High-level Aminoglycoside Resistance In Enterococci Research Articles

Presence of genes encoding aminoglycoside-modifying enzyme (AME) and virulence factors in high-level aminoglycoside-resistant (HLAR) Enterococcus strains isolated from retail chicken meat in Turkey

In this study, the presence of aminoglycoside-modifying enzyme (AME) and virulence factor genes were investigated in previously isolated 32 high-level aminoglycoside-resistant (HLAR) Enterococcus strains isolated from retail chicken meat in Turkey. At least one AME-encoding gene was detected in HLAR enterococci by polymerase chain reaction (PCR). The ant(6ʹ)-Ia was identified as the most prevalent (87.5%, 28/32) AME gene. The aph(3ʹ)-IIIa (78.13%, 25/32), ant(4ʹ)-Ia (68.75%, 22/32), aph(2ʹʹ)-Ib (62.5%, 20/32), aac(6ʹ)-Ie-aph(2ʹʹ)-Ia (21.88%, 7/32) and aph(2ʹʹ)-Ic (9.38%, 3/32) are the other detected AME-encoding genes in strains. The aph(2ʹʹ)-Id was found in none of the HLAR strains. The aph(2ʹʹ)-Ib and ant(6ʹ)-Ia were identified as the most frequently AME-encoding genes in high-level gentamicin-resistant (HLGR) and high-level streptomycin-resistant (HLSR) strains, respectively. Among the 32 HLAR strains, only E. faecalis MSE61.1 and E. avium MSE63.1 were found capable of hydrolyzing gelatine. All HLAR strains showed α-hemolytic activity except E. durans MG13.4 and E. casseliflavus MGM111.1, which were exhibited β- and γ-hemolytic activity, respectively. It was determined that all HLAR strains, except E. durans MGE13.1 and MGE63.1, contain at least one virulence factor gene. The efaAfm (87.5%, 28/32), acm (65.63%, 21/32) and gelE (37.5%, 12/32) were found to be the most prevalent virulence factor genes. HLAR enterococci strains that have the virulence factor genes may pose a risk to consumer health.

Characteristics of High-Level Aminoglycoside-Resistant Enterococcus faecalis Isolated from Bulk Tank Milk in Korea.

Simple SummaryAminoglycosides are used to treat various infections in veterinary and human medicine. However, with the emergence of high-level aminoglycoside resistance in human and food-producing animals, the synergism of aminoglycosides with beta-lactam or glycopeptide is being threatened. Moreover, the environmental mastitis-causing agent, enterococci, has emerged as a cause of nosocomial infection due to its antimicrobial resistance. Therefore, the purpose of this study was to investigate the characteristics of high-level aminoglycoside-resistant Enterococcus faecalis isolated from bulk tank milk in Korea. It showed that 185 (61.5%) isolates out of 301 were high-level aminoglycoside resistant, while 149 isolates were multidrug resistant.Enterococci, which are considered environmental mastitis-causing pathogens, have easily acquired aminoglycoside-resistant genes that encode various aminoglycoside-modifying enzymes (AME). Therefore, this study was conducted to compare the distribution of high-level aminoglycoside-resistant (HLAR) and multidrug-resistant (MDR) Enterococcus faecalis (E. faecalis) bacteria isolated from bulk tank milk in four dairy companies in Korea. Moreover, it analyzed the characteristics of their antimicrobial resistance genes and virulence factors. Among the 301 E. faecalis bacteria studied, 185 (61.5%) showed HLAR with no significant differences among the dairy companies. Furthermore, 129 (69.7%) of the 185 HLAR E. faecalis showed MDR without significant differences among companies. In contrast, HLAR E. faecalis from companies A, B, and C were significantly higher in resistance to the four classes than those in company D, which had the highest MDR ability against the three antimicrobial classes (p < 0.05). In addition, in the distribution of AME genes, 72 (38.9%) and 36 (19.5%) of the isolates carried both aac(6′)Ie-aph(2″)-la and ant(6)-Ia genes, and the ant (6)-Ia gene alone, respectively, with significant differences among the companies (p < 0.05). In the distribution of virulence genes, the ace (99.5%), efa A (98.9%), and cad 1 (98.4%) genes were significantly prevalent (p < 0.05). Thus, our results support that an advanced management program by companies is required to minimize the dissemination of antimicrobial resistance and virulence factors.

Increasing relevance of Gram-positive cocci in urinary tract infections: a 10-year analysis of their prevalence and resistance trends

Urinary tract infections (UTIs) are the third most common types of infection in human medicine worldwide. There is increasing appreciation for the pathogenic role of Gram-positive cocci (GPC) in UTIs, as they have a plethora of virulence factors, maintaining their pathogenicity and high affinity for the epithelial cells of the urinary tract. The study was carried out using microbiological data collected corresponding to the period between 2008 and 2017. Antimicrobial susceptibility testing was performed using the disk diffusion method and E-tests. The age range of patients affected from the outpatient and inpatient groups differed significantly (43 [range 0.7–99] vs. 68 [range 0.4–99] years; p = 0.008). 3962 GPCs were obtained from inpatient and 4358 from outpatient samples, corresponding to 20.5 ± 2.8% (range 17.5–26.8%) and 20.6 ± 2.6% (range 17.8–26.0%) of all positive urine samples (p > 0.05); in both groups, Enterococcus spp. were the most prevalent (outpatients: 79.6%; inpatients: 88.5%). High-level aminoglycoside resistance in enterococci was noted in 31.0–46.6% of cases. A pronounced increase in the number of MRSA was seen in the second half of the study period (0.6–1.9% vs. 9.8–11.6%; p = 0.038). The ratio of VRE isolates was 0.16%, no VISA/VRSA isolates were detected.

Isolation, characterization, and comparative genomic analysis of a phage infecting high-level aminoglycoside-resistant (HLAR) Enterococcus faecalis.

Enterococcus is a genus of Gram-positive bacteria that are commensal to the gastrointestinal tracts of humans but some species have been increasingly implicated as agents of nosocomial infections. The increase in infections and the spread of antibiotic-resistant strains have contributed to renewed interest in the discovery of Enterococcus phages. The aims of this study were (1) the isolation, characterization, and genome sequencing of a phage capable of infecting an antibiotic-resistant E. faecalis strain, and (2) the comparative genomic analysis of publicly-available Enterococcus phages. For this purpose, multiple phages were isolated from wastewater treatment plant (WWTP) influent using a high-level aminoglycoside-resistant (HLAR) E. faecalis strain as the host. One phage, phiNASRA1, demonstrated a high lytic efficiency (∼97.52%). Transmission electron microscopy (TEM) and whole-genome sequencing (WGS) showed that phiNASRA1 belongs to the Siphoviridae family of double-stranded DNA viruses. The phage was approximately 250 nm in length and its complete genome (40,139 bp, 34.7% GC) contained 62 open reading frames (ORFs). Phylogenetic comparisons of phiNASRA1 and 31 publicly-available Enterococcus phages, based on the large subunit terminase and portal proteins, grouped phage by provenance, size, and GC content. In particular, both phylogenies grouped phages larger than 100 kbp into distinct clades. A phylogeny based on a pangenome analysis of the same 32 phages also grouped phages by provenance, size, and GC content although agreement between the two single-locus phylogenies was higher. Per the pangenome phylogeny, phiNASRA1 was most closely related to phage LY0322 that was similar in size, GC content, and number of ORFs (40,139 and 40,934 bp, 34.77 and 34.80%, and 60 and 64 ORFs, respectively). The pangenome analysis did illustrate the high degree of sequence diversity and genome plasticity as no coding sequence was homologous across all 32 phages, and even ‘conserved’ structural proteins (e.g., the large subunit terminase and portal proteins) were homologous in no more than half of the 32 phage genomes. These findings contribute to a growing body of literature devoted to understanding phage biology and diversity. We propose that this high degree of diversity limited the value of the single-locus and pangenome phylogenies. By contrast, the high degree of homology between phages larger than 100 kbp suggests that pangenome analyses of more similar phages is a viable method for assessing subclade diversity. Future work is focused on validating phiNASRA1 as a potential therapeutic agent to eradicate antibiotic-resistant E. faecalis infections in an animal model.

Detection of antibiotic resistance profiles and aminoglycoside-modifying enzyme (AME) genes in high-level aminoglycoside-resistant (HLAR) enterococci isolated from raw milk and traditional cheeses in Turkey.

The aim of this study was isolation and identification of the high-level aminoglycoside-resistant (HLAR) enterococci in raw milk and dairy products and to analyze their antibiotic resistance and the presence of aminoglycoside-modifying enzyme (AME) genes. A total of 59 HLAR enterococci were isolated from raw milk and traditional cheese samples. Thirty-nine of the 59 HLAR enterococci were isolated on streptomycin-containing agar medium, while the other 20 HLAR strains were isolated on gentamicin containing agar medium. The 59 HLAR enterococci were identified as 26 E. faecalis (44.07%), 18 E. faecium (30.51%), 13 E. durans (22.03%), and two E. gallinarum (3.39%) by species-specific PCR. Disk diffusion tests showed that teicoplanin were the most effective antibiotics used in this study, while 89.83% of isolates were found to be resistant to tetracycline. High rates of multiple antibiotic resistance were detected in HLAR isolates. Minimum inhibitory concentration (MIC) values of HLAR enterococci against streptomycin and gentamicin were found in the range of 64 to > 4096 µg/mL. Forty-seven (79.66%) of the 59 HLAR enterococci were found to be both high-level streptomycin-resistant (HLSR) and high-level gentamicin-resistant (HLGR) by MIC tests. However, no correlation was found between the results of the disk diffusion and MIC tests for gentamicin and streptomycin in some HLAR strains. The aph(3')-IIIa (94.92%) was found to be most prevalent AME gene followed by ant(4')-Ia (45.76%), ant(6')-Ia (20.34%) and aph(2'')-Ic (10.17%). None of the isolates contained the aac(6')-Ie-aph(2'')-Ia, aph(2'')-Ib or aph(2'')-Id genes. None of the AME-encoding genes were identified in E. durans RG20.1, E. faecalis RG22.4, or RG26.1. In conclusion, HLAR enterococci strains isolated in this study may act as reservoirs in the dissemination of antibiotic resistance genes.

Genetic characterization of high-level aminoglycoside-resistant Enterococcus faecalis and Enterococcus faecium isolated from retail chicken meat

Retail chicken meat can play a role in the transfer of drug resistance to humans through the handling or ingestion of improperly cooked meat contaminated with resistant enterococci. In fact, high-level aminoglycoside-resistance (HLAR) in enterococci identified in human cases. Therefore, the prevalence and genetic characterization of HLAR in enterococci in retail chicken meat were investigated in this study. Of the 345 enterococci strains, 29 (8.7%) showed HLAR. All HLAR in enterococci carried at least 1 of 2 aminoglycoside-modifying enzyme genes, aac(6')Ie-aph(2″)-Ia and ant(6)-Ia. Among the 13 isolates that carried aac(6')Ie-aph(2″)-Ia, 3 had pattern A, with IS256 at both ends, and the other 10 had pattern D, without IS256 at both ends. All HLAR in enterococci also showed multidrug resistance. Among the 24 erythromycin-resistant enterococci, 19 (79.2%) harbored the ermB gene, and one (4.2%) harbored both the ermB and ermA genes. A total of 21 enterococci were tetracycline-resistant and harbored one or more of the following tetracycline resistance genes tet(M), tet(L), and tet(O). The Int-Tn gene was detected in one isolate (3.4%) carrying the tet(M) and ermB genes. All 4 chloramphenicol-resistant isolates carried either the phenicol resistance gene cfr alone (one isolate), both cfr and fexA (one isolate), or both fexA and optrA (2 isolates). Four efflux pump genes, efr(A), efr(B), emeA, and lsa, were detected in all HLAR in Enterococcus faecalis isolates. These results improve our understanding of the transmission dynamics of HLAR in enterococci from non-hospital sources to humans.

INVESTIGATION OF VIRULENCE FACTORS USING PHENOTYPIC AND GENOTYPIC METHODS IN HIGH-LEVEL AMINOGLYCOSIDE RESISTANT ENTEROCOCCI ISOLATED FROM CHEESE

Bu çalışmanın amacı daha önce peynir örneklerinden izole edilen yüksek-seviyede aminoglikozid dirençli (YSAD) 54 enterokok izolatında virülens faktörlerin fenotipik ve genotipik yöntemler kullanılarak araştırılmasıdır. YSAD enterokok izolatlarında α-hemolitik (48.15 %), γ-hemolitik (46.30 %), ve β-hemolitik (5.55 %) aktivite fenotipik olarak belirlendi. Jelatinaz aktivitesi yalnız E. faecalis RG22.4, RG26.1 ve RG26.2 suşlarında tespit edildi. Polimeraz zincir reaksiyonu (PZR) ile E. faecium RS32.2 hariç YSAD enterokok izolatlarında en az bir virülens genin varlığı belirlendi. YSAD enterokok izolatlarında en sık görülen genlerin ccf (% 88.89), efaAfs (% 85.19), acm (% 77.78), gelE (% 59.2), cpd (% 51.85) ve espfs (% 50) olduğu tespit edildi. Fenotipik ve genotipik testler sonucu, 30 YSAD enterokok izolatında sessiz gelE geni bulundu. Peynirden izole edilen YSAD enterokok suşlarında yüksek sıklıkla virülens faktör genlerinin tespit edilmesi tüketici sağlığı için endişe uyandırıcıdır.

Study of vancomycin and high-level aminoglycoside-resistant Enterococcus species and evaluation of a rapid spot test for enterococci from Central Referral Hospital, Sikkim, India.

BACKGROUND:Enterococcus is an important pathogen, and with its emergence of resistance to multiple antimicrobials, the management of infection is becoming increasingly difficult.AIM:The aim of the study is to determine the prevalence, antibiotic resistance, and risk factors associated with enterococcal infection or colonization.MATERIALS AND METHODS:In this prospective study, samples from inpatients were screened for resistant enterococci. Antibiotic susceptibility testing was performed using the disc diffusion method and minimum inhibitory concentration by the agar dilution method. A modification of a test tube method of sodium chloride-esculin hydrolysis to a spot test was evaluated for its rapidity and reliability in the presumptive diagnosis of enterococci.STATISTICAL ANALYSIS USED:Fisher's exact test was used for continuous (Student's t-test) and categorical variables. Multivariate analysis was performed with logistic regression using IBM SPSS 20.0 software (Armonk, NY, USA).RESULTS:Enterococcus species were isolated from 182 samples: Enterococcus faecalis (68.7%), Enterococcus faecium (20.9%), Enterococcus gallinarum (6%), and Enterococcus durans (4.4%). Maximum resistance was to ciprofloxacin (59.3%) and least to linezolid (0.5%). The isolation rate of vancomycin-resistant enterococci (VRE) was 13.7%; 30.2% and 20.9% were of high-level gentamicin and streptomycin, respectively. All 182 Enterococcus species gave positive results within 30–60 min by the rapid spot test.CONCLUSIONS:Overall, high-level aminoglycoside resistance (HLAR) was observed more than glycopeptide resistance. Surveillance strategies need to be upgraded and implemented in order to prevent the emergence and further spread of not only VRE but also HLAR enterococci in the hospital. The spot test gave reliable and rapid results in presumptive identification of enterococci.

High level aminoglycoside resistant enterococci in hospital-acquired urinary tract infections in Mansoura, Egypt.

Resistance to different antimicrobial agents is increasing in enterococci and effective treatment represents a major health concern. The aim of this study was to determine the antimicrobial resistance patterns and the frequency of high level aminoglycoside resistance (HLAR) among enterococci. A total of 80 enterococcal isolates, (73 Enterococcus faecalis, 7 Enterococcus faecium) were collected from patients with hospital acquired urinary tract infections (UTI) at Mansoura University hospitals in Egypt. Antimicrobial susceptibility testing was performed via the disc diffusion method. PCR was used for identification of species and detection of aminoglycoside-modifying enzymes genes (AME). All enterococcal isolates were sensitive to vancomycin and linezolid. Fifty-three isolates exhibited HLAR. Our results show that HLAR was mediated by the presence of multiple AMEs genes. The aac(6')-Ie-aph(2')-Ia gene was associated with aph(3')-IIIa and ant(6)-Ia gene in 69% of HLAR isolates. This study showed that enterococci isolated from hospital acquired UTI were resistant to multiple antibiotics. Furthermore, the frequency of high level gentamicin resistance (HLGR) was higher than high level of streptomycin resistance (HLSR). The most common AME genes were aph(3')-IIIa and ant(6)-Ia followed by aac(6')-Ie-aph(2')-Ia.

A study on high level aminoglycoside resistant enterococci isolated from urinary tract infection

A study on high level aminoglycoside resistant enterococci isolated from urinary tract infection

Susceptibility to disinfectants in antimicrobial-resistant and -susceptible isolates of Escherichia coli, Enterococcus faecalis and Enterococcus faecium from poultry-ESBL/AmpC-phenotype of E.coli is not associated with resistance to a quaternary ammonium compound, DDAC.

The spread of bacteria that are simultaneously resistant to disinfectants and antimicrobials would constitute an unsettling scenario. In order to explore an association between antimicrobial resistance and reduced susceptibility to biocides/microbicides (disinfectants) in agriculture, we investigated Escherichia coli (n=438) and enterococci (n=120) isolated from six different flocks of the same poultry farm with known history of antimicrobial treatment. Susceptibility to disinfectants (formic acid and a quaternary ammonium compound (QAC), didecyldimethylammoniumchloride-DDAC) was assessed by macrodilution according to guidelines of the German Veterinary Society. Escherichia coli, Enterococcus faecalis and Enterococcus faecium were screened (i) for reduced biocide susceptibility and (ii) for an association of biocide susceptibility and antimicrobial resistance including the production of extended-spectrum beta-lactamases (ESBL) and the hyperproduction of AmpC-type beta-lactamases. DDAC inhibited ESBL/AmpC(hyper)-producing E.coli (n=53) from poultry at similar or slightly lower inhibitory concentrations, compared with non-ESBL/AmpC strains (median MIC=0·36 vs 1·44mgl-1 ). In contrast, DDAC-MICs were positively correlated with several other antibiotic MICs (e.g. piperacillin and sulphamethoxazole+trimethoprim in E.coli, chloramphenicol in E. faecalis) and increased DDAC-MICs were statistically linked to high-level aminoglycoside resistance in enterococci (streptomycin high level). DDAC-MICs did not correlate with the presence of the integron marker qacEDelta1. This study provides indication that residual disinfectant might be able to select antimicrobial-resistant enterococci, but not ESBL-/AmpC (hyper)producing E.coli from poultry. While ESBL-/AmpC-E.coli were inhibited at disinfectant concentrations comparable to or lower than wildtype values, low concentrations of QACs might be able to select other antimicrobial-resistant E.coli or enterococci-a finding with special significance for the food processing industry, where QACs are regularly used.

Early in vitro development of daptomycin non-susceptibility in high-level aminoglycoside-resistant Enterococcus faecalis predicts the efficacy of the combination of high-dose daptomycin plus ampicillin in an in vivo model of experimental endocarditis

Previous studies showed development of daptomycin non-susceptibility (DNS: MIC >4 mg/L) in Enterococcus faecalis infections. However, no studies have assessed the efficacy of the combination of daptomycin/ampicillin against E. faecalis strains developing DNS in the experimental endocarditis (EE) model. To assess the in vitro and in vivo efficacy of daptomycin at 10 mg/kg/day, daptomycin/ampicillin and ampicillin/ceftriaxone against two high-level aminoglycoside-resistant E. faecalis strains, one developing DNS after in vitro exposure to daptomycin and another that did not (DS). Subculture of 82 E. faecalis strains from patients with endocarditis with daptomycin MICs, time-kill and in vivo experiments using the EE model. 33% of the strains (27 of 82) displayed DNS after subculture with daptomycin. Daptomycin MIC rose from 0.5-2 to 8-16 mg/L. In time-kill experiments, when using a high inoculum (10 8 cfu/mL), daptomycin/ampicillin was synergistic for one-third of DS strains and none of DNS strains, while ampicillin/ceftriaxone retained synergy in all cases. In the EE model, daptomycin did not significantly reduce cfu/g from vegetations compared with control against either strain, while daptomycin/ampicillin reduced significantly more cfu/g than daptomycin against the DS strain, but not against the DNS strain [2.9 (2.0-4.1) versus 6.1 (4.5-8.0); P = 0.002]. Ampicillin/ceftriaxone was synergistic and bactericidal against both strains, displaying the same activity as daptomycin/ampicillin against the DS strain. Performance of an Etest for daptomycin MIC after subculture with daptomycin inhibitory doses on strains of high-level aminoglycoside-resistant E. faecalis endocarditis may be an easy test to predict the in vivo efficacy of daptomycin/ampicillin.

English

Enterococci are a common cause of nosocomial infection and prevalence of antibiotic resistance among them is increasing. This study aimed to identify the prevalence of high level aminoglycoside resistant enterococci at Alexandria Main University Hospital. A total of 133 enterococci strains isolated from clinical specimens were all subjected to Bauer Kirby disc diffusion to detect antibiotic susceptibility pattern. High level aminoglycoside resistance (HLAR) and vancomycin resistance were confirmed by minimum inhibitory concentration (MIC). The HLAR enterococci were further identified by API 20 STREP to species level and nitrocefin test was used to detect beta lactamase production. Furthermore, polymerase chain reaction (PCR) for detection of gentamycin resistance was done to all HLGR enterococcal strains and for detection of vancomycin resistance genes. Among the 133 enterococcal isolates, 47 (35.3%) were found to be HLAR (31 Enterococcus faecalis, 13 Enterococcus faecium and 3 Enterococcus avium). They were all negative for beta lactamase production, 78.7% were erythromycin resistant, 63.8% resistant to doxycyclines, 51.06% to chloramphenicol, 46.8% to penicillin, 42.5% to rifampicin, and 40.4% to ampicillin. All HLAR enterococcal isolates were sensitive to Teigycyciln and Linezolid except one strain was resistant to linezolid. Urinary enterococcal isolates were also found to be 88.4, 84.6, 80.7 and 15.3% resistant to ciprofloxacin, levofloxacin, norfloxacin, and nitrofurantoin, respectively. Regarding PCR, all HLGR strains had Aac 6/)-Ie-aph (2//)-Ia gene except for 2 strains. It was found also that 3 HLAR enterococcal strains were vancomycin resistant, all of&nbsp; which were E. faecium with Van A genotype. HLAR enterococci constituted 35.3% from the total enterococci isolated during the period of study denoting the importance of these isolates as nosocomial pathogens. This situation obligates the clinical microbiologist to try to identify the most useful active antibiotic for treatment. On the other hand, physicians should use antibiotics appropriately and comply with the infection-control policies in an effort to prevent further spread of high level aminoglycoside resistant enterococci. Key words: Alexandria Egypt, enterococci, high level aminoglycoside resistance, aminoglycosides, gentamycin, antibiotic resistance, vancomycin.

Minimum inhibitory concentration values and problematic disk break points of tigecycline against vancomycin and/or high-level aminoglycoside-resistant enterococci

BackgroundTigecycline is a new, semisynthetic glycylcycline. It is active against important multidrug resistant pathogens. AimThe purpose of this study was to investigate the sensitivity of multidrug-resistant enterococci to tigecycline, and to test the correlation between the minimal inhibitory concentration (MIC) and disk diffusion methods. Materials and methodsThe antimicrobial sensitivity of 108 multidrug-resistant isolates, which included 52 vancomycin-resistant enterococci (VRE) and 56 high-level aminoglycoside-resistant (HLAR) enterococci, was tested by the E test, broth microdilution test and disk diffusion methods. ResultsAll of the isolates were sensitive to tigecycline, as determined by the E test and broth microdilution test. The MIC 90 value (0.19μg/mL) of tigecycline for HLAR enterococci was higher than that for VRE (0.094μg/mL). When results were evaluated according to species, the MIC values of tigecycline for Enterococcus faecalis were higher than those for the other species. Eleven (10.1%) isolates produced false resistance results (zone diameter ⩽15mm) by the disk diffusion method. These cases were classified as major errors. Eight (7.4%) isolates had intermediate sensitivity (sensitivity zone of 16 or 17mm), which were classified as minor errors. The major and minor error percentages of HLAR enterococci (14.2% major, 10.7% minor error) were higher than those of VRE (5.7% major, 3.8% minor error). These results indicate that tigecycline is effective against multidrug-resistant enterococci. The sensitivity of multidrug-resistant enterococci to tigecycline should be investigated by MIC methods. The disk diffusion method causes major errors, especially for HLAR enterococci.

Risk factors for colonization with ampicillin and high-level aminoglycoside-resistant enterococci during hospitalization in the ICU and the impact of prior antimicrobial exposure definition: a prospective cohort study

The aim of our prospective cohort study was to determine the incidence, genetic relatedness and risk factors for colonization with ampicillin and high-level aminoglycoside-resistant enterococci (ARHLARE) among patients hospitalized in the intensive care unit. During 15-month period, we included 105 patients. The only independent risk factor for ARHLARE colonization was days of cefotaxime/ceftriaxone therapy [odds ratio (OR): 1·13; 95% confidence interval (CI) 1·10–1·27; P = 0·045]. Patients with higher total use of antibiotics, patients on prolonged mechanical ventilation, and patients with urinary tract infection (UTI), were also found to be at increased risk to become colonized with ARHLARE. Pulsed-field gel electrophoresis suggested multifocal origin of the majority of the colonizing strains. Our results show that an increase in total antibiotic consumption for 10 defined daily doses (DDD)/patient increased the odds of colonization with ARHLARE for 36%. Further efforts to optimize antimicrobial use in high risk patients are proposed.

Mitral valve endocarditis with high level aminoglycoside resistant Enterococcus faecalis in breast cancer patient

Introduction: Enterococci represent the third most common cause of infective endocarditis, after streptococcus and Staphylococcus aureus, and are responsible for 5–20% of all cases of endocarditis. We present a rare case of native valve Enterococcus faecalis (E. faecalis) endocarditis of mitral valve in a breast cancer patient. Case Report: A 56­year­old breast cancer patient presented with complains of fever and found to have E. faecalis bacteremia. Echocardiogram showed mitral valve vegetations. This E. faecalis strain was also found to have high level aminoglycoside resistance (HLAR). She responded well to six weeks ampicillin and ceftriaxone combination therapy despite loss of aminoglycoside synergy. Conclusion: Most commonly observed risk factors for enterococcal endocarditis were rheumatic fever, valvular heart abnormalities, gastrointestinal neoplasia, surgery (dental surgery, cardiovascular surgery, and abdominal surgery), gastrointestinal procedures and diabetes. Left­sided enterococcal endocarditis in our patient responded well to combination

Do mobile phones of patients, companions and visitors carry multidrug-resistant hospital pathogens?

A cross-sectional study was conducted to determine bacterial colonization on the mobile phones (MPs) used by patients, patients' companions, visitors, and health care workers (HCWs). Significantly higher rates of pathogens (39.6% vs 20.6%, respectively; P = .02) were found in MPs of patients' (n = 48) versus the HCWs' (n = 12). There were also more multidrug pathogens in the patents' MPs including methicillin-resistant Staphylococcus aureus, extended-spectrum β-lactamase-producing Escherichia coli, and Klebsiella spp, high-level aminoglycoside-resistant Enterococcus spp, and carabepenem-resistant Acinetobacter baumanii. Our findings suggest that mobile phones of patients, patients' companions, and visitors represent higher risk for nosocomial pathogen colonization than those of HCWs. Specific infection control measures may be required for this threat.

Clinico-epidemiological profile and high-level aminoglycoside resistance in enterococcal septicemia from a tertiary care hospital in east Delhi

Background:Emergence of high-level aminoglycoside and glycopeptide resistance has significantly contributed to the mortality, particularly in serious enterococcal infections.Objectives:This study was aimed to determine the prevalence of high-level gentamicin resistance (HLGR), high-level streptomycin resistance (HLSR) and vancomycin resistance in enterococcal isolates recovered from patients with bacteremia.Materials and Methods:A total of 110 blood culture isolates of enterococci were recovered from septicemic patients. Routine antibiotic susceptibility testing was performed and screening for ampilcillin, high-level aminoglycoside resistance (HLAR) and high-level vancomycin resistance was done by agar screen method.Results:Out of 110 isolates, Enterococcus faecium accounted for 53% of these isolates, followed by Enterococcus fecalis (33%), Enterococcus casseliflavus (8%), Enterococcus raffinosus (4%) and Enterococcus dispar (2%). Resistance to ampicillin, HLGR, HLSR and HLAR was detected in 58%, 62%, 58% and 54% of the isolates, respectively. No isolate was resistant to vancomycin.Conclusion:This study illustrates the high prevalence of HLAR in enterococci from patients with septicemia in our region, which emphasizes the need to predict synergy between beta-lactams and aminoglycosides for management of enterococcal infections.

Ampicillin plus Ceftriaxone for High-Level Aminoglycoside-Resistant Enterococcus faecalis Endocarditis

Letters5 February 2008Ampicillin plus Ceftriaxone for High-Level Aminoglycoside-Resistant Enterococcus faecalis EndocarditisAkashdeep Singh, MD, DMAkashdeep Singh, MD, DMFrom Christian Medical College and Hospital, Ludhiana, India 141008.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-148-3-200802050-00012 SectionsAboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail TO THE EDITOR:The antimicrobial synergism of ampicillin plus ceftriaxone to treat high-level aminoglycoside-resistant (HLAR) Enterococcus faecalis endocarditis, as shown by Gavaldà and colleagues (1), is important. However, certain basic questions need to be answered before this treatment can be incorporated into everyday practice. First, enterococci are inherently resistant to cephalosporins, including ceftriaxone. Second, ampicillin and ceftriaxone are both β-lactam antibiotics with a common mechanism of action: inhibition of synthesis of the bacterial peptidoglycan cell wall. Antimicrobial agents acting on different targets may enhance the overall antimicrobial activity. How then can there be synergism between these 2 drugs? Treatment of ...

Etiological Agents of Bacteremia in the Early Period After Liver Transplantation

Bacteremia is one of the major infections in orthotopic liver transplantation (OLT). The study of 83 adults who underwent OLT from 2001 to 2004, included patients followed prospectively from the day of transplantation to 4 weeks after the procedure by bacteriological cultures. The microorganisms were investigated according to standard National Committee for Clinical Laboratory Standards (NCCLS) procedures. Blood samples were examined in 59 recipients (71.1%) before and in 76 patients (91.6%) during the month after transplantation. Among 249 investigated samples, 96 were positive, as cultured from 19 recipients before OLT and 48 patients afterward. The most common were Gram-positive cocci (n = 71) and coagulase-negative staphylococci (n = 52), including methicillin-resistant coagulase-negative staphylococci (MRCNS). Enterococcus spp. occurred in 9 isolates (high-level aminoglycoside-resistant enterococci [HLAR] strains were cultured). We cultured the Enterobacteriaceae family (n = 16 isolates) and (n = 15 isolates), Gram-negative nonfermenting rods some of which were extended spectrum beta-lactamase producing [ESBL(+)] strains. The predominance of Gram-positive cocci was caused by CNS, and the use of prophylaxis to reduce Gram-negative bacteria. The increased rate of isolation of bacteria with multidrug resistance (MDR) to antimicrobial agents may be due to their frequent use for prophylaxis of bacterial infections in OLT. These MDR bacterial strains caused severe BSI after OLT.