Antimicrobial activity in vitro of cefaclor, a new oral cephalosporin

The antimicrobial activity of cefaclor, a new orally administered cephalosporin derivative, was studied in vitro against a variety of Gram-positive and Gram-negative clinical isolates. Both penicillin-resistant and penicillin-susceptible strains of Staphylococcus aureus were susceptible to cefaclor, with mean MICs of 1.44 and 0.93 microgram/ml, respectively. However, the MBC for penicillin-resistant S. aureus was higher than that for the penicillin-susceptible strains. All strains of Streptococcus pyogenes, Streptococcus viridans, and Streptococcus pneumoniae tested were highly susceptible to cefaclor; all strains of Streptococcus faecalis were highly resistant to cefaclor. Strains of Escherichia coli, Klebsiella sp., Proteus mirabilis, and Hemophilus influenzae were susceptible to cefaclor. Eighty per cent of strains of H. influenzae were inhibited by 5 micrograms/ml of cefaclor. Most strains of Enterobacter sp., indole-positive Proteus, Pseudomonas sp., and Serratia sp. were resistant to cefaclor.     

The sensitivity of gram-negative and gram-positive bacteria to ofloxacin

The in vitro antimicrobial activity of ofloxacin, a new fluorinated quinolone, was evaluated against 165 Gram-negative rods, both fermentative and non-fermentative, and against 57 Gram-positive strains (coagulase-positive and -negative staphylococci both methicillin-resistant and -susceptible, and Streptococcus faecalis). Minimal inhibitory concentrations were determined by using the macrodilution test and the activity was compared with nalidixic acid, norfloxacin, ampicillin, piperacillin, ceftazidime and gentamicin for Gram-negative rods; norfloxacin and gentamicin for Staphylococcus strains; and norfloxacin, ampicillin, piperacillin and gentamicin for enterococci. Ofloxacin inhibited all fermentative Gram-negative bacteria tested, in a range of 0.05-3.12 mcg/ml, and had good antimicrobial activity against non-fermentative Gram-negative strains: it inhibited 90% of Acinetobacter and 80% of P. aeruginosa tested, at 3.12 mcg/ml. Ofloxacin had a high antimicrobial activity against Staphylococcus and Enterococcus strains tested.     

Susceptibilities of clinical isolates to antibacterial agents. Focusing mainly on ofloxacin (first report). Reported by the Research Group for Testing Ofloxacin Susceptibility of Clinical Isolates

Susceptibility tests were carried out on a variety of clinically isolated pathogens using the susceptibility disc method at 197 hospitals in Japan between May, 1985 through March, 1986. These tests were organized by the Research Group for Testing Ofloxacin Susceptibility on Clinical Isolates, and the results were statistically analyzed. This paper describes a comparison of susceptibilities of clinical isolates including Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Streptococcus pneumoniae, Neisseria gonorrhoeae, Escherichia coli, Enterobacter aerogenes, Enterobacter cloacae, Citrobacter freundii, Klebsiella pneumoniae subsp. pneumoniae, Proteus mirabilis, Morganella morganii, Serratia marcescens, Haemophilus influenzae, Pseudomonas aeruginosa, Acinetobacter calcoaceticus, Acinetobacter sp. and Campylobacter jejuni to ofloxacin (OFLX) and conventional antibacterial drugs. The results obtained were summarized as follows. 1. OFLX showed strong antibacterial activity against S. aureus, S. epidermidis, N. gonorrhoeae, E. coli, E. aerogenes, E. cloacae, C. freundii, K. pneumoniae subsp. pneumoniae, P. mirabilis, M. morganii, H. influenzae, A. calcoaceticus, Acinetobacter sp. and C. jejuni and only a few strains were resistant to OFLX. Moreover, OFLX has superior antibacterial activity against many species compared not only to norfloxacin but also to most of the conventional antibacterial drugs. 2. When studied by sampled materials such as sputum, urine, abscesses and otorrhea, OFLX occasionally showed different actions against the same species from different sources. Almost species from the urinary isolates were less sensitive than those from the sputum.     

巴洛沙星的体外抗菌作用研究

目的评价巴洛沙星的体外抗菌作用。方法以琼脂稀释法测定巴洛沙星对临床分离菌的最低抑菌浓度，并与有关抗菌药进行比较；测定巴洛沙星的杀菌作用，观察巴洛沙星的抗菌活性影。结果巴洛沙星对革兰氏阳性菌及革兰氏阴性菌具广谱抗菌活性，尤其对葡萄球菌、肺炎球菌、肠球菌等革兰氏阳性菌活性优于诺氟沙星、氧氟沙星和环丙沙星。巴洛沙星有较强的杀菌作用，其MBC与MIC相一致，在体外具有较长的抗菌后效应。结论巴洛沙星是一种广谱抗菌药，抗菌作用强，临床应用前景好。     

The resistance of recent clinical isolates against isepamycin, other aminoglycosides and injectable beta-lactams

Clinical isolates collected from clinical facilities across Japan in 1998 were tested against five aminoglycosides and three beta-lactams. The resistance of 50 strains each of methicillin sensitive Staphylococcus aureus, methicillin resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, Escherichia coli, Citrobacter freundii, Klebsiella pneumoniae, Enterobacter sp., Serratia sp., Pseudomonas aeruginosa and Proteus sp. (P. mirabilis 25 strains and P. vulgaris 25 strains) to the aminoglycosides isepamicin (ISP), amikacin (AMK), gentamicin, tobramycin and dibekacin, and to the beta-lactams imipenem, ceftazidime and piperacillin (all three known to be effective against P. aeruginosa) were investigated using a micro liquid dilution method with the following results: 1. ISP was effective against all strains except for 14% of MRSA, 2% of Proteus sp., and 4% of P. aeruginosa. 2. Six strains of MRSA were resistant to all eight drugs; however, in these cases ISP exhibited a relatively low minimum inhibitory concentration (MIC) compared to the other compounds. 3. Four strains of MRSA were resistant to all drugs except ISP. MRSA was the only isolate to demonstrate a resistance to seven or more drugs. 4. Twenty-one strains of MRSA and 1 strain of P. aeruginosa were resistant to six drugs; however, all of these were susceptible to both ISP and AMK. 5. Against all strains tested, ISP generally exhibited a lower MIC compared to AMK. These results suggest that, even ten years after its entering the market, ISP is still an aminoglycoside having a high anti-bacterial activity against a wide range of clinical isolates.     

司帕沙星与其他5种抗菌药体外抗菌活性比较研究

测定了司帕沙星对临床分离的１９９ 株致病菌的体外抗菌活性并与氧氟沙星、环丙沙星、头孢唑啉、头孢噻肟、阿米卡星的抗菌活性进行比较。司帕沙星对革兰阳性菌的ＭＩＣ９０为０．１２５～０．５ｍ ｇ／Ｌ,对金葡球菌、化脓链球菌的抑菌率均为１００％ ,强于氧氟沙星、环丙沙星;对革兰阴性菌也具有良好的体外抗菌活性,与氧氟沙星、环丙沙星相似。不同细菌接种量和不同浓度血清对其抗菌活性无明显影响,仅在ｐＨ５．０ 时抗菌活性略有下降     

Comparative in vitro potency of amoxycillin-clavulanic acid and four oral agents against recent North American clinical isolates from a global surveillance study

The in vitro activity of amoxycillin-clavulanic acid was compared with four comparator oral antimicrobial agents; ampicillin, azithromycin, cefuroxime and trimethoprim-sulphamethoxazole against 4536 recent clinical isolates covering 29 species isolated in the US and Canada between 1997 and 1999. Based upon Minimum inhibitory concentrations (MICs), amoxycillin-clavulanic acid was the most active agent against many Gram-positive species and phenotypes including methicillin susceptible Staphylococcus aureus (MSSA) Staphylococcus epidermidis, Enterococcus faecalis, Streptococcus pyogenes, Streptococcus pneumoniae including penicillin intermediate and macrolide resistant strains and was as active as ampicillin against Streptococcus agalactiae, penicillin resistant S. pneumoniae and viridans streptococci. Against Enterobacteriaceae amoxycillin-clavulanic acid in general, displayed weak activity with only Proteus mirabilis and Proteus vulgaris displaying levels of susceptibility above the 90th percentile. Amoxycillin-clavulanic acid had significant activity against many species of Gram-negative non-Enterobacteriaceae including Haemophilus influenzae, Haemophilus parainfluenzae and Moraxella catarrhalis but negligible activity against Burkholderia cepacia, Pseudomonas aeruginosa and Stenotrophomonas maltophilia. Amoxycillin-clavulanic acid continues to retain excellent activity against the majority of targeted pathogens despite 20 years of clinical use.     

Susceptibility in vitro of gram-positive aerobe and anaerobe bacteria to ofloxacin

Ofloxacin is a new fluoroquinolone derivative active against Gram-positive and Gram-negative bacteria including obligate anaerobes. In this study the in vitro activity of ofloxacin was evaluated against 325 Gram-positive organisms freshly isolated from clinical specimens, in comparison with that of ampicillin, erythromycin, clindamycin and ceftazidime. Susceptibility tests indicated that the MIC90 was 2 mg/l (range 0.25-2) against both methicillin-susceptible (MS) and methicillin-resistant (MR) Staphylococcus aureus. A value of 2 mg/l (range 0.5-4) was also found for all other staphylococci. The MIC of ofloxacin was 8 mg/l for 90% of Streptococcus faecalis (range 1-16), Str. faecium (range 2-8) and members of JK group (range 0.5-16). Propionibacterium acnes strains were all inhibited by 2 mg/l and 90% of Clostridia spp. (range 2-16) by 8 mg/l. Ofloxacin activity compared favourably with that of ampicillin, erythromycin, clindamycin and ceftazidime determined on the same isolates. MBC and time-kill studies indicated that this compound is rapidly bactericidal against enterococci. The great intrinsic activity against MS and MR staphylococci, refractory enterococci and JK bacteria may make ofloxacin a useful adjunct to the therapeutic arsenal.     

Antibacterial activities of ofloxacin against recent isolates from patients with community-acquired infections

In order to survey antibacterial activities of ofloxacin (OFLX) against 1,440 bacterial strains isolated from patients with community-acquired infections in 1987 and 1990, minimum inhibitory concentrations (MICs) of the drug as well as those of other new quinolones and oral cephems were determined. The following conclusions were reached. 1. Comparison of the MIC distribution for strains isolated in 1987 with those in 1990 suggested a tendency toward an increase in the frequency of OFLX-resistant isolates with the passage of time of Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Citrobacter spp., Klebsiella ssp., Enterobacter spp., Proteus vulgaris, Morganella morganii, Providencia spp., and Acinetobacter calcoaceticus. Most common elevations of MIC values against these bacteria were observed in MIC80 and MIC90 values, while no significant alteration was observed in MIC50 values. However, MIC50's of OFLX against Serratia marcescens and Pseudomonas aeruginosa were relatively high for strains isolated in both 1987 and 1990. Most of the OFLX-resistant strains of S. aureus seemed to be methicillin-resistant (MRSA). Furthermore, MIC80 of OFLX against coagulase-negative staphylococci was high in strains isolated in both 1987 and 1990. 2. Susceptibility of Streptococcus spp. was evaluated only in strains isolated in 1990. The results were comparable to those reported by others in the early 1980s. 3. Bacteria which showed no or infrequent emergence of OFLX-resistant strains even in 1990 were Proteus mirabilis, Haemophilus influenzae, Neisseria gonorrhoeae, Campylobacter spp. and Peptostreptococcus spp. 4. Recently isolated strains from patients with community-acquired infections showed a tendency toward an increase of the frequency of OFLX-resistant strains among many bacteria. However, the bacteria which contained high percentages of OFLX-resistant strains except for MRSA were so-called less-virulent bacteria, and in the other bacteria elevations of MIC values were only observed in MIC80 and MIC90. These results suggested that OFLX preserved a potent antibacterial activity against bacteria which were major causative pathogens in community-acquired infections.     

Comparative in vitro activity of LY 127935 (6059-S), seven cephalosporins, three aminoglycosides, carbenicillin, and ticarcillin

LY 127935 (6059-S), a new semi-synthetic beta-lactam antibiotic was tested simultaneously with 6 cephalosporins, 3 aminoglycosides, carbenicillin and ticarcillin against 398 clinical isolates of Gram-negative bacilli and Gram-positive cocci. Many of the organisms were selected for study because of known resistance to one or more of the clinically available antibiotics tested. Escherichia coli, Klebsiella, Serratia and Providencia were susceptible to LY 127935. Some resistant strains of Enterobacter, Proteus, Pseudomonas aeruginosa and Acinetobacter were also resistant to LY 127935, but many of the strains resistant to other antibiotics were susceptible to LY 127935. The activity of LY 127935 against Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus viridans and Streptococcus bovis was similar to that of cephalexin and cephradine. LY 127935 was not active against methicillin-resistant S. aureus nor enterococcus.     

Susceptibilities of clinical isolates to antibacterial agents. A study mainly focused on ofloxacin (the second report). Reported by the Research Group for Testing ofloxacin Susceptibility on Clinical Isolates

Susceptibilities of various clinical isolates to ofloxacin (OFLX) and other antibacterial drugs were examined at 128 hospital laboratories in 36 prefectures throughout Japan between April, 1986 and March, 1987. The results were totalized with an emphasis mainly on OFLX and were compared with data obtained in the previous year. In this study, identification and susceptibility tests of the isolates were carried out at each hospital laboratory and the tests were performed according to the 1-dilution or 3-dilution disc method in which susceptibilities are classified into 4 grades: , ++, +, and -. Similarly to the study performed in the previous year, species showing susceptibilities to OFLX included Staphylococcus aureus (4,205 strains), Staphylococcus epidermidis (2,009 strains), Entercoccus faecalis (1,697 strains), Streptococcus pneumoniae (702 strains), Escherichia coli (4,097 strains), Klebsiella pneumoniae (1,375 strains), Enterobacter cloacae (762 strains), Enterobacter aerogenes (296 strains), Citrobacter freundii (406 strains), Proteus mirabilis (613 strains), Morganella morganii (320 strains), Serratia marcescens (869 strains), Haemophilus influenzae (1,282 strains), Pseudomonas aeruginosa (4,206 strains), Acinetobacter calcoaceticus (351 strains), Acinetobacter sp. (415 strains), and Campylobacter jejuni (151 strains). Neisseria gonorrhoeae (26 strains) were exceptional due to their smaller number this time than that of the previous year and only the susceptibility to OFLX was investigated with this species. As results, OFLX showed strong antibacterial activities (similar to the previous year) against S. aureus, S. epidermidis, N. gonorrhoeae, E. coli, K. pneumoniae, E. cloacae, E. aerogenes, C. freundii, P. mirabilis, M. morganii, H. influenzae, A. calcoaceticus, Acinetobacter sp., and C. jejuni. However, when these susceptibilities shown in the present study were compared to those obtained in the previous year, many species showed decreases in the occurrence of or increases in -, though they were rather small changes. The following species were not totalized in the previous year due to their low numbers but were summarized in combination with those examined in this study: Streptococcus pyogenes (944 strains), Streptococcus agalactiae (815 strains), Enterococcus faecium (146 strains), Branhamella catarrhalis (135 strains), Citrobacter diversus (128 strains), Klebsiella oxytoca (873 strains), Proteus vulgaris (438 strains), Serratia liquefaciens (266 strains), Pseudomonas cepacia (433 strains), Pseudomonas putida (154 strains), Xanthomonas maltophilia (272 strains), Vibrio parahaemolyticus (120 strains), Bacteroides fragilis (98 strains),     

Antimicrobial activities of ceftriaxone against clinically isolated strains]

Antibiotic activities (MICs) of ceftriaxone (CTRX) against 1,210 strains of bacteria including 28 spp. isolated in 1987 and 1990 were compared with those of other cephems. 1. When compared to data on clinically isolated strains reported in the early 1980s, strains of the following species isolated in 1990 showed extremely elevated MIC90s of CTRX: Staphylococcus spp., Streptococcus pneumoniae, Escherichia coli, Citrobacter spp., Enterobacter spp., Serratia spp., Proteus vulgaris, Morganella morganii and Providencia spp. No changes were observed in MIC90s between the 2 periods for microorganisms such as Streptococcus pyogenes, Haemophilus influenzae, Klebsiella pneumoniae, Proteus mirabilis and Peptostreptococcus spp. 2. The MIC90 of CTRX to S. pneumoniae was high because a large number of benzylpenicillin (PCG)-insensitive S. pneumoniae (PISP) was present among this species. The MIC80 to Bacteroides fragilis group was also high because highly resistant B. fragilis and B. thetaiotaomicron were isolated in large proportions among the bacteria of this group. Other oxime-type cephems also had high MICs against the above mentioned bacteria. Therefore, a further evaluation has to be made with regard to activities of oxime-type cephems such as CTRX against PISP and B. fragilis group. 3. Sample strains included, in high ratios, methicillin-resistant Staphylococcus aureus (MRSA), cephamycin-resistant as well as oxime-type cephem-resistant intestinal bacteria, Gram-negative bacteria, and new-quinolone-resistant bacteria. Some of there resistant bacteria are also CTRX-resistant, and CTRX had insufficient activities against them. 4. With regard to the assessment of changes of frequencies of specific drug-resistant bacteria, including those with CTRX-resistance from year to year, the authors would like to point out the following comment of theirs made in 1989 and 1991, which appears to be increasing its significance, "Subjects of future studies should include dose on the mechanisms for the acquisition of bacterial resistance to entire beta-lactam antibiotics and the social circumstances in which resistant bacteria appear". 5. It appears that those strains resistant to cephems including CTRX are increasingly found among clinically isolated strains in recent years. CTRX, however, was found still effective against most clinical pathogens. Furthermore, considering that CTRX is one of the few drugs which sustain high blood concentrations of active forms we concluded that CTRX is a useful cephem-group antibiotic.     

Antibacterial activity of cephem antibiotics against isolates from clinical specimens at the Yokohama City University Hospital

Minimum inhibitory concentrations (MICs) of cephem antibiotics against 405 strains belonging to 17 species of clinical isolates were investigated using the standard method of the Japanese Congress of Chemotherapy. The results obtained are summarized below. Cephem antibiotics showed weak antibacterial activities against Enterococcus sp., B. fragilis and S. marcescens. S. pneumoniae, S. agalactiae, E. coli, K. pneumoniae and P. mirabilis were susceptible to cephem antibiotics. Cephem antibiotics of the 1st and the 2nd generations showed weak antibacterial activity against Citrobacter sp. and E. cloacae, while cephem antibiotics of 3rd generation had a good antibacterial activity against these species. Cephem antibiotics of the 2nd and the 3rd generations showed high antibacterial activity against H. influenzae and indole positive Proteus group. Cefoperazone showed high antibacterial activity against P. aeruginosa. Resistance to latamoxef, ceftizoxime and cefoxitin was observed among Staphylococcus sp., while the MICs of other antibiotics against Staphylococcus sp. were fairly low. Number of strains resistant to the 3rd cephem antibiotics seems to be increasing because the 3rd generation of cephem antibiotics have been used frequently. Further investigation will be required on resistant organism to these antibiotics including beta-lactamase producing strains.     

Antibacterial activity of cefpodoxime against clinical isolates in 2000 and 2001

As the post-marketing surveillance of cefpodoxime proxetil (Banan), MICs of cefpodoxime (CPDX, an active form of Banan) against 1090 clinical isolates of 22 species from 15 medical institutions all over Japan from June 2000 to March 2001 were measured using the broth microdilution method approved by the Japanese Society of Chemotherapy and compared with those of oral cephem antibacterials, cefaclor, cefdinir, cefditoren, and cefcapene. In this study, remarkable change in the activity of CPDX was observed in Streptococcus pneumoniae and Haemophilus influenzae compared with the susceptibility in the studies before Banan was launched. This cause is considered to be the increase in the incidence of the following resistant strains: penicillin-intermediate S. pneumoniae (47.3%), penicillin-resistant S. pneumoniae (PRSP, 15.1%), and beta-lactamase-negative ampicillin-resistant (BLNAR) H. influenzae (24.0%), which were scarcely isolated in 1989 when Banan was launched. Other tested drugs also exhibited low activity against these resistant strains. However, CPDX showed comparatively good activity with MIC90 of 2 micrograms/mL against PRSP. Against methicillin-susceptible Staphylococcus spp., Streptococcus pyogenes, Streptococcus agalactiae, and Moraxella catarrhalis, CPDX also showed comparatively good activity with MIC90 of < or = 4 micrograms/mL, which was almost equal to that in the studies before its marketing. Against quinolones-resistant Neisseria gonorrhoeae, CPDX showed excellent activity with MIC90 of 0.5 microgram/mL. Against members of the family Enterobacteriaceae except for Citrobacter freundii, Enterobacter spp., Proteus vulgaris, and Morganella morganii, CPDX showed good activity. However, in Escherichia coli, Klebsiella spp. Proteus spp., and Providencia spp., there are some high-resistant strains to all tested drugs including CPDX. Against Peptostreptococcus spp., MIC90 of CPDX was 8 micrograms/mL and its MIC range was widely distributed from 0.03 to 32 micrograms/mL, which were similar to those in the studies before its marketing. In this study, CPDX showed the decrease in the activity against several species as did other drugs tested, but against most of species tested, CPDX maintained good activity. Furthermore, it is necessary to pay much attention to the trend of resistant strains.     

Antibacterial activity of ciprofloxacin against fresh clinical isolates from superficial suppurative foci

The minimum inhibitory concentrations (MICs) of 5 drugs (ciprofloxacin (CPFX), and 4 drugs used as standard) were determined to investigate antibacterial potencies of CPFX against bacterial strains isolated in 1989 from superficial suppurative foci. The clinical isolates tested included 375 strains from 11 aerobic bacterial species, and 50 strains from 2 anerobic bacterial genera (group) for a total of 425 isolates. Interpreting MIC level distributions of these drugs as the expression of antibacterial potencies, the results are as follows. 1. When activities of new-quinolone antibiotics were tested, we found that, CPFX expressed far superior antibacterial potency to ofloxacin (OFLX) and norfloxacin (NFLX) against coagulase-negative staphylococci, Enterococcus faecalis, Enterococcus faecium, Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Proteus mirabilis, Proteus vulgaris, Morganella morganii, Pseudomonas aeruginosa and Peptostreptococcus spp., although the activity of CPFX against Bacteroides fragilis group was weaker than that of OFLX, and CPFX had similar activity against Staphylococcus aureus to OFLX. 2. In comparison to beta-lactam antibiotics, CPFX was inferior to amoxicillin (AMPC) against E. faecalis and inferior to AMPC and cefaclor (CCL) against Peptostreptococcus spp. Against all other bacterial species, however, CPFX expressed superior antibacterial potency to AMPC and CCL. 3. Scattered findings of low sensitivity or resistance to CPFX were observed among the S. aureus, E. faecalis, E. faecium, P. vulgaris, M. morganii, P. aeruginosa and B. fragilis (group) species, but with an exception of E. faecium, the incidence of resistance strains was low.     

Synthesis and biological activity of new heterocyclic structures: [1,3]thiazino[2,3-i]purine, thiazolo[3,2-c] [1,2,3]triazolo[4,5-e]pyrimidine and [1,2,3]triazolo [4', 5': 4,5] pyrimido[6,1-b][1,3]thiazine.

Some derivatives of thiazolo[3,2-c]pyrimidine, pyrimido[6,1-b][1,3]thiazine, thiazolo[2,3-i]purine, [1,3]thiazino[2,3-i]purine, thiazolo[3,2-c][1,2,3]triazolo[4,5-e]pyrimidine and [1,2,3]triazolo[4',5':4,5]pyrimido[6,1-b][1,3]thiazine were prepared. The compounds were tested for antimicrobial and antimycotic activity on a number of strains, namely, Escherichia coli, Proteus vulgaris, P. mirabilis, Pseudomonas aeruginosa, Salmonella sp., Staphylococcus aureus, Streptococcus faecalis, Bacillus subtilis, Sarcina lutea, Candida albicans, Aspergillus sp., and for antiviral activity on Herpes simplex virus, Type 1 (HSV-1), Vesicular stomatitis virus (VSV) and Coxsackievirus B5 (CoxB5). The compounds proved to be devoid of activity against viruses, mycetes and gram-negative bacteria, while some of them exhibited a modest activity against gram-positive bacterial strains.     

Ofloxacin clinical pharmacokinetics.

Ofloxacin is a new fluoroquinolone with a spectrum of activity similar to other fluoroquinolones with activity which includes Chlamydia trachomatis, Mycobacterium spp., Mycoplasma spp. and Legionella pneumophila. Through its additional mechanisms of action, ofloxacin may be less susceptible to the development of resistance from Staphylococcus aureus commonly seen with currently available fluoroquinolones. The impact of these findings cannot be evaluated without further clinical experience. The pharmacokinetics of ofloxacin are characterised by almost complete bioavailability (95 to 100%), peak serum concentrations in the range of 2 to 3 mg/L after a 400mg oral dose and an average half-life of 5 to 8h. In comparison with other available quinolones, elimination is more highly dependent on renal clearance, which may lead to more frequent dosage adjustments in patients with impaired renal function. Ofloxacin appears less likely to affect the pharmacokinetics of drugs (e.g. theophylline) which commonly interact with fluoroquinolones such as ciprofloxacin and enoxacin. The properties of ofloxacin make it a therapeutic alternative to currently available fluoroquinolones.     

Moxifloxacin activity against clinical isolates compared with the activity of ciprofloxacin

The activity of moxifloxacin, a new 8-methoxyquinolone, was compared in vitro with the activity of ciprofloxacin against clinical strains isolated from various sites of infection. The mode MIC values of moxifloxacin were superior to those of ciprofloxacin against Streptococcus pneumoniae, methicillin-susceptible and -resistant Staphylococcus aureus, Enterococcus spp., Escherichia coli and Acinetobacter spp., while ciprofloxacin was more active against Klebsiella pneumoniae and Pseudomonas spp. Both antibiotics had similar activity against Haemophilus influenzae, Moraxella catarrhalis and Enterobacter spp.     

Multicentre study of the in vitro evaluation of moxifloxacin and other quinolones against community acquired respiratory pathogens.

The in vitro activity of moxifloxacin was compared with that of ciprofloxacin, levofloxacin, ofloxacin and trovafloxacin against 710 strains (180 Streptococcus pneumoniae, 180 Haemophilus influenzae, 160 Moraxella catarrhalis and 190 Streptococcus pyogenes) isolated from patients with community-acquired respiratory tract infections. MIC values for moxifloxacin, trovafloxacin were 0.25/0.25, 0.03/0.03, 0.06/0.03 and 0.125/0.0125 mg/l for S. pneumoniae, H. influenzae, M. catharralis and S. pyogenes. Based upon the MIC(90) values and the MIC distributions, moxifloxacin and trovafloxacin were the most active of the quinolones tested. They showed enhanced activity against Gram-positive organisms including penicillin non susceptible S. pneumoniae strains. Moxifloxacin was also highly active against ciprofloxacin-resistant S. pneumoniae strains.     

A54145 a new lipopeptide antibiotic complex: microbiological evaluation

A54145 complex is made up of eight factors; A, A1, B, B1, C, D, E, and F which were active in vitro (MIC 0.25 approximately greater than 32 micrograms/ml) against Gram-positive aerobic organisms. The complex, factor B and B1 were found to be active against two strains of Clostridium perfringens. A calcium dependence study on some of the factors showed that their in vitro antibacterial activity was greatly enhanced by the presence of calcium (50 mg/liter) in the media. Resistance build-up was seen when Staphylococcus sp. and Streptococcus sp. were passed seven times in the presence of sublethal concentrations of A54145 antibiotics. This resistance disappeared immediately when the resistant organisms were passed in the absence of the antibiotics. Factor A was very effective against Staphylococcus aureus and Streptococcus pyogenes infections in mice (sc ED50s of 3.3 approximately 2.4 mg/kg x 2, respectively). Factor B was more active against S. pyogenes in vivo (sc ED50, 0.9 mg/kg x 2). Acute mouse toxicities were determined with these antibiotics. Semisynthetic derivatives were evaluated.