Antimicrobial susceptibility patterns of thermophilic Campylobacter spp. from humans, pigs, cattle, and broilers in Denmark.

The MICs of 16 antimicrobial agents were determined for 202 Campylobacter jejuni isolates, 123 Campylobacter coli isolates, and 6 Campylobacter lari isolates from humans and food animals in Denmark. The C. jejuni isolates originated from humans (75), broilers (95), cattle (29), and pigs (3); the C. coli isolates originated from humans (7), broilers (17), and pigs (99); and the C. lari isolates originated from broilers (5) and cattle (1). All isolates were susceptible to apramycin, neomycin, and gentamicin. Only a few C. jejuni isolates were resistant to one or more antimicrobial agents. Resistance to tetracycline was more common among C. jejuni isolates from humans (11%) than among C. jejuni isolates from animals (0 to 2%). More resistance to streptomycin was found among C. jejuni isolates from cattle (10%) than among those from humans (4%) or broilers (1%). A greater proportion of C. coli than of C. jejuni isolates were resistant to the other antimicrobial agents tested. Isolates were in most cases either coresistant to tylosin, spiramycin, and erythromycin or susceptible to all three antibiotics. More macrolide-resistant isolates were observed among C. coli isolates from swine (79%) than among C. coli isolates from broilers (18%) and humans (14%). Twenty-four percent of C. coli isolates from pigs were resistant to enrofloxacin, whereas 29% of C. coli isolates from humans and none from broilers were resistant. More resistance to streptomycin was observed among C. coli isolates from swine (48%) than among C. coli isolates from broilers (6%) or humans (0%). The six C. lari isolates were susceptible to all antimicrobial agents except ampicillin and nalidixic acid. This study showed that antimicrobial resistance was found only at relatively low frequencies among C. jejuni and C. lari isolates. Among C. coli isolates, especially from swine, there was a high level of resistance to macrolides and streptomycin. Furthermore, this study showed differences in the resistance to antimicrobial agents among Campylobacter isolates of different origins.     

Prevalence of multiple antibiotic resistance in 443 Campylobacter spp. isolated from humans and animals

AIMS: In view of recent findings that a multidrug efflux pump CmeABC exists in Campylobacter jejuni, 391 C. jejuni and 52 Campylobacter coli of human and animal origin were examined for a multidrug resistance phenotype. MATERIALS AND METHODS: The MICs of ampicillin, chloramphenicol, ciprofloxacin, erythromycin, kanamycin, tetracycline, cetrimide, triclosan, acridine orange, paraquat and ethidium bromide were determined. Resistance to organic solvents and the effect of salicylate (known inducer of the marRAB operon in Escherichia coli and Salmonella) were also examined. RESULTS: Two C. coli and 13 C. jejuni isolates, mainly from pigs or poultry, were resistant to three or more antibiotics and 12 of these strains had reduced susceptibility to acridine orange and/or ethidium bromide. Strains (n = 20) that were less susceptible to acridine orange, ethidium bromide and triclosan were significantly more resistant (P < 0.05) to ampicillin, chloramphenicol, ciprofloxacin, erythromycin, nalidixic acid and tetracycline, with two- to four-fold increases in MIC values compared with strains (n = 20) most susceptible to acridine orange, ethidium bromide and triclosan. Growth of strains with 1 mM salicylate caused a small (up to two-fold) but statistically significant (P < or = 0.005) increase in the MICs of chloramphenicol, ciprofloxacin, erythromycin and tetracycline. CONCLUSIONS: These data indicate that multiple antibiotic resistant (MAR)-like Campylobacter strains occur and it may be postulated that these may overexpress cmeABC or another efflux system.     

Antimicrobial resistance in Campylobacter jejuni and Campylobacter coli strains isolated in 1991 and 2001-2002 from poultry and humans in Berlin, Germany

The susceptibilities of 430 Campylobacter jejuni strains and 79 C. coli strains to six antimicrobial agents were tested and analyzed. The two sets of strains originated from retail market chicken and turkey samples and from humans, respectively, in Berlin, Germany. Two groups of isolates, one dating from 1991 and the other dating from 2001-2002, were tested. Of the Campylobacter sp. isolates recovered from humans in 2001-2002, 45.1% were resistant to ciprofloxacin, 37.8% were resistant to tetracycline, 12.8% were resistant to ampicillin, and 50.0% were resistant to trimethoprim-sulfamethoxazole. All isolates were susceptible to gentamicin, while the overall rate of resistance to erythromycin was 6.1%. During the 10 years between the two sampling times, the rates of resistance to ciprofloxacin (P<0.001), ampicillin (P=0.035), and tetracycline (P=0.01) increased significantly among strains isolated from humans. Furthermore, among human C. coli strains the rate of resistance to erythromycin rose from 7.1% in 1991 to 29.4% in 2001-2002. In comparison, Campylobacter sp. isolates from poultry already had high rates of resistance in 1991. Different rates of resistance to tetracycline among isolates from chickens and turkeys suggested the development of resistance during antimicrobial treatment in food animals. Thus, discrepancies in the antimicrobial resistance rates among Campylobacter isolates originating from poultry and humans support the hypothesis that at least some of the resistant Campylobacter strains causing infection in humans come from sources other than poultry products.     

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。     

Antibiotic resistance in Campylobacter strains isolated from animals, foods, and humans in Spain in 1997-1998

Colonization by Campylobacter strains was investigated in human, broiler, and pig fecal samples from 1997-1998, as well as in foods of animal origin, and antibiotic susceptibility testing was carried out for these strains. Campylobacter strains were isolated in the foods of animal origin (55 of 101 samples; 54.4%), intestinal samples from broilers (85 of 105; 81%), and pigs (40 of 45; 88.9%). A total of 641 Campylobacter strains were isolated from 8,636 human fecal samples of clinical origin (7.4%). Campylobacter jejuni was the most frequently isolated species from broilers (81%) and humans (84%), and Campylobacter coli was most frequently isolated from pigs (100%). An extremely high frequency of ciprofloxacin resistance was detected among Campylobacter strains, particularly those isolated from broilers and pigs (99%), with a slightly lower result for humans (72%); cross-resistance with nalidixic acid was almost always observed. A higher frequency of resistance to erythromycin (81.1%), ampicillin (65.7%), gentamicin (22.2%), and amikacin (21.6%) was detected in C. coli strains isolated from pigs compared to those isolated from humans (34.5, 29.3, 8.6, and 0%, respectively). A low frequency of erythromycin resistance was found in C. jejuni or C. coli isolated from broilers. A greater resistance to ampicillin and gentamicin (47.4 and 11.9%, respectively) was detected in C. jejuni isolated from broilers than in human strains (38 and 0.4%, respectively). Beta-lactamase production was found in 81% of the Campylobacter strains tested, although 44% of them were characterized as ampicillin susceptible. The increasing rates of Campylobacter resistance make advisable a more conservative policy for the use of antibiotics in farm animals.     

Antimicrobial susceptibility of clinical isolates of non-jejuni/coli campylobacters and arcobacters from Belgium

OBJECTIVES: To determine the susceptibility of non-jejuni/coli campylobacters and arcobacters isolated from diarrhoeal stool specimens in Belgium. METHODS: The MICs were determined using Etest for six antimicrobial agents including ampicillin, erythromycin, nalidixic acid, ciprofloxacin, gentamicin and tetracycline for the most frequently isolated non-jejuni/coli campylobacter and arcobacter strains in two University Hospital laboratories between 1995 and 2005. RESULTS: In total, 85 Campylobacter upsaliensis, 20 Campylobacter concisus, 11 Campylobacter fetus, 61 Arcobacter butzleri and 10 Arcobacter cryaerophilus isolates were tested. Most C. upsaliensis strains were susceptible to ampicillin (100%), gentamicin (100%), ciprofloxacin (94.1%) and tetracycline (100%), whereas 11.8 and 12.9% were resistant to nalidixic acid and erythromycin, respectively. For A. butzleri, 78.7% of isolates were susceptible to ampicillin and erythromycin. Most A. butzleri isolates were susceptible to ciprofloxacin (96.7%), nalidixic acid (82.0%), gentamicin (100%) and tetracycline (100%). All C. concisus strains were fully susceptible to ampicillin and tetracycline, but 5% of them were resistant to gentamicin, ciprofloxacin and erythromycin. Nearly all C. fetus and A. cryaerophilus strains were susceptible to erythromycin but the results should be interpreted with caution since only a small number of strains were tested. CONCLUSIONS: Fluoroquinolones should be considered in the treatment of severe C. upsaliensis and A. butzleri infection. When clinically indicated, erythromycin remains the first choice for the treatment of intestinal campylobacteriosis caused by C. concisus and C. fetus.     

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.     

Comparison of the Etest and agar dilution for in vitro antimicrobial susceptibility testing of Campylobacter

The performance of the Etest and agar dilution for in vitro antimicrobial susceptibility of Campylobacter spp. was evaluated using a quality control strain Campylobactor jejuni ATCC 33560, and 81 C. jejuni and 54 Campylobacter coli isolates recovered from retail raw meats. Seven antimicrobial agents: chloramphenicol, ciprofloxacin, doxycycline, erythromycin, gentamicin, nalidixic acid and tetracycline, were tested using the two methods, whereas azithromycin was tested using the Etest only. The correlation between the Etest and agar dilution MICs varied greatly depending on the antimicrobial agents tested. The overall agreement of MICs (+/-1 log(2) dilution) between the two methods was 61.9%, ranging from 21.4% for nalidixic acid to 92.6% for gentamicin. MICs obtained using the Etest were generally lower than those by agar dilution regardless of the species of organism tested. MIC(50) and/or MIC(90) values were at least one dilution lower for the Etest than for agar dilution when testing chloramphenicol, ciprofloxacin, doxycycline, erythromycin and nalidixic acid. Based on the agar dilution MICs, the resistant rate of the 135 Campylobacter isolates was highest for tetracycline (82.2%), followed by doxycycline (78.5%), nalidixic acid (21.5%), ciprofloxacin (20.7%) and erythromycin (17.0%). None of the isolates demonstrated resistance to chloramphenicol or gentamicin. The study indicated that the Etest results were not in complete agreement with the agar dilution test. Although the Etest has been proven to be a satisfactory testing method, its use for Campylobacter susceptibility testing requires further standardization. The study also showed that C. jejuni and C. coli isolates resistant to antimicrobials used for treating campylobacteriosis were common in retail raw meats.     

Antibiotic resistance in Campylobacter jejuni and Campylobacter coli isolated from poultry in the South-East Queensland region

OBJECTIVES: The aim of this study was to determine the antimicrobial resistance patterns of 125 Campylobacter jejuni and 27 Campylobacter coli isolates from 39 Queensland broiler farms. METHODS: Two methods, a disc diffusion assay and an agar-based MIC assay, were used. The disc diffusion was performed and interpreted as previously described (Huysmans MB, Turnidge JD. Disc susceptibility testing for thermophilic campylobacters. Pathology 1997; 29: 209-16), whereas the MIC assay was performed according to CLSI (formerly NCCLS) methods and interpreted using DANMAP criteria. RESULTS: In both assays, no C. jejuni or C. coli isolates were resistant to ciprofloxacin or chloramphenicol, no C. coli were resistant to nalidixic acid, and no C. jejuni were resistant to erythromycin. In the MIC assay, no C. jejuni isolate was resistant to nalidixic acid, whereas three isolates (2.4%) were resistant in the disc assay. The highest levels of resistance of the C. jejuni isolates were recorded for tetracycline (19.2% by MIC and 18.4% by disc) and ampicillin (19.2% by MIC and 17.6% by disc). The C. coli isolates gave very similar results (tetracycline resistance 14.8% by both MIC and disc; ampicillin resistance 7.4% by MIC and 14.8% by disc). CONCLUSIONS: This work has shown that the majority of C. jejuni and C. coli isolates were susceptible to the six antibiotics tested by both disc diffusion and MIC methods. Disc diffusion represents a suitable alternative methodology to agar-based MIC methods for poultry Campylobacter isolates.     

A European survey of antimicrobial susceptibility among zoonotic and commensal bacteria isolated from food-producing animals

OBJECTIVE: To study antimicrobial resistance in zoonotic bacteria isolated from food animals in different countries using uniform methodology. METHODS: Samples were taken at slaughter from chickens, pigs and cattle in four EU countries per host. Escherichia coli (indicator organism; n = 2118), Salmonella spp. (n = 271) and Campylobacter spp. (n = 1325) were isolated in national laboratories and MICs tested in a central laboratory against, where appropriate, ampicillin, cefepime, cefotaxime, ciprofloxacin, chloramphenicol, erythromycin, gentamicin, nalidixic acid, streptomycin, tetracycline and trimethoprim/sulfamethoxazole. RESULTS: Isolation rates were high for E. coli, low for Salmonella and intermediate for Campylobacter. MIC results showed resistance prevalence varied among compounds, hosts and countries. For E. coli and Salmonella, resistance to newer compounds (cefepime, cefotaxime, ciprofloxacin) was absent or low, but to older compounds (except gentamicin), resistance was variable and higher. E. coli isolates from Sweden showed low resistance, whereas among isolates from Spain (pigs), resistance to ampicillin, chloramphenicol, streptomycin, tetracycline and trimethoprim/sulfamethoxazole was higher; the UK, France, the Netherlands, Germany, Italy and Denmark were intermediate. For Campylobacter spp. isolates from chickens, nalidixic acid and ciprofloxacin resistance was >30% in France and the Netherlands, >6% in the UK and zero in Sweden. Nalidixic acid resistance was high in cattle (20%-64%), whereas ciprofloxacin resistance was markedly lower in cattle, variable in pigs (3%-21%) and highest in Sweden. Generally, Campylobacter coli was more resistant than Campylobacter jejuni. CONCLUSION: Antimicrobial resistance among enteric organisms in food animals varied among countries, particularly for older antimicrobials, but resistance to newer compounds used to treat disease in humans was generally low.     

In vitro susceptibilities of aerotolerant Campylobacter isolates to 22 antimicrobial agents.

We evaluated the in vitro activities of 22 antimicrobial agents against 78 human and animal isolates belonging to two aerotolerant Campylobacter species, C. cryaerophila and C. butzleri, using a broth microdilution technique. An additional 10 antimicrobial agents were included at concentrations found in selective Campylobacter media. Strains of C. cryaerophila belonged to two DNA hybridization groups: DNA hybridization group 1A, which includes the type strain of C. cryaerophila, and DNA hybridization group 1B. The aminoglycosides, fluoroquinolones, and one tetracycline (minocycline) demonstrated the most activity against all DNA hybridization groups (C. cryaerophila DNA groups 1A and 1B and C. butzleri). Most isolates were resistant to cephalosporin antibiotics, with the exception of cefotaxime, and were variably susceptible to trimethoprim-sulfamethoxazole. C. cryaerophila DNA hybridization group 1A isolates were generally susceptible to the tetracyclines, chloramphenicol, nalidixic acid, azithromycin, erythromycin, and roxithromycin and moderately susceptible to clindamycin, trimethoprim-sulfamethoxazole, ampicillin, and ampicillin-sulbactam. The MICs of tetracyclines were higher for C. butzleri and C. cryaerophila DNA hybridization group 1B isolates than for C. cryaerophila DNA hybridization group 1A isolates, but most strains were still susceptible to doxycycline and tetracycline; all isolates were susceptible to minocycline. C. butzleri and C. cryaerophila DNA hybridization group 1B isolates were generally resistant to the macrolide antibiotics (including erythromycin), chloramphenicol, clindamycin, nalidixic acid, ampicillin, and trimethoprim-sulfamethoxazole. Differences in antimicrobial susceptibility between aerotolerant Campylobacter species and more common Campylobacter species, e.g., C. jejuni, suggest that different treatment strategies may be necessary. Strains of all three DNA hybridization groups of aerotolerant Campylobacter isolates were susceptible to colistin, polymyxin B, and rifampin at concentrations commonly used in selective media. These results suggest that primary isolation methods for Campylobacter species may need to be modified to include aerotolerant Campylobacter strains.     

Susceptibilities to 10 antimicrobial agents of 1,220 Campylobacter strains isolated from 1987 to 1993 from feces of pediatric patients.

We report the in vitro antibiotic susceptibility of 1,220 strains belonging to the thermotolerant Campylobacter species, isolated from the feces of pediatric patients with diarrhea in the period from 1987 to 1993. The strains were identified as 1,148 C. jejuni isolates and 72 C. coli isolates. The overall results show that the strains showed drug resistance as follows: 51.8% to ampicillin, 4.4% to clindamycin, 2.6% to chloramphenicol, 21.2% to tetracycline, and 1% to gentamicin. Twenty-one strains (1.7%) displayed resistance to the combination of amoxicillin-clavulanic acid, and 3.2% of the strains were resistant to erythromycin (MIC of > or = 4 micrograms/ml), with a notable difference according to the species under consideration. While C. jejuni remained stable at 0.9 to 4% resistance to erythromycin, for C. coli the percentages detected ranged from 0 to 33%, with overall rates of 2.5 and 15.2% for the two species, respectively. Resistance to nalidixic acid (MIC of > or = 32 micrograms/ml) was found in 27.2% of the strains (27.8% for C. jejuni and 18% for C. coli), and resistance to ciprofloxacin (MIC of > or = 4 micrograms/ml) was found in 24.2% of the strains for C. jejuni and 15.2% for C. coli). Cross-resistance between nalidixic acid and ciprofloxacin was found in 89.1% of the strains (type 1 mutants), while 10.9% were resistant to nalidixic acid but susceptible to ciprofloxacin (type 2 mutants).     

Antimicrobial sensitivity and plasmid-mediated tetracycline resistance in Campylobacter jejuni isolated in Bangladesh

The antimicrobial sensitivity of Campylobacter jejuni isolated in Bangladesh from patients with diarrhoea, asymptomatic carriers and domestic animals was performed. All isolates were sensitive to erythromycin, gentamicin, furazolidone and kanamycin. Seven percent isolates were resistant to tetracycline, 8% to nalidixic acid, 37% to ampicillin and 100% to sulfamethoxazole-trimethoprim and cephalothin. Tetracycline resistance was observed to be plasmid mediated. No plasmid band(s) coding for ampicillin, sulfamethoxazole-trimethoprim or cephalothin resistance were observed, possibly indicating chromosomally located resistance. No significant differences in the susceptibility patterns of C. jejuni isolated from the different sources was observed. However, 10 patients' isolates showed low molecular weight (2-3, 7 Mdaltons) plasmid band(s) which were completely absent in isolates from asymptomatic carriers and animals.     

Role of efflux pumps and topoisomerase mutations in fluoroquinolone resistance in Campylobacter jejuni and Campylobacter coli

Point mutations in the topoisomerase (DNA gyrase A) gene are known to be associated with fluoroquinolone resistance in Campylobacter. Recent studies have shown that an efflux pump encoded by cmeABC is also involved in decreased susceptibilities to fluoroquinolones, as well as other antimicrobials. Genome analysis suggests that Campylobacter jejuni contains at least nine other putative efflux pumps. Using insertional inactivation and site-directed mutagenesis, we investigated the potential contributions of these pumps to susceptibilities to chloramphenicol, ciprofloxacin, erythromycin, and tetracycline in C. jejuni and Campylobacter coli. Insertional inactivation of cmeB resulted in 4- to 256-fold decreases in the MICs of chloramphenicol, ciprofloxacin, erythromycin, and tetracycline, with erythromycin being the most significantly affected. In contrast, inactivation of all other putative efflux pumps had no effect on susceptibility to any of the four antimicrobials tested. Mutation of gyrA at codon 86 (Thr-Ile) caused 128- and 64-fold increases in the MICs of ciprofloxacin and nalidixic acid, respectively. The replacement of the mutated gyrA with a wild-type gyrA allele resulted in a 32-fold decrease in the ciprofloxacin MIC and no change in the nalidixic acid MIC. Our findings indicate that CmeABC is the only efflux pump among those tested that influences antimicrobial resistance in Campylobacter and that a point mutation (Thr-86-Ile) in gyrA directly causes fluoroquinolone resistance in Campylobacter. These two mechanisms work synergistically in acquiring and maintaining fluoroquinolone resistance in Campylobacter species.     

Antimicrobial resistance of Campylobacter jejuni and Campylobacter coli with special reference to plasmid profiles of Japanese clinical isolates.

A total of 111 clinical isolates of Campylobacter jejuni and 10 clinical isolates of Campylobacter coli were characterized by their susceptibility to nine antimicrobial agents and by their plasmid profiles on agarose gel electrophoresis. All of the C. jejuni isolates were susceptible to chloramphenicol, ciprofloxacin, erythromycin, kanamycin, and nalidixic acid, but 55% were tetracycline resistant. In the 10 C. coli isolates, a high prevalence of multiple-antibiotic resistance was noted. Plasmids were found in 82% of the tetracycline-resistant and 15% of the tetracycline-susceptible C. jejuni isolates. Tetracycline resistance in six randomly selected C. jejuni isolates, which contained 50- or 135-kilobase (kb) plasmids, was transferred by conjugation to a Campylobacter fetus subsp. fetus recipient with recovery of a 50- or a 45-kb plasmid from transconjugants. From one multiple-antibiotic-resistant C. coli isolate, resistance to tetracycline, kanamycin, and chloramphenicol was transferred concomitantly with a 58-kb plasmid, pNR9589. Nonconjugative 98-kb plasmids, pNR9131 and pNR9581, from C. coli isolates with resistance to tetracycline, kanamycin, and erythromycin were shown by cloning experiments to code for at least kanamycin resistance. Restriction digests revealed that 50-kb plasmids from tetracycline-resistant C. jejuni isolates were identical, although plasmids from multiple-antibiotic-resistant C. coli isolates shared partial DNA homology to each other. Cloning of the kanamycin and chloramphenicol resistance genes of pNR9589 into Escherichia coli showed that the two genes are closely linked or clustered. Double-digestion analysis of the fragments encoding the kanamycin resistance of pNR9131, pNR9581, and pNR9589 showed that these three plasmids contain a common fragment related to kanamycin resistance.     

Activity of antibiotics used in human medicine for Campylobacter jejuni isolated from farm animals and their environment in Lancashire, UK

A retrospective study of 96 Campylobacter jejuni isolated from farm animals and the environment showed that most were less susceptible than the NCTC type strain to nalidixic acid (MICs 4-32 mg/L), ciprofloxacin (MICs 1-2 mg/L) and erythromycin (MICs 16-64 mg/L), but had similar susceptibility to tetracycline (MICs 4-8 mg/L) and kanamycin (MICs 4-8 mg/L). None had the high MICs of ciprofloxacin (>32 mg/L) or erythromycin (1024 mg/L) typically associated with clinical resistance in this species. Some farms used antimicrobial agents, but there was no obvious association between the use of agents and the susceptibility of the isolates.     

Antimicrobial susceptibility patterns of Campylobacter jejuni strains isolated from hospitalized children in Athens,Greece

The antimicrobial susceptibility of 129 Campylobacter jejuni strains, isolated from hospitalized children with gastroenteritis, to five antimicrobials, including nalidixic acid, ciprofloxacin, erythromycin, ampicillin and co-amoxiclav, was determined. Isolates belonged to two time periods: group A contained strains isolated in 1987-1988; and group B 1998-2000. Antimicrobial susceptibility patterns differed significantly between the two groups with respect to quinolones, with an increase in the percentage of resistant strains in group B (30.6% versus 0% in group A), whereas erythromycin, ampicillin and co-amoxiclav were effective drugs in both groups.     

Antimicrobial resistance of Campylobacter jejuni subsp. jejuni strains isolated from humans in 1998 to 2001 in Montréal,Canada

The rates of resistance of 51 to 72 human strains of Campylobacter jejuni subsp. jejuni isolated annually from 1998 to 2001 in Montréal, Québec, Canada, varied from 1 to 12% for erythromycin, 43 to 68% for tetracycline, and 10 to 47% for ciprofloxacin. In the last years of the study, there was a significant increase in the rate of resistance to ciprofloxacin (P = 0.00003) but not in the rate of resistance to erythromycin (P = 0.056) or tetracycline (P = 0.095) compared to the rate obtained in the first years. All 51 C. jejuni strains isolated in 2001 were susceptible to gentamicin, amoxicillin-clavulanic acid, imipenem, and meropenem. From 1999 to 2001, 74 strains of C. jejuni acquired abroad were significantly more resistant to ciprofloxacin than 109 strains of C. jejuni acquired locally (66 versus 9%, P < 0.00001) but were not significantly more resistant to erythromycin (1 versus 6%, P = 0.15) or to tetracycline (55 versus 58%, P = 0.87).     

Antibiotic resistance of Campylobacter jejuni and Campylobacter coli clinical isolates from Poland

We tested 102 Campylobacter jejuni and 6 Campylobacter coli clinical isolates from Poland. All were susceptible to erythromycin. Among the tested C. jejuni isolates 55.9% and 13.7% were resistant to ciprofloxacin and tetracycline, respectively. Replacement of Thr86 with Ile in GyrA and a plasmid-borne tet(O) gene were the main resistance mechanisms for fluoroquinolones and tetracycline, respectively.     

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.