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Aim:  To determine the antimicrobial resistance of the Japanese probiotics available in the market without a pharmacist’s supervision. Methods and Results:  A total of 43 isolates were obtained from 40 samples of probiotics (30 dairy products and 10 products in tablet form). Isolates were identified using 16S rRNA gene sequencing and tested for their susceptibility to 14 antimicrobials. They were screened using PCR for some antibiotic resistance genes. Inactivation of cefepime, clarithromycin and vancomycin by different inocula of 11 strains was evaluated using the antibiotic inactivation bioassay. None of the dairy probiotics showed a level of constitutive resistance or carried inducible resistance genes, making them suitable to be administrated with macrolides. Among the probiotics in tablet form only Enterococcus faecium strains carrying the msrC gene showed an MIC90 of 4 μg ml−1. Extended‐spectrum β‐lactams, tetracyclines and ampicillin exhibited powerful germicidal activity against the vast majority of the probiotic strains. Conclusions:  There is a limited choice of the Japanese probiotics that can be administered with clinically used antibiotics. Significance and Impact of the Study:  Japanese probiotics are widely distributed all over the world. Through the findings of our study, we have attempted to provide guidance for clinicians interested in using the Japanese probiotics in combination with antibiotics.

ABSTRACT. During monitoring of raw milk samples from healthy cows for the presence of antibiotic resistant bacteria, one isolate of Klebsiella pneumoniae strain HUF-100 was found to be resistant to oxyimino-cephalosporins and aztreonam. It was found to carry a chromosomally-encoded extended-spectrum β-lactamase that has not been described previously, namely SHV-60. Thus, it must be expected that this strain will spread further among food-producing animals and thereby constitute a reservoir of this resistant strain and resistance gene that can transfer to and cause treatment problems for humans. The present study confirms the hypothesis that some of novel multiple antibiotic resistant zoonotic bacterial pathogens may initially emerge from food animals and reports, for the first time, this type of emergence in Japan.KEY WORDS: Klebsiella pneumoniae, milk, SHV β-lactamase.J. Vet. Med. Sci. 70(11): 1269-1272, 2008 Colonization of the udders of the healthy cows with multidrug-resistant zoonotic pathogens during lactation or dry periods is one of the most important threats affecting not only the dairy industry but also public health. Recently, sections of the population in developed nations have been misinformed by many sites on the internet and regard raw milk as more nutritious and better tasting than pasteurized milk [12]. Therefore, we conducted a study to monitor multidrug-resistant bacteria in the raw milk of California mastitis test negative healthy cows that had not received any antibiotics in their feed and that had not been treated with antibiotics for more than 3 months, factors not analyzed previously.Twenty milk samples were collected aseptically into sterile screw-capped bottles after discarding three streams of milk and were directly transported to the laboratory in an ice box. Twenty-five ml of individual milk samples was added to 225 ml of buffered peptone water and incubated at 37°C with agitation for 24 hr. Following incubation, the enriched samples were subcultured onto MacConkey agar plates and incubated for 24 hr at 35°C. An API-20E system (bioMérieux, Marcy l'Etoile, France) was used for biochemical identification of isolated strains. The characterized strains were tested for susceptibility to antimicrobials by disk diffusion and MIC methods using Muller-Hinton agar (Nissui Pharmaceutical Co., Tokyo, Japan) and MullerHinton broth (Oxoid), respectively, according to guidelines of the Clinical and Laboratory Standards Institute (CLSI, 2005) [6]. A strain identified as Klebsiella pneumoniae, KPHUF-100, exhibited an uncommon phenotype, suggesting the presence of an extended-spectrum β-lactamase (ESBL) with a spectrum extended to oxyimino-cephalosporins and aztreonam. MIC determination in the presence of a fixed concentration of clavulanic acid (4 µg/ml; β-lactamase production was first confirmed by isoelectric focusing that was performed in a 111 Mini IEF Cell apparatus (Bio-Rad Laboratories) on polyacrylamide gel in the presence of ampholines in the pH range 3.5-10. Broadrange pI markers (Bio-Rad...

The aim of this study was to address the prevalence and the molecular characteristics of antibiotic-resistant enteric bacteria isolated from one of the most popular types of Egyptian cheese. A total of 215 ampicillin-resistant enterobacterial isolates were obtained from 80 samples of Domiati cheese, and they were screened by PCR for a large pool of antibiotic resistance markers, including extended-spectrum beta-lactamases (ESBLs), class 1 and class 2 integrons, and plasmid-mediated quinolone resistance genes. It was determined that the most frequent mechanism of ampicillin resistance was from a TEM-1-type beta-lactamase. As well, SHV beta-lactamases, including SHV-1, SHV-25, and SHV-26, showed a high prevalence, and two novel SHV beta-lactamases, SHV-110 and SHV-111, were identified. Type CTX-M-14, OXY-1, OXA-1, and CMY-4 beta-lactamases were also detected in a few isolates. In addition, a novel AmpC beta-lactamase was detected that was designated CMY-41. Sequencing results of class 1 integrons revealed that the uncommon aminoglycoside resistance gene cassette aadA22 was found for the first time in an Escherichia coli strain. The other class 1 integrons harbored various common gene cassettes, including aadA1, aadA1a, aadA2, aadA12, dfr5, dfr7, dfr12, and dfr15. The only isolate that carried a class 2 integron contained dfrA1, sat2, and aadA1. Plasmid-mediated quinolone resistance determinants qnrS and qnrB showed a low prevalence. This study provides meaningful data on high antimicrobial resistance contained in Domiati cheese samples and reports for the first time the presence of beta-lactamases, plasmid-mediated quinolone resistance, and integrons in isolates from food of Egyptian animal origin.