beta-Lactamases have been identified as the major cause of antimicrobial resistance to beta-lactam antibiotics in Escherichia coli. The activities of ampicillin-sulbactam and amoxicillin-clavulanate as well as a range of beta-lactam antibiotics were studied with 87 clinical E. coli isolates from patients of the University Malaya Medical Center using the disc diffusion technique. Susceptible, intermediate and resistant categories were established based on the diameter of zones of inhibition set by the National Committee for Clinical Laboratory Standards (NCCLS). The isolates were then classified into 6 phenotypes according to the criteria stated in the methodology: S (susceptible to all beta-lactams); TL (resistant to aminopenicillins; amoxicillin-clavulanate susceptible and susceptible or intermediate to ampicillin-sulbactam); TI (resistant to aminopenicillins and ampicillin-sulbactam; susceptible to amoxicilin-clavulanate); TH-IRT (resistant to aminopenicillins; intermediate or resistant to amoxicillin-clavulanate; resistant to ampicillin-sulbactam); ESBL (resistant to aminopenicillins and oxyimino cephalosporins; positive results with the double-disc diffusion test); and CP (resistant to aminopenicillins, beta-lactam-beta-lactamase inhibitor combinations, oxyimino cephalosporins and cephamycins). Results showed that the TL phenotype was the commonest (40.2% of the isolates) followed by S (31%), TH-IRT (16.1%), ESBL and CP (3.4% each) and TI (2.3%). One isolate showed both ESBL and CP phenotypes while two isolates were classified as inconclusive. Representatives from each phenotype were further analysed for the presence of beta-lactamases which revealed a predominance of TEM and SHV enzyme producers. PCR-SSCP analysis of the SHV gene from all the ESBL and CP isolates revealed the predominance of SHV 5-type enzyme which was concurrent with our previous studies.
Phenotype ; Extended-spectrum beta lactamase ; sultamicillin ; Escherichia coli ; Ceruloplasmin

Klebsiella pneumoniae ranks high as a cause of adult pneumonia requiring hospitalization in Malaysia. To study whether extended-spectrum b-lactamase (ESBL) producing K. pneumoniae was linked to hospital outcomes, we retrospectively studied 441 cases of adult respiratory tract infections with microbial proven K. pneumoniae from an urban-based university teaching hospital between 2003 and 2004. 47 (10.6%) cases had ESBL. Requirement for ventilation and median length of hospital stay, were greater in ‘ESBL’ than in ‘non-ESBL’ group [34% vs. 7.4%, p<0.001; 14 days vs. 5 days, p<0.001 respectively] but not crude hospital mortality rate [21.3% vs. 12.4%, p=0.092]. There was a four-fold increased risk of requiring ventilation [4.61 (2.72-7.85)] when ESBL was present. Our findings support the association of ESBL producing K. pneumoniae with adversed hospital outcomes and reiterate the need for vigilance on the part of treating clinicians.
Extended-spectrum beta lactamase ; Hospitals ; Adult ; Respiratory ; lower case pea

Antimicrobial resistance to the extended-spectrum cephalosporins is increasingly reported worldwide. In the local setting, nosocomial infections with multi-resistant Gram-negative bacilli are not uncommon and are a growing concern. However, there is limited data on the carriage rates of such organisms in the local setting. In May 2001, a prospective study was carried out to determine the enteric carriage rates of ceftazidime-resistant Gram negative bacilli (CAZ-R GNB) among residents of nursing homes and from in-patients of the geriatric and adult haematology wards of University Malaya Medical Centre. Ceftazidime-resistant Gram-negative bacilli (CAZ-R GNB) were detected in 25 samples (30%), out of which 6 were from nursing home residents, 5 from geriatric in-patients and 14 from the haematology unit. A total of 28 CAZ-R GNB were isolated and Escherichia coli (10) and Klebsiella pneumoniae (7) were the predominant organisms. Resistance to ceftazidime in E. coli and Klebsiella was mediated by extended-spectrum beta-lactamases (ESBLs). Although the majority of the CAZ-R GNB were from patients in the haematology ward, the six nursing home residents with CAZ-R GNB were enteric carriers of ESBL-producing coliforms. Prior exposure to antibiotics was associated with carriage of ESBL organisms and to a lesser extent, the presence of urinary catheters.
seconds ; Upper case are ; Extended-spectrum beta lactamase ; Elderly ; Organisms (MeSH Category)