Let us keep you informed via our e mail news update. Click here for more information. Check the latest news now at our headline page. Discuss MRSA using the comments link at foot of stories). Discover our MRSA Watch book of the month - Visit our bookstore. We have 2,800+ stories - see list below or categories in side columns.
Link: Research Conference
Experts in MRSA will meet at the University of Liverpool next week to discuss research that will facilitate development of new treatments for the potentially fatal bacterium. Specialist from more than 20 leading research laboratories across Great Britain and Ireland, who work to further understanding of the bacterium, Staphylococcus aureus, will present their findings at the conference. World renowned scientist, Professor Henri Verbrugh from Erasmus University in Rotterdam, will lead the conference in a discussion about how Staph aureus establishes itself in the nose. If scientists can understand how the bacterium survives they may find ways to prevent people from carrying it in the first place and spreading it to others.
Link: Shining a light
Dr Mark Wainwright, a senior LJMU lecturer in medicinal chemistry, who has been researching the therapy for nearly 20 years, explained: “After decades of wonder drugs, man’s supremacy over the microbe is over. Over-prescription and misuse of antibacterial drugs are to blame for this rise in resistance and we urgently need to change the way in which we employ such valuable drugs.” He continued: “Photodynamic therapy could be an effective alternative treatment. If antibiotics use a sniper’s approach to killing infections, dye therapy is like a hand grenade. Bacteria and viruses have no defence against the active oxygen it releases. The Darwinian argument of ‘survival of the fittest’ doesn’t apply because all of the bacterial cells are destroyed so they can’t develop resistance to the therapy. Its low human toxicity and the local/topical application of the drugs also mean that patients have fewer side effects.” Photodynamic therapy (PDT) is a relatively straightforward and cheap therapy. It works by the topical application of light sensitive compounds (related to dyes) onto the infected area and then shining light onto it. The light causes the dye to produce a highly reactive form of oxygen in situ, which if released close enough to a bacteria or virus, kills them, halting the infection. The therapy doesn’t even require expensive lasers as the right wavelength can be provided by ordinary light sources.
Link: Photodynamic therapy of microbial infections
Photodynamic therapy (PDT) is coming of age as an efficient alternative treatment for microbial infections, a problem which is presently aggravated by the increasingly widespread diffusion of antibiotic-resistant microbial strains. In particular, the use of red light-absorbing photosensitizers as photodynamic antimicrobial agents is characterized by various favorable features, including: (a) the broad spectrum of antimicrobial action of selected phenothiazines, porphyrins, and phthalocyanines, which promote the photosensitized inactivation of Gram( ) and Gram(-) bacteria, fungi, mycoplasma, and parasites by using one phototherapeutic protocol and mild irradiation conditions; (b) porphyrins/phthalocyanines display no appreciable toxicity in the dark at photochemically active doses; (c) microbial cell death is primarily a consequence of membrane photodamage through a typically multitarget process, which minimizes the risk of both the onset of mutagenic processes and the selection of photoresistant cells; (d) such photosensitizers act with essentially identical efficiency against both wild and antibiotic-resistant strains, whereas no selection of photoresistant microbial pathogens has been observed; (e) a combination between antibiotic-based and photodynamic therapy is possible. A typical example of phthalocyanine-sensitized photoinactivation of methicillin-resistant Staphylococcus aureus (MRSA) is provided. At present, antimicrobial PDT appears to be especially convenient for the treatment of localized infections, such as oral candidosis, periodontitis or chronic wounds.
Link: Journal of Medical Microbiology.
Parotid gland infection as a source of meticillin-resistant Staphylococcus aureus bacteraemia has been rarely reported. It is predominantly a disease of the elderly and is associated with significant mortality. Two cases are described here that presented over a 6 month history at a district general hospital. Many cases may be preventable with adequate hydration and good oral hygiene, combined with effective infection control.
Link: Journal of Antimicrobial Chemotherapy.
MRSA Watch will comment on these further in due course. They suggest that the decolonisation agents currenly in use are beggining to fail.
These evidence-based guidelines have been produced after a literature review of the treatment and prophylaxis of methicillin-resistant Staphylococcus aureus (MRSA) infection. The guidelines were further informed by antibiotic susceptibility data on MRSA from the UK. Recommendations are given for the treatment of common infections caused by MRSA, elimination of MRSA from carriage sites and prophylaxis of surgical site infection. There are several antibiotics currently available that are suitable for use in the management of this problem and potentially useful new agents are continuing to emerge.
Link: HighWire Press -- Medline Abstract.
We compared patients with MRSA VAP to persons with MSSA VAP. ICU length of stay represented the primary end point and ICU-free days served as a secondary end point. We recorded information regarding multiple confounders, including demographics, reasons for ICU admission and mechanical ventilation (MV), severity of illness at both ICU admission and time of diagnosis of VAP, and duration of mechanical ventilation before and following the onset of VAP. The final cohort included 107 patients, and one third of cases were due to MRSA. Despite receiving initially appropriate antibiotic treatment, median ICU length of stay was significantly longer for persons with MRSA infection (33 days vs. 22 days; p=.047). The median number of ICU-free days was concomitantly lower in MRSA VAP (0 days vs. 5 days; p=.011). Survival analysis employing a Cox proportional hazards model identified several predictors of remaining in the ICU: Pao2/Fio2 ratio at diagnosis of VAP, duration of MV before VAP, duration of MV after diagnosis of VAP, and reason for MV. Additionally, infection with MRSA as opposed MSSA doubled the probability of needing continued ICU care (hazard ratio, 2.08; 95% confidence interval, 1.09-3.95; p=.025). CONCLUSIONS: MRSA VAP independently prolongs the duration of ICU hospitalization, and in turn, increases overall costs, even for patients initially given appropriate antibiotic treatment. Confronting the adverse impact of MRSA will require efforts that address more than the initial antibiotic prescription.
Link: Is it possible
AIM: There is an increasing incidence of methicillin resistant Staphylococcus Aureus (MRSA) following vascular surgery, which is associated with poor outcome. The risk factors and timing for MRSA acquisition have been established. We attempt to establish predictors of outcome in MRSA positive patients undergoing arterial reconstruction. METHODS: Eighty-five MRSA positive patients who underwent arterial surgery were grouped according to outcome: good outcome group (successful revascularisation) or poor outcome group (major limb amputation or death). Seven variables were compared: age, gender, renal function, co-morbidity, positive swab site, incision site and second revascularisation surgery. RESULTS: Increased MRSA incidence from 1.1% to 4.6% of total admissions was highlighted over a 6 year period. When good (n=40) and poor (n=45) outcome groups were compared, no statistically significant differences were identified for the variables listed above, but a second revascularisation operation was 3 times more likely to be associated with poor outcome (P=0.09). Categorising gender and age groups suggests that male gender and age over 75 years was more likely to be associated with poor outcome (odds ratio 0.77). The results also suggest that patients having surgery involving a groin incision do worse than those who do not. One year survival of MRSA positive patients who had successful revascularisation was 90% and a significant number had MRSA eradicated. CONCLUSIONS: Although this study was unable to identify statistically significant predictors of outcome in patients with MRSA undergoing arterial reconstruction, almost half had a positive outcome. An aggressive detection and eradication policy is clearly indicated.
Link: The Annals of Pharmacotherapy.
CASE SUMMARY: A 46-year-old man (209 kg; 178 cm) failed a 42 day course of vancomycin therapy for treatment of a methicillin-resistant Staphylococcus aureus-infected wound and cellulitis. The median trough vancomycin concentration was 12.6 �g/mL (range 7.3-24.1) through his course of therapy. Estimation of creatinine clearance (Clcr ) was confounded in this clinical scenario, given the patient's weight and a lack of valid equations in this patient population. Daptomycin was administered empirically at 6 mg/kg dosed every 48 hours based on estimated clearance from measured vancomycin concentrations. Steady-state plasma concentrations of daptomycin were determined, and the daptomycin half-life in this patient was more accurately estimated using vancomycin clearance as a surrogate. In addition, a 4 mg/kg dose of daptomycin would have been sufficient based on plasma concentrations. The patient demonstrated rapid clinical improvement and remained free of cellulitis for 6 months after completion of daptomycin and a 12 week course of trimethoprim/sulfamethoxazole. DISCUSSION: The dosing interval of daptomycin is adjusted based on Clcr. However, estimation of Clcr is difficult in morbidly obese patients with renal impairment, given a lack of valid equations. In this clinical scenario, vancomycin concentrations were used to estimate Clcr and served as a surrogate measure to determine the daptomycin dosing interval. Measured daptomycin concentrations validated this approach and confirmed the inadequacy of commonly used Clcr equations. CONCLUSIONS: In this clinical scenario, vancomycin concentrations more accurately estimated Clcr, thereby facilitating determination of the daptomycin dosing interval.
Link: Nosocomial pneumonia
Studies that have appeared since the ATS statement issued in 1996, demonstrate several new risk factors for HAP with multiresistant pathogens. In patients with risk factors, empirical therapy should consist of antibacterials with a broader spectrum. The most important risk factors for resistant microorganisms are late onset of HAP (>/=5 days after admission), recent use of antibacterial therapy, and mechanical ventilation. Multiresistant bacteria of specific interest are methicillin-resistant S. aureus (MRSA), Pseudomonas aeruginosa, Acinetobacter calcoaceticus-baumannii, Stenotrophomonas maltophilia and extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae. Each of these organisms has its specific susceptibility pattern, demanding appropriate antibacterial treatment. To further improve outcomes, specific therapeutic options for multiresistant pathogens and pharmacological factors are discussed. Antibacterials developed since 1996 or antibacterials with renewed interest (linezolid, quinupristin/dalfopristin, teicoplanin, meropenem, new fluoroquinolones, and fourth-generation cephalosporins) are discussed in the light of developing resistance.Since the ATS statement, many reports have shown increasing incidences of resistant microorganisms. Therefore, one of the most important conclusions from this review is that empirical therapy for HAP should not be based on general guidelines alone, but that local epidemiology should be taken into account and used in the formulation of local guidelines.
Link: Designs For Wellbeing.
Bio-active textiles
This technology bonds copper compounds to fabrics, paper etc., therefore giving them powerful, long-lasting antimicrobial properties without causing any harm - e.g. clothing for surgeons, pyjamas, sheets. Foot infections: Socks are now standard issue for US Marines - "the rough and tough guys are wearing our socks" - "no smell". Bird flu? "so the mask that we have will kill - actually destroy the virus when it comes in contact with it." "This is a mask that is going to cost almost the same as a normal mask." "This will be made for general distribution." HCAIs? "We have the same kind of thing that we've done for surgeons." "Sheets that kill bacteria will go a long way towards solving the problem of infections acquired in hospitals."
Link: Stevens et al., Guidelines for Skin and Soft-Tissue Infections.
Emerging antibiotic resistance among Staphylococcus aureus (methicillin resistance) and Streptococcus pyogenes (erythromycin resistance) are problematic, because both of these organisms are common causes of a variety of skin and soft-tissue infections and because empirical choices of antimicrobials must include agents with activity against resistant strains. Minor skin and soft-tissue infections may be empirically treated with semisynthetic penicillin, first-generation or second-generation oral cephalosporins, macrolides, or clindamycin (A-I); however, 50% of methicillin-resistant S. aureus (MRSA) strains have inducible or constitutive clindamycin resistance [2] (table 1). Most community-acquired MRSA strains remain susceptible to trimethoprim-sulfamethoxazole and tetracycline, though treatment failure rates of 21% have been reported in some series with doxycycline or minocycline [3]. Therefore, if patients are sent home receiving these regimens, it is prudent to reevaluate them in 24–48 h to verify a clinical response. Progression despite receipt of antibiotics could be due to infection with resistant microbes or because a deeper, more serious infection exists than was previously realized. Table 1. Infectious Diseases Society of America–US Public Health Service Grading System for ranking recommendations in clinical guidelines. Patients who present to the hospital with severe infection or whose infection is progressing despite empirical antibiotic therapy should be treated more aggressively, and the treatment strategy should be based upon results of appropriate Gram stain, culture, and drug susceptibility analysis. In the case of S. aureus, the clinician should assume that the organism is resistant, because of the high prevalence of community-associated MRSA strains, and agents effective against MRSA (i.e., vancomycin, linezolid, or daptomycin) should be used (A-I). Step-down to treatment with other agents, such as tetracycline or trimethoprim-sulfamethoxazole, for MRSA infection may be possible, based on results of susceptibility tests and after an initial clinical response.Link: Nosocomial
A 36-year-old, 7-week-gravida patient with catheter-related nosocomial infective endocarditis due to methicillin-resistant Staphylococcus aureus (MRSA) is presented in this paper. The patient was admitted to our hospital because of carbon monoxide intoxication. After 14 days, MRSA catheter-related bacteremia developed. The central venous catheter was immediately removed, and teicoplanin therapy was started. Because of persistent fever, leukocytosis, and high C-reactive protein values, endocarditis was suspected. A transesophageal echocardiogram revealed 19-mm vegetation on her mitral valve, confirming the diagnosis of endocarditis. Gentamicin and rifampicin were added to the therapy regimen, and the dose of teicoplanin was increased to 12 mg/kg-day. After 8 days, a splenic abscess was detected by ultrasonography. Vegetation excision, mitral valve replacement by open-heart surgery and splenectomy were performed in the same operation. Antibiotherapy was continued for 6 weeks after surgery, and the patient's condition improved. The development of endocarditis could be prevented by proper clinical practices.
The crude hospital mortality rate was higher for MRSA-infected patients than for MSSA-infected patients (59.4% vs. 40%; P = .024). This difference disappeared after controlling for time in the ICU before VAP and parameters imbalanced at ICU admission (odds ratio [OR], 1.23; 95% confidence interval [CI], 0.49-3.12; P = .7) and remained unchanged after further adjustments for initial treatment adequacy and polymicrobial VAP (OR, 0.98; 95% CI, 0.36-2.66). CONCLUSIONS: Differences in patient characteristics, initial ICU treatment, and time in the ICU confounded estimates of excess death due to MRSA VAP. After careful adjustment, methicillin resistance did not affect ICU or hospital mortality rates.
Link: HighWire Press -- Medline Abstract.
At the University Medical Center Utrecht (UMCU), follow-up implies an inventory of risk factors and screening for MRSA colonization among all MRSA-positive patients for at least 6 months. If risk factors or positive cultures persist or re-emerge, longer follow-up is indicated and isolation at readmission. This study investigated how long MRSA-positive patients remained colonized after hospital discharge and which risk factors were important. Furthermore, the results of eradication therapy were evaluated. A total of 135 patients were included in the study. The median follow-up time was 1.2 years. Eighteen percent of the patients were dismissed from follow-up 1 year after discharge. Only 5 patients were dismissed after 6 months. Among patients with no risk factors, eradication treatment was effective for 95% within 1 year. Among patients with persistent risk factors, treatment was effective for 89% within 2 years. CONCLUSIONS: Based on these findings, eradication therapy should be prescribed for all MRSA carriers, independent of the presence of risk factors. MRSA-positive patients should be evaluated for 6 months for the presence of risk factors and MRSA carriage. Screening for risk factors is important because intermittent MRSA carriage was found in a significant number of our patients. Patients with negative MRSA cultures and without risk factors for 12 months can be safely dismissed from follow-up.
Link: Infection Control Nurses Asociation.
CONSULTATION: Guidelines for the prophylaxis and treatment of meticillin (methicillin)-resistant Staphylococcus aureus (MRSA) infections in the United Kingdom Produced by a joint working party of the British Society for Antimicrobial Chemotherapy, Hospital Infection Society and Infection Control Nurses Association, these draft guidelines are being issued for open consultation for a period of four weeks commencing Monday 11 April 2005.
Link: Treatment of staphylococcal infection -- Amyes 330 (7498): 976 -- BMJ.
The emergence and spread of modern resistant bacteria are not simply the result of mutations or gene transfer in the diverse species we call S aureus,2 as occurred when resistance first developed.3 Instead the resistance is now spread by the dissemination of a tiny number of clones, which have a predisposition towards resistance and have been selected by current treatment. So how does one treat staphylococcal infection? In particular, two clones, epidemic MRSA (EMRSA)-15 and EMRSA-16, account for more than 95% of MRSA strains isolated in the United Kingdom.4 The carriage of resistance in these bacteria seems to be associated with no fitness cost
Link: Review of 10 cases..
We evaluated retrospectively, 10 MRSA meningitis cases in our hospital that occurred between January 1999 and June 2004. All were post-neurosurgical and were considered to have hospital-acquired meningitis. Fever, leukocytosis, variable conscious levels were the most common findings. Six patients were treated with regimens including teicoplanin, and four with vancomycin. Mean duration of treatment was 23.5 /-18.8 days (range, 3-60 days). One patient died. In cases of MRSA meningitis, intravenous vancomycin is the mainstay of therapy. However, six of these 10 patients were successfully treated with regimens including teicoplanin, suggesting that this agent may be an alternative to vancomycin in the therapy of these cases.
Link: HighWire Press -- Medline Abstract.
We describe the successful selective coil embolization of an infected superior gluteal pseudoaneurysm secondary to methicillin-resistant Staphylococcus aureus (MRSA) in a 36-year old women. The patient presented with a long history of drug abuse and perisacral abscesses due to chronic sacroilitis. The chosen strategy provides a safe and successful management of infected false gluteal artery aneurysm.
Medscape
Below is the conclusion of a very detailed analysis of the impact of MRSA. The whole article is worth reading for those keen to understand the full extent of the current research
Compared with MSSA, MRSA is associated with worse outcomes, including longer hospital and ICU stays, longer durations of mechanical ventilation, and higher mortality rates. In addition, the cost of treating patients with bacteremia due to MRSA is higher. Inadequate antibiotic therapy is common, is associated with significant mortality, and perhaps explains why outcomes in MRSA infection are so poor. Emerging data suggest that therapy with vancomycin is less than optimal; treatment failure and mortality rates are substantial whether the cause of bacteremia is MRSA or MSSA. Because MRSA is far more common in healthcare-related or nosocomial bacteremia than in community-acquired bacteremia, empiric antibiotic therapy for patients with healthcare-related bacteremia should include coverage for MRSA.
HighWire -- Medline Abstract
In a phase II study the urinary bactericidal activity of linezolid versus ciprofloxacin in volunteers showed comparable activity of both drugs against fluoroquinolone susceptible Gram-positive uropathogens, whereas linezolid was also as active against fluoroquinolone resistant ones.
A short introduction from Dave Roberts
This 12 minute introduction will help you grasp the key facts and the key issues surrounding drug resistant staph aureus (mersa, mursa)
