Clinical resistance and decreased susceptibility in Streptococcus suis isolates from clinically healthy fattening pigs

Streptococcus suis (S. suis) has often been reported as an important swine pathogen and is considered as a new emerging zoonotic agent. Consequently, it is important to be informed on its susceptibility to antimicrobial agents. In the current study, the Minimum Inhibitory Concentration (MIC) population distribution of nine antimicrobial agents has been determined for nasal S. suis strains, isolated from healthy pigs at the end of the fattening period from 50 closed or semiclosed pig herds. The aim of the study was to report resistance based on both clinical breakpoints (clinical resistance percentage) and epidemiological cutoff values (non-wild-type percentage). Non-wild-type percentages were high for tetracycline (98%), lincomycin (92%), tilmicosin (72%), erythromycin (70%), tylosin (66%), and low for florfenicol (0%) and enrofloxacin (0.3%). Clinical resistance percentages were high for tetracycline (95%), erythromycin (66%), tylosin (66%), and low for florfenicol (0.3%) and enrofloxacin (0.3%). For tiamulin, for which no clinical breakpoint is available, 57% of the isolates did not belong to the wild-type population. Clinical resistance and non-wild-type percentages differed substantially for penicillin. Only 1% of the tested S. suis strains was considered as clinically resistant, whereas 47% of the strains showed acquired resistance when epidemiological cutoff values were used. In conclusion, MIC values for penicillin are gradually increasing, compared to previous reports, although pigs infected with strains showing higher MICs may still respond to treatment with penicillin. The high rate of acquired resistance against tiamulin has not been reported before. Results from this study clearly demonstrate that the use of different interpretive criteria contributes to the extent of differences in reported antimicrobial resistance results. The early detection of small changes in the MIC population distribution of isolates, while clinical failure may not yet be observed, provides the opportunity to implement appropriate risk management steps

Effect of the enrichment medium on the detection and diversity of Salmonella from porcine duodenal content

This study assesses the effect of the enrichment medium used on the isolation of Salmonella from the duodenal content of naturally infected slaughter pigs. At six slaughterhouses, the duodenum was collected from 458 randomly chosen pigs and examined in the laboratory. Three semi-solid enrichment media (modified semisolid Rappaport-Vassiliadis medium [MSRV], diagnostic semi-solid Salmonella medium [DIASALM], and Simple Method Salmonella [SMS] agar) and three enrichment broths (Rappaport-Vassiliadis, Rappaport Vassiliadis broth with Soya [RVS], and Muller Kauffmann Tetrathionate novobiocin broth [MKTTn]) were evaluated. If a migration zone was present on the semi-solid media, a loopful was taken both near the inoculation drop and at the edge of the migration zone and streaked on a Xylose Lysine Desoxycholate (XLD) agar plate. Each enrichment broth was streaked on XLD, and three presumptive colonies were further examined. Detection rate was calculated, and isolates were, after serotyping, genotyped by performing pulsed-field gel electrophoresis (PFGE). The overall frequency of Salmonella isolated in at least one of the six different media was 15.5% (71/458). No significant differences in relative sensitivity were obtained within semi-solid media and within liquid media. Semi-solid media showed a significant higher relative sensitivity than the one obtained with liquid media. A relative sensitivity higher than 83.1%, namely of 94.4%, could only be obtained by combining three different enrichment media (MSRV or DIASALM+RVS+MKTTn). In 13.4% of the positive pigs, more than one serotype was found within the duodenum of one pig. In 12.9% of the duodenal contents, different genotypes were found within the same serotype. Differences in serotypes and genotypes were found predominantly within the same enrichment medium. In conclusion, to obtain the highest Salmonella detection rate in naturally contaminated pig samples, MSRV should be used as enrichment medium. However, to obtain a realistic picture of the sero-and genotypes present, different samples per enrichment medium and different enrichment media should be tested

Derived homotopy algebras

Derived A-algebras are derived and homotopy invariant versions of differential graded algebras. They were introduced by Steffen Sagave in 20 0 in order to construct minimal models for diferential graded algebras over arbitrary commutative rings. Muriel Livernet, Constanze Roitzheim, and Sarah Whitehouse showed in 2013 how they can be viewed as algebras over the minimal model of the operad encoding bicomplexes with a compatible associative multiplication. We extend their work for the associative operad to a general quadratic Koszul operad O satisfying standard projectivity assumptions. This leads to the new notion of derived homotopy O-algebra, where minimal models for O-algebras are defined. We explicitly compute generating operations and relations when O is the associative operad, the commutative operad, and the operad encoding Lie algebras

How HRM affects corporate financial performance: Evidence from Belgian SMEs.

In this paper, we provide a summary of several results from a study of HRM in small and medium-sized enterprises in Belgium. The central issue is whether the investment in HRM practices for smaller organizations is 'profitable'. This study differs in three ways from existing research. (1) It deals with the results from a survey of organizations with between 10 and 100 employees from various sectors. (2) In composing an index for 'HRM intensity', we started with a different interpretation of HRM practices, which also fits in more closely with the Belgian institutional context. (3) The operationalization of performance is based on a number of financial indicators which also help determine the 'state of health' of a company. Using the results of the survey, we examined the link between the score for HRM intensity, some performance outcomes and the financial performance of the organization using structural equation modeling. The results show that intensive HRM also offers added value for smaller organizations. Firstly, HRM intensification has a highly positive effect on productivity and, through productivity, reduces personnel costs/added value. This effect is sufficiently strong to compensate for the increased costs associated with intensive HRM. On top of this 'compensation effect', HRM intensity also has major effects on the profitability of the company.

How HRM affects corporate financial performance. Evidence from Belgian SMEs. Paper.

Employment; Expected; Managers; Studies; Management; Performance;