Genome sequence of multidrug-resistant Escherichia coli EC302/04, isolated from a human tracheal aspirate.

Escherichia coli is an important etiologic agent of lower respiratory tract infections (LRTI). Multidrug-resistant E. coli EC302/04 was isolated from a tracheal aspirate, and its genome sequence is expected to provide insights into antimicrobial resistance as well as adaptive and virulence mechanisms of E. coli involved in LRTI.

Prevalence and characterization of multidrug-resistant and extended-spectrum beta-lactamase-producing Escherichia coli from pediatric wards of a Malaysian hospital.

The emergence of Escherichia coli resistant to extended-spectrum cephalosporins (ESCs) is of concern as ESC is often used to treat infections by Gram-negative bacteria. One-hundred and ten E. coli strains isolated in 2009-2010 from children warded in a Malaysian tertiary hospital were analyzed for their antibiograms, carriage of extended-spectrum beta-lactamase (ESBL) and AmpC genes, possible inclusion of the beta-lactamase genes on an integron platform, and their genetic relatedness. All E. coli strains were sensitive to carbapenems. About 46% of strains were multidrug resistant (MDR; i.e., resistant to ≥3 antibiotic classes) and almost half (45%) were nonsusceptible to ESCs. Among the MDR strains, high resistance rates were observed for ampicillin (98%), tetracycline (75%), and trimethoprim/sulfamethoxazole (73%). Out of 110 strains, bla(TEM-1) (49.1%), bla(CTX-M) (11.8%), and bla(CMY-2) (6.4%) were detected. Twenty-one strains were ESBL producers. CTX-M-15 was the predominant CTX-M variant found and this is the first report of a CTX-M-27-producing E. coli strain from Malaysia. Majority (3.1%) of the strains harbored class 1 integron-encoded integrases with a predominance of aadA and dfr genes within the integron variable region. No gene cassette encoding ESBL genes was found and integrons were not significantly associated with ESBL or non-ESBL producers. Possible clonal expansion was observed for few CTX-M-15-positive strains but the O25-ST131 E. coli clone known to harbor CTX-M-15 was not detected while CMY-2-positive strains were genetically diverse.

Genetic fingerprinting and antimicrobial susceptibility profiles of Pseudomonas aeruginosa hospital isolates in Malaysia.

BACKGROUND AND PURPOSE: Pseudomonas aeruginosa is the third most common pathogen causing nosocomial infections. The objective of this study was to investigate the antimicrobial resistance profiles and genetic diversity of hospital isolates of P. aeruginosa and to investigate the presence of several resistance genes and integrons. METHODS: In this retrospective study, 48 clinical isolates of P. aeruginosa from 6 public hospitals in Malaysia were analyzed by antimicrobial susceptibility test and DNA fingerprinting techniques. RESULTS: Most of the P. aeruginosa isolates were resistant to tetracycline (73%) and chloramphenicol (60%) and, to a lesser extent, cefotaxime (40%), ceftriaxone (31%), cefoperazone (29%), ticarcillin (25%), piperacillin (23%), and imipenem (21%). Less than 20% of the isolates were resistant to ceftazidime, gentamicin, cefepime, ciprofloxacin, amikacin, piperacillin-tazobactam, and aztreonam (10%). Of the 48 isolates, 33 were multidrug resistant. Two isolates were extended-spectrum beta-lactamase (ESBL) producers using the double-disk synergy test. However, polymerase chain reaction (PCR) failed to detect any common ESBL-encoding genes in all isolates, except for bla(OXA-10) in PA7 that was found to be part of a class 1 integron-encoded aacA4-bla(IMP-9)-catB8-bla(OXA-10) gene cassette. Using PCR, class 1 integron-encoded integrases were detected in 19% of the P. aeruginosa isolates. Repetitive extragenic palindrome-PCR generated 40 different profiles (F = 0.50-1.0) and enterobacterial repetitive intergenic consensus-PCR produced 46 profiles (F = 0.51-1.0). Pulsed-field gel electrophoresis with SpeI-digested genomic DNA resulted in 45 different profiles (F = 0.50-1.00). CONCLUSIONS: Aztreonam appeared to be the most effective agent against multidrug-resistant P. aeruginosa isolates. Sixty nine percent of the P. aeruginosa isolates analyzed were multidrug resistant and the isolates were genetically diverse.

Characterization of multidrug-resistant and extended-spectrum beta-lactamase-producing Klebsiella pneumoniae strains from Malaysian hospitals.

The emergence of multidrug-resistant (MDR) and extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae poses a serious antibiotic management problem as resistance genes are easily transferred from one organism to another. Fifty-one strains of K. pneumoniae isolated from sporadic cases in various hospitals throughout Malaysia were analysed by antimicrobial susceptibility testing, PCR detection of ESBL-encoding genes and DNA fingerprinting. Although 27 of the 51 K. pneumoniae strains were MDR (i.e. resistant to three or more classes of antibiotics), the majority of the strains (98 %) were sensitive to imipenem. PCR detection using ESBL gene-specific primers showed that 46 of the K. pneumoniae strains harboured bla(SHV), 19 harboured bla(CTX-M), 5 harboured bla(OXA-1) and 4 harboured bla(TEM-1). Class 1 integron-encoded intI1 integrase was detected in 21 of the 51 K. pneumoniae strains and amplification of the integron 5'CS region showed the presence of several known antibiotic resistance gene cassettes of various sizes. Results of conjugation and transformation experiments indicated that some of the ESBL-encoding genes (i.e. bla(SHV), bla(CTX-M) and bla(TEM-1)) were transmissible and were likely plasmid-encoded. DNA fingerprinting using PFGE and PCR-based methods indicated that the 51 K. pneumoniae strains were genetically diverse and heterogeneous.