Correlation Between the In Vivo And In Vitro Antimicrobial Properties of Commercially Available Mouthwash Preparations

Summary

The effectiveness of six commercially available mouthwashes against common buccal organisms was studied. The minimum inhibitory concentrations (MIC) for two of the studied mouthwashes (Corsodyl and Oraldene) against buccal organisms were determined in Todd Hewitt medium with or without 5% serum. The concentration of the active substance in these two mouthwashes was in excess of the corresponding MIC. When the medium was supplemented with serum, lower MIC values were observed. Kill-time determinations, used at half the concentration of the normal preparation, revealed a rapid lethal effect for all tested mouthwashes. The slowest lethal effect was observed with Fluocaril mouthwash.

When mouthwashes were tested in volunteers, an immediate significant fall in salivary bacterial counts was produced by all except Fluocaril. With the latter mouthwash the decrease was significant 2-30 minutes after rinsing. The bacterial levels returned to pre-rinse levels after 30 minutes for Listerine, after 90 minutes for both Oraldene and Mint and after 180 minutes for Corsodyl, Fluocaril and Sansilla mouthwashes. The results indicate that there is a good correlation between in vivo efficacy and in vitro determination of all mouthwash preparations.     

Antiseptic effect of a novel alcohol-free mouthwash: a convenient prophylactic alternative for high-risk patients

We developed an efficacious and non-irritant mouthwash that is alcohol-free and that has a low concentration of chlorhexidine, in order to be used for preventing oral cavity infections in immunocompromised and cancer patients. The novel mouthwash solution was tested for its antimicrobial efficacy against both free floating (planktonic) and the biofilm forms of Candida albicans. The solution was also tested against Klebsiella pneumoniae, Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus (MRSA), using a modification of a previously published method. The activity of the novel mouthwash was also compared with that of three commercially available mouthwashes. The experimental mouthwash showed efficacy against C. albicans, both in free-floating form and in biofilm. With higher concentration of chlorhexidine, the solution was also efficacious in inhibiting the growth of K. pneumoniae, P. aeruginosa, and MRSA. The antiseptic activity of the alcohol-free mouthwash against other bacterial organisms and C. albicans was comparable to other commercially available alcohol-based mouthwash solutions. A novel alcohol-free mouthwash solution, that has low concentration of chlorhexidine, showed antiseptic effect against planktonic and biofilm forms of C. albicans and against K. pneumoniae, P. aeruginosa, and MRSA.     

A controlled evaluation of an allopurinol mouthwash as prophylaxis against 5-fluorouracil-induced stomatitis

Pursuant to a promising report suggesting that an allopurinol mouthwash could have a protective effect against 5-fluorouracil (5-FU)-induced stomatitis, the authors performed a randomized, placebo-controlled, double-blind, crossover study. Seventy-seven patients, receiving their first 5-day course of chemotherapy with 5-FU +/- leucovorin, were assigned to use a mouthwash containing 20 mg of allopurinol or a placebo. The mouthwash was administered every hour for four doses commencing with each chemotherapy dose. The severity of subsequent mucositis was graded (on a 0-4 scale) by the attending physician and also by a patient-completed questionnaire. There was trend toward less mucositis in the placebo group with mean physician-judged mucositis scores of 1.3 for placebo and 1.8 for allopurinol (P = 0.07) and mean patient-judged mucositis scores of 1.5 for placebo and 1.9 for allopurinol (P = 0.15). There were no substantial differences in mucositis attributable to the two mouthwashes in the patients who crossed-over on their second cycle of chemotherapy. These data demonstrate that the tested allopurinol mouthwash regimen does not offer any protective effect against 5-FU-induced mucositis.     

The effectiveness of commonly used mouthwashes for the prevention of chemotherapy-induced oral mucositis: a systematic review

Daily chlorhexidine mouthwash is often recommended for preventing chemotherapy-induced oral mucositis. Povidone-iodine, NaCl 0.9%, water salt soda solution and chamomile mouthwash are also recommended. However, the effectiveness of these mouthwashes is unclear. Therefore, we performed a systematic review to assess the effectiveness of mouthwashes in preventing and ameliorating chemotherapy-induced oral mucositis. Based on study quality, three out of five randomized controlled trials were included in a meta-analysis. The results failed to detect any beneficial effects of chlorhexidine as compared with sterile water, or NaCl 0.9%. Patients complained about negative side-effects of chlorhexidine, including teeth discoloration and alteration of taste in two of the five studies on chlorhexidine. The severity of oral mucositis was shown to be reduced by 30% using a povidone-iodine mouthwash as compared with sterile water in a single randomized controlled trial. These results do not support the use of chlorhexidine mouthwash to prevent oral mucositis.     

Evaluation of ciprofloxacin's activity against recent clinical isolates

The in vitro antibacterial activity of ciprofloxacin, a new quinoline carboxylic acid, was tested against 1671 recently clinically isolated bacterial strains, by measuring the minimum inhibitory concentrations (MIC). Comparisons were made with other quinolones: nalidixic acid, norfloxacin, and other drugs: piperacillin, cefoxitin, cefotetan, ceftazidime, tobramycin, rifampin, tetracycline, chloramphenicol. Ciprofloxacin was very active against the tested species and was the most active drug against all the bacterial strains, with a geometric mean, a MIC50 and MIC90 of 0.27, 0.12 and 2 micrograms/ml, respectively.     

Radiation-induced mucositis: a randomized clinical trial of micronized sucralfate versus salt & soda mouthwashes

Oral mucositis is one of the major toxicities caused by radiation therapy (RT) treatments to the head and neck. The clinical efficacy of sucralfate (Carafate R) mouthwash for head and neck cancer patients (HNC) is not consistent across studies. In this study, it was hypothesized that if the particles in the original sucralfate suspension were micronized (i.e., ≤25 microns) then the coating action of the mouthwash in the oral cavity would be enhanced. The purpose of this pilot study was to compare the efficacy of micronized sucralfate (Carafate R) mouthwash and salt & soda mouthwash in terms of the severity of the mucositis, the severity of mucositis-related pain, and the time required to heal RT-induced mucositis in patients with HNC. Severe mucositis and related pain can interfere with the ingestion of food and fluids, so patients' body weights were measured as well. All patients in this randomized clinical trial carried out a systematic oral hygiene protocol called the PRO-SELF: Mouth Aware (PSMA) Program. Patients who developed RT-induced mucositis anytime during their course of RT were randomized to one of the two mouthwashes and followed to the completion of RT and at one month following RT. Two referral sites were used for the study. Repeated measures occurred with the following instruments/variables: MacDibbs Mouth Assessment and weight. Demographic, disease, and cancer treatment information was also obtained. Thirty patients successfully completed the study. The typical participant was male (70%), married/partnered (70%), White (63%), not working or retired (73%), and had an average of 14.5 years of education (SD=3.7). T-tests and Chi-square analyses with an alpha set at 0.05 were used to compare differences between the two mouthwashes. No significant differences were found in the number of days to onset of mucositis (i.e., 16±8.4 days). When patients had their worst MacDibbs score, (i.e., the most severe mucositis), there were no significant differences between the mouthwashes as to MacDibbs score, the RT dose received, or ratings of pain (upon swallowing). Similarly, at the end of RT, no significant differences were found between mouthwashes as to MacDibbs scores or ratings of pain (upon swallowing). At the one-month follow-up assessment no significant differences were found between the mouthwashes in MacDibbs scores or pain ratings (upon swallowing). The analysis of the efficacy of the two mouthwashes revealed no significant differences in the time to heal (in days) from the RT-induced mucositis. The findings from this trial provide important clinical information regarding cost analysis of RT mucositis management. Given that there is no significant difference in efficacy between micronized sucralfate and salt & soda, use of the less costly salt & soda is prudent and cost-effective.     

从人口腔细胞获取基因组DNA作基因多态性分析的可行性

背景与目的口腔洗液上皮细胞应用于检测基因多态性已有多篇文献报道,但口腔洗液中含有少量食物残渣是否给基因多态性检测带来干扰已备受关注。本研究比较口腔上皮细胞和血样品DNA中某些基因的多态性,同时以同样的方法检测食物中动植物组织的DNA,以排除食物残渣干扰实验结果的可能性,并探讨改良口腔洗液上皮细胞收集方法。方法收集62例人口腔洗液,每例收集40ml,加10ml异丙醇固定。其中30例进行细胞涂片检查上皮细胞含量,同时采集外周血5ml。另采集人们常食用的米饭、青菜、毛豆、苹果、猪肉、牛肉、鸡肉、鸭肉。所有样品分别经蛋白酶K消化,酚氯仿抽提,乙醇沉淀提取基因组DNA。结合PCR-RFLP技术进行口腔细胞和血细胞基因多态性分析比较。并用Alu片段测定人口腔洗液、外周血及上述食物DNA。结果62例口腔洗液DNA含量为(135.15±64.30)μg(22.36～330.70μg);其中30例经镜检含有人上皮细胞者有75%～95%,DNA含量为(143.44±61.64)μg(51.01～283.58μg);30例外周血中DNA含量为(91.19±38.01)μg(30.83～178.63μg)。琼脂糖凝胶电泳结果显示62例口腔上皮细胞和30例血样品均具有高分子量DNA,其中61例口腔细胞和30例血样品均能扩增茁-globin、Alu以及NAT2、GSTM1、GSTT1、CYP1A1和CYP2E1基因片段,但所有的食物DNA全部未能扩增。30例口腔洗液与相应血液的基因多态性结果一致。结论口腔洗液DNA大部分来源于人,即使含有少量食物残渣也不会给基因多态性分析带来干扰,其基因多态性检测结果与血样品DNA分析结果完全一致。     

Evaluation of pefloxacin activity against recent clinical isolates

The in-vitro antibacterial activity of pefloxacin, a new quinolone carboxylic acid, was tested against 1140 bacterial strains, recently clinically isolated, by measuring the minimum inhibitory concentrations. Comparisons were made with other quinolones (enoxacin, norfloxacin, flumekin, oxolinic acid, pipemidic acid) and other drugs (piperacillin, cefotaxime, ceftazidime, gentamicin, tobramycin, amikacin) widely used for the treatment of bacterial infections. Pefloxacin was very active against the tested species and was the most active drug against all the bacterial strains, with a geometric mean of MICs, a MIC 50 and MIC 90 of 0.27, 0.12 and 4 microg/ml respectively.     

Microbiological profile of teicoplanin

The in-vitro antibacterial activity of teicoplanin, a new glycopeptide antibiotic, previously named teichomycin A2, was tested against 258 gram-positive anaerobic bacterial strains, recently clinically isolated, by measuring the minimum inhibitory concentrations. Comparisons were made with other drugs, clindamycin, rifampicin, netilmicin, enoxacin, vancomycin, widely utilized for the treatment of bacterial infections. Teicoplanin was very active against the tested species and showed the highest activity against all the tested strains, with a geometric mean of MICs, a MIC 50 and MIC 90 of 0.125, 0.12 and 0.5 microg/ml, respectively.     

In vitro evaluation of BI 397, a novel glycopeptide antimicrobial agent.

BI 397, a semi-synthetic amide derivative of the experimental glycopeptide, MDL 62,476 (A40926), has excellent in vitro activity against a wide range of Gram-positive organisms. In this extensive study, 630 contemporary (1998-2000) Gram-positive isolates were selected from various resistance surveillance studies for their resistance patterns to fluoroquinolones, macrolides-lincosamides-streptogramins, beta-lactams and glycopeptide agents. The BI 397 spectrum of activity was similar to that of other glycopeptides with a MIC90 of < or =0.5 microg/ml for all tested isolates with the exception of vancomycin-resistant enterococci Van A; (MIC90, 32 microg/ml). BI 397 was more potent than vancomycin and teicoplanin against Staphylococcus aureus (2- to 8-fold), beta-haemolytic streptococci (equal to >16-fold), viridans group streptococci (equal to >32-fold), and Corynebacterium spp. including C. jeikeium (8- to >16-fold). BI 397 was also more active than quinupristin/dalfopristin against all Gram-positive organisms tested with the exception of oxacillin-susceptible S. aureus, against which it had equal activity. BI 397 has little activity against Haemophilus influenzae (MIC90, 64 microg/ml) or other Gram-negative bacilli (MIC90, >64 microg/ml). BI 397 exhibited bacteriostatic activity (like the vancomycin control) versus most species, but was bactericidal against tested Streptococcus pneumoniae. In vitro testing conditions with blood supplemented or free protein containing media elevated BI 397 MIC results, and the 30-microg disk seems acceptable for further disk diffusion test development. Animal pharmacokinetic data published elsewhere suggest that BI 397 may be dosed less frequently than teicoplanin and the results of early studies in humans are awaited with interest, especially when treating teicoplanin-refractory coagulase-negative staphylococci.     

Effect of moxifloxacin on bacterial pathogenicity factors in comparison with amoxicillin, clarithromycin and ceftriaxone

Moxifloxacin is a recent fluoroquinolone with an antibacterial spectrum encompassing both aerobic Gram-negative and Gram-positive strains, as well as anaerobic bacteria. In this study the activity of moxifloxacin against Streptococcus pneumoniae, Staphylococcus aureus, Moraxella catarrhalis, Haemophilus influenzae, Escherichia coli, Proteus mirabilis and Pseudomonas aeruginosa, and effects of subinhibitory concentrations on bacterial morphology and adhesion properties were compared with those of amoxicillin, clarithromycin and ceftriaxone. The in vitro activity of moxifloxacin against Gram-positive and Gram-negative pathogens was equal to or better than that of comparators. Subinhibitory concentrations of moxifloxacin significantly affected bacterial morphology of S. pneumoniae, M. catarrhalis, H. influenzae and P. aeruginosa, leading to formation of spherical forms and filaments. Moreover, bacterial adhesion to buccal cells and fibroblasts was reduced after treatment with 1/4 and 1/8 X MIC of moxifloxacin. In conclusion, subinhibitory concentrations of moxifloxacin remarkably interfere with some bacterial pathogenic factors, thereby contributing to its antimicrobial activity.     

Daptomycin in vitro activity tested against Gram-positive strains collected from European and Latin American medical centers in 2003

Daptomycin, a cyclic lipopeptide, was susceptibility tested against clinical bacterial isolates consecutively collected in hospitals located in Europe (4,731 strains) and Latin America (1,007 strains) in 2003 as part of a continuing surveillance program. The bacterial isolates tested were Gram-positive pathogens that included staphylococci, streptococci and enterococci. The isolates were tested for susceptibility using broth microdilution methods (broth with 50 mg/L Ca++ for testing daptomycin). All isolates, except two Enterococcus faecium strains from Europe, were inhibited at daptomycin MIC of < or = 4 mg/L. In addition, 99.4 and 97.3% of isolates were inhibited at daptomycin MIC of < or = 2 and < or = 1 mg/L, respectively. Except for one Staphylococcus aureus and one viridans group streptococci from Europe and one coagulase-negative staphylococci from Latin America, all staphylococcal and streptococcal isolates were inhibited by 1 mg/L of daptomycin. Resistance to other compounds (vancomycin, oxacillin, and penicillin) did not influence daptomycin activity. The activity of daptomycin was very similar in both geographic regions evaluated and demonstrated the same MIC distribution as isolates evaluated in studies in the United States. The results of this study showed that daptomycin continues to be very active against clinical isolates of Gram-positive cocci isolated in Europe and Latin America.     

The role of PK/PD parameters to avoid selection and increase of resistance: mutant prevention concentration

The continuing escalation of antimicrobial resistant human pathogens and the limited number of new antimicrobial agents under development has dictated that our knowledge on the emergence of resistance and any potential strategies to slow the rate at which resistance occurs is of paramount importance. Investigations with fluoroquinolones resulted in the mutant prevention concentration (MPC) concept which represents a novel in vitro measurement of fluoroquinolone potency. In essence, the MPC defines the antimicrobial drug concentration threshold that would require an organism to simultaneously possess two resistance mutations for growth in the presence of the drug. An alternative definition is the drug concentration that prevents the growth of first-step resistant mutants or the minimal inhibitory concentration of the most resistant organism present in the heterogeneous bacterial population when tested against > or =10(9) organisms. From in vitro investigations, the new fluoroquinolones (gatifloxacin, gemifloxacin, moxifloxacin) were all found to have lower MPC values than did levofloxacin against clinical isolates of Streptococcus pneumoniae. Ciprofloxacin was found to have lower MPC values than levofloxacin against clinical isolates of Pseudomonas aeruginosa. When MPC data is applied to achievable and sustainable serum drug concentrations in the body, estimation of the time the serum drug concentration exceed both MIC and MPC values can be determined. This data along with kill data allows for an estimate of the amount of time drug concentration needs to exceed MIC/MPC values to not only result in significant kill but also to minimize resistance development. To date, MPC measurements have been determined in in vitro microbiological and pharmacological models and animal and human data are being investigated. The data summarized in this overview detail resistance issues for P. aeruginosa, S. pneumoniae and other pathogens. Also presented is a summary of the MPC concept and investigations completed to date. A brief summary of fluoroquinolone mechanisms of action and resistance is presented. Finally, some preliminary investigations with other classes of compounds are discussed. To date, very limited data is available to conclude if the MPC concept does or does not apply to other classes of antimicrobial agents.     

Susceptibility of Ureaplasma urealyticum to tetracycline, doxycycline, erythromycin, roxithromycin, clarithromycin, azithromycin, levofloxacin and moxifloxacin

The in vitro activity of tetracycline, doxycycline, erythromycin, roxithromycin, clarithromycin, azithromycin, levofloxacin and moxifloxacin was tested against 63 clinical isolates of Ureaplasma urealyticum. The minimal inhibitory concentrations (MICs) and the minimal bactericidal concentrations (MBCs) were determined by the broth microdilution method in A7 medium. The MIC(50) and MIC(90) of the tested agents after 24 h of incubation were as follows: tetracycline, 0.5 and 2.0 μg/ml; doxycycline, 0.125 and 0.25 μg/ml; erythromycin, 2.0 and 8.0 μg/ml; roxithromycin, 2.0 and 4.0 μg/ml; clarithromycin, 0.25 and 1.0 μg/ml; azithromycin, 2.0 and 4.0 μg/ml; levofloxacin, 1.0 and 2.0 μg/ml; and moxifloxacin, 0.5 and 0.5 μg/ml, respectively. The MIC values after 24 h and 48 h incubation differed by no more than one dilution for all the agents with the exception of doxycycline (two dilution difference for MIC(90)). Overall, moxifloxacin was the most active agent in vitro against U. urealyticum, with the narrowest difference between MIC and MBC values, followed closely by levofloxacin. Clarithromycin was the most active macrolide.     

Interrelationship between the pharmacokinetics and pharmacodynamics of cefaclor advanced formulation in patients with acute exacerbation of chronic bronchitis

Cefaclor advanced formulation (cefaclor AF) is an extended-release form of the oral cephalosporin cefaclor. When cefaclor AF 750 mg twice-daily and cefaclor immediate release 500 mg three-times-a-day are compared there is a skew to the right of the pharmacokinetic profile and higher levels are achieved. Based on this pharmacokinetic finding, we examined the relationship between the bacterial susceptibility to cefaclor (MIC), the achieved cefaclor AF serum and sputum concentrations, and in vivo eradication of the bacteria in 36 patients with acute exacerbations of chronic bronchitis. The mean peak concentrations in serum and sputum 5 h after administration were 8.6 microg/ml (95% CI: 8.1 microg/ml - 9.1 microg/ml) and 1.5 microg/ml (95% CI: 1.4 microg/ml - 1.7 microg/ml), respectively. Cefaclor was always detectable 8 h after administration. At post therapy, treatment was successful in 31 (86.1%) patients. Cefaclor concentrations in serum persisted above the MIC for more than 40% of dosing interval in 31 subjects, and those in sputum in 24 patients. Treatment was successful in all subjects with percent of time above the MIC in serum of >40%, whereas the time that levels in sputum stayed above the MIC was not the pharmacodynamic parameter that correlated best with therapeutic efficacy for cefaclor. Our data demonstrate that when cefaclor AF is dosed twice-daily, the in vivo pharmacodynamic susceptibility breakpoint is 8 microg/ml. The good activity and pharmacokinetics of cefaclor AF provide serum concentrations higher than the MIC of Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis for more than 40% of the validated dosing interval. Therefore, it might be considered for first choice treatment of acute exacerbations of chronic bronchitis.     

Salivary acetaldehyde increase due to alcohol‐containing mouthwash use: A risk factor for oral cancer

Increasing evidence suggests that acetaldehyde, the first and genotoxic metabolite of ethanol, mediates the carcinogenicity of alcoholic beverages. Ethanol is also contained in a number of ready‐to‐use mouthwashes typically between 5 and 27% vol. An increased risk of oral cancer has been discussed for users of such mouthwashes; however, epidemiological evidence had remained inconclusive. This study is the first to investigate acetaldehyde levels in saliva after use of alcohol‐containing mouthwashes. Ready‐to‐use mouthwashes and mouthrinses (n = 13) were rinsed in the mouth by healthy, nonsmoking volunteers (n = 4) as intended by the manufacturers (20 ml for 30 sec). Saliva was collected at 0.5, 2, 5 and 10 min after mouthwash use and analyzed using headspace gas chromatography. The acetaldehyde content in the saliva was 41 ± 15 μM, range 9–85 μM (0.5 min), 52 ± 14 μM, range 11–105 μM (2 min), 32 ± 7 μM, range 9–67 μM (5 min) and 15 ± 7 μM, range 0–37 μM (10 min). The contents were significantly above endogenous levels and corresponding to concentrations normally found after alcoholic beverage consumption. A twice‐daily use of alcohol‐containing mouthwashes leads to a systemic acetaldehyde exposure of 0.26 μg/kg bodyweight/day on average, which corresponds to a lifetime cancer risk of 3E?6. The margin of exposure was calculated to be 217,604, which would be seen as a low public health concern. However, the local acetaldehyde contents in the saliva are reaching concentrations associated with DNA adduct formation and sister chromatid exchange in vitro, so that concerns for local carcinogenic effects in the oral cavity remain. © 2009 UICC     

The effect of fresh human serum on ofloxacin bactericidal activity

We have studied the possibility of an increase in ofloxacin bactericidal activity when it is combined with fresh human serum. The tested strains were 10 clinical isolates of Klebsiella pneumoniae. From among our strains 5 were susceptible to serum bactericidal activity and 5 were found to be resistant. We selected two serum concentrations (15 and 35%) to test against susceptible strains and two (55 and 75%) to test against resistant strains in combination with the minimum inhibitory concentration (MIC), 1/2MIC and 1/4MIC of ofloxacin. The results show a slight variability among the tested strains depending on microbiological characteristics of single strains, however, the serum + ofloxacin combination was advantageous. Only one exception was observed: a resistant strain that had an increased survival percentage against ofloxacin and serum in combination.     

Daptomycin In Vitro Activity Tested Against Gram-Positive Strains Collected from European and Latin American Medical Centers in 2003

Abstract

Daptomycin, a cyclic lipopeptide, was susceptibility tested against clinical bacterial isolates consecutively collected in hospitals located in Europe (4,731 strains) and Latin America (1,007 strains) in 2003 as part of a continuing surveillance program. The bacterial isolates tested were Gram-positive pathogens that included staphylococci, streptococci and enterococci. The isolates were tested for susceptibility using broth microdilution methods (broth with 50 mg/L Ca⁺⁺ for testing daptomycin). All isolates, except two Enterococcus faecium strains from Europe, were inhibited at daptomycin MIC of ≤4 mg/L. In addition, 99.4 and 97.3% of isolates were inhibited at daptomycin MIC of ≤2 and ≤1 mg/L, respectively. Except for one Staphylococcus aureus and one viridans group streptococci from Europe and one coagulase-negative staphylococci from Latin America, all staphylococcal and streptococcal isolates were inhibited by 1 mg/L of daptomycin. Resistance to other compounds (vancomycin, oxacillin, and penicillin) did not influence daptomycin activity. The activity of daptomycin was very similar in both geographic regions evaluated and demonstrated the same MIC distribution as isolates evaluated in studies in the United States. The results of this study showed that daptomycin continues to be very active against clinical isolates of Gram-positive cocci isolated in Europe and Latin America.     

Antimicrobial activity of daptomycin tested against gram-positive strains collected in European hospitals: results from 7 years of resistance surveillance (2003-2009)

Daptomycin is a cyclic lipopeptide approved by the European medicines Agency (EMEA) for the treatment of complicated skin and soft tissue infections (cSSTI) and Staphylococcus aureus bacteremia and endocarditis. We evaluated the in vitro activity of daptomycin and comparators tested against clinical isolates from european hospitals over a 7-year period (2003-2009). A total of 36,769 consecutive isolates were collected in 34 medical centers located in 13 European countries, Turkey and Israel. the collection included S. aureus (18,352; 27.2% oxacillin-resistant [MRSA]); coagulase-negative staphylococci (CoNS; 6,874), Enterococcus spp. (7,241; 9.4% vancomycin-resistant), β-hemolytic (3,009), viridans group streptococci (1,176), and Streptococcus bovis/gallolyticus (107). The organisms were isolated mainly from patients with bloodstream infection (56%) or cSSTI (23%). Daptomycin was very active against S. aureus and CoNS (MIC(50/90), 0.25/0.5 mg/l for both organisms), and its activity was not adversely influenced by oxacillin resistance. All Enterococcus faecalis strains were susceptible to daptomycin (MIC(50/90), 1/1 mg/l). Daptomycin (MIC(50/90), 2/2 mg/l; 100.0% susceptible) and linezolid (MIC(50/90), 1/2 mg/l; 99.7% susceptible) were the most active agents tested against vancomycin-resistant E. faecium. Vancomycin- resistant and -susceptible enterococcal strains were equally susceptible to daptomycin. Daptomycin was also active against β-hemolytic streptococci (MIC(50/90), 0.06/0.25 mg/l; 100.0% susceptible), viridans group streptococci (MIC(50/90), 0.25/0.5 mg/l; 99.8% susceptible) and S. bovis (MIC(50/90), 0.06/0.12 mg/l; 100.0% susceptible).In summary, daptomycin was very potent against this large collection (36,769) of Gram-positive organisms isolated in european hospitals, and its activity remained stable across the 7-year period evaluated (2003-2009), using reference methods and interpretive criteria. Decreases in daptomycin potency were not observed since EMEA approval and widespread clinical use, and emerging resistance to other compounds did not adversely influence daptomycin activity against contemporary Gram-positive species.     

Evaluation of Ciprofloxacin’s Activity against Recent Clinical Isolates

Summary

The in vitro antibacterial activity of ciprofloxacin, a new quinoline carboxylic acid, was tested against 1671 recendy clinically isolated bacterial strains, by measuring the minimum inhibitory concentrations (MIC). Comparisons were made with other quinolones: nalidixic acid, norfloxacin, and other drugs: piperacillin, cefoxitin, cefotetan, ceftazidime, tobramycin, rifampin, tetracycline, chloramphenicol.

Ciprofloxacin was very active against the tested species and was the most active drug against all the bacterial strains, with a geometric mean, a MIC₅₀ and MIC₉₀ of 0.27, 0.12 and 2 μg/ml, respectively.