Occurrence of clindamycin-resistant anaerobic bacteria isolated from cultures taken following clindamycin therapy

Abstract

MICs of clindamycin were determined by the agar dilution method against anaerobic organisms isolated from endometrial cultures in women with pelvic soft tissue infections. Cultures were obtained from 100 women both before and after clindamycin therapy, from 107 women before therapy with clindamycin or another antimicrobial agent or after treatment with an antimicrobial agent other than clindamycin, and from 9 women 1 to 9 weeks after they were discharged from the hospital following clindamycin therapy. Only 5 (0.7%) of 685 isolates tested from women who had not received cfindamycin therapy were resistant to clindamycin. From the 100 cultures taken immediately after clindamycin therapy, 57 anaerobic bacteria were isolated from 28 cultures. Of the 40 anaerobic organisms for which MICs of clindamycin were determined, 25 (62.51%) were resistant to clindamycin (MIC 2 8 ,ug/ml). The most common organisms isolated after therapy were the anaerobic gram-positive cocci (of which 32 isolates were discovered); of 28 coccal isolates tested, 64% were clindamycin resistant. Four of seven (57%) of the Bacteroides isolates tested, one unidentified gram-positive nonsporing rod, one unidentified gram-negative coccus, and one Mobiluncus sp. were also clindamycin resistant. Of 18 anaerobic isolates from the nine cultures taken 1 to 9 weeks after hospital discharge, 55% were resistant to clindamycin. The clinical significance of these findings is unknown since all patients recovered without incident and remained well. However, the data suggest that physicians need to be aware that patients with recent exposure to clindamnycin may have clindamycin-resistant anaerobic organisms in a current infection. This may prevent the infection from responding to clindamycin treatment.Clindamycin is one of the most common antimicrobial agents used in the treatment of anaerobic infections and continues to be highly effective in most situations (4, 12). In obstetric and gynecologic practice, clindamycin plus an aminoglycoside is a frequent treatment regimen for pelvic soft tissue infections and in studies of safety and efficacy of new antimicrobials is often used as the standard treatment with which newer treatment regimens are compared (2,7,22). In the studies we have done, we have noticed that whereas the clinical outcomes from the clindamycin regimen have been acceptable, a number of clindamycin-resistant anaerobic bacteria, especially anaerobic gram-positive cocci, were isolated from posttreatment cultures. Whereas some investigators have noted the occurrence of clindamycin-resistant anaerobic bacteria in in vitro studies (3,9,14,18, 21), they have not specified the relationship of this occurrence to clindamycin treatment. Others who have presented results of studies in which clindamycin was used to treat obstetric or gynecologic infections have not reported results of posttreatment cultures or the susceptibilities of organisms from these cultures (2, 6, 23). The purpose of the present study was to review pre-and posttreatment culture results, or...

Microbiologic Response to Treatment of Bacterial Vaginosis with Topical Clindamycin or Metronidazole

“…The emergence of clindamycin resistance following treatment is not a novel finding. In 1986, Ohm-Smith et al reported on the emergence of clindamycin-resistant anaerobic bacteria from the endometria of women with pelvic soft tissue infections (23). As in the present study, they found no correlation between antibiotic resistance and clinical response to therapy.…”

Gram-Positive Anaerobic Cocci

“…Antibiotic susceptibility patterns of GPAC a Smith et al(206) described selection of clindamycin-resistant anaerobes, particularly GPAC, following clindamycin therapy for pelvic soft tissue infections. Recently, Reig et al(223) andSanchez et al (230) have described inducible macrolide-lincosamide resistance in several species of GPAC; they recommended that erythromycin susceptibility be assessed before individual isolates are reported as susceptible to clindamycin.…”

Resistance of Peptostreptococcus spp. to macrolides and lincosamides: inducible and constitutive phenotypes

“…For 14% of the Peptococcus strains studied by Sutter and Finegold (13), which were isolated from 1972 to 1975 and that would now be classified as Peptostreptococcus strains (4), the clindamycin MIC was >64 ,ug/ml. On the other hand, the selection of clindamycin-resistant Peptostreptococcus strains (up to 64% of the isolates) in the course of clindamycin therapy has been reported (11). Most clinicians were unaware of these data, and therefore, these antibiotics, particularly clindamycin, continue to distance of 10 to 15 mm on plates inoculated with a swab from a bacterial inoculum that was prepared to achieve a turbidity equal to that of no.…”