In vitro evaluation of cefepime and other broad-spectrum beta-lactams for isolates in Malaysia and Singapore medical centers. The Malaysia/Singapore Antimicrobial Resistance Study Group

Adverse Hospital Outcomes Associated With the Choice of Empiric Antibiotics in Klebsiella pneumoniae Pneumonia: A Retrospective Observational Study

Introduction: In Malaysia, Klebsiella pneumoniae ranks high as a cause of adult pneumonia requiring hospitalisation. Patients and Methods: With concern over its rising microbial resistance, we explored the association of empiric antibiotics choices with the hospital outcomes of patients treated for microbial proven K. pneumoniae pneumonia in an urban-based teaching hospital. Results: In 313 eligible cases reviewed retrospectively, hospital mortality and requirement for ventilation were 14.3% and 10.8% respectively. Empiric regimes that had in vitro resistance to at least one empiric antibiotic (n = 90) were associated with higher hospital mortality (23.3% vs. 10.8%, P = 0.004) with risk increased by about two-fold [Odds ratio (OR), 2.5; 95% confidence interval (CI), 1.3 to 4.8]. Regimes (n = 84) other than the commonly recommended “standard” regimes (a β-lactam stable antibiotic with or without a macrolide) were associated with higher ventilation rates (16.7% vs. 8.8%, P = 0.047) with similar increased risk [OR, 2.0; 95% CI, 1.0 to 4.3]. Conclusions: Our findings reiterate the clinical relevance of in vitro microbial resistance in adult K. pneumoniae pneumonia and support empiric regimes that contain β-lactam stable antibiotics. Key words: In vitro resistance, Malaysia

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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Extended-spectrum β-lactamases: implications for the clinical microbiology laboratory, therapy, and infection control

Extended-spectrum beta-lactamase (ESBL) producing gram-negative bacilli are a growing concern in human medicine today. When producing these enzymes, organisms (mostly K. pneumoniae and E. coli) become highly efficient at inactivating the newer third-generation cephaloporins (such as cefotaxime, ceftazidime, and ceftriaxone). In addition, ESBL-producing bacteria are frequently resistant to many classes of non-beta-lactam antibiotics, resulting in difficult-to-treat infections. This review gives an introduction into the topic and is focused on various aspects of ESBLs; it covers the current epidemiology, the problems of ESBL detection and the clinical relevance of infections caused by ESBL-producing organisms. Therapeutic options and potential strategies for dealing with this growing problem are also discussed in this article.

Extended spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae: considerations for diagnosis, prevention and drug treatment

Extended spectrum beta-lactamase (ESBL)-producing organisms pose unique challenges to clinical microbiologists, clinicians, infection control professionals and antibacterial-discovery scientists. ESBLs are enzymes capable of hydrolysing penicillins, broad-spectrum cephalosporins and monobactams, and are generally derived from TEM and SHV-type enzymes. ESBLs are often located on plasmids that are transferable from strain to strain and between bacterial species. Although the prevalence of ESBLs is not known, it is clearly increasing, and in many parts of the world 10-40% of strains of Escherichia coli and Klebsiella pneumoniae express ESBLs. ESBL-producing Enterobacteriaceae have been responsible for numerous outbreaks of infection throughout the world and pose challenging infection control issues. Clinical outcomes data indicate that ESBLs are clinically significant and, when detected, indicate the need for the use of appropriate antibacterial agents. Unfortunately, the laboratory detection of ESBLs can be complex and, at times, misleading. Antibacterial choice is often complicated by multi-resistance. Many ESBL-producing organisms also express AmpC beta-lactamases and may be co-transferred with plasmids mediating aminoglycoside resistance. In addition, there is an increasing association between ESBL production and fluoroquinolone resistance. Although in in vitro tests ESBLs are inhibited by beta-lactamase inhibitors such as clavulanic acid, the activity of beta-lactam/beta-lactamase inhibitor combination agents is influenced by the bacterial inoculum, dose administration regimen and specific type of ESBL present. Currently, carbapenems are regarded as the drugs of choice for treatment of infections caused by ESBL-producing organisms. Unfortunately, use of carbapenems has been associated with the emergence of carbapenem-resistant bacterial species such as Stenotrophomonas sp. or Pseudomonas sp.

Widespread resistance to new antimicrobials in a university hospital before clinical use

The activity of cefpirome, cefepime and piperacillin/tazobactam previously unused in the hospital was evaluated in parallel with five broad-spectrum antibiotics (ceftazidime, ceftriaxone, imipenem, ciprofloxacin and amikacin) currently being used to treat serious infections in the National University Hospital, Singapore. Two hundred and two clinically significant, organisms consecutively isolated during 1998 were included in the study. In vitro efficacy of cefepime, cefpirome and piperacillin/tazobactam was not superior to imipenem, ciprofloxacin and amikacin which are currently used. More than 40% of Enterbacteriaceae were found to be ESBL producers. The incidence of nosocomial organisms resistant to drugs used in serious infections had increased since 1995. Imipenem-resistance occurred in 34.4% of Acinetobacter spp. and 19.2% Pseudomonas aeruginosa. No single agent appeared to be suitable for empirical monotherapy of serious sepsis.