Showing papers on "Dalfopristin published in 2018"

Prevalence and Genetic Basis of Antimicrobial Resistance in Non-aureus Staphylococci Isolated from Canadian Dairy Herds.

Abstract: Emergence and spread of antimicrobial resistance is a major concern for the dairy industry worldwide. Objectives were to determine: (1) phenotypic and genotypic prevalence of drug-specific resistance for 25 species of non-aureus staphylococci, and (2) associations between presence of resistance determinants and antimicrobial resistance. Broth micro-dilution was used to determine resistance profiles for 1,702 isolates from 89 dairy herds. Additionally, 405 isolates were sequenced to screen for resistance determinants. Antimicrobial resistance was clearly species-dependent. Resistance to quinupristin/dalfopristin was common in Staphylococcus gallinarum (prevalence of 98%), whereas S. cohnii and S. arlettae were frequently resistant to erythromycin (prevalence of 63 and 100%, respectively). Prevalence of resistance was 10% against β-lactams and tetracyclines. In contrast, resistance to antimicrobials critically important for human medicine, namely vancomycin, fluoroquinolones, linezolid and daptomycin, was uncommon (< 1%). Genes encoding multidrug-resistance efflux pumps and resistance-associated residues in deducted amino acid sequences of the folP gene were the most frequent mechanisms of resistance, regardless of species. The estimated prevalence of the mecA gene was 17% for S. epidermidis. Several genes, including blaZ, mecA, fexA, erm, mphC, msrA, and tet were associated with drug-specific resistance, whereas other elements were not. There were specific residues in gyrB for all isolates of species intrinsically resistant to novobiocin. This study provided consensus protein sequences of key elements previously associated with resistance for 25 species of non-aureus staphylococci from dairy cattle. These results will be important for evaluating effects of interventions in antimicrobial use in Canadian dairy herds.

Antimicrobial susceptibility pattern of Staphylococcus aureus isolates from clinical specimens at Kenyatta National Hospital

Abstract: To determine antibiotic susceptibility pattern of S. aureus isolates from clinical specimens collected from patients at Kenyatta National Hospital from March 2014–February 2016, and to determine the prevalence and quarterly trends of MRSA throughout the study period. A total of 944 S. aureus isolates were analyzed. High sensitivity of S. aureus was observed for quinupristin/dalfopristin (100%), tigecycline (98.2), imipenem (98%), nitrofurantoin (97.6%), linezolid (97.3%), teicoplanin (97.1%) and vancomycin (95.1%). High resistance was recorded against penicillin G (91.9%), trimethoprim/sulfamethoxazole (56.9%) and tetracycline (33.2%). MRSA prevalence among the patients at KNH was 27.8%. Highest proportion (80%) of MRSA was in burns unit. Both MRSA and MSSA were highly susceptible to quinupristin/dalfopristin, tigecycline, linezolid, nitrofurantoin, ampicillin/sulbactam and vancomycin and showed high resistance to commonly used antibiotics such as gentamycin, erythromycin, levofloxacin and tetracycline. A majority of isolates were from pus specimen (68%).

Resistance mechanisms and clinical characteristics of linezolid-resistant Enterococcus faecium isolates: A single-centre study in South Korea

Abstract: Objectives This study aimed to determine the prevalence of linezolid-resistant (LR) vancomycin-resistant enterococci and to investigate the mechanisms of linezolid resistance with clinical and microbiological characterisation Methods All vancomycin-resistant Enterococcus faecium (VREF) isolated from blood and rectal swab cultures during 2012–2015 were tested for linezolid resistance LR-VREF isolates were tested for antimicrobial susceptibility, glycopeptide resistance genes and virulence genes Multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) were performed Isolates were tested for known mechanisms of linezolid resistance Results Among 389 VREF isolates, 7 (18%) were found to be resistant to linezolid All LR-VREF isolates carried the vanA gene Five isolates had both hyl and esp genes The isolates were susceptible to tigecycline, daptomycin and quinupristin/dalfopristin, except for one isolate with daptomycin resistance Two LR-VREF isolates recovered from patients with previous linezolid exposure contained the G2576T mutation in 23S rRNA and exhibited high-level resistance to linezolid (MIC > 64 mg/L) The other five isolates recovered from linezolid-naive patients revealed no known linezolid resistance mechanism and exhibited low-level resistance to linezolid (MICs = 8–16 mg/L) Plasmid-mediated genes encoding cfr or optrA were not detected LR-VREF isolates were represented by six different sequence types, belonging to hospital lineages, and were assigned to seven PFGE types Conclusions The prevalence of LR-VREF in this centre was low Both linezolid exposure and horizontal transmission appear to be responsible for acquisition of LR-VREF in hospitalised patients Prudent use of linezolid and improved infection control strategies are needed to limit the spread of LR-VREF

Daptomycin and vancomycin heteroresistance revealed among CC5-SCCmecII MRSA clone and in vitro evaluation of treatment alternatives.

Abstract: Objectives Methicillin-resistant Staphylococcus aureus (MRSA) is a threat to the success of clinical treatment. Besides high antimicrobial resistance rates, the presence of heterogeneous vancomycin-intermediate S. aureus (hVISA) and heterogeneous daptomycin-non-susceptible S. aureus (hDNSSA) in the hospital environment is underestimated and is associated with treatment failure. The aim of this study was to investigate MRSA dissemination in a Brazilian hospital and to evaluate the efficacy of various treatment options in vitro. Methods MRSA strains were typed by MLST, PFGE and SCCmec typing. Minimum inhibitory concentrations (MICs) to daptomycin, linezolid, quinupristin/dalfopristin, teicoplanin, tetracycline, tigecycline, vancomycin and tedizolid were determined by broth microdilution. The presence of a heterogeneous population was detected by population analysis profile (PAP). Regarding hVISA and hDNSSA strains, the sequences and expression levels of genes involved in resistance to daptomycin and vancomycin were determined as well as cell wall thickness and autolysis. Results ST5/ST105-SCCmecII lineage was prevalent amongst 27 clinical MRSA characterised in this study. Two hDNSSA strains (one also hVISA) were detected and were confirmed by PAP. Isolate SCMSC29 (hVISA and hDNSSA) showed increased expression of genes involved in cell wall metabolism, slight cell wall thickening, reduction of autolysis, and single nucleotide polymorphisms (SNPs) in the rpoB and mprF genes compared with the susceptible strain SCMSC31. SCMSC35 (hDNSSA) presented SNPs in the rpoB and mprF genes as well as a thickened cell wall. Conclusions Despite this worrying and hard to detect phenotype, treatment alternatives such as teicoplanin, linezolid, tetracycline, tigecycline, quinupristin/dalfopristin and tedizolid were all active against these isolates.

Molecular Epidemiology of Vancomycin-Resistant Enterococcus faecalis and Enterococcus faecium Isolated from Clinical Specimens in the Northwest of Iran.

Abstract: This study was conducted to investigate the phenotypic and genotypic characteristics of vancomycin-resistant Enterococcus faecalis and Enterococcus faecium. Antibiotic resistance and virulence genes in the aforementioned resistant isolates were studied using the epsilometer (E)-test and polymerase chain reaction (PCR). These isolates were subjected to typing by pulsed-field gel electrophoresis (PFGE). Thirty vancomycin-resistant enterococci (VRE; 18.75%) were isolated from a total of 160 various clinical specimens cultured for any bacterial growth. Of these, 11 (36.7%) isolates were identified as E. faecalis and 19 (63.3%) as E. faecium. Minimum inhibitory concentrations (MICs) of vancomycin, teicoplanin, and three alternative therapeutic options (linezolid, daptomycin, and quinupristin/dalfopristin) were determined using the E-test. Multiplex PCR was done for confirming species, identification of the resistant genotypes, and the detection of the virulence genes. Finally, the clonal relationship of all VRE strains was studied by PFGE. All VRE strains showed vancomycin MIC ≥256 μg/mL, and 27 (90%) isolates carried the vanA gene, whereas none of the isolates carried vanB. The most common resistance antibiotic pattern observed was toward rifampicin (n = 30 [100%]). Among all virulence genes studied, gelE (n = 28 [93.33%]) was found as the most prevalent virulent gene. VRE isolates exhibited 90%, 46.67%, 100%, and 66.67% resistance to teicoplanin, linezolid, quinupristin/dalfopristin, and daptomycin, respectively. Molecular typing demonstrated 16 PFGE types of VRE isolates (A-P). Although vanA was carried by most of the isolates, PFGE displayed small clonal dissemination among VR E. faecium and VR E. faecalis species.

Susceptibility of bacteria of the Enterococcus genus isolated on Lithuanian poultry farms

Abstract: The aim of this study was to test and analyse the antimicrobial susceptibility of Enterococcus isolates from Lithuanian poultry farms. Investigations were carried out during the years 2008-2009. The sampling sites, located all over the country, included eight poultry farms of large capacity. All samples were collected from broil- ers. Enterococcus spp. were isolated from intestines immediately after slaughtering. A total of 160 samples were collected, 20 samples from each farm. The MICs (Minimum Inhibitory Concentrations) of eleven antimicrobial agents were determined for each of the isolates using the broth microdilution method with specific microtitre plate panels (Trek Diagnostic Systems, Inc.). Susceptibility according to clinical breakpoints of chloramphenicol, linezolid, erythromycin, penicillin, quinupristin/dalfopristin, tetracycline, vancomycin, ciprofloxacin and nitrofurantoin was evaluated. One hundred and forty seven samples (92%) from a total of 160 tested samples were positive for Entero- coccus spp., however, only 74 strains were selected as non-duplicate isolates. The most predominant species were identified as E. faecium (38%), E. faecalis (17.5%), E. gallinarum (12%) and E. casseliflavus (12%). The most frequent resistance properties were resistances to tetracycline (75.6%), erythromycin (56.8%) and ciprofloxacin (41.9%). No strains resistant to vancomycin and linezolid were found. High percentages of susceptibility to chloramphenicol (82.4%) and penicillin (71.6%) were also observed. A high MIC of tigecycline (≥ 1 mg/l) to 12.2% of enterococci was determined during this study. 44.6% of tested strains had a high MIC (≥ 64 mg/l) to tylosin. There was no significant correlation found between resistances of different species to different antimicrobial agents in vitro.

Assessment of disinfectant and antibiotic susceptibility patterns and multi-locus variable number tandem repeat analysis of Staphylococcus epidermidis isolated from blood cultures

Abstract: Background and Objectives: Variable number tandem repeat (VNTR) patterns and resistance against three commonly used hospital disinfectants [0.5% (w/w) chlorhexidine digluconate (CHG) and 75% (w/w) alcohol (A), CHG-A; Quaternary ammonium compounds (QACs) and biguanides (B), QAC-B; and 70% (w/w) isopropanol (ISP) and 0.25% (w/w) QACs, ISP-QAC], as well as frequently used antibiotics, were evaluated among 115 Staphylococcus epidermidis blood isolates recovered from a children’s hospital in Tehran, Iran. Materials and Methods: Multi-locus variable number tandem repeat analysis (MLVA) was performed using primers targeting 5 VNTR loci on the genome of S. epidermidis isolates. Micro-broth dilution method and detection of qacA/B and smr genes were carried out for evaluating resistance against the disinfectants. Results: Out of the 115 isolates, 115 (100%) and 113 (98.3%) were susceptible to linezolid and quinupristin/dalfopristin, respectively. A total of 55.7% of the isolates were found to be multidrug resistant (MDR). All isolates had MICs of CHG-A and ISP-QAC of 8 folds lower and MIC of QAC-B 6 folds lower than that suggested by the manufacturers. The genes qacA/B and smr were found in 28 (24.3%) and 14 (12.2%) isolates, respectively. MLVA typing of the S. epidermidis isolates resulted in 106 VNTR patterns and 102 MLVA types for the 112 S. epidermidis isolates, considering that 3 were not typeable. Conclusion: MLVA typing of S. epidermidis isolates show a great diversity and that the isolates are still susceptible to the concentrations of disinfectants recommended for use by the manufacturers. In addition, the relatively high percentage of the MDR S. epidermidis isolates could cause MDR infections and act as reservoirs to transfer resistance determinants to S. aureus population. Therefore, it is important that suitable infection control strategies are employed to avoid the distribution of MDR isolates between personnel and patients in this medical centre.

Bacterial and fungal uropathogens in diabetic patients and their susceptibility patterns: case study of two hospitals in douala

Abstract: Background: Diabetic patients are more prone to develop urinary tract infections (UTI), than non-diabetic patients. These infections are responsible for considerable morbidity, particularly if they are unrecognised or untreated. The successful management of UTI in diabetic patients depends on the proper identification of the pathogens responsible and the selection of efficient antibiotics/antifungals against them. Methods: A cross-sectional study was carried out in the Endocrinology/Diabetic units of the General Hospital and the Laquintinie Hospital in Douala (Cameroon). Midstream urine samples were collected from the patients and analysed macroscopically and microscopically. Samples containing up to five leukocytes/mm3 were inoculated onto culture media for bacterial isolation and microbial load. Bacteriuria counts ≥10/mL was considered significant. Biochemical identification and susceptibility testing to antibiotics were carried out in positive cultures, using the VitekTM 2automated system. The susceptibility testing to antifungals was done by the disc diffusion method. Urine dipstick analysis was done using CombiScreenTM 11SYS PLUS. Results: Three hundred and fifteen patients comprising of 192 (60.95%) females, were enrolled. The overall UTI frequency was 20%, with rates of symptomatic bacteriuria and asymptomatic bacteriuria being 6.37% and 13.63% respectively. A total of 75 uropathogens were isolated, 3fungi (4%) and 72 bacteria (96%) strains. The most isolated bacteria were Escherichia coli (45.33%). Gram-positive cocci included Staphylococcus aureus, and coagulase negative Staphylococci were also found. The only fungus isolated was Candida albicans. The susceptibility rate for Gram-negative bacilli was 100% for Imipenem, 93.30% for Amikacin, and Piperacillin+Tazobactam. The lowest rates were observed for Amoxicillin and Cotrimoxazole. Gram-positive cocci were 100% susceptible to Moxifloxacin, Nitrofurantoin, Quinupristin/ Dalfopristin, Linezolid, Tetracycline, Tigecycline, and Rifampicin. The susceptibility rate for Vancomycin and Oxacillin were 66.70% and 55.50% respectively. All the isolated strains of C. albicans were susceptible to Econazole, Ketoconazole, Fluconazole and Flucytosine; and all were resistant to Nystatine. Conclusion: Many uropathogens were isolated from diabetic patients, and low susceptibilities to "first-line" drugs were observed. Dipstick urinalysis has a great contribution in urine culture examination.

Topical anti-infective formulation

Abstract: Disclosed herein are veterinary topical formulations comprising a halogenated salicylanilide, and an antibiotic selected from the group consisting of: fusidic acid, mupirocin, a pleuromutilin antibiotic, florfenicol, clindamycin, gentamicin, teicoplanin, vancomycin, tigecycline, fosfomycin, daptomycin, rifampicin, linezolid, quinupristin, dalfopristin, pristinamycin, cloxacillin, dicloxacillin, flucloxacillin, oxacillin and nafcillin. The veterinary topical formulations of the invention are useful in treating a bacterial infection a non-human animal.

Antibiogram patterns of staphylococcal speciesisolated from healthy individuals in nilai, negerisembilan, malaysia

Abstract: Antibiotic resistance is an alarming phenomenon worldwide, challenging the effectiveness of antibiotics which are used to treat infectious diseases. In this study, pure cultures of forty skin and nasal samples from healthy individuals in Nilai, Negeri Sembilan, were screened. Samples were inoculated on the nutrient agar plates to obtain single colonies, followed by sub-culturing and series of confirmatory tests such as Gram staining, catalase test, Mannitol Salt Agar, as well as cefoxitin disk-diffusion test to obtain pure MRSA and MRSE isolates. A total of 13 MRSA strains and one MRSE strain were obtained and subjected to antibiotic susceptibility testing on Mueller Hinton agar using Kirby-Bauer disk diffusion technique. All cefoxitin-resistant isolateswere resistant to penicillin G, erythromycin, linezolid, and vancomycin; 78% of them were resistant to teicoplanin, clindamycin, quinupristin/dalfopristin; 56% showed resistance to nalidixic acid and cefazolin while 33% of them showed resistance to cefuroxime. All isolates (100%) were susceptible to doxycycline, chloramphenicol, and ciprofloxacin. Eight different antibiogram patterns were obtained from these 14 isolates with resistance towards 11 out of 16 types of antibiotics used in this study. This finding which is a surveillance control method of antibiotic-resistant crisis is important as the results could provide an indication of the resistance patterns circulating among healthy individuals, and could contribute towards a more definitive antibiotic therapy of staphylococcal species infections in Malaysia