Tuesday, 6 December 2011

MRSA st398 responsible for bloodstream infections?


Events become ever more ominous for Britain's vetocracy.

Their attempt to start a trade war with the Americans on the issue of antibiotic resistance is doomed to total failure.

Attempts to start smoke screens will be swamped by the avalanche of science linking MRSA st398 to human illness and the curious absence of MRSA st398 in British pigs.

Everyone will want to know how this miracle was achieved.

We think we can tell them.

Full report here

Methicillin-Susceptible ST398 Staphylococcus aureus Responsible for Bloodstream Infections: An Emerging Human-Adapted Subclone?


Abstract 


In the course of an annual 3-month bloodstream infections (BSI) survey conducted during a four-year period in 31 healthcare institutions located in three noncontiguous French regions, we report 18 ST398 Staphylococcus aureus BSI. ST398 BSI incidence showed a seven-fold increase during the study period (0.002 per 1,000 patient days in 2007 vs. 0.014 in 2010). ST398 BSI isolates differed from the pig-borne multiresistant clone: 17/18 BSI isolates were methicillin susceptible and none was of t011, t034 or t108 pig-borne spa-types. ST398 BSI isolates had homogenous resistance patterns (15/18 with only Eryr) and prophagic content (all harboured the hlb-converting Sau3int phage).


The clustering of BSI and pig-borne isolates by spa-typing and MLVA, the occurrence of Sau3int phage in BSI isolates and the lack of this phage in pig-borne isolates suggest that the emergence of BSI isolates could have arisen from horizontal transfer, at least of the Sau3int phage, in genetically diverse MSSA ST398 isolates. The acquisition of the phage likely plays a role in the increasing ability of the lysogenic ST398 isolates to colonize human. The mode of acquisition of the non pig-borne ST398 isolates by our 18 patients remains unclear. ST398 BSI were diagnosed in patients lacking livestock exposure and were significantly associated with digestive portals of entry (3/18 [16.7%] for ST398 vs. 19/767 [2.5%] for non ST398 BSI; p = .012). This raises the question of possible foodborne human infections. We suggest the need for active surveillance to study and control the spread of this human-adapted subclone increasingly isolated in the hospital setting.

The last words of the Conclusion on the full version are worth noting too:

We found that a digestive portal of entry was much more common among ST398 compared to other S. aureus BSIs, lending weight to the hypothesis of foodborne transmission. Further farm-to-fork studies are required to elucidate the possible role of food, especially retail meat samples including beef, pork and chicken, as a source of human infection.