In vitro activity of gemifloxacin (SB-265805) compared with 14 other antimicrobials against intestinal pathogens

We studied the in vitro activity of gemifloxacin (SB-265805) and 14 comparator antimicrobials against 288 recent isolates of enteropathogenic bacteria (106 Salmonella: spp., 32 Hafnia alvei, 22 Yersinia enterocolitica, 21 Shigella: spp., 16 Aeromonas: spp. and 91 Campylobacter jejuni). Gemifloxacin, the other fluoroquinolones and cefotaxime were very active against all microorganisms tested except for C. jejuni. Seventy-seven per cent of isolates of C. jejuni were inhibited by erythromycin < or =0.5 mg/L. Only one strain of C. jejuni was highly resistant to this antimicrobial agent. Of the compounds tested, gentamicin was the most active in vitro. The in vitro activity of the other antibiotics tested was variable. A quinolone could be a good choice for treating gastrointestinal infections when antimicrobial therapy is indicated. For C. jejuni, another antibiotic such as erythromycin should be considered.     

In vitro activities of PD 117,596 and reference antibiotics against 448 clinical bacterial strains.

The in vitro activity of PD 117,596, a new fluoroquinolone antibiotic, was tested against 448 bacterial isolates (15 genera) by agar dilution (inoculum, 10(4) CFU per spot). The activity of PD 117,596 was compared with that of 15 antibiotics against 327 gram-negative strains and with that of 8 other antibiotics against 121 gram-positive strains. PD 117,596 demonstrated the best activity against Klebsiella spp., Enterobacter spp., Acinetobacter spp., Serratia marcescens, and Branhamella catarrhalis (MICs for 90% of the isolates [MIC90S], 0.008 to 0.25 microgram/ml). PD 117,596 (MIC90, 0.25 microgram/ml) was at least twofold more active than ciprofloxacin against Pseudomonas aeruginosa and Pseudomonas spp. PD 117,596 and ciprofloxacin were similar in activity against Escherichia coli, Proteus mirabilis, Haemophilus influenzae, H. parainfluenzae, Neisseria gonorrhoeae, Legionella pneumophila, and Campylobacter jejuni (MIC90, 0.002 to 0.125 microgram/ml). PD 117,596 was more active than ciprofloxacin against streptococcal groups A, B, C, and G, S. pneumoniae, and enterococci (MIC90S, 0.06 to 0.125 microgram/ml). Against Staphylococcus aureus, including methicillin-resistant isolates, PD 117,596 (MIC90S, 0.03 to 0.06 microgram/ml) was 4- to 16-fold more active than ciprofloxacin and was most active against Corynebacterium spp. PD 117,596 appears to be the most active fluoroquinolone to date, with excellent activity against gram-positive bacteria and enhanced activity against gram-negative aerobic-facultative bacteria.     

Susceptibility of Campylobacter fetus subsp. jejuni to Twenty Antimicrobial Agents

One hundred recent clinical isolates of Campylobacter fetus subsp. jejuni were tested by an agar dilution technique for susceptibility to each of 20 antimicrobial agents. Doxycycline and gentamicin were the most active of the drugs examined, inhibiting all strains at concentrations achievable in serum. Although the median minimal inhibitory concentration of erythromycin was low, 8% of the isolates were highly resistant. All isolates of Campylobacter fetus subsp. jejuni were relatively resistant to the beta-lactam antibiotics. Some strains were highly resistant to metronidazole and tinidazole.     

In vitro and in vivo antibacterial activities of BO-1341, a new antipseudomonal cephalosporin.

BO-1341, a new antipseudomonal semisynthetic cephalosporin, was evaluated for in vitro and in vivo antibacterial activities in comparison with ceftazidime, cefotaxime, and cefoperazone. The in vitro activity of BO-1341 was generally superior or comparable to the activities of the reference antibiotics against clinical isolates of the family Enterobacteriaceae. BO-1341 was highly active against Pseudomonas aeruginosa (MIC for 90% of the strains tested, 1.56 micrograms/ml), Pseudomonas maltophilia (MIC for 50% of the strains tested, 1.56 micrograms/ml), and Acinetobacter calcoaceticus (MIC for 90% of the strains tested, 3.13 micrograms/ml). Furthermore, BO-1341 was highly active against P. aeruginosa isolates resistant to the other antibiotics. Of 199 P. aeruginosa isolates tested, only 2 were resistant to BO-1341. These two strains were also resistant to ceftazidime, cefotaxime, and cefoperazone. Haemophilus influenzae, Branhamella catarrhalis, and nonenteric streptococci were also susceptible to BO-1341, but Staphylococcus aureus, Streptococcus faecalis, and Bacteroides fragilis were not susceptible to the compound. The protective efficacy against experimental infections in mice caused by nine strains of gram-negative bacteria, including P. aeruginosa, reflected the potent in vitro activity.     

Comparative in vitro activity of ciprofloxacin against Campylobacter spp. and other bacterial enteric pathogens

A comparison was made of the in vitro activity of ciprofloxacin (Bay o 9867) with nine other antibiotics against isolates of Campylobacter jejuni, Salmonella spp., Shigella spp., Yersinia enterocolitica, Clostridium difficile, Vibrio spp., and Escherichia coli. Minimum inhibitory concentrations of ciprofloxacin were the lowest of any compound tested for all organisms except C. difficile.     

深圳市南山区腹泻患者弯曲菌感染及病原学特征分析

目的获得本地区秋季腹泻患者弯曲菌的感染现状及病原学特征。方法收集深圳市南山区2018年9 — 11月腹泻患者的粪便标本,采用双孔滤膜法分离培养弯曲菌并应用荧光聚合酶链式反应（PCR）方法进行菌种鉴定。 应用脉冲场凝胶电泳（PFGE）和多位点序列分型（MLST）对分离菌株进行分子分型,应用琼脂稀释法获得菌株对11种抗生素的最小抑菌浓度（MIC）。 根据菌株的序列分型（ST）结果,结合既往菌株分型数据进行本地区菌株的遗传聚类分析。结果共采集腹泻患者粪便标本150份,其中男性患者74例,女性患者76例,年龄在1～86岁之间。 150份粪便标本中共分离到弯曲菌18株,检出率为12.00%（18/150）。 菌种鉴定发现,空肠弯曲菌占77.78%（14/18）,结肠弯曲菌占22.22%（4/18）。 14株空肠弯曲菌可分为11种PFGE带型,8个ST型别,以ST9763最多（35.71%,5/14）,是本研究新发现ST型别。 14株空肠弯曲菌对四环素全部耐药,对红霉素、阿奇霉素、泰利霉素、庆大霉素、链霉素及克林霉素100.00%敏感。 ST型别最小生成树聚类分析结果表明,不同宿主来源菌株没有显著聚集性,腹泻患者分离菌株分布在不同来源的组群中。结论采用双孔滤膜法提高了腹泻患者中弯曲菌的检出率。本地区弯曲菌的感染仍以空肠弯曲菌为主, 分离菌株对四环素类、喹诺酮类抗生素呈现较高的耐药特征,分离的空肠弯曲菌ST呈弥散分布特点。     

Activity of BMS284756 (T-3811) tested against anaerobic bacteria, Campylobacter jejuni, Helicobacter pylori and Legionella spp.

BMS284756, a novel des-fluoro (6) quinolone (formerly T-3811), was tested for activity and spectrum using reference agar dilution (AD) and Etest (AB BIODISK, Solna, Sweden) methods. The antimicrobial activities of BMS284756, ciprofloxacin, gatifloxacin, levofloxacin, and trovafloxacin were evaluated against Campylobacter jejuni (38 strains), Helicobacter pylori (21 strains), Legionella spp. (66 strains), and 197 anaerobic isolates. BMS284756 (MIC(90), 0.008 microg/mL) was four-fold more active than gatifloxacin and trovafloxacin against H. pylori strains. Gatifloxacin and BMS284756 (MIC(50), 0.03 microg/mL) were > or = two-fold more active than levofloxacin against C. jejuni, but their spectrums were judged equivalent overall (89.4% susceptible). Against the Legionella spp., ciprofloxacin and levofloxacin (MIC(90), 0.25 microg/mL) had two-fold greater activity compared to gatifloxacin or BMS284756, but all strains were considered inhibited at clinically achievable levels. BMS284756 and trovafloxacin (MIC(90), 2 and 4 microg/mL, respectively) were four-to-eight-fold more potent than other comparators against the Gram-negative anaerobic species. Against the Gram-positive anaerobes (dominated by Clostridium difficile; 61 strains), BMS284756 activity was generally reduced, but equivalent or superior to trovafloxacin (68% inhibited at < or = 4 microg/mL). Inter-method comparisons (Etest versus AD) of BMS284756 MIC values showed a high correlation for C. jejuni and anaerobes (93.3 to 97.6% +/- two log (2) dilution steps). In conclusion, BMS284756 was very active against C. jejuni, H. pylori, Legionella spp. and most anaerobes, thus the potential role of this des-fluoro compound for treatment of infections caused by these fastidious species warrants further investigation.     

Comparison of antimicrobial susceptibility patterns of Campylobacter jejuni and Campylobacter coli

To determine whether employing antibiograms is useful to separate Campylobacter jejuni and Campylobacter coli, we determined the MICs of 12 antibiotics for 104 human clinical strains and 74 swine strains. Of 74 swine strains, 5 (7%) were hippurate positive, as were 93 (89%) of 104 human strains. The 12 antimicrobial agents tested were ampicillin, amoxicillin, clindamycin, chloramphenicol, erythromycin, furazolidone, norfloxacin, nalidixic acid, rosoxacin, rosaramicin, tetracycline, and Sch 32063. Isolates from humans were significantly (P less than 0.001) more susceptible than swine strains to clindamycin, erythromycin, rosaramicin, and Sch 32063. Of 11 human hippurate-negative strains, 3 (27%) were resistant to clindamycin, erythromycin, rosaramicin, and Sch 32063, compared with 1 of 93 (1%) hippurate-positive strains. Nearly all human and swine strains were susceptible to furazolidone and nalidixic acid. Campylobacter isolates from humans and swine have different antibiograms, and the susceptibility to certain antibiotics, such as clindamycin, may be helpful for differentiation of C. jejuni from C. coli.     

In vitro susceptibility of Campylobacter jejuni to 27 antimicrobial agents and various combinations of beta-lactams with clavulanic acid or sulbactam.

The in vitro susceptibility of human isolates of Campylobacter jejuni was investigated with 27 antibiotics and 8 combinations of beta-lactams with clavulanic acid or sulbactam. Ansamycin, the new quinolines, erythromycin, and cefpirome were the most active drugs against C. jejuni; amoxicillin, ampicillin, cefotaxime, and ceftazidime 90% of the isolates, greater than or equal to 50 mg/liter). The activity of various beta-lactams was unchanged by the addition of clavulanic acid or sulbactam.     

空肠弯曲菌耐药谱特征分析

目的 分析十几年间我国空肠弯曲菌临床分离株对10种抗生素耐药谱特征,了解我国空肠弯曲菌耐药的变迁趋势。 方法 采用世界卫生组织(WHO)全球食源性病原菌感染网络(GFN)推荐的弯曲菌琼脂稀释法,测定1995年至今分离的116株空肠弯曲菌对6类10种抗生素的最小抑菌浓度(MIC)。 结果 经对实验结果整体分析,甲硝唑的总体耐药率最高为97.4%(113/116),四环素为82.8%(96/116),环丙沙星为80.2%(93/116),萘啶酸为79.3%(92/116),左氧氟沙星和氨苄西林耐药率相同,为40.5%(47/116),氯霉素为18.1%(21/116),庆大霉素为8.6%(10/116),链霉素为4.3%(5/116),最低为红霉素0(0/116)。随着时间的推进,萘啶酸、环丙沙星、左氧氟沙星和氨苄西林的MIC有明显增高趋势;四环素、红霉素、庆大霉素、氯霉素和甲硝唑的MIC值变化不明显;链霉素的MIC值变化有下降的趋势。6.1%的菌株出现了8种抗生素多重耐药的结果,且菌株均出现在2010年后。经统计学分析,萘啶酸、环丙沙星、链霉素、庆大霉素、氯霉素和氨苄西林6种抗生素在2001年前、2001-2005年、2006-2010年和2010年后4个时间段中耐药率差异有统计学意义。 结论 空肠弯曲菌对红霉素、庆大霉素以及链霉素3种抗生素依旧保持了较高的敏感性,对萘啶酸、环丙沙星、左氧氟沙星、四环素、甲硝唑以及氨苄西林6种抗生素产生了较大程度的耐药。     

Susceptibilities of Campylobacter jejuni isolates from Germany to ciprofloxacin,moxifloxacin, erythromycin,clindamycin, and tetracycline

To elucidate Campylobacter jejuni resistance to antibiotics in Germany, MICs of ciprofloxacin, moxifloxacin, erythromycin, clindamycin, and tetracycline were determined (using agar dilution) for 144 clinical isolates. The data indicate a considerable ciprofloxacin resistance (45.1%) without a clonal relationship of the strains and a greater in vitro activity of moxifloxacin, erythromycin, and clindamycin.     

In vitro activities of new fluoroquinolones against Campylobacter jejuni and Campylobacter coli isolates obtained from humans in 1980 to 1982 and 1997 to 2001

The antibacterial activities of three newly developed fluoroquinolones (gatifloxacin, levofloxacin, and moxifloxacin) against a total of 307 gastrointestinal human isolates of Campylobacter jejuni and Campylobacter coli collected during 1980 to 1982 and 1997 to 2001 were examined and compared to those of ciprofloxacin and the unrelated antibacterial agents, clarithromycin, erythromycin, and tetracycline by using the agar plate dilution method. All of the fluoroquinolones exhibited a good activity against Campylobacter, and some of them were more active than ciprofloxacin, the macrolides, and tetracycline. Among the fluoroquinolones, gatifloxacin and moxifloxacin showed the highest anticampylobacter activity, with MICs at which 50% of the isolates tested are inhibited (MIC(50)s) and MIC(90)s of 0.125 and 4 microg/ml, respectively; the MIC(50) for both levofloxacin and ciprofloxacin was 0.25, and the MIC(90)s were 16 and 32 microg/ml, respectively. About 30% of the strains were found to be resistant to at least one fluoroquinolone. Resistance to gatifloxacin occurred in 9.8% of the isolates tested, and resistance to the other fluoroquinolones occurred in 19.9 to 27.4% of the isolates tested; the frequency of cross-resistance was 35.7 to 100%. An increase in fluoroquinolone resistance from 0% in 1980 to 1982 to 11.8 to 29% in 1997 and 1998, 8.2 to 31.8% in 1999 and 2000, and 12.1 to 30.3% in 2001 was found. A total of 61.4 to 73.2% of the C. jenuni strains resistant to erythromycin, clarithromycin, and/or tetracycline were susceptible to fluoroquinolones; gatifloxacin showed the highest percentage of inhibition. These results show that the newer fluoroquinolones with their potent activity could be used to treat infections with C. jejuni and C. coli. However, when these drugs are used, one must consider the increase in resistance and the high cross-resistance to these antimicrobial agents.     

The E-Test and Campylobacter jejuni.

The E-Test is a recently introduced method for performing antimicrobial susceptibility tests. We compared the E-Test to the broth microdilution test and to the standard agar dilution test by using five antimicrobial agents tested against 55 clinical isolates of Campylobacter jejuni from 11 locations in USA (group 1). Later, we selected 30 strains (group 2), which were more resistant than the original survey isolates. Erythromycin, tetracycline, and ciprofloxacin were tested on both groups of organisms. When the three test methods were compared with each other at +/- 1 log2 dilution, the E-test gave the best overall agreement, with 85% of all strains being within acceptable limits. Category interpretation of erythromycin (drug of choice) results was a problem using current NCCLS guideline breakpoints. For the E-Test and the agar dilution method, 82% of the strains were in the intermediate category; but with the broth microdilution method, only 16.4% of the isolates were interpreted as intermediate. If the susceptible category breakpoint was raised to less than or equal to 2 micrograms/ml, then only 3% of the C. jejuni isolates would be interpreted as intermediate by any of the three methods. Our preference for antimicrobial susceptibility testing of C. jejuni is either E-Test or agar dilution at 42 degrees C for 16 hr.     

Susceptibility of clinical isolates of Campylobacter jejuni to sixteen antimicrobial agents.

The activities of 16 antimicrobial agents against 103 clinical isolates of Campylobacter jejuni were tested. All the strains were susceptible to kanamycin and gentamicin. Chloramphenicol, nalidixic acid, and clindamycin were active against most of the strains. More than one-third of the strains were resistant to the tetracyclines and 12.5% were resistant to erythromycin.     

Comparative in vitro activity of ceftibuten (Sch 39720) against bacterial enteropathogens.

Ceftibuten is a new orally active cephalosporin with significant bioavailability. Its in vitro activity was compared with those of other agents against 383 strains of enteric pathogens derived from clinical specimens. Ceftibuten was very active against the strains of the family Enterobacteriaceae tested (overall MIC for 90% of strains tested, 0.25 microgram/ml) but was less active against Campylobacter jejuni (MIC for 90% of strains, 16 micrograms/ml). The MBC was one to two dilutions higher than the corresponding MICs for most pathogens tested.     

Antibacterial activities of a new stabilized thienamycin, N-formimidoyl thienamycin, in comparison with other antibiotics.

The in vitro activity of a new crystalline derivative of thienamycin, N-formimidoyl thienamycin (MK0787), was tested against 46 laboratory reference strains and 2,158 clinical isolates of gram-positive and -negative bacteria, including anaerobes, and compared with cefoxitin, cefaxolin, carbenicillin, and amikacin. MK0787 was significantly more active than the reference antibiotics against most bacteria tests. MK0787 was 16- to 500-fold more active than the other antibiotics against Staphylococcus aureus, Streptococcus pneumoniae, and group A and group B streptococci, inhibiting most isolates at concentrations less than 0.031 micrograms/ml. The inhibition concentration against over 90% of 156 strains of Streptococcus faecalis was 1 micrograms/ml. MK0787 had slightly less activity than carbenicillin against Haemophilus influenzae. The minimal inhibitory concentrations of MK0787 against strains of Enterobacter spp., Citrobacter spp., Serratia marcescems. Pseudomonas aeruginosa, and Clostridium difficile that are resistant to currently available antibiotics were less than or equal to 4 micrograms/ml. The only species found resistant to MK0787 was Pseudomonas maltophilia, which was equally nonsusceptible to the other reference antibiotics.     

Susceptibilities of anaerobic bacteria to N-formimidoyl thienamycin (MK0787) and to other antibiotics.

The susceptibilities of 462 clinical anaerobic bacterial isolates to N-formimidoyl thienamycin and 16 other currently available and investigational antibiotics were determined by the agar dilution technique. N-Formimidoyl thienamycin was significantly more active than the reference antibiotics against most organisms tested, especially Bacteroides sp., including clindamycin-resistant strains. All 462 isolates were inhibited by 4 micrograms of N-formimidoyl thienamycin per ml, and no resistant strains were found in the species tested. N-Formimidoyl thienamycin was less active (i.e., had a higher 50% minimal inhibitory concentration) against Fusobacterium sp. than clindamycin, SM-1652, and piperacillin, and less active against Clostridium difficile than metronidazole, but was equally active or more active than the other reference antibiotics tested.     

Comparative in-vitro activity of four peptide antibiotics against penicillin-resistant Streptococcus pneumoniae isolated from cerebrospinal fluid (CSF).

The in-vitro activity of four peptide antibiotics against 43 penicillin-resistant Streptococcus pneumoniae isolated from cerebrospinal fluid (CSF) was evaluated. The activity of SKF104662 was slightly greater to that of vancomycin, teicoplanin and daptomycin (MICs for 90% of the isolates tested 0.06, 0.25, 0.12 and 0.25 mg/L, respectively) and superior to the other 15 drugs tested. The serotype of these penicillin-resistant strains was also determined. The strains that belonged to the predominant serotype 9 were resistant only to penicillin. All six erythromycin- and clindamycin-resistant strains belonged to serotype 6 and three of them were also resistant to chloramphenicol and tetracycline (plus penicillin).     

Antimicrobial susceptibilities of bacteria associated with periodontal disease.

A total of 193 bacterial strains were tested for their susceptibilities to 14 antimicrobial agents. Penicillin G was active at 2 U/ml against 98% of the oral isolates. Other antibiotics with good activity were cefoperazone, moxalactam, Sch 29,482, and clindamycin. Metronidazole was active against more than 90% of the anaerobic bacteria and Capnocytophaga but was inactive against most other microaerophilic and facultative strains.     

Multidrug resistance in Campylobacter jejuni strains collected from Finnish patients during 1995-2000

OBJECTIVES: The resistance of Campylobacter jejuni to fluoroquinolones is increasing globally. This study was performed to delineate those antimicrobial agents that are effective in vitro against ciprofloxacin-resistant C. jejuni isolates and potentially suitable for the treatment of severe disease when fluoroquinolone resistance or multidrug resistance is known or suspected. METHODS: During 1995-2000 we collected 376 C. jejuni strains, of which 354 were of foreign origin from multiple countries and 22 were of domestic origin. The MICs of 12 antimicrobial agents against the isolates were determined. RESULTS: Of the 376 strains, 174 (46%) were resistant to ciprofloxacin. Among other antimicrobials, resistance was most common to tetracycline (46%) and ampicillin (17%). Of the ciprofloxacin-resistant strains, 68% and 25%, respectively, were resistant to tetracycline and ampicillin, and 3% were resistant to erythromycin, gentamicin or clindamycin. One (0.6%) ciprofloxacin-resistant isolate was resistant to co-amoxiclav and none was resistant to imipenem. Resistance to three or more antimicrobial groups was detected in 22% of the isolates. Multidrug resistance was significantly associated with ciprofloxacin resistance (33% versus 12%; P<0.01). Eight (2%) strains were resistant to macrolides, of which 75% were also resistant to ciprofloxacin, but none was resistant to co-amoxiclav or imipenem. CONCLUSIONS: Macrolides still appear to be the first-choice alternative for suspected C. jejuni enteritis, if antimicrobial treatment is needed. The in vitro susceptibilities suggest that clinical trials to treat enteritis caused by multidrug-resistant C. jejuni with co-amoxiclav, and life-threatening infections with a carbapenem, may be valuable.