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Clostridium difficile is the most common agent of nosocomial bacterial diarrhoea in adults. In 2006, C. difficile outbreaks were described in France with the highly virulent strain PCR-ribotype 027, which is also resistant to moxifloxacin and erythromycin. The aim of this study is to perform a phenotypic and molecular characterization of C. difficile strains isolated in Jean-Verdier-René-Muret hospitals. Thirty three C. difficile toxigenic strains isolated in symptomatic patients from 2001 to 2007 were studied. Toxins A and B detection was performed with an immunoenzymatic method (ICTAB, Meridian). The agar diffusion method was performed for determination of antibiotic susceptibility for metronidazole, vancomycin, erythromycin and moxifloxacin. The E-test was performed for determination of metronidazole, vancomycin and tigecycline MIC. Binary toxin genes cdtA and cdtB were detected by PCR. PCR-ribotyping was performed according to Bidet et al. From 2001 to 2007, all the isolates studied were susceptible to metronidazole, vancomycin and tigecyclin. We observed a significant decrease of susceptibility to moxifloxacin (100% in 2001 versus 28.5% in 2007) and to erythromycin (60% in 2001 versus 14% in 2007). Toxins A/B were detected in all the isolates. Fifteen per cent of the isolates studied produced the binary toxin not correlated with a specific PCR-ribotype. Ribotype 18 was the most prevalent PCR-ribotype detected since 2006. The isolates displaying this PCR-ribotype were resistant to erythromycin and moxifloxacin and were principally isolated in the same ward, suggesting cross infection. This study showed that: (1) over a six-year period, the susceptibility to metronidazole and vancomycin remained stable; (2) different clones of C. difficile circulated during these six years. Recently an epidemic strain resistant to erythromycin and moxifloxacin of ribotype 18 has emerged in the gastroenterology unit where fluoroquinolones are frequently used demonstrating the role of antibiotic selection pressure. The emergence of these isolates could explain the significant decrease of susceptibility to moxifloxacin and erythromycin observed in 2007. However, today, no isolate with a PCR-ribotype 027 was detected.

Aim: The aim of this study was to determine the antimicrobial susceptibilities of Clostridium difficile clinical isolates obtained from symptomatic patients suffering from diarrhoea., Methods: In vitro activities of 22 antimicrobial agents were evaluated against 401 clinical isolates of C. difficile collected from patients hospitalized in a French university hospital (Henri Mondor hospital) between 2001 and 2007. The in vitro antibiotic susceptibility testing was performed using the disc diffusion method according to recommendations of the antibiogram committee of the French society for microbiology., Results: All strains were found to be susceptible to metronidazole and vancomycin but resistant to clindamycin, gentamicin, and colistin. Most of them were susceptible to pristinamycin (97.8%), rifampin (94.8%), and chloramphenicol (97.3%), and variable degrees of resistance were found for erythromycin and spiramycin (72.8%), as well as for tetracycline (85.6%). Note that none of the strain was susceptible to ofloxacin, and that 80.5% of them showed a high-level resistance. For beta-lactams, all strains were resistant to tested cephalosporins, and nine isolates (2.2%) were also resistant to penicillins combined or not to a beta-lactamase inhibitor. Finally, 28 (7%) and 38 (9.5%) of tested strains were categorized intermediate and resistant to imipenem (with a heterogeneous aspect), respectively., Conclusion: All tested strains were found to be susceptible to metronidazole and vancomycin which remain antimicrobial agents for the treatment of infections caused by C. difficile.

Unlabelled: Helicobacter pylori infection is frequent in children. The eradication rate is variable, it is influenced by resistance of the bacteria to the antibiotics used. The aim of this study was to determine the resistance rate of the most commonly used antibiotics among helicobacter pylori (Hp) strains isolated in infected children., Patients and Methods: 60 children (26 males, 34 females), with mean age of 8 years 8 months (3 years and 2 month (2.5-13.5 years) underwent an oesogastroscopy. Forty six of them had helicobacter infection assessed by the presence of Hp on the gastric biopsy and or positivity of urease test. The infected children were treated with three medication; Omeprazole. Clarythromycin, and Amoxicillin. The eradication of Hp was confirmed in 13 patients by the absence of Hp on the gastric biopsy and/or negativation of the urease test;, Results: Culture was positive in 13 infected children susceptibility to anti microbial drugs was done in ten children. Nine children had primary metronidazole resistance, three had both clarythromycin and Metronidazole resistance, three had Clarythromycin primary resistance. No case of Amoxicillin primary resistance was detected. Children eradication was achieved in four children among 13 children. This study shows the difficulty of Hp culture. It confirms the absence of Hp resistance to Amoxicilline. the high level of Hp resistance to Metronidazole and the mild level of Clarythromycin resistance. The authors stress the importance of Antibiotic susceptibility assay in helicobacter pylori infections.

Helicobacter pylori eradication failure generally concerns between 10 and 30% of the patients. When eradication failure occurs, it is necessary a) to try to identify the potential causes, b) to confirm the indication of eradicating H. pylori, and c) to choose a second line therapeutic strategy. Among the factors most frequently associated with failed eradication, are poor compliance, younger age, smoking, and weak gastric inflammatory activity. The major factor of resistance is related to the sensitivity of the bacterial strain to antibiotics used. In France, resistance to clarithromycin is around 10-15% and resistance to metronidazole around 30%. In order to limit development of resistance, it seems preferable to avoid associating clarithromycin and metronidazole in the first line treatment. At best, the first line treatment must follow the official recommendations (PPI-amoxicillin and clarithromycin). In the event of eradication failure, second line treatment calls upon tritherapy which, due to the low rate of resistance to amoxicillin, associates double-dose PPI, amoxicillin and the antibiotic not used during the first line treatment (metronidazole if clarithromycin was initially used and conversely). This approach allows to eradicate between 50 and 80% of the first-line failure patients. In case of further failure a culture with measurement of the strain sensitivity is required. Subsequent treatment associates PPI with the antibiotics to which the strain is sensitive for a longer duration. In some cases, other effective antibiotics, such as rifabutin, might be used in these circumstances.

The available results of triple therapy for the eradication of Helicobacter pylori (H. pylori), as recommended in European countries--i.e. combination of proton pump inhibitor (PPI) and two antibiotics among amoxicillin, clarithromycin, metronidazole for 7 days--lead to rates of failure of about 30%. Several clinical studies have been recently conducted to distinguish factors influencing effectiveness of therapy and to evaluate results of new regimens. Comparative trials have demonstrated the equivalence of omeprazole 20 mg, lansoprazole 30 mg, pantoprazole 40 mg, rabeprazole 20 mg and esomeprazole 20 mg, twice daily in these 7-days triple therapies. Efficacy of treatment is not affected by metronidazole resistance (44% in France) when amoxicillin-clarithromycin-based triple therapy is prescribed. The impact of clarithromycin resistance (14%) is much more important with failure of eradication in all cases treated by clarithromycin-based triple therapy. The eradication rate could be slightly improved by increasing the dose of clarithromycin but with more frequent side effects. To prolong the duration treatment improve also slightly the cure rate with a gain of less than 10%, but with an increasing rate of side effects. To date, the PPI-based triple therapies, as recommended in France, have not to be modified. The treatment of H. pylori infection has to be globally considered, with a first-line treatment leading to eradication in 70% of patients and a second-line treatment needed for the resting 30% of patients.

Aims: To assess the frequency of acquisition of secondary Helicobacter pylori resistant-strains after a first course of antimicrobial treatment., Patients and Methods: A retrospective study was performed during the 1994-2000 period, in 15 girls and eight boys, mean age 10.9 +/- 4.8 years (1.4-17 years), with Helicobacter pylori gastritis (culture and antimicrobial susceptibility) presenting a failure of first course treatment, with during one week a proton pump inhibitor and amoxicillin together with either clarithromycin (n = 14) or metronidazole (n = 9). Two endoscopies were performed, the first at the time of diagnosis and the second after the failure of bacterial eradication demonstrated by a positive 13C urea breath test six weeks after the end of treatment. Antimicrobial susceptibility of all Helicobacter pylori strains was tested after each endoscopy and before starting a second course of the treatment., Results: Comparison of antimicrobial susceptibility before and after the first course of treatment showed that Helicobacter pylori strains were all sensitive to amoxicillin, clarithromycin-resistant in eight children (34.7%) before treatment vs 12 (52.1%) after treatment, p = 0.42, ns, metronidazole-resistant in 13 (56.5%) vs 12 (52.1%), p = 0.80, ns, and both clarithromycin and metronidazole-resistant in four (17.3%) vs seven (30.4%), p = 0.63, ns. Among the 14 children treated by a triple therapy including clarithromycin, three (21.4%) developed a secondary resistance to clarithromycin and in one metronidazole resistance was no more detected. Among the nine children treated with a triple therapy including metronidazole, none developed a secondary resistance to metronidazole and one developed a secondary resistance to clarithromycin., Conclusion: This study shows the absence of amoxicillin-resistant strains, a high initial clarithromycin-resistant strains level (primary resistance), increasing after a first course of treatment, and for metronidazole a high initial level of resistance not influenced by treatment. Secondary clarithromycin-resistance of Helicobacter pylori strains following the first course of treatment could account for failure of bacterial eradication and suggests the importance of antimicrobial susceptibility.

The investigation of this outbreak took place in Niakhar (IRD project study area), a rural area located 150 km East of Dakar. Covering 30 villages, with a population of about 30,000 inhabitants, the area has been under demographic and epidemiological surveillance. In 1999, the surveillance allowed 973 cases of shigellosis to be recorded out of 1,751 cases of dysenteric diarrhoeas. The outbreak reached a peak during the raining season (73% of the cases in September and October). All the villages and all age groups were concerned. The attack rate in the population was 3%. During the same period, 22 deaths were attributed to shigellosis, leading to a lethality of 2.3%. Children under five were the most affected. The bacteriological examination isolated S. flexneri in 72% of 12 stools samples and S. dysenteriae A1 (SD1) in 14%. All serotypes were resistant to ampicillin and susceptible to quinolones. Susceptibility to cotrimoxazole was unconstant. Apart from the usual factors involved in the spread of diarrhoeas, the main reason evoked to explain the duration of the epidemic has been the lack of adequate emergency antibiotherapy treatment. Quinolones, recommended by the health authorities, could not be provided by health services. The identification of the SD1 serotype confirmed its involvement in the outbreak of shigellosis. The exact role of S. flexneri in shigellosis epidemics should be further studied.

Metronidazole was first introduced for the treatment of trichomoniasis. Now, its therapeutics use has subsequently been expanded to include protozoal and anaerobic infections. Oral administration is recommended: rosacea, perioral dermatitis, Helicobacter pylori, Trichomonas vaginalis and Giardia lamblia infections and bacterial vaginosis. Metronidazole given orally is absorbed almost completely. Metronidazole has limited plasma protein binding but can reach very favourable tissue distribution, including central nervous system and placenta. This drug is extensively metabolised by the liver to form 5 oxydative metabolites. The majority of this drug and metabolites are excreted in urine and feces. The half-life is 6 to 10 hours. The recommended dose is 500 mg three time per day and an adaptation is necessary in renal insufficiency. Metronidazole is well tolerated when administered in dosages of less than 2 g per day. Some adverse reactions appear to be related to the high dosages and treatment duration. Drug interactions with alcohol, warfarin and phenytoin have been reported. Mutagenesis and cancerogenesis is only described in mouse. Resistance, both clinical and microbiological, has been described only rarely.

The study on the sensitiveness of slow-growing anaerobes bacteria to antibiotics is delicate when you consider the technical motives that make it difficult to transpose the standard methods frequently used in microbiological laboratories. The three main methods used to determine susceptibility to antibiotics are: disk-diffusion test, antibiotics containing microdilution plates and ATB ANA (bioMérieux). The aim of this study is to compare the effectiveness of each of these methods on severe anaerobes bacteria isolated in sub-gingival flora of patients suffering from developing periodontitis (rapidly progressive periodontitis, refractory periodontitis, active stage of adult chronic periodontitis). The observed bacteria are: Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, Campylobacter rectus, Peptostreptococcus micros. Antibiotics used are: ampicilline, amoxicilline, tetracycline, erythromycine, metronidazole. The comparison of the minimal inhibitory concentrations (M.I.C) of each of these methods has permitted to show a strict correlation in the results observed with these three methods, if only the growth of the severe anaerobes bacteria on agar medium does not exceed 72 hours.

The treatment of intestinal Clostridium difficile infections rests on administration of either a glycopeptide or metronidazole. Given the current shifts in resistance patterns of anaerobes to antimicrobials, a study of the susceptibility of C. difficile to metronidazole was timely. The objective of this study was to evaluate the influence of the culture medium on the Minimal Inhibitory Concentration (MIC) of metronidazole as determined using the E-test. Thirty-one strains were grown on three different media supplemented with 5% horse blood, namely Columbia agar, Wilkens Chalgren agar, and Brucella agar. Results were compared to those obtained using the reference agar dilution method (ADM). As recommended by the French Society for Microbiology, susceptibility was defined as an MIC < or = 4 mg/L. When used on strains susceptible by the ADM, the E-test yielded lower values than the ADM with all three media. Furthermore, findings suggest that E-test results obtained with strains whose MIC is in the 4 to 8 mg/L range by the ADM should be interpreted with caution and, in some cases, tested using the ADM.

The study of radiation induced hair dysplasia in 8 day old mice allows investigations of the radiosensitizing power of a drug as early as the third day after irradiation without complicated equipment. The results being quantitative, they allow easy determination of the ER of a drug. In this study the method was applied to the action of metronidazol under anoxia.

The activity of metronidazole combined with ofloxacin was investigated by the checkerboard method in liquid medium against 60 obligate anaerobes. The bacteriostatic effect of the combination was assessed by calculating the FIC index. Two metronidazole resistant strains of Propionibacterium acnes (MIC greater than 32 mg/l) were inhibited by 0.125 mg/l of this former antibiotic in presence of an ofloxacin concentration equal to half the value of the MIC. On the 58 other anaerobic strains, the combination of metronidazole plus ofloxacin had an additive bacteriostatic effect (30 strains) or a synergistic effect (26 strains). No antagonism was noted with any strain. For selected anaerobic or mixed infections the combination of metronidazole and ofloxacin may be useful. Killing curves demonstrated that, under good anaerobic conditions, metronidazole acted rapidly against Bacteroides fragilis. At a concentration of 8 mg/l, a decrease of log10 of the population was observed after 2 hours. After a contact ranging from 1 to 8 hours, depending of the investigated strains, a bactericidal effect was observed with metronidazole.

A total of 65 bacterial strains originating mostly from subgingival plaque were tested for their susceptibilities to metronidazole, spiramycin, and their combination, ornidazole, erythromycin and tetracycline by means of an agar dilution technique. All agents were active against all anaerobic Gram-negative rods. Bacteroides gingivalis and Fusobacterium nucleatum showed marked susceptibility to metronidazole (MIC less than or equal to 0.06 microgram/ml) whereas 4-64 micrograms/ml were required to inhibit the capnophilic Actinobacillus actinomycetemcomitans and Capnocytophaga. Gram-positive facultatives were resistant to nitro-imidazoles but were inhibited at macrolide concentrations less than or equal to 0.5 microgram/ml. Except for F. nucleatum and Veillonella strains (2 less than or equal to MIC less than or equal to 128 micrograms/ml) macrolides were active against all other anaerobic bacteria tested. At concentrations less than or equal to 2 micrograms/ml the combination of spiramycin and metronidazole (2 : 1) was active against virtually all bacteria tested but our results failed to show a synergistic effect.

As shown earlier, the three drugs are effective against most anaerobic bacteria. However, with Bacteroides fragilis the geometric mean MIC of metronidazole (0.43 microgram/ml), ornidazole (0.37 microgram/ml) and tinidazole (0.20 microgram/ml) are statistically different. Moreover, and contrary to generally accepted opinion, some aerobic bacteria such as Moraxella and Bacillus can be susceptible to nitro-imidazoles. The results suggest another mechanism for the action of nitro-imidazoles, different from that previously described. This underscores the major role of the reduction of the nitrogroup by a low-redox-potential. Two strains of strictly anaerobic bacteria show a relative resistance in the microaerophilic zone.

The authors chose the problem of the isolation of bacteroides fragilis in pathological samples to present a method of identification of strict anaerobic gram negative bacteria, suitable for use in a routine bacteriological laboratory. A selection of 20 strains led them to study the mean inhibitory concentration of these germs with regard to antibiotics. From this study, two groups were obtained: one of low activity, the other of greater activity in vitro, in which one may note certain tetracyclines, clindamycin and metronidazole.

In vitro antibacterial activity of 32 antimicrobials was studied on 20 strains of Campylobacter pyloridis (CP). CP is susceptible to beta lactams, cyclins, chloramphenicol, rifampicin, macrolides, aminoglycosides, sometimes to colistin, nalidixic acid, metronidazole, never to vancomycin, trimethoprim, co-trimoxazole.

Metronidazole was administered (500 mg daily the first month, 250 mg daily the second month and, in some cases, 250 mg every other day the following months) to 62 patients suffering from rosacea or perioral dermatitis. 90 p. 100 of them improved within 2 months and Metronidazole was particularly effective against papulo-pustules. Relapses after interruption of treatment seemed to be less frequent than with Tetracycline therapy. Side-effects (gastro-intestinal disturbances) occurred in few patients but long-term tolerance remains uncertain. So, the length of treatment was less than 6 months and the drug was not given to pregnant women.

The minimal inhibitory concentrations of three antimicrobial agents were determined by two fold dilution in Wilkins Chalgren agar for over 569 anaerobes isolated and collected from 20 French hospitals. Metronidazole, cefoxitin and clindamycin inhibited respectively 95, 97 and 91% of tested strains. No metronidazole resistant strains could be found among Bacteroides fragilis group, Fusobacterium and Clostridium other than C. perfringens. Cefoxitin was the most active against C. perfringens, Gram positive cocci and non sporulated bacilli. Clindamycin resistance was observed mainly with B. fragilis and Clostridium other than C perfringens. This phenomenon occurred in most hospitals where strains were isolated.

The MIC of two hundred and seven anaerobic bacterial strains was determined by an agar dilution method for five antibiotics (piperacillin, ampicillin, carbenicillin, cefalotin, metronidazole). 100% of the strains were susceptible to carbenicillin (MIC less than or equal to 128 mg/l), 97% to piperacillin (MIC less than or equal to 16), 86% to metronidazole (MIC less than or equal to 4), 70% to ampicillin (MIC less than or equal to 4) and 68% to cefalotin (MIC less than or equal to 8). Amongst bêta-lactam compounds, piperacillin and ampicillin determined the lowest MIC for Bacteroides fragilis, Fusobacterium, Clostridium and Gram-positive cocci. Amongst Bacteroides fragilis strains, the lowest MIC were obtained with metronidazole.

In order to reduce the radioresistance due, among others, to hypoxia in solid tumors, research on radiosensitizers (especially the electron-affinic sensitizers) has been active for many years. The radiosensitization efficiency and the cytotoxic and transforming effects of a great number of substances was first studied in vitro. Then two drugs, metronidazole and misonidazole, were tested especially in vivo in animals; this research concerned their effect both on tumors and on normal tissues. After presenting an overview of the experimental results, we summarize the preliminary results of the first clinical trials with misonidazole. The general tolerance to this drug is now well known: its local influence on tumors and also normal tissues radiosensitivity is the object of most of the present clinical trials.

One hundred and fifty-two strains of Bacteroides fragilis were tested by agar dilution technique against 7 antimicrobial agents. Metronidazole at 1 microgram/ml and chloramphenicol at 8 microgram/ml inhibited all the strains tested. Cefoxitin at 32 microgram/ml and carbenicillin at 128 microgram/ml were active against nearly all strains. On the other hand, only 92% of the strains of B. fragilis were inhibited by clindamycin at 4 microgram/ml. Erythromycin and tetracycline were less active against B. fragilis.

The minimum inhibitory concentrations (MIC) of piperacillin and three other antibiotics (amoxicillin, cefoxitin, metronidazole) against 165 strains of obligate anaerobes isolated in hospitals in 1985 and 1986 were determined by the Wilkins-Chalgren agar medium dilution method. Among the 67 strains of Bacteroides fragilis, 98.5% were sensitive to piperacillin (MIC less than or equal to 128 mg/l), 100% were sensitive to metronidazole (MIC less than or equal to 4 mg/l), 11.9% were resistant to cefoxitin (MIC greater than 32 mg/l) and 46% were resistant to amoxicillin (MIC greater than 16 mg/l). The MIC50 was about 4 mg/l with piperacillin, 8 mg/l with cefoxitin and 0.5 mg/l with metronidazole. All 32 strains of Clostridium perfringens were sensitive to the 4 antibiotics tested, with an MIC50 of about 0.06 mg/l with piperacillin, 0.125 mg/l with amoxicillin and 0.5 mg/l with cefoxitin and metronidazole. All other strains of Clostridium spp. (33 in all) were sensitive to piperacillin and metronidazole; the MIC's were about 0.06 mg/l with piperacillin, 0.25 mg/l with amoxicillin and metronidazole and 0.5 mg/l with cefoxitin. Seven strains (C. innocuum 5, C. difficile 1, C. ramosum 1) were resistant to cefoxitin. All 33 strains of Peptostreptococcus and Peptococcus were sensitive to the 4 antibiotics tested. Although metronidazole still is the most effective of anti-anaerobes agents, piperacillin has proved to be effective against most anaerobic bacteria, including B. fragilis. It is clearly superior to amoxicillin and relatively superior to cefoxitin, notably against this species.

A study of the experimental chemotherapeutic activity of secnidazole as compared to metronidazole is presented, including a summary of toxicity, metabolism, pharmacokinetic studies and preliminary results from clinical trials. Secnidazole is about twice as active as metronidazole against experimental amebiasis, equiactive against trichomoniasis, and possesses low toxicity. After oral administration to man, active concentrations in the blood persist much longer than in the case of metronidazole and notably longer than for tinidazole. In the clinic, its therapeutic activity against hepatic amebiasis seems to be at least equal to that of metronidazole; it appears also to be more active against acute intestinal amebiasis, and specially more effective against E. minuta and cyst carriers. Against vaginal trichomoniasis it was as effective as metronidazole after repeated administration for several days, and the percentage recovery rate was as high after one single dose as after daily administration. The digestive tolerance seems to be very satisfactory. In view of these findings, the advantages which secnidazole might possess over other 5-nitroimidazoles already in use for the treatment of amebiasis and trichomoniasis are discussed.

The in vitro activities of amoxicillin, amoxicillin-clavulanic acid, piperacillin, cefoxitin, cefotetan, cefotaxime, cefmenoxime, ceftizoxime, latamoxef, clindamycin and metronidazole, were determined by agar dilution method for 196 clinical isolates of anaerobic bacteria. No metronidazole resistant strains could be found, 10% of tested strains were resistant to clindamycin. The majority of these strains was susceptible to amoxicillin-clavulanic acid and piperacillin; less than 10% were resistant to latamoxef, cefoxitin, cefotaxime and ceftizoxime; whereas 15 to 20% were resistant to amoxicillin, cefotetan and cefmenoxime.

A 21-year-old man presented with a 10-year history of a malabsorption syndrome of moderate severity, splenomegaly, and recurrent respiratory infections. Investigations revealed total atrophy of the villi and primary agammaglobulinemia. A gluten-free diet was ineffective. In spite of the absence of lambliasis, treatment with metronidazole produced objective clinical improvement and biological signs of healing of the malabsorption syndrome, but no alteration in the agammaglobulinemia. The authors discuss the relationship between total villous atrophy and primary agammaglobulinemias and the mode of action of metronidazole.

A comparative study of the sensitivity to metronidazole and ornidazole of 127 anaerobic or microaerophilic strains isolated from various clinical samples showed that the activity of both products was similar: the distribution of sensitive and resistant strains was identical. However, the in vitro activity level of metronidazole was slightly higher. This difference, though statistically significant, had no incidence on therapeutic indications. The determination of sensitivity towards the two nitroimidazoles was carried out by three methods: broth dilution and agar diffusion for metronidazole; and broth dilution and disk-broth for ornidazole. Two of these methods, broth dilution and disk-broth, gave concordant results. Conversely, the limits of the agar diffusion technique were shown to be related to independent biological factors such as bacterial motility and slow growth rate. The poor accuracy of this method limits its use in detecting total resistance.

Minimal inhibitory concentrations (MIC) of the combination amoxicillin + clavulanic acid (AAC) (2/1 w/w) on 84 strains of obligate anaerobes were measured by the agar diffusion method and compared to those of amoxicillin (AMO), lamoxactam (LAM) and metronidazole (MET). For the 47 Bacteroides fragilis strains tested, the mode MIC was 0.5 microgram/ml with AAC, 1-2 with MET, 0.5-1 with LAM and 8-16 with AMO. A similar range of activity was found on the 16 other strains of Bacteroides sp.. AAC and AMO have a comparable activity on Clostridium perfringens (mode MIC 0.016-0.032 microgram/ml), superior to that of LAM (mode MIC 0.125) and MET (mode MIC 0.5). AAC and AMO have an almost identical activity on Peptococci and Peptostreptococci, the MIC for both drugs being less than 0.125 microgram/ml. A similar activity was found for LAM and MET.

In vitro activity against 100 strains of Bacteroides fragilis of ticarcillin alone and combined with 4 or 8 mg of clavulanic acid was compared with those of cefoxitin, cefotaxime, ceftazidime, lamoxactam , ceftriaxone and metronidazole. The Cl 90 was 29.7 mg/l for ticarcillin alone, and 1.3 and 0.5 mg/l for ticarcillin combined with 4 and 8 mg of clavulanic acid respectively. Every strain was susceptible to ticarcillin combined with clavulanic acid (CMI less than or equal to 16 mg/l) and metronidazole (CMI less than or equal to 4 mg/l). Among the cephalosporins tested, lamoxactam (Cl 90 : 1 mg/l) was the most active, followed by cefotaxime (22.7 mg/l), cefoxitin (23 mg/l), ceftriaxone (51.2 mg/l) and ceftazidime (347 mg/l).

The minimal inhibitory concentrations (MICs) of five new quinolones were determined by agar dilution, for 50 clinical isolates of Gardnerella vaginalis. They are compared with those of metronidazole, ampicillin, erythromycin and tetracycline which are widely used for the treatment of lower genital tract infections in women. The MICs of rosoxacin and pefloxacin are high, but those of ofloxacin (MIC 50, 2 mg/l), fleroxacin (MIC 50, 2 mg/l) and ciprofloxacin (MIC 50, 1 mg/l) are lower. They can explain the effectiveness observed with this latter antibiotic in vivo, and allow their clinical experiment.

In one year and a half period 47 Clostridium difficile were isolated from stool samples. Isolates with questionable morphologic features were identified using sugars fermentation, gaz liquid chromatography (GLC). Cytotoxin assay was performed on Mac Coy cells. The comparative susceptibilities to amoxicillin-clavulanic acid (AMC), cefotetan (CTT), cefoxitin (FOX), cefotaxime (CTX), latamoxef (MOX), mezlocillin (MEZ), piperacillin (PIP), clindamycin (CLIN) and metronidazole was tested using minimal inhibition concentration (MIC) determination on Wilkins-Chalgren blood agar. CLIN, FOX, CTX, MOX were inactive, CTT is moderately inactive. All strains were susceptible to AMX, MEZ, PIP and metronidazole.