Secular trends and dynamics of hospital associated methicillin-resistant Staphylococcus aureus

Molecular Epidemiology, Antimicrobial Susceptibility, and Clinical Features of Methicillin-Resistant Staphylococcus aureus Bloodstream Infections over 30 Years in Barcelona, Spain (1990-2019)

Methicillin-resistant Staphylococcus aureus bloodstream infections (MRSA-BSI) are a significant cause of mortality. We analysed the evolution of the molecular and clinical epidemiology of MRSA-BSI (n = 784) in adult patients (Barcelona, 1990−2019). Isolates were tested for antimicrobial susceptibility and genotyped (PFGE), and a selection was sequenced (WGS) to characterise the pangenome and mechanisms underlying antimicrobial resistance. Increases in patient age (60 to 71 years), comorbidities (Charlson’s index > 2, 10% to 94%), community-onset healthcare-associated acquisition (9% to 60%), and 30-day mortality (28% to 36%) were observed during the 1990−1995 and 2014−2019 periods. The proportion of catheter-related BSIs fell from 57% to 20%. Current MRSA-BSIs are caused by CC5-IV and an upward trend of CC8-IV and CC22-IV clones. CC5 and CC8 had the lowest core genome proportions. Antimicrobial resistance rates fell, and only ciprofloxacin, tobramycin, and erythromycin remained high (>50%) due to GyrA/GrlA changes, the presence of aminoglycoside-modifying enzymes (AAC(6′)-Ie-APH(2″)-Ia and ANT(4′)-Ia), and mph(C)/msr(A) or erm (C) genes. Two CC22-IV strains showed daptomycin resistance (MprF substitutions). MRSA-BSI has become healthcare-associated, affecting elderly patients with comorbidities and causing high mortality rates. Clonal replacement with CC5-IV and CC8-IV clones resulted in lower antimicrobial resistance rates. The increased frequency of the successful CC22-IV, associated with daptomycin resistance, should be monitored.

Emergence of the European ST80 clone of community-associated methicillin-resistant Staphylococcus aureus as a cause of healthcare-associated infections in Eastern Algeria

AIMS

The authors had for aim to assess whether an in-hospital spread of the European community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) clone was on-going in Annaba, Eastern Algeria.

MATERIAL AND METHODS

We carried out a molecular epidemiological study of S. aureus strains causing infections in 4 hospitals located in Annaba, between February and October 2010.

RESULTS

Our study revealed a very low healthcare-associated MRSA (HCA-MRSA) infection incidence rate of 0.34 per 1000 patient-days. However, the rates of HCA-MRSA strains (85/119) and CA-MRSA (7/29) among S. aureus strains are much higher than those found in France. The European CA-MRSA clone (clonal complex 80, Staphylococcal Cassette Chromosome mec IVc, spa type t044, lukS/F-PV-positive) accounted for 14.1% of all healthcare-associated (HCA) MRSA infections.

CONCLUSION

This study confirmed the emerging role of CA-MRSA as HCA pathogens in North-African Africa.

Resistance mechanisms and epidemiology of multiresistant pathogens in Europe and efficacy of tigecycline in observational studies

OBJECTIVES

Antimicrobial drug resistance is a growing problem in Europe and, even with differences in epidemiology, it is of great concern. The treatment of complicated skin and soft-tissue infections (cSSTIs) and complicated intra-abdominal infections (cIAIs) is hindered further by pathogens that are resistant to methicillin, carbapenems, third-generation cephalosporins and glycopeptides.

PATIENTS AND METHODS

An analysis of the microbiological results from five European observational studies (July 2006 to October 2011) evaluating the efficacy of tigecycline (prescribed as monotherapy or in combination with other antibacterials) for the treatment of cSSTI and cIAI is presented.

RESULTS

In total, 213 cSSTI and 623 cIAI patients were included; 34.4% and 56.6%, respectively, were critically ill in intensive care units. At baseline, at least one pathogen was isolated in 167 (78.4%) cSSTI and 464 (74.5%) cIAI patients, and 32.9% and 49.1% of infections were polymicrobial. In cSSTI, Staphylococcus aureus and Escherichia coli (52.7% and 18.0%, respectively) were the most frequently isolated pathogens, whereas in cIAI most infections were due to E. coli (41.8%), Enterococcus faecium (40.1%) and Enterococcus faecalis (21.1%). Clinical response was observed in >80% of patients with E. coli in both cIAI and cSSTI. In cSSTI patients, the clinical response rate to S. aureus was 80.8%. For cIAI, 77.4% of E. faecium and 79.5% of E. faecalis patients responded to treatment.

CONCLUSIONS

Tigecycline when given alone or in combination with other antibacterials appeared to be efficacious against multiple pathogens, affirming its role in real-life clinical practice as a broad-spectrum antibacterial for the treatment of patients with cSSTI and cIAI, including the critically ill, across Europe.