Safety and efficacy of tigecycline in treatment of skin and skin structure infections: results of a double-blind phase 3 comparison study with vancomycin-aztreonam

Tigecycline-Containing Regimens and Multi Drug-Resistant Acinetobacter baumannii: A Systematic Review and Meta-Analysis

Introduction: The use of tigecycline (TG) for the treatment of Acinetobacter baumannii is controversial. In this systematic review and meta-analysis, we aimed to better explore the safety and efficacy of TG for the treatment of multi drug-resistant (MDR) Acinetobacter. Methods: We searched PubMed/MEDLINE, Scopus, Cochrane Central, and Web of Science to identify studies reporting the clinical and microbiological efficacy and safety of regimens containing TG in patients with drug susceptibility testing (DST)-confirmed MDR A. baumannii, published until December 30, 2022. Observational studies were included if they reported clinical and microbiological efficacy of TG-based regimens. The Newcastle-Ottawa Scale (NOS) and Joana Briggs Institute (JBI) critical appraisal tool were used to assess the quality of included studies. Results: There were 30 observational studies, of which 19 studies were cohort and 11 studies were single group studies. Pooled clinical response and failure rates in the TG-containing regimens group were 58.1 (95% confidence interval [CI] 49.2-66.6) and 40.2 (95% CI 31.1-50.0), respectively. The pooled microbiological response rate was 32.1 (95% CI 19.8-47.5), and the pooled all-cause mortality rate was 41.1 (95% CI 34.1-48.4). Pooled clinical response and failure rates in the colistin-based regimens group were 52.7 (42.7-62.5) and 43.1 (33.1-53.8), respectively. The pooled microbiological response rate was 42.9 (16.2-74.5), and the pooled all-cause mortality rate was 34.3 (26.1-43.5). Conclusions: According to our results, the efficacy of the TG-based regimen is the same as other antibiotics. However, our study showed a high mortality rate and a lower rate of microbiological eradication for TG compared with colistin-based regimen. Therefore, our study does not recommend it for the treatment of MDR A. baumannii. However, this was a prevalence meta-analysis of observational studies, and for better conclusion experimental studies are required.

Protective role of resveratrol against VCM-induced hepatotoxicity in male wistar rats

Background: Vancomycin is a glycopeptide antibiotic with a high risk of acute liver injury. Resveratrol is believed to protect the liver against toxicity. Aim: To investigate the ability of resveratrol to attenuate vancomycin-induced liver toxicity in rats injected with vancomycin. Method: Twenty-four adult male Wistar rats were distributed into three groups. The control group received only a vehicle, while the treated group received either vancomycin 200 (mg/kg, i. p.) only or vancomycin (200 mg/kg, i. p.) with resveratrol (20 mg/kg, oral gavage). All groups received their dose once daily for 7 days. Hepatic damage was assessed by measuring biochemical parameter levels in serum, aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH). Also, antioxidants and inflammation biomarkers such as Interleukin-6 (IL-6), malondialdehyde (MDA), nitric oxide (NO), and glutathione (GSH) were measured. Furthermore, the vancomycin-induced pathological changes in the liver were evaluated by histopathological studies. Results: In the vancomycin-treated group, hepatic serum biomarkers such as AST, ALT, ALP, IL-6, and MDA were elevated, while NO and GSH were depleted. However, resveratrol co-treatment with vancomycin prevented the elevation of AST, ALT, ALP, IL-6, and MDA and it protected the liver from NO and GSH depletion. Also, regarding vancomycin-induced degeneration of hepatocytes, resveratrol co-treatment with vancomycin prevented such degeneration and improved mononuclear cells in the liver. Conclusion: The results showed that oral administration of resveratrol has a significant hepatoprotective effect against vancomycin-induced hepatotoxicity.

Re-establishing the utility of tetracycline-class antibiotics for current challenges with antibiotic resistance

The progressive increase in antibiotic resistance in recent decades calls for urgent development of new antibiotics and antibiotic stewardship programs to help select appropriate treatments with the goal of minimising further emergence of resistance and to optimise clinical outcomes. Three new tetracycline-class antibiotics, eravacycline, omadacycline, and tigecycline, have been approved within the past 15 years, and represent a new era in the use of tetracyclines. These drugs overcome the two main mechanisms of acquired tetracycline-class resistance and exhibit a broad spectrum of in vitro activity against gram-positive, gram-negative, anaerobic, and atypical pathogens, including many drug-resistant strains. We provide an overview of the three generations of tetracycline-class drugs, focussing on the efficacy, safety, and clinical utility of these three new third-generation tetracycline-class drugs. We also consider various scenarios of unmet clinical needs where patients might benefit from re-engagement with tetracycline-class antibiotics including outpatient treatment options, patients with known β-lactam antibiotic allergy, reducing the risk of Clostridioides difficile infection, and their potential as monotherapy in polymicrobial infections while minimising the risk of any potential drug-drug interaction. KEY MESSAGESThe long-standing safety profile and broad spectrum of activity of tetracycline-class antibiotics made them a popular choice for treatment of various bacterial infections; unfortunately, antimicrobial resistance has limited the utility of the early-generation tetracycline agents.The latest generation of tetracycline-class antibiotics, including eravacycline, tigecycline, and omadacycline, overcomes the most common acquired tetracycline resistance mechanisms.Based on in vitro characteristics and clinical data, these newer tetracycline agents provide an effective antibiotic option in the treatment of approved indications in patients with unmet clinical needs - including patients with severe penicillin allergy, with renal or hepatic insufficiency, recent Clostridioides difficile infection, or polymicrobial infections, and those at risk of drug-drug interactions.

Efficacy and safety of optional parenteral antimicrobial therapy for complicated skin and soft tissue infections: A systematic review and Bayesian network meta-analysis

BACKGROUND

Skin and soft tissue infections (SSTIs) carry significant economic burden, as well as morbidity and mortality, especially when caused by methicillin-resistant Staphylococcus aureus. This study aims to investigate the efficacy and safety of optional antimicrobial therapy for the treatment of complicated SSTIs (cSSTIs).

METHODS

We searched PubMed, Medline (Via Ovid SP), Embase (Via Ovid SP), and the Cochrane Central Register of Controlled Trials from their inception to March 22, 2021 for randomized controlled trials (RCTs) that studied the use of optional antimicrobial therapy for cSSTIs. Citations' screening, study selection, data extraction, and risk of bias assessment were independently performed by 2 authors. The primary outcomes were clinical and microbiological treatment success, and adverse events (AEs) were also assessed.

RESULTS

A total of 48 trials covering 24,381 patients assessing 20 types of antimicrobial treatment modalities were included. Overall, omadacycline was associated with the highest beneficial effect on clinical and microbiological treatment success and with the largest rank probability based on surface under the cumulative ranking curve values, avarofloxacin was closely followed. Both had, however, omadacycline was related to moderately safety profiles. Lefamulin ranked as the best option was associated with the lowest risk of severe AEs. Subgroup analysis showed similar results. The quality of primary outcomes was moderate to low.

CONCLUSIONS

The use of omadacycline was associated with higher rates of clinical and microbiological treatment success for the treatment of cSSTIs, with a relative low risk of AEs. Due to the limitations of the included RCTs, high-quality and well-designed RCTs are needed to further confirm the results.

Diagnosis and management of infections caused by multidrug-resistant bacteria: guideline endorsed by the Italian Society of Infection and Tropical Diseases (SIMIT), the Italian Society of Anti-Infective Therapy (SITA), the Italian Group for Antimicrobial Stewardship (GISA), the Italian Association of Clinical Microbiologists (AMCLI) and the Italian Society of Microbiology (SIM)

Management of patients with infections caused by multidrug-resistant organisms is challenging and requires a multidisciplinary approach to achieve successful clinical outcomes. The aim of this paper is to provide recommendations for the diagnosis and optimal management of these infections, with a focus on targeted antibiotic therapy. The document was produced by a panel of experts nominated by the five endorsing Italian societies, namely the Italian Association of Clinical Microbiologists (AMCLI), the Italian Group for Antimicrobial Stewardship (GISA), the Italian Society of Microbiology (SIM), the Italian Society of Infectious and Tropical Diseases (SIMIT) and the Italian Society of Anti-Infective Therapy (SITA). Population, Intervention, Comparison and Outcomes (PICO) questions about microbiological diagnosis, pharmacological strategies and targeted antibiotic therapy were addressed for the following pathogens: carbapenem-resistant Enterobacterales; carbapenem-resistant Pseudomonas aeruginosa; carbapenem-resistant Acinetobacter baumannii; and methicillin-resistant Staphylococcus aureus. A systematic review of the literature published from January 2011 to November 2020 was guided by the PICO strategy. As data from randomised controlled trials (RCTs) were expected to be limited, observational studies were also reviewed. The certainty of evidence was classified using the GRADE approach. Recommendations were classified as strong or conditional. Detailed recommendations were formulated for each pathogen. The majority of available RCTs have serious risk of bias, and many observational studies have several limitations, including small sample size, retrospective design and presence of confounders. Thus, some recommendations are based on low or very-low certainty of evidence. Importantly, these recommendations should be continually updated to reflect emerging evidence from clinical studies and real-world experience.

Efficacy and safety of delafloxacin, ceftaroline, ceftobiprole, and tigecycline for the empiric treatment of acute bacterial skin and skin structure infections: A network meta-analysis of randomized controlled trials

Background

Method

Results

Conclusion

The Development of Third-Generation Tetracycline Antibiotics and New Perspectives

The tetracycline antibiotic class has acquired new valuable members due to the optimisation of the chemical structure. The first modern tetracycline introduced into therapy was tigecycline, followed by omadacycline, eravacycline, and sarecycline (the third generation). Structural and physicochemical key elements which led to the discovery of modern tetracyclines are approached. Thus, several chemical subgroups are distinguished, such as glycylcyclines, aminomethylcyclines, and fluorocyclines, which have excellent development potential. The antibacterial spectrum comprises several resistant bacteria, including those resistant to old tetracyclines. Sarecycline, a narrow-spectrum tetracycline, is notable for being very effective against Cutinebacterium acnes. The mechanism of antibacterial action from the perspective of the new compound is approached. Several severe bacterial infections are treated with tigecycline, omadacycline, and eravacycline (with parenteral or oral formulations). In addition, sarecycline is very useful in treating acne vulgaris. Tetracyclines also have other non-antibiotic properties that require in-depth studies, such as the anti-inflammatory effect effect of sarecycline. The main side effects of modern tetracyclines are described in accordance with published clinical studies. Undoubtedly, this class of antibiotics continues to arouse the interest of researchers. As a result, new derivatives are developed and studied primarily for the antibiotic effect and other biological effects.

Efficacy and safety of tigecycline in treatment of pneumonia caused by MDR Acinetobacter baumannii: a systematic review and meta-analysis

BACKGROUND

Use of tigecycline in treating MDR Acinetobacter baumannii (MDRAB) remains controversial.

OBJECTIVES

To comprehensively assess the safety and efficacy of tigecycline in pneumonia caused by Acinetobacter baumannii.

METHODS

PubMed, Embase, Web of Science and Cochrane library databases were searched up to 12 March 2019. Studies were included if they compared tigecycline-based regimens with other antibiotic regimens for treating AB pulmonary infections and we pooled the clinical outcomes, microbiological response, adverse events or mortality.

RESULTS

One prospective study and nine retrospective studies were included in this meta-analysis. The results showed similar clinical cure rates (OR = 1.04, 95% CI = 0.60-1.81; P = 0.89) and mortality rates (OR = 1.11, 95% CI = 0.65-1.89; P = 0.71) comparing tigecycline groups with the control groups. However, a significantly lower microbiological eradication rate was found in the tigecycline groups (OR = 0.43, 95% CI = 0.27-0.66; P = 0.0001). Incidence of nephrotoxicity in tigecycline-based regimens was significantly lower than in colistin-based regimens (OR = 0.34, 95% CI = 0.16-0.74, I2 = 35%, P = 0.006). There were no randomized controlled trials (RCTs) included; incomplete safety data and regional bias caused by the majority of the studies originating in China are the main limitations of this meta-analysis.

CONCLUSIONS

Tigecycline can be used for treating MDRAB pulmonary infections owing to efficacy similar to that of other antibiotics. Moreover, tigecycline did not show a higher risk of mortality. Considering the lower microbiological eradication rate for tigecycline, which is likely to induce antimicrobial resistance, well-designed RCTs for high-dose tigecycline in treating pneumonia caused by AB are still needed.

Current Treatment Options for Acute Skin and Skin-structure Infections

Acute bacterial skin and skin-structure infections (ABSSSIs) are a common reason for seeking care at acute healthcare facilities, including emergency departments. Staphylococcus aureus is the most common organism associated with these infections, and the emergence of community-associated methicillin-resistant Staphylococcus aureus (MRSA) has represented a considerable challenge in their treatment. To address this need, a number of new antibiotics have been developed for the treatment of ABSSSIs in the past several years. Most of these agents focus primarily on gram-positive organisms, particularly MRSA; however, there has not been an oral agent that can reliably treat MRSA, as well as relevant gram-negative pathogens. Acute skin infections that involve mixed gram-positive and gram-negative pathogens must also be considered as they can be associated with discordant antimicrobial therapy. Here, I review ABSSSI treatment guidelines in the hospital setting and discuss current and future antibiotic options for treatment of this commonly encountered infection.

A Multicenter Evaluation of Vancomycin-Associated Acute Kidney Injury in Hospitalized Patients with Acute Bacterial Skin and Skin Structure Infections

Background

We sought to determine the real-world incidence of and risk factors for vancomycin-associated acute kidney injury (V-AKI) in hospitalized adults with acute bacterial skin and skin structure infections (ABSSSI).

Methods

Retrospective, observational, cohort study at ten U.S. medical centers between 2015 and 2019. Hospitalized patients treated with vancomycin (≥ 72 h) for ABSSSI and ≥ one baseline AKI risk factor were eligible. Patients with end-stage kidney disease, on renal replacement therapy or AKI at baseline, were excluded. The primary outcome was V-AKI by the vancomycin guidelines criteria.

Results

In total, 415 patients were included. V-AKI occurred in 39 (9.4%) patients. Independent risk factors for V-AKI were: chronic alcohol abuse (aOR 4.710, 95% CI 1.929–11.499), no medical insurance (aOR 3.451, 95% CI 1.310–9.090), ICU residence (aOR 4.398, 95% CI 1.676–11.541), Gram-negative coverage (aOR 2.926, 95% CI 1.158–7.392) and vancomycin duration (aOR 1.143, 95% CI 1.037–1.260). Based on infection severity and comorbidities, 34.7% of patients were candidates for oral antibiotics at baseline and 39.3% had non-purulent cellulitis which could have been more appropriately treated with a beta-lactam. Patients with V-AKI had significantly longer hospital lengths of stay (9 vs. 6 days, p = 0.001), higher 30-day readmission rates (30.8 vs. 9.0%, p < 0.001) and increased all-cause 30-day mortality (5.1 vs. 0.3%, p = 0.024)

Conclusions

V-AKI occurred in approximately one in ten ABSSSI patients and may be largely prevented by preferential use of oral antibiotics whenever possible, using beta-lactams for non-purulent cellulitis and limiting durations of vancomycin therapy.

Electronic supplementary material

The online version of this article (10.1007/s40121-019-00278-1) contains supplementary material, which is available to authorized users.

Busting the Myth of "Static vs Cidal": A Systemic Literature Review

We sought to determine if clinical data validate the dogma that bactericidal antibiotics are more clinically effective than bacteriostatic agents. We performed a systematic literature review of published, randomized, controlled trials (RCTs) that compared a bacteriostatic agent to a bactericidal agent in the treatment of clinical, bacterial infections. Of 56 identified trials published since 1985, 49 found no significant difference in efficacy between bacteriostatic and bactericidal agents. In 6 trials it was found that the bacteriostatic agent was superior to the bactericidal agent in efficacy. Only 1 trial found that the bactericidal agent was superior; in that case, the inferiority of the static agent was explainable by underdosing of the drug based on pharmacokinetic-pharmacodynamic analysis. Thus, virtually all available data from high-quality, RCTs demonstrate no intrinsic superiority of bactericidal compared to bacteriostatic agents. Other drug characteristics such as optimal dosing, pharmacokinetics, and tissue penetration may be more important efficacy drivers.

The optimal duration of treatment for skin and soft tissue infections and acute bacterial skin and skin structure infections

PURPOSE OF REVIEW

To summarize the current finding on SSTIs/ABSSSIs treatment duration.

RECENT FINDINGS

In 2013, the FDA approved the definition of acute bacterial skin and skin structure infections (ABSSSIs). From a clinical point of view, the new definition may present some advantages: the definition of the severity of the disease, the measurement of reduction in lesion size, and effectiveness of treatment primary endpoint at 48-72 h after treatment initiation. New therapeutic options with improved efficacy, safety, and/or pharmacodynamics are available for ABSSSIs and so far, several questions still need to be addressed for the management of these infections, including treatment duration.

SUMMARY

There is a wide variation of duration of antimicrobial treatment in skin and soft tissue infections. Plenty of published data available suggest that we should focus on the early response to shorten duration of treatment, and that the antimicrobial stewardship perspective is extremely helpful in underscoring the need for composite outcomes in clinical practice, as multiple tools are available to increase cost-efficacy, including reduction of treatment changes, early oral switch, early discharge (even from the Emergency Department), outpatient antimicrobial treatment, long-acting antibiotics, and all together, de-escalation treatment strategies.

The safety of treatment options for acute bacterial skin and skin structure infections

INTRODUCTION

Acute bacterial skin and skin-structure infections (ABSSSI) may develop in both in-patients and out-patients, possibly with a severe clinical presentation. Since most phase 3 randomized clinical trials have shown non-inferiority in efficacy across different agents, considerations regarding their different safety profiles inevitably play a crucial role in the everyday choice about which of them should be employed for the treatment of ABSSSI.

AREAS COVERED

In this review, the authors discuss the safety profile of different treatment options for ABSSSI.

EXPERT OPINION

The spread of methicillin-resistant Staphylococcus aureus (MRSA) in the last decades has inevitably influenced the therapeutic approach to ABSSSI. Adequate knowledge of the peculiar toxicity profile of each drug active against MRSA is essential for guiding, monitoring and managing adverse events, in turn reducing any unfavorable impact of toxicity on patients' outcomes. In the next five years, potential toxicity will play a critical role in establishing the best available therapy for each specific patient, together with consideration regarding the possibility of avoiding hospitalization or allowing a switch from intravenous to oral therapy and early discharge.

Influence of age on the clinical efficacy of tigecycline in severely ill patients

OBJECTIVES

The aim of this study was to define the relationship between age and response to tigecycline among patients treated for complicated skin and soft-tissue infections (cSSTIs) and complicated intra-abdominal infections (cIAIs).

METHODS

Pooled data derived from five European observational studies on the use of tigecycline (July 2006-October 2011), either as monotherapy or in combination with other antibiotics, for the treatment of cSSTI or cIAI were used in the analysis.

RESULTS

The total population (N=1782 patients) was divided into three age categories: <65 years (804 patients); 65-80 years (836 patients) and >80 years (139 patients) (data unknown/missing for 3 patients). The overall mean Acute Physiology and Chronic Health Evaluation (APACHE) II score for patients with cSSTI and cIAI was 15.0±7.9 and 16.9±7.6, respectively, and the overall mean Sequential Organ Failure Assessment (SOFA) score was 5.8±3.9 and 7.0±4.2, respectively. Overall, patients with cSSTI and cIAI in the three age groups showed a good response to tigecycline treatment (76.2-80.0% and 69.2-81.1%, respectively) with patients aged ≤80 years showing higher response rates. Patients with cIAI appeared to be at greater risk for all types of adverse events compared with those with cSSTI, particularly in the older age groups.

CONCLUSION

In these real-life studies, tigecycline, either alone or in combination, achieved favourable clinical response rates in all age categories of patients with cSSTIs and cIAIs with a high severity of illness.

Sparing carbapenem usage

Background

Carbapenem resistance in Gram-negative bacteria is increasing in many countries and use of carbapenems and antibiotics to which resistance is linked should be reduced to slow its emergence. There are no directly equivalent antibiotics and the alternatives are less well supported by clinical trials. The few new agents are expensive.

Objectives

To provide guidance on strategies to reduce carbapenem usage.

Methods

A literature review was performed as described in the BSAC/HIS/BIA/IPS Joint Working Party on Multiresistant Gram-negative Infection Report.

Results

Older agents remain active against some of the pathogens, although expectations of broad-spectrum cover for empirical treatment have risen. Education, expert advice on treatment and antimicrobial stewardship can produce significant reductions in use.

Conclusions

More agents may need to be introduced onto the antibiotic formulary of the hospital, despite the poor quality of scientific studies in some cases.

Impact of tigecycline versus imipenem-cilastatin on fibrinogen levels following cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC): a randomized-controlled study

The aim of this prospective, randomized study was to compare the effects of tigecycline and imipenem-cilastatin on fibrinogen levels in patients undergoing cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Patients were empirically randomized to receive tigecycline or imipenem-cilastatin. Fibrinogen levels were measured in both patient groups on days 1, 3, 5 and 8 of antibiotic therapy and 3 days after antibiotic therapy completion. Twenty patients received tigecycline and 22 patients received imipenem-cilastatin . Patients in the tigecycline group had lower mean fibrinogen levels compared to those in the imipenem-cilastatin group on day 3 (4.1 ± 1.2 vs. 5.9 ± 1.3 g/L; p < 0.001), day 5 (3.7 ± 1.2 vs. 6.5 ± 1.1 g/L; p < 0.001), day 8 (3.5 ± 1.3 vs. 5.8 ± 1.6 g/L; p < 0.001), and day 3 after antibiotic completion (4.1 ± 1.4 vs. 6.1 ± 1.6 g/L; p < 0.001). In conclusion, compared to imipenem-cilastatin, tigecycline was associated with a significant decrease in fibrinogen levels, following CRS and HIPEC.

Comparative efficacy and safety of antibiotics used to treat acute bacterial skin and skin structure infections: Results of a network meta-analysis

OBJECTIVE

This NMA compared the efficacy and safety between IV antibiotics that are used in the current standard of care for managing adult patients (≥18 years of age) with ABSSSI.

METHODS

Comparators were chosen on the basis that both direct and indirect comparisons between the interventions of interest could be performed. Outcomes of the analysis were selected on the basis that they are frequently measured and reported in trials involving ABSSSI patients, and only published randomised control trials of any size and duration and with any blinding status were eligible for inclusion in the analysis. The NMA was performed using both a fixed-effect and random-effect model. Efficacy-related endpoints were (1) clinical treatment success and (2) microbiological success at TOC visit. Safety-related endpoints were (1) number of discontinuations due to AEs/SAEs, (2) patients experiencing AEs, (3) patients experiencing SAEs and (4) all-cause mortality.

RESULTS

Study interventions included daptomycin, dalbavancin, linezolid and tigecycline. Vancomycin was the comparator in all studies, except in two where it was linezolid and teicoplanin. The NMA showed that irrespective of patient subgroup, the likelihood of clinical and microbiological success with dalbavancin was statistically similar to the comparators studied. No statistically significant differences were observed between dalbavancin and any of the comparators in the discontinuation rate due to AEs/SAEs. In contrast, dalbavancin was associated with a significantly lower likelihood of experiencing an AE than linezolid, a significantly lower likelihood of experiencing a SAE than vancomycin and daptomycin, and a significantly lower risk of all-cause mortality than vancomycin, linezolid and tigecycline.

CONCLUSION

Dalbavancin affords a promising, new alternative IV antimicrobial agent which is as effective as traditional therapies, but with the added benefit of enabling clinicians to treat patients with ABSSSI in different organisational settings. Notwithstanding, any introduction of an effective treatment with a differential mode of administration into healthcare systems must be followed by a change in clinical practice and patient management in order to fully achieve desirable economic outcomes.

Efficacy of intravenous tigecycline in patients with Acinetobacter complex infections: results from 14 Phase III and Phase IV clinical trials

Background

Acinetobacter infections, especially multidrug-resistant (MDR) Acinetobacter infections, are a global health problem. This study aimed to describe clinical outcomes in patients with confirmed Acinetobacter spp. isolates who were treated with tigecycline in randomized clinical trials.

Materials and methods

Data from 14 multinational, randomized (open-label or double-blind), and active-controlled (except one) Phase III and IV studies were analyzed using descriptive statistics.

Results

A total of 174 microbiologically evaluable patients with Acinetobacter spp. infections (including MDR infections) were identified, and 95 received tigecycline to treat community-acquired pneumonia (CAP), diabetic foot infections (DFIs), hospital-acquired pneumonia (HAP), complicated intra-abdominal infections (cIAIs), infections with resistant pathogens (RPs), or complicated skin and skin-structure infections. The rate of cure of tigecycline for most indications was 70%–80%, with the highest (88.2%) in cIAIs. The rate of cure of the comparators was generally higher than tigecycline, but within each indication the 95% CIs for clinical cure for each treatment group overlapped. For most Acinetobacter isolates, the minimum inhibitory concentration of tigecycline was 0.12–2 μg/mL, with seven at 4 μg/mL and one at 8 μg/mL. The cure rate by tigecycline was 50% (95% CI 12.5%–87.5% in CAP) to 88.2% (95% CI 66.2%–97.1% in cIAIs) for all Acinetobacter, and 72.7% (95% CI 54.5%–93.2% in HAP) to 100% (95% CI 25%–100.0% in cIAIs) for MDR Acinetobacter. For the comparators, it was 83.8% (95% CI 62.8%–95.9% in HAP) to 100% (95% CI 75%–100% in cIAIs and 25%–100.0% in RPs) and 88% (95% CI 66%–97% in HAP) to 100% (95% CI 25%–100% in cIAIs and 75%–100% in DFIs), respectively.

Conclusion

These findings suggest that with appropriate monitoring, tigecycline may be a useful consideration for Acinetobacter infections alone or in combination with other anti-infective agents when other therapies are not suitable.

Risk factors and predictors of carbapenem-resistant Pseudomonas aeruginosa and Acinetobacter baumannii mortality in critically ill bacteraemic patients over a 6-year period (2010-15): antibiotics do matter

Purpose. Acinetobacter baumannii and Pseudomonas aeruginosa provoke serious infections, especially in intensive care unit (ICU) patients.Methodology. The risk factors and predictors of mortality for P. aeruginosa (n=84; 46 carbapenem-resistant) and A. baumannii (n=129; all carbapenem-resistant) bloodstream infections (BSIs) in an ICU were evaluated. Antibiotic susceptibility testing was performed using the agar disk diffusion method according to EUCAST guidelines. The minimum inhibitory concentration was determined by a gradient method (Etest). Multilocus sequence typing (MLST) was performed for P. aeruginosa during the carbapenem-resistant outbreak in 2014. Epidemiological data were collected from the patients' chart reviews.Results/Key findings. Hospitalization during the summer months, prior KPC-producing Klebsiella pneumoniae (KPC-Kp) BSI, and the administration of tigecycline, aminoglycosides and cortisone were independently associated with P. aeruginosa BSIs. MLST revealed the dissemination of clone ST227, including carbapenem-resistant P. aeruginosa strains. Hospitalization during the summer months, prior KPC-Kp BSI, and the administration of antibiotics, carbapenem and cortisone were independently associated with A. baumannii BSIs. The 30-day mortality rate for P. aeruginosa and A. baumannii BSI was 45.2 and 39.5 %, respectively. Sequential organ failure assessment (SOFA) score at onset, septic shock, age, and prior KPC-Kp BSI were significantly associated with P. aeruginosa BSI mortality. The administration of at least one active antibiotic was identified as a predictor of a good prognosis. Septic shock and simplified acute physiology score (SAPS) II at onset were independently associated with A. baumannii BSI mortality. The administration of at least one active antibiotic and colistin-vancomycin co-administration were identified as predictors of a good prognosis.Conclusion. KPC-Kp infection predisposes ICU patients to BSI by either A. baumannii or P. aeruginosa. The administration of at least one active antibiotic leads to better survival rates.

The efficacy and safety of tigecycline for the treatment of bloodstream infections: a systematic review and meta-analysis

Patients with bloodstream infections (BSI) are associated with high mortality rates. Due to tigecycline has shown excellent in vitro activity against most pathogens, tigecycline is selected as one of the candidate drugs for the treatment of multidrug-resistant organisms infections. The purpose of this study was to evaluate the effectiveness and safety of the use of tigecycline for the treatment of patients with BSI. The PubMed and Embase databases were systematically searched, to identify published studies, and we searched clinical trial registries to identify completed unpublished studies, the results of which were obtained through the manufacturer. The primary outcome was mortality, and the secondary outcomes were the rate of clinical cure and microbiological success. 24 controlled studies were included in this systematic review. All-cause mortality was lower with tigecycline than with control antibiotic agents, but the difference was not significant (OR 0.85, [95% confidence interval (CI) 0.31-2.33; P = 0.745]). Clinical cure was significantly higher with tigecycline groups (OR 1.76, [95% CI 1.26-2.45; P = 0.001]). Eradication efficiency did not differ between tigecycline and control regimens, but the sample size for these comparisons was small. Subgroup analyses showed good clinical cure result in bacteremia patients with CAP. Tigecycline monotherapy was associated with a OR of 2.73 (95% CI 1.53-4.87) for mortality compared with tigecycline combination therapy (6 studies; 250 patients), without heterogeneity. Five studies reporting on 398 patients with Klebsiella pneumoniae carbapenemase-producing K. pneumoniae BSI showed significantly lower mortality in the tigecycline arm than in the control arm. The combined treatment with tigecycline may be considered the optimal option for severely ill patients with BSI.

Proposal for shorter antibiotic therapies

OBJECTIVES

Reducing antibiotic consumption has now become a major public health priority. Reducing treatment duration is one of the means to achieve this objective. Guidelines on the therapeutic management of the most frequent infections recommend ranges of treatment duration in the ratio of one to two. The Recommendation Group of the French Infectious Diseases Society (SPILF) was asked to collect literature data to then recommend the shortest treatment durations possible for various infections.

METHODS

Analysis of the literature focused on guidelines published in French and English, supported by a systematic search on PubMed. Articles dating from one year before the guidelines publication to August 31, 2015 were searched on the website.

RESULTS

The shortest treatment durations based on the relevant clinical data were suggested for upper and lower respiratory tract infections, central venous catheter-related and uncomplicated primary bacteremia, infective endocarditis, bacterial meningitis, intra-abdominal, urinary tract, upper reproductive tract, bone and joint, skin and soft tissue infections, and febrile neutropenia. Details of analyzed articles were shown in tables.

CONCLUSION

This work stresses the need for new well-conducted studies evaluating treatment durations for some common infections. Following the above-mentioned work focusing on existing literature data, the Recommendation Group of the SPILF suggests specific study proposals.

New therapeutic options for skin and soft tissue infections

PURPOSE OF REVIEW

The occurrence of methicillin-resistance in Staphylococcus aureus, that represents the most frequent cause of complicated skin and soft tissue infections (cSSTIs) worldwide, is a major concern and has been associated with increased length of stay, health care costs, and overall mortality. Although vancomycin is still considered the standard therapy in this setting, limitations of its use in clinical practice are represented by a progressive increase in methicillin-resistant S. aureus (MRSA) minimum inhibitory concentrations, drug-related toxicity, and the lack of an oral formulation. New therapeutic options for MRSA cSSTIs have recently become available, with promising implications for the management of cSSTIs in clinical practice.

RECENT FINDINGS

A number of new antimicrobials with activity against MRSA have been recently approved for the treatment of cSSTIs, and other agents are under investigation. We have reviewed the recent developments, with a specific focus on the possible advantages of new drugs for the management of cSSTIs into the everyday clinical practice.

SUMMARY

The new approved drugs for the treatment of cSSTIs are expected to offer many advantages for the management of patients with suspected or confirmed MRSA cSSTIs. The most promising features of the new compounds include the availability of oral formulations, once-weekly intravenous regimens, and broad spectra of activity.

Clinician-reported lesion measurements in skin infection trials: Definitions, reliability, and association with patient-reported pain

OBJECTIVES

Outcome assessments as clinical trial endpoints should be well-defined, reliable, and reflect meaningful treatment benefits. For acute bacterial skin and skin structure infections (ABSSSI) trials, recent recommendations suggest a primary endpoint of reduction in skin lesion area. Objectives were: evaluate ABSSSI lesion area measurement reliability, evaluate impact of various lesion area definitions on treatment effect size, and explore relationships between lesion area and pain.

METHODS

Data from two randomized, double-blinded Phase 3 trials comparing tedizolid to linezolid in ABSSSI and one open-label, non-comparative Phase 2 study of tedizolid in cellulitis/erysipelas and skin abscess were analyzed. Repeated lesion area measurements were prospectively obtained in all studies. In the open-label study, lesion area was measured by two investigators, using four different definitions. Repeated pain assessments using two patient-reported outcome instruments (Visual Analog Scale [VAS] and Faces Rating Scale [FRS]) were elicited in the randomized trials.

RESULTS

At baseline, lesion size did not correlate with pain intensity: r=0.02 for VAS and r<0.01 for FRS pain scores. However, decreasing lesion size and decreasing pain were strongly associated over time, regardless of initial lesion size or pain intensity (r=0.20 for VAS and r=0.21 for FRS scores at Day 10-13). Each lesion area definition demonstrated high inter-observer reliability (intra-class correlation coefficient>0.95).

CONCLUSIONS

Decreasing lesion area (indirect clinician-reported measure of benefit) and pain (direct patient-reported measure of benefit) were strongly associated over time, and lesion area measurements were reliable, regardless of their definition. These findings support both measures as outcome assessments in ABSSSI clinical trials.

REGISTRATION

Clinicaltrials.govNCT01519778, NCT01170221, and NCT01421511.

Acute bacterial skin and skin structure infections in internal medicine wards: old and new drugs

Skin and soft tissue infections (SSTIs) are a common cause of hospital admission among elderly patients, and traditionally have been divided into complicated and uncomplicated SSTIs. In 2010, the FDA provided a new classification of these infections, and a new category of disease, named acute bacterial skin and skin structure infections (ABSSSIs), has been proposed as an independent clinical entity. ABSSSIs include three entities: cellulitis and erysipelas, wound infections, and major cutaneous abscesses This paper revises the epidemiology of SSTIs and ABSSSIs with regard to etiologies, diagnostic techniques, and clinical presentation in the hospital settings. Particular attention is owed to frail patients with multiple comorbidities and underlying significant disease states, hospitalized on internal medicine wards or residing in nursing homes, who appear to be at increased risk of infection due to multi-drug resistant pathogens and treatment failures. Management of ABSSSIs and SSTIs, including evaluation of the hemodynamic state, surgical intervention and treatment with appropriate antibiotic therapy are extensively discussed.

Efficacy and safety of tigecycline for the treatment of severe infectious diseases: an updated meta-analysis of RCTs

OBJECTIVES

To assess the efficacy and safety of tigecycline in comparison with other antimicrobial treatments for infectious diseases.

DESIGN

Databases of PubMed, Embase and the Cochrane Library were searched through Feb. 2015. The reference lists of the initially identified articles and systemic review articles were manually searched. Randomized controlled trials assessing tigecycline and other antibiotics for infectious diseases in adult patients were included.

RESULTS

Fifteen RCTs including 7689 cases were identified. We found that tigecycline was not as effective as the comparator agents for clinical treatment success (for the clinically evaluable population, odds ratio [OR] = 0.83, 95% confidence interval [CI] = (0.73, 0.96), P=0.01; for the clinically modified intent-to-treat (mITT) population, OR = 0.81, 95% CI = (0.72, 0.92), P=0.001). There was no significant difference in microbiological treatment success with lower eradication rate in tigecycline versus comparators (for the microbiologically evaluable population, OR = 0.94, 95% CI = (0.77, 1.16), P=0.56; for the microbiological mITT populations, OR = 0.91, 95% CI = (0.74, 1.11), P=0.35). Adverse events and all-cause mortality were more common in the tigecycline group.

CONCLUSIONS

Tigecycline is not as effective as other antibiotics with relatively more frequency of adverse events and higher mortality rate.

Pathogens of skin and skin-structure infections in the UK and their susceptibility to antibiotics, including ceftaroline

OBJECTIVES

Bacterial skin and skin-structure infections (SSSIs) are frequent settings for antibiotic use. We surveyed their UK aetiology and pathogen susceptibility, including susceptibility to ceftaroline.

METHODS

Consecutive SSSI isolates were collected at 35 UK hospitals, to a maximum of 60/site, together with 15 'supplementary' MRSA/site. Isolates were re-identified and BSAC susceptibility testing was performed, with parallel CLSI agar testing for ceftaroline.

RESULTS

Isolates (n = 1908) were collected from 1756 hospitalized patients, predominantly with surgical and traumatic infections, abscesses and infected ulcers and largely from general medicine and general surgery patients. They included 1271 Staphylococcus aureus (201 MRSA), 162 β-haemolytic streptococci, 269 Enterobacteriaceae, 138 Pseudomonas aeruginosa and 37 enterococci. Most (944/1756) patients had monomicrobial MSSA infections. Rates of resistance to quinolones, gentamicin and cephalosporins were <20% in Enterobacteriaceae and <10% in P. aeruginosa. MRSA rates varied greatly among hospitals and were 2.5-fold higher in general medicine than in general surgery patients. At breakpoint, ceftaroline inhibited: (i) all MSSA and 97.6% of MRSA, with MICs of 2 mg/L for the few resistant MRSA; (ii) all β-haemolytic streptococci; and (iii) 83% of Enterobacteriaceae. High-level ceftaroline resistance in Enterobacteriaceae involved ESBLs or AmpC enzymes. Ceftaroline MICs by CLSI methodology generally equalled those by BSAC or were 2-fold higher, but this differential was 4-16-fold for P. aeruginosa.

CONCLUSIONS

Irrespective of patient group, SSSIs were dominated by S. aureus. Most pathogens were susceptible, but 15.8% of S. aureus were MRSA, with locally higher prevalence.

Comparative efficacy of antibiotics for the treatment of acute bacterial skin and skin structure infections (ABSSSI): a systematic review and network meta-analysis

OBJECTIVE

The objective was to conduct a systematic review and network meta-analysis (NMA) of existing treatments for ABSSSI focusing on the novel lipoglycopeptide oritavancin.

METHODS

EMBASE, MEDLINE, MEDLINE in Process, CENTRAL (Cochrane), and select conferences were searched for randomized controlled trials investigating antimicrobial agents for the treatment of ABSSSI. NMA was used to estimate the odds ratios of the Test-Of-Cure (TOC) and Early Clinical Response (ECR) outcomes for treatments relative to vancomycin in the ITT populations. Sub-group analyses in MRSA and MSSA populations were conducted for TOC; sensitivity analyses investigated the use of the clinically evaluable (CE) populations and the restriction to trials following the recent FDA guidelines for clinical trials.

RESULTS

The systematic review identified 52 trials. The most commonly investigated treatments were vancomycin and linezolid; most trials reported TOC, but not ECR. The posterior mean and 95% credible intervals for odds ratios of TOC for antimicrobial agents relative to vancomycin were: linezolid (1.55; 0.91-2.57), daptomycin (2.18; 0.90-5.42), and oritavancin 1200 mg (1.06; 0.80-1.43). The odds ratio of ECR for oritavancin 1200 mg was 1.02 (0.23-4.33). In the MRSA sub-group the odds ratios relative to vancomycin for TOC were: linezolid (1.55; 0.96-2.46), daptomycin (0.74; 0.13-3.66), and oritavancin 1200 mg (0.94; 0.44-2.02). In the MSSA sub-group they were linezolid (1.36; 0.15-13.34) and oritavancin 1200 mg (0.82; 0.08-7.83). These results were robust to the sensitivity analyses.

CONCLUSIONS

This NMA provides a unified framework for the comparison of all available antimicrobial agents used in the treatment of ABSSSI and is the first to assess the ECR end-point. The results suggest equivalence of clinical efficacy between vancomycin, daptomycin, linezolid, and novel antimicrobial agents including oritavancin for the treatment of ABSSSI at TOC. The wide uncertainty margins indicate the heterogeneity of the available evidence and the need for further research.

[Efficacy observation of tigecycline in the treatment of 107 patients with infection due to granulocytopenia]

OBJECTIVE

To observe the curative effect and side effect of tigecycline in the treatment of patients with infection caused by granulocytopenia.

METHODS

The clinical data of 107 patients who were treated with tigecycline for infection due to granulocytopenia were retrospectively reviewed. The tigecycline was administered by intravenously (30-60 min drip infusion)as the initial dose of 100 mg and maintenance does of 50 mg, every 12h. The whole treatment course kept for 5-7 d when the body temperature was normal and then the step-down treatment or discontinuation of the drug was adopted.

RESULTS

A total of 104 strains of bacteria were isolated from 107 cases of hospitalized patient, including 60 multi-drug resistant strains (MDR) and 2 extensively-drug resistant strains (XDR). The total effective rate of tigecycline treatment was 62.6%, including 30 cases with tigecycline alone (63.3% of the effective rate), 21 cases with tigecycline as initial treatment followed by combination with other antibiotics (61.9% of the effective rate), and 56 cases with tigecycline in combination with other antibiotics from the beginning of the treatment (62.5% of the effective rate). There was no statistical significant difference between the 3 treatment groups (P=0.994). Among the 39 patients with MDR strains, 22 patients' temperature was controlled , 9 patients died, and 8 patients' temperature remained uncontrolled. The clinical effective rate of these patients was 56.4%. The median onset time of tigecycline treatment was 3 days. The adverse drug reactions of nausea (11.2% ) and vomiting (8.4% )were tolerable.

CONCLUSION

Tigecycline is effective in treatment of resistant bacteria infection in patients with granulocytopenia. The side effects of tigecycline were few, safe and generally well tolerated.

Staphylococcus aureus infections: epidemiology, pathophysiology, clinical manifestations, and management

Staphylococcus aureus is a major human pathogen that causes a wide range of clinical infections. It is a leading cause of bacteremia and infective endocarditis as well as osteoarticular, skin and soft tissue, pleuropulmonary, and device-related infections. This review comprehensively covers the epidemiology, pathophysiology, clinical manifestations, and management of each of these clinical entities. The past 2 decades have witnessed two clear shifts in the epidemiology of S. aureus infections: first, a growing number of health care-associated infections, particularly seen in infective endocarditis and prosthetic device infections, and second, an epidemic of community-associated skin and soft tissue infections driven by strains with certain virulence factors and resistance to β-lactam antibiotics. In reviewing the literature to support management strategies for these clinical manifestations, we also highlight the paucity of high-quality evidence for many key clinical questions.

Clinical response and mortality in tigecycline complicated intra-abdominal infection and complicated skin and soft-tissue infection trials

An imbalance in all-cause mortality was noted in tigecycline phase 3 and 4 comparative clinical trials across all studied indications. We investigated clinical failure and mortality in phase 3 and 4 complicated skin and soft-tissue infection (cSSTI) and complicated intra-abdominal infection (cIAI) tigecycline trials using descriptive analyses of a blinded adjudication of mortality and multivariate regression analyses. Attributable mortality analyses of cSSTI revealed death due to infection in 0.1% of each treatment group (P=1.000). In cIAI, there were no significant differences between tigecycline (1.2%) and comparator (0.7%) subjects who died due to infection (P=0.243). For cIAI clinical failure, treatment interaction with organ dysfunction was observed with no difference observed between clinical cure for tigecycline (85.4%) and comparator (76.7%) treatment groups (odds ratio=0.58, 95% confidence interval 0.28-1.19). Tigecycline-treated subjects had more adverse events of secondary pneumonias (2.1% vs. 1.2%) and more adverse events of secondary pneumonias with an outcome of death (0.5% vs. 0.1%). These analyses do not suggest that tigecycline is a factor either for failure (cSSTI and cIAI studies) or for death (cIAI studies).

Tigecycline use in critically ill patients: a multicentre prospective observational study in the intensive care setting

PURPOSE

This prospective observational study aimed at describing prescription patterns of tigecycline and patient outcomes in 26 French intensive care units (ICU).

METHODS

Data of consecutive cases of adult patients treated with tigecycline were collected from the initiation until 7 days after the end of treatment. Response to treatment was classified as success, failure or undetermined and analyses were presented according to severity (SOFA score <7 or ≥7). Survival was recorded at 28 days.

RESULTS

A total of 156 patients were included (64% male, age 60 ± 15 years). At inclusion, 53% had a SOFA score ≥7; 93% had received prior anti-infective agents. Tigecycline was given as first-line treatment in 47% of patients, mostly in combination (67%), for intra-abdominal (IAI 56%), skin and soft tissue (SSTI 19%) or other infections. A total of 76% of the treated infections were hospital-acquired. Bacteraemia was reported in 12% of patients. Median treatment duration was 9 days. Tigecycline was prematurely stopped in 42% patients. The global success rate was 60% at the end of treatment, and significantly higher with treatment duration more than 9 days (76 vs. 47%, P < 0.001). Success rate was 65% for patients alive at the end of treatment. Success rates tended to decrease with illness severity, immunosuppression, bacteraemia and obesity. Survival rate at day 28 was 85% in the whole cohort and significantly higher in the less severely ill patients (P < 0.001).

CONCLUSIONS

Tigecycline success rates appear comparable to those reported in clinical studies in ICU with severe infections. Tigecycline could be an alternative in ICU patients.

Clinical experience in 52 patients with tigecycline-containing regimens for salvage treatment of Mycobacterium abscessus and Mycobacterium chelonae infections

OBJECTIVES

We report the largest clinical experience using tigecycline-containing regimens for salvage treatment of patients with Mycobacterium abscessus and Mycobacterium chelonae.

PATIENTS AND METHODS

Data were collected from 52 patients on emergency/compassionate use (n = 38) or two open-label studies (n = 7 patients each). Based on information that was available, 46 (88.5%) of the subjects received antibiotic therapy prior to treatment with tigecycline. Treatment groups were evaluated based on length of tigecycline therapy (<1 and ≥1 month). ClinicalTrials.gov identifiers: Study 205, NCT00600600 and Study 310, NCT00205816.

RESULTS

The most commonly used concomitant antimicrobials were macrolides, amikacin and linezolid. Pulmonary disease was the most common presentation (36/52; 69.2%), and 58.3% of these patients had underlying cystic fibrosis. The majority were M. abscessus complex (n = 30) or M. chelonae/abscessus (n = 4). With therapy ≥1 month (mean, 255.0 ± 265.7 days), 10/15 patients (66.7%) with cystic fibrosis and 16/26 (61.5%) overall were considered improved. Skin/soft-tissue/bone infections were the most common extrapulmonary infections. With therapy ≥1 month (mean, 143 ± 123 days), 9/12 patients (75.0%) were considered improved. Nine of the 16 cases reported as failures regardless of site of infection occurred in patients who stopped treatment due to adverse events. There were eight deaths; none was related to tigecycline.

CONCLUSIONS

Tigecycline given for ≥1 month as part of a multidrug regimen resulted in improvement in >60% of patients with M. abscessus and M. chelonae infections, including those with underlying cystic fibrosis, despite failure of prior antibiotic therapy. Adverse events were reported in >90% of cases, the most common being nausea and vomiting.

Methicillin-resistant Staphylococcus aureus infection epidemiology and clinical response from tigecycline soft tissue infection trials

Given increasing resistance, therapeutic options to treat MRSA soft tissue infections should be evaluated. This pooled analysis evaluated data from subjects enrolled in 6 tigecycline clinical trials with documented MRSA complicated skin and skin structure infections or diabetic foot infections (DFIs). Baseline characteristics were compared between subjects with and without molecularly classified community-acquired (CA) MRSA, specifically staphylococcal cassette chromosome mec (SCCmec) IV. Clinical response was compared by CA-MRSA designation and treatment group. A total of 378 subjects with MRSA soft tissue infections were identified, including 79 with DFI. A total of 249 (65.9%) were molecularly classified as CA-MRSA. Clinical response rates for MRSA soft tissue infection were similar between tigecycline and vancomycin (treatment difference, 1.0%; 95% confidence interval: -9.3, 12.0) as well as by infection type, SCCmec, and Panton-Valentine leukocidin (PVL) status. Tigecycline demonstrated comparable efficacy for treatment of MRSA soft tissue infections regardless of infection type, SCCmec, or PVL status.

Efficacy of tigecycline for the treatment of complicated skin and soft-tissue infections in real-life clinical practice from five European observational studies

OBJECTIVES

Tigecycline is an approved treatment for complicated skin and soft-tissue infections (cSSTIs). The efficacy of tigecycline as monotherapy or in combination with other antibacterials in the treatment of cSSTI in routine practice is described.

PATIENTS AND METHODS

Individual patient-level data were pooled from five European observational studies (July 2006 to October 2011).

RESULTS

A total of 254 cSSTI patients who received tigecycline were included (mean age 63.2 ± 14.9 years). Of these, 34.4% were in intensive care units, 54.5% acquired their infection in hospital and 90.9% had at least one comorbidity. Infection most commonly affected the limbs (62.4%) and 43.8% of infections were classified as necrotizing. The mean Acute Physiology and Chronic Health Evaluation (APACHE) II and Sequential Organ Failure Assessment (SOFA) scores at the beginning of treatment were 15.0 ± 7.9 (n = 205) and 5.8 ± 3.9 (n = 32), respectively, indicating high disease severity. Staphylococcus aureus (52.7%), Escherichia coli (18.0%) and Enterococcus faecium (12.0%) were the most frequently isolated pathogens; 32.9% of infections were polymicrobial and 30.5% were due to resistant pathogens. Overall, 71.8% received tigecycline as monotherapy and 28.2% as combination therapy for a mean duration of 12 days. Clinical response rates at the end of treatment were 79.6% for all patients who received the standard dosage (183/230), 86.7% for patients who received tigecycline as monotherapy (143/165), 75.0% for patients with a nosocomial infection (96/128), 75.3% for patients with an APACHE II score >15 (61/81) and 58.3% for patients with a SOFA score ≥ 7 (7/12).

CONCLUSIONS

In these real-life studies, tigecycline, alone and in combination, achieved favourable clinical response rates in patients with cSSTI with a high severity of illness.

Prescription behaviours for tigecycline in real-life clinical practice from five European observational studies

OBJECTIVES

There is limited information on the use of tigecycline in real-life clinical practice. This analysis aims to identify and understand tigecycline prescribing patterns and associated patient outcomes for approved indications.

PATIENTS AND METHODS

A pooled analysis of patient-level data collected on the prescription of tigecycline in five European observational studies (July 2006 to October 2011) was conducted.

RESULTS

A total of 1782 patients who received tigecycline were included in the analysis. Of these patients, 61.6% were male, the mean age was 63.4 ± 14.7 years, 56.4% were in intensive care units, 80.2% received previous antibiotic treatment and 91% had one or more comorbid conditions. The mean Acute Physiology and Chronic Health Evaluation (APACHE) II and Sequential Organ Failure Assessment (SOFA) scores at the beginning of treatment were 17.7 ± 7.9 and 7.0 ± 4.0, respectively. The majority of patients (58.3%) received tigecycline for treatment of complicated skin and soft-tissue infections (cSSTIs; n = 254) or complicated intra-abdominal infections (cIAIs; n = 785). Tigecycline was given at the standard dose (100 mg plus 50 mg twice daily) to 89.3% of patients for a mean duration of 11.1 ± 6.4 days. The main reasons for prescribing tigecycline were failure of previous therapy (46.1%), broad-spectrum antibiotic coverage (41.4%) and suspicion of a resistant pathogen (39.3%). Tigecycline was prescribed first-line in 36.3% of patients and as monotherapy in 50.4%. Clinical response rates to treatment with tigecycline alone or in combination were 79.6% (183/230; cSSTIs) and 77.4% (567/733; cIAIs).

CONCLUSIONS

Although tigecycline prescription behaviour showed some heterogeneity across the study sites, these results confirm a role for tigecycline in real-life clinical practice for the treatment of complicated infections, including those in critically ill patients, across Europe.

Resistance mechanisms and epidemiology of multiresistant pathogens in Europe and efficacy of tigecycline in observational studies

OBJECTIVES

Antimicrobial drug resistance is a growing problem in Europe and, even with differences in epidemiology, it is of great concern. The treatment of complicated skin and soft-tissue infections (cSSTIs) and complicated intra-abdominal infections (cIAIs) is hindered further by pathogens that are resistant to methicillin, carbapenems, third-generation cephalosporins and glycopeptides.

PATIENTS AND METHODS

An analysis of the microbiological results from five European observational studies (July 2006 to October 2011) evaluating the efficacy of tigecycline (prescribed as monotherapy or in combination with other antibacterials) for the treatment of cSSTI and cIAI is presented.

RESULTS

In total, 213 cSSTI and 623 cIAI patients were included; 34.4% and 56.6%, respectively, were critically ill in intensive care units. At baseline, at least one pathogen was isolated in 167 (78.4%) cSSTI and 464 (74.5%) cIAI patients, and 32.9% and 49.1% of infections were polymicrobial. In cSSTI, Staphylococcus aureus and Escherichia coli (52.7% and 18.0%, respectively) were the most frequently isolated pathogens, whereas in cIAI most infections were due to E. coli (41.8%), Enterococcus faecium (40.1%) and Enterococcus faecalis (21.1%). Clinical response was observed in >80% of patients with E. coli in both cIAI and cSSTI. In cSSTI patients, the clinical response rate to S. aureus was 80.8%. For cIAI, 77.4% of E. faecium and 79.5% of E. faecalis patients responded to treatment.

CONCLUSIONS

Tigecycline when given alone or in combination with other antibacterials appeared to be efficacious against multiple pathogens, affirming its role in real-life clinical practice as a broad-spectrum antibacterial for the treatment of patients with cSSTI and cIAI, including the critically ill, across Europe.

Pharmacokinetics, Pharmacodynamics, Safety and Tolerability of Tigecycline

The pharmacokinetics and pharmacodynamics of tigecycline have been extensively studied in laboratory models and healthy volunteers. Tigecycline is available as a parenteral agent, exhibits linear pharmacokinetics, has a long terminal half-life, is extensively distributed into the tissues and attains steady-state levels in serum by day 7. The pharmacokinetics of tigecycline appear unaffected by age, renal disease and food. Clinical trials have shown that tigecycline (50 mg i.v. q12h) in adults is safe and generally well tolerated for up to 11.5 days. Drug-related adverse events, which are typically mild to moderate in intensity and of limited duration, mainly include nausea and vomiting. Tolerability of tigecycline in fasting subjects is improved by the use of antiemetics. C. difficile-related complications with tigecycline are uncommon. In the majority of patients, tigecycline has minimal adverse effects on blood chemistry or haematology.

An alternate pathophysiologic paradigm of sepsis and septic shock: implications for optimizing antimicrobial therapy

The advent of modern antimicrobial therapy following the discovery of penicillin during the 1940s yielded remarkable improvements in case fatality rate of serious infections including septic shock. Since then, pathogens have continuously evolved under selective antimicrobial pressure resulting in a lack of significant improvement in clinical effectiveness in the antimicrobial therapy of septic shock despite ever more broad-spectrum and potent drugs. In addition, although substantial effort and money has been expended on the development novel non-antimicrobial therapies of sepsis in the past 30 years, clinical progress in this regard has been limited. This review explores the possibility that the current pathophysiologic paradigm of septic shock fails to appropriately consider the primacy of the microbial burden of infection as the primary driver of septic organ dysfunction. An alternate paradigm is offered that suggests that has substantial implications for optimizing antimicrobial therapy in septic shock. This model of disease progression suggests the key to significant improvement in the outcome of septic shock may lie, in great part, with improvements in delivery of existing antimicrobials and other anti-infectious strategies. Recognition of the role of delays in administration of antimicrobial therapy in the poor outcomes of septic shock is central to this effort. However, therapeutic strategies that improve the degree of antimicrobial cidality likely also have a crucial role.

Comparative analysis of empiric antimicrobial treatments for skin and soft tissue infections in newly hospitalized patients

PURPOSE

Intravenous vancomycin is the standard empiric treatment for complicated skin and soft tissue infections (SSTIs) due to its coverage against methicillin-resistant Staphylococcus aureus (MRSA). The objective of this study was to compare the hospital length of stay (LOS) between vancomycin-treated patients and patients receiving newer anti-MRSA agents. The study also aimed to identify factors associated with therapy change in patients receiving vancomycin on admission.

METHODS

Electronic medical records were used to conduct this retrospective cohort study. The LOS was compared among 5 groups of adult patients with admission diagnoses for SSTI who were initiated on linezolid, daptomycin, ceftaroline, tigecycline, or vancomycin. Survival analysis was used to identify factors associated with therapy change from vancomycin to another study medication.

RESULTS

Vancomycin was prescribed in 1046 (92%) admissions. Although none of the between-group differences in LOS reached statistical significance, there was a trend toward shorter LOS in vancomycin-treated patients compared to linezolid-treated patients (P = .059). Coagulopathy was independently associated with increased likelihood of therapy change from vancomycin (hazard ratio = 4.71; P <.001).

CONCLUSIONS

In the treatment of SSTI, newer agents result in LOS comparable to vancomycin. In patients initiated on vancomycin, therapy change was associated with longer LOS. Coagulopathy was independently associated with increased probability of therapy change.

Tigecycline does not prolong corrected QT intervals in healthy subjects

We evaluated the effect of tigecycline (50-mg and 200-mg doses) on corrected QT (QTc) intervals and assessed safety and tolerability in a randomized, placebo-controlled, four-period crossover study of 48 (44 male) healthy volunteers aged 22 to 53 years. Fed subjects received tigecycline (50 mg or 200 mg) or placebo in a blinded fashion or an open-label oral dose of moxifloxacin (400 mg) after 1 liter of intravenous fluid. Serial electrocardiograms were recorded before, and for 96 h after, dosing. Blood samples for tigecycline pharmacokinetics were collected after each recording. QTc intervals were corrected using Fridericia's correction (QTcF). Pharmacokinetic parameters were calculated using noncompartmental methods with potential relationships examined using linear mixed-effects modeling. Adverse events were recorded. The upper limits of the 90% confidence interval for the mean difference between both tigecycline doses and placebo for all time-matched QTcF interval changes from baseline were <5 ms. The tigecycline concentrations initially declined rapidly and then more slowly. In the group given 50 mg of tigecycline, the pharmacokinetic parameters and means were as follows: maximum concentration of drug in serum (C(max)), 432 ng/ml; area under the concentration-time curve from time zero extrapolated to infinity (AUC0-∞), 2,366 ng · h/ml; clearance (CL), 21.1 liters/h; volume of distribution at steady state (V(ss)), 610 liters; and terminal half-life (t(1/2)), 22.1 h. Proportional or similar values were found for the group given 200 mg of tigecycline. Linear mixed-effects modeling failed to show an effect on QTcF values by tigecycline concentrations (P = 0.755). Tigecycline does not prolong the QTc interval in healthy subjects. This study has been registered at ClinicalTrials.gov under registration no. NCT01287793.

Retrospective evaluation of colistin versus tigecycline for the treatment of Acinetobacter baumannii and/or carbapenem-resistant Enterobacteriaceae infections

BACKGROUND

Therapeutic options are limited for infections because of Acinetobacter baumannii and carbapenem-resistant Enterobacteriaceae (CRE). Study aim was to compare the efficacy of colistin to tigecycline for the treatment of these types of infections.

METHODS

A retrospective study was conducted at the Detroit Medical Center. Adult patients with infections because of A baumannii or CRE in 2009 who received ≥2 doses of colistin or tigecycline were studied. Risk factors, outcomes, and costs were analyzed.

RESULTS

There were 82 patients with infections because of A baumannii, 12 with CRE, and 12 with A baumannii and CRE coinfection. Seventy-one patients received colistin, 16 received tigecycline, and 19 received both colistin and tigecycline. Seven isolates were nonsusceptible to colistin and 79 to tigecycline. Patients receiving colistin alone or in combination were more likely to die during their hospitalization than patients receiving only tigecycline (P = .002). However, patients receiving colistin had higher severity of acute illness and had notable delays in initiation of effective antimicrobial therapy (P < .001).

CONCLUSION

Compared with patients who received tigecycline alone, patients who received colistin alone or in combination had a higher severity of acute illness indices and delays in initiation of effective therapy. This increased severity of illness contributed to the increased rate of mortality among patients treated with colistin for A baumannii or CRE infections.

A randomized trial of tigecycline versus ampicillin-sulbactam or amoxicillin-clavulanate for the treatment of complicated skin and skin structure infections

BACKGROUND

Complicated skin and skin structure infections (cSSSIs) frequently result in hospitalization with significant morbidity and mortality.

METHODS

In this phase 3b/4 parallel, randomized, open-label, comparative study, 531 subjects with cSSSI received tigecycline (100 mg initial dose, then 50 mg intravenously every 12 hrs) or ampicillin-sulbactam 1.5-3 g IV every 6 hrs or amoxicillin-clavulanate 1.2 g IV every 6-8 hrs. Vancomycin could be added at the discretion of the investigator to the comparator arm if methicillin-resistant Staphylococcus aureus (MRSA) was confirmed or suspected within 72 hrs of enrollment. The primary endpoint was clinical response in the clinically evaluable (CE) population at the test-of-cure (TOC) visit. Microbiologic response and safety were also assessed. The modified intent-to-treat (mITT) population comprised 531 subjects (tigecycline, n = 268; comparator, n = 263) and 405 were clinically evaluable (tigecycline, n = 209; comparator, n = 196).

RESULTS

In the CE population, 162/209 (77.5%) tigecycline-treated subjects and 152/196 (77.6%) comparator-treated subjects were clinically cured (difference 0.0; 95% confidence interval [CI]: -8.7, 8.6). The eradication rates at the subject level for the microbiologically evaluable (ME) population were 79.2% in the tigecycline treatment group and 76.8% in the comparator treatment group (difference 2.4; 95% CI: -9.6, 14.4) at the TOC assessment. Nausea, vomiting, and diarrhea rates were higher in the tigecycline group.

CONCLUSIONS

Tigecycline was generally safe and effective in the treatment of cSSSIs.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00368537.