Antimicrobial sensitivity of Haemophilus influenzae isolates from bacterial conjunctivitis - Poster abstract

OBJECTIVE: To review retrospectively the serotypes and antimicrobial sensitivity of Haemopilus influenzae isolates from bacterial conjunctivitis. DESIGN AND METHODS: Laboratory records over a 9 month period were reviewed. Data on antimicrobial sensitivity (obtained) by the NCCLS disk diffusion method) and á-lactamase production, and typing results, were analysed. RESULTS: 34 isolates were recovered, of which 31 were typed. Most isolates were recovered from children under one year of age. Seventy-one percent were un-encapsulated and bio-types I and IV were most common. H influenzae type b was recovered only once. á=lactamase was produced by 45 percent isolates (14/31) while one was ampicillin-resistant but did not produce á-lactamase. All isolates were sensitive to chloramphenicol and 60 percent were co-trimoazole sensitive. CONCLUSIONS: H influenzae is commonly isolated from bacterial conjunctivitis in Barbadians, and the majority of isolates are from infants and are non-encapsualted. However, there is a high prevalence of á-lactamase production, which may serve as a reservoir for transfer to more invasive encapsulated strains within the oropharyngeal flora.(AU)

Considerations for implementing an antibiotic policy in hospital practice

An antibiotic policy should aim for the safe, effective and economical use of antimicrobial drugs, and to prevent their indiscriminate use and development of resistant bacterial strains. The term 'antibiotic' is used as a general term for all antimicrobial drugs. Antibiotics prescriptions should be based on clinical evidence of bacterial infection, preferably substantiated by appropriate laboratory culture and sensitivity tests. Viral infections are not an indication for antibiotic prescriptions. Patient factors to be considered for choice and dose of an antibiotic are age, pregnancy, lactation, renal and hepatic impairment. Immunodeficient patients should receive only bactericidal drugs. Severity of infection determines the route of administration. Duration of therapy should not exceed five days, unless specifically prescribed by the physician. An antibiotic should, if started as an empirical therapy not be changed before a minimum of three days trial. Prescriptions of drugs such as aztreonam, imipenem, vancomycin, piperacillin and amphotericin are to be restricted due to cost and toxicity and should be reviewed by the microbiologist (AU)

Novel á-lactamases and developing resistance to á-lactams - abstract

The last decade has seen increasing resistance against á-lactam antibiotics, old and new. The rapid evolution of resistance has limited the effective use of even the newest compounds. This resistance is caused mainly by á-lactamases. Most of these enzymes are carried on plasmids or transposons, ensuring wider distribution of resistance among different groups of bacteria, in addition to global spread of resistance. The enzymes found in Escherichia coli and Klebsiella species are now found in community-acquired as well as in hospital-acquired Gram-negative organisms such as Haemophilus, Neisseria, Salmonella and other Enterobacteriaceae. New á-lactamases have arisen by mutation of the older, well-known á-lactamases such as TEM-1 or SHV-1. These mutations result in enzymes which have enhanced affinity for, as well as having the capacity of inactivating, most á-lactam compounds, including the third-generation cephalosporins. The use of á-lactam antibiotics has also contributed to resistance in various ways, namely, through the selection of resistant mutants and through their ability to induce hyperproduction of á-lactamases. Although resistance due to the latter can be reversed, the solution to the ever-increasing prevalence of resistance should be through rational and appropriate use of antibiotics (AU)