Household transmission of meticillin-resistant Staphylococcus aureus and other staphylococci.

Sept 2012

Davis MF, Iverson SA, Baron P, Vasse A, Silbergeld EK, Lautenbach E, Morris DO.

Source

Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD USA.

Abstract

Although the role of pets in household transmission of meticillin-resistant Staphylococcus aureus (MRSA) has been examined previously, only minor attention has been given to the role of the abiotic household environment independent of, or in combination with, colonisation of pets and human beings to maintain transmission cycles of MRSA within the household. This report reviews published work about household transmission of S aureus and other staphylococci and describes contamination of household environmental surfaces and colonisation of pets and people. Household microbial communities might have a role in transfer of antimicrobial resistance genes and could be reservoirs for recolonisation of people, although additional research is needed regarding strategies for decontamination of household environments. Household-based interventions should be developed to control recurrent S aureus infections in the community, and coordination between medical and veterinary providers could be beneficial.

Science Direct

Successful management of methicillin-resistant Staphylococcus aureus bacteremia unresponsive to Vancomycin by adding fosfomycin: a case report.

Jul 2012

Linasmita P.

Source

Division of Infectious Disease, Department of Medicine, Faculty ofMedicine, HRH Princess Maha Chakri Sirindhorn Medical Center, Srinakharinwirot University, Nakhon Nayok, Thailand. paul_lin_md@yahoo.com

Abstract

BACKGROUND:

Vancomycin is the drug of choice for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) bacteremia. However, vancomycin treatment failures are occasionally observed with some strains that are considered susceptible to vancomycin according to Clinical and Laboratory Standards Institute breakpoints (vancomycin minimum inhibitory concentration [MIC] < or =2 microg/mL). Although fosfomycin has in vitro activity against MRSA, clinical data regarding the use of fosfomycin either alone or in combination for the management of MRSA bacteremia is limited.

CASE REPORT:

A 57-year-old woman who was on regular hemodialysis for chronic kidney disease presented with sepsis associated with possible infection of arteriovenous fistula. Blood culture grew MRSA with vancomycin MIC of 1.5 microg/mL. Despite placement of a double-lumen catheter for hemodialysis and treatment with vancomycin and serum concentrations monitoring to keep trough levels of 15 to 20 microg/mL, her blood cultures still continued to grow MRSA for over 10 days. Later intravenous fosfomycin was added to the regimen along with vancomycin. After three days of this combination, suppression of bacteremia was achieved.

CONCLUSION:

Combination of fosfomycin and vancomycin might be another option for the treatment of bacteremia due toMRSA with vancomycin MIC of 1.5 microg/mL that is not responsive to vancomycin alone.

PubMed

Review of a major epidemic of methicillin resistant Staphylococcus aureus: The costs of screening and consequences of outbreak management.

Aug 2012

van der Zee A, Hendriks WD, Roorda L, Ossewaarde JM, Buitenwerf J.

Source

Molecular Diagnostics Unit, Maasstad Hospital, Rotterdam, The Netherlands.

Abstract 

BACKGROUND:

A major outbreak of methicillin-resistant Staphylococcus aureus (MRSA) occurred in locations C and Z of our hospital and lasted for several years. It affected 1,230 patients and 153 personnel.

METHODS:

Outbreak management was installed according to the Dutch "search and destroy" policy. A rapid, high-throughput method for molecular screening of potential MRSA carriers was implemented. Outbreak isolates were retrospectively genotyped by pulsed field gel electrophoresis. Costs of molecular screening were compared with screening by culture.

RESULTS:

Genotyping results revealed 4 distinct epidemic MRSA clones. Three were present in hospital C. Because of a merger of hospitals, these clones spread to hospital Z. Another clone of MRSA affected other health care-related institutions in the region. Because of the implementation of strict containment measures of the "search and destroy" policy, the annual number of tests decreased from 100,000 to 18,000. The disposables and reagents used in polymerase chain reaction technology are more expensive than those of conventional methods. However, the clinical and economic benefits of fast results in regard to expenses of the hospital clearly outweigh the higher costs of screening.

CONCLUSION:

The implementation of a rapid, high-throughput molecular screening system greatly contributed to the effectiveness of strict containment measures of the "search and destroy" policy. The major epidemic clones of MRSA in the outbreak were eradicated by this strategy.

PubMed

A delivery system of linezolid to enhance the MRSA osteomyelitis prognosis: in vivo experimental assessment.

Aug 25, 2012

Gaudin A, Jacqueline C, Gautier H, Desessard C, Le Mabecque V, Miegeville AF, Potel G, Bouler JM, Weiss P, Caillon J,Amador G.

Source

Faculté de Médecine, UPRES EA 3826, Université de Nantes, 1 rue Gaston Veil, Nantes, 44000, France.

Abstract

Staphylococcus aureus, a major responsible microorganism of osteomyelitis, represents a challenge to treat because of the poor penetration of antibiotics in bone and increasing minimum inhibitory concentrations (MICs) to glycopeptides. The calcium-deficient apatites (CDA), closer to the biological components found in bone and other calcified tissues, have osteoconductive properties. So, to process severe osseous infections, CDA can be used to deliver in the infectious site antibiotics like linezolid. The acute experimental osteomyelitis due to methicillin-resistant Staphylococcus aureus (MRSA) was induced in rabbit's femurs and surgery mimicking human procedures was performed at day three after inoculation. Animals were randomly assigned to treatment groups: L((IV)) [4-day linezolid IV infusion, human-equivalent dose of 10 mg/kg/12 h], L((CDA50%)) (100 mg CDA with linezolid 500 μg/mg) and L((CDA50%)) + L((IV)). Surviving bacteria were counted in bone marrow (BM) and bone (Bo) at day 3 (before treatment), day 7 (4-day treatment) or day 17 (14-day treatment). L(iv) was effective after a 4-day treatment with a log(10)CFU/g decrease of -2.63 ± 1.92 and -2.17 ± 1.58 in bone marrow and bone, respectively. CDA loaded with linezolid enhance the efficacy of the IV linezolid regimen by more than one log(10)CFU/g.

PubMed