Overview of resistant gram-positive pathogens in the surgical patient

Staphylococci and enterococci are the most common pathogens in surgical-site and bloodstream infections. The emergence of drug resistance among these gram-positive bacteria thus poses a substantial threat to patients with surgical infections. Resistance to methicillin/oxacillin is frequently observed in Staphylococcus aureus isolates and is often accompanied by multidrug resistance. Vancomycin is usually the treatment of choice for infections caused by methicillin-resistant S. aureus (MRSA), so the recent appearance of S. aureus isolated with intermediate sensitivity to vancomycin is cause for concern. Vancomycin resistance has already appeared in most species of enterococci. Infections caused by vancomycin-resistant enterococci (VRE) are associated with increased mortality compared to infections caused by vancomycin-sensitive isolates. Measures for preventing vancomycin resistance include reducing the use of vancomycin and other agents that appear to be associated with VRE, including third-generation cephalosporins and anti-anaerobic drugs. Third-generation cephalosporins have also been implicated in the increased prevalence of MRSA infections. Prudent use of existing antibiotics is an essential strategy for combating the rising tide of drug-resistant gram-positive pathogens.     

Clinical experience with linezolid in conjunction with wound coverage techniques for skin and soft-tissue infections and postoperative osteomyelitis

Gram-positive organisms are emerging as possibly the most important nosocomial pathogens during the past decade. Methicillin-resistant Staphylococcus aureus (MRSA) is a frequent cause of infection in the postoperative patient. Burn victims are at high risk for developing vancomycin-resistant Enterococcus (VRE) and other multidrug-resistant microbial infections as a result of the immunocompromising effects of burn injury, prolonged intensive care unit stays, and broad-spectrum antibiotic therapy. To prevent serious and dreaded complications such as skin graft breakdown, delayed wound healing, loss of a limb, and even death, these infections require a combination of extensive antibiotic therapy and plastic surgical intervention. The objectives of this study were to report clinical experience with linezolid in addition to wound care, debridement, and wound coverage techniques for the treatment of S. aureus (including MRSA) and VRE infections. Forty patients received linezolid for infections of wound coverage such as an infected graft or flap, or received linezolid in conjunction with wound coverage techniques for a S. aureus or VRE infection. The median patient age was 53 years (range, 14-85 years), 55% were female, 28% of patients received intravenous (i.v.) linezolid only, 45% received i.v. with a switch to the oral formulation, and 28% received the oral formulation only. The clinical success rate of linezolid with adjuvant wound coverage techniques was 90.0% for osteomyelitis and was 100% for skin and soft-tissue infections. For infections of wound coverage, the clinical success rate was 83.3%. In conclusion, linezolid was an effective antibiotic for the treatment of S. aureus (including MRSA) and VRE infections in conjunction with wound coverage techniques. In addition, linezolid offers the option of treating these infections with an oral agent that is 100% bioavailable.     

Emerging bacterial pathogens: a consensus of the scientific data and the risk for development of multiple organ dysfunction syndrome

Antibiotic resistance in the hospital setting is continuing to increase, particularly in intensive care units (ICUs) and other areas of the hospital such as oncology units, where the use of empiric broad-spectrum antibiotics is common. The problem of antibiotic resistance is also compounded in the immunocompromised patient. Multi-drug resistance is common among both Gram-positive and -negative bacteria, and becoming more prevalent among fungi (yeast). Two major antibiotic-resistant pathogens include extended-spectrum beta-lactamase producing Klebsiella pneumoniae (ESBL-KP) and vancomycin-resistant enterococci (VRE). When infections occur with ESBL-KP, a carbapenem antibiotic is usually the drug of choice. When infection occurs with VRE, specific therapy is bacteriostatic, and the clinician may have to rely on empirically selected antibiotics or combinations of antibiotics to achieve a positive outcome. Two newly-approved agents, linezolid and quinupristin/dalfopristin can be used to treat infections caused by resistant gram-positive cocci, but the latter is approved for use against VR-E. faecium. Risk factors for the development of ESBL-KP include the use of extended-spectrum cephalosporins such as ceftazidime. Risk factors for the development of VRE include inappropriate use of vancomycin, extended-spectrum cephalosporins, and antianaerobic drug therapy such as clindamycin. Several institutions have documented a reduction in one or both of these resistant pathogens following a decrease in the use of extended-spectrum cephalosporins combined with the increased use of extended-spectrum penicillins/beta-lactamase inhibitor combinations, such as piperacillin/tazobactam, for the empiric therapy of infections. For VRE, a reduction in the inappropriate use of vancomycin is also an important interventional strategy along with improved infection control practice.     

The use of linezolid in the treatment of vancomycin-resistant enterococcal septicaemia in two patients with burn injuries

Vancomycin-resistant enterococci (VRE) are multi-resistant micro-organisms that have emerged as important nosocomial pathogens during the last decade. Emergence of this organism has been blamed mainly on the increased and inappropriate use of antibiotics, in particular, the cephalosporins and the glycopeptide, vancomycin. Burns patients are highly vulnerable to acquiring VRE infections, being both debilitated and immunocompromised, and often receiving antibiotics that further diminish their intrinsic microbial flora.We report on two patients with large burn injuries who acquired vancomycin-resistant enterococcal septicaemia during their in-patient stay. Both patients were successfully treated using the antibiotic, linezolid.Linezolid is the first in a new class of antibiotics known as the oxazolidinones whose mode of action inhibits early bacterial protein synthesis. Linezolid has a spectrum of activity against Gram-positive micro-organisms including methicillin-resistant Staphylococcus aureus (MRSA) and VRE, and can provide a useful treatment alternative to the glycopeptides.     

1 245株金黄色葡萄球菌临床感染分布及耐药性变迁

目的探讨临床分离的金黄色葡萄球菌的感染分布及耐药性变迁,为临床经验性用药及院内感染控制提供数据支持。 方法回顾调查分析本院2012年1月至2015年12月于住院部及门诊送检标本分离到的金黄色葡萄球菌耐药数据,使用Microscan Walkaway 40 Plus对金黄色葡萄球菌进行鉴定及抗菌药物敏感性试验,采用WHONET 5.6版本软件进行统计分析。 结果共分离1 245株金黄色葡萄球菌,主要分离自患者痰液（565株,45.4%）、伤口分泌物（234株,18.8%）、脓液（136株,10.9%）和血液（89株,7.1%）;检出657株耐甲氧西林金黄色葡萄球菌（MRSA）,检出率为52.8%,其中,痰液中MRSA检出率最高（75.6%）。金黄色葡萄球菌主要来源于神经外科（197株,15.8%）、ICU（172株,13.8%）、创伤骨科（161株,12.9%）和呼吸内科（132株,10.6%）;神经外科以MRSA检出率最高（77.2%）。金黄色葡萄球菌对利福平、复方新诺明、达托霉素、利奈唑胺、万古霉素和奎奴普丁/达福普汀敏感性较好,对青霉素类敏感性最差。MRSA仅对达托霉素、利奈唑胺、万古霉素和奎奴普丁/达福普汀敏感性较好,甲氧西林敏感金黄色葡萄球菌（MSSA）对常用抗菌药物除青霉素类以外的抗菌药物耐药率较低;MRSA对常用抗菌药物耐药率显著高于MSSA。 结论临床MRSA检出率较高,且对常用抗菌药物耐药形势严峻,临床科室经验用药同时应配合加强院内感染控制,预防及减少MRSA感染的发生。     

Linezolid eradicates MRSA better than vancomycin from surgical-site infections

BACKGROUND: The purpose of this analysis was to compare the efficacy of linezolid versus vancomycin in patients with suspected or proven gram-positive methicillin-resistant Staphylococcus aureus (MRSA) surgical-site infections. METHODS: An open-label, randomized, comparator-controlled, multicenter, multinational study was conducted in hospitalized patients. Patients were randomized 1:1 to receive linezolid 600 mg (intravenous [IV] or oral) every 12 hours (n = 66) or vancomycin 1 g every 12 hours IV (n = 69) for 7 to 21 days. Patients were assessed at the test-of-cure (TOC) visit, 7 days after completing therapy. RESULTS: Clinical success at TOC was documented in similar proportions of patients treated with linezolid or vancomycin. Of those with MRSA isolated, significantly more patients who received linezolid compared with those who received vancomycin were microbiologically cured (87% vs 48%, respectively; 95% confidence interval 16.51 to 60.27; P = 0.0022). CONCLUSION: Intravenous or oral linezolid was well tolerated and superior to vancomycin in treating patients with MRSA-infected surgical-site infections.     

New approaches for empiric therapy in Gram-positive sepsis

Nosocomial bloodstream infections (BSIs) have become an important cause of morbidity and mortality, particularly in intensive care units (ICUs). Gram-positive organisms are the prevalent causes of antibiotic-resistant BSI, especially Staphylococcus aureus, coagulase-negative staphylococci and enterococci. In recent years, several reports have shown an increase in antimicrobial resistance among Gram-positive bacteria isolated from patients in ICUs. In this context, methicillin-resistant Staphylococcus aureus (MRSA) is a major problem. In the ICU more than 50% of S. aureus isolates in Europe are resistant to methicillin. Although vancomycin became the drug of choice for MRSA and is still widely used for this indication, many studies suggest that when vancomycin MIC values are at the high end of the susceptibility range, vancomycin is less effective against MRSA. High MRSA prevalence combined with the widespread use of vancomycin for empirical Gram-positive coverage may lead to changes in patient outcomes. Here we describe the microbiological, pharmacological and clinical characteristics of three new antibacterials helpful in severe infections in ICU patients: linezolid, tigecycline and daptomycin. These new drugs have some limitations, and the possibility developing resistance is real. Knowledge of both old and new antibacterials is necessary to utilize them most effectively.     

A consensus statement on empiric therapy for suspected gram-positive infections in surgical patients

BACKGROUND: Multidrug resistance among gram-positive pathogens in tertiary and other care centers is common. A systematic decision pathway to help select empiric antibiotic therapy for suspected gram-positive postsurgical infections is presented. DATA SOURCES: A Medline search with regard to empiric antibiotic therapy was performed and assessed by the 15-member expert panel. Two separate panel meetings were convened and followed by a writing, editorial, and review process. CONCLUSIONS: The main goal of empiric treatment in postsurgical patients with suspected gram-positive infections is to improve clinical status. Empiric therapy should be initiated at the earliest sign of infection in all critically ill patients. The choice of therapy should flow from beta-lactams to vancomycin to parenteral linezolid or quinupristin-dalfopristin. In patients likely to be discharged, oral linezolid is an option. Antibiotic resistance is an important issue, and in developing treatment algorithms for reduction of resistance, the utility of these new antibiotics may be extended and reduce morbidity and mortality.     

重症医学科耐甲氧西林金黄色葡萄球菌肺部感染老年患者的药物治疗

目的比较3种抗耐甲氧西林金黄色葡萄球菌(MRSA)药物治疗重症医学科(ICU)MRSA肺部感染老年患者的疗效及对细菌清除率和不良反应的影响。 方法选取2015年3月至2017年5月青岛市中心医院ICU收治的114例老年MRSA肺部感染者作为研究对象,根据患者治疗药物不同分为万古霉素组、替考拉宁组和利奈唑胺组,每组各38例患者。比较各组患者的疗效、细菌清除率、治疗前后血清C-反应蛋白(CRP)、降钙素原(PCT)、白细胞计数、中性粒细胞比值变化以及不良反应发生率。 结果利奈唑胺组患者治疗总有效率显著优于万古霉素组和替考拉宁组(χ²= 7.018、P = 0.008,χ²= 4.070、P = 0.044)。利奈唑胺组患者细菌清除率显著高于万古霉素组和替考拉宁组(χ²= 5.182、P = 0.023,χ²= 4.211、P = 0.040)。各组患者治疗后CRP、PCT、白细胞计数、中性粒细胞比值均显著低于治疗前,且利奈唑胺组患者治疗后CRP、PCT、白细胞计数、中性粒细胞比值低于万古霉素组和替考拉宁组(P均< 0.05)。各组患者治疗后均发生恶心、呕吐、肝功能异常、肾毒性、血肌酐水平异常、血小板下降、贫血不良反应,各组不良反应总发生率差异无统计学意义(χ²= 0.647、P = 0.723)。 结论ICU MRSA肺部感染老年患者治疗药物中,利奈唑胺临床疗效、细菌清除率均优于万古霉素和替考拉宁,且临床安全性相当,为治疗MRSA肺部感染较为理想的选择。     

Clinical and economic outcomes of oral linezolid versus intravenous vancomycin in the treatment of MRSA-complicated, lower-extremity skin and soft-tissue infections caused by methicillin-resistant Staphylococcus aureus

BACKGROUND: Resistant bacteria often complicate the management of skin and soft tissue infections of the lower extremities. This open-label study compared oral linezolid and intravenous vancomycin for management of complicated skin and soft-tissue infections caused by methicillin-resistant Staphylococcus aureus (MRSA). METHODS: Patients aged 18 years or older with proven MRSA-related complicated skin and soft-tissue infections requiring surgical intervention were randomized to receive oral linezolid (n=30) or intravenous vancomycin (n=30) for 7 to 21 days. Clinical and microbiological outcomes, duration of hospitalization and drug treatment, and outpatient charges were determined. RESULTS: Linezolid was associated with greater rates of clinical cure and improvement (P=.015), a 3-day shorter median length of stay (P=.003), and reduced outpatient charges (P<.001). Vancomycin therapy was associated with more treatment failures and subsequent lower-extremity amputations (P=.011). CONCLUSIONS: Clinical outcomes were significantly better with linezolid than with vancomycin. Additionally, linezolid was associated with reduced length of stay and outpatient charges.     

Methicillin-resistant Staphylococcus aureus infection in liver transplantation: a matched controlled study

The purpose of this study was to evaluate the clinical impact of methicillin-resistant Staphylococcus aureus (MRSA) infections on transplant recipients. METHODS: Liver and kidney recipients with MRSA infections were retrospectively identified and compared to an age, gender, UNOS status, organ transplanted, and transplant date matched (2:1) non-MRSA-infected recipient control group. All MRSA infections were initially treated with vancomycin, and four (33%) liver recipients were converted to linezolid therapy after failing to improve with vancomycin. RESULTS: The overall MRSA infection incidence was 1.4% (24/1770) with MRSA more common in liver (3.75%; 12/320) than kidney transplants (0.8%; 12/1450) (P < .001). The most common sites of MRSA infection were blood (42%), lung (38%), and abdomen (29%). The MRSA group had a greater percentage of prior antibiotic usage (79% vs 40%; P < .0015). The MRSA group experienced more posttransplant complications (52% vs 19%; P < .011)), and exhibited a trend toward greater length of stay in the intensive care unit (7.8 vs 4.6 days; P = .09), but not overall length of stay. Survival was similar in MRSA and non-MRSA groups (75% vs 88%; P = .17). No significant differences in mortality were noted between liver and kidney recipients infected with MRSA (P = .6). CONCLUSION: MRSA infection is associated with a higher incidence of posttransplant complications and antibiotic usage in both liver and kidney recipients compared to patients with MRSA infection.     

Vancomycin intermediate and resistant Staphylococcus aureus. What the nephrologist needs to know

Individuals undergoing hemodialysis may be at increased risk for emerging antimicrobial resistance from vancomycin-intermediate Staphylococcus aureus (VISA) and vancomycin-resistant S. aureus (VRSA). The laboratory detection of VISA and VRSA is challenging and requires the use of well-thought-out algorithms. Newly available antimicrobials such as quinipristin/dalfopristin, linezolid, and daptomycin, as well as older drugs such as trimethoprim-sulfamethoxazole appear to be active against recent strains of VISA and VRSA. Prevention of VISA and VRSA necessitates determining the appropriateness of vancomycin use in renal patients and giving priority to infection control precautions in both inpatient and outpatient settings. Because most VISA and all VRSA to date have arisen from endemic methicillin-resistant S. aureus (MRSA), and in the case of VRSA have acquired genes from vancomycin-resistant enterococci (VRE), the emergence of VISA and VRSA should provide renewed motivation for the containment of MRSA and VRE transmission in the hemodialysis population.     

Linezolid treatment of prosthetic hip infections due to methicillin-resistant Staphylococcus aureus (MRSA)

Prosthetic joint infection is an infrequent but serious complication of total joint arthroplasty. Complete removal of all foreign material is essential, however when prosthesis removal is not possible or is contraindicated, suppressive antibiotic therapy with retention of the functioning hip arthroplasty may be considered. Linezolid, the first approved oxazolidinone, appears to be a promising new agent for the treatment of serious gram-positive infections. We report two cases of prosthetic hip infections with methicillin-resistant Staphylococcus aureus (MRSA) that were successfully treated with long courses of linezolid. This observation suggests that linezolid is a promising drug for the treatment of prosthetic joint infections due to MRSA or other gram-positive bacteria, particularly when other therapeutic approaches are not feasible or a long-term antibiotic therapy is required. Received: 18 May 2001/Accepted: 30 May 2001     

Infection with antimicrobial-resistant microorganisms in dialysis patients

The prevalence of antimicrobial-resistant microorganisms in various health care settings, including outpatient dialysis facilities, has increased dramatically in the last decade. Antimicrobial use and patient-to-patient transmission of resistant strains are the two main factors that have contributed to this rapid increase. Methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative staphylococci are commonly isolated as a cause of hemodialysis (HD) catheter-related bacteremia and peritoneal dialysis (PD)-related catheter infection and peritonitis. The widespread use of vancomycin in dialysis patients is of concern because of an increase in the prevalence of vancomycin-resistant enterococci (VRE) in dialysis patients. Staphylococci with reduced sensitivity to vancomycin have also appeared in dialysis patients. A more recent problem is the appearance of S. aureus isolates with a high degree of resistance to the topical antimicrobial agent mupirocin. This has been seen in PD patients who have received prophylactic application of mupirocin at the peritoneal catheter exit site. Appropriate antimicrobial use will help protect the efficacy of currently used antibiotics, such as vancomycin. Published guidelines for use of vancomycin should be followed. New antimicrobials such as linezolid and quinupristin/dalfopristin have activity against VRE and MRSA, but resistance to these agents has already occurred. Preventing transmission of antimicrobial-resistant microorganisms in health care settings, including outpatient dialysis facilities, is important in limiting the spread of these resistant organisms.     

Diabetic foot infections: microbiological aspects, current and future antibiotic therapy focusing on methicillin-resistant Staphylococcus aureus

Diabetic patients are at increased risk of complicated skin, skin structure and bone infections including infections of diabetic foot ulcerations (DFU). Analyses of epidemiology and microbial pathogenicity show that staphylococci seem to be predestined to induce such infections. In addition, multidrug resistance particularly due to an increasing prevalence of methicillin-resistant Staphylococcus aureus (MRSA) seems to be the challenge for effective antibiotic therapy. With regard to infections with MRSA, classical agents like vancomycin, linezolid, fosfomycin or trimethroprim-sulphametoxazol might be agents of choice in DFU. New-generation drugs including broad-spectrum tetracyclines like tigecycline, first and second generation of cyclic lipopeptides, anti-MRSA β-lactams including ceftobiprole and anti-MRSA antibodies are developed or in progress and the hope for the future.     

Successful treatment of methicillin-resistant Staphylococcus aureus meningitis using linezolid without removal of intrathecal infusion pump. Case report

Infection of an intrathecal pump system is a rare but serious complication and usually leads to the removal of the pump. The authors report the first case of methicillin-resistant Staphylococcus aureus (MRSA) meningitis in a patient with such a pump successfully treated with linezolid without the need for removal of the intrathecal pump. A 77-year-old woman with cervical myelopathy underwent implantation of an intrathecal pump system for baclofen administration. Two weeks after the procedure she developed meningitis caused by MRSA as isolated in cerebrospinal fluid (CSF) cultures, blood samples, and serum obtained from the pump pouch. Clinically she presented with meningism, somnolence, and signs of sepsis. When a combined intravenous antibiotic treatment regimen of vancomycin and rifampicin resulted in no clinical improvement, that regimen was discontinued and linezolid was administered intravenously as monotherapy. Within 3 days clinical and laboratory findings showed significant improvement. After 1 week of linezolid treatment, blood and CSF cultures were sterile. Intravenous treatment was administered for a total of 3 weeks, after which the patient was treated with oral linezolid for 3 months. During 18 months of follow-up, no new clinical or laboratory signs of infection were observed. These results confirm previous reports of the efficacy of linezolid for the treatment of severe infections of the central nervous system caused by multidrug-resistant Gram-positive bacteria, especially postneurosurgical infections.     

山东某三甲医院儿童急性骨髓炎致病菌及耐药性分析

目的 总结山东大学附属儿童医院儿童急性骨髓炎脓液培养及药敏结果,为临床抗生素的使用提供参考。方法 收集我院2018年1月至2023年1月诊治的115例儿童急性骨髓炎的病例资料进行回顾性分析,其中男孩71例,女孩44例,年龄19天～15岁,对脓液培养结果及药敏结果进行总结分析。结果 115例患儿中,53例为甲氧西林敏感性金黄色葡萄球菌（methicillin-susceptible Staphylococcus aureus,MSSA）,33例为耐甲氧西林金黄色葡萄球菌（methicillin-resistant Staphylococcus aureus,MRSA）,2例为肺炎链球菌,1例为肠炎沙门菌,1例为流感嗜血杆菌,25例为阴性。53例MSSA中,51例对氨苄西林耐药,42例对克林霉素耐药,41例对红霉素耐药,仅1例对庆大霉素耐药,所有患儿均对青霉素耐药,均对阿莫西林、头孢西丁、苯唑西林、万古霉素和利奈唑胺敏感。33例MRSA中,27例对克林霉素耐药,27例对红霉素耐药,3例对庆大霉素耐药,所有患儿均对氨苄西林、阿莫西林、头孢西丁、苯唑西林和青霉素耐药,均对万古霉素和利奈唑胺敏感...     

Empiric antimicrobial therapy in critical illness: results of a surgical infection society survey

BACKGROUND: Antibiotics are prescribed commonly in the intensive care unit (ICU). Often, therapy is initiated empirically; practice patterns are not well characterized. We documented approaches to empiric antibiotic therapy among members of the Surgical Infection Society (SIS). METHODS: We sent a scenario-based questionnaire to all SIS members. The hypothetical cases addressed empiric broad-spectrum therapy for a patient with pyrexia and leukocytosis and the use of vancomycin for central venous catheter infection. RESULTS: The 113 respondents were primarily surgeons (96%) with a university-based practice (92%). Most attended in the ICU (72%), and they had practiced for 14 +/- 8 years. Whereas 63% of the respondents identified overuse of antibiotics as a problem in their ICU, only 19% said inadequate treatment of infection was a concern. For a febrile patient with negative cultures who was receiving antibiotics, estimates of the likelihood of infection increased across the three scenarios as the degree of organ failure increased (p < 0.0001; chi-square test). Deteriorating organ function was associated with a decision to broaden empiric therapy (58% vs. 33%; p < 0.0001) and to initiate anti-fungal therapy (27% vs. 9%; p < 0.0001) rather than to stop antibiotics and re-culture (15% vs. 51%; p < 0.0001). There was considerable variability in management strategy across the scenarios: Even in the face of organ dysfunction, 58% of physicians would add or change empiric therapy, whereas 30% would not. For each scenario, 23 to 25 antibiotic regimens were designated as optimal therapy. Only 45% of the respondents would initiate empiric vancomycin for suspected central line infection. Variability in approach was not explained by critical care practice, academic position, or country. CONCLUSIONS: Clinical deterioration is a strong determinant of a decision to initiate or broaden empiric antibiotic therapy during critical illness. The substantial variability in approach suggests a state of clinical equipoise that calls for more rigorous evaluation through a randomized controlled trial.     

Vascular graft infection by Staphylococcus aureus: efficacy of cefazolin, teicoplanin and vancomycin prophylaxis protocols in a rat model.

OBJECTIVES: Prophylactic efficiencies of cefazolin, teicoplanin and vancomycin in a dacron graft infection model caused by methicillin-susceptible (MSSA) or -resistant Staphylococcus aureus (MRSA) were investigated. DESIGN: Prospective, randomized, controlled animal study. MATERIALS AND METHODS: Infections were established subcutaneously in the back of rats by implantation of Dacron prostheses followed by topical inoculation onto grafts of MSSA or MRSA. Experimental groups were as follows: Uncontaminated group (control), MSSA- or MRSA-contaminated and untreated groups, MSSA- or MRSA-contaminated groups treated with cefazolin, teicoplanin or vancomycin by one of three regimens (one day, two days, or three days regimen). Grafts were removed 7 days after the implantation and evaluated by using sonication and quantitative blood agar culture. RESULTS: Contaminated groups demonstrated graft infections. Cefazolin, teicoplanin and vancomycin profoundly prevented the graft infections in MSSA- or MRSA-contaminated groups. For each antibiotic regimen, the most effective prevention was achieved by the drugs given as three days regimen. For MSSA and MRSA, the order of the effectiveness was as follows: teicoplanin>vancomycin>cefazolin. CONCLUSION: As a prophylactic agent, teicoplanin seems to be more effective than vancomycin and cefazolin against vascular graft infections caused by MSSA and MRSA in rats.     

Increasing incidence of methicillin-resistant Staphylococcus aureus skin and soft-tissue infections: reconsideration of empiric antimicrobial therapy

BACKGROUND: Community-acquired methicillin-resistant Staphylococcus aureus (MRSA) rates are at an all time high. MRSA rates as high as 60% have been reported in patients presenting with skin and soft-tissue infections (SSTIs). Our objectives were to (1) examine the incidence of MRSA over a 7-year period in surgical patients with SSTIs, (2) examine the choice of empiric antibiotic therapy, and (3) evaluate the vancomycin minimum inhibitory concentration (MIC) in MRSA isolates. METHODS: The medical records of all patients who underwent operative debridement of SSTIs from 2000 to 2006 were retrospectively reviewed. Demographic data such as age, race, and gender as well as co-morbid risk factors were collected. Preoperative American Society of Anesthesiologists (ASA) score, temperature, WBC, creatinine, HgbA1c, albumin, and empiric antimicrobial of choice were also included. Microbiology of all operative cultures was recorded. Available vancomycin MIC data were collected. All data are presented as mean +/- standard error of the mean. A chi-square test was used for statistical analysis. RESULTS: From 2000 to 2006, 288 patients with operative debridement for SSTIs were identified. The mean age was 54 +/- 11 years. Fifty-two percent of patients had diabetes mellitus, 55% were tobacco users, 34% alcohol users, and 23% had hepatitis C. The mean temperature at presentation was 99.2 degrees +/- 1.5 degrees F. The mean white blood cell count was 13.8 +/- .9. The mean HgbA1c was 8.6 +/- 2.5. The mean body mass index was 30.1 +/- 8. Sixty-seven percent of patients had an ASA > or = 3. There was a significant increase in MRSA SSTIs in 2006 (77%) compared with 2000 (34%, P < .001). Correspondingly, there was a significant increase in empiric administration of vancomycin in 2006 (93%) compared with 2000 (18%, P < .001). The examination of vancomycin MIC shows a shift for MRSA isolates over this time period (MIC < or = .5 microg/mL, 62%, MIC = 1 microg/mL, 7%, and MIC = 2 microg/mL, 31%). CONCLUSION: Our study shows a significant and ongoing increase in the incidence of MRSA in patients with SSTIs. Empiric coverage with an MRSA antimicrobial should be used as first-line therapy. However, given the observed increase in vancomycin MIC, alternative MRSA antimicrobials should be considered.