Antimicrobial susceptibility of Enterococcus strains isolated from poultry faeces

We have investigated the resistance of Enterococcus isolated from poultry faeces to antibiotics commonly used as therapy of enterococcal infections. Identification was made by the method of Facklam and Collins. Minimal inhibitory concentrations of penicillin, ampicillin, vancomycin and teicoplanin were determined and high level aminoglycoside resistance was investigated. Genes codifying high level aminoglycoside resistance (HLAR) were determined by PCR. Fifty five Enterococcus strains were isolated (63.6% E. faecalis, 12.7% E. mundtii, 9.1% E. faecium, 7.3% E. casseliflavus, 3.7% E. durans and 3.6% E. hirae). None of the strains were resistant to VAN, TEC, P or AM. HLAR was found in 34.5% of strains for SM, 27.3% for KM and 7.3% for GM. The gene for the bifunctional enzyme was found only in one strain, that showed HLAR to GM and KM. Fourteen strains harboured the gene aph(3')-III, being 11 resistant to KM and STR, and three resistant to GM, KM and STR. The remaining six strains showed HLAR to STR, but were negative for the three genes tested by PCR. The gene ant(4'4") was not detected in any of the strains. No unexpected vancomycin resistance was detected. The resistance rates among poultry strains were lower than those found among human strains isolated from hospital patients in recent Canary studies.     

Antimicrobial susceptibility of Staphylococcus intermedius and Staphylococcus schleiferi isolated from dogs

The susceptibility to 23 antimicrobial agents was determined in 114 isolates of Staphylococcus intermedius and eight isolates of Staphylococcus schleiferi of canine origin. Overall, 73% of S. intermedius isolates and 37.5% of S. schleiferi isolates were susceptible to all the 23 antimicrobials tested. The large majority of S. intermedius strains retained susceptibility to antimicrobials currently employed in treatment of pyoderma (cephalosporins, cotrimoxazole and association amoxicillin–clavulanic acid) as well as to those effective against staphylococci (fusidic acid, rifampicin and fluoroquinolones). Resistance in S. intermedius was observed mainly against macrolides, chloramphenicol and lincosamides, while S. schleiferi isolates retained susceptibility to all antimicrobials except three of six fluoroquinolones. Although, our results confirm susceptibility to antimicrobials currently employed in pyoderma treatment, the several different resistance patterns observed for S. intermedius emphasize the importance of antimicrobial susceptibility testing of canine staphylococci to choose the most appropriate treatment of infections and to allow the prudent use of antimicrobial drugs in companion animals.     

Antimicrobial susceptibility of porcine Brachyspira hyodysenteriae and Brachyspira pilosicoli isolated in Sweden between 1990 and 2010

Background

The anaerobic spirochetes Brachyspira hyodysenteriae and Brachyspira pilosicoli cause diarrheal diseases in pigs. Their fastidious nature has hampered standardization of methods for antimicrobial susceptibility testing. For monitoring of antimicrobial susceptibility wild type cutoff values are needed to define where the wild type distribution of MICs ends and no approved cutoffs are available for Brachyspira spp. In this study antimicrobial susceptibility data for both species (in total 906 isolates) were compiled and analyzed and wild type cut off values for B. hyodysenteriae proposed.

Methods

The MICs of tiamulin, valnemulin, tylosin, tylvalosin, doxycycline and lincomycin were determined by broth dilution in brain heart infusion broth supplemented with 10% fetal calf serum.

Results

The compiled MICs from the broth dilution tests of the B. hyodysenteriae type strain, B78^T (ATCC® 27164^T), showed that the method yields reproducible results. In an international perspective the frequencies of isolates with decreased antimicrobial susceptibility were low among both B. hyodysenteriae and B. pilosicoli. However, in B. pilosicoli a constant level of 10-15% isolates with tiamulin MICs >4 μg/ml was detected between 2002 and 2010 and in B. hyodysenteriae a gradual increase in tiamulin MICs was seen between 1990 and 2003 although this increase has ceased during the last years. The wild type cutoff values proposed for B. hyodysenteriae are: tiamulin >0.25 μg/ml, valnemulin >0.125 μg/ml, tylosin >16 μg/ml, tylvalosin >1 μg/ml, lincomycin >1 μg/ml and doxycycline >0.5 μg/ml.

Conclusions

The broth dilution method used in this study has over the years generated tightly grouped MIC populations for the field isolates and reproducible results for the control strain B78^T and is therefore a suitable antimicrobial susceptibility test method for monitoring of Brachyspira spp. Here we propose wild type cutoff values for six antimicrobial agents for B. hyodysenteriae tested by broth dilution based on MIC distributions and the current knowledge on mechanisms of resistance in this species. There are few studies on antimicrobial resistance mechanisms and MIC distributions in B. pilosicoli but to some extent the cutoff values proposed for B. hyodysenteriae may be applicable also for monitoring of antimicrobial susceptibility in B. pilosicoli.     

The anatomical distribution and antimicrobial susceptibility of yeast species isolated from healthy dogs

The aim of this work was to identify the predominant yeast species present at different anatomical sites in healthy dogs and to determine their in vitro antimicrobial susceptibility using a broth microdilution assay. Samples were collected from the preputial, vaginal, oral and perianal mucosae and the isolates cultured were identified according to their morphological characteristics and biochemical profile. Malassezia pachydermatis was the most commonly isolated yeast, followed by Candida parapsilosis, Candida tropicalis, Candida albicans, Saccharomyces cerevisiae and Rhodotorula spp.Minimum inhibitory concentrations of the azole derivatives ketoconazole, itraconazole and fluconazole against Candida spp. were 0.03–16 μg/mL, 0.06 to >16 μg/mL and 0.5–64 μg/mL, respectively and Candida isolates were sensitive to caspofungin and amphotericin B. Although all isolates of M. pachydermatis were sensitive to itraconazole, fluconazole, ketoconazole and amphotericin B, they were found to be resistant to caspofungin. The study has highlighted that Candida spp., M. pachydermatis, S. cerevisiae and Rhodotorula spp. are part of the normal canine surface microbiota and some of these organisms exhibit in vitro resistance to commonly used antimicrobials.     

Antimicrobial susceptibility testing of Spanish field isolates of Brachyspira hyodysenteriae

This study is the first conducted in Spain to evaluate antimicrobial susceptibility of field isolates of Brachyspira hyodysenteriae. One hundred and eight isolates of the bacterium, recovered from different Spanish swine farms between 2000 and 2007, were investigated. The minimum inhibitory concentrations (MIC) of erythromycin, tylosin, tiamulin, valnemulin, clindamycin and lincomycin were determined using a broth microdilution technique. Most of the isolates showed poor susceptibility to erythromycin (MIC₉₀ > 256 μg/ml), tylosin (MIC₉₀ > 256 μg/ml), clindamycin (MIC₉₀ > 4 μg/ml) and lincomycin (MIC₉₀ = 128 μg/ml). Reduced susceptibility to tiamulin and valnemulin was observed with a MIC > 2 μg/ml in 17.6% and 7.41% of the B. hyodysenteriae isolates, respectively. Moreover, a survival analysis permitted the detection of an increasing trend in the MIC values for almost all the antimicrobials used in the treatment of swine dysentery when comparing recent isolates (from 2006 to 2007) with those recovered in earlier years (between 2000 and 2004).     

Antimicrobial resistance pattern of Salmonella serotypes isolated from food items and personnel in Addis Ababa, Ethiopia

Antimicrobial susceptibility test of 98 isolates of Salmonella was assayed from September 2003 to February 2004 using the guidelines of the National Committee for Clinical Laboratory Standards (NCCLS).The result revealed that 32.7% of Salmonella isolates were resistant to one or more of the 24 antimicrobials tested. Generally resistance for 13 different antimicrobial drugs was recognized. The most common resistance was to streptomycin (24/32, 75%), ampicillin (19/32, 59.4%), tetracycline (15/32, 46.9%), spectinomycin (13/32, 40.6%) and sulfisoxazole (13/32, 40.6%). All the three Salmonella Kentucky isolates showed resistance to at least 8 antimicrobials. Out of the 12 Salmonella Braenderup isolates, 10 (83.3%) showed multidrug resistance to ampicillin, spectinomycin, streptomycin, sulfisoxazole, sulfamethoxazole/trimethoprim, amoxicillin/clavulanic acid and trimethoprim. Among the 8 S. Hadar isolates 7 (86.5%) showed antimicrobial resistance. All the 6 S. Dublin isolates were resistant to carbadox (100%). All the 6 S. Haifa isolates were resistant for at least ampicillin, streptomycin and tetracycline. Up to ten different antimicrobial resistances pattern was observed. Multiple antimicrobial drug resistance was observed in 23 Salmonella isolates (23.5%). The level of antimicrobial resistance was significantly higher for isolates from chicken carcass (18/29, 62.1%) and pork isolates (5/22, 22.7%) (p = 0.003). The findings of the present study ascertain that significant proportion Salmonella isolates have developed resistance for routinely prescribed antimicrobial drugs and poses considerable health hazards to the consumers unless prudent control measures are instituted.     

Virulence characterization of Campylobacter jejuni isolated from resident wild birds in Tokachi area,Japan

The prevalence of Campylobacter jejuni in wild birds is a potential hazard for human and animal health. The aim of this study was to establish the prevalence of C. jejuni in wild birds in Tokachi area, Hokkaido, Japan and investigate their virulence in vitro. In total, 173 cloacal swabs from individual wild birds were collected for the detection of Campylobacter spp. Thirty four samples (19.7%) were positive for Campylobacter of which 94.1% (32/34 samples) were C. jejuni. Additionally, one C. coli and one C. fetus were isolated. Seven C. jejuni isolates (one from crows and the other from pigeons) had important virulence genes including all three CDT genes (cdtA, cdtB and cdtC) and flaA, flaB, ciaB and cadF, and the other isolates were lacking cdtA gene. Further studies on in vitro virulence-associated phenotypes, such as motility assay on soft agar and invasion assay in Caco-2 cells, were performed. The wild bird C. jejuni isolates adhered and invaded human cells. Although the numbers of viable intracellular bacteria of wild bird isolates were lower than a type strain NCTC11168, they persisted at 48-hr and underwent replication in host cells.     

Prevalence,quantitative load and genetic diversity of Campylobacter spp. in dairy cattle herds in Lithuania

Background

Campylobacteriosis is a zoonotic disease, and animals such as poultry, pigs and cattle may act as reservoirs for Campylobacter spp. Cattle shed Campylobacter spp. into the environment and they can act as a reservoir for human infection directly via contact with cattle or their faeces or indirectly by consumption of contaminated food. The aim of this study was to determine the prevalence, the quantitative load and the genetic strain diversity of Campylobacter spp. in dairy cattle of different age groups.

Results

Faecal samples of 200 dairy cattle from three farms in the central part of Lithuania were collected and examined for Campylobacter. Cattle herds of all three farms were Campylobacter spp. positive, with a prevalence ranging from 75% (farm I), 77.5% (farm II) to 83.3% (farm III). Overall, the highest prevalence was detected in calves (86.5%) and heifers (86.2%). In contrast, the lowest Campylobacter prevalence was detectable in dairy cows (60.6%). C. jejuni, C. coli, C. lari and C. fetus subsp. fetus were identified in faecal samples of dairy cattle. C. upsaliensis was not detectable in any sample. The high counts of Campylobacter spp. were observed in faecal material of dairy cattle (average 4.5 log₁₀ cfu/g). The highest numbers of Campylobacter spp. were found in faecal samples from calves (average 5.3 log₁₀ cfu/g), whereas, faecal samples from cows harboured the lowest number of Campylobacter spp. (average 3.7 log₁₀ cfu/g). Genotyping by flaA PCR-RFLP analysis of selected C. jejuni isolates showed that some genotypes were present in all farms and all age groups. However, farm or age specific genotypes were also identified.

Conclusions

Future studies are needed to investigate risk factors related to the degree of colonisation in cattle. Based on that, possible measures to reduce the colonisation and subsequent shedding of Campylobacter in cattle could be established. It is important to further investigate the epidemiology of Campylobacter in the cattle population in order to assess associated risks to public health.     

Antimicrobial susceptibility and tetracycline resistance determinant genotyping of Gallibacterium anatis

The present investigation was undertaken to assess the antimicrobial susceptibility of a collection of 58 Gallibacterium isolates. All strains were tested by the broth dilution method using the veterinary fastidious medium. A total of 46 field strains were tested, whereof 23 were clinical isolates from 10 Mexican layer flocks and another 23 isolates originated from 13 clinically healthy poultry flocks in Denmark. In addition, 12 Gallibacterium reference strains that had been isolated some 30–40 years ago were included.     

国内外食品源及动物源弯曲菌流行性及耐药性调查研究进展

弯曲菌是重要的食品源性致病微生物,在很多动物中属于正常携带细菌,能通过食物链传递给人类,可引起人类肠炎的暴发流行和食物中毒。在畜牧养殖业大量抗菌药物的使用,造成动物源弯曲菌耐药性日益增加,给人类带来健康风险。发达国家很早就开展了动物源性弯曲菌流行性和耐药性监测工作,很多发展中国家也对弯曲菌流行性和耐药性监测越来越重视,文章将就近年来国内外动物源性弯曲菌的流行及耐药情况调查工作做简单的总结,为中国动物源性弯曲菌流行性和耐药性工作的开展提供比较及理论分析数据。     

Study on Coccidiosis of Scavenging Indigenous Chickens in Central Ethiopia

An investigation was made into coccidiosis of 190 scavenging indigenous chickens between September 2000 and April 2001 in three selected agroclimatic zones, in central Ethiopia. This was done through clinical, postmortem and microscopic examinations. Data were processed by chi-square and Mantel-Haenzel test. The study indicated that 25.8% (49/190) of the chickens were infected with coccidiosis and found to harbour one to four different species of Eimeria. Of these infected chickens, 30 (15.8%) and 19 (10.0%) were positive for clinical and sub-clinical coccidiosis, respectively. There was a significant altitude difference (chi2 = 14.7, p <0.001) in coccidiosis prevalence: 42.2% in chickens from highland region followed by 21.5% in mid-altitude and 13.1% in low-altitude areas. When quantified, the prevalence of coccidiosis was 2.66 and 4.83 times higher in the high-altitude than in mid-altitude (odds ratio, OR = 2.66, p<0.05) and low-altitude (OR = 4.83, p<0.001) chickens. The pathogenic Eimeria species responsible for clinical coccidiosis were E. necatrix, E. acervulina, E. maxima and E. tenella. With increasing demand for poultry products in developing countries, knowledge of production constraints in traditional management practices could help devise control strategies for constraints on backyard poultry production systems.     

Detection and genotypic differentiation of Campylobacter jejuni and Campylobacter coli strains from laying hens by multiplex PCR and fla-typing

In total, 26 Campylobacter (C.) strains, isolated from liver, spleen, caecal or jejunal content of laying hens from different flocks were examined. In these flocks a drop in egg production, an increasing mortality and livers with whitish-grey lesions as post-mortem finding were observed. Suspected Campylobacter colonies were differentiated using a modified m-PCR in 13 Campylobacter jejuni and 13 Campylobacter coli strains. All isolates were characterised by typing of the flaA and flaB gene each with two restriction enzymes. To compare the four different profiles for all strains an artificial “fla-type” was generated. Different and identical fla-types of C. jejuni and C. coli were recovered from both intestinal and extra-intestinal organs of the laying hens and even from individual birds. One significant observation is that some fla-types of C. jejuni or C. coli were detected in intestinal and systemic sites but not all fla-types of both species appeared to be equally able to invade internal organs.     

Prevalence,species distribution and antimicrobial resistance patterns of methicillin-resistant staphylococci in Lithuanian pet animals

Background

The bacterial genus Staphylococcus consists of many species that causes infections in pet animals. Antimicrobial resistant staphylococci cause infections that are difficult to treat and they are important from the point of one health perspective. The aim of this study was to determine the prevalence of methicillin-resistant Staphylococcus (MRS) species, including methicillin-resistant S. aureus (MRSA) in diseased pet animals (Group A) and kennel dogs (Group B) in Lithuania and to characterize the isolates according to their antimicrobial resistance.

Results

Twenty-one MRS isolates were obtained from 395 clinical samples (5.3 %; CI 95 % 3.5-8.0) of Group A animals. Sixteen, four and one isolates were from dogs, cats and a pet rabbit, respectively. The mecA gene was present in 20 isolates, whereas one isolate was positive for the mecC gene. Twenty-one MRS isolates (20.0 %; CI 95 % 13.5-28.6) were obtained from the vagina of female dogs (n = 105) (Group B). All isolates carried the mecA gene. Twelve MRS species were isolated of which S. pseudintermedius was the most common (18/42) followed by S. haemolyticus (8/42) and S. lentus (4/42). MRSA was not found. All MRS strains were susceptible to vancomycin, linezolid, daptomycin and quinupristin/dalfopristin. Resistance to tetracycline (16/21), clindamycin (15/21) and erythromycin (14/21) was the most common types of resistance in Group A animals. Three isolates also demonstrated resistance to rifampin. Resistance toward gentamicin (16/21), ciprofloxacin (15/21), macrolides (15/21) and tetracycline (12/21) was the most common in kennel dogs (Group B). The most common genes encoding resistance to antimicrobials (excluding beta-lactams) in isolates from Group A pets were tetK (21/42), aph(3′)-IIIa (11/42) and aac(6'')-Ie-aph(2'''')-Ia (9/42).

Conclusions

A wide range of MRS species were found in pet animals in Lithuania. MRSA was not found.     

A survey of Salmonella spp and Campylobacter spp in dairy goat faeces and bulk tank milk in the Murcia region of Spain

This study was designed to investigate the occurrence of Salmonella spp and Campylobacter spp in faeces samples from 222 healthy Murciano-Granadina dairy goats reared on 12 farms in Spain and in samples of bulk tank milk from 11 of those herds. Neither Salmonella spp nor Campylobacter spp were isolated from any of the samples. Our results suggest that, under the management practices applied to this breed in Spain, Murciano-Granadina goats are not likely to be a significant reservoir for these food-borne pathogens.     

Biofilm-forming associated genotypic and phenotypic characteristics of Staphylococcus spp. isolated from animals and air

Biological monitoring is performed to detect and analyze microorganisms that have continuously made an effort to survive in the environment. Of such microorganisms, Staphylococcus spp. is considered a common cause of nosocomial and environmental infections., Microbial Surface Components Recognizing Adhesive Matrix Molecules (MSCRAMMs) are required for the adhesion and biofilm formation of Staphylococci. Thirty-six and thirty-five Staphylococci isolated from animals and air, respectively, were analyzed. Biofilm formation and ten MSCRAMM genes were investigated using Congo red agar, tissue culture plate methods, and PCR. Airborne isolates were shown to have higher adherence and stronger biofilm formation than those from animals. The prevalence of MSCRAMM genes from air isolates was also higher than those from animals. Of the genes, eno was mainly associated with biofilm formation in both animals and airborne isolates (P < 0.05). Moreover, the rate of airborne isolates harboring the eno gene was higher than in animal isolates. These results indicated that analysis of MSCRAMM genes with a phenotypic assay might be a helpful bacterial control system for the environment.     

Antimicrobial susceptibility and molecular characterization of macrolide resistance of Mycoplasma bovis isolates from multiple provinces in China

Mycoplasma bovis has spread widely throughout the world via animal movement and has becomean important pathogen of bovine respiratory disease. However, the minimum inhibitory concentrations ofantimicrobials for Mycoplasma bovis have not been studied in China. The objective of thisstudy was to determine the prevalence and antibiotic resistance of Mycoplasma bovis isolatedfrom young cattle with respiratory infection in China. Mycoplasma bovis was detected in 32/45bovine respiratory infection outbreaks at beef farms in 8 provinces in China. The isolates were susceptible orhad medium sensitivity to ciprofloxacin, enrofloxacin and doxycycline, but were frequently resistant tomacrolides (13/32, 41%). An A2058G (Escherichia coli Numbering) mutation located in therrnA operon in domain V of 23S rRNA was observed in strains that were resistant tomacrolides. This single mutations at the rrnA operon in domain V of 23S rRNA may play an important role in theresistance of Mycoplasma bovis strains to macrolides.     

Prevalence and characterization of Staphylococcus aureus and Staphylococcus pseudintermedius isolated from companion animals and environment in the veterinary teaching hospital in Zambia,Africa

The Republic of Zambia consists of only one veterinary teaching school at the University of Zambia (UNZA) where students and veterinarians are exposed to many bacterial pathogens including Staphylococcus aureus (SA) and Staphylococcus pseudintermedius (SP). The aim of this study was the characterization and antimicrobial susceptibility profile of eleven SA and 48 SP isolates from the veterinary hospitals’ in- and outpatients and the environment. No isolate was resistant to cefoxitin by disk diffusion test and the corresponding resistance gene mecA was not found. In contrast, the resistance rates of SA to penicillin (63.6%) and trimethoprim-sulfamethoxazole (36.4%) and SP to penicillin (52.1%) and tetracycline (25.0%) were the highest. A variety of sequence types (STs) without a predominant type including numerous novel types were determined, especially for SP (39.6%). The spa typing provided a clonal assignment for all SAs (100%) and 24 SPs (50%) with three and two novel types, respectively. This study has provided an overview of SA and SP in the veterinary teaching hospital at UNZA. However, for a better understanding of these species regarding pathogenesis and transmission, further studies on the prevalence and characterization of SA and SP from veterinary staff, pet owners, and farm animals in Zambia is needed.     

Prevalence of thermophilic Campylobacter species in Swedish dogs and characterization of C. jejuni isolates

Background

The aims of this study were to investigate the prevalence of Campylobacter species in Swedish dogs, to identify the species of the Campylobacter isolates and to genotype the C. jejuni isolates. Young and healthy dogs were targeted and the sampling was performed at 11 veterinary clinics throughout Sweden from October 2011 to October 2012. Faecal swab samples were collected and sent to the laboratory at the National Veterinary Institute (SVA) for isolation of Campylobacter, speciation and genotyping.

Results

Campylobacter spp. were isolated from 67 of the 180 sampled dogs which yields an overall prevalence of 37%. The most prevalent species of Campylobacter among the participating dogs was C. upsaliensis with 52 of the 67 identified isolates. A lower prevalence was observed for C. jejuni with seven identified isolates and one isolate was identified as C. helveticus. Multi-locus sequence typing (MLST) was carried out on the seven C. jejuni isolates and all sequence types that were found are also commonly found in humans. The dogs were divided into three age groups; 1) under 12 months, 2) 12 to 23 months and 3) 24 months and older. The highest prevalence was found in the two younger age groups. Dogs shedding C. jejuni were between 3–12 months of age while dogs shedding C. upsaliensis were found in all ages.

Conclusions

The present investigation finds that Campylobacter spp. known to cause campylobacteriosis in humans are present in Swedish dogs. The results suggest an age predisposition where dogs under 2 years of age are more likely to shed Campylobacter spp. than older dogs. The most commonly isolated species was C. upsaliensis followed by C. jejuni, which was only detected in dogs up to 12 months of age. All C. jejuni isolates identified in the present study were of the same MLST types that have previously been described both in humans and in animals. The awareness of the Campylobacter risk of healthy young dogs may be an important way to reduce the transmission from dogs to infants, young children and immunocompromised adults.     

Prevalence and antimicrobial susceptibility of Salmonella spp. in small Indian mongooses (Herpestes auropunctatus) in Grenada,West Indies

Intestinal samples from 156 small Indian mongooses (Herpestes auropunctatus) collected island-wide in Grenada from April 2011 to March 2013 were examined for the presence of Salmonella enterica spp. Nineteen (12%) mongooses were culture-positive for S. enterica spp. of which five serotypes were identified. Salmonella javiana and S. Montevideo were the most commonly isolated serotypes. The other serotypes isolated were S. Rubislaw, S. Panama and S. Arechavaleta. All isolates were susceptible to amoxicillin–clavulanic acid, ampicillin, cefotaxime, ceftazidime, ciprofloxacin, enrofloxacin, gentamicin, nalidixic acid, imipenem and trimethoprim–sulfamethoxazole. One isolate (S. Montevideo) showed resistance to tetracycline and intermediate resistance to streptomycin. The five isolated Salmonella serotypes are potential human pathogens suggesting that the mongoose may play a role in the epidemiology of human salmonellosis in Grenada.