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In the Swiss pig population, only four sequence types (ST6, ST66, ST196, ST197) of Brachyspira ( B .) hyodysenteriae , an agent of Swine Dysentery (SD), have been so far detected suggesting a limited number of sources of B. hyodysenteriae in the Swiss pig production. A one year culture- and molecular-based diagnostic project was performed to identify and trace back B. hyodysenteriae in pig herds with SD, and to identify possible new STs. Up to five faecal swabs from herds with diarrhoea were examined. Three out of 141 herds tested positive for B. hyodysenteriae of ST196 (n=2) and ST66 (n=1). A common source was unlikely as none of the supplier herds or pig trader was shared and the occurrence was very low (2.1%) in the study population. This low occurrence may have resulted from the monitoring and eradications during the last ten years, emphasising their further applications to control B. hyodysenteriae.

Between July 2011 and May 2016, a total of 40 Staphylococcus aureus strains originating from 36 horses were confirmed as methicillin resistant (methicillin-resistant Staphylococcus aureus [MRSA]) in a university equine clinic. An additional 10 MRSA strains from 36 samples of clinic workers were obtained in October 2017. The first equine isolate represented the sequence type ST398, spa-type t011, and SCCmec IV. This isolate was resistant to a wide spectrum of antimicrobial agents. MRSA strains with the same genotype and with very similar resistance profiles were isolated on 21 more occasions from September 2013 to September 2014. A second outbreak occurred from May 2015 until May 2016. The first isolate in this second outbreak shared the same genotype, but was additionally resistant to chloramphenicol. The second isolate from August 2015 also showed resistance to rifampicin. The clone was isolated 18 times. Most of the human isolates shared the same genotype as the isolates from horses and their resistance patterns showed only slight differences. We can conclude that the MRSA-related cases at the Department and Clinic of Equine Medicine were all nosocomial infections caused by the same clonal lineage belonging to the clonal complex 398. The clonal complex 398 of equine origin is reported for the first time in Hungary. In addition, our observation of the emergence of new resistance to antimicrobial agents within the clonal lineage after treatment with antibiotics is of concern. Strict hygiene regulations have been introduced to lower the incidence of MRSA isolation and the related clinical disease.

In the Swiss veal calf production, antimicrobials and disinfectants are used to control bacterial infectious diseases, leading to a risk of selecting for a resistant bacterial population. While the prevalence of antibiotic resistance in E. coli from calves has been monitored at slaughterhouses in Switzerland since 2006, the resistance situation of E. coli from young calves entering the fattening period is not known. A total of 100 calves entering the fattening period in 20 geographically distant farms in Switzerland were screened for the presence of E. coli using rectal swabs in 2017. Genetic diversity between isolates was determined using repetitive palindromic Polymerase Chain Reaction (rep-PCR) revealing a genetically diverse E. coli population. Susceptibility to 13 antibiotics and to alkyldimethylbenzylammonium (ADBAC) was determined by the measurement of the minimal inhibitory concentration. Antibiotic and quaternary ammonium compound (QAC) resistance genes were identified using microarray and Polymerase Chain Reaction (PCR). Sixty-four percent of the isolates were resistant to at least one antibiotic, and 52% also exhibited decreased susceptibility to ADBAC. Resistance to more than 3 antibiotics was found in 40% of the isolates. Isolates exhibited resistance to tetracycline (57%) associated with the presence of tet genes (tet(A), (B), (E), (G)), to sulfonamides (61%) (sul1, sul2, sul3), ampicillin (56%) (blaTEM-1), trimethoprim (32%) (dfrA), phenicols (31%) (catA1, cmlA1, floR), gentamicin (27%) (ant(2")-Ia, aac(3)-IVa, aac(3)-VIa), and cefotaxime (2%) (blaCTX-M-14 (ESBL)). Mutations in GyrA (S83L) and ParC (S80I) were found in the fluoroquinolone-resistant isolates (6%). All isolates were susceptible to colistin, tigecycline and meropenem. No association between the presence of decreased susceptibility to ADBAC and qac genes was observed. In conclusion, antibiotic and QAC resistant E. coli are present in the gastrointestinal tract of young calves at the beginning of the fattening period, emphasizing the need for appropriate and reduced use of antibiotics and QAC-containing disinfectants in order to limit further selection of these bacteria during the fattening period.Antibiotika und Desinfektionsmittel werden in der Schweizer Kälbermast eingesetzt, mit dem Ziel Infek­tionskrankheiten zu bekämpfen. Dieser Einsatz birgt das Risiko der Selektion einer resistenten Bakterienpopulation. Obwohl die Prävalenz der Antibiotikaresistenzen von aus Kälbern an Schweizer Schlachthöfen seit 2006 isolierten E. coli überwacht wird, ist die Resistenzsitutation von E. coli zu Beginn der Mastperiode bisher nicht bekannt. Im Jahr 2017 wurden E. coli aus Kälbern von zwanzig Betrieben aus unterschiedlichen Regionen untersucht. Die dafür nötigen Kottupfer wurden zu Beginn der Mastperiode entnommen. Die genetischen Charakteristika der Isolate wurden mittels repetitiver palindromischer Polymerase Kettenreaktion (rep-PCR) bestimmt und weisen auf eine heterogene Population hin. Die Wirksamkeit von 13 Antibiotika sowie von alkyldimethylbenzylammonium (ADBAC) wurde mit Messung der minimalen inhibitorischen Konzentration (MHK) bestimmt. Die Gene, die für die Resistenz gegenüber den Antibiotika und den quaternären Ammoniumverbidungen (QAC) verantwortlich sind, wurden mittels Microarray und Polymerase Kettenreaktion (PCR) identifiziert. Sechsundsechzig der 100 Isolate waren gegen mindestens ein Antibiotikum resistent und 52% wiesen zusätzlich eine verminderte Empfindlichkeit gegen ADBAC auf. Vierzig Prozent der Isolate ­zeigten Resistenzen gegenüber mehr als 3 Antibiotika, darunter solche gegenüber Tetracyclin (57%) mit Vorhandensein der tet Gene (tet(A), (B), (E), (G)), Sulfonamide (61%) (sul1, sul2, sul3), Ampicillin (56%) (blaTEM-1), Trimethoprim (32%) (dfrA), Phenicol (31%) (catA1, cmlA1, floR), Gentamicin (27%) (ant(2“)-Ia, aac(3)-IVa, aac(3)-VIa), und Cefotaxim (2%) (blaCTX-M-14 (ESBL)). In flouroquinolonresistenten Isolaten (6%) wurden Mutationen in GyrA (S83L) and ParC (S80I) gefunden. Alle Isolate waren sensibel gegenüber Colistin, Tigecyclin und Meropenem. Es wurde kein Zusammenhang zwischen verminderter Empfindlichkeit gegenüber ­ADBAC und qac Genen beobachtet. Im Verdauungsapparat von Kälbern finden sich zu Beginn der Mastperiode E. coli, die gegenüber Antibiotika und QAC resistent sind. Dieser Befund verdeutlicht, dass ein angemessener Einsatz von Antibiotika und QAC-haltiger Desinfektionsmittel von Nöten ist, um die weitere Selektion dieser Bakterien während der Mastperiode zu begrenzen.Dans la production de veaux en Suisses, des antimicrobiens et des désinfectants sont utilisés pour contrôler les maladies infectieuses bactériennes, ce qui entraîne un risque de sélection d’une population bactérienne résistante. Si la prévalence de la résistance de E. coli aux antibiotiques chez les veaux est surveillée dans les abattoirs suisses depuis 2006, la situation de la résistance de E. coli chez les jeunes veaux au début de la période d’engraissement n’est pas connue. Un total de 100 veaux entrant dans la période d’engraissement dans 20 exploitations géographiquement éloignées de Suisse ont été testés en 2017 pour détecter la présence de E. Coli à l’aide de prélèvements rectaux. La diversité génétique entre les isolats a été déterminée à l’aide de la réaction de polymérase en chaîne répétitive palindrome (rep-PCR) révélant une population de E.coli génétiquement diversifié. La sensibilité à 13 antibiotiques et au chlorure d’alkyldiméthylbenzylammonium (ADBAC) a été déterminée par la mesure de la concentration inhibitrice minimale. Les gènes de résistance aux antibiotiques et aux composés d’ammonium quaternaire (QAC) ont été identifiés à l’aide d’une puce à ADN et de la réaction de polymérase en chaîne (PCR). Soixante-quatre pour cent des isolats étaient résistants à au moins un antibiotique et 52% présentaient également une diminution de la sensibilité à l’ADBAC. Une résistance à plus de 3 antibiotiques a été trouvée dans 40% des isolats. Les isolats présentaient une résistance à la tétracycline (57%) associée à la présence de gènes tet (tet (A), (B), (E), (G)), aux sulfonamides (61%) (sul1, sul2, sul3), à l’ampicilline (56%) (blaTEM-1), au triméthoprime (32%) (dfrA), aux phénicols (31%) (catA1, cmlA1, floR), à la gentamicine (27%) (ant(2'')-Ia, aac (3) -IVa, aac (3) -VIa) et à la céfotaxime (2%) (blaCTX-M-14 (BLSE)). Les isolats résistants aux fluoroquinolones (6%) présentaient des mutations dans GyrA (S83L) et ParC (S80I). Tous les isolats étaient sensibles à la colistine, à la tigécycline et au méropénème. Aucune association entre la présence d’une sensibilité diminuée à l’ADBAC et les gènes qac n’a été observée. En conclusion, des E. coli résistants aux antibiotiques et aux QAC sont présents dans le tractus gastro-intestinal des jeunes veaux au début de la période d’engraissement, ce qui souligne la nécessité d’un usage approprié et réduit d’antibiotiques et de désinfectants contenant un QAC afin de limiter la sélection ultérieure de ces bactéries au cours de la période d’engraissement.Nella produzione svizzera di vitelli da carne si usano antimicrobici e disinfettanti per il controllo delle malattie infettive batteriche, con il rischio di selezionare una popolazione batterica resistente. La prevalenza della resistenza agli antibiotici di E. coli è ben monitorata nei macelli svizzeri dal 2006, mentre la situazione dei giovani vitelli resistenti a E. coli che entrano nel periodo di ingrasso non è nota. Nel 2017, un totale di 100 vitelli entranti nel periodo di ingrasso provenienti da 20 aziende svizzere distanti tra loro sono stati sottoposti a screening, utilizzando tamponi rettali, per individuare la presenza di E. coli. La diversità genetica tra gli isolati à stata determinata usando una reazione a catena della polimerasi palindromica ripetitiva (rep-PCR) che ha rivelato una popolazione geneticamente diversa di E. coli. La sensibilità a 13 antibiotici e all’alchildimentilbenzilammonio (ADBAC) è stata determinata misurando la concentrazione minima inibitoria. I geni resistenti agli antibiotici e ai composti di ammonio quaternario (QAC) sono stati identificati mediante microarray e PCR. Il 64 percento degli isolati risultavano resistenti ad almeno un antibiotico e il 52% ha mostrato una minore sensibilità all’ADBAC. Nel 40% degli isolati si è rilevata una resistenza a più di 3 antibiotici. Gli isolati hanno mostrato una resistenza alla tetraciclina (57%) associata alla presenza di geni tet (tet(A), (B), (E), (G)), a sulfonamidi (61%) (sul1, sul2, sul3), a ampicillina (56%) (blaTEM-1), a trimetoprima (32%) (dfrA), a fenicoli (31%) (catA1, cmlA1, floR), a gentamicina (27%) (ant(2”)-Ia, aac(3)-IVa, aac(3)-VIa), e a cefotaxima (2%) (blaCTX-M-14 (ESBL)). Le mutazioni nel GyrA (S83L) e ParC (S80I) sono state riscontrate negli isolati resistenti ai fluorochinoloni (6%). Tutti gli isolati erano sensibili a colistina, tigeciclina e meropenem. Nessuna associazione è stata osservata tra la presenza di una ridotta sensibilità all’ADBAC e al QAC. In conclusione, l’E. coli resistente gli antibiotici e al QAC è presente nel tratto gastrointestinale dei vitelli all’inizio del periodo di ingrasso. Bisogna sottolineare la necessità di un uso appropriato e ridotto di antibiotici e disinfettanti contenenti QAC in modo da limitare l’ulteriore selezione di questi batteri durante il periodo di ingrasso.

Between July 2011 and May 2016, a total of 40

Worldwide emergence of antimicrobial-resistant Brachyspira (B.) hyodysenteriae led us question whether specific clones are present in Switzerland. Fifty-one B. hyodysenteriae isolates originating from 27 different Swiss pig herds sampled between 2010 and 2017 were characterised. Multilocus sequence typing revealed the presence of four different sequence types (STs) ST6, ST66, ST196 and ST197 with ST196 being predominant. Antimicrobial susceptibility to six different antimicrobial agents was determined by measurement of the minimal inhibitory concentration by broth dilution. Isolates were examined for the presence of point mutations and genes known to be associated with antimicrobial resistance in B. hyodysenteriae by PCR and sequence analysis. Forty-one isolates belonging to ST6 (n = 1), ST66 (n = 4) and ST196 (n = 36) exhibited decreased susceptibility to macrolides and lincomycin associated with an A2058 T/G mutation in the 23S rRNA gene. One isolate of ST66 and five isolates of ST196 exhibited decreased susceptibility to doxycycline associated with a G1058C mutation in the 16S rRNA gene. The Swiss B. hyodysenteriae population is characterised by a low genetic diversity, with macrolide-lincosamide-resistant isolates of ST196 being predominant.

The herd prevalence of third-generation cephalosporin-resistant Escherichia coli (3GC-R-Ec) was determined for broilers (25.0% [95% confidence interval (CI) 17.6-33.7%]), pigs (3.3% [(95% CI 0.4-11.5%]), and cattle (3.9% [95% CI 0.5-13.5%]), using a sampling strategy that was representative of the livestock population slaughtered in Switzerland between October 2010 and April 2011. The 3GC-R-Ec isolates were characterized by the measurement of the MICs of various antibiotics, microarray analyses, analytical isoelectric focusing, polymerase chain reaction and DNA sequencing for bla genes, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing. CMY-2 (n = 12), CTX-M-1 (n = 11), SHV-12 (n = 5), TEM-52 (n = 3), CTX-M-15 (n = 2), and CTX-M-3 (n = 1) producers were found. The majority of CMY-2 producers fell into 1 PFGE cluster, which predominantly contained ST61, whereas the CTX-M types were carried by heterogeneous clones of E. coli, as shown by the numerous PFGE profiles and STs that were found. This is the first national Swiss study that focuses on the spread of 3GC-R Enterobacteriaceae among slaughtered animals.

Bovine Bacillus anthracis isolates from Cameroon were genetically characterized. They showed a strong homogeneity, and they belong, together with strains from Chad, to cluster Aβ, which appears to be predominant in western Africa. However, one strain that belongs to a newly defined clade (D) and cluster (D1) is penicillin resistant and shows certain phenotypes typical of Bacillus cereus .

Methicillin resistance has emerged in clinical isolates of Staphylococcus pseudintermedius from cats in Switzerland. Three cats suffering from urinary tract infections were infected with methicillin-resistant S. pseudintermedius (MRSP). Phenotypic and genotypic characterization of the resistance profile showed that the isolates displayed resistance to all beta-lactams and cephalosporins (blaZ, mecA), fluoroquinolones, tetracyclines [tet(K)], macrolides, lincosamides and streprogramins B [erm(B)], chloramphenicol (catpC221), trimethoprim [dfr(G)] and the aminoglycosides gentamicin [aac(6')-Ie-aph(2')-Ia], kanamycin and neomycin [aph(3')-III] and streptomycin [ant(6)-Ia]. They also harbor the leukocidin gene lukS-I. MRSP represents a new challenge for antibiotic therapy and this zoonotic bacteria may rapidly spread to animals and humans.

The complete nucleotide sequences of six Actinobacillus porcitonsillarum plasmids pKMA202 (13.425-kb), pKMA1467 (11.115-kb), pKMA5 (9.549-kb), pIMD50 (8.751-kb), pKMA505 (8.632-kb) and pKMA757 (4.556-kb) and three Actinobacillus pleuropneumoniae plasmids pPSAS1522 (4.244-kb), pARD3079 (3.884-kb) and pKMA2425 (3.156-kb) were determined. All the plasmids contain the sulfonamide resistance gene sul2. One A. pleuropneumoniae plasmid and five A. porcitonsillarum plasmids also have the streptomycin resistance gene strA. Among these latter five A. porcitonsillarum plasmids, four also harbor the beta-lactam resistance gene bla(ROB-1). This study is the first report of multidrug resistance plasmids in the non-pathogenic A. porcitonsillarum.

We genotyped 15 Bacillus anthracis isolates from Chad, Africa, using multiple-locus variable-number tandem repeat analysis and three additional direct-repeat markers. We identified two unique genotypes that represent a novel genetic lineage in the A cluster. Chadian isolates were susceptible to 11 antibiotics and free of 94 antibiotic resistance genes.

We first observed the phenomenon of small colony variants (SCVs) in a Staphylococcus pseudintermedius sequence type 71 (ST71) strain, isolated from a non-pet owner. Although we found that small-sized colonies share main features with Staphylococcus aureus SCVs, they nevertheless show a novel, particular, and sticky phenotype, whose expression was extremely stable, even after subcultivation.

Carbapenem resistance in multidrug-resistant Acinetobacter baumannii has been challenging human medicine ([1][1], [2][2]) and has also emerged in Acinetobacter spp. from animals; it is associated with the expression of OXA-23 in cattle and horses and NDM-1 in a porcine isolate ([3][3][–][4][5][5

Genetic characterization of methicillin-resistant Staphylococcus pseudintermedius (MRSP) from Thailand and Israel revealed the presence of a predominant atypical clonal lineage which was not typeable by SmaI-PFGE and SCC mec typing. All the atypical isolates ( n = 34) belonged to CC45 (30 ST45 and 2 ST179 isolates, 1 ST57 isolate, and 1 ST85 isolate). The isolates originated from healthy and diseased dogs and cats, as well as from the environment of one clinic. Cfr9I–pulsed-field gel electrophoresis (Cfr9I-PFGE) and dru typing permitted the further distinction of CC45 isolates from the two different countries. Microarray analysis identified genes that confer resistance to β-lactams ( mecA ; blaZ ), aminoglycosides [ aac(6′)-Ie–aph(2′)-Ia ; aph(3′)-III ; ant(6)-Ia ], macrolides and lincosamides [ erm (B)], tetracyclines [ tet (M)], trimethoprim [ dfr (G)], streptothricin ( sat4 ), and chloramphenicol ( cat pC221 ). Fluoroquinolone resistance was attributed to specific amino acid substitutions, i.e., Ser84Leu in GyrA and Ser80Ile and Asp84Asn in GrlA. A novel pseudo-staphylococcal cassette chromosome (ΨSCC mec 57395 ) element was identified in MRSP strain 57395 (sequence type ST45) by whole-genome sequencing. The 12,282-bp ΨSCC mec 57395 element contained a class C1 mec gene complex but no ccr genes. In addition to the methicillin resistance gene mecA , ΨSCC mec 57395 also carried determinants of resistance to heavy metals, such as arsenic, cadmium, and copper. Bsu36I restriction analysis of the ΨSCC mec 57395 element amplified by long-range PCR revealed the presence of ΨSCC mec 57395 in the 33 additional isolates of MRSP CC45. The ΨSCC mec 57395 element represents a new class of SCC mec and has been identified in MRSP of CC45, which is a predominant clonal lineage in Israel and Thailand.

Bovine mastitis, an inflammatory disease of the mammary gland, is one of the most costly diseases affecting the dairy industry. The treatment and prevention of this disease is linked heavily to the use of antibiotics in agriculture and early detection of the primary pathogen is essential to control the disease. Milk samples (n=67) from cows suffering from mastitis were analyzed for the presence of pathogens using PCR electrospray-ionization mass spectrometry (PCR/ESI-MS) and were compared with standard culture diagnostic methods. Concurrent identification of the primary mastitis pathogens was obtained for 64% of the tested milk samples, whereas divergent results were obtained for 27% of the samples. The PCR/ESI-MS failed to identify some of the primary pathogens in 18% of the samples, but identified other pathogens as well as microorganisms in samples that were negative by culture. The PCR/ESI-MS identified bacteria to the species level as well as yeasts and molds in samples that contained a mixed bacterial culture (9%). The sensitivity of the PCR/ESI-MS for the most common pathogens ranged from 57.1 to 100% and the specificity ranged from 69.8 to 100% using culture as gold standard. The PCR/ESI-MS also revealed the presence of the methicillin-resistant gene mecA in 16.2% of the milk samples, which correlated with the simultaneous detection of staphylococci including Staphylococcus aureus. We demonstrated that PCR/ESI-MS, a more rapid diagnostic platform compared with bacterial culture, has the significant potential to serve as an important screening method in the diagnosis of bovine clinical mastitis and has the capacity to be used in infection control programs for both subclinical and clinical disease.

A total of 70 Staphylococcus aureus isolates from postoperative infections in hospitalized horses were isolated between January 2005 and January 2011. Among them, 12 isolates were methicillin-susceptible S. aureus (MSSA), 18 were borderline-oxacillin-resistant S. aureus (BORSA), and 40 were methicillin-resistant S. aureus (MRSA). During the same period, the equine clinic personnel were screened for nasal carriage of BORSA and MRSA. Genotyping revealed that BORSA ST1(MLST)-t2863(spa) isolates were responsible for most equine infections and were the main isolates found in colonized members of the personnel between 2005 and 2007, and that in 2007, MRSA ST398-t011-IVa(SCCmec) emerged in infection sites and personnel, replacing BORSA. Besides decreased susceptibility to oxacillin, all MRSA and BORSA of these two major clonal lineages displayed resistance to gentamicin and kanamycin conferred by the aac(6')-Ie-aph(2')-Ia gene and to trimethoprim conferred by dfr(K) in MRSA and dfr(A) in BORSA. All MRSA had additional resistance to tetracycline conferred by tet(M), whereas BORSA generally also display resistance to streptomycin conferred by str. The number of hospital-acquired MRSA infections in horses could be limited after the introduction of basic hygiene measures and personnel decolonization. Two MRSA carriers could not be decolonized using mupirocin, and a year after decolonization, additional members were recolonized with MRSA. Hygiene measures should, therefore, be maintained to limit the transmission of S. aureus between personnel and horses.

OBJECTIVES: We investigated whether Acinetobacter baumannii isolates of veterinary origin shared common molecular characteristics with those described in humans. METHODS: Nineteen A. baumannii isolates collected in pets and horses were analysed. Clonality was studied using repetitive extragenic palindromic PCR (rep-PCR) and multilocus sequence typing (MLST). PCR and DNA sequencing for various beta-lactamase, aminoglycoside-modifying enzyme, gyrA and parC, ISAba1 and IS1133, adeR and adeS of the AdeABC efflux pump, carO porin and class 1/2/3 integron genes were performed. RESULTS: Two main clones [A (n = 8) and B (n = 9)] were observed by rep-PCR. MLST indicated that clone A contained isolates of sequence type (ST) ST12 (international clone II) and clone B contained isolates of ST15 (international clone I). Two isolates of ST10 and ST20 were also noted. Seventeen isolates were resistant to gentamicin, 12 to ciprofloxacin and 3 to carbapenems. Isolates of ST12 carried bla(OXA-66), bla(ADC-25), bla(TEM-1), aacC2 and IS1133. Strains of ST15 possessed bla(OXA-69), bla(ADC-11), bla(TEM-1) and a class 1 integron carrying aacC1 and aadA1. ISAba1 was found upstream of bla(ADC) (one ST10 and one ST12) and/or bla(OXA-66) (seven ST12). Twelve isolates of different STs contained the substitutions Ser83Leu in GyrA and Ser80Leu or Glu84Lys in ParC. Significant disruptions of CarO porin and overexpressed efflux pumps were not observed. The majority of infections were hospital acquired and in animals with predisposing conditions for infection. CONCLUSIONS: STs and the molecular background of resistance observed in our collection have been frequently described in A. baumannii detected in human patients. Animals should be considered as a potential reservoir of multidrug-resistant A. baumannii.

Bacterial infections present a major challenge in equine medicine. Therapy should be based on bacteriological diagnosis to successfully minimize the increasing number of infections caused by multidrug-resistant bacteria. The present study is a retrospective analysis of bacteriological results from purulent infections in horses admitted at the University Equine Clinic of Bern from 2004 to 2008. From 378 samples analyzed, 557 isolates were identified, of which Staphylococcus aureus, Streptococcus equi subsp. zooepidemicus and coliforms were the most common. Special attention was paid to infections with methicillin-resistant S. aureus (MRSA) ST398 and a non-MRSA, multidrug-resistant S. aureus clone ST1 (BERN100). Screening of newly-admitted horses showed that 2.2 % were carriers of MRSA. Consequent hygiene measures taken at the Clinic helped to overcome a MRSA outbreak and decrease the number of MRSA infections.

Fluoroquinolone- and methicillin-resistant Staphylococcus pseudintermedius isolates harbor two new staphylococcal cassette chromosome mec (SCC mec ) elements that belong to class A, allotype 3 (SCC mec II-III), and to the new allotype 5 (SCC mec VII). Analysis of the complete nucleotide sequences of the topoisomerase loci gyrB / gyrA and grlB / grlA revealed mutations involved in fluoroquinolone resistance.

A total of 72 Lactococcus strains (41 Lactococcus lactis and 31 Lactococcus garvieae) isolated from bovine milk were tested for susceptibility to 17 antibiotics and screened for the presence of antibiotic resistance genes using a microarray. Resistance to tetracycline, clindamycin, erythromycin, streptomycin, nitrofurantoin were found. The tetracycline-resistant L. garvieae and L. lactis harbored tet(M) and tet(S). L. lactis that were resistant to clindamycin were also resistant to erythromycin and possessed the erm(B) gene. The multidrug transporter mdt(A), originally described in L. lactis, was detected for the first time in L. garvieae and does not confer decreased susceptibility to erythromycin nor tetracycline in this species. Mdt(A) of L. garvieae contains one mutation in each antiporter motif C, which is known to play an essential role in drug efflux antiporters. This suggests that the mutations found in the C-motifs of Mdt(A) from L. garvieae may be responsible for susceptibility. The study revealed the presence of antibiotic resistance genes in non-pathogenic and pathogenic lactococci from bovine milk, including a mutated multidrug transporter in L. garvieae.

Because of the frequency of multiple antibiotic resistance, Staphylococcus species often represent a challenge in incisional infections of horses undergoing colic surgery. To investigate the evolution of antibiotic resistance patterns before and after preventative peri- and postoperative penicillin treatment, staphylococci were isolated from skin and wound samples at different times during hospitalization. Most staphylococci were normal skin commensals and belonged to the common coagulase-negative group. In some cases they turned out to be opportunistic pathogens present in wound infections. MICs were determined for 12 antibiotics, and antibiotic resistance genes were detected by microarray. At hospital admission, horses harbored staphylococci that were susceptible to antibiotics or resistant to one group of drugs, mainly due to the presence of new variants of the methicillin and macrolide resistance genes mecA and mph (C), respectively. After 3 days, the percentage of Staphylococcus isolates displaying antibiotic resistance, as well as the number of resistance genes per isolate, increased moderately in hospitalized horses without surgery or penicillin treatment but dramatically in hospitalized horses after colic surgery as well as penicillin treatment. Staphylococcus species displaying multiple resistance were found to harbor mainly genes conferring resistance to β-lactams ( mecA and blaZ ), aminoglycosides [ str and aac(6 ′ )-Ie-aph(2 ′ )-Ia ], and trimethoprim [ dfr (A) and dfr (D)]. Additional genes conferring resistance to macrolides [ mph (C), erm (C), and erm (B)], tetracycline [ tet (K) and tet (M)], chloramphenicol [ cat (pC221) and cat (pC223)], and streptothricin ( sat4 ) appeared in several strains. Hospitalization and preventive penicillin use were shown to act as selection agents for multidrug-resistant commensal staphylococcal flora.

A total of 83 Actinobacillus pleuropneumoniae and 58 Actinobacillus porcitonsillarum strains collected from slaughtered pigs in Switzerland were screened for susceptibility to 20 antimicrobial agents by MIC determinations. Resistance to sulfamethoxazole, the combination sulfamethoxazole-trimethoprim, tiamulin, tilmicosin, tetracycline, penicillin and ampicillin were found. A few A. porcitonsillarum isolates displayed decreased susceptibility to enrofloxacin. PCR analysis revealed the presence of the sul2 gene in approximately one-fifth of the sulfonamide-resistant A. pleuropneumoniae and A. porcitonsillarum isolates. The tetracycline-resistant A. pleuropneumoniae harbored tet(B) and tet(H), whereas the tetracycline-resistant A. porcitonsillarum isolates harbored the tet(B) gene. The penicillin and ampicillin-resistant A. pleuropneumoniae and A. porcitonsillarum harbored the bla(ROB-1) gene.

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 ß-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.