Imported methicillin-resistant Staphylococcus aureus, Sweden

Community methicillin-resistant Staphylococcus aureus outbreaks in areas of low prevalence

BACKGROUND

Community-acquired (CA), community-onset methicillin-resistant Staphylococcus aureus (CO-MRSA) infection presents a significant public health challenge, even where MRSA rates are historically lower. Despite successes in reducing hospital-onset MRSA, CO-MRSA rates are increasing globally, with a need to understand this trend, and the potential risk factors for re-emergence.

OBJECTIVES

This review aims to explore the characteristics of outbreaks of community-acquired community-onset methicillin-resistant Staphylococcus aureus in low-prevalence areas, to understand the factors involved in its rise, and to translate this knowledge into public health policy and further research needs.

SOURCES

PubMed, EMBASE, and Google Scholar were searched using combinations of the terms 'transmission', 'acquisition', 'community-acquired', 'MRSA', 'CA-MRSA', 'low prevalence', 'genomic', 'outbreak', 'colonisation', and 'carriage'. Wherever evidence was limited, additional articles were sought specifically, via PubMed searches. Papers where materials were not available in English were excluded.

CONTENT

Challenges in defining low-prevalence areas and the significance of exposure to various risk factors for community acquisition, such as healthcare settings, travel, livestock, and environmental factors, are discussed. The importance of genomic surveillance in identifying outbreak strains and understanding the transmission dynamics is highlighted, along with the need for robust public health policies and control measures.

IMPLICATIONS

The findings emphasise the complexity of CO-MRSA transmission and the necessity of a multifaceted approach in low-prevalence areas. This includes integrated and systematic surveillance of hospital-onset-, CO-, and livestock-associated MRSA, as has been effective in some Northern European countries. The evolution of CO-MRSA underscores the need for global collaboration, routine genomic surveillance, and comprehensive antimicrobial stewardship to mitigate the rise of CO-MRSA and address the broader challenge of antimicrobial resistance. These efforts are crucial for maintaining low MRSA prevalence and managing the increasing burden of CO-MRSA in both low and higher prevalence regions.

Genomic analysis of methicillin-resistant Staphylococcus aureus clonal complex 239 isolated from Danish patients with and without an international travel history

Introduction

International travel has been a major determinant for the introduction of pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) into naïve geographic areas. MRSA clonal complex 239 (CC239) is a highly virulent clone that is predominant in Asia. The objective of this study was to determine the geographic origin of MRSA CC239 isolates recovered from Danish cases with or without a history of international travel during 2004-2016.

Materials and methods

Human MRSA isolates with spa types t030 and t037 (n = 60) were obtained from the National Reference Laboratory for Antimicrobial Resistance. For each case, the following data were collected from notification forms: sex, age, isolation year, specimen source (screening swab or clinical sample), infection type, and international travel history. All isolates were whole-genome sequenced, and a comparative genome and phylogenetic analysis was performed.

Results

The majority of isolates originated from skin and soft tissue (SST) infections and screening swabs. In 31 out of 60 cases reported international travel to different parts of the world. Fifty-four isolates belonged to CC239, including sequence type 239 (ST239) (n = 43), ST241 (n = 5), ST4377 (n = 2), ST4378 (n = 1), ST1465 (n = 1), ST343 (n = 1), and ST592 (n = 1). The majority of the CC239 MRSA isolates (40/54) belonged to well-known geographic clades, including the Asian (n = 12), Serbian (n = 11), South American (n = 2), and Turkish (n = 15). Most MRSA ST239 isolates belonging to the highly virulent Asian clade carried sasX and were recovered from individuals who had travelled to Asia, Africa and the Middle East.

Conclusion

Our data reveal multiple introductions of MRSA CC239 into Denmark through international travel, which highlights the importance of continued genomic surveillance of MRSA in persons returning from international travel to areas where MRSA is endemic.

Import of multidrug-resistant bacteria from abroad through interhospital transfers, Finland, 2010-2019

Background

While 20–80% of regular visitors to (sub)tropical regions become colonised by extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE), those hospitalised abroad often also carry other multidrug-resistant (MDR) bacteria on return; the rates are presumed to be highest for interhospital transfers.

Aim

This observational study assessed MDR bacterial colonisation among patients transferred directly from hospitals abroad to Helsinki University Hospital. We investigated predisposing factors, clinical infections and associated fatalities.

Methods

Data were derived from screening and from diagnostic samples collected between 2010 and 2019. Risk factors of colonisation were identified by multivariable analysis. Microbiologically verified symptomatic infections and infection-related mortality were recorded during post-transfer hospitalisation.

Results

Colonisation rates proved highest for transfers from Asia (69/96; 71.9%) and lowest for those within Europe (99/524; 18.9%). Of all 698 patients, 208 (29.8%) were colonised; among those, 163 (78.4%) carried ESBL-PE, 28 (13.5%) MDR Acinetobacter species, 25 (12.0%) meticillin-resistant Staphylococcus aureus, 25 (12.0%) vancomycin-resistant Enterococcus, 14 (6.7%) carbapenemase-producing Enterobacteriaceae, and 12 (5.8%) MDR Pseudomonas aeruginosa; 46 strains tested carbapenemase gene-positive. In multivariable analysis, geographical region, intensive care unit (ICU) treatment and antibiotic use abroad proved to be risk factors for colonisation. Clinical MDR infections, two of them fatal (1.0%), were recorded for 22 of 208 (10.6%) MDR carriers.

Conclusions

Colonisation by MDR bacteria was common among patients transferred from foreign hospitals. Region of hospitalisation, ICU treatment and antibiotic use were identified as predisposing factors. Within 30 days after transfer, MDR colonisation manifested as clinical infection in more than 10% of the carriers.

Identifying asymptomatic spreaders of antimicrobial-resistant pathogens in hospital settings

Antimicrobial-resistant organisms (AMROs) can colonize people without symptoms for long periods of time, during which these agents can spread unnoticed to other patients in healthcare systems. The accurate identification of asymptomatic spreaders of AMRO in hospital settings is essential for supporting the design of interventions against healthcare-associated infections (HAIs). However, this task remains challenging because of limited observations of colonization and the complicated transmission dynamics occurring within hospitals and the broader community. Here, we study the transmission of methicillin-resistant Staphylococcus aureus (MRSA), a prevalent AMRO, in 66 Swedish hospitals and healthcare facilities with inpatients using a data-driven, agent-based model informed by deidentified real-world hospitalization records. Combining the transmission model, patient-to-patient contact networks, and sparse observations of colonization, we develop and validate an individual-level inference approach that estimates the colonization probability of individual hospitalized patients. For both model-simulated and historical outbreaks, the proposed method supports the more accurate identification of asymptomatic MRSA carriers than other traditional approaches. In addition, in silica control experiments indicate that interventions targeted to inpatients with a high-colonization probability outperform heuristic strategies informed by hospitalization history and contact tracing.

Travel-Related Antimicrobial Resistance: A Systematic Review

There is increasing evidence that human movement facilitates the global spread of resistant bacteria and antimicrobial resistance (AMR) genes. We systematically reviewed the literature on the impact of travel on the dissemination of AMR. We searched the databases Medline, EMBASE and SCOPUS from database inception until the end of June 2019. Of the 3052 titles identified, 2253 articles passed the initial screening, of which 238 met the inclusion criteria. The studies covered 30,060 drug-resistant isolates from 26 identified bacterial species. Most were enteric, accounting for 65% of the identified species and 92% of all documented isolates. High-income countries were more likely to be recipient nations for AMR originating from middle- and low-income countries. The most common origin of travellers with resistant bacteria was Asia, covering 36% of the total isolates. Beta-lactams and quinolones were the most documented drug-resistant organisms, accounting for 35% and 31% of the overall drug resistance, respectively. Medical tourism was twice as likely to be associated with multidrug-resistant organisms than general travel. International travel is a vehicle for the transmission of antimicrobial resistance globally. Health systems should identify recent travellers to ensure that adequate precautions are taken.

Antimicrobial Resistance in the Tropics

Antimicrobial resistance (AMR) is on the rise and spreading rapidly worldwide. Low- and middle-income countries, because of weak health systems, are particularly vulnerable to this increase. Population mobility further fuels the globalization of AMR, with travelers and migrants at significant risk of harboring drug-resistant organisms. This article provides an overview of the factors that contribute to the emergence, spread, and persistence of AMR, particularly antibiotic-resistance, in the tropics. Also addressed are clinical implications of this emergent global crisis for migrants and travelers, using specific scenarios commonly encountered in those populations.

Multidrug-resistant Staphylococcus aureus Colonization in Healthy Adults Is more Common in Bhutanese Refugees in Nepal than Those Resettled in Ohio

Although studies have shown that human migration is one of the risk factors for the spread of drug-resistant organisms such as methicillin-resistant Staphylococcus aureus (MRSA), surveillance studies examining MRSA among refugee populations in the US are lacking. This study aimed to assess the prevalence and molecular characteristics of S. aureus among Bhutanese refugees living in Nepal and resettled in Northeast Ohio (NEO). One hundred adult Bhutanese refugees from each geographic location were enrolled between August 2015 and January 2016. The participants were interviewed to collect demographic information and potential risk factors for carriage. Nasal and throat swabs were collected for bacterial isolation. All S. aureus isolates were characterized by spa typing and tested for the presence of Panton-Valentine leukocidin (PVL) and mecA genes; selected isolates were tested by multilocus sequence typing (MLST). The overall prevalence of S. aureus was 66.0% and 44.0% in NEO and Nepal, respectively. In Nepal, 5.8% (3/52) of isolates were MRSA and 1.1% (1/88) in NEO. Twenty-one isolates in NEO (23.9%) were multidrug-resistant S. aureus (MDRSA), while 23 (44.2%) in Nepal were MDRSA. In NEO, 41 spa types were detected from 88 S. aureus isolates. In Nepal, 32 spa types were detected from 52 S. aureus isolates. spa types t1818 and t345 were most common in NEO and Nepal, respectively. The overall prevalence of PVL-positive isolates among S. aureus in Nepal and NEO was 25.0% and 10.2%. ST5 was the most common sequence type in both locations. Bhutanese refugees living in Nepal and resettled in NEO had high prevalence of S. aureus and MDRSA. The findings suggest a potential need for CA-MRSA surveillance among the immigrant population in the U S and among people living in Nepal, and a potential need to devise appropriate public health measures to mitigate the risk imposed by community-associated strains of S. aureus and MRSA.

Inference and control of the nosocomial transmission of methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is a continued threat to human health in both community and healthcare settings. In hospitals, control efforts would benefit from accurate estimation of asymptomatic colonization and infection importation rates from the community. However, developing such estimates remains challenging due to limited observation of colonization and complicated transmission dynamics within hospitals and the community. Here, we develop an inference framework that can estimate these key quantities by combining statistical filtering techniques, an agent-based model, and real-world patient-to-patient contact networks, and use this framework to infer nosocomial transmission and infection importation over an outbreak spanning 6 years in 66 Swedish hospitals. In particular, we identify a small number of patients with disproportionately high risk of colonization. In retrospective control experiments, interventions targeted to these individuals yield a substantial improvement over heuristic strategies informed by number of contacts, length of stay and contact tracing.

High rates of meticillin-resistant Staphylococcus aureus among asylum seekers and refugees admitted to Helsinki University Hospital, 2010 to 2017

IntroductionAntimicrobial resistance is increasing rapidly in countries with low hygiene levels and poorly controlled antimicrobial use. The spread of resistant bacteria poses a threat to healthcare worldwide. Refugees and migrants from high-prevalence countries may add to a rise in multidrug-resistant (MDR) bacteria in low-prevalence countries. However, respective data are scarce.MethodsWe retrospectively collected microbiological and clinical data from asylum seekers and refugees treated at Helsinki University Hospital between January 2010 and August 2017.ResultsOf 447 asylum seekers and refugees (Iraq: 46.5%; Afghanistan: 10.3%; Syria: 9.6%, Somalia: 6.9%); 45.0% were colonised by MDR bacteria: 32.9% had extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE), 21.3% meticillin-resistant Staphylococcus aureus (MRSA), 0.7% carbapenemase-producing Enterobacteriaceae (CPE), 0.4% multiresistant Pseudomonas aeruginosa (MRPA), 0.4% multiresistant Acinetobacter baumannii (MRAB); no vancomycin-resistant Enterococcus (VRE) were found. Two or more MDR bacteria strains were recorded for 12.5% of patients. Multivariable analysis revealed geographical region and prior surgery outside Nordic countries as risk factors of MRSA colonisation. Young age (< 6 years old), short time from arrival to first sample, and prior hospitalisation outside Nordic countries were risk factors of ESBL-PE colonisation.ConclusionWe found MDR bacterial colonisation to be common among asylum seekers and refugees arriving from current conflict zones. In particular we found a high prevalence of MRSA. Refugees and migrants should, therefore, be included among risk populations requiring MDR screening and infection control measures at hospitals.

Import of community-associated, methicillin-resistant Staphylococcus aureus to Europe through skin and soft-tissue infection in intercontinental travellers, 2011-2016

OBJECTIVES

Recently, following import by travel and migration, epidemic community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has caused nosocomial outbreaks in Europe, sometimes with a fatal outcome. We describe clinico-epidemiological characteristics of CA-MRSA detected by the European Network for the Surveillance of imported S. aureus (www.staphtrav.eu) from May 2011 to November 2016.

METHODS

Sentinel surveillance at 13 travel clinics enrolling patients with travel-associated skin and soft-tissue infection (SSTI) and analysing lesion and nose swabs at one central laboratory.

RESULTS

A total of 564 independent case-patients with SSTI were enrolled and had 374 (67%) S. aureus-positive lesions, of which 14% (51/374) were MRSA. The majority of CA-MRSA isolates from SSTI were Panton-Valentine leucocidin (PVL) -positive (43/51, 84%). The risk of methicillin-resistance in imported S. aureus varied by travel region (p <0.001) and was highest in Latin America (16/57, 28%, 95% CI 17.0-41.5) and lowest in Sub-Saharan Africa (4/121, 3%, 95% CI 0.9-8.3). Major epidemic clones (USA300 / USA300 Latin-American Variant, Bengal Bay, South Pacific) accounted for more than one-third (19/51, 37%) of CA-MRSA imports. CA-MRSA SSTI in returnees was complicated (31/51 multiple lesions, 61%; 22/50 recurrences, 44%), led to health-care contact (22/51 surgical drainage, 43%; 7/50 hospitalization, 14%), was transmissible (13/47 reported similar SSTI in non-travelling contacts, 28%), and associated with S. aureus nasal colonization (28 of 51 CA-MRSA cases, 55%; 24 of 28 colonized with identical spa-type in nose and lesion, 85%).

CONCLUSIONS

Travel-associated CA-MRSA SSTI is a transmissible condition that leads to medical consultations and colonization of the infected host.

Methicillin-Resistant Staphylococcus aureus: Molecular Characterization, Evolution, and Epidemiology

Staphylococcus aureus, a major human pathogen, has a collection of virulence factors and the ability to acquire resistance to most antibiotics. This ability is further augmented by constant emergence of new clones, making S. aureus a "superbug." Clinical use of methicillin has led to the appearance of methicillin-resistant S. aureus (MRSA). The past few decades have witnessed the existence of new MRSA clones. Unlike traditional MRSA residing in hospitals, the new clones can invade community settings and infect people without predisposing risk factors. This evolution continues with the buildup of the MRSA reservoir in companion and food animals. This review focuses on imparting a better understanding of MRSA evolution and its molecular characterization and epidemiology. We first describe the origin of MRSA, with emphasis on the diverse nature of staphylococcal cassette chromosome mec (SCCmec). mecA and its new homologues (mecB, mecC, and mecD), SCCmec types (13 SCCmec types have been discovered to date), and their classification criteria are discussed. The review then describes various typing methods applied to study the molecular epidemiology and evolutionary nature of MRSA. Starting with the historical methods and continuing to the advanced whole-genome approaches, typing of collections of MRSA has shed light on the origin, spread, and evolutionary pathways of MRSA clones.

Internationally adopted children with cleft lip and/or cleft palate: Middle ear findings and hearing during childhood

OBJECTIVE

Adopted children with cleft lip and/or cleft palate form a diverse group of patients. Due to increased age at palatal repair, adopted children have a higher risk of velopharyngeal insuffiency and poor speech outcome. Delayed palate repair may also lead to longer lasting Eustachian tube dysfunction. Decreased function of the Eustachian tube causes otitis media with effusion and recurrent acute otitis media, which can lead to other middle ear problems and hearing loss.

METHODS

One-hundred-and-thirty-two adopted children treated by the Cleft palate team in Wilhelmina Children's Hospital during January 1994 and December 2014 were included. Retrospectively, middle ear findings, the need for ventilation tube insertion and hearing during childhood were assessed. Findings were compared with 132 locally born children with cleft lip and/or cleft palate.

RESULTS

Adopted children had a mean age of 26.5 months old when they arrived in our country. After the age of two the total number of otitis media with effusion episodes and the need for ventilation tube placement did not significantly differ among adopted and non-adopted children. Adopted children had significantly more tympanic membrane perforations. Hearing threshold levels normalized with increasing age. Although within normal range, adopted children showed significantly higher pure tone averages than locally born children when they were eight to ten years old.

CONCLUSION

In general, adopted patients with cleft lip and/or cleft palate did not have more middle ear problems or ventilation tubes during childhood. However, theyhave more tympanic membrane perforations.

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND

Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings.

METHODS

For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681.

FINDINGS

We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations.

INTERPRETATION

Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration.

FUNDING

UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London.

Travel and the Spread of Drug-Resistant Bacteria

PURPOSE OF REVIEW

The rise in antimicrobial resistance is an urgent public health threat which, in the absence of intervention, may result in a post-antibiotic era limiting the effectiveness of antibiotics to treat both common and serious infections. Globalization and human migration have profoundly contributed to the spread of drug-resistant bacteria. In this review, we summarize the recent literature on the importance of travelers in the spread of drug-resistant bacterial organisms. Our goal was to describe the importance of travel on a variety of clinically relevant drug-resistant bacterial organisms including extended-spectrum β-lactamase-producing Enterobacteriaceae, carbapenem-resistant Enterobacteriaceae, methicillin-resistant Staphylococcus aureus, Salmonella species, as well as other enteric infections.

RECENT FINDINGS

Travelers from high income countries, visiting low and middle income countries, frequently acquire drug-resistant bacteria, particularly extended-spectrum β-lactamase-producing Enterobacteriaceae. The highest risk is associated with travel to the Indian subcontinent. Multidrug-resistant enteric infections in travelers from Salmonella spp., Campylobacter spp., and Shigella spp. are increasing. Refugees, pilgrimages, and medical tourists are associated with considerable risk of multiple forms of drug resistance. This review highlights the importance of antimicrobial stewardship, infection control, and surveillance; particularly in low and middle income countries. International leadership with global coordination is vital in the battle against antimicrobial resistance.

Dalbavancin for outpatient parenteral antimicrobial therapy of skin and soft tissue infections in a returning traveller : Proposal for novel treatment indications

Skin and soft tissue infections (SSTIs) are among the most common health problems in travellers returning from tropical and subtropical countries. Importantly, the prevalence of Staphylococcus aureus, the most common pathogen for purulent SSTIs, with specific drug resistance, such as methicillin resistant Staphylococcus aureus (MRSA) and those expressing virulence genes, such as Panton-Valentine-leukocidin is higher in tropical regions than in most high resource settings. This poses challenges for the empirical antimicrobial treatment of SSTIs in returning travellers. This short report describes a patient with a recent travel history to Hong Kong, Singapore and the Philippines who presented with multiple mosquito bites on both upper extremities and secondary bacterial superinfection. He had previously been prescribed oral beta-lactam antimicrobial therapy but lacked adherence to this treatment. Based on the risk for MRSA infection and problems with treatment adherence to oral therapy an outpatient parenteral antimicrobial therapy with dalbavancin was administered on days 0 and 7. Microbiological culture confirmed presence of MRSA and clinical follow-up demonstrated complete remission of the SSTI within 2 weeks. Dalbavancin is a promising treatment option for empirical parenteral treatment of SSTIs in returning travellers, a population at high risk for beta-lactam resistant S. aureus skin infections.

MRSA infections in Norway: A study of the temporal evolution, 2006-2015

Background

Norway has one of the lowest prevalences of methicillin-resistant Staphylococcus aureus (MRSA) infections in the world. This study exploits the extensive data on MRSA infections in the Norwegian surveillance system to investigate the important factors defining the MRSA epidemiology.

Methods

We performed a quasi-Poisson regression of the monthly notification rate (NR) of MRSA infections reported from January 2006 to December 2015, comparing the time trend among people with an immigrant vs. Norwegian background and domestic vs. imported infections, stratified by age groups.

Findings

A total of 5289 MRSA infections were reported during the study period, of which 2255 (42·6%) were acquired in Norway, 1370 (25·9%) abroad, and 1664 (31·5%) with an unknown place of acquisition. Overall, the monthly NR increased significantly from 2006 to 2015 (+0·8% each month). The monthly increase in immigrants (+1·3%) was steeper than that in people with a Norwegian background (+0·6%). There was a significant growth (+0·4%) in the rate of domestically acquired infections, however, the NR of infections acquired abroad increased faster (+0·8%). For both imported and domestic infections, the increase occurred in persons aged < 70 years.

Interpretation

Our analysis suggests that immigration and importation, especially among persons aged < 40 years, represent important factors for the increasing notification rate of MRSA infections in Norway.

Characterization of Staphylococcus aureus from Humans and a Comparison with İsolates of Animal Origin, in North Dakota, United States

Different clones of methicillin-susceptible (MSSA) and methicillin-resistant (MRSA) Staphylococcus aureus have been found in humans as well as in animals and retail meat. However, more information about the genetic characteristics and similarities between strains is needed. The aim of this study was to identify and characterize Staphylococcus aureus from humans, and to compare their characteristics with isolates of animal origin. A total of 550 nasal swabs were taken from healthy humans, and S. aureus was isolated and identified. Positive S. aureus isolates were subjected to molecular typing and susceptibility testing. In addition, 108 MRSA isolates recovered from clinical patients in the state of North Dakota and 133 S. aureus isolates from animals and meat previously analyzed were included. The nasal carriage of S. aureus in healthy people was 7.6% and, in general, clones were genetically diverse. None of the S. aureus strains obtained from healthy people were mecA- or PVL-positive. A total of 105 (97.2%) MRSA isolates from clinical cases harbored the mecA gene and 11 (10.2%) isolated from blood stream infections harbored the PVL gene. The most common resistance profile among S. aureus from healthy people was penicillin, and from clinical cases were erythromycin-penicillin-ciprofloxacin. The rate of multidrug resistance (MDR) was 70% in humans. Most of the S. aureus harboring mecA and PVL genes were identified as ST5 and ST8, and exhibited MDR. However, S. aureus isolates of animal origin used for comparison exhibited a lower rate of MDR. The most common resistance profiles in isolates of animal origin were penicillin-tetracycline and penicillin-tetracycline-erythromycin, in animals and raw meat, respectively. The ST5 was also found in animals and meat, with ST9 and ST398 being the major clones. The genetic similarity between clones from humans and meat suggests the risk of spread of S. aureus in the food chain.

Staphylococcus aureus infections: transmission within households and the community

Staphylococcus aureus, both methicillin susceptible and resistant, are now major community-based pathogens worldwide. The basis for this is multifactorial and includes the emergence of epidemic clones with enhanced virulence, antibiotic resistance, colonization potential, or transmissibility. Household reservoirs of these unique strains are crucial to their success as community-based pathogens. Staphylococci become resident in households, either as colonizers or environmental contaminants, increasing the risk for recurrent infections. Interactions of household members with others in different households or at community sites, including schools and daycare facilities, have a critical role in the ability of these strains to become endemic. Colonization density at these sites appears to have an important role in facilitating transmission. The integration of research tools, including whole-genome sequencing (WGS), mathematical modeling, and social network analysis, has provided additional insight into the transmission dynamics of these strains. Thus far, interventions designed to reduce recurrent infections among household members have had limited success, likely due to the multiplicity of potential sources for recolonization. The development of better strategies to reduce the number of household-based infections will depend on greater insight into the different factors that contribute to the success of these uniquely successful epidemic clones of S. aureus.

Preventing the introduction of meticillin-resistant Staphylococcus aureus into hospitals

The objective of this review was to provide an up-to-date account of the interventions used to prevent the introduction of meticillin-resistant Staphylococcus aureus (MRSA) from the expanding community and livestock reservoirs into hospitals in the USA, Denmark, The Netherlands and Western Australia. A review of existing literature and local guidelines for the management of MRSA in hospitals was performed. In Denmark, The Netherlands and Western Australia, where the prevalence of MRSA is relatively low, targeted admission screening and isolation of predefined high-risk populations have been used for several decades to successfully control MRSA in the hospital. Furthermore, in Denmark and The Netherlands, all identified MRSA carriers undergo routine decolonisation, whereas only carriers of particularly transmissible or virulent MRSA clones are subjected to decolonisation in Western Australia. In the USA, which continues to be a high-prevalence MRSA country, policies vary by state and even by hospital, and whilst guidelines from professional organisations provide a framework for infection control practices, these guidelines lack the authority of a legislative mandate. In conclusion, the changing epidemiology of MRSA, exemplified by the recent emergence of MRSA in the community and in food animals, makes it increasingly difficult to accurately identify specific high-risk groups to screen for MRSA carriage. Understanding the changing epidemiology of MRSA in a local as well as global context is fundamental to prevent the introduction of MRSA into hospitals.

PCR-based identification of methicillin-resistant Staphylococcus aureus strains and their antibiotic resistance profiles

OBJECTIVE

To evaluated the PCR for mecA gene compared with the conventional oxacillin disk diffusion method for methicillin-resistant Staphylococcus aureus (S. aureus) identification.

METHODS

A total of 292 S. aureus strains were isolated from various clinical specimens obtained from hospitalized patients. Susceptibility test to several antimicrobial agents was performed by disk diffusion agar according to Clinical and Laboratory Standards Institute guidelines. The PCR amplification of the mecA gene was carried out in all the clinical isolates.

RESULTS

Among antibiotics used in our study, penicillin showed the least anti-staphylococcal activity and vancomycin was the most effective. The rate of methicillin-resistant S. aureus prevalence determined by oxacillin disk diffusion method was 47.6%; whereas, 45.1% of S. aureus isolates were mecA- positive in the PCR assay.

CONCLUSIONS

This study is suggestive that the PCR for detection of mecA gene is a fast, accurate and valuable diagnostic tool, particularly in hospitals in areas where methicillin-resistant S. aureus is endemic.

The role of international travel in the spread of methicillin-resistant Staphylococcus aureus

BACKGROUND

Increasing international travel has facilitated the transmission of various multidrug-resistant bacteria-including methicillin-resistant Staphylococcus aureus (MRSA)-across continents. Individuals may acquire MRSA from the community, healthcare facilities, or even from animal exposure. Skin contact with colonized individuals, fomites, or animals during an overseas trip may result in either asymptomatic colonization or subsequent clinically significant MRSA disease. MRSA strains that harbor the Panton-Valentine leucocidin toxin are particularly associated with community transmission and may potentially have enhanced virulence resulting in serious skin and soft tissue infections or even necrotizing pneumonia. More importantly, secondary transmission events upon return from traveling have been documented, leading to potentially detrimental outbreaks within the community or the healthcare setting. We sought to review the existing literature relating to the role of various aspects of travel in the spread of MRSA. Risk factors for acquiring MRSA during travel together with the need for targeted screening of high-risk individuals will also be explored.

METHODS

Data for this article were identified via PubMed searches using a combination of search terms: "methicillin resistance," "MRSA," "livestock-associated MRSA," "community-associated MRSA," "travel," and "outbreak." The relevant articles were extensively perused to determine secondary sources of data.

RESULTS AND CONCLUSIONS

Our review of the current literature suggests that international travel plays a significant role in the transmission of MRSA, potentially contributing to the replacement of existing endemic MRSA with fitter and more transmissible strains. Therefore, selective and targeted screening of travelers with risk factors for MRSA colonization may be beneficial. Healthcare professionals and patients should be considered for screening if they were to return from endemic areas, with the former group decolonized before returning to patient care work, in order to reduce the transmission of MRSA to vulnerable patient populations.

MRSA-colonized persons' and healthcare personnel's experiences of patient-professional interactions in and responsibilities for infection prevention in Sweden

BACKGROUND

Patient-professional interactions and adherence to infection control measures are central to the quality of care and patient safety in healthcare. Persons colonized with methicillin-resistant Staphylococcus aureus (MRSA) describe insufficient support and unprofessional behavior among healthcare personnel.

METHODS

A descriptive qualitative study was conducted to investigate managers', physicians', registered nurses' and MRSA-colonized persons' experiences of patient-professional interactions in relation to and responsibilities for infection prevention in the care of colonized patients. Five persons with MRSA colonization and 20 healthcare personnel employed within infection, hematology, nephrology or primary healthcare settings participated. The data were collected using open-ended semi-structured individual interviews with the MRSA-colonized persons and semi-structured focus group interviews with the healthcare personnel.

RESULTS

The participants perceived MRSA as an indefinable threat and described that the responsibility for infection prevention is important, but such adherence was a neglected and negotiable issue. The described actions that were acknowledged as unprofessional and inappropriate adherence to infection prevention resulted in stigmatized patients.

CONCLUSION

Colonized persons' and healthcare personnel's understanding of MRSA determines whether the personnel's behavior is perceived as proper or improper. Individual responsibility for patient-professional interactions in relation to MRSA colonization and adherence to infection control measures should be more stringent.

Community-associated methicillin-resistant Staphylococcus aureus case studies

Over the past decade, the emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has changed the landscape of S. aureus infections around the globe. Initially recognized for its ability to cause disease in young and healthy individuals without healthcare exposures as well as for its distinct genotype and phenotype, this original description no longer fully encompasses the diversity of CA-MRSA as it continues to expand its niche. Using four case studies, we highlight a wide range of the clinical presentations and challenges of CA-MRSA. Based on these cases we further explore the globally polygenetic background of CA-MRSA with a special emphasis on generally less characterized populations.

Staphylococcus aureus nasal carriage among patients and health care workers in São Tomé and Príncipe

Methicillin-resistant Staphylococcus aureus (MRSA) is a major human pathogen worldwide. However, data on MRSA prevalence in the African continent are scarce and nonexistent for São Tomé and Príncipe. In November 2010 and April 2012, a total of 332 individuals (258 patients and 74 health care workers [HCW]) from Hospital Dr. Ayres Menezes in São Tomé and Príncipe, were screened for S. aureus and MRSA carriage. Fifty-two persons (15.7%) were S. aureus nasal carriers out of which 14 (26.9%) were colonized with MRSA. MRSA isolates belonged to three clonal complexes: CC8 (PFGE type B-ST8-t064/t451-IVg/V), CC88 (PFGE E-ST88-t186/t786-IVa), and CC5 (PFGE K-ST5-t105-IVa/PFGE K-ST105-t002-II). A higher genetic diversity was found among methicillin-susceptible S. aureus (MSSA) isolates where 58.5% (n=24) belonged to four major lineages: PFGE type A-ST15-t084; PFGE C-ST508-t861 or related; PFGE D-ST152-t355 or related; and PFGE G-ST121-t159/t2304. Despite the common nonmultiresistant profile, 98% of the isolates harbored two or more virulence factors. Panton-Valentine leukocidine was detected in 36% of the isolates, all MSSA. S. aureus cross-transmission between HCW and patients in the pediatric and medicine wards and the detection of identical MRSA strains among patients in two different wards evidenced the need of implementation of additional infection control measures in this hospital.

Major West Indies MRSA clones in human beings: do they travel with their hosts?

BACKGROUND

Descriptions of the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) have seldom been produced in the Caribbean, which is a major tourism destination.

MATERIALS AND METHODS

Using DNA microarrays and spa typing, we characterized 85 MRSA isolates from human skin and soft-tissue infections from five different islands.

RESULTS

In the French West Indies (n = 72), the most frequently isolated clones were the same clones that are specifically isolated from mainland France [Lyon (n = 35) and Geraldine (n = 11) clones], whereas the clones that were most frequently isolated from the other islands (n = 13) corresponded with clones that have a worldwide endemic spread [Vienna/Hungarian/Brazilian (n = 5), Panton Valentine leukocidin-positive USA300 (n = 4), New York/Japan (n = 2), and pediatric (n = 1) clones].

CONCLUSION

The distribution of the major MRSA clones in the French (Guadeloupe and Martinique) and non-French West Indies (Jamaica, Trinidad, and Tobago) is different, and the clones most closely resemble those found in the home countries of the travelers who visit the islands most frequently. The distribution might be affected by tourist migration, which is specific to each island.

Epidemiology of MRSA in southern Sweden: strong relation to foreign country of origin, health care abroad and foreign travel

All notified MRSA cases in Skåne County have been followed since 2000. We have investigated the MRSA epidemiology over time, method of acquisition, whether some spa types are more prone to spread, and/or cause more infections, and the connection between spa type and country of acquisition/origin. All cases between 2000 and 2010 were included. Infection or colonization and the presence of PVL genes were noted. The spa types of the index cases were correlated with community or healthcare acquisition, proportion of MRSA-positive household contacts, country of origin of families and country of acquisition of MRSA. The number of cases increased from 31 in 2000 to 315 in 2010. Most cases were community-acquired and the median age was 30 years. Thirty-two per cent of the MRSA cases were found because of a clinical infection. Of the household contacts 35 % were MRSA-positive. Only 24 % of the MRSA cases were both of Swedish origin and had contracted MRSA in Sweden. An association between spa type and certain regions of acquisition/origin was noted. Spa types t044, t002 and t008 were the most predominant strains. PVL-positive spa types t008, t019 and t044 caused more skin infections than the other spa types. Our results support screening for MRSA in patients with health care contacts abroad, culturing of patients with skin infections contracted outside Sweden and performing contact tracing among household members. Knowledge of spa type might give guidance in the process of contact tracing. Eradication treatment of MRSA spa types causing more skin infections may be warranted.

First imported case of skin infection caused by PVL-positive ST30 community-associated methicillin-resistant Staphylococcus aureus clone in a returning Korean traveler from the Philippines

Although pandemic community-associated (CA-) methicillin-resistant Staphylococcus aureus (MRSA) ST30 clone has successfully spread into many Asian countries, there has been no case in Korea. We report the first imported case of infection caused by this clone in a Korean traveler returning from the Philippines. A previously healthy 30-yr-old Korean woman developed a buttock carbuncle while traveling in the Philippines. After coming back to Korea, oral cephalosporin was given by a primary physician without any improvement. Abscess was drained and MRSA strain isolated from her carbuncle was molecularly characterized and it was confirmed as ST30-MRSA-IV. She was successfully treated with vancomycin and surgery. Frequent international travel and migration have increased the risk of international spread of CA-MRSA clones. The efforts to understand the changing epidemiology of CA-MRSA should be continued, and we should raise suspicion of CA-MRSA infection in travelers with skin infections returning from CA-MRSA-endemic countries.

Medical services of a multicultural summer camp event: experiences from the 22nd World Scout Jamboree, Sweden 2011

Background

Prevention and treatment of medical issues are the main task of a health service at a youth camp. However, only few reports about organisation and implementation of camp health care are available. This makes it difficult for future camp directors to plan and estimate the health care needed for a certain camp size. We summarize the experience in planning and running health care for the 22nd World Scout Jamboree (WSJ) 2011 in Sweden.

Methods

During the WSJ, 40,061 participants from 146 nations were gathered in southern Sweden to a 12 day summer camp. Another 31,645 people were visitors. Members for the medical service were 153 volunteering medical professionals with different language and cultural backgrounds from 18 different countries.

Results

Of 40,061 participants 2,893 (7.3%) needed medical assistance. We found an equal distribution of cases to approximately one third surgical, one third medical and one third unspecified cases. Much energy was spent on health prevention, hygiene measures and organizing of psychological support.

Conclusions

A youth camp with a multicultural population and a size of a small city demands flexible staff with high communication skills. Special attention should be paid in prevention of contagious diseases and taking care of psychological issues.

Population dynamics among methicillin-resistant Staphylococcus aureus isolates in Germany during a 6-year period

Methicillin-resistant Staphylococcus aureus (MRSA) originated from the health care setting but is now emerging in communities without health care contact (CA-MRSA) or in livestock (LA-MRSA). The impact on the whole MRSA population was assessed in a German prospective multicenter study. Thirty-three laboratories consecutively collected up to 50 MRSA isolates from infection or carriage during two sampling periods in 2004 to 2005 and 2010 to 2011. Patient-related data were collected using a standardized questionnaire. Methicillin resistance was confirmed by the detection of mecA or its homologue mecA(LGA251). The spa type and major virulence factors were analyzed for each isolate. In total, 1,604 (2004 to 2005) and 1,603 (2010 to 2011) MRSA isolates were analyzed; one isolate from each sampling period harbored mecA(LGA251). LA-MRSA increased significantly (odds ratio [OR] = 22.67, 95% confidence interval [CI] = 8.51 to 85.49, P < 0.0005) and spread over Germany, originating from northwestern regions. Panton-Valentine leukocidin-positive CA-MRSA rose significantly, particularly in southern Germany, but the proportion in 2010 to 2011 remained low (2.7%, OR = 2.80, 95% CI = 1.54 to 5.34, P < 0.0005). The emerging MRSA clones changed the MRSA population in Germany during a 6-year period significantly. The ongoing epidemiological shift and changes of MRSA sources create a need for revision of guidelines for MRSA infection control and treatment.

Prevalence of antibiotic-resistant bacteria in residents of nursing homes in a Swedish municipality: healthcare staff knowledge of and adherence to principles of basic infection prevention

BACKGROUND

The aims of this study were to investigate the prevalence of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE) and extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae in residents living in Swedish nursing homes, and if carriage of resistant bacteria was related to antibiotic treatment, other risk factors, and/or staff's adherence to guidelines for infection control.

METHODS

Five hundred and sixty residents from 9 nursing homes on a total of 67 wards participated in the study and had microbiological cultures taken. Faecal samples were obtained from 495 residents (88.3%). ESBL-positive residents were followed for 2 y with repeated sampling. Two hundred and ninety-six [corrected] staff members were interviewed and observed regarding familiarity with and adherence to infection control guidelines.

RESULTS

No resident was positive for MRSA or VRE. Fifteen of the residents were found to be ESBL-positive. Residents living on wards where ESBL-positive residents were identified had been treated more frequently with antibiotics (42%), compared to those on wards where no residents with ESBL were found (28%; p = 0.02). ESBL-positive Escherichia coli isolates from residents living in adjacent rooms were found to be closely genetically related when analysed by pulsed-field gel electrophoresis, indicating transmission between residents. Staff adherence to infection control guidelines sometimes revealed shortcomings, but no significant differences regarding compliance to the guidelines could be found.

CONCLUSION

Carriage of resistant bacteria was uncommon and only ESBL-producing Enterobacteriaceae were identified in Swedish nursing homes. Usage of antibiotics was higher on wards where ESBL-positive residents were detected and there was an indication of transmission of ESBL between residents.

Bactericidal Activity of Methanol Extracts of Crabapple Mangrove Tree (Sonneratia caseolaris Linn.) Against Multi-Drug Resistant Pathogens

The crabapple mangrove tree, Sonneratia caseolaris Linn. (Family: Sonneratiaceae), is one of the foreshore plants found in estuarine and tidal creek areas and mangrove forests. Bark and fruit extracts from this plant have previously been shown to have an anti-oxidative or cytotoxic effect, whereas flower extracts of this plant exhibited an antimicrobial activity against some bacteria. According to the traditional folklore, it is medicinally used as an astringent and antiseptic. Hence, this investigation was carried out on the extract of the leaves, pneumatophore and different parts of the flower or fruit (stamen, calyx, meat of fruit, persistent calyx of fruit and seeds) for antibacterial activity using the broth microdilution method. The antibacterial activity was evaluated against five antibiotic-sensitive species (three Gram-positive and two Gram-negative bacteria) and six drug-resistant species (Gram-positive i.e. Methicillin-resistant Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium and Gram-negative i.e. Extended-spectrum beta-lactamase-Escherichia coli, multidrug-resistant-Pseudomonas aeruginosa and Acenetobacter baumannii). The methanol extracts from all tested parts of the crabapple mangrove tree exhibited antibacterial activity against both Gram-positive and Gram-negative bacteria, but was mainly a bactericidal against the Gram-negative bacteria, including the multidrug-resistant strains, when compared with only bacteriostatic on the Gram-positive bacteria. Using Soxhlet apparatus, the extracts obtained by sequential extraction with hexane, dichloromethane and ethyl acetate revealed no discernable antibacterial activity and only slightly, if at all, reduced the antibacterial activity of the subsequently obtained methanol extract. Therefore, the active antibacterial compounds of the crabapple mangrove tree should have a rather polar structure.

Combination Effects of the Antimicrobial Agents and Cinnamon Oil

The use of antimicrobial combination may be interesting because it can decrease doses and side effects of antimicrobial agents. The cinnamon essential oil was examined with respect to antimicrobial modifying activity. The combination effect of antimicrobial agents (doxycycline hyclate, ciprofloxacin HCl and metronidazole) and cinnamon oil was evaluated by checkerboard method to obtain a fractional inhibitory concentration (FIC) index. The effect of metronidazole+doxycycline hyclate and metronidazole+ciprofloxacin hydrochloride combinations were additive against Staphylococcus aureus. The indifference FIC index was observed only with the doxycycline hyclate+ciprofloxacin HCl combination. Combinations of cinnamon oil and all antimicrobial agents showed the additive effects against S. aureus. These results indicated that the antimicrobial activity of cinnamon oil was generally additive to all test antimicrobial agents.

Dry collection and culture methods for recovery of methicillin-susceptible and methicillin-resistant Staphylococcus aureus strains from indoor home environments

Staphylococcus aureus in home environments may serve as a reservoir for human colonization, making sampling of indoor surfaces relevant to exposure assessment. Using laboratory experiments and application to homes of asthmatic children in Barbados, we characterize microbiological methods adapted for settings with transportation delays between sampling and initiation of culture.

Meticillin-resistant Staphylococcus aureus (MRSA): global epidemiology and harmonisation of typing methods

This article reviews recent findings on the global epidemiology of healthcare-acquired/associated (HA), community-acquired/associated (CA) and livestock-associated (LA) meticillin-resistant Staphylococcus aureus (MRSA) and aims to reach a consensus regarding the harmonisation of typing methods for MRSA. MRSA rates continue to increase rapidly in many regions and there is a dynamic spread of strains across the globe. HA-MRSA is currently endemic in hospitals in most regions. CA-MRSA clones have been spreading rapidly in the community and also infiltrating healthcare in many regions worldwide. To date, LA-MRSA is only prevalent in certain high-risk groups of workers in direct contact with live animals. CA-MRSA and LA-MRSA have become a challenge for countries that have so far maintained low rates of MRSA. These evolutionary changes have resulted in MRSA continuing to be a major threat to public health. Continuous efforts to understand the changing epidemiology of S. aureus infection in humans and animals are therefore necessary, not only for appropriate antimicrobial treatment and effective infection control but also to monitor the evolution of the species. The group made several consensus decisions with regard to harmonisation of typing methods. A stratified, three-level organisation of testing laboratories was proposed: local; regional; and national. The functions of, and testing methodology used by, each laboratory were defined. The group consensus was to recommend spa and staphylococcal cassette chromosome mec (SCCmec) typing as the preferred methods. Both are informative in defining particular strain characteristics and utilise standardised nomenclatures, making them applicable globally. Effective communication between each of the different levels and between national centres was viewed as being crucial to inform and monitor the molecular epidemiology of MRSA at national and international levels.

The epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) in Germany

BACKGROUND

For decades, methicillin-resistant Staphylococcus aureus (MRSA) has been a major cause of infection in hospitals and nursing homes (health care-associated MRSA, HA-MRSA). Beginning in the late 1990s, many countries have also experienced a rising incidence of MRSA infection outside of the health care setting (community-associated MRSA, CA-MRSA). Moreover, animal reservoirs are increasingly considered to represent an important source of human MRSA acquisition. In this review article the authors describe the current epidemiological situation of MRSA in Germany.

METHODS

This review is based on pertinent articles published up to 2010 that were retrieved by a selective PubMed search, as well as on publications issued by national reference institutions up to 2010.

RESULTS

There are about 132 000 cases of MRSA in German hospitals each year. MRSA is found in about 18% to 20% of all inpatient-derived culture specimens that are positive for S. aureus. CA-MRSA is not yet endemic in Germany; important risk factors for its acquisition include travel to high-prevalence areas and household contact with persons that harbor a CA-MRSA infection. Agricultural livestock is the main animal reservoir for MRSA, which is often zoonotically transmitted from animals to human beings by direct contact. However, both CA-MRSA and MRSA from animal reservoirs can be imported into hospitals and cause nosocomial infections.

CONCLUSION

Hospitals and nursing homes were once the main reservoirs of MRSA, but new ones have now emerged outside of the healthcare setting. Efforts to prevent MRSA and limit its spread must rise to this new challenge.

Molecular epidemiology of methicillin-resistant Staphylococcus aureus in Israel: dissemination of global clones and unique features

From 2006 to 2009, 315 clinical methicillin-resistant Staphylococcus aureus (MRSA) isolates were collected from 5 hospitals across Israel. Most isolates (64%) were related to the global clones spa types t001-SCCmec-I (SCCmec-I stands for staphylococcal cassette chromosome mec type I) (n = 99; 31%), t002-SCCmec-II (n = 82; 26%), and t008-SCCmec-IV (n = 21; 7%), five of which were identified as MRSA strain USA-300. Seventeen strains unique to Israel were identified. SCCmec types IV and V were common among hospital-acquired isolates.

Country-to-country transfer of patients and the risk of multi-resistant bacterial infection

Management of patients with a history of healthcare contact in multiple countries is now a reality for many clinicians. Leisure tourism, the burgeoning industry of medical tourism, military conflict, natural disasters, and changing patterns of human migration may all contribute to this emerging epidemiological trend. Such individuals may be both vectors and victims of healthcare-associated infection with multiresistant bacteria. Current literature describes intercountry transfer of multiresistant Acinetobacter spp and Klebsiella pneumoniae (including Klebsiella pneumoniae carbapenemase- and New Delhi metallo-β-lactamase-producing strains), methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and hypervirulent Clostridium difficile. Introduction of such organisms to new locations has led to their dissemination within hospitals. Healthcare institutions should have sound infection prevention strategies to mitigate the risk of dissemination of multiresistant organisms from patients who have been admitted to hospitals in other countries. Clinicians may also need to individualize empiric prescribing patterns to reflect the risk of multiresistant organisms in these patients.

Multidrug-resistant Acinetobacter baumannii infections in three returning travelers evacuated from Algeria, Thailand, and Turkey after hospitalization in local intensive care units

We report three cases of returning travelers evacuated from Algeria, Thailand, and Turkey by aero-medical repatriation, following overseas hospitalization in local intensive care units for accidental injuries or medical problems. All three patients presented with imipenem-resistant Acinetobacter baumannii infections. One died whereas two recovered.

Molecular characterization of Staphylococcus aureus from outpatients in the Caribbean reveals the presence of pandemic clones

Staphylococcus aureus infections continue to pose a global public health problem. Frequently, this epidemic is driven by the successful spread of single S. aureus clones within a geographic region, but international travel has been recognized as a potential risk factor for S. aureus infections. To study the molecular epidemiology of S. aureus infections in the Caribbean, a major international tourist destination, we collected methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) isolates from community-onset infections in the Dominican Republic (n = 112) and Martinique (n = 143). Isolates were characterized by a combination of pulsed-field gel electrophoresis (PFGE), spa typing, and multilocus sequence typing (MLST) typing. In Martinique, MRSA infections (n = 56) were mainly caused by t304-ST8 strains (n = 44), whereas MSSA isolates were derived from genetically diverse backgrounds. Among MRSA strains (n = 22) from the Dominican Republic, ST5, ST30, and ST72 predominated, while ST30 t665-PVL+ (30/90) accounted for a substantial number of MSSA infections. Despite epidemiological differences in sample collections from both countries, a considerable number of MSSA infections (~10%) were caused by ST5 and ST398 isolates at each site. Further phylogenetic analysis suggests the presence of lineages shared by the two countries, followed by recent genetic diversification unique to each site. Our findings also imply the frequent import and exchange of international S. aureus strains in the Caribbean.

Methicillin-resistant Staphylococcus aureus: the European landscape

Pan-European surveillance of bacteraemia caused by methicillin-resistant Staphylococcus aureus (MRSA) shows it to be a problem affecting all European countries, although there is marked geographical variation in prevalence. Although the proportion of S. aureus bacteraemia due to MRSA is declining in many countries, data from the European Antimicrobial Resistance Surveillance System (EARSS) for 2008 showed that in more than one-third of countries the proportion remained >25%. In contrast to bacteraemia, community-associated MRSA infection in Europe remains relatively uncommon. However, there appears to be an increasing problem involving transmission of MRSA (particularly sequence type 398) from colonized livestock, particularly pigs, to farm workers, abattoir workers and veterinarians who are in contact with such animals. Molecular analysis of isolates of MRSA has shown that there has been spread of only a limited number of MRSA clones in Europe and that many of these clones show geographical clustering due to dissemination through regional healthcare networks. Despite our increasing understanding of the epidemiology of MRSA in Europe, MRSA infections continue to pose a significant public health challenge.