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Biomedical subjects

G Kumarasinghe

Publications and source records attributed to G Kumarasinghe.

At least 37 records · Page 2Linked to original sources
PubMed1995

Antimicrobial resistance problem in a university hospital.

In a study conducted in 1991 in the National University Hospital, Singapore, the susceptibilities of a total of 2156 recent clinical isolates were tested against 25 antimicrobial drugs. The organisms were those isolated from routine specimens received in the microbiology laboratory. About 40% Staphylococcus aureus isolations in the hospital were resistant to methicillin. A high incidence of the resistance was noted among Staphylococcus aureus and coagulase negative staphylococci to antistaphylococcal drugs. Acinetobacter sp. and Klebsiella sp. are becoming major threats with regard to antimicrobial treatment as they are multi-drug resistant. Pseudomonas aeruginosa did not show a resistance problem except to pefloxacin (74%). Ampicillin resistance of Acinetobacter sp. (93%) was reduced to 71% by ampicillin/clavulanic acid and to 7% by ampicillin/sulbactam. With regards to the urinary isolates higher rates of resistance were noticed with Pseudomonas aeruginosa to antipseudomonas drugs and for co-trimoxazole with other Gram negative organisms, compared to non-urinary isolates.

Acinetobacter↗
PubMed1995

Detection of Mycobacterium tuberculosis in sputum, pleural and bronchoalveolar lavage fluid using DNA amplification of the MPB 64 protein coding gene and IS6110 insertion element.

Two gene sequences specific for Mycobacterium tuberculosis were evaluated for the diagnosis of pulmonary tuberculous (PTB) in pleural fluid (PF), bronchoalveolar lavage fluid (BAL) and sputum (Sp). The 240 bp sequence (nts 460-700) coding for the MPB 64 protein coding gene and the 123 bp IS6110 insertion element present in multiple copies in the mycobacterial genome were amplified using the polymerase chain reaction. Fifty-nine clinical specimens were studied. The diagnosis of PTB was confirmed by positive M. tuberculosis cultures in 14 specimens, and by the presence of characteristic histological features of granuloma and Langerhan's giant cells on pleural biopsy in 3 PF specimens through cultures for M. tuberculosis were negative. The remaining 42 specimens were obtained from patient's with non-tuberculosis pulmonary infections or malignancy, and these served as negative controls. Our results showed that the IS6110 insertion element and MPB 64 gene sequence were detected in all 14 culture positive PTB cases, although detection of the latter sequence required both DNA amplification and oligonucleotide hybridization. There was however one false positive specimen with the MPB 64 detection protocol. More importantly, both the MPB 64 sequence and IS6110 insertion element protocols were unable to detect M. tuberculosis DNA in the 3 PF samples diagnosed by histological characteristics on pleural biopsy and culture negative. We conclude that DNA amplification for M. tuberculosis-specific sequences is a useful method for rapid diagnosis of PTB in culture positive specimens. However, the false negative results with TB culture negative cases of tuberculosis pleurisy, limits its usefulness for the diagnosis of tuberculous pleurisy.

Base Sequence↗
PubMed1995

Hospital acquired infections in a Singapore Hospital: 1985-1992.

A prospective survey of hospital-acquired infections (HAI) was conducted from 1985 to 1992. The survey used laboratory results to estimate incidence and alert infection control staff to a need for further action. The results were analysed with regard to the site, speciality and type of organism. The distribution by speciality of patients who had methicillin resistant Staphylococcus aureus infections was compared with the distribution of all patients with HAI. Although the surveillance was only partial, the data collected from year to year over the period of study seemed constant. The distribution of infection by type, location and bacterial cause was similar to results from other parts of the world. Notable differences were the high incidence of Acinetobacter sp., and the pattern of antimicrobial susceptibility to commonly used agents. Over half the Staphylococcus aureus isolates were methicillin resistant.

Bacteremia↗
PubMed1995

Genital Group B Streptococcus carriage in the antenatal period: its role in prom and preterm labour.

Of 326 high vaginal swabs taken during the antenatal period, Group B Streptococcus (GBS) was isolated from the birth canal in 46 women, giving a carrier rate of 14.1%, which is within the often quoted range of between 5% - 25% in different parts of the world. Carriage rates were similar at different gestations. In a subgroup of 34 women, 2 swabs taken at least 5 weeks apart yielded results which were discordant in over one fifth of the time. This knowledge of the natural history of GBS carriage questions the practice of treating asymptomatic carriers of GBS in the antenatal period to prevent transmission of GBS to the neonate. The group of women with positive swabs in the antenatal period did not have a significantly higher incidence of preterm labour and/or prelabour rupture of membranes (PROM) compared with the group of women with negative swabs. Routine screening of the antenatal population for GBS carrier status prior to 32 weeks gestation may not identify women at high risk of PROM or preterm labour.

Adult↗
PubMed1994

Antimicrobial susceptibilities of clinical isolates of Acinetobacter baumannii from Singapore.

The in vitro activities of 17 antimicrobial agents alone or in combination against 70 clinical isolates of Acinetobacter baumannii from Singapore were determined by broth microdilution. The MICs of amoxicillin, ampicillin, ceftazidime, ceftriaxone, gentamicin, and piperacillin for 90% of the strains were > or = 128 micrograms/ml. Addition of sulbactam to ampicillin produced improved activity, whereas adding tazobactam to piperacillin did not. The MICs of amikacin, ciprofloxacin, and imipenem for 90% of the strains were 32, 32, and 16 micrograms/ml, respectively.

Acinetobacter↗
PubMed1994

Multiple antibiotic resistance in Klebsiella spp. and other Enterobacteriaceae isolated in Singapore.

A common pattern of multiple antibiotic resistance has been noted in bacteria isolated from Singaporean patients. The resistance pattern includes: ampicillin, cefuroxime, ceftazidime and other third generation cephalosporins, aztreonam, gentamicin and other aminoglycosides. The bacterial species implicated are Klebsiellas and other members of the Enterobacteriaceae. Preliminary laboratory investigation with a disk-diffusion augmentation test suggests the presence of extended-spectrum beta-lactamases. A retrospective study of laboratory blood culture records shows a rising incidence of resistance in Klebsiella spp. since 1985. Antimicrobial susceptibility results suggest a high degree of co-transfer of aminoglycoside resistance. The high frequency of this type of multiple antibiotic resistance should result in greater caution in the selection of presumptive antibiotic therapy for septicaemia, in order to avoid treatment failure and further selection of resistant strains.

Anti-Bacterial Agents↗
PubMed1994

Increasing prevalence of antimicrobial resistance among organisms isolated from blood culture in a Singapore hospital.

The blood culture isolates obtained over the period 1985-1990 in a general teaching hospital were reviewed to determine trends in the prevalence of resistance to antimicrobial drugs. The percentages of Staphylococcus aureus isolates resistant to methicillin increased each year. Resistance among coagulase negative staphylococci also increased in prevalence: by 1990 approximately 50% of such isolates were resistant to methicillin, erythromycin, co-trimoxazole and gentamicin, 24% were resistant to clindamycin, 20% to fucidic acid but only 0.5% to vancomycin. Isolates of Enterobacteriaceae, excluding community-acquired salmonellae, showed increasing prevalence of resistance to beta-lactams, as did Acinetobacter spp isolates to gentamicin, co-trimoxazole and ceftriaxone. The isolates of Pseudomonas aeruginosa were exceptional, having no evident increase in the prevalence of resistance during the period. The rapid increases observed in relation to the other pathogens indicate the need for an antibiotic policy based on continuous surveillance of susceptibility patterns in the hospital.

Anti-Bacterial Agents↗
PubMed1993

Nosocomial urinary tract infection: a microbiological study.

Nosocomial urinary tract infection (UTI) is an important cause of increased morbidity and mortality in hospitalised patients. The increasing use of broad spectrum antibiotics will result in changes in the microbiological and antibiotic sensitivity pattern of pathogens isolated from nosocomial UTI. We have endeavoured to study the bacteriological pattern of nosocomial UTI and the antibiotic sensitivity patterns of the pathogens concerned. Over a period of one year, a total of 541 patients with 656 episodes of nosocomial UTI were studied. A total of 748 organisms were isolated. The two main complicating factors in nosocomial UTI were urogenital instrumentation (70.4%) and diabetes mellitus (24.2%). Klebsiella species (spp) was the predominant organism isolated (25.0%) and was significantly associated with age and diabetes mellitus. Klebsiella spp in nosocomial UTI showed an overall increase in resistance to antibiotics and multiple antibiotic resistant strains were not uncommon. Escherichia coli was isolated in 17.7% of cases. Streptococcus faecalis was isolated in 10.6% of cases and was significantly associated with instrumentation. Pseudomonas spp was isolated in 8.6% of cases and was generally sensitive to ceftazidime and amikacin. It was associated with systemic malignancies and the use of immunosuppressants.

Adolescent↗
PubMed1993

Moraxella catarrhalis respiratory infection in adults.

Moraxella catarrhalis (MC) is an upper respiratory tract commensal which may also be pathogenic. In this report we examined the clinical features, microbiology and therapeutic response in 30 consecutive adult patients with pneumonia who had MC isolated in the sputum. The mean age was 66 years with an equal sex ratio. Most patients gave a history of cigarette smoking (77%) and had underlying pulmonary diseases (73%). Dyspnea and productive cough were the most common complaints (87%). Fever was a manifestation in 60% of patients. Chest X-ray features of pneumonia were noted in 78% of patients while leucocytosis (> 11,000/mm3) was evident in 70%. While all isolates were susceptible to tetracycline, 70% were resistant to penicillin/ampicillin by in-vitro testing. Three patients died, two from their underlying illnesses and one from myocardial infarct. We believe that MC isolated in sputum cultures from symptomatic adults with underlying respiratory diseases should be treated as a pathogen. The short term prognosis is good.

Adult↗
PubMed1993

Prospective study of the aetiology of adult community acquired bacterial pneumonia needing hospitalisation in Singapore.

A prospective survey of 96 consecutive adult patients with community acquired pneumonia requiring hospitalisation was carried out at National University Hospital, Singapore. Causative pathogens were identified in 58% of patients. Mycobacterium tuberculosis was the most common pathogen (21%), followed by Streptococcus pneumoniae (12%), Haemophilus influenzae (5.2%), Mycoplasma pneumoniae (5.2%) and Staphylococcus aureus (4.2%). Gram-negative organisms (apart from Haemophilus influenzae) were found in 10% of pneumonia patients. More than half of the patients had pre-existing illness, the most common was diabetes mellitus (21%).

Adolescent↗
PubMed1992

Urinary tract infections in patients with diabetes mellitus.

We have endeavoured to determine whether there is any difference in the bacteriological pattern of UTI and the antibiotic sensitivity patterns of the pathogens concerned between diabetic and non-diabetic patients. Over a period of 1 year, a total of 287 diabetic patients (221 females and 66 males) with community-acquired and nosocomial urinary tract infections were studied. There were 265 patients (228 females and 37 males) without any predisposition to urinary tract infections (UTI) and who served as controls. Although Escherichia coli was the predominant organism in community-acquired UTI in diabetic patients, it was found significantly less than in the non-diabetic population (P less than 0.005). The percentage of Klebsiella species causing community-acquired UTI in diabetic patients was significantly higher than in non-diabetics (P less than 0.005). The antibiotic sensitivity patterns of the organisms in the two groups, however, were not significantly different. The organisms isolated from nosocomial UTI in diabetics showed a significantly greater preponderance of Klebsiella spp. and a significantly lower percentage of E. coli when compared to community-acquired UTI in diabetics (P less than 0.005). Klebsiella spp. in nosocomial UTI of diabetics showed an overall increase in resistance to antibiotics. At least a quarter of the isolates of Klebsiella spp. in nosocomial UTI were resistant to third-generation cephalosporins. Patients with diabetes mellitus appear to have an increased incidence of Klebsiella spp. as the pathogen in both community-acquired and nosocomial UTI. Antibiotic resistance in the organisms isolated from nosocomial UTI is greater than that related to community-acquired UTI in diabetic patients.

Aged↗
PubMed1992

A study of 245 infected surgical wounds in Singapore.

The aims of the study were to correlate the laboratory detection rate of wound infections with the actual wound infection rate, and to analyse the bacteriology of these wounds to provide a rationale for antibiotic usage in prophylaxis and treatment of surgical wound infections. The wound infection rate in a general surgical unit was determined using the most comprehensive surveillance available to us and was correlated with the laboratory detection rate. A correlation coefficient of 0.8 was obtained, allowing a reasonable estimation of the actual wound infection rate from laboratory data. Review of the bacteriology of consecutive infected surgical wounds over a 4 year period in a university hospital, revealed that the commonest organisms cultured were Staphylococcus aureus, Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, enterococci and beta-haemolytic streptococci. Methicillin-resistant S. aureus (MRSA) caused 50% of all staphylococcal wound infections. All MRSA isolates were sensitive to fusidic acid and vancomycin. All the non-MRSA isolates of S. aureus were sensitive to cephalexin. Some 89% of E. coli were sensitive to gentamicin, with 93% and 100% sensitive to cefuroxime and ceftriaxone respectively. Klebsiella isolates have shown an increased resistance to aminoglycosides, with a new strain from one patient, isolated in 1990, resistant to penicillins, aminoglycosides and third generation cephalosporins. Pseudomonas spp., enterococci and beta-haemolytic streptococci did not show a change in resistance patterns over the same time period.

Anti-Bacterial Agents↗
PubMed1992

Antimicrobial resistance: patterns and trends in the National University Hospital, Singapore (1989-1991).

The commonly isolated organisms, Staphylococcus aureus, Escherichia coli, Klebsiella species, Pseudomonas aeruginosa, Acinetobacter species, Proteus species and Enterobacter species from clinical material other than blood, cerebrospinal fluid and stool, were analysed for their incidence and increasing trends of resistance to the commonly used antimicrobials. Staphylococcus aureus was tested against penicillin, methicillin, erythromycin, gentamicin and co-trimoxazole; Pseudomonas aeruginosa against amikacin, ceftazidime, gentamicin, piperacillin and cefsulodin; and gram negative bacilli against ampicillin, co-trimoxazole, cephalexin, cefuroxime, ceftriaxone, nalidixic acid and nitrofurantoin. Methicillin sensitive Staphylococcus aureus exhibited a high degree of resistance to penicillin only (83%), but methicillin resistant Staphylococcus aureus (34-46%) showed nearly 100% resistance to all drugs tested except for co-trimoxazole over the period of study. A high incidence of resistance was found among Klebsiella species, Enterobacter species, Acinetobacter species and Pseudomonas species. Increasing trends of resistance against cephalosporins were noticed with respect to Acinetobacter species, Klebsiella species and Enterobacter species for cefuroxime and ceftriaxone; Pseudomonas aeruginosa for ceftazidime and cefsulodin. The overall resistance of organisms is notably high. Methicillin-resistant S. aureus is endemic and accounts for about 39% of all S. aureus isolates. The typical nosocomial organisms like Acinetobacter species and Klebsiella species are increasingly developing resistance to useful drugs such as gentamicin, cephalexin and ceftriaxone.

Cephalosporins↗
PubMed1992

Community acquired urinary tract infections in Singapore: a microbiological study.

We studied 214 patients with culture proven community acquired infections. A total of 219 organisms were isolated, of which 68.2% were Escherichia coli, 10.1% Klebsiella sp and 5.5% Proteus mirabilis. Gram positive cocci accounted for 10.5% of organisms isolated. The majority of organisms isolated were sensitive to nalidixic acid (81.1%), nitrofurantoin (80.7%), cephalexin (74.7%) and trimethoprim-sulphamethoxazole (65.0%). Resistance to ampicillin was common (49.8%), as such the use of ampicillin in community acquired urinary tract infections will result in a high failure rate.

Adolescent↗
PubMed1992

Prevalence of bacterial agents of diarrhoeal disease at the National University Hospital, Singapore and their resistance to antimicrobial agents.

Over a 50-month period, 4,508 stool specimens from patients with diarrhoea were bacteriologically examined at the National University Hospital, Singapore. Salmonella serotypes other than the typhoid and paratyphoid bacilli were the most common finding, being isolated in 10.8% of cases. Campylobacter jejuni was unexpectedly infrequent (1.9%); Aeromonas hydrophila was found in 1.8%. No other aerobic pathogen occurred in more than 1% of cases. Clostridium difficile was sought only when requested, and was isolated from 9.6% of cases tested. Testing for enteropathogenic Escherichia coli was limited to children under 1 year old. Gentamicin was active against the greatest number of aerobic isolates, followed by chloramphenicol and cotrimoxazole. The C. difficile isolates were all sensitive to metronidazole.

Aeromonas hydrophila↗