MRSA, Staph, Staff, Mersa, Methicillin Resistant Staphylococcus Aureus Symptoms & Treatment

Indonesia has very high PVL MRSA rates

Link: HighWire Press -- Medline Abstract.

Few data on the molecular characteristics and epidemiology of Staphylococcus aureus from Indonesia are available. The purpose of the present study was to define S. aureus reservoirs in both the Indonesian community and the hospital using a collection of 329 nasal carriage isolates obtained during a survey of 3,995 healthy individuals and patients from Java, Indonesia. Only one strain (0.3%) was identified as methicillin-resistant S. aureus (MRSA) by mecA gene PCR. The Panton-Valentine leukocidin (PVL) genes were detected in 35 methicillin-sensitive S. aureus (MSSA) strains (10.6%). Molecular typing by pulsed-field gel electrophoresis of the 329 isolates showed extensive genetic diversity among both PVL-positive and PVL-negative strains. In Surabaya, however, a cluster was identified that was strongly associated with the presence of the PVL locus (P < 0.0001). As determined by high-throughput amplified fragment length polymorphism (AFLP), PVL-positive strains occurred throughout all major AFLP clusters (I-IV). Multilocus sequence typing of a subset of isolates showed that most PVL-positive strains belonged to sequence type (ST) 188, while most PVL-negative isolates belonged to ST4The high prevalence of PVL-positive S. aureus strains in certain regions of Indonesia is of concern since these strains may cause severe infections in the community and in hospitals.

Norwegians struggle to eradicate PVL MRSA in patients

Link: HighWire Press -- Medline Abstract.

BACKGROUND: Staphylococcus aureus is a frequent cause of serious infections. Methicillin-resistant S. aureus (MRSA) are resistant to almost all types of beta-lactam antibiotics and therefore represent a substantial medical problem. MATERIAL AND METHOD: In April 2006, the Department of Obstetrics at the Asker and Baerum hospital had an outbreak of MRSA that affected four newborns. The source for the infection was sought among family members, other patients and employees, and eradication was attempted. RESULTS: An employee was identified as the probable infectious source. Subsequent investigation identified 13 individuals infected by the same MRSA clone, which was Panton-Valentine-leukocidin (PVL) positive and therefore clearly a pathogen. 10 of the patients had MRSA disease, with 21 months between the first and the last identified case. For 5 of 13 patients MRSA was still detectable after the first attempt of eradication. For 2 patients, including one of the newborns, eradication has so far been unsuccessful and a third patient has acquired a new abscess after one year. INTERPRETATION: Issues connected to MRSA-screening of close contacts and eradication are resource-demanding and require careful consideration of strategy, especially for small children and families with chronic MRSA carriers. Updated detailed national guidelines for MRSA management are needed.

PVL MRSA a Problem in Mali

Link: The carriage population of Staphylococcus aureus from Mali is composed of a combination of pandemic clones and the divergent PVL positive genotype ST152 -- Ruimy et al., 10.1128/JB.01947-07 -- The Journal of Bacteriology.

Staphylococcus aureus is an important human pathogen, but asymptomatic colonisation of the naso-pharynx is far more common than cases of invasive disease. Evidence concerning the global population structure of S. aureus is limited by the over-representation in the database of disease isolates recovered from Western Europe, the Americas, Australia and Japan. We address this by presenting data from the carriage population in Mali, the first detailed characterisation of asymptomatic carriage from an African population. These data confirm the pandemic spread of many of the common S. aureus clones in the carriage population. We also note the high frequency (~24%) of a single divergent genotype, ST152, which has not previously been recovered from nasal carriage, but which corresponds to a sporadic PVL positive CA-MRSA clone noted in mostly in central Europe. We show that 100% of the ST152 isolates recovered from nasal carriage in Mali are PVL positive and discuss implications relating to the emergence and spread of this virulent genotype.

6 hit by PVL MRSA in Essex Hospital

Link: The Dunmow Broadcast - MRSA outbreak.

A SECOND outbreak of MRSA has been discovered at an Essex hospital, which has affected six people. Last Wednesday the St Andrews Burns Unit in Broomfield Hospital, Chelmsford, discovered that six patients had tested positive for the presence of panton-valentine leukocidin (PVL), a rare strain of MRSA. Of the six patients affected, four have been discharged and are said to be in good health at home. One is still inside the unit recovering from a serious burn, but not unwell due to his contracting of PVL. The sixth patient, who has since died, had suffered from a major burn - a post mortem is expected to reveal if the patient's death was related to PVL. It is the second incident of the bacteria at the hospital in less than six months - two patients tested positive for the strain in October last year, but successfully underwent treatment. Mid Essex Hospitals NHS Trust spokesman Martin Cresswell said: "Following the outbreak in October last year we have been continually monitoring swabs of everyone who uses the unit.

Genetic insight into the origins of PVL MRSA

Link: HighWire Press -- Medline Abstract.

Background. @nbsp; The majority of recent community-associated methicillin-resistant Staphylococcus aureus (MRSA) infections in the United States have been caused by a single clone, USA300. USA300 secretes Panton-Valentine leukocidin (PVL) toxin, which is associated with highly virulent infections. Methods. @nbsp; We sequenced the PVL genes of 174 S. aureus isolates from a global clinical sample. We combined phylogenetic reconstruction and protein modeling methods to analyze genetic variation in PVL. Results. @nbsp; Nucleotide variation was detected at 12 of 1726 sites. Two PVL sequence variants, the R variant and the H variant, were identified on the basis of a substitution at nt 527. Of sequences obtained in the United States, 96.7% harbor the R variant, whereas 95.6% of sequences obtained outside the United States harbor the H variant; 91.3% of MRSA isolates harbor the R variant, and 91.3% of methicillin-susceptible strains harbor the H variant. A molecular model of PVL shows 3 mechanisms by which the amino acid substitution may affect PVL function. Conclusions. @nbsp; All sampled PVL genes appear to share a recent common ancestor and spread via a combination of clonal expansion and horizontal transfer. US isolates harbor a variant of PVL that is strongly associated with MRSA infections. Protein modeling reveals that this variant may have functional significance. We propose a hypothesis for the origin of USA300. PMID: 18177252

Infection by Panton Valentine leukocidin-producing Staphylococcus aureus clinically mimicking Lemierre's syndrome

Link: Infection by Panton Valentine leukocidin-producing Staphylococcus aureus clinically mimicking Lemierre's syndrome -- Shivashankar et al. 57 (1): 118 -- Journal of Medical Microbiology.

Lemierre's syndrome is an oropharyngeal infection which leads to severe septic thrombophlebitis of the internal jugular vein and metastatic abscesses of the lungs and other organs. It is usually caused by Fusobacterium necrophorum, a Gram-negative obligate anaerobe. An unusual case of Panton–Valentine leukocidin (PVL)-producing Staphylococcus aureus infection masquerading as Lemierre's syndrome is reported here. A 32-year-old fit and otherwise healthy male presented on Christmas morning with a boil on his left cheek for 2 days and generalized rash for 3 h. His general condition began to worsen, he developed facial swelling and loss of vision in the left eye and was transferred to the intensive care unit. His treatment was taken over by team of specialists and further investigations revealed thrombophlebitis of the left internal jugular vein and cavernous sinus thrombosis with multiple brain infarcts and lung abscesses. His condition remained critical with multiple cranial nerve involvement despite being on broad-spectrum antibiotics. Blood cultures grew S. aureus which was producing PVL toxin. He improved gradually over several weeks. He underwent intensive physiotherapy and made a good recovery. Although a rare entity, it is important to consider Lemierre's syndrome in septic patients who present with rapidly worsening symptoms.

Rare CA MRSA Strains Not as Robust as PVL Variants

Link: Sporadic "Transitional" Community-Associated Methicillin-Resistant Staphylococcus aureus Strains from Health Care Facilities in the United States -- Brady et al. 45 (8): 2654 -- Journal of Clinical Microbiology.

We describe phenotypic and genotypic traits of a group of methicillin-resistant Staphylococcus aureus (MRSA) clones that are either remnants of unsuccessful community-associated MRSA (CA-MRSA) clones or represent a transitional state with some yet-to-be-acquired characteristics of CA-MRSA. These rare strains (n = 20) were identified during a 10-year period (1990-1999) from 13 unrelated health care facilities in Wisconsin. The isolates were recovered from patients in nosocomial or long-term chronic care facilities (60%) and outpatient settings (40%). Sixty percent (n = 12) of the isolates were recovered from skin and soft tissue infections, whereas the remaining isolates (n = 8) were from invasive infections. Ninety percent of isolates were susceptible to all antibiotic classes tested or resistant to erythromycin and clindamycin. Pulsed-field gel electrophoresis, multilocus sequence typing, and spa typing clustered these isolates into 8, 8, and 14 clonal groups, respectively. Eight plasmid profiles were represented in these strains. All four agr types were represented, with type IV being predominant (40%). All strains harbored subtypes of type IV staphylococcal cassette chromosome mec but lacked genes for the virulence factor Panton-Valentine leukocidin (PVL). The strains harbored one or more of the following toxin genes: sea, seb, sec, sed, see, seh, sej, sek, sel, seg, sei, sem, sen, and seo. Individual clonal groups maintained the same set of enterotoxin genes even though they were isolated over extended time periods, suggesting significant genomic stability. The potential role of PVL-carrying phages and plasmids in the success of CA-MRSA clones has been discussed.

Diverse CA MRSA Strains Found in Ireland

Link: The Emergence and Importation of Diverse Genotypes of Methicillin-Resistant Staphylococcus aureus (MRSA) Harboring the Panton-Valentine Leukocidin Gene (pvl) Reveal that pvl Is a Poor Marker for Community-Acquired MRSA Strains in Ireland -- Rossney et al. 45 (8): 2554 -- Journal of Clinical Microbiology.

This study investigated MRSA isolates from Ireland (CA-MRSA, health care-associated MRSA, and HA-MRSA) for the carriage of pvl and determined the genotypic characteristics of all pvl-positive isolates identified. All 1,389 MRSA isolates were investigated by antibiogram-resistogram typing and SmaI DNA macrorestriction analysis. pvl-positive isolates were further characterized by multilocus sequence typing and SCCmec, agr, and toxin gene typing. Twenty-five (1.8%) MRSA isolates belonging to six genotypes (ST30, ST8, ST22, ST80, ST5, and ST154) harbored pvl. Nineteen of these (76%) were CA-MRSA isolates, but a prospective study of MRSA isolates from 401 patients showed that only 6.7% (2/30) of patients with CA-MRSA yielded pvl-positive isolates. Thus, pvl cannot be used as a sole marker for CA-MRSA. Fifty-two percent of pvl-positive MRSA isolates were recovered from patients with skin and soft tissue infections; thirty-six percent were from patients of non-Irish ethnic origin, reflecting the increasing heterogeneity of the Irish population due to immigration. All 25 pvl-positive isolates carried SCCmec IV; 14 (56%) harbored SCCmec IV.1 or IV.3, and the remaining 11 isolates could not be subtyped. This study demonstrates that pvl is not a reliable marker for CA-MRSA in Ireland and reveals the emergence and importation of diverse genotypes of pvl-positive MRSA in Ireland.

PVL deep tissue infection hitting children

Link: Occult Methicillin-Resistant Staphylococcus aureus Abscesses in 2 Pediatric Patients -- Feder, 10.1177/0009922807306056 -- Clinical Pediatrics.

Methicillin-resistant Staphylococcus aureus (MRSA) infections have become more common over the last decade. Recently, severe MRSA infections including necrotizing pneumonia, purpura fulminans, and rapidly progressive skin abscesses have been reported. These severe infections frequently have been associated with the virulence factor Panton-Valentine leukocidin (PVL). Two unusual cases of occult deep tissue abscesses in children who had family members with a history of severe MRSA skin abscesses are presented in this article. Both children initially presented with fever without a focus. Deep tissue MRSA (PVL positive) abscesses evolved. Empiric antibiotic therapy for MRSA should be considered for infants and children who are hospitalized with occult fever and who have a family member with a history of MRSA infection.

CA MRSA attacks brain in Egyptian patient

Link: .

Isolated MRSA was positive for PVL, belonged to ST30 and agr3, and had SCCmecV. The MIC value of oxacillin for this MRSA was low (8 �g/mL), and MRSA was susceptible to non-beta-lactam antimicrobial agents. These data of the molecular characteristics and drug susceptibility, together with the fact that MRSA was isolated from the abscess, are in close agreement with CA-MRSA. A case of a brain abscess due to CA-MRSA has been previously reported, although with no description about the presence of the PVL gene in MRSA [13]. To the best of our knowledge, this study demonstrates the first case of a brain abscess due to PVL-positive MRSA and also the first isolation of CA-MRSA in Egypt. Since CA-MRSA is highly virulent and can spread in the community as well as within hospitals [3,14], surveillance for PVL-positive MRSA (CA-MRSA) should be actively performed in Egypt.