Interactions Among Subinhibitory Antibiotics, Aerobic Gram-negative Rods, and Human Polymorphonuclear Neutrophils

Mandell, Lionel A.; Afnan, Mohamed

doi:10.1007/978-3-642-73653-7_19

Cited by 2 publications

(7 citation statements)

References 12 publications

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“…This is, in fact, what we found with the piperacillin experiments, and it paralleled our previously reported ticarcillin results (15). However, with imipenem and ciprofloxacin, no such effects were demonstrable.…”

Section: Methodssupporting

confidence: 92%

“…This was true for piperacillin-, imipenem-, and ciprofloxacin-pretreated organisms, as described in this article, as well as for ticarcillin-and tobramycin-treated organisms (15). We then tried to determine if the susceptibility to PMN killing could be demonstrated even when phagosome formation was blocked.…”

Section: Methodsmentioning

confidence: 94%

“…The method of radioactive labeling and the techniques used for measurement of phagocytosis and killing were those of Verbrugh and Verhoef et al (25,26) with the modifications that we previously described (15). A serum-resistant strain of E. coli 018:K1:H7 was used, and serum resistance was tested before and after exposure of the E. coli to sub-MICs of the test antibiotics (24).…”

Section: Methodsmentioning

confidence: 99%

“…When no opsonin was present, killing dropped off, but no significant differences were noted between control and antibiotic-pretreated groups. When bacteria were op- us showed that, in fact, tobramycin pretreatment of E. coli also resulted in enhanced killing of the test organisms (15).…”

Section: Methodsmentioning

confidence: 99%

“…In previous studies, we reported the interactions among sub-MICs of ticarcillin and tobramycin, Escherichia coli, and human PMNs (15). Pretreatment of E. coli with a sub-MIC of either of these drugs resulted in increased killing of the bacteria by PMNs that was independent of ingestion of the organisms by PMNs.…”

mentioning

confidence: 94%

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Mechanisms of interaction among subinhibitory concentrations of antibiotics, human polymorphonuclear neutrophils, and gram-negative bacilli

Mandell

Afnan

1991

Antimicrob Agents Chemother

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Our hypothesis was that pretreatment of bacteria with subinhibitory concentrations (sub-MICs) of antibiotics enhances the susceptibility of the organisms to killing by human polymorphonuclear neutrophils (PMNs). Our purpose was to study a variety of drugs with different mechanisms of action and to determine whether the mechanism and locus of action altered the sub-MIC effect. The following outcome measures were used: ingestion and killing of bacteria by PMNs, bacterial killing in the absence of phagosome formation, and binding requirements of the bacteria to PMNs. The antibiotics used were representative of a variety of classes, including beta-lactams (piperacillin and imipenem) and quinolones (ciprofloxacin). Bacterial uptake and killing were measured by using standard techniques, and results were analyzed by using the analysis-of-variance technique and Dunnett's t test. Pretreatment of Escherichia coli with all drugs showed significantly enhanced killing of bacteria by PMNs, which was independent of ingestion by the phagocytes. Even in the absence of phagosome formation, statistically significant killing persisted with piperacillin-pretreated bacteria but not with imipenem-or ciprofioxacin-pretreated organisms. The opsonization experiments showed that contact between bacteria and PMNs was necessary for killing to occur. The sub-MIC effect appears to be independent of the locus or mechanism of action of the antibiotic. It results in enhanced killing by PMNs which is independent of ingestion and also may persist even in the absence of phagosome formation. Killing is dependent upon specific contact between bacteria and an intact phagocyte.

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Section: Methodssupporting

confidence: 92%

Section: Methodsmentioning

confidence: 94%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 94%

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Mechanisms of interaction among subinhibitory concentrations of antibiotics, human polymorphonuclear neutrophils, and gram-negative bacilli

Mandell

Afnan

1991

Antimicrob Agents Chemother

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Exposure Effects of Netilmicin on <i>Enterobacter cloacae </i>Clinical Isolates

Tzouvelekis

Mentis²,

Tzelepi³

et al. 1992

Chemotherapy

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The effects of netilmicin exposure on two aminoglycoside (AMG)-resistant and two AMG-susceptible Enterobacter cloacae isolates were studied. It was found that 1 h incubation of bacterial suspensions with netilmicin at 16 mg/l reduces the amounts of lipopolysaccharides present on the bacterial surface. Also, netilmicin pretreatment increased both the susceptibility to normal human serum and the adhesion to human epithelial cells of all four E. cloacae strains examined.

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Interactions Among Subinhibitory Antibiotics, Aerobic Gram-negative Rods, and Human Polymorphonuclear Neutrophils

Cited by 2 publications

References 12 publications

Mechanisms of interaction among subinhibitory concentrations of antibiotics, human polymorphonuclear neutrophils, and gram-negative bacilli

Mechanisms of interaction among subinhibitory concentrations of antibiotics, human polymorphonuclear neutrophils, and gram-negative bacilli

Exposure Effects of Netilmicin on <i>Enterobacter cloacae </i>Clinical Isolates

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