scholarly journals Antimicrobial Resistance Phenotypic Profile of Isolates from Clinical Infections in Dogs

2017 ◽  
Vol 45 (1) ◽  
pp. 8
Author(s):  
Ricardo Antonio Pilegi Sfaciotte ◽  
Lincoln Garcia Coronel ◽  
Alessandra Snak ◽  
Jéssica Tainá Bordin ◽  
Paula Wildemann ◽  
...  
Keyword(s):  
Veterinary Medicine ◽  
Antimicrobial Resistance ◽  
Antimicrobial Agent ◽  
Companion Animals ◽  
Multidrug Resistant ◽  
Cross Resistance ◽  
Resistant Bacteria ◽  
Gram Positive ◽  
Enterococcus Spp ◽  
Staphylococcus Spp

Background: Antimicrobial resistance is described as a condition in which a micro-organism is able to survive when exposed to an antimicrobial agent. The resistance rates to antimicrobials in companion animals have risen considerably. Studies of local antimicrobial susceptibility profiles are needed as well as education and warning about the use of tests for the identification and susceptibility of pathogenic bacterial strains. The aim of this study was to identify the main antimicrobial resistance in clinical samples of dogs, and to detect multidrug-resistant strains of importance to public health.Materials, Methods & Results: Bacterial pathogens of 77 dog infections were isolated and their sensitivity profile to antimicrobials was determined. One hundred bacterial isolates were identified. Of these, 61 were Gram-positive (55 Staphylococcus spp., 4 Enterococcus spp. and 2 Streptococcus spp.) and 39 Gram-negative (36 fermenters and 3 non-fermenters). Seventy-nine isolates were considered multiresistant following individual assessment of drugs, and 85 following the evaluation of classes. Only 3 were sensitive to all drugs. Four isolates were resistant to all classes and only sensitive to some antibiotics. Of the 55 samples of Staphylococcus spp., 36 (65.45%) were identified as phenotypically MRS. Two isolates of Enterococcus spp. were resistant to vancomycin (VRE). Also 66.67% (26/39) of the samples were positive for the presumptive test for ESBL. For the MRS-positive isolates detected in this study, chloramphenicol was the antimicrobial that showed superior sensitivity in 74.29% of the cases (27/36); therefore it is considered the most appropriate for treatment of this type of micro-organism. In case of aminoglycosides, when their resistance was checked in MRS isolates, all resistance percentages increased, implying a limited use of this class for such a type of multi-resistant micro-organism. Contrarily, in case of ESBL, a superior sensitivity was observed towards MRS isolates, thus making them a prime treatment choice for the infection caused by these micro-organisms.Discussion: Literature have reported a gradual increase in multidrug resistance towards antimicrobial agents in veterinary medicine over the past decades. In this study, 64% of multiresistant strains were considered of significant importance, notably MRS (36), VRE (2) and ESBL (26). The early identification of pathogens in animals has become an important step in order to minimize the transmission of antibacterial resistance. The increase in the number of multidrug-resistant bacteria in animals and humans demonstrates the need to develop and implement measures in order to monitor and control the spread of this resistance. It is possible that the increased drug resistance is linked to the constant exposure to these drugs and the subsequent selective pressure, causing the transfer of resistant genes between strains. Carbapenems and glycopeptides should be used with caution in veterinary medicine in order to prevent such processes of selection that develop resistance in micro-organisms to these two classes, which can result in cross-resistance between animals and humans and create obstacles in the treatment of patients, especially for the two drugs mentioned, since they are important for the treatment of nosocomial infections in humans. The resistance percentage towards fluoroquinolones was identified to be higher in Gram-positive isolates, particularly in MRS, which showed 75% resistance against this class (according to the CLSI, resistance to one fluoroquinolone antimicrobial agent provides resistance to other antimicrobials of this class). For ESBL isolates, the resistance was shown to be 50%. The resistance towards the fluoroquinolones and aminoglycosides class can be associated with the expression of the genes that produce ESBL.

scholarly journals Rethinking Manure Application: Increase in Multidrug-Resistant Enterococcus spp. in Agricultural Soil Following Chicken Litter Application

2021 ◽  
Vol 9 (5) ◽  
pp. 885
Author(s):  
Dorcas Oladayo Fatoba ◽  
Akebe Luther King Abia ◽  
Daniel G. Amoako ◽  
Sabiha Y. Essack
Keyword(s):  
Antimicrobial Resistance ◽  
Agricultural Soil ◽  
Multidrug Resistant ◽  
Diffusion Method ◽  
Resistant Bacteria ◽  
Manure Application ◽  
Unamended Soil ◽  
Enterococcus Spp ◽  
Chicken Litter ◽  
Amended Soil

The current study investigated the impact of chicken litter application on the abundance of multidrug-resistant Enterococcus spp. in agricultural soil. Soil samples were collected from five different strategic places on a sugarcane farm before and after manure application for four months. Chicken litter samples were also collected. Enterococci were enumerated using the Enterolert®/Quanti-Tray 2000® system and confirm and differentiated into species using real-time PCR. The antibiotic susceptibility profile of the isolates was determined using the disk diffusion method following the European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. The overall mean bacterial count was significantly higher (p < 0.05) in manure-amended soil (3.87 × 107 MPN/g) than unamended soil (2.89 × 107 MPN/g). Eight hundred and thirty-five enterococci (680 from soil and 155 from litter) were isolated, with E. casseliflavus being the most prevalent species (469; 56.2%) and E. gallinarum being the least (16; 1.2%). Approximately 56% of all the isolates were resistant to at least one antibiotic tested, with the highest resistance observed against tetracycline (33%) and the lowest against chloramphenicol (0.1%); 17% of E. faecium were resistant to quinupristin-dalfopristin. Additionally, 27.9% (130/466) of the isolates were multidrug-resistant, with litter-amended soil harbouring more multidrug-resistant (MDR) isolates (67.7%; 88/130) than unamended soil (10.0%; 13/130). All isolates were susceptible to tigecycline, linezolid and gentamicin. About 7% of the isolates had a multiple antimicrobial resistance index > 0.2, indicative of high antibiotic exposure. Although organic fertilizers are regarded as eco-friendly compared to chemical fertilizers for improving soil fertility, the application of untreated animal manure could promote the accumulation of antibiotics and their residues and antibiotic-resistant bacteria in the soil, creating an environmental reservoir of antimicrobial resistance, with potential human and environmental health risks.

scholarly journals Identification and resistance profile of gram positive bacteria from aquatic environment

2021 ◽  
Vol 10 (13) ◽  
pp. e226101321182
Author(s):  
Thais Reis Oliveira ◽  
Raylane Pereira Gomes ◽  
Ariadne Bernardes Rodrigues ◽  
Leandro Martins Ferreira ◽  
Aline Rodrigues Gama ◽  
...  
Keyword(s):  
Aquatic Environment ◽  
Multidrug Resistant ◽  
The Other ◽  
Raw Water ◽  
Gram Positive ◽  
Resistance Profile ◽  
Gram Positive Bacteria ◽  
Enterococcus Spp ◽  
Bacillus Spp ◽  
Staphylococcus Spp

The Meia Ponte River – Goiás/Brazil, is responsible for benefiting about 2 million people in Goiás State. However, the increase in pollution with the disposal of sewage, chemicals and drug remains have contributed to the increase in bacterial resistance and the exchange of resistance genes. The objective of this study was to isolate, identify and analyze the resistance profile of gram-positive bacteria present in raw water and sediment of the Meia Ponte River – Goiás. The samples were collected from four sampling points and two collections were carried out, one in the dry season and the other in the rainy season. The isolated bacteria were identificated, then the antibiogram was performed. A total of 75 strains were isolated, 72.0% (54/75) of Streptococcus spp., 12.0% (9/75) of Staphylococcus spp., 9.3% (7/75) of Bacillus spp. and 6.7% (5/75) of Enterococcus spp. Furthermore, 52.0% (39/75) of the isolated strains were from raw water and 48.0% (36/75) were isolated from the sediment. Among the samples, strains of Staphylococcus spp. and Bacillus spp. showed greater resistance to antimicrobials, on the other hand, Enterococcus spp. showed less resistance. Some strains of Bacillus spp. and Streptococcus spp. presented multidrug resistant, Staphylococcus spp. showed multidrug resistant and some pan-drug resistant. In the correlation of Spearman Staphylococcus spp. and Streptococcus spp. isolated, were the ones that presented the most significant correlations (p < 0.05). Thus, the study shows the importance of ascertaining the resistance profile of this group of bacteria that aquatic environment.

scholarly journals Patterns of Antimicrobial Resistance Observed in Escherichia coli Isolates Obtained from Domestic- and Wild-Animal Fecal Samples, Human Septage, and Surface Water

2005 ◽  
Vol 71 (3) ◽  
pp. 1394-1404 ◽  
Author(s):  
Raida S. Sayah ◽  
John B. Kaneene ◽  
Yvette Johnson ◽  
RoseAnn Miller
Keyword(s):  
Escherichia Coli ◽  
Surface Water ◽  
Antimicrobial Resistance ◽  
Antimicrobial Agent ◽  
Companion Animals ◽  
Diffusion Method ◽  
Resistant Bacteria ◽  
Isolation And Identification ◽  
Fecal Samples ◽  
E Coli

ABSTRACT A repeated cross-sectional study was conducted to determine the patterns of antimicrobial resistance in 1,286 Escherichia coli strains isolated from human septage, wildlife, domestic animals, farm environments, and surface water in the Red Cedar watershed in Michigan. Isolation and identification of E. coli were done by using enrichment media, selective media, and biochemical tests. Antimicrobial susceptibility testing by the disk diffusion method was conducted for neomycin, gentamicin, streptomycin, chloramphenicol, ofloxacin, trimethoprim-sulfamethoxazole, tetracycline, ampicillin, nalidixic acid, nitrofurantoin, cephalothin, and sulfisoxazole. Resistance to at least one antimicrobial agent was demonstrated in isolates from livestock, companion animals, human septage, wildlife, and surface water. In general, E. coli isolates from domestic species showed resistance to the largest number of antimicrobial agents compared to isolates from human septage, wildlife, and surface water. The agents to which resistance was demonstrated most frequently were tetracycline, cephalothin, sulfisoxazole, and streptomycin. There were similarities in the patterns of resistance in fecal samples and farm environment samples by animal, and the levels of cephalothin-resistant isolates were higher in farm environment samples than in fecal samples. Multidrug resistance was seen in a variety of sources, and the highest levels of multidrug-resistant E. coli were observed for swine fecal samples. The fact that water sample isolates were resistant only to cephalothin may suggest that the resistance patterns for farm environment samples may be more representative of the risk of contamination of surface waters with antimicrobial agent-resistant bacteria.

scholarly journals Multidrug-Resistant Escherichia coli, Klebsiella pneumoniae and Staphylococcus spp. in Houseflies and Blowflies from Farms and Their Environmental Settings

2019 ◽  
Vol 16 (19) ◽  
pp. 3583 ◽  
Author(s):  
Anil Poudel ◽  
Terri Hathcock ◽  
Patrick Butaye ◽  
Yuan Kang ◽  
Stuart Price ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Klebsiella Pneumoniae ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Coagulase Negative Staphylococcus ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Antimicrobial Resistance Genes ◽  
Staphylococcus Spp

Background: Antimicrobial resistance is rising globally at an alarming rate. While multiple active surveillance programs have been established to monitor the antimicrobial resistance, studies on the environmental link to antimicrobial spread are lacking. Methods: A total of 493 flies were trapped from a dairy unit, a dog kennel, a poultry farm, a beef cattle unit, an urban trash facility and an urban downtown area to isolate Escherichia coli, Klebsiella pneumoniae and Staphylococcus spp. for antimicrobial susceptibility testing and molecular characterization. Results: E. coli, K. pneumoniae and coagulase-negative Staphylococcus were recovered from 43.9%, 15.5% and 66.2% of the houseflies, and 26.0%, 19.2%, 37.0% of the blowflies, respectively. In total, 35.3% of flies were found to harbor antimicrobial-resistant bacteria and 9.0% contained multidrug-resistant isolates. Three Staphylococcus aureus isolates were recovered from blowflies while three extended spectrum beta lactamase (ESBL)-carrying E. coli and one ESBL-carrying K. pneumoniae were isolated from houseflies. Whole genome sequencing identified the antimicrobial resistance genes blaCMY-2 and blaCTXM-1 as ESBLs. Conclusion: Taken together, our data indicate that flies can be used as indicators for environmental contamination of antimicrobial resistance. More extensive studies are warranted to explore the sentinel role of flies for antimicrobial resistance.

scholarly journals Profile of antimicrobial resistance in oncologic pediatric patients

2014 ◽  
Vol 2 (4) ◽  
Author(s):  
Mauricio García-Luna ◽  
José Antonio Madrid Gómez-Tagle ◽  
Jessica P. O’Brien
Keyword(s):  
Antimicrobial Resistance ◽  
Lymphoblastic Leukemia ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Development Of Resistance ◽  
Drug Resistant Bacteria ◽  
Clinical Records

The development of resistance to antibiotics is due to the widespread use of a wide variety of antimicrobials, coupled with the ability of bacteria to acquire and spread resistance and the ability of humans to disseminate them. The possible consequences of antimicrobial resistance leads to greater chances of hospitalization, prolongation of hospital stay and increased mortality. Furthermore, treatment of drug resistant bacteria requires the use of more toxic drugs and more expense for the patient and hospitals. The main objective of the present study was to determine the frequency and nature of antimicrobial resistance of microorganisms in oncologic and hematologic patients at a Mexican Pediatric Hospital. A retrospective, observational, and analytical study was realized, where we reviewed the clinical records of 20 cases. Blood cultures were obtained from the Laboratory of our institution from 2010 to 2011. The data obtained were organized and analyzed. We observed that the E. coli and S. aureus were the bacteria most resistant, showing the same percentage between gram-positive and gram-negative bacteria. The cancer diagnosis most common in our study was acute lymphoblastic leukemia. It may be concluded that multidrug-resistant bacteria in these patients are of a nosocomial origin, without a specific group of germ (gram positive vs. gram negative).

scholarly journals Liposomes as Antibiotic Delivery Systems: A Promising Nanotechnological Strategy against Antimicrobial Resistance

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2047
Author(s):  
Magda Ferreira ◽  
Maria Ogren ◽  
Joana N. R. Dias ◽  
Marta Silva ◽  
Solange Gil ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Bacterial Infections ◽  
Private Investment ◽  
Therapeutic Index ◽  
Multidrug Resistant ◽  
Current Treatment ◽  
Delivery Systems ◽  
Resistant Bacteria ◽  
Bacterial Cells ◽  
Antimicrobial Drugs

Antimicrobial drugs are key tools to prevent and treat bacterial infections. Despite the early success of antibiotics, the current treatment of bacterial infections faces serious challenges due to the emergence and spread of resistant bacteria. Moreover, the decline of research and private investment in new antibiotics further aggravates this antibiotic crisis era. Overcoming the complexity of antimicrobial resistance must go beyond the search of new classes of antibiotics and include the development of alternative solutions. The evolution of nanomedicine has allowed the design of new drug delivery systems with improved therapeutic index for the incorporated compounds. One of the most promising strategies is their association to lipid-based delivery (nano)systems. A drug’s encapsulation in liposomes has been demonstrated to increase its accumulation at the infection site, minimizing drug toxicity and protecting the antibiotic from peripheral degradation. In addition, liposomes may be designed to fuse with bacterial cells, holding the potential to overcome antimicrobial resistance and biofilm formation and constituting a promising solution for the treatment of potential fatal multidrug-resistant bacterial infections, such as methicillin resistant Staphylococcus aureus. In this review, we aim to address the applicability of antibiotic encapsulated liposomes as an effective therapeutic strategy for bacterial infections.

scholarly journals Prevalence of Antimicrobial Resistant Bacteria from Conjunctival Flora in an Eye Infection Prone Breed (Saint Bernard)

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2219
Author(s):  
George Cosmin Nadăș ◽  
Cristiana Ștefania Novac ◽  
Ioana Adriana Matei ◽  
Cosmina Maria Bouari ◽  
Zoltan Miklos Gal ◽  
...  
Keyword(s):  
Multidrug Resistant ◽  
Ocular Disease ◽  
Resistant Bacteria ◽  
Human Populations ◽  
Disease Treatment ◽  
Pseudomonas Spp ◽  
History Of ◽  
External Sources ◽  
Staphylococcus Spp ◽  
Saint Bernard

The conjunctival bacterial resident and opportunistic flora of dogs may represent a major source of dissemination of pathogens throughout the environment or to other animals and humans. Nevertheless, contamination with bacteria from external sources is common. In this context, the study of the antimicrobial resistance (AMR) pattern may represent an indicator of multidrug resistant (MDR) strains exchange. The present study was focused on a single predisposed breed—Saint Bernard. The evaluated animals were healthy, but about half had a history of ocular disease/treatment. The swabs collected from conjunctival sacs were evaluated by conventional microbiological cultivation and antimicrobial susceptibility testing (AST). The most prevalent Gram-positive was Staphylococcus spp.; regardless of the history, while Gram-negative was Pseudomonas spp.; exclusively from dogs with a history of ocular disease/treatment. Other identified genera were represented by Bacillus, Streptococcus, Trueperella, Aeromonas and Neisseria. The obtained results suggest a possible association between the presence of mixed flora and a history of ocular disease/treatment. A high AMR was generally observed (90%) in all isolates, especially for kanamycin, doxycycline, chloramphenicol and penicillin. MDR was recorded in Staphylococcus spp. and Pseudomonas spp. This result together with a well-known zoonotic potential may suggest an exchange of these strains within animal human populations and the environment.

scholarly journals Technologies to address antimicrobial resistance

2018 ◽  
Vol 115 (51) ◽  
pp. 12887-12895 ◽  
Author(s):  
Stephen J. Baker ◽  
David J. Payne ◽  
Rino Rappuoli ◽  
Ennio De Gregorio
Keyword(s):  
Antimicrobial Resistance ◽  
Bacterial Infections ◽  
Membrane Vesicles ◽  
Multidrug Resistant ◽  
Outer Membrane Vesicles ◽  
Resistant Bacteria ◽  
Multiple Stakeholders ◽  
Global Challenge ◽  
Life Threatening ◽  
Bacterial Outer Membrane

Bacterial infections have been traditionally controlled by antibiotics and vaccines, and these approaches have greatly improved health and longevity. However, multiple stakeholders are declaring that the lack of new interventions is putting our ability to prevent and treat bacterial infections at risk. Vaccine and antibiotic approaches still have the potential to address this threat. Innovative vaccine technologies, such as reverse vaccinology, novel adjuvants, and rationally designed bacterial outer membrane vesicles, together with progress in polysaccharide conjugation and antigen design, have the potential to boost the development of vaccines targeting several classes of multidrug-resistant bacteria. Furthermore, new approaches to deliver small-molecule antibacterials into bacteria, such as hijacking active uptake pathways and potentiator approaches, along with a focus on alternative modalities, such as targeting host factors, blocking bacterial virulence factors, monoclonal antibodies, and microbiome interventions, all have potential. Both vaccines and antibacterial approaches are needed to tackle the global challenge of antimicrobial resistance (AMR), and both areas have the underpinning science to address this need. However, a concerted research agenda and rethinking of the value society puts on interventions that save lives, by preventing or treating life-threatening bacterial infections, are needed to bring these ideas to fruition.

scholarly journals Retail Chicken Carcasses as a Reservoir of Antimicrobial- Resistant Escherichia coli

2020 ◽  
Author(s):  
Nahla Omer Eltai ◽  
Hadi M. Yassine ◽  
Sara H. Al-Hadidi ◽  
Tahra ElObied ◽  
Asmaa A. Al Thani ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Growth Promotion ◽  
Multidrug Resistant ◽  
Chicken Meat ◽  
Resistant Bacteria ◽  
Antibiotic Resistant ◽  
E Coli ◽  
Inappropriate Use ◽  
Esbl Producers

The dissemination of antimicrobial resistance (AMR) bacteria has been associated with the inappropriate use of antibiotics in both humans and animals and with the consumption of food contaminated with resistant bacteria. In particular, the use of antibiotics as prophylactic and growth promotion purposes in food-producing animals has rendered many of the antibiotics ineffective. The increased global prevalence of AMR poses a significant threat to the safety of the world’s food supply. Objectives: This study aims at determining the prevalence of antibiotic-resistant Escherichia coli (E. coli) isolated from local and imported retail chicken meat in Qatar. Methodology: A total of 270 whole chicken carcasses were obtained from three different hypermarket stores in Qatar. A total of 216 E. coli were isolated and subjected to antibiotic susceptibility testing against 18 relevant antibiotics using disc diffusion and micro- dilution methods. Furthermore, extended-spectrum β-lactamase (ESBL) production was determined via a double-disc synergetic test. Isolates harboring colistin resistance were confirmed using multiplex-PCR and DNA sequencing. Results: Nearly 89% (192/216) of the isolates were resistant to at least one antibiotics. In general, isolates showed relatively higher resistance to sulfamethoxazole (62%), tetracycline (59.7%), ampicillin and trimethoprim (52.3%), ciprofloxacin (47.7%), cephalothin, and colistin (31.9%). On the other hand, less resistance was recorded against amoxicillin/clavulanic acid (6%), ceftriaxone (5.1%), nitrofurantoin (4.2%) and piperacillin/tazobactam (4.2%), cefepime (2.3%), meropenem (1.4%), ertapenem (0.9%), and amikacin (0.9%). Nine isolates (4.2%) were ESBL producers. Furthermore, 63.4% were multidrug-resistant (MDR). The percentage of MDR, ESBL producers, and colistin-resistant isolates was significantly higher among local isolates compared to imported chicken samples. Conclusion: We reported a remarkably high percentage of the antibiotic-resistant E. coli in chicken meat sold at retail in Qatar. The high percentage of MDR and colistin isolates is troublesome to the food safety of raw chicken meat and the potential of antibiotic resistance spread to public health. Our findings support the need for the implementation of one health approach to address the spread of antimicrobial resistance and the need for a collaborative solution.

scholarly journals Phenotypic and Genotypic Characteristics and Resistance Profile of Staphylococcus spp. from Bovine Mastitis

2020 ◽  
Vol 48 ◽  
Author(s):  
Érica Chaves Lucio ◽  
Gisele Veneroni Gouveia ◽  
Mateus Matiuzzi Da Costa ◽  
Mário Baltazar De Oliveira ◽  
Rinaldo Aparecido Mota ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Milk Production ◽  
Biofilm Formation ◽  
Negative Impact ◽  
Meca Gene ◽  
Bovine Mastitis ◽  
Resistant Bacteria ◽  
Production Chain ◽  
Biofilm Production ◽  
Staphylococcus Spp

Background: Bovine mastitis remains one of the health problems that cause the most damage to milk producers. The negative impact of mastitis is due to reduced milk production, early slaughter of females, reduced commercial value of the affected animals, losses in the genetic potential of the herd, expenses with medicines and veterinary medical assistance. Staphylococcus spp. stands out as the cause of this disease and has been able to remain in the mammary gland, becoming resistant to several antimicrobials. The aims of the present study were to characterize the phenotypes, genotypes and resistance profiles of Staphylococcus spp. isolates from bovine mastitis cases in the state of Pernambuco, Brazil.Materials, Methods & Results: These isolates were classified according to biochemical tests and the presence of the nuc gene.  The polymerase chain reaction (PCR) for amplification of the mecA and blaZ genes was used to analyze the genetic potentials of antimicrobial resistance. Isolates were also phenotypically tested for resistance to nine antimicrobials (ampicillin, doxicillin, erythromycin, gentamicin, rifampicin, cephalothin, amoxicillin, nalidixic acid and oxacillin). The genetic potentials for biofilm production were evaluated by the amplifications of the icaD, icaA and bap genes. The phenotypic test of gentian violet was used for biofilm formation analyzes. Ninety-three (93.0%) of the isolates among the Staphylococcus spp. samples were classified as Staphylococcus aureus. The lowest percentage of sensitivity observed was for amoxicillin (28.0%). All of the isolates were sensitive to erythromycin and gentamicin, and 15 (15%) exhibited sensitivity to all of the drugs tested. All of the isolates were negative for the mecA gene, and 36 (36%) were positive for blaZ. In the adhesion microplate tests, 44 (44%) of the isolates were capable of biofilm formation. Of these, seven (15.9%) were strong formers, whereas 16 (36.3%) and 21 (47.8%) were moderate and weak formers, respectively. The icaD gene was confirmed in 89 (89%) of the isolates. The icaA gene was confirmed in 61 (61%) samples, and the bap gene in 52 (52%) samples. One of the samples did not possess icaA, icaD or bap and exhibited moderate biofilm formation according to the microplate adherence test. Sixteen isolates simultaneously exhibited the three genes tested for biofilm production (icaA, icaD and bap) and were negative according to the microplate adherence test.Discussion:  The indiscriminate use of antibiotics to treat mastitis is a common practice in the study area, which may have contributed to the high proportion of herds (88.23%; 15/17) with multi-resistant isolates, constituting a selection factor for the dissemination of resistant bacteria among herds.  The absence of the mecA gene in the present study may be associated with the development of resistant bacteria through another mechanism, such as the overproduction of beta-lactamases. The results demonstrate that antimicrobial resistance occurs in Staphylococcus spp. that cause bovine mastitis in herds of Pernambuco and that these isolates have the a great capacity for biofilm formation. It is necessary to sensitize the professionals involved in the milk production chain of Brazil regarding the importance of the adequate use of antimicrobials for the treatment and control of mastitis, since studies in the country indicate the dissemination of resistant bacterial strains.

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