Calculated parenteral initial treatment of bacterial infections: Introduction and antibiotics

This is the first chapter of the guideline "Calculated initial parenteral treatment of bacterial infections in adults - update 2018" in the 2nd updated version. The German guideline by the Paul-Ehrlich-Gesellschaft für Chemotherapie e.V. (PEG) has been translated to address an international audience. This guideline is a revision of the recommendations published in 2010, taking into account recent substances and studies. As with previous revisions, the current situation of pathogen resistance and the results of new clinical trials are considered. The results are the present recommendations for parenteral calculated initial therapy of bacterial infections in adults. If several treatment options are mentioned, they are not always equivalent in their spectrum of microbiological activity. Therapeutic alternatives offer the opportunity to consider pathogen epidemiology, to avoid antibiotic intolerances or to escalate or de-escalate treatment in a manner suited to the situation. This article describes the different therapy options.

[S2k guidelines of the PEG on calculated parenteral initial treatment of bacterial diseases in adults : Focussed summary and supplementary information on antibiotic treatment of critically ill patients]

In January 2018 the recent revision of the S2k guidelines on calculated parenteral initial treatment of bacterial diseases in adults-update 2018 (Editor: Paul Ehrlich Society for Chemotherapy, PEG) was realized. It is a helpful tool for the complex infectious disease setting in an intensive care unit. The present summary of the guidelines focuses on the topics of anti-infective agents, including new substances, pharmacokinetics and pharmacodynamics as well as on microbiology, resistance development and recommendations for calculated drug therapy in septic patients. As in past revisions the recent resistance situation and results of new clinical studies are considered and anti-infective agents are summarized in a table.

[In-vitro activity of mecillinam against urine isolates of Escherichia coli from outpatient departments in Germany]

National and international guidelines recommend fosfomycin trometamol, nitrofurantoin, nitroxoline, and pivmecillinam as first-line agents for the treatment of acute uncomplicated cystitis. Escherichia coli is by far the leading cause of community-acquired urinary tract infections. Pivmecillinam (X-SYSTO^®) is an oral prodrug of mecillinam, a penicillin derivative that was reintroduced to the German market in March 2016. This study aimed to investigate the proportion of mecillinam-resistant strains among E. coli isolates prior to the introduction of X-SYSTO^® in Germany.An in-vitro study was carried out to determine the minimal inhibitory concentrations (MICs) of mecillinam against 494 urine isolates of E. coli (including multidrug-resistant strains). Isolates were obtained from outpatients and collected in 25 laboratories between October and December 2013. MIC breakpoints defined by the European Committee on Antimicrobial Susceptibility Testing (EUCAST) were applied for classifying the bacterial isolates as mecillinam-susceptible (MIC ≤ 8 mg/l) or resistant (MIC > 8 mg/l).The concentrations of mecillinam needed to inhibit 50 % and 90 % of the test isolates were 1 and 4 mg/l, respectively, for isolates displaying the extended spectrum β-lactamase phenotype, and 0.25 and 4 mg/l, respectively, for the remaining isolates. Overall, 98 % of the isolates were found to be mecillinam-susceptible (MIC ≤ 8 mg/l), and 2 % were found to be resistant (MIC > 8 mg/l).These findings support the recommendation to regard pivmecillinam as a first-line option for the treatment of acute uncomplicated cystitis.

Temporal trends of the in vitro activity of tigecycline and comparator antibiotics against clinical aerobic bacterial isolates collected in Germany, 2006-2014: results of the Tigecycline Evaluation and Surveillance Trial (TEST)

Given the rapidly changing landscape of antimicrobial resistance, continuous monitoring of antimicrobial susceptibility in clinically relevant bacterial isolates plays an important role in the management of infectious diseases. The Tigecycline Evaluation and Surveillance Trial (TEST) is an ongoing worldwide surveillance programme monitoring the in vitro activity of tigecycline and a panel of representative comparator antibiotics. We report longitudinal susceptibility data on a large set of isolates (n=36,044) from clinically significant bacterial species collected in 25 microbiological laboratories from 2006 to 2014. Trends include a strong increase of carbapenem and levofloxacin resistance in Acinetobacter spp., and smaller increasing rates of ESBL-producing Escherichia coli and vancomycin-resistant enterococci. Across the reporting period, the tigecycline minimum inhibitory concentrations (MICs) at which 50% and 90% of isolates were inhibited remained stable and susceptibility rates were consistently high (93–100%) for all bacterial species.

Occurrence of multidrug resistance to oral antibiotics among Escherichia coli urine isolates from outpatient departments in Germany: extended-spectrum β-lactamases and the role of fosfomycin

The in vitro activities of fosfomycin and seven other antibiotics commonly used for oral treatment of urinary tract infections (UTIs) were evaluated for 499 Escherichia coli isolated from urine samples during a nationwide laboratory-based surveillance study in 2010. Overall, the highest resistance rates were found for amoxicillin (42.9%), followed by amoxicillin/clavulanic acid (32.7%), trimethoprim/sulfamethoxazole (SXT) (30.9%), ciprofloxacin (19.8%), cefuroxime (10.0%), cefpodoxime (8.6%) and cefixime (8.2%). One-half of the isolates (n=252; 50.5%) were fully susceptible to the eight drugs, whilst only 6 strains (1.2%) were resistant to fosfomycin. Combined resistance to amoxicillin, cefuroxime, ciprofloxacin and SXT was detected in 29 isolates (5.8%). Moreover, 40 isolates (8.0%) produced an extended-spectrum β-lactamase (ESBL), including CTX-M-type ESBLs detected in 39/40 isolates (97.5%) and a TEM-52 ESBL in 1 strain (2.5%). The predominant CTX-M-type ESBL was CTX-M-15 (27/39; 69.2%). Of the 27 CTX-M-15 producers, 19 (70.4%) belonged to the clonal lineage E. coli O25b-ST131. All but one ESBL-producing strains were fosfomycin-susceptible. In view of the emergence of multidrug resistance to standard oral antibiotics, these data support that oral fosfomycin (trometamol salt) may represent a valuable option in the treatment of uncomplicated UTIs.

Antimicrobial susceptibility and molecular epidemiology of Neisseria gonorrhoeae in Germany

Antimicrobial drug resistance in Neisseria gonorrhoeae has become an increasing public health problem. Hence, surveillance of resistance development is of crucial importance to implement adequate treatment guidelines. Data on the spread of antibiotic resistance among gonococcal isolates in Germany, however, is scarce. In a resistance surveillance study conducted by the Paul Ehrlich Society for Chemotherapy between October 2010 and December 2011, 23 laboratories all over Germany were requested to send N. gonorrhoeae isolates to the study laboratory in Frankfurt am Main. Species verification was performed biochemically using ApiNH and with Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS). Antimicrobial susceptibility testing was performed using the Etest method. For molecular epidemiological analysis, N. gonorrhoeae strains were genotyped by means of N. gonorrhoeae multi-antigen sequence typing. A total of 213 consecutive gonococcal isolates were analyzed in this nationwide study. Applying EUCAST breakpoints, high resistance rates were found for ciprofloxacin (74%) and tetracycline (41%). Penicillin non-susceptibility was detected in 80% of isolates. The rate of azithromycin resistance was 6%, while all strains were susceptible to spectinomycin, cefixime, and ceftriaxone. Molecular typing of gonococcal isolates revealed a great heterogeneity of 99 different sequence types (ST), but ST1407 predominated (n=39). This is the first comprehensive German multi-centre surveillance study on antibiotic susceptibility and molecular epidemiology of N. gonorrhoeae with implications for antibiotic choice for treatment of gonorrhoea. The World Health Organization supports the concept that an efficacious treatment of gonorrhoea results in at least 95% of infections being cured. Accordingly, as spectinomycin is not available on the German market, only the third generation cephalosporins cefixime and ceftriaxone are regarded as valuable drugs for empirical treatment of gonorrhoea in Germany.

[Surveillance of antibiotic consumption : clarification of the "definition of data on the nature and extent of antibiotic consumption in hospitals according to § 23 paragraph 4 sentence 2 of the IfSG"]

According to § 23 paragraph 4 of the German Infection Prevention Act (IfSG; July 2011), hospitals and clinics for ambulatory surgery are obliged to establish a continuous monitoring system of antibiotic consumption. This is aimed at contributing to an optimization of antibiotic prescription practices in order to confine the development and spread of resistant pathogens. The general requirements (restricted to hospitals) on the method and extent of data collection are provided by the national public health institution after discussion with representatives of various professional societies (Robert Koch-Institut, Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 59, 2013). The article aims to clarify these specifications and to provide background details. In agreement with national and European surveillance systems, the Anatomical Therapeutic Chemical (ATC)/Defined Daily Dose (DDD) classification system recommended by the WHO should be used as reference standard. Antibiotic consumption should be expressed as the number of DDDs per 100 patient days and per 100 admissions. The categories of antimicrobials and hospital organizational units to be monitored and the time intervals in which analyses should be conducted are determined. Furthermore, various approaches of data assessment are described.

Urinary concentrations and antibacterial activities of nitroxoline at 250 milligrams versus trimethoprim at 200 milligrams against uropathogens in healthy volunteers

Because of the increasing bacterial resistance of uropathogens against standard antibiotics, such as trimethoprim (TMP), older antimicrobial drugs, such as nitroxoline (NTX), should be reevaluated. This randomized crossover study investigated the urinary concentrations of parent drugs and their metabolites and their antibacterial activities (urinary inhibitory titers [UITs] and urinary bactericidal titers [UBTs]) against uropathogens at three different urinary pH values within 24 h in six healthy volunteers after a single oral dose of NTX at 250 mg versus TMP at 200 mg. In three additional volunteers, urinary bactericidal kinetics (UBK) were studied after oral administration of NTX at 250 mg three times a day. The mean urinary concentrations of NTX and NTX sulfate in 24 h were 0.012 to 0.507 mg/liter and 0.28 to 27.83 mg/liter, respectively. The mean urinary concentrations of TMP were 18.79 to 41.59 mg/liter. The antibacterial activity of NTX was higher in acidic urine than in alkaline urine, and that of TMP was higher in alkaline urine than in acidic urine. The UITs and UBTs of NTX were generally lower than those of TMP except for a TMP-resistant Escherichia coli strain, for which NTX showed higher UITs/UBTs than did TMP. UBK showed mainly bacteriostatic activity of NTX in urine. NTX exhibits mainly bacteriostatic activity and TMP also shows bactericidal activity in urine against susceptible strains. NTX is a more active antibacterial in acidic urine, and TMP is more active in alkaline urine. The cumulative effects of multiple doses or inhibition of bacterial adherence could not be evaluated. (This study has been registered at EudraCT under registration no. 2009-015631-32.).

[Multiresistant pathogens--a challenge for clinicians]

Gram-negative pathogens are currently isolated frequently in invasive nosocomial infections and give rise to major therapeutic problems due to their resistance pattern. Metaanalyses of randomised controlled studies have demonstrated that an antibiotic combination treatment is not indicated in many cases. However, in critically ill patients (septic shock) and also in immunocompromised patients with previous intensive care as well as broad spectrum antibiotic treatment, a combination of antibiotics is recommended. This therapy should be based on the source of the infection, on local resistance data, on antibiotic pretreatment, on basic diseases of the patient and on current liver and renal functions. The start of therapy should be as fast as possible after collection of optimal materials for microbiological analysis. Dosage of selected antibiotics should be based on rational pharmacokinetic and pharmacodynamic parameters. A de-escalation of antibiotics is strongly recommended in all international guidelines based on the microbiological results and the clinical response of the patient. New antibiotics or therapeutic strategies against multiresistant Gram-negative pathogens will not be available in the next 5 to 10 years; therefore, it is absolute mandatory to use the currently still effective antibiotics, like carbapenems and polymyxins, very rationally and restrictively.

Molecular epidemiology of Acinetobacter baumannii and Acinetobacter nosocomialis in Germany over a 5-year period (2005-2009)

To investigate the species distribution within the Acinetobacter calcoaceticus-Acinetobacter baumannii complex and the molecular epidemiology of A. baumannii and Acinetobacter nosocomialis, 376 Acinetobacter isolates were collected prospectively from hospitalized patients at 15 medical centres in Germany during three surveillance studies conducted over a 5-year period. Species identification was performed by molecular methods. Imipenem minimum inhibitory concentrations (MIC) were determined by broth microdilution. The prevalence of the most common carbapenemase-encoding genes was investigated by oxacillinase (OXA) -multiplex polymerase chain reaction (PCR). The molecular epidemiology was investigated by repetitive sequence-based PCR (rep-PCR; DiversiLab™). Acinetobacter pittii was the most prevalent Acinetobacter species (n = 193), followed by A. baumannii (n = 140), A. calcoaceticus (n = 10) and A. nosocomialis (n = 8). The majority of A. baumannii was represented by sporadic isolates (n = 70, 50%) that showed unique rep-PCR patterns, 25 isolates (18%) clustered with one or two other isolates, and only 45 isolates (32%) belonged to one of the previously described international clonal lineages. The most prevalent clonal lineage was international clone (IC) 2 (n = 34) and IC 1 (n = 6). According to CLSI, 25 A. baumannii isolates were non-susceptible to imipenem (MIC ≥ 8 mg/L), all of which produced an OXA-58-like or OXA-23-like carbapenemase. The rate of imipenem susceptibility among A. baumannii isolates decreased from 96% in 2005 to 76% in 2009. All other Acinetobacter isolates were susceptible to imipenem. The population structure of carbapenem-susceptible A. baumannii in Germany is highly diverse. Imipenem non-susceptibility was strongly associated with the clonal lineages IC 2 and IC 1. These data underscore the high clonality of carbapenem-resistant A. baumannii isolates.

Susceptibility of clinical isolates of frequently encountered bacterial species to tigecycline one year after the introduction of this new class of antibiotics: results of the second multicentre surveillance trial in Germany (G-TEST II, 2007)

Tigecycline, a broad-spectrum antibiotic for parenteral use, was introduced in Germany in May 2006. In the G-TEST-II trial, the susceptibility of isolates, recovered in 2007 from hospitalised patients in 15 centres, was assessed against tigecycline and comparators. Susceptibility tests were performed by the microdilution procedure. This study reports on the susceptibility of the isolates of 16 bacterial species and compares the results with those of a trial (G-TEST I) conducted prior to the introduction of tigecycline. Between 2005 and 2007, tigecycline retained activity against Gram-positive and Gram-negative organisms. By contrast, the rate of vancomycin-resistant strains among Enterococcus faecium isolates almost doubled. Moreover, an increase in resistance to broad-spectrum beta-lactams and fluoroquinolones was observed for members of the family Enterobacteriaceae. Against a background of a steadily rising number of pathogens that are resistant to various antibiotic classes, tigecycline represents an important treatment option.

Susceptibility of common aerobic pathogens to tigecycline: results of a surveillance study in Germany

Tigecycline is a novel antimicrobial agent for parenteral use encompassing a broad spectrum of bacterial pathogens, including multi-resistant organisms. Here, we report the results of the first nationwide surveillance trial that was conducted in order to evaluate the susceptibility of bacterial isolates to tigecycline in a European country prior to its clinical use. A total of 2,610 Gram-positive and Gram-negative organisms recovered from hospitalized patients were tested. Minimum inhibitory concentrations (MICs) were determined using the microdilution method. All enterococci, staphylococci (including methicillin-resistant Staphylococcus aureus; MRSA), and streptococci tested were tigecycline-susceptible, except one isolate of Staphylococcus haemolyticus. Among the Gram-negative bacteria, 100% of the Escherichia coli isolates (including extended spectrum beta-lactamase [ESBL]-producers) were tigecycline-susceptible, while about 10% of the Enterobacter cloacae and Klebsiella pneumoniae isolates were resistant. Based on the results of this surveillance study, tigecycline may represent a suitable option most notably for the empiric treatment of bacterial mixed infections, including in clinical situations in which multi-resistant organisms are suspected.

Bactericidal activity of daptomycin, vancomycin, teicoplanin and linezolid against Staphylococcus aureus, Enterococcus faecalis and Enterococcus faecium using human peak free serum drug concentrations

The bactericidal activities of daptomycin, vancomycin, teicoplanin and linezolid at human peak free serum concentrations (C(max,free)) were determined against Staphylococcus aureus (one methicillin-susceptible and two methicillin-resistant strains), Enterococcus faecalis and Enterococcus faecium (one vancomycin-susceptible and one vancomycin-resistant strain of each). Daptomycin was rapidly bactericidal against 7/7 strains at C(max,free) of 22.0 mg/L (corresponding to 63% protein binding) and against 3/7 strains at 4.8 mg/L (corresponding to 92% protein binding). Vancomycin (18.0 mg/L) was bactericidal against only two strains. Both teicoplanin (4.5 mg/L) and linezolid (10.4 mg/L) were consistently bacteriostatic. Daptomycin is a useful option for the treatment of Gram-positive infections owing to its strong bactericidal activity.

Surveillance of linezolid resistance in Germany, 2001–2002

A surveillance study was performed throughout Germany from November 2001 to June 2002 to assess the prevalence of linezolid-resistant isolates among Gram-positive bacteria from routine susceptibility data and to compare the in-vitro activity of linezolid to that of other antibacterial agents. Each of 86 laboratories provided routine susceptibility data for 100 consecutive isolates. Most laboratories (c. 60%) used the disk diffusion test. Laboratories were also requested to send a representative sample of their isolates, as well as all isolates reported as intermediate or resistant to linezolid, to a reference laboratory for MIC determination. Susceptibility data for 8594 isolates were evaluated. Sites of infection were skin and soft tissue (29.9%), upper and lower respiratory tract (19.1%), foreign body or catheter (10.5%), or urinary tract (9.8%). Routine linezolid susceptibility data were reported for 6433 isolates. The prevalence of linezolid resistance, as reported to the clinician, was 0.4% in Staphylococcus aureus, 0.3% in Staphylococcus epidermidis, 2.9% in Enterococcus faecalis, 2.3% in Enterococcus faecium, 1.4% in Streptococcus pyogenes and 2.9% in Streptococcus agalactiae. Linezolid resistance was not detected in Streptococcus pneumoniae or in viridans group streptococci. Sixty-nine of 115 isolates reported as intermediate or resistant to linezolid were retested, but none was resistant to linezolid. Linezolid exhibited excellent in-vitro activity against representative isolates of the six most frequently encountered species (MIC90, 1-2 mg/L). The prevalence of resistance to linezolid was very low in Germany. Organisms reported as linezolid-resistant should be retested, either in the same laboratory with an alternative method or in a reference laboratory.

Activities of various β-lactams and β-lactam/β-lactamase inhibitor combinations against Acinetobacter baumannii and Acinetobacter DNA group 3 strains

Acinetobacter baumannii and Acinetobacter DNA group 3 are members of the so-called A. calcoaceticus-A. baumannii complex and are important nosocomial pathogens. Multiresistance in these organisms is increasingly frequent, and alternative treatment options are needed. The beta-lactamase inhibitors clavulanate, sulbactam and tazobactam have intrinsic activity against Acinetobacter strains. In the present study, broth microdilution was used to assess the in-vitro activities of currently available beta-lactam/beta-lactamase inhibitor combinations and sulbactam alone against 469 Acinetobacter isolates (A. baumannii, n=395; Acinetobacter DNA group 3, n=74) collected from various laboratories in Germany. Fixed concentrations and fixed ratios of beta-lactamase inhibitors were used. Sulbactam-containing combinations (susceptibility rates of 90.4-92.7% for A. baumannii and 97.3-100% for Acinetobacter DNA group 3) and sulbactam alone were superior to clavulanate- and tazobactam-containing combinations. The activity of sulbactam-containing combinations against members of the A. calcoaceticus-A. baumannii complex was conferred exclusively by the intrinsic activity of the beta-lactamase inhibitor and did not result from enhanced beta-lactam activity. Testing with the inhibitor added at a fixed ratio of inhibitor to beta-lactam appeared to give more reliable results than testing at a fixed concentration of the inhibitor. Resistance to carbapenems (0.3%) remains low in Germany.

High prevalence of the ermB gene among erythromycin-resistant streptococcus pneumoniae isolates in Germany during the winter of 2000-2001 and in vitro activity of telithromycin

Of 595 isolates of Streptococcus pneumoniae from outpatients with respiratory tract infections, collected from 17 microbiology laboratories, 14.1% were resistant to erythromycin. Eighty-three erythromycin-resistant isolates were genetically analyzed, 83.1% of which harbored the ermB gene. Only four isolates (4.8%) harbored the mefA gene. Telithromycin exhibited potent activity against all isolates.

Prevalence of mupirocin resistance in clinical isolates of Staphylococcus aureus and Staphylococcus epidermidis: results of the Antimicrobial Resistance Surveillance Study of the Paul-Ehrlich-Society for Chemotherapy, 2001

A multicentre surveillance study comprising 26 laboratories located in Austria, Germany, and Switzerland was carried out in November 2001. A total of 787 isolates of Staphylococcus aureus and 456 isolates of Staphylococcus epidermidis mainly recovered from hospitalised patients, were tested. MICs for mupirocin were determined using the broth microdilution procedure. Breakpoints were < or = 4 mg/l (susceptible), 8-256 mg/l (low-level resistance) and > or = 512 mg/l (high-level resistance). Rates of low- and high-level resistances were 2.9 and 0.9% in S. aureus, and 9.4 and 3.3% in S. epidermidis, respectively. Mupirocin resistance was almost exclusively observed in oxacillin-resistant isolates of S. aureus (MRSA) and S. epidermidis (MRSE). High-level mupirocin resistance was detected in 3.1 and 4.5% of MRSA and MRSE, respectively.