Abstract
While many data on molecular epidemiology of MRSA are available for North America, Western Europe and Australia, much less is known on the distribution of MRSA clones elsewhere. Here, we describe a poorly known lineage from the Middle East, CC1153, to which several strains from humans and livestock belong. Isolates were characterised using DNA microarrays and one isolate from the United Arab Emirates was sequenced using Nanopore technology. CC1153 carries
agr
II and capsule type 5 genes. Enterotoxin genes are rarely present, but PVL is common. Associated
spa
types include t504, t903 and t13507. PVL-positive CC1153-MSSA were found in Egyptian cattle suffering from mastitis. It was also identified among humans with skin and soft tissue infections in Saudi Arabia, France and Germany. CC1153-MRSA were mainly observed in Arabian Gulf countries. Some isolates presented with a previously unknown SCC
mec
/SCC
fus
chimeric element in which a
mec
B complex was found together with the fusidic acid resistance gene
fusC
and accompanying genes including
ccrA/B-
1 recombinase genes. Other isolates carried SCC
mec
V elements that usually also included
fusC
. Distribution and emergence of CC1153-MRSA show the necessity of molecular characterization of MRSA that are resistant to fusidic acid. These strains pose a public health threat as they combine resistance to beta-lactams used in hospitals as well as to fusidic acid used in the community. Because of the high prevalence of
fusC
-positive MRSA in the Middle East, sequences and descriptions of SCC elements harbouring
fusC
and/or
mecA
are reviewed. When comparing
fusC
and its surrounding regions from the CC1153 strain to available published sequences, it became obvious that there are four
fusC
alleles and five distinct types of
fusC
gene complexes reminiscent to the
mec
complexes in SCC
mec
elements. Likewise, they are associated with different sets of
ccrA/B
recombinase genes and additional payload that might include entire
mec
complexes or SCC
mec
elements.