Efficacy of Fosfomycin on <i>Escherichia coli</i> Isolated from Bitches with Pyometra

Abstract

ABSTRACT. The aim of this study was to determine the antimicrobial resistance of Escherichia coli isolated from the uteri of bitches with pyometra, and 38 E. coli isolates were used. The antimicrobials used were ampicillin (ABPC), amoxicillin/clavulanic acid, gentamicin, minocycline, cefazolin, levofloxacin (LVFX), trimethoprim-sulfamethoxazole (ST) and fosfomycin (FOM). Resistance to ABPC occurred most frequently, followed by LVFX and ST. Multi-drug resistance, defined as resistance against 3 or more classes of antimicrobials, was found in 23.7% of all isolates. Nine out of 13 resistant strains were multi-drug resistant, but no strain was found to be resistant to FOM. This suggests that FOM should be administered for E. coli from pyometra. KEY WORDS: antimicrobial resistance, bitch, Escherichia coli, fosfomycin, pyometra.doi: 10.1292/jvms.12-0489; J. Vet. Med. Sci. 75(5): 657-658, 2013 Pyometra is regarded as one of the most common illnesses in bitches [10,16,18]. Its etiology and pathogenesis are complex and only partly understood [11,14,16,17,19]. The most common bacterium isolated in cases of pyometra is Escherichia coli(E. coli) [1,5,8,11,16]. There have been a few studies of resistance to antimicrobials among bacteria isolated from the uteri of bitches with pyometra [4,7,9,15,20]. The resistant ratio of E. coli isolated from pyometra is reported to be various, but is mostly lower than urine samples [9,18].Fosfomycin is a cell-wall-active antimicrobial, classified as bactericidal in action, with a broad spectrum including Gram-negative and Gram-positive organisms [3,13]. Hubka and Boothe suggested that fosfomycin shows effective antimicrobial activity against E. coli associated with spontaneous disease in dogs and cats, including isolates expressing multi-drug resistant isolates cultured from the urinary tract [12].The aim of this study was to determine the antimicrobial resistance of E. coli isolated from the uteri of bitches with pyometra.Samples were taken from 38 bitches that underwent ovariohysterectomy, because of pyometra at Fukuda Animal Hospital (Osaka, Japan) between April 2009 and the end of March 2012. Each sample from a uterus suffering from pyometra was plated onto desoxycholate-hydrogen sulfidelactose (DHL) agar (Eiken Chemical Co., Ltd., Tokyo, Japan). After incubation at 37°C for 18 hr, two to four red colonies were identified using miniaturized biochemical systems (API System; bioMerieux, Lion, France). One strain was selected from 2 to 4 colonies with the same biological properties. As a result, 38 E. coli isolates were obtained from the uterus. E. coli isolates were stored in MicroBANK (ProLab Diagnostic, Richmond Hill, ON, Canada) at −80°C until further use.Susceptibility to each of 8 antimicrobials was determined using the agar dilution method according to the guidelines of the Clinical and Laboratory Standard Institute (CLSI 2010) [2]. The antimicrobials used were ampicillin (ABPC), amoxicillin/clavulanic acid (CVA-AMPC), gentamicin (GM), minocycline (MINO), cefazolin (CEZ), levofl...

Escherichia coliStrains Isolated from the Uteri Horn, Mouth, and Rectum of Bitches Suffering from Pyometra: Virulence Factors, Antimicrobial Susceptibilities, and Clonal Relationships among Strains

“…The highest resistance among the E. coli pyometra isolates in this study was to cephalothin and ampicillin agreeing with Coggan et al [11] but higher than the results reported by Siqueira et al [12] and Inoue et al [13] to ampicillin. Also the results reported to ciprofloxacin, norfloxacin, and gentamicin sensitivity agree with those reported by Siqueira et al [12], Coggan et al [11], and Inoue et al [13]. …”

“…The antimicrobial resistances in strains of E. coli from pyometra have been reported by several authors [11–13]. The highest resistance among the E. coli pyometra isolates in this study was to cephalothin and ampicillin agreeing with Coggan et al [11] but higher than the results reported by Siqueira et al [12] and Inoue et al [13] to ampicillin.…”

“…Already, several studies suggest a possible exchange of resistant organisms and/or their resistance genes between humans and their pets [9, 10]. There have been a few studies of resistance to antimicrobials among bacteria isolated from the uteri of bitches with pyometra [11–13]. …”

Perfil de sensibilidade antimicrobiana de bactérias isoladas, de piometra em cadelas, frente a gentamicina de infusão uterina (Gentrin®)

“…Agostinho (2014) em seu estudo chama a atenção severamente para a estreita relação entre os cães e humanos, e trabalha com a resistência dessa bactéria isolada em piometra, e fatores de risco para o homem (Van Den Bogaard & Stobberingh, 2000;Guardabassi, et al, 2004). A resistência de cepas de E. coli isoladas de piometra já foi relatada por diversos autores (Coggan, et al, 2008;Carlos, et al, 2012;Huber, et al, 2013;Inoue, et al, 2013).…”

“…Foram demonstradas que cepas de E. coli isoladas das fezes como também de piometra, já apresentaram multirresistências em estudos anteriores para cefalotina, ampicilina, ciprofloxacina, norfloxacina e gentamicina, como descrito por Coggan et al (2008), Siqueira et al (2008), Inoue et al (2013), como também foi apresentado nas duas concentrações mais baixas de diluições de Gentrin® no presente estudo.…”