# US 5,350,680 A · Cephalosporinase testing agent

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- Number: US 5,350,680 A
- Document ID: US5350680A
- Status: Granted
- Kind: A
- Application number: 07/976,993
- Filed: 1993-02-02
- Granted: 1994-09-27
- Earliest claimed: 1990-12-21
- Assignees: Showa Yakuhin Kako Co., Ltd.
- Inventors: Matsuhisa Inoue; Akira Sakai
- Web page: https://patentgrep.com/patent/US5350680A

## CPC

- C12Q 1/34: involving hydrolase
- G01N 2333/986: acting on amide bonds in cyclic amides (3.5.2), e.g. beta-lactamase (penicillinase, 3.5.2.6), creatinine amidohydrolase (creatininase, EC 3.5.2.10), N-methylhydantoinase (3.5.2.6)
- G01N 2415/00: Assays, e.g. immunoassays or enzyme assays, involving penicillins or cephalosporins
- Y10S 435/81: Packaged device or kit
- Y10S 435/975: Kit
- C12Q: MEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS (immunoassay G01N33/53); COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A cephalosporinase testing agent comprising a cephalosporin antibiotic, a penicillinase inhibitor in an amount of 20% by weight or less based on the weight of the cephalosporin-antibiotic, and a pH indicator which may be bromcresol purple is provided. A cephalosporinase producing bacteria can be judged by smearing a sample containing bacteria to be tested on the testing agent and observing the color tone change. According to this agent, cephalosporinase-active penicillinase producing bacteria are judged cephalosporinase-negative owing to the action of the penicillinase inhibitor, which may be clavulanic acid. Therefore, since only cephalosporinase producing bacteria are judged cephalosporinase-positive, this agent enables error free judgment.

## Claims

### Claim 1

A cephalosporinase testing agent comprising a cephalosporin antibiotic selected from the group consisting of cefalexin, cefaclor, cefaloglycin, cefadroxil, cefatrizine, cefamandole, cefradine, cefroxadine, cefapirin, cefalotin, cefaloridine, cefotiam, ceftezole, cefazolin and cefacetoril, a penicillinase inhibitor in an amount of 0.5 to 5% by weight based on the weight of the caphalosporin antibiotic, and a pH indicator.

### Claim 2 (depends on 1)

The cephalosporinase testing agent according to claim 1 further comprising a pH adjusting agent.

### Claim 3 (depends on 1)

The cephalosporinase testing agent according to claim 1 supported on a substrate by impregnating the substrate with the testing agent in the form of solution.

### Claim 4 (depends on 1)

The cephalosporinase testing agent according to claim 1, wherein the penicillinase inhibitor is clavulanic acid.

### Claim 5 (depends on 1)

The cephalosporinase testing agent according to claim 1, wherein the pH indicator has a transition interval in the range of from pH 5 to pH 9.

### Claim 6 (depends on 1)

The cephalosporinase testing agent according to claim 1, wherein the penicillinaset inhibitor is clavulanic acid and the pH indicator is bromcresol purple.

### Claim 7 (depends on 1, 2, 3, 4, 5, 6)

A kit for detecting a cephalosporinase comprising a reference testing agent including a penicillinase inhibitor and a pH indicator and the beta-lactamase testing agent according to any one of claims 1 to 6.

### Claim 8

A method for testing a sample from the presence of a cephalosporinase which comprises the steps of (a) smearing a sample comprising bacteria to be tested on a cephalosporinase testing agent comprising a cephalosporin antibiotic selected from the group consisting of cefalexin, cefaclor, cefaloglycin, cefadroxil, cefatrizine, cefamandole, cefradine, cefroxadine, cefapirin, cefalotin, cefaloridine, cefotiam, ceftezole, cefazolin and cefacetoril, a penicillinase inhibitor in an amount of 0.5 to 5% by weight based on the weight of the cephalosporin antibiotic, and a pH indicator, and (b) observing any change of color of the testing agent.