Derya Aysev

Colistin is active against most multidrug-resistant, aerobic Gram-negative bacteria. Because of the reported nephrotoxicity during the first years of use of colistin, there were concerns of its use in pediatrics where there was limited experience The aim of this study is to document the clinical characteristics and outcomes of use of colistin in pediatric patients at a pediatric intensive care unit in Turkey. We reviewed the medical and laboratory records of 29 critically ill children who were treated with colistin for 38 courses between January 2011 and December 2011 at the Department of Pediatric Intensive Care Unit in Ankara University Medical School, Turkey. The median age was 17 months (range 3-217 months). Male-to-female ratio was 1:1.37. Ventilator-associated pneumonia (21 courses) was the leading diagnosis followed by catheter-related blood stream infection (6 courses), bacteremia (4 courses), ventriculoperitoneal shunt infection, peritonitis and pneumonia (1 course). The most commonly isolated microorganisms were Acinetobacter baumanni, Pseudomonas aeruginosa, Klebsiella pneumoniae, Serratia marcescens, Stenotrophomonas maltophilia, and Enterobacter cloacae. Two colistin formulations were used. Colimycin (Kocak Farma) was used in 21 colistin treatment episodes. The median dosage of colistin in this group was 5.0 mg/kg/d (2.3-5.6 mg/kg/d). Colomycin (Forest Laboratories) was used in 17 colistin treatment episodes. The median dosage of colistin in the second group was 75,000 International Unit/kg/d (50,000-80,000 International Unit/kg/d). Thirty colistin treatment episodes (79%) had a good or partial clinical response and 8 (21%) had a poor clinical response. Of the 8 colistin treatment episodes with poor clinical response, 3 were in the Colimycin group and 5 were in the Colomycin group. Ten patients died. There was no evidence of neurotoxicity in this study. Nephrotoxicity was observed in 1 patient but was not attributed to colistin because the patient had multiorgan failure at the same time. This study in a small cohort of patients suggests that the use of colistin in severe nosocomial infections caused by multidrug-resistant Gram-negative bacteria is well-tolerated and efficacious.

The purpose of this study was to investigate the effects of pneumococcal conjugate vaccine (PCV7) on nasopharyngeal (NP) carriage rates of Streptococcus pneumoniae in healthy Turkish children. The study was conducted on 1101 healthy Turkish children between 1 month and 18 years of age. The median and mean ages of the children were 25 months (1 month-18 years) and 45.7±49.6 months, respectively. S. pneumoniae was isolated in 241/1101 (21.9%) children included in the study. According to multivariate analysis, being

The aim of this study was to determine serotype distribution and investigate antimicrobial resistance patterns of Streptococcus pneumoniae in healthy Turkish children in the era of community-wide pneumococcal conjugate vaccine (PCV7). The study was conducted on 1,101 healthy children less than 18 years of age. Specimens were collected with nasopharyngeal swabs between April 2011 and June 2011. Penicillin and ceftriaxone susceptibilities were determined by E-test according to the 2008 Clinical Laboratory Standards Institute, and serotypes of the isolates were determined by Quellung reaction. The nasopharyngeal pneumococcal carriage rate was 21.9 % (241/1,101). Using the meningitis criteria of minimum inhibitory concentration values, 73 % of the isolates were resistant to penicillin and 47.7 % of them were resistant to ceftriaxone. Half of all pneumococcal isolates were serotyped as 19F (15.2 %), 6A (15.2 %), 23F (10.3 %), and 6B (9.3 %) and surprisingly, no serotype 19A was isolated. Serotype coverage rates of PCV7 and non-PCV7 were 46.2 and 53.8 %, respectively. The most common penicillin- and ceftriaxone-resistant serotypes were 6A, 6B, 14, 19F, and 23F. Penicillin- and ceftriaxone-resistant isolates were more prevalent in serotypes covered by PCV7 than the non-PCV7 serotypes. Conclusion: After the community-wide PCV7 vaccination, more non-PCV7 serotypes were isolated from the carriers compared to the time before PCV7 was used especially the serotype 6A, and the antimicrobial resistance of pneumococci was significantly increased.

Shigella is one of the most important causative agents of diarrhea especially in childhood. Since man is the main reservoir of Shigella and human to human transmission is possible, Shigella can easily spread in public and cause outbreaks. In this study, a total of 60 Shigella strains isolated in Ankara, Turkey by years 2001, 2008 and 2009 were investigated by their antimicrobial susceptibility profiles, plasmid profile analysis (PPA) and pulsed-field gel electrophoresis (PFGE). For epidemiological investigation, the results obtained by antibiotic resistance typing (ART) which was the phenotyping method, was compared to the results of the genotyping methods which were PPA and PFGE. Of the isolates 49 (81.6%) were S.sonnei, 10 (16.6%) were S.flexneri and one was (1.6%) S.dysenteriae. Antimicrobial susceptibilities were evaluated by disc diffusion method and the highest resistance rates were found against trimethoprim/sulfamethoxazole (91.6%), followed by tetracycline (68.3%) and ampicillin (26.6%). Resistance against ampicillin, chloramphenicol and amoxycillin/clavulanic acid were found higher in S.flexneri isolates than S.sonnei (p< 0.001). All isolates were found to be susceptible to ciprofloxacin, gentamicin and ceftazidime. S.sonnei demonstrated 12 and S.flexneri demonstrated 4 antibiotic resistance models. All isolates were carrying plasmids with varying sizes and varying numbers between 1 to 7. S.sonnei isolates demonstrated 27 and S.flexneri isolates demonstrated 8 plasmid profiles. S.sonnei isolates were clustered in 4 patterns and S.flexneri were clustered in 5 patterns by PFGE. This method demonstrated obvious clonal similarity among S.sonnei strains isolated in Ankara and discriminative power (DP) was calculated as 0.26. PPA and ART demonstrated higher DP among S.sonnei strains (0.97 and 0.75, respectively). In this study gain or loss of instable genetic mobile elements were thought to be responsible for higher discriminative powers of PPA and ART methods. These typing methods were found to be appropriate for the epidemiological investigation of strains collected in a short time period. PFGE was found to be convenient for the evaluation of clonal relatedness of the strains, however, in such geographical areas where the same clone was in circulation, use of ART and/or PPA together with PFGE would be useful for precise discrimination of Shigella strains.

Urinary tract infections (UTIs) caused by extended-spectrum beta lactamase (ESBL)-producing bacteria have become a growing problem worldwide. The aim of this study was to investigate the clinical and radiological findings in patients with community-acquired UTIs owing to ESBL-producing bacteria. Files of the patients that had UTI owing to ESBL-producing bacteria, between January 2008 and December 2009, were retrospectively evaluated. One hundred and eleven UTI episodes in 94 patients were included. Seventy-five per cent of the patients had recurrent UTIs. Ultrasound, dimercaptosuccinic acid (DMSA) scintigraphy and voiding cystourethrography (VCUG) were found abnormal in 36%, 46% and 31% of the patients, respectively. Overall, 68% of the patients had ≥1 underlying predisposing factor for UTI. Male patients and acute pyelonephritis (APN) episodes were more frequent at small ages. The rate of female patients and cystitis episodes predominated with increasing age. Ultrasound, DMSA scintigraphy, VSUG and UT abnormalities were more frequent in patients with APN, and lower UT disturbances were more frequent in patients with cystitis. UTIs owing to ESBL-producing bacteria begin to replace UTIs owing to non-ESBL-producing bacteria. However, the clinical pattern of these infections does not seem to be different. Thus, our aim should be to correct underlying predisposing factors in general in order to prevent infections owing to ESBL-producing bacteria.