Early appropriate parenteral antimicrobial treatment of complicated skin and soft tissue infections caused by methicillin-resistant Staphylococcus aureus

Risk Factors And Clinical Outcomes Of Hospital-Acquired MRSA Infections In Chongqing, China

Background

Methicillin-resistant Staphylococcus aureus (MRSA) is a common pathogen of hospital infection with multi-drug resistant characteristics. Its spread and epidemic pose great challenges to nosocomial infection control. This study was aimed to identify risk factors for hospital-acquired MRSA (HA-MRSA) infections and investigate its clinical outcome, developing infection control strategies and improving patient outcomes.

Methods

A retrospective case-case-control study was conducted to compare patients in Southwest Hospital, Chongqing, People's Republic of China from January 2018 to December 2018 with control patients. In this study, 251 patients with MRSA nosocomial infection, 339 patients with methicillin-sensitive Staphylococcus aureus strains (MSSA) nosocomial infection, and 300 patients with non-Staphylococcus aureus infection were included.

Results

Multivariate analysis showed that presence of central venous catheters (odds ratio [OR], 1.932; 95% confidence interval [CI], 1.074–3.477; P=0.028), sputum suction (OR, 2.887; 95% CI, 1.591–5.240; p<0.001), and total hospital stays more than 30 days (OR, 3.067; 95% CI, 2.063–4.559; P<0.001) were independent risk factors for HA-MRSA. Renal insufficiency (OR, 2.744; 95% CI, 1.089–6.914; P=0.032) and receipt of immunosuppressors (OR, 3.140; 95% CI, 1.284–7.678; P=0.012) were independent predictors of poor prognosis of MRSA nosocomial infection. Moreover, empirical use of antibiotics (OR, 0.514; 95% CI, 0.282–0.935; P=0.029) was a protective factor for poor prognosis of MRSA nosocomial infection. In-hospital mortality in the MRSA group was not statistically significant compared with the other two groups; however, the rate of poor prognosis in the MRSA group was higher than that of the MSSA group (27.5% vs 17.1%, χ²=9.200, P=0.002) and the control group (27.5% vs 16.0%, χ²=19.190, P=0.001).

Conclusion

Our results have shown presence of central venous catheters, sputum suction, and total hospital stays more than 30 days were associated with nosocomial MRSA infection. Patients with renal insufficiency and immunosuppressive therapy were more likely to cause poor prognosis with MRSA infection, and the empirical use of antibiotics can effectively reduce the adverse clinical outcomes caused by MRSA infection. Based on above findings, strategies to control MRSA infection should emphasize more attention to these patients and appropriate empirical use of antibiotics.

Antibiotic Susceptibility and Treatment Response in Bacterial Skin Infection

Background

Bacterial skin infections occur secondarily in conditions involving a vulnerable skin barrier such as atopic eczema, as well as primarily such as impetigo. They are mainly caused by Staphylococcus aureus and Streptococci. Recently, the prevalence of methicillin-resistant S. aureus has been increasing.

Objective

To determine the characteristics of community-acquired bacterial skin infections, to observe their antibiotic susceptibility patterns, and to evaluate factors contributing to the treatment response.

Methods

We retrospectively reviewed outpatients under 30 years old from 2010 to 2015, from whom we had taken skin swabs for antibiotic susceptibility testing. We collected clinical and microbiological characteristics from the medical records.

Results

We evaluated the culture results of 197 patients and reviewed their medical records. Overall, 86.3% (n=170) of the patients responded to the initial treatment regimen. S. aureus was the most commonly isolated pathogen (52.6%) and showed a high resistance rate to penicillin (90.9%) and oxacillin (36.3%). In the multivariable logistic regression analysis, resistance to 3 or more antibiotics (p=0.044), culture amounts described as “many” (p=0.040), and non-systemic antibiotic use (p<0.001) were significantly associated with lower treatment response. However, methicillin resistance was not associated with lower treatment response both in univariable and multivariable analyses.

Conclusion

Among young patients, S. aureus was the most predominant pathogen present in bacterial skin infections. Resistance to high numbers of antibiotics and the use of non-systemic antibiotics were associated with lower treatment response. First-generation cephalosporins may be the most effective first-line empirical regimen for bacterial skin infections treated in outpatient settings, regardless of methicillin resistance.

Current and future trends in antibiotic therapy of acute bacterial skin and skin-structure infections

In 2013 the US Food and Drug Administration (FDA) issued recommendations and guidance on developing drugs for treatment of skin infection using a new definition of acute bacterial skin and skin-structure infection (ABSSSI). The new classification includes cellulitis, erysipelas, major skin abscesses and wound infection with a considerable extension of skin involvement, clearly referring to a severe subset of skin infections. The main goal of the FDA was to better identify specific infections where the advantages of a new antibiotic could be precisely estimated through quantifiable parameters, such as improvement of the lesion size and of systemic signs of infection. Before the spread and diffusion of methicillin-resistant Staphylococcus aureus (MRSA) in skin infections, antibiotic therapy was relatively straightforward. Using an empiric approach, a β-lactam was the preferred therapy and cultures from patients were rarely obtained. With the emergence of MRSA in the community setting, initial ABSSSI management has been changed and readdressed. Dalbavancin, oritavancin and tedizolid are new drugs, approved or in development for ABSSSI treatment, that also proved to be efficient against MRSA. Dalbavancin and oritavancin have a long half-life and can be dosed less frequently. This in turn makes it possible to treat patients with ABSSSI in an outpatient setting, avoiding hospitalization or potentially allowing earlier discharge, without compromising efficacy. In conclusion, characteristics of long-acting antibiotics could represent an opportunity for the management of ABSSSI and could profoundly modify the management of these infections by reducing or in some cases eliminating both costs and risks of hospitalization.

Pan-European early switch/early discharge opportunities exist for hospitalized patients with methicillin-resistant Staphylococcus aureus complicated skin and soft tissue infections

The objective of this study was to document pan-European real-world treatment patterns and healthcare resource use and estimate opportunities for early switch (ES) from intravenous (IV) to oral antibiotics and early discharge (ED) in hospitalized patients with methicillin-resistant Staphylococcus aureus (MRSA) complicated skin and soft tissue infections (cSSTIs). This retrospective observational medical chart review study enrolled 342 physicians across 12 European countries who collected data from 1542 patients with documented MRSA cSSTI who were hospitalized (July 2010 to June 2011) and discharged alive (by July 2011). Data included clinical characteristics and outcomes, hospital length of stay (LOS), MRSA-targeted IV and oral antibiotic use, and ES and ED eligibility according to literature-based and expert-validated criteria. The most frequent initial MRSA-active antibiotics were vancomycin (50.2%), linezolid (15.1%), clindamycin (10.8%), and teicoplanin (10.4%). Patients discharged with MRSA-active antibiotics (n = 480) were most frequently prescribed linezolid (42.1%) and clindamycin (19.8%). IV treatment duration (9.3 ± 6.5 vs. 14.6 ± 9.9 days; p <0.001) and hospital LOS (19.1 ± 12.9 vs. 21.0 ± 18.2 days; p 0.162) tended to be shorter for patients switched from IV to oral treatment than for patients who received IV treatment only. Of the patients, 33.6% met ES criteria and could have discontinued IV treatment 6.0 ± 5.5 days earlier, and 37.9% met ED criteria and could have been discharged 6.2 ± 8.2 days earlier. More than one-third of European patients hospitalized for MRSA cSSTI could be eligible for ES and ED, resulting in substantial reductions in IV days and bed-days, with potential savings of €2000 per ED-eligible patient.

Clinical outcomes of tigecycline alone or in combination with other antimicrobial agents for the treatment of patients with healthcare-associated multidrug-resistant Acinetobacter baumannii infections

Tigecycline (TG) has been shown to be active in vitro against Acinetobacter baumannii, although data on the clinical efficacy of TG alone or in combination for the treatment of infections due to multidrug-resistant A. baumannii (MDRAB) remain limited. The purpose of this study was to investigate the clinical outcomes of patients with healthcare-associated infections (HAIs) caused by MDRAB who were treated with imipenem/cilastatin and sulbactam, and TG alone or in combination with other antibiotics. A total of 386 patients with HAIs caused by MDRAB were retrospectively analyzed and grouped into TG and non-TG groups, depending on whether they received TG treatment. Of the 266 patients in the TG group, 108 were treated with TG alone and 158 were treated with TG in combination with ceftazidime, ceftriaxone, piperacillin/tazobactam, or a carbapenem. All 120 patients in the non-TG group were treated with imipenem/cilastatin and sulbactam. The primary outcome measure was 30-day mortality after TG treatment and the secondary outcome was clinical outcome. There were no significant differences in survival rates between the two groups. However, the rate of unfavorable outcome was significantly lower (p < 0.05) among patients in the TG group than among patients in the non-TG group. The most significant predictor of unfavorable outcome was sepsis, whereas TG treatment and microbial eradication were the most significant predictors of favorable outcomes. Our study represents the largest study of patients with MDRAB infection treated with TG and expands our understanding of the role of TG therapy alone or in combination with other agents for the treatment of HAI caused by MDRAB.

Common complications in the critically ill patient

Critically ill patients in intensive care units are subject to many complications associated with therapy. Many of these complications are health care-associated infections and are related to indwelling devices, including ventilator-associated pneumonia, central line-associated bloodstream infection, catheter-associated urinary tract infection; surgical site infection, venous thromboembolism, deep venous thrombosis, and pulmonary embolus are other common complications. All efforts should be undertaken to prevent these complications in surgical critical care, and national efforts are under way for each of these complications. In this article, epidemiology, risk factors, diagnosis, treatment, and prevention of these complications in critically ill patients are discussed.

Ceftaroline in complicated skin and skin-structure infections

Ceftaroline is an advanced-generation cephalosporin antibiotic recently approved by the US Food and Drug Administration for the treatment of complicated skin and skin-structure infections (cSSSIs). This intravenous broad-spectrum antibiotic exerts potent bactericidal activity by inhibiting bacterial cell wall synthesis. A high affinity for the penicillin-binding protein 2a (PBP2a) of methicillin-resistant Staphylococcus aureus (MRSA) makes the drug especially beneficial to patients with MRSA cSSSIs. Ceftaroline has proved in multiple well-conducted clinical trials to have an excellent safety and efficacy profile. In adjusted doses it is also recommended for patients with renal or hepatic impairment. Furthermore, the clinical effectiveness and high cure rate demonstrated by ceftaroline in cSSSIs, including those caused by MRSA and other multidrug-resistant strains, warrants its consideration as a first-line treatment option for cSSSIs. This article reviews ceftaroline and its pharmacology, efficacy, and safety data to further elucidate its role in the treatment of cSSSIs.

Cutaneous community-acquired and hospital-acquired methicillin-resistant Staphylococcus aureus

The clinical presentation of methicillin-resistant Staphylococcus aureus (MRSA) infection ranges from asymptomatic colonization to cutaneous and invasive involvement. This review discusses the cutaneous presentations of community-acquired MRSA (CA-MRSA) and hospital-acquired MRSA (HA-MRSA) that one may encounter in the hospital or outpatient setting. Cutaneous CA-MRSA and HA-MRSA are often clinically indistinguishable, although they have different epidemiologic profiles and virulence factors. Bacterial culture is necessary for diagnosis and guides treatment, as infection with CA-MRSA and HA-MRSA require distinct clinical management. Guidelines for surgical interventions and antibiotic treatment of CA-MRSA and HA-MRSA will be discussed. Strategies for MRSA decolonization and prevention of further spread will also be reviewed.

Prospective, open-label investigation of the pharmacokinetics of daptomycin during cardiopulmonary bypass surgery

As methicillin-resistant Staphylococcus aureus (MRSA) becomes more prevalent, vancomycin is becoming increasingly used as a prophylaxis against surgical-site infections for cardiothoracic surgeries. However, vancomycin administration can be challenging, and the pharmacokinetics of alternative antibiotics in this setting are poorly understood. The primary objective of this investigation was to describe the pharmacokinetics of daptomycin in patients undergoing coronary artery bypass graft surgery. We enrolled 15 patients undergoing coronary artery bypass surgery requiring cardiopulmonary bypass. Each subject was administered a single open-label dose of daptomycin (8 mg/kg of body weight) for surgical prophylaxis. Fourteen daptomycin plasma samples were collected. Safety outcomes between subjects who received daptomycin and 15 control subjects who received the standard-of-care antibiotic were compared. The mean maximal concentration of daptomycin (C(max)) was 84.4 ± 27.1 μg/ml; the mean daptomycin concentration during the cardiopulmonary bypass procedure was 33.2 ± 11.4 μg/ml and was 30.9 ± 12.7 μg/ml at sternum closure. Mean daptomycin concentrations at 12, 18, 24, and 48 h were 22.7 ± 9.7, 16.2 ± 8.2, 12.0 ± 4.7, and 3.5 ± 2.3 μg/ml, respectively. Mean daptomycin concentrations were consistently above the MIC at which 90% of the tested isolates are inhibited (MIC₉₀) for S. aureus and S. epidermidis during the cardiopulmonary bypass procedure. Daptomycin was not associated with surgical-site infections or differences in adverse events compared to findings for control subjects. We found that a single dose of daptomycin at 8 mg/kg was well tolerated and achieved adequate plasma concentrations against common pathogens associated with surgical-site infections after cardiothoracic surgery. Daptomycin may be considered an alternative surgical prophylaxis antibiotic for patients undergoing cardiothoracic bypass surgery who are unable to receive vancomycin.

Complicated skin and soft tissue infection

Skin and soft tissue infections (SSTIs) are common, and complicated SSTIs (cSSTIs) are the more extreme end of this clinical spectrum, encompassing a range of clinical presentations such as deep-seated infection, a requirement for surgical intervention, the presence of systemic signs of sepsis, the presence of complicating co-morbidities, accompanying neutropenia, accompanying ischaemia, tissue necrosis, burns and bites. Staphylococcus aureus is the commonest cause of SSTI across all continents, although its epidemiology in terms of causative strains and antibiotic susceptibility can no longer be predicted with accuracy. The epidemiology of community-acquired and healthcare-acquired strains is constantly shifting and this presents challenges in the choice of empirical antibiotic therapy. Toxin production, particularly with Panton-Valentine leucocidin, may complicate the presentation still further. Polymicrobial infection with Gram-positive and Gram-negative organisms and anaerobes may occur in infections approximating the rectum or genital tract and in diabetic foot infections and burns. Successful management of cSSTI involves prompt recognition, timely surgical debridement or drainage, resuscitation if required and appropriate antibiotic therapy. The mainstays of treatment are the penicillins, cephalosporins, clindamycin and co-trimoxazole. β-Lactam/β-lactamase inhibitor combinations are indicated for polymicrobial infection. A range of new agents for the treatment of methicillin-resistant S. aureus infections have compared favourably with the glycopeptides and some have distinct pharmacokinetic advantages. These include linezolid, daptomycin and tigecycline. The latter and fluoroquinolones with enhanced anti-Gram-positive activity such as moxifloxacin are better suited for polymicrobial infection.

Emerging drugs for complicated skin and skin-structure infections

IMPORTANCE OF THE FILED: With the worldwide surge of MRSA, skin and skin-structure infection (SSTI) treatment has become a challenge for physicians. Cultures and antibiotic susceptibility tests for SSTIs are the rule due to the implication in morbidity and mortality rates associated with MRSA infections. The need for new antibiotics is evident and the effort to decrease antibiotic resistance is a world priority.

AREAS COVERED IN THIS REVIEW

This manuscript accesses the actual treatments and the developing of antibiotics for MRSA SSTIs.

WHAT THE READER WILL GAIN

This is a review of the data on the available and emerging treatments for MRSA SSTIs.

TAKE HOME MESSAGE

There is an unmet medical need for new antibiotics in the new millennium. As physicians, we must assure all appropriate procedures are completed in order to reduce the bacterial resistance, especially for MRSA.

Novel approach to antibiotic prophylaxis in percutaneous endoscopic gastrostomy (PEG): randomised controlled trial

OBJECTIVE

To evaluate a new and simpler strategy of antibiotic prophylaxis in percutaneous endoscopic gastrostomy (PEG).

DESIGN

Single centre, two arm, randomised, controlled, double blind clinical trial.

SETTING

Endoscopy unit in Karolinska University Hospital, Stockholm, Sweden, between 3 June 2005 and 31 October 2009.

PARTICIPANTS

234 patients with an indication for PEG who gave informed consent to participate.

INTERVENTION

A single 20 ml dose of the oral solution of sulfamethoxazole and trimethoprim (also known as co-trimoxazole or Bactrim; F Hoffmann-La Roche Ltd, Basel, Switzerland) deposited in the PEG catheter immediately after insertion. The control group received standard prophylaxis consisting of a single intravenous dose of 1.5 g cefuroxime (Zinacef; GlaxoSmithKline, London) administered before insertion of the PEG tube.

MAIN OUTCOME MEASURE

Primary outcome was the occurrence of clinically evident wound infection within 14 days after insertion of the PEG catheter. Secondary outcomes were positive bacterial culture and blood tests (highly sensitive C reactive protein and white blood cell count). All randomised patients were included in an intention to treat analysis.

RESULTS

Of the 234 patients included in this study, 116 were randomly assigned to co-trimoxazole and 118 to cefuroxime. At follow-up 7-14 days after insertion of the PEG catheter, wound infection was found in 10 (8.6%) patients in the co-trimoxazole group and 14 (11.9%) in the cefuroxime group, which corresponds to a percentage point difference of -3.3% (95% confidence interval -10.9% to 4.5%). The per protocol analysis, which comprised 100 patients in each group, gave similar results-10% and 13% infection in the co-trimoxazole and cefuroxime groups, respectively (percentage point difference -3.0%, 95% CI -11.8% to 5.8%). Both these analyses indicate non-inferiority of co-trimoxazole compared with cefuroxime because the upper bounds of the confidence intervals are lower than the pre-determined non-inferiority margin of 15%. Analyses of the secondary outcomes supported this finding.

CONCLUSION

20 ml of co-trimoxazole solution deposited in a newly inserted PEG catheter is at least as effective as cefuroxime prophylaxis given intravenously before PEG at preventing wound infections in patients undergoing PEG. Trial registration Current Controlled Trials ISRCTN18677736.

Severe soft tissue infections

Severe skin and soft tissue infections (SSTIs) frequently require management in the ICU, in part related to associated septic shock or toxic shock syndrome or associated organ failure. Four fundamental management principles are key to a successful outcome in caring for patients who have severe SSTIs, including (1) early diagnosis and differentiation of necrotizing versus nonnecrotizing SSTI, (2) early initiation of appropriate empiric broad-spectrum antimicrobial therapy with consideration of risk factors for specific pathogens and mandatory coverage for methicillin-resistant Staphylococcus aureus (MRSA), (3) source control (ie, early aggressive surgical intervention for drainage of abscesses and debridement of necrotizing soft tissue infections), and (4) pathogen identification and appropriate de-escalation of antimicrobial therapy. MRSA has emerged as the most common identifiable cause of severe SSTIs; therefore, initiation of empiric anti-MRSA antimicrobials is warranted in all cases of severe SSTIs. In addition, appropriate critical care management-including fluid resuscitation, organ support and nutritional support-is a necessary component in treating severe SSTIs.

Skin and soft tissue infection: microbiology and epidemiology

Skin and soft tissue infections (SSTIs) are common and range in severity from minor, self-limiting, superficial infections to life-threatening diseases requiring all the resources of modern medicine. The classification of SSTIs can be based on the anatomical site, clinical severity or microbial cause, but some classifications divide SSTIs into complicated and uncomplicated infections. Community-acquired SSTIs are most commonly caused by staphylococci or streptococci, but almost any organism is capable of causing inflammation within soft tissue. Recent epidemiological trends have shown an increase not only in healthcare-associated meticillin-resistant Staphylococcus aureus (MRSA), but also in MRSA acquired in the community. Many of the latter strains produce exotoxins and are epidemiologically distinct from healthcare-acquired strains. Factors that may affect the microbial cause include underlying disease such as diabetes or immune dysfunction; hospital attendance, injecting drug use, travel, animal contact and environmental contamination.