Proceedings of the Sixth International Conference on the Macrolides, Azalides, Streptogramins, Ketolides and Oxazolidinones.

23-25 January, 2002, Bolgna, Italy
Poster # 03.13

Comparative Activity of Lincomycin and Clindamycin Against Staphylococcus aureus Isolated from Hospitalized Patients

VLADIMIR A. KRETCHIKOV, ANDREI V. DEKHNICH, INNA A. EDELSTEIN, ANNA D. NAREZKINA, MAXIM A. PIMKIN

Institute of Antimicrobial Chemotherapy, Smolensk, Russia

The PDF format poster (146 kb)

• Abstract
• Background
• Objective
• Methods
• Results
• Conclusion

ABSTRACT

Background: There are two lincosamyde antibiotics currently available in Russia - lincomycin and clindamycin. In vitro activity of clindamycin against staphylococci has been evaluated extensively, but there are a little data available on lincomycin.

Objective: To compare the in vitro activity of clindamycin and lincomycin against S.aureus isolated from hospitalized patients.

Methods: A total of 555 clinical isolates of S.aureus obtained from hospitalised patients from 16 centres in different regions of Russia has been studied. Susceptibility to clindamycin and lincomycin was determined by agar dilution method in accordance with the NCCLS recommendations. Interpretation of susceptibility testing results for clindamycin was done according to the NCCLS guidelines (no recommendations are available for lincomycin). The S.aureus ATCC 29213 was used as a control strain.

Results: MIC₅₀, MIC₉₀ and MICs ranges for tested antimicrobials are shown in the table. Clindamycin was significantly more active than lincomycin against tested strains. Its MIC in general was 4 dilutions lower than MIC of lincomycin. Moreover, 14 of clindamycin susceptible strains (MIC<0.5 mg/l) have MIC for lincomycin >128 mg/l.

Conclusion: Lincomycin has a significantly lower in vitro activity than clindamycin against S.aureus, so, lincomycin should not be used for treatment of staphylococcal infections.

BACKGROUND

Among two lincosamydes available in Russia the in vitro activity of clindamycin against staphylococci has been evaluated, but, unfortunately, there are a little data available on lincomycin. We performed this study to obtain more data about lincomycin activity against S.aureus isolated in Russian hospitals and to compare it with clindamycin activity.

OBJECTIVE

To compare the in vitro activity of clindamycin and lincomycin against S.aureus isolated from hospitalized patients.

METHODS

Strains: A total of 555 clinical strains of S.aureus isolated in 2000-2001 from patients hospitalized in 16 medical institutions in different parts of Russia (see figure 1): 3 in Central region (Moscow, Ryazan, Smolensk), 2 in North-Western region (St.-Petersburg), 3 in Southern region (Krasnodar, Stavropol), 2 in Volga region (N. Novgorod, Kazan), 3 in Ural region (Ekaterinburg, Ufa), 3 in Siberia (Krasnoyarsk, Novosibirsk, Tomsk) were included in the study.

All strains were shipped to a reference laboratory of Institute of Antimicrobial Chemotherapy (Smolesnk, Russia) and re-identified there by standard biochemical methods and stored at 70^o C in glycerol broth.

Susceptibility testing: Minimal inhibitory concentrations (MICs) to clindamycin and lincomycin were determined by agar dilution method on Mueller-Hinton II agar (BBL, USA). Interpretation of susceptibility testing results for clindamycin was done according to the NCCLS guidelines (2001), but no recommendations are available for lincomycin.

Quality control: S.aureus ATCC 29213 was used as a control strain.

Figure 1. Centers participated in the study

RESULTS

MIC₅₀, MIC₉₀ and MICs ranges for tested antimicrobials are shown in the table. MICs distribution are presented on figures 2 and 3. Clindamycin found to be significantly more active than lincomycin against tested strains. Its MIC in general was 4 dilutions lower than MIC of lincomycin. Moreover, 14 of clindamycin susceptible strains (MIC<0.5 mg/l) have MIC for lincomycin >128 mg/l.

Table. In vitro activity clindamycin and lincomycin against S.aureus

Figure 2. MIC distributions for clindamycin

Figure 3. MIC distributions for lincomycin

CONCLUSIONS

• Lincomycin has a significantly lower in vitro activity than clindamycin against nosocomial S.aureus.
• Lincomycin activity against S.aureus is doubtful, so the further clinical investigations are needed.