Survey of marbofloxacin susceptibility of bacteria isolated from cattle with respiratory disease and mastitis in Europe

Abstract

A monitoring programme conducted in Europe since 1994 to survey the marbofloxacin susceptibility of bacterial pathogens isolated from cattle has established the susceptibility of bacterial strains isolated before any antibiotic treatment from bovine mastitis and bovine respiratory disease (BRD) cases between 2002 and 2008. Minimum inhibitory concentration (MIC) was determined by a standardised microdilution technique. For respiratory pathogens, Pasteurella multocida and Mannheimia haemolytica isolates (751 and 514 strains, respectively) were highly susceptible to marbofloxacin (MIC≤0.03 μg/ml for 77.39 per cent of the strains) and only 1.75 per cent of M haemolytica strains were resistant (MIC≥4 μg/ml). Histophilus somni isolates (73 strains) were highly susceptible to marbofloxacin (0.008 to 0.06 μg/ml). Mycoplasma bovis MIC (171 strains) ranged from 0.5 to 4 μg/ml. For mastitis pathogens, the majority of Escherichia coli isolates were highly susceptible to marbofloxacin (95.8 per cent of 617 strains). Staphylococcus aureus and coagulase-negative staphylococci (568 and 280 strains) had a homogenous population with MIC centred on 0.25 μg/ml. Streptococcus uberis and Streptococcus dysgalactiae (660 and 217 strains) were moderately susceptible with MIC centred on 1 μg/ml. Marbofloxacin MIC for these various pathogens appeared stable over the seven years of the monitoring programme and was similar to previously published MIC results.

Survey of susceptibility to marbofloxacin in bacteria isolated from diseased pigs in Europe

“…Marbofloxacin-resistant strains were determined as having a marbofloxacin MIC≥4 μg/ml, strains that had a marbofloxacin MIC=2 μg/ml were considered as intermediate and susceptible strains had a marbofloxacin MIC≤1 μg/ml. These breakpoints have been used previously in the analysis of marbofloxacin susceptibility in cattle (Meunier and others 2004a, Kroemer and others 2012) and cats and dogs (Meunier and others 2004b, Kroemer and others 2014) and also by the French monitoring programme on antibioresistance in animals (RESAPATH 2015). …”

“…Since 1994 Vétoquinol S.A. has run a surveillance programme in Europe to monitor the marbofloxacin susceptibility of bacteria from bovine, feline, canine and porcine diseases. Some initial reports for marbofloxacin have been published for pathogens from bovine infections (Meunier and others 2004a, Kroemer and others 2012) and infections from cats and dogs (Meunier and others 2004b, Kroemer and others 2014). In this study, the authors present susceptibility data for marbofloxacin against pathogens isolated from pigs in Europe between 1994 and 2013.…”

Alterations in the Quinolone Resistance-Determining Regions and Fluoroquinolone Resistance in Clinical Isolates and Laboratory-Derived Mutants of Mycoplasma bovis: Not All Genotypes May Be Equal

“…Most often, a low level of resistance to fluoroquinolones, associated with a narrow MIC distribution in the range of 0.25 to 4 g/ml, is considered to represent a single homogeneous population of isolates (6). However, in the French M. bovis population, the MIC distribution of enrofloxacin, in the range of 0.125 to 1 g/ml, was previously shown to be bimodal, with a very moderate shift of MICs between old and recent isolates (5).…”

“…With regard to fluoroquinolones, the decrease in susceptibility was limited (only 1 dilution of the MIC), and no highly resistant isolates were observed in a set of more than 90 strains. This was unexpected, since one of the two major medical indications of injectable extendedspectrum fluoroquinolones for cattle is BRD (6). However, in contrast to other antimicrobials, such as tulathromycin, tilmicosin, ceftiofur, and florfenicol, expanded-spectrum fluoroquinolones are not approved for metaphylaxis or prevention in herds (2,7).…”

“…Three studies reported highly resistant isolates, with MICs of Ͼ8 g/ml, in the United Kingdom, Japan, and Belgium (9-11), while several others indicated a low to no increase in resistance, except for a few isolates, in Japan, the United States, and several European countries (6,(12)(13)(14)(15). Some of these studies involved isolates collected before 2005 (11, 13), but the majority referred to recent ones (6,9,10,12,14,15), suggesting a recent phenomenon. In the United Kingdom, a shift of resistance from an MIC 90 of 1 g/ml to one of 32 g/ml occurred during the last decade (9, 16).…”