[Development of antimicrobial resistance in Germany : What is the current situation?]

Pathogens and Shift of Resistance in Early Infections after Operative Fracture Fixation

Background: Surgical site infections (SSIs) remain a challenge for the healthcare system. During the last 30 years, the literature has shown an increase of gram-negative bacterial strains in multiple infectious sites and that cephalosporins have replaced penicillin as the gold standard in peri-operative antibiotic prophylaxis. This study aims to examine the recent bacterial spectrum in orthopedic early SSIs and to compare it with a historical cohort. Patients and Methods: Patients in a level 1 trauma center with an SSI within six weeks after open fixation of a fracture were analyzed in two adjacent periods from 2007 to 2012 (data pool 1; DP1) and 2013 to 2017 (data pool 2; DP2), retrospectively. The detected microbiologic pathogens and the associated resistograms from both time periods were compared. Results: Six hundred eighty-one smear tests and respective pathogens from the wounds of 463 patients (mean age, 62.6 ± 20 years) with SSIs were analyzed. The following pathogens were found most frequent: Staphylococcus epidermidis (DP1, 20.6%; DP2, 26.3%), Staphylococcus aureus (DP1, 27.1%; DP2, 16.5%), Enterococcus faecalis (DP1, 13.7%; DP2, 11.1%), Bacillus sp. (DP1, 3.0%; DP2, 5.3%), Escherichia coli (DP1, 5.1%; DP2, 4.1%), Pseudomonas aeruginosa (DP1, 3.7%; DP2, 2.5%). In DP2, there were lower primary early infection rates with Staphylococcus aureus than in DP1 (p = 0.002). In DP2, Staphylococcus epidermidis showed an oxacillin resistance in 90.6% and an increased resistance (79.8%; p = 0.069) to several classes of antibiotic agents compared to DP1. Conclusions: No bacterial shift toward gram-negative species was observed in this investigation. However, Staphylococcus epidermidis showed an increased antibiotic resistance in the more recent patient cohort. The incidence of SSIs with Staphylococcus aureus decreased substantially.

Hygiene in der Dermatologie: multiresistente gram-negative Stäbchen (MRGN) und Vancomycin-resistente Enterokokken (VRE)

Bakterielle Besiedlungen von Haut und Wunden sowie Infektionen mit Problemkeimen spielen in der Dermatologie eine wichtige Rolle. Neben Methicillin-resistenter Staphylococcus aureus (MRSA) finden sich auch zunehmend MRGN und VRE bei Wund- und Weichteilinfektionen. Da sowohl für multiresistente gram-negative Stäbchen (MRGN) als auch Vancomycin-resistente Enterokokken (VRE) das Haupt-Reservoir der menschliche Darm ist, ist eine Sanierung nicht möglich. Daher ist das Ziel, bei diesen beiden multiresistenten Erregerarten durch Prävention bei Risikopatienten und geeignete Hygiene-Maßnahmen eine Reduktion in zusätzlichen Reservoiren wie bspw. chronischen Wunden zu erreichen sowie durch richtigen Einsatz von Antibiotika eine weitere Zunahme von MRGN- und VRE-Inzidenzen zu verhindern. Aus diesem Grund ist bei der Infektionsprävention ein besonderer Fokus auf das Hygienemanagement zu legen. Dieses soll praxisnah, effizient und nachvollziehbar, damit also auch vermittelbar sein. Die Antibiotikastrategie soll so ausgestaltet sein, dass die Selektion resistenter Erreger möglichst verhindert wird. Dies gilt gleichermaßen für das Krankenhaus wie auch das ambulante Umfeld von Patienten.

Evaluating Tannins and Flavonoids from Traditionally Used Medicinal Plants with Biofilm Inhibitory Effects against MRGN E. coli

In the search for alternative treatment options for infections with multi-resistant germs, traditionally used medicinal plants are currently being examined more intensively. In this study, the antimicrobial and anti-biofilm activities of 14 herbal drugs were investigated. Nine of the tested drugs were traditionally used in Europe for treatment of local infections. For comparison, another five drugs monographed in the European Pharmacopoeia were used. Additionally, the total tannin and flavonoid contents of all tested drugs were analyzed. HPLC fingerprints were recorded to obtain further insights into the components of the extracts. The aim of the study was to identify herbal drugs that might be useable for treatment of infectious diseases, even with multidrug resistant E. coli, and to correlate the antimicrobial activity with the total content of tannins and flavonoids. The agar diffusion test and anti-biofilm assay were used to evaluate the antimicrobial potential of different extracts from the plants. Colorimetric methods (from European Pharmacopeia) were used for determination of total tannins and flavonoids. The direct antimicrobial activity of most of the tested extracts was low to moderate. The anti-biofilm activity was found to be down to 10 µg mL−1 for some extracts. Tannin contents between 2.2% and 10.4% of dry weight and total flavonoid contents between 0.1% and 1.6% were found. Correlation analysis indicates that the antimicrobial and the anti-biofilm activity is significantly (p < 0.05) dependent on tannin content, but not on flavonoid content. The data analysis revealed that tannin-rich herbal drugs inhibit pathogens in different ways. Thus, some of the tested herbal drugs might be useable for local infections with multi-resistant biofilm-forming pathogens. For some of the tested drugs, this is the first report about anti-biofilm activity, as well as total tannin and flavonoid content.

In vitro activity of cefiderocol against Gram-negative bacterial pathogens in Germany

OBJECTIVES

Widespread antimicrobial resistance in Gram-negative bacteria (GNB), particularly carbapenem resistance, represents a major clinical challenge. Cefiderocol is a novel siderophore cephalosporin active against all carbapenemase classes.

METHODS

We evaluated the in vitro activity of cefiderocol and other antibacterial agents (ceftazidime/avibactam, ceftolozane/tazobactam, colistin and meropenem) against GNB isolates collected in Germany (2013-2018) as part of two multinational studies. Antimicrobial susceptibility testing was performed by broth microdilution. Minimum inhibitory concentrations were interpreted according to EUCAST breakpoints.

RESULTS

Cefiderocol had high activity against GNB isolates (N = 2298), encompassing both Enterobacterales (n = 1562) and non-fermenter species (n = 736), and maintained high activity against carbapenem-resistant strains (n = 211). The activity of cefiderocol against Enterobacterales was equivalent to that of ceftazidime/avibactam and colistin, while ceftolozane/tazobactam was somewhat less active. Against non-fermenter species, cefiderocol displayed equivalent activity to colistin; both of these agents were more active than ceftazidime/avibactam and ceftolozane/tazobactam. Colistin had similar activity to cefiderocol against the majority of species. These patterns of activity were echoed in carbapenem-resistant isolates. The high activity of cefiderocol was independent of infection site, whereas other antibacterial agents demonstrated slightly lower activity against isolates causing pneumonia compared with those from other key infection sites.

CONCLUSION

Cefiderocol exhibited consistently high in vitro activity against a variety of GNB isolates collected in Germany, including resistant phenotypes, across multiple infection sites. These data suggest that cefiderocol is an effective choice of antibacterial agent in patients with GNB infection, regardless of species and resistance phenotype to other agents.

Novel insights into pivotal risk factors for rectal carriage of extended-spectrum-β-lactamase-producing enterobacterales within the general population in Lower Saxony, Germany

AIMS

To estimate the prevalence of extended-spectrum-β-lactamase (ESBL)-producing enterobacterales (ESBL-E) carriage in the general population of Lower Saxony, Germany, and to identify risk factors for being colonized.

METHODS AND RESULTS

Participants were recruited through local press and information events. Detection of ESBL-E by culture was conducted using ESBL-selective chromagar plates containing third-generation cephalosporins. Identification of pathogens was performed using matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF)_technology on Vitek mass spectrometry. Antibiotic susceptibility testing was conducted by microdilution (Vitek II) and an ESBL confirmation assay was carried out using a combination disk test. Of 527 randomly collected stool samples from healthy volunteers, 5.5% were tested positive for ESBL-E. Post-stratification for age and gender yielded a similar population estimate (5.9%). People traveling abroad and taking antibiotics had the greatest rectal ESBL-E carriage.

CONCLUSIONS

Potential risk factors (eg, working in healthcare facilities, recent inpatient stay) did not attribute to rectal ESBL-E carriage as other factors (eg, travelling, taking antibiotics). Rectal ESBL-E carriage within the general population seems to be high.

SIGNIFICANCE AND IMPACT OF THE STUDY

The known risk factors for carriage with MDRO might not be fully applicable to ESBL-E and require further examination in order to develop effective strategies for the prevention of ESBL-E dissemination within the general population.

[Laboratory study on bacteriological aspects of beverages and thickeners for dysphagia patients : Growth survey of Escherichia coli on thickeners and beverages]

BACKGROUND

Currently, there is little evidence-based guidance on bacteriological aspects of thickeners or beverages for dysphagia patients in Germany that can be recommended to prevent aspiration pneumonia. Therefore, the aim of this study was to evaluate the lowest cell amount of E. coli on M9 agar media with beverages and thickeners.

METHODOLOGY

In the laboratory experiment 1 · 10⁷ cells of E. coli were plated on a defined minimal medium (M9 agar plates) with different carbon sources and incubated at 37 °C for 2 days. The increase in cell number was determined using a photometer. Carbon sources were water, beer, orange juice, thickened beer, maltodextrin-xanthan gum-based thickeners, corn starch-based thickeners and potato starch-based thickeners.

RESULTS

The lowest E. coli cell amount was measured on water compared to beer, orange juice and all thickeners. A higher E. coli cell count was measured on maltodextrin-based thickeners than on potato starch-based and corn starch-based thickeners.

DISCUSSION

In the present laboratory experiment, no individual risk factors for the development of aspiration pneumonia in humans were considered; however, initial bacteriological evidence for dysphagia patients could be collected. Due to the high growth of E. coli on maltodextrin, yeast, fructose and glucose, these ingredients should be used with caution by dysphagia patients. Further research on thickeners and beverages is needed to make a comprehensive recommendation for action in this aspect.

[Hospital hygiene 2.0 : Cross-interface, molecular epidemiological early warning systems for prevention of multidrug-resistant pathogens]

Infections caused by multidrug-resistant pathogens and their inpatient (nosocomial) and outpatient spread, pose increasing challenges to our healthcare system. Control strategies are derived from vertical (individual, pathogen-specific) and horizontal (general, pathogen-unspecific) preventive measures. The discussion of a competing "either or" has not proven to be effective in the past. In addition, the problem of multidrug-resistant pathogens cannot be solved solely in inpatient health care: the goals are a seamless communication and transparent cooperation between all actors in the healthcare system. Nowadays, modern molecular methods for pathogen typing are available, with the help of which transmission pathways can be clarified and hospital hygiene measures can be efficiently controlled. These procedures will be used increasingly more in the future to combat the problem of multidrug resistance across interfaces within regional network structures.

[Occupationally acquired MRSA colonization and occupational dermatological assessments (BK-No. 3101 in the German list of Occupational Diseases) : Analysis of the DGUV documentation and expert opinion on a case with work-related MRSA-triggered atopic dermatitis]

BACKGROUND

Person-to-person transmitted infectious diseases can cause occupational diseases (OD). These are subsumed as BK-No. 3101 in the German list of OD which applies for individuals with a considerably higher risk for infection as a consequence of their professional activity compared to the general population.

OBJECTIVES

The special medical and insurance law aspects of a work-related MRSA colonization are presented using the example of an expert opinion case and an evaluation of the BK reports of suspected occupational disease (BK No. 3101) of the German Social Accident Insurance (DGUV).

PATIENTS AND METHODS

The BK documentation of the DGUV from 2007-2012 and the patient cohort from the Department of Dermatology, University Hospital Erlangen, presenting for expert assessment from 2007-2012 were retrospectively analysed for human-to-human transmitted infectious diseases of the skin (BK-No. 3101).

RESULTS

Person-to-person transmission of infectious diseases of the skin is rare in the field of occupational dermatology. In the DGUV cohort, suspected BK-No. 3101cases amounted to 2.6% of all notified cases; recognized BK-No. 3101 cases accounted for 4.2% of all recognized cases, amongst which 9 were caused by MRSA. In contrast to a symptomatic infection, an asymptomatic MRSA colonization is not being recognized as BK-No. 3101. Bacterial superantigens can trigger atopic dermatitis (AD). In particular cases, occupationally acquired MRSA can elicit AD and may justify classification as an OD (BK-No. 3101).

CONCLUSIONS

Early detection of MRSA colonization and eradication are necessary for rehabilitation. Management of skin diseases due to infectious diseases within the framework of OD is presented.

Anamnestic risk factor evaluation of patients carrying carbapenem-resistant Enterobacterales and/or Acinetobacter baumannii - impact on infection control management at a German University Hospital

Background: Carbapenem-resistant Enterobacterales and Acinetobacterbaumannii are of major concern in terms of infection prevention and control. This study evaluated factors that may increase the frequency of Enterobacterales and A. baumannii with carbapenem resistance (CR) in patients admitted to a German University Hospital for implementation of optimized infection control management.

Methods: A five-year-retrospective epidemiological cohort analysis was conducted on anamnestic risk factors for carrying Enterobacterales and/or A. baumannii with CR in patients who were first tested positive for these species at University Hospital Frankfurt (UHF) between January 2013 and June 2018.

Results: 364 patients were tested positive for Enterobacterales and/or A. baumannii with CR, resulting in n=400 bacterial isolates in total, with Klebsiella pneumoniae being the most frequently detected species (n=146/400; 36.5%; 95% confidence interval: 31.8–41.4). In patients who were tested positive for Enterobacterales and/or A. baumannii with CR, any hospital stay within the previous 12 months was the most frequently reported common factor (n=275/364; 75.5%; 70.8–79.9).

Conclusion: A hospital stay within the previous 12 months, including hospitals in Germany and abroad, is a frequent characteristic of patients who tested positive for Enterobacterales and/or A. baumannii with CR. Upon admission, any previous hospital stay of the given patient within the previous 12 months should be determined. Infection control strategies such as screening measures need to be adapted to these patient groups in hospital settings. In order to reflect the varying determinants in “nosocomial” cases in greater detail, the existing criteria used to characterize “nosocomial detection” of gram-negative bacteria with CR should be reviewed.

Silver-decorated, light-activatable polymeric antimicrobials for combined chemo-photodynamic therapy of drug-resistant bacterial infection

In this article, we describe a silver-decorated, light-activatable polymeric antimicrobial with strong synergistic chemo-photodynamic effect to combat bacterial infections.

[Antibiotic stewardship : Measures for optimizing prescription of anti-infective agents]

Antibiotic stewardship (ABS) comprises a bundle of different interventions to improve anti-infective treatment in a hospital setting. An important component of ABS interventions is the interdisciplinary approach to infection management. Besides improving infrastructural aspects on a hospital level, including surveillance of the use of anti-infective agents and nosocomial infections, collation and interpretation of statistics on resistance and formulation of local treatment guidelines, ABS teams go to the wards and advise treating physicians on antibiotic therapy. Frequent approaches for optimization are selection of substances, administration route, dosing of medication and duration of treatment. An important overall objective of ABS is the reduction of resistance induction in order to preserve the therapeutic efficiency of antibiotics. A number of studies have shown that this goal can be achieved in different clinical settings without negatively affecting patient outcome. The strategies of ABS can also be applied with no problems to critically ill patients on the intensive care unit.

Occupational Infection Risk with Multidrug-Resistant Organisms in Health Personnel-A Systematic Review

The increase in multi-drug-resistant organisms (MDROs) in the last years has become a public health problem. MDROs are partially responsible for numerous nosocomial infections, extended hospital stays, high costs, and high mortality. In addition to methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE), Gram-negative bacteria are also a key area of focus. The knowledge of MDROs among the medical staff in the occupational context is limited, with the exception of MRSA. Therefore, a systematic review was carried out to determine the occupational risk for employees posed by MDROs. The search included studies from the year 2000 onwards among personnel who had contact with MDROs. A total of 22 primarily cross-sectional studies in hospital or geriatric care settings were found, with large differences regarding number of participants, examination method, inclusion of a control group, and study quality. The most frequently examined pathogens were extended-spectrum ß-lactamase (ESBL)-producing bacteria with a prevalence of 2.6-48.5%, VRE (0-9.6%), and MRSA (0.9-14.5%). There are only few qualitatively good studies available on MDROs' risk infection for employees in the health service. Any comparison of the results was limited by data heterogeneity. More research is required to describe the occupational risk of infection with MDROs.

Antimicrobial usage in German acute care hospitals: results of the third national point prevalence survey and comparison with previous national point prevalence surveys

Objectives

Previous point prevalence surveys (PPSs) revealed the potential for improving antimicrobial usage (AU) in German acute care hospitals. Data from the 2016 German national PPS on healthcare-associated infections and AU were used to evaluate efforts in antimicrobial stewardship (AMS).

Methods

A national PPS in Germany was organized by the German National Reference Centre for Surveillance of Nosocomial Infections in 2016 as part of the European PPS initiated by the ECDC. The data were collected in May and June 2016. Results were compared with data from the PPS 2011.

Results

A total of 218 hospitals with 64 412 observed patients participated in the PPS 2016. The prevalence of patients with AU was 25.9% (95% CI 25.6%-26.3%). No significant increase or decrease in AU prevalence was revealed in the group of all participating hospitals. Prolonged surgical prophylaxis was found to be common (56.1% of all surgical prophylaxes on the prevalence day), but significantly less prevalent than in 2011 (P < 0.01). The most frequently administered antimicrobial groups were penicillins plus β-lactamase inhibitors (BLIs) (23.2%), second-generation cephalosporins (12.9%) and fluoroquinolones (11.3%). Significantly more penicillins plus BLIs and fewer second-generation cephalosporins and fluoroquinolones were used in 2016. Overall, an increase in the consumption of broad-spectrum antimicrobials was noted. For 68.7% of all administered antimicrobials, the indication was documented in the patient notes.

Conclusions

The current data reaffirm the points of improvement that previous data identified and reveal that recent efforts in AMS in German hospitals require further intensification.

Impact of psychologically tailored hand hygiene interventions on nosocomial infections with multidrug-resistant organisms: results of the cluster-randomized controlled trial PSYGIENE

Background

Professional hand hygiene compliance represents a multifaceted behaviour with various determinants. Thus, it has been proposed to apply psychological frameworks of behaviour change to its promotion. However, randomized controlled trials of such approaches, which also assess nosocomial infections (NIs), are rare. This study analyses data of the PSYGIENE-trial (PSYchological optimized hand hyGIENE promotion), which has shown improvements in compliance after interventions tailored based on the Health Action Process Approach (HAPA), on rates of NIs with multidrug-resistant organisms (MDROs).

Methods

A parallel-group cluster-randomized controlled trial was conducted on all 10 intensive care units and two hematopoietic stem cell transplantation units at Hannover Medical School, a German tertiary care hospital. Educational training sessions for physicians and nurses (individual-level intervention) and feedback discussions with clinical managers and head nurses (cluster-level) were implemented in 2013. In the “Tailoring”-arm (n = 6 wards), interventions were tailored based on HAPA-components, which were empirically assessed and addressed by behaviour change techniques. As active controls, n = 6 wards received untailored educational sessions of the local “Clean Care is Safer Care”-campaign (Aktion Saubere Hände: “ASH”-arm). From 2013 to 2015 compliance was assessed by observation following the World Health Organization, while alcohol-based hand rub usage (AHRU) and NIs with multidrug-resistant gram-negative bacteria, Methicillin-resistant Staphylococcus aureus or Vancomycin-resistant Enterococcus were assessed following national surveillance protocols. Data were analysed at cluster-level.

Results

In the “Tailoring”-arm, interventions led to a decrease of 0.497 MDRO-infections per 1000 inpatient days from 2013 to 2015 (p = 0.015). This trend was not found in the “ASH”-arm (− 0 . 022 infections; p = 0.899). These patterns corresponded inversely to the trends in compliance but not in AHRU.

Conclusions

While interventions tailored based on the HAPA-model did not lead to a significantly lower incidence rate of MDRO-infections compared to control wards, a significant reduction, compared to baseline, was found in the second follow-up year in the “Tailoring”- but not the "ASH"-arm. This indicates that HAPA-tailored hand hygiene interventions may contribute to the prevention of NIs with MDRO. Further research should focus on addressing compliance by interventions tailored not only to wards, but also leaders, teams, and individuals.

Trial registration

German Clinical Trials Register/International Clinical Trials Registry Platform, DRKS00010960. Registered 19 August 2016-Retrospectively registered, https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00010960. http://apps.who.int/trialsearch/Trial2.aspx?TrialID=DRKS00010960.

Electronic supplementary material

The online version of this article (10.1186/s13756-019-0507-5) contains supplementary material, which is available to authorized users.

Decrease of methicillin resistance in Staphylococcus aureus in nosocomial infections in Germany-a prospective analysis over 10 years

OBJECTIVES

Methicillin resistant Staphylococcus aureus (MRSA) remains an important cause of healthcare-associated infections. Here, we describe the development of methicillin-resistant isolates among nosocomial Staphylococcus aureus (SA) infections in Germany between 2007 and 2016.

METHODS

We analyzed data from the voluntary German national nosocomial Infection Surveillance System. Data on bloodstream infections (BSI) and lower respiratory tract infections (LRTI) were derived from intensive care units (ICU), whereas data on surgical site infections (SSI) were collected from surgical departments (SD). Univariate analysis was performed on trend of proportion, while multivariable logistic regression was performed to identify risk factors for MRSA-infections.

RESULTS

Data of 1218 ICU and 1,556 SD were included. Overall, a decrease in the proportion of MRSA among all nosocomial SA-infections from 32.8% to 20.0% was noted. MRSA decreased from 37.1% to 21.8% (p = 0.01) for BSI, from 38.7% to 19.2% for LTRI (p < 0.01) and. from 21.1% to 7.4% (p < 0.01) in SSI. Logistic regression revealed that SA-infections in Mecklenburg Western-Pomerania were more likely caused by MRSA (Odds ratio (OR): 2.5; 95% CI: 1.7, 3.6).

CONCLUSION

We observed a significant reduction of the proportion of nosocomial Staphylococcus aureus infections due to MRSA in Germany over the course of the last 10 years.

Antibiotic resistance, the 3As and the road ahead

Antibiotic resistance is by far one of the most important health threats of our time. Only a global concerted effort of several disciplines based on the One-Health concept will help in slowing down this process and potentially mitigate the ruin of healthcare we have come to enjoy. In this review, we attempt to summarize the most basic and important topics that serve as good information tools to create Awareness. The Availability of antibiotics or the lack thereof is another significant factor that must be given thought, and finally because antibiotic resistance is a problem that will not go away, it is important to have Alternatives. Together, we have the 3As, essential concepts, in dealing with this growing and complex problem.

Rate and impact of multidrug-resistant organisms in patients with aneurysmal subarachnoid hemorrhage

BACKGROUND

Multidrug-resistant organisms (MDRO) are an increasing problem in critical care medicine. This study describes for the first time the rate and impact of MDRO in patients suffering from aneurysmal subarachnoid hemorrhage (SAH).

METHODS

Anonymized data of SAH patients admitted to our institution from November 2010 to August 2017 were retrospectively reviewed. Patients with microbiological tests positive for MDRO were identified. Screening of MDRO was in consensus with national recommendations.

RESULTS

449 SAH patients were reviewed with 18 patients (prevalence: four MDRO-positive patients per 100 SAH patients) having positive tests for MDRO during their hospital stay. The prevalence upon admission was 1.3 MDRO-positive patients per 100 patients. The acquisition rate was 1.1 MDRO-positive patients per 1000 hospital days. Patients positive for an MDRO had a significantly extended length of stay in intensive care (mean ± SD 26.7 ± 13.0 versus 18.4 ± 11.7 days, p = 0.004) and in hospital (mean ± SD 33.9 ± 12.4 versus 24.4 ± 12.6 days, p = 0.002). MDRO detection was associated with a significant prolonged duration of mechanical ventilation (median (IQR) 254.0 (14.9-632.8) versus 37.5 (3.3-277.0) hours, p = 0.02). There was no statistically significant effect on the Glasgow Outcome Scale (GOS) at discharge and at follow-up after 164.4 ± 113.0 days.

CONCLUSIONS

MDRO positivity is present in 4% of aneurysmal SAH patients. It seems to be associated with a prolonged length of stay and prolonged duration of mechanical ventilation. The importance of infection control standards in neurointensive care units is emphasized.

Wagenlehner F, Zimmer KP, Chakraborty T. Treatment Options for Carbapenem- Resistant Gram-Negative Infections

BACKGROUND

Rates of colonization and infection with carbapenem-resistant Gram-negative pathogens are on the rise, particularly in southeastern European countries, and this is increasingly true in Germany as well. The organisms in question include enterobacteriaceae such as Klebsiella pneumoniae and Escherichia coli and non-fermenting bacteria such as Pseudomonas aeruginosa and Acinetobacter baumannii. As the carbapenems have been the gold standard to date for the systemic treatment of serious infections with Gram-negative bacteria, carbapenem resistance presents new and difficult challenges in therapeutic decision-making, particularly because of the high frequency of coresistance.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed and on other applicable literature.

RESULTS

Multiresistant Gram-negative (MRGN) pathogens are classified in Germany according to their resistance to four different classes of antibiotics; fluoroquinolones, piperacillin, third-generation cephalosporins, and carbapenems. Quadruple MRGN pathogens are resistant to all four groups, triple MRGN pathogens to three of them. There are a number of therapeutic alternatives to carbapenems that can be applied with the aid of sensitive microbiological and/or molecular genetic testing. The following antibiotics are often the only ones that can be used to treat quadruple MRGN pathogens: colistin, aminoglycosides, tigecycline, fosfomycin, ceftazidime/avibactam, and ceftolozan/tazobactam. Carbapenems, too, may still be an option in certain situations. There is also evidence that combinations of antibiotics against which the pathogen is resistant individually can some- times be a valid treatment option; these include combinations of colistin with one or two carbapenems.

CONCLUSION

The treatment of severe infection with carbapenem-resistant pathogens should be individualized and carried out in an interdisciplinary framework, in consideration of antibiotic pharmacokinetics and pharmacodynamics in each case. The treat- ment options are based on evidence from in vitro studies, retrospective studies, and case series, which must be interpreted with caution. Randomized clinical trials are needed to test each of the various combined approaches.