Tülin Güven Gökmen

Pseudomonas aeruginosa infections due to electronic faucets in a neonatal intensive care unit.

Aim:  To evaluate the role of electronic faucets in a newborn intensive care unit during a Pseudomonas aeruginosa outbreak.

COMPARISON OF 16S rRNA-PCR-RFLP, LipL32-PCR AND OmpL1-PCR METHODS IN THE DIAGNOSIS OF LEPTOSPIROSIS

SUMMARY Leptospirosis is still one of the most important health problems in developing countries located in humid tropical and subtropical regions. Human infections are generally caused by exposure to water, soil or food contaminated with the urine of infected wild and domestic animals such as rodents and dogs. The clinical course of leptospirosis is variable and may be difficult to distinguish from many other infectious diseases. The dark-field microscopy (DFM), serology and nucleic acid amplification techniques are used to diagnose leptospirosis, however, a distinctive standard reference method is still lacking. Therefore, in this study, we aimed to determine the presence of Leptospira spp., to differentiate the pathogenic L. interrogans and the non-pathogenic L. biflexa, and also to determine the sensitivity and specificity values of molecular methods as an alternative to conventional ones. A total of 133 serum samples, from 47 humans and 86 cattle were evaluated by two conventional tests: the Microagglutination Test (MAT) and the DFM, as well as three molecular methods, the 16S rRNA-PCR followed by Restriction Fragment Lenght Polymorphism (RFLP) of the amplification products 16S rRNA-PCR-RFLP, LipL32-PCR and OmpL1-PCR. In this study, for L. interrogans, the specificity and sensitivity rates of the 16S rRNA-PCR and the LipL32-PCR were considered similar (100% versus 98.25% and 100% versus 98.68%, respectively). The OmpL1-PCR was able to classify L. interrogans into two intergroups, but this PCR was less sensitive (87.01%) than the other two PCR methods. The 16S rRNA-PCR-RFLP could detect L. biflexa DNA, but LipL32-PCR and OmpL1-PCR could not. The 16S rRNA-PCR-RFLP provided an early and accurate diagnosis and was able to distinguish pathogenic and non-pathogenic Leptospira species, hence it may be used as an alternative method to the conventional gold standard techniques for the rapid disgnosis of leptospirosis.

NDM-1 and rmtC-Producing Klebsiella pneumoniae Isolates in Turkey

Background The resistance of aminoglycosides in strains that produce beta-lactamase can be developed through the multidrug resistant encoding genes carried by common plasmids. Recently, the association between 16S rRNA methyltransferase resistance and beta-lactamase enzymes carried by the same plasmids has drawn increased attention from researchers, particularly the association in aminoglycoside-resistant strains with a minimum inhibitory concentration (MIC) of ≥ 256 µg/mL. Objectives We aimed to investigate the co-existence of 16S rRNA methyltransferase and beta-lactamase genes in multidrug resistant (MDR) Klebsiella pneumoniae strains isolated from clinical samples. Methods We determined the molecular mechanisms of aminoglycoside resistance and its relationship with resistance to carbapenem and beta-lactam group antibiotics in 40 extended-spectrum beta-lactamase (ESBL)-positive carbapenem- and aminoglycoside-resistant K. pneumoniae strains. Multidrug resistant K. pneumoniae was isolated from various clinical samples in the faculty of medicine of Cukurova University, Turkey. First, the resistance of aminoglycoside and beta-lactam antibiotics was phenotypically investigated using the Kirby-Bauer disk diffusion test, double disk synergy test, and modified Hodge test. The MIC values of aminoglycoside were determined using the agar dilution method. Polymerase chain reaction was performed to detect the carbapenemases, ESBL, and 16S rRNA methyltransferase genes. The results were confirmed by a sequence analysis. Results Twenty K. pneumoniae strains showed resistance to amikacin, and 40 were resistant to gentamicin. The MIC value was found to be > 512 µg/mL in five amikacin-resistant strains and > 128 µg/mL in 10 gentamicin-resistant isolates. The rmtC gene, a type of 16S rRNA methyltransferase, was amplified in four isolates (MIC amikacin: > 512 µg/mL, gentamicin: > 128 µg/mL). Of these four isolates, three had the blaNDM-1 gene and all contained at least one ESBL gene. Conclusions This study demonstrated the co-existence of rmtC and blaNDM-1 genes for the first time in Turkey. The spread of this resistant type should be monitored and limited through molecular surveillance.

Molecular characterization of methicillin-resistant Staphylococcus aureus strains by spa typing and pulsed field gel electrophoresis methods

BackgroundRapid detection of sources and transmission routes by molecular methods provides key data for risk management of methicillin-resistant Staphylococcus aureus-induced infections acquired in both the community and hospitals. This study aimed to determine the clonal relationship of methicillin-resistant S. aureus strains isolated from our hospital by pulsed-field gel electrophoresis (PFGE) and Staphylococcal protein A (spa) typing methods and to identify the predominant clones in Cukurova Region, Turkey.ResultsAll isolates analyzed by PFGE were distributed among 11 clusters. Clusters A (n = 19) and B (n = 27) were 84.1% similar and accounted for 61% of all samples. All isolates were distributed among 18 spa types, with the most common type being t030 with 31 isolates (41.3%), followed by t223 with nine isolates (12%) and t127 with seven isolates (9.3%).ConclusionsWe found that t030 was the most common spa type in the area where the study was conducted, as also previously shown in studies undertaken in Turkey. However, the rate of t030 in our study was below the rates reported in the literature. We also detected some rare or sporadic spa types like t127, which has not been previously defined in our country. We consider that the spa typing and PFGE methods are useful for research on clonal relations in monitoring the changing prevalent clones in specific regions.

Molecular epidemiology of carbapenem-resistant Klebsiella pneumoniae at a Turkish centre: Is the increase of resistance a threat for Europe?

OBJECTIVES In recent years, carbapenem-resistant Klebsiella pneumoniae (CRKP) have become an important threat to hospitalised patients. This study aimed to identify the genetic mechanisms of carbapenem resistance in CRKP isolated from patients in a Turkish centre. METHODS During 2013-2014, a total of 98 K. pneumoniae isolated from patients at Çukurova University Balcalı Hospital (Adana, Turkey) determined phenotypically as resistant to carbapenems were screened genotypically for the presence of carbapenemase enzymes by multiplex PCR. RESULTS Of the 98 patients for whom genetic investigation was made, 93 (94.9%) were adults, 56 (57.1%) were male and 81 (82.7%) were diagnosed as infected. The mean and median age were 51.8±20.5years and 55 years (range 1-89 years), respectively. The nosocomial infection rate was 87.8% (86/98). The mortality rate was 41.8% (41/98). Fifty-eight patients (59.2%) were admitted to intensive care units. Of the 12 non-nosocomial infections, 5 (41.7%) originated from the inpatient clinic of the urology department. The mean and median hospital length of stay (LOS) were 20.7±20.8days and 17days (range 0-90 days), respectively. The most common carbapenemase gene detected was blaOXA-48 (74.5%), followed by blaVIM (45.9%) and blaSME (37.8%). The blaNDM gene was detected in 20 isolates (20.4%). The most effective antibiotics were tigecycline and colistin, with susceptibility rates of 87.5% and 74.3%, respectively. CONCLUSIONS Multiple resistance mechanisms were present in CRKP isolates in Turkey. Most of the isolates harboured blaOXA-48, blaVIM and blaSME genes; meanwhile, the rate of 20.4% for blaNDM is alarming.