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L R Ward

Publications and source records attributed to L R Ward.

At least 37 records · Page 2Linked to original sources
PubMed2000

Antimicrobial drug resistance in non-typhoidal salmonellas from humans in England and Wales in 1999: decrease in multiple resistance in Salmonella enterica serotypes Typhimurium, Virchow, and Hadar.

In 1999 the incidence of multiple drug resistance (to four or more antimicrobials) in non-typhoidal salmonellas from humans in England and Wales fell in isolations of Salmonella enterica serotypes Typhimurium, Virchow, and Hadar. This fall has been most noticeable in S. Typhimurium, where 59% of isolates were multiresistant compared to 81% in 1996. The main reason for this has been a 75% decline in isolations of multiply-resistant S. Typhimurium definitive phage type (DT) 104 (MR DT104) since 1996. Nevertheless MR DT104 remains second to S. Enteritidis phage type 4 as the most common strain in cases of human salmonellosis in England and Wales. Multiple resistance has also remained high in S. Hadar, with 49% of isolates resistant to four drugs or more compared to 56% in 1996. Isolates with decreased sensitivity to ciprofloxacin (minimal inhibitory concentration: 0.25-1.0 mg/L) have increased in incidence in S. Enteritidis, S. Virchow, and S. Hadar; in S. Hadar 70% of isolates were resistant to ciprofloxacin at this level. It is hoped that Codes of Practice introduced by some pharmaceutical companies, governments, professional organisations, and others to combat the unnecessary prophylactic use of fluoroquinolones in animal husbandry will not result in a reduction in the incidence of resistance to ciprofloxacin in salmonella organisms causing infections in humans.

Anti-Bacterial Agents↗
PubMed2000

Multiple clones within multidrug-resistant Salmonella enterica serotype Typhimurium phage type DT104. The Greek Nontyphoidal Salmonella Study Group.

Six distinct clones were present among Greek multidrug-resistant Salmonella enterica serotype Typhimurium phage type DT104, since isolates belonging to resistance phenotypes including the ACSSuT (ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline) core could be distinguished with respect to their pulsed-field gel electrophoresis patterns, int1 integron structures, and presence or absence of antibiotic resistance genes ant(3'')-Ia, pse-1, and tem-1.

Animals↗
PubMed2000

Spread of resistance from food animals to man--the UK experience.

Since 1990 there have been dramatic increase in the occurrence multiply drug-resistant strains of zoonotic pathogens causing infections in humans in many developed countries. Of particular note has been the epidemic spread of MR strains of S. typhimurium DT 104, which now appear to have an almost world-wide distribution. Within DT104 the increasing spectrum of resistance is of considerable concern, with strains with decreased susceptibility to ciprofloxacin increasing in incidence in the United Kingdom and also causing serious disease in humans in other countries. For campylobacters the incidence of ciprofloxacin-resistant organisms is also increasing, with reports of such isolates from numerous countries throughout the world. For VTEC O157, although resistance is increasing, multiple resistance and resistance to ciprofloxacin remains rare. Drug resistance in food-borne pathogens is an unfortunate but almost inevitable consequence of the use of antimicrobials in food animals. Although for some pathogens--e.g., Campylobacter spp., the use of antimicrobials in human medicine is also an important factor (Smith el al 1999), it is the use of antimicrobials in food animals which has been a major factor in the development of decreased susceptibility to antibiotics such as ciprofloxacin in zoonotically-transmitted salmonellas. Such use is quite legitimate. However it is regrettable that recommendations such as propounded in 1992 in the UK by the Expert Group on Animal Feedingstuffs--the Lamming Committee, that any new antibiotics with cross resistance to those used in human medicine should not be used for prophylaxis in animal husbandry, were not accepted (Anonymous, 1992). Although the clock cannot be turned back, to combat the development of resistance to such important drugs as the fluoroquinolones it is hoped that a Code of Practice for their use in food animals will soon be internationally implemented.

Animal Husbandry↗
PubMed1999

Harmonization of antibiotic susceptibility testing for Salmonella: results of a study by 18 national reference laboratories within the European Union-funded Enter-net group.

For the effective surveillance of antimicrobial drug resistance within Salmonella organisms from humans, harmonization of methods used for sensitivity testing by laboratories responsible for the typing of such organisms is essential. A study of resistance or sensitivity to a panel of 11 antimicrobials by the Enter-net international surveillance network was therefore undertaken. There are 18 national Salmonella reference laboratories within this European Union-funded network. Forty-eight strains of Salmonella enterica were distributed to each laboratory for testing for resistance or sensitivity to ampicillin, cefotaxime, chloramphenicol, gentamicin, kanamycin, streptomycin, sulfonamides, tetracyclines, trimethoprim, nalidixic acid, and ciprofloxacin. Over 8,500 tests were assessed involving disk diffusion (DD), agar breakpoint (BP), or full minimum inhibitory concentration (MIC). Results indicated that whichever method was used, there was a high degree of concordance for the detection of resistance to most antimicrobials; only for decreased sensitivity to ciprofloxacin was there substantial nonconcordance. Because all isolates with decreased sensitivity to ciprofloxacin were resistant to nalidixic acid, it is suggested that, if required, MICs to ciprofloxacin could be determined for isolates resistant to nalidixic acid. For the detection of sensitivity, the main area of nonconcordance was in the detection of sensitivity to streptomycin. With the exception of decreased sensitivity to ciprofloxacin, we are confident that a database of antimicrobial susceptibilities can now be established and harmonized antibiogram data for Salmonella can now be exchanged for national Salmonella reference laboratories within the European Union.

Drug Resistance, Microbial↗
PubMed1999

Pulsed field gel electrophoresis identifies an outbreak of Salmonella enterica serotype Montevideo infection associated with a supermarket hot food outlet.

In February 1996 Salmonella enterica serotype Montevideo infection in a patient in the North Tyneside area was attributed to consumption of cooked chicken bought from a supermarket hot food outlet. Isolates from the patient, leftover food, and environmental samples were indistinguishable by pulsed field gel electrophoresis (PFGE). PFGE also demonstrated that an outbreak of infection with S. Montevideo associated with the hot food outlet had occurred in late 1995 and early 1996. This study shows the importance of microbial strain discrimination in outbreak investigations and illustrates the value of close liaison between microbiologists, epidemiologists, and environmental health officers in the control of salmonella outbreaks.

Aged↗
PubMed1998

National outbreak of Salmonella senftenberg associated with infant food.

Eight cases of Salmonella senftenberg infection in infants were identified in the first half of 1995 in England, five were indistinguishable S. senftenberg strains. A case-control study showed an association between illness and consumption of one brand of baby cereal (P = 0.03). The cereal manufacturer reported isolating S. senftenberg in June 1994 from an undistributed cereal batch. Outbreak strains and the cereal strain were all plasmid-free in contrast to other human isolates of S. senftenberg in the same period. Changes in the production process were implemented to prevent further contamination. Surveillance centres should strengthen the detection and investigation of outbreaks of gastrointestinal infection in susceptible groups, especially young children. In this outbreak, the study of only five cases led to identification of the vehicle of infection. Even when few cases are reported, epidemiological investigation in conjunction with molecular typing may lead to public health action which prevents continuing or future outbreaks.

Case-Control Studies↗
PubMed1998

Molecular fingerprinting defines a strain of Salmonella enterica serotype Anatum responsible for an international outbreak associated with formula-dried milk.

Molecular analyses based on plasmid profile typing and pulsed-field gel electrophoresis have defined a strain of Salmonella enterica serotype Anatum associated with the consumption of a particular brand of formula-dried milk responsible for an outbreak in late 1996/early 1997 involving 15 infants and 2 relatives in the UK, and 2 infants in France. The study has demonstrated the value of laboratory-based surveillance involving identification of the outbreak strain at the molecular level coupled with food microbiology and targeted epidemiological investigations, and has highlighted the importance of rapid communication and subsequent international collaboration through the European Union-funded Salm-Net salmonella surveillance network.

Animals↗
PubMed1998

Pulsed-field electrophoretic fingerprinting of Salmonella indiana and its epidemiological applicability.

Eight Xba I-generated pulsed-field profile (PFP) types and four subtypes within one of the most common PFP types have been identified in Salmonella indiana from patients, poultry and human food in England and Wales in the three-year period from January 1994 to December 1996. Two PFP types have predominated, PFP X1 and PFP X2. Although the PFP X1 type was identified throughout the study period, the PFP X2 type was not identified until late 1995, subsequently becoming the most common PFP type in humans in the first six months of 1996 with a significant distribution in elderly patients. It is concluded that PFGE can be used in support of epidemiological investigations for the subdivision of Salm. indiana. Furthermore, as both conditions and interpretation criteria can be easily standardized, it is suggested that for many salmonella serotypes, PFGE can provide the basis for a definitive scheme of genotypic subtyping suitable for epidemiological investigations at both a national and international level.

Aged↗
PubMed1998

Phage types of Australian isolates of Salmonella enterica subsp. enterica serovar Virchow.

Australian isolates (79) of Salmonella enterica subsp. enterica serovar Virchow (Salmonella Virchow) were characterized by phage typing. Thirteen phage types were identified, of which phage type (PT) 8, representing 54 of 79 isolates, was predominant, as it had been in England and Wales up to 1994 when it was replaced by PT26. Other phage types identified in Australia were distinct from those observed in England and Wales. This suggests that PT8 may be a global phage type, while others may be distinct to particular geographical regions.

Animals↗
PubMed1998

An immunoblotting procedure comprising O = 9,12 and H = d antigens as an alternative to the Widal agglutination assay.

AIMS: To compare the established Widal agglutination assay with an immunoblotting procedure. METHODS: 110 sera were used to compare the established Widal agglutination assay with an immunoblotting procedure incorporating lipopolysaccharide (LPS) (O = 9,12) and flagellar (H = d) antigens. RESULTS: Antibodies to the LPS antigens were detected in 18 sera by the Widal assay and in 37 by immunoblotting. Antibodies to the flagellar antigens were detected in 27 sera by Widal assay and in 25 by immunoblotting. CONCLUSIONS: An immunoblotting procedure incorporating O = 9,12 LPS and H = d flagellar antigens was rapid and more sensitive than the established Widal agglutination assay for providing evidence of infection with S typhi.

Agglutination Tests↗
PubMed1997

Application of molecular methods to a nosocomial outbreak of Salmonella enteritidis phage type 4.

A nosocomial outbreak of Salmonella enteritidis phage type 4 occurred in July 1995. Seven definite cases were identified over 13 days affecting four wards in a London hospital. The outbreak strain was characterized by plasmid profile typing and pulsed-field gel electrophoresis (PFGE), and was unusual in that it did not possess a 38 MDa plasmid common to most isolates of S. enteritidis PT 4 made from humans and food animals in England and Wales. Seven asymptomatic excreters were identified on screening. No additional cases occurred on wards after standard isolation procedures were implemented. No common or continuing food or dietary source was identified. Results of epidemiological, microbiological and environmental investigations suggested that the outbreak was due to person-to-person transmission within the hospital. The source of the outbreak was not established but was probably due to admission of a patient with an unrecognized infection of S. enteritidis PT 4. The study highlights the importance of close collaboration between hospital staff, epidemiologists and microbiologists, and demonstrates the value of molecular techniques for strain subdivision in outbreak investigations.

Aged↗
PubMed1997

Increase in multiple antibiotic resistance in nontyphoidal salmonellas from humans in England and Wales: a comparison of data for 1994 and 1996.

The incidence of multiple drug resistance (to four or more antimicrobials) in salmonellas from humans in England and Wales in 1996 has been compared with corresponding data for 1994. For Salmonella enteritidis multiple resistance has remained rare, although a high proportion of isolates of phage type 6A have shown resistance to ampicillin. For S. typhimurium multiple resistance has continued to increase, with 81% of isolates now multiresistant. Of particular importance in S. typhimurium has been the continued epidemic of multiresistant DT 104 and the increasing occurrence of strains of this phage type with additional resistance to trimethoprim and/or ciprofloxacin. For S. virchow, a 10% increase in multiple resistance is mainly concentrated in two phage types common in returning travellers. For S. hadar, there has been a substantial increase in the incidence of multiple resistance with over 50% of isolates now multiresistant. Substantial increases in the incidence of resistance to ciprofloxacin in multiresistant S. typhimurium DT 104, S. virchow, and S. hadar since 1993, when the fluoroquinolone antibiotic enrofloxacin was licensed for veterinary use in the UK, are of particular concern.

Drug Resistance, Microbial↗
PubMed1997

Multidrug-resistant Salmonella typhi: a worldwide epidemic.

Since 1989, strains of Salmonella typhi resistant to chloramphenicol, ampicillin, and trimethoprim (i.e., multidrug-resistant [MDR] strains) have been responsible for numerous outbreaks in countries in the Indian subcontinent, Southeast Asia, and Africa. MDR strains have also been isolated with increasing frequency from immigrant workers in countries in the Arabian Gulf, as well as in developed countries from returning travelers. In all MDR strains so far examined, multiple resistance has been encoded by plasmids of the H1 incompatibility group. As a result of the widespread dissemination of such strains, chloramphenicol can no longer be regarded as the first-line drug for typhoid fever. Because strains are also resistant to ampicillin and trimethoprim, the efficacy of these antibiotics has also been impaired, and ciprofloxacin is now the drug of choice for typhoid fever. Chromosomally encoded resistance to ciprofloxacin has now been observed in a small number of strains isolated in the United Kingdom from patients returning from the Indian subcontinent, and in at least one case the patient did not respond to treatment with this antibiotic. It is regrettable that resistance to ciprofloxacin has now emerged in MDR S. typhi, and it is of paramount importance to limit the unnecessary use of this vital drug so that its efficacy should not be further jeopardized.

Developed Countries↗
PubMed1997

Resistance to ciprofloxacin in pathogenic Enterobacteriaceae in England and Wales in 1996.

In 1996, 6% of Escherichia coli from extraintestinal infections were resistant to ciprofloxacin with minimum inhibitory concentrations (MICs) > or = 2 mg/l (high level resistance). Low level resistance (MIC 0.125-1 mg/l) was also identified in 7% of Salmonella typhi, 4% of S paratyphi A, and 4% of non-typhoidal salmonellas. However, resistance to ciprofloxacin was rarely identified in shigellas. For E coli, physicians should be aware that treatment failures may occur when patients with invasive illness are treated with ciprofloxacin before the results of laboratory sensitivity tests are available. For salmonellas an increasing number of treatment failures have been recorded for patients infected with strains with low level resistance. Because of the increasing incidence of Enterobacteriaceae with low level resistance to ciprofloxacin, it is recommended that for this group of organisms a breakpoint of 0.125 mg/l should be included in laboratory sensitivity tests.

Anti-Infective Agents↗