The investigation of antibiotic residues, antibiotic resistance genes and antibiotic-resistant organisms in a drinking water reservoir system in Germany.

Between August 2018 and June 2019, a river system in Germany that supplies a drinking water reservoir and is subject to the discharge from two sewage treatment plants was monitored for antibiotic residues via liquid chromatography-tandem mass spectrometry, antibiotic resistance genes (including blaNDM, blaVIM, blaOXA-48, blaKPC, blaGIM, blaSME, blaIMI, blaIMP, blaSPM, blaSIM, blaOXA-23, blaOXA-24, blaOXA-51, blaOXA-58, mcr) via qualitative real-time PCR and antibiotic-resistant bacteria [belonging to the ESKAPE-group (Enterococcus faecium, Staphyhlococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter ssp.; with resistance against Carbapenemases, Cephalosporines and Colistin) and Escherichia coli] based on cultivation methods followed by a characterization via MALDI-TOF MS and susceptibility testing applying microdilution. Residues of macrolide antibiotics such as clarithromycin (up to 0.60 µg/L) and residues of sulfamethoxazole (up to 0.40 µg/L) and trimethoprim (up to 0.39 µg/L) were detected downstream of the sewage treatment plants. In addition, no antibiotic residues were detected upstream the respective sewage treatment plants, except for anhydroerythromycin (n = 1,

Association between antibiotic residues, antibiotic resistant bacteria and antibiotic resistance genes in anthropogenic wastewater - An evaluation of clinical influences.

The high use of antibiotics in human and veterinary medicine has led to a wide spread of antibiotics and antimicrobial resistance into the environment. In recent years, various studies have shown that antibiotic residues, resistant bacteria and resistance genes, occur in aquatic environments and that clinical wastewater seems to be a hot spot for the environmental spread of antibiotic resistance. Here a representative statistical analysis of various sampling points is presented, containing different proportions of clinically influenced wastewater. The statistical analysis contains the calculation of the odds ratios for any combination of antibiotics with resistant bacteria or resistance genes, respectively. The results were screened for an increased probability of detecting resistant bacteria, or resistance genes, with the simultaneous presence of antibiotic residues. Positive associated sets were then compared, with regards to the detected median concentration, at the investigated sampling points. All results show that the sampling points with the highest proportion of clinical wastewater always form a distinct cluster concerning resistance. The results shown in this study lead to the assumption that ciprofloxacin is a good indicator of the presence of multidrug resistant P. aeruginosa and extended spectrum ß-lactamase (ESBL)-producing Klebsiella spec., Enterobacter spec. and Citrobacter spec., as it positively relates with both parameters. Furthermore, a precise relationship between carbapenemase genes and meropenem, regarding the respective sampling sites, could be obtained. These results highlight the role of clinical wastewater for the dissemination and development of multidrug resistance.

Antibiotic resistant bacteria and resistance genes in biofilms in clinical wastewater networks.

Increasing isolation rates of resistant bacteria in the last years require identification of potential infection reservoirs in healthcare facilities. Especially the clinical wastewater network represents a potential source of antibiotic resistant bacteria. In this work, the siphons of the sanitary installations from 18 hospital rooms of two German hospitals were examined for antibiotic resistant bacteria and antibiotic residues including siphons of showers and washbasins and toilets in sanitary units of psychosomatic, haemato-oncological, and rehabilitation wards. In addition, in seven rooms of the haemato-oncological ward, the effect of 24 h of stagnation on the antibiotic concentrations and MDR (multi-drug-resistant) bacteria in biofilms was evaluated. Whereas no antibiotic residues were found in the psychosomatic ward, potential selective concentrations of piperacillin, meropenem and ciprofloxacin were detected at a rehabilitation ward and ciprofloxacin and trimethoprim were present at a haemato-oncology ward. Antibiotic resistant bacteria were isolated from the siphons of all wards, however in the psychosomatic ward, only one MDR strain with resistance to piperacillin, third generation cephalosporins and quinolones (3MRGN) was detected. In contrast, the other two wards yielded 11 carbapenemase producing MDR isolates and 15 3MRGN strains. The isolates from the haemato-oncological ward belonged mostly to two specific rare sequence types (ST) (P. aeruginosa ST823 and Enterobacter cloacae complex ST167). In conclusion, clinical wastewater systems represent a reservoir for multi-drug-resistant bacteria. Consequently, preventive and intervention measures should not start at the wastewater treatment in the treatment plant, but already in the immediate surroundings of the patient, in order to minimize the infection potential.

The occurrence of antimicrobial substances in toilet, sink and shower drainpipes of clinical units: A neglected source of antibiotic residues.

Antibiotics represent one of the most important drug groups used in the management of bacterial infections in humans and animals. Due to the increasing problem of antibiotic resistance, assurance of the antibacterial effectiveness of these substances has moved into the focus of public health. The reduction in antibiotic residues in wastewater and the environment may play a decisive role in the development of increasing rates of antibiotic resistance. The present study examines the wastewater of 31 patient rooms of various German clinics for possible residues of antibiotics, as well as the wastewater of five private households as a reference. To the best of our knowledge, this study shows for the first time that in hospitals with high antibiotic consumption rates, residues of these drugs can be regularly detected in toilets, sink siphons and shower drains at concentrations ranging from 0.02 µg·L-1 to a maximum of 79 mg·L-1. After complete flushing of the wastewater siphons, antibiotics are no longer detectable, but after temporal stagnation, the concentration of the active substances in the water phases of respective siphons increases again, suggesting that antibiotics persist through the washing process in biofilms. This study demonstrates that clinical wastewater systems offer further possibilities for the optimization of antibiotic resistance surveillance.

[Evaluation of heart rate variability for monitoring the depth of anaesthesia in dogs. Investigations based on total intravenous anaesthesia using propofol alone or in combination with dexmedetomidine or remifentanil]. / Evaluation der Herzratenvariabilität als Narkosetiefenmonitoring beim Hund. Untersuchung anhand total intravenöser Propofolanästhesie allein sowie in Kombination mit Dexmedetomidin oder Remifentanil.

OBJECTIVE: Evaluation of heart-rate variability (HRV) as an indicator for autonomous activity to monitor anaesthesia in dogs during three different total intravenous anaesthetic protocols and three anaesthetic depth levels as well as before and after electrical nociceptive stimulation. MATERIAL AND METHODS: Seven beagle dogs (14.3±1.7 kg) were used in a randomised experimental trial with a complete cross-over design. Each dog went through all three anaesthetic protocols, which were propofol alone (group P) and propofol combined with dexmedetomidine (3 µg/kg/h, group PD) or remifentanil (18 µg/kg/h, group PR). Propofol was given using target-controlled infusion. Three anaesthetic depth levels (light, medium, deep) were defined by target concentrations for propofol in the blood and were adapted to the individual animal and treatment (mean of 7, 9 and 11 µg/ml, and in combination with dexmedetomidine or remifentanil, a mean of 3, 5 and 7 µg/ml). During each anaesthetic level, a standardised supramaximal nociceptive electric stimulus (50 Hz, 50 V, 10 ms) was applied medially to the right forearm. The bipolar-derived electrocardiogram (ECG) was recorded continuously. For each anaesthetic depth, the RR-intervals recorded 2 minutes before and after each stimulation were included in the statistical analysis. Using an HRV analytical program (Kubios HRV), the frequency domain HRV-parameters low (LF) and high (HF) frequency and the time-domain HRV-parameters RR-intervals, standard deviation of all RR-intervals (SDNN) and the square root of the mean of the sum of the squares of the differences between consecutive RR-intervals (RMSSD) were determined. RESULTS: Neither the RR-intervals nor the currently available HRV-parameters which were derived from the RR-intervals were able to discriminate between the different anaesthetic depths levels. Nociception could only be represented by the RR-intervals. CONCLUSION: Overall, the investigated standard HRV parameters offered no additional information for the monitoring of anaesthetic depths at the investigated, clinically used dose rates.