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。     

Characteristic of clinical fluoroquinolone resistant isolates E. faecalis

In presented study we have characterized phenotype of clinical E. faecalis strains, fluoroquinolone susceptibility and the presence of two potential virulence factors--hemolysin/cytolysin and gelatinase. Eighty three of E. faecalis strains were isolated from clinical samples from patients of five Warsaw hospitals. Susceptibility to 18 antibiotics was assessed by the disk diffusion method (ace. NCCLS). The MIC of ciprofloxacin was determineted by agar dilution method and the MIC of sparfloxacin and moxifloxacin by the E-test (AB BIODISK). Hemolysin production was evaluated on Columbia agar medium supplemented with 5% horse blood. Gelatinase production was determinated by using two different methods: I - on the Todd-Hewitt agar containing gelatin (30 g/l) and II--on the trypticase soy agar supplemented with 1,5% skim milk. Fourty nine (59%) of the 83 isolates E. faecalis were ciprofloxacin resistant and 14 (16,9%) were ciprofloxacin intermediate. The majority of E. faecalis strains (57,8%) were higly resistant to ciprofloxacin (MIC > or = 32 microg/ml). All of ciprofloxacin resistant E. faecalis isolates were cross-resistant to the other fluoroquinolones, as well. Production of hemolysin was more frequent among ciprofloxacin resistant E. faecalis strains. The dependence between gelatinase production and fluoroquinolone:resistance was not observed. Both investigated methods of gelatinase activity detection gave the same results and can be used exchangeably. Hemolytic strains were more frequently isolated from urine (47,8%), however gelatinase producing strains were more frequently isolated from wounds (31,6%).     

The isolation and characterization of Campylobacter jejuni subsp. jejuni from domestic geese (Anser anser)

AIMS: The objectives of this study were to determine the presence of thermophilic Campylobacter spp. in free range domestic geese, and to characterize isolated strains using phenotyping criteria and SDS-PAGE of whole-cell proteins. METHODS AND RESULTS: Forty cloacal swabs from two different flocks of domestic geese were examined. All Camp. jejuni strains isolated from geese were biotyped using the Lior biotyping scheme. Twelve Camp. jejuni isolates were also tested for their susceptibility to 17 different antibacterial agents by a disc diffusion METHOD: Fourteen of the isolates were also subjected to SDS-PAGE. All of the geese examined were found to harbour Camp. jejuni. Six geese carried more than one species of Campylobacter. All strains examined were susceptible to various antibiotics but resistant to penicillin G and cephalothin. Eleven strains (92%) were resistant to sodium cefuroxime, and eight (67%) were resistant to cloxacillin, ampicillin and colistin sulphate. Three strains (25%) were resistant to tetracycline, and one strain was resistant to sulfamethoxazole/trimethoprim and kanamycin. Nine strains were subtyped as Camp. jejuni subsp. jejuni biotype II and the remaining ones as biotype I. There were 96% and 100% similarities between all the strains examined by SDS-PAGE. CONCLUSION: This study showed that Camp. jejuni were common in the intestinal tract of domestic geese. SIGNIFICANCE AND IMPACT OF THE STUDY: Geese should be considered as potential reservoirs for human and animal campylobacteriosis. The antibiotic resistance data from this study also showed that fluoroquinolone resistance, which appears to be a problem in poultry isolates in some countries, is not yet a problem in these geese.     

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.     

Survival of Campylobacter jejuni strains of different origin in drinking water

AIMS: The aim of the study was to measure the survival of 19 Campylobacter jejuni strains of different origins, including two reference strains, four poultry-derived isolates, nine human isolates and four water isolates, in sterilized drinking water. METHODS AND RESULTS: Pure cultures of 19 C. jejuni strains were inoculated in sterile drinking water and incubated at 4 degrees C for 64 days. Survival was determined by culturability on both selective (Karmali agar) and non-selective [Columbia blood agar (CBA)] media. Culturability was shown to be strain and origin-dependent. Campylobacter jejuni showed prolonged survival on a non-selective than on a selective medium. CONCLUSIONS: The origin of the strain is a determining factor for the survival of C. jejuni in drinking water at 4 degrees C. Poultry isolates showed a prolonged survival, which could be an indication that these strains could play an important role in the transmission of campylobacteriosis through water. In addition, culture conditions are an important factor for evaluating the survival of C. jejuni in drinking water at 4 degrees C. The non-selective agar (CBA) allowed growth of C. jejuni over a longer period of time than the selective agar (Karmali). Furthermore, an enrichment broth (Bolton) allowed the recovery of all 19 C. jejuni strains during the 64 days of incubation at 4 degrees C. SIGNIFICANCE AND IMPACT OF THE STUDY: This study highlighted differences in culturability depending on culture conditions and on strain origin.     

PCR-restriction fragment length polymorphism assay (PCR-RFLP) as an useful tool for detection of mutation in gyrA gene at 86-THR position associated with fluoroquinolone resistance in Campylobacter jejuni

The aim of this study was to investigate the mutations in gyrA gene at Thr-86 position in fluoroquinolone resistant C. jejuni clinical isolates (2003-2005). The change of Thr to Ile at 86 position is associated with high-level resistance to fluoroquinolone in C. jejuni. Thirty five (58%) of 65 C. jejuni strains were found to be resistant to ciprofloxacin using E-test method. PCR-RFLP technique with the RsaI enzyme was used for the identification of mutation in gyrA gene. The primers spanning a part of the fluoroquinolone resistance determining region (QRDR) were designed based on the article of Alonso et al. and the gyrA sequence of C. jejuni (Gen Bank accession number LO4566). One of this primer had mismatch introduced at the second nucleotide from 3' end of the primer what gives an artificial RsaI cleavage site. All of the ciprofloxacin-resistant isolates contained a single)point mutation in the gyrA gene: the replacement of Thr 86 by Ile. The results showed that PCR-RFLP is a rapid and simple method for the detection of the high-level fluoroquinolone resistance in C. jejuni.     

Determination of antimicrobial susceptibilities of clinically isolated anaerobic bacteria by E-test, ATB-ANA and agar dilution

A total of 60 anaerobic strains were isolated from 322 clinical specimens. These isolates were tested for susceptibility to seven antibiotics (penicillin G, amoxicillin/clavulanic acid, cefoxitin, imipenem, chloramphenicol, metronidazole, clindamycin) by using ATB-ANA and Epsilometer test (E-test) strips and the results were compared with the gold standard agar dilution method. Imipenem was found as the most effective agent in vitro among the agents tested (100%). Susceptibility to penicillin G, amoxicillin/clavulanic acid, cefoxitin, chloramphenicol, metronidazole and clindamycin are 36.7%, 83.3%, 88.3%, 96.6%, 85% and 90%, respectively. E-test has showed a good correlation (r=0.62, p=0.001) statistically with the results of agar dilution (total agreement for all antibiotics changing between 90.01% and 98.45%) and a moderate correlation (r=0.45, p=0.048) with the results of ATB-ANA method (total agreement for all antibiotics changing between 75.46% and 98.76%). However, the routine use of agar dilution procedure is concluded to be cumbersome, whereas E-test method offers a reliable alternative.     

Antibiotic Susceptibility of Helicobacter pylori Clinical Isolates: Comparative Evaluation of Disk-Diffusion and E-Test Methods

Antimicrobial susceptibility of 25 Helicobacter pylori strains isolated from patients with acid peptic diseases were tested for in vitro sensitivity to commonly used antibiotics using disk-diffusion and E-test, methods. All strains tested were susceptible to tetracycline by E-test, with the minimum inhibitory concentration (MIC) values being <0.125 μg/ml for all strains except for 6 (<0.023 μg/ml). However 1 strain was resistant by disk-diffusion method. One strain was resistant to clarithromycin both by disk diffusion and E-test (MIC <48 μg/ml), and 1 strain was resistant only by disk diffusion. Only one strain was resistant to amoxicillin by disk diffusion and E-test (MIC >256 μg/ml). For ciprofloxacin, three strains were resistant by disk diffusion and two by E-test (MIC <32 μg/ml). Sixteen strains were resistant to metronidazole by disk diffusion and E-test (MIC ≥ 8 μg/ml), and 1 was resistant only by E-test (MIC <48 μg/ml). Overall, 64% of the strains were resistant to metronidazole. The MIC for metronidazole was also tested by agar-dilution method, and metronidazole resistant strains had an, MIC >8 μg/ml. The disk-diffusion method showed excellent correlation with E-test results; there was 100% agreement for amoxicillin a other antibiotics showed 90% to 95% accuracy. Disk diffusion is cheaper than E-test (approximately 2.6 cents vs. US$2.60), is easy to perform, and is a reliable method for testing H. pylori susceptibility to antimicrobial agents in the clinical microbiology laboratory.     

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.     

Susceptibility of Brazilian Staphylococcal Strains to Glycopeptides Evaluated by Different Testing Methods

Reports of staphylococci with reduced susceptibility to glycopeptides are cause for concern. This study evaluated the susceptibility of 84 staphylococci clinical isolates to glycopeptides by the disk diffusion, agar dilution, E-test, and BHIA screening methods. Vancomycin agar dilution showed all strains presented minimum inhibitory concentration (MIC) ranging from 0.5 to 2 μg/ml, and the E-test showed similar results. Teicoplanin agar dilution test showed MICs ranging from ≤ 0.5 to 2 μg/ml for Staphylococcus aureus and MICs ranging from <0.25 to 32 μg/ml for coagulase-negative Staphylococcus (CNS). Ten CNS isolates presented MICs ranging from 8 to 32 μg/ml for agar dilution and/or E-test. All the staphylococci were susceptible to vancomycin by the disk diffusion test (DDT), but two CNS isolates presented intermediate resistance to teicoplanin by the DDT and MICs of susceptibility, with two other CNS strains, teicoplanin-susceptible by the DDT, presented MICs of intermediate resistance. On the vancomycin-containing agar, 20 CNS isolates were able to grow, but no S. aureus strain. All these isolates showed MICs to teicoplanin (4–32 μg/ml) higher than those isolates that did not grow on the agar screen plate. PFGE of chromosomal SmaI digests showed a wide diversity of these CNS strains, without any predominance of a single PFGE pattern. Received: 25 May 2001 / Accepted: 9 July 2001     

Efficacy of the E-test in evaluating the antimicrobial susceptibility of anaerobic bacteria of veterinary interest

A study was made of the sensitivity of 39 clinical isolates of anaerobic bacteria to 10 antimicrobial agents. Minimal inhibitory concentrations (MICs) were calculated using a new method—the E-test (AB Biodisk, Solna, Sweden)—and compared with those obtained using the conventional agar dilution method. Agreement between the MICs obtained by the two methods with a variation of ± 2 dilutions was 78.7%. The E-test, though less sensitive than the conventional agar dilution method, may be of value in clinical veterinary practice when rapid selection of treatment for a given infectious process is required.     

Specific detection and confirmation of Campylobacter jejuni by DNA hybridization and PCR.

Conventional detection and confirmation methods for Campylobacter jejuni are lengthy and tedious. A rapid hybridization protocol in which a 1,475-bp chromogen-labelled DNA probe (pDT1720) and Campylobacter strains filtered and grown on 0.22-micron-pore-size hydrophobic grid membrane filters (HGMFs) are used was developed. Among the environmental and clinical isolates of C. jejuni, Campylobacter coli, Campylobacter jejuni subsp. doylei, Campylobacter lari, and Arcobacter nitrofigilis and a panel of 310 unrelated bacterial strains tested, only C. jejuni and C. jejuni subsp. doylei isolates hybridized with the probe under stringent conditions. The specificity of the probe was confirmed when the protocol was applied to spiked skim milk and chicken rinse samples. Based on the nucleotide sequence of pDT1720, a pair of oligonucleotide primers was designed for PCR amplification of DNA from Campylobacter spp. and other food pathogens grown overnight in selective Mueller-Hinton broth with cefoperazone and growth supplements. All C. jejuni strains tested, including DNase-producing strains and C. jejuni subsp. doylei, produced a specific 402-bp amplicon, as confirmed by restriction and Southern blot analysis. The detection range of the assay was as low as 3 CFU per PCR to as high as 10(5) CFU per PCR for pure cultures. Overnight enrichment of chicken rinse samples spiked initially with as little as approximately 10 CFU/ml produced amplicons after the PCR. No amplicon was detected with any of the other bacterial strains tested or from the chicken background microflora. Since C. jejuni is responsible for 99% of Campylobacter contamination in poultry, PCR and HGMF hybridization were performed on naturally contaminated chicken rinse samples, and the results were compared with the results of conventional cultural isolation on Preston agar. All samples confirmed to be culture positive for C. jejuni were also identified by DNA hybridization and PCR amplification, thus confirming that these DNA-based technologies are suitable alternatives to time-consuming conventional detection methods. DNA hybridization, besides being sensitive, also has the potential to be used in direct enumeration of C. jejuni organisms in chicken samples.     

Comparison of disc diffusion and epsilometer (E-test) testing techniques to determine antimicrobial susceptibiliy of Campylobacter isolates of food and human clinical origin

The antibiotic resistance profiles of 75 Campylobacter isolates of food and human clinical origin was determined by two agar diffusion susceptibility methods; disc diffusion and epsilometer-test (E-test). The most common therapeutic antimicrobials, erythromycin, ciprofloxacin and tetracycline were studied, along with chloramphenicol, ampicillin and naladixic acid. The resistance observed for each antimicrobial, as determined by both of methods, were statistically compared using Fisher two-tailed analysis.Of the six antimicrobials studied only two were shown to have statistically different patterns when resistance was compared by disc diffusion and E-test. The percentage of isolates resistant to clinically relevant antimicrobials using both techniques ranged from 6.6 to 21.3% for erythromycin, 25.3–26.6% for tetracycline and 33.3–36.0% for ciprofloxacin. The prevalence of multi-drug resistant (MDR) campylobacters (isolates resistant to 2 or more antimicrobials) for both disc diffusion and E-test was 44%. It can be concluded that, for four of the six antimicrobials assessed, antimicrobial resistance prevalences could be equally determined by either of the methods studied.     

Response of Campylobacter jejuni to combinations of ferrous sulphate and cadmium chloride

On Mueller Hinton (MH) agar, Campylobacter jejuni showed 20.0 and 30.9 mm zones of inhibition surrounding discs impregnated with 2.5 and 20 micrograms CdCl2 respectively. The minimal inhibitory concentration (MIC) ranged from 0.64 to 3.2 micrograms CdCl2/ml of MH agar for four C. jejuni strains. In the presence of 23 micrograms FeSO4/ml of MH the MIC increased to a range of 1.5-5.4 micrograms CdCl2/ml of MH. Moreover, the numbers of colonies present on MH supplemented with FeSO4 were greater than on MH without iron. The growth response of C. jejuni in the presence of 0.025% (w/v) FeSO4 in MH broth was increased about 10,000 fold in three of four strains when compared with the growth in unsupplemented MH broth. Zones of inhibition surrounding 20 micrograms discs of CdCl, were 50.6 and 24.4 mm on MH and Campy-BAP media respectively, with cells grown on MH. These results suggest that the blood-containing medium 'neutralized' the biocidal influence of the CdCl2. In comparison, C. jejuni inoculum from fluid thioglycollate (FT) medium showed smaller zones of inhibition. These decreased from 34.9 mm on MH agar to 19.6 mm on Campy-BAP agar, suggesting that components in the FT growth medium ameliorated the toxic influence of CdCl2. Atomic absorption spectroscopy analysis indicated mean values (mg/100 g dry weight) of selected metals bound by C. jejuni as: Cu, 10.4; Mg, 146; Na, 2385; Fe, 45.1; Zn, 13.0; and K, 172.     

in Vitro Activity of Antimycotic Agents Determined by e-Test Method Against Vaginal Shape Candida Species

Vaginal candidiasis continues to be a common cause of vaginal discharge, pruritus and other local complaints in women worldwide. Although numerous antimycotic agents are available for the treatment of yeast vaginitis there is little comparative data on the in vitro activity of these drugs. The objectives of this study were to isolate and identify the Candida species in the vagina and anus of patients treated in a gynaecology clinic, as well as determine the susceptibility to azolic compounds measured by the E-test method. Vaginal and rectal swabs were collected from 80 adult non-pregnant patients, seen at a gynaecological clinic, aged 18–59 years, with sexual activity, with and without vaginitis. The swabs were processed by methods routinely used for the detection of pathogenic yeasts. The susceptibility of the isolates to fluconazole, ketoconazole and itraconazole, was measured by the agar diffusion method (E-test), using RPMI 1640 medium with 2% glucose and phosphate buffer. Candida species (33) strains were isolated from 17 patients at similar proportions from both anatomical sites, and 12 patients harboured 24 strains of C. albicans in the vaginal and rectal tracts. Twenty one percent of the strains of C. albicans were resistant to ketoconazole, 54% were resistant to itraconazole and 0% were resistant to fluconazole. The sensitivity of strains isolated from the two sites were similar, indicating that these are strains of the same phenotype. This revised version was published online in August 2006 with corrections to the Cover Date.     

Primary resistance of Helicobacter pylori to antimicrobial agents in Polish children

Helicobacter pylori resistance to antimicrobial agents is an important factor compromising the efficacy of treatment. Therefore the aims of our study were: to determine the prevalence of H. pylori resistance to clarithromycin, metronidazole, amoxycillin and tetracycline in children prior to eradication therapy, to compare different methods of susceptibility testing and to detect mutations responsible for clarithromycin resistance. During 1996-2000, 259 H. pylori strains were isolated from antral gastric biopsies. Susceptibility to antimicrobials was determined by the agar dilution method and the Etest. Mutations in the 23S rRNA gene associated with clarithromycin resistance were analysed by PCR-RFLP and direct sequencing. Overall, ninety-six strains (37%) were resistant to metronidazole, 50 strains (19.3%) were resistant to clarithromycin, and 20 strains (7.7%) were simultaneously resistant to both drugs. All cultured isolates were sensitive to amoxycillin and only one isolate (0.4%) was resistant to tetracycline. The agar dilution method and the Etest showed a perfect category correlation for clarithromycin and 4% discrepancies for metronidazole. Primary resistance to clarithromycin was mainly associated with an A2143G mutation in the 23S rRNA gene of H. pylori. The study highlights the high prevalence of H. pylori primary resistance to clarithromycin in Polish children, which implies a need for pretreatment susceptibility testing.     

Susceptibility of Klebsiella pneumoniae isolated from urinary tract infections to quinolones

Urinary Tract Infections (UTIs) are the most prevalent infections worldwide both in males and females. K. pneumoniae is one of the major pathogens causing UTIs. Fluoroquinolones are effective drugs for treating infections caused by Klebsiella spp. The aim of this study was to evaluated the susceptibility to three fluoroquinolones of K. pneumoniae strains isolated from urine. The MICs of ciprofloxacin was determined by agar dilution method and the MICs of norfloxacin and gatifloxacin by E-test. Among analysed K. pneumoniae strains 86.7% was susceptible to gatifloxacine, 76.7% to norfloxacin and 51.2% to ciprofloxacine.     

Response of Campylobacter jejuni to combinations of ferrous sulphate and cadmium chloride

On Mueller Hinton (MH) agar, Campylobacter jejuni showed 20.0 and 30.9mm zones of inhibition surrounding discs impregnated with 2.5 and 20 μg CdCl₂ respectively. The minimal inhibitory concentration (MIC) ranged from 0.64 to 3.2 μg CdCl₂/ml of MH agar for four C. jejuni strains. In the presence of 23 μg FeSO₄/ml of MH the MIC increased to a range of 1.5–5.4 μg CdCl₂/ml of MH. Moreover, the numbers of colonies present on MH supplemented with FeSO₄ were greater than on MH without iron. The growth response of C. jejuni in the presence of 0.025% (w/v) FeSO₄ in MH broth was increased about 10000 fold in three of four strains when compared with the growth in unsupplemented MH broth. Zones of inhibition surrounding 20 μg discs of CdCl₂ were 50.6 and 24.4 mm on MH and Campy-BAP media respectively, with cells grown on MH. These results suggest that the blood-containing medium 'neutralized' the biocidal influence of the CdCl₂. In comparison, C. jejuni inoculum from fluid thioglycollate (FT) medium showed smaller zones of inhibition. These decreased from 34.9 mm on MH agar to 19.6 mm on Campy-BAP agar, suggesting that components in the FT growth medium ameliorated the toxic influence of CdCl₂. Atomic absorption spectroscopy analysis indicated mean values (mg/100 g dry weight) of selected metals bound by C. jejuni as: Cu, 10.4; Mg, 146; Na, 2385; Fe, 45.1; Zn, 13.0; and K, 172.     

Minimal inhibitory concentrations of Candida species to five antifungals by using the reference dilution micromethod and the E-test.

It is accepted that the frequency of candidosis has increased during the last decade, specially in hospitalized patients. The more frequent use of azole antifungals and the recognition of isolates of Candida sp resistant to these and other drugs such as 5-fluorocytosine constitute a great need for a reproducible and useful C. albicans in vitro susceptibility testing method for monitoring antifungal therapy in clinical mycological laboratories. The E-test is a novel agar diffussion technique for testing the susceptibility of yeasts against a defined continous gradient of drug and could be used by most clinical laboratories. In this study the E-test and the NCCLS reference microbroth method (M27-P guidelines) were used to determine the MICs of amphotericin B, 5-flucytosine, itraconazole, fluconazole and ketoconazole for 50 clinical isolates of Candida albicans, Torulopsis glabrata, C. tropicalis and Hansenula anomala and five reference ATCC strains. The main purpose of the study was to compare the results obtained by the two methods. In general good agreement (+/- 1 dilution) was otained between both methods, despite differences observed for some species-antifungal combinations in which the MICs were lower by the E-test than by the microbroth method. MICs for C. albicans and T. glabrata to amphotericin B were < 0.50 microg/mL. Two isolates of C. albicans and two others of H. anomala, showed MIC < 8 microg/mL for 5- flucytosine. All isolates of T. glabrata and 40% of C. albicans showed MICs > 16 microg/mL for fluconazole. The results of this study indicate that E-test is an alternative for susceptibility testing to the NCCLS reference method. Because its simplicity it seems to be an easier test for routine clinical laboratories.     

Heterogeneity of non-serotypable Campylobacter jejuni isolates

Several phenotypic and genotypic methods are currently used to identify subtypes of Campylobacter jejuni isolates. Of the phenotypic methods one, i.e. serotyping based on the heat stable antigen, is often hindered by the relatively large number of un-typable (NT) strains. Little is known, however, about the heterogeneity of the group formed by these NT strains. Therefore we serotyped 92 Hungarian, non-outbreak C. jejuni isolates and subjected the 28 NT strains to molecular analysis using PCR-RFLP of the flaA gene and to pulsed-field gel electrophoresis. With both methods the NT strains were classified into several molecular types (17 and 25, respectively), while the number of subgroups based on the results of the two techniques combined was twenty-six. These results indicate that the NT group of strains is extremely heterogeneous in Hungary, and the epidemiological connection between two NT isolates cannot be established or excluded without the use of molecular typing techniques.