Antibiotic resistance of gram-negative bacteria in rivers, United States.Bacteria with intrinsic resistance to antibiotics are found in nature. Such organisms may acquire additional resistance genes from bacteria introduced into soil or water, and the resident bacteria may be the reservoir or source of widespread resistant organisms found in many environments. We isolated antibiotic-resistant bacteria in freshwater samples from 16 U.S. rivers at 22 sites and measured the prevalence of organisms resistant to [beta]-lactam and non-[beta]-lactam antibiotics. Over 40% of the bacteria resistant to more than one antibiotic had at least one plasmid. Ampicillin ampicillin (ăm'pĭsĭl`ĭn), a penicillin-type antibiotic that is effective against both gram-negative microorganisms and gram-positive microorganisms such as Escherichia coli. resistance genes, as well as other resistance traits, were identified in 70% of the plasmids. The most common resistant organisms belonged to the following genera: Acinetobacter, Alcaligenes, Citrobacter, Enterobacter, Pseudomonas Pseudomonas A genus of gram-negative, nonsporeforming, rod-shaped bacteria. Motile species possess polar flagella. They are strictly aerobic, but some members do respire anaerobically in the presence of nitrate. , and Serratia. ********** The presence of antibiotic-resistant bacteria in freshwater sources throughout the world has been documented (1-5). Selection of resistant organisms in nature may result from natural production of antibiotics The production of antibiotics has been widespread since the pioneering efforts of Florey and Chain in 1939. The importance of antibiotics to medicine has led to much research into discovering and producing them. by soil organisms, runoff from animal feed or crops, or waste products from treated animals or humans (6-10). Natural reservoirs of resistance genes may provide a source of transferable traits for emerging pathogens (6,11). The prevalence, nature, properties, and origin of such reservoirs in U.S. rivers have not been studied on a national scale. We frequently found organisms resistant to naturally occurring and human-modified antibiotics in U.S. rivers. A large proportion of the resistant organisms were found to contain plasmids with resistance traits. Methods Sterile pipettes were used to collect triplicate 10-mL water samples at each site. Samples were collected in city limits at all locations; sites were usually 1 mile downstream of the downtown area. Each sample was collected at a depth of approximately 15 cm. Temperature and pH measurements were also made at the time of sampling. All samples, either undiluted or diluted in Luria-Bertani (LB) broth (12), were plated (0.1 mL, spread plate) on LB agar, some with and some without ampicillin (150 [micro]g/mL) at the collection site. Ampicillin was used to select for potential [beta]-lactamase producers. Water samples were not stored or concentrated before plating. Plates were incubated at 30[degrees]C-32[degrees]C for 24 hours Adv. 1. for 24 hours - without stopping; "she worked around the clock" around the clock, round the clock before the total number of bacteria and ampicillin-resistant bacteria were estimated. Variations in the number of CFU CFU see colony-forming units. and ampicillin-resistant CFU did not differ (p=0.01) in a group of the triplicate samples plated at a particular time. Ampicillin-resistant isolates were picked to master LB plus ampicillin plates until further tested against additional antibiotics. National Committee for Clinical Laboratory Standards (NCCLS NCCLS National Committee for Clinical Laboratory Standards ) procedures and evaluation methods were used (13). Briefly, isolates were grown in LB plus ampicillin broth until the turbidity turbidity /tur·bid·i·ty/ (ter-bid´i-te) cloudiness; disturbance of solids (sediment) in a solution, so that it is not clear.tur´bid Turbidity The cloudiness or lack of transparency of a solution. of a 0.5 MacFarland standard was reached. Cultures were swabbed on Mueller-Hinton agar, and antibiotic discs (Becton Dickinson BD (NYSE: BDX), is a medical technology company that manufactures and sells medical devices, instrument systems and reagents. Founded in 1897 and headquartered in Franklin Lakes, New Jersey, BD employs 27,000 people in nearly 50 countries. and Co., Cockeysville, MD) were added. The antibiotics used were cefotaxime, ceftazidime, amoxicillin amoxicillin /amox·i·cil·lin/ (ah-mok?si-sil´in) a semisynthetic derivative of ampicillin effective against a broad spectrum of gram-positive and gram-negative bacteria. a·mox·i·cil·lin n. plus clavulanic acid clav·u·lan·ic acid n. A drug that inhibits the action of beta-lactamase produced by bacteria, thereby counteracting bacterial resistance to beta-lactam antibiotics. , cephalothin cephalothin a first generation cephalosporin antibiotic. Sensitive organisms include many penicillin-resistant staphylococci. cephalothin Cefalotin® Infectious disease A parenteral semisynthetic derivative of cephalosporin C, and 3 , imipenem, kanamycin kanamycin /kan·a·my·cin/ (kan?ah-mi´sin) an aminoglycoside antibiotic derived from Streptomyces kanamyceticus, effective against aerobic gram-negative bacilli and some gram-positive bacteria, including mycobacteria; used as the , streptomycin streptomycin (strĕp'tōmī`sĭn), antibiotic produced by soil bacteria of the genus Streptomyces and active against both gram-positive and gram-negative bacteria (see Gram's stain), including species resistant to other , chloramphenicol chloramphenicol (klōr'ămfĕn`əkŏl'), antibiotic effective against a wide range of gram-negative and gram-positive bacteria (see Gram's stain). It was originally isolated from a species of Streptomyces bacteria. , tetracycline tetracycline (tĕ'trəsī`klēn), any of a group of antibiotics produced by bacteria of the genus Streptomyces. They are effective against a wide range of Gram positive and Gram negative bacteria, interfering with protein , and 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. . MIC were determined with E test strips (AB Biodisk North America North America, third largest continent (1990 est. pop. 365,000,000), c.9,400,000 sq mi (24,346,000 sq km), the northern of the two continents of the Western Hemisphere. , Piscataway, NJ) under NCCLS conditions as described by the manufacturer. Isolates showing complete resistance to at least one antibiotic other than ampicillin were frozen in LB plus 10% dimethyl sulfoxide dimethyl sulfoxide (DMSO) Colourless, nearly odourless liquid organic compound. It mixes in all proportions with water, ethanol, and most organic solvents and dissolves a wide variety of compounds (but not aliphatic hydrocarbons). at -78[degrees]C and used as stocks for further testing. Freezing was preferred since isolate storage in the refrigerator for >2 weeks frequently resulted in loss of cultures. Nitrocefin discs (Cefinase, BD Microbiology Systems, Sparks, MD) were placed on bacterial cultures growing on Mueller Hinton agar and observed for the color change indicative of hydrolysis hydrolysis (hīdrŏl`ĭsĭs), chemical reaction of a compound with water, usually resulting in the formation of one or more new compounds. . Organisms were grown overnight in LB with ampicillin broth with shaking. Two methods were used for every isolate examined: the boiling method (14) and alkaline lysis Alkaline lysis is a method used in molecular biology to isolate plasmid DNA from bacterial cells. Bacteria containing the plasmid of interest is first grown, then lysed with a strong alkaline solution made from sodium dodecyl sulfate (SDS) and sodium hydroxide. (15). Agarose gel electrophoresis Agarose gel electrophoresis is a method used in biochemistry and molecular biology to separate DNA, RNA, or protein molecules by size. This is achieved by moving negatively charged nucleic acid molecules through an agarose matrix with an electric field (electrophoresis). in 0.7% agarose agarose more highly purified form of agar with similar uses to agar and widely used in the separation of nucleic acid fragments. (GTG (chat) gtg - Got to go. The user is about to stop chatting. , FMC See fixed mobile convergence. Corp., Rockland, ME) with 1X Tris/acetate/EDTA buffer (12) was used to determine the presence and size of plasmids. Plasmids were purified by removal of unstained gel slices and centrifugal elution elution /elu·tion/ (e-loo´shun) in chemistry, separation of material by washing; the process of pulverizing substances and mixing them with water in order to separate the heavier constituents, which settle out in solution, from the through polyester fiberfill fi·ber·fill n. Lightweight synthetic fiber used as filling or insulation, as in comforters, pillows, and outerwear. plugs (16). The presence of resistance markers on purified plasmids was determined as follows: electrocompetent 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. (TOP 10 cells, Invitrogen, Inc., Carlsbad, CA) was mixed with 5 gL of pure plasmid DNA Noun 1. plasmid DNA - a small cellular inclusion consisting of a ring of DNA that is not in a chromosome but is capable of autonomous replication plasmid and subjected to 1.8 kV in a Bio-Rad Pulser (Bio-Rad Laboratories, Hercules, CA). Electroporated cells (cells with 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. physically introduced) were mixed with SOC medium SOC medium is a nutritionally rich bacterial growth medium, perhaps the second-most widely used medium for culture of Escherichia coli in molecular biology, the most widely used being lysogeny broth, or LB. (12) and incubated for 60 minutes at 37[degrees]C before plating on LB with ampicillin plates. Transformants were picked and checked for additional resistance traits as described above. Results The number and range of ampicillin-resistant bacteria recovered at the 22 sites sampled in the past 3 years are shown in Table 1. Fourteen of the rivers were sampled more than once. Considerable variations in the total number of CFU and ampicillin-resistant organisms were encountered. The MIC for ampicillin was >256 for 98% of the ampicillin-resistant organisms tested. This high level of resistance, found in all rivers tested, was not unexpected since initial plating was on LB plates containing 150 [micro]g/mL of the antibiotic. No apparent correlation existed between numbers of culturable or ampicillin-resistant organisms and temperature (range 0[degrees]C-28[degrees]C) or pH (range 7.2-8.7) in any of the rivers tested (data not shown). The number of resistant isolates growing on MacConkey agar MacConkey (also McConkey) agar is a culture medium designed to grow Gram-negative bacteria and stain them for lactose fermentation. It contains bile salts, crystal violet dye (to inhibit Gram-positive bacteria), neutral red dye (which stains microbes fermenting lactose), was >90% for most samples. The ampicillin-resistant isolates were predominantly gram-negative nonlactose-fermenters (data not shown). Oxidase testing and biochemical characterization indicated that the major genera of these bacteria were Acinetobacter, Alcaligenes, Citrobacter, Enterobacter, Pseudomonas, and Serratia. Klebsiella klebsiella Any of the rod-shaped bacteria that make up the genus Klebsiella. They are gram-negative (see gram stain), thrive better without oxygen than with it, and do not move. K. and Proteus were also isolated but less frequently than the other organisms. The resistance of ampicillin-resistant isolates to other [beta]-lactam antibiotics is presented in Table 2. Organisms resistant to cefotaxime, ceftazidime, and imipenem were detected at a number of sites. This finding prompted us to plate water samples on LB medium with cefotaxime (60 [micro]g/mL). Cefotaxime-resistant bacteria were readily isolated from all rivers tested on this selective medium (Table 3). Of these cefotaxime-resistant organisms, 20% to 30% were gram-positive, spore-forming rods, which appeared to belong to the genus Bacillus Noun 1. genus Bacillus - type genus of the Bacillaceae; includes many saprophytes important in decay of organic matter and a number of parasites B, bacillus - aerobic rod-shaped spore-producing bacterium; often occurring in chainlike formations; found primarily in . Although these gram-positive organisms may be important as reservoirs of resistance genes, only those cefotaxime-resistant isolates growing on MacConkey agar and shown to be gram negative were used for further analysis. Of the gram-negative cefotaxime-resistant organisms, 87% had a cefotaxime MIC >256. The remaining 13% had an MIC >48. Every cefotaxime-resistant isolate was capable of hydrolyzing nitrocefin, indicating the presence of [beta]-lactamase. Many of the cefotaxime-resistant isolates were also resistant to ceftazidime (Table 4). Sixty-one per cent of the ceftazidime-resistant organisms (71 isolates tested) had a ceftazidime MIC >256, while 17% had an MIC of 12 to 192. Most (>80%) of the cefotaxime-resistant and ceftazidime-resistant organisms were identified as Pseudomonas. The resistance of ampicillin-resistant isolates to non-[beta]-lactam antibiotics is shown in Table 5. Many organisms in the rivers had resistance to at least one antibiotic other than ampicillin, and a substantial fraction were able to survive a number of antibiotics. One gram-negative organism resistant to ciprofloxacin was found in the 3,011 ampicillin-resistant isolates tested. Gram-positive ciprofloxacin-resistant bacteria were more numerous and were readily isolated. Two different plasmid isolation procedures were used to analyze the isolates resistant to ampicillin and one other antibiotic. Of the 374 isolates, 167 (44%) contained at least one plasmid. This number probably represents a minimal estimate since the methods used may not be optimal for all species encountered. Plasmids ranged in size from 2 kb to >23 kb. Purified plasmids were checked for their ability to transform E. coli E. coli: see Escherichia coli. E. coli in full Escherichia coli Species of bacterium that inhabits the stomach and intestines. E. coli can be transmitted by water, milk, food, or flies and other insects. . Of the 54 plasmids tested, 38 (70%) contained the gene for ampicillin resistance. Further, 97% of the plasmids with the ampicillin-resistant gene also carried at least one other resistance trait. Discussion We found that culturable antibiotic-resistant bacteria were widespread in nonconcentrated water samples from many U.S. rivers. This finding, in and of itself, is not surprising since the intrinsic resistance of many organisms to antibiotics is well documented (17). Bacteria that are resistant to chemically modified and synthesized antibiotics are also widespread in the environment. The use of selective media resulted in the isolation of gram-negative organisms with high levels of resistance (MIC [greater than or equal to]256 [micro]g) to the clinically useful [beta]-lactams ampicillin, cefotaxime, and ceftazidime. Organisms resistant to imipenem were also frequently isolated. Nitrocefin hydrolysis data suggest that [beta]-lactamase production is a major mechanism of resistance to ampicillin in river isolates. The resistance of natural isolates to cefiazidime and cefotaxime strongly suggests that these organisms may produce extended-spectrum [beta]-lactamases (ESBL ESBL Extended Spectrum Beta Lactamase ESBL East Staffordshire Badminton League (UK) ), since resistance to these third-generation 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 is considered the single most important indicator of ESBL (18,19). Alternatively, chromosomal AmpC [beta]-lactamases may be responsible for the resistance of Pseudomonas to cefotaxine and cefiazidime (19). Distinguishing between these possibilities will be important in determining transmissibility trans·mis·si·ble adj. That can be transmitted: transmissible signals. trans·mis of [beta]-lactamase resistance. Many of the organisms resistant to ampicillin and at least one other antibiotic (40%) harbored plasmids. Although two methods were used to isolate plasmids, some bacteria may have been refractory to these procedures or a large or low copy number plasmids were not observed. Resistance to ampicillin and other antibiotics was plasmid-borne, as indicated by electroporation electroporation (i·lekˈ·trō·p  ·rāˑ·sh of cells with purified plasmids.The results presented here have limitations and must be considered in light of the fact that many aquatic organisms are probably nonculturable (20). The bacteria that cannot be cultivated may be part of the reservoir of resistance genes as well. PCR PCR polymerase chain reaction. PCR abbr. polymerase chain reaction Polymerase chain reaction (PCR) has been used to identify nonculturable bacteria in stream sediments (21). This technique may be used to identify antibiotic resistance antibiotic resistance, n the ability of certain strains of microorganisms to develop resistance to antibiotics. antibiotic resistance genes in nonculturable organisms as well. Many of the ampicillin-resistant isolates were also resistant to non-[beta]-lactam antibiotics (Table 5). The frequency with which these organisms were found suggests that characterization of resistance genes and the plasmids on which they reside should provide information about reservoirs for antibiotic resistance in the environment.
Table 1. Ampicillin-resistant bacteria, U.S. rivers
River N (a) [log.sub.10] CFU/mL (b)
Arkansas-Little Rock, AR 2 3.09-3.37 (3.25)
Arkansas-Wichita, KS 4 3.09-4.05 (3.66)
Canadian-Oklahoma City, OK 2 3.03-4.36 (4.08)
Chattahoochee-Atlanta, GA 2 2.32-2.66 (2.52)
Chicago-Chicago, IL 1 4.21
Colorado-Glenwood Springs, CO 1 2.56
Cuyahoga-Cleveland, OH 1 3.45
Des Moines-Des Moines, IA 3 2.66-3.81 (3.40)
Hudson-New York, NY 3 2.94-4.06 (3.80)
Kansas-Topeka, KS 24 2.86-4.15 (3.67)
Mississippi-New Orleans, LA 1 3.09
Mississippi-Minneapolis, MN 2 2.89-3.22 (3.09)
Mississippi-St. Louis, MO 4 3.93-4.61 (4.31)
Missouri-Parkville, MO 7 3.28-4.70 (4.08)
Ohio-Cincinnati, OH 6 2.86-4.80 (4.15)
Ohio-Louisville, KY 4 2.59-3.70 (3.22)
Ohio-Pittsburgh, PA 1 2.53
Ohio-Wheeling, WV 1 2.76
Platte-Grand Island, NE 3 3.20-3.56 (3.32)
Scioto-Columbus, OH 1 2.80
Wabash-Terre Haute, IN 3 2.81-3.19 (3.04)
White-Indianapolis, IN 1 4.36
% ampicillin
River -resistant
Arkansas-Little Rock, AR 6.6-21.0
Arkansas-Wichita, KS 10.4-25.7
Canadian-Oklahoma City, OK 22.6-24.1
Chattahoochee-Atlanta, GA 34.5-38.4
Chicago-Chicago, IL 26.9
Colorado-Glenwood Springs, CO 59.2
Cuyahoga-Cleveland, OH 26.4
Des Moines-Des Moines, IA 13.7-34
Hudson-New York, NY 10.1-36.6
Kansas-Topeka, KS 4.9-52.5
Mississippi-New Orleans, LA 5.9
Mississippi-Minneapolis, MN 19.7-23.7
Mississippi-St. Louis, MO 6.7-73.0
Missouri-Parkville, MO 6.1-21.5
Ohio-Cincinnati, OH 20.0-53.0
Ohio-Louisville, KY 12.4-20.0
Ohio-Pittsburgh, PA 15.7
Ohio-Wheeling, WV 32.0
Platte-Grand Island, NE 3.5-33.9
Scioto-Columbus, OH 3.9
Wabash-Terre Haute, IN 17.0-25.0
White-Indianapolis, IN 22.5
(a) Refers to the number of visits to each site.
(b) Total CFU isolated on Luria-Bertani medium; range and mean
(in parentheses) are given for sites sampled more than once.
Table 2. Resistance of ampicillin-resistant isolates to other
[beta]-lactam antibiotics, U.S. rivers (a)
% resistant
No.
River Tested CEF CTX CAZ IPM AMC
Arkansas-Wichita, KS 43 -- (a) 5 2 5 --
Canadian-Oklahoma City, OK 50 -- 6 0 0 --
Chattahoochee-Atlanta, GA 70 93 13 -- -- --
Chicago-Chicago, IL 81 96 9 0 0 --
Colorado-Glenwood Springs, CO 87 94 25 1 10 --
Cuyahoga-Cleveland, OH 79 91 12 6 0 68
Des Moines-Des Moines, IA 63 8 0 0 0 8
Hudson-New York, NY 107 86 9 0 -- --
Kansas-Topeka, KS 199 25 20 8 4 --
Missouri-Parkville, MO 203 73 21 5 1 --
Ohio-Louisville, KY 85 67 4 2 0 l0
Ohio-Cincinnati, OH 91 77 0 0 0 37
Ohio-Pittsburgh, PA 54 78 8 9 -- 36
Ohio-Wheeling, WV 50 36 0 0 6 0
Platte-Grand Island, NE 245 96 16 2 -- 24
Scioto-Columbus, OH 67 86 2 0 -- 33
Mississippi-Minneapolis, MN 72 38 0 0 0 38
Mississippi-St. Louis, MO 51 98 4 0 -- 57
Wabash-Terre Haute, IN 81 94 7 0 0 --
White-Indianapolis, IN 83 96 39 -- -- --
(a) Abbreviations used: --,not tested; CEF, cephalothin; CTX,
cefotaxime; CAZ, ceftazidime; IPM, imipenem; AMC,
amoxicillin+clavalanic acid.
Table 3. Isolation of cefotaxime-resistant bacteria, U.S. rivers
log CFU/mL (%)
River LB (a) LB+ampicillin LB+ cefotaxime
Arkansas-Wichita, KS 3.24 2.65 (25.7) 1.50 (1.8)
Canadian-Oklahoma City, OK 4.36 3.74 (24.1) 2.72 (2.3)
Chicago-Chicago, IL 4.21 3.64 (26.9) 2.37 (1.4)
Des Moines-Des Moines, IA 3.81 2.95 (13.7) 2.09 (1.9)
Hudson-New York, NY 2.94 2.46 (32.8) 1.65 (5.1)
Kansas-Topeka, KS 4.49 4.21 (52.5) 3.23 (5.5)
Mississippi-St. Louis, MO 3.99 3.29 (20.1) 2.51 (3.3)
Missouri-Parkville, MO 4.70 3.96 (18.2) 3.29 (3.9)
Ohio-Louisville, KY 2.70 1.86 (14.4) 0.60 (0.8)
Ohio-Cincinnati, OH 2.89 2.20 (20.0) 0.48 (0.3)
Platte-Grand Island, NE 4.23 3.45 (16.7) 2.74 (3.2)
Wabash-Terre Haute, IN 3.19 2.59 (25.0) 1.75 (3.7)
(a) LB, Luria-Bertani broth.
Table 4. Cefotaxime-resistant isolates, U.S. rivers
River Ceftazidime-resistant/total tested (%)
Canadian-Oklahoma City, OK 16/50 (32.0)
Chicago-Chicago, IL 14/32 (43.7)
Des Moines-Des Moines, IA 19/28 (67.8)
Kansas-Topeka, KS 15/28 (53.5)
Mississippi-St. Louis, MO 41/43 (95.3)
Missouri-Parkville, MO 28/49 (57.1)
Platte-Grand Island, NE 12/73 (16.4)
Table 5. Resistance of ampicillin-resistant isolates to
non-[beta]--lactam antibiotics (a)
Ampicillin-resistant
isolates
No. Ampicillin
River tested + 1 (%)
Arkansas-Little Rock, AR 80 3 (3.7) (a)
Arkansas-Wichita, KS 155 31 (20)
Canadian-Oklahoma City, OK 42 6 (14)
Chattahoochee-Atlanta, GA 101 21 (20.8)
Chicago-Chicago, IL 100 43 (43)
Colorado-Glenwood Springs, CO 100 32 (32)
Cuyahoga-Cleveland, OH 79 28 (35.4)
Des Moines-Des Moines, IA 105 50 (47.6)
Hudson-New York, NY 108 20 (18.5)
Kansas-Topeka, KS 104 44 (42.3)
Mississippi-New Orleans, LA 42 10 (23.8)
Mississippi-Minneapolis, MN 115 19 (16.5)
Mississippi-St. Louis, MO 161 46 (28.8)
Missouri-Parkville, MO 182 30 (16.4)
Ohio-Cincinnati, OH 144 16 (11.1)
Ohio-Louisville, KY 141 22 (15.6)
Ohio-Pittsburgh, PA 54 14 (25.9)
Ohio-Wheeling, WV 50 2 (4)
Platte-Grand Island, NE 65 11 (16.9)
Scioto-Columbus, OH 59 10 (16.9)
Wabash-Terre Haute, IN 109 30 (27.5)
White-Indianapolis, IN 106 17 (16)
Ampicillin-resistant
isolates
Ampicillin
No. [greater than or
River tested equal to] 1 (%)
Arkansas-Little Rock, AR 80 1 (1.2)
Arkansas-Wichita, KS 155 3 (1.9)
Canadian-Oklahoma City, OK 42 2 (4.7)
Chattahoochee-Atlanta, GA 101 2 (2.0)
Chicago-Chicago, IL 100 12 (12)
Colorado-Glenwood Springs, CO 100 24 (24)
Cuyahoga-Cleveland, OH 79 10 (12.6)
Des Moines-Des Moines, IA 105 8 (7.6)
Hudson-New York, NY 108 7 (6.5)
Kansas-Topeka, KS 104 2 (1.9)
Mississippi-New Orleans, LA 42 4 (9.5)
Mississippi-Minneapolis, MN 115 7 (6.0)
Mississippi-St. Louis, MO 161 10 (6.2)
Missouri-Parkville, MO 182 11 (6.0)
Ohio-Cincinnati, OH 144 4 (2.7)
Ohio-Louisville, KY 141 7 (4.9)
Ohio-Pittsburgh, PA 54 5 (9.2)
Ohio-Wheeling, WV 50 0 (0)
Platte-Grand Island, NE 65 3 (4.6)
Scioto-Columbus, OH 59 3 (5.0)
Wabash-Terre Haute, IN 109 12 (11)
White-Indianapolis, IN 106 5 (4.7)
(a) Ampicillin + 1 = resistance to ampicillin and at least one
non-[beta]--lactam. Ampicillin [greater than or equal to] 1
= resistance to ampicillin and 2 or more non-[beta]--lactams.
Non-[beta]--lactam antibiotics tested: ciprofloxacin, tetracycline,
chloramphenicol, kanamycin, and streptomycin.
References (1.) French GL, Ling J, Chow KL, Mark KK. Occurrence of multiple antibiotic resistance and R-plasmid in gram-negative bacteria isolated from fecally contaminated contaminated, v 1. made radioactive by the addition of small quantities of radioactive material. 2. made contaminated by adding infective or radiographic materials. 3. an infective surface or object. freshwater streams. Epidemiol Infect 1987;98:285-99. (2.) Kelch WJ, Lee JS. Antibiotic resistance patterns of gram negative bacteria isolated from environmental sources. Appl Environ Microbiol 1978;36:450-6. (3.) Niemi M, Sibakov M, Niemala S. Antibiotic resistance among different species of fecal coliforms Fecal coliforms (sometimes faecal coliforms) are facultatively-anaerobic, rod-shaped, gram-negative, non-sporulating bacteria. They are capable of growth in the presence of bile salts or similar surface agents, oxidase negative, and produce acid and gas from lactose within isolated from water samples. Appl Environ Microbiol 1983;45:79-83. (4.) Ogan MT, Nwiika DE. Studies on the ecology of aquatic bacteria on the Lower Niger delta The Niger Delta, the delta of the Niger River in Nigeria, is a densely populated region sometimes called the Oil Rivers because it was once a major producer of palm oil. : multiple antibiotic resistance among the standard plate count organisms. J Applied Bacteriol 1993;74:595-602. (5.) Young H-K H-K Hunter-Killer . Antimicrobial resistance spread in aquatic environments. J Antimicrob Chemother 1993;31:627-35. (6.) Davies J. Inactivation inactivation /in·ac·ti·va·tion/ (in-ak?ti-va´shun) the destruction of biological activity, as of a virus, by the action of heat or other agent. of antibiotics and the dissemination of resistance genes. Science 1994;264:375-82. (7.) Levy SB. Antibiotic resistance: an ecological imbalance. In: Chadwick DJ, Goode J, editors. Antibiotic resistance: origins, evolution, selection and spread. Chichester, Great Britian: Wiley and Sons; 1997. p. 1-9. (8.) Witte W. Impact of antibiotic use in animal feeding on resistance of bacterial pathogens in humans. In Chadwick DJ, Goode J, editors. Antibiotic resistance: origins, evolution, selection and spread. Chichester, Great Britian: Wiley and Sons; 1997. p.61-75. (9.) Tenover FC, McGowan JE. Reasons for the emergence of antibiotic resistance. Am J Med Sci 1996;311:9-16. (10.) Witte W. Medical consequences of antibiotic use in agriculture. Science 1998;279:996-7. (11.) van Elsas JD, Fry J, Hirsch P, Molin S. Ecology of plasmid transfer and spread. In: Thomas CM, editor. The horizontal gene pool. Amsterdam, the Netherlands: Harwood; 2000. p. 175-206. (12.) Sambrook J, Fritsch EF, Maniatis T. Molecular cloning Molecular cloning refers to the procedure of isolating a defined DNA sequence and obtaining multiple copies of it in vivo. Cloning is frequently employed to amplify DNA fragments containing genes, but it can be used to amplify any DNA sequence such as promoters, non-coding 3. New York New York, state, United States New York, Middle Atlantic state of the United States. It is bordered by Vermont, Massachusetts, Connecticut, and the Atlantic Ocean (E), New Jersey and Pennsylvania (S), Lakes Erie and Ontario and the Canadian province of : Cold Spring Harbor Press; 1989. p. A1-A2. (13.) National Committee for Clinical Laboratory Standards. Performance standards for antimicrobial disk susceptibility tests M2-A6. Wayne (PA): The Committee; 1997. (14.) Holmes DS, Quigley M. A rapid boiling method for the preparation of bacterial plasmids. Anal Biochem 1981; 114:193-7. (15.) Birnboim HC, Doly J. A rapid alkaline extraction procedure for screening recombinant plasmid DNA. Anal Biochem 1979; 114:193-7. (16.) Glenn TC, Glenn SJ. Rapid elution of DNA from agarose gels using polyester plug spin inserts (PEPSIs). Trends Genet genet: see civet. 1994; 10:344. (17.) Quintiliani R Jr, Sahm DF, Courvalin P. Mechanism of resistance to 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. . In: Murray PR, Baron EJ, Pfaller MA, Tenover FC, Yolken RH, editors. Manual of 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 . 7th ed. Washington: ASM (1) (Association for Systems Management) An international membership organization based in Cleveland, Ohio. Founded in 1947 and disbanded in 1996, it sponsored conferences in all phases of administrative systems and management. Press; 1999. p. 1505-25. (18.) Katsanis GP, Spargo J, Ferraro MJ, Sutton L, Jacoby GA. Detection of Klebsiella pneumoniae Klebsiella pneu·mo·ni·ae n. Friedlander's bacillus. and E. coli strains producing extended spectrum beta-lactamases. J Clin Microbiol 1994;32:691-6. (19.) Livermore DM. Beta-lactamases in laboratory and clinical resistance. Clin Microbiol Rev 1995;8:557-84. (20.) Roszak DB, Colwell RR. Survival strategies of bacteria in the natural environment. Microbiol Rev 1987;51:365-79. (21.) Left LG, Dana JR, McArthur JV, Shimkets LJ. Comparison of methods of DNA extraction DNA extraction is a routine procedure to collect DNA for subsequent molecular or forensic analysis. Outline of a DNA extraction There are three basic steps in a DNA extraction, the details of which may vary depending on the type of sample and any substances that may from stream sediments. Appl Environ Microbiol 1995;61:1141-3. Dr. Ash is professor of biology at Washburn University. His research interests include mechanisms of antibiotic resistance. Ronald J. Ash, * Brena Mauck, * and Melissa Morgan * * Washburn University, Topeka, Kansas, USA Address for correspondence: Ronald J. Ash, Department of Biology, Washburn University, Topeka, KS 66621, USA; fax: 785-231-1089; e-mail: zzash@washburn.edu |
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