Multi-drug-resistant Acinetobacter calcoaceticus-Acinetobacter baumannii complex infection outbreak in dogs and cats in a veterinary hospital

Phenotypic Investigation and Detection of Biofilm-Associated Genes in Acinetobacter baumannii Isolates, Obtained from Companion Animals

Bacteria of the genus Acinetobacter, especially Acinetobacter baumannii (Ab), have emerged as pathogens of companion animals during the last two decades and are commonly associated with hospitalization and multidrug resistance. A critical factor for the distribution of relevant strains in healthcare facilities, including veterinary facilities, is their adherence to both biotic and abiotic surfaces and the production of biofilms. A group of 41 A. baumannii isolates obtained from canine and feline clinical samples in Greece was subjected to phenotypic investigation of their ability to produce biofilms using the tissue culture plate (TCP) method. All of them (100%) produced biofilms, while 23 isolates (56.1%) were classified as strong producers, 11 (26.8%) as moderate producers, and 7 (17.1%) as weak producers. A correlation between the MDR and XDR phenotypes and weak or moderate biofilm production was identified. Moreover, the presence of four biofilm-associated genes bap, blaPER, ompA, and csuE was examined by PCR, and they were detected in 100%, 65.9%, 97.6%, and 95.1% of the strains respectively. All isolates carried at least two of the investigated genes, whereas most of the strong biofilm producers carried all four genes. In conclusion, the spread and persistence of biofilm-producing Ab strains in veterinary facilities is a matter of concern, since they are regularly obtained from infected animals, indicating their potential as challenging pathogens for veterinarians due to multidrug resistance and tolerance in conventional eradication measures. Furthermore, considering that companion animals can act as reservoirs of relevant strains, public health concerns emerge.

Predominance of Acinetobacter pseudolwoffii among Acinetobacter species in domestic animals in the Czech Republic

The aim of this study was to map the spectrum of microorganisms belonging to the genus Acinetobacter in domestic animals with a specific focus on the prevalence of Acinetobacter pseudolwoffii. Additionally, the susceptibility of isolates to antimicrobial agents was determined. In the period from January 1, 2014, to August 31, 2015, a total of 9 544 samples originating from gross lesions and pathological processes of animals exhibiting clinical symptoms of the disease were examined across 41 districts in the Czech Republic. The examinations were carried out using culture methods involving meat-peptone blood agar and Endo agar under aerobic conditions at a temperature of 37 ± 1 °C for 18-24 hours. Isolates were confirmed using molecular phenotypic method MALDI-TOF MS with the MBT Compass Library Revision L 2020 covering 3 239 species/entries (9 607 MSP) from Bruker Daltonics company. Out of the 108 isolates (prevalence 1.13%), 14 species of Acinetobacter spp. were identified, with 5 isolates remaining unclassified as species. A. pseudolwoffii was the predominant species isolated in 25 cases (prevalence 0.26%). Antimicrobial susceptibility was determined for 12 antimicrobials by the disc diffusion method, with A. pseudolwoffii isolates exhibiting the lowest susceptibility to ceftazidime (32%) and co-trimoxazole (60%).

Antimicrobial Susceptibility Profiles of Acinetobacter baumannii Strains, Isolated from Clinical Cases of Companion Animals in Greece

Acinetobacter baumannii-calcoaceticus (Abc) Complex bacteria are troublesome nosocomial pathogens in human medicine, especially during the last 30 years. Recent research in veterinary medicine also supports its emergence as an animal pathogen. However, relevant data are limited. In this study, we obtained 41 A. baumannii isolates from clinical samples of canine and feline origin collected in veterinary clinics in Greece between 2020 and 2023. Biochemical identification, antimicrobial susceptibility testing, molecular identification and statistical analysis were performed. Most of the samples were of soft tissue and urine origin, while polymicrobial infections were recorded in 29 cases. Minocycline was the most effective in vitro antibiotic, whereas high resistance rates were detected for almost all the agents tested. Notably, 20 isolates were carbapenem resistant and 19 extensively drug resistant (XDR). This is the first report of canine and feline infections caused by Abc in Greece. The results create concerns regarding the capability of the respective bacteria to cause difficult-to-treat infections in pets and persist in veterinary facilities through hospitalized animals, contaminated equipment, and surfaces. Moreover, the prevalence of highly resistant strains in companion animals constitutes a public health issue since they could act as a reservoir, contributing to the spread of epidemic clones in a community.

Removal of bacterial pathogens and antibiotic resistance bacteria by anaerobic sludge digestion with thermal hydrolysis pre-treatment and alkaline stabilization post-treatment

Primary sludge (PS) is associated with public health and environmental risks, so regulations focus on reducing the pathogenic and heavy metal contents of the treated material (biosolids), intended for soil amendments and land reclamation. The regulations set limits for Escherichia coli (or fecal coliforms), Salmonella spp., helminth eggs and enterovirus. However, the potential risk due to antibiotic resistant bacteria (ARB) and other human potential pathogenic bacteria (HPB) are not considered. In this work, three sludge treatment processes, having in common an anaerobic digestion step, were applied to assess the removal of regulated bacteria (fecal coliforms, Salmonella spp), ARB and HPB. The treatment arrangements, fed with PS from a full-scale wastewater treatment plant were: 1) Mesophilic anaerobic digestion followed by alkaline stabilization post-treatment (MAD-CaO); 2) Thermophilic anaerobic digestion (TAD) and, 3) Pre-treatment (mild thermo-hydrolysis) followed by TAD (PT-TAD). The results address the identification, quantification (colony forming units) and taxonomic characterization of ARB resistant to β-lactams and vancomycin, as well as the taxonomic characterization of HPB by sequencing with PacBio. In addition, quantification based on culture media of fecal coliforms and Salmonella spp. is presented. The capabilities and limitations of microbiological and metataxonomomic analyses based on PacBio sequencing are discussed, emphasizing that they complement each other. Genus Aeromonas, Acinetobacter, Citrobacter, Enterobacter, Escherichia, Klebsiella, Ochrobactrum, Pseudomonas and Raoultella, among others, were found in the PS, which are of clinical or environmental importance, being either HPB, HPB-ARB, or non-pathogenic ARB with the potentiality of horizontal gene transfer. Based on the analysis of fecal coliforms and Salmonella spp., the three processes produced class A (highest) biosolids, suitable for unrestricted agriculture applications. Mild thermo-hydrolisis was effective in decreasing ARB cultivability, but it reappeared after the following TAD. O. intermedium (HPB-ARB) was enriched in MAD and TAD while Laribacter hongkongensis (HPB) did persist after the applied treatments.

Emergence and multi-lineages of carbapenemase-producing Acinetobacter baumannii-calcoaceticus complex from canine and feline origins

The carbapenemase-producing Acinetobacter baumannii is an important opportunistic bacterium and frequently causes hospital-acquired infections in humans. It also has increasingly been reported in veterinary medicine. This study illustrates multiple clones of carbapenemase-producing A. baumannii disseminating and causing diseases in dogs and cats in Thailand. Between 2016 and 2020, 44 A. baumannii and two A. pittii isolates exhibiting imipenem resistance (MIC≥16 μg/mL) from diagnostic samples were characterized by Pasteur multilocus sequence typing (MLST), sequence grouping (SG), repetitive extragenic palindromic element (rep)-PCR fingerprint analysis and antimicrobial resistance (AMR) profiling. All isolates contained bla_OXA-23 in the Tn2006 family, and A. baumannii showed the sequence type (ST) 16 (14/44), ST149 (12/44), ST25 (6/44), ST2 (4/44), ST1581 (3/44), ST23 (2/44), ST1575 (1/44) and ST1576 (1/44). DNA fingerprint analysis and SG illustrated clonal relationships in the STs and its single locus variants, and AMR gene profiles, including tetracycline and aminoglycoside resistance genes, showed minor variations in the clones. The findings suggest that bla_OXA-23 has been spread in multiple clones of A. baumannii and A. pittii from canine and feline hosts. With the collection of multiple AMR genes and intrinsic resistance, antimicrobial options are limited for treatment, and pets can be a potential reservoir of extensively drug-resistant, carbapenemase-producing A. baumannii in the community. Epidemiological tracking by passive and active surveillance in animals, veterinary personnel and hospital environment and preventive measurements should be promoted to decrease the risk of infection and transmission to humans.

Metagenomics Analysis Reveals the Microbial Communities, Antimicrobial Resistance Gene Diversity and Potential Pathogen Transmission Risk of Two Different Landfills in China

In this study, we used a metagenomic approach to analyze microbial communities, antibiotic resistance gene diversity, and human pathogenic bacterium composition in two typical landfills in China. Results showed that the phyla Proteobacteria, Bacteroidetes, and Actinobacteria were predominant in the two landfills, and archaea and fungi were also detected. The genera Methanoculleus, Lysobacter, and Pseudomonas were predominantly present in all samples. sul2, sul1, tetX, and adeF were the four most abundant antibiotic resistance genes. Sixty-nine bacterial pathogens were identified from the two landfills, with Klebsiella pneumoniae, Bordetella pertussis, Pseudomonas aeruginosa, and Bacillus cereus as the major pathogenic microorganisms, indicating the existence of potential environmental risk in landfills. In addition, KEGG pathway analysis indicated the presence of antibiotic resistance genes typically associated with human antibiotic resistance bacterial strains. These results provide insights into the risk of pathogens in landfills, which is important for controlling the potential secondary transmission of pathogens and reducing workers’ health risk during landfill excavation.

The Role of Antibiotic Resistant A. baumannii in the Pathogenesis of Urinary Tract Infection and the Potential of Its Treatment with the Use of Bacteriophage Therapy

Acinetobacter baumannii are bacteria that belong to the critical priority group due to their carbapenems and third generation cephalosporins resistance, which are last-chance antibiotics. The growing multi-drug resistance and the ability of these bacteria to form biofilms makes it difficult to treat infections caused by this species, which often affects people with immunodeficiency or intensive care unit patients. In addition, most of the infections are associated with catheterization of patients. These bacteria are causative agents, inter alia, of urinary tract infections (UTI) which can cause serious medical and social problems, because of treatment difficulties as well as the possibility of recurrence and thus severely decrease patients' quality of life. Therefore, a promising alternative to standard antibiotic therapy can be bacteriophage therapy, which will generate lower costs and will be safer for the treated patients and has real potential to be much more effective. The aim of the review is to outline the important role of drug-resistant A. baumannii in the pathogenesis of UTI and highlight the potential for fighting these infections with bacteriophage therapy. Further studies on the use of bacteriophages in the treatment of UTIs in animal models may lead to the use of bacteriophage therapy in human urinary tract infections caused by A. baumannii in the future.

A multicenter observational study investigating care errors, staffing levels, and workload in small animal intensive care units

OBJECTIVE

To investigate associations among care errors, staffing, and workload in small animal ICUs.

DESIGN

Multicenter observational cohort study conducted between January 2017 and September 2018.

SETTING

Three small animal teaching hospital ICUs.

ANIMALS

None.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Data on patient numbers, illness severity (assesed via the acute patient physiologic and laboratory evaluation [APPLE] score), care burden, staffing levels, technician experience/education level, and care errors were collected at each study site. Care errors were categorized as major (unanticipated arrest or death; patient endangerment through IV line, arterial catheter, chest tube or other invasive device mismanagement, or errors in drug calculation/administration) or minor. Median patient:technician ratio was 4.3 (range: 1-18). Median patient illness severity was 15.1 (4.7-27.1) APPLE score units. A total of 221 major and 3,317 minor errors were observed over the study period. The odds of a major error increased by an average of 11% (odds ratio [OR] = 1.11; 95% confidence interval [CI], 1.02-1.20; P = 0.012) for each 1 patient increase in the patient:technician ratio after averaging by ICU location. The major error incident rate ratio was 2.53 (95% CI, 1.84-3.54; P < 0.001) for patient:technician ratios of >4.0 compared with ≤4.0. The odds of a major error increased by 0.5% per total unit APPLE score increase (OR = 1.005; 95% CI, 1.002-1.007; P < 0.001). The major error incident rate ratio was 1.71 (95% CI, 1.30-2.25; P < 0.001) for APPLE_fast :technician ratios of >73 compared with ≤73. The odds of a major error decreased by 2% (OR = 0.98; 95% CI, 0.97-0.99; P = 0.01) for each year increase in total technician years of ICU work experience.

CONCLUSIONS

Substantial reductions in major care errors may be achieved by maintaining ICU patient:technician ratios at ≤4. Technician experience and total unit burden of patient illness severity are also associated with error incidence, and should be taken into consideration when scheduling staff.

Polyarthritis Caused by Acinetobacter kookii in a Rothschild's Giraffe Calf (Giraffa camelopardalis rothschildi)

We report the first isolation of Acinetobacter kookii from a Rothschild's giraffe calf (Giraffa camelopardalis rothschildi) that had severe polyarthritis. The isolate was resistant to more than one representative of each of four classes of antibiotics (penicillins, macrolides, lincosamides and tetracyclines). As A. kookii has not been previously associated with disease in humans or animals, it may be an emerging opportunistic pathogen posing a threat to immunocompromised patients. Furthermore, as transmission of Acinetobacter spp. with similar patterns of antimicrobial resistance has been previously reported in human and animal populations, special care should be taken when handling infected animals.

Detection of a novel clone of Acinetobacter baumannii isolated from a dog with otitis externa

In this study, the isolation of Acinetobacter baumannii in a dog with clinical bilateral otitis externa is described. Moreover, to investigate the zoonotic potential of the isolate, microbiological examinations on the family members were performed. An A. baumanniistrain was isolated from nasal swab in one of the dog owners. The identity of bacterial strains, either from dog and owner, was confirmed by phenotypic and molecular typing (wgMLST). Furthermore, to assess the pathogenic potential of the isolates a deep characterization of virulence and antibiotic resistance genes was done by Whole Genome Sequencing (WGS). Finally, the susceptibility towards a wide panel of antimicrobials was investigated. In our knowledge, this is the first recorded case of A. baumanniiisolation from canine auricular swabs in Italy. And interestingly, this study underlines the possible spread of this microorganism from human to animal.

Virulent Epidemic Pneumonia in Sheep Caused by the Human Pathogen Acinetobacter baumannii

The human pathogen Acinetobacter baumannii has emerged as a frequent cause of hospital-acquired infections, but infection of animals has rarely been observed. Here we analyzed an outbreak of epidemic pneumonia killing hundreds of sheep on a farm in Pakistan and identified A. baumannii as the infecting agent. A pure culture of strain AbPK1 isolated from lungs of sick animals was inoculated into healthy sheep, which subsequently developed similar disease symptoms. Bacteria re-isolated from the infected animals were shown to be identical to the inoculum, fulfilling Koch’s postulates. Comparison of the AbPK1 genome against 2283 A. baumannii genomes from the NCBI database revealed that AbPK1 carries genes for unusual surface structures, including a unique composition of iron acquisition genes, genes for O-antigen synthesis and sialic acid-specific acetylases of cell-surface carbohydrates that could enable immune evasion. Several of these unusual and otherwise rarely present genes were also identified in genomes of phylogenetically unrelated A. baumannii isolates from combat-wounded US military from Afghanistan indicating a common gene pool in this geographical region. Based on core genome MLST this virulent isolate represents a newly emerging lineage of Global Clone 2, suggesting a human source for this disease outbreak. The observed epidemic, direct transmission from sheep to sheep, which is highly unusual for A. baumannii, has important consequences for human and animal health. First, direct animal-to-animal transmission facilitates fast spread of pathogen and disease in the flock. Second, it may establish a stable ecological niche and subsequent spread in a new host. And third, it constitutes a serious risk of transmission of this hyper-virulent clone from sheep back to humans, which may result in emergence of contagious disease amongst humans.

Antimicrobial use practices of veterinary clinicians at a veterinary teaching hospital in the United States

Indiscriminate antimicrobial use (AMU) is a factor contributing to antimicrobial resistance (AMR). The objectives of this study were to (1) identify factors influencing AMU practices of veterinary clinicians at The University of Tennessee Veterinary Medical Center (UTVMC), (2) analyze the clinicians' preferential choices of antimicrobials, and (3) evaluate their perceptions, opinions, and concerns regarding AMU and AMR. A total of 121 clinicians were surveyed. Among the 62 respondents, culture and susceptibility test results and pressure from clients were the most and least important factors in their antimicrobial prescription decision-making, respectively. Compared to clinicians who obtained their veterinary degree from 1970 to 1999, those who graduated from 2000 to 2009 and 2010-2016 were 3.96 (P = 0.034) and 5.39 (P = 0.01) times less concerned about AMR, respectively. There is a critical need to increase awareness about judicious AMU practices among clinicians, increase emphasis about AMR in the present veterinary curriculum, and implement antimicrobial stewardship program (AMS) in this institution. Educational activities in combination with awareness campaigns and the stewardship programs could be used to improve AMU practices at this hospital. More client education on AMR is needed.

Species distribution, virulence factors, and antimicrobial resistance of Acinetobacter spp. isolates from dogs and cats: a preliminary study

We investigated the prevalence of virulence factors and antimicrobial resistance among 67 Acinetobacter spp. isolates, consisting of 21 Acinetobacter baumannii and 46 non-baumannii Acinetobacter from companion animals. The PCR analysis showed that the most prevalent virulence gene was afa/draBC (29.9%), followed by papC (22.4%) and cvaC (20.9%). Antimicrobial susceptibility testing revealed that resistance to gentamicin (14.9%) and ciprofloxacin (11.9%) was relatively prevalent. Five gentamicin- and/or ciprofloxacin-resistant A. baumannii strains were assigned to ST25, ST149, ST164, ST203, and ST1198. All ciprofloxacin-resistant isolates harbored point mutations in gyrA and/or parC. This is the first preliminary monitoring of animal-origin Acinetobacter spp. in Japan.

Screening of potential lead molecules against prioritised targets of multi-drug-resistant-Acinetobacter baumannii - insights from molecular docking, molecular dynamic simulations and in vitro assays

Acinetobacter baumannii, an opportunistic pathogen, has become multi-drug resistant (MDR) to major classes of antibacterial and poses grave threat to public health. The current study focused to screen novel phytotherapeutics against prioritised targets of Acinetobacter baumannii by computational investigation. Fourteen potential drug targets were screened based on their functional role in various biosynthetic pathways and the 3D structures of 9 targets were retrieved from Protein Data Bank and others were computationally predicted. By extensive literature survey, 104 molecules from 48 herbal sources were screened and subjected to virtual screening. Ten clinical isolates of A. baumannii were tested for antibiotic susceptibility towards clinafloxacin, imipenem and polymyxin-E. Computational screening suggested that Ajmalicine ((19α)-16, 17-didehydro-19-methyloxayohimban-16-carboxylic acid methyl ester from Rauwolfia serpentina), Strictamin (Akuammilan-17-oic acid methyl ester from Alstonia scholaris) and Limonin (7, 16-dioxo-7, 16-dideoxylimondiol from Citrus sps) exhibited promising binding towards multiple drug targets of A. baumannii in comparison with the binding between standard drugs and their targets. Limonin displayed promising binding potential (binding energy -9.8 kcal/mol) towards diaminopimelate epimerase (DapF) and UDP-N-acetylglucosamine 1-carboxyvinyltransferase (MurA). Ajmalicine and Strictamin demonstrated good binding potential (-9.5, -8.5 kcal/mol, respectively) towards MurA and shikimate dehydrogenase (-7.8 kcal/mol). Molecular dynamic simulations further validated the docking results. In vitro assay suggested that the tested isolates exhibited resistance to clinafloxacin, imipenem and polymyxin-E and the herbal preparations (crude extract) demonstrated a significant antibacterial potential (p ≤ .05). The study suggests that the aforementioned lead candidates and targets can be used for structure-based drug screening towards MDR A. baumannii.

Isolation and identification of Acinetobacter spp. from healthy canine skin

BACKGROUND

Acinetobacter species can exhibit widespread resistance to antimicrobial agents. They are already recognized as important nosocomial pathogens of humans, but are becoming increasingly recognized in opportunistic infections of animals.

HYPOTHESIS/OBJECTIVES

This study aimed to determine whether Acinetobacter spp. are carried on skin of healthy dogs and, if present, to identify the species.

ANIMALS

Forty dogs were sampled at veterinary practices and rescue centres. They were free from skin disease and receiving no systemic or topical treatments.

METHODS

Skin swab samples were collected from four sites on each dog and cultured. Acinetobacter spp. isolates were detected by biochemical tests and gas chromatography. The species was determined by sequencing the RNA polymerase β-subunit (rpoB) gene. Isolates were screened for OXA carbapenemase genes and class 1 integrons capable of carrying resistance genes, and subjected to antimicrobial susceptibility tests.

RESULTS

For 25% dogs sampled (10 of 40), Acinetobacter spp. were isolated at one or more skin sites. Thirteen Acinetobacter spp. isolates were recovered from 160 samples. The most frequently cultured was A. lwoffii (seven of 13), followed by A. baumannii (two of 13), A. junii (one of 13), A. calcoaceticus (one of 13), A. pittii (one of 13) and a novel Acinetobacter species (one of 13). Class 1 integrons and bla_OXA-23-like were not detected. Isolates were susceptible to most antibiotics.

CONCLUSIONS AND CLINICAL IMPORTANCE

The study confirms that Acinetobacter spp. can survive on canine skin, where they may be potential reservoirs for infection. This highlights the importance of good hygiene in veterinary practice, adhering to aseptic principles in surgery, and treatment based on culture and susceptibility testing where possible.