Murat Telli

Antimicrobial Resistance in Gram-Negative Hospital Isolates: Results of the Turkish HITIT-2 Surveillance Study of 2007

Abstract Resistance rates to amikacin, ciprofloxacin, ceftazidime, cefepime, imipenem, cefoperazone/sulbactam and piperacillin/tazobactam in Escherichia coli (n= 438)Klebsiella pneumoniae (n= 444)Pseudomonas aeruginosa (n= 210) and Acinetobacterbaumanni (n=200) were determined with e-test in a multicenter surveillance study (HITIT-2) in 2007. ESBL production in Escherichia coli and K. pneumoniae was investigated following the CLSI guidelines. Overall 42.0% of E.coli and 41.4% of K. pneumoniae were ESBL producers. In E. coli, resistance to imipenem was not observed, resistance to ciprofloxacin and amikacin was 58.0% and 5.5% respectively. In K. pneumoniae resistance to imipenem, ciprofloxacin and amikacin was 3.1%, 17.8% 12.4% respectively. In P. aeruginosa the lowest rate of resistance was observed with piperacillin/tazobactam (18.1%). A. baumanni isolates were highly resistant to all the antimicrobial agents, the lowest level of resistance was observed against cefoperazone/sulbactam (52.0%) followed by imipenem (55.5%). This study showed that resistance rates to antimicrobials are high in nosocomial isolates and show variations among the centers.

Acinetobacter dijkshoorniae sp. nov., a new member of the Acinetobacter calcoaceticus-Acinetobacter baumannii complex mainly recovered from clinical samples in different countries.

The recent advances in bacterial species identification methods have led to the rapid taxonomic diversification of the genus Acinetobacter. In the present study, phenotypic and molecular methods have been used to determine the taxonomic position of a group of 12 genotypically distinct strains belonging to the Acinetobacter calcoaceticus-Acinetobacter baumannii (ACB) complex, initially described by Gerner-Smidt and Tjernberg in 1993, that are closely related to Acinetobacter pittii. Strains characterized in this study originated mostly from human samples obtained in different countries over a period of 15 years. rpoB gene sequences and multilocus sequence typing were used for comparisons against 94 strains representing all species included in the ACB complex. Cluster analysis based on such sequences showed that all 12 strains grouped together in a distinct clade closest to Acinetobacter pittiithat was supported by bootstrap values of 99 %. Values of average nucleotide identity based on blast between the genome sequence of strain JVAP01T (NCBI accession no. LJPG00000000) and those of other species from the ACB complex were always <91.2 %, supporting the species status of the group. In addition, the metabolic characteristics of the group matched those of the ACB complex and the analysis of their protein signatures by matrix-assisted laser desorption ionization time-of-flight MS identified some specific peaks. Our results support the designation of these strains as representing a novel species, for which the name Acinetobacter dijkshoorniae sp. nov. is proposed. The type strain is JVAP01T (=CECT 9134T=LMG 29605T).

Prevalence of enterotoxins among Escherichia coli isolates causing bacteraemia

The most frequent cause of bacteraemia among Gram-negative bacteria is Escherichia coli. Analysis of the genes encoding the Shigella enterotoxin 1 (ShET-1), ShET-2, enteroaggregative heat stable toxin 1 (EAST-1) toxins and AggR factor in E. coli strains causing bacteraemia revealed that set1 genes were presented significantly more frequently among quinolone-susceptible strains (P<0.0001), in phylogenetic group B2 (P=0.0004) and in biofilm strains (P=0.02). In contrast, sen genes were significantly more frequent among nalidixic acid-resistant isolates (15% vs. 6%, P=0.046) and in phylogenetic group B1 (P=0.0001). This is the first study in which ShET1, ShET2 and EAST-1 have been found in E. coli collected from blood.

Evaluation of resistance mechanisms and serotype and genotype distributions of macrolide-resistant strains in clinical isolates of Streptococcus pneumonia in Aydın, Turkey

Macrolide resistance mechanisms in 89 Streptococcus pneumoniae strains isolated from several clinical samples between February 2007 and May 2009 were investigated. Erythromycin resistance was noted in 35 (40%) S. pneumoniae strains. In these strains, the most frequent resistance phenotype was cMLSB (74%), and the most frequent resistance genotype was ermB (82%). Both ermB and mefA genes were positive in 20% of macrolide-resistant strains. While no resistance to vancomycin, linezolid and telithromycin was noted in 89 S. pneumoniae strains, 12 (13%) strains were penicillin resistant, 26 (30%) strains were clindamycin resistant, 35 (40%) were azithromycin resistant, 32 (36%) strains were tetracycline resistant, and 1 (1%) strain was levofloxacin resistant. The serotype distribution of 35 macrolide-resistant S. pneumoniae strains revealed that the most frequent serotype was serogroup 19 (45%). Multidrug resistance was present in 19 (86%) of 22 strains carrying only the ermB resistance gene. No clonal dissemination was noted in the macrolide-resistant pneumococcal strains. These findings suggest that macrolide resistance rates, resistance phenotype and genotype, as well as resistant serotypes of S. pneumoniae strains should be continuously monitored in our country.

Identification of NDM-1 in a Putatively Novel Acinetobacter Species (“NB14”) Closely Related to Acinetobacter pittii

ABSTRACT In this study, we describe the molecular characterization of a plasmid-located blaNDM-1 harbored by an Acinetobacter clinical isolate recovered from a patient in Turkey that putatively constitutes a novel Acinetobacter species, as shown by its distinct ARDRA (amplified 16S ribosomal DNA restriction analysis) profile and molecular sequencing techniques. blaNDM-1 was carried by a conjugative plasmid widespread among non-baumannii Acinetobacter isolates, suggesting its potential for dissemination before reaching more clinically relevant Acinetobacter species.

Infecções relacionadas a cateteres torácicos

OBJECTIVE To determine the incidence of local and systemic infection in a sample of patients catheterized with thoracic catheters (TCs) and to identify the prognostic factors for catheter-related infection. METHODS A retrospective study involving 48 patients (17 females and 31 males) catheterized with TCs between December of 2008 and March of 2009 in the Thoracic Surgery Department of the Adnan Menderes University Hospital, located in Aydin, Turkey. Blood samples for culture were collected from the distal end of each TC and from each of the 48 patients. We looked for correlations between positive culture and possible prognostic factors for catheter-related infection. RESULTS Culture results were positive in TC samples only for 3 patients, in blood samples only for 2, and in both types of samples for another 2. Advanced age correlated significantly with positive culture in TC samples and in blood samples (r = 0.512 and r = 0.312, respectively; p < 0.05 for both), as did prolonged catheterization (r = 0.347 and r = 0.372, respectively; p < 0.05). There was a significant correlation between having undergone surgery and positive culture in TC samples only (p < 0.05). However, having an inoperable malignancy correlated with bacterial growth in blood and in TC samples alike (p < 0.05 for both). CONCLUSIONS Risk factors, such as advanced age, prolonged catheterization, comorbidities, and inoperable malignancy, increase the risk of catheter-related infection. It is imperative that prophylaxis with broad-spectrum antibiotics be administered to patients who present with these risk factors and might be catheterized with a TC.

Draft Genome Sequence of JVAP01T, the Type Strain of the Novel Species Acinetobacter dijkshoorniae

ABSTRACT Here, we report the draft genome sequence of the type strain of Acinetobacter dijkshoorniae, a novel human pathogen within the Acinetobacter calcoaceticus–Acinetobacter baumannii (ACB) complex. Strain JVAP01T has an estimated genome size of 3.9 Mb, exhibits a 38.8% G+C content, and carries a plasmid with the blaNDM-1 carbapenemase gene.