Description of novel resistance islands harbouring blaCTX-M-2 in IncC type 2 plasmids.

OBJECTIVES: We sequenced two IncA/C plasmids harbouring blaCTX-M-2 in Klebsiella pneumoniae clinical isolates and compared their antibiotic resistance islands. METHODS: Transconjugants were obtained from two clinical K. pneumoniae isolates harbouring blaCTX-M-2. Plasmid DNA from transconjugants underwent short-read whole-genome sequencing, reads were assembled, and gaps were closed by PCR and sequencing. Determination of plasmid replicons, antibiotic resistance genes, identification and characterisation of insertion sequence (IS) elements, and comparison with publicly available plasmid sequences were performed. RESULTS: blaCTX-M-2 was located in a complex class 1 integron In35::ISCR1::blaCTX-M-2, inserted in two different transposons designated Tn7057 and Tn7058, that reside in the resistance islands of plasmids pUR-KP0923 and pUR-KP1025, respectively. The general modules of both transposons were In35::ISCR1::blaCTX-M-2-Tn1000-like-Tn2*-ISKpn11-12-13 variable module-ΔTn21. In Tn7057 there was ΔIS10R-catA2 associated with an additional ISKpn13. Both plasmids belonged to IncC type 2 and ST3. pUR-KP0923 was 167 138 bp in length and had a 37 926-bp resistance island at position 4 (RI-4). Plasmid pUR-KP1025 was 168 128 bp with a RI-4 of 36 222 bp. CONCLUSION: This report describes the molecular nature of two transposons (Tn7057 and Tn7058) harbouring blaCTX-M-2 that reside in IncC type 2 ST3 plasmids. These transposons mediate resistance to oxyimino-cephalosporins, gentamicin and, in the case of Tn7057, chloramphenicol. CTX-M-2 is an important extended-spectrum ß-lactamase (ESBL) to South American epidemiology. It is remarkable that despite being only two plasmid sequences, the information revealed here could contribute to a better understanding of the resistance islands from IncC type 2 plasmids.

Terminal 13p deletion in squirrel monkey (Saimiri sciureus) with differentiated phenotype.

BACKGROUND: The taxonomic classification of squirrel monkeys is often controversial issue offering many different information. The classification of captive animals is difficult due to the phenotypic similarities between the presented species, which is observed mainly in coat coloration. METHODS: The objective of this study was to analyze the chromosome pattern of one squirrel monkey with off standard physical characteristics, which is kept in the Laboratory Animals Breeding Center in Rio de Janeiro State, Brazil, and try to establish some correlations. Chromosomes were obtained using lymphocyte culture technique. RESULTS AND CONCLUSIONS: Evaluation of G bands showed a terminal deletion in one chromosome of pair 13. The association of the results found with the different phenotypic characteristics led us to classify it as a Saimiri sciureus specimen with a structural chromosomal change, possibly allowing the expression of hemizygous alleles.

Allodemic distribution of plasmids co-harbouring blaCTX-M-15/aac(6')-Ib-cr/qnrB in Klebsiella pneumoniae is the main source of extended-spectrum ß-lactamases in Uruguay's paediatric hospital.

OBJECTIVES: This study aimed to describe the characteristics of clinical isolates of extended-spectrum ß-lactamase (ESBL)-producing enterobacteria (EPE) in Uruguay's paediatric hospital. METHODS: ESBLs, qnr alleles and aac(6')-Ib-cr were sought and characterised in EPE isolated between March 2010 and March 2012. Transfer of resistance determinants was assessed by conjugation. Incompatibility (Inc) groups, plasmid toxin-antitoxin systems (TAS) and plasmid size were determined in transconjugants. Clonality was analysed by pulsed-field gel electrophoresis. Multilocus sequence typing was done for ESBL-producing Klebsiella pneumoniae. RESULTS: A total of 77 EPE isolates were characterised, comprising 43% K. pneumoniae, 19.5% Serratia marcescens, 19.5% Escherichia coli, 17% Enterobacter cloacae and 1% Klebsiella oxytoca. ESBLs belonged mainly to the blaCTX-M family (69.6%) [blaCTX-M-15 (45%) and blaCTX-M-2 (31%)]. The aac(6')-Ib-cr/qnrB duplex was the most frequently detected plasmid-mediated quinolone resistance mechanism; this association was detected in K. pneumoniae harbouring blaCTX-M-15. Transconjugants were obtained for 71% of the EPE. Amongst transconjugants, certain combinations were found between ESBLs and Inc group, e.g. IncA/C-blaCTX-M-2, IncHI1/HI2-blaCTX-M-9 and IncHI1/HI2-blaSHV-12. In addition, the combination ccdAB-blaCTX-M-15 was also found. K. pneumoniae isolates harbouring blaCTX-M-15/aac(6')-Ib-cr/qnrB showed allodemic behaviour, with a predominance of ST14, ST45 and ST48. CONCLUSIONS: In this study, epidemiological changes in ESBL distribution could be explained by the spread of K. pneumoniae harbouring blaCTX-M-15/aac(6')-Ib-cr/qnrB, encoded mainly on conjugative plasmids featuring ccdAB TAS. Since reports of TAS in K. pneumoniae plasmids are scarce, new strategies are needed to combat intrinsic selection pressure exerted by the association, in conjugative plasmids, of resistance mechanisms with TAS.

First report of the ceftazidimase CTX-M-19 in South America.

We report the first detection of bla CTX-M-19 in South America, harboured in an Escherichia coli isolate obtained from a urine sample; such an isolate belonged to phylogenetic group A, ST603, and showed a ceftazidimase profile. bla CTX-M-19 was encoded in an approximately 100 kb IncI1/IncF conjugative plasmid, featuring pndAC and hok/sok addiction systems; the ß-lactamase gene was flanked upstream by three tandem-like transposons (IS26, IS10 and ISEcp1), inserted one inside the other, and downstream by IS903.

Association of broad-spectrum antibiotic use with faecal carriage of oxyiminocephalosporin-resistant enterobacteriaceae in an intensive care unit.

The link between administration of antibiotics and detection of third-generation-cephalosporin-resistant (TGCR) enterobacteriaceae in faeces was studied in patients in a burns intensive care unit (ICU). The presence of extended-spectrum beta-lactamase producers was also determined in these isolates. At least two rectal swab samples were taken from 43 of 72 patients admitted to the ICU from January 1998 to June 1999. Antibiotic resistance tests were performed for all isolated enterobacteriaceae using the methods of the National Committee for Clinical Laboratory Standards. Only 10 out of 30 antibiotic-treated patients showed TGCR enterobacteriaceae in faeces. Fisher's exact test showed a relationship between the administration of oxyiminocephalosporins (third-generation cephalosporins) (P=0.002) or carbapenems (P=0.003) and the isolation of TGCR enterobacteriaceae from faeces. The administration of oxyiminocephalosporins led to the selection of resistant strains in the faecal flora.

Schizophrenia and season of birth in a tropical region: relationship to rainfall.

Winter birth has been shown to increase the risk of schizophrenia in adult life. It has been hypothesized that this effect is due to seasonal variation in infectious diseases, including influenza, as exposure to influenza during mid gestation also increases the risk of schizophrenia. However, in many areas there is little variation in temperature during the year, although rainfall may vary greatly. We tested the hypothesis that, in a tropical region with wet and dry seasons, schizophrenia births would be related to rainfall. The data came from the city of Mossoro in north-eastern Brazil. In this area there is no meaningful variation in temperature, but there is a rainy season with little precipitation during the rest of the year. In this region, the prevalence of influenza parallels that of rainfall. There was a significant relationship between rainfall and the number of schizophrenia births three months later. In contrast, there was no significant relationship between rainfall and general population births three months later. The relationship of birth to rainfall, rather than winter birth, may be associated with risk of schizophrenia in tropical regions; exposure to influenza during gestation may be the basis for such a relationship.