Increase in the frequency of community-acquired methicillin-resistant Staphylococcus aureus clones among inpatients of acute care hospitals in the Kyoto and Shiga regions, Japan.

BACKGROUND: Specific epidemic clones of hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) are responsible for the worldwide spread of MRSA. However, in recent years, the isolation of community-acquired MRSA (CA-MRSA) clones has been increasing. We investigated the latest molecular epidemiology trends of HA-MRSA and CA-MRSA clones in the Kyoto and Shiga regions, Japan. MATERIALS AND METHODS: All nonduplicate MRSA isolates obtained from the clinical specimens of inpatients at four acute care hospitals in the Kyoto and Shiga regions between 2014 and 2019 were typed using the PCR-based open reading frame typing (POT) method. CA-MRSA and HA-MRSA were classified according to the POT1 values. We performed whole-genome sequencing analysis for representative isolates displaying common POT types. RESULTS: A total of 2413 isolates were included in the study, comprising 1730 nosocomial and 683 nonnosocomial isolates. The rates of HA-MRSA decreased from 50.2% in 2014 to 19.0% in 2019, while those of CA-MRSA increased from 44.7% to 76.4% (p < 0.001). Isolates belonging to the most common 10 POT types (CA-MRSA, n = 6; HA-MRSA, n = 4) accounted for 42% of the isolates studied and were obtained from 3 or more hospitals. Whole-genome sequencing analysis showed that the common CA-MRSA isolates with POT types 106-137-80, 106-9-80, 106-9-2, and 106-137-2, those with POT types 106-183-37 and 106-129-5, and HA-MRSA isolates with POT types 93-191-103, 93-157-127, 93-137-103, and 93-223-111 belonged to ST8-SCCmecIV, ST1-SCCmecIV, and ST764-SCCmecII, respectively. CONCLUSION: A recent clonal shift from HA-MRSA to CA-MRSA occurred, and specific regional clones were prevalent among inpatients in the Kyoto and Shiga regions.

Antibiotic use among twelve Canadian First Nations communities: a retrospective chart review of skin and soft tissue infections.

BACKGROUND: Previous publications indicated an emerging issue with community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA), particularly skin and soft tissue infections (SSTIs), in Indigenous communities in Canada. The objectives of this analysis were to explore the prevalence of SSTIs due to CA-MRSA and patterns of antimicrobial use in the community setting. METHODS: A retrospective chart review was conducted as part of an environmental scan to assess antibiotic prescriptions in 12 First Nations communities across five provinces in Canada including Alberta, Saskatchewan, Manitoba, Ontario, and Québec. Charts were randomly selected from nursing stations and patients who had accessed care in the previous 12 months and were ≥ 18 years were included in the review. Data was collected from September to December, 2013 on antibiotic prescriptions, including SSTIs, clinical symptoms, diagnostic information including presence of CA-MRSA infection, and treatment. RESULTS: A total of 372 charts were reviewed, 60 from Alberta, 70 from Saskatchewan, 120 from Manitoba, 100 from Ontario, and 22 from Québec. Among 372 patients, 224 (60.2%) patients had at least one antibiotic prescription in the previous 12 months and 569 prescriptions were written in total. The prevalence of SSTIs was estimated at 36.8% (137 cases of SSTIs in 372 charts reviewed). In 137 cases of SSTIs, 34 (24.8%) were purulent infections, and 55 (40.2%) were due to CA-MRSA. CONCLUSIONS: This study has identified a high prevalence of antibiotic use and SSTIs due to CA-MRSA in remote and isolated Indigenous communities across Canada. This population is currently hard to reach and under-represented in standard surveillance system and randomized retrospective chart reviews can offer complimentary methodology for monitoring disease burden, treatment and prevention.

The first nationwide surveillance of antibacterial susceptibility patterns of pathogens isolated from skin and soft-tissue infections in dermatology departments in Japan.

To investigate the trends of antimicrobial resistance in pathogens isolated from skin and soft-tissue infections (SSTI) at dermatology departments in Japan, a Japanese surveillance committee conducted the first nationwide survey in 2013. Three main organisms were collected from SSTI at 30 dermatology departments in medical centers and 10 dermatology clinics. A total of 860 strains - 579 of Staphylococcus aureus, 240 of coagulase-negative Staphylococci, and 41 of Streptococcus pyogenes - were collected and shipped to a central laboratory for antimicrobial susceptibility testing. The patient profiles were also studied. Among all 579 strains of S. aureus, 141 (24.4%) were methicillin-resistant (MRSA). Among 97 Staphylococcus epidermidis strains, 54 (55.7%) were methicillin-resistant (MRSE). MRSA and MRSE were more frequently isolated from inpatients than from outpatients. Furthermore, these methicillin-resistant strains were also isolated more frequently from patients with histories of taking antibiotics within 4 weeks and hospitalization within 1 year compared to those without. However, there were no significant differences in MIC values and susceptibility patterns of the MRSA strains between patients with a history of hospitalization within 1 year and those without. Therefore, most of the isolated MRSA cases at dermatology departments are not healthcare-acquired, but community-acquired MRSA. S. pyogenes strains were susceptible to most antibiotics except macrolides. The information in this study is not only important in terms of local public health but will also contribute to an understanding of epidemic clones of pathogens from SSTI.

[Outpatient management of community acquired meticillin resistant Staphylococcus aureus (MRSA) in Belgium]. / Prise en charge ambulatoire du Staphylococcus aureus résistant à la méticilline (MRSA) d'origine communautaire en Belgique.

Meticillin resistance is observed among S.aureus strains since 1961 and is due to the synthesis by S.aureus of a modified penicillin binding proteins named PBP2a with decreased affinity to Meticillin. Meticillin-resistant S.aureus (MRSA) strains are resistant to all betalactam antibiotics except Ceftaroline. Three epidemiological type of MRSA are now described globally in Europe and certainly in Belgium. These different types of MRSA differ by their genetic composition, the presence of virulence factors, their transmissibility, their clinical picture and their sensitivity to ant ibiot ics. The first one are the hospi tal associated MRSA strains (HA-MRSA) that causes pneumonia, urinary tract infection or bacteremia mostly among old patients presenting multiple comorbidities. Multiresistance to antibiotics is frequent in HA-MRSA and treatment of HA-MRSA related infections usually necessitate hospitalization of the patient. The second type of MRSA is a livestock associated MRSA (LA-MRSA). At risk persons are person living in close contact to livestock as farmers and veterinarians). The third type of MRSA is the community associated MRSA (CA-MRSA) described among individuals with little or no exposure to healthcare facilities. CAMRSA has been recognized in Belgium since 2003. In more than 80 % of cases, it is responsible for skin and soft tissue infections such as abscesses, furuncles and purulent cellulitis in otherwise healthy individuals. A great proportion of the CA-MRSA strains carry the Panton- Valentine leukocidin gene, a severity factor of S.aureus infections. In Belgium up to 6 % of acute skin and soft tissue are due to CA-MRSA. Recurrent infections and transmission among household members are frequently described. Incision and drainage is the primary treatment of CA-MRSA associated abscesses. Antibiotic therapy is recommended only in patient with severe infect ions or with underlying comorbidities. CA-MRSA is usually susceptible to non betalactam antibiotics. Recommended antibiotics, if antibiogram shows the strain is suceptible to the drug, are clindamycin, doxycycl in and cotrimoxazole. Prevent ive educational messages on personal hygiene and appropriate wound care will complete the medical treatment. Decolonisation of the patient and the household members can be performed in case of recurrent lesions and/or dissemination among the family. Outbreak of CA-MRSA infections must be reported to the health inspector.

La résistance à la méticilline est décrite chez S.aureus dès 1961. Cette résistance confère une résistance à tous les antibiotiques de la famille des bêtalactames hormis la Ceftaroline. Trois origines épidémiologiques de staphylocoques résistants à la méticilline (MRSA) sont actuellement décrites globalement en Europe et certainement en Belgique. Ces différents types de MRSA sont distincts par leur composition génétique, la présence de facteurs de virulence, leur transmissibilité, le tableau clinique et leur sensibilité aux antibiotiques non bêtalactames. Il s'agit premièrement du HA-MRSA ou MRSA associé à l'hôpital qui y cause des pneumonies, infections urinaires, bactériémies surtout chez des sujets âgés et présentant des comorbidités. Ce type de MRSA est souvent résistant à de nombreux antibiotiques et son traitement nécessite l'administration d'antibiotiques à l'hôpital. Le deuxième type de MRSA, est un MRSA associé au bétail (LA-MRSA pour livestock associated MRSA). Les personnes à risque sont les personnes en contact avec les porcs et les veaux essentiellement (vétérinaires, éleveurs, personnels d'abattoir). Le troisième type de MRSA est le MRSA associé à la communauté (CAMRSA pour community associated MRSA). Observé en Belgique depuis 2003, il cause dans plus de 80 % des cas des infections des tissus mous telles qu'abcès, furoncles et cellulite suppurée. Le CA-MRSA est décrit surtout chez des individus jeunes en bonne santé. Une proportion importante de CA-MRSA sécrète la leucocidine de Panton Valentine, un facteur de gravité des infections causées par le S.aureus. En Belgique le CA-MRSA cause près de 6 % des infections aiguës des tissus mous. Des infections récurrentes ainsi que des infections multiples ausein de plusieurs membres d'un groupe ou famille sont décrites. Le traitement consiste en une incision/drainage des lésions abcédées. Des ant ibiot iques ne seront nécessaires qu'en présence de facteurs de gravité. Le CA MRSA est généralement sensible aux antibiotiques non bêtalactames actifs sur S.aureus. Les antibiotiques recommandés, si la sensibilité est démontrée à l'antibiogramme, sont le cotrimoxazole, la clindamycine et la doxycycline. Des messages éducationnels concernant l'hygiène personnelle et les soins de plaie compléteront le traitement. Une décolonisation du patient et éventuellement de son entourage peut être proposée en cas de lésions récurrentes. Les épidémies de CA-MRSA doivent être déclarées à l'inspecteur d'hygiène.

USA300 methicillin-resistant Staphylococcus aureus in Zurich, Switzerland between 2001 and 2013.

USA300 methicillin-resistant Staphylococcus aureus (MRSA) is the most prevalent MRSA in the United States of America (USA) and a global epidemic threat. We investigated the prevalence of USA300 at a tertiary care hospital in Zurich, Switzerland, where all MRSA strains have been collected and PFGE typed since 1992. These strains were retrospectively compared to the PFGE pattern of USA300 strain JE2. Isolates with a respective PFGE pattern were spa-typed and tested for the presence of the arginine catabolic mobile element (ACME) arc gene cluster and Panton-Valentine Leucocidin (PVL) genes. The first MRSA strain with a USA300 PFGE pattern was isolated in 2001 from a patient visiting from the USA. USA300 strains represented between 0% (in 2002) and 9.2% (in 2012) of all MRSA isolates in our hospital. We identified various USA300 subtypes based on either the PFGE pattern, the spa-type or absence of either the PVL genes or ACME arc gene cluster. All the USA300 strains including the variants (n=47) accounted for 5.6% of all MRSA isolates typed between 2001 and 2013 and reached a maximum of 14.5% in 2009. They predominantly caused skin and soft tissue infections (74.4%). In conclusion, even though USA300 has been present in our hospital for over twelve years it has not become the predominant MRSA clone like in the USA. However, in light of the global burden of USA300, care must be taken to further contain the spread of this lineage and of MRSA in general in our hospital.

Invasive Community-Acquired Methicillin-Resistant Staphylococcus aureus With Aortic Aneurysm in a 10-Year-Old Patient: A Case Report.

The clinical presentation of disseminated community-acquired Methicillin-resistant Staphylococcus aureus (MRSA) in young pediatric patients without a known predisposing risk factor poses a diagnostic dilemma due to its non-specific clinical symptoms. This can lead to delayed initiation of appropriate antibiotics and surgical interventions to achieve a favorable outcome and prevent mortality. Appropriate imaging with good clinical judgment is required in the management of this infection. Outpatient surveillance for subacute and chronic complications is required for a good long-term prognosis. Few reported cases of disseminated infections with aortic aneurysm exist in the literature. We report a case of a child without predisposing risk factors managed for community-acquired MRSA sepsis, acute respiratory distress syndrome (ARDS), multiple abscesses, osteomyelitis, and necrotizing pneumonia with a post-discharge unruptured aortic aneurysm. This case emphasizes the importance of post-discharge monitoring even in patients with favorable outcomes.

Genitourinary skin and soft tissue infections: a prospective contemporary evaluation of causative pathogens.

PURPOSE: Prior literature identified anaerobes as the predominant causative organisms in genitourinary skin and soft tissue infections. However, the increasing prevalence of community acquired, methicillin resistant Staphylococcus aureus infection has brought about the growing need to reevaluate these infections and their causative organisms. We examined the causative organisms and risk factors in suppurative superficial genitourinary infections, and evaluated the growing role of community acquired, methicillin resistant S. aureus. MATERIALS AND METHODS: We performed a single institution, prospective assessment of 60 adults who presented between August 2008 and July 2010 with genitourinary skin and soft tissue infections requiring incision and drainage. Patients completed a standardized, nonvalidated questionnaire before undergoing débridement of the site. RESULTS: A total of 60 patient specimens were obtained and 92 bacterial pathogens were isolated. Of these pathogens 55% were aerobes. S. aureus was the most predominant cultured organism, representing 25% of all cultured organisms, and 65% of these isolates were community acquired, methicillin resistant S. aureus. The most commonly associated comorbidities included diabetes mellitus, tobacco smoking and heavy alcohol use. HIV/AIDS showed a statistically significant association with community acquired, methicillin resistant S. aureus infection (OR 11.00, 95% CI 1.05-115.51, p = 0.0456), as did the cumulative number of community acquired, methicillin resistant S. aureus risk factors (OR 2.64, 95% CI 1.31-5.33, p = 0.007). CONCLUSIONS: Aerobic organisms now account for most of these infections and community acquired, methicillin resistant S. aureus has emerged as a significant causative organism. Populations that may be at increased risk for these infections include patients with diabetes mellitus, heavy alcohol users and tobacco smokers. In patients with HIV/AIDS or multiple community acquired, methicillin resistant S. aureus risk factors the latter organism is more likely to be the causative organism.

Characterisation of Methicillin-Resistant Staphylococcus aureus from Alexandria, Egypt.

The present study aims to characterise clinical MRSA isolates from a tertiary care centre in Egypt's second-largest city, Alexandria. Thirty isolates collected in 2020 were genotypically characterised by microarray to detect their resistance and virulence genes and assign them to clonal complexes (CC) and strains. Isolates belonged to 11 different CCs and 14 different strains. CC15-MRSA-[V+fus] (n = 6), CC1-MRSA-[V+fus+tir+ccrA/B-1] (PVL+) (n = 5) as well as CC1-MRSA-[V+fus+tir+ccrA/B-1] and CC1153-MRSA-[V+fus] (PVL+) (both with n = 3) were the most common strains. Most isolates (83%) harboured variant or composite SCCmec V or VI elements that included the fusidic acid resistance gene fusC. The SCCmec [V+fus+tir+ccrA/B-1] element of one of the CC1 isolates was sequenced, revealing a presence not only of fusC but also of blaZ, aacA-aphD and other resistance genes. PVL genes were also common (40%). The hospital-acquired MRSA CC239-III strain was only found twice. A comparison to data from a study on strains collected in 2015 (Montelongo et al., 2022) showed an increase in fusC and PVL carriage and a decreasing prevalence of the CC239 strain. These observations indicate a diffusion of community-acquired strains into hospital settings. The beta-lactam use in hospitals and the widespread fusidic acid consumption in the community might pose a selective pressure that favours MRSA strains with composite SCCmec elements comprising mecA and fusC. This is an unsettling trend, but more MRSA typing data from Egypt are required.

Community-acquired and healthcare-associated Staphylococcus aureus infections in a pediatric hospital in southern Brazil over 8 years: how common is MRSA?

Backgrounds: Both healthcare-associated and community-acquired methicillin-resistant Staphylococcus aureus (MRSA) infections are relevant in children. The objective of our study was to evaluate their impact in a pediatric hospital in southern Brazil. Methods: Data from patients under 18 years of age with S. aureus infections between January 2013 and December 2020 were retrospectively analyzed. Data were collected regarding infection site, infection type (community-acquired or healthcare-associated), susceptibility to oxacillin [methicillin-susceptible S. aureus (MSSA) or MRSA] and other antimicrobials. We analyzed the evolution of the susceptibility rates for the isolates over this period. Results: A total of 563 patients were included, among whom the prevalences of community- and hospital-acquired MRSA infections were 46.1% and 8.1%, respectively. No significant change occurred in these prevalences over the study period. In community-acquired infections, MSSA was significantly more associated with osteoarticular infections and MRSA was more associated with respiratory and intra-abdominal infections. In healthcare-associated infections, there was an association between MSSA and primary bloodstream infections and between MRSA, skin/soft tissue infections, and respiratory infections. Community-acquired MRSA were highly susceptible to trimethoprim-sulfamethoxazole (96.1%), clindamycin (88.4%), and doxycycline (99.0%). Conclusion: Our study draws attention to the high rates of MRSA in community-acquired staphylococcal infections in this population, indicating a need to review initial protocols for severe staphylococcal infections according to local epidemiology.

Trends and risk factors in the antibiotic management of skin and soft tissue infections in the United States.

OBJECTIVE: The aim of this study was to examine the trends and risk factors of antibiotic treatment for skin and soft tissue infections (SSTIs), in the United States. METHODS: We conducted a retrospective analysis of SSTIs visits utilizing the 2011-2016 National Ambulatory Medical Care Survey. RESULTS: There were over 43 million visits for SSTIs in the US. We found no association between antibiotic treatment and gender, age, race, insurance, region, and metropolitan statistical area. Methicillin-resistant Staphylococcus aureus (MRSA) antibiotics were prescribed at 34.8% of SSTI visits, methicillin-sensitive Staphylococcus aureus (MSSA) antibiotics at 27.5%, and other antibiotics at 21.7%. Among visits treated with an antibiotic, 40.4% (n = 378) received an antibiotic with MSSA coverage, while 59.6% (n = 558) received an antibiotic with MRSA coverage. Region where the visit occurred was associated with the use of MSSA versus MRSA antibiotics (p = .013). Mean age of visits receiving MSSA antibiotics was significantly older than visits receiving MRSA antibiotics, 53.8 ± 1.2 vs. 50.9 ± 0.9 (p = .045). CONCLUSIONS: This study found that providers more frequently utilize antibiotics with MRSA coverage for SSTIs. Antibiotic class chosen was associated with region, with MRSA coverage antibiotics more likely to be prescribed in the South. Additionally, individuals receiving antibiotics with MSSA coverage were older than those receiving antibiotics with MRSA coverage.

A fusidic acid-resistant (PVL+) clone is associated with the increase in methicillin-resistant Staphylococcus aureus in New Caledonia.

OBJECTIVES: Since 2014, Staphylococcus aureus methicillin resistance has been rapidly increasing in New Caledonia and is associated with potential serious clinical repercussions. In the present study, we investigated the epidemiology of methicillin-resistant S. aureus (MRSA) in New Caledonia and the possible emergence of a particular clonal strain. METHODS: An overview of the distribution of MRSA in New Caledonia in 2019 is presented. We collected and analysed 171 clinical MRSA isolates from New Caledonia medical laboratories during August and September 2019. Among this collection, 49 representative isolates were analyzed by the French National Reference Center for Staphylococci using the StaphyType DNA microarray, allowing genetic characterization of the isolates. RESULTS: Among the 1144 S. aureus isolated over the year 2019, 442 isolates (39%) were resistant to methicillin, and 62% of these isolates were resistant to fusidic acid (FA). During the inclusion period, FA resistance rate was similar (60%). Genetic characterization evidenced CC6 as the predominant clonal complex (70%) with 26 isolates (53%) identified as CC6-MRSA-[IV+fus] (PVL+). CONCLUSIONS: These findings demonstrated a low diversity of MRSA in New Caledonia, with the dominance of a clonal complex not reported previously. The frequent fusidic acid (FA) resistance in MRSA was associated with a high prevalence of fusC gene, suggesting that FA misuse contributed to driving the selection of this clone. Our findings suggest the recommendation to stop the topical use of FA to control the emergence of this severe MRSA clone and decrease the rate of MRSA in New Caledonia.

Discordance of vancomycin minimum inhibitory concentration for methicillin-resistant Staphylococcus aureus at 2 µg/mL between Vitek II, E-test, and Broth Microdilution.

BACKGROUND: Vancomycin, the first line antibiotic for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia, is often administered inappropriately when MIC is greater than 2 µg/mL, including 'susceptible' strains. This study assessed the discordance of vancomycin minimum inhibitory concentration (MIC) for methicillin-resistant Staphylococcus aureus (MRSA). METHODS: In total, 229 MRSA isolates from blood cultures collected between 2009 and 2015 at a tertiary hospital in Taiwan were examined. The MICs of vancomycin were measured using Vitek 2, E-test, and standard broth microdilution at the level of 2 µg/mL. RESULTS: The geometric mean of the MICs of hospital-acquired MRSA was higher than that of community-acquired MRSA (P < 0.001), with the exact agreement rates (with broth microdilution) at 2 µg/mL being 53.6% in Vitek 2 and 86.7% in E-test. Overall, E-test (98.1%) had more categorical accordance than did Vitek 2 (94.0%; P = 0.026). Vitek 2 had a tendency to overestimate MRSA in high-MIC isolates, whereas E-test inclined underestimation in low-MIC isolates. Surprisingly, the discordance rates of MRSA vancomycin MICs were higher in hospital-acquired isolates (13.3%-17.0%) than in community-acquired isolates (6.2%-7.0%). CONCLUSION: The Infectious Diseases Society of America recommends the use of alternative antimicrobial agents when vancomycin MIC is ≥ 2 µg/mL; in this study, only 53.6% of the isolates tested using Vitek 2 showed a high MIC in the broth microdilution method. Accurate identification of the resistance profile is a key component of antimicrobial stewardship programs. Therefore, to reduce inappropriate antibiotic use and mitigate the emergence of resistant strains, we recommend using complementary tests such as E-test or Broth microdilution to verify the MIC before administering second-line antibiotics. STRENGTHS: (1) We compared the categorical agreement between different methods measuring MRSA MICs level. (2) Physicians should incorporate this information and consider a complementary test to verify the appropriateness of the decision of shifting vancomycin to second-line antibiotic treatment to improve patients' prognosis. (3) MRSA-vancomycin MICs at a cutoff of 2 µg/mL obtained using Vitek II exhibited a higher sensitivity level and negative predictive value than those obtained using E-test in the prediction of categorical agreement with standard broth microdilution. LIMITATION: (1) Our research was based on a single hospital-based study. (2) The MRSA strains in this study were stored for more than 12 months after isolation. (3) We did not collect information on clinical prognosis.

Understanding the Fight Against Resistance: Hospital-Acquired Methicillin-Resistant Staphylococcus Aureus vs. Community-Acquired Methicillin-Resistant Staphylococcus Aureus.

Since the identification of Staphylococcus (S.) aureus, penicillin was exclusively used to combat its disastrous toxic effects. Shortly thereafter, resistant strains arose, which were no longer susceptible to penicillin or methicillin treatments. These strands were later identified as methicillin-resistant Staphylococcus aureus (MRSA). Two particular MRSA strands that are discussed below are the hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) strands and the community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) strands. Despite arising from a single bacterium, S. aureus, each of these two strands possesses quite different resistance and virulence factors. These differences contribute to the type of population in which they affect, their ability to resist traditional treatment approaches, and their overall morbidity and mortality rates. We explore these differences by reviewing several review articles published on various reputable scientific online databases. Findings include sources from studies conducted in the United States, China, Nepal, and Uganda, ranging from 2006 to 2019. These resistance and virulence factors, the Staphylococcal cassette cartridge mecA resistance gene (SCCmec) and the Panton-Valentine Leukocidin toxin gene (PVL), were identified and isolated in each of these studies in order to appreciate similarities and differences in how they impact human beings.

Evolving Threat of Community Acquired Methicillin Resistant Staphylococcus aureus Upper Extremity Infections in the South Pacific: 2011-2015.

Background: Community Acquired Methicillin Resistant Staphylococcus aureus (CA-MRSA) rates have been increasing worldwide and contribute to a growing "global health security threat" as reported by the WHO. Our group previously reported an overall rate of 7% in CA-MRSA upper extremity infections between 2004-2009 at the Auckland Regional Hand Unit. This fell below the Center for Disease Control (CDC) recommendation for empiric antimicrobial cover once local rates exceed 10-15%. We examined prevalence and characteristics of CA-MRSA upper extremity infections in our region over a subsequent 5-year period. Methods: One thousand two hundred and fifty-two patients with upper extremity infections requiring operative management between 2011 and 2015 inclusive were included in this study. Associated clinical characteristics were recorded including ethnicity, cultured organisms, antibiotic sensitivities, infection rate, and treatment practice. Results: One hundred and fifty (12%) of patients had culture positive CA-MRSA upper extremity infections. There was an increasing annual trend. Of note, rates of CA-MRSA in the Maori and Pacific Island ethnic subpopulations exceeded 15% in 2014 and 2015. Susceptibilities, associated factors and patient demographics are reported. Conclusions: Our unit enjoys significantly lower rates of CA-MRSA upper extremity infections than has been reported internationally. However, trends are increasing relative to our prior 6-year report, and the threshold for empiric treatment has been met within the Maori and Pacific Island ethnic subpopulations. This evolving threat is also highlighted by increasing cases of multi-drug resistant CA-MRSA. Evolving regional guidelines for empiric coverage of CA-MRSA among high-risk ethnic subpopulations identified by this study are underway.

Update on bacterial pathogens: virulence and resistance.

The present article is an update of the literature on bacterial pathogens. Recognizing the interest and scientific and public health importance of infections produced by bacterial pathogens with new virulence mechanisms and/or new mechanisms of resistance to antimicrobial agents, a multidisciplinary group of Spanish physicians and microbiologists organized a joint session and revised the most important papers produced in the field during 2006. Each article was analyzed and discussed by one of the members of the panel. This paper focus on a variety of diseases that pose major clinical and public health challenges today; and include infections produced by community-acquired methicillin-resistant Staphylococcus aureus and S. aureus small colony variants, infections produced by multiply resistant coagulase-negative staphylococci, pneumococcal infections, human listeriosis, meningococcal disease, Haemophilus influenzae, pertussis, Escherichia coli, ESBL-producing organisms, and infections due to non-fermenters. After a review of the state of the art, papers selected in this field are discussed.

El presente artículo recoge una actualización bibliográfica de patógenos bacterianos. Dado el interés científico y la importancia que tienen para la salud pública las infecciones producidas por patógenos bacterianos con nuevos mecanismos de virulencia y/o nuevos mecanismos de resistencia a los antimicrobianos, un grupo multidisciplinario de microbiólogos y clínicos españoles, con experiencia en enfermedades infecciosas, organizó una reunión en la que se revisaron los artículos más importantes en este campo, publicados en 2006.El contenido de cada uno de los artículos seleccionados fue expuesto y discutido por uno de los miembros del grupo. Este artículo revisa algunas de las enfermedades infecciosas bacterianas que suponen hoy en día algunos de los principales retos para la salud pública e incluye las infecciones producidas por Staphylococcus aureus resistente a meticilina de adquisición comunitaria, las producidas por variantes de colonia pequeña de S. aureus, las relacionadas con estafilococos coagulasa negativa multirresistentes, la infección neumocócica, la listeriosis humana, la infección meningocócica, la tos ferina, las infecciones por Haemophilus influenzae, la diseminación de las bacterias productoras de BLEE, y las infecciones por bacilos gramnegativos no fermentadores. Tras la revisión de la situación actual, se discuten y comentan diferentes artículos relacionados con estos aspectos.

Community-acquired Pneumonia with Methicillin-resistant Staphylococcus Aureus in a Patient Admitted to the Intensive Care Unit: A Therapeutic Challenge.

Methicillin-resistant Staphylococcus aureus (MRSA) was previously considered a purely nosocomial pathogen. However, community-acquired MRSA has recently emerged as an important cause of severe necrotizing community-acquired pneumonia (CA-MRSA) in previously healthy individuals. This new pathogen exhibits antibiotic resistance and is linked to extended hospital stay and higher mortality. CA-MRSA has presented new therapeutic challenges due to high vancomycin treatment failure and lack of specificity of clinical findings. There is emerging evidence that treatment with linezolid leads to better patient outcomes in patients with CA-MRSA. Through this case, we aim to raise awareness about early institution of therapy for CA-MRSA whenever it is suspected, to improve patient outcomes.

Polymerase chain reaction-based open reading frame typing (POT) method analysis for a methicillin-resistant Staphylococcus aureus (MRSA) outbreak through breast-feeding in the neonatal intensive care unit.

INTRODUCTION: The route of methicillin-resistant Staphylococcus aureus (MRSA) transmission in the neonatal intensive care unit (NICU) is not clearly explained. We investigate an MRSA outbreak involving five babies in the NICU. The molecular investigation using polymerase chain reaction-based open reading frame typing (POT) method was performed. PRESENTATION OF OUTBREAK: A MRSA outbreak occurred in a six-bed NICU affecting 5 babies. Within 13 days of the emergence of index case, all five babies including triplets and other two babies were found to colonize MRSA by the active surveillance culture. Environmental surveillance cultures revealed that the preserved breast milk provided by the triplets' mother was the only item in the NICU that was positive for MRSA. The mother had a bite wound on the nipples, and the breast milk was not pasteurized. The POT method revealed that MRSA strains detected from the triplets, the breast milk, and the other baby who was fed the triplets' mother's milk were genetically identical (POT index: 106-247-33). The all strains of MRSA carried Staphylococcal cassette chromosome mec (SCCmec) IV and had good susceptibility for the non-ß-lactam antimicrobial agents, suggesting the strains were community-acquired MRSA. CONCLUSIONS: The mother's milk contaminated with community-origin MRSA is serving as the reservoir of MRSA and one of the sources of MRSA outbreaks in the NICU. It is important to closely monitor the condition of the mothers of the children in the NICU. Pasteurization of breast milk should be considered when the skin on the nipple is broken.

A nosocomial outbreak of community-associated methicillin-resistant Staphylococcus aureus among healthy newborns and postpartum mothers.

BACKGROUND: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has increasingly been isolated from individuals with no predisposing risk factors; however, such strains have rarely been linked to outbreaks in the hospital setting. The present study describes the investigation of an outbreak of CA-MRSA that occurred in the maternal-newborn unit of a large community teaching hospital in Toronto, Ontario. METHODS: Screening and clinical specimens collected from mothers and newborns delivered during the outbreak period, as well as from staff on the affected unit, were submitted for microbiological testing. Computerized delivery logs and nursing notes were reviewed, and a case control study was conducted. RESULTS: Analysis by pulsed-field gel electrophoresis revealed 38 babies and seven mothers with MRSA colonization and/or infection by the same unique strain (Canadian MRSA-10-related) from September to December 2004. Isolates were characterized as having the staphylococcal chromosome cassette mec type IVa and were positive for the Panton-Valentine leukocidin gene. No one health care worker was associated with all cases; however, mothers and newborns exposed to one particular nurse (Nurse A) were almost 23 times (odds ratio 22.7, 95% CI 3.3 to 195.9) more likely to acquire MRSA than those with no such contact. MRSA was successfully isolated from Nurse A and from an environmental swab of a telephone recently used by Nurse A; both isolates matched the pulsed-field gel electrophoresis pattern of the outbreak strain. CONCLUSION: The first nosocomial outbreak of CA-MRSA among healthy newborns and postpartum mothers in Canada is described. Effective control of sustained MRSA transmission within an institution may require prompt identification, treatment and monitoring of colonized and/or infected staff.

Spa typing and identification of pvl genes of meticillin-resistant Staphylococcus aureus isolated from a Libyan hospital in Tripoli.

OBJECTIVES: The purpose of the study was to investigate the molecular characteristics of meticillin-resistant Staphylococcus aureus (MRSA) isolated from clinical sources in Tripoli, Libya. METHODS: A total of 95 MRSA strains collected at the Tripoli medical Centre were investigated by spa typing and identification of the Panton-Valentine Leukocidin (pvl) genes. RESULTS: A total of 26 spa types were characterized and distributed among nine clonal complexes; CC5 (n=32), CC80 (n=18), CC8 (n=17) and CC22 (n=12) were the most prevalent clonal complexes. In total, 34% of the isolates were positive for PVL. CONCLUSIONS: This study demonstrated the presence of CA-MRSA and pvl positive strains in hospital settings and underlines the importance of using molecular typing to investigate the epidemiology of MRSA. Preventative measures and surveillance systems are needed to control and minimize the spread of MRSA in the Libyan health care system.

Outbreaks of infection caused by community-acquired methicillin-resistant Staphylococcus aureus in a Canadian correctional facility.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) has been identified in prison settings in the United States. The present study investigated two clusters of skin and soft tissue infection caused by community-acquired (CA) MRSA in a correctional facility in southern Ontario. METHODS: Outbreak investigations were conducted by the responsible public health authority. Strain relatedness was assessed through comparison of pulsed-field gel electrophoresis and antibiograms. RESULTS: Two distinct outbreaks of CAMRSA-associated disease occurred in 2002 and 2004. Most patients presented with abscesses in the lower extremities. All isolates had identical DNA banding patterns on pulsed-field gel electrophoresis. One-half of the affected inmates resided in a cellblock with one other affected inmate. No other risk factors were identified. CONCLUSIONS: One of the first outbreaks of CAMRSA infections in a correctional facility in Canada is documented. Taken in conjunction with outbreaks elsewhere, this suggests that residence in correctional facilities may be a risk factor for CAMRSA infection.