One hundred eight Listeria monocytogenes food isolates from four cities in Colombia and previously confirmed by multiplex polymerase chain reaction were characterized for antimicrobial susceptibility. Isolates were evaluated against 17 antimicrobials contained in the MICroSTREP plus(®)3 panel (MicroScan system). Susceptibility found for ampicillin, amoxicillin/clavulanic acid, and chloramphenicol was 100%, whereas it was 98% for other antimicrobials such as trimethoprim/sulfamethoxazole, 97% for azithromycin, 92% for vancomycin, 90% for erythromycin, 86% for tetracycline, 84% for penicillin, 70% for ciprofloxacin, 57% for rifampin, 56% for meropenem, and 32% for clindamycin. Natural resistance to cephalosporins was confirmed in all cases, and 16% of isolates were nonsusceptible to penicillin. Using Staphylococcus spp. or Enterococcus spp. breakpoints, 48% of isolates displayed multidrug resistances, and the major resistance phenotypes were against rifampin, clindamycin, ciprofloxacin, azithromycin, and erythromycin. Colombian food isolates displayed high resistance to clindamycin, meropenem, rifampin, and ciprofloxacin (30%-65%), and the primary drugs of choice against listeriosis remain effective for most of isolates (84%).

Antimicrobial susceptibility of Listeria monocytogenes food isolates from different cities in Colombia.

We developed a monoclonal antibody (mAb) to detect norfloxacin (NOR) using a novel hapten by introducing an amino group via amido linkage into the piperazine ring of NOR. The sensitivity of an indirect competitive enzyme-linked immunosorbent assay (icELISA) based on this mAb showed an improved IC50 value from 1.18 to 0.12 ng/mL and the limit of detection from 0.37 to 0.05 ng/mL by using a heterologous coating (pazufloxacin coupled to ovalbumin). The recovery rate for NOR in milk ranged from 77.3% to 117.8%. Cross-reactivity (CR) experiments showed good CR with nine common fluoroquinolone analogs: pefloxacin, lomfloxacin, ciprofloxacin, enrofloxacin, dafloxacin, sparfloxacin, ofloxacin, marbofloxacin and flumequine. Furthermore, based on this antigen–antibody combination, an immunochromatographic strip with cut-off value of 1 ng/mL was developed. Given their good sensitivity and CR, the developed icELISA and immunochromatographic strip could be useful for detection of NOR and its analogs in milk.

https://www.tandfonline.com/doi/pdf/10.1080/09540105.2016.1263987

Development of an icELISA and immunochromatographic strip for detection of norfloxacin and its analogs in milk

Salmonella isolated from chicken carcasses from a slaughterhouse in the state of Mato Grosso, Brazil: antibiotic resistance profile, serotyping, and characterization by repetitive sequence-based PCR system.

Introduction: Listeria species are susceptible to most antibiotics. However, over the last decade, increasing reports of multidrug-resistant Listeria spp. from various sources have prompted public health concerns. The objective of this study was to characterize the antibiotic susceptibility of Listeria spp. and the genetic mechanisms that confer resistance. Methodology: Forty-six Listeria spp. isolates were studied, and their minimal inhibitory concentrations of antibiotics were determined by microdilution using Sensititre standard susceptibility MIC plates. The isolates were screened for the presence of gyrA, parC, lde, lsa(A), lnu(A), and mprF by PCR, and the amplified genes were sequenced. Results: All isolates were susceptible to penicillin, ampicillin, tetracycline, erythromycin, and carbapenems. Resistance to clindamycin, daptomycin, and oxacillin was found among L. monocytogenes and L. innocua, and all species possessed at least intermediate resistance to fluoroquinolones. GyrA, parC, and mprF were detected in all isolates; however, mutations were found only in gyrA sequences. A high daptomycin MIC, as reported previously, was observed, suggesting an intrinsic resistance of Listeria spp. to daptomycin. Conclusions: These results are consistent with reports of emerging resistance in Listeria spp. and emphasize the need for further genotypic characterization of antibiotic resistance in this genus.

/pdf/characterization-of-antibiotic-resistance-in-listeria-spp-51zmxdqv00.pdf

Characterization of antibiotic resistance in Listeria spp. isolated from slaughterhouse environments, pork and human infections.

Switchable hydrophilicity solvent membrane-based microextraction: HPLC-FLD determination of fluoroquinolones in shrimps.

Fluoroquinolones are antimicrobial agents frequently used in poultry production and in human medicine. The use of such substances must comply with safety criteria, including withdrawal periods, doses, and treatment duration, as their misuse and abuse may cause bacterial resistance and the presence of residues in edible tissues. Consequently, the consumption of animal products with fluoroquinolone residues may result in the transmission of resistant bacteria. In addition, if residues are beyond the acceptable levels, fluoroquinolone active metabolites are harmful to human health. This article presents a review on the use of antimicrobials of the fluoroquinolone class in poultry production, focusing on the development of bacterial resistance to these drugs and the presence of their residues in poultry products.

https://www.scielo.br/pdf/rbca/v17n1/1516-635X-rbca-17-01-00001.pdf

Fluoroquinolones in Industrial Poultry Production, Bacterial Resistance and Food Residues: a Review

With the increasing use of antibiotics as growth promoters and even for therapeutical purposes on breeding of food-producing animals, there is the worldwide interest related to the ingestion of antibiotical residues on food and their effects on human health. The ingestion of food containing antibodies residues can cause bacterial resistence to the antibodies usually used on human therapies, what difficult the treatment of human infectious illnesses. Antibiotic sensitivity test was realized on Listeria spp. Strains, which were isolated from bovine meat samples, according to the National Committee for Clinical Laboratory Standards (NCCLS), 2003. According to the finding results, all isolated strains showed resistance to gentamicine, cefoxitine, ampicyline, clindamicine, oxacycline and sulfazotrim. L. innocua isolated strains showed resistance to gentamicine, cefoxitine, tetracycline, vancomicine, oxacycline and clindamicine.

https://www.revistas.usp.br/bjvras/article/download/26708/28491

Resistência antimicrobiana de bactérias do gênero Listeria spp: isoladas de carne moída bovina

This study investigated the efficiency of an enrofloxacin ELISA test kit to detect the presence of enrofloxacin residues in broiler tissues compared with LC-MS/MS. Broiler tissues from 72 samples consisting of 60 breast muscle, six pools of livers (500 g each) and six pools of kidneys (500 g each) were obtained from six different slaughterhouses. Breast muscle from 10 carcasses and pools of livers and kidneys from approximately 200 carcasses of the same flock were collected from each slaughterhouse. ELISA and HPLC were used to identify and quantify the contamination of the samples with enrofloxacin. A total of 72% of the analysed samples contained enrofloxacin residues detected by the ELISA and 22.2% were detected by LC-MS/MS. The mean values of enrofloxacin contamination found in chicken breast by ELISA and HPLC were 8.63 and 12.25 μg kg(-1), respectively. None of the samples exceeded the maximum limit of 100 μg kg(-1) by both methods set by the European Union as well as the Brazilian Agriculture Ministry. All positive samples for enrofloxacin residues detected by LC-MS/MS were also positive by ELISA. These data confirm the efficiency of the ELISA test, and suggest its use as a screening method for enrofloxacin residues in poultry tissues due to its quick results, low price and ease of applicability.

Investigation of enrofloxacin residues in broiler tissues using ELISA and LC-MS/MS

Chicken feet bacteriological quality at 4 steps of technological processing.

Listeria monocytogenes is commonly found on nature and on intestinal tract of animals, therefore contamination of carcass and cut piece of meat is common during slaughter and industrial processing. This microrganism is con sidered as an emergent pathogen, which is capable to provoke listeriosis in humans through in gestion of contaminated food by Listeria spp. The listeriosis is a zoonosis of great importa nce on public health, considering that it may cause abortion, sepsis and meningitis. Pregnant wom en, children, the old and immunodeficient patients form the risk group of peo ple to listeriosis. The importance of

Raquel Gouvêa

Papers

Fluoroquinolones in Industrial Poultry Production, Bacterial Resistance and Food Residues: a Review

Resistência antimicrobiana de bactérias do gênero Listeria spp: isoladas de carne moída bovina

Investigation of enrofloxacin residues in broiler tissues using ELISA and LC-MS/MS

Chicken feet bacteriological quality at 4 steps of technological processing.

Importância da listeria monocytogenes em alimentos de origem animal. importance of listeria monocytogenes on foods from animal origin.