Objective:To investigate the prevalence of methicillin-resistant staphylococci(MRS)which is a potencial risk factor of transmission between animals and humans in different types of horses(harness racing-horses,breedin...Objective:To investigate the prevalence of methicillin-resistant staphylococci(MRS)which is a potencial risk factor of transmission between animals and humans in different types of horses(harness racing-horses,breeding mares and riding-horses)and to compare the antimicrobial resistance of the isolates.Methods:A total of 191 healthy horses,housed at different locations of the Campania Region(Italy),were included in the study.Nasal swab samples were collected from each nostril of the horses.The mecA gene was detected by a nested PCR technique.Antibiotic susceptibility was tested for each isolate.Results:MRS was isolated from nasal samples of 68/191(35.6%;95%CI:28.9%-42.9%)healthy horses.All isolates were coagulase-negative with the exception of two coagulase-positive MRS strains,identified as Staphylococcus aureus and Staphylococcus pseudintermedius.2/83(2.4%;95%,CI:0.4%-9.2%).Interestingly,both coagulase-positive MRS isolates were from harness racing-horses.These horses also presented a significantly higher positivity for MRS(53.3%;95%CI:40.1%-66.1%)than the breeding mares and riding-horses groups.Antibiotic susceptibility testing showed difference between isolates due to different origins except for an almost common high resistance to aminopenicillins,such as ampicillin and amoxicillin.Conclusions:It can be concluded that harness racing-horses may act as a significant reservoir of MRS as compared to breeding mares and riding-horses.展开更多
The coagulase-negative staphylococci (CoNS) group was considered saprophytic or rarely pathogenic for many years. Since the first case of septicemia caused by CoNS, there has been a progressive increase in the prevale...The coagulase-negative staphylococci (CoNS) group was considered saprophytic or rarely pathogenic for many years. Since the first case of septicemia caused by CoNS, there has been a progressive increase in the prevalence of healthcare-associated infections caused by CoNS. The CoNS group has emerged as one of the main causes of nosocomial infections related to vascular catheters and prostheses, especially among immunocompromised patients. This gradual increase in infections is due to the change in the relationship between patients and procedures since CoNS are closely related to devices implanted in the human body. CoNS are successful in colonizing the host because they have several virulence mechanisms, such as biofilm formation and production of enzymes and toxins, in addition to several mechanisms of resistance to antimicrobials. Despite their great clinical relevance, few studies have focused on CoNS’s pathogenicity and resistance to antimicrobials, which reveals the current need to better understand the factors by which this group became pathogenic to humans and other animals. This review aims to synthesize the aspects related to the pathogenicity and antimicrobial resistance in CoNS.展开更多
Staphylococci strains, like the majority of bacterial strains, have developed the resistance to several antibiotics, including Quinolones and Fluoroquin-olones In the Republic of the Congo, cases of resistance leading...Staphylococci strains, like the majority of bacterial strains, have developed the resistance to several antibiotics, including Quinolones and Fluoroquin-olones In the Republic of the Congo, cases of resistance leading to treat-ment failures have been observed during the treatment of staphylococcal infections with antibiotics in hospitals. The objective of this study was to identify the Quinolone/Fluoroquinolone resistance genes from staphylo-cocci strains isolated in hospitals. A total of 51 strains of Staphylococci were isolated, including 16 (31.37%) community strains, and 35 (68.62%) clinical strains. 46 strains of Staphylococcus aureus (S. aureus) and 5 SCNs were identified. A total of 34 DNA fragments from different strains resistant to Quinolones/Fluoroquinolones, including 21 (61.67%) DNA fragments from clinical S. aureus and 13 (38.23%) from community SCN strains were analyzed by the molecular method (genotypic detection) by PCR. The genotypic results made it possible to identify the gyrA, grLA and norA genes and to show that these genes are involved in the resistance of the strains to the various antibiotics used. The grLA gene was the most identified gene with a frequency of 75%. The gyrA and grLA genes have been identified in Staphylococcus aureus and Coagulase Negative Staphy-lococci. The norA gene, on the other hand, has only been identified in Staphylococcus aureus. Two mechanisms are essentially involved in the resistance of Staphylococci to quinolones/Fluoroquinolones, the mecha-nism of resistance by efflux, which takes place thanks to a transmembrane protein coded by the norA gene and by point mutations (substitution and deletion of acids or nucleotides) observed within the protein and nucleic sequences of the chromosomal gyrA and grLA genes.展开更多
The pathogenic effect of Staphylococci is due to extra-cellular factors and properties such as adherence and biofilm production. The nature of the biofilm and the physiological properties of biofilm-producing bacteria...The pathogenic effect of Staphylococci is due to extra-cellular factors and properties such as adherence and biofilm production. The nature of the biofilm and the physiological properties of biofilm-producing bacteria result in an inherent antibiotic resistance and require further investigation. Two hundred and sixty Staphylococcal strains were cultured from 600 clinical specimens obtained from hospitalized patients. Among these, 155 were identified as coagulase-positive (CPS) and 105 as coagulase-negative (CNS) staphylococci. Staphylococcal strains were tested for biofilm production using the tissue culture plate (TCP) method. TCP detection showed that of the 155 CPS, 124 (80%) were biofilm producers, while 63 (60%) of the 105 CNS were biofilm producers. Biofilm-producing strains were scanned by scanning electron microscope (SEM) to confirm biofilm formation, study biofilm production, and examine antibiotic effects on biofilm formation. Disc diffusion method was used to study resistance of planktonic and biofilm-forming cells to antibiotics. Planktonic cells were less resistant to antibiotics than biofilm-forming cells. Microbroth dilution method and a new BioTimer assay were used to determine antibiotic MICs affecting planktonic and biofilm cells. Both methods showed that the MICs for planktonic cells were less than that for biofilm cells. The BioTimer assay was therefore found to be sensitive, accurate, and reliable, with results in agreement with those from the broth dilution method and SEM.展开更多
Emerging antimicrobial resistance among CNS is a concern in veterinary and human medicine. Coagulase test is considered as the key test to differentiate staphylococci to two groups, coagulase positive staphylococci (C...Emerging antimicrobial resistance among CNS is a concern in veterinary and human medicine. Coagulase test is considered as the key test to differentiate staphylococci to two groups, coagulase positive staphylococci (CPS) and coagulase negative staphylococci (CNS). A total of 200?Staphylococci?strains were isolated with percentage 66.7% (200/300) from quarter milk samples. The total of?S. aureus?strains are 70 with percentage 35% (70/200). Among 70 strains of?S. aureus, 30 strains are coagulase positive?S. aureus?with percentage 43% (30/70) and coagulase negative?S. aureus?57% (40/70). CNS other than?S. aureus?was detected with percentage 65% (130/200) from subclinical mastitic cows. We examine sixty isolates of staphylococci recovered from subclinical mastitis in dairy cattle which divided as ten isolates of coagulase positive?S. aureus?(CP?S. aureus), ten isolates of coagulase negative?S. aureus(CN?S. aureus) and forty isolates of coagulase negative staphylococci (CNS) which identified using API-Staph Kits as?S. chromogenes,?S. simulans,?S. haemolyticus,?S. epidermidis?and?S. cohnii.?The genotypic detection of?coa?gene and?mecA gene was screened in CP?S. aureus, CN?S. aureus?and CNS.展开更多
The antibiotic batumin, produced by Pseudomonas batumici, has been shown to be highly active against 123 type and reference strains and clinical isolates of 30 Staphylococcus species (including MRSA and small colony v...The antibiotic batumin, produced by Pseudomonas batumici, has been shown to be highly active against 123 type and reference strains and clinical isolates of 30 Staphylococcus species (including MRSA and small colony variants—(SSCVs) of S. aureus, S. epidermidis and S. haemolyticus). Batumin activity against these bacteria did not depend on the species, origin or resistance to other antibiotics and its MIC was 0.0625 - 0.5 mg/ml. Batumin influence on biofilm formation was studied in clinical isolates of S. aureus, S. epidermidis and S. intermedius. Addition of batumin at a concentration of half of the MIC in the broth, i.e. 0.125 μg/ml, decreased the biofilm of 16 out of 20 S. aureus strains to varying degrees. Batumin was more effective against Staphylococcus strains with strong biofilm formation. Using atomic-force microscopy, it could be shown that batumin reduced the number of S. aureus ATCC 25923 adherent cells more than fourfold. The adherent cells of staphylococci were visualized as monolayers of separate islets. A detailed study of the surface of bacterial cells treated with batumin allowed to establish significant reduction of their roughness values. Observed values were typical for planktonic S. aureus cells. The obtained data explain one of the mechanisms of the antimicrobial activity of batumin, which is based оn preventing the formation of S. aureus biofilm. As such, batumin could be considered as an agent offering opportunities for the treatment of staphylococcal biofilm-associated infections.展开更多
Background:Currently,coagulase negative staphylococci(CoNS)have got much attention as a serious health problem especially in neonates and children.High incidence of antibiotic resistance,in particular methicillin resi...Background:Currently,coagulase negative staphylococci(CoNS)have got much attention as a serious health problem especially in neonates and children.High incidence of antibiotic resistance,in particular methicillin resistance,has complicated the treatment of these organisms.The aim of this study is to determine the susceptibility to different antimicrobial agents and the prevalence of macrolides-lincosamides-streptogramins B(MLS_(B))resistance in CoNS isolates obtained from pediatric patients.Methods:Totally 157 CoNS isolates from various clinical samples were examined for antibiotic resistance using disk diffusion and E-test methods.Double-disk test was applied to detect constitutive and inducible MLSB resistance(cMLS_(B)and iMLS_(B))phenotypes.Results:Resistance to methicillin was seen in 98(62.4%)isolates.All isolates were susceptible to vancomycin and linezolid.The prevalence of resistance to antibiotics tested was as follows:fusidic acid(n=58,36.9%),gentamicin(n=73,46.5%),ciprofloxacin(n=81,51.6%),clindamycin(n=112,71.3%),erythromycin(n=129,82.2%)and trimethoprim/sulfamethoxazole(n=133,84.7%).iMLS_(B)phenotype was seen in 14(8.9%)isolates,and 18(11.5%)and 98(62.4%)isolates showed MS and cMLS_(B)phenotypes,respectively.We observed that high overall antibiotic resistance rates were associated significantly with methicillin resistance.Conversely,iMLS_(B)phenotype was correlated neither with methicillin resistance nor with invasiveness.Conclusion:Given the similarity observed between the prevalence of iMLS_(B)and MS phenotypes,the performance of disk diffusion induction test is strongly recommended in our region.展开更多
Background: Coagulase negative Staphylococci (CoNS) positive blood cultures represent a complex and common challenge in clinical medicine. CoNS are common in skin flora and are often mistaken as contamination. Convers...Background: Coagulase negative Staphylococci (CoNS) positive blood cultures represent a complex and common challenge in clinical medicine. CoNS are common in skin flora and are often mistaken as contamination. Conversely, CoNS can also be implicated in severe and life-threatening bacteremia requiring prompt treatment. A gray area in terms of treatment approach exists for health care providers. The primary aim of this study was to examine predictive factors in patients who have positive CoNS blood cultures that met the CDC case definition of a laboratory confirmed bloodstream infection (LCBI-II) that were subsequently found to have clinically significant true bacteremia. Methods: A retrospective cohort of 288 patients that had at least two separate blood cultures positive for a coagulase negative Staphylococci between November 1st, 2017, and November 1st, 2018, were examined to determine if there were any patient specific factors that would indicate a true bacteremia with CoNS. Results: Retrospective regression analysis demonstrated that those subjected to antibiotics for two days or more (OR = 3.01), those subjected to antibiotics for seven days or more (OR = 2.86), and patients with central access (OR = 4.06) were more likely to have a true infection. Although not statistically significant, an association was also found in immunosuppressed patients (OR = 1.65), and in patients with implanted hardware (OR = 1.16). Conclusion: Patients receiving antibiotics for greater than two days and patients with a central line were more likely to have a true bloodstream infection with coagulase negative Staphylococci.展开更多
基金Supported by Faculty of Veterinary Medicine.University of Naples"Federico II".Naples Italy
文摘Objective:To investigate the prevalence of methicillin-resistant staphylococci(MRS)which is a potencial risk factor of transmission between animals and humans in different types of horses(harness racing-horses,breeding mares and riding-horses)and to compare the antimicrobial resistance of the isolates.Methods:A total of 191 healthy horses,housed at different locations of the Campania Region(Italy),were included in the study.Nasal swab samples were collected from each nostril of the horses.The mecA gene was detected by a nested PCR technique.Antibiotic susceptibility was tested for each isolate.Results:MRS was isolated from nasal samples of 68/191(35.6%;95%CI:28.9%-42.9%)healthy horses.All isolates were coagulase-negative with the exception of two coagulase-positive MRS strains,identified as Staphylococcus aureus and Staphylococcus pseudintermedius.2/83(2.4%;95%,CI:0.4%-9.2%).Interestingly,both coagulase-positive MRS isolates were from harness racing-horses.These horses also presented a significantly higher positivity for MRS(53.3%;95%CI:40.1%-66.1%)than the breeding mares and riding-horses groups.Antibiotic susceptibility testing showed difference between isolates due to different origins except for an almost common high resistance to aminopenicillins,such as ampicillin and amoxicillin.Conclusions:It can be concluded that harness racing-horses may act as a significant reservoir of MRS as compared to breeding mares and riding-horses.
文摘The coagulase-negative staphylococci (CoNS) group was considered saprophytic or rarely pathogenic for many years. Since the first case of septicemia caused by CoNS, there has been a progressive increase in the prevalence of healthcare-associated infections caused by CoNS. The CoNS group has emerged as one of the main causes of nosocomial infections related to vascular catheters and prostheses, especially among immunocompromised patients. This gradual increase in infections is due to the change in the relationship between patients and procedures since CoNS are closely related to devices implanted in the human body. CoNS are successful in colonizing the host because they have several virulence mechanisms, such as biofilm formation and production of enzymes and toxins, in addition to several mechanisms of resistance to antimicrobials. Despite their great clinical relevance, few studies have focused on CoNS’s pathogenicity and resistance to antimicrobials, which reveals the current need to better understand the factors by which this group became pathogenic to humans and other animals. This review aims to synthesize the aspects related to the pathogenicity and antimicrobial resistance in CoNS.
文摘Staphylococci strains, like the majority of bacterial strains, have developed the resistance to several antibiotics, including Quinolones and Fluoroquin-olones In the Republic of the Congo, cases of resistance leading to treat-ment failures have been observed during the treatment of staphylococcal infections with antibiotics in hospitals. The objective of this study was to identify the Quinolone/Fluoroquinolone resistance genes from staphylo-cocci strains isolated in hospitals. A total of 51 strains of Staphylococci were isolated, including 16 (31.37%) community strains, and 35 (68.62%) clinical strains. 46 strains of Staphylococcus aureus (S. aureus) and 5 SCNs were identified. A total of 34 DNA fragments from different strains resistant to Quinolones/Fluoroquinolones, including 21 (61.67%) DNA fragments from clinical S. aureus and 13 (38.23%) from community SCN strains were analyzed by the molecular method (genotypic detection) by PCR. The genotypic results made it possible to identify the gyrA, grLA and norA genes and to show that these genes are involved in the resistance of the strains to the various antibiotics used. The grLA gene was the most identified gene with a frequency of 75%. The gyrA and grLA genes have been identified in Staphylococcus aureus and Coagulase Negative Staphy-lococci. The norA gene, on the other hand, has only been identified in Staphylococcus aureus. Two mechanisms are essentially involved in the resistance of Staphylococci to quinolones/Fluoroquinolones, the mecha-nism of resistance by efflux, which takes place thanks to a transmembrane protein coded by the norA gene and by point mutations (substitution and deletion of acids or nucleotides) observed within the protein and nucleic sequences of the chromosomal gyrA and grLA genes.
文摘The pathogenic effect of Staphylococci is due to extra-cellular factors and properties such as adherence and biofilm production. The nature of the biofilm and the physiological properties of biofilm-producing bacteria result in an inherent antibiotic resistance and require further investigation. Two hundred and sixty Staphylococcal strains were cultured from 600 clinical specimens obtained from hospitalized patients. Among these, 155 were identified as coagulase-positive (CPS) and 105 as coagulase-negative (CNS) staphylococci. Staphylococcal strains were tested for biofilm production using the tissue culture plate (TCP) method. TCP detection showed that of the 155 CPS, 124 (80%) were biofilm producers, while 63 (60%) of the 105 CNS were biofilm producers. Biofilm-producing strains were scanned by scanning electron microscope (SEM) to confirm biofilm formation, study biofilm production, and examine antibiotic effects on biofilm formation. Disc diffusion method was used to study resistance of planktonic and biofilm-forming cells to antibiotics. Planktonic cells were less resistant to antibiotics than biofilm-forming cells. Microbroth dilution method and a new BioTimer assay were used to determine antibiotic MICs affecting planktonic and biofilm cells. Both methods showed that the MICs for planktonic cells were less than that for biofilm cells. The BioTimer assay was therefore found to be sensitive, accurate, and reliable, with results in agreement with those from the broth dilution method and SEM.
文摘Emerging antimicrobial resistance among CNS is a concern in veterinary and human medicine. Coagulase test is considered as the key test to differentiate staphylococci to two groups, coagulase positive staphylococci (CPS) and coagulase negative staphylococci (CNS). A total of 200?Staphylococci?strains were isolated with percentage 66.7% (200/300) from quarter milk samples. The total of?S. aureus?strains are 70 with percentage 35% (70/200). Among 70 strains of?S. aureus, 30 strains are coagulase positive?S. aureus?with percentage 43% (30/70) and coagulase negative?S. aureus?57% (40/70). CNS other than?S. aureus?was detected with percentage 65% (130/200) from subclinical mastitic cows. We examine sixty isolates of staphylococci recovered from subclinical mastitis in dairy cattle which divided as ten isolates of coagulase positive?S. aureus?(CP?S. aureus), ten isolates of coagulase negative?S. aureus(CN?S. aureus) and forty isolates of coagulase negative staphylococci (CNS) which identified using API-Staph Kits as?S. chromogenes,?S. simulans,?S. haemolyticus,?S. epidermidis?and?S. cohnii.?The genotypic detection of?coa?gene and?mecA gene was screened in CP?S. aureus, CN?S. aureus?and CNS.
文摘The antibiotic batumin, produced by Pseudomonas batumici, has been shown to be highly active against 123 type and reference strains and clinical isolates of 30 Staphylococcus species (including MRSA and small colony variants—(SSCVs) of S. aureus, S. epidermidis and S. haemolyticus). Batumin activity against these bacteria did not depend on the species, origin or resistance to other antibiotics and its MIC was 0.0625 - 0.5 mg/ml. Batumin influence on biofilm formation was studied in clinical isolates of S. aureus, S. epidermidis and S. intermedius. Addition of batumin at a concentration of half of the MIC in the broth, i.e. 0.125 μg/ml, decreased the biofilm of 16 out of 20 S. aureus strains to varying degrees. Batumin was more effective against Staphylococcus strains with strong biofilm formation. Using atomic-force microscopy, it could be shown that batumin reduced the number of S. aureus ATCC 25923 adherent cells more than fourfold. The adherent cells of staphylococci were visualized as monolayers of separate islets. A detailed study of the surface of bacterial cells treated with batumin allowed to establish significant reduction of their roughness values. Observed values were typical for planktonic S. aureus cells. The obtained data explain one of the mechanisms of the antimicrobial activity of batumin, which is based оn preventing the formation of S. aureus biofilm. As such, batumin could be considered as an agent offering opportunities for the treatment of staphylococcal biofilm-associated infections.
基金supported by Tabriz Research Center of Infectious and Tropical Diseases(grant 91/04)Tabriz University of Medical Sciences,Tabriz,Iran
文摘Background:Currently,coagulase negative staphylococci(CoNS)have got much attention as a serious health problem especially in neonates and children.High incidence of antibiotic resistance,in particular methicillin resistance,has complicated the treatment of these organisms.The aim of this study is to determine the susceptibility to different antimicrobial agents and the prevalence of macrolides-lincosamides-streptogramins B(MLS_(B))resistance in CoNS isolates obtained from pediatric patients.Methods:Totally 157 CoNS isolates from various clinical samples were examined for antibiotic resistance using disk diffusion and E-test methods.Double-disk test was applied to detect constitutive and inducible MLSB resistance(cMLS_(B)and iMLS_(B))phenotypes.Results:Resistance to methicillin was seen in 98(62.4%)isolates.All isolates were susceptible to vancomycin and linezolid.The prevalence of resistance to antibiotics tested was as follows:fusidic acid(n=58,36.9%),gentamicin(n=73,46.5%),ciprofloxacin(n=81,51.6%),clindamycin(n=112,71.3%),erythromycin(n=129,82.2%)and trimethoprim/sulfamethoxazole(n=133,84.7%).iMLS_(B)phenotype was seen in 14(8.9%)isolates,and 18(11.5%)and 98(62.4%)isolates showed MS and cMLS_(B)phenotypes,respectively.We observed that high overall antibiotic resistance rates were associated significantly with methicillin resistance.Conversely,iMLS_(B)phenotype was correlated neither with methicillin resistance nor with invasiveness.Conclusion:Given the similarity observed between the prevalence of iMLS_(B)and MS phenotypes,the performance of disk diffusion induction test is strongly recommended in our region.
文摘Background: Coagulase negative Staphylococci (CoNS) positive blood cultures represent a complex and common challenge in clinical medicine. CoNS are common in skin flora and are often mistaken as contamination. Conversely, CoNS can also be implicated in severe and life-threatening bacteremia requiring prompt treatment. A gray area in terms of treatment approach exists for health care providers. The primary aim of this study was to examine predictive factors in patients who have positive CoNS blood cultures that met the CDC case definition of a laboratory confirmed bloodstream infection (LCBI-II) that were subsequently found to have clinically significant true bacteremia. Methods: A retrospective cohort of 288 patients that had at least two separate blood cultures positive for a coagulase negative Staphylococci between November 1st, 2017, and November 1st, 2018, were examined to determine if there were any patient specific factors that would indicate a true bacteremia with CoNS. Results: Retrospective regression analysis demonstrated that those subjected to antibiotics for two days or more (OR = 3.01), those subjected to antibiotics for seven days or more (OR = 2.86), and patients with central access (OR = 4.06) were more likely to have a true infection. Although not statistically significant, an association was also found in immunosuppressed patients (OR = 1.65), and in patients with implanted hardware (OR = 1.16). Conclusion: Patients receiving antibiotics for greater than two days and patients with a central line were more likely to have a true bloodstream infection with coagulase negative Staphylococci.
