Patterns and predictors of antimicrobial resistance among Staphylococcus spp. from canine clinical cases presented at a veterinary academic hospital in South Africa

Background Antimicrobial resistance in staphylococci, often associated with treatment failure, is increasingly reported in veterinary medicine. The aim of this study was to investigate patterns and predictors of antimicrobial resistance among Staphylococcus spp. isolates from canine samples submitted to the bacteriology laboratory at the University of Pretoria academic veterinary hospital between 2007 and 2012. Retrospective data of 334 Staphylococcus isolates were used to calculate the proportion of samples resistant to 15 antimicrobial agents. The Cochran-Armitage trend test was used to investigate temporal trends and logistic regression models were used to investigate predictors of antimicrobial resistance in Staphylococcus aureus and Staphylococcus pseudintermedius. Results Results show that 98.2% (55/56) of the S. aureus isolates were resistant to at least one drug while 42.9% were multidrug resistant. Seventy-seven percent (214/278) of the S. pseudintermedius isolates were resistant to at least one drug and 25.9% (72/278) were multidrug resistant. Resistance to lincospectin was more common among S. aureus(64.3%) than S. pseudintermedius (38.9%). Similarly, resistance to clindamycin was higher in S. aureus (51.8%) than S. pseudintermedius (31.7%) isolates. There was a significant (p = 0.005) increase in S. aureus resistance to enrofloxacin over the study period. Similarly, S. pseudintermedius exhibited significant increasing temporal trend in resistance to trimethoprim-sulphamethoxazole (p = 0.004), clindamycin (p = 0.022) and orbifloxacin (p = 0.042). However, there was a significant decreasing temporal trend in the proportion of isolates resistant to doxycycline (p = 0.041), tylosin (p = 0.008), kanamycin (p = 0.017) and amoxicillin/clavulanic acid (p = 0.032). Conclusions High levels of multidrug resistance and the increasing levels of resistance to sulphonamides, lincosamides and fluoroquinolones among Staphylococcus spp. isolates in this study are concerning. Future studies will need to investigate local drivers of antimicrobial resistance to better guide control efforts to address the problem

Antimicrobial resistance among Escherichia coli isolates from dogs presented with urinary tract infections at a veterinary teaching hospital in South Africa

Abstract Background This study investigated the burden and predictors of canine E. coli urinary tract infections (UTI) and antimicrobial resistance among dogs presented at a veterinary teaching hospital in South Africa, 2007–2012. Methods The Cochran-Armitage trend test was used to investigate temporal trends while logistic regression models were used to investigate predictors (age, sex, breed, year) of E. coli infections and antimicrobial resistance (AMR). Results A total of 22.3% (168/755) of the urinary specimens tested positive for E. coli. A significant (p = 0.0004) decreasing temporal trend in the percentage of E. coli positive isolates was observed over the study period. There were high levels of AMR to penicillin-G (99%), clindamycin (100%), tylosine (95%), cephalothin (84%) but relatively low levels of resistance to enrofloxacin (16%), orbifloxacin (21%). Almost all (98%, 164/167) the isolates exhibited multidrug resistance (MDR), while only 11% (19/167) and 2% (4/167) exhibited extensive drug resistance (XDR) and pan-drug resistance (PDR), respectively. Conclusions Although, the risk of E. coli UTI declined during the study period, the risk of AMR increased. The high levels of AMR and MDR as well as the presence of XDR and PDR is concerning as these have the potential of affecting prognosis of UTI treatments

Antimicrobial resistance patterns of Acinetobacter baumannii and Klebsiella pneumoniae isolated from dogs presented at a veterinary academic hospital in South Africa

Background and Aim: Acinetobacter baumannii and Klebsiella pneumoniae are opportunistic bacterial pathogens responsible for hospital-acquired infections in veterinary medicine. Infection with these bacteria always requires urgent antimicrobial therapy. However, there is no evidence of studies that have investigated the antimicrobial drug resistance profile of these organisms in a veterinary setting in South Africa. This study investigated the antimicrobial resistance (AMR) patterns of A. baumannii and K. pneumoniae from clinical specimens obtained from dogs presented at a veterinary academic hospital. The findings of this study contribute to an improved understanding of the AMR profile of these bacteria in veterinary medicine. Materials and Methods: Retrospective data of clinical samples from dogs that were positive for A. baumannii and K. pneumoniae between 2007 and 2013 were used in this study. The antimicrobial susceptibility of the isolates was determined using the disk diffusion method following the Clinical and Laboratory Standards Institute guidelines. The A. baumannii isolates were subjected to a panel of 20 antibiotics, while K. pneumoniae isolates were subjected to a panel of 22 antibiotics. Data were analyzed using descriptive statistics and presented using tables and figures. Results: Twenty (n = 20) A. baumannii isolates were isolated from bronchoalveolar lavage, foreign objects, bone, urine, skin, blood, ear, nasal, and oral cavity. Almost all A. baumannii (95%, 19/20) isolates were resistant to at least one antibiotic, and 60% (12/20) were multidrug-resistant (MDR). Klebsiella pneumoniae (n = 56) was isolated from urine, foreign objects, abscesses, ears, eyes, tracheal aspirations, bronchoalveolar lavages, eyes, abdominal aspirates, anal glands, bones, and intestinal and lung biopsies. All K. pneumoniae (100%, 56/56) isolates were resistant to at least one antibiotic, and 98% (55/56) were MDR. Conclusion: Both A. baumannii and K. pneumoniae were isolated in various clinical tissue samples and exhibited a high prevalence of resistance to multiple antibiotics. In addition, these bacteria exhibited a high prevalence of resistance to β-lactam compared to other classes of antibiotics, which is likely to impact treatment options and patient prognosis

An in vitro study on the potential of selected South African plant extracts to prevent and treat bovine mastitis

DATA AVAILABILIY: All research data in this study are provided in this manuscript.Mastitis is a painful inflammatory condition, commonly resulting from infections caused by Staphylococcus aureus and other pathogens. In this study, antimicrobial, anti-biofilm and anti-quorum sensing activities of selected plants were investigated against Staphylococcus aureus isolates from clinical cases of bovine mastitis. Acetone and ethanol extracts of 15 plants were initially screened for their antimicrobial activities against the commercially available reference strain S. aureus ATCC 29213. Maytenus undata, Maurocenia frangula, Kalanchoe gunniae and Bryophyllum pinnatum had good activities and extracts were tested against six multi-drug resistant S. aureus strains isolated from clinical bovine mastitis cases. The four plants were further analysed for cytotoxicity and anti-quorum sensing activities. Two of the plants with good results were assessed further for anti-biofilm activity. Minimum inhibitory concentration (MIC) values of the extracts against S. aureus isolates ranged from 0.02 to 0.63 mg/mL. Kalanchoe gunniae extracts were the least cytotoxic with extremely promising selectivity index (SI) values ranging from 12 to 25. Significant inhibition of biofilm development against S. aureus mastitis isolates was observed, but extracts were not able to eradicate pre-formed biofilms. Kalanchoe gunniae extracts had the best anti-quorum sensing activity with minimum quorum sensing inhibition concentration (MQSIC) and MIC values of 0.04 mg/mL and 0.63 mg/mL respectively against Chromobacterium violaceum ATCC 12472. Therefore, K. gunniae holds potential for development of a preventative treatment against bovine mastitis.The University of Pretoria.http://www.elsevier.com/locate/sajb2024-01-18hj2023Paraclinical SciencesProduction Animal Studie

Do pathogenic Escherichia coli isolated from Gallus gallus in South Africa carry co-resistance toward colistin and carbapenem antimicrobials?

Please read abstract in the article.The South African Medical Research Council, the University of Pretoria, and the South African National Research Foundation.https://home.liebertpub.com/publications/foodborne-pathogens-and-disease/108hj2023Paraclinical SciencesNon

Prevalence of colistin resistance and antibacterial resistance in commensal Escherichia coli from chickens an assessment of the impact of regulatory intervention in South Africa

DATA AVAILABILITY STATEMENT : The data that support the findings of this study are available from the corresponding author upon reasonable request.BACKGROUND : Antimicrobial resistance (AMR) is a global health problem largely due to the overuse of antimicrobials. In recognition of this, the World Health Assembly in 2015 agreed on a global action plan to tackle AMR. Following the global emergence of the mcr-1-associated colistin resistance gene in the livestock industry in 2016, several countries including South Africa restricted the veterinary use of colistin as the gene threatens the clinical utility of the drug. This study is a follow-up to the restriction in place in order to evaluate the impact of such policy adoption. OBJECTIVE : To assess the prevalence of antibacterial resistance (ABR), and the mcr-1 colistin resistance gene in broiler chicken over a 2-year period, as a follow-up to the veterinary ban on colistin use in South Africa. METHODS : A total of 520 swab samples were obtained during 2019 (March–April) and 2020 (February–March), from healthy broiler chicken carcasses (n = 20) and chicken droppings in transport crates (n = 20) at various poultry abattoirs (N = 7) in the Gauteng province of South Africa. Escherichia coli organisms were isolated and subjected to a panel of 24 antibacterials using the MicroScan machine. Screening for mcr-1 colistin resistance gene was undertaken using PCR. RESULTS : Four hundred and thirty-eight (438) E. coli strains were recovered and none demonstrated phenotypic resistance towards colistin, amikacin, carbapenems, tigecycline and piperacillin/tazobactam. The mcr-1 gene was not detected in any of the isolates tested. Resistances to the aminoglycosides (0%–9.8%) and fluoroquinolones (0%–18.9%) were generally low. Resistances to ampicillin (32%–39.3%) and trimethoprim/sulphamethoxazole (30.6%–3.6%) were fairly high. A significant (p < 0.05) increase in cephalosporins and cephamycin resistance was noted in the year 2020 (February–March) when compared with the year 2019 (March–April). CONCLUSION : The absence of mcr-1 gene and colistin resistance suggests that mitigation strategies adopted were effective and clearly demonstrated the significance of regulatory interventions in reducing resistance to critical drugs. Despite the drawback in regulatory framework such as free farmers access to antimicrobials OTC and a dual registration system in place, there is a general decline in the prevalence of ABR when the present data are compared with the last national veterinary surveillance on AMR (SANVAD 2007). To further drive resistance down, mitigation strategies should focus on strengthening regulatory framework, the withdrawal of OTC dispensing of antimicrobials, capping volumes of antimicrobials, banning growth promoters and investing on routine surveillance/monitoring of AMR and antimicrobial consumption.The South African Medical Research Council, the University of Pretoria, and the South African National Research Foundation.https://wileyonlinelibrary.com/journal/vms3hj2023Paraclinical SciencesNon

Burden and predictors of Staphylococcus aureus and S. pseudintermedius infections among dogs presented at an academic veterinary hospital in South Africa (2007–2012)

Background Staphylococci are commensals of the mucosal surface and skin of humans and animals, but have been implicated in infections such as otitis externa, pyoderma, urinary tract infections and post-surgical complications. Laboratory records provide useful information to help investigate these infections. Therefore, the objective of this study was to investigate the burdens of these infections and use multinomial regression to examine the associations between various Staphylococcus infections and demographic and temporal factors among dogs admitted to an academic veterinary hospital in South Africa. Methods Records of 1,497 clinical canine samples submitted to the bacteriology laboratory at a veterinary academic hospital between 2007 and 2012 were included in this study. Proportions of staphylococcal positive samples were calculated, and a multinomial logistic regression model was used to identify predictors of staphylococcal infections. Results Twenty-seven percent of the samples tested positive for Staphylococcusspp. The species of Staphylococcus identified were S. pseudintermedius(19.0%), S. aureus (3.8%), S. epidermidis (0.7%) and S. felis (0.1%). The remaining 2.87% consisted of unspeciated Staphylococcus. Distribution of the species by age of dog showed that S. pseudintermedius was the most common (25.6%) in dogs aged 2–4 years while S. aureus was most frequent (6.3%) in dogs aged 5–6 years. S. pseudintermedius (34.1%) and S. aureus(35.1%) were the most frequently isolated species from skin samples. The results of the multivariable multinomial logistic regression model identified specimen, year and age of the dog as significant predictors of the risk of infection with Staphylococcus. There was a significant temporal increase (RRR = 1.17; 95% CI [1.06–1.29]) in the likelihood of a dog testing positive for S. pseudintermedius compared to testing negative. Dogs ≤ 8 years of age were significantly more likely to test positive for S. aureus than those \u3e8 years of age. Similarly, dogs between 2–8 years of age were significantly more likely to test positive for S. pseudintermedius than those \u3e8 years of age. In addition, dogs 2–4 years of age (RRR = 1.83; 1.09–3.06) were significantly more likely to test positive for S. pseudintermedius compared to those S. pseudintermedius or S. aureus was significantly higher in ear canal and skin specimens compared to other specimens. Conclusions The findings suggest that S. pseudintermedius and S. aureus were the most commonly isolated species from dogs presented at the study hospital. Age of the dog and the location of infection were significant predictors of infection with both Staphylococcus species investigated. Significant increasing temporal trend was observed for S. pseudintermedius but not S. aureus. This information is useful for guiding clinical decisions as well as future research

The molecular epidemiology and antimicrobial resistance of Staphylococcus pseudintermedius canine clinical isolates submitted to a veterinary diagnostic laboratory in South Africa

Staphylococcus pseudintermedius is an important cause of clinical infections in small-animal-veterinary medicine. Evolutionary changes of strains using multilocus sequence typing (MLST) have been observed among S. pseudintermedius in European countries and the United States. However, there are limited or no studies on the detection of methicillin resistant Staphylococcus pseudintermedius (MRSP) and predominating MLST strains in South Africa. Therefore, this study aimed to determine the molecular epidemiology of S. pseudintermedius in South Africa. Twenty-six, non-duplicate, clinical isolates from dogs were obtained as convenience samples from four provinces in South Africa. The Kirby Bauer disk diffusion test was used to determine antimicrobial susceptibility. We used Resfinder and the Comprehensive Antibiotic Resistance Database (CARD) to detect antimicrobial resistance genes. Virulence genes were identified using the virulence factor database and Basic Local Alignment Search Tool (BLASTN) on Geneious prime. geoBURST analysis was used to study relationships between MLST. Finally, the maximum likelihood phylogeny was determined using Randomized Axelerated Maximum Likelihood (RAxML). Twenty-three isolates were confirmed as S. pseudintermedius of which 14 were MRSP. In addition to β-lactam antimicrobials, MRSP isolates were resistant to tetracycline (85.7%), doxycycline (92.8%), kanamycin (92.8%), and gentamicin (85.7%). The isolates harbored antimicrobial resistance genes (tetM, ermB, drfG, cat, aac(6’)-Ie-aph(2”)-Ia, ant(6)-Ia, and aph(3’)-III) and virulence genes (AdsA, geh, icaA, and lip). MLST analysis showed that ST2228, ST2229, ST2230, ST2231, ST2232, ST2318, ST2326 and ST2327 are unique sequence types in South Africa. Whereas, previously reported major STs including ST45, ST71, ST181, ST551 and ST496 were also detected. The geoBURST and phylogenetic analysis suggests that the isolates in South Africa are likely genetically related to isolates identified in other countries. Highly resistant MRSP strains (ST496, ST71, and ST45) were reported that could present challenges in the treatment of canine infections in South Africa. Hence, we have gained a better understanding of the epidemiology of MRSP in the African continent, the genes involved in resistance and virulence factors associated with these organisms