CA2125167A1

CA2125167A1 - Method of reducing medical device related infections

Info

Publication number: CA2125167A1
Application number: CA002125167A
Authority: CA
Inventors: Bruce Farber
Original assignee: Individual
Current assignee: North Shore University Hospital Research Corp
Priority date: 1991-12-06
Filing date: 1992-12-03
Publication date: 1993-06-10
Also published as: DE69221501D1; AU667069B2; EP0615458A4; ATE156368T1; US5366505A; DE69221501T2; JPH07505131A; DK0615458T3; AU3235293A; ES2106318T3; WO1993010847A1; US5716406A; EP0615458B1; EP0615458A1

Abstract

The growth of microorganisms on catheters and other medical devices is inhibited by slime-inhibiting compounds. Slime-inhibiting compounds include salicylic acid and other NSAID.

Description

WO 93/10847 212 ~;16 7 PCI`/lLJS92/10413 METHOD OF RED C NG MEDICA~ DEVIC:E~ RELATED INFECTIONS : - ~
BAC~GROUND OF THE INVEN~TION . .~:
The frequency of infection a~sociated with the :-use of invasive medical devices such as insertable as ~: :
well as implantable de~ices i5 well documented. In the :
case of insertable devices such as catheters, the rate of infection necessitates fre~uent replacement. In the case of implantable devices such as prosthetic devices, infections in~erfere with adaptation to the device. In elther case, life-threatening sep~icemia can result from such in~ections.
The pathophysiology of medical device rela~ed infections is complex. Many factors influence the risk and type of infetion. These include factors related to the host, to the medical device and to ~he ~irulence and inoculum of the infecting organism. Hundreds of medical publicatlons have investigated and documented the variables that contribute to these factors. It has been ~.
well e~abli~hed that the overwhelming majority of medical de~ice associated infections occur when bacteria colonize and then migrate along the medical device until they gain access to the bloodstream. Accordingly, the -:
ability of bacteria to adhere to a medical device is :~
im~ortan~to the succe~sful establishment of an infection. :' The role of bacterial surface polysaccharides i~ adherence is well e~tabli~hed. Over 12 years ago a ~ :
~erie~ of experiments demonstrated the ubi~uitous n~ture : -of these polysac harides. Surface polysaccharides are found on most bacteria and fungi. When confronted with a 3peci~ic lectin, the surface polysaccharides generate a W093/l0~7 PCT/US92/10413 21251~7 glycocalyx that surrounds the bacteria and adhering surface. The glycocalyx con~ists of a mass of long polysaccharide fibers and appears to have several ~unctions. It may act as a source of nutrition for the bacteria. It may serve a~ a physical barrier. Most importantly, surface polysaccharides determine the specific sur~ace in~eractio~s of the bacterial cell.
Thig phenomena ~as far reaching effects. For example the ability of Streptococcus mutans to colonize teeth~ 5eJo3,~e~9~ sallvarius to colonize gum~, Bacteroides fragilus to colonize the inte~tine, and Group A streptococci to colonize the throat and skin are all manifestations of a complex interaction between ~pecific surface polysaccharides and specific lectins, which are proteins that bind to specific polysaccharides.
The importance of bacterial surface and medical de~ice rela~ed infections i~ best illu~trated by coagula e negati~e staphylococci. S. epldermidis, ~he mQst important and common of the coagulase nega~ive staphylococci, was previously considered a non-pathogenic organi~m. It has now emerged as the most common cause of foreign body infection and nosocomial sepsis. It ds the major cause of prosthetic valve endocarditis, vascular graft infection, artificial hip and knee infection, and catheter related epsis. Although less virulent than S.
aureus and many other ~acteria, it is highly resistant ~o mos~ antimicrobials except vancomycin and rifampin.
In ~he early 1980's, electron microscopy studies demonRtrated that certain strains of S.
epidermidi~ produce an extracellular slime like subst~noé. The extracellular slime is a complex substance compo~ed mostly of poly~accharlde.
The production of slime by an organism enables it to adhere to surfaces of in~ertable or implantable de~ice~ and cau~e infection. The slime appears to contain a galactose rich polysaccharide "adh sive" which mediates attachment of the orga~iqm ts polymers. It also contains W093/10~7 PCr/US92/10413 a polysaccharide substance that accumulates after adherence occurs and cements the organism to the medical de~ice.
~ esides adhesion, the slime appears to ha~e other functions. It binds to glycopeptide antibiotics including vancomycin. This may explain why most S.
ep}dermidis infections do not respond to antimicrobial ~:
therapy alone. When infection occurs on an inserted or implan~ed device, removal of the device is usually required. Slime also interferes with cer~ain immune responses.
Tha extracellular slime of S. epiderm~idis is really a manifes~ation of exuberant production of urface polysaccharide. The quantitative production appears to be regulated by a complex mechanism that turns on and off production based upon the local e~vironment. Although S.
epidermidi~ has been the focus of much of the re~earch on ~ .
foreign-body infections, this concept has been studied in o~her organisms. Colonization by pseudomonas ~pecies on the interior surface of PVC and o~her ~ipes has demonstrated a g}ycocalyx ma8s that ~hields organi~ms from disinfectants including chlorine~ phenolics, .`
quaternaryammonlum, and iodophor disinfectants. Once a bacterial glycocalyx is formed, it is very difficult to break down.
The development of pol~mers that contain ~ `~
antimicrobial properties has important implications for both medicine and lndu~try. Aside from factors related to bacterial poly~accharideR, the coating of the foreign body by proteins (albumin, fibronectin, platelets) from the ho~t~ a~ well as a variety of ~actor~ related to the polymer itsel~ undoubtedly af~ect the risk of in~ection.
Several approaches have been utilized to produce medical devicea made of or with polymer~ with antimicrobial propertieB~ a~ de~cribed, for example, in U.S. 4,769,013, U.5. 4,713,402.ana U.S. 4,886,505. . ~ :
Antimicrobial agent~ can be incorporated during the : ~

W093/10~7 PCr/US92/10413 212~167 production process or grafted into the surface a~
described in U.S. 4,925,668. Howe~er, even broadspectrum antibiotic3 eventually lead to the selection of resistant organi3ms. Selection of opportunistic fungi, resistant gram negati~e rods, S. epidermidis, and en~erococci is likely. In addition, unless the "delivery'l of ~he antibiotic is rapid, potent, and long lasting, formation of the protecti~e glycocalyx will prevent its effectiveness. In addition, many antibiotics produce allergic reactions in ~ome patients.
The pre~ent invention is based o~ an alternati~e approach, namely in~erference with the adherence of bacteria to polymeric surfaces of medical de~ices~ Studie~ ha~e demonstrated ~hat both the degree of slime and adhesive production influence and correlate with the degree of bacterial adherence to silastic catheter~. S~ aemolyticus, unlike S ~Ei~s~iglS do not produce slime and are a very uncon~on cause of catheter related infection. As described herein, substances that preve~t or reduce ~he production of slime by bacteria reduce ~heir adherence and thus reduce the level of growth of microorganisms on the surface of the inserted or implan~ed de~ices.
It has been ob~erved that sodium ~alicylates : :
and certain other compounds can interfere with the production of capsule polysaccharide production in Kleb~iella pneumonia~ Salicylate binds to lipids in ~he outer membrane where biosynthetic enzymes are located. It ha~ been postulated that capsular polysaccharide i~ the backbone of glycocalyx :Eorrnation.
, An object of the present invention is to use ~alicylates and other nonsteroidal anti-inflammatory drug~ (~NSAID"), a~ well as oth~r compound~ such as chelating agent~, to pre~ent the production of slime or surface polysaccharide~ in target microorgani~ms, thereby preventing their adherence and growth on materials used in me~ical device~.

WO93/10~7 P~T/US92/10413 212~i167 ~ :
A urther object of the present invention is to ~;
utilize slime or sur~ace-poly~accharide-inhibiting compounds which have, in addition, anti-platelet and thrombotic properties. This is par~icularly useful since ~he ~ormation of the glycocalyx may be detenmined in part by platelets and fibronectin. The use of such compounds may decrease the incidence of thrombophlebitis as well as~ .
i~fection. -It is a further objective of the present inventio~ to reduce bac~erial growth on implanted devices u~ing compounds that are relatively non-toxic. . --The~e and other objectives are accompli~hed by .
the inventio~ described in detail below.

SUMMARY OF ~ y~ ON
A~ embodied herein, the foregoing ~d ot~1er object are achieved by the pre~ent in~e~tion whi~h in~olves the u~e of salicylic acid and other similarly-acting compounds to i~hibit he formation of microbial slime or ~urface poly~accharides, thus interfering with their ability to adhere to invasive medical de~ices and thereby cau~e infection~ :

DET~ILED DESCRIPTION OF THE INVENTION
Described herein is a method for preventing the:.~
adherence and growth of microorganisms on catheters as ~`
well as other in~ertable or implantable medical devices -~
using slime-inhibiting compounds. Reduction of the slime~ ` ~
production by such microorgani~ms reduce,q their ability~.:
to adhere to the medical device thus reducing ~he risk of~;
infecti~n and nosocomial sepsia.
The present invention i~ based on the ~isco~ery that by i~hibiting the adherence of bacteria to catheter~
a~d other medically related foreign bodies, the risk of :
infection and sep~is can be reduced, and the re~idence time in which the medical device can remain in the body can be increased. The adherence of the bacteria to the W093/10~7 PCT/US92/1~413 212~1fi7 medical device is inhibited by using a compound that interferes with the ability of the microorganism to produce a slime. The term sllme, as used herein, includes the extracellular and capsular substance, composed to a large extent of extracellular polysaccharide, which is produced by many microorganisms, including coagulase negative staphylococci such as S. epidermidis and S.
aureus, Escherichia coll, pseudomonas and o~her gram negati~e rods, as well as other microorganisms.
A slime-inhibiting compound is a substance or collection of ~ubstances which inhibits either production of the slime produced by a microorganism, or a component o~ the slime, such as the polysaccharide compone~t.
Regardless of the component of the slime that it inhibits, the slime-inhibitor reduces the ability of a microorganism t~ adhere to a polymeric surface. Slime inhibiting compounds include, but are not limited to, N5AID such as acetyl~alicylic acid (aspirin), salicylate, bis-salicyla~e, benzyl-benzoic acid, diflunisal, fendosalr indomethacin, acemetacin, cinmetaci~, sulindac, tolmetin, zomepirac, diclofenac, fenclofenac, isoxepac, ibuprofen, flurbiprofen, naproxen, ketoprof en, fenoprofen, benoxaprofen, indoprofen, pixprofen, carprofen, mefenamic acid, flufenamic acîd, meclofenamate, niflumic acid, tolfenamic acid, flunixin, clonixin, phenylbutazone, feprazone, apazone, trimethazone, mofebutazone, kebuzone, suxibuzone, ~:
piroxicam, isoxicam and tenoxicam, as well as chelating age~ts. ~.
As contemplated herein, medically implanted or in~er~é~ devices include those inserted percutaneou~ly or thxough an orifice/ or implanted for short or long range~
of time as well a permanently. Such devices include catheter~ a~ well a~ sutures, heart ~alves, gr~fts such a3 vascular or other ti~sue grafts and prosthetic devices such as artificial hips and knees. Such devices are generally made of a polymeric material such a~ silastic :

WO93/10~7 2 1 2 S` 1 6 7 PCT/US92/10413 or other silicone-based material, polyethylene tecephtalate (PET), dacron, kni~ted dacron, velour ~acron, polyglacin, chromic gut, nylon, silk, bo~ine arterial graft, polyethylene (PE), polyurethane, polyvinyl chloride, silastic elastomer, silicone rubber, PMMA [poly-(methyl methacrylate), latex, polypropylene (PP), titanium, cellulose, poly vinyl] alcohol (PVA), poly (hydroxye~hyl methacrylate (PHEMA), poly (glycolic acid), poly (acrylonitrile) (PAN), floroethylene-co-hexafluoropropylene (FEP), teflon ~PTFE) and Co-Cr alloys.
The slime i~hibitor may be added to the material on which microbial growth is to be inhibited by Rpraying, dipping, soaking, or by incorporation into the material itself. Alterna~i~ely, the inhibitor may be incorporated into a secondary pol~mer used to coa~ the surface of the medical de~ice. Such a secondary polymer may have slow release properties that allow for the gradual release of the inhibitor into the microenvironment of the devi~e. :: :
Several of the slime-inhibitors u~ed to practice the present invention have additional ~herapeutic properties. Accordingly, their use is often suggested in conjunction with medical implants, o~tensibly to decrea~e swelling around the site of implantatio~. For example, in U.S. 4,769,013 the use of ~alicylate as an analgesic or anesthetic in conjunction . : ;
with a medical ma~erial is suggested. In addition, drugs described herein have been incorporated into drug delivery devices because of their therapeutic properties.
However,~the level of compound used in such circumstances must be relatively high to achieve the desired ~ .
therapeutic result.
I~ contrast, and because the present in~ention contempl~tes use of a level of compound sufficient only :
to inhibit slime formation within the microe~ironment of the device, the levels of the compounds described herein a are below the level necessary ~or therapeutic systemic effect. Generally, the amoun~ of inhibitor utilized herein to prevent production of polysaccharide production and adherence to the device, as measured by concentration on ~he surface of the de~ice, is between about l and about 20mM. This level is believed to be sufficient to decrease the incidence o~ thrombophlebitis associated with the device due to the known a~ti-platelet acti~ity of NSAID.
According to one preferred embodiment, distribution of the inhibitor on the device to be inserted or implanted is accomplished by incubating the : :
device in a solution containing the slime-inhibitor. The inhibitor is suspended in a solution, most pre~erably an alcohol-based solution, at a concentration of between about 1 mM and 1 M. The device is incubated within such a solution for between about 15 mimltes and ~4 hours at a temperatuxe of betwee~ about -20C to 25C after which it ~ : :
is air dried. ~ :
Preferably the coating is per~ormed at between ~`
about -20C and 10C. In general, use of the inhibitor in conjunction wi~h alcohol has been found to increa~e the polysaccharide inhibiting properties. When the surface to be treated i~ teflon, however, the alcohol decrea~es ~he effectivenes~ of the slime-inhibitor. When alcohol is used, optimum results are often obtained by incubating at -20C.
Another method makes use of tridodecylemthylammonium chloride (TDMAC) or benzalkonium chloride to bind the slime-inhibiting substance to the cathet~r~or medical device. TDMAC has previously been .~ :
u~ed to coat catheters and other medical de~ices with antibiotic~ a~d heparin.
The ability of a compound to inhibit the production of slime by a microorganism and thereby inhibi~ growth on a medically in~ertable or implantable device can be measured by se~eral methods.

W093/10~ 212 516 7 PCT/US92/10413 Once the de~ice is coated or impregnatec ~ith the compound, the device is exposed to a source of bacteria over a speci~ied period of time, after which the de~ice is washed and the growth of the bacteria on the device measured. Such measurements may includ~ colony counts or other means of quantifying microorganisms, such a~
chemiluminescent or bioluminescent assay, which monitor a :::
p~rticular metabolite as a means of quantifying bacterial load or by radiolabelling techniques. :
A suitable methodulogy for analyzing the ~-effecti~enes~ of an inhibltor in preventing microbial growth on catheters or other medically in~ertable or ;:
implantable devices is described in Example 21.
Although the curre~t application deal~ with medical devices, this concept can be applied i~ a number of industrial areas. Glycocalyx forma~ion by gram negative rod~ occurs in PVC and other plumbing supplie~
The formation of this glycocalyx has been shown to contaminate the manufacturing process of products in whi~h ~ter~ y is vita1. Coating such pipe~ with a NSAID
may minimize this problem.
In addition, ~imilar application~ can be considered in the marine industry where water-borne organisms cau~e destruction. Also contemplated by the pxe~ent in~ention is the use of the NSAID as additives to waterproofing and coatings for boats and other marine :
supplie~.

EXAMPLES
~le 1 ~ The effect of sodium salicylate on the growth characteri~tic~ of various organisms wa~ studied. A slime producing strain of coagulaRe negative staphylo~occus wa~
grown i~ increasing concentration of salicylate in two :-di~ferent types of media, chemically defined media (CDM) and tripticase ~oy prot~ (TSB~. The resultant bacterial cou~ts w~re a~ follows:
.

W093/10~7 PCT/~S92/10413 212~i6~

CDM TSB
Control 2.3 x l09 l. 2 X 109 lmM 7 2 x 108 1.4 x l09 5mM ~.3 x lo8 5.7 x lo8 lOmM 5.7 x 108 5.2 x 108 25mM 2.3 ~ l08 3.~ x 107 These studies demonstrated that salicylate does not have a~timicrobial properties. It did not inhibit the . - ;
growth o~ coagulase negative staphylococci in either chemically defined media or in comm rcially prepared try~ica~e soy broth. Similar growth curves were obtained with gram negative rods including E. coli and pseudomonas.

Example 2 As a crude measure of its ability to influence the production of slime, the yield of slime by weigh~
from a one liter broth culture S. ~æ~ grown in the presence of increaslng concentrations of salicylate ~.
was used ~o measure the ability of salicylate to ~: ~
influence the production of slime. .: :
Concentration Yield Control 86 mg.
lmM 68 mg.
5mM 58 mg.
25mM 47 mg.
As noted, the amount of slime decreased with i~crea~ing concentrations of salicylate~ ;

The effect of increasing concentrations o~
~alicylate on the production of slime by S. epidermidis was measured by u5i~g a spectrophotometric assay. The results were as follow~
Concentration ~mM) Optical Density Control l.5 WO93/10~7 212 516 7 PCT/US92/10413 1 mM1.4 2 mM1.3 5 mM .5 10 mM.~8 ~5 mM.~1 `

A progrPs~ive fall in the optical den~ity with increa~ing concentrations of salicyla~e, most evident at 5 mM and above, was observed. : :

Example 4 Selected 3trains o~ ~lime-producing coagula~e negative s~aphylococci (S. epidermidis) were grown in various concentrations of salicylate. After 24 hours growth, ~arious types of catheters were placed in high concen~rati~n of the organisms for 15 mi~utes. This a~ay exposed the catheter~ to a high conce~tration of organisms ~or a shor~ period of time. The ca~heters were washed three times, and rolled onto agar in a standardized manner. The agar plates were incubGted o~ernight, and the number of colo~ies counted, The percent inhibition of adherence was calculated with the following formula:

~ inhibition= 100~ of CFU adhering_in sali~lateL X 100 : :
: (# of CFU adhering in control) with the following results:

Adherence -~
Concentration (CFU plate) Inhi~bi~ion Polyuxethane 0 229 :
1 Mm 236 N.I.
2 Mm 48 79 Teflon 1 mM 5~ 71% ~ .
5 mM 22 87~

W093/10~7 212 51 fi 7 PCT/US92/10413 Silastic 0 325 .:
1 ~ 265 19 2 mM 1~9 54%
~5 mM 77 76~
PVC ''' 1 mM 157 58 S Mm 85 85 Example 5 A similar as~ay to that used in Example 4 was performed u~ing S. aureus and E. coli. This was done using a silastic catheter. The results were as follows:
Adherence Adherence :: :M.
(CFU/plate) tCFU/plate~ .
Concentration E. coli ~ ~ak~. S. aureus ~ nhib.

1 mM 32 64 15~ 4~%
5 mM .5 99 112 61~

This demonstrated an ef~ect wi~h E. coli and S.
aureu~ that was imilar to that observed with S.
,epidermidis . ,.

Examele 6 Catheter segments were incubated o~ernight in salicylate and co~pared to control catheters that were not incubated in salicylate to determine whether the ~.
salicyla~e would coat the polymer surface. .:
: Catheter segments were i~cubated in 100 mM
salicylate overnight at 37C, pH 7Ø The catheter~ were then dried, and dipped into a 5 x 105 CFU/ml coagulase negative~taphylococci for 15 minutes. All studies were . ~ :
done in triplicate.
Adherence (CFU/plate) ~ :
. ontrol Salicylate Inhib.
Silastic 600 317 47 Polyurethane 33 20 ~7 Teflon 35 13 63 .''.'-'; '..,.

WO93/10~7 21~516 7 PCT/US92/10413 : '.'' PVC ~5 S0 41 Example 7 Te~lon, PVC, and silastic catheters were incubated in lO0 mM salicylate at 37 overnight and were incubated with high conceIltrations of bacteria (107 - lo8 CFU/ml). After incubation, the catheters were washed three times, then rolled onto agar and incubated. The colonies were counted. The re~ults were as follows:
. Teflon PVC
E. coli Co~trol 8.0 13 2ll Salicylate 13.0 2 l03 Inhibition 0~ 29~ 5l~ :
P. aer~uqinosa Control 80 275 59 Salicylate 1 200 3 Inhibition lOû~ 27% 9 The inhibitior~ was most obvious with p~eudomonas regardless of the type of polymer u~ed. The E coli did not adhere as well as pseudomonas regardless of ~he catheter type.
Exampl e 8 A ~tudy similar to that described in Example 7 was done with a s~r~ller inoculum of. ~105 CFU/ml) of .
aureus with the xesults as ~ollows: ~ ;
Adherence CFU/plate) Inhibition Teflon .~ ~ Control 14 7 ~alicylate 54 63%
PVC
Control 192 S~ 136 30%
Sila~tic Control 296 WO93/10~7 . PCT~US92/10413 21~S167 SAL . 224 24%
Example 9 .
Silastic and polyurethane catheters were incubated in 95~ EtOH and 95% EtOH and 200 mM salicylate at pH 7.0 for 2 hours at -20C. The catheters were air dried and incubated in broth containing l05 CFU/ml S.
epidermidls ~or 15 minutes at 37C. The catheters were then washed and rolled onto agar. The results on two identical experiments were a~ follows:
Trial l Control Salicylate l~lbi~i9a Polyurethane 1~3 91 36 Silastic 461 35 92 Trial ?
Control _lic~late Inhibitio~ :
Silastic 37 .67 9 PVC . 60 50 17 Teflon 19 20 0~ -Polyurethane 138 57 59~
Exam~le l0 ;
Similar experiments to those described in Example 9 were conducted using E. coli. A high ~-.
concentration o~ organisms (l06) was used. Catheter se~ments were incubated for 2 hours in 200 mM salicylate in 95~ ethanol. The catheters were dried and placed in. . .
the E. coli cultures at room temperature. They were allowed to i~cubate for 18 hours. The results were as ~llows: :~
(C~U/plate) ~ Control Salicylate Inhibit~ion Polyurethane 77 l0 88 PVC 21 3 . 86% -~
Silas~ic 50 3 96 xample ll ~ Silastic catheter~ prepared as described in :~
Example 9 were incubated in cultures of S. epidermidis .. - -.~ , . - - ,, ; ~, - , ; "

0~7 PCT/US92/10~13 W~93/1 2125167 for three days at 37C.
CFU/plate Control Salicylate Inhibition l~ 6 ~0 Example 12 Silastic catheters prepared as de~cribed in Example 9 were incubated in cultures of E. coli for three days.
(10~ CFU/ml).
CFU/plate ContrQ~ Sali~late ~I~L~L~i~n l~00 700 5~
Exc~mple l3 . :
Polyurethane and sila~tic catheters were soaked overnight in ~aryi~g conce~trations of salicylic acid in ethanol at ~20C and then exposed to coagulase negative staphylococci and E. coli for 4 h~E~ at 37C. They were ~ :
washed and rolled as per ~he protocol described in Example 9.
oa~lase Ne~ative Stap~hylococci ~Polyurethane - tubing) E~ Ss5~ ha~ CFU/mm Control 7.33 ~400 20.0 Salicylate 200mM 7.l9 310 14.6 Salicylate 600mM 6.77 50 2.4 Ibuprofen 400mM 7.22 233 ll.5 Ibuprofen 200mM 7.02 352 l8.1 E. coli (silastic tubing) Count/Plate 5 Con~rol 250 12.0 ~a~icylate 200~M 226 ll.6 Salicylate 600mM 32 l.6 Ibuprofen-400mM 238 12.0 Ibuprofe~ 200mM 185 9.6 Catheter~ treated with salicylate and ibuprofen as described in Example 9 were incuhated in phosphate W0~3/10~7 212 516 7 PCT/US~2/10413 buffered saline having a concen~ration of 103 CFU/ml E.
coli for ~ix days at 37C. Thi~ produced a consta~t concentration of organisms.

Coatln~ (CFU/plate) Inhibition -Contr~l 240 200 mM salicylate 121 50~ -100 mM Ibupro~en 70 71~ .

De~pite six days of incuba~ion, the inhibi~ion was impressive. I~ was greater with ibuprofen than ~alicylate in this experiment.

Exam~le_15 .
Polyurethane and silastic catheters were incubated in ibuprofen, acetyl-sa:licylate, and ben~oyl- ::
be~zoic acid with 95~ e~hanol for 2 hours. The catheter~
were then incubated in S. e~idermidis as described in - :
Example 9. The results were as follows:
Polyu~rethane CFU/plate1 Inhi~ition : .
Control ~95 ~.
Acetyl-Salicylate (200mM)127 57~
Salicylate ~200m~) 270 9~ :
Ibuprofen (lOOmM) 166 4 Benzyl benzoic (lOOmM) 333 0 '' '' Sila~t1c : ~:
Control 52 ~:~
Acetyl-Salicylate (~OOmM) 7 86 Salicylate (200mM) 33 36 Benæyl benzoic (lOOmM) 9 83~
~!EIl~ , .. .
Polyurethane catheters were preheated o~ernight ~:~
at 67C a~d coated in the compounds listed below at -20C
in 95~ ethanol. They were then incubated in coagulase negative ~taphylococci at 37 for 18 hours, and wa~hed three time~ in phospha~e buffered ~aline. ATP wa WO93~10847 2 1 2 ~ 1 6 7 PCT/US~2/10413 extracted with extralight and read with firelight in a dynatech luminometer reader. ~.
Units of ll~h~ (measured at 48) Control .62 Salicylate .l9 Acetyl~alicylate.06 ~cetaminophen 2.4 Ibuprofen .32 : :
Phenylbutazone - .02 Indomethacin .07 -~
The units of light are a reflection of the amount of ATP relea~ed and bacteria that have adhered ~o the polymer. The experiment was repeated, but by growing the organi~m~ directly in the microllte wells. Culture~
of coagula~e negative staphylococci were grown in the ~::
pre~ence of 2mM NSAID in microlite wells, washed and treated with extralight and firelight.

L~ L~gh~ ~measured a~ 483 Control ~g.o Acetylsalicylate 13.0 Salicyla~e 15.0 Ibuprofen g.o Acetaminophen 108.0 I~dome~hacin 9.2 Phenylbuta one 19.1 ~xam~
Several experiments were done with gram neg~tive rods in urine in8tead of broth. Silastic catheters were prepared as previou~ly described and were incubated for 4-5 hour~ at 37C. All studies were do~e i~ triplet.
, E. coli Incubated in Urine (5 Hour~) Silastic Catheter CFU~mM Inhibition Control 25.0 S~licylic Acid (200mM~ 17.0 31%
Salicylic ~cid (609mM) 1.5 94 Klebsiella pneumoniae (4 Hours) Silastic Catheter CFU/mM Inhibition . .
Control 14.0 Salicylic Acid (200mM) 4.9 65 Salicylic ~cid (600mM) 1.8 87 E. Aero~enes in Urine ~5 Hours) Silastic Catheter CFU/mM Inhibition Control 15 5 -~
Salicylic Acid ~200mM) 9 8 37% ;~
Salicylic Acid (600mM) 4.3 73 Example 18 .~
In an at~empt to determine-the length of the -~-ob erved effect, silastic catheters were ineuba~ed in ~alicylic acid as described, and then placed in sterile urine for 4 days. At the end o~ this period, the -~
ca~heters were removed and then p:Laced i~ a broth culture of E. coli. Results are the mean of three trials.
a~tic C ~ho~er CFU/mM Inhibition ~- :
Control 13.2 `~
Salicylic Acid ~200mM) 9.6 27 Salicylic Acid (600m~) ~.9 7~
Thi~ experiment demonstrat~d that the coating is not lo~t immediately after the catheter is placed in :~
an aqueous ~olution.
Example 19 :S. epidermidls was radi~labeled by including 1 ~Ci of (14C - ~odium acetate) in the preliminary overnight ~:
culture. The catheter segments were exposed to the broth ~ `
culture ~vernight at 37C. The catheters were ~igorously washed.-'~ 8aline, air dried, and placed in scintillation .
vials f~r counting.
TSB with NaAc (l.2 - ~4C~ .
Overnight at 37C
Sila~tic_~atheter CPM
Control l4al.0 Salicylic Acid ~200mM~ 528.0 S~licylic Acid (600mM) 165.0 '' W093/tO~7 2 ~ 2 ~ 1 6 7 PCT/U~9~/10413 Exam~le 20 Another embodiment uses tridodecylemthylammonium chloride (TDM~C) or benæalkonium chloride which coats the catheters and also binds to the salicylates. Silastic ca~he~ers tha had been preheated were coated in 5~ TDM~C
in ethanol ~or 40 minutes at room temperature. The catheter segme~ts were vigorou~ly wa~hed with sterile water and air dried. The ~egments were then immer~ed in ethanol, 200mM salicylic acid and 600mM salicylic acid overnight at -20C. The catheters were air dried and immersed in a tryptica e ~oy broth clllture of E. coli or S. e~idermidis at 37C. Ca~he~ers were wa hed 3 times in 3 change~ of ~erile saline and rolled on Mueller-Hinton Agar plates. The plates were incuba~ed overnight at 37C
and the colonies were counted.
CFU/ CFU/
Plate mM Inhibition E. coli Control 143.0 6.5 (5 Hour Salicylic Acid (200mM) 23.0 1.1 83 Incubation) Salicylic ACid (600mM) 1.5 0.07 99 CFU/ CFU/
Plate mM _nhibition S. epidermidis Contxol 9l.0 4.3 (Overnight Salicylic Acid t200mM) 81.0 3.9 9 In~ubation) Salicylic Acid (600mM) 52.0 2.6 40 Ex~mple_21 The following i8 a recommended method for determining whether a particular compound inhibits slime production and adherence to a medical de~ice:
l~ Prepare test coating ~olution~ at desired .~,'concentrations. Prepare steri~e 3 cm ~ection of tubing.
2. Incubate tubing pieces in sterile water at 67C
overnight, dry 1 hour, then expose to test solutions and controls at -20C for 2 hours.
E~ ure that all tubing are i~nersed in ~olution .
3. Rernove the tubing and dry coated samples in a sterile field. Mark tubing 1 cm from end.

WO93/10~7 212 51 6 7 PCT/US92/l04l3 4. Assemble a sterile 3 cm syringe with a sterile i~dustrial blunt syringe which will fit ~ecurely into the tubing to be tested.

5. A~tach the marked end o~ the 3 cm lengths of coated tubing to the needle. Withdraw the plunger rom the syringe to about the 2 or 3 cc mark. : ~:

6. Place 15 ml of a 106 bacterial suspen~ion into a sterile 50 cc tube and place up to 3 tube~ into each tube. Incubate at 37C for 15 minutPs. The ~: :
le~gth of incubation and inoculum siæe can be varied.

7. Tra~sfer each ~ubing Begment into a ~epaxate 15 :
ml sterile tube contai~ing approximately 5 ml of ~terile ~aline. Bach tuke is ~igorously washed by drawing saline back and forth through the tube 3 times.

8. The process ig repeated until a total of 3 washes in 3 separate salin~ tubes i~ completed.

9. A 1 cm segment of the di~tal catheter i~ ~ut off a~d discarded. :~

10. The remaining 2 cm section was quantitatively rolled over a blood agar plate in 4 directions. ~.
The plates are incubated overnight a 37C and the colonies are counted. ~-~
~1. The catheter segments are carefully measured so that the number of CFU/mm catheter can be ~ ::
calculated. -~ , . . .

Claims

IN THE CLAIMS:

1. A method of reducing infection associated with an implantable or insertable medical device comprising distributing on said device an effective amount of a slime-inhibiting compound.

2. A method according to claim 1 wherein said slime-inhibiting compound is a chelating agent.

3. A method according to claim 1 wherein said slime-inhibiting compound is a NSAID.

4. A method according to claim 3 wherein said NSAID is selected from the group consisting of salicylic acid, acetylsalicylic acid (aspirin), bis-salicylate, benzyl-benzoic acid, diflunisal, fendosal, indomethacin, acemetacin, cinmetacin, sulindac, tolmetin zomepirac, diclofenac, fenclofenac, isoxepac, ibuproben, flurbiprofen, naproxen, Xetoprofen, fenoprofen, benoxaprofen, indoprofen, pirprofen, carprofen, mefenamic acid, flufenamic acid, meclofenamate, niflumic acid, tolfenamic acid, flunixin, clonixin, phenylbutazone, feprazone, apazone, trimethazone, mofebutazone, kebuzone, suxibuzone, piroxicam, isoxicam and tenoxicam.

5. A method according to claim 4 wherein said NSAID is salicylic acid or sodium salicylate.

6. A method according to claim 4 wherein said NSAID is ibuprofen.

7. A method according to claim 1 wherein said slime-inhibiting compound is distributed on the medical device by incorporating it into the medical material during manufacture of said material.

8. A method according to claim 1 wherein said slime-inhibiting compound is distributed on said device using TDMAC or benzalkonium chloride.

9. A method according to claim 1 wherein said slime-inhibiting compound is distributed on said device by soaking the device in a solution containing the slime-inhibiting compound.

10. A method according to claim 9 wherein the concentration of the slime-inhibiting compound in said solution is between about 1 and about 1 M.

11. A method according to claim 9 wherein said soaking is conducted for between about 10 minutes and about 24 hours.

12. A method according to claim 9 wherein the solution is alcohol based.

13. A method according to claim 11 wherein said alcohol consists essentially of ethanol.

14. A method according to claim 9 wherein said soaking is conducted at between about -20° and 25°C.

15. A method according to claim 13 wherein said soaking is conducted at refrigerated temperatures.

16. A method according to claim 13 wherein said soaking is conducted at about -20°C.

17. A method according to claim 9 wherein said soaking results in incorporation of slime-inhibiting compound into the medical device material.

18. A method according to claim 1 wherein said device is made of a polymer selected from the group consisting of silastic or other silicone-based material, polyethylene tecephtalate (PET), polyglacin, polydioxanone, chromic gut, nylon, silk, dacron, knitted dacron, velour dacron, bovine arterial graft, polyethylene (PE), polyvinyl chloride (PVC), silastic elastomer, silicone rubber, PMMA [poly-(methyl methacrylate)], latex, polypropylene (PP), titanium, cellulose, polyvinyl alcohol (PVA), poly-(hydroxyethyl methacrylate) (PHEMA), poly-(glycolic acid), poly (acrylonitrile) (PAN), floroethylene-co-hexafluoropropylene (FEP), teflon (PTFE), Co-Cr alloys, PVC, polyurethane, polyester, polytetrafluoroethylene, and biological polymers such as collagen.

19. A method according to claim 1 wherein said slime-inhibiting compound is distributed by coating the device with a polymer containing the slime-inhibiting compound.

20. A method according to claim 19 wherein said polymer has slow release properties.

21. A method according to claim 1 wherein said effective amount of slime-inhibiting compound on or near the surface of the device is between about 1 and about 20 mM.

22. A method of inhibiting the growth of microorganisms on a medical device inserted or implanted in a mammal comprising:
exposing said medical device, prior to insertion or implantation, in a solution, said solution having a concentration of between about 1 mM and about 1 M of a slime-inhibiting compound;
removing said medical device from said solution;
drying said medical device; and inserting or implanting said medical device in the mammal.

23. A method of inhibiting the growth of microorganisms on a medical device inserted or implanted in a mammal comprising:
coating said medical device, prior to insertion or implantation, with a polymer, said polymer having a concentration of between about 1 mM
and about 1 M of a slime-inhibiting compound;
and implanting or inserting said medical device in the mammal.

24. A method according to claim 23 wherein said polymer has slow release properties.

25. A method according to claim 24 wherein said polymer is selected from the group consisting of silastic or other silicone-based material, polyethylene tecephtalate (PET), polyglacin, polydioxanone, chromic gut, nylon, silk, dacron, knitted dacron, velour dacron, bovine arterial graft, polyethylene (PE), polyvinyl chloride (PVC), silastic elastomer, silicone rubber, PMMA
[poly-(methyl methacrylate)], latex, polypropylene (PP), titanium, cellulose, polyvinyl alcohol (PVA), poly-(hydroxyethyl methacrylate) (PHEMA), poly-(glycolic acid), poly (acrylonitrile) (PAN), floroethylene-co-hexafluoropropylene (FEP), teflon (PTFE), Co-Cr alloys, PVC, polyurethane, polyester, polytetrafluoroethylene, and biological polymers such as collagen.

26. A method of reducing infection associated with an insertable or implantable medical device comprising exposing said device, prior to insertion or implantation, with a slime-inhibiting compound, said exposure being sufficient to coat the device with an amount of inhibiting compound capable of reducing the amount of microbial growth on said device upon implantation, but being at an amount insufficient to produce systemic therapeutic benefits.

27. A method according to claim 26 wherein said device is a catheter.

28. A method of reducing thrombophlebitis associated with an implantable or insertable medical device comprising distributing on said device an effective amount of a NSAID.

29. A method according to claim 28 wherein said NSAID is selected from the group consisting of salicylic acid, acetylsalicylic acid (aspirin), bis-salicylate, benzyl-benzoic acid, diflunisal, fendosal indomethacin, acemetacin, cinmetacin, sulindac, tolmetin, zomepirac, diclofenac, fenclofenac, isoxepac, ibuprofen, flurbiprofen, naproxen, ketoprofen, fenoprofen, benoxaprofen, indoprofen, pirprofen, carprofen, mefenamic acid, flufenamic acid, meclofenamate, niflumic acid, tolfenamic acid, flunixin, clonixin, phenylbutazone, feprazone, apazone, trimethazone, mofebutazone, kebuzone, suxibuzone, piroxicam, isoxicam and tenoxicam.

30. An insertable or implantable medical device having reduced risk of causing infection after insertion or implantation comprising a device having distributed thereon an effective amount of a slime-inhibiting compound.

31. A device according to claim 30 wherein said slime inhibiting compound is present at a level of between about 1 and about 20mM.

32. A device according to claim 30 wherein said device is comprised of a polymer selected from the group consisting of silastic or other silicone-based material, polyethylene tecephtalate (PET), polyglacin, polydioxanone, chromic gut, nylon, silk, dacron, knitted dacron, velour dacron, bovine arterial graft, polyethylene (PE), polyvinyl chloride (PVC), silastic elastomer, silicone rubber, PMMA [poly-(methyl methacrylate)], latex, polypropylene (PP), titanium, cellulose, polyvinyl alcohol (PVA), poly-(hydroxyethyl methacrylate) (PHEMA), poly-(glycolic acid), poly (acrylonitrile) (PAN), floroethylene-co-hexafluoropropylene (FEP), teflon (PTFE), Co-cr alloys, PVC, polyurethane, polyester, polytetrafluoroethylene, and biological polymers such as collagen.

33. A device according to claim 30 wherein said slime-inhibiting compound is a chelating agent.

34. A device according to claim 30 wherein said slime-inhibiting compound is a NSAID.

35. A device according to claim 34 wherein said NSAID is selected from the group consisting of salicylic acid, acetylsalicylic acid (aspirin), bis-salicylate, benzyl-benzoic acid, diflunisal, fendosal, indomethacin, acemetacin, cinmetacin, sulindac, tolmetin, zomepirac, diclofenac, fenclofenac, isoxepac, ibuprofen, flurbiprofen, naproxen, ketoprofen, fenoprofen, benoxaprofen, indoprofen, pirprofen, carprofen, mefenamic acid, flufenamic acid, meclofenamate, niflumic acid, tolfenamic acid, flunixin, clonixin, phenylbutazone, feprazone, apazone, trimethazone, mofebutazone, kebuzone, suxibuzone, piroxicam, isoxicam and tenoxicam.

36. A device according to claim 35 wherein said NSAID is salicylic acid or a salt thereof.

37. A device according to claim 35 wherein said NSAID is ibuprofen.

38. An insertable or implantable medical device having reduced risk of causing thrombophlebitis after insertion or implantation comprising a device having distributed thereon an effective amount of a NSAID.

39. A device according to claim 38 wherein said NSAID is present at a level of between about 1 and about 20mM.

40. A device according to claim 38 wherein said NSAID is selected from the group consisting of salicylic acid, acetylsalicylic acid (aspirin), bis-salicylate, benzyl-benzoic acid, diflunisal, fendosal, indomethacin, acemetacin, cinmetacin, sulindac, tolmetin, zomepirac, diclofenac, fenclofenac, isoxepac, ibuprofen, flurbiprofen, naproxen, ketoprofen, fenoprofen, benoxaprofen, indoprofen, pirprofen, carprofen, mefenamic acid, flufenamic acid, meclofenamate, niflumic acid, tolfenamic acid, flunixin, clonixin, phenylbutazone, feprazone, apazone, trimethazone, mofebutazone, kebuzone, suxibuzone, piroxicam, isoxicam and tenoxicam.