Occurrence of gram-negative bacteria in hens' eggs depending on their source and storage conditions

The aim of this study was to analyse the qualitative composition of Gram-negative microbes, mainly of the family Enterobacteriaceae, including pathogenic bacteria such as Salmonella, in the albumens and yolks and on the shells of hens' eggs, depending on their source and on the temperature and duration of their storage. A total of 375 table eggs were studied, from a large-scale poultry farm, a small-scale poultry farm and a supermarket. Each group was divided into 5 subgroups according to the temperature and duration of their storage during the study. Two serotypes of bacteria of the genus Salmonella were identified: S. Enteritidis and S. Arizonae. Strains of Salmonella spp. were also isolated. Apart from Salmonella and Escherichia coli, among the most frequently isolated bacteria of the family Enterobacteriaceae were Enterobacter spp., Klebsiella spp. and Citrobacter freundii. Qualitative analysis of the bacterial microflora of the eggs also showed the presence of other Gram negative bacteria, including Acinetobacter spp., Pseudomonas spp., Tatumella ptyseos, Providencia stuartii, Serratia liquefaciens, Flavimonas oryzihabitans, Vibrio metschnikovii, Leclercia adecarboxylata, Kluyvera spp., Rahnella aquatilis, Proteus mirabilis, and Achromobacter spp. The study demonstrated that the conditions applied, i.e., the temperature and duration of storage, did not significantly influence the prevalence of particular species of Gram-negative bacteria in the eggs. However, based on the analysis of contamination of eggs with Salmonella depending on their source, it can be concluded that the system in which the hens are housed affects the risk of contamination of eggs with these pathogens.     

Antimicrobial therapy for multidrug resistant pathogens

Multidrug resistant bacteria are tremendous causes of morbidity and mortality in human medicine, and emerging pathogens in equine medicine. A variety of organisms, such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin resistant Enterococcus spp. (VRE) and multidrug resistant Acinetobacter spp., Pseudomonas spp. and Enterobacteriaceae are of concern in equine medicine. Veterinary practitioners need to be aware of key diagnostic, clinical, therapeutic, epidemiological and infection control aspects to limit the impact of these organisms on the equine, and perhaps human, population.     

Diversity of bacterial pathogens and their antimicrobial resistance profile among commensal rodents in Qatar

Rodents are sources of many zoonotic pathogens that are of public health concern. This study investigated bacterial pathogens and assessed their antimicrobial resistance (AMR) patterns in commensal rodents in Qatar. A total of 148 rodents were captured between August 2019 and February 2020, and blood, ectoparasites, and visceral samples were collected. Gram-negative bacteria were isolated from the intestines, and blood plasma samples were used to detect antibodies against Brucella spp., Chlamydophila abortus, and Coxiella burnetii. PCR assays were performed to detect C. burnetii, Leptospira spp., Rickettsia spp., and Yersinia pestis in rodent tissues and ectoparasite samples. Antimicrobial resistance by the isolated intestinal bacteria was performed using an automated VITEK analyzer. A total of 13 bacterial species were isolated from the intestine samples, namely Acinetobacter baumannii, Aeromonas salmonicida, Citrobacter freundii, Citrobacter koseri, Enterobacter aerogenes, Enterobacter cloacae, Escherichia coli, Hafnia alvei, Klebsiella pneumoniae, Providencia stuartii, Proteus mirabilis, Pseudomonas aeruginosa, and Salmonella enterica. The majority of them were E. coli (54.63%), followed by P. mirabilis (17.59%) and K. pneumoniae (8.33%). Most of the pathogens were isolated from rodents obtained from livestock farms (50.46%), followed by agricultural farms (26.61%) and other sources (22.94%). No antibodies (0/148) were detected against Brucella spp., C. abortus, or C. burnetii. In addition, 31.58% (6/19) of the flea pools and one (1/1) mite pool was positive for Rickettsia spp., and no sample was positive for C. burnetii, Leptospira spp., and Y. pestis by PCR. A total of 43 (38%) bacterial isolates were identified as multidrug resistant (MDR), whereas A. salmonicida (n?=?1) did not show resistance to any tested antimicrobials. Over 50% of bacterial MDR isolates were resistant to ampicillin, cefalotin, doxycycline, nitrofurantoin, and tetracycline. The presence of MDR pathogens was not correlated with rodent species or the location of rodent trapping. Seven (11.86%) E. coli and 2 (22.2%) K. pneumoniae were extended-spectrum beta-lactamases (ESBL) producers. These findings suggest that rodents can be a source of opportunistic bacteria for human and animal transmission in Qatar. Further studies are needed for the molecular characterization of the identified bacteria in this study.

     

Bacterial flora of the conjunctiva and nasal cavity in normal and diseased captive bustards.

A survey was carried out to describe the normal aerobic bacterial flora of the conjunctiva and nasal cavity of captive houbara bustards (Chlamydotis undulata), kori bustards (Ardeotis kori), and white-bellied bustards (Eupodotis senegalensis) maintained at the National Avian Research Center, Abu Dhabi, United Arab Emirates. A total of 58 samples were examined from the nasal cavity and 55 samples from the conjunctiva of healthy bustards. There was no bacterial growth in 45% of conjunctival samples. Bacteria isolated from the conjunctiva of healthy birds included Micrococcus spp., Staphylococcus auricularis, Staphylococcus xylosus, Staphylococcus capitis, Staphylococcus warneri, Bacillus spp., and Enterobacter amigenus. Bacteria isolated from the nasal cavity of healthy birds included Bacillus spp., Micrococcus spp., S. auricularis, S. xylosus, Staphylococcus simulans, Staphylococcus saprophyticus, Staphylococcus hyicus, Staphylococcus cohnii, Staphylococcus sciuri, Aerococcus spp., and Providencia rettgeri. These findings were compared with bacterial isolates from bustards with clinical signs of ocular or upper respiratory tract diseases. Mycoplasma spp., Pseudomonas aeruginosa, Pseudomonas stutzeri, Proteus mirabilis, Escherichia coli, Klebsiella spp., Aeromonas hydrophila, and Staphylococcus aureus were the pathogenic bacteria isolated from the conjunctiva of 34.3% bustards with ocular discharges. Mycoplasma spp., P. aeruginosa, Pseudomonas spp., P. mirabilis, E. coli, Klebsiella pneumoniae, and S. aureus were the pathogenic bacteria isolated from the nasal cavity of 74% bustards with upper respiratory tract diseases.     

A review of multidrug resistant surgical site infections.

Surgical site infections caused by bacteria that are resistant to multiple classes of antimicrobials are an important and increasing problem in veterinary medicine. Organisms such as methicillin-resistant staphylococci, extended spectrum beta-lactamase Enterobacteriaceae and multi-drug resistant Enterococcus, Acinetobacter and Pseudomonas spp. are among the current concerns; however, the emergence and dissemination of other multi-drug resistant organisms will likely follow. Despite the negative connotations that are associated with multi-drug resistant infections, most infections are potentially treatable if basic principles of infection treatment and infection control are followed.     

Providencia alcalifaciens as the presumptive cause of diarrhoea in dog

A case of diarrhoea in a four-month-old golden retriever is described. On the basis of anamnesis and bacteriological examination, the diagnosis of bacterial enteritis due to Providencia alcalifaciens was reached. Although there are contradictory opinions about the role of this organism as the enteric pathogen, it seems that Providencia alcalifaciens should also be taken into consideration in the routine bacteriological diagnostics of diarrhoea in dogs.     

Tetracycline Resistance of Enterobacteriaceae Isolated From Feces of Synanthropic Birds

Tetracycline is a broad-spectrum antibiotic which is commonly used in humans and animals for treatment of bacterial infections. Therefore, tetracycline-resistant Enterobacteriaceae species found in the nature, humans, and animals are usually considered a serious health concern. The feces of birds that live with humans may be a source for of these antibiotic resistant bacteria. For this reason, presence of tetracycline-resistant Enterobacteriaceae in bird droppings collected from 18 different breeders and pet shops fed in Istanbul was investigated by cultural and molecular methods in terms of the presence of that a/b gene. In addition, susceptibilities of isolates to various antibiotics were also determined. The current study reported that Enterobacter cloacae, Citrobacter freundi, Escherichia coli, Edwardsiella spp., Enterobacter spp., Escherichia vulneris, Klebsiella pneumonia, Pantoea agglomerans, Proteus mirabilis, Pantoe spp., Pseudomonas spp., Serratia marcescens, Salmonella spp., Shigella spp. were isolated from the samples. Ninety-seven of the isolates (97/150) were resistant to tetracycline (65.2%). In addition, the isolates were resistant to other antibiotic medications and 114 of them (58%) evaluated as multi drug resistant. The tet (A) and tet (B) genes were found in bacteria isolated from synantrophic birds’ feces as 46.6% and 8%, respectively. Although working conditions are limited, the results obtained provide baseline information regarding antibiotic resistance to Enterocatericeae isolates obtained from captive birds’ feces. Thus, the results of the present study emphasize the necessity of genotypic resistance research in future studies to help maintain antibiotic treatment efficacy for Enterocatericeae infections.     

Multigeneric resistance to benzimidazole anthelmintics in four sheep flocks

Clinical parasitism associated with multigeneric resistance to benzimidazole anthelmintics was investigated in four sheep flocks during February and March 1989. The genera considered resistant were Haemonchus and Nematodirus spp. on all four farms and Trichostrongylus and Ostertagia spp. on three of the four farms. It is suggested that when investigating cases of suspected drench resistance, post-drenching worm counts are useful to help identify the resistant worm species present.     

Comparison of antimicrobial resistance in generic Escherichia coli and Salmonella spp. cultured from identical fecal samples in finishing swine

The objectives of this study were to investigate the associations between antimicrobial resistance patterns in generic Escherichia coli and Salmonella spp. isolates recovered from identical pen pooled fecal samples, and to evaluate potential clustering of multiple isolates of these organisms within identical fecal samples. Up to 5 generic E. coli (n = 922 isolates) and Salmonella spp. (n = 922 isolates) isolates were obtained from each of 188 pen pooled fecal samples that had been collected from 45 finishing swine farms in Alberta in 2000, and tested for susceptibility to 15 antimicrobials. No isolates of either organism were resistant to 3rd generation cephalosporins or fluoroquinolones, which in Canada are considered antimicrobials of very high importance to human health. Approximately twice as many generic E. coli isolates as Salmonella spp. isolates were resistant to at least 1 antimicrobial. In addition, E. coli isolates showed more multidrug-resistance patterns. No significant association was observed between the resistance phenotypes of Salmonella spp. and E. coli at the fecal sample level. More clustering at the sample level was observed for proportions of antimicrobial resistance (AMR) in Salmonella spp. isolates than E. coli indicating that in future studies it might be sufficient to test fewer than 5 Salmonella spp. isolates per sample.     

Antimicrobial resistance of bacteria isolated from dairy cow milk samples submitted for bacterial culture: 8,905 samples (1994-2001)

OBJECTIVE: To determine whether antimicrobial resistance patterns of major mastitis pathogens isolated from milk samples from dairy cows have changed over time. DESIGN: Retrospective study. SAMPLE POPULATION: 8905 bacterial isolates obtained from milk samples submitted to the Wisconsin Veterinary Diagnostic Laboratory between January 1994 and June 2001. PROCEDURE: Antimicrobial susceptibility was determined by means of the Kirby-Bauer disk diffusion method. Logistic regression was used to determine whether percentages of isolates resistant to various antimicrobials changed over time. RESULTS: For the gram-positive mastitis pathogens, percentages of isolates resistant to various flactam antimicrobials did not increase over the course of the study. Percentage of Staphylococcus aureus isolates resistant to penicillin decreased from 49 to 30%; percentage of Streptococcus isolates resistant to penicillin decreased from 6 to 1%. Percentage of isolates resistant to erythromycin increased for S aureus, Escherichia coli, Enterobacter spp, Enterococcus spp, and Pasteurella spp. Percentage of isolates resistant to lincomycin increased for S aureus and Staphylococcus spp. Percentage of coagulase-negative Staphylococcus isolates resistant to pirlimycin increased from 6 to 19%. For several pathogens, percentages of isolates resistant to sulfisoxazole and to trimethoprim-sulfamethoxazole decreased. No pathogens had a significant increase in the percentage of isolates resistant to novobiocin-penicillin. CONCLUSIONS AND CLINICAL RELEVANCE: Results did not indicate a trend toward increased antimicrobial resistance among mastitis pathogens isolated from milk samples from dairy cows between 1994 and 2001. Reduced resistance to flactam antimicrobials was identified for several gram-positive mastitis pathogens.     

乳房炎源生鲜乳中病原微生物的污染现状及防控措施

主要介绍了乳房炎患病牛乳中病原微生物污染情况、耐药情况及防控措施。总结出乳房炎患病牛乳中的病原微生物种类较多, 主要有大肠杆菌、金黄色葡萄球菌、链球菌和克雷伯菌, 不同地区乳房炎乳样中的病原微生物不同, 产生的耐药性和耐药基因存在差异。旨在为减少因滥用和乱用抗生素导致药物残留和耐药性产生、降低乳房炎患病牛乳中病原微生物的污染以及科学、合理用药提供参考。     

Multigeneric resistance to benzimidazole anthelmintics in four sheep flocks

Clinical parasitism associated with multigeneric resistance to benzimidazole anthelmintics was investigated in four sheep flocks during February and March 1989. The genera considered resistant were Haemonchus and Nematodirus spp. on all four farms and Trichostrongylus and Ostertagia spp. on three of the four farms. It is suggested that when investigating cases of suspected drench resistance, postdrenching worm counts are useful to help identify the resistant worm species present.     

Antibiotic resistance in Escherichia coli and Enterococcus spp. isolates from commercial broiler chickens receiving growth-promoting doses of bacitracin or virginiamycin

Antibacterial agents such as zinc bacitracin (ZB) and virginiamycin (VG) are used as growth promoting agents (GP) in broiler chicken production. The objective of this study was to evaluate the effect of the use of ZB and VG on the emergence of antibacterial resistance in a commercial broiler chicken farm. Three trials were conducted using 3 different diets: one without antibacterial agents, one containing VG, and one with ZB. Escherichia coli and Enterococcus spp. strains were isolated and tested for their susceptibility to various antibacterial agents. The occurrence of the resistance genes vatD, ermB, and bcrR in Enterococcus spp. isolates was determined by polymerase chain reaction (PCR). Comparative quantification of vatD and bcrR genes in total deoxyribonucleic acid (DNA) extracts from litter was done by SYBR Green Real-Time PCR (QPCR). Escherichia coli and Enterococcus spp. isolates from diet groups had different levels of resistance to various antibacterial agents over time. These GPs did not select for specific antibacterial agent resistance (AAR) in Enterococcus spp. The use of GPs seemed to lower the percentage of E. coli isolates resistant to some antibacterial agents. The presence of the bcrR gene could not explain all resistant phenotypes to ZB. Genes other than vatD and ermB might be involved in the resistance to VG in Enterococcus spp. Use of GPs was not associated with presence of the bcrR gene in DNA extracts from litter, but use of VG was associated with vatD presence.     

Non-confirmation of anthelmintic resistance in Ostertagia spp

An investigation was undertaken to confirm the existence of a mebendazole-resistant strain of Ostertagia spp. on a ram-breeding property in Taihape. The results indicated that while a strain of Haemonchus contortus from this farm was highly resistant to mebendazole, an isolate of Ostertagia spp. was fully susceptible. Possible reasons for the discrepancy between previous and present findings are briefly discussed.     

Intestinal microflora in 45 crows in Ueno Zoo and the in vitro susceptibilities of 29 Escherichia coli isolates to 14 antimicrobial agents

Microorganisms from 45 jungle crows (Corvus macrorhynchos) captured from July to December 2002 at Ueno Zoo, Tokyo were identified as Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter aerogenes, Enterobacter cloacae, Enterobacter agglomerans, Pseudomonas maltophila, Staphylococcus spp., Micrococcus spp., and Streptococcus spp. E. coli showed the highest rate of isolation (21.6%). In an in vitro susceptibility test for 29 isolates of E. coli to 14 antimicrobial agents, all the isolates were resistant to penicillin G, vancomycin, erythromycin, lincomycin, bicozamycin, sulfadimethoxine, and olaquindox. Several isolates of them were also resistant to tetracycline, oxytetracycline, streptomycin, chloramphenicol, and ampicillin. Twenty-nine isolates were divided into 19 serogroups and the most frequently identified serogroups were O8, O114 and O144, which showed the same multidrug-resistant patterns.     

Antimicrobial Susceptibility of Microorganisms Isolated from Equine Orthopedic Patients

Positive cultures were obtained from 60 equine orthopedic cases during a 12 year period (1974-1985). These cases consisted of 34 long or cuboidal bone fractures, 13 arthrotomy/arthroscopy procedures for removal or internal fixation of a fracture, 7 proximal splint bone fractures, and 6 facial or mandibular fractures. Excluding the 13 arthrotomies, only 10 (21%) of the 47 were open fractures. Multiple organisms were isolated from 36 cases (20 long or cuboidal bone fractures, 7 splint bone fractures, 5 mandibular fractures, and 4 intra-articular fractures). Of the 142 isolates, 35 (24%) were members of the family Enterobacteriaceae, 33 (23%) Streptococcus spp., and 25 (18%) Staphylococcus spp. with the majority being coagulase positive (65%). Other organisms isolated were Pseudomonas spp. (16, 11%), obligate anaerobes (11, 7%), and Actinobacillus spp. (7, 5%). the remaining 10% consisted of Pasteurella spp., Bacillus spp., Corynebacterium spp., Micrococcus spp., and Actinomyces spp. When comparing results between two time periods (1974-1979 and 1980-1985) there was an increase in the percentage of coagulase positive staphylococci isolates resistant to all antimicrobics tested except oxacillin and amikacin, and Escherichia coli isolates were resistant to all but amikacin. For Pseudomonas spp., resistance to gentamicin increased in the second time period (1980-1986). During the initial time period (1974-1979) culture tests for obligate anerobes were not conducted until 1975. No anerobes were cultured during those initial 5 years; however, one third of those isolated after 1980 were resistant to penicillin and ampicillin.(ABSTRACT TRUNCATED AT 250 WORDS)     

Canine bacterial urinary tract infections: new developments in old pathogens

Uncomplicated bacterial urinary tract infections (UTIs) occur commonly in dogs. Persistent or recurrent infections are reported less frequently. They typically occur in dogs with an underlying disease and are sometimes asymptomatic, especially in dogs with predisposing chronic disease. Escherichia coli is the organism most frequently cultured in both simple and complicated UTIs. Organisms such as Enterococcus spp. and Pseudomonas spp. are less common in uncomplicated UTI, but become increasingly prominent in dogs with recurrent UTI. The ability of bacteria to acquire resistance to antimicrobials and/or to evade host immune defence mechanisms is vital for persistence in the urinary tract. Antimicrobial therapy limitations and bacterial strains with such abilities require novel control strategies. Sharing of resistant bacteria between humans and dogs has been recently documented and is of particular concern for E. coli O25b:H4-ST131 strains that are both virulent and multi-drug resistant. The epidemiology of complicated UTIs, pathogenic traits of uropathogens and new therapeutic concepts are outlined in this review.     

beta-Lactam resistance and beta-lactamases in bacteria of animal origin

beta-Lactams are among the most clinically important antimicrobials in both human and veterinary medicine. Bacterial resistance to beta-lactams has been increasingly observed in bacteria, including those of animal origin. The mechanisms of beta-lactam resistance include inaccessibility of the drugs to their target, target alterations and/or inactivation of the drugs by beta-lactamases. The latter contributes predominantly to beta-lactam resistance in Gram-negative bacteria. A variety of beta-lactamases have been identified in bacteria derived from food-producing and companion animals and may further serve as a reservoir for beta-lactamase-producing bacteria in humans. While this review mainly describes beta-lactamases from animal-derived Escherichia coli and Salmonella spp., beta-lactamases from animal-derived Campylobacter spp., Enterococcus spp., Staphylococcus spp. and other pathogens are also discussed. Of particular concern are the increasingly-isolated plasmid-encoded AmpC-type CMY and extended-spectrum CTX-M beta-lactamases, which mediate acquired resistance to extended-spectrum beta-lactams. The genes encoding these enzymes often coexist with other antimicrobial resistance determinants and can also be associated with transposons/integrons, increasing the potential enrichment of multidrug resistant bacteria by multiple antimicrobial agents as well as dissemination of the resistance determinants among bacterial species. Characterization of beta-lactam-resistant animal-derived bacteria warrants further investigation of the type and distribution of beta-lactamases in bacteria of animal origin and their potential impact on human medicine.     

Corynebacterium spp. in Dogs and Cats with Otitis Externa and/or Media: A Retrospective Study

The role of Corynebacterium spp. in the pathogenesis of canine and feline otitis externa/media and their appropriate antimicrobial therapy are unclear. The objectives of this study were to (1) better establish the pathogenicity of Corynebacterium spp. in otitis utilizing reported criteria and by assessing clinical response to antibiotic therapy and (2) to determine the antimicrobial susceptibility patterns of Corynebacterium spp. associated with otitis. The study was retrospective, targeting cultures positive for Corynebacterium spp. Corynebacterium spp. were part of mixed microbial populations in 79/81 cultures. Corynebacterium spp. pathogenicity was highly questionable because of their almost invariable presence with other microbes and the observation that Corynebacterium spp. usually disappear from the ear with resolution of other infections, even when the Corynebacterium spp. are resistant to the prescribed antibiotic(s). However, 2/81 cultures came from two canine ears wherein Corynebacterium spp. may have been pathogenic. Antimicrobial sensitivities for Corynebacterium spp. were available for 54 isolates. Most isolates were susceptible to chloramphenicol (53/54), amikacin (50/54), tetracycline (50/54), gentamicin (46/54), and enrofloxacin (32/54). Among those antibiotics available in otic products, gentamicin and enrofloxacin would be rational choices for the empirical, topical therapy of Corynebacterium spp.     

白鳍鲨雷极氏普罗菲登斯菌的分离鉴定与药敏试验

从北京海洋馆死亡的白鳍鲨腹腔脓液和心血中分离到一株病原菌,经生理生化、培养特性、16S rRNA序列鉴定为雷极氏普罗菲登斯菌。以16S rRNA序列为基础构建了包括普罗菲登斯菌属模式株在内的系统发育树,分离菌株与雷极氏普罗菲登斯菌模式株DSM4542的同源性最近。药敏试验结果表明,该菌对氨曲南、头孢曲松、磷霉素、哌拉西林、头孢呋辛钠、诺氟沙星、头孢哌酮敏感。毒力试验结果显示该菌可致小鼠死亡。