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Biomedical subjects

J Ling

Publications and source records attributed to J Ling.

At least 109 records · Page 6Linked to original sources
PubMed1988

Mandibular pathology presenting as a parotid tumour.

Swelling in the parotid region is often the presenting sign of a tumour of salivary gland origin. However, the possibility of disease involving adjacent structures must always be considered. Three cases are presented where pathology of the mandibular ramus presented as swelling in the parotid region. A clinical diagnosis of a parotid tumour was made, parotidectomy scheduled, and in two cases carried out before the correct diagnosis was reached. Difficulties of differential diagnosis are discussed, and imaging techniques reviewed. The value of plain radiographs of the adjacent hard tissues is emphasised. Careful interpretation should be based on a sound understanding of pathology of the jaws.

Aged↗
PubMed1988

Susceptibility of Hong Kong isolates of methicillin-resistant Staphylococcus aureus to antimicrobial agents.

Two hundred and sixty-six non-replicate Hong Kong isolates of methicillin-resistant Staphylococcus aureus were tested for their susceptibility to various anti-staphylococcal agents. Multiple resistance was common. More than 95% of patient isolates were resistant to both gentamicin and tetracycline, 68% to erythromycin, 37% to chloramphenicol, 10% to trimethoprim, 5% to rifampicin and 2% to fusidic acid. No isolate was resistant to all these agents, but nineteen different patterns of resistance were identified. Selected gentamicin-resistant isolates were tested against other aminoglycosides, and were sensitive to amikacin and netilmicin. The pattern of aminoglycoside resistance indicated that all isolates produced the aminoglycoside-modifying enzymes APH-(2") and AAC-(6')-I. All isolates were sensitive to vancomycin and teicoplanin. A single strain was resistant to three of the five quinolones tested, but resistance to all the quinolones could be induced easily in vitro by exposure to increasing subinhibitory concentrations of norfloxacin in broth.

Anti-Bacterial Agents↗
PubMed1988

Susceptibilities of Hong Kong isolates of multiply resistant Shigella spp. to 25 antimicrobial agents, including ampicillin plus sulbactam and new 4-quinolones.

Seventy-two percent of 129 shigella isolates from two Hong Kong hospitals were Shigella flexneri. Twenty-six percent were S. sonnei, and there was only one isolate each of S. dysenteriae and S. boydii. Ninety-six percent of the isolates were resistant to two or more antibiotics, and up to 11 resistances were seen in a single isolate. Fifty-seven percent or more of these isolates were resistant to ampicillin, streptomycin, tetracycline, chloramphenicol, and sulfamethoxazole; and up to twenty-three percent were resistant to kanamycin, trimethoprim, trimethoprim-sulfamethoxazole, and gentamicin. All the isolates were susceptible to amikacin, nalidixic acid, and the newer 4-quinolone agents; and all but one were susceptible to the cephalosporins tested. Only three isolates remained resistant to ampicillin in the presence of sulbactam. Ampicillin plus sulbactam or the newer 4-quinolone agents may be alternatives for the treatment of severe infections caused by multiply resistant shigellas.

Ampicillin↗
PubMed1988

Analysis of antimicrobial susceptibility results using microcomputers.

A computer program has been developed on an IBM-PC-compatible microcomputer to analyze antimicrobial susceptibility results of large numbers of organisms tested against a variety of antimicrobial agents. For each species, the output includes the numbers, percentages, cumulative numbers, and cumulative percentages of organisms inhibited at different concentrations of each drug, the MICs for 50 and 90% of organisms tested, MIC ranges, and geometric mean MICs. The distributions of MICs are also plotted as histograms. The program was written in dBASE III command language, but a compiled version allows rapid program execution independently of the dBASE III package.

Microbial Sensitivity Tests↗
PubMed1987

Occurrence of multiple antibiotic resistance and R-plasmids in gram-negative bacteria isolated from faecally contaminated fresh-water streams in Hong Kong.

The bacterial populations of six freshwater streams in populated areas of the Hong Kong New Territories were studied. There is considerable faecal contamination of these streams, with coliform counts as high as 10(5) c.f.u./ml and the contaminating organisms show a high prevalence of antibiotic resistance and multiple resistance. With direct plating of water samples onto antibiotic-containing media, an average of 49% of the gram-negative bacteria were ampicillin-resistant, 3% chloramphenicol-resistant and 1% gentamicin-resistant. At individual sites resistance to these drugs was as high as 98%, 8% and 3% respectively. More than 70% of strains were resistant to two or more antibiotics, 29% to five or more and 2% to eight or more. A total of 98 patterns of antibiotic resistance were detected with no one pattern predominating. Twenty-eight gram-negative bacterial species were identified as stream contaminants. Escherichia coli was the commonest bacterial species isolated and other frequent isolates were Enterobacter sp., Klebsiella sp. and Citrobacter sp., but no enteric pathogens were detected. The greatest prevalence of resistance and multiple resistance was associated with the heaviest contamination by E. coli. Analysis of selected stream isolates revealed multiple plasmid bands arranged in many different patterns, but multiple antibiotic resistances were shown to be commonly mediated by single transferable plasmids. Faecally-contaminated freshwater streams in Hong Kong may be reservoirs of antibiotic resistance plasmids for clinically-important bacteria.

Animals↗
PubMed1987

Salmonella serotypes and incidence of multiply-resistant Salmonellae isolated from diarrhoeal patients in Hong Kong from 1973-82.

Salmonella was the most frequent bacterial pathogen isolated from patients with acute diarrhoea in Hong Kong. In Queen Mary Hospital, the major hospital on Hong Kong Island, 94.7% of salmonellae isolated from faecal specimens from patients during the period 1973-82 belonged to the gastroenteric group, while 5.3% belonged to the enteric fever group. Amongst the gastroenteric group, 68 salmonella serotypes were identified, with Salmonella derby, S. typhimurium and S. anatum being the predominant ones. Three outbreaks caused by S. johannesburg, S. worthington and S. wandsworth were detected. Of S. typhimurium, 61.6% were resistant to multiple antibiotics and belonged to four major phage types: 193, 22, 138 and U288. The majority (96.8%) of S. johannesburg strains which caused a widespread epidemic were multiply-resistant. Multiple antibiotic resistance was rarely observed in most other gastroenteric salmonellae. S. typhi was the commonest of the enteric fever group isolated from the blood of patients. Nineteen phage types were identified; E1 being the commonest (18.5%) while 21% were nontypable. Many of these isolated were resistant to streptomycin or sulphadiazine, but none were resistant to ampicillin, chloramphenicol or trimethoprim.

Bacteriophage Typing↗
PubMed1987

Incidence of plasmids in multiply-resistant Salmonella isolates from diarrhoeal patients in Hong Kong from 1973-82.

Plasmids present in multiply-resistant salmonella strains including Salmonella typhimurium, S. johannesburg, S. wandsworth, S. derby, S. newport, S. london and S. choleraesuis causing diarrhoea in patients in Queen Mary Hospital in Hong Kong from 1973-82 were studied. In multiply-resistant S. typhimurium, plasmids belonging to groups FIme, H1 or H2 and plasmids encoding trimethoprim-resistance which were compatible with standard plasmids of testable incompatibility groups were detected. In S. johannesburg, both the ASTCKSu- and ASCKSu-resistant strains which were predominant in two consecutive periods of an outbreak were found to harbour the same plasmid which belonged to the incompatibility group FIme. S. wandsworth strains isolated from a hospital outbreak in 1980 harboured an identical R-plasmid belonging to group N. A few strains of the other salmonellae showing resistance to multiple antibiotics were found to harbour R-plasmids belonging to groups H1, H2 and FIme. The only salmonella of the enteric fever group resistant to ampicillin, chloramphenicol and trimethoprim was an S. paratyphi B strain. The resistances were encoded on a plasmid of an unknown incompatibility group. The occurrence and distribution of plasmids in these salmonellae isolated within the 10-year period are discussed.

DNA, Bacterial↗
PubMed1983

Antibiotic susceptibility of pneumococci and Haemophilus influenzae isolated from patients with acute exacerbations of chronic bronchitis: prevalence of tetracycline-resistant strains in Hong Kong.

The susceptibility of 119 respiratory isolates of Haemophilus influenzae and 87 respiratory isolates of Streptococcus pneumoniae to various antibiotics was tested by means of an agar dilution method and an inoculum size of 10(3) colony forming units (c.f.u.). The antibiotics tested included penicillin/ampicillin, erythromycin, tetracycline, chloramphenicol and four third-generation cephalosporins, cefotaxime, cefoperazone, ceftriaxone and moxalactam. Fifty-eight per cent of the pneumococcal strains and 23 per cent of the H. influenzae strains tested were found resistant to tetracycline (MICs = 4-128 mg/l and 4-64 mg/l, respectively). None of the isolates tested was resistant to erythromycin or chloramphenicol. Three per cent of Haemophilus strains tested were beta-lactamase producing and thus resistant to ampicillin (MICs = 2-8 mg/l), while none of the pneumococcal strains tested was penicillin-resistant. Three of the newer third-generation cephalosporins--cefotaxime, cefoperazone and ceftriaxone--were highly active against both H. influenzae and Str. pneumoniae while moxalactam, though also active, was comparatively less effective.

Anti-Bacterial Agents↗
PubMed1983

Susceptibility of blood isolates to various antibiotics, in particular to cephalosporins.

Of 760 bacterial pathogens isolated from blood cultures of acutely ill patients in a general hospital in Hong Kong for 1 year, 69.9% of the isolates were Gram-negative aerobes mainly Escherichia coli and Klebsiella pneumoniae, 22.0% were Gram-positive aerobes mainly Staphylococcus aureus and enterococci and 8.1% were anaerobes mainly Bacteroides spp. The susceptibility of the aerobic isolates to various antibiotics was tested. Ampicillin was found to be active mainly against the enterococci and some other Gram-positive organisms while most isolates of Staph. aureus and the Gram-negative bacteria were resistant. In contrast, cephalothin was found only slightly less active than the second generation cephalosporins against Gram-negative blood isolates but considerably more active against Staph. aureus and other Gram-positive isolates. The three aminoglycosides tested, i.e., gentamicin, tobramycin and amikacin, showed similar good activity against E. coli, K. pneumoniae and Proteus mirabilis, but amikacin had the broadest spectrum of activity in inhibiting most of the other Gram-negative isolates as well as isolates of Staph. aureus. The third generation cephalosporins, cefotaxime, cefoperazone, latamoxef (moxalactam), ceftriaxone and ceftazidime, all had a high activity against the Gram-negative but a reduced activity against the Gram-positive bacteria. Ceftazidime had the broadest spectrum of activity in inhibiting all the Gram-negative isolates including Pseudomonas aeruginosa, while cefotaxime showed the best overall activity against both Gram-positive and Gram-negative blood isolates.

Anti-Bacterial Agents↗
PubMed1983

Cefoperazone against carbenicillin-resistant isolates of Pseudomonas aeruginosa: comparison with other newer cephalosporins and N-formimidoyl thienamycin.

The in-vitro activities of cefoperazone, cefotaxime, ceftriaxone, latamoxef (moxalactam), ceftazidime and N-formimidoyl-thienamycin (N-f-thienamycin) were compared against clinical isolates of Pseudomonas aeruginosa that were resistant to carbenicillin and gentamicin, or against those which were susceptible. N-f-thienamycin and ceftazidime were more active than cefotaxime, ceftriaxone and latamoxef only against carbenicillin-susceptible isolates: isolates resistant to carbenicillin exhibited markedly increased resistance to cefoperazone, but not to N-f-thienamycin or ceftazidime. A partial cross-resistance was observed between carbenicillin and cefoperazone. This was due to the presence in these Pseudomonas isolates of a plasmid-mediated beta-lactamase which was active against carbenicillin and cefoperazone but not against cefotaxime, ceftriazone and latamoxef.

Carbenicillin↗