Ali Riza Atasoy

A Multicenter Evaluation of Blood Culture Practices, Contamination Rates, and the Distribution of Causative Bacteria

Background: The prognostic value of blood culture testing in the diagnosis of bacteremia is limited by contamination. Objectives: In this multicenter study, the aim was to evaluate the contamination rates of blood cultures as well as the parameters that affect the culture results. Materials and Methods: Sample collection practices and culture data obtained from 16 university/research hospitals were retrospectively evaluated. A total of 214,340 blood samples from 43,254 patients admitted to the centers in 2013 were included in this study. The blood culture results were evaluated based on the three phases of laboratory testing: the pre-analytic, the analytic, and the post-analytic phase. Results: Blood samples were obtained from the patients through either the peripheral venous route (64%) or an intravascular catheter (36%). Povidone-iodine (60%) or alcohol (40%) was applied to disinfect the skin. Of the 16 centers, 62.5% have no dedicated phlebotomy team, 68.7% employed a blood culture system, 86.7% conducted additional studies with pediatric bottles, and 43.7% with anaerobic bottles. One center maintained a blood culture quality control study. The average growth rate in the bottles of blood cultures during the defined period (1259 - 26,400/year) was 32.3%. Of the growing microorganisms, 67% were causative agents, while 33% were contaminants. The contamination rates of the centers ranged from 1% to 17%. The average growth time for the causative bacteria was 21.4 hours, while it was 36.3 hours for the contaminant bacteria. The most commonly isolated pathogens were Escherichia coli (22.45%) and coagulase-negative staphylococci (CoNS) (20.11%). Further, the most frequently identified contaminant bacteria were CoNS (44.04%). Conclusions: The high contamination rates were remarkable in this study. We suggest that the hospitals’ staff should be better trained in blood sample collection and processing. Sterile glove usage, alcohol usage for disinfection, the presence of a phlebotomy team, and quality control studies may all contribute to decreasing the contamination rates. Health policy makers should therefore provide the necessary financial support to obtain the required materials and equipment.

Investigation of OprD Porin Protein Levels in Carbapenem-Resistant Pseudomonas aeruginosa Isolates.

Background: The Pseudomonas aeruginosa porin OprD is a substrate-specific porin that facilitates the diffusion of basic amino acids, small peptides, and carbapenems into the cell. OprD-mediated resistance occurs as a result of decreased transcriptional expression of oprD and/or loss of function mutations that disrupt protein activity. Objectives: In this study, we examined the level of oprD expression in P. aeruginosa clinical isolates to determine the contribution of OprD porins in carbapenem resistance. Materials and Methods: Included strains were divided into two groups, comprised of multidrug-resistant (MDR) and isolated carbapenem-resistant (ICR) strains. The transcription product level of oprD was identified using real-time polymerase chain reaction (qPCR). Results: Of the 18 clinical isolates, a decrease in the oprD level was found to be significant in 13 isolates. Nine of eighteen isolates with a significant decrease were determined in the first group and comprised MDR isolates that showed a statistically significant difference compared with the ICR group (P = 0.001). In the ICR group, oprD levels were found to be significantly low in 4 isolates. Six different patterns were determined by comparing band profiles in AP-PCR. Conclusions: Although the data support the idea that the basic mechanism of imipenem resistance could be via the loss of oprD, they do not fully explain the role of oprD and indicate that other mechanisms may play an important role. Additionally, the significant decrease in the oprD levels in MDR strains suggests that oprD also plays a role in the emergence of both carbapenem and non-carbapenem resistance.

Hepatitis C testing among adults born between 1945 and 1965 in Turkey: a multicentre study

OBJECTIVE Hepatitis C virus (HCV) infection is a major public health problem and affects large populations all over the world. Serum anti-HCV level is a valuable marker to determine HCV infection. Anti-HCV testing has been recommended for high-risk population. The Center for Disease Control (CDC) and Prevention in the United States proposed a new high-risk population group - adults born between 1945-1965. Under this perspective, we designed a multicentre retrospective study to determine the seropositivity of anti-HCV among adults born between 1945 and 1965 and adults born after 1965 in Turkey. With the data collected, we aimed to determine whether there was a need for anti-HCV testing especially in people born between 1945 and 1965. METHODS We requested data from ten different medical centres in ten different provinces. Each medical centre collected the anti-HCV test results of adult patients for five-year period between 2009 and 2014 from hospital records. RESULTS A total of 974,449 anti-HCV test results were included in this study. When the seropositivity rates in the two groups of adults were compared, anti-HCV seropositivity rates were higher in nine medical centres out of ten. Anti-HCV seropositivity in adults born between 1945-1965 was significantly higher than in adults born after 1965 (p < 0.05). CONCLUSIONS We determined that the anti-HCV seropositivity rate is significantly higher in adults born between 1945-1965 compared to the younger adults as indicated in the literature. According to data from this study together with the WHO and CDC suggestions, we believe that it is appropriate to offer anti-HCV serology testing for people over 50 years of age since the anti- HCV seroprevalence in this age group is relatively high.

Investigation of mutations in adeR and adeS gene regions in gentamicine resistant Acinetobacter baumannii isolates

ABSTRACT This study evaluated the relationship between aminoglycoside resistance and the active efflux pump and investigated the role of the active efflux pump in resistance mechanisms. In addition, the mutations related to aminoglycoside resistance were investigated in Acinetobacter baumannii isolates obtained from different clinical specimens. The study included 32 A. baumannii isolates. They were identified and their susceptibilities were determined using conventional techniques and an automated system. Total genomic RNA, DNA and cDNA were obtained using commercial extraction kits. Primers for adeR and adeS were designed using sequences in GenBank. All isolates were subjected to polymerase chain reaction (PCR) to determine the presence of adeR and adeS. The PCR products were electrophoresed for the optimization study. Subsequently, real-time PCR was performed to determine the expression levels of the adeR and adeS genes. Sequence analysis of the two adeRS operons in our isolates showed five mutations differing from those of other isolates. Isolate A21 had three mutations: (Tyr31Phe), (Val136Ala) and (Leu142Ile); isolate A24 had two mutations: (Asn115His) and (Leu142Ile). In our study, the examined gene regions that play a role in the resistance mechanisms of A. baumannii were considered important. The results indicated that adeR and adeS expression clearly affect aminoglycoside resistance. However, gene expression alone does not seem sufficient to explain that. These results could help to design improved active efflux pump inhibitors.