Gebhard Feierl

Antibiotic resistance of E. coli in sewage and sludge

The aim of the study is the evaluation of resistance patterns of E. coli in wastewater treatment plants without an evaluation of basic antibiotic resistance mechanisms. Investigations have been done in sewage, sludge and receiving waters from three different sewage treatment plants in southern Austria. A total of 767 E. coli isolates were tested regarding their resistance to 24 different antibiotics. The highest resistance rates were found in E. coli strains of a sewage treatment plant which treats not only municipal sewage but also sewage from a hospital. Among the antimicrobial agents tested, the highest resistance rates in the penicillin group were found for Ampicillin (AM) (up to 18%) and Piperacillin (PIP) (up to 12%); in the cephalosporin group for Cefalothin (CF) (up to 35%) and Cefuroxime-Axetil (CXMAX) (up to 11%); in the group of quinolones for Nalidixic acid (NA) (up to 15%); and for Trimethoprime/Sulfamethoxazole (SXT) (up to 13%) and for Tetracycline (TE) (57%). Median values for E. coli in the inflow (crude sewage) of the plants were between 2.0 x 10(4) and 6.1 x 10(4)CFU/ml (Coli ID-agar, BioMerieux 42017) but showed a 200-fold reduction in all three plants in the effluent. Nevertheless, more than 10(2)CFU E. coli/ml reached the receiving water and thus sewage treatment processes contribute to the dissemination of resistant bacteria in the environment.

Species-Specific Identification of Campylobacters by Partial 16S rRNA Gene Sequencing

ABSTRACT Species-specific identification of campylobacters is problematic, primarily due to the absence of suitable biochemical assays and the existence of atypical strains. 16S rRNA gene (16S rDNA)-based identification of bacteria offers a possible alternative when phenotypic tests fail. Therefore, we evaluated the reliability of 16S rDNA sequencing for the species-specific identification of campylobacters. Sequence analyses were performed by using almost 94% of the complete 16S rRNA genes of 135 phenotypically characterized Campylobacter strains, including all known taxa of this genus. It was shown that 16S rDNA analysis enables specific identification of most Campylobacter species. The exception was a lack of discrimination among the taxa Campylobacter jejuni and C. coli and atypical C. lari strains, which shared identical or nearly identical 16S rDNA sequences. Subsequently, it was investigated whether partial 16S rDNA sequences are sufficient to determine species identity. Sequence alignments led to the identification of four 16S rDNA regions with high degrees of interspecies variation but with highly conserved sequence patterns within the respective species. A simple protocol based on the analysis of these sequence patterns was developed, which enabled the unambiguous identification of the majority of Campylobacter species. We recommend 16S rDNA sequence analysis as an effective, rapid procedure for the specific identification of campylobacters.

ESBL-producing E. coli in Austrian sewage sludge

The aim of this study was to investigate the degree of contamination of sewage sludge with ESBL-producing Escherichia coli strains and the effectiveness of different sewage sludge treatment methods. Monthly sewage sludge samples were collected between January and September 2009 in 5 different sewage treatment plants and tested for the presence of ESBL E. coli. In addition, the number of colony forming units (CFU) of E. coli and coliform bacteria before and after the different sludge treatment methods (aerobic/anaerobic digestion, lime stabilization, and thermal treatment) was investigated. Of the 72 sewage sludge samples investigated, ESBL-positive E. coli were found in 44 (61.1%) sewage sludge samples. The classification of beta-lactamase groups was carried out in 15 strains resulting in the detection of 2 different groups (CTX-M and TEM) of bla genes. All 15 of them had a CTX-M gene and 4 of these strains furthermore carried a TEM gene. With regard to the CFU of E. coli and coliform bacteria, thermal treatment and lime stabilization following dehydration sufficiently reduced pathogen concentrations. The plants using merely stabilization and dehydration showed an increase of E. coli and coliform bacteria and thus also an increase in ESBL-producing E. coli.

Emergence of Enterobacteriaceae isolates producing CTX-M extended-spectrum beta-lactamase in Austria

ABSTRACT Among 149 extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae isolates collected from patients in southeast Austria from 1998 to 2004, 38 Escherichia coli isolates and 11 Klebsiella spp. were CTX-M producers. The proportion of CTX-M-producers among all ESBL producers rose from 0% in 1998 to 58% in 2004. In general, CTX-M-producers had heterogeneous pulsed-field gel electrophoresis patterns, but one E. coli isolate was identical to a United Kingdom epidemic CTX-M-15-producing strain, although no epidemiological link with the United Kingdom was apparent.

Barbecued Chicken Causing a Multi-State Outbreak of Campylobacter jejuni Enteritis

Abstract.Background: Although the microbiological safety of food has improved, food-borne disease remains a significant cause of morbidity and mortality in Europe. Patients and Methods: We investigated an outbreak of Campylobacter jejuni enteritis attributed to chicken meat, affecting five out of six people attending a private barbecue party in Germany. Patients fell ill in Germany, in Liechtenstein and in Austria. 80% of the cases had been exposed to barbecued chicken; the case that denied having eaten chicken was the party host, who also handled all the food. Three of four patients submitting stool specimens had culture-confirmed C. jejuni infection. Results: The chicken meat was purchased in the Tyrol (Austria) and originated from a flock of 55,600 chickens raised in Carinthia (Austria). Caecal swabs were obtained in 7 weeks later from 22 chicken at the incriminated farm: 18 of the 22 samples yielded C. jejuni. The same day, six carcasses out of 22,000 slaughtered animals from the incriminated farm were tested and all six food samples yielded C. jejuni. Outbreak-associated human isolates yielded pulsed-field gel electrophoresis patterns indistinguishable from each other and from the meat isolates, but different from four human control strains and from 13 of 16 isolates from caecal swabs. Conclusion: Our data show that the outbreak clone had been colonizing the slaughterhouse and was cross-contaminating chickens there. The geographic mobility of people and food necessitates proper epidemiologic investigations to avoid overestimation of the proportion of sporadic occurrence of campylobacteriosis.

Epidemiologic application of pulsed-field gel electrophoresis to an outbreak of Campylobacter jejuni in an Austrian youth centre.

We report the first documented Campylobacter jejuni outbreak in an Austrian youth centre. Sixty-four children were involved of which 38 showed classical signs of campylobacter gastroenteritis. Since unpasteurized milk distributed by a local dairy was suspected to be the source of infection, stool samples were collected from 20 cows providing the milk. Five of the cows tested positive for C. jejuni. These isolates together with 37 clinical samples were compared by pulsed-field-gel electrophoresis (PFGE). The PFGE patterns, using the restriction endonucleases SmaI and SalI, were identical for the human and bovine isolates. This finding confirmed that the outbreak was caused by the consumption of unpasteurized milk contaminated with C. jejuni.

Transmission of Campylobacter hyointestinalis from a Pig to a Human

ABSTRACT We report on a case of human gastroenteritis caused by the pathogen Campylobacter hyointestinalis. Recurrent watery diarrhea and intermittent vomiting were the most significant symptoms of the previously healthy patient. Whole-cell protein electrophoresis and 16S rRNA gene sequencing were used to identify this Campylobacter species. Investigation of the patients surroundings led to the recovery of a second C. hyointestinalis strain originating from porcine feces. Subsequent typing of the human and the porcine isolates by pulsed-field gel electrophoresis revealed similar macrorestriction profiles, indicating transmission of this pathogen.

Lethal brain abscess due to the fungus Scedosporium apiospermum (teleomorph Pseudallescheria boydii) after a near-drowning incident: case report and review of the literature

A 39-year-old healthy man developed a brain abscess weeks after a near-drowning incident. Scedosporium apiospermum, the anamorph of Pseudallescheria boydii, was isolated from the abscess. The patient died 153 days after the accident despite antifungal therapy. We discuss the role of antifungals and review the literature for comparable cases.

Modified culture method detects a high diversity of fungal species in cystic fibrosis patients

Cystic fibrosis (CF) is one of the most common genetic lung diseases worldwide. The production of sticky viscous mucus leads to enhanced bacterial colonization and infection, but yeasts and filamentous fungi are also found abundantly in the mucus of patients suffering from CF. The role of fungi in the airways of CF patients is still not understood completely. Furthermore, recent investigations have shown that the spectrum of fungi isolated from the airways of CF patients depends strongly on the methods used. In this study, different mycological culture methods were compared: culture with a native inoculum, culture with homogenization of CF sputum, and culture after homogenization and serial dilutions of CF sputum. Altogether, 934 sputum samples from 113 patients were examined from July 2009 through December 2011. A total of 1,744 fungal isolates was recovered; 20 different yeasts and 14 filamentous fungal species were identified. Candida albicans, C. dubliniensis, and C. parapsilosis were the most common species of yeast. For the filamentous fungi, Aspergillus fumigatus was the most common, followed by Scedosporium apiospermum/Pseudallescheria boydii group and A. terreus. Many fungal, species such as Exophiala dermatitidis, Rasamsonia (Geosmithia) argillacea, and others, were isolated only from homogenized sputum samples. The longitudinal data also show that fungal colonization of CF patients is quite stable, even when treated with itraconazole. In conclusion, we recommend homogenizing CF sputa with a mucolyticum, to prepare serial dilutions, and to use appropriate fungal culture media with added antibiotics.

Orally administered colistin leads to colistin-resistant intestinal flora and fails to prevent faecal colonisation with extended-spectrum β-lactamase-producing enterobacteria in hospitalised newborns.

Colonisation and infection with extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) is an emerging problem. The aim of this study was to investigate whether colistin, which is reported to be effective against multiresistant enterobacteria, prevents ESBL-E colonisation in neonates. For prophylaxis of necrotising enterocolitis, oral gentamicin (15 mg/kg/day) is routinely used in all neonates hospitalised at the Neonatal Intensive Care Unit of University Hospital Graz (Austria). During the study period from May 2005 to September 2007, three ESBL-E outbreaks (total duration 18 months) occurred. During these outbreaks, gentamicin was immediately replaced by oral colistin (8 mg/kg/day) in all hospitalised neonates. All neonates colonised with ESBL-E during the study period were retrospectively analysed with regard to the influence of colistin on ESBL-E colonisation. Genetic relatedness of isolates was assessed by repetitive sequence-based polymerase chain reaction (rep-PCR). During the study period, 30 (4.5%) of 667 neonates were colonised with ESBL-E. Twelve of twenty-one patients colonised with Klebsiella pneumoniae (ESBL-Kp) and one of nine patients colonised with Klebsiella oxytoca (ESBL-Ko) had received oral colistin at time of colonisation with ESBL-E. Amongst ESBL-Kp, the rate of colistin resistance was significantly higher in the colistin group (P=0.0075). Four different clones of ESBL-Kp and three different clones of ESBL-Ko were isolated, indicating the occurrence of patient-to-patient transmission. Colistin-resistant as well as colistin-susceptible isolates were detected within the same clones, indicating induction of resistance. At the dosage used, oral colistin did not prevent colonisation with ESBL-E and appeared to select colistin-resistant strains or to induce colistin resistance.