Showing papers on "Dalfopristin published in 2010"

Human infection associated with methicillin-resistant Staphylococcus pseudintermedius ST71

Abstract: Sir, Staphylococcus pseudintermedius is one of the most common pathogens isolated from skin and post-operative infections in dogs and cats and can also occasionally cause infections in humans. People working or living with animals are more likely to be colonized with S. pseudintermedius in their nasal cavities and human infection acquired from dogs has been recently reported. In recent years, there have been increasing numbers of infections in dogs and cats caused by methicillin-resistant S. pseudintermedius (MRSP) and a predominant MRSP clone is disseminating in dogs and cats throughout Europe. This MRSP clone belongs to the multilocus sequence type (MLST) ST71, spa type t02 and SmaI PFGE group J (ST71-t02-J) and contains the staphylococcal cassette chromosome element SCCmec II–III. It displays resistance to many classes of antibiotics and represents a challenge for therapy. Here, we report, to our knowledge, the first case of a human infection caused by MRSP ST71 emphasizing its zoonotic potential and therapeutic challenge. An adult patient presented to the doctor in 2009 with headache, watery eyes and a small oedema over the right eye. The patient had a history of recurrent rhinosinusitis and three surgical interventions had been performed over the previous 6 years, the last one in 2005. CT illustrated an obliteration of the right sinus frontalis with an expansive mucocele. Yet another surgical intervention was absolutely essential and post-operative treatment for 3 weeks with 500 mg of ciprofloxacin twice per day and 300 mg of clindamycin three times per day was given. Five weeks post-operatively, a purulent infection appeared. After 10 days of treatment with 875 mg of amoxicillin/125 mg of clavulanic acid twice daily and 300 mg of clindamycin three times daily and no improvement, a sample was sent for bacteriological analysis. The laboratory identified a multidrug-resistant Staphylococcus belonging to the Staphylococcus intermedius group (SIG) using the ID 32 STAPH system (bioMerieux, Marcy l’Etoile, France) and disc diffusion susceptibility testing (Oxoid Ltd, Basingstoke, UK). Based on these results, a local treatment with fusidic acid gauze and application of 2% mupirocin ointment four times a day for 8 days followed by a topical glucocorticoid/antibiotic combination therapy (0.5 mg/g fluocinonide, 2.5 mg/g neomycin, 0.25 mg/g gramicidin and 100000 IU/g nystatin) packing for 4 days improved the local condition. Six weeks after the purulent infection, the wound had healed with scarring and no bacterium was detectable in a repeat smear. Local follow-up treatment with steroids and routine check-ups confirmed the absence of residual infection. The multidrug-resistant Staphylococcus isolate was further identified as MRSP ST71-t02-J containing SCCmec II–III using MLST typing, spa typing, PFGE and SCCmec typing methods described previously. MICs of antibiotics were determined in Mueller–Hinton broth using custom Sensititre susceptibility NLV73 plates (Trek Diagnostics System, East Grinstead, UK) except for rifampicin, trimethoprim, kanamycin and fusidic acid, which were tested using home-made microbroth dilution plates. Antibiotic resistance genes were detected using a microarray. Mutations in topoisomerase genes gyrA and grlA were identified by sequencing of PCR products (Table 1). The isolate was susceptible to the antibiotics amikacin, chloramphenicol, fusidic acid, linezolid, nitrofurantoin, the combination quinupristin/dalfopristin, rifampicin and vancomycin (Table 1). The patient owned a male dog that needed home care because of various clinical problems such as diabetes, recurrent warts and abdominal tumour. The dog had consultations in various clinics and underwent several antibiotic treatments (details of substances could not be ascertained). The dog was euthanized before samples could be taken to determine whether it was a carrier of the strain. The patient also owned horses and cats; all of them were in good health without clinical signs. Even if the ultimate source of the MRSP infection could not be identified, the patient was infected with the same MRSP clone (ST71-t02-J with SCCmec II–III) that has been disseminating in dogs over Europe in recent years. A case similar to the one reported here has been described in the USA, where a woman developed sinusitis caused by a methicillinresistant SIG whose origin could be attributed to her pet dog. In that case, vancomycin and linezolid were used for treatment. The increasing number of dogs carrying MRSP constitutes a risk for pet owners to become colonized with MRSP, and MRSP infections in humans may also increase in the near future. It is therefore important to recognize MRSP as a zoonotic pathogen and have antibiotics available for the treatment of MRSP infections in humans. Therefore, antibiotics such as mupirocin, linezolid, quinupristin/dalfopristin, rifampicin and vancomycin that are used for decolonization or as ‘last resort antibiotics’ against methicillin-resistant staphylococci in humans should not be used for treatment in animals.

Assessment of linezolid resistance mechanisms among Staphylococcus epidermidis causing bacteraemia in Rome, Italy

Abstract: Objectives: To characterize linezolid resistance among blood cultured Staphylococcus epidermidis from patients at the Polyclinic Agostino Gemelli (2006-08). Isolates also showed elevated MICs of macrolide, lincosomide and streptogramin (MLS) compounds, which were investigated. Methods: Ten S. epidermidis exhibiting linezolid MICs≥4 mg/L were included. Isolates were screened for cfr mutations in 23S rRNA, L3, L4 and L22, and MLS genes by PCR/sequencing. Ribosomal proteins were compared with those from a linezolid-susceptible (MIC, 1 mg/L) clinical strain and ATCC 12228. cfr location was determined by Southern blot/hybridization. The cfr strain was submitted to plasmid curing. Epidemiology was assessed by PFGE and multilocus sequence typing (MLST). Results: S. epidermidis displayed linezolid MICs of 4 or 8 mg/L, except for strain 4303A (MIC, 64 mg/L). These organisms and a linezolid-susceptible strain exhibited L3 Leu101Val compared with ATCC 12228. Isolates also showed L3 Phe147Leu and A1a157Arg, and L4 Asn158Ser. Strain 12375A possessed L4 Lys68Arg. Isolates were wild-type for 23S rRNA and L22. cfr was plasmid located in strain 4303A and the plasmid-cured strain exhibited a linezolid MIC (4 mg/L) similar to that for cfr-negative strains (4-8 mg/L). All organisms harboured erm(A) and msr(A), while vga(A) was detected in several isolates. All isolates were clonally related and ST-23. Conclusions: L3 Phe147Leu and/or Ala157Arg appeared responsible for the elevated linezolid MIC, since adjacent alterations have been associated with resistance. L4 Asn158Ser has been reported in a linezolid-susceptible isolate and Lys68Arg detected here did not seem to provide an additive effect. Acquisition of cfr markedly increased (8- to 16-fold) the linezolid MICs. vga(A) was associated with higher MICs of quinupristin/dalfopristin and retapamulin.

Antimicrobial-Resistant Enterococci in Animals and Meat: A Human Health Hazard?

Abstract: Enterococcus faecium and Enterococcus faecalis belong to the gastrointestinal flora of humans and animals. Although normally regarded harmless commensals, enterococci may cause a range of different infections in humans, including urinary tract infections, sepsis, and endocarditis. The use of avoparcin, gentamicin, and virginiamycin for growth promotion and therapy in food animals has lead to the emergence of vancomycin- and gentamicin-resistant enterococci and quinupristin/dalfopristin-resistant E. faecium in animals and meat. This implies a potential risk for transfer of resistance genes or resistant bacteria from food animals to humans. The genes encoding resistance to vancomycin, gentamicin, and quinupristin/dalfopristin have been found in E. faecium of human and animal origin; meanwhile, certain clones of E. faecium are found more frequently in samples from human patients, while other clones predominate in certain animal species. This may suggest that antimicrobial-resistant E. faecium from a...

Predictors of persistent methicillin-resistant Staphylococcus aureus bacteraemia in patients treated with vancomycin

Abstract: Received 14 January 2010; returned 22 January 2010; revised 28 January 2010; accepted 30 January 2010 Objectives: The high prevalence of methicillin-resistant Staphylococcus aureus (MRSA) coupled with an increase in vancomycin use have induced vancomycin tolerance in MRSA, adversely affecting the outcome of MRSA bacteraemia. This study aimed to identify predictors of persistent MRSA bacteraemia (PMRSAB) in patients treated with vancomycin. Methods: A retrospective, case-control study was performed at a university hospital in Korea from January 2006 to February 2009. Subjects included 96 patients who had MRSA bacteraemia and received vancomycin under therapeutic drug monitoring. We compared the clinical characteristics, management and outcomes of cases with PMRSAB (� 7d ays,n¼31) with controls with non-PMRSAB (� 3 days, n¼32). Vancomycin MICs were determined by the Vitek 2 system. Results: Of 96 patients with MRSA bacteraemia, MRSA isolates from 21 patients (21.9%) showed a vancomycin MIC of 2 mg/L. Independent predictors of PMRSAB were: retention of implicated medical devices [odds ratio (OR), 10.35; 95% confidence interval (CI), 1.03‐104.55]; MRSA infection of at least two sites (OR, 10.24; 95% CI, 1.72‐61.01); and vancomycin MIC of 2 mg/L (OR, 6.34; 95% CI, 1.21‐33.09). The frequency of side effects and mean trough serum vancomycin concentrations were not significantly different between the two groups. Sixteen patients with PMRSAB subsequently received teicoplanin+arbekacin, linezolid or quinupristin/ dalfopristin, due to vancomycin failure or intolerance. Conclusions: To minimize the risk of PMRSAB, early removal of implicated devices and evaluation for metastatic infections should be encouraged. Alternative antibiotic therapy is warranted for infections due to isolates with elevated vancomycin MICs, as well as for the high rates of side effects.

DNA methylase modifications and other linezolid resistance mutations in coagulase-negative staphylococci in Italy

Abstract: Background: Despite 10 years of clinical use, linezolid resistance in Staphylococcus aureus and coagulase-negative staphylococci (CoNS) is still a rare phenomenon. This study reports the mechanisms of resistance and strain types seen in clusters of linezolid-resistant CoNS from two different hospitals in Italy during the period 2008-09. Methods: Genes associated with linezolid resistance were subjected to molecular analysis and isolates were characterized by PFGE macrorestriction analysis using SmaI. Results: Thirty-three linezolid-resistant isolates of methicillin-resistant CoNS comprising Staphylococcus epidermidis (24), Staphylococcus hominis (5) and Staphylococcus simulans (4) were studied. The isolates showed varying levels of linezolid resistance. Almost all isolates for which linezolid MICs were 64 mg/L possessed point mutations in domain V of 23S rRNA, while isolates for which the MICs were 256 mg/L expressed methylase activity at position A2503 mediated by the cfr gene. Overall, the isolates showed reduced susceptibility to vancomycin (MICs 1-2 mg/L) and 11 of the 33 isolates showed no susceptibility to teicoplanin. These strains were also resistant to chloramphenicol (28 of 33), lincomycin (24 of 33), erythromycin (17 of 33) and quinupristin/dalfopristin (13 of 33). S. epidermidis isolates, showing mutations or methylase modifcations, belonged to different PFGE profiles and to two different sequence types (ST2 and ST23), in which the cfr gene was carried on a plasmid of ∼50 kb. Conclusions: Clinical CoNS strains with resistance to linezolid and other second-line antibiotics, as well as reduced susceptibility to glycopeptides, have emerged in Italy.

Prevalence and persistence of antimicrobial resistance in broiler indicator bacteria

Abstract: This study explored the prevalence and persistence of acquired antimicrobial resistance in Escherichia coli and Enterococcus faecium from healthy broilers. In 32 broiler farms, cloacal samples were taken during two production rounds, with one production round in between. For 10 of the sampled flocks, samples from the carcasses at the slaughterhouse were also collected. For E. coli, high levels of resistance were found for ampicillin, nalidixic acid, streptomycin, tetracycline, and the combination of trimethoprim and sulfonamide. Over 58% of all the isolates showed resistance to four or more antimicrobial agents. Only 4.8% were fully susceptible for all 14 drugs tested. A remarkably high resistance rate (up to 41%) to ceftiofur was found. The enterococci were frequently resistant to macrolides, tetracycline, and the combination quinopristin/dalfopristin. Over 80% displayed acquired resistance to four or more antimicrobial agents, and 3.9% were fully susceptible for the eight agents tested. Resistance was f...

Telavancin activity against Gram-positive bacteria isolated from respiratory tract specimens of patients with nosocomial pneumonia

Abstract: Objectives The antimicrobial activity of telavancin against 2279 clinical Gram-positive cocci obtained from patients with nosocomial pneumonia [NP; including those with ventilator-acquired pneumonia (VAP)] located in numerous medical centres worldwide was evaluated. Methods A contemporary collection of 2279 non-duplicate consecutive Gram-positive clinical isolates were submitted from 87 hospitals located in North America (913 isolates), Latin America (222 isolates), Europe (690 isolates), and the Asia-Pacific region (454 isolates) as part of the international telavancin surveillance programme for 2007-08. Isolates were tested for susceptibility by the reference broth microdilution method (with 2%-5% lysed horse blood added for testing of streptococci). Interpretive criteria were those from CLSI (M100-S20, 2010) except for telavancin, for which the susceptible breakpoints approved by the US FDA were applied. Results Telavancin was highly active against Staphylococcus aureus (MIC(90), 0.25 mg/L; 100% susceptible), coagulase-negative staphylococci (MIC(90), 0.25 mg/L), Streptococcus pneumoniae (MIC(90), 0.03 mg/L), viridans group streptococci (MIC(90), 0.06 mg/L; 100% susceptible), β-haemolytic streptococci (MIC(90), 0.06 mg/L; 100% susceptible) and vancomycin-susceptible enterococci (MIC(90), 0.5 mg/L; 100% susceptible). Telavancin inhibited all staphylococci at ≤ 0.5 mg/L. Among enterococci non-susceptible to vancomycin (all Enterococcus faecium), telavancin was active against isolates exhibiting a VanB phenotype (MIC, 0.06-0.12 mg/L), but less potent against VanA strains (MIC, ≥ 2 mg/L). Conclusions Telavancin demonstrated equal or greater potency than the comparators (vancomycin, teicoplanin, daptomycin, linezolid and quinupristin/dalfopristin) against Gram-positive pathogens implicated in NP. Telavancin showed elevated MIC values only against enterococcus isolates showing a VanA phenotype. The continued appearance of multidrug-resistant pathogens among Gram-positive isolates, mainly S. aureus, necessitates the introduction of new agents and longitudinal surveillance to monitor for the potential emergence of resistance.

Quinupristin-dalfopristin versus linezolid for the treatment of vancomycin-resistant Enterococcus faecium bacteraemia: efficacy and development of resistance.

Abstract: Quinupristin-dalfopristin and linezolid are widely used for the treatment of vancomycin-resistant Enterococcus faecium (VREF) infections. Increasing resistance of VREF to quinupristin-dalfopristin and linezolid is a cause for concern. To determine the efficacy of and the rate of development of resistance to quinupristin-dalfopristin and linezolid, we analyzed all episodes of clinically significant VREF bacteraemia at a tertiary-care hospital from January 2003 to June 2007. The main outcomes were rates of 30-day mortality, microbiological response, and development of resistance. Fifty-two patients were treated with quinupristin-dalfopristin and 61 were treated with linezolid. Baseline demographic and clinical characteristics were similar between the 2 groups. There were no significant between-group differences in 30-day mortality (48% in the quinupristin-dalfopristin group vs 41% in the linezolid group; p = 0.45) or microbiological response (60% vs 66%; p = 0.51). However, prolonged bacteraemia (18% of 45 evaluable cases vs 4% of 55 evaluable cases; p = 0.04) and development of resistance in blood isolates (11% vs 0%; p = 0.02) were more frequently observed in the quinupristin-dalfopristin group than in the linezolid group. There was no significant difference between the efficacy of quinupristin-dalfopristin and linezolid. However, prolonged bacteraemia and the development of resistance were more common in quinupristin-dalfopristin-treated patients.

Activity of quinupristin/dalfopristin against extracellular and intracellular Staphylococcus aureus with various resistance phenotypes

Abstract: Objectives Treatment of chronic or recurrent Staphylococcus aureus infections may require using antibiotics with activity against intracellular multiresistant organisms. Quinupristin/dalfopristin (3:7) has been examined in this context. Methods Quinupristin and dalfopristin were used separately or mixed. Strains used were: (i) methicillin-susceptible and -resistant S. aureus (MSSA and MRSA); (ii) one vat(B) MSSA and msr(A/B) MRSA; (iii) erm(A)(+) [MSSA, MRSA, vancomycin-intermediate S. aureus (VISA) and vancomycin-resistant S. aureus (VRSA)]; and (iv) one erm(A/B)(+) cfr(+) MRSA resistant to quinupristin, dalfopristin and their combination. Assessment of activity was determined by: (i) MICs (CLSI method); and (ii) concentration-response curves in broth and after phagocytosis by THP-1 macrophages, with descriptors of the model (E(min)) and the pharmacodynamic response [maximal relative efficacy (E(max)), relative potency (EC(50)) and apparent static concentration (C(static))]. Results erm(A)-positive strains were all susceptible to quinupristin/dalfopristin (except strain CM05), with MICs not adversely influenced by acid pH or by the MRSA, VISA or VRSA character of the strain. In concentration-response experiments, quinupristin/dalfopristin showed similar patterns for all strains (except strain CM05), with a >3 log(10) cfu decrease in broth and a 1.3 [erm(A) strain] to 2.6 [fully susceptible, vat(B) and msr(A/B) strains] log(10) cfu decrease for intracellular bacteria at the maximal extracellular concentration tested (25 mg/L). Maximal extracellular and intracellular activity was obtained for a quinupristin/dalfopristin ratio of 3:7. For strain CM05, quinupristin/dalfopristin was static in all conditions. Conclusions Based on historical comparisons with rifampicin, fluoroquinolones, lipoglycopeptides and other antistaphylococcal drugs with a large accumulation in eukaryotic cells, quinupristin/dalfopristin appears to be one of the most active antibiotics against intracellular S. aureus studied in this model so far, largely irrespective of its resistance phenotype.

Neonatal community-acquired pneumonia: pathogens and treatment.

Abstract: Aim: To analyse the bacterial pathogens and drug sensitivities for neonatal community-acquired pneumonia. Methods: Seven hundred sixty sputum samples from newborns with community-acquired pneumonia were cultured to determine microbial organisms present and their drug sensitivities. Results: Of the 760 specimens, 425 grew pathogens for a 55.9% positive rate. Among the 425 positive cultures, 278 grew gram-negative organisms (65.4%), 142 grew gram-positive organisms (33.3%), while 5 grew fungus (1.3%). The most common gram-negative organisms were Escherichia coli, Klebsiella pneumoniae and Hemophilus influenzae, while the most common gram-positive organisms were Staphylococcus aureus, Staphylococcus epidermidis and Staphylococcus haemolyticus. To the gram-negative organisms, the most sensitive drugs were meropenem, imipenem and amikacin, while to the gram-positive ones were vancomycin, teicoplanin and quinupristin/dalfopristin. Conclusions: The most common causative bacteria were gram-negative organisms, which were highly sensitive to Meropenem, Imipenem and Amikacin, yet often treatable with more focused antibiotic coverage, which depended on the bacterium identified.

[Antimicrobial susceptibility of clinical isolates of aerobic Gram-positive cocci and anaerobic bacteria in 2006].

Abstract: The activity of antibacterial agents against aerobic Gram-positive cocci (26 species, 1022 strains) and anaerobic bacteria (23 species, 184 strains) isolated from clinical specimens in 2006 at 16 clinical facilities in Japan were studied using either broth microdilution or agar dilution method. The ratio of methicillin-resistant strains among Staphylococcus aureus and Staphylococcus epidermidis was 53.0% and 65.8%, suggesting that resistant strains were isolated at high frequency. Vancomycin (VCM) and quinupristin/dalfopristin (QPR/DPR) had good antibacterial activity against methicillin-resistant S. aureus and methicillin-resistant S. epidermidis, with MIC90s of < or = 2 micrcog/mL. The ratio of penicillin (PC) intermediate and resistant strains classified by mutations of PC-binding proteins among Streptococcus pneumoniae was 87.6%. Ceftriaxone, cefpirome, cefepime, carbapenem antibiotics, VCM, teicoplanin, linezolid(LZD) and QPR/DPR had MIC90s of < or = 1 microg/mL against PC-intermediate and resistant S. pneumoniae strains. Against all strains of Enterococcus faecalis and Enterococcus faecium, the MICs of VCM and TEIC were under 2 microg/mL, and no resistant strain was detected, suggesting that these agents had excellent activities against these species. 10.9% of E. faecalis strains or 3.5% of E. faecium strains showed intermediate or resistant to LZD. 24.4% of E. faecium strains showed intermediate or resistant to QPR/DPR. Against all strains of Clostridium difficile, the MIC of VCM were under 1 microg/mL, suggesting that VCM had excellent activity against C. difficile. Carbapenems showed good activity against Peptococcaceae, Bacteroides spp., and Prevotella spp. However since several strains of Bacteroides fragilis showed resistant to carbapenems and the susceptibility of this species should be well-focused in the future.

Antibiotic susceptibility profile of methicillin-resistant staphylococci isolated from nasal samples of hospitalized patients

Abstract: The aim of this study was to evaluate the prevalence rate and antibiotic resistant pattern of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE). A prospective study was conducted at Holy Family Hospital Rawalpindi, Pakistan and Microbiology Research Laboratory, Quaid-i-Azam University, Islamabad, Pakistan during the period from December 2007 to August 2008. The antibiotic resistance pattern was studied for MRSA and MRSE isolated from nasal samples from patients admitted in medical and surgical intensive care units. The study was conducted on 283 isolates. The results depicted that 25% isolates of S. aureus were MRSA and 29.78% isolates of S. epidermidiswere MRSE. All MRSA and MRSE were susceptible to vancomycin and quinopristin/dalfopristin while all isolates of MRSE were susceptible to teicoplanin. All the isolates of MRSA and MRSE were multidrug-resistant. The susceptibility of the isolates to the drugs varied greatly. The resistance rate of MRSA to various antibiotics was found to be as follow: cephalaxin (90%), cephalothin (58%), cephradine (86%), ciprofloxacin (80%), gentamicin (34%), imipenum (42%), levofloxacin (75%), tetracycline (49%), rifampicin (14%) and teicoplanin (3%). The resistance rate of MRSE to various antibiotics was found to be as follow: cephalaxin (64%), cephalothin (29%), cephradine (64%), ciprofloxacin (50%), gentamicin (21%), imipenum (7%), levofloxacin (21%), tetracycline (21%) and rifampicin (29%). The minimum inhibitory concentration (MIC) value for MRSA and MRSE in case of vancomycin ranged 1-4 μg/ml, for tetracycline 4-128 μg/ml, for rifampicin 0.5-32μg/ml and for gentamicin 0.5 – 64 μg/ml. Both MRSA and MRSE showed variable susceptibility with different antibiotic groups but high susceptibility with streptogramin and glycopeptide antibiotics. Key words: Antibiotic resistance, staphylococcus aureus, staphylococcus epidermidis, minimum inhibitory concentration.

Surveillance of antimicobial resistance ratio of E. coli and Enterococcus spp. isolated from fecal and carcasses of pigs in slaughterhouse

Abstract: The present study was conducted to investigate isolation and antimicrobial resistance ratio of E. coli, E. faecium and E. faecalis from feces(l50 samples) and carcasses (150 samples) on slaughtered pigs from 6 slaughterhouse of 13 cities in the Gyeongnam during the period from January 2009 to December 2009. Isolation ratio of E. coli from feces and carcasses were 98 (65.3%) and 110(73.3%), respectively, and simultaneously, E. faecalis and E. faecium from feces and carcasses were isolated 21 (14%), 52(34.7%) and 18(12%), 14 (9.3%), respectively. All E. coli isolated from feces and carcasses except cefepime (0%) and ceftiofur (0%) were exhibited 2.4~83.6% of resistance to teteracycline (83.6%), ampicillin (68.2%), streptomycin (60%), chloram-phenicol (53.8%) and cephalothin (2.4%). All E. faecalis isolated from feces and carcasses except penicillin(0%) and vancomycin (0%) were exhibited 2.7~80.8% of resistance to teteracycline (80.8%), quinupristin/dalfopristin (78%), erythromycin (56.1%), streptomycin (43.8%) and bacitracin (2.7%). All E. faecium isolated from feces and carcasses except gentamicin (0%), vancomycin (0%), florfenicol (0%), linezloid (0%) and bacitracin (0%) were exhibited 3.1~53.1% of resistance to rifampin (53.1%), erythromycin and tetracycline (25%), penicillin (15.6%), ciprofloxacin (9.3%), and streptomycin, chloramphenicol, and quinupristin/dalfopristin (3.1%). According to the heard size, resistance ratio of E. coli strains isolated from feces and carcasses in slaughtered pigs-breeding farms over 1,500 heard to tetracycline, ampicillin, streptomycin and chloramphenicol showed higher resistance ratio (1.0~16.8%) than those of farms-breeding under 1,500 heard. From the our results, we suggest that a few of antimicrobials were used in the Gyeongnam than the other cities.

Characterization of Vancomycin-Resistant Enterococci Isolated from Stools and Their Acquisition of Vancomycin Resistance

Abstract: We have isolated 6 vancomycin resistant (VR) Enterococcus faecium and 5 VR-E. gallinarum. Vancomycin resistant enterococcus (VRE) isolates were resistant to multi-drugs, but susceptible to linezolid and quinupristin/dalfopristin. VRE isolates showed 10 VanA phenotypes and 1 VanB phenotype (E. gallinarum). However, all of them showed vanA genotype. vanA gene was detected on both genomic and plasmid DNA from all VRE isolates. Almost of VR-E. faecium had IS1216V which is worldwide type and almost of VR-E. gallinarum had IS1542 which is European type. IS1216V and IS1542 genes were not related with antibiotic types of VRE. Copy numbers of vanA were decreased in VRE with IS1216V or IS1542 but not in VRE with both ISs in broth without vancomycin. The copy numbers of vanA were significantly decreased in VanB phenotype of VRE with IS1542 in broth without vancomycin. Copy numbers of vanA were recovered in the presence of vancomycin. Growth time of reference E. faecium is faster than that of reference E. faecalis when cultured in the broth containing vancomycin. Reference strains cultured in the broth containing vancomycin showed intermediate resistance or resistance to antibiotics without acquisition of van genes. Naturally, multidrugresistant E. faecium might be fast adapted in the presence of vancomycin compared to E. faecalis. Taken together, VanA phenotype E. gallinarum as well as E. feacium have been increasing in nosocomial infection and showed acquired inducible resistance. E. faecium and E. faecalis showed intermediate resistance in long exposure of vancomycin without acquisition of vanA.

Detection of antimicrobial sensitiveness of isolates of Listeria monocytogenes from food chain using Vitek 2 Compact Biomerieux

Abstract: Sensitivity of 26 Listeria monocytogenes isolates toward 18 antimicrobial substances used in veterinary and human medicine was examined using the automated VITEK 2 Compact system bioMerieux The obtained results indicate that L monocytogenes strains isolated from food and food processing environment had resistance to several or more antimicrobial substances that are commonly used in the treatment in animals and humans Results showed resistance of all 26 (100%) isolates toward Benzylpenicilin, Ampicilin/Sublactam, Oxacillin, Imipenem and Fosfomycine Also 7 of the isolates (269%) were resistant to Clindamiycin, 3 (115%) to Quinupristion/ Dalfopristin and 1 strain to Teicoplanin, Vancomycin, Tetracycline and Fusic acid, respectively

Quinpristin-Dalfopristin resistance among methicillin-resistant strains of staphylococci.

Abstract: I have read the case report “Emergence of Pristinamycin resistance in India” by Keshari et al[1] The authors have reported two cases of neonatal septicemia, caused by Methicillin-resistant Staphylococcus aureus (MRSA), showing primary in vitro pristinamycin resistance. We would like to share our observations with the readership of the IJP. Methicillin resistant Staphylococcus aureus has become an important nosocomial pathogen. Glycopeptides have been the drugs of choice for treating MRSA infections. However, with the emergence of intermediate susceptibility to glycopeptides, other treatment alternatives, such as, quinpristin–dalfopristin and linezolid have become important. Quinpristin–dalfopristin is a combination of streptogramin B and A compounds with a synergistic activity against most gram-positive bacteria.[2] Quinpristin-dalfopristin is approved in the United States for treatment of infections caused by vancomycin-resistant strains of E. faecium and skin infections caused by MRSA and Streptococcus pyogenes. In Europe, it is also being used in the treatment of nosocomial pneumonia and other infections caused by MRSA. We have isolated a total of 63 Staphylococci from blood cultures in the last six months. The blood cultures were processed by the automated and computerized blood culture system (BACTEC BD). The blood culture medium used was trypticase soya broth. Positive blood samples were subcultured and their growth was identified by standard biochemical reactions. Antibiotic sensitivity was conducted with the help of the API-BioMerieux machine. This instrument used a computer-assisted analysis of growth in plastic cards to calculate the minimum inhibition concentration (MIC). The ATB STAPH strip was designed following the National Committee for Clinical Laboratory Standards (NCCLS) / Clinical and Laboratory Standards Institute (CLSI) recommendations.[3–5] Out of 38 Staphylococcus aureus isolated from the blood samples, 17 were MRSA. Three MRSA were found to be resistant to vancomycin (MIC > 16 mg/l), teicoplanin, and to quinpristin-dalfopristin (MIC > 2 mg/l). Out of the 17 MRSA, 14 showed sensitivity to vancomycin and quinpristin-dalfopristin. A total of 25 Coagulase negative staphylococci (CONS) were isolated from the blood samples. Out of nine methicillin-resistant CONS, four were detected to be vancomycin, teicoplanin, and quinpristin–dalfopristin resistant. All these seven vancomycin, quinpristin-dalfopristin-resistant staphylococci were isolated from the blood samples of neonates and pediatric patients. Out of these 63 isolates of staphylococci, 61 were found to be sensitive to minocycline. One interesting observation was that all the seven resistant isolates were sensitive to minocyclin [Table 1]. Table 1 Antibiotic resistance pattern of Staphylococci isolated from clinical samples Although vancomycin and quinpristine–dalfopristin have been recommended as alternative treatments for MRSA, Staphylococci resistant to qinpristin–dalfopristin have been reported. Deep et al. studied the drug resistance of Staphylococci in north India.[6] They isolated 54% MRSA and 64% quinpristin–dalfopristin resistant Staphylococcus aureus from pus and urine samples. Four quinpristin–dalfopristin resistant CONS were also reported. Our findings are similar to your report. Quinpristin–dalfopristin is not used routinely in our hospital for treatment. Infections by gram-positive cocci are becoming more difficult to treat, because of the rapid emergence of antibiotic resistance. Many MRSA and MRCONS are found to be sensitive to quinpristin–dalfopristin. We also agree that more comprehensive region-wise laboratory work is needed, before advocating this drug for multidrug–resistant, gram-positive infections.

Comparison of Antimicrobial Agents as Therapy for Experimental

Abstract: We used an experimental rat model to compare the therapeutic efficacy of teicoplanin, linezolid, and quinupristin/dalfopristin with that of vancomycin as standard therapy for in-fective endocarditis.Aortic endocarditis was induced in rats by insertion of a polyethylene catheter into the left ventricle, followed by intravenous inoculation of 10

Evaluation of MicroScan Synergies plus Positive Combo 3 Panels for Identification and Antimicrobial Susceptibility Testing of Staphylococcus aureus and Enterococcus Species

Abstract: Background : Few studies have evaluated the performance of the recently introduced MicroScan Synergies plus Positive Combo 3 Panels (SIPC3) (Dade Behring Inc., USA). We evaluated the clinical efficacy of the panels in identification (ID) and antimicrobial susceptibility testing (AST) of Staphylococcus aureus and enterococci. Methods : To evaluate the panels’ accuracy of identification, the results obtained using the test panels were compared with those obtained by using conventional biochemical tests in conjunction with VITEK 2 system (bio-Merieux, USA). In addition, the AST results obtained using the panels were compared with those obtained by performing CLSI broth microdilution. Results : The overall agreement between the approaches for the ID of S. aureus and enterococci was 100% and 96%, respectively. The categorical and essential agreements (CA and EA) for S. aureus were 98%, each. Very major errors (VME), major errors (ME), and minor error (mE) for S. aureus were 0.45%, 0.3%, and 4.2%, respectively. The majority of VMEs were for oxacillin (8.6%), penicillin (2.0%), erythromycin (7.9%), clindamycin (3.8%), and tetracycline (4.1%). For enterococci, the CA, EA, VME, ME, and mE were 88.8%, 93.7%, 4.4%, 0%, and 2.8%, respectively. The 80.5% (29/36) of Enterococcus faecium had concordant ID with the reference. Most of the categorical errors (3 VMEs and 14 mEs) were observed for quinupristin/dalfopristin (Synercid; Catalytica Pharmaceuticals Inc., USA). Conclusions : The panels compared favorably with conventional methods for the ID and AST of S. aureus. However, we expected a better performance for ID of E. faecium and AST using Synercid. (Korean J Lab Med 2010;30:373-80)