Management of complicated skin and soft tissue infections with a special focus on the role of newer antibiotics

Ceftobiprole Activity against Bacteria from Skin and Skin Structure Infections in the United States from 2016 through 2018

Ceftobiprole medocaril is an advanced-generation cephalosporin prodrug that has qualified infectious disease product status granted by the US FDA and is currently being evaluated in phase 3 clinical trials in patients with acute bacterial skin and skin structure infections (ABSSSIs) and in patients with Staphylococcus aureus bacteremia. In this study, the activity of ceftobiprole and comparators was evaluated against more than 7,300 clinical isolates collected in the United States from 2016 through 2018 from patients with skin and skin structure infections. The major species/pathogen groups were S. aureus (53%), Enterobacterales (23%), Pseudomonas aeruginosa (7%), beta-hemolytic streptococci (6%), Enterococcus spp. (4%), and coagulase-negative staphylococci (2%). Ceftobiprole was highly active against S. aureus (MIC_50/90, 0.5/1 mg/liter; 99.7% susceptible by EUCAST criteria; 42% methicillin-resistant S. aureus [MRSA]). Ceftobiprole also exhibited potent activity against other Gram-positive cocci. The overall susceptibility of Enterobacterales to ceftobiprole was 84.8% (>99.0% susceptible for isolate subsets that exhibited a non-extended-spectrum β-lactamase [ESBL] phenotype). A total of 74.4% of P. aeruginosa, 100% of beta-hemolytic streptococci and coagulase-negative staphylococci, and 99.6% of Enterococcus faecalis isolates were inhibited by ceftobiprole at ≤4 mg/liter. As expected, ceftobiprole was largely inactive against Enterobacterales that contained ESBL genes and Enterococcus faecium Overall, ceftobiprole was highly active against most clinical isolates from the major Gram-positive and Gram-negative skin and skin structure pathogen groups collected at U.S. medical centers participating in the SENTRY Antimicrobial Surveillance Program during 2016 to 2018. The broad-spectrum activity of ceftobiprole, including potent activity against MRSA, supports its further evaluation for a potential ABSSSI indication.

Efficacy and safety of ceftolozane/tazobactam as therapeutic option for complicated skin and soft tissue infections by MDR/XDR Pseudomonas aeruginosa in patients with impaired renal function: a case series from a single-center experience

INTRODUCTION

Pseudomonas aeruginosa (PA) is a known cause of skin and soft tissue infections (SSTIs). Therapeutic options against multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of PA are limited, especially in patients with impaired renal function. Ceftolozane/tazobactam (C/T) is a novel beta-lactam/beta-lactamase inhibitor with powerful anti-PA activity. Thanks to its characteristics, it appears to be the best available anti-pseudomonal drug in many clinical scenarios. A case series of four adult patients followed between January 2018 and May 2019 is reported. All subjects presented complicated SSTIs by MDR- or XDR-PA and were affected by chronic kidney disease.

RESULTS

C/T was used as a monotherapy in three cases and in combination regimen in the remaining case. In two cases, C/T was the first-line option, in the remaining ones was the salvage treatment. All patients were successfully treated without worsening of renal function and without any other adverse events.

CONCLUSIONS

C/T may represent a useful option against MDR- and XDR-PA strains responsible of complicated SSTIs in patients affected by impaired renal function.

Short tryptophan- and arginine-rich peptide shows efficacy against clinical methicillin-resistant Staphylococcus aureus strains isolated from skin and soft tissue infections

In recent years methicillin-resistant Staphylococcus aureus has posed a challenge in treating skin and soft tissue infections. Finding new antimicrobial agents has therefore become imperative. We evaluated the in vitro antimicrobial activity of a synthetic peptide, P6, against multidrug resistant clinical strains of Staphylococcus aureus isolated from skin and soft tissue infections. The P6 antimicrobial effect was evaluated in vitro by determining MIC/MBC, the ratio of live/dead cells and the effects induced at membrane level. The therapeutic efficiency was determined against human skin cells. P6 inhibited growth for all strains between 8 and 16 mg/L and killed all bacterial strains at 16 mg/L. The therapeutic potential was found to be 30 and 15 in the presence of BSA. We showed that P6 localizes at membrane level, where it acts slowly, by depolarizing it and affecting its integrity. P6 can be considered a good candidate for use as an antimicrobial agent in topical applications.

Skin and Soft Tissue Infections: A Case of Necrotizing Fasciitis

Necrotizing fasciitis is a rapidly progressing soft tissue infection associated with a high rate of mortality. Vibrio vulnificus, a gram-negative bacillus found in warm seawater, is a rare but serious cause of necrotizing fasciitis. Definitive treatment is often delayed because of the vague clinical manifestations associated with the early stages of the disease. Delays in diagnosis are directly associated with increased mortality. Because infection with V. vulnificus progresses more rapidly than other causes of necrotizing fasciitis, patients presenting with soft tissue symptoms and who have been in contact with raw seafood or seawater should be considered at high risk for V. vulnificus-associated necrotizing fasciitis. Health care providers in northern and inland areas must be aware of patients who have recently traveled to regions where V. vulnificus is more common, such as warm coastal regions. Early fasciotomy, debridement, and culture-directed antimicrobial therapy are essential to improve survival. The case presented in this report highlights the importance of early diagnosis of V. vulnificus-associated necrotizing fasciitis.

Turning a Collagenesis-Inducing Peptide Into a Potent Antibacterial and Antibiofilm Agent Against Multidrug-Resistant Gram-Negative Bacteria

Antimicrobial resistance is becoming one the most serious health threats worldwide, as it not only hampers effective treatment of infectious diseases using current antibiotics, but also increases the risks of medical procedures like surgery, transplantation, bone and dental implantation, chemotherapy, or chronic wound management. To date, there are no effective measures to tackle life-threatening nosocomial infections caused by multidrug resistant bacterial species, of which Gram-negative species within the so-called "ESKAPE" pathogens are the most worrisome. Many such bacteria are frequently isolated from severely infected skin lesions such as diabetic foot ulcers (DFU). In this connection, we are pursuing new peptide constructs encompassing antimicrobial and collagenesis-inducing motifs, to tackle skin and soft tissue infections by exerting a dual effect: antimicrobial protection and faster healing of the wound. This produced peptide 3.1-PP4 showed MIC values as low as 1.0 and 2.1 μM against Escherichia coli and Pseudomonas aeruginosa, respectively, and low toxicity to HFF-1 human fibroblasts. Remarkably, the peptide was also potent against multidrug-resistant isolates of Klebsiella pneumoniae, E. coli, and P. aeruginosa (MIC values between 0.5 and 4.1 μM), and hampered the formation of/disaggregated K. pneumoniae biofilms of resistant clinical isolates. Moreover, this notable hybrid peptide retained the collagenesis-inducing behavior of the reference cosmeceutical peptide C16-PP4 ("Matrixyl"). In conclusion, 3.1-PP4 is a highly promising lead toward development of a topical treatment for severely infected skin injuries.

Pharmacokinetics and tolerability of IDP-73152 mesylate after a single oral administration under fasted and fed conditions in healthy volunteers

Background and objective

IDP-73152 mesylate is a peptide deformylase inhibitor under investigation for the treatment of complicated skin and respiratory tract infections. The objective of this study was to investigate the pharmacokinetic (PK) profile and tolerability of IDP-73152 and the effect of food after a single oral administration.

Methods

A dose block-randomized, double-blind, placebo-controlled, dose-escalation study was conducted. A total of 56 healthy volunteers received IDP-73152 mesylate in a single oral dose of 40, 80, 160, 320, 640, or 1280 mg in the fasted and fed (640 mg only) states. Blood and urine samples for PK analysis were collected up to 48 h post dose.

Results

The area under the plasma concentration-time curve (AUC_0-t) of IDP-73152 increased in a dose-proportional manner in the range of 40-320 mg. The mean terminal half-life decreased from 10.7 to 6.2 hrs as the dose increased. The fraction excreted unchanged in the urine ranged from 0.05 to 0.12. In the 640-mg dose group, food delayed the median time to peak concentration (t _max) from 0.9 to 3.5 hrs. Furthermore, the maximum plasma concentration (C_max) were decreased by 36.2%; however, AUC_0-t was not generally affected. No serious adverse event or clinically significant findings were observed.

Conclusions

The systemic exposure of IDP-73152 proportionally increased as the dose increased up to 320 mg. The rate of absorption and extent of exposure were reduced by food intake. IDP-73152 was well tolerated without clinically significant adverse effects after a single oral administration.

Antibacterials in the pipeline and perspectives for the near future

Antimicrobial resistance is a global threat to the management of infections in our patients. Sound stewardship of antibacterial agents at our disposal must be accompanied by a concerted effort to develop new agents to bolster our armamentarium. This review will cover the latest antibiotics that have come through the pipeline and the role they can play in the management of infections that are increasingly difficult to treat due to resistance mechanisms.

Recent advances in Staphylococcus aureus infection: focus on vaccine development

Staphylococcus aureus normally colonizes the nasal cavity and pharynx. After breaching the normal habitat, the organism is able to cause a number of infections at any site of the body. The development of antibiotic resistance has created a global challenge for treating infections. Therefore, protection by vaccines may provide valuable measures. Currently, several vaccine candidates have been prepared which are either in preclinical phase or in early clinical phase, whereas several candidates have failed to show a protective efficacy in human subjects. Approaches have also been made in the development of monoclonal or polyclonal antibodies for passive immunization to protect from S. aureus infections. Therefore, in this review we have summarized the findings of recently published scientific literature to make a concise report.