MRSA (Mersa, Staph) Questions

Green Tea Proves Powerful Medicine Against Sepsis

Link: Green Tea Proves Powerful Medicine Against Sepsis.

A major component of green tea could prove the perfect elixir for severe sepsis, an abnormal immune system response to a bacterial infection. In a new laboratory study, Haichao Wang, PhD, of The Feinstein Institute for Medical Research, and his colleagues have been studying the therapeutic powers of dozens of Chinese herbal compounds in reversing a fatal immune response that kills 225,000 Americans every year. They found that an ingredient in green tea rescued mice from lethal sepsis – and the findings could pave the way to clinical trials in patients. The study was published this week in the Public Library of Science, or PLoS-ONE. Wang had previously discovered a late mediator of sepsis called HMGB1, a substance expressed in the late stages of lethal sepsis. They wanted to figure out a way to block this substance, which they felt would prevent the lethal sepsis process from moving forward. And it worked. Scientists worldwide have been stumped by sepsis. Even with the most advanced medical techniques available, half of those who develop sepsis die of the massive assault on the body.

Revolutionary Laser Technique Destroys Bacteria

Link: Revolutionary Laser Technique Destroys Viruses And Bacteria Without Damaging Human Cells.

Physicists in Arizona State University have designed a revolutionary laser technique which can destroy viruses and bacteria such as AIDS without damaging human cells and may also help reduce the spread of hospital infections such as MRSA. The research, published on Thursday November 1 in the Institute of Physics' Journal of Physics: Condensed Matter, discusses how pulses from an infrared laser can be fine-tuned to discriminate between problem microorganisms and human cells. Current laser treatments such as UV are indiscriminate and can cause ageing of the skin, damage to the DNA or, at worst, skin cancer, and are far from 100 per cent effective.

Research Conference That Will Facilitate Development Of New Treatments For MRSA

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.

Shining a light on an alternative treatment for MRSA

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.

Photodynamic therapy of microbial infections

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.

Two cases of parotid gland infection with bacteraemia due to MRSA

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.

Guidelines for the prophylaxis and treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections in the UK -- Gemmell et al. 57 (4): 589 -- Journal of Antimicrobial Chemotherapy

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.

MRSA adds 505 to ICU recovery time

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.

Is it possible to predict outcome in MRSA positive patients undergoing arterial reconstruction?

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.

Using Vancomycin Concentrations for Dosing Daptomycin

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.