The increase of methicillin-resistant Staphylococcus aureus (MRSA) and the presence of an unusual sequence type ST49 in slaughter pigs in Switzerland

Background: In years past, methicillin-resistant S. aureus (MRSA) has been frequently detected in pigs in Europe, North America and Asia. Recent, yet sporadic studies have revealed a low occurrence of MRSA in Switzerland. In 2009, a monitoring survey of the prevalence and genetic diversity of methicillin-resistant S. aureus (MRSA) in slaughter pigs in Switzerland was conducted using methods recommended by the EU guidelines, and using a sampling strategy evenly distributed throughout the year and representative of the Swiss slaughter pig population. Monitoring should determine if the overall prevalence of MRSA in the entire country is increasing over the years and if specific multi-resistant MRSA clones are spreading over the country.;Results: In 2009, the nasal cavities of eight out of 405 randomly selected pigs were positive for MRSA, representing a prevalence of 2.0% (95% CI 0.9-3.9). The following year, 23 out of 392 pigs were positive for MRSA [5.9% prevalence (95% CI 3.8-8.7)]. Three multilocus sequence types (ST), four spa types and two types of staphylococcal cassette chromosome mec (SCCmec) elements were detected. The most frequent genotypes were ST398 (MLST)-(spa)t034-V (SCCmec) (n = 18) and ST49-t208-V (n = 7), followed by ST398-t011-V (n = 4), ST398-t1451-V (n = 1), and ST1-t2279-IVc (n = 1). The isolates displayed resistance to beta-lactams [mecA, (31/31); blaZ, (19/31)]; tetracycline [tet(M), (31/31); tet(K), (30/31)] (n = 31); macrolides and lincosamides [erm(C) (4/31) or erm(A) (18/31)] (n = 22); tiamulin [vga(A)v (9/31) or unknown mechanism (18/31)] (n = 27); trimethoprim [dfr(G) (18/31); spectinomycin [ant(9)-Ia (19/31) or unknown mechanism (3/31)] (n = 22); streptomycin [str(19/31)]; sulphamethoxazole (7/31) and ciprofloxacin (n = 1) (mechanisms not determined).;Conclusions: This study is the first to describe the presence of MRSA ST49 in slaughter pigs, and to demonstrate a significant and nearly three-fold increase of MRSA prevalence in pigs within two years. The presence of a specific clonal lineage of MRSA from Switzerland suggests that it has been selected in Swiss pig husbandry. Effective hygiene measures should be enhanced within the entire pig production chain to suppress the spread of these pathogens into the community.

Prevalence of nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) in children a multicenter cross-sectional study

In this cross-sectional multicenter study, we determined the rate of nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) in children admitted to 9 training hospitals in Switzerland during 1 month. From 1337 patients, 1363 nasal swabs were obtained (mean age 6.1 years, median 4.7 years, interquartile range 1.3-10.4 years) and 562 (41.3%) grew S. aureus. Only one isolate was MRSA (0.18%) which encoded mecA and femA genes as well as SCCmec type IV, whereas Panton-Valentine leukocidin (PVL) was absent.

Comparative study of biphasic calcium phosphates with different HA/TCP ratios in mandibular bone defects. A long-term histomorphometric study in minipigs

Three biphasic calcium phosphate (BCP) bone substitute materials with hydroxyapatite (HA)/tricalcium phosphate (TCP) ratios of 20/80, 60/40, and 80/20 were compared to coagulum, particulated autogenous bone, and deproteinized bovine bone mineral (DBBM) in membrane-protected bone defects. The defects were prepared in the mandibles of 24 minipigs that were divided into four groups of six with healing times of 4, 13, 26, and 52 weeks, respectively. The histologic and histomorphometric evaluation focused on differences in amount and pattern of bone formation, filler degradation, and the interface between bone and filler. Collapse of the expanded polytetrafluoroethylene barrier membrane into the coagulum defects underlined the necessity of a filler material to maintain the augmented volume. Quantitatively, BCP 20/80 showed bone formation and degradation of the filler material similar to autografts, whereas BCP 60/40 and BCP 80/20 rather equaled DBBM. Among the three BCP's, the amount of bone formation and degradation of filler material seemed to be inversely proportional to the HA/TCP ratio. The fraction of filler surface covered with bone was highest for autografts at all time points and was higher for DBBM than BCP 80/20 and 60/40 at the early healing phase. TRAP-positive multinucleated cells were identified on BCP and DBBM surfaces without showing typical signs of resorption lacunae.

Daptomycin versus vancomycin for osteoarticular infections due to methicillin-resistant Staphylococcus aureus (MRSA): a nested case-control study

Vancomycin is the standard antibiotic for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. While daptomycin is approved for MRSA bacteremia, its effectiveness in osteoarticular infections (OAIs) has not been established. A 1:2 nested case-control study of adult patients with MRSA OAIs admitted to an academic center from 2005 to 2010 was carried out. Clinical outcomes and drug toxicity in patients treated with daptomycin versus vancomycin were compared. Twenty patients with MRSA OAIs treated with daptomycin were matched to 40 patients treated with vancomycin. The median age of the patients was 52 years (range, 25-90), and 40 (67 %) were male. Most patients had osteomyelitis (82 %), predominantly from a contiguous source (87 %). Forty percent were diabetics. Diabetic patients were more likely to receive vancomycin than daptomycin [20 (50 %) vs. 4 (20 %); p = 0.03]. Vancomycin was more often combined with antibiotics other than daptomycin [22 (55 %) vs. 5 (25 %); p = 0.03]. The median total antibiotic treatment duration was 48 (daptomycin) vs. 46 days (vancomycin) (p = 0.5). Ninety percent of daptomycin-treated patients had previously received vancomycin for a median of 14.5 days (range, 2-36). Clinical success rates were similar between daptomycin and vancomycin at 3 months [15 (75 %) vs. 27 (68 %); p = 0.8] and 6 months [14 (70 %) vs. 23 (58 %); p = 0.5], even after propensity score-based adjustment for antibiotic assignment. The frequency of adverse events was similar between treatment groups [1 (5 %) vs. 7 (18 %); p = 0.2]. Daptomycin and vancomycin achieved similar rates of clinical success and drug tolerability. Daptomycin is a reasonable alternative for treating MRSA OAIs, particularly in patients where therapy with vancomycin has not been well tolerated.

Nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) among Swiss veterinary health care providers: detection of livestock- and healthcare-associated clones.

We screened a total of 340 veterinarians (including general practitioners, small animal practitioners, large animal practitioners, veterinarians working in different veterinary services or industry), and 29 veterinary assistants for nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus pseudintermedius (MRSP) at the 2012 Swiss veterinary annual meeting. MRSA isolates (n = 14) were detected in 3.8 % (95 % CI 2.1 - 6.3 %) of the participants whereas MRSP was not detected. Large animal practitioners were carriers of livestock-associated MRSA (LA-MRSA) ST398-t011-V (n = 2), ST398-t011-IV (n = 4), and ST398-t034-V (n = 1). On the other hand, participants working with small animals harbored human healthcare-associated MRSA (HCA-MRSA) which belonged to epidemic lineages ST225-t003-II (n = 2), ST225-t014-II (n = 1), ST5-t002-II (n = 2), ST5-t283-IV (n = 1), and ST88-t186-IV (n = 1). HCA-MRSA harbored virulence factors such as enterotoxins, β-hemolysin converting phage and leukocidins. None of the MRSA isolates carried Panton-Valentine leukocidin (PVL). In addition to the methicillin resistance gene mecA, LA-MRSA ST398 isolates generally contained additional antibiotic resistance genes conferring resistance to tetracycline [tet(M) and tet(K)], trimethoprim [dfrK, dfrG], and the aminoglycosides gentamicin and kanamycin [aac(6')-Ie - aph(2')-Ia]. On the other hand, HCA-MRSA ST5 and ST225 mainly contained genes conferring resistance to the macrolide, lincosamide and streptogramin B antibiotics [erm(A)], to spectinomycin [ant(9)-Ia], amikacin and tobramycin [ant(4')-Ia], and to fluoroquinolones [amino acid substitutions in GrlA (S84L) and GyrA (S80F and S81P)]. MRSA carriage may represent an occupational risk and veterinarians should be aware of possible MRSA colonization and potential for developing infection or for transmitting these strains. Professional exposure to animals should be reported upon hospitalization and before medical intervention to allow for preventive measures. Infection prevention measures are also indicated in veterinary medicine to avoid MRSA transmission between humans and animals, and to limit the spread of MRSA both in the community, and to animal and human hospitals.

Evolution of methicillin-resistant Staphylococcus aureus (MRSA)

In 2009, a monitoring survey on the prevalence and genetic diversity of methicillin-resistant Staphylococcus aureus (MRSA) in slaughter pigs in Switzerland was started and revealed the presence of an unusual Multi Locus Sequence Type (ST49), which was detected for the first time in slaughter pigs worldwide. In addition to ST49, pigs also harboured ST398 and ST1. The prevalence of MRSA in slaughter pigs in Switzerland increased from 2.0% (95%CI 0.9-3.9) in 2009 to 5.9% (95% CI 3.8-8.7) in 2010, and remained stable in 2011 with 5,6% (95% CI 3.6-8.4). The increase was mainly due to the spread of ST398-t034, whereas ST49 was less frequently detected in 2010 and 2011. The presence of a specific sequence type (ST49) in MRSA from Switzerland suggests that it has been selected in local pig husbandry. However, MRSA of this lineage seems to have a lower potential for dissemination than ST398, which is increasingly detected in Swissslaughter pigs.

Evaluation of HA-fibrin-based hydrogel for restoration of degenerated intervertebral disc

Introduction: Intervertebral disc degeneration is associated with loss of nucleus pulposus (NP) tissue and reduced disc height[1]. A number of therapies, including synthetic and natural biomaterials, have been developed to restore full disc function and to minimize the pain and disability caused by this disease. Fibrin-based biomaterials are used as a replacement for NP or as a cell carrier for tissue engineering approaches[2]. While the behavior of such gels is well-characterized from a material point of view, little is known about their contribution to intervertebral disc (IVD) restoration under dynamic loads. The aim of the present study is the evaluation of a hyaluronic acid fibrin-based hydrogel (ProCore) used to repair an in vitro model of disc degeneration under dynamic loading. Methods: In vitro model of disc degeneration was induced in intact coccygeal bovine IVD by papain digestion of the NP as previously described[3]. In order to characterize fibrin hydrogels, four experimental groups were considered: 1) intact IVD (control), 2) IVD injected with PBS, 3) injection of hydrogels in degenerative IVD and 4) injection of hydrogels in combination with human bone marrow-derived mesenchymal stem cells (MSC) in degenerative IVD. All of the groups were subjected to dynamic loading protocols consisting of 0.2MPa static compression superimposed with ±2° torsion at 0.2Hz for 8h per day and maintained for 7 days. Additionally, one group consisted of degenerative IVD injected with hydrogel and subjected to static compression. Disc heights were monitored after the duration of the loading and compared to the initial disc height. The macrostructure of the formed tissue and the cellular distribution was evaluated by histological means. Results: After one week of loading, the degenerative IVD filled with hydrogel in combination with MSC (dynamic load), hydrogels (dynamic load) and hydrogels (static load) showed a reduction in height by 30%, 15% and 20%, respectively, as compared to their initial disc height. Histological sections showed that the HA-fibrin gel fully occupied the nucleotomized region of the disc and that fibrin was effective in filling the discontinuities of the cavity region. Furthermore, the cells were homogenously distributed along the fibrin hydrogels after 7 days of loading. Discussion: In this study, we showed that fibrin hydrogels showed a good integration within the papain-induced model of disc degeneration and can withstand the applied loads. Fibrin hydrogels can contribute to disc restoration by possibly maintaining adequate stiffness of the tissue and thus preventing disorganization of the surrounding IVD. References: 1. Jarman, J.P., Arpinar, V.E., Baruah, D., Klein, A.P., Maiman, D.J., and Tugan Muftuler, L. (2014). Intervertebral disc height loss demonstrates the threshold of major pathological changes during degeneration. Eur Spine J . 2. Colombini, A., Ceriani, C., Banfi, G., Brayda-Bruno, M., and Moretti, M. (2014). Fibrin in intervertebral disc tissue engineering. Tissue Eng Part B Rev . 3. Chan, S.C., Bürki, A., Bonél, H.M., Benneker, L.M., and Gantenbein-Ritter, B. (2013). Papain-induced in vitro disc degeneration model for the study of injectable nucleus pulposus therapy. Spine J 13, 273-283. Acknowledgement We thank the Swiss National Science Foundation SNF #310030_153411 for funding.