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

Community MRSA outbreaks in areas of low prevalence

OBJECTIVES

This review aims to explore the characteristics of outbreaks of community-acquired community-onset methicillin-resistant Staphylococcus aureus (CO-MRSA) 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", "CA-MRSA" "MRSA", "community-acquired", "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

Community-acquired, community onset MRSA infection presents a significant public health challenge, even in low prevalence areas; where MRSA rates are historically lower. Despite successes in reducing hospital-onset MRSA (HO-MRSA), CO-MRSA rates are increasing globally, with a need to understand this trend, and the potential risk factors for re-emergence. 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 HO-, CO-, and livestock-associated MRSA (LA-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.

Dissemination of meticillin-resistant Staphylococcus aureus sequence type 8 (USA300) in Taiwan

BACKGROUND

In Taiwan, sequence type (ST) 239 and ST59 were two major clones among meticillin-resistant Staphylococcus aureus (MRSA) clinical isolates in the past two decades. USA300 (ST8) prevailed in the Americas but not in outside areas. Recently USA300 (ST8) emerged and was increasingly identified in Taiwan; we thus conducted an island-wide study to explore the role of USA300 among MRSA isolates.

METHODS

One hundred MRSA bloodstream isolates identified in 2020 from each of the six participating hospitals in Taiwan were collected and characterized. The first 10 ST8 isolates from each hospital were further analysed by whole-genome sequencing.

RESULTS

Of the 590 confirmed MRSA isolates, a total of 22 pulsotypes and 21 STs were identified. The strain of pulsotype AI/ST8 was the most common lineage identified, accounting for 187 isolates (31.7%) and dominating in five of six hospitals, followed by pulsotype A/ST239 (14.7%), pulsotype C/ST59 (13.9%) and pulsotype D/ST59 (9.2%). Of the 187 pulsotype AI/ST8 isolates, 184 isolates were characterized as USA300 and clustered in three major sub-pulsotypes, accounting for 78%. Ninety per cent of the 60 ST8 isolates for whole-genome sequencing were clustered in three major clades.

CONCLUSIONS

In 2020, USA300 became the most common clone of MRSA in Taiwan, accounting for >30% of MRSA bloodstream isolates island wide. Most of USA300 isolates circulating in Taiwan might have been imported on multiple occasions and evolved into at least three successful local clades. MRSA USA300 has successfully established its role in Taiwan, an area outside of the Americas.

[Genitoanal infections caused by Panton-Valentine leukocidin (PVL)-positive Staphylococcus aureus : Smear infection or sexually transmitted disease?]

Panton-Valentine leukocidin (PVL) is a pore-forming exotoxin produced by certain Staphylococcus (S.) aureus strains, which is responsible for the increased virulence of the pathogen. Thus, infections caused by PVL-positive S. aureus tend to recur. Usually, the infection is a smear infection, which can cause folliculitis and purulent lid margin inflammation in addition to the classic mucocutaneous abscesses. Recently, recurrent genitoanal infections caused by PVL-positive S. aureus have also been described. In most cases, this is a sexually transmitted disease. Currently, it is assumed that most infections are imported from abroad. In addition to treatment of these infections, decolonization should be performed for prophylaxis of recurrence.

Epidemiology of Methicillin-Resistant Staphylococcus aureus in Slovakia, 2020 - Emergence of an Epidemic USA300 Clone in Community and Hospitals

Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of health care-associated infections. Additionally, over the decades, the spread of community-associated (CA-MRSA) clones has become a serious problem. The aim of this study was to gain data on the current epidemiology of MRSA in Slovakia. Between January 2020 and March 2020, single-patient MRSA isolates (invasive and/or colonizing) were collected in Slovakia from hospitalized inpatients (16 hospitals) or outpatients (77 cities). Isolates were characterized via antimicrobial susceptibility testing, spa typing, SCCmec typing, the detection of mecA/mecC, genes coding for Panton-Valentine leukocidin (PVL), and the arcA gene (part of the arginine catabolic mobile element [ACME]). Out of 412 isolates, 167 and 245 originated from hospitalized patients and outpatients, respectively. Inpatients were most likely older (P < 0.001) and carried a strain exhibiting multiple resistance (P = 0.015). Isolates were frequently resistant to erythromycin (n = 320), clindamycin (n = 268), and ciprofloxacin/norfloxacin (n = 261). 55 isolates were resistant to oxacillin/cefoxitin only. By clonal structure, CC5-MRSA-II (n = 106; spa types t003, t014), CC22-MRSA-IV (n = 75; t032), and CC8-MRSA-IV (n = 65; t008) were the most frequent. We identified PVL in 72 isolates (17.48%; 17/412), with the majority belonging to CC8-MRSA-IV (n = 55; arcA+; t008, t622; the USA300 CA-MRSA clone) and CC5-MRSA-IV (n = 13; t311, t323). To the best of our knowledge, this is the first study on the epidemiology of MRSA in Slovakia. The presence of the epidemic HA-MRSA clones CC5-MRSA-II and CC22-MRSA-IV was found, as was, importantly, the emergence of the global epidemic USA300 CA-MRSA clone. The extensive spread of USA300 among inpatients and outpatients across the Slovakian regions warrants further investigation. IMPORTANCE The epidemiology of MRSA is characterized by the rise and fall of epidemic clones. Understanding the spread, as well as the evolution of successful MRSA clones, depends on the knowledge of global MRSA epidemiology. However, basic knowledge about MRSA epidemiology is still fragmented or completely missing in some parts of the world. This is the first study of MRSA epidemiology in Slovakia to identify the presence of the epidemic HA-MRSA clones CC5-MRSA-II and CC22-MRSA-IV and, importantly and unexpectedly, the emergence of the global epidemic USA300 CA-MRSA clone in the Slovakian community and hospitals. So far, USA300 has failed to spread in Europe, and this study documents an extensive spread of this epidemic clone in a European country for the first time.

Mandatory Notification of Panton-Valentine Leukocidin-Positive Methicillin-Resistant Staphylococcus aureus in Saxony, Germany: Analysis of Cases from the City of Leipzig in 2019

In Germany, Saxony is the only federal state where the detection of a Panton-Valentine Leukocidin (PVL)-positive Methicillin-resistant Staphylococcus aureus (MRSA) has to be notified to the local health authority (LHA). The LHA reports the case to the state health authority and introduces concrete infection control measures. We analyzed isolates from the respective cases in 2019, which were collected in local microbiological laboratories and sent to the National Reference Centre (NRC) for Staphylococci and Enterococci for strain characterization and typing. Antibiotic resistance testing was done by broth microdilution. Molecular characterization was performed using spa and SCCmec typing, MLST, and the PCR detection of marker genes associated with distinct MRSA lineages. Demographic and clinical data of the individual cases were assessed and the LHA performed epidemiological investigations. Thirty-nine (index) persons, diagnosed with a PVL-positive MRSA, were initially reported to the LHA. Most patients suffered from skin and soft-tissue infections (SSTI). For 21 of the index cases, household contacts were screened for MRSA. Seventeen out of 62 contacts were also colonized with a PVL-positive MRSA. The median age of altogether 58 individuals was 23.5 years. In over half of the cases, the home country was not Germany and/or a history of travel or migration was reported. Molecular characterization revealed the presence of various epidemic community-associated MRSA lineages, with "USA300", including the North American Epidemic (ST8-MRSA-IVa) and the South American Epidemic Clone (ST8-MRSA-IVc), the "Sri Lankan Clone" (ST5-MRSA-IVc), and the "Bengal Bay Clone" (ST772-MRSA-V) being more prevalent. In eight out of nine households, the contact persons were colonized with the same clone as the respective index case, suggesting a close epidemic and microbiological link. The obligation to report PVL-positive MRSA enables us to detect the occurrence of PVL-producing MRSA and its spread in the population as early as possible. Timely detection allows the targeted deployment of reliable anti-infective measures.

Trimethoprim-sulfamethoxazole resistance patterns among Staphylococcus aureus in the United States, 2012-2018

We reviewed trimethoprim-sulfamethoxazole antibiotic susceptibility testing data among Staphylococcus aureus using 3 national inpatient databases. In all 3 databases, we observed an increases in the percentage of methicillin-resistant Staphylococcus aureus that were not susceptible to trimethoprim-sulfamethoxazole. Providers should select antibiotic regimens based on local resistance patterns and should report changes to the public health department.

Escalation of antimicrobial resistance among MRSA part 1: focus on global spread

INTRODUCTION

Staphylococcus aureus produce numerous virulence factors that influence tissue invasion, cytotoxicity, membrane damage, and intracellular persistence allowing them to be very common human pathogens. S. aureus isolates exhibit considerable diversity though specific genotypes have been associated with antimicrobial resistance (AMR) and toxin gene profiles. MRSA is an important pathogen causing both community-acquired (CA) and healthcare-acquired (HCA) infections. Importantly, over the past several decades, both HCA-MRSA and CA-MRSA have spread all over the globe. Even more concerning is that CA-MRSA clones have disseminated into hospitals and HCA-MRSA have entered the community. Factors that enhance spread of MRSA include: poor antimicrobial stewardship and inadequate infection control. The emergence and spread of multidrug resistant (MDR) MRSA has limited therapeutic options.

AREAS COVERED

The authors discuss the escalation of MRSA, both HCA-MRSA and CA-MRSA across the globe. A literature search of MRSA was performed via PubMed (up to September 2022), using the key words: antimicrobial resistance; β-lactams; community-associated MRSA; epidemiology; infection; multidrug resistance; Staphylococcus aureus.

EXPERT OPINION

Over the past several decades, MRSA has spread all over the globe. We encourage the judicious use of antimicrobials in accordance with antimicrobial stewardship programs along with infection control measures to minimize the spread of MRSA.

Prevalence, Infectious Characteristics and Genetic Diversity of Staphylococcus aureus and Methicillin-Resistant Staphylococcus aureus (MRSA) in Two Raw-Meat Processing Establishments in Northern Greece

In the present study, we investigated the isolation frequency, the genetic diversity, and the infectious characteristics of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) from the incoming meat and the meat products, the environment, and the workers' nasal cavities, in two meat-processing establishments in northern Greece. The isolated S. aureus strains were examined for their resistance to antimicrobials, carriage of the mecA and mecC genes, carriage of genes encoding for the production of nine staphylococcal enterotoxins, carriage of the Panton-Valentine Leukocidin and Toxic Shock Syndrome genes, and the ability to form biofilm. The genetic diversity of the isolates was evaluated using Pulsed Field Gel Electrophoresis (PFGE) and spa typing. S. aureus was isolated from 13.8% of the 160 samples examined, while only one sample (0.6%) was contaminated by MRSA carrying the mecA gene. The evaluation of the antimicrobial susceptibility of the isolates revealed low antimicrobial resistance. The higher resistance frequencies were observed for penicillin (68.2%), amoxicillin/clavulanic acid (36.4%) and tetracycline (18.2%), while 31.8% of the isolates were sensitive to all antimicrobials examined. Multidrug resistance was observed in two isolates. None of the isolates carried the mecC or lukF-PV genes, and two isolates (9.1%) harbored the tst gene. Eight isolates (36.4%) carried the seb gene, one carried the sed gene, two (9.1%) carried both the sed and sei genes, and one isolate (4.5%) carried the seb, sed and sei genes. Twenty-one (95.5%) of the isolates showed moderate biofilm production ability, while only one (4.5%) was characterized as a strong biofilm producer. Genotyping of the isolates by PFGE indicates that S. aureus from different meat-processing establishments represent separate genetic populations. Ten different spa types were identified, while no common spa type isolates were detected within the two plants. Overall, our findings emphasize the need for the strict application of good hygienic practices at the plant level to control the spread of S. aureus and MRSA to the community through the end products.

Hanitsch L, Krüger R, K. Lindner A, S. Stegemann M, Nurjadi D. Skin Infections Due to Panton-Valentine Leukocidin-Producing S. Aureus

BACKGROUND

Panton-Valentine leukocidin (PVL)-producing Staphylococcus aureus (PVL-SA) strains are frequently associated with large, recurring abscesses in otherwise healthy young individuals. The typical clinical presentation and the recommended diagnostic evaluation and treatment are not widely known.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed, with special attention to international recommendations.

RESULTS

PVL-SA can cause leukocytolysis and dermatonecrosis through specific cell-wall pore formation. Unlike other types of pyoderma, such conditions caused by PVL-SA have no particular site of predilection. In Germany, the PVL gene can be detected in 61.3% (252/411) of skin and soft tissue infections with S. aureus. Skin and soft tissue infections with PVL-SA recur three times as frequently as those due to PVL-negative S. aureus. They are diagnosed by S. aureus culture from wound swabs and combined nasal/pharyngeal swabs, along with PCR for gene detection. The acute treatment of the skin abscesses consists of drainage, followed by antimicrobial therapy if needed. Important secondary preventive measures include topical cleansing with mupirocin nasal ointment and whole-body washing with chlorhexidine or octenidine. The limited evidence (level IIb) concerning PVL-SA is mainly derived from nonrandomized cohort studies and experimental analyses.

CONCLUSION

PVL-SA skin infections are easily distinguished from other skin diseases with targeted history-taking and diagnostic evaluation.

Understanding and comparing the medical tourism cancer patient with the locally managed patient: A case control study

Introduction

Medical tourism is characterized by people seeking treatment abroad for various medical conditions due to varied reasons, many of whom benefit from specialized care for non-communicable diseases. Conversely, there are associated negative effects such as medical complications and weakened health systems. Currently, there is paucity of scientific evidence on patient-related factors influencing seeking treatment benefits abroad. This study sought to compare patient-related factors associated with choice of cancer treatment center locally or abroad, to understand reasons for seeking treatment outside Kenya.

Materials and methods

As a case-control study, 254 cancer patients were randomly sampled to compare responses from those who chose to receive initial treatment abroad or in Kenya. The cases were recruited from Ministry of Health while the controls from Kenyatta National Hospital and Texas Cancer Center. Data was analyzed using SPSS Software Version 21. Descriptive statistics, bivariate and multiple logistic regression analysis was carried out. Level of significance was set at 5%.

Results

Out of 254 respondents, 174 (69.5%) were treated for cancer in Kenya and 80 (31.5%) in India. We found that cost effectiveness was a significant factor for over 73% of all respondents. The study revealed independent predictors for seeking treatment in India were: monthly income higher than US$ 250; every additional month from when disclosure to patients was done increased likelihood by 1.16 times; physician advice (Odds Ratio(OR) 66; 95% Confidence Interval(CI) 7.9–552.9); friends and family (OR 42; 95% CI 7.07–248.6); and perception of better quality of care (OR 22.5; 95% CI 2.2–230.6).

Conclusion

Reasons patients with cancer sought treatment in India are multifactorial. Several of these can be addressed to reverse out-ward bound medical tourism and contribute to improving the in-country cancer healthcare. It will require strengthening the health system accordingly and sensitizing the medical fraternity and general public on the same.

Imported Panton-valentine leucocidin (PVL)-positive Staphylococcus aureus skin infections: patients' perspective on quality of life and quality of medical care

PVL-positive S. aureus skin and soft tissue infections have a major impact on quality of life and mental health, often for months and beyond the period of infection. Pre-treating physicians were poorly informed about the PVL toxin. Increased awareness for early diagnosis and treatment of this yet neglected disease are required.

Rate of methicillin-resistant Staphylococcus aureus in pediatric emergency departments in Spain

INTRODUCTION

Staphylococcus aureus is a common germ in bacterial infections in children. The rate of methicillin-resistant S. aureus (MRSA) is increasing lately.

OBJECTIVES

The main aim is to know the rate of positive cultures to MRSA in Spanish pediatric emergency departments. The secondary aims are to analyse the risk factors for MRSA isolation (patient origin, history of hospitalization or surgery in the previous 90 days, antibiotherapy in the previous 60 days, presence of comorbidity, invasive devices, prior MRSA isolation) and to analyse the morbidity of these infections.

METHODOLOGY

Retrospective multicenter study (07/01/2017-06/30/2018) with review of patient histories with isolation of S. aureus in samples of any origin obtained in 8 pediatric emergency departments of the Infectious Diseases Working Group of the Spanish Society of pediatric Emergencies.

RESULTS

During this period, S. aureus was detected in 403 patients (average age 75.8 ± 59.2 months; 54.8% male): 28.8% hospital-related infections (HRI) and 71.2% community-related infections (CRI). Overall, MRSA rate was 16.6% (95% CI: 13-20.2%); 18.1% in HRI and 16.2% in CRI (p > 0.05). The highest rates of MRSA were obtained in skin abscesses (29.3%, CI 95%: 21.8-36.8%), patients not born in Spain (52%; CI 95%: 32-72%) or patients with a previous MRSA infection (90%; CI 95% 71.4-100%). 167 (41%) patients were admitted, 12 (3%) had complications and 4 (1%) suffered sequels. There were no deaths.

CONCLUSIONS

The overall MRSA rate was one in 6 staphylococcal infections. Higher MRSA rates were detected in samples of suppurating skin injuries and in foreign children or in children with a history of previous MRSA infection. In suppurative skin lesions, early drainage is essential and the change to an antibiotic with MRSA coverage should be considered if the evolution is inadequate.

Genomic Characterisation of CC398 MRSA Causing Severe Disease in Australia

Complex (CC) 398 livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) has been reported worldwide in a variety of food-animal species. Although CC398 is synonymous with LA-MRSA, community-associated MRSA (CA-MRSA) variants have emerged, including the Panton-Valentine leukocidin (PVL)-positive ST398-V and ST398 single locus variant ST1232-V, and the PVL-negative ST398-V clones. Using comparative genomic analysis, we determined if ten CC398 MRSA bacteraemia episodes recently identified in Australia were due to LA-MRSA or CA-MRSA CC398. The isolates were sourced from the Australian Group on Antimicrobial Resistance S. aureus surveillance program and episodes occurred across Australia Whole genome sequencing and phylogenetic comparison of the ten CC398 bacteraemia isolates with previously published CC398 MRSA whole-genome sequences identified the Australian CC398 isolates were closely related to the human-associated II-GOI clade, and the livestock-associated IIa clade. The identified CC398 MRSA clones were: PVL-positive ST1232-V (5C2&5), PVL-negative community-associated ST398-V (5C2&5) and livestock-associated ST398-V (5C2&5). Our findings demonstrate the importance of using whole genome sequencing and comparing the sequences to international sequences to distinguish between CC398 CA- and LA- MRSA and to determine the isolates' origin. Furthermore, our findings suggest CC398 CA-MRSA has become established in the Australian community and ST398-V (5C2&5) LA-MRSA is now widespread in Australian piggeries. Our study emphasizes the need of national one health antimicrobial resistance surveillance programs to assist in monitoring the ongoing epidemiology of MRSA and other clinically significant antimicrobial resistant organisms.

Current and future options for treating complicated skin and soft tissue infections: focus on fluoroquinolones and long-acting lipoglycopeptide antibiotics

Bacterial skin and soft tissue infections are among the most common bacterial infections and constitute a major burden for patients and healthcare systems. Care is complicated by the variety of potential pathogens, some with resistance to previously effective antimicrobial agents, the wide spectrum of clinical presentations and the risk of progression to life-threatening forms. More-efficient care pathways are needed that can reduce hospital admissions and length of stay, while maintaining a high quality of care and adhering to antimicrobial stewardship principles. Several agents approved recently for treating acute bacterial skin and skin structure infections have characteristics that meet these requirements. We address the clinical and pharmacological characteristics of the fourth-generation fluoroquinolone delafloxacin, and the long-acting lipoglycopeptide agents dalbavancin and oritavancin.

Lateral Flow Immunoassay for the Detection of Panton-Valentine Leukocidin in Staphylococcus aureus From Skin and Soft Tissue Infections in the United Arab Emirates

Introduction

Panton Valentine leukocidin (PVL) is a virulence factor which is associated with methicillin sensitive and resistant Staphylococcus aureus (MSSA/MRSA) causing skin and soft tissue infections (SSTI). This study aimed to evaluate a novel lateral flow immunoassay (LFI) for PVL detection in S. aureus cultures and to describe their genotypic characterization.

Methods

The study was carried out from January-August 2020 in Dubai, United Arab Emirates. S. aureus isolates associated with SSTI were tested for PVL detection using LFI. DNA microarray-based assays were used for molecular characterization including detection of pvl genes.

Results

One-hundred thirty-five patients with a clinical diagnosis of SSTIs were recruited. Sixty-six patients received antibiotics, mostly beta lactams (n=36) and topical fusidic acid (n=15). One-hundred twenty-nine isolates (MRSA: n=43; MSSA: n=86) were tested by LFI and DNA microarrays. All 76 (58.9%) isolates which were unambiguously negative for the PVL in LFI were negative for pvl genes using the DNA microarray. All the LFI PVL positive isolates (n=53) had pvl genes detected. This translates into 100% each for sensitivity, specificity, positive and negative predictive values for the LFI. The LFI typically takes about 15 min inclusive of a 10 min incubation period. Predominant S. aureus clonal complexes (CC) were CC30 (n=18), CC22 (n=13), CC5 (n=12), CC1 (n=11), CC152 (n=8), CC15 (n=7); CC97 (n=7); CC8 and CC20 (n=6 each). Among MRSA, the proportion of pvl-positives (35/43; 81%) was higher than among MSSA (n/N=18/86; 21%). The fusidic acid resistance gene fusC was detected in 14 MRSA (33%) compared to 8 MSSA (9%). A co-carriage of fusC and pvl genes was present in 7 MRSA and in one MSSA.

Conclusion

LFI shows excellent diagnostic accuracy indices for rapid identification of PVL in MSSA/MRSA in a setting with high prevalence of pvl^+ve strains. The high occurrence of pvl and fusC genes in MRSA strains causing SSTI is of concern and needs constant surveillance.

Molecular analysis of an increase in trimethoprim/sulfamethoxazole-resistant MRSA reveals multiple introductions into a tertiary care hospital, Germany 2012-19

OBJECTIVES

Increasing spread of resistance could jeopardize the use of antifolates against MRSA infections.

METHODS

We compared the prevalence of phenotypic trimethoprim/sulfamethoxazole resistance in 20 534 clinical Staphylococcus aureus isolates (19 096 MSSA and 1438 MRSA) of non-redundant patients at Heidelberg University Hospital over 8 years and performed WGS on trimethoprim/sulfamethoxazole-resistant MRSA.

RESULTS

From 2012 to 2019, trimethoprim/sulfamethoxazole resistance in MSSA (674/19 096; 3.5%) ranged between 1.5% and 7.2% and in MRSA (135/1438; 9.4%) between 0.5% and 20.2%, reaching a peak in 2016 and 2018, respectively (Ptrend < 0.001). Trimethoprim/sulfamethoxazole resistance was more likely in outpatients than inpatients (P = 0.005), younger patients (P < 0.001), skin and soft tissue infections (SSTIs) (MRSA only, P = 0.05), submissions from pulmonology (MRSA only, P = 0.001), the upper respiratory tract (MSSA only, P < 0.001) and general surgery (MSSA only, P = 0.001). WGS of 76 trimethoprim/sulfamethoxazole-resistant MRSA revealed that 59% belonged to major pandemic CA-MRSA clones (ST22, ST8, ST398, ST772, ST30), 47% harboured Panton-Valentine leucocidin (PVL), 97% SCCmec IV/V, 71% dfrG and 28% dfrA. SNP-based phylogeny of trimethoprim/sulfamethoxazole-resistant MRSA core genomes favoured independent introduction over clonal expansion as the source, most prominently of dfrA+ trimethoprim/sulfamethoxazole-resistant ST22 MRSA from the Gaza Strip.

CONCLUSIONS

The presented results support that trimethoprim/sulfamethoxazole-resistant S. aureus, formerly associated with SSTI from outpatients and S. aureus in the (sub)tropics, is on the rise in the temperate zone, potentially due to migration. Closer monitoring of trimethoprim/sulfamethoxazole resistance in S. aureus is recommended to safeguard the effectiveness of antifolate compounds.

Surveillance for Colonization, Transmission, and Infection With Methicillin-Susceptible Staphylococcus aureus in a Neonatal Intensive Care Unit

IMPORTANCE

Staphylococcus aureus is one of the leading causes of infections in neonatal intensive care units (NICUs). Most studies in this patient group focus on methicillin-resistant S aureus or the outbreak setting, whereas data for methicillin-susceptible S aureus are limited.

OBJECTIVES

To identify risk factors for S aureus colonization and infections in hospitalized newborns and to investigate S aureus transmission and its dynamics in a nonoutbreak setting.

DESIGN, SETTING, AND PARTICIPANTS

This monocentric cohort study in a tertiary NICU in Heidelberg, Germany, enrolled all hospitalized neonates (n = 590) with at least 1 nasal screening swab positive for S aureus. Data were collected from January 1, 2018, to December 31, 2019.

EXPOSURES

Weekly screening for S aureus colonization was performed for all newborns until discharge.

MAIN OUTCOMES AND MEASURES

The primary end point was any S aureus infection until hospital discharge. Transmission of S aureus and performance of routine typing to detect transmissions were defined as the secondary outcomes of the study.

RESULTS

In total, 590 newborns were enrolled (276 [46.8%] female and 314 [53.2%] male; 220 [37.3%] with birthweight <1500 g; 477 [80.8%] preterm; 449 [76.1%] singletons; 419 [71.5%] delivered via cesarean section). The median length of stay was 26 (range, 10-62) days. Overall, 135 infants (22.9%) were colonized by S aureus at some time during their hospital stay. The median time to first detection was 17 (interquartile range, 11-37) days. The overall incidence of S aureus infection was 1.7% (10 of 590). Low birth weight (<1500 g [odds ratio, 9.3; 95% CI, 5.9-14.6; P < .001]) and longer hospital stay (odds ratio, 2.3; 95% CI, 1.9-2.7; P < .001) were associated with colonization. Nasal carriage was significantly associated with S aureus infection (odds ratio, 8.2; 95% CI, 2.1-32.3; P = .002). A total of 123 of 135 colonization isolates were sequenced. All recoverable infection isolates (4 of 7) of newborns with colonization were genetically identical to the colonizing isolate. Whole-genome sequencing indicated 23 potential transmission clusters.

CONCLUSIONS AND RELEVANCE

The findings of this cohort study suggest that nasal colonization is a relevant risk factor for S aureus infection in a nonoutbreak NICU setting. In colonized newborns, infection and colonization isolates were genetically identical, suggesting that eradication of colonization may be a useful measure to prevent infection. Further investigations are necessary to validate and assess the generalizability of our findings.

[Rate of methicillin-resistant Staphylococcus aureus in pediatric emergency departments in Spain]

INTRODUCTION

Staphylococcusaureus (S. aureus) is a common germ present in bacterial infections in children. Lately, the rate of methicillin-resistant S. aureus (MRSA) is increasing.

OBJECTIVES

The main aim of this study is to know the rate of positive cultures to MRSA in Spanish pediatric emergency departments. The secondary aims are to analyze the risk factors for MRSA isolation (patient origin, history of hospitalization or surgery in the previous 90 days, antibiotherapy in the previous 60 days, presence of comorbidity, invasive devices, prior MRSA isolation) and to analyze the morbidity of these infections.

METHODOLOGY

Retrospective multicenter study (07/01/2017-06/30/2018) with review of patient histories with isolation of S. aureus in samples of any origin obtained in 8 pediatric emergency departments of the Infectious Diseases Working Group of the Spanish Society of Pediatric Emergencies.

RESULTS

During this period, S. aureus was detected in 403 patients (average age 75.8±59.2 months; 54.8% male): 28.8% hospital-related infections and 71.2% community-related infections. Overall, MRSA rate was 16.6% (95% CI: 13-20.2%); 18.1% in hospital-related infections and 16.2% in community-related infections (P>.05). The highest rates of MRSA were obtained in skin abscesses (29.3%, 95% CI: 21.8-36.8%), patients not born in Spain (52%; 95% CI: 32-72%) or patients with a previous MRSA infection (90%; 95% CI: 71.4-100%). 167 (41%) patients were admitted, 12 (3%) had complications and 4 (1%) suffered sequels. There were no deaths.

CONCLUSIONS

The overall MRSA rate was one in six staphylococcal infections. Higher MRSA rates were detected in samples of suppurating skin injuries and in foreign children or in children with a history of previous MRSA infection. In suppurative skin lesions, early drainage is essential and the change to an antibiotic with MRSA coverage should be considered if the evolution is inadequate.

Increasing Incidences and Clonal Diversity of Methicillin-Resistant Staphylococcus aureus in the Nordic Countries - Results From the Nordic MRSA Surveillance

Methicillin-resistant Staphylococcus aureus (MRSA) is notifiable in Denmark, Finland, Iceland, Norway and Sweden. The prevalence of MRSA in this region has been low for many years, but all five countries experience increasing numbers of new cases. The aim of the study was to describe the molecular epidemiology in the Nordic countries 2009-2016. Numbers of new cases of MRSA from 1997 to 2016 were compared, and a database containing information on spa-type and place of residence or acquisition, for all new MRSA isolates from 2009 to 2016 was established. A website was developed to visualize the geographic distribution of the spa-types. The incidence of new MRSA cases increased in all Nordic countries with Denmark having 61.8 new cases per 100,000 inhabitants in 2016 as the highest. The number of new cases 2009 to 2016 was 60,984. spa-typing revealed a high genetic diversity, with a total of 2,344 different spa-types identified. The majority of these spa-types (N = 2,017) were found in 1-10 cases. The most common spa-types t127/CC1, t223/CC22, and t304/CC6:8 increased significantly in all Nordic countries during the study period, except for Iceland, while spa-type t002/CC5 decreased in the same four countries. The trends of other common spa-types were different in each of the Nordic countries. The Nordic countries were shown to share similar trends but also to have country-specific characteristics in their MRSA populations. A continued increasing numbers of MRSA will challenge the surveillance economically. A more selected molecular surveillance will probably have to be employed in the future.

Genomic structure of ST8-t008 USA300 and USA300-LV MRSA in the Rhine-Neckar Region, Germany, 2012-2018

OBJECTIVE

Methicillin-resistant Staphylococcus aureus (MRSA) ST8-t008 of the pulsotype USA300 and the Latin American variant (USA300-LV) are the predominant virulent MRSA clonal lineages on the American continent. In Europe, the occurrence of USA300 or USA300-LV has often been related to international travel or outbreaks in hospitals. The replacement of local epidemic MRSA clones by these hypervirulent clones has not yet been demonstrated in Europe. This study aimed to gain insight into the genetic relatedness of ST8-t008 MRSA encountered in previous studies in the Rhine-Neckar Region, Germany, and ST8-t008 MRSA from other geographic regions.

METHODS

Nineteen ST8-t008 MRSA isolated between 2012 and 2018 were compared with publicly available sequences of ST8-t008 MRSA from travellers returning from the tropics, and USA300 and USA300-LV that were previously encountered in Europe.

RESULTS

We identified 14 of 19 (73.7%) of the local ST8-t008 MRSA being related to USA300 and five of 19 (26.3%) belonging to the USA300-LV cluster. Four suspected transmission clusters were identified without any evidence of in-hospital transmission.

CONCLUSION

The genetic relatedness of these local strains to publicly available sequences of ST8-t008 MRSA from other parts of Europe and to MRSA of travellers returning from the tropics pointed to multiple introductions into Germany. However, four suspected transmission clusters may be an indication of transmission within the community.

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.

Staphylococcus aureus Nasal Colonization in Spanish Children. The COSACO Nationwide Surveillance Study

Objective

To assess the prevalence and risk factors for S. aureus and methicillin-resistant S. aureus (MRSA) nasal colonization in Spanish children.

Methods

Cross-sectional study of patients <14 years from primary care centers all over Spain. Clinical data and nasal aspirates were collected from March to July 2018.

Results

A total of 1876 patients were enrolled. Prevalence of S. aureus and MRSA colonization were 33% (95% CI 30.9–35.1) and 1.44% (95% CI 0.9–2), respectively. Thirty-three percent of the children (633/1876) presented chronic conditions, mainly atopic dermatitis, asthma and/or allergy (524/633). Factors associated with S. aureus colonization were age ≥5 years (OR 1.10, 95% CI 1.07–1.12), male sex (OR 1.43, 95% CI 1.17–1.76), urban setting (OR 1.46, 95% CI 1.08–1.97) and the presence of asthma, atopic dermatitis or allergies (OR 1.25; 95% CI: 1.093–1.43). Rural residence was the only factor associated with MRSA colonization (OR 3.62, 95% CI 1.57–8.36). MRSA was more frequently resistant than methicillin-susceptible S. aureus to ciprofloxacin [41.2% vs 2.6%; p<0.0001], clindamycin [26% vs 16.9%; p=0.39], and mupirocin [14.3% vs 6.7%; p=0.18]. None of the MRSA strains was resistant to tetracycline, fosfomycin, vancomycin or daptomycin.

Conclusions

The main risk factors for S. aureus colonization in Spanish children are being above five years of age, male gender, atopic dermatitis, asthma or allergy, and residence in urban areas. MRSA colonization is low, but higher than in other European countries and is associated with rural settings.

Genotyping of methicillin resistant Staphylococcus aureus from the United Arab Emirates

Reports from Arabian Gulf countries have demonstrated emergence of novel methicillin resistant Staphylococcus aureus (MRSA) strains. To address the lack of data from the United Arab Emirates (UAE), genetic characterisation of MRSA identified between December 2017 and August 2019 was conducted using DNA microarray-based assays. The 625 MRSA isolates studied were grouped into 23 clonal complexes (CCs) and assigned to 103 strains. CC5, CC6, CC22 and CC30 represented 54.2% (n/N = 339/625) of isolates with other common CCs being CC1, CC8, CC772, CC361, CC80, CC88. Emergence of CC398 MRSA, CC5-MRSA-IV Sri Lanka Clone and ST5/ST225-MRSA-II, Rhine-Hesse EMRSA/New York-Japan Clone in our setting was detected. Variants of pandemic CC8-MRSA-[IVa + ACME I] (PVL+) USA300 were detected and majority of CC772 strains were CC772-MRSA-V (PVL+), “Bengal- Bay Clone”. Novel MRSA strains identified include CC5-MRSA-V (edinA+), CC5-MRSA-[VT + fusC], CC5-MRSA-IVa (tst1+), CC5-MRSA-[V/VT + cas + fusC + ccrA/B-1], CC8-MRSA-V/VT, CC22-MRSA-[IV + fusC + ccrAA/(C)], CC45-MRSA-[IV + fusC + tir], CC80-MRSA-IVa, CC121-MRSA-V/VT, CC152-MRSA-[V + fusC] (PVL+). Although several strains harboured SCC-borne fusidic acid resistance (fusC) (n = 181), erythromycin/clindamycin resistance (ermC) (n = 132) and gentamicin resistance (aacA-aphD) (n = 179) genes, none harboured vancomycin resistance genes while mupirocin resistance gene mupR (n = 2) and cfr gene (n = 1) were rare. An extensive MRSA repertoire including CCs previously unreported in the region and novel strains which probably arose locally suggest an evolving MRSA landscape.

Diagnostic tools for bacterial infections in travellers: Current and future options

International travel has increased dramatically over the past 50 years, and travel destinations have diversified. Although physicians are more familiar with the panel of aetiological agents responsible for illnesses of returning travellers, thanks to regular epidemiological studies, the spectrum of pathogens potentially encountered in various travel destinations is nevertheless increasing. In addition, the wide array of approaches currently available and addressed in this paper could render the procedures for microbiological analyses increasingly complex. As the time to result is crucial to adequately manage patients, modern approaches have been developed to shorten diagnosis delays. The syndromic approach, which consists of simultaneously testing a wide panel of microorganisms, substantially increases the diagnostic yield with significant time savings, particularly when coupled with point-of-care laboratories. The tools commonly used for this purpose are immunochromatographic tests, mainly targeting bacterial antigens, and multiplex real-time PCR. The emergence of next-generation sequencing technologies, which enable random amplification of genetic material of any microbe present in a clinical specimen, provides further exciting perspectives in the diagnosis of infectious diseases.

International travel as source of a hospital outbreak with an unusual meticillin-resistant Staphylococcus aureus clonal complex 398, Denmark, 2016

In May 2016, an unusual outbreak with the Panton-Valentine leukocidin-positive human variant of meticillin-resistant Staphylococcus aureus (MRSA) clonal complex 398 occurred among mothers and infants in the maternity unit of a Danish hospital. MRSA sharing genotypic and phenotypic characteristics was confirmed in 36 cases, including 26 patients, nine household members and a healthcare worker (HCW) who had contact with all the patients. The national MRSA database contained 37 seemingly unlinked MRSA cases whose isolates shared the same genotypic and phenotypic characteristics as the outbreak strain. Whole genome sequencing showed that three of these isolates clustered together with the 36 outbreak isolates, suggesting spread outside the hospital. The HCW and 21 of 37 cases from the national MRSA database had links to south-eastern Asia, where the outbreak strain is endemic. These findings suggest that the HCW acquired the outbreak strain while travelling in south-eastern Asia and then introduced it into the hospital; from there, it spread within the patients’ households and into the community. Screening of travellers returning from countries with high levels of MRSA could be an important intervention to prevent spread of these bacteria into hospitals via patients or HCWs.

Entry of Panton-Valentine leukocidin-positive methicillin-resistant Staphylococcus aureus into the hospital: prevalence and population structure in Heidelberg, Germany 2015-2018

Staphylococcus aureus is one of the major pathogens causing community—and healthcare-acquired infections. The presence of the virulence factor Panton–Valentine leukocidin (PVL) is associated with recurrent infection and clinical severity and generally regarded as a feature of community associated-methicillin-resistant Staphylococcus aureus (MRSA). To date, the focus of PVL-positive MRSA in hospitalized patients has been on outbreaks. We aimed to investigate whether PVL-positive MRSA has penetrated the community-hospital barrier by determining the prevalence of PVL in MRSA of hospitalized patients. MRSA strains isolated from patients hospitalized > 48 h in Heidelberg University Hospital between 2015 and 2018 Isolates were analysed for the presence of PVL and subjected to spa-typing. PVL-positive MRSA were then characterized by whole genome sequencing. We analysed 740 MRSA isolates in the study period and identified 6.2% (n = 46) PVL-positivity. 32.6% of PVL-positive MRSA met the criteria for nosocomial acquisition. The most frequent clones among the PVL-positive strains were ST80-t044 (21.7%, n = 10/46) and ST8-t008 (19.5%, n = 9/46). WGS identified three possible transmission clusters involving seven patients. In conclusion, we found successful epidemic PVL-positive MRSA clones entering the hospital and causing nosocomial infections. Preventive measures and constant surveillance should be maintained to prevent transmissions and clonal outbreaks.

Levonadifloxacin, a recently approved benzoquinolizine fluoroquinolone, exhibits potent in vitro activity against contemporary Staphylococcus aureus isolates and Bengal Bay clone isolates collected from a large Indian tertiary care hospital

OBJECTIVES

Levonadifloxacin (WCK 771; IV) and its prodrug alalevonadifloxacin (WCK 2349; oral) are benzoquinolizine fluoroquinolones, recently approved in India for the treatment of acute bacterial skin and skin structure infections with concurrent bacteraemia and diabetic foot infections. Ahead of its market launch, the present study aimed to assess the in vitro activity of levonadifloxacin against contemporary Staphylococcus aureus isolates collected from a large tertiary care hospital in India. Additionally, levonadifloxacin activity was tested against hVISA and Bengal Bay clone MRSA isolates.

METHODS

Non-duplicate S. aureus (n = 793) isolates collected at Christian Medical College hospital, Vellore, India during 2013-19 were included in the study. MRSA isolates were identified using a cefoxitin disc diffusion assay. MICs of levonadifloxacin and comparator antibiotics were determined using the broth microdilution method. Mutations in QRDRs were identified for selected levofloxacin-non-susceptible isolates. MLST profiling was undertaken to detect the Bengal Bay clone.

RESULTS

Among the 793 isolates, 441 (55.6%) were MRSA and 626 (78.9%) were non-susceptible to levofloxacin. Levonadifloxacin showed MIC50 and MIC90 values of 0.25 and 0.5 mg/L, respectively, for all S. aureus, which included hVISA and Bengal Bay clone MRSA. The potency of levonadifloxacin was 16 times superior compared with levofloxacin.

CONCLUSIONS

The present study demonstrated potent activity of levonadifloxacin against contemporary S. aureus isolates, which included MRSA isolates, hVISA isolates, Bengal Bay clone isolates and a high proportion of quinolone-non-susceptible isolates. The potent activity of levonadifloxacin observed in this study supports its clinical use for the treatment of S. aureus infections.

Panton-Valentine leukocidin-positive Staphylococcus aureus in skin and soft tissue infections from primary care patients

OBJECTIVES

To characterize deep skin and soft tissue infections (dSSTI) caused by Panton-Valentine leukocidin (PVL)-positive versus PVL-negative Staphylococcus aureus isolates.

METHODS

We performed a retrospective analysis of patients' records including S. aureus isolates from outpatients with dSSTI. Samples had been submitted by primary care physicians, i.e. general practitioners, surgeons, dermatologists and paediatricians, located in Berlin, Germany, in 2007-2017. Bacterial isolates were identified and tested for antimicrobial susceptibility by VITEK 2; PVL was detected by PCR.

RESULTS

In total, 1199 S. aureus isolates from 1074 patients with dSSTI were identified, and 613 (51.1%) of 1199 samples were PVL⁺. The median age of patients with PVL⁺S. aureus was lower than in patients with PVL- S. aureus (34 years, range 0-88 years, vs. 44 years, range 0-98 years; p < 0.0001). PVL was associated with repeated/multiple samples compared to single sample submission (69/92, 75% vs. 448/982, 45.6%, p < 0.0001; odds ratio (OR), 3.6; 95% confidence interval (CI), 2.2-5.8). Interestingly, the highest PVL positivity rate was found in isolates from gluteal (82/108, 75.9%; OR, 3.6; 95% CI, 2-5) or axillary (76/123, 61.8%; OR, 2; 95% CI, 1.1-3.3) localizations compared to isolates from the arm. The PVL positivity rate did not increase over time. Yet we noticed an increase in the trimethoprim/sulfamethoxazole (SXT) resistance rate in PVL⁺ isolates, mainly methicillin-sensitive S. aureus, when considering SXT resistance rates of 2007-2012 versus 2013-2017 (35/226, 15.5% vs. 74/289, 25.6%; p 0.01).

CONCLUSIONS

In outpatients, gluteal and axillary dSSTI are indicative of PVL⁺S. aureus. Providing SXT as a complementary treatment for dSSTI should be based on susceptibility testing.

Repeated introduction and spread of the MRSA clone t304/ST6 in northern Europe

OBJECTIVES

During the last decades several methicillin-resistant Staphylococcus aureus (MRSA) clones with the capability of global spread have emerged in the community. Here, we have investigated a large collection of clinical isolates belonging to MRSA clone t304/ST6, which has emerged in many European countries over the last years, in order to retrace its phylogeny and its spread.

METHODS

We characterized 466 ST6 isolates from Denmark (n = 354), France (n = 10), Norway (n = 24), Sweden (n = 27) and the UK (n = 51). All had spa-type t304 (n = 454) or t304-related spa-types (n = 12) and whole genome sequencing (WGS) was carried out on Illumina Miseq or Hiseq with 100-300 bp reads. cgMLST was performed using Ridom SeqSphere.

RESULTS

A minimum spanning tree (MST) of all 466 isolates showed one large cluster including 182 isolates collected only from Denmark and related to a long-term neonatal outbreak in Copenhagen. This cluster contrasted with numerous small clusters, including the remaining Danish isolates and isolates from the other countries that interspersed throughout the tree. Most isolates were Panton-Valentine leukocidin (PVL) negative (95%) and harboured SCCmec IVa. One genome was closed using Oxford Nanopore technology and Illumina MiSeq. It contained a plasmid of 19.769 bp including the blaZ gene. A similar plasmid was found in 78% of all isolates.

DISCUSSION

t304/ST6 is a successful emerging clone and the fact that isolates from five countries are interspersed throughout the MST indicates a common origin. This clone is commonly described in the Middle East and its emergence in Europe coincides with influx of refugees from the Syrian Civil War.

Antibiotic-resistant pathogens in different patient settings and identification of surveillance gaps in Switzerland - a systematic review

The prevalence of antimicrobial resistance (AMR) varies significantly among different patient populations. We aimed to summarise AMR prevalence data from screening studies in different patient settings in Switzerland and to identify surveillance gaps. We performed a systematic review, searching Pubmed, MEDLINE, Embase (01/2000–05/2017) and conference proceedings for Swiss studies reporting on carbapenemase-producing Enterobacteriaceae (CPE), extended-spectrum beta-lactamases (ESBL), mobilised colistin-resistance, methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE) within different patient settings. We identified 2345 references and included 46 studies. For acute care patients, most screening data come from admission screenings, whereas AMR prevalence among hospitalised patients is largely unknown. Universal admission screenings showed ESBL-prevalences of 5–8% and MRSA-prevalences of 2–5%. For targeted screening, ESBL-prevalence ranged from 14–21%; MRSA-prevalence from 1–4%. For refugees, high ESBL (9–24%) and MRSA (16–24%) carriage rates were reported; returning travellers were frequently (68–80%) colonised with ESBL. Screening data for other pathogens, long-term care facility (LTCF) residents and pediatric populations were scarce. This review confirms high ESBL- and MRSA-carriage rates for risk populations in Switzerland. Emerging pathogens (CPE and VRE) and certain populations (inpatients, LTCF residents and children) are understudied. We encourage epidemiologists and public health authorities to consider these findings in the planning of future surveillance studies.

Community-associated Staphylococcus aureus PVL+ ST22 predominates in skin and soft tissue infections in Beijing, China

Purpose

Community-associated Staphylococcus aureus (CA S. aureus) is the most common causative pathogen of the skin and soft tissue infections (SSTIs). This study aims to determine clonal distribution, virulence factors of CA S. aureus clinical isolates from purulent SSTIs in Beijing, China.

Materials and methods

CA-S. aureus isolates were collected from 115 outpatients with purulent SSTIs from the department of dermatology from April 2015 to April 2017. Multilocus sequence typing and Staphylococcus cassette chromosome mec typing were performed to explore molecular characteristics. Phylogenetic analysis of 16S rRNA of dominant S. aureus isolates was performed using MEGA-X software. Virulence genes were detected by PCR, while biofilm formation was evaluated by a microtiter plate method. The antimicrobial susceptibility was tested by an automatic VITEK system.

Results

Forty-four CA-S. aureus isolates identified from SSTIs contain 9 methicillin-resistant S. aureus (MRSA) isolates (20.4%) and 35 methicillin-susceptible S. aureus isolates (MSSA) (79.6%). The dominant sequence types (STs) were ST22 (40.9%) and clonal complex 59 (CC59; 77.8%) in Community-associated methicillin resistant methicillin-resistant S. aureus. 27.8% of ST22 isolates were homologous to the epidemic ST22 EMRSA-15 in Europe. The prevalence of virulence genes lukS/lukF, tst-1, etA, edinA, icaA, and icaD was 50%, 93.2%, 4.5%, 4.5%, 100%, and 100%, respectively. All CC59 isolates exhibited stronger biofilm-forming capability than ST22 clones. Among the MSSA subgroup, the poor biofilm producers had significantly higher sensitivity to sulfamethoxazole/Trimethoprim.

Conclusion

The dominant epidemic clone PVL⁺ ST22 MSSA containing tst-1 occurs in Beijing, indicating that a PVL⁺ ST398 clone which was previously predominant in this district had been replaced by a new clone.

Methicillin-resistant Staphylococcus aureus (MRSA) in East Africa: red alert or red herring?

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) is associated with significant morbidity and mortality and has resultant important economic and societal costs underscoring the need for accurate surveillance. In recent years, prevalence rates reported in East Africa have been inconsistent, sparking controversy and raising concern.

METHODS

We described antimicrobial susceptibility patterns of Staphylococcus aureus isolates cultured from patients within the Internal Medicine department of the largest public healthcare facility in East and Central Africa- the Kenyatta National Hospital (KNH) in Nairobi, Kenya. Routine antimicrobial susceptibility data from non-duplicate Staphylococcus aureus isolates cultured between the years 2014-2016 from the medical wards in KNH were reviewed.

RESULTS

Antimicrobial susceptibility data from a total of 187 Staphylococcus aureus isolates revealed an overall MRSA prevalence of 53.4%. Isolates remained highly susceptible to linezolid, tigecycline, teicoplanin and vancomycin.

CONCLUSIONS

The prevalence of MRSA was found to be much higher than that reported in private tertiary facilities in the same region. Careful interrogation of antimicrobial susceptibility results is important to uproot any red herrings and reserve genuine cause for alarm, as this has a critical bearing on health and economic outcomes for a population.

Genomic and Epidemiological Evidence of a Dominant Panton-Valentine Leucocidin-Positive Methicillin Resistant Staphylococcus aureus Lineage in Sri Lanka and Presence Among Isolates From the United Kingdom and Australia

Objective: To undertake the first detailed genomic analysis of methicillin-resistant Staphylococcus aureus (MRSA) isolated in Sri Lanka. Methods: A prospective observational study was performed on 94 MRSA isolates collected over a 4 months period from the Anuradhapura Teaching Hospital, Sri Lanka. Screening for mecA, mecC, and the Panton-Valentine leucocidin (PVL)-associated lukS-PV/lukF-PV genes and molecular characterization by spa typing was undertaken. Whole genome sequencing (WGS) and phylogenetic analysis was performed on selected multilocus sequence type (MLST) clonal complex 5 (CC5) isolates from Sri Lanka, England, Australia, and Argentina. Results: All 94 MRSA harbored the mecA gene. Nineteen spa types belonging to nine MLST clonal complexes were identified. Where origin of the sample was recorded, most isolates were from skin and soft tissue infections (70/91; 76.9%), with fewer causing bacteremia (16/91; 17.6%), empyema (3/91; 3.3%) and osteomyelitis (2/91; 2.2%). Sixty two (65.9%) isolates were PVL positive with the majority (56 isolates; 90.3%) belonging to a dominant CC5 lineage. This lineage, PVL-positive ST5-MRSA-IVc, was associated with both community and hospital-onset infections. Based on WGS, representative PVL-positive ST5-MRSA-IVc isolates from Sri Lanka, England and Australia formed a single phylogenetic clade, suggesting wide geographical circulation. Conclusions: We present the most detailed genomic analysis of MRSA isolated in Sri Lanka to date. The analysis identified a PVL-positive ST5-MRSA-IVc that is prevalent among MRSA causing clinical infections in Sri Lanka. Furthermore, this clone was also found among isolates from the United Kingdom and Australia.