Cephalosporin and ciprofloxacin resistance in Salmonella, Taiwan.We report the prevalence and characteristics of Salmonella salmonella Any of the rod-shaped, gram-negative, non-oxygen-requiring bacteria that make up the genus Salmonella. Their main habitat is the intestinal tract of humans and other animals. strains resistant to ciprofloxacin ciprofloxacin /cip·ro·flox·a·cin/ (sip?ro-flok´sah-sin) a synthetic antibacterial effective against many gram-positive and gram-negative bacteria; used as the hydrochloride salt. cip·ro·flox·a·cin n. and extended-spectrum cephalosporins Cephalosporins Definition Cephalosporins are medicines that kill bacteria or prevent their growth. Purpose Cephalosporins are used to treat infections in different parts of the body—the ears, nose, throat, lungs, sinuses, and in Taiwan from January to May 2004. All isolates resistant to extended-spectrum cephalosporins carried [bla.sub.CMY-2], and all ciprofloxacin-resistant Salmonella enterica Salmonella enterica is a rod shaped, flagellated, Gram-negative bacterium, and a member of the genus Salmonella.[1] Serovars S. enterica has an extraordinarily large number of serovars serotype serotype /se·ro·type/ (ser´o-tip) the type of a microorganism determined by its constituent antigens; a taxonomic subdivision based thereon. se·ro·type n. See serovar. v. Choleraesuis isolates related. ********** Resistance to extended-spectrum cephalosporins (ESCs) or fluoroquinolones in Salmonella enterica has become a global concern (1). ESC See escape character and escape key. See also ESC/P. ESC - escape resistance in Salmonella strains is usually due to the production of plasmid-mediated extended-spectrum [beta]-lactamases (ESBLs) or AmpC [beta]-lactamases, and among these [beta]-lactamases, the CMY-2 AmpC enzyme has been reported most often (1-3). Resistance to fluoroquinolones in Salmonella strains is usually due to the accumulation of mutations in the quinolone resistance--determining regions (QRDRs) of DNA gyrase DNA gyrase (ji´ras) a type II DNA topoisomerase. genes (1,4,5). Resistance to both ESCs and fluoroquinolones remains extremely rare in salmonellae. In Taiwan, increasing resistance to fluoroquinolones and the emergence of CMY-2--producing ESC-resistant strains in salmonellae have been noted (3-6). The emergence of Salmonella strains resistant to both ceftriaxone ceftriaxone /cef·tri·ax·one/ (cef?tri-ak´son) a semisynthetic, ß–resistant, third-generation cephalosporin effective against a wide range of gram-positive and gram-negative bacteria, used as the sodium salt. and ciprofloxacin was reported more recently in Taiwan and may pose a serious therapeutic problem (7,8). We conducted the present study to investigate the prevalence and characteristics of Salmonella strains resistant to ciprofloxacin and ESCs in Taiwan. The Study From January to May 2004, a total of 600 Salmonella isolates from 585 patients were obtained from 5 medical centers and 14 district hospitals throughout Taiwan; these isolates were serotyped with commercial antisera (Difco, Detroit, MI, USA). The 4 most common serotypes of Salmonella enterica (Enteritidis, Typhimurium, Stanley, and Choleraesuis) accounted for 66.8% of all isolates. Two isolates were untypeable, and the remainder were typed into 42 serotypes (data not shown), which were each represented by 1 to 23 isolates. MICs of antimicrobial agents Antimicrobial agents Chemical compounds biosynthetically or synthetically produced which either destroy or usefully suppress the growth or metabolism of a variety of microscopic or submicroscopic forms of life. were determined by the agar dilution method (9). Resistance to ciprofloxacin (MIC [greater than or equal to] 4 [micro]g/mL) was seen in 50 (8.3%) isolates (Table 1); 20 (3.3%) were resistant (MICs ranging from 8 to >64 [micro]g/mL) to ceftazidime, ceftriaxone, cefotaxime, or aztreonam (Table 2); 6 isolates showed decreased susceptibilities to 1 or 2 of the 4 ESCs (MICs 0.5-2 [micro]g/mL); 10 (1.7%) isolates were resistant to both ciprofloxacin and ESCs. S. Choleraesuis had high rates of resistance to ciprofloxacin (84.4%), ESCs (17.8%), and both (17.8%). None of the 26 Salmonella isolates with resistance or decreased susceptibility to ESCs produced ESBL ESBL Extended Spectrum Beta Lactamase ESBL East Staffordshire Badminton League (UK) , according to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. the double-disk synergy method (10). Among the 20 ESC-resistant isolates, 10 isolates were ciprofloxacin-resistant, 4 isolates showed decreased susceptibility to ciprofloxacin (MIC 0.25-1 [micro]g/mL) and resistance to nalidixic acid nalidixic acid /nal·i·dix·ic ac·id/ (nal-i-dik´sik) a synthetic antibacterial agent used in the treatment of genitourinary infections caused by gram-negative organisms. na·li·dix·ic acid n. , and 6 isolates were susceptible to ciprofloxacin and nalidixic acid (Table 2). All 20 ESC-resistant isolates were susceptible to cefepime (MIC <0.03 [micro]g/mL) and imipenem (MIC <1 [micro]g/mL), and 17 isolates were resistant to >1 non-[beta]-lactam agent. All 20 ESC-resistant isolates expressed a [beta]-lactamase of pI 9.0 by isoelectric focusing isoelectric focusing, n the ordering and concentration of substances according to their isoelectric points. (3,11); 11 of these isolates expressed an additional pI 5.4 [beta]-lactamase (Table 2). [bla.sub.CMY-2] was detected in all ESC-resistant isolates, [bla.sub.TEM-1] was detected in the 11 isolates with the pI 5.4-[beta]-lactamase by polymerase chain reaction polymerase chain reaction (pŏl`ĭmərās') (PCR), laboratory process in which a particular DNA segment from a mixture of DNA chains is rapidly replicated, producing a large, readily analyzed sample of a piece of DNA; the process is (PCR PCR polymerase chain reaction. PCR abbr. polymerase chain reaction Polymerase chain reaction (PCR) ) and sequence analyses with the primers for the entire [bla.sub.TEM TEM 1. transmission electron microscope. 2. triethylenemelamine. 3. transmissible encephalopathy of mink. ]-related and [bla.sub.CMY-2]-related structural genes (2,3). The QRDR QRDR Quinolone Resistance-Determining Regions sequences of gyrA, gyrB, parC, and parE of the 20 ESC-resistant Salmonella isolates were determined by PCR and sequence analyses (5). All 10 ciprofloxacin-resistant isolates showed 2 mutations at the Ser-83 and Asp-87 codons in gyrA and a single mutation at the Ser-80 codon codon: see nucleic acid. in parC (Table 2). Four isolates with decreased susceptibility to ciprofloxacin had a single mutation at either the Ser-83 or the Asp-87 codon in gyrA. All 20 ESC-resistant isolates showed no mutations in the QRDRs of gyrB and parE. ESC resistance was transferred from 18 of the 20 ESC-resistant Salmonella isolates to Escherichia coli Escherichia coli (ĕsh'ərĭk`ēə kō`lī), common bacterium that normally inhabits the intestinal tracts of humans and animals, but can cause infection in other parts of the body, especially the urinary tract. C600 in the liquid mating-out assay (3,12). All transconjugants showed decreased susceptibilities to the 4 ESCs tested (MICs 16-64 [micro]g/mL) and cefoxitin (MIC 64-128 [micro]g/mL) and were susceptible to all non-[beta]-lactam agents tested. A pI 9.0 vz [beta]-lactamase and [bla.sub.CMY-2] were detected by isoelectric focusing and PCR assays, respectively, in all transconjugants. Restricted by the endonuclease endonuclease /en·do·nu·cle·ase/ (-noo´kle-as) any nuclease specifically catalyzing the hydrolysis of interior bonds of ribonucleotide or deoxyribonucleotide chains. EcoRI, the 18 transferred plasmids produced 9 major restriction patterns (Figure 1 and Table 2). Patterns E and I were further divided into 4 and 2 subtypes, respectively, [bla.sub.CMY-2] on the transferred plasmids was demonstrated by Southern hybridization hybridization /hy·brid·iza·tion/ (hi?brid-i-za´shun) 1. crossbreeding; the act or process of producing hybrids. 2. molecular hybridization 3. with the [bla.sub.CMY-2] probe. [FIGURE 1 OMITTED] The 38 ciprofloxacin-resistant S. Choleraesuis isolates were genotyped by pulsed-field gel electrophoresis gel electrophoresis n. Electrophoresis performed in a gel composed of agarose, polyacrylamide, or starch. on a CHEF Mapper apparatus (Bio-Rad Laboratories, Hercules, CA, USA) according to the PulseNet protocol (13). Banding patterns generated by XbaI restriction were compared with BioNumerics software (Applied Maths, Kortrijk, Belgium). The 38 isolates showed a close relationship (Dice correlation coefficient Correlation Coefficient A measure that determines the degree to which two variable's movements are associated. The correlation coefficient is calculated as: of 90%) and had only 1 pulsotype, based on Tenover criteria (Figure 2) (14). The pulsotype was divided into 7 pulsosubtypes, among which were 1-4 band differences. Five ESC-resistant isolates displayed the same pulsosubtypes (IA or IC) as ESC-susceptible isolates (Table 1 and Figure 2). [FIGURE 2 OMITTED] Conclusions We describe the prevalence of resistance to ciprofloxacin and ESCs among salmonellae isolated from January to May 2004 in Taiwan. We found widespread resistance of Salmonella isolates to both ESCs and ciprofloxacin; high prevalence of resistance to ciprofloxacin, ESCs, and both in S. Choleraesuis; and widespread prevalence of CMY-2 producing Salmonella isolates of various serotypes in Taiwan. The prevalence of Salmonella isolates resistant to both ceftriaxone and ciprofloxacin may pose a therapeutic problem. CMY-2 is one of the AmpC enzymes, which are usually less active against cefepime and cefpirome than ESBLs (15). Accordingly, we have used cefepime to successfully treat several patients infected in·fect tr.v. in·fect·ed, in·fect·ing, in·fects 1. To contaminate with a pathogenic microorganism or agent. 2. To communicate a pathogen or disease to. 3. To invade and produce infection in. with CMY-2-producing and ciprofloxacin-resistant S. Choleraesuis (8). Therefore, AmpC-producing strains should be differentiated from ESBL-producing strains by phenotypic phe·no·type n. 1. a. The observable physical or biochemical characteristics of an organism, as determined by both genetic makeup and environmental influences. b. or genotypic genotypic emanating from or pertaining to genotype. genotypic selection selection of breeding stock on the basis of known inherited characteristics. methods when ESC-resistant Salmonella strains are isolated in the clinical microbiology Clinical microbiology The adaptation of microbiological techniques to the study of the etiological agents of infectious disease. Clinical microbiologists determine the nature of infectious disease and test the ability of various antibiotics to inhibit or kill laboratory (15). The ciprofloxacin-resistant rate in S. Choleraesuis in Taiwan has been >60% since 2001; the high prevalence was mainly due to clonal clonal referring to a clone. clonal expansion occurs, for example, when B cells, under the influence of T cell interleukins, differentiate into two separate populations and, after several transformations produce sensitized B spread of resistant strains (4-6). The ciprofloxacin-resistant rate in S. Choleraesuis in this report (84.4%) was higher than those reported previously ([less than or equal to] 70%) (4-6). [bla.sub.CMY-2] in Salmonella in Taiwan was first reported in 2 S. Typhimurium strains isolated in 2000 (3). The first reported S. Choleraesuis strain with [bla.sub.CMY-2] was a ciprofloxacin-resistant strain isolated in 2002 (7). All our 38 ciprofloxacin-resistant S. Choleraesuis isolates, including 8 ESC-resistant isolates, were genetically related. Moreover, we found possibly unrelated [bla.sub.CMY-2]-positive plasmids (lanes 3, 4, 7, 8, 10, and 11 in Figure 1) among closely related isolates (Figure 2). These data together suggest that the development and rapidly increasing prevalence of ESC and ciprofloxacin resistance in S. Choleraesuis in Taiwan might result from the extremely high prevalence of ciprofloxacin resistance followed by the horizontal transfer of [bla.sub.CMY-2] into ciprofloxacin-resistant epidemic strains rather than from the spread of a clone clone, group of organisms, all of which are descended from a single individual through asexual reproduction, as in a pure cell culture of bacteria. Except for changes in the hereditary material that come about by mutation, all members of a clone are genetically that had been resistant to ciprofloxacin and ESCs. All our ciprofloxacin-resistant Salmonella isolates tested had mutations in the QRDRs of gyrA and par, a finding consistent with previously reported results (1,4,5). The rates of ciprofloxacin resistance in the 3 most common serotypes, Enteritidis, Typhimurium, and Stanley, remained very low (0%-0.6%). Six of 11 ciprofloxacin-resistant isolates in the group of uncommon serotypes belonged to serotype Schwarzengrund and accounted for 42.9% of all serotype Schwarzengrund isolates. Thus, the high rate (5.5%) of ciprofloxacin resistance in this group was in part due to the high prevalence of ciprofloxacin resistance in serotype Schwarzengrund.
Table 1. Resistance to ciprofloxacin, extended-spectrum
cephalosporins, and both in Salmonella enterica serotypes,
by region and pulsotype, Taiwan, January-May 2004
No. of resistant S. enterica
isolates/no. of total isolates (%)
Resistance and
region * Enteritidis Typhimurium Stanley
Ciprofloxacin 1/161 (0.6) 0/142 (0) 0/53 (0)
resistance
Northern 0/96 (0) 0/38 (0) 0/14 (0)
Central 1/32 (3.1) 0/34 (0) 0/14 (0)
Southern 0/25 (0) 0/60 (0) 0/24 (0)
Eastern 0/8 (0) 0/10 (0) 0/1 (0)
ESC resistance 0/161 (0) 0/142 (0) 3/53 (5.7)
Northern 0/96 (0) 0/38 (0) 1/14 (7.1)
Central 0/32 (0) 0/34 (0) 1/14 (7.1)
Southern 0/25 (0) 0/60 (0) 1/24 (4.2)
Eastern 0/8 (0) 0/10 (0) 0/1 (0)
Ciprofloxacin and 0/161 (0) 0/142 (0) 0/53 (0)
ESC resistance
Northern 0/96 (0) 0/38 (0) 0/14 (0)
Central 0/32 (0) 0/34 (0) 0/14 (0)
Southern 0/25 (0) 0/60 (0) 0/24 (0)
Eastern 0/8 (0) 0/10 (0) 0/1 (0)
No. of resistant S. enterica
isolates/no. of total isolates (%)
Uncommon
Resistance and serotypes All
region * Choleraesuis ([dagger]) serotypes
Ciprofloxacin 38/45 (84.4) 11/199 (5.5) 50/600 (8.3)
resistance
Northern 13/16 (81.3) 6/88 (6.8) 19/252 (7.5)
Central 6/8 (75.0) 4/37 (10.8) 11/125 (8.8)
Southern 18/20 (90.0) 1/65 (1.5) 19/194 (9.8)
Eastern 1/1 (100) 0/9 (0) 1/29 (3.4)
ESC resistance 8/45 (17.8) 9/199 (4.5) 20/600 (3.3)
Northern 1/16 (6.3) 7/88 (8.0) 9/252 (3.6)
Central 0/8 (0) 1/37 (2.7) 2/125 (0.8)
Southern 7/20 (35.0) 1/65 (1.5) 9/194 (4.6)
Eastern 0/1 (0) 0/9 (0) 0/29 (0)
Ciprofloxacin and 8/45 (17.8) 2/199 (1.0) 10/600 (1.7)
ESC resistance
Northern 1/16 (6.3) 1/88 (1.1) 2/252 (0.8)
Central 0/8 (0) 1/37 (2.7) 1/125 (0.8)
Southern 7/20 (35.0) 0/65 (0) 7/194 (3.6)
Eastern 0/1 (0) 0/9 (0) 0/29 (0)
Pulsotypes of
Resistance and Choleraesuis isolates
region * (no of isolates)
Ciprofloxacin
resistance
Northern A (11), D (1), E (1)
Central A (5), C (1)
Southern A (14), B (1), C (1), F (1), G (1)
Eastern A (1)
ESC resistance
Northern
Central
Southern
Eastern
Ciprofloxacin and
ESC resistance
Northern E (1)
Central
Southern A (4), C (1), F (1), G (1)
Eastern
* ESC, extended-spectrum cephalosporin.
([dagger]) Includes 197 isolates of 42 uncommon serotypes and 2
untypeable isolates.
Table 2. Characteristics of 20 Salmonella isolates resistant to
extended-spectrum cephalosporins
gyrA at
position
([dagger])
Specimen Resistance 83 (TCC
Serotype type pl (s) pattern * [Ser])
Albany Urine 9.0 Am ESC Fx Cm Na --
Sxt Tc ([dagger])
Cairo Stool 9.0, 5.4 Am ESC Fx Cm Na TTC (Phe)
Gm Km Sxt Tc
([dagger])
Urine 9.0 Am ESC Fx Cm Cp TTC (Phe)
Na Sxt Tc
Chester Stool 9.0 Am ESC Fx --
Choleraesuis Wound 9.0, 5.4 Am ESC Fx Cm Cp TTC (Phe)
Na Gm Km Sxt Tc
Blood 9.0, 5.4 Am ESC Fx Cm Cp TTC (Phe)
Na Gm Tc
Blood 9.0, 5.4 Am ESC Fx Cm Cp TTC (Phe)
Na Gm Km Sxt Tc
Blood 9.0, 5.4 Am ESC Fx Cm Cp TTC (Phe)
Na Gm Km Sxt
Joint 9.0, 5.4 Am ESC Fx Cm Cp TTC (Phe)
fluid Na Gm Km Sxt Tc
Kaduna Tissue 9.0, 5.4 Am ESC Fx Cm Cp TTC (Phe)
Na Sxt Tc
Saintpaul Stool 9.0 Am ESC Fx Gm --
Stanley Stool 9.0, 5.4 Am ESC Fx --
Cm Sxt Tc
Stool 9.0 Am ESC Fx --
Cm Sxt Tc
gyrA at
position
([dagger])
Isolate
(restriction
parC at pattern of
position 80 transferred
(AGC [Ser]) [bla.sub.CMY-2]+
Specimen 87 (GAC ([double plasmid)
Serotype type [Asp]) dagger]) ([section])
Albany Urine AAC (Asn) -- SA04.028 (C)
Cairo Stool -- -- NC04.001 (H1),
NC04.002 (H1),
NC04.003 (H1)
Urine GGC (Gly) AAC (Arg) NC04.004 (H2)
Chester Stool -- -- NG04.016 (G)
Choleraesuis Wound AAC (Asn) ATC (Ile) NL04.050 (B)
Blood AAC (Asn) ATC (Ile) SB04.003 (A)
Blood AAC (Asn) ATC (Ile) SE04.005 (F),
SG04.060
Blood AAC (Asn) ATC (Ile) SG04.039 (E1),
SG04.086
Joint AAC (Asn) ATC (Ile) SG04.042 (E2),
fluid SG04.047 (E4)
Kaduna Tissue AAC (Asn) ATC (Ile) CE04.015 (I)
Saintpaul Stool -- -- NG04.011 (G),
NG04.018 (G)
Stanley Stool -- -- CG04.039 (D)
Stool -- -- NB04.022 (A),
SE04.006 (E3)
* Am, ampicillin; ESC, extended-spectrum cephalosporins, Fx,
cefoxitin, Cm, chloramphenicol, Cp, ciprofloxacin; Na, nalidixic acid;
Gm, gentamicin, Km, kanamycin, Sxt, trimethoprim-sulfamethoxazole; Tc,
tetracycline.
([dagger]) The S. Albany isolate and the 3 S. Cairo isolates showed
decreased susceptibilities to ciprofloxacin (MIC 0.25-1 [micro]g/mL).
([double dagger]) Nucleotide and amino acid changes at the QRDRs of
gyrA and parC. --, no alterations in the genes.
([section]) For each isolate, the first letter indicates region (C,
central region; N, northern region, S, southern region), and the
second letter represents hospital. Isolates NC04.001, NC04.002, and
NC04.003 were from the same patients; all other isolates were from
different patients.
This work was partly supported by a research grant NSC NSC abbr. National Security Council Noun 1. NSC - a committee in the executive branch of government that advises the president on foreign and military and national security; supervises the Central Intelligence Agency 93-2320-B-006-016 from the National Science Council, Taiwan. References (1.) Su LH, Chiu CH, Chu C, Ou JT. Antimicrobial antimicrobial /an·ti·mi·cro·bi·al/ (-mi-kro´be-al) 1. killing microorganisms or suppressing their multiplication or growth. 2. an agent with such effects. resistance in nontyphoid Salmonella serotypes: a global challenge. Clin Infect infect /in·fect/ (in-fekt´) 1. to invade and produce infection in. 2. to transmit a pathogen or disease to. in·fect v. 1. Dis. 2004;39:546-51. (2.) Winokur PL, Brueggemann A, Desalvo DL, Hoffmann L. Apley MD, Uhlenhopp EK, et al. Animal and human multidrug-resistant, cephalosporin-resistant Salmonella isolates expressing a plasmid-mediated CMY-2 AmpC [beta]-lactamase. Antimicrob Agents Chemother. 2000;44:2777-83. (3.) Yan JJ, Ko WC, Chiu CH, Tsai SH, Wu HM, Wu JJ. Emergence of ceftriaxone-resistant Salmonella isolates and the rapid spread of plasmid-encoded CMY-2-like cephalosporinase, Taiwan. Emerg Infect Dis. 2003;9:323-8. (4.) Chiu CH, Wu TL, Su LH, Chu C, Chia JH, Kuo AJ, et al. The emergence in Taiwan of fluoroquinolone fluoroquinolone /flu·o·ro·quin·o·lone/ (-kwin´o-lon) any of a subgroup of fluorine-substituted quinolones, having a broader spectrum of activity than nalidixic acid. fluor·o·quin·o·lone n. resistance in Salmonella enterica serotype Choleraesuis. N Engl J Med. 2002:346:413-9. (5.) Hsueh PR, Teng LJ, Tseng SP, Chang CF, Wan JH, Yan JJ, et al. Ciprofloxacin-resistant Salmonella enterica Typhimurium and Choleraesuis from pigs to humans. Taiwan. Emerg Infect Dis. 2004;10:60-8. (6.) Chin CH, Wu TL, Su LH, Liu JW, Chu C. Fluoroquinolone resistance in Salmonella enterica serotype Choleraesuis, Taiwan, 2000-2003. Emerg Infect Dis. 2004;10:1674-6. (7.) Chiu CH, Su LH, Chu C, Chia JH, Wu TI, Lin TY, et al. Isolation of Salmonella enterica serotype Choleraesuis resistant to ceftriaxone and ciprofloxacin. Lancet lancet /lan·cet/ (lan´set) a small, pointed, two-edged surgical knife. lan·cet n. . 2004;363:1285-6. (8.) Ko WC, Yan JJ, Yu WL, Lee HC, Lee NY, Wang LR, et al. A new therapeutic challenge for old pathogens: invasive community-acquired infections caused by ceftriaxone- and ciprofloxacin-resistant Salmonella enterica serotype Choleraesuis. Clin Infect Dis. 2005;40:315-8. (9.) NCCLS NCCLS National Committee for Clinical Laboratory Standards . Methods for dilution antimicrobial susceptibility tests susceptibility test Antimicrobial susceptibility test, see there for bacteria that grow aerobically; approved standard. 6th ed. M7-A6. Wayne (PA): The Committee; 2003. (10.) Jarlier V, Nicolas MH, Fournier G, Philippon A. Extended broad-spectrum [beta]-lactamases conferring transferable resistance to newer [beta]-lactam agents in Enterobacteriaceae: hospital prevalence and susceptibility patterns. Rev Infect Dis. 1988;10:867-78. (11.) Matthew M, Harris M, Marshall MJ, Rose GW. The use of analytical isoelectric focusing for detection and identification of [beta]-lactamases. J Gen Microbiol. 1975;88:169-78. (12.) Provence DL, Curtiss R III. Gene transfer in gram-negative bacteria. In: Gerhardt P, Murray RGE RGE Range (surveys) RGE Rochester Gas and Electric RGE Resume Generating Event RGE Real Good Edition , Wood WA, Krieg NR, editors. Methods for general and molecular bacteriology bacteriology Study of bacteria. Modern understanding of bacterial forms dates from Ferdinand Cohn's classifications. Other researchers, such as Louis Pasteur, established the connection between bacteria and fermentation and disease. . Washington: American Society for Microbiology The American Society for Microbiology (ASM) is a scientific organization, based in the United States although with over 43,000 members throughout the world. It is the largest single life science professional organization and its members include those whose interests encompass basic ; 1994. p. 319-47. (13.) Graves LM, Swaminathan B. PulseNet standardized standardized pertaining to data that have been submitted to standardization procedures. standardized morbidity rate see morbidity rate. standardized mortality rate see mortality rate. protocol for sub-typing Listeria Listeria /Lis·te·ria/ (lis-ter´e-ah) a genus of gram-negative bacteria (family Corynebacterium); L. monocyto´genes causes listeriosis. Lis·te·ri·a n. monocytogenes by macrorestriction and pulsed-field gel electrophoresis. Int J Food Microbiol. 2001;65:55-62. (14.) Tenover FC, Arbeit R, Goering RV, Mickelsen PA, Murray BE, Persing DH, et al. Interpreting chromosomal chromosomal, adj relating to chromosome, or a configuration within the cell's nucleus that contains a linear thread of DNA that conveys genetic data. chromosomal emanating from or pertaining to chromosome. DNA DNA: see nucleic acid. DNA or deoxyribonucleic acid One of two types of nucleic acid (the other is RNA); a complex organic compound found in all living cells and many viruses. It is the chemical substance of genes. restriction patterns produced by pulsed-field gel electrophoresis: criteria for bacterial strain typing. J Clin Microbiol. 1995;33:2233-9. (15.) Philippon A, Arlet G, Jacoby GA. Plasmid-determined AmpC-type [beta]-lactamases. Antimicrob Agents Chemother. 2002;46:1-11. Jing-Jou Yan, * Chien-Shun Chiou, ([dagger]) Tsai-Ling Yang Lauderdale, ([double dagger double dagger n. A reference mark (  ) used in printing and writing. Also called diesis.Noun 1. ]) Shu-Huei Tsai, * and Jiunn-Jong Wu * * National Cheng Kung University National Cheng Kung University (Traditional Chinese: 國立成功大學; Simplified Chinese: 国立成功大学 College of Medicine, Tainan, Taiwan; ([dagger]) Center for Disease Control, Taichung City, Taiwan; and ([double dagger]) National Health Research Institutes, Taipei, Taiwan Dr. Yan is an associate professor, Department of Pathology, National Cheng Kung University College of Medicine, Tainan, Taiwan. His major research interests are the epidemiology and mechanisms of antimicrobial resistance, especially [beta]-lactamases in gram-negative bacteria. Address for correspondence: Jiunn-Jong Wu, Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, No. 1 University Rd, Tainan, Taiwan 70101; fax: 886-6-236-3956: email: jjwu@mail.ncku.edu.tw |
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