describe an outbreak caused by an ertapenem-resistant, CTX-M-15-producing K. pneumoniae clonal strain expressing an OmpK36 porin variant. From May 2012-November 2012, 37 ertapenem-resistant, phenotypically-negative for carbapenemase production K. pneumoniae isolates were recovered from 19 patients hospitalized in the intensive care unit of a Greek hospital. The isolates were either susceptible or intermediate to other carbapenems and resistant to all remaining β-lactams but cefotetan. Phenotypic and molecular analysis revealed in all isolates the presence of blaCTX-M-15 gene on a conjugative 100-kb plasmid, disruption in the expression of the ompK35 gene and the production of an Ompk36 porin variant. The index case was a patient admitted from another hospital. Active surveillance upon admission and on a weekly basis was immediately initiated; environmental samples were also periodically tested. Molecular typing showed that all clinical isolates as well as two ertapenem-resistant K. pneumoniae environmental isolates belonged to the same clonal type and were assigned to MLST sequence type ST101. As all colonized/infected patients were hospitalized in overlapping periods, cross-infection was considered as the main route for the dissemination of the outbreak strain. Despite reinforcement of infection control measures and active surveillance the outbreak lasted approximately 7 months. Identification of hidden carriers upon admission and by screening on weekly basis was found valuable for early recognition and subsequent successful management of the outbreak.

PMID: 23850951 [PubMed – as supplied by publisher]

Etiology, Extended-spectrum β-lactamase Rates and Antimicrobial Susceptibility of Gram-negative Bacilli Causing Intra-abdominal Infections in Patients in General Pediatric and Pediatric Intensive Care Units-Global Data From The Study for Monitoring Antimicrobial Resistance Trends 2008 to 2010.

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Etiology, Extended-spectrum β-lactamase Rates and Antimicrobial Susceptibility of Gram-negative Bacilli Causing Intra-abdominal Infections in Patients in General Pediatric and Pediatric Intensive Care Units-Global Data From The Study for Monitoring Antimicrobial Resistance Trends 2008 to 2010.

Pediatr Infect Dis J. 2013 Jun;32(6):636-40

Authors: Badal RE, Bouchillon SK, Lob SH, Hackel MA, Hawser SP, Hoban DJ

Abstract
BACKGROUND: Antimicrobial resistance has been increasing for several years and is often higher in intensive care units (ICUs) than in other facilities. The spread of extended-spectrum β-lactamases (ESBLs) in particular has profoundly impacted antimicrobial efficacy and usage. The Study for Monitoring Antimicrobial Resistance Trends has monitored the in vitro activity of ertapenem and several comparators against aerobic gram-negative bacteria from intra-abdominal infections (IAIs) for many years. This report summarizes susceptibility levels and epidemiology for key IAI pathogens cultured from general pediatric medical wards and pediatric ICUs globally.
METHODS: 1248 gram-negative bacteria were collected from pediatric IAIs by 113 labs in 40 countries from 2008 to 2010. Susceptibility was determined by Clinical and Laboratory Standards Institute broth microdilution. Susceptibility rates (%S) were determined for species with ≥10 isolates.
RESULTS: Sixty-two percent of isolates came from general pediatric wards and 38% from pediatric ICUs. The overall ESBL-positive rate was 11.0% for Escherichia coli and 38.9% for Klebsiella pneumoniae; the ESBL-positive rate for E. coli was twice as high in ICU as non-ICU. Most study drugs inhibited >90% of ESBL-negative isolates, but only the carbapenems inhibited >90% of ESBL-positive E. coli and only imipenem inhibited >90% of ESBL-positive K. pneumoniae.
CONCLUSIONS: Amikacin, imipenem and ertapenem were the most active against gram-negative bacteria from pediatric IAIs, followed closely by the fluoroquinolones and cefepime. Other cephalosporins were often <90% active. ESBL rates were 38.9% for K. pneumoniae and 11.0% for E. coli. Therapy for pediatric IAIs should take into consideration local ESBL rates because only carbapenems inhibited most of these pathogens.

PMID: 23838732 [PubMed – in process]

Rise of community-onset urinary tract infection caused by extended-spectrum β-lactamase-producing Escherichia coli in children.

Rise of community-onset urinary tract infection caused by extended-spectrum β-lactamase-producing Escherichia coli in children.

J Microbiol Immunol Infect. 2013 Jul 5;

Authors: Fan NC, Chen HH, Chen CL, Ou LS, Lin TY, Tsai MH, Chiu CH

Abstract
BACKGROUND: Urinary tract infection (UTI) caused by resistant bacteria is becoming more prevalent. Few studies are available regarding community-onset UTIs caused by extended-spectrum β-lactamase (ESBL)-producing bacteria in children.
MATERIALS AND METHODS: During a 5-year period, hospitalized children with community-onset UTI caused by ESBL-producing Escherichia coli (case) and those with non-ESBL-producing E. coli (control) were identified. Patients with long-term care facility stay within the preceding month and those with urine cultures obtained >72 hours after admission were excluded. Clinical features and risk factors associated with the occurrence of ESBL-producing E. coli UTI were reviewed.
RESULTS: The prevalence of UTI due to ESBL-producing E. coli increased slightly from 0.59% in 2002 to 0.96% in 2006. A total of 104 cases and 208 controls were included for comparison. The ciprofloxacin resistance of the ESBL-producing E. coli increased significantly in this period (p = 0.006). Pre-existing neurological diseases (p < 0.001), use of antibiotics in the past 3 months (p < 0.001), and recent hospitalization within 1 month (p < 0.001) were found to be potential risk factors. Moreover, previous exposure to third-generation cephalosporins (p < 0.001) and aminoglycosides (p < 0.001) was associated with the selection of ESBL-producing E. coli. Children with ESBL-producing E. coli UTIs had a longer hospital stay (p = 0.031) than those without.
CONCLUSIONS: ESBL-producing E. coli gradually became coresistant to other broad-spectrum antibiotics, notably ciprofloxacin. UTIs caused by such resistant organisms led to a longer hospital stay and more antibiotic use. Reinforcement of infection control measures, especially hand washing in childcare settings and antibiotic stewardship, is critical to reduce the spread of ESBL-producing E. coli.

PMID: 23834784 [PubMed – as supplied by publisher]