ABSTRACT
Objectives: Staphylococcus aureus(S.aureus) is regarded as an important aetiological agent of various human infections. Fluoroquinolonesare routinely used in the chemotherapeutic management of these infections; nonetheless, in recent years, a growing rate of resistance to these drugs has been reported worldwide. The aims of this study were to isolate and discover the prevalence of plasmid-mediated (qnrA, qnrB, and qnrS) genes among the quinolone-resistant clinical S. aureusisolates in Bayelsa State, Nigeria.Methods: A total of 25 (31.25%) clinical isolates of S. aureuswere collected from hospitalized patients. The bacterial isolates were identified through standard laboratory protocols and further confirmed using the API Staph system (bioMérieux, France) test strips. The antimicrobial susceptibility and minimum inhibitory concentration (MIC) were determined by the standard disk diffusionand serial dilutions methods respectively. Polymerase chain reaction (PCR) was used for detecting qnrA, qnrB, and qnrSgenes.Results: Of the 25 S. aureus isolates, 19(76.00%) were resistant to ampicillin-cloxacillin, while 14 (56.00%) each were resistantto norfloxacin and Amoxicillin, 13 (52.00%) each to gentamicin and erythromycin, 11 (44.00%) were resistant to streptomycin, rifampicin and ciprofloxacin, respectively. The resistance pattern among the isolates to chloramphenicol and levofloxacin were 10 (40.00%) and 7 (28.00%) respectively. All the eleven ciprofloxacin resistant were high-level (1000 μg/mL) resistance isolates and only one (9.00%) of these isolates was positive for the qnrBgene.Conclusion: The study results were indicative of the presence of low frequency of qnrgenes among the clinical isolates of S. aureusin Yenagoa, indicating that other mechanisms are employed in resisting to these fluoroquinolones. This, however, emphasizes the need for establishing discreet policies associated with infection-control measures in hospital settings
ABSTRACT
Turtle-borne Salmonella enterica owns significance as a leading cause in human salmonellosis. The current study aimed to determine the quinolone susceptibility and the genetic characteristics of 21 strains of S. enterica subsp. enterica isolated from pet turtles. Susceptibility of four antimicrobials including nalidixic acid, ciprofloxacin, ofloxacin, and levofloxacin was examined in disk diffusion and MIC tests where the majority of the isolates were susceptible to all tested quinolones. In genetic characterization, none of the isolates were positive for qnr or aac(6')-Ib genes and no any target site mutations could be detected in gyrA, gyrB, and parC quinolone resistance determining regions (QRDR). In addition, neighbor-joining phylogenetic tree derived using gyrA gene sequences exhibited two distinct clads comprising; first, current study isolates, and second, quinolone-resistant isolates of human and animal origin. All results suggest that studied strains of S. enterica subsp. enterica isolated from pet turtles are susceptible to quinolones and genetically more conserved with regards to gyrA gene region.
Subject(s)
Animals , Humans , Ciprofloxacin , Diffusion , Levofloxacin , Nalidixic Acid , Ofloxacin , Quinolones , Salmonella enterica , Salmonella Infections , Salmonella , Trees , TurtlesABSTRACT
SUMMARY Stenotrophomonas maltophilia contains a novel chromosomally-encoded qnr gene named Smqnr that contributes to low intrinsic resistance to quinolone. We described Smqnr in 13 clinical isolates of S. maltophilia from two Brazilian hospitals, over a 2-year period. The strains were identified by API 20 NE (bioMérieux, France). Susceptibility by microdilution method to trimetroprim/sulfamethoxazole, ciprofloxacin, levofloxacin, minocycline, ceftazidime, chloramphenicol and ticarcillin/clavulanate was performed according to CLSI. PCR detection of Smqnr gene was carried out. The sequence of Smqnr was compared with those deposited in GenBank. Pulsed-field gel electrophoresis (PFGE) of all strains was performed. Thirteen Smqnr positives isolates were sequenced and three novel variants of Smqnr were identified. All 13 Smqnr isolates had distinguishable patterns by PFGE. This is the first report of Smqnr in S. maltophilia isolated in Brazil. .
RESUMO S. maltophilia contem um novo gene qnr cromossômico denominado Smqnr que contribui para baixa resistência intrínseca a quinolonas. Descrevemos Smqnr em 13 isolados clínicos de S. maltophilia de dois hospitais brasileiros, ao longo do período de dois anos. Os isolados foram identificados pela API 20 NE (bioMérieux, França). Susceptibilidade pelo método de microdiluição dos seguintes antibióticos trimetroprim/sulfametoxazol, ciprofloxacina, levofloxacina, minociclina, ceftazidima, cloranfenicol e ticarcilina/clavulanato foi realizada segundo o CLSI. Detecção do gene de Smqnr foi realizada por PCR. A sequência de Smqnr foi comparada com aquelas depositadas no GenBank. Foi realizada eletroforese em gel de campo pulsado (PFGE) de todos os isolados. Treze isolados contendo Smqnr foram sequenciados e identificados três variantes do gene Smqnr. Todos os 13 isolados de Smqnr apresentaram diferentes padrões por PFGE. Este é o primeiro relato de Smqnr em isolados de S. maltophilia no Brasil. .
Subject(s)
Humans , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , Drug Resistance, Bacterial/genetics , Stenotrophomonas maltophilia/genetics , Amino Acid Sequence , Brazil , Electrophoresis, Gel, Pulsed-Field , Microbial Sensitivity Tests , Molecular Sequence Data , Polymerase Chain Reaction , Stenotrophomonas maltophilia/drug effects , Stenotrophomonas maltophilia/isolation & purificationABSTRACT
OBJECTIVE: This is to investigate the implication of fluoroquinolone usage in veterinary practice and the food chain system. SUBJECTS AND METHODS: Five hundred isolates of commensal E coli were recovered from the faeces of apparently healthy cattle in Ado-Ekiti, Nigeria. The susceptibility of the bacteria was tested using standard laboratory procedures. Polymerase chain reaction (PCR) was carried out to detect the presence of qnrA and qnrB genes, which were selected on the basis of their fluoroquinolone-resistant patterns. RESULTS: The agar disc diffusion technique revealed that the representative isolates showed multiple fluoroquinolone-resistance and this formed the basis for their selection for PCR amplification. The PCR revealed that ten of the 17 quinolone-resistant representative isolates showed distinct bands which are specific for the qnrB gene; in addition, only one strain of the 20 representative isolates of commensal E coli carried plasmids on which the qnrA gene was detected. CONCLUSION: This study has confirmed that plasmid-mediated quinolone resistance is a possible mechanism among the fluoroquinolone-resistant commensal E coli isolated from faeces of apparently healthy cattle in the study location.
OBJETIVO: El propósito de este trabajo es investigar las implicaciones del uso de las fluoroquinolonas en la práctica veterinaria y el sistema de la cadena alimentaría. SUJETOS Y MÉTODOS: Quinientos aislados de E Coli comensales fueron obtenidos de las heces de ganado ostensiblemente sano en Ado-Ekiti, Nigeria. Se sometió a prueba la susceptibilidad de las bacterias usando los procedimientos de laboratorio normales. Se llevó a cabo una reacción en cadena de la polimerasa (RCP) a fin de detectar la presencia de genes qnrA y qnrB, los cuales fueron seleccionados sobre la base de sus patrones de resistencia a la fluoroquinolona. RESULTADOS: La técnica de difusión con disco en agar reveló que los aislados representativos mostraban resistencia múltiple a la fluoroquinolona, lo cual constituyó la base para su selección a fin de amplificar la RCP. La RCP reveló que 10 de cada 17 asilados representativos de la resistencia a la quinolona, mostraban bandas claramente específicas del gen qnrB. Además, sólo una cepa de 20 aislados representativos de las E Coli portaba plásmidos en los que el gen qnrA fue detectado. CONCLUSIÓN: Este estudio confirmó que la resistencia a la quinolona mediada por plásmidos, es un posible mecanismo entre las E Coli comensales aisladas de la haces del ganado sano en la localidad del estudio.
Subject(s)
Animals , Cattle , Drug Resistance, Bacterial/genetics , Escherichia coli/genetics , Fluoroquinolones/pharmacology , Escherichia coli/drug effects , Nigeria , PlasmidsABSTRACT
Objective To study on plasmid-mediated quinolone-resistant in Escherichia coli strains isolated from fecal samples of chicken and swine from the nine farms around our country.Methods Antimi-crobial susceptibility testing was carried out by broth microdilution testing,gyrA,gyrB,parC,qnr and aac (6')- Ⅰ b-cr were examined by PCR,and the products were sequenced.Conjugation experiment was carried out to proved that the plasmid-mediated quinolone resistance was transferable.Results In the total 818 animal isolates,qnr and aac genes were detected in 38 (4.6%) and 75 (9.2%) strains.The qnrA,qnrB,and qnrS genes were detected in 1 (0.1%),9 (1.1%) and 28 (3.4%) of the isolates.All isolates were negative for qnrC,qnrD genes.Conclusion There is a close relationship between high level quinolone resistance and plasmid-mediated quinolone resistance.The results of the current study highlight food-producing animals as a potential reservoir of antimicrobial-resistant bacteria and clinically important resistance genes.More attention should be paid to the surveillance of such strains.