Qualitative Study of the Paradoxical Zone Phenomenon of Penicillins against 17 Bacterial Species of Clinical Importance

Yourassowsky, E; Linden, M.P. Vander; Lismont, M.J.; Schoutens, E

doi:10.1159/000237766

Cited by 16 publications

(7 citation statements)

References 4 publications

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“…In a previous study using a triple-layer method and ampicillin neutralization by a beta-lactamase, we found a paradoxical effect for 10 of 10 S. faecalis strains (11).…”

Section: Resultsmentioning

confidence: 65%

Rate of bactericidal activity for Streptococcus faecalis of a new quinolone, CI-934, compared with that of amoxicillin

Yourassowsky¹,

Linden²,

Lismont³

et al. 1986

Antimicrob Agents Chemother

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The rate of bactericidal activity of a new quinolone, CI-934, was compared with that of amoxicillin for 20 strains of Streptococcus faecalis. At 10 and 100 ,ug/ml, the bactericidal activity of CI-934 was more rapid at 6 h than that of amoxicillin. A paradoxical effect (a killing rate higher at 1 Fg/ml than at 100 ,Ig/ml at 6 h) was observed for 19 of the 20 strains with amoxicihlin and for 1 of the 20 strains with containing 30 ml of Iso-Sensitest agar medium was inoculated (before and after dilution, 1/10 and 1/100, respectively) with 0.05 ml of the culture which was distributed on the agar surface by the spiral inoculator system (Spiral System Instruments, Inc., Bethesda, Md.) (6, 10). In this system, a variable cam-activated syringe dispenses the culture from the center to the edge of the plate in a logarithmically decreasing quantity in the form of an Archimedes spiral. The Spiral 500 laser colony counter and the Casba 800 microprocessor (Spiral System Instruments, Inc.) were used for the CFU count. Antibiotic carry-over could be detected by the absence of colonies in the center of the petri dishes. RESULTSThe killing curves (mean CFU ± the standard deviation) for 20 strains of S. faecalis exposed to 1, 10, and 100 ,ug of CI-934 or amoxicillin per ml are shown in Fig. 1.With CI-934, the bactericidal activity was more rapid as the concentration was increased, except for 1 of the 20 strains. For this strain, the killing was more rapid with 1 ,ug/ml than with 10 and 100 ,ug/ml.With amoxicillin, a paradoxical effect (manifested by 1 log10 CFU/ml or more) was observed for 19 of the 20 strains. At 6 h, there was a significant difference (Mann-Whitney test) between the CFU per milliliter of S. faecalis tested with 1 and 10 ,ug of amoxicillin per ml (P < 0.00003) or with 1 and 100 jig/ml (P < 0.00003).Overall comparison of these two antimicrobial agents shows a more rapid killing rate at 6 h by CI-934 than by amoxicillin at 10 ,ug/ml (P < 0.00003) and 100 ,ug/ml (P < 0.00003). DISCUSSION

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“…In a previous study using a triple-layer method and ampicillin neutralization by a beta-lactamase, we found a paradoxical effect for 10 of 10 S. faecalis strains (11).…”

Section: Resultsmentioning

confidence: 65%

Rate of bactericidal activity for Streptococcus faecalis of a new quinolone, CI-934, compared with that of amoxicillin

Yourassowsky¹,

Linden²,

Lismont³

et al. 1986

Antimicrob Agents Chemother

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“…The effect has been observed primarily for cell wall-active agents against a variety of microorganisms, with the effect being observed inconsistently by the broth dilution methodology (1,27). As far as we can tell, the paradoxical effect was not observed for H. influenzae prior to the elegant study by Yourassowsky and associates (41). By using a unique tripleagar-layer disk diffusion method in which the area of the antimicrobial gradient zone around the disk was monitored by optical-galvanometric densitometry for quantitative growth after inactivation of ampicillin by P-lactamase, a variety of gram-positive and gram-negative bacteria were studied for the presence of the paradoxical effect.…”

Section: Discussionmentioning

confidence: 92%

Ampicillin killing curve patterns for ampicillin-susceptible nontypeable Haemophilus influenzae strains by the agar dilution plate count method

Woolfrey

Enright

1990

Antimicrob Agents Chemother

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Ampicillin killing curve patterns for 20 strains of ampicillin-susceptible nontypeable Haemophilus influenzae were determined by the agar dilution plate count method. The paradoxical effect was detected in the 24-h killing curve patterns for each strain. For the biphasic effect, minimum survivor percentages (maximum killing) occurred over a narrow range of ampicillin concentrations immediately above the MIC, with survivor percentages then rising rapidly to peak at --loglo-unit increment higher. The 24-h minimum survivor percentages for the 20 strains ranged from -0.01% (rapid killing) to >10% (slow killing). In comparison with the previous results for typeable strains, the present findings suggest that nontypeable stains are, on average, killed much more slowly. Based on the initial 24-h killing curve patterns for the 20 strains, 4 strains were selected as putative representatives of the range of bactericidal responses encountered. These strains were then studied to examine the reproducibility of the 24-h patterns and to determine sequential killing curves. These patterns were found to be reproducible and served to characterize the relative killing responses of the strains. In the sequential studies of three of the four strains, tiny colonies having the gross and microscopic characteristics of L-forms were found to be present on the agar dilution plate count plates prior to the application of penicillinase at 48 and 72 h. Such colonies reverted to vegetative forms within 24 to 48 h after application of penicillinase to the panels. Of particular interest was the observation that the paradoxical effect was manifested both by the L-form colonies and by the reverted vegetative colonies. The late development of L-forms was observed for both rapidly and slowly killed strains.In a previous study (35) we described ampicillin killing curve patterns for type b Haemophilus influenzae strains as determined by the agar dilution plate count (ADPC) method. Killing curve patterns were found to be strain dependent and ranged from strains that were killed slowly to others that were killed rapidly. The paradoxical effect (7) was demonstrated at some time during the killing sequence for each strain studied. We present here a similar study of ampicillin killing curve patterns for ampicillin-susceptible nontypeable H. influenzae strains. MATERIALS AND METHODSStudy design. Twenty ampicillin-susceptible nontypeable H. influenzae strains were studied. On retrieval from stock culture, each strain was confirmed to by nontypeable H. influenzae and ampicillin susceptible by standard microbiological methods. Several 24-h killing curve patterns were then determined by the ADPC method for each strain (35). On the basis of the 24-h patterns, several putative rapidly to slowly killed strains were studied further to determine the reproducibility of the 24-h patterns and to determine patterns of sequential killing after various times of ampicillin action.H. influenzae strains. Of the 20 ampicillin-susceptible nontypeable H. influenzae isolates stu...

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“…Later, they could also demonstrate that when 200 mg/kg of penicillin was given to mice infected with group B streptococci, a slower killing was achieved than with 3 mg/kg [12]. Thirty years later, Yourassowsky et al [5], using the so-called triple layer technique, could demonstrate a 'par adoxical zone' phenomenon in S. aureus, Streptococcus faecalis and group B strep tococci exposed to penicillin and ampicillin. A paradoxical zone phenomenon was also found with Hemophilus influenzae and Proteus sp., but not with Escherichia coli.…”

Section: Discussionmentioning

confidence: 99%

Paradoxical Effect of Cloxacillin and Benzylpenicillin against Clinical Isolates of <i>Staphylococcus aureus</i>

Odenholt

Holm²,

Cars³

1989

Chemotherapy

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The occurrence of a paradoxical effect of cloxacillin and benzylpenicillin in 7 strains of Staphylococcus aureus was studied with time killing curves in vitro. The isolates were exposed to 1,2, 10 and 100 x MIC of the antibiotics. A paradoxical effect was found in 5/7 strains with cloxacillin and in 4/7 with benzylpenicillin. All strains were killed faster with 2 x MIC than with 100 x MIC. All strains that showed a paradoxical effect with cloxacillin did so already at 10 x MIC. For benzylpenicillin the effect occurred at 10 x MIC for 2 strains and at 100 x MIC for 2. A single MBC/MIC ratio will not reveal the paradoxical effect.

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Qualitative Study of the Paradoxical Zone Phenomenon of Penicillins against 17 Bacterial Species of Clinical Importance

Cited by 16 publications

References 4 publications

Rate of bactericidal activity for Streptococcus faecalis of a new quinolone, CI-934, compared with that of amoxicillin

Rate of bactericidal activity for Streptococcus faecalis of a new quinolone, CI-934, compared with that of amoxicillin

Ampicillin killing curve patterns for ampicillin-susceptible nontypeable Haemophilus influenzae strains by the agar dilution plate count method

Paradoxical Effect of Cloxacillin and Benzylpenicillin against Clinical Isolates of <i>Staphylococcus aureus</i>

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