________________________________________________________________________________________ PINTARIĆ, S., K. MATANOVIĆ, B. ŠEOL MARTINEC:Fluoroquinolone susceptibility in Pseudomonas aeruginosa isolates from dogs -comparing disk diffusion and microdilution methods. Vet. arhiv 87, 291-300, 2017. ABSTRACTPseudomonas aeruginosa has been determined to be the distinct cause of a number of different infections in both humans and animals. Apart from its high intrinsic resistance, which makes it difficult to treat, it also has a great capacity to acquire further resistance mechanisms. These mechanisms can be present simultaneously in one cell, conferring a multiresistant phenotype. Taking into account that the known risk factor for selection of resistant strains is excessive and inappropriate drug use, especially fluoroquinolones, the aim of this study was to determine the susceptibility of P. aeruginosa isolates to these antibacterial agents. The susceptibility of 90 canine isolates was determined by disk diffusion susceptibility test and the broth microdilution method. Both methods showed that isolates were significantly more sensitive to ciprofloxacin than to marbofloxacin or enrofloxacin, and more sensitive to marbofloxacin than to enrofloxacin. The results of microdilution and disk diffusion testing were in 98.9% agreement for ciprofloxacin and in 91.1% agreement for marbofloxacin, with no statistically significant difference between the two methods (P>0.05) for these two antibiotics. For enrofloxacin, the results of microdilution and disk diffusion testing were in 76.6% agreement, with a statistically significant disagreement between the two methods (P<0.05). In 16 cases, the disk diffusion test overestimated the number of strains susceptible to enrofloxacin compared with the microdilution test. These results suggest that for P. aeruginosa infections in dogs, therapy using enrofloxacin, based on the results of disk diffusion testing, may lead to ineffective treatment and could contribute to selection of resistant and multiresistant strains.

The genetic analysis of high-level mupirocin resistance (Hi-Mup r ) in a Staphylococcus pseudintermedius isolate from a dog is presented. The Hi-Mup r ileS2 gene flanked by a novel rearrangement of directly repeated insertion sequence IS257 elements was located, together with the aminoglycoside resistance aacA-aphD determinant, on a conjugative plasmid related to the pSK41/ pGO1 family plasmids.

Bakterijske su infekcije urinarnog trakta (IUT) u pasa učestale. Porast antimikrobne rezistencije i uporaba kritično-važnih antimikrobnih lijekova, osobito u liječenju IUT pasa, zabrinjavajuća je zbog pojave multiplo rezistentnih bakterijskih sojeva. Cilj je ovog rada bio prikazati prevalenciju i antimikrobnu resistenciju najčešćih bakterijskih uzročnika IUT pasa i trendove antimikrobne rezistencije izdvojenih bakterijskih sojeva u Republici Hrvatskoj tijekom 11 godina. Od ukupno 2721 pretraženih uzoraka urina, potitivno je bilo 1363 (50,1 %). Bakterijska vrsta Escherichia coli bila je najčešće izdvojeni mikroorganizam (47,3 %), nakon čega slijede: koagulaza pozitivni Staphylococcus sp. (20,7 %), Proteus sp. (14,7 %), Enterococcus sp. (13,6 %), beta hemolitični Streptococcus sp. (11,7 %), Pseudomonas aeruginosa (4,5 %) i meticilin rezistentni koagulaza pozitivni Staphylococcus sp. (3,4 %). Kod Gram-negativnih bakterija uočen je visok stupanj osjetljivosti na: gentamicin, amikacin (77,9 %-97,3 %), marbofloksacin i ciprofloksacin (69,7 %-98,4 %). Kod bakterijskog roda Proteus utvrđen je i visok stupanj osjetljivosti na beta-laktame (70,5 %-86,7 %), a kod Escherichia coli i na kloramfenikol (73,3 %) i trimetoprim/sulfametoksazol (72,7 %). Neznatan postotak koagulaza pozitivnih Staphylococcus sp. bila je osjetljiva na penicilin (10,6 %) i ampicilin (16,7 %), dok je mala osjetljivost zamijećena na streptomicin, neomicin i tetracikline (56,0 %-66,0 %). Najmanji postotak beta hemolitičnih Streptococcus sp. bio je osjetljiv na aminoglikozide, tetracikline (8,2 %-31,9 %) i fluorokinolone (31,5 %-61,6 %). Kod bakterijskih izolata Enterococcus sp. najveća osjetljivost prisutna je na amoksicilin/klavulansku kiselinu (78,0 %) i ampicilin (70,4 %). Amikacin i kloramfenikol, s postotkom osjetljivosti od 89,3 %, odnosno 80,9 %, bili su jedini antimikrobni lijekovi učinkoviti na meticilin rezistentne koagulaza pozitivne Staphylococcus sp. Tijekom 11 godina istraživanja zamijećen je trend porasta antimikrobne rezistencije bakterija Escherichia coli i Proteus sp., izdvojenih iz IUT pasa, na fluorokinolone, ampicilin i amoksicilin/klavulansku kiselinu, dok je kod bakterijske vrste Escherichia coli uočen porast antimikrobne rezistencije i na cefalosporine. Ovi rezultati će pomoći pri empirijskom odabiru antimikrobnih lijekova za terapiju IUT pasa te podizanju svijesti o razumnoj uporabi antimikrobnih lijekova.

The physiological properties of 47 Staphylococcus aureus strains were investigated. The test strains were grown on bacteriological media and identified by the ID32 STAF system for biochemical identification of bacteria. Sensitivity to antimicrobial agents was performed by the disc diffusion method. The nuc gene and the virulence factors coa, hla, hlb, hld, hlg, hlg-2, tst, eta, etb, lukF-PV and lukS-PV and mecA gene were detected by the polymerase chain reaction. Furthermore, the spa type of the studied isolates was also set. According to the obtained results, all strains had the nuc, coa, hla and hld gene. Ten strains (21.3 %) had also the tst gene, while 37 strains (78.7 %) had the hlg gene and 35 strains (74.5 %) had the hlb and hlg-2 genes. All of the investigated S. aureus isolates were penicillin resistant (100 %), with 29 strains which were also resistant to oxacillin (61.7 %). Methicillin (oxacillin) resistance was detected by the mecA gene detection, which is also the first MRSA result from the secretion samples of cows’ mammary glands in Croatia. The researched MRSA strains proved to belong to different spa types, and the most common were spa types t005, t011 and t521, and a new spa type t9498 was detected.

The consequences of infection by Suid herpesvirus type 1 (SuHV-1) that causes Aujeszky’s disease (AD) are well studied, however, the effects of immunomodulators (IMs) of microbial origin (viral and bacterial) when administered solely or in combination with the attenuated SuHV-1 vaccine are less known. The effects of parenteral administration of IMs, inactivated Parapoxvirus ovis (P. ovis) or a combination of inactivated Propionibacterium granulosum (P. granulosum) and detoxified Escherichia coli lipopolysaccharide (LPS) and attenuated SuHV-1, strain Bartha, on the proportion of peripheral blood CD3- CD21+ B cells were analysed in 30 crossbred, 3-month old pigs using flow cytometry (FCM). Specific antibodies for gE and gB of SuHV- 1 were detected using the enzyme-linked immunosorbent assay (ELISA). Data were compared among six experimental groups: (1) pigs that separately received the vaccine, (2) IM of bacterial origin, (3) IM of viral origin, (4) simultaneous administration of the vaccine and bacterial IM, (5) simultaneous administration of the vaccine and viral IM, and (6) the control group of untreated pigs. Comparison of B cell proportions and the detection of specific antibodies in blood samples of vaccinated pigs on Day 11 of the experiment showed a transient decrease in B cell contents, though this could not be assumed to be related since the control group showed a decrease in B cell proportion on the same day. The results showed that the use of IMs alone or in combination with the attenuated SuHV-1 vaccine did not have a significant impact on the proportion of peripheral blood B cells in growing pigs.