Search

Purpose: Community-acquired methicillin-resistant Staphylococcus aureus strains (CA-MRSA) are spread worldwide and often cause recurring and persistent infections in humans. CA-MRSA strains frequently carry Panton–Valentine leukocidin (PVL) as a distinctive virulence factor. This study investigates the molecular epidemiology, antibiotic resistance and clinical characteristics of PVL-positive MRSA strains in Northern Bavaria, Germany, isolated over an eight-year period. Methods: Strains were identified by MALDI-TOF MS and antibiotic susceptibility was tested by automated microdilution (VITEK 2) or disk diffusion. PVL-encoding genes and mecA were detected by PCR. MRSA clonal complexes (CC) and lineages were assigned by genotyping via DNA microarray and spa-typing. Results: In total, 131 PVL-positive MRSA were collected from five hospital sites between 2009 and 2016. Predominant lineages were CC8-MRSA-[IV+ACME], USA300 (27/131; 20.6%); CC30-MRSA-IV, Southwest Pacific Clone (26/131; 19.8%) and CC80-MRSA-IV (25/131; 19.1%). Other CCs were detected less frequently. Resistance against erythromycin and clindamycin was prevalent, whereas all strains were sensitive towards vancomycin and linezolid. In total, 100 cases (76.3%) were causally linked to an infection. The majority (102/131; 77.9%) of isolates were detected in skin swabs or swabs from surgical sites. Conclusions: During the sample period we found an increase in the PVL-positive MRSA lineages CC30 and CC1. Compared to less-abundant lineages CC1 or CC22, the predominant lineages CC8, CC30 and CC80 harbored a broader resistance spectrum. Furthermore, these lineages are probably associated with a travel and migration background. In the spatio-temporal setting we investigated, these were arguably drivers of diversification and change in the landscape of PVL-positive MRSA. [ABSTRACT FROM AUTHOR]

In 2011, an outbreak of hemorrhagic colitis and hemolytic uremic syndrome (HUS) was reported in Europe that was related to a hybrid STEAEC of Escherichia coli (E. coli) O104:H4 strain. The current study aimed to analyze strains of E. coli O104 and O9 isolated before 2011. The study included 47 strains isolated from children with and without diarrhea between 1986 and 2009 from different geographic regions, as well as seven reference strains. Serotyping was carried out on 188 anti-O and 53 anti-H sera. PCR was used to identify DEC genes and phylogenetic groups. Resistance profiles to antimicrobials were determined by diffusion in agar, while PFGE was used to analyze genomic similarity. Five serotypes of E. coli O104 and nine of O9 were identified, as well as an antigenic cross-reaction with one anti-E. coli O9 serum. E. coli O104 and O9 presented diarrheagenic E. coli (DEC) genes in different combinations and were located in commensal phylogenetic groups with different antimicrobial resistance. PFGE showed that O104:H4 and O9:(H4, NM) strains from SSI, Bangladesh and México belong to a diverse group located in the same subgroup. E. coli O104 and O9 were classified as commensal strains containing DEC genes. The groups were genetically diverse with pathogenic potential making continued epidemiologic surveillance important. [ABSTRACT FROM AUTHOR]