[show abstract][hide abstract] ABSTRACT: Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are significant causes of morbidity and mortality in hemodialysis patients, since those patients are highly susceptible to infections due to immune suppression. The aims of this study were to investigate the presence of HBV and HCV infections in chronic hemodialysis patients by serological and molecular methods, and to determine the rate of occult HBV infection and the viral genotypes. A total of 201 patients who were under hemodialysis due to end-stage renal disease, were retrospectively evaluated. The study involved the patients at three different centers in Antalya, Turkey during 2006. HBV and HCV markers in the patients' sera were screened by ELISA method, viral nucleic acids were investigated by real-time polymerase chain reaction (PCR) in patients' plasma and viral genotypes were determined by DNA sequence analysis. Detection of at least one of the HBV markers HBsAg, anti-HBc total, and HBV DNA, was accepted as HBV infection, and detection of anti-HCV and/or HCV RNA was accepted as HCV infection. HBsAg positive patients with negative HBV DNA were considered as occult HBV infection. Of the patients 80 (40%) were female, 121 (60%) were male and the mean age was 51.16 ± 16.28 (range 17-93) years. In our study, sole anti-HBs positivity due to HBV vaccination, was detected in 89 (44.3%) patients. One hundred (50%) patients were found positive in terms of HBV infection and 40 (20%) were positive for HCV infection, while 24 (12%) patients had HBV and HCV co-infections. Eighty-five (42.3%) patients had no HBV and HCV infection. Among the 5 (2.5%) patients who were HBsAg positive, four were also HBV DNA positive. Occult HBV infection was detected in 1 (0.5%) patient. Anti-HCV and HCV RNA were found positive in 37 (18.4%) and in 24 (12%) patients, respectively. Among the HCV-RNA positive patients, 3 (12.5%) were anti-HCV negative. ALT and AST levels were found normal in all of the HBV DNA positive patients, and 62.5% (15/24) of HCV RNA positive patients. All of the HBV isolates were identifed as genotype D and HCV isolates as genotype 1b. No statistically significant correlation was detected between the HBV infection and patients' age, duration of hemodialysis and elevation of serum transaminase levels (p> 0.05). On the other hand, HCV infection was seen to increase with age (p= 0.047). HCV infection showed a statistically significant increase with the duration of hemodialysis. HCV infection risk was increased in patients who were under hemodialysis for ≥ 25 months (p< 0.001, OR: 0224, 95% CI= 0089-0562). There was also a statistically significant correlation between the presence of HCV infection (anti-HCV and/or HCV RNA positive) and high levels of serum transaminases (p< 0.001). However, in two of the three cases who were anti-HCV negative and HCV RNA positive, serum transaminase levels were normal while the viral loads were high. Therefore to follow-up HCV infection in the hemodialysis patients, anti-HCV and serum transaminase levels may not be sufficient alone and these patients should be evaluated periodically for HCV RNA. In addition, the detection of occult HBV infection in one of the study patients, indicated that HBV DNA should also be investigated at regular intervals in the hemodialysis patients.
[show abstract][hide abstract] ABSTRACT: Active screening for vancomycin-resistant enterococci (VRE) using rectal specimens is recommended to limit the spread of antimicrobial resistance within certain high-risk populations. We evaluated the diagnostic performance of Vancomycin Resistance 3 Multiplexed Tandem PCR assay (AusDiagnostics, Australia), a rapid multiplex real-time PCR assay that detects vanA and/or vanB.
Two-hundred-and-eleven rectal swabs from Hematology and Oncology unit were submitted for VRE surveillance via direct detection of vanA and/or vanB by culture and by using Vancomycin Resistance 3 Multiplexed Tandem PCR assay. Enterococci were identified to the species level by using standard biochemical tests and BD Phoenix Automated Microbiology System (BD Diagnostic Systems, USA). Vancomycin susceptibility of enterococci was determined using Etest (BioMerieux, France).
Compared to the culture method, Vancomycin Resistance 3 Multiplexed Tandem PCR assay had a sensitivity of 84.0%, specificity of 98.8%, positive predictive value (PPV) of 91.3%, and negative predictive value (NPV) of 97.6%. The assay failed to detect 18 (8.5%) specimens because of the presence of PCR inhibitors; of the remaining 193 specimens, 25 (12.9%) were positive, 23 for vanA, and 2 for vanB. Although both sensitivity and specificity for vanA VRE was 100% compared to the culture method, all vanB-positive specimens tested negative by VRE culture.
Vancomycin Resistance 3 Multiplexed Tandem PCR assay is a rapid and laborsaving option for VRE surveillance for direct use on rectal swabs. However, the high rate of PCR failure owing to the inhibitors in the specimens and the low specificity for vanB should be considered when interpreting the results.
Annals of laboratory medicine. 09/2013; 33(5):326-30.
[show abstract][hide abstract] ABSTRACT: This study compared the performance of Brilliance VRE agar to bile-esculine-azide agar with 6 µg ml-1 vancomycin (BEAV agar) for detecting vancomycin-resistant enterococci (VRE) in rectal swab specimens. VRE surveillance cultures were obtained from patients at Akdeniz University Hospital between August and September 2010. Rectal swab specimens were inoculated onto BEAV agar and Brilliance VRE agar. Plates were incubated at 35 °C and were read at 24 h and 48 h. Presumptive VRE colonies on each medium were identified by colony morphology, Gram stain and biochemical tests. Species identification and antimicrobial susceptibility testing was performed using BD Phoenix System. The MICs of vancomycin and teicoplanin were also determined by Etest method. Carriage of the vanA or vanB gene was confirmed using Cepheid Xpert vanA/vanB real-time PCR assay. Growth characteristics combined with antimicrobial susceptibility testing results were used to calculate the sensitivity, specificity, positive predictive value and negative predictive value of each medium evaluated at 24 h and 48 h. Twenty strains of VRE, which were confirmed as vanA resistant E. faecium were isolated from 183 rectal swab samples. The sensitivity and specificity of Brilliance VRE agar were 95 and 87.1 % following 24 h of incubation, 100 and 80.4 % following 48 h of incubation, respectively in comparison to BEAV agar which was 65 % sensitive and 71.8 % specific at 24 h, and 100 % sensitive and 60.7 % specific at 48 h. Brilliance VRE agar is a reliable medium for screening and presumptive identification of vancomycin-resistant E. faecium from rectal swab specimens.
Journal of Medical Microbiology 01/2013; · 2.30 Impact Factor
[show abstract][hide abstract] ABSTRACT: Enterococci which are part of the commensal flora of the human gastrointestinal and genitourinary tracts, are increasing in importance as the cause of hospital-acquired infections. Identification of Enterococcus spp. at the species level is of great importance, for appropriate treatment of patients, infection control and to supply epidemiological data. Conventional methods for the identification of enterococcus isolates at species level is difficult and time consuming. Correct identification of enterococcus isolates in clinical microbiology laboratory by conventional methods is replaced by semi-automated or automated identification and molecular methods. The aim of this study was to evaluate the performance of Phoenix automated system (BD Diagnostic Systems, USA), API Rapid ID 32 Strep System (bioMerieux, France) and Enterococcus MGRADE LightCycler kit (Roche Molecular Biochemicals, Germany) used in real-time polymerase chain reaction (Rt-PCR), for the species level identification of enterococcus strains isolated from clinical specimens. A total of 90 vancomycin susceptible enterococci isolated from different patients were identified by all of the three commercial systems, together with conventional methods. Of the strains, 59 were identified as E.faecalis, 28 were E.faecium, and one of each as E.raffinosus, E.hirae and E.casseliflavus with conventional methods. One E.faecalis strain identified by the conventional system was identified as E.faecium by Phoenix system and one E.faecium strain as E.durans. One E.raffinosus strain identifed by the conventional method was identified as E.avium by API. Conventionally identified four E.faecalis strains were determined to be E.faecium by Rt-PCR and one E.faecium, one E.raffinosus and one E.casseliflavus as E.faecalis. Accordingly, the consistency of Phoenix, API Rapid ID 32 Strep and LightCycler Enterococcus MGRADE systems with the conventional methods were detected as 97.8% (88/90), 98.9% (89/90), and 92.2% (83/90), respectively. In conclusion, all of those three commercial assays are appropriate methods to be used for the identification of enterococci at the species level in the routine clinical microbiology laboratories, due to their high compliance with the conventional method, and their ability to yield the results at the same day.
[show abstract][hide abstract] ABSTRACT: The aim of this study was to determine whether vancomycin resistant Staphylococcus aureus (VRSA) and vancomycin intermediate susceptible S.aureus (VISA) strains were present among methicillin-resistant S.aureus (MRSA) strains isolated from patients hospitalised at intensive care units (ICU) of hospitals located at different regions of Turkey and to determine the minimum inhibitory concentration (MIC) values of teicoplanin, linezolid, tigecycline, quinupristin-dalfopristin and daptomycin, which are alternative drugs for the treatment of MRSA infections. A total of 260 MRSA clinical strains (isolated from 113 lower respiratory tract, 90 blood, 24 wound, 17 catheter, 13 nasal swabs, two urine and one CSF sample) were collected from nine health-care centers in eight provinces [Ankara (n= 52), Konya (n= 49), Antalya (n= 40), Istanbul (n= 7), Izmir (37), Diyarbakir (n= 15), Van (n= 12), Trabzon (n= 48)] selected as representatives of the seven different geographical regions of Turkey. Methicillin resistance was determined by cefoxitin disk diffusion in the hospitals where the strains were isolated and confirmed by oxacillin salt agar screening at the Refik Saydam National Public Health Agency. Screening for VISA and VRSA was conducted using the agar screening test and E-test. Susceptibility of the MRSA strains to other antibiotics was also determined by E-test method. None of the 260 MRSA strains were determined to be VRSA or VISA. All were susceptible to teicoplanin and linezolid, and susceptibility rates to daptomycin, tigecycline and quinupristin-dalfopristin were 99.6%, 96.9%, and 95%, respectively. Absence of VISA and VRSA among the MRSA strains surveyed currently seemed hopeful, however, continuous surveillance is necessary. In order to prevent the development of VISA and VRSA strains the use of linezolid, tigecycline, quinupristin-dalfopristin and daptomycin should be encouraged as alternative agents of treatment of MRSA infections.
[show abstract][hide abstract] ABSTRACT: Differentiation of Staphylococcus aureus (S. aureus) from coagulase-negative staphylococci is very important in blood stream infections. Identification of S. aureus and coagulase-negative staphylococci (CoNS) from blood cultures takes generally 18-24 h after positive signaling on continuously monitored automated blood culture system. In this study, we evaluated the performance of tube coagulase test (TCT), slide agglutination test (Dry Spot Staphytect Plus), conventional polymerase chain reaction (PCR) and LightCycler Staphylococcus MGrade kit directly from blood culture bottles to achieve rapid identification of S. aureus by using the BACTEC 9240 blood culture system.
A total of 129 BACTEC 9240 bottles growing gram-positive cocci suggesting Staphylococci were tested directly from blood culture broths (BCBs) with TCT, Dry Spot Staphytect Plus, conventional PCR and LightCycler Staphylococcus MGrade kit for rapid identification of S. aureus.
The sensitivities of the tests were 99, 68, 99 and 100%, respectively.
Our results suggested that 2 h TCT was found to be simple and inexpensive method for the rapid identification of S. aureus directly from positive blood cultures.
Indian journal of medical microbiology 01/2011; 29(1):42-6.
[show abstract][hide abstract] ABSTRACT: The identification of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) is becoming a hard task since colonization with MRSA is lasting for years and the number of the health care facilities other than hospitals is continuously increasing. In this study we aimed to investigate the genetic properties and health-care association of MRSA strains isolated from skin and soft tissue infections of outpatients admitted to Akdeniz University Hospital. Thirty strains were phenotypically identified as MRSA and after assessing the risk factors, 28 (93.3%) of them were classified as health-care associated (HCA) and 2 (6.7%) of them as community-acquired (CA). All of the isolates were positive for nuc and mecA genes by polymerase chain reaction. Antimicrobial resistance rates of HCA-MRSA and CA-MRSA isolates were found as follows, respectively; 89.3% and 0% for rifampin, 89.3% and 50% for ciprofloxacin, 89.3% and 0% for gentamicin, 50% and 50% for erythromycin, 28.6% and 0% for clindamycin, whereas all of the isolates were susceptible to vancomycin, linezolid and trimethoprim-sulfamethoxazole. SCCmec type III was detected in 24 (85.7%) of HCA-MRSA strains. SCCmec type IV was detected in 1 (3.6%) of HCA-MRSA and in 2 (100%) of CA-MRSA strains. Panton-Valentin leucocidin (PVL) gene positivity was detected in only CA-MRSA isolates (2/2; 100%). MRSA isolates were grouped into 17 different genotypes (from A to R) of which pulsotype A was predominant among HCA isolates and CA-MRSA isolates were found to be clonally related with each other. This is the first study which investigated the genetic properties of MRSA strains in Antalya (a province located at Mediterranean Region, Turkey). In this study HCA risk factors were investigated and CA-MRSA rate was only 6.7% among all MRSA strains isolated from outpatients. As a result of detailed investigation of HCA risk factors, it was possible to detect the exact rate of CA-MRSA among outpatients. Thus it is of clinical and epidemiological importance to know the origin of MRSA isolates since this will affect the empirical treatment choice. Genetic studies supplied by appropriate demographic data will help to clarify the evolution and epidemiology of MRSA in the community and in the hospital setting.
[show abstract][hide abstract] ABSTRACT: The aim of this study was to determine the extended-spectrum beta-lactamase (ESBL) types by isoelectric focusing (İEF) and polymerase chain reaction (PCR) methods in 56 Escherichia coli strains isolated from urine samples of patients with community-acquired urinary tract infection and determined as ESBL positive with the phenotypic screening tests (E test and combined disk method). IEF revealed that most of the strains produced 1 to 3 different bands, mostly at the isoelectric points 8.2 (n= 44, 79%) compatible with CTX-M. Twenty four (43%) isolates had CTX-M and TEM enzyme bands together, 16 (29%) isolates had only CTX-M enzyme bands, 3 (5%) isolates had CTX-M, TEM, SHV bands, one had CTX-M and SHV enzyme bands together, and one had only TEM band. Eleven E.coli strains did not yield any enzyme bands. PCR analysis revealed that 93% (n= 52) of the isolates had CTX-M, 64% (n= 36) had TEM and 11% (n= 6) had SHV, while 29 (52%) had CTX-M + TEM, three had CTX-M + SHV, and three had CTX-M + TEM + SHV genes together. PER-1 type beta-lactamases were not detected by PCR method. PCR analysis of the eleven strains that yielded no band in IEF showed that 5 strains had CTX-M + TEM, 3 had CTX-M and 3 had TEM enzyme genes. The consistency between IEF and PCR methods for the determination of CTX-M, TEM and SHV enzymes was 85%, 78% and 67%, respectively. Genes encoding ESBL's are usually located on transferrable plasmids that may also carry other resistance determinants. Thus detection of beta-lactamase enzyme types in ESBL positive bacteria is important for the choice of appropriate antimicrobial agents for treatment.
[show abstract][hide abstract] ABSTRACT: Imipenem and meropenem are broad spectrum antimicrobial agents that are especially useful in the treatment of nosocomially acquired Pseudomonas aeruginosa and Acinetobacter spp. infections. Previous reports have noted that susceptibility tests could show false resistance to imipenem. For this reason, Centers for Disease Control and Prevention has recommended that all carbapenem resistant or intermediate resistant isolates should be tested with an additional method to verify the results. This study was aimed to evaluate the imipenem and meropenem susceptibilities by disk diffusion, E-test and broth microdilution in P. aeruginosa and Acinetobacter baumannii strains found to be resistant or intermediate to imipenem-meropenem by BD Phoenix automated susceptibility testing system. Between January 2006-January 2007, 85 non-duplicate isolates of A. baumannii and 51 non-duplicate isolates of P. aeruginosa which were determined as resistant or intermediate resistant to imipenem and/or meropenem by BD Phoenix automated identification and susceptibility system (Becton Dickinson, Sparks, MD, USA) were collected in Akdeniz University Hospital Central Laboratory. All strains were tested by E-test (AB Biodisk, Sweden), disk diffusion and reference broth microdilution (BMD) method following CLSI recommendations. All 51 isolates of P. aeruginosa determined as imipenem and/or meropenem resistant or intermediate resistant by BD Phoenix, were found to be imipenem and/or meropenem resistant or intermediate resistant by the reference BMD method. Minor error rates were same for all testing systems (1.9%) except for the meropenem results of BD Phoenix system (5.9%). No major errors were produced by any system. For A. baumannii, only one very major error was detected for meropenem by BD Phoenix system. Number of minor errors determined for meropenem by all testing systems compared to the reference test, ranged from 2 (2.4%) to 3 (3.5%). It was concluded that carbapenem susceptibility test results obtained by BD Phoenix system for P. aeruginosa and A. baumannii isolates, could be reported without an additional susceptibility testing method unless indicated on case basis.
[show abstract][hide abstract] ABSTRACT: Despite growing concern about vancomycin-resistant enterococci (VRE) as nosocomial pathogens, especially in the USA, they have been rarely isolated in Turkish hospitals. After initial description in 2001 of unrelated VRE isolates, we report now the molecular characterization of a nosocomial outbreak at the Akdeniz University Hospital, Antalya, Turkey.
VRE isolates were from either clinical or rectal swab specimens. Identification, susceptibility testing and molecular characterization were performed according to standard techniques. Virulence genes (encoding aggregation substance, gelatinase, cytolysin, enterococcal surface protein and hyaluronidase) were sought by PCR.
Thirty-six VRE were isolated from 10 patients between June and October 2005 in the Department of Paediatrics. Six patients were only carriers, two had urinary tract infections and two had bloodstream infections. All isolates were Enterococcus faecium, of vanA genotype and belonged either to a main pulsotype (A) or to three minor pulsotypes (B, C and D). The epidemic strain A, found in eight patients, expressed high-level glycopeptide resistance (MIC of vancomycin 256 mg/L and MIC of teicoplanin 64 mg/L) and was of multilocus sequence typing sequence type (ST) 31, whereas the minor strain D, found in two patients, expressed heterogeneous glycopeptide resistance (MIC of vancomycin 8 to 256 mg/L) and was ST18. Strains B and C were only found in single patients either with strain A or alone. The two epidemic strains A and D were esp gene-positive. Their vanA genes were located on transposons similar to Tn1546, except for deletion of the transposition genes and the presence of IS1542, inserted upstream of the vanA operon, and IS1216, inserted at the 3' end of the vanX gene. VRE outbreak was contained by early identification and implementation of measures for patient isolation and of stringent hand and environmental disinfection policies.
This work underlines the emergence in Turkey of epidemic VRE clones that belong to the clonal complex-17 (CC-17) and that are esp-positive.
Journal of Antimicrobial Chemotherapy 06/2008; 61(5):1033-9. · 5.34 Impact Factor