Occurrence of OXA-48 and NDM-1 carbapenemase-producing Klebsiella pneumoniae in a Moroccan university hospital in Casablanca, Morocco.

The purpose of this investigation was to determine the prevalence and the characteristics of carbapenemase-producing Klebsiellapneumoniae isolates recovered from various clinical specimens in the university hospital of Casablanca, in Morocco. We conducted a prospective study on a total of 166 K. pneumoniae isolates collected from June to August 2011. The strains suspected to carry carbapenemase showed reduced susceptibility to imipenem or ertapenem. The PCR and a sequencing strategy were used to identify carbapenemases, expended spectrum β-lactamases (ESBL), plasmid-mediated AmpC β-lactamases, plasmid mediated quinolone resistance and aminoglycoside resistance determinants. The clonal relationships between isolates were analyzed by pulsed field gel electrophoresis (PFGE). Among the 166 K. pneumoniae isolates studied, 11 (6%) were carbapenemases producers, 9 of which harbored blaOXA-48 and 2 were positive for blaNDM-1. All carbapenemase-producing K. pneumoniae were also ESBL producers and the blaCTX-M-15 was the most frequent ESBL gene detected (n=9), blaCTX-M-28 and blaSHV-28 were also encountered in one isolate each. The K.pneumoniae isolates carried also non-ESBL genes blaTEM-1 (n=9), blaSHV-1 (n=8) and blaOXA-1 (n=3). Five isolates harbored qnr genes, qnrS1 (n=3) and qnrB1 (n=2) variants. Six isolates were positive for aac(6')-Ib-cr gene and two for aac(3)-II gene. The class 1 integron was detected in five isolates. PFGE has revealed the presence of a clonal dissemination in our hospital. The results of conjugation experiments indicated that blaOXA-48+blaCTX-M-15, blaOXA-48+blaCTX-M-28, blaNDM-1+blaCTX-M-15+blaTEM-1+blaOXA-1+qnrS1+aac(6')-Ib-cr and blaNDM-1+blaCTX-M-15+blaTEM-1+qnrB1+aac(6')-Ib-cr genes were co-transferred and that these genes were carried by a conjugative plasmid of high molecular weight.

Barguigua A ，Zerouali K ，Katfy K ，El Otmani F ，Timinouni M ，Elmdaghri N ... -  《-》

Prevalence and types of extended spectrum β-lactamases among urinary Escherichia coli isolates in Moroccan community.

This study was designed to characterize extended-spectrum-β-lactamases (ESBL) produced by Escherichia coli isolates causing community urinary tract infections over a 2-year period (2010 and 2011) in a Moroccan large geographical region. Molecular characterization was done by using PCR and sequencing of the β-lactamases genes and plasmid-mediated quinolone resistance determinants. Among 1174 isolates, 49 (4.1%) were ESBL producers. The blaCTx-M-15 (n = 31) was the most frequent ESBL gene detected, followed by blaCTx-M-1 (n = 5), blaSHV-12 (n = 6), blaPER-2 (n = 3), then blaTEM-3, blaTEM-20, blaTEM-158, blaSHV-27, blaSHV-28, blaSHV-36, blaSHV-125, blaCTx-M-14 and blaCTx-M-27 with one isolate for each. The non-ESBL genes detected were blaTEM-70 (n = 1), blaTEM-176 (n = 1), blaTEM-104 (n = 6), blaTEM-1 (n = 15) and blaOxA-1 (n = 12). Plasmid mediated AmpC β-lactamases genes; blaACT-5 (n = 1), blaDHA-1(n = 2) and blaCMY-2 (n = 4) were detected in seven isolates (14.2%). The blaOxA-48 (n = 1) and blaIMP-1 (n = 1) carbapenemases genes were detected among five carbapenem-resistant E. coli. Five isolates (10.2%) harboured qnr genes, qnrB1 (n = 3), qnrB2 (n = 1) and qnrS1 (n = 1) type were detected. Thirty isolates (61.2%) were positive for aac(6')-Ib-cr gene. The class 1 integron was detected in twenty two (44.8%) isolates. Phylogenetic grouping revealed that 22 (44.8%) isolates belonged to group A, while 15 (30.6%), 11 (22.4%) and 1 (2%) belonged to B2, D and B1. Results of conjugation experiments indicated that blaCTx-M-15, blaTEM-1, blaOxA-1, aac(6')-Ib-cr and qnrB1 genes were co-transferred and that these genes were carried by a conjugative plasmid of high molecular weight. The results of this work reports the genetic diversity of ESBL genes, with the CTX-M-15 enzyme being the most common among ESBL-producing E. coli in Moroccan community.

Barguigua A ，El Otmani F ，Talmi M ，Zerouali K ，Timinouni M ... -  《-》

The emergence of OXA-48- and NDM-1-positive Klebsiella pneumoniae in Riyadh, Saudi Arabia.

To investigate the emergence of NDM-, OXA-48-, and VIM-producing Klebsiella pneumoniae in Saudi Arabia. From June to December 2011, we obtained K. pneumoniae isolates with reduced sensitivity to carbapenem identified in Riyadh, Saudi Arabia. Only non-duplicate clinical and surveillance isolates obtained from inpatients were included. PCR amplification was carried out for the detection of extended-spectrum beta-lactamase genes (blaCTX-M, blaTEM, blaSHV) and carbapenemase genes (blaKPC, blaVIM, blaIMP, blaNDM, and blaOXA-48). Susceptibility to imipenem, meropenem, amikacin, gentamicin, trimethoprim-sulfamethoxazole, and colistin was determined. Of the 60K. pneumoniae isolates studied, 45 were from patients in the intensive care unit. Forty-seven isolates harbored blaOXA-48, 12 were positive for blaNDM, and one for blaVIM. No isolate harbored a combination of these resistance genes. No isolate harbored blaKPC or blaIMP. All 37 blaCTX-M-positive isolates belonged to CTX-M group 1, and 29 were positive for a combination of blaCTX-M and blaOXA-48. blaTEM and blaSHV genes were found in 17 and 39 isolates, respectively. All isolates were imipenem- and meropenem-resistant, with a high rate of co-resistance to the other antibiotics. Three blaOXA-48-positive isolates with colistin resistance were detected. Multidrug-resistant K. pneumoniae isolates harboring blaOXA-48, blaNDM, and colistin resistance are emerging in Saudi Arabia.

Shibl A ，Al-Agamy M ，Memish Z ，Senok A ，Khader SA ，Assiri A ... -  《-》

Characterization of extended-spectrum beta-lactamase, carbapenemase, and plasmid quinolone determinants in Klebsiella pneumoniae isolates carrying distinct types of 16S rRNA methylase genes, and their association with mobile genetic elements.

Wei DD ，Wan LG ，Yu Y ，Xu QF ，Deng Q ，Cao XW ，Liu Y ... -  《-》

Molecular characterization of NDM-1-producing Klebsiella pneumoniae ST29, ST347, ST1224, and ST2558 causing sepsis in neonates in a tertiary care hospital of North-East India.

Geographical differences can manifest in different spectra of microorganisms and patterns of antibiotic resistance. Considering this, Enterobacteriacae isolated from septicemic neonates from a tertiary care centre in Agartala, India were studied with focus on carbapenem resistance. Two hundred non-duplicate Enterobacteriaceae, of which 12 NDM-1-producing Klebsiella pneumoniae were recovered. Antibiotic susceptibility tests and detection of ESBLs and carbapenemases were performed for all Enterobacteriaceae. For NDM-1-producing isolates, plasmid-mediated quinolone resistance genes, addiction systems, genetic environment of blaNDM-1 and virulence genes was investigated by PCR. Bacterial clonal relatedness was established using REP-PCR, PFGE, and multi-locus sequence typing (MLST). Transferability of blaNDM-1 was tested by conjugation and transconjugants were characterized. K. pneumoniae was the primary organism causing sepsis in neonates. Resistance to different antimicrobials was high except for aminoglycosides and carbapenems. blaCTX-M was present in all isolates. All carbapenem-resistant isolates harboured blaNDM-1 as the only carbapenemase. blaCTX-M-15 and qnrS1 were detected in all NDM-1-producing isolates. Plasmid analysis of transconjugants revealed that blaNDM-1 along with blaCTX-M-15, qnrS1, qnrB1, aac(6')-Ib, aac(6')-Ib-cr and ccdAB or vagCD addiction systems were carried on large IncFIIK conjugative plasmids of varied sizes. blaNDM-1 was associated with ISAba125 or ISEc33 element at its 5'-end. In addition, isolates also harboured wabG, uge, fimH, mrkD, and entB virulence genes. The NDM-1-producing K. pneumoniae belonged to four distinct clones and were distributed in 4 STs (ST347, ST29, ST2558, and ST1224), of which ST347 was predominant. The association of blaNDM-1 with diverse STs in K. pneumoniae from neonates indicates the promiscuity of the gene and its widespread dissemination.

Mukherjee S ，Bhattacharjee A ，Naha S ，Majumdar T ，Debbarma SK ，Kaur H ，Dutta S ，Basu S ... -  《-》