Antibiotic resistance patterns of more than 120 000 clinical Escherichia coli isolates in Southeast Austria, 1998-2013.

Antibiotic resistance patterns of more than 120 000 clinical Escherichia coli isolates were retrospectively analysed. Isolates originated from both hospitalized patients and outpatients from the region of southeast Austria from 1998 to 2013. Except for amoxicillin/clavulanic acid, nitrofurantoin and piperacillin/tazobactam, all of the antibiotics analysed showed increasing proportions of resistant isolates over time, which were most prominent for ampicillin (from 25.4% in 1998 to 40% in 2013), cefotaxime (0.1% to 6.7%), ceftazidime (0.3% to 14.2%), ciprofloxacin (4.3% to 16.7%) and trimethoprim/sulfamethoxazole (14.6% to 24.8%). There was a marked increase in extended-spectrum ß-lactamase-positive isolates (0.1% to 6.3%) starting in 2005, with male patients and hospital-related patients showing a higher increase than female patients and outpatients. Proportions of resistant isolates for most antibiotics were generally higher for male patients and hospital-related patients. Amikacin, nitrofurantoin and trimethoprim/sulfamethoxazole showed a marked increase in resistance proportions among male subjects aged 10 to 19 years which were absent for female subjects, indicating a strong modulation potential of host characteristics.

Procalcitonin fails to predict bacteremia in SIRS patients: a cohort study.

BACKGROUND: Procalcitonin (PCT) has previously been proposed as useful marker to rule out bloodstream-infection (BSI). The objective of this study was to evaluate the sensitivity of different PCT cut-offs for prediction of BSI in patients with community (CA)- and hospital-acquired (HA)-BSI. METHODS: A total of 898 patients fulfilling systemic-inflammatory-response-syndrome (SIRS) criteria were enrolled in this prospective cohort study at the Medical University of Graz, Austria. Of those 666 patients had positive blood cultures (282 CA-BSI, 384 HA-BSI, enrolled between January 2011 and December 2012) and 232 negative blood cultures (enrolled between January 2011 and July 2011 at the emergency department). Blood samples for determination of laboratory infection markers (e.g. PCT) were collected simultaneously with blood cultures. RESULTS: Procalcitonin was significantly (p < 0.001) higher in SIRS patients with bacteremia/fungemia than in those without. Receiver operating characteristic curve analysis revealed an area under the curve (AUC) value of 0.675 for PCT (95% CI 0.636-0.714) for differentiating patients with BSI from those without. AUC for IL-6 was 0.558 (95% CI 0.515-0.600). However, even at the lowest cut-off evaluated (i.e. 0.1 ng/ml) PCT failed to predict BSI in 7% (n = 46) of patients. In the group of patients with SIRS and negative blood culture 79% (n = 185) had PCT levels > 0.1. CONCLUSION: Procalcitonin was significantly higher in patients with BSI than in those without and superior to IL-6 and CRP. The clinical importance of this is questionable, because a suitable PCT threshold for excluding BSI was not established. An approach where blood cultures are guided by PCT only can therefore not be recommended.

KPC-2 and OXA-48 carbapenemase-harbouring Enterobacteriaceae detected in an Austrian wastewater treatment plant.

Multiresistant Enterobacteriaceae, like carbapenemase-producing strains, have their primary reservoir in medical institutions. They can also be found with increasing tendency in other reservoirs. One possible way for entrance of multiresistant Enterobacteriaceae into the environment is via waste water. The aim of the study was to screen isolates from a wastewater treatment plant for the presence of carbapenemase-producing Enterobacteriaceae. Three isolates harboured carbapenemase genes, one Klebsiella pneumoniae harboured KPC-2 and one K. pneumoniae and one Escherichia coli harboured OXA-48. This is the first report of carbapenemase-harbouring Enterobacteriaceae isolated outside medical institutions in Austria and the first detection of KPC-harbouring K. pneumonia MLST ST 1245.

Comparison of extended-spectrum-ß-lactamase (ESBL) carrying Escherichia coli from sewage sludge and human urinary tract infection.

For many years, extended-spectrum-beta-lactamase (ESBL) producing bacteria were a problem mainly located in medical facilities. Within the last decade however, ESBL-producing bacteria have started spreading into the community and the environment. In this study, ESBL-producing Escherichia coli from sewage sludge were collected, analysed and compared to ESBL-E. coli from human urinary tract infections (UTIs). The dominant ESBL-gene-family in both sample groups was bla(CTX-M), which is the most prevalent ESBL-gene-family in human infection. Still, the distribution of ESBL genes and the frequency of additional antibiotic resistances differed in the two sample sets. Nevertheless, phenotyping did not divide isolates of the two sources into separate groups, suggesting similar strains in both sample sets. We speculate that an exchange is taking place between the ESBL E. coli populations in infected humans and sewage sludge, most likely by the entry of ESBL E. coli from UTIs into the sewage system.

Virulence and antimicrobial resistance genes in human MRSA ST398 isolates in Austria.

This study determined the genetic background of virulence and resistance genes of MRSA ST398 in Austria. From 2004 up to 2008 a total of 41 human isolates of MRSA ST398 were investigated for virulence and resistance gene patterns using DNA microarray chip analysis. Highly similar virulence gene profiles were found in 29 (70·7%) of the isolates but genes encoding Panton-Valentine leukocidin, enterotoxins, or toxic shock syndrome toxin were not detected. Genes conferring resistance to tetracycline and erythromycin-lincosamide were common as all but one of the isolates exhibited tetM and/or tetK, which are involved in tetracycline resistance, and 12 (29·9%) were positive for ermC, conferring resistance to erythromycin/lincosamide. SplitsTree analysis showed that 40 isolates were closely related. Changes in virulence and resistance gene patterns were minimal over the observed time period.

Emergence of carbapenem-resistant Enterobacteriaceae in Austria, 2001-2010.

We report the emergence of carbapenem-resistant Enterobacteriaceae in Austria. Over a 10-year period, carbapenem-resistant Enterobacteriaceae isolates were obtained from 13 hospitalized patients, with the first isolation in the year 2005 and a remarkable increase in the number of involved patients in 2010. Carbapenem-resistant Enterobacteriaceae comprise eight Klebsiella pneumoniae isolates, four Klebsiella oxytoca isolates, and one Escherichia coli isolate. The detected carbapenemases were the metallo-ß-lactamases New Delhi ß-lactamase, VIM and IMP, and the serin-ß-lactamase Klebsiella pneumoniae carbapenemase.

Antimicrobial resistance of Streptococcus pneumoniae in Southeast Austria, 1997-2008.

Antibiotic resistance in Streptococcus pneumoniae has increased worldwide but varies within geographical regions. We conducted a retrospective analysis of resistance in S. pneumoniae over a 12-year period to assess local and temporal trends in antibacterial resistance. From 1997 to 2008, a total of 1814 non-duplicate S. pneumoniae isolates were identified at the Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Austria. Antibiotic resistance was determined by the Clinical and Laboratory Standards Institute (CLSI) disk diffusion test. For penicillin, the minimum inhibitory concentration was determined by Etest. Susceptibility was defined according to CLSI interpretive criteria. For penicillin, resistance rates were consistently low at 0.2% over the 12-year study period. An increase in resistance was remarkable for erythromycin (3.5% in 1997; 14.7% in 2008), clindamycin (1.8% in 1997; 10.6% in 2008) and tetracycline (1.8% in 2000; 11.0% in 2008). For trimethoprim/sulfamethoxazole, resistance increased slightly to 9.2% in 2008. Quinolones showed a low resistance rate of 0.2% that persisted over the whole study period. In contrast to previously published national data, resistance to penicillin was observed to remain at a remarkably low and constant level. Although international surveillance programmes have set up sustainable and interlinked data networks, our results suggest that regional surveillance may still be needed as decision support for appropriate empirical antibiotic therapy in the local health setting.

Use of automated repetitive-sequence-based PCR for rapid laboratory confirmation of nosocomial outbreaks.

OBJECTIVE: Rapid and reliable diagnosis of genetic relatedness of clinical isolates in microbiologic laboratory is essential in case of nosocomial outbreak investigation. Most molecular techniques used to type microorganisms are technically demanding and time consuming. Currently repetitive-sequence-based PCR (rep-PCR) technique has been adapted to an automated format on the DiversiLab system (bioMérieux, Marcy l'Etoile, France). Aim of this study was to compare the performance of the DiversiLab system to that of pulsed-field gel electrophoresis (PFGE) in nosocomial outbreaks. METHODS: 122 clinical isolates (28 Methicillin-resistant Staphylococcus aureus (MRSA), 26 Acinetobacter baumannii, 45 extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae and 13 ESBL-producing Klebsiella oxytoca) were investigated. 70 isolates originated from six well-documented outbreaks, 52 were non-outbreak isolates. RESULTS: Concordant results for identification of outbreak and non-outbreak MRSA, A. baumannii and ESBL-producing K. pneumoniae strains were achieved with both methods. In the outbreak of ESBL-producing K. oxytoca automated rep-PCR was slightly more discriminatory than PFGE. Rep-PCR identified investigated ESBL-producing K. oxytoca outbreak-strains as indistinguishable or closely related, showing similarity of >90%, while PFGE identified these strains as indistinguishable. CONCLUSION: Automated rep-PCR assays on the DiversiLab system were used for MRSA, A. baumannii and for the first time ESBL-producing Klebsiella spp. and proved as a rapid and reliable method for molecular analysis of nosocomial outbreaks.

Isolation of Gordonia terrae from a patient with catheter-related bacteraemia.

A cornyeform bacterium was isolated from a blood culture from a 24-year-old man with familial hypertrophic non-obstructive cardiomyopathy, chronic abuse of anabolic steroids and prior admission to hospital because of clinical signs of sepsis. 16S rRNA gene analysis unambiguously identified Gordonia terrae.

Viridans streptococci in endocarditis and neutropenic sepsis: biofilm formation and effects of antibiotics.

OBJECTIVES: Viridans group streptococci (VGS) are a frequent cause of bacterial endocarditis or sepsis in patients with neutropenia. Endocarditis in particular, is associated with plaque formation on the endocardium and valve leaflets whereas VGS septicaemia in neutropenic patients is caused by the influx of oral flora bacteria through mucositic lesions. This study examined the in vitro potency for biofilm formation of clinical VGS bloodstream isolates, and the effects of antibiotics on these biofilms. METHODS: During the years 1998-2000, 40 VGS bloodstream isolates from 18 patients with endocarditis and 22 patients with severe sepsis and neutropenia were collected. The MICs of penicillin, teicoplanin and moxifloxacin were determined using the microdilution broth method according to NCCLS criteria. Biofilms were grown in microtitre plates, dyed with Crystal Violet, and the mean optical density (OD) was used for quantification. Biofilms were incubated with penicillin, teicoplanin and moxifloxacin at various concentrations starting with the MICs for the respective isolates tested. RESULTS: Isolates from eight out of 18 patients with endocarditis and six out of 22 patients with neutropenia formed biofilms (not significant). For the 14 isolates, the MIC(90)s (range) of penicillin, teicoplanin and moxifloxacin were 0.5 mg/L (0.001-0.5), 0.125 mg/L (0.025-0.125) and 0.5 mg/L (0.05-0.5), respectively. Generally, biofilms persisted although incubated with the antibiotics up to concentrations of 128 x MIC. However, the ODs of biofilms after incubation with an antibiotic were significantly lower than the ODs of biofilms without antibiotic (P<0.05). A significant decrease in the biofilms with increasing antibiotic concentrations was observed for teicoplanin and moxifloxacin, but not for penicillin G. CONCLUSIONS: VGS isolated from patients with endocarditis and patients with sepsis and neutropenia form biofilms. Biofilms persist even when exposed to antibiotics at concentrations up to 128 x MIC. Nevertheless, teicoplanin and moxifloxacin reduced the density of the biofilms at concentrations >/=16 x MIC. Thus, testing the effects of antibiotics on biofilms may supply useful information in addition to standard in vitro testing, particularly in diseases where biofilm formation is involved in the pathogenesis.

Qualitative detection of Legionella species in bronchoalveolar lavages and induced sputa by automated DNA extraction and real-time polymerase chain reaction.

Molecular assays for qualitative detection of Legionella spp. in clinical specimens were evaluated. DNA extraction was done either with a fully automated DNA extraction protocol on the MagNA Pure LC System or with manual DNA extraction. Amplification and detection were done by real-time polymerase chain reaction (PCR) on the LightCycler (LC) instrument. Oligonucleotides were derived from the 16S rRNA gene of Legionella spp. The assays included a specially designed DNA fragment as Legionella-specific internal control. For both molecular assays, the detection limit was determined to be 5 CFU per LC PCR run. Sixty-one clinical specimens were tested with the molecular assays. Results were compared to culture. Five samples were found to be positive with the molecular assays. Three of them were positive in culture. No inhibition was found throughout the whole study. In conclusion, the molecular assays described may lead to safe and early diagnosis of Legionnaires' disease. They proved to be suitable for the routine molecular diagnostics laboratory.