Reasonable Rascal
07-01-02, 12:16
SALMONELLA NEWPORT, MULTIRESISTANT - USA: ALERT
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A ProMED-mail post
<http://www.promedmail.org>
Date: 29 June 2002
Source: MMWR Morb Mortal Wkly Rep 2002; 51 (25): 545-8 ( Jun 28 ) [edited]
<http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5125a1.htm>
Outbreak of multidrug-resistant Salmonella newport -- US, Jan-Apr 2002
-------------------------
During Jan-Apr 2002, _Salmonella enterica_ serotype Newport (_S._ Newport) was isolated from 47 people in 5 states: New York (34 cases), Michigan (5), Pennsylvania (4), Ohio (2), and Connecticut (2).
Antimicrobial-susceptibility testing of 3 isolates by the Centers for Disease Control and Prevention (CDC) revealed resistance to amoxicillin/clavulanate, ampicillin, cefoxitin, ceftiofur, cephalothin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracycline. In addition, 2 of 3 isolates were resistant to kanamycin; 2 had decreased susceptibility or resistance to ceftriaxone.
To determine the cause of the outbreak, the New York State Department of Health (NYSDOH) and CDC conducted a case control study. This report summarizes the results of this investigation, which implicated exposure to raw or undercooked ground beef as the vehicle of transmission. The findings also highlight the emergence of multidrug-resistant _S._ Newport in the United States. These strains exhibit decreased susceptibility or resistance to ceftriaxone, thereby complicating empirical therapy for serious salmonella infections. Clinicians should be informed of the emergence of these _S._ Newport strains, and people should avoid eating undercooked ground beef and wash their hands after handling raw ground beef.
[MMWR] editorial note:
An estimated 1.4 million cases of salmonellosis occur annually in the United States. _S._ Newport is the third commonest salmonella serotype in the US. During 1997-2001, the number of laboratory confirmed _S._ Newport infections reported to CDC increased from 1584 (5 per cent) of 34 608 reported salmonella infections to 3152 (10 per cent) of 31 607 (CDC, unpublished data, 2002). The increasing number of _S._ Newport infections in the US appears to be associated with the emergence and rapid dissemination of multidrug-resistant strains of _S._ Newport.
Since 1996, the National Antimicrobial Resistance Monitoring System (NARMS) for Enteric Bacteria has identified an increasing number of _S._ Newport isolates that are resistant to at least 9 of 17 antimicrobial agents tested: amoxicillin/clavulanate, ampicillin, cefoxitin, ceftiofur, cephalothin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracycline. In addition, these isolates exhibit decreased susceptibility (minimal inhibitory concentrations [MIC] more than 16 micrograms/mL) or resistance (MIC more than 64 micrograms/mL) to ceftriaxone, an antimicrobial agent commonly used to treat serious infections in children. Isolates with this resistance pattern have plasmids that carry a blaCMY gene. These genes produce AmpC-type enzymes, which confer resistance to penicillin-inhibitor combinations (for example, amoxicillin/clavulanate), cephamycins (for example, cefoxitin), and expanded-spectrum cephalosporins (for example, ceftiofur and ceftriaxone). To distinguish this type of resistance from other multidrug-resistant strains, these strains are referred to as Newport MDR-AmpC. In 1998, 1 (1 per cent) of 78 _S._ Newport isolates tested in NARMS was Newport MDR-AmpC compared with 33 (26 per cent) of 128 in 2001. Although the full clinical significance of Newport MDR-AmpC is unknown, treatment of these infections with ceftriaxone might be ineffective. In addition, antimicrobial-resistant salmonella infections have been associated with an increased hospital admission rate, morbidity, and mortality.
In 2001 and 2002 several state health departments, including California, Connecticut, and Massachusetts documented association of exposure to dairy farms, ill cattle, and cheese made from unpasteurized milk with increased human _S. Newport_ MDR-AmpC infections. In the outbreak described in this report, most patients for whom information is available ate lean or extra-lean ground beef; dairy cattle are an important source of lean or extra-lean ground beef. These data suggest that cattle, particularly dairy cattle, might be a source for human Newport MDR-AmpC infection.
This report is the first to associate eating of ground beef, specifically raw or undercooked ground beef, with Newport MDR-AmpC infection. Recent US surveys indicate that 11 to 28 per cent of people report eating raw or undercooked ground beef, and about a third of people do not use safe food handling practices to prevent cross contamination in the kitchen.
The USDA Pathogen Reduction/Hazard Analysis and Critical Control Points (PR/HACCP) inspection system in meat and poultry plants has reduced salmonella prevalence in raw ground beef from 7.5 per cent in 1998 to 2.8 per cent in 2001. The emergence of Newport MDR-AmpC suggests that further measures may be necessary. Potential strategies include 1) evaluating practices on the farm to determine factors that might contribute to multidrug-resistant _S._ Newport and developing interventions to eliminate these factors; 2) implementing the Public Health Action Plan to Combat Antimicrobial Resistance; 3) encouraging industry to implement processes such as steam pasteurization or irradiation of ground beef; and 4) increasing efforts to educate consumers on the importance of safe handling and cooking practices.
State health departments and veterinarians should investigate clusters of _S._ Newport and perform antimicrobial-susceptibility testing to determine if isolates are Newport MDR-AmpC. Epidemiological investigations and pulse field gel electrophoresis comparison of outbreak isolates will help to identify food vehicles associated with Newport MDR-AmpC and to identify control points for reducing these infections. Because treatment with ceftriaxone might be ineffective, clinicians should be informed of the emergence of Newport MDR-AmpC strains. People should not eat undercooked ground beef and should wash their hands after handling raw ground beef.
--
ProMED-mail
[This report in MMWR highlights the significance of _S. enterica_ serotype Newport not only in numbers but also related to the increase in multidrug resistance strains of the organism. Epidemiological investigations have linked the strain to exposure to undercooked ground beef. As emphasized above, and previously in ProMED-mail postings about contamination of ground beef with _Escherichia coli_ O157:H7, even if food is contaminated the risk to humans can be avoided by strict adherence to appropriate food handling and adequate cooking.
The resistance pattern of these isolates limits potential treatment modalities, especially in children and in pregnant women, in whom quinolones are not generally used because of potential side effects. It should be remembered, however, that most _Salmonella enterica_ infections are self limiting and do not require specific antimicrobial therapy. - Mod.LL]
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Fair Use for Education. Any reproduction must include full credit to original source.
***********************************************
A ProMED-mail post
<http://www.promedmail.org>
Date: 29 June 2002
Source: MMWR Morb Mortal Wkly Rep 2002; 51 (25): 545-8 ( Jun 28 ) [edited]
<http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5125a1.htm>
Outbreak of multidrug-resistant Salmonella newport -- US, Jan-Apr 2002
-------------------------
During Jan-Apr 2002, _Salmonella enterica_ serotype Newport (_S._ Newport) was isolated from 47 people in 5 states: New York (34 cases), Michigan (5), Pennsylvania (4), Ohio (2), and Connecticut (2).
Antimicrobial-susceptibility testing of 3 isolates by the Centers for Disease Control and Prevention (CDC) revealed resistance to amoxicillin/clavulanate, ampicillin, cefoxitin, ceftiofur, cephalothin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracycline. In addition, 2 of 3 isolates were resistant to kanamycin; 2 had decreased susceptibility or resistance to ceftriaxone.
To determine the cause of the outbreak, the New York State Department of Health (NYSDOH) and CDC conducted a case control study. This report summarizes the results of this investigation, which implicated exposure to raw or undercooked ground beef as the vehicle of transmission. The findings also highlight the emergence of multidrug-resistant _S._ Newport in the United States. These strains exhibit decreased susceptibility or resistance to ceftriaxone, thereby complicating empirical therapy for serious salmonella infections. Clinicians should be informed of the emergence of these _S._ Newport strains, and people should avoid eating undercooked ground beef and wash their hands after handling raw ground beef.
[MMWR] editorial note:
An estimated 1.4 million cases of salmonellosis occur annually in the United States. _S._ Newport is the third commonest salmonella serotype in the US. During 1997-2001, the number of laboratory confirmed _S._ Newport infections reported to CDC increased from 1584 (5 per cent) of 34 608 reported salmonella infections to 3152 (10 per cent) of 31 607 (CDC, unpublished data, 2002). The increasing number of _S._ Newport infections in the US appears to be associated with the emergence and rapid dissemination of multidrug-resistant strains of _S._ Newport.
Since 1996, the National Antimicrobial Resistance Monitoring System (NARMS) for Enteric Bacteria has identified an increasing number of _S._ Newport isolates that are resistant to at least 9 of 17 antimicrobial agents tested: amoxicillin/clavulanate, ampicillin, cefoxitin, ceftiofur, cephalothin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracycline. In addition, these isolates exhibit decreased susceptibility (minimal inhibitory concentrations [MIC] more than 16 micrograms/mL) or resistance (MIC more than 64 micrograms/mL) to ceftriaxone, an antimicrobial agent commonly used to treat serious infections in children. Isolates with this resistance pattern have plasmids that carry a blaCMY gene. These genes produce AmpC-type enzymes, which confer resistance to penicillin-inhibitor combinations (for example, amoxicillin/clavulanate), cephamycins (for example, cefoxitin), and expanded-spectrum cephalosporins (for example, ceftiofur and ceftriaxone). To distinguish this type of resistance from other multidrug-resistant strains, these strains are referred to as Newport MDR-AmpC. In 1998, 1 (1 per cent) of 78 _S._ Newport isolates tested in NARMS was Newport MDR-AmpC compared with 33 (26 per cent) of 128 in 2001. Although the full clinical significance of Newport MDR-AmpC is unknown, treatment of these infections with ceftriaxone might be ineffective. In addition, antimicrobial-resistant salmonella infections have been associated with an increased hospital admission rate, morbidity, and mortality.
In 2001 and 2002 several state health departments, including California, Connecticut, and Massachusetts documented association of exposure to dairy farms, ill cattle, and cheese made from unpasteurized milk with increased human _S. Newport_ MDR-AmpC infections. In the outbreak described in this report, most patients for whom information is available ate lean or extra-lean ground beef; dairy cattle are an important source of lean or extra-lean ground beef. These data suggest that cattle, particularly dairy cattle, might be a source for human Newport MDR-AmpC infection.
This report is the first to associate eating of ground beef, specifically raw or undercooked ground beef, with Newport MDR-AmpC infection. Recent US surveys indicate that 11 to 28 per cent of people report eating raw or undercooked ground beef, and about a third of people do not use safe food handling practices to prevent cross contamination in the kitchen.
The USDA Pathogen Reduction/Hazard Analysis and Critical Control Points (PR/HACCP) inspection system in meat and poultry plants has reduced salmonella prevalence in raw ground beef from 7.5 per cent in 1998 to 2.8 per cent in 2001. The emergence of Newport MDR-AmpC suggests that further measures may be necessary. Potential strategies include 1) evaluating practices on the farm to determine factors that might contribute to multidrug-resistant _S._ Newport and developing interventions to eliminate these factors; 2) implementing the Public Health Action Plan to Combat Antimicrobial Resistance; 3) encouraging industry to implement processes such as steam pasteurization or irradiation of ground beef; and 4) increasing efforts to educate consumers on the importance of safe handling and cooking practices.
State health departments and veterinarians should investigate clusters of _S._ Newport and perform antimicrobial-susceptibility testing to determine if isolates are Newport MDR-AmpC. Epidemiological investigations and pulse field gel electrophoresis comparison of outbreak isolates will help to identify food vehicles associated with Newport MDR-AmpC and to identify control points for reducing these infections. Because treatment with ceftriaxone might be ineffective, clinicians should be informed of the emergence of Newport MDR-AmpC strains. People should not eat undercooked ground beef and should wash their hands after handling raw ground beef.
--
ProMED-mail
[This report in MMWR highlights the significance of _S. enterica_ serotype Newport not only in numbers but also related to the increase in multidrug resistance strains of the organism. Epidemiological investigations have linked the strain to exposure to undercooked ground beef. As emphasized above, and previously in ProMED-mail postings about contamination of ground beef with _Escherichia coli_ O157:H7, even if food is contaminated the risk to humans can be avoided by strict adherence to appropriate food handling and adequate cooking.
The resistance pattern of these isolates limits potential treatment modalities, especially in children and in pregnant women, in whom quinolones are not generally used because of potential side effects. It should be remembered, however, that most _Salmonella enterica_ infections are self limiting and do not require specific antimicrobial therapy. - Mod.LL]
--------------------------------------------------
Fair Use for Education. Any reproduction must include full credit to original source.