Molecular analysis of community-acquired methicillin-susceptible and resistant Staphylococcus aureus isolates recovered from bacteraemic and osteomyelitis infections in children from Tunisia

Abstract

Thirty-six children (27 boys, nine girls) that fulfilled CDC criteria for community-acquired infections were diagnosed with bacteraemia and/or osteomyelitis caused by Staphylococcus aureus during an 18-month period (2006-2008). Antibiotic susceptibility was determined by an agar dilution method. SCCmec type, carriage of pvl genes, agr type and spa-typing were determined using specific PCR protocols. Clonal relatedness was examined by pulsed field gel electrophoresis-SmaI and mutilocus sequence typing techniques. From the 36 isolates, eight (22%) corresponded to methicillin-resistant Staphylococcus aureus (MRSA) -t044/042-CC80/CC5-IVc-pvl(+) -agrIII/II. The highest genetic diversity was observed among the 28 community-acquired methicillin-susceptible S. aureus (CA-MSSA) isolates: 22 spa-variants that also grouped by multilocus sequence typing in CC1, CC5, CC6, CC8, CC30, CC80, CC97 and the singletons ST464, ST1467, ST1468 and ST1469. The pvl genes were detected in all eight CA-MRSA isolates and in eight CA-MSSA isolates (28%), being significantly more frequent among isolates causing osteoarticular infection (11 of 12, 92%) than in the bacteraemic isolates (six of 24, 25%). Based on patients' age, three groups were considered: newborns, infants and children. Bacteraemia was diagnosed in all newborns and infants, whereas in 42% of the children group osteomyelitis was the unique presentation. In most cases, the portal of entry was either the skin or unknown. In general, favourable outcome was observed, except in four cases-three of whom had severe complications and one died. In summary, we analysed the epidemiological and genetic background of community-acquired staphylococcal strains causing bacteraemic and/or osteomyelitis infections in children from Tunisia, describing three new sequence types and one novel spa type.

Clonal lineages detected amongst tetracycline-resistant meticillin-resistant Staphylococcus aureus isolates of a Tunisian hospital, with detection of lineage ST398

“…Similar isolates have been mainly described in Central Europe (Aires de Sousa & de Lencastre, 2003;Deurenberg & Stobberingh, 2008). Kechrid et al (2011) reported the spread of MRSA t044/t042-ST728-CC80 in isolates recovered from bacteraemic and osteomyelitis infections in children from Tunisia.…”

“…Currently, there are no data about the presence of MRSA CC398 in Muslim countries, in which pork is not consumed. Thus, in Tunisia, some reports have described the detection of different clonal lineages of MRSA in samples from human and animal origins (Ben Nejma et al, 2013;Ben Slama et al, 2011;Gharsa et al, 2012;Kechrid et al, 2011;Mariem et al, 2013). However, no MRSA ST398 isolates have been identified in hospitals in Tunisia.…”

Predictors of Mortality in Staphylococcus aureus Bacteremia

“…PVL is associated with diseases such as skin and soft tissue infections (22), osteoarticular infections (137), and necrotizing pneumonia (78). With the exception of necrotizing pneumonia (79), PVL has not been found to be associated with increased mortality rates, including SAB (16,212,311,314).…”

Bacteriostatic and Bactericidal effects of ethyl acetate root bark extract of Terminalia avicennioides on Methicillin-resistant Staphylococcus aureus

“…Initially, MRSA strains have been suffered by patients with chronic illnesses, until the emergence of CA-MRSA strains in the 1990s. The CA-MRSA strains became epidemic, causing skin and soft tissue infections (SSTIs), including some with severe consequences, such as community-acquired pneumonia (Francis et al, 2005), pyomyositis (Burdette et al, 2012), sepsis, osteomyelitis (Kechrid et al, 2011) and necrotizing fasciitis (Changchien et al, 2011). The methicillin-resistance is mediated by a penicillin binding protein encoded by mecA gene which aids the successful life cycle of the organism, and renders methicillin and other beta-lactam antibiotics ineffective.…”