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

Antimicrobial Resistance in Qatar: Prevalence and Trends before and Amidst the COVID-19 Pandemic

Antimicrobial resistance (AMR) is a global healthcare challenge with substantial morbidity, mortality, and management costs. During the COVID-19 pandemic, there was a documented increase in antimicrobial consumption, particularly for severe and critical cases, as well as noticeable travel and social restriction measures that might influenced the spectrum of AMR. To evaluate the problem, retrospective data were collected on bacterial infections and antimicrobial susceptibility patterns in Qatar before and after the pandemic from 1 January 2019 to 31 December 2021, covering 53,183 pathogens isolated from reported infection episodes. The findings revealed a significant resistance pattern for extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-EBC), carbapenem-resistant Enterobacteriaceae (CR-EBC), and carbapenem-resistant Pseudomonas aeruginosa (CRPA), ciprofloxacin-resistant Salmonella and methicillin-resistant Staphylococcus aureus (MRSA). For correlation with social restrictions, ESBL-EBC and MRSA were positively correlated with changing patterns of international travel (ρ = 0.71 and 0.67, respectively; p < 0.05), while CRPA was moderately correlated with the number of COVID-19 hospitalized patients (ρ = 0.49; p < 0.05). CREBC and CRPA respiratory infections were associated with hospitalized patients (OR: 3.08 and 2.00, respectively; p < 0.05). The findings emphasize the challenges experienced during the COVID-19 pandemic and links to international travel, which probably will influence the local epidemiology of AMR that needs further surveillance and control strategies.

Antimicrobial Resistant Staphylococcus Species Colonization in Dogs, Their Owners, and Veterinary Staff of the Veterinary Teaching Hospital of Naples, Italy

This study aimed to identify Staphylococcus species isolated from nasal swabs of both healthy and diseased dogs, and those of human origin, obtained from nasal swabs of both owners and veterinary staff. Firstly, pet owners were requested to complete a questionnaire relating to the care and relationship with their pets, whose results mainly showed a statistically significant higher frequency of hand washing in diseased dogs' owners than in healthy dogs' owners. Canine nasal swabs were obtained from 43 diseased dogs and 28 healthy dogs, while human nasal swabs were collected from the respective dogs' owners (71 samples) and veterinary staff (34 samples). The isolation and identification of Staphylococcus spp. were followed by disk diffusion method to define the antimicrobial resistance profiles against 18 different molecules. Staphylococcus pseudintermedius was the most frequent isolated strain in both diseased (33.3%) and healthy (46.1%) dogs. Staphylococcus epidermidis was the most frequent isolated bacterium in diseased dogs' owners (66.6%), while in nasal samples of healthy dogs' owners, the same frequency of isolation (38.4%) was observed for both Staphylococcus epidermidis and Staphylococcus aureus. All the isolated strains showed good susceptibility levels to the tested antimicrobials; however, the carriage of oxacillin-resistant strains was significantly higher in diseased dogs than in healthy ones (71% and 7.7%, respectively). Only in three cases the presence of the same bacterial species with similar antimicrobial resistance profiles in dogs and their owners was detected, suggesting the potential bacterial transmission. In conclusion, this study suggests potential transmission risk of staphylococci from dogs to humans or vice versa, and highlights that the clinical relevance of Staphylococcus pseudintermedius transmission from dog to human should not be underestimated, as well as the role of Staphylococcus aureus from human to dog transmission.

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.

Genomic Epidemiology of Invasive Methicillin-Resistant Staphylococcus aureus Infections Among Hospitalized Individuals in Ontario, Canada

BACKGROUND

Prevention and control of methicillin-resistant Staphylococcus aureus (MRSA) infections remain challenging. In-depth surveillance integrating patient and isolate data can provide evidence to better inform infection control and public health practice.

METHODS

We analyzed MRSA cases diagnosed in 2010 (n = 212) and 2016 (n = 214) by hospitals in Ontario, Canada. Case-level clinical and demographic data were integrated with isolate characteristics, including antimicrobial resistance (AMR), classic genotyping, and whole-genome sequencing results.

RESULTS

Community-associated MRSA (epidemiologically defined) increased significantly from 23.6% in 2010 to 43.0% in 2016 (P < .001). The MRSA population structure changed over time, with a 1.5× increase in clonal complex (CC)8 strains and a concomitant decrease in CC5. The clonal shift was reflected in AMR patterns, with a decrease in erythromycin (86.7% to 78.4%, P = .036) and clindamycin resistance (84.3% to 47.9%, P < .001) and a >2-fold increase in fusidic acid resistance (9.0% to 22.5%, P < .001). Isolates within both CC5 and CC8 were relatively genetically diverse. We identified 6 small genomic clusters-3 potentially related to transmission in healthcare settings.

CONCLUSIONS

Community-associated MRSA is increasing among hospitalized individuals in Ontario. Clonal shifting from CC5 to CC8 has impacted AMR. We identified a relatively high genetic diversity and limited genomic clustering within these dominant CCs.

Acquisition of multidrug-resistant bacteria and colistin resistance genes in French medical students on internships abroad

BACKGROUND

Acquisition of multidrug resistant bacteria (MDR) and colistin resistance genes by international travellers has been demonstrated. Studies conducted in medical students during internships abroad are scant.

METHODS

Nasopharyngeal, rectal, and vaginal swabs samples were collected from 382 French medical students before and after travel to investigate the acquisition of MDR bacteria. The bacterial diversity in the samples was assessed by culture on selective media. We also genetically characterised the isolates of MDR bacteria including Extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E), methicillin-resistant Staphylococcus aureus (MRSA), and Carbapenemase-producing Enterobacteriacae (CPE) using the real-time polymerase chain reaction method. The samples were collected from 293 students and were investigated for mcr colistin-resistance genes using RT-PCR directly on the samples, followed by conventional PCR and sequencing.

RESULTS

A proportion of 29.3% (112/382) of the participants had acquired ESBL-E and 2.6% (10/382) had acquired CPE. The most common species and ESBL-E encoding gene were Escherichia coli (125/127 isolates, 98.4%) and bla_CTX-M-A (121/127, 95.3%), respectively. A proportion of 6.8% (20/293) of the participants had acquired mcr-1 genes, followed by mcr-3 (1/293, 0.3%) and mcr-8 (1/293, 0.3%). We found that taking part in humanitarian missions to orphanages (aRR = 2.01, p < 0.0001), being in contact with children during travel (aRR = 1.78, p = 0.006), the primary destination of travel being Vietnam (aRR = 2.15, p < 0.0001) and north India (aRR = 2.41, p = 0.001), using antibiotics during travel (aRR = 1.77, p = 0.01), and studying in 2018 (aRR = 1.55, p = 0.03) were associated with the acquisition of ESBL-E. When the primary destination of travel was Vietnam (aRR = 2.74, p < 0.0001) and the year of study was 2018 (aRR = 1.93, p < 0.002), this was associated with acquisition of colistin resistance genes.

CONCLUSION

Medical students are at a potential risk of acquiring ESBL-E, CPE and colistin resistance genes. A number of risk factors have been identified, which may be used to develop targeted preventive measures.

Prevalence of methicillin-resistant (mecA gene) and heat-resistant Staphylococcus aureus strains in pasteurized camel milk

Staphylococcus aureus is a significant opportunistic pathogen in humans, dairy cattle, and camels. The presence of antibiotic-resistant and heat-resistant bacteria in camel milk has become a potential public health issue. The phenotypic and molecular characterization of methicillin-resistant staphylococcal strains recovered from pasteurized camel milk distributed in retail markets of Saudi Arabia was assessed. A total of 100 samples were collected between March and May 2017. Out of the 20 S. aureus isolates that were recovered from the pasteurized camel milk, 10 were found to be resistant to cefoxitin (30 µg) and, thus, were designated as methicillin-resistant strains. The resistance ratio of methicillin-resistant S. aureus isolates for a different class of antibiotics was determined by performing the antimicrobial susceptibility test and was estimated to be approximately 60%. Polymerase chain reaction assay was performed to amplify the methicillin-resistant gene mecA, and furthermore, nucleotide sequencing was performed to detect and verify the presence of methicillin-resistant strains. Upon sequencing the putative S. aureus methicillin-resistant strains, we obtained 96 to 100% similarity to the penicillin-binding protein 2a gene (mecA) of the S. aureus strain CS100. Moreover, the 10 methicillin-resistant S. aureus isolates were also identified to be heat resistant and were stable at temperatures up to 85°C for 60 s, with 3 isolates being heat resistant even at 90°C for 60 or 90 s. The mean decimal reduction time (D₈₅ value) was 111 s for all the 10 isolates. No difference was observed in the profile of total protein between the 10 methicillin- and heat-resistant S. aureus isolates and the S. aureus strain ATCC 29737, which was determined by sodium dodecyl sulfate-PAGE analyses. Therefore, we could conclude that a relatively high percentage of the tested pasteurized camel milk samples were contaminated with S. aureus (20%) and methicillin- and heat-resistant S. aureus (10%).

Global geographic trends in antimicrobial resistance: the role of international travel

BACKGROUND

Rising antimicrobial resistance (AMR) is a threat to modern medicine, and increasing international mobility facilitates the spread of AMR. Infections with resistant organisms have higher morbidity and mortality, are costlier to treat, result in longer hospital stays and place a greater burden on health systems than infections caused by susceptible organisms. Here we review the role of travel in the international dissemination of AMR and consider actions at the levels of travelers, travel medicine practitioners and policymakers that would mitigate this threat.

RESULTS

Resistant pathogens do not recognize international borders; travelers to areas with high AMR prevalence are likely to be exposed to resistant bacteria and return to their home countries colonized. Medical tourists go between health facilities with drastically different rates of AMR, potentially transmitting highly resistant strains.Drug-resistant bacteria have been found in every continent; however, differences between countries in the prevalence of AMR depend on multiple factors. These include levels of antibiotic consumption (including inappropriate use), access to clean water, adequate sanitation, vaccination coverage, the availability of quality healthcare and access to high-quality medical products.

CONCLUSIONS

Travelers to areas with high levels of AMR should have vaccines up to date, be aware of ways of treating and preventing travelers' diarrhea (other than antibiotic use) and be informed on safe sexual practices. The healthcare systems of low- and middle-income countries require investment to reduce the transmission of resistant strains by improving access to clean water, sanitation facilities and vaccines. Efforts are needed to curb inappropriate antibiotic use worldwide. In addition, more surveillance is needed to understand the role of the movement of humans, livestock and food products in resistance transmission. The travel medicine community has a key role to play in advocating for the recognition of AMR as a priority on the international health agenda.

KEY POLICY RECOMMENDATIONS

AMR is a threat to modern medicine, and international travel plays a key role in the spread of highly resistant strains. It is essential that this is addressed at multiple levels. Individual travelers can reduce antibiotic consumption and the likelihood of infection. Travelers should have up-to-date vaccines and be informed on methods of preventing and treating travelers' diarrhea, other than use of antibiotics and on safe sexual practices, such as condom use. Healthcare facilities need to be aware of the travel history of patients to provide appropriate treatment to those who are at high risk of exposure and to prevent further spread. Internationally, in countries without reliable and universal access to clean water, sanitation and hygiene, investment is needed to reduce the emergence and spread of resistance and ensure the antimicrobials available are of assured quality. High-income countries must ensure their use of antimicrobials is appropriate to reduce selection for AMR. Surveillance across all countries is needed to monitor and respond to this emerging threat.

Antimicrobial Resistance in the Asia Pacific region: a meeting report

The Asia Pacific region, home to two-thirds of the world's population and ten of the least developed countries, is considered a regional hot-spot for the emergence and spread of antimicrobial resistance (AMR). Despite this, there is a dearth of high-quality regional data on the extent of AMR. Recognising the urgency to close this gap, Singapore organised a meeting to discuss the problems in the region and frame a call for action. Representatives from across the region and beyond attended the meeting on the "Antimicrobial Resistance in the Asia Pacific & its impact on Singapore" held in November 2018. This meeting report is a summary of the discussions on the challenges and progress in surveillance, drivers and levers of AMR emergence, and the promising innovations and technologies that could be used to combat the increasing threat of AMR in the region. Enhanced surveillance and research to provide improved evidence-based strategies and policies are needed. The major themes that emerged for an action plan are working towards a tailored solution for the region by harnessing the One Health approach, enhancing inter-country collaborations, and collaboratively leverage upon new emerging technologies. A regionally coordinated effort that is target-driven, sustainable and builds on a framework facilitating communication and governance will strengthen the fight against AMR in the Asia Pacific region.

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.

Genome Mining and Comparative Pathogenomic Analysis of An Endemic Methicillin-Resistant Staphylococcus Aureus (MRSA) Clone, ST612-CC8-t1257-SCCmec_IVd(2B), Isolated in South Africa

This study undertook genome mining and comparative genomics to gain genetic insights into the dominance of the methicillin-resistant Staphylococcus aureus (MRSA) endemic clone ST612-CC8-t1257-SCCmec_IVd(2B), obtained from the poultry food chain in South Africa. Functional annotation of the genome revealed a vast array of similar central metabolic, cellular and biochemical networks within the endemic clone crucial for its survival in the microbial community. In-silico analysis of the clone revealed the possession of uniform defense systems, restriction-modification system (type I and IV), accessory gene regulator (type I), arginine catabolic mobile element (type II), and type 1 clustered, regularly interspaced, short palindromic repeat (CRISPR)Cas array (N = 7 ± 1), which offer protection against exogenous attacks. The estimated pathogenic potential predicted a higher probability (average Pscore ≈ 0.927) of the clone being pathogenic to its host. The clone carried a battery of putative virulence determinants whose expression are critical for establishing infection. However, there was a slight difference in their possession of adherence factors (biofilm operon system) and toxins (hemolysins and enterotoxins). Further analysis revealed a conserved environmental tolerance and persistence mechanisms related to stress (oxidative and osmotic), heat shock, sporulation, bacteriocins, and detoxification, which enable it to withstand lethal threats and contribute to its success in diverse ecological niches. Phylogenomic analysis with close sister lineages revealed that the clone was closely related to the MRSA isolate SHV713 from Australia. The results of this bioinformatic analysis provide valuable insights into the biology of this endemic clone.

Patient care without borders: a systematic review of medical and surgical tourism

BACKGROUND

Medical tourism (MT) is an increasingly utilized modality for acquiring medical treatment for patients globally. This review assimilates the current literature regarding MT, with particular focus on the applications, ethics and economics.

METHODS

A systematic review of MEDLINE and PubMed Central databases for publications relating to MT from 2005 to 2018 yielded 43 articles for this review.

RESULTS

Patients seeking elective bariatric, cosmetic and orthopedic surgery abroad are motivated by significantly lower costs, all-inclusive vacation packages and reduced wait times. Complication rates as high as 56% include infection, poor aesthetic and functional outcome and adverse cardiovascular events. Cross-border reproductive care has steadily increased due to less restrictive policies in select countries; however, the depth of research on outcomes and quality of care is abysmal. Stem cell therapy promise treatments that are often not well researched and offer minimal evidence of efficacy, yet patients are drawn to treatment through anecdotal advertisements and a last sense of hope. Transplant surgery sought to decrease wait times carries many of the similar aforementioned risks and may contribute to the practice of organ trafficking in countries with high rates of poverty. Patients and countries alike are motivated by a plethora of factors to engage in the MT industry but may be doing so without accurate knowledge of the quality, safety or potential for economic gain. Safety is of utmost importance to prevent surgical complications and the spread of treatment-resistant bacteria.

CONCLUSIONS

MT is growing in popularity and complexity. The lack of standardization in its definition and regulation leads to difficulty in epidemiologic and economic analysis and ethical issues of informed consent and health equity. The findings of this review may be used by the stakeholders of MT, including patients and providers, to enhance informed decision-making and quality of care.

Quantifying the transmission dynamics of MRSA in the community and healthcare settings in a low-prevalence country

Methicillin-resistant Staphylococcus aureus (MRSA), traditionally associated with hospitals, is increasingly circulating in the community. This imposes, in turn, a potential burden on hospital infection control due to a more frequent hospitalization of colonized patients. We developed an individual-based model, reproducing community and healthcare settings, to understand the epidemiological drivers of MRSA and the connections between the society and the healthcare institutions. We show that in Norway, a low-prevalence country, the rise of infections is driven by an increasing inflow of cases from abroad rather than by an ongoing epidemic. We demonstrate the major role played by households in transmitting MRSA and show that the burden on hospitals from the growing community circulation is still limited thanks to aggressive infection-control protocols.

Methicillin-resistant Staphylococcus aureus (MRSA) is a primarily nosocomial pathogen that, in recent years, has increasingly spread to the general population. The rising prevalence of MRSA in the community implies more frequent introductions in healthcare settings that could jeopardize the effectiveness of infection-control procedures. To investigate the epidemiological dynamics of MRSA in a low-prevalence country, we developed an individual-based model (IBM) reproducing the population’s sociodemography, explicitly representing households, hospitals, and nursing homes. The model was calibrated to surveillance data from the Norwegian national registry (2008–2015) and to published household prevalence data. We estimated an effective reproductive number of 0.68 (95% CI 0.47–0.90), suggesting that the observed rise in MRSA infections is not due to an ongoing epidemic but driven by more frequent acquisitions abroad. As a result of MRSA importations, an almost twofold increase in the prevalence of carriage was estimated over the study period, in 2015 reaching a value of 0.37% (0.25–0.54%) in the community and 1.11% (0.79–1.59%) in hospitalized patients. Household transmission accounted for half of new MRSA acquisitions, indicating this setting as a potential target for preventive strategies. However, nosocomial acquisition was still the primary source of symptomatic disease, which reinforces the importance of hospital-based transmission control. Although our results indicate little reason for concern about MRSA transmission in low-prevalence settings in the immediate future, the increases in importation and global circulation highlight the need for coordinated initiatives to reduce the spread of antibiotic resistance worldwide.

Estimating the Attributable Disease Burden and Effects of Interhospital Patient Sharing on Clostridium difficile Infections

Objective:

To estimate the burden of Clostridium difficile infections (CDIs) due to interfacility patient sharing at regional and hospital levels.

Design:

Retrospective observational study.

Methods:

We used data from the Healthcare Cost and Utilization Project California State Inpatient Database (2005–2011) to identify 26,878,498 admissions and 532,925 patient transfers. We constructed a weighted, directed network among the hospitals by defining an edge between 2 hospitals to be the monthly average number of patients discharged from one hospital and admitted to another on the same day. We then used a network autocorrelation model to study the effect of the patient sharing network on the monthly average number of CDI cases per hospital, and we estimated the proportion of CDI cases attributable to the network.

Results:

We found that 13% (95% confidence interval [CI], 7.6%–18%) of CDI cases were due to diffusion through the patient-sharing network. The network autocorrelation parameter was estimated at 5.0 (95% CI, 3.0–6.9). An increase in the number of patients transferred into and/or an increased CDI rate at the hospitals from which those patients originated led to an increase in the number of CDIs in the receiving hospital.

Conclusions:

A minority but substantial burden of CDI infections are attributable to hospital transfers. A hospital’s infection control may thus be nontrivially influenced by its neighboring hospitals. This work adds to the growing body of evidence that intervention strategies designed to minimize HAIs should be done at the regional rather than local level.

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.

Increase in the prevalence of Panton-Valentine leukocidin and clonal shift in community-onset methicillin-resistant Staphylococcus aureus causing skin and soft-tissue infections in the Rhine-Neckar Region, Germany, 2012-2016

Methicillin-resistant Staphylococcus aureus (MRSA) remains a major challenge for patient care. Community-associated (CA)-MRSA often have a fitness and virulence advantage compared with their nosocomial counterparts. Increased mobility, travel activities and migration accelerate the intercontinental spread of virulent CA-MRSA strains. Outpatient clinics are the most important route of entry for CA-MRSA into hospitals. However, systematic data on CA-MRSA in Germany are limited. In this study, community-onset (CO)-MRSA skin and soft-tissue infection (SSTI) isolates in the Rhine-Neckar Region from 2012-2016 were characterised to gain an insight into their molecular epidemiology and to monitor potential introduction of virulent and dominant MRSA strains into our hospital. A total of 2475 patients with S. aureus SSTI were identified in the outpatient departments of our hospital, of which 94 (3.8%) were MRSA. In addition, 40.4% of the CO-MRSA harboured the virulence factor Panton-Valentine leukocidin (PVL). ST8-t008-MRSA-IVa/c (23.7%; 9/39) and ST80-t044-MRSA-IVc (15.8%; 6/38) were the predominant PVL-positive MRSA. Molecular typing and epidemiological data revealed that 42.6% (40/94) of strains could be traced back to a local origin and 44.7% (42/94) were endemic outside of Europe. Resistance to quinolones, clindamycin and macrolides was common, whilst resistance to trimethoprim/sulfamethoxazole, tetracycline, mupirocin, chlorhexidine and fusidic acid was low. No resistance to rifampicin, fosfomycin or linezolid was observed. This study provides insight into the clonal composition of CO-MRSA in the Rhine-Neckar Region. The increase of PVL-positive MRSA and the introduction of imported strains may affect the local MRSA landscape in the near future and should be monitored closely.

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.

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.

Estimating the probability of dengue virus introduction and secondary autochthonous cases in Europe

Given the speed of air travel, diseases even with a short viremia such as dengue can be easily exported to dengue naïve areas within 24 hours. We set out to estimate the risk of dengue virus introductions via travelers into Europe and number of secondary autochthonous cases as a result of the introduction. We applied mathematical modeling to estimate the number of dengue-viremic air passengers from 16 dengue-endemic countries to 27 European countries, taking into account the incidence of dengue in the exporting countries, travel volume and the probability of being viremic at the time of travel. Our models estimate a range from zero to 167 air passengers who are dengue-viremic at the time of travel from dengue endemic countries to each of the 27 receiving countries in one year. Germany receives the highest number of imported dengue-viremic air passengers followed by France and the United Kingdom. Our findings estimate 10 autochthonous secondary asymptomatic and symptomatic dengue infections, caused by the expected 124 infected travelers who arrived in Italy in 2012. The risk of onward transmission in Europe is reassuringly low, except where Aedes aegypti is present.

Morbidity from in-hospital complications is greater than treatment failure in patients with Staphylococcus aureus bacteraemia

BACKGROUND

Various studies have identified numerous factors associated with poor clinical outcomes in patients with Staphylococcus aureus bacteraemia (SAB). A new study was created to provide deeper insight into in-hospital complications and risk factors for treatment failure.

METHODS

Adult patients hospitalised with Staphylococcus aureus bacteraemia (SAB) were recruited prospectively into a multi-centre cohort. The primary outcome was treatment failure at 30 days (composite of all-cause mortality, persistent bacteraemia, or recurrent bacteraemia), and secondary measures included in-hospital complications and mortality at 6- and 12-months. Data were available for 222 patients recruited from February 2011 to December 2012.

RESULTS

Treatment failure at 30-days was recorded in 14.4% of patients (30-day mortality 9.5%). Multivariable analysis predictors of treatment failure included age > 70 years, Pitt bacteraemia score ≥ 2, CRP at onset of SAB > 250 mg/L, and persistent fevers after SAB onset; serum albumin at onset of SAB, receipt of appropriate empiric treatment, recent healthcare attendance, and performing echocardiography were protective. 6-month and 12-month mortality were 19.1% and 24.2% respectively. 45% experienced at least one in-hospital complication, including nephrotoxicity in 19.5%.

CONCLUSIONS

This study demonstrates significant improvements in 30-day outcomes in SAB in Australia. However, we have identified important areas to improve outcomes from SAB, particularly reducing renal dysfunction and in-hospital treatment-related complications.

Emergence of drug resistant bacteria at the Hajj: A systematic review

BACKGROUND

Hajj is the annual mass gathering of Muslims, and is a reservoir and potential source of bacterial transmission. The emergence of bacterial transmission, including multi-drug resistance (MDR) bacteria, during Hajj has not been systematically assessed.

METHODS

Articles in Pubmed, Scopus, and Google scholar were identified using controlled words relating to antibiotic resistance (AR) at the Hajj from January 2002 to January 2017. Eligible studies were identified by two researchers. AR patterns of bacteria were obtained for each study.

RESULTS

We included 31 publications involving pilgrims, Hajj workers or local patients attending hospitals in Mecca, Mina, and the Medina area. Most of these publications provided antibiotic susceptibility results. Ten of them used the PCR approach to identify AR genes. MRSA carriage was reported in pilgrims and food handlers at a rate of 20%. Low rates of vancomycin-resistant gram-positive bacteria were reported in pilgrims and patients. The prevalence of third-generation cephalosporin-resistant bacteria was common in the Hajj region. Across all studies, carbapenem-resistant bacteria were detected in fewer than 10% of E.coli isolates tested but up to 100% in K. pneumoniae and A. baumannii. Colistin-resistant Salmonella enterica, including mcr-1 colistin-resistant E.coli and K.pneumoniae were only detected in the pilgrim cohorts.

CONCLUSION

This study provides an overview of the prevalence of MDR bacteria at the Hajj. Pilgrims are at high risk of AR bacterial transmission and may carry and transfer these bacteria when returning to their home countries. Thus, pilgrims should be instructed by health care practitioners about hygiene practices aiming at reducing traveler's diarrhea and limited use of antibiotics during travel in order to reduce the risk of MDR bacterial transmission.

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.

Differences in prevalence of community-associated MRSA and MSSA among U.S. and non-U.S. born populations in six New York Community Health Centers

BACKGROUND

Staphylococcus aureus is the most common cause of Skin and Soft Tissue Infections (SSTIs) in the community in the United States of America. Community Health Centers (CHC) serve as primary care providers for thousands of immigrants in New York.

METHODS

As part of a research collaborative, 6 New York City-area CHCs recruited patients with SSTIs. Characterization was performed in all S. aureus isolates from wounds and nasal swabs collected from patients. Statistical analysis examined the differences in wound and nasal cultures among immigrant compared to native-born patients.

RESULTS

Wound and nasal specimens were recovered from 129 patients and tested for antibiotic susceptibility. 40 patients were immigrants from 15 different countries. Although not statistically significant, immigrants had lower rates of MRSA infections (n = 15) than did native-born participants, and immigrants showed significantly higher rates of MSSA wound cultures (n = 11) (OR = 3.5, 95% CI: 1.3, 9.7).

CONCLUSIONS

In our study, immigrants were more likely to present with SSTIs caused by MSSA than US-born patients. Immigants also reported lower frequencies of antibiotic prescription or consumption in the months prior to SSTI infection. This suggests that antibiotic resistance may vary regionally and that immigrants presenting with SSTIs may benefit from a broader range of antibiotics.

Identification of source and sink populations for the emergence and global spread of the East-Asia clone of community-associated MRSA

BACKGROUND

Our understanding of the factors influencing the emergence, dissemination and global distribution of epidemic clones of bacteria is limited. ST59 is a major epidemic clone of community-associated MRSA in East Asia, responsible for extensive morbidity and mortality, but has a much lower prevalence in other parts of the world. The geographic origin of ST59 and its international routes of dissemination are unclear and disputed in the literature.

RESULTS

To investigate the origin and spread of the ST59 clone, we obtained whole genome sequences of isolates from four continents, sampled over more than a decade, and carried out a time-scaled phylogeographic analysis. We discover that two distinct ST59 clades emerged concurrently, in East Asia and the USA, but underwent clonal expansion at different times. The East Asia clade was strongly enriched for gene determinants associated with antibiotic resistance, consistent with regional differences in antibiotic usage. Both clones spread independently to Australia and Europe, and we found evidence of the persistence of multi-drug resistance following export from East Asia. Direct transfer of strains between Taiwan and the USA was not observed in either direction, consistent with geographic niche exclusion.

CONCLUSIONS

Our results resolve a longstanding controversy regarding the origin of the ST59 clone, revealing the major global source and sink populations and routes for the spread of multi-drug resistant clones. Additionally, our findings indicate that diversification of the accessory genome of epidemic clones partly reflects region-specific patterns of antibiotic usage, which may influence bacterial fitness after transmission to different geographic locations.

Management of infections in critically ill returning travellers in the intensive care unit-I: considerations on infection control and transmission of resistance

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Person-to-person transmission is the most important means of transmission.

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Malaria remains by far the most important cause of death.

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Surveillance strategies based on epidemiological data (country visited, duration of travel, and time elapsed since return) and clinical syndromes associated with a systematic search policy are usually mandatory to limit the risk of an outbreak.

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Hospitalization in a single-bed room and isolation according to symptoms should be the rule while awaiting laboratory test results.

Depending on their destinations and activities, international travellers are at a significant risk of contracting both communicable and non-communicable diseases. On return to their home countries, such travellers may require intensive care. The emergence of severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV), and more recently Ebola haemorrhagic fever, has highlighted the risks. Other well-known communicable pathogens such as methicillin-resistant Staphylococcus aureus and carbapenemase-producing Enterobacteriaceae have been described previously. However, malaria remains by far the most important cause of death. The issues related to imported antibiotic resistance and protection from highly contagious diseases are reviewed here. Surveillance strategies based on epidemiological data (country visited, duration of travel, and time elapsed since return) and clinical syndromes, together with systematic search policies, are usually mandatory to limit the risk of an outbreak. Single-bed hospital rooms and isolation according to symptoms should be the rule while awaiting laboratory test results. Because person-to-person contact is the main route of transmission, healthcare workers should implement specific prevention strategies.

First report of a mecA-positive multidrug-resistant Staphylococcus pseudintermedius isolated from a dog in New Zealand

CASE HISTORY

A 14-year-old neutered male Sealyham terrier was referred for assessment of a persistent pyoderma. It had experienced numerous episodes of dermatitis involving pododermatitis, pyoderma and otitis over the previous 6 years.

CLINICAL FINDINGS

Superficial, focally deep and mucocutaneous pyoderma were present, with yellow mucoid exudate on both nares and the lower lips crusted with haemopurulent exudate. Epidermal collarettes were present on the dorsal and lateral trunk. There were peri-anal crusts and mild erythema was present on the concave aspect of both pinnae.

MICROBIOLOGICAL FINDINGS

Culture and microbiological testing identified Staphylococcus pseudintermedius as the infecting organism. Kirby-Bauer disc susceptibility testing revealed the isolate was resistant to numerous antimicrobials including oxacillin. PCR testing of the isolate identified the presence of the mecA gene which confers resistance to β-lactam antimicrobials. Pulsed field gel electrophoresis typing suggested the isolate was not related to the methicillin-resistant S. pseudintermedius that had been reported to be associated with canine infections in Western Australia.

DIAGNOSIS

Superficial, deep and mucus membrane pyoderma associated with a multi-drug resistant S. pseudintermedius.

CLINICAL RELEVANCE

This is the first recorded case of canine pyoderma involving methicillin-resistant multidrug-resistant S. pseudintermedius in New Zealand. Treatment of such cases is difficult because the number of effective and available antimicrobials is limited. This finding should raise the awareness of the veterinary and medical professions to the presence of such organisms in New Zealand and stimulate a discussion about possible biosecurity barriers, treatment strategies and prevention of zoonotic and nosocomial infections.

Molecular epidemiology of Methicillin-resistant Staphylococcus aureus in Africa: a systematic review

Methicillin-resistant Staphylococcus aureus (MRSA) infections are a serious global problem, with considerable impact on patients and substantial health care costs. This systematic review provides an overview on the clonal diversity of MRSA, as well as the prevalence of Panton-Valentine leukocidin (PVL)-positive MRSA in Africa. A search on the molecular characterization of MRSA in Africa was conducted by two authors using predefined terms. We screened for articles published in English and French through to October 2014 from five electronic databases. A total of 57 eligible studies were identified. Thirty-four reports from 15 countries provided adequate genotyping data. CC5 is the predominant clonal complex in the healthcare setting in Africa. The hospital-associated MRSA ST239/ST241-III [3A] was identified in nine African countries. This clone was also described with SCCmec type IV [2B] in Algeria and Nigeria, and type V [5C] in Niger. In Africa, the European ST80-IV [2B] clone was limited to Algeria, Egypt and Tunisia. The clonal types ST22-IV [2B], ST36-II [2A], and ST612-IV [2B] were only reported in South Africa. No clear distinctions were observed between MRSA responsible for hospital and community infections. The community clones ST8-IV [2B] and ST88-IV [2B] were reported both in the hospital and community settings in Angola, Cameroon, Gabon, Ghana, Madagascar, Nigeria, and São Tomé and Príncipe. The proportion of PVL-positive MRSA carriage and/or infections ranged from 0.3 to 100% in humans. A number of pandemic clones were identified in Africa. Moreover, some MRSA clones are limited to specific countries or regions. We strongly advocate for more surveillance studies on MRSA in Africa.

Molecular dynamics of Staphylococcus aureus nasal carriage in Hajj pilgrims

During the 2012 Hajj season, the risk of acquisition of Staphylococcus aureus nasal carriage in a cohort of French pilgrims was 22.8%, and was statistically associated with the acquisition of viral respiratory pathogens (p 0.03). The carriage of S. aureus belonging to the emerging clonal complex 398 significantly increased following the pilgrimage (p < 0.05).

Staphylococcus aureus dry stress survivors have a heritable fitness advantage in subsequent dry exposure

Staphylococcus aureus is a major cause of hospital-acquired infections. The ability to survive on abiotic surfaces is an important characteristic that facilitates transmission between human hosts. We found that S. aureus survivors of dry surface incubation are resistant to subsequent dry stress exposure. Survivors also had reduced sensitivity to the disinfectant chlorhexidine gluconate, but not to ethanol. By using a set of mutants in cardiolipin synthase genes, we further demonstrated that the housekeeping cardiolipin synthase, Cls2, was significant for survival on dry surface. Taken together, this study provides insights into S. aureus survival outside of a host.

Skin and soft tissue infections in intercontinental travellers and the import of multi-resistant Staphylococcus aureus to Europe

Staphylococcus aureus is emerging globally. Treatment of infections is complicated by increasing antibiotic resistance. We collected clinical data and swabs of returnees with skin and soft tissue infections (SSTI) at 13 travel-clinics in Europe (www.staphtrav.eu). Sixty-two percent (196/318) SSTI patients had S. aureus-positive lesions, of which almost two-thirds (122/196) were Panton-Valentine leukocidin (PVL) positive. PVL was associated with disease severity, including hospitalization for SSTI (OR 5.2, 95% CI 1.5-18.2). In returnees with SSTI, longer travel and more intense population contact were risk factors for nasal colonization with PVL-positive S. aureus. Imported S. aureus frequently proved resistant to trimethoprim-sulfamethoxazole (21%), erythromycin (21%), tetracycline (20%), ciprofloxacin (13%), methicillin (12%) and clindamycin (8%). Place of exposure was significantly (p < 0.05) associated with predominant resistance phenotypes and spa genotypes: Latin America (methicillin; t008/CC24/304), Africa (tetracycline, trimethoprim-sulfamethoxazole; t084/CC84, t314/singleton, t355/CC355), South Asia (trimethoprim-sulfamethoxazole, ciprofloxacin; t021/CC21/318), South-East Asia (clindamycin; t159/CC272). USA300-like isolates accounted for 30% of all methicillin-resistant S. aureus imported to Europe and were predominantly (71%) acquired in Latin America. Multi-resistance to non-β-lactams were present in 24% of imports and associated with travel to South Asia (ORcrude 5.3, 95% CI 2.4-11.8), even after adjusting for confounding by genotype (ORadjusted 3.8, 95% 1.5-9.5). Choosing randomly from compounds recommended for the empiric treatment of severe S. aureus SSTI, 15% of cases would have received ineffective antimicrobial therapy. These findings call for the development of regionally stratified guidance on the antibiotic management of severe imported S. aureus disease and put the infected and colonized traveller at the centre of interventions against the global spread of multi-resistant S. aureus.

Antibiotic Resistance Spreads Internationally Across Borders

Antibiotic-resistant (ABR) bacteria develop when bacteria are exposed to antibiotics either during treatments in humans or animals or through environmental sources contaminated with antibiotic residues. Resistant bacteria selected by medical, agricultural, and industrial use spread globally through international travel, the export of animals and retail products, and the environment. It is essential that nations work together to identify how to reduce emergence and amplification of resistant bacteria through sensible antibiotic treatment guidelines and restrictions, concerted efforts for surveillance, and infection control.

Antimicrobial resistance and molecular analysis of methicillin-resistant Staphylococcus aureus collected in a Spanish hospital

Clonal distribution of methicillin-resistant Staphylococcus aureus (MRSA) in hospitals may differ according to the geographic location and time period. Knowledge of MRSA clonal epidemiology in hospital settings involves much more than the study of healthcare-associated MRSA (HA-MRSA) clones. In recent years, investigators have documented the introduction of both community-associated MRSA (CA-MRSA) and livestock-associated MRSA (LA-MRSA) clones, the emergence of clones carrying Staphylococcal cassette chromosome mec (SCCmec) XI, and the genetic diversity among sporadic MRSA isolates. The allocation of certain antibiotypes to dominant MRSA clones in an institution allows their use as phenotypic markers for a preliminary search for new clones, early detection of clonal shift, and as a guide for better empirical therapy, infection control, and treatment within a particular institution. For these reasons, we identified 938 strains detected in a System of Universal Active Surveillance of MRSA in clinical samples during the period 2009-2010, obtaining the clonal distribution of MRSA at the Hospital Universitario de Canarias (Tenerife, Spain) and the relationship between antimicrobial susceptibility and three major clones present. The antibiotypes that best defined the ST5-MRSA-IV (Pediatric) clone showed resistance to tobramycin and susceptibility to clindamycin, erythromycin, gentamicin, rifampin, trimethoprim-sulfamethoxazole, vancomycin, quinupristin/dalfopristin, and linezolid, whereas the ST22-MRSA-IV clone (EMRSA-15) showed susceptibility to these antibiotics, and finally, the ST36-MRSA-II clone (EMRSA-16) was resistant to clindamycin, erythromycin, and tobramycin and susceptible to the remaining antimicrobials. Similar observations would allow the early detection of changes in clonal epidemiology by analysis of antimicrobial susceptibility of the isolates within a single institution.