Severe human bone infection due to methicillin-resistant Staphylococcus aureus carrying the novel mecC variant

ABSTRACT The in vitro activities of the novel 1β-methylcarbapenems J-111,225, J-114,870, and J-114,871, which have a structurally unique side chain that consists of a trans-3,5-disubstituted 5-arylpyrrolidin-3-ylthio moiety at the C-2 position, were compared with those of reference antibiotics. Among isolates of both methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MRCoNS), 90% were inhibited by J-111,347 (prototype), J-111,225, J-114,870, and J-114,871 at concentrations of 2, 4, 4, and 4 μg/ml (MICs at which 90% of isolates are inhibited [MIC90s]), respectively, indicating that these agents were 32- to 64-fold more potent than imipenem, which has an MIC90 of 128 μg/ml. Although these drugs were less active in vitro than vancomycin, which had MIC90s of 1 and 2 μg/ml for MRSA and MRCoNS, respectively, the new carbapenems displayed better killing kinetics than vancomycin. The potent anti-MRSA activity was ascribed to the excellent affinities of the new carbapenems for penicillin-binding protein 2a of MRSA. Since the new carbapenems also exhibited good activity against gram-positive and -negative bacteria including clinically important pathogens such as penicillin-resistantStreptococcus pneumoniae, Haemophilus influenzae, members of the family Enterobacteriaceae,Pseudomonas aeruginosa, and Clostridium difficile, as well as MRSA, the novel carbapenems are worthy of further evaluation.

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Identification of a Plasmid-Borne Resistance Gene Cluster Comprising the Resistance Genes erm(T), dfrK, and tet(L) in a Porcine Methicillin-Resistant Staphylococcus aureus ST398 Strain

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01091-09 ◽

2009 ◽

Vol 54 (2) ◽

pp. 915-918 ◽

Cited By ~ 46

Author(s):

Kristina Kadlec ◽

Stefan Schwarz

Keyword(s):

Staphylococcus Aureus ◽

Gene Cluster ◽

Resistance Gene ◽

Streptococcus Pyogenes ◽

Methicillin Resistant Staphylococcus Aureus ◽

Tetracycline Resistance ◽

Sequence Type ◽

The Novel ◽

Methicillin Resistant ◽

Resistance Gene Cluster

ABSTRACT A novel plasmid-borne resistance gene cluster comprising the genes erm(T) for macrolide-lincosamide-streptogramin B resistance, dfrK for trimethoprim resistance, and tet(L) for tetracycline resistance was identified in a porcine methicillin-resistant Staphylococcus aureus sequence type 398 (ST398) strain. This erm(T)-dfrK-tet(L) region was flanked by copies of the novel IS element ISSau10. The erm(T) region resembled that of Streptococcus pyogenes plasmid pRW35. The erm(T) gene of pKKS25 was expressed constitutively due to a 57-bp deletion in the erm(T) translational attenuator.

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Novel Type of Staphylococcal Cassette Chromosome mec in a Methicillin-Resistant Staphylococcus aureus Strain Isolated in Sweden

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00087-08 ◽

2008 ◽

Vol 52 (10) ◽

pp. 3512-3516 ◽

Cited By ~ 45

Author(s):

Carolina Berglund ◽

Teruyo Ito ◽

Megumi Ikeda ◽

Xiao Xue Ma ◽

Bo Söderquist ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Methicillin Resistant Staphylococcus Aureus ◽

Common Ancestor ◽

Aureus Strain ◽

The Novel ◽

Gene Complex ◽

Direct Repeats ◽

Methicillin Resistant ◽

Gene Complexes ◽

Staphylococcal Cassette Chromosome

ABSTRACT We identified a novel type of staphylococcal cassette chromosome mec (SCCmec) element carried by methicillin-resistant Staphylococcus aureus (MRSA) strain JCSC6082 isolated in Sweden. The SCCmec element was demarcated by characteristic nucleotide sequences at both ends and was integrated at the 3′ end of orfX. The element carried a novel combination of a type 5 ccr gene complex and class C1 mec gene complex. The J regions of the element were homologous to those of the SCCmercury element of S. aureus strain 85/2082, with nucleotide identity greater than 99%. However, the novel SCCmec element from JCSC6082 did not carry the mer operon nor Tn554, suggesting that evolution to SCCmec could have been from a common ancestor by acquisition of the class C1 mec gene complex. The novel SCCmec element from JCSC6082 was flanked by a novel SCC-like chromosome cassette (CC6082), which was demarcated by two direct repeats and could be excised from the chromosome independently of the SCCmec element. Our data suggest that novel SCCmec elements can be generated on the staphylococcal chromosome through the recombination between extant SCC elements and mec gene complexes.

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