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The emergence of resistance and the therapy of septicaemia
Abstract:
There were 658 positive blood cultures in St. Thomas' Hospital during 1982-1984, from which 301 Enterobacteriaceae were isolated. Most were of species that do not usually produce inducible class I beta-lactamases but 39 of the isolates were of species that do. Many of these strains were resistant to the older cephalosporins but resistance to cefuroxime was uncommon and resistance to ceftazidime or cefotaxime was confined to five isolates of Enterobacter cloacae (four of which were from patients who had been previously treated with beta-lactams). In only two cases did initially cefuroxime-sensitive strains unambiguously develop resistance during treatment (one strain each of Enterobacter aerogenes and Citrobacter freundii--both treated with amoxycillin).
Insights
Enterobacteriaceae resistance to newer cephalosporins like cefuroxime, ceftazidime, and cefotaxime was uncommon in this 1982-1984 study. Resistance was mainly seen in Enterobacter cloacae, often in patients with prior beta-lactam exposure.
Area of Science:
- Microbiology
- Infectious Diseases
- Pharmacology
Background:
- Enterobacteriaceae are a significant cause of hospital-acquired infections.
- Beta-lactam antibiotics, including cephalosporins, are crucial for treating these infections.
- The emergence of beta-lactamase enzymes can confer resistance to these drugs.
Purpose of the Study:
- To investigate the prevalence and patterns of beta-lactamase-mediated resistance in Enterobacteriaceae isolated from blood cultures.
- To assess the susceptibility of these isolates to older and newer cephalosporins, including cefuroxime, ceftazidime, and cefotaxime.
Main Methods:
- Retrospective analysis of positive blood culture isolates from St. Thomas' Hospital between 1982 and 1984.
- Identification of Enterobacteriaceae species and assessment of their resistance profiles to various cephalosporins.
- Correlation of resistance patterns with prior antibiotic treatment and specific bacterial species.
Main Results:
- Out of 658 positive blood cultures, 301 Enterobacteriaceae were isolated.
- 39 isolates belonged to species known to produce inducible class I beta-lactamases.
- Resistance to cefuroxime was uncommon; resistance to ceftazidime or cefotaxime was limited to five Enterobacter cloacae isolates, mostly in previously treated patients.
- Two cases showed unambiguous development of cefuroxime resistance during treatment.
Conclusions:
- Newer cephalosporins like cefuroxime, ceftazidime, and cefotaxime demonstrated good activity against most Enterobacteriaceae during this period.
- Enterobacter cloacae exhibited higher resistance rates, particularly in patients with prior beta-lactam exposure.
- Inducible beta-lactamase production remains a concern, necessitating careful monitoring of antibiotic resistance trends.