Vol. 14, No. 2
ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, Aug. 1978, p. 274-276
0066-4804/78/0014-0274$02.00/0 Copyright © 1978 American Society for Microbiology
Printed in U.S.A.
In Vitro Activity of Rosamicin and Erythromycin Against a Group of Nonfermenting Gram-Negative Bacilli JOSEPH R. DIPERSIO* AND THEODORE L. KRAFCZYK Department of Laboratory Medicine, The Christ Hospital, Cincinnati, Ohio 45219 Received for publication 21 April 1978
The in vitro inhibitory activity of rosamicin and erythromycin against 283 strains of nonfermenting, gram-negative bacilli was determined by using a broth dilution procedure. Rosamicin demonstrated greater activity than erythromycin against most strains tested. A number of species demonstrated significantly lower minimum inhibitory concentrations to rosamicin and would fall within the therapeutic range of the drug based on current pharmacological data.
Rosamicin, a new macrolide antibiotic produced by Micromonospora rosaria, has been reported to be active against a variety of aerobic and facultative bacteria (2, 4, 8, 9). Evidence also indicates activity against many anaerobic species, including Bacteroides fragilis (5-7). In many reports the activity of rosamicin was found to be greater than that of erythromycin. The present study was undertaken to compare the in vitro activity of rosamicin with that of erythromycin against a large group of nonfermenting, gram-negative bacilli. The following strains of bacteria isolated from clinical specimens were used in the study: 21 Pseudomonas aeruginosa, 15 P. maltophilia, 15 P. cepacia, 15 P. stutzeri, 16 P. putrefaciens, 16 P. putida, 15 P. fluorescens, 10 P. alcaligenes, 12 P. vesictuclaris, 12 P. acidovorans, 4 P. pseudoalcaligenes, 2 P. diminuta, 1 P. testosteroni, 20 Acinetobacter Iwoffi, 6 Alcaligenes faecalis, 13 A. odorans, 4 A. denitrificans, 14 Xanthomonas, 13 Moraxella nonliquefaciens, 11 Bordetella bronchicanis, 15 Achromobacter xylosoxidans, 16 Flavobacterium group II B, 6 VE2 group, and 11 VE-1 group. Standard reference powders of rosamicin and erythromycin were provided by Schering Corp., Bloomfield, N.J., and Eli Lilly and Co., Indianapolis, Ind., respectively. The minimum inhibitory concentration (MIC) of each antibiotic was determined by using serial twofold microdilutions in Mueller-Hinton broth (Difco Laboratories, Detroit, Mich.). Stock solutions of rosamicin and erythromycin were prepared and quality controlled by the tube dilution procedure by using organisms with known MICs. These strains included Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, and P. aeruginosa ATCC 27853. Dilutions of antibiotics in broth were dispensed in 100-,ul volumes into plastic microdilution trays by using an MIC-
2000 dispenser (Cooke Laboratory Products, Alexandria, Va.) and frozen at -70°C until use. Trays were quality controlled by using reference strains after initial preparation and again each time a group of plates was used. Reference MICs did not vary more than ±1 dilution interval during the study. Organisms to be tested were grown in Trypticase soy broth, standardized turbidimnetrically, by using a Spectronic 88 (Bausch & Lomb, Inc., Rochester, N.Y.) at 640 nm and diluted to a final concentration in Mueller-Hinton broth. Trays were inoculated by using an MIC-2000 inoculator (Cooke Laboratory Products, Alexandria, Va.) to give a final concentration of approximately 105 colony-forming units per ml and incubated for 18 to 24 h at 35°C. Quality control of inoculum size was performed by pour plates. The MIC end point was defined as the microdilution containing the lowest concentration of antibiotic showing no visible growth. The activity of rosamicin and erythromycin against species of Pseudomonas is shown in Table 1. With strains of P. aeruginosa, the activity of the two antibiotics was similar. MICs against all strains tested were >25 ILg/ml. With the majority of other Pseudomonas species, rosamicin was found to be at least fourfold more active than erythromycin. Rosamicin inhibited 70% of P. alcaligenes and 100% of P. putrefaciens at a concentration of 0.78 ,ug/ml, compared with 30 and 44%, respectively, inhibited by erythromycin. Rosamicin was likewise more active against strains of P. vesicularis, P. diminuta, P. acidovorans, and P. stutzeri. The activity of the two antibiotics against a group of miscellaneous, nonfermenting, gramnegative bacilli is shown in Table 2. Rosamicin again was found to be more active than erythromycin against most species tested. Rosamicin was distinctly more active than erythromycin
274
VOL. 14, 1978
NOTES
against Xanthomonas species. All but one strain inhibited by 0.78 ,ug or less of rosamicin per ml, whereas only 29% were inhibited by 0.78 ,ug or less of erythromycin per ml. Rosamicin also demonstrated high activity against strains of A. faecalis, M. nonliquefaciens, and A. Iwoffi. The in vitro results presented in Tables 1 and
275
2 indicate that rosamicin is more active than erythromycin against 24 species of nonfermenting, gram-negative bacilli. Of the 24 species tested, 100% of 14 species were inhibited by concentrations of rosamicin at least 2 dilutions less than erythromycin. Pharmacological data to date have revealed
were
TABLE 1. Comparative activities of rosamicin and erythromycin: MICs against different pseudomonads Cumulative % of strains inhibited at an MIC (,ug/ml) of: Organism (no. tested)
Antibiotic
50.049 0.098 0.195 0.39 P. aeruginosa (21) P. fluorescens (15) P. putida (16) P. cepacia (15)
P. alcaligenes (10)
P. stutzeri (15)
P. pseudoalcaligenes (4) P. maltophilia (15) P. diminuta (2) P. vesicularis (12) P. acidovorans (12)
P. putrefaciens (16)
P. testosteroni (1)
0.78
Rosamicin Erythromycin Rosamicin
Erythromycin Rosamnicin Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin
1.56 3.125 6.25
7
20
47 20
6
10
20
40
7
13 7
80
70 30 40
10
90
67 13
13
50
100
75
83 25
50
6
92 58
19
6 73
20
7
50 100 40 25
80
33
73
12.5
25.0
60 53 13
87 67 19
100 7 100 80
20
27
90
100
100 75 25 93 7
100 75 100 13
100
100
100 25
33
50
50.0 >50.0 52 100 100 100 100 81 100 100 100
100 100
83 88 13 100
92 33
100 92
50
100 44
81
100
100
100
TABLE 2. Comparative activities of rosamicin and erythromycin: MICs against miscellaneous, nonfermenting, gram-negative bacilli Organism (no. tested)
Cumulative % of strains inhibited at an MIC (,ug/ml) of:
Antibiotic
c0.049 0.098 0.195 0.39 0.78 1.56 3.125 6.25 12.5 25.0 50.0 >50.0 Xanthomonas (14)
Rosamicin
VE-1 group (11)
Rosamicin
VE-2 group (6)
A. odorans (13) A. denitrificans (4) A. faecalis (6)
Flavobacterium group II B (16) A. xylosoxidans (15) B. bronchicanis (11) M. nonliquefaciens (13)
Erythromycin
36
64 14
86 21
93 29 73
Erythromycin Rosamicin
67
Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin
36 100 45 83 50
43 91 100 83 15
25
100 50
Rosamicin Rosamicin Rosamicin
Erythromycin
93
50
100 92 75
17
67 33
100 100 100 75 83
50 6
67 19
50
13
87
6 9 9 85 38 30
27 54 50 5
92 69 20
85 75 30
55 92 95 50
64 27
91 55 100
100 64
73 100
100 80
100
100
Erythromycin Erythromycin
71
25
33
Rosamicin
Erythromycin A. Iwoffi (20)
21 7
100
81 56 100
100
100 100 100
100 94
100
13
100
276
NOTES
concentrations in serum after a 250-mg oral dosof rosamicin to be only half those of erythromycin (Informational Material for Investiga-
age
tional Drug Rosamicin, Schering Corp., Bloomfield, N.J., 1976). An upper therapeutic limit for rosamicin after a 250-mg oral dosage may therefore only be approximately 1 ,ug/ml (George Arcieri, Schering Corp., personal communication). Rosamicin, however, has been shown to attain higher levels in urethral and vaginal secretions of dogs and rats (3) as well as human prostatic tissue (1). The drug may have value in the treatment of infections involving the urogenital tract. A recent study has shown rosamicin to be highly active against isolates of Neisseria gonorrhoeae, including penicillinase-producing strains (4). Although rosamicin was consistently more active than erythromycin against most organisms tested in the present study, the MICs against many strains still would not fall below the presently accepted upper limit of clinical susceptibility. The value of rosamicin in the treatment of infections involving nonfermenting, gram-negative bacilli must await fuirther study. This investigation was supported by a grant from the Schering Corp., Bloomfield, N.J. The authors thank Gerald Gilardi for supplying many of the strains tested and Anna Cox for typing the manuscript.
ANTIMICROB. AGENTS CHEMOTHER. LITERATURE CITED 1. Baumueller, A., U. Hoyme, and P. 0. Madsen. 1977. Rosamicin-a new drug for the treatment of bacterial prostatitis. Antimicrob. Agents Chemother. 12:240-242. 2. Crowe, CC., and W. E. Sanders, Jr. 1974. Rosamicin: evaluation in vitro and comparison with erythromycin and lincomycin. Antimicrob. Agents Chemother. 5:272-275. 3. Hoyme, U., A. Baumueller, and P. 0. Madsen. 1977. Rosamicin in urethral and vaginal secretions and tissues in dogs and rats. Antimicrob. Agents Chemother. 12:237-239. 4. Sanders, C. C., and W. E. Sanders. 1977. In vitro activity of rosamicin against Neisseria and Haemophilus, including penicillinase-producing strains. Antimicrob. Agents Chemother. 12:293-294. 5. Santoro, J., D. Kaye, and M. E. Levison. 1976. In vitro activity of josamycin and rosamicin against Bacteroides fragilis compared with clindamycin, erythromycin, and metronidazole. Antimicrob. Agents Chemother. 10:188-190. 6. Shadomy, S., M. Tipple, and L. Paxton. 1976. Josamycin and rosamicin: in vitro comparisons with erythromycin and clindamycin. Antimicrob. Agents Chemother. 10:773-775. 7. Sutter, V. L., and S. M. Finegold. 1976. Rosamicin: in vitro activity against anaerobes and comparison with erythromycin. Antimicrob. Agents Chemother. 9:350-351. 8. Wagman, G. H., J. A. Waitz, J. Marquez, A. Murawski, E. M. Oden, R. T. Testa, and M. J. Weinstein. 1972. A new Micromonospora-produced macrolide antibiotic, rosamicin. J. Antibiot. (Tokyo) 25:641-646. 9. Waitz, J. A., C. G. Drube, E. L. Moss, Jr., and M. J. Weinstein. 1972. Biological studies with rosamicin, a new Micromonospora-produced macrolide antibiotic. J. Antibiot. (Tokyo) 25:647-652.
ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, Aug. 1978, p. 274-276
0066-4804/78/0014-0274$02.00/0 Copyright © 1978 American Society for Microbiology
Printed in U.S.A.
In Vitro Activity of Rosamicin and Erythromycin Against a Group of Nonfermenting Gram-Negative Bacilli JOSEPH R. DIPERSIO* AND THEODORE L. KRAFCZYK Department of Laboratory Medicine, The Christ Hospital, Cincinnati, Ohio 45219 Received for publication 21 April 1978
The in vitro inhibitory activity of rosamicin and erythromycin against 283 strains of nonfermenting, gram-negative bacilli was determined by using a broth dilution procedure. Rosamicin demonstrated greater activity than erythromycin against most strains tested. A number of species demonstrated significantly lower minimum inhibitory concentrations to rosamicin and would fall within the therapeutic range of the drug based on current pharmacological data.
Rosamicin, a new macrolide antibiotic produced by Micromonospora rosaria, has been reported to be active against a variety of aerobic and facultative bacteria (2, 4, 8, 9). Evidence also indicates activity against many anaerobic species, including Bacteroides fragilis (5-7). In many reports the activity of rosamicin was found to be greater than that of erythromycin. The present study was undertaken to compare the in vitro activity of rosamicin with that of erythromycin against a large group of nonfermenting, gram-negative bacilli. The following strains of bacteria isolated from clinical specimens were used in the study: 21 Pseudomonas aeruginosa, 15 P. maltophilia, 15 P. cepacia, 15 P. stutzeri, 16 P. putrefaciens, 16 P. putida, 15 P. fluorescens, 10 P. alcaligenes, 12 P. vesictuclaris, 12 P. acidovorans, 4 P. pseudoalcaligenes, 2 P. diminuta, 1 P. testosteroni, 20 Acinetobacter Iwoffi, 6 Alcaligenes faecalis, 13 A. odorans, 4 A. denitrificans, 14 Xanthomonas, 13 Moraxella nonliquefaciens, 11 Bordetella bronchicanis, 15 Achromobacter xylosoxidans, 16 Flavobacterium group II B, 6 VE2 group, and 11 VE-1 group. Standard reference powders of rosamicin and erythromycin were provided by Schering Corp., Bloomfield, N.J., and Eli Lilly and Co., Indianapolis, Ind., respectively. The minimum inhibitory concentration (MIC) of each antibiotic was determined by using serial twofold microdilutions in Mueller-Hinton broth (Difco Laboratories, Detroit, Mich.). Stock solutions of rosamicin and erythromycin were prepared and quality controlled by the tube dilution procedure by using organisms with known MICs. These strains included Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, and P. aeruginosa ATCC 27853. Dilutions of antibiotics in broth were dispensed in 100-,ul volumes into plastic microdilution trays by using an MIC-
2000 dispenser (Cooke Laboratory Products, Alexandria, Va.) and frozen at -70°C until use. Trays were quality controlled by using reference strains after initial preparation and again each time a group of plates was used. Reference MICs did not vary more than ±1 dilution interval during the study. Organisms to be tested were grown in Trypticase soy broth, standardized turbidimnetrically, by using a Spectronic 88 (Bausch & Lomb, Inc., Rochester, N.Y.) at 640 nm and diluted to a final concentration in Mueller-Hinton broth. Trays were inoculated by using an MIC-2000 inoculator (Cooke Laboratory Products, Alexandria, Va.) to give a final concentration of approximately 105 colony-forming units per ml and incubated for 18 to 24 h at 35°C. Quality control of inoculum size was performed by pour plates. The MIC end point was defined as the microdilution containing the lowest concentration of antibiotic showing no visible growth. The activity of rosamicin and erythromycin against species of Pseudomonas is shown in Table 1. With strains of P. aeruginosa, the activity of the two antibiotics was similar. MICs against all strains tested were >25 ILg/ml. With the majority of other Pseudomonas species, rosamicin was found to be at least fourfold more active than erythromycin. Rosamicin inhibited 70% of P. alcaligenes and 100% of P. putrefaciens at a concentration of 0.78 ,ug/ml, compared with 30 and 44%, respectively, inhibited by erythromycin. Rosamicin was likewise more active against strains of P. vesicularis, P. diminuta, P. acidovorans, and P. stutzeri. The activity of the two antibiotics against a group of miscellaneous, nonfermenting, gramnegative bacilli is shown in Table 2. Rosamicin again was found to be more active than erythromycin against most species tested. Rosamicin was distinctly more active than erythromycin
274
VOL. 14, 1978
NOTES
against Xanthomonas species. All but one strain inhibited by 0.78 ,ug or less of rosamicin per ml, whereas only 29% were inhibited by 0.78 ,ug or less of erythromycin per ml. Rosamicin also demonstrated high activity against strains of A. faecalis, M. nonliquefaciens, and A. Iwoffi. The in vitro results presented in Tables 1 and
275
2 indicate that rosamicin is more active than erythromycin against 24 species of nonfermenting, gram-negative bacilli. Of the 24 species tested, 100% of 14 species were inhibited by concentrations of rosamicin at least 2 dilutions less than erythromycin. Pharmacological data to date have revealed
were
TABLE 1. Comparative activities of rosamicin and erythromycin: MICs against different pseudomonads Cumulative % of strains inhibited at an MIC (,ug/ml) of: Organism (no. tested)
Antibiotic
50.049 0.098 0.195 0.39 P. aeruginosa (21) P. fluorescens (15) P. putida (16) P. cepacia (15)
P. alcaligenes (10)
P. stutzeri (15)
P. pseudoalcaligenes (4) P. maltophilia (15) P. diminuta (2) P. vesicularis (12) P. acidovorans (12)
P. putrefaciens (16)
P. testosteroni (1)
0.78
Rosamicin Erythromycin Rosamicin
Erythromycin Rosamnicin Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin
1.56 3.125 6.25
7
20
47 20
6
10
20
40
7
13 7
80
70 30 40
10
90
67 13
13
50
100
75
83 25
50
6
92 58
19
6 73
20
7
50 100 40 25
80
33
73
12.5
25.0
60 53 13
87 67 19
100 7 100 80
20
27
90
100
100 75 25 93 7
100 75 100 13
100
100
100 25
33
50
50.0 >50.0 52 100 100 100 100 81 100 100 100
100 100
83 88 13 100
92 33
100 92
50
100 44
81
100
100
100
TABLE 2. Comparative activities of rosamicin and erythromycin: MICs against miscellaneous, nonfermenting, gram-negative bacilli Organism (no. tested)
Cumulative % of strains inhibited at an MIC (,ug/ml) of:
Antibiotic
c0.049 0.098 0.195 0.39 0.78 1.56 3.125 6.25 12.5 25.0 50.0 >50.0 Xanthomonas (14)
Rosamicin
VE-1 group (11)
Rosamicin
VE-2 group (6)
A. odorans (13) A. denitrificans (4) A. faecalis (6)
Flavobacterium group II B (16) A. xylosoxidans (15) B. bronchicanis (11) M. nonliquefaciens (13)
Erythromycin
36
64 14
86 21
93 29 73
Erythromycin Rosamicin
67
Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin Rosamicin Erythromycin
36 100 45 83 50
43 91 100 83 15
25
100 50
Rosamicin Rosamicin Rosamicin
Erythromycin
93
50
100 92 75
17
67 33
100 100 100 75 83
50 6
67 19
50
13
87
6 9 9 85 38 30
27 54 50 5
92 69 20
85 75 30
55 92 95 50
64 27
91 55 100
100 64
73 100
100 80
100
100
Erythromycin Erythromycin
71
25
33
Rosamicin
Erythromycin A. Iwoffi (20)
21 7
100
81 56 100
100
100 100 100
100 94
100
13
100
276
NOTES
concentrations in serum after a 250-mg oral dosof rosamicin to be only half those of erythromycin (Informational Material for Investiga-
age
tional Drug Rosamicin, Schering Corp., Bloomfield, N.J., 1976). An upper therapeutic limit for rosamicin after a 250-mg oral dosage may therefore only be approximately 1 ,ug/ml (George Arcieri, Schering Corp., personal communication). Rosamicin, however, has been shown to attain higher levels in urethral and vaginal secretions of dogs and rats (3) as well as human prostatic tissue (1). The drug may have value in the treatment of infections involving the urogenital tract. A recent study has shown rosamicin to be highly active against isolates of Neisseria gonorrhoeae, including penicillinase-producing strains (4). Although rosamicin was consistently more active than erythromycin against most organisms tested in the present study, the MICs against many strains still would not fall below the presently accepted upper limit of clinical susceptibility. The value of rosamicin in the treatment of infections involving nonfermenting, gram-negative bacilli must await fuirther study. This investigation was supported by a grant from the Schering Corp., Bloomfield, N.J. The authors thank Gerald Gilardi for supplying many of the strains tested and Anna Cox for typing the manuscript.
ANTIMICROB. AGENTS CHEMOTHER. LITERATURE CITED 1. Baumueller, A., U. Hoyme, and P. 0. Madsen. 1977. Rosamicin-a new drug for the treatment of bacterial prostatitis. Antimicrob. Agents Chemother. 12:240-242. 2. Crowe, CC., and W. E. Sanders, Jr. 1974. Rosamicin: evaluation in vitro and comparison with erythromycin and lincomycin. Antimicrob. Agents Chemother. 5:272-275. 3. Hoyme, U., A. Baumueller, and P. 0. Madsen. 1977. Rosamicin in urethral and vaginal secretions and tissues in dogs and rats. Antimicrob. Agents Chemother. 12:237-239. 4. Sanders, C. C., and W. E. Sanders. 1977. In vitro activity of rosamicin against Neisseria and Haemophilus, including penicillinase-producing strains. Antimicrob. Agents Chemother. 12:293-294. 5. Santoro, J., D. Kaye, and M. E. Levison. 1976. In vitro activity of josamycin and rosamicin against Bacteroides fragilis compared with clindamycin, erythromycin, and metronidazole. Antimicrob. Agents Chemother. 10:188-190. 6. Shadomy, S., M. Tipple, and L. Paxton. 1976. Josamycin and rosamicin: in vitro comparisons with erythromycin and clindamycin. Antimicrob. Agents Chemother. 10:773-775. 7. Sutter, V. L., and S. M. Finegold. 1976. Rosamicin: in vitro activity against anaerobes and comparison with erythromycin. Antimicrob. Agents Chemother. 9:350-351. 8. Wagman, G. H., J. A. Waitz, J. Marquez, A. Murawski, E. M. Oden, R. T. Testa, and M. J. Weinstein. 1972. A new Micromonospora-produced macrolide antibiotic, rosamicin. J. Antibiot. (Tokyo) 25:641-646. 9. Waitz, J. A., C. G. Drube, E. L. Moss, Jr., and M. J. Weinstein. 1972. Biological studies with rosamicin, a new Micromonospora-produced macrolide antibiotic. J. Antibiot. (Tokyo) 25:647-652.
