In vitro evaluation of cefepime and other broad-spectrum beta-lactams in Taiwan medical centers. The Taiwan Antimicrobial Resistance Study Group

Epidemiology of extended-spectrum β-lactamases in Enterobacterales in Taiwan for over two decades

The emergence of antimicrobial resistance among microorganisms is a serious public health concern, and extended-spectrum β-lactamases (ESBL)-producing Enterobacterales is one of the major concerns among antibiotic-resistant bacteria. Although the prevalence of ESBL in Enterobacterales has been increasing with time, the prevalence of ESBL could differ according to the species, hospital allocation, sources of infections, nosocomial or community acquisitions, and geographic regions. Therefore, we conducted a comprehensive review of the epidemiology of ESBL-producing Enterobacterales in Taiwan. Overall, the rates of ESBL producers are higher in northern regions than in other parts of Taiwan. In addition, the genotypes of ESBL vary according to different Enterobacterales. SHV-type ESBLs (SHV-5 and SHV-12) were the major types of Enterobacter cloacae complex, but Serratia marcescens, Proteus mirabilis, Escherichia coli, and Klebsiella pneumoniae were more likely to possess CTX-M-type ESBLs (CTX-M-3 and CTX-M-14). Moreover, a clonal sequence type of O25b-ST131 has been emerging among urinary or bloodstream E. coli isolates in the community in Taiwan, and this clone was potentially associated with virulence, ESBL (CTX-M-15) production, ciprofloxacin resistance, and mortality. Finally, the evolution of the genetic traits of the ESBL-producing Enterobacterales isolates helps us confirm the interhospital and intrahospital clonal dissemination in several regions of Taiwan. In conclusion, continuous surveillance in the investigation of ESBL production among Enterobacterales is needed to establish its long-term epidemiology.

Surveillance in Taiwan Using Molecular Epidemiology for Extended-Spectrum Beta-Lactamase-ProducingKlebsiella pneumoniae

Objective:

To evaluate intrahospital and interhospital clonal dissemination of extended-spectrum beta-lactamase (ESBL)-producing strains ofKlebsiella pneumoniae.

Setting:

Eight tertiary-care university hospitals and 16 regional hospitals in Taiwan.

Methods:

Two hundred eleven confirmed ESBL-producing isolates ofK. pneumoniaewere collected from January 1998 to June 2000. The isolates were characterized by various typing methods, including antibiogram (9 antimicrobial agents), computer-based ribotyping, pulsed-field gel electrophoresis (PFGE), and isoelectric focusing of beta-lactamase.

Results:

Ribotyping identified 70 distinct ribogroups among 200 isolates evaluated. Forty-three of these ribogroups were unique. Eleven ribogroups, comprising 115 isolates, were detected in more than one hospital (interhospital dissemination), whereas 16 groups (42 isolates) were detected in more than one patient within a hospital (intrahospital dissemination). The combination of ribotyping and PFGE identified two large epidemic clones, which were called 691.5/PFGE-G and 595.7/PFGE-A. These epidemic clones were detected mainly in the hospitals located in the northern and central regions of Taiwan. However, variation of the profiles of antibiograms and isoelectric focusing was apparent within each clone. In addition, isolates with the same isoelectric focusing profile (isoelectric points 7.9, 8.2, and 8.4) and antibiogram (resistance to 9 compounds evaluated) were present among different molecular-typed clones.

Conclusions:

Our results showed that clonal dissemination (both interhospital and intrahospital dissemination) is occurring in several regions of Taiwan. Rapid computer-based ribotyping associated with PFGE demonstrated multiple epidemic clones of ESBL-producingK. pneumoniaein Taiwan. The combination of phenotypic and molecular methods has proved useful to characterize these epidemic clones.

Dissemination of extended-spectrum beta-lactamase-producing Enterobacteriaceae in intensive care units of a medical center in Taiwan

The prevalence of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae in a tertiary hospital in Taiwan was assessed over a 16-month period. A total of 125 nonrepetitive ESBL-producing isolates of Enterobacter cloacae, Escherichia coli, and Klebsiella pneumoniae were available for investigation using molecular methods. Four predominant intensive care units (ICUs) were identified, and SHV-12 (59%), CTX-M- 3 (36%), and CTX-M-14 (14%) were the three most frequent ESBLs. SHV-12 was predominant among E. cloacae in the burn unit and K. pneumoniae in the other three chest medicine-related ICUs. CTX-M-3 was predominant among E. coli and K. pneumoniae in three other ICUs. The dissemination of ESBL-producing Enterobacteriaceae in four ICUs of a medical center in Taiwan is a consequence of the clonal dissemination of a few epidemic strains along with the horizontal transmission of resistance genes-carrying plasmids among bacterial organisms.

Management of serious nosocomial bacterial infections: do current therapeutic options meet the need?

Hospital-acquired bacterial infections pose a formidable challenge for healthcare providers, as patients often need to be treated empirically, at least initially, although delay of appropriate initial antimicrobial therapy is known to increase morbidity significantly and to increase mortality among affected patients. This elevated risk is compounded by the presence of antibiotic-resistant bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), extended-spectrum beta-lactamase-producing Enterobacteriaceae, Escherichia coli and Klebsiella pneumoniae. Prompt initiation of treatment with an appropriate antimicrobial agent that is active against both Gram-positive and Gram-negative organisms is prudent for patients with nosocomial infections. As the continued usefulness of vancomycin comes into question, the number of alternative agents that provide efficacy equal to that of vancomycin remains limited. The development of novel and effective alternative agents, such as tigecycline, is therefore important.

Pharmacokinetics and pharmacodynamics of cefpirome in subcutaneous adipose tissue of septic patients

The objective of the present study was to evaluate whether cefpirome, a member of the latest class of broad-spectrum cephalosporins, sufficiently penetrates subcutaneous adipose tissue in septic patients. After the administration of the drug at 2 g, tissue cefpirome concentrations in septic patients (n = 11) and healthy controls (n = 7) were determined over a period of 4 h by means of microdialysis. To assess the antibacterial effect of cefpirome at the target site, the measured pharmacokinetic profiles were simulated in vitro with select strains of Staphylococcus aureus and Pseudomonas aeruginosa. The tissue penetration of cefpirome was significantly impaired in septic patients compared with that in healthy subjects. For subcutaneous adipose tissue, the area under the concentration-versus-time curve values from 0 to 240 min were 13.11 +/- 5.20 g . min/liter in healthy subjects and 6.90 +/- 2.56 g . min/liter in septic patients (P < 0.05). Effective bacterial growth inhibition was observed in all in vitro simulations. This was attributed to the significantly prolonged half-life in tissue (P < 0.05), which kept the tissue cefpirome levels above the MICs for relevant pathogens for extended periods in the septic group. By consideration of a dosing interval of 8 h, the values for the time above MIC (T > MIC) in tissue were greater than 60% for pathogens for which the MIC was Collapse

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MESH Headings

• Adipose Tissue/metabolism
• Adult
• Area Under Curve
• Cephalosporins/adverse effects
• Cephalosporins/pharmacokinetics
• Chromatography, Micellar Electrokinetic Capillary
• Colony Count, Microbial
• Female
• Humans
• Male
• Microbial Sensitivity Tests
• Microdialysis
• Pseudomonas aeruginosa/drug effects
• Sepsis/metabolism
• Staphylococcus aureus/drug effects
• Cefpirome

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Affiliation(s)

Robert Sauermann Department of Clinical Pharmacology, Division of Clinical Pharmacokinetics, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
Georg Delle-Karth
Claudia Marsik
Ilka Steiner
Markus Zeitlinger
Bernhard X Mayer-Helm
Apostolos Georgopoulos
Markus Müller
Christian Joukhadar

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A pragmatic approach to identify extended-spectrum beta-lactamase-producing Klebsiella pneumoniae in Taiwan: in vitro activity of newer and established antimicrobial agents

The activities of 17 antimicrobials were evaluated against 211 clinical extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae isolates from Taiwan. A pragmatic approach by sequential Etest (AB BIODISK, Solna, Sweden) ESBL screen (narrow MIC range) and/or the usual Etest method (broad MIC range) was used. Among 131 isolates with a ceftazidime MIC of > 8 microg/ml, 125 (95.4%) had a reduction of > or =3 log2 dilution steps for ceftazidime (positive test). Among 83 isolates with a ceftriaxone MIC of > 8 microg/ml and ceftazidime MIC at < or =8 microg/ml, 81 (97.5%) had a reduction of > or =3 three log2 dilution steps for ceftriaxone. Among the remaining eight isolates with nondeterminable results, additional Etest MIC method results revealed five ESBL-positive and two ESBL-negative (putative AmpC) determinations. This approach offered a cost-effective strategy to screen for ESBL among large number of isolates. The carbapenems (meropenem and imipenem) were the most active compounds (100% susceptibility) followed by newer fluoroquinolones (levofloxacin, gemifloxacin and gatifloxacin) at approximately 80% susceptible. Co-resistance to gentamicin was 96%, tobramycin 96%, and amikacin 62%. In conclusion, ESBL-producing strains of K. pneumoniae, also resistant to cefepime and aminoglycosides, are now widespread in Taiwan. The carbapenems and newer fluoroquinolones remain quite active against these ESBL strains recognized by this novel diagnostic approach.