Ampicillin a Broad-Spectrum Penicillin

Trafford, J. A. P.; Maclaren, D. M.; Lillicrap, D.A.; Barnes, R. D.; Houston, John; Knox, Robert

doi:10.1016/s0140-6736(62)92030-5

Cited by 50 publications

(22 citation statements)

References 9 publications

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“…Similar findings with ampicillin were reported by Rolinson & Stevens (1961) who showed that certain Gram-negative bacteria were capable of destroying the antibiotic, but that others were capable of growing in high concentrations of it; these results have been confirmed by other workers (Stewart, Coles, Nixon & Holt, 1961;Trafford et al 1962 ;Ayliffe, 1963). Thus, with ampicillin, as with benzylpenicillin, penicillinase appeared to occupy an indeterminate role in the resistance of Gram-negative bacteria towards penicillins.…”

Section: Introductionsupporting

confidence: 85%

The Nature of the Insensitivity of Gram-Negative Bacteria towards Penicillins

Sutherland¹

1964

Journal of General Microbiology

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SUMMARYThe insensitivity of Gram-negative bacteria towards different penicillins has been correlated with the inactivation of these compounds by the penicillinases produced by these bacteria. Penicillins such as phenethicillin, propicillin, methicillin, and cloxacillin were relatively inactive against Gram-negative bacteria, but resistance was not accompanied by inactivation of these compounds. With ampicillin and benzylpenicillin, however, bacterial resistance was associated with destruction of the penicillins. Ampicillin was more stable to the penicillinases produced by certain Gram-negative bacteria than was benzylpenicillin and was correspondingly more active against these organisms. Gram-negative bacteria which produced little or no penicillinase were two to four times more sensitive to ampicillin than to benzylpenicillin, but ampicillin was a t least ten times more active than benzylpenicillin against several penicillinaseproducing coliform organisms. All strains of bacteria which were resistant to both ampicillin and benzylpenicillin were capable of inactivating both compounds, but the insensitivity of these bacteria was not necessarily due solely to penicillinase production. Strains of Pseudomonas aeruginosa and certain strains of Escherichia coli and Protew mirabilis were able to grow in high concentrations of these antibiotics, whereas with the strains of Aerobacter aerogernes, Protew morgartii and Proteus vulgaris examined, the resistance appeared to be due solely to inactivation of the penicillins.

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Section: Introductionsupporting

confidence: 85%

The Nature of the Insensitivity of Gram-Negative Bacteria towards Penicillins

Sutherland¹

1964

Journal of General Microbiology

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“…Ampicillin, a 'broad spectrum' semisynthetic penicillin, has been shown to be active (Rolinson & Stevens, 1961) against several species of Gram-negative bacteria as well as against Gram-positive organisms; however, it has not proved to be effective, either in clinical or in laboratory studies, against some species of Gramnegative bacteria, notably KlebsieZZa aerogernes and certain strains of Proteus and Pseudomonas (Trafford et al 1962; Barber & Waterworth, 1964). Such organisms have become relatively more important as hospital pathogens (Anderson et al 1964) since the introduction of the ' penicillinase-stable ' penicillins, methicillin and cloxacillin, which has temporarily checked the penicillinase-producing Staphy Zococcus aureus.…”

Section: Introductionmentioning

confidence: 99%

Modes of Resistance to Benzylpenicillin and Ampicillin in Twelve Klebsiella Strains

Hamilton‐Miller

1965

Journal of General Microbiology

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SUMMARYTube sensitivity tests show that, of twelve penicillins, ampicillin, benzylpenicillin and 6-aminopenicillanic acid were the most active when tested against medium-sized inocula ( 106 organisms) of twelve strains of penicillinase-producing Klebsiella ( 11 Klebsiella mrogems and 1 R. oxaenae), which had been isolated from clinical material and were resistant to both ampicillin and tetracycline. An inoculum size effect was consistently noted when ampicillin and benzylpenicillin were tested against different inocula ; the effect was significantly greater with ampicillin. The following parameters were measured for the strains, using both benzylpenicillin and ampicillin : magnitude of the inoculum size effect; inherent sensitivity (sensitivity of a small inoculum) ; rate of penicillin destruction; ability of penicillins to pass bacterial permeability barriers. From considerations of the relationships between these values, it has been concluded that penicillinase is primarily responsible for the observed resistance of only two of the twelve strains ; although penicillinase and the lack of ability of penicillins to obtain free access into the bacterial cells add to the over-all penicillin resistance of the other ten strains, the primary reason for their penicillin resistance is neither their possession of penicillinase nor their permeability barrier : such resistance presumably reflects an innate lack of sensitivity of the cell wall synthesizing complex to inhibition by penicillins.

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“…

Ampicillin is already established as a broad spectrum semisyn thetic penicillin of clinical usefulness (Stewart et al 1961, Robinson and Stevens 1961, Brown and Acred 1961, Pendower and Stevens 1962, Brumfitt et al 1962, T rafford et al 1962, Bunn et al 1962, Naumann 1962. Although clinical experience is still limited, ampi cillin can claim a permanent position among broad spectrum anti biotics with the big advantage that it is deprived of toxicity.

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confidence: 99%