an attack of diarrhoea on the second day, and, for

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1 POSTGRAD. MED. J. (1965), 41, 501 Clinical Trial A COMPARATIVE STUDY OF THE LEVELS OF NALIDIXIC ACID IN PLASMA AND URINE AND ITS ANTIBACTERIAL ACTIVITY IN URINARY INFECTIONS OF PARAPLEGICS N. 0. K. GIBBON, Ch.M., F.R.C.S., Consultant Surgeon. NALIDIXIC ACID, one a series 1, 8- naphthyridine derivatives with antibacterial activity was synsised by Lesher, Froelich, Gruett, Bailey and Brundage (1962). Chemically it is l-ethyl-7-methyl-1, 8-naphthyridine-4-one- 3-carboxylic acid. The pharmacology and toxicology have been documented by Ward-McQuaid, Jichlinski and Macis (1963) and Lishman and Swinney (1963), based on unpublished information made available by Sterling-Winthrop Research Institute. McChesney, Froelich, Lesher, Crain and Rosi (1964) have carried out studies urine levels nalidixic acid in healthy volunteers, in addition to a large series animal experiments. It was found that nalidixic acid attained higher concentrations in human urine and animal kidney tissue than in any or body fluids or organs respectively. The effect nalidixic acid on urinary tract infections has been studied in vitro by Deitz, Froelich and Bailey (1962) and clinically and bacteriologically by Buchbinder, Webb, Anderson and McCabe (1962), Barlow (1963), Carroll (1963), Jameson and Swinney (1963), Lishman and Swinney (1963), McCabe (1963), Slade (1963), Thompson and Rae (1964) and Ward-McQuaid and co-workers (1963). On basis this information we have examined 16 cases in Liverpool Regional Paraplegic Centre at Southport to estimate plasma and urine levels nalidixic acid in patients, and its effect on bacteriological clearance. Methods and Material The 17 patients selected for this trial presented no clinical sign or symptom urinary infection except for turbid or purulent urine. Cases were selected on basis urine cultures and sensitivity tests carried out on all paraplegic patients in unit. Only patients who had organisms in urine sensitive to nalidixic acid were included in this trial. Among 17 cases 2 were female and 15 male, ages ranging from 19 to 70 years. 15 cases were given nalidixic acid 1 g. 6 hourly, 11 whom received drug for 7 days, 3 patients for 12 days J. G. BENSTEAD, M.A., M.D., Consultant Pathologist. G. C. MISRA, M.B., B.S., Research Fellow. Liverpool Regional Paraplegic Centre, Southport. p and one patient for one day. This last patient had an attack diarrhoea on second day, and, for this reason drug was stopped after one day's rapy. This patient was excluded from series. 2 cases were given 0.5 g. nalidixic acid every 6 hours for 7 days and 4 patients had a second course extending from 2-4 weeks. In all cases drug was administered orally and on first day only it was given every 4 hours to fit in with collection blood and urine samples. Plasma and Urine Assay For this purpose five samples urine and blood were collected on day commencement rapy. One sample each was taken as a control specimen before drug was administered. Four samples were collected at intervals 1, 2, 4 and 8 hours after administration nalidixic acid. The plasma was separated and both urine and plasma were refrigerated at 4'C until assay was done. On 2nd and every alternate day a sample urine only was collected for drug assay and collection time varied from 2 to 5 hours after rapy. Collections both 'blood and urine were made on 3rd and every alternate day until completion rapy. In two patients on nalidixic acid 0.5 g. q.i.d., an assay drug in urine and plasma was made after completion rapy, to check residual concentration. For this, samples urine and blood were collected at 151 hours, 161 hours, 38' hours and 39j hours after rapy. A physicochemical method was adopted for determination nalidixic acid. This was based on principle that it is readily extracted from an aqueous medium at ph 1-6 by toluene and can be transferred from toluene into water at ph 9.0. On acidification this aqueous phase to ph 0-1, compound becomes fluorescent. The activating wavelength is 320 mu (uncorrected) and fluorescent wave-length is 350 miu (uncorrected), as determined on an Aminco Bowman spectrophotluorimeter. A calibration graph was prepared by adding known amounts nalidixic acid to blank biological fluids and subjecting se standards to analytical procedures. Recoveries were greater than 90% for range ,ug. Bacteriological Studies were made on urine patients by a daily collection starting from day rapy. 12 out 16 patients had

2 502 POSTGRADUATE MEDICAL JOURNAL August, 1965 Name TABLE 1 ASSAY OF NALIDIxIC ACID IN PLASMA AND URINE ON THE 1ST DAY OF THERAPY, IN jug. /ml. Daily dose Level drug Level drug Level drug Level drug 1 hr. after rapy 2 hrs. after rapy 4 hrs. after rapy 8 hrs. after rapy nalidixic acid Plasma Urine Plasma Urine Plasma Urine Plasma Urine Mr.W.R. 1 g. q.i.d Mrs. C. V.,, Mr. I. B.,, Mr. W. D.,, <0.1 < Mr. A. G.,, Mr. K. M.,, Mr. N. H.,, Mr. J. S.,, Mr. J. P.,, Mr. S. J. B.,, Mr. J. H.,, Mr. J. S.,, Mr. W. J.,, Mrs. B. B.,, Mr. J. H.,, Mr. A. C. 0.5 g q.i.d. Mr. E. W.,, indwelling caters, and urine in se cases was taken by allowing first few ml. to escape from end cater, after which a specimen ml. was collected. Collection. urine in or four was midstream. All specimens were refrigerated after collection and examined within three hours. The following investigations were made on all urine specimens: 1. Culture: This was carried out by plating a standard 2 mm. loopful uncentrifuged urine into a blood agar and a MacConkey agar plate. These plates were incubated at 37 C. overnight -and examined following day. The organisms commonly isolated were E. coli, A. aerogenes, atypical coliforms (those coliforms not falling into two above groups), Proteus Spp., Ps. pyocyanea and Strep. faecalis. 2. Sensitivity Gram-negative Bacilli: A disc sensitivity technique was employed making use commercially available paper sensitivity discs containing various antibacterial agents (Tables 3 & 4). In case nalidixic acid 5, 30 and 60 ug. discs were used initially, but later on only 30 ug. discs were used. A well defined zone inhibition around disc was recorded as sign sensitivity and growth right up to disc or near disc as resistance. No attempt was made to measure zones inhibition. Sensitivity was studied against all Gram-negative bacilli in urine, but not against Gram-positive organisms such as Strep. fagcalis, Strep. pyogenes and Staphylococci following unpublished experimental data in files Sterling-Winthrop Research Institute. Recent reports by Lishman and Swinney (1963), Barlow (1963) and Ward-McQuaid and ors (1963) show, however, that a few strains se Gram-positive organisms may sometimes be sensitive to nalidixic acid and occasionally may be responsive to treatment. In our experience, however, se were never cleared up with nalidixic acid rapy. 3. Bacterial Counts: were made by a pour-plate method using serial dilutions urine in digest broth from 10- to I0V6. One ml. each dilution urine was mixed with 10 ml. melted nutrient agar at 50'C in a Petri-dish. The agar was allowed to solidify and this was incubated overnight. Counts were made on plates showing colonies. Any count less than 10,000 organisms per ml. was considered as showing that infection was absent. (Kass, 1955). 4. Minimum Inhibitory Concentration: Tests were carried out with nalidixic acid on all Gramnegative bacilli isolated during trial. 91 different strains organisms were tested in this way and those strains that were present on more than one occasion were tested each time y were isolated. Serial doubling dilutions nalidixic acid solution were made in 1.0 ml. digest broth giving concentrations from 1,g./ml. to 256,gg./ml. The tubes were inoculated with 1 drop (0.02 ml.) a 1/1000 dilution an overnight broth culture test organisms and incubated for 18 hours at 37 C. The minimum inhibitory concentration was recorded as minimum concentration nalidixic acid which prevented visible growth. 5. Pus Cell Count: The method adopted by McGeachie and Kennedy (1963) was used. 10 ml. well mixed urine were centrifuged in a graduated tube at 3,000 r.p.m. for 3 minutes. The supernatant liquid was removed leaving 0.5 ml. urine and sediment. This was mixed using a Pasteur pipette and a Neubauer counting chamber was filled with suspension. The white blood cells in area indicated were counted and if counts were low, several similar areas were counted and mean taken. The numbers counted were taken as cells per measured area. In case urine with a very high cell count uncentrifuged urine was used, and result multiplied by 20. As found by McGeachie and Kennedy (1963), a count 10 or more leucocytes per measured area was taken as significant.

3 4ugust, 1965 GIBBON, BENSTEAD AND MISRA: Nalidixic Acid II wc:+=cu s- 3) -4 CIA 'IO C IIHI I-I I- -.f~~k) N t '3.J wo < >X< >w ac r 4N*. > - LA~ - H43- A00 ooo0 I) LA -.AJt -w-po--o o CD U) CDS B > 9+> > 9 - H99-H-Hzz CA -t Li>s- S s tss U (-o > > soooo(az 0 t% wo >ALi <o ;, obo Y H H 00JtW),0 + LACD LA 00O an 0 U - I-I H >s - 1To - Is v I I b I 1 00I I t. to!h U) - e F 0% 0%<I -',11 l A~0tN0 0 OI 9IIIIIoI!. -4 A IIoI II I II > 9ol 1 oo! CDH U)

4 504 POSTGRADUATE MEDICAL JOURNAL August, 1965 TABLE 3 RELATIVE SENSITIVITY OF 25 STRAINS OF ORGANISMS ISOLATED FROM THE PRETHERAPY SPECIMENS OF URINE IN THE 17 CASES SELECTED FOR TRIAL No. ot individual No. strains organisms sensitive to different Organisms strains chemorapeutic agents Nalidixic Chloram- Nitrur- Sulpho- Tetra- Acid phenicol antoin namides cycline Kanamycin 30 Ag. disc 100,g. disc 200 Ag. disc 200,g. disc 100,g. disc 30,g. disc E. coli Proteus spp Ps. pyocyanea A. wrogenes Atypical coliforms TOTAL TABLE 4 RELATIVE SENSITIVITY OF 102 STRAINS OF ORGANISMS TO DIFFERENT CHEMOTHERAPEUTIC AGENTS No. Organisms individual No. strains organisms sensitive to different strains chemorapeutic agents Nalidixic Chloram- Nitrur- Sulpho- Tetra- Mandela- Kanamy- Acid phenicol antoin namide cycline mine cin 30,gLg. 30,utg. 100 jtg. 200,jg. 200,ug. 100,ug. 3 mg. disc disc disc disc disc disc disc E. coli /36 44 Proteus spp Not 28 tested Ps. pyocyanea Resistant Resistant 2 8/8 3 A. wrogenes Resistant 5 4/4 6 Atypical coliforms Resistant Resistant 1/4 4 TOTAL /52 85 Results Plasma and Urine Assay: A wide range variation was noted in results assay nalidixic acid in plasma and urine different patients and even in that same patient at any particular hour after rapy (Tables 1, 2). On first day rapy when 4 samples were taken, concentration drug in urine after 1 hour rapy ranged from 2.75 ug./ml. to 240,ug./ml. After second hour it extended from 5.8,ug./ml. to 248,ug. /ml. and after 4th hour range was from 22.5,ug./ml. to 252,tg./ml. The sample urine which was collected 8 hours after commencement rapy showed a range from 20,ug./ml. to 186,ug./ml. All patients, course, had ir 2nd daily dose nalidixic acid by n. The two patients who had nalidixic acid 0.5 g. q.i.d. did not in fact show any lower concentration drug eir in plasma or in urine, compared to those who had 1 g. q.i.d. On contrary, re was a very high concentration drug in urine one se two patients, but he was without a cater. The results assay on 2nd and subsequent days show similar variation in concentration drug both in plasma and urine, but not to such a great extent (Table 2). The lowest concentration drug in a sample urine taken after 1st day rapy was found to be 17.25,ug./ml., and in more than 90% samples concentration drug was above 30,ug./ml., (Table 2) irrespective time collection sample; this was usually done from 2 to 5 hours after rapy. The highest level drug was found during 3rd and 4th hour after rapy in majority cases. In one two patients who had 0.5 g. nalidixic acid q.i.d., assay urine at 15, hours after completion rapy, showed 4 gg. nalidixic acid per ml., and at 38+ hours 2 gg./ml. Even though or patient did nol show an equivalent level drug in his urine.

5 August, 1965 GIBBON, BENSTEAD AND MISRA: Nalidixic Acid 505 TABLE 5 MINIMUM INHIBITORY CONCENTRATION OF NALIDIXIC ACID ON 91 DIFFERENT STRAINS OF ORGANISMS IN VITRO No. different strains showing M.I.C. in,g./ml. No. Organisms strains >256 E. coli Proteus spp Ps. pyocyanea Atypical coliforms A. xrogenes TOTAL 91 it is interesting to note that up to 38 hours after rapy re could be some nalidixic acid still present in urine a proportion cases. From this it is reasonable to assume that up to 24 hours after rapy re could be an appreciable level drug present in urine. Bacteriological Studies 102 different strains Gram-negative bacteria were isolated, and studied for relative sensitivity to different chemorapeutic agents in vitro by disc technique (Table 4). These included 25 different strains organisms which were isolated from prerapy samples urine 17 patients selected for trial (Table 3). E. coli: 44 out 49 strains were sensitive to nalidixic acid, whereas only 34 were sensitive to chloramphenicol and 37 to nitrurantoin. In case kanamycin sensitivity was identical, i.e. 44 out 49 (Table 4). Proteus spp.: 27 out 31 strains were sensitive to nalidixic acid as compared with 16 to chloramphenicol. 28 out 31 were sensitive to kanamycin. Ps. pyocyanea: Out 12 strains only 1 was sensitive to nalidixic acid whereas 7 were sensitive to chloramphenicol. A. aerogenes and atypical coliforms: There were 6 strains former and 4 latter. The sensitivity se to nalidixic acid was similar to or agents such as chloramphenicol, kanamycin and nitrurantoin. The sulphonamides and tetracycline were comparatively ineffective. Following Waterworth's report (1962), mandelamine was not used for testing against Proteus spp., and only a few strains or organisms were tested against it (Table 4). Bacterial Count: In most cases it was found difficult to obtain a satisfactory result by pour-plate method, especially in urine with a high bacterial count. (Often count obtained from a particular dilution did not show tenfold increase or decrease on corresponding, preceding or following dilution.) This was almost certainly due to difficulty in obtaining a homogeneous suspension organisms, as a result bacteria being present in small clumps. On whole results were irregular and nothing much was gained from doing this procedure except to gauge lower limit infection. is This because a bacterial count less than was 10,000 regarded as no infection. Pus Cell Count: In 16 patients where daily a pus cell count was done, 9 showed a gressive but pro- irregular fall and 5 se showed complete clearance. Out se 5, 4 associated were with a bacteriological clearance. or In 7, count was extremely irregular two and se in fact showed a increase considerable over initial count. Minimum Inhibitory Concentration: 91 strains organisms which were isolated during or at rapy subsequent check-ups were tested for M.I.C. nalidixic acid, out which, excluding all strains Ps. pyocyanea, 80% were found in to be range 32,ug./ml. or less (Table our 5). In experience organisms in this range found have been to be responsive to treatment. range In 64 psg./ml. re were 5 organisms, one only which appeared during period rapy and subsequently disappeared treatment. after 14 out 21 Ps. pyocyanea were in range > 256,ug./ml. and se were to be considered highly resistant. Even those 2 strains Ps. pyocyanea which were found to be in 32 to 64 jug./ml. range soon acquired to nalidixic resistance acid. Bacteriological Clearance: We define logical bacterio- clearance as state where re growth is on no plate culture urine two specimens for consecutive days. On first day 10 out rapy 16 patients had exclusively organisms sensitive in ir urine, eir one or two in number; or 6 patients had organisms multiple which were a mixture sensitive resistant and strains. The sensitive organisms E. coli were and Proteus, 90% which were up by cleared 4th day (i.e. 72 hours after One rapy). was cleared up on 5th day and on 7th anor day after rapy. None sensitive initially organisms acquired resistance but in patient one clearance was associated with ment replace- by emergent strains. It should be that mentioned some discrepancy will be found initial between sensitivity chart, presented in Table 3 and clearance presented here. This could be explained by fact that paraplegic are bladders ten severely diseased and flora, bacterial cultured from urine vary from day to

6 506 POSTGRADUATE MEDICAL JOURNAL August, 1965 TABLE 6 COMPLETE BACTERIOLOGICAL CLEARANCE IN RELATION TO THE DURATION OF THE DISEASE Duration Paraplegia Total No. Patients Completely Cleared Not Cleared 3 months or less months months years years 1 1 TOTAL TABLE 7 EMERGENT ORGANISMS DURING THERAPY WITH NALIDIXIC ACID IN 7 PATIENTS Sensitive Strains Resistant Strains No. Development Which were Where Organisms strains initially sensitivity Clearance resistance resistant was not done Ps. pyocyanea Strep. faecalis 4 4 E. coli 1 1 A. aerogenes 1 1 Staphylococcus albus 3 3 Atypical coliforms Haem. Strep. 1 1 TOTAL day. Culture and subsequent sensitivity tests done on a specimen urine take two days before results can be studied and thus organisms noted on a prerapy culture may be slightly different to those noted on first day rapy. Complete bacteriological clearance was achieved in 9 out 16 patients and or 7 did not clear up. A relationship has been shown between duration disease and clearance rate (Table 6). There is a better chance clearing infection in those patients with a recently diseased bladder than in those who have had disease for 1-5 years or longer. Presence cater has not been found to delay clearance sensitive organisms, though emergence infection or re-infection is quick in those cases. This opinion is based on fact that 12 out 16 patients had caters. Re-infection: This was noted in all 9 cases after complete bacteriological clearance. 3 were re-infected within 1st and 3 in 2nd week after completion rapy. The infecting organisms were sensitive to nalidixic acid in many cases. Emergent Organisms: During rapy with nalidixic acid 21 different strains organisms emerged in urine 7 patients (Table 7), se organisms appearing during rapy but before clearance initial organisms. Only one se, an atypical coliform, was sensitive to nalidixic acid. The rest were all resistant. Six patients out se seven had mixed infections sensitive and resistant strains and only one had purely sensitive strains initially. Automatic Clearance: Automatic clearance resistant organisms present initially or emerging afterwards, during or after rapy was found in 7 patients. 25 such organisms were isolated. 20 cleared up within first four weeks after appearance and or five cleared up after 6-8 weeks. This was noted when a follow up culture urine was done on each patient at 1-4 weeks interval. It should be mentioned that clearance resistant organisms was ten associated with replacement by a fresh organism, eir sensitive or resistant to nalidixic acid. The automatic clearance may be attributed to excess secretion urine in paraplegics who are always advised to drink more to avoid stone formation. Clinical Assessment: Out 16 patients, 14 had marked improvement in macroscopic picture ir urine, and 9 se 14 patients had a complete clearance maintained for 1-5 weeks or longer after completion rapy. Side effects were few and mild. Nausea, skin rash, weakness, dizziness for one day, and diarrhoea were noted in 4 patients. The condition subsided quickly, and only in one case who had diarrhoea, was drug discontinued, and this patient has been excluded from this series. Discussion Assays nalidixic acid in serum and urine healthy volunteers have been undertaken by Deitz and ors (1962). Their findings show that major portion drug is excreted through kidneys and is present for 8 hours

7 August, 1965 GIBBON, BENSTEAD AND MISRA: Nalidixic Acid 507 after administration. Buchbinder and ors (1962) administered nalidixic acid, 1 g. q.i.d. for 3 days to 6 cases pyelonephritis, and found serum levels ranging from 3.9 to 31.2 jug./ml. (mean value 6.8,ug./ml.), and urine levels from 62.5 to 500,ug./ml. (mean value 125 zg./ml.). Against se values we found mean concentrations 10.7 and 92.6 ug. /ml. in plasma and urine respectively. The significance mean plasma concentration nalidixic acid as found in this trial, and its relevance to parenchymatous lesions kidney and or tissues has yet to be elucidated. In this trial we found that drug level attained its height between 2nd and 4th hour after rapy in majority cases and diminished after that, although a fairly high concentration was still present at end 8th hour. Moreover, when continuous rapy was maintained about 90% urine samples taken after first day showed a concentration higher than 32 /&g./ml. irrespective time collection which varied from 2 to 5 hours after administration. Comparison with minimum inhibitory concentration shows that 80% sensitive Gram-negative bacteria in urine had M.I.C.'s 32 gg./ml. or lower. These bacteria were thus susceptible to nalidixic acid. Marked individual variation in concentration drug both in urine and plasma was noted in different patients and in same patient at different times; this has also been found by Deitz and ors (1962) and Buchbinder and ors (1962). Our results regarding minimum inhibitory concentration are comparable with those Barlow (1963) except that most his sensitive strains were limited to a M.I.C. 16,ug./ml. whereas in our experience y extended to 32,ug./ml. A great significance cannot be attached to this variation since two dilutions are so close to each or. Ps. pyocyanea, as usual, was found to be resistant to nalidixic acid in most cases, only two out 21 strains being found in 32 ug./ml. range. These two acquired resistance quickly. We have noted slightly different results in disc sensitivity test in vitro, compared to that Thompson and Rae (1964) who found chloramphenicol to be more effective against E. coli than nalidixic acid. In our experience about 90% E. coli and Proteus spp. were sensitive to nalidixic acid whereas only about 66% E. coli and 55% Proteus spp. were sensitive to chloramphenicol. The probable explanation is that most se paraplegic patients have had chloramphenicol at intervals before this trial and this has caused a number organisms to build resistance against it. Our results agree with findings Slade (1963), Buchbinder (1963), Barlow (1963), Thompson and Rae (1964) and Lishman and Swinney (1963) who showed that nitrurantoin, sulphonamides and tetracyclines were less effective against E. coli than nalidixic acid. Ward-McQuaid and ors (1963) found nalidixic acid to be as effective against Proteus spp. as chloramphenicol and nitrurantoin, but less effective than kanamycin. We, however, found nalidixic acid to be more effective against Proteus than chloramphenicol and nitrurantoin. Our findings agreed with se authors regarding greater effectiveness kanamycin. Lishman and Swinney (1963) have stated that nalidixic acid is more effective against A. aerogenes, but in our experience A. aerogenes was equally sensitive to nalidixic acid, chloramphenicol and tetracycline. and slightly more sensitive to kanamycin. From bacteriological study we found 9 out 16 patients were completely cleared ir organisms. Re-infection in all se cases was rapid and this is understandable considering effect indwelling caters on bladders paraplegics. Automatic clearance resistant strains was noted in 7 patients though ten new organisms emerged in ir place. Free and excess urine secretion due to ample fluid intake will explain this phenomenon. Patients who had no caters were found to maintain clearance for a slightly longer period. The cure rate in this trial (9 out 16) i.e. 56% was better than those published by or authors on chronic urinary infections, Rhoads, Billings and O'Conor (1952); Garrod, Shooter and Curwen (1954); Kass (1955); and Turck, Browder, Lindemeyer, Brown, Anderson and Petersdorf (1962). Our results were as good as those reported by Ward-McQuaid and ors (1963) but cure rate in Barlow's series (1963) was better than ours. Eighty-eight per cent sensitive E. coli and Proteus were found to be cleared within 72 hours rapy, remainder taking 5-7 days to clear up Ḟrom this we were able to suggest that a 5 day course nalidixic acid, 1 g. q.i.d. should be sufficient to clear up sensitive coliforms and Proteus in about 90% cases. A urine culture on 5th day will show bacteriological state disease and if clearance has still not been achieved drug should be continued. Summary A study plasma and urine concentrations nalidixic acid was carried out in 16 paraplegic patients with urinary tract infections who were treated with drug. Of urine samples, 90% had a concentration nalidixic acid greater than 32 usg./ml. This was correlated with minimum inhibitory concentrations all Gram-negative bacteria isolated in trial. 80% se bacteria had M.I.C.'s 32 ug. /ml. or less, and were thus susceptible to nalidixic acid. A comparative study activity or chemorapeutic drugs commonly used in urinary infections was carried out. Against E. coli and Proteus spp. nalidixic acid was found to be more effective than all or drugs tested

8 508 POSTGRADUATE MEDICAL JOURNAL August, 1965 except for kanamycin, but relatively ineffective against Pseudomonas. Nine 14 patients who had improvement in macroscopic picture ir urine had complete clearance which was maintained for 1-5 weeks after cessation rapy. Side-effects were few and mild. Our opinion nalidixic acid is that it is a safe antibacterial agent, clears organisms sensitive to it quickly, and can be administered repeatedly without serious toxic effect. We are grateful to Mr. E. Brown and Mr. A. Robertson Winthrop Laboratories, and Mr. M. C. Willcox for ir invaluable technical assistance. We wish to thank nursing staff Promenade Hospital for ir co-operation, Mr. H. Hallows and Southport and District Hospital Management Committeee for ir administrative help, and Dr. R. A. Miley and Mr. D. W. Sharp Clinical Evaluation Unit Bayer Products Company for ir advice and guidance. REFERENCES BARLOW, A. M. (1963): Nalidixic Acid in Infections Urinary Tract; Laboratory and Clinical Investigitions, Brit. med. J., ii, BUCHBINDER, M., WEBB, J. C., ANDERSON, L. V., and MCCABE, W. R. (1962): Laboratory Studies and Clinical Pharmacology Nalidixic Acid (Win. 18, 320). Antimicrobial Agents and Chemorapy p. 308 (American Society for Microbiology, Michigan). CARROLL, G. (1963): Negram (Nalidixic Acid): a new Anti-microbial Chemorapeutic Agent, J. Urol. (Baltimore), 90, 476. DEITZ, W. E., FROELICH, E. J., and BAILEY, J. H. (1962): Unpublished data in files Sterling Winthrop Research Institute. GARROD, L. P., SHOOTER, R. A., and CURWEN, M. P. (1954): The Results Chemorapy in Urinary Infections, Brit. med. J., ii, JAMESON, R. M., and SwINNEY, J. (1963): A Clinical Trial Treatment Gram-negative Urinary Infections with Nalidixic Acid, Brit. J. Urol., 35, 122. KASS, E. H. (1955): Chemorapeutic and Antibiotic Drugs in Management Infections Urinary Tract, Amer. J. Med., 18, 764. LESHER, G. Y., FROELICH, E. J., GRUETT, M. D., BAILEY, J. H., and BRUNDAGE, R. P. (1962): 1, 8- Naphthyridine Derivatives, a New Class Chemorapeutic Agents, J. Med. Pharm. Chem., 5, LISHMAN, I. V., and SWINNEY, J. (1963): Studies a New Antibacterial Agent, Nalidixic Acid (Win. 18, 320). A Report its Use in 60 Cases Urinary Tract Infection, Brit. J. Urol., 35, 116. MCCABE, E. S. (1963): Resistant Infections Urinary Tract, with Special Reference to a New Urinary Antiseptic and Pyelonephritis Lenta, J. Amer. Geriat. Soc., 11, 975. MCCHESNEY, E. W., FROELICH, E. J., LESHER, G. Y., CRAIN, A. V. R., and Rosi, D. (1964): Absorption, Excretion, and Metabolism a New Antibacterial Agent, Nalidixic Acid, Toxicol. appl. Pharmacol., 6, 292. MCGEACHIE, J., and KENNEDY, A. C. (1963): Simplified Quantitative Methods for Bacteriuria and Pyuria, J. clin. Path., 16, 32. RHOADS, P. S., BILLINGS, C. E., and O'CONOR, V. J. (1952): Antibacterial Management Urinary Tract Infections, J. Amer. med. Assoc., 148, 165. SLADE, D. A. (1963): A Clinical Trial Nalidixic Acid (Negram, Win. 18,320) in Thirty-three Patients with Urinary Infections Treated in General Practice, Brit. J. Urol., 35, 125. THOMPSON, R. E. M., and RAE, J. (1964): Negram (1 - ethyl methyl - 1, 8 - naphthyridine-4-one - 3- carboxylic Acid): A new Antibacterial Agent for Treatment Urinary Infection. Report a Trial in General Practice, Brit. J. Urol., 36, 42. TURCK, M., BROWDER, A. A., LINDEMEYER, R. I., BROWN, N. K., ANDERSON, K. N., and PETERSDORF, R. G. (1962): Failure Prolonged Treatment Chronic Urinary-tract Infections with Antibiotics, New Engl. J. Med., 267, 999. WARD-MCQUAID, J. F. N. C., JICHLINSKI, D., and MACIS, R. (1963): Nalidixic Acid in Urinary Infections, Brit. med. J., ii, WATERWORTH, P. M. (1962): A Misapplication Sensitivity Test Mandelamine Discs, J. med. Lab. Technol., 19, 163. A CLINICAL TRIAL WITH NALIDIXIC ACID ON 22 ACUTE AND CHRONIC URINARY TRACT INFECTIONS WITH FOLLOW-UP FOR I-5 MONTHS NALIDIXIc acid is one a series 1, 8-naphthyridine derivatives. The chemistry, pharmacology and toxicology have been detailed elsewhere, Lishman and Swinney (1963) and Ward-McQuaid, Jichlinski and Macis (1963). In a number clinical trials published recently this chemorapeutic agent was shown to be very effective against Gram-negative organisms in urinary tract infec- G. C. MISRA, M.B., B.S. M. C. WILLCOX, F.I.M.L.T. Research Fellow Chief Technician Liverpool Regional Paraplegic Centre, Southport. tions, Lishman and Swinney (1963), Jameson and Swinney (1963), Slade (1963), Barlow (1963), Ward- McQuaid and colleagues (1963), Thompson and Rae (1964), McCabe (1963), Carroll (1963) and Gibbon, Benstead and Misra (1965). On basis this information we investigated 22 acute and chronic cases urinary tract infection with follow-up for 1-5 months.