Characteristics of methicillin-resistant Staphylococcus aureus in patients on admission to a teaching hospital in Rio de Janeiro, Brazil

Can habits and behaviors predict colonization by community-associated MRSA in patients admitted to a Brazilian hospital?

This study aimed to identify factors associated with colonization by community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in adult patients admitted to a Brazilian hospital. This is a cross-sectional study, in which patients underwent a nasal swab and were asked about hygiene behavior, habits, and clinical history. Among the 702 patients, 180 (25.6%) had S. aureus and 21 (2.9%) MRSA. The factors associated with MRSA colonization were attending a gym (OR 4.71; 95% CI; 1.42 - 15.06), smoking habit in the last year (OR 2.37; 95% CI; 0.88 - 6.38), previous hospitalization (OR 2.18; CI 95%; 0.89 - 5.25), and shared personal hygiene items (OR 1.99; 95% CI; 0.71 - 5.55). At the time of admission, colonization by CA-MRSA isolates was higher than that found in the general population. This can be an important public health problem, already endemic in hospitals, whose factors such as those associated with habits (smoking cigarettes) and behaviors (team sports practice and activities in gyms) have been strongly highlighted. These findings may help developing infection control policies, allowing targeting patients on higher-risk populations for MRSA colonization.

Activity of arginine-phenylalanine and arginine-tryptophan-based surfactants against Staphylococcus aureus

Aims: This study aimed to evaluate the antibacterial effect of two new cationic surfactants based on phenylalanine-arginine (LPAM) and tryptophan-arginine (LTAM). Materials & methods: Antibacterial activity, mechanism of action and interactions with Staphylococcus aureus enzymes were measured through microbiological, flow cytometry and molecular docking assays, respectively. Results & conclusion: These compounds showed antibacterial activity in the range of 4.06-16.24 μg/ml against planktonic cells and no activity against mature biofilms, since they caused a loss of membrane integrity and increased DNA damage, as revealed by flow cytometry analysis. In silico assays revealed the existence of molecular bonds such as hydrogen bonds, mainly with DNA. Therefore, these compounds have promising pharmacological activity against MRSA strains.

Prevalence and antimicrobial resistance profile of Staphylococcus aureus in inherited epidermolysis bullosa: a cross-sectional multicenter study in Brazil

BACKGROUND

Infection is an important complication of epidermolysis bullosa (EB), and Staphylococcus aureus has been pointed out as the most common pathogen among this population. The objective of this study was to investigate the prevalence and antimicrobial resistance profile of S. aureus colonizing EB patients in Brazil.

METHODS

This cross-sectional multicenter study was conducted between December 2015 and December 2017. We included a total of 89 individuals with EB from medical centers across Brazil. Data were obtained through clinical and bacteriological investigation. S. aureus were identified by biochemical tests. The nuc and mecA genes were confirmed by PCR assay. Antimicrobial susceptibility was investigated by disk diffusion method.

RESULTS

The overall prevalence of S. aureus was 51.7% (46/89). Methicillin-resistant S. aureus (MRSA) was detected in 24.7% (19/77) of all S. aureus isolates, colonizing 15.7% (14/89) of all patients. Community-associated (CA)-MRSA strains were resistant against sulfamethoxazole/trimethoprim and levofloxacin (P < 0.05%). S. aureus colonization of the nares and belly button represented a 3.4 times higher risk of simultaneous skin lesion colonization (P < 0.05%).

CONCLUSIONS

The high frequency of MRSA colonizing patients with EB is alarming considering its association with life-threatening complications and poorer outcomes. EB patients are at increased risk of colonization and infection by Staphylococcus aureus and CA-MRSA. Getting to know S. aureus carriage sites and its antimicrobial susceptibility profile is key when planning new individualized and more effective prophylactic and therapeutic measures.

The History of Methicillin-Resistant Staphylococcus aureus in Brazil

Since the emergence of MRSA in the 1960s, a gradual increase in infections by resistant bacteria has been observed. Clinical manifestations may vary from brand to critical condition due to host risk factors, as well as pathogen virulence and resistance. The high adaptability and pathogenic profile of MRSA clones contributed to its spread in hospital and community settings. In Brazil, the first MRSA isolates were reported in the late 1980s, and since then different genetic profiles, such as the Brazilian epidemic clone (BEC) and other clones considered a pandemic, became endemic in the Brazilian population. Additionally, Brazil's MRSA clones were shown to be able to transfer genes involved in multidrug resistance and enhanced pathogenic properties. These events contributed to the rise of highly resistant and pathogenic MRSA. In this review, we present the main events which compose the history of MRSA in Brazil, including numbers and locations of isolation, as well as types of staphylococcal cassette chromosome mec (SCCmec) found in the Brazilian territory.

Genotypic distribution of Staphylococcus aureus colonizing children and adolescents in daycare centers, an outpatient clinic, and hospitals in a major Brazilian urban setting

Staphylococcus aureus nasal colonization is a major risk factor for infection. Studies have suggested an epidemiologic shift in the methicillin-resistant S. aureus (MRSA) strains that circulate in Brazil. We conducted cross-sectional studies of MRSA carriage among 1) children and adolescents in community daycare centers, 2) an outpatient clinic, and 3) hospitals in a large Brazilian metropolitan setting. There were 1.500 study subjects, 500 from each locale: 768 (51.2%) carried S. aureus whereas 150 (10%) of these were colonized with MRSA. The most common lineages were the Southwest Pacific (SWP) and the Pediatric clones in all three groups. Roughly 50% of SWP carried Panton-Valentine leukocidin (PVL) (p < 0.01) genes while 63.3% of the Pediatric clones were resistant or intermediately resistant to erythromycin (p < 0.01). This study describes a clonal change of the Brazilian epidemic clone (BEC) to the Pediatric and SWP lineages in Brazil. This finding has implications for clinical management of MRSA infections.

Prevalence of oxacillin-susceptible methicillin-resistant Staphylococcus aureus nasal carriage and their clonal diversity among patients attending public health-care facilities

Context

Nosocomial infections arise from many microorganisms, including Staphylococcus aureus.

Aims

The aim of this study is to determine the molecular epidemiology of circulating methicillin-resistant S. aureus (MRSA) clones among patients attending community and health-care facilities in Nova Friburgo, RJ, Brazil.

Methods

A total of 1002 nasal swab samples were collected from May 2010 to September 2015. S. aureus isolates were identified through phenotypic tests, submitted to antimicrobial susceptibility tests and genotypic analysis to detect mecA, panton-valentine leucocidin (PVL) genes, SCCmec, SPA and multilocus sequencing typing (MLST) typing.

Results

We identified 294 (29.3%) isolates as S. aureus and 91 (9.1%) as MRSA. A total of 17 isolates did not present a correlation between phenotypic and genotypic resistance profiles. Among MRSA isolates, 17 (18.7%) carried PVL genes. A total of 20 different SPA types were determined, being grouped by MLST into eight different sequence types. ST5/t002 was the most prevalent genotype found among these isolates.

Conclusions

There is a gradual colonisation shift happening in the infection pattern by S. aureus in Brazil. The Brazilian Epidemic Clone (ST239-SCCmec IIIa-PVL-) seems to be substituted by isolates from different clonal complexes, such as ST5, ST8 and ST30. The non-correlation between phenotypic/genotypic resistance profile observed in some isolates suggests the presence of other methicillin resistance mechanisms different from mecA presence or a difference in the nucleotide sequence, which prevents the primers to identify the specific region during polymerase chain reaction reactions. MRSA identification should be based on phenotypic and genotypic testing to ensure the various types of resistance mechanisms.

MRSA dynamic circulation between the community and the hospital setting: New insights from a cohort study

Dissemination of methicillin-resistant-Staphylococcus aureus/(MRSA) is a worldwide concern both in hospitals [healthcare-associated-(HA)-MRSA] and communities [community-associated-(CA)-MRSA]. Knowledge on when and where MRSA colonization is acquired and what clones are involved is necessary, to focus efforts for prevention of hospital-acquired MRSA-infections.

METHODS

A prospective/longitudinal cohort study was performed in eight Argentina hospitals (Cordoba/ October-December/2014). Surveillance cultures for MRSA (nose-throat-inguinal) were obtained on admission and at discharge. MRSA strains were genetically typed as CA-MRSA_G and HA-MRSA_G genotypes.

RESULTS

Overall, 1419 patients were screened and 534 stayed at hospital for ≥3 days. S. aureus admission prevalence was 30.9% and 4.2% for MRSA. Overall MRSA acquisition rate was 2.3/1000 patient-days-at-risk with a MRSA acquisition prevalence of 1.96% (95%CI: 1.0%-3.4%); 3.2% of patients were discharged back to community with MRSA. CA-MRSA_G accounted for 84.6% of imported, 100.0% of hospital-acquired and 94% of discharged MRSA strains. Most imported and acquired MRSA strains belonged to two major epidemic CA-MRSA clones spread in Argentina: PFGEtypeI-ST5-IVa-t311-PVL⁺ and PFGEtypeN/ST30-IVc-t019-PVL⁺.

CONCLUSIONS

CA-MRSA clones, particularly ST5-IV-PVL⁺ and ST30-IV-PVL⁺, with main reservoir in the community, not only enter but also are truly acquired within hospital, causing healthcare-associated-hospital-onset infections, having a transmission capacity greater or similar than HA-MRSA_G. This information is essential to develop appropriate MRSA infection prevention-control programs, considering hospital and community.

Daptomycin and vancomycin non-susceptible methicillin-resistant Staphylococcus aureus clonal lineages from bloodstream infection in a Brazilian teaching hospital

INTRODUCTION

This study aimed to characterize Staphylococcus aureus isolates from bloodstream infections in patients attending a teaching hospital, between 2011 and 2015.

METHODS

The minimum inhibitory concentration for daptomycin, linezolid, oxacillin, teicoplanin, vancomycin, and trimethoprim/sulfamethoxazole was accessed by broth microdilution. SCCmec type and clonal profile were determined by molecular tests. Vancomycin heteroresistance was evaluated using screening tests and by population analysis profile/area under the curve.

RESULTS

Among 200 S. aureus isolates, 55 (27.5%) were MRSA, carrying SCCmec II (45.5%) or IV (54.5%). The most frequent MRSA lineages were USA100 (ST5-II) (45.5%) and USA800 (ST5-IV) (30.9%). Six isolates were confirmed as vancomycin heteroresistant, showing area under the curve ratio 1.1, 1.2 or 1.3 (four USA100, one USA800 and one USA1100 isolates).

CONCLUSIONS

Daptomycin and vancomycin non-susceptible MRSA clonal lineages were found in bloodstream infections over five years, highlighting the importance of continuous surveillance of multiresistant bacteria in hospitals.

Cross-transmission in the Dental Office: Does This Make You Ill?

PURPOSE OF REVIEW

Recently, numerous scientific publications were published which shed new light on the possible risks of infection for dental healthcare workers and their patients. This review aimed to provide the latest insights in the relative risks of transmission of (pathogenic) micro-organisms in the dental office.

RECENT FINDINGS

Of all different routes of micro-organism transmission during or immediately after dental treatment (via direct contact/via blood-blood contact/via dental unit water and aerosols), evidence of transmission is available. However, the recent results put the risks in perspective; infections related to the dental office are most likely when infection control measures are not followed meticulously.

SUMMARY

The risk for transmission of pathogens in a dental office resulting in an infectious disease is still unknown; it seems to be limited in developed countries but it cannot be considered negligible. Therefore, maintaining high standards of infection preventive measures is of high importance for dental healthcare workers to avoid infectious diseases due to cross-contamination.