Antimicrobial susceptibilities of Campylobacter sp strains isolated from humans in 2005 to 2006 in Bielsko-Biala Region, Poland

Campylobacter jejuni and Campylobacter coli are frequent causes of bacterial gastroeneritis in humans worldwide. Campylobacteriois is usually a self-limiting disease and therapy with antibiotics is required in severe clinical infections. The objective [corrected] of this study was to determine the antibiotic resistance of C. jejuni and C. coli isolated from humans with diarrhea during 2005-2006 in Bielsko-Biala region in Poland. The MICs of ciprofloxacin, tetracycline, erythromycin, gentamicin and ampicillin were determined by the E-test method. It was observed that 23 % and 6% C. jejuni isolates were resistant to two and three antibiotics, respectively. All isolates of Campylobacter sp. were sensitive to erythromycin and gentamicin. From the 69 C. jejuni strains 58% were resistant to ciprofloxacin, 23% to tetracycline and 17% to ampicillin. From the 8 C. coli strains all were resistant to ciprofloxacin, 62,5% to ampicillin and 12,5% to tetracycline.     

139株空肠弯曲菌耐药性分析

空肠弯曲菌(Campylobacter jejuni)是最常见的食源性病原菌之一。本研究采用微量肉汤稀释法对分离得到的139株空肠弯曲菌(117株为禽源样本分离株,22株为人源样本分离株)进行耐药性检测。通过对最小抑菌浓度(MIC)的判定结果得出:120株(86. 33%)空肠弯曲菌分离株对6类9组临床常用的抗生素表现出不同程度的耐药,其中禽源空肠弯曲菌耐药率为83. 76%,22株人源空肠弯曲菌均表现出耐药性。对喹诺酮类抗生素表现出高度耐药(环丙沙星80. 58%,萘啶酸77. 70%);对四环素类表现为中等耐药(四环素53. 24%);对部分大环内酯类、氨基糖苷类、林可酰胺类表现为低耐药(庆大霉素7. 19%,阿奇霉素5. 76%,克林霉素6. 47%);对酰胺醇类、部分大环内酯类表现为敏感(氟苯尼考0%,红霉素0%、泰利霉素0%)。139株空肠弯曲菌共产生14种耐药谱型,以TET-CIP-NAL谱型最多,占比38. 13%,耐三重及以上抗生素的多重耐药菌株占比53. 24%。禽源菌株中多重耐药占比46. 15%,人源菌株中多重耐药占比90. 91%。研究结果显示空肠弯曲菌耐药现状不容乐观,尤其对喹诺酮类与四环素类抗生素耐药性较为突出,且过半数菌株为多重耐药。本研究为食源性空肠弯曲菌的防控及临床用药提供参考。     

Effect of conventional and organic production practices on the prevalence and antimicrobial resistance of Campylobacter spp. in poultry

Intestinal tracts of broilers and turkeys from 10 conventional broiler farms and 10 conventional turkey farms, where antimicrobials were routinely used, and from 5 organic broiler farms and 5 organic turkey farms, where antimicrobials had never been used, were collected and cultured for Campylobacter species. A total of 694 Campylobacter isolates from the conventional and organic poultry operations were tested for antimicrobial resistance to nine antimicrobial agents by the agar dilution method. Although Campylobacter species were highly prevalent in both the conventional and organic poultry operations, the antimicrobial resistance rates were significantly different between the organic operations and the conventional operations. Less than 2% of Campylobacter strains isolated from organically raised poultry were resistant to fluoroquinolones, while 46% and 67% of Campylobacter isolates from conventionally raised broilers and conventionally raised turkeys, respectively, were resistant to these antimicrobials. In addition, a high frequency of resistance to erythromycin (80%), clindamycin (64%), kanamycin (76%), and ampicillin (31%) was observed among Campylobacter isolates from conventionally raised turkeys. None of the Campylobacter isolates obtained in this study was resistant to gentamicin, while a large number of the isolates from both conventional and organic poultry operations were resistant to tetracycline. Multidrug resistance was observed mainly among Campylobacter strains isolated from the conventional turkey operation (81%). Findings from this study clearly indicate the influence of conventional and organic poultry production practices on antimicrobial resistance of Campylobacter on poultry farms.     

Prevalence and antimicrobial resistance of Campylobacter in US dairy cattle

AIMS: To obtain an overview of the prevalence and antimicrobial resistance of Campylobacter in faeces of US dairy cows in 2002. METHODS AND RESULTS: Faeces from 1435 cows, representing 96 dairy operations in 21 US states, were collected for the culture of Campylobacter. A total of 735 Campylobacter strains were isolated (51.2% positive samples) with 94 operations positive (97.9%) for Campylobacter. From this collection, 532 isolates (473 Campylobacter jejuni and 59 Campylobacter coli) were randomly selected for susceptibility testing to eight antimicrobials: azithromycin, chloramphenicol, ciprofloxacin, clindamycin, erythromycin, gentamicin, nalidixic acid and tetracycline. The C. jejuni isolates exhibited resistance to tetracycline (47.4%), nalidixic acid (4.0%) and ciprofloxacin (2.5%), while the C. coli strains exhibited some resistance to all antimicrobials except chloramphenicol and ciprofloxacin. Only 3.6% of the C. jejuni isolates were resistant to two or more antimicrobials but 20.3% of the C. coli strains were multiresistant. CONCLUSIONS: On most operations, at least one cow was positive for Campylobacter and more than half of the cows sampled were shedding Campylobacter. The C. coli isolates had significantly higher levels of resistance to macrolides and to tetracycline compared with the C. jejuni strains, but were susceptible to ciprofloxacin. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrated a high prevalence of Campylobacter on US dairy operations; however, US dairy cattle have not been recognized as a major source of human infection compared with poultry. Campylobacter coli appears to develop antimicrobial resistance more readily than C. jejuni from the same environment.     

Effects of orally administered tetracycline on the intestinal community structure of chickens and on tet determinant carriage by commensal bacteria and Campylobacter jejuni

There is a growing concern that antibiotic usage in animal production has selected for resistant food-borne bacteria. Since tetracyclines are common therapeutic antibiotics used in poultry production, we sought to evaluate the effects of oral administration on the resistance of poultry commensal bacteria and the intestinal bacterial community structure. The diversity indices calculated from terminal restriction fragment length polymorphism (T-RFLP) analysis of 16S rRNA amplicons did not indicate significant changes in the cecal bacterial community in response to oxytetracycline. To evaluate its effects on cultivable commensals, Enterococcus spp., Escherichia coli, and Campylobacter spp. were isolated from the cecal droppings of broiler chickens. Enterococcus spp. and E. coli expressed tetracycline MICs of >8 microg/ml and harbored a variety of tet resistance determinants regardless of the tetracycline exposure history of the birds. The enterococcal isolates possessed tetM (61%), tetL (25.4%), and tetK (1.3%), as well as tetO (52.5%), the determinant known to confer a tetracycline resistance phenotype in Campylobacter jejuni. E. coli isolates harbored tetA (32.2%) or tetB (30.5%). Tetracycline MICs remained at <2 microg/ml for Campylobacter isolates before and after tetracycline treatment of the chickens, even though isolates expressing MICs of >16 mug/ml were commonly cultured from flocks that did not receive oxytetracycline. The results imply that complex ecological and genetic factors contribute to the prevalence of antibiotic resistance arising from resistance gene transfer in the production environment.     

The genetics of tetracycline resistance in Staphylococcus aureus.

Eighty-one strains ofStaphylococcus aureus that appeared to be tetracycline resistant on the basis of a preliminary disc-diffusion test were examined fro resistance to tetracycline and to the semi-synthetic tetracycline, minocycline. Minimum inhibitory concentration (m.i.c.) values for both drugs were determined after induction of the strains by growth for 2 h in sub-inhibitory concentrations fo tetracycline. Forty-seven strain (58 percent) had m.i.c. values for minocycline of I2.5 MUg/ml or greater, and were considered to be minocycline resistant. An additional ten strains had m.i.c.r greater, and were considered to be minocycline resistant. An additional ten strains had m.i.c.values for minocycline of 3.I25 to 6-25 MUg/ml and were classified as low-level resistant strain. It appears, therefore, that a faily high proportion fo tetracycline-resistant strains isolated at the present time are resistant of concentrations of minocycline unattainbale in vivo with the recommended dosage forthis antibiotic (Fishk & Tunevall, 1969). Transductioal analysis of the genetic determinantswo types of resistance to high concentrations of tetracycline. Strains in the first categroy (A)were inducibly resistant to tetracycline but sensitive to minocycline; in these strains the resistance determinant was plasmid-borne. Strains in the second categroy (B) were resistant to both tetracycline and minocycline and had low induction ratios for tetracycline resistance; the genetic determinant for resistance in these strains was chromosomal. In addition, certain strains incategroy A were found to carry a chromosomal gene controlling low-level resistance to tetracycline and minocycline. This low-level resistance to tetracycline was masked in the presence of the tetracycline plasmide but could be demonstrated after loss of the plasmid. The results suggest that more than one mechanism of resistance to tetracyclines may exist in staphylococci.     

Effects of subtherapeutic administration of antimicrobial agents to beef cattle on the prevalence of antimicrobial resistance in Campylobacter jejuni and Campylobacter hyointestinalis

The influence of antimicrobial agents on the development of antimicrobial resistance (AMR) in Campylobacter isolates recovered from 300 beef cattle maintained in an experimental feedlot was monitored over a 315-day period (11 sample times). Groups of calves were assigned to one of the following antimicrobial treatments: chlortetracycline and sulfamethazine (CS), chlortetracycline alone (Ct), virginiamycin, monensin, tylosin phosphate, and no antimicrobial agent (i.e., control treatment). In total, 3,283 fecal samples were processed for campylobacters over the course of the experiment. Of the 2,052 bacterial isolates recovered, 92% were Campylobacter (1,518 were Campylobacter hyointestinalis and 380 were C. jejuni). None of the antimicrobial treatments decreased the isolation frequency of C. jejuni relative to the control treatment. In contrast, C. hyointestinalis was isolated less frequently from animals treated with CS and to a lesser extent from animals treated with Ct. The majority (> or =94%) of C. jejuni isolates were sensitive to ampicillin, erythromycin, and ciprofloxacin, but more isolates with resistance to tetracycline were recovered from animals fed Ct. All of the 1,500 isolates of C. hyointestinalis examined were sensitive to ciprofloxacin. In contrast, 11%, 10%, and 1% of these isolates were resistant to tetracycline, erythromycin, and ampicillin, respectively. The number of animals from which C. hyointestinalis isolates with resistance to erythromycin and tetracycline were recovered differed among the antimicrobial treatments. Only Ct administration increased the carriage rates of erythromycin-resistant isolates of C. hyointestinalis, and the inclusion of CS in the diet increased the number of animals from which tetracycline-resistant isolates were recovered. The majority of C. hyointestinalis isolates with resistance to tetracycline were obtained from cohorts within a single pen, and most of these isolates were recovered from cattle during feeding of a forage-based diet as opposed to a grain-based diet. The findings of this study show that the subtherapeutic administration of tetracycline, alone and in combination with sulfamethazine, to feedlot cattle can select for the carriage of resistant strains of Campylobacter species. Considering the widespread use of in-feed antimicrobial agents and the high frequency of beef cattle that shed campylobacters, the development of AMR should be monitored as part of an on-going surveillance program.     

Antimicrobial resistance patterns of Campylobacter from feedlot cattle*

AIMS: This study examined 448 Campylobacter strains isolated in 1999 and 2000 from US feedlot cattle for resistance to 12 antimicrobials. METHODS AND RESULTS: Isolates were tested for antimicrobial susceptibility using the E-test method. Approximately 60% (n = 267) were resistant to one or more antimicrobials, and 19.6% (n = 88) were resistant to two or more antimicrobials. Of the Campylobacter jejuni isolates, 49.1% (n = 187) were resistant to tetracycline, 10.2% (n = 39) were resistant to nalidixic acid, 8.4% were resistant to trimethoprim/sulfamethoxazole, and 1.8% (n = 7) were resistant to ciprofloxacin. Resistance to any of the other eight antimicrobials was 1.3% or less, but 14.4% (n = 55) were resistant to two or more antimicrobials. In the Campylobacter coli group, 65.7% (n = 44) were resistant to tetracycline, 52.2% (n = 35) were resistant to trimethoprim/sulfamethoxazole, 22.4% (n = 15) were resistant to nalidixic acid, and 9.0% (n = 6) were resistant to ciprofloxacin. Resistance to any of the remaining eight antimicrobials was 3.0% or less, although 49.3% (n = 33) were resistant to two or more antimicrobials. CONCLUSIONS: Although antimicrobials are widely used in US feedlot cattle production, our results demonstrate generally low levels of resistance to a broad range of commonly used antimicrobials relative to other recent studies. SIGNIFICANCE AND IMPACT OF THE STUDY: Resistance data on Campylobacter isolated from this major US livestock commodity is lacking. This overview enhances current knowledge and provides a basis for further studies.     

Evidence for natural horizontal transfer of tetO gene between Campylobacter jejuni strains in chickens

AIMS: The transfer of tetO gene conferring resistance to tetracycline was studied between Campylobacter jejuni strains, in the digestive tract of chickens. METHODS AND RESULTS: In vitro conjugation experiments were first performed in order to select donor/recipient couples for further in vivo assay. Then, chickens were inoculated with a donor/recipient couple of C. jejuni strains displaying spontaneous in vitro tetracycline resistance gene transfer. The donor was a tetracycline-resistant ampicillin-susceptible strain, and the recipient was a tetracycline-susceptible ampicillin-resistant strain. Chicken droppings were streaked on antimicrobial selective media and bi-resistant Campylobacter isolates were further characterized according to their donor or recipient flaA gene RFLP profile. The acquisition of tetracycline-resistance gene by the recipient C. jejuni strain from the donor C. jejuni strain was confirmed by tetO PCR. CONCLUSIONS: The study showed that transfer of tetO gene occurs rapidly and without antimicrobial selection pressure between C. jejuni strains in the digestive tract of chickens. SIGNIFICANCE AND IMPACT OF THE STUDY: The rapid and spontaneous transfer of tetO gene may explain the high prevalence of tetracycline resistance in chicken Campylobacter strains.     

Comparison of prevalence and antimicrobial susceptibilities of Campylobacter spp. isolates from organic and conventional dairy herds in Wisconsin

The prevalence and antimicrobial susceptibilities of Campylobacter spp. isolates from bovine feces were compared between organic and conventional dairy herds. Thirty organic dairy herds, where antimicrobials are rarely used for calves and never used for cows, were compared with 30 neighboring conventional dairy farms, where antimicrobials were routinely used for animals for all ages. Fecal specimens from 10 cows and 10 calves on 120 farm visits yielded 332 Campylobacter isolates. The prevalence of Campylobacter spp. in organic and conventional farms was 26.7 and 29.1%, and the prevalence was not statistically different between the two types of farms. Campylobacter prevalence was significantly higher in March than in September, higher in calves than in cows, and higher in smaller farms than in large farms. The rates of retained placenta, pneumonia, mastitis, and abortion were associated with the proportion of Campylobacter isolation from fecal samples. The gradient disk diffusion MIC method (Etest) was used for testing susceptibility to four antimicrobial agents: ciprofloxacin, gentamicin, erythromycin, and tetracycline. Two isolates were resistant to ciprofloxacin, and none of isolates was resistant to gentamicin or erythromycin. Resistance to tetracycline was 45% (148 of 332 isolates). Tetracycline resistance was found more frequently in calves than in cows (P = 0.042), but no difference was observed between organic and conventional farms. When we used Campylobacter spp. as indicator bacteria, we saw no evidence that restriction of antimicrobial use on dairy farms was associated with prevalence of resistance to ciprofloxacin, gentamicin, erythromycin, and tetracycline.     

Antimicrobial resistance and genomic screening of clinical isolates of thermophilic Campylobacter spp. from south-east Queensland,Australia

AIM: To screen 90 clinical isolates of thermophilic Campylobacter species for putative resistance to ampicillin, erythromycin and tetracycline and perform numerical analysis to determine isolate relatedness. METHODS AND RESULTS: Disc diffusion, E-test MIC and agar dilution methods were performed. Disc diffusion testing showed 87 (97%) isolates appeared resistant to ampicillin at 10 microg; 14 (16%) resistant to tetracycline at 30 microg; and three (3.4%) resistant to erythromycin at 15 microg. E-test MICs showed a range of 0.5 to >256 mg l(-1) for ampicillin; 16 to >256 mg l(-1) for tetracycline; and >256 mg l(-1) for erythromycin. E-test showed 68% correlation (+/-1 log2 dilution) with agar dilution for ampicillin, 100% for erythromycin and 64% for tetracycline. Disc diffusion testing showed 100% correlation with agar dilution for erythromycin and tetracycline, and 77% for ampicillin. Numerical analyses of restriction endonuclease (RE) fragment profiles suggested a high level of isolate variation. CONCLUSION: The incidence of resistance of thermophilic Campylobacter spp. to erythromycin and tetracycline is low in south-east Queensland. SIGNIFICANCE AND IMPACT OF THE STUDY: Disc diffusion susceptibility testing may be used to screen thermophilic Campylobacter spp. for putative resistance to erythromycin and tetracycline. Agar dilution should be used to determine ampicillin susceptibility.     

Incidence of antibiotic resistance and characterization of plasmids in Campylobacter jejuni strains isolated from clinical sources in Alberta, Canada

Antibiotic susceptibilities of 382 strains of Campylobacter jejuni isolated in Alberta, Canada, in 1980 and 1981 were determined. Although none were resistant to erythromycin or gentamicin, 5.4 and 22% of strains were resistant to ampicillin in 1980 and 1981, respectively. Tetracycline resistance was noted in 6.8% of strains in 1980 and in 8.6% in 1981. Moreover, resistance to high-level tetracycline (32-128 micrograms/mL) was always mediated by a plasmid of 45-50 kilobases. Three transmissible plasmids from the Alberta strains were compared with the prototype plasmid pMAK175 by restriction enzyme analysis and some minor differences in restriction sites were noted between pMAK175 and pUA183. The two other plasmids pUA142 and pUA143 were 4 kilobases larger than pMAK175 and contained additional restriction sites. However, in all plasmids examined, the HincII and AccI fragments where the tetracycline-resistance determinant was located were shown to be conserved.     

Antimicrobial resistance profiling and DNA Amplification Fingerprinting (DAF) of thermophilic Campylobacter spp. in human, poultry and porcine samples from the Cork region of Ireland

Antimicrobial resistance (R) typing and DNA Amplification Fingerprinting (DAF) of a random collection of 84 Irish thermophilic Campylobacter isolates is described. The collection included human, veterinary (porcine) and poultry isolates cultured between 1996 and 1998 in the Cork region of Ireland. Biochemical and molecular methods were used to identify Campylobacter jejuni and Camp. coli. Many of these isolates were simultaneously resistant to several common antimicrobial agents. In particular, resistance to ampicillin, spectinomycin, sulphafurazole and tetracycline was common. A total of 74 DAF profiles was identified among the study collection, showing a high degree of diversity. Dendrogram analysis of the DNA patterns identified three main clusters at the 50% similarity level, which included two clusters of Camp. coli and a third containing a mixture of Camp. jejuni and Camp. coli.     

Tigecicline susceptibilities of tetracycline-resistant Campylobacter jejuni clinical strains isolated in Poland

Campylobacteriosis is a significant public health problem in many developed countries. Campylobacter jejuni is one of the leading causes of food-borne gastroenteritis and enteritis in humans. Treatment of campylobacteriosis is required in severe clinical infections, extraintestinal infections and in immunocompromised patients. Erythromycin is the proposed drug of choice for the treatment of Campylobacter infections. However, tetracycline and fluoroquinolones (ciprofloxacin) are also clinically effective agents for treating infections caused by Campylobacter spp. High prevalence of C. jejuni resistant to fluoroquinolone and tetracycline have been recently reported in many countries. In human medicine new agents for the treatment of many serious infections are acutely needed in hospital practice. Tigecycline is a member of a new group of antibiotics--the glycylcyclines with an expanded microbiological spectrum. In our study we will determine the susceptibility of polish, resistant to tetracycline clinical C. jejuni isolates to tigecycline. All 94 tetracycline-resistant C. jejuni strains, with MICs between 8 and 256 mg/l, isolated between 2007 and 2008 were susceptible to tigecycline, with MICs 0.06 mg/1. Tigecycline may has potential therapeutic role in the treatment of serious Campylobacter infections.     

Antimicrobial resistance of Campylobacter jejuni and Campylobacter coli isolates from broiler chickens isolated at an Irish poultry processing plant

AIMS: The antibiotic susceptibility of Campylobacter jejuni and Campylobacter coli isolates from broiler chickens were determined in order to evaluate the level of antibiotic resistance of Campylobacter species in the Irish poultry industry. METHODS AND RESULTS: Seventy-eight Camp. jejuni and 22 Camp. coli strains were examined for susceptibility to eight antibiotics using the disc diffusion assay. The highest level of resistance of the Camp. jejuni isolates was recorded to ampicillin (35.9%), followed by 20.5% to tetracycline, 20.5% to naladixic acid, 17.9% to ciprofloxacin, 10.2% to erythromycin, 2.5% to streptomycin and 1.2% to kanamycin. Multidrug resistance to two or more antibiotics was seen for 30.7% of Camp. jejuni strains. Resistance of the Camp. coli isolates was shown to ampicillin (9%) and tetracycline (18.2%). CONCLUSIONS: The majority of Camp. jejuni strains were susceptible to antibiotics commonly used for human therapy. Camp. coli strains showed very low resistance levels and were susceptible to six of the eight antimicrobial agents studied. SIGNIFICANCE AND IMPACT OF THE STUDY: Levels of Camp. jejuni and Camp. coli antimicrobial resistance in Irish poultry production was assessed to determine the current situation in Ireland. The prevalence of antibiotic resistance of Campylobacter strains isolated from broiler chickens was low.     

Factors affecting the pressure resistance of some Campylobacter species

AIMS: To compare pressure resistance between strains of Campylobacter jejuni, Campylobacter coli, Campylobacter lari and Campylobacter fetus, and to investigate the effect of suspending medium on pressure resistance of sensitive and more resistant strains. METHODS AND RESULTS: Six strains of C. jejuni and four each of C. coli, C. lari and C. fetus were pressure treated for 10 min at 200 and 300 MPa. Individual strains varied widely in pressure resistance but there were no significant differences between the species C. jejuni, C. coli and C. lari. Campylobacter fetus was significantly more pressure sensitive than the other three species. The pressure resistance of C. jejuni cultures reached a maximum at 16-18 h on entry into stationary phase then declined to a minimum at 75 h before increasing once more. Milk was more baroprotective than water, broth or chicken slurry but did not prevent inactivation even of a resistant strain at 400 MPa. CONCLUSIONS: Pressure resistance varies considerably between species of Campylobacter and among strains within a species, and survival after a pressure challenge will be markedly influenced by culture age and food matrix. SIGNIFICANCE AND IMPACT OF THE STUDY: Despite the strain variation in pressure resistance and protective effects of food, Campylobacter sp. do not present a particular problem for pressure processing.     

Antibiotic resistance of Shigella in different regions of the USSR]

Shigella were most sensitive to polymyxin ceporin, ampicillin, neomycin and furazolidone and resistant to chloramphenicol, tetracycline and streptomycin. Shigella resistant simultaneously to two or three drugs mainly to tetracycline + chloramphenicol, tetracycline + streptomycin and tetracycline + chloramphenicol + streptomycin were most frequent. The frequency of the Shigella strains carrying R-plasmids increased from 28 per cent in 1969--1970 to 72.6 per cent in 1977. The Shigella strains isolated during the dysentery outbreak in 1973--1977 carried the R-factor controlling resistance to tetracycline + chloramphenicol, tetracycline + chloramphenicol + streptomycin, tetracycline + chloramphenicol + streptomycin + neomycin. Interaction between separate biochemical types, colicinogenicity and drug resistance classes was found in the Shigella isolates. The data on the effect of antibiotic (tetracyclines) intensive use in stock-raising defining wide spread of the R-plasmids controlling resistance to these drugs were obtained.     

Cloning of tetracycline-resistance genes from various strains of Clostridium perfringens and expression in Escherichia coli.

One hundred strains of Clostridium perfringens and 52 strains of other clostridia of human and animal origins were screened for tetracycline resistance. Fifty-six strains were resistant to tetracycline in the C. perfringens group. Ten strains were selected for their high level of resistance. In all of them, the tetracycline-resistance genes were found to be residing in large plasmids of about 50 kb, all showing homologies. Several tetracycline-resistance genes from plasmids of various strains of C. perfringens were cloned in plasmid pUC19 and the resistance was expressed in Escherichia coli. Hybridization analysis showed these genes to be homologous among themselves and also to tetP gene from the PCW3-type plasmid.     

Antimicrobial susceptibility of Campylobacter jejuni subsp. jejuni assessed by E-test and double dilution agar method in Southern Chile

The susceptibility patterns of 108 Campylobacter jejuni subsp. jejuni clinical strains, to six antimicrobial agents was determined by using the E-test and the double dilution agar methods. Using both methods, no strain was found to be resistant to ciprofloxacin, erythromycin and gentamicin, but two (1.8%) were resistant to tetracycline and all to aztreonam. Seven (6.5%) strains were resistant to ampicillin by the E-test and five (4.6%) by the double dilution agar method and by both methods. No great discrepancies were observed between both methods.