Distribution of the ACME-arcA gene among meticillin-resistant Staphylococcus haemolyticus and identification of a novel ccr allotype in ACME-arcA-positive isolates

Abstract

The aim of this study was to investigate the prevalence and characteristics of ACME (arginine catabolic mobile element)-arcA-positive isolates among meticillin-resistant Staphylococcus haemolyticus (MRSH). ACME-arcA, native arcA and SCCmec elements were detected by PCR. Susceptibilities to 10 antimicrobial agents were compared between ACME-arcA-positive and -negative isolates by chi-square test. PFGE was used to investigate the clonal relatedness of ACME-arcA-positive isolates. The phylogenetic relationships of ACME-arcA and native arcA were analysed using the neighbour-joining methods of MEGA software. A total of 42 (47.7 %) of 88 isolates distributed in 13 PFGE types were positive for the ACME-arcA gene. There were no significant differences in antimicrobial susceptibility between ACME-arcA-positive and -negative isolates. A novel ccr allotype (ccrAB SHP ) was identified in ACME-arcA-positive isolates. Among 42 ACME-arcA-positive isolates: 8 isolates harboured SCCmec V, 8 isolates harboured class C1 mec complex and ccrAB SHP ; 22 isolates harbouring class C1 mec complex and 4 isolates harbouring class C2 mec complex were negative for all known ccr allotypes. The ACME-arcApositive isolates were first found in MRSH with high prevalence and clonal diversity, which suggests a mobility of ACME within MRSH. The results from this study revealed that MRSH is likely to be one of the potential reservoirs of ACME for Staphylococcus aureus.

Arginine Catabolic Mobile Element Is Associated With Low Antibiotic Resistance and Low Pathogenicity in Staphylococcus epidermidis From Neonates

“…Our finding is in line with the study by Diep et al (8), in which 67% (18/27) of S. epidermidis isolates from nostrils were ACME positive, and Miragaia et al (11), in which 51% (65/127) of S. epidermidis isolates from different sources and widespread geographical origin were ACMEpositive. A recent study also showed a high prevalence (48%) of ACME in Staphylococcus haemolyticus isolates (24). In this study, a higher prevalence of ACME was found in S. epidermidis isolates considered as contaminants (most likely derived from the skin) compared with invasive disease causing isolates.…”

“…In this study, a higher prevalence of ACME was found in S. epidermidis isolates considered as contaminants (most likely derived from the skin) compared with invasive disease causing isolates. It has been suggested that L-arginine catabolism contributes to optimize staphylococcal life on the acidic human skin, which may explain the high prevalence of ACME in typically skin colonizing coagulase-negative Staphylococci (CoNS), such as S. epidermidis and S. haemolyticus (10,24). Transfer of ACME from CoNS to the USA300 MRSA clone may also explain why USA300 frequently is colonizing skin regions (e.g.…”

“…Miragaia et al, in contrast, found that in geographically diverse S. epidermidis isolates, the vast majority of ACME containing isolates belonged to a large clonal complex. There is now compelling evidence that ACME is widely distributed among different CoNS-species, and that CoNS may act as a reservoir for ACME being transferred to specific clonal lineages of S. aureus (8,11,24).…”

Arginine Deiminase in Staphylococcus epidermidis Functions To Augment Biofilm Maturation through pH Homeostasis

“…(14,15), Listeria monocytogenes (16), Staphylococcus spp. (17)(18)(19), and Pseudomonas spp. (20); arginine can serve as the sole energy source for growth of a variety of bacteria, including the streptococci (21) and Pseudomonas aeruginosa (22).…”

Carriage of an ACME II Variant May Have Contributed to Methicillin-Resistant Staphylococcus aureus Sequence Type 239-Like Strain Replacement in Liverpool Hospital, Sydney, Australia

“…In this regard, the arc gene cluster (arcCBDAR) encodes a complete arginine deiminase pathway, which converts L-arginine to carbon dioxide, ATP, and ammonia, the last of which is important for survival at low pH (4). In general, ACME allotypes (and variants thereof) are broadly associated with certain coagulase-negative staphylococci (CoNS) (2,10,12). ACME carriage is uncommon in MRSA isolates, with the exception of USA300 (ST8-MRSA-IVa), for which evidence suggests that carriage has contributed to the successful spread of this community clone; a previous study showed that deletion of ACME I resulted in a fitness loss for a USA300 strain in a rabbit bacteremia model (5).…”