This study investigated the molecular epidemiology of Acinetobacter baumannii in the University of Debrecen in relation to antibiotic consumption. Overall and ward-specific antibiotic consumption was measured by the number of defined daily doses (DDD) per 100 bed-days between 2002 and 2012. Consumption was analysed against the number of A. baumannii positive patients per 100 bed-days, number of isolates per positive sample, and proportion of carbapenem resistant A. baumannii, using time-series analysis. Altogether 160 A. baumannii isolates from different wards were collected and analysed. Carbapenemase genes bla OXA-23-like , bla OXA-24-like , bla OXA-48-like , bla OXA-51-like , bla OXA-58-like and integrons were sought by PCR. Relatedness of isolates was assessed by PFGE. Prevalence and carbapenem resistance of A. baumannii were statistically associated with carbapenem consumption. Prevalence data followed carbapenem usage with three quarterly lags (r50.51-0.53, P,0.001), and meropenem and ertapenem, but not imipenem usage, affected prevalence. Colistin usage, in turn, lagged behind prevalence with one lag (r50.68-0.70, P,0.001). Six clusters were identified; the neurology ward with the lowest carbapenem consumption was associated with the carbapenem-susceptible cluster, as well as with the carbapenem-susceptible isolates in the cluster with variable susceptibility. Wards with high carbapenem usage almost exclusively harboured isolates from carbapenem-resistant clusters. All clusters were dominated by isolates of one or two wards, but most wards were represented in multiple clusters. Increases in prevalence and carbapenem resistance of A. baumannii were associated with usage of meropenem and ertapenem but not of imipenem, which led to the spread of multiple clones in the University.

Aims: We compared the prevalence of extended-spectrum beta-lactamase (ESBL) producers in the faecal samples of 1,109 healthy individuals screened for employment purposes and in 531 asymptomatic individuals applying for long-term care (LTC). Methods: Eosin-methylene blue agar plates supplemented with 2 mg/l cefotaxime were used to determine which individuals were ESBL producers. ESBL phenotype was confirmed by double-disk synergy test and ESBL genes were identified by sequencing. ESBL producers were characterized by co-resistance and integron carriage. Results: ESBL producers were more frequent in the LTC applicants than in the employment screening individuals (7.2 vs. 2.0%; p < 0.0001), with 43 Escherichia coli, 18 Klebsiella pneumoniae, 1 Klebsiella oxytoca and 1 Proteus mirabilis being found. In the employment screening individuals, only E. coli was found. Most ESBL genes (79.4%, 50/63) were bla_CTX-M type; bla_CTX-M-15 was more frequent in the LTC applicants (p < 0.001). Regarding ESBL genes and integron diversity, E. coli isolates from the LTC applicants were more similar to K. pneumoniae than to E. coli from the employment screening individuals. Conclusion: These differences in the characteristics of ESBL producers may represent different sources of colonization. Most LTC applicants harboured K. pneumoniae or E. coli that were probably hospital-acquired whereas the E. coli isolates of many healthy individuals showed similarities to environmental E. coli.

Because asymptomatic carriage of extended-spectrum beta-lactamase (ESBL) producers is a risk factor for infection, data on colonization dynamics are important when planning infection control. This study investigated fecal colonization with ESBL producers among inpatients, outpatients and medical students and compares the characteristics of ESBL producers among these groups. Carriage rates were investigated in 5581 fecal samples; 4343 from inpatients (330, 1397, 619 and 1864 from adult ICUs [intensive care units], adult non-ICUs, pediatric ICUs and pediatric non-ICUs, respectively), 814 from outpatients and 424 from screening of medical students. ESBL producers were characterized by co-resistance, integrons carried, and aminoglycoside resistance and ESBL genes. Dynamic regression models were built to identify relationships between combinations of time series of monthly antibiotic consumption, prevalence of carriers and infected subjects. Inpatients, ICU patients and adults showed higher prevalence than outpatients, non-ICU patients or children (7.4%, 9.3% and 12.0% vs. 3.1%, 6.1% and 4.1%, respectively). Klebsiella pneumoniae was more frequent in ICU patients; dominance of CTX-M-15 producers was more marked in adult than in pediatric inpatients. ESBL carriage was shown to be a consequence of infection in adults in the time-series analysis; antibiotic consumption had little effect. The epidemiology of colonization with ESBL producers differed between pediatric ICU, adult ICU and adult non-ICU patients. In adults, carriage of ESBL producers seems to be the consequence of infection, especially in ICU patients; the main source of colonization is nosocomial acquisition. In contrast, children are less likely to acquire colonizer strains in hospitals; importation of ESBL producers by colonized children seems to be significant.

26Background: Faecal carriage of extended-spectrum beta-lactamase (ESBL) producing Enterobacteriaceae 27 in healthy individuals was examined and compared to previous results obtained in such individuals a few 28 years earlier. 29Methods: Faecal samples from 779 individuals screened for employment purposes and from 225 30 applicants to long-term care (LTC) were screened between November 2013 and May 2014. 31Results: The overall rate of fecal carriage was 3.0% (30/1004). The carriage rate was significantly higher 32 in applicants for LTC (5.3% vs. 2.3%; p=0.019). All isolates carried CTX-M ESBLs, with an 33 overwhelming dominance of bla (84.4%) in both groups and in both E. coli and Klebsiella 34 pneumoniae. 35Conclusions: The prevalences were comparable to those in the earlier study, but a marked decrease of the 36 diversity of ESBL genes in E. coli from the employment screening group was found, suggesting that the 37 ESBL-producing isolates originating from diverse sources are being replaced by highly successful bla CTX- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 To screen for ESBL production, faecal samples were inoculated onto eosin methylene blue agar plates 60 supplemented with 2 mg/l cefotaxime. Confirmation of ESBL phenotype was performed using double 61 disk synergy test (Oxoid, Basingstoke, UK). The isolates were identified by MALDI Biotyper (Bruker, 62Bremen, Germany) and by species-specific PCRs. Susceptibility to ertapenem, meropenem, imipenem, 63 cefotaxime, ceftazidime, cefepime, ciprofloxacin, co-trimoxazole, colistin, amikacin, gentamicin and 64 tobramycin was tested by disk diffusion according to EUCAST recommendations. All isolates were 65 screened for the genes bla TEM , bla SHV , and bla CTX-M , amplified genes were sequenced. Five 66 aminoglycoside resistance genes aac(3')-IIa, aac(6')-Ib, aph(3')-Ia, ant(2")-Ia, ant(3")-Ia, and class 1 67 and 2 integrons were sought for by PCRs. Gene cassette arrays were determined by sequencing. For 68 Escherichia coli phylogenetic group and the clone O25b-ST131 were determined by PCRs. All technical 69 protocols were described in our earlier publication [5] Resistance to other antibiotic classes than beta-lactamases was common. Eleven, twelve, eight and 13 of 84 14 isolates were resistant to ciprofloxacin, co-trimoxazole, gentamicin and amikacin, respectively, in the 85 LTC group, while these numbers were eleven, eleven, six and six of 18 isolates in healthy individuals. 86This difference in susceptibility to amikacin was also evident when comparing only E. coli isolates. 87Integron carriage rates were comparable. In the LTC group class 1 integrons were detected in four K. 0/18, p=0.02, respectively). This applied when comparing only E. coli isolates from the two groups (5/7 96 vs. 2/18, p=0.007 and 3/7 vs. 0/18, p=0.015, respectively). Phylogroup distributions wer...

Pseudomonas aeruginosa isolates from a 5-bed intensive care unit were fingerprinted with 26 pulsed-field gel electrophoresis and tested for aminoglycoside resistance genes aac(6′)-Ib, aac(3″)-IIa, ant(2″)-27 Ia, armA, rmtA, and rmtB and integrons and virulence genes/operons phzI, phzII, phzM, phzS, apr, lasB, plcH, plcN, 28 pilA, algD, toxA, exoS, exoT, exoY, and exoU. Two major clusters were identified (49 and 19 isolates), harbouring 29 aac(6′)-Ib, bla PSE-1 , and ant(3″)-Ia genes or ant(2″)-Ia gene, respectively, on a class I integron. Most virulence 30 genes except for exoU and pilA were found. Only 1 isolate of the minor cluster (8 isolates) and 1 of the 22 31 sporadic isolates carried integrons (without gene cassettes); virulence profile was highly variable. Comparing 32 the resistance and virulence patterns of endemic and sporadic isolates suggests that integron-borne 33 aminoglycoside resistance is more closely associated with the frequency than virulence. Consequently, 34 aminoglycoside usage may have played a role in maintenance of the endemic clones.35