Screening of rpsL mutations in streptomycin resistance gene of 104 strains of Yersinia pestis strains in south area of Qinghai Province by TaqMan-MGB fluorescent probe / 中国热带医学

@#Abstract: Objective To investigate the current status of streptomycin resistance of Yersinia pestis caused by point mutations of rpsL gene in Qinghai, so as to provide theoretical basis for precise clinical medication and prevention of drug resistance of human plague outbreak in South area of Qinghai Province in the future. Methods A total of 104 representative strains of Yersinia pestis collected from plague patients, vector insects and intermediate hosts in South area of Qinghai Province from 1957 to 2009 were screened, isolated and cultured by Hiss agar plates. The DNA of representative Yersinia pestis was extracted by sodium dodecyl sulfate lysis and phenol-chloroform method. The primers forward primer and reverse primer and TaqMan-MGB probes probe1 [FAM] and probe2 [VIC] were designed for the rpsL gene of streptomycin resistance gene in China. Real-time PCR with TaqMan-MGB fluorescent probe was used to detect the mutations of rpsL gene in streptomycin resistance locus of 104 strains of Yersinia pestis in South area of Qinghai Province. Results The FAM test results of 104 strains in South area of Qinghai Province were positive, corresponding to the detection of rpsL (128 : A ), RFU peak >1 000,negative <200. VIC test results of all tested strains were negative, corresponding to the detection of rpsL (128:G), RFU peak <200, positive >1 000. That is, no strains with rpsL gene mutation related to streptomycin resistance were found in the 104 strains of Yersinia pestis in Qingnan Province. Conclusion This study provides basic data on the distribution of streptomycin resistance of Yersinia pestis in South area of Qinghai Province, and lays a foundation for preventing the occurrence of drug resistance and clinical treatment of Yersinia pestis in South area of Qinghai Province.

Enumeration of Bacterial Isolates from Hands of Primary and Post Primary School pupils in Amai, Delta State

The presence of bacteria on the hands of fourty (40) school pupils from two different schools (Amai Primary and secondary School) in Amai, Delta State, was analysed. The reason was to enumerate bacteria isolated from hands of students. Swab samples were collected from hands of pupils in both schools of 20 students each of different sex groups. Microbiological methods was used for the isolation, enumeration and antibiotic test of the isolates. The results showed various isolates of Staphylococcus sp 56 (25.7%), Shigella sp 24 (9.7%), Staphylococcus epidermidis 32 (12.1%), Escherichia coli 41 (15.6%), and Enterococcus sp 36 (11.0%). Staphylococcus aureus 56 (25.3%) and Escherichia coli 41 (15.6%) were the most frequent isolates. The isolation of Shigella sp 24 (9.7%) and Enterococcus sp 36 (11.0%) is of great importance as the isolation of these organisms showed improper faecal wastes disposal around the school environment and also lack of proper clean up after using the convience by the pupils. Testing these isolates to few antibiotics, the isolates were susceptible to Pefloxacin, Gentamycin, Erythromycin, Chloramphenicol, Streptomycin, while resistant to Augmentin, Amoxicillin, and Ampiclox. This study revealed that the students hands were infested with pathogens due negligence of maintenance culture. Those in charge of schools like the principal are advised to keep soap and water for hand washing, while parents on their part should make available hand washing facilities for their children at home since it will add economic value to the society, why Government should enact laws that will make provision of washing hand amenities in all areas compulsory for individuals.

Detection of high-level aminoglycoside resistance by disc diffusion and e-test amongst the enterococcus species isolated from various clinical samples in a tertiary care hospital

Background: The emergence of Enterococcus species in causing nosocomial infections poses a therapeutic challenge to clinicians. Enterococci are intrinsically resistance to multiple antibiotics. Acquired resistance to commonly used antibiotics like Ampicillin, Vancomycin and Aminoglycosides have made the situation worse and difficult to treat serious Enterococcal infections. The present study aimed at detection of high-level aminoglycoside resistance by disc diffusion and E-test amongst the Enterococcus species isolated from various clinical samples in a tertiary care hospital.Methods: A total of 102 Enterococcus species isolated from various clinical samples and antimicrobial susceptibility was performed by Kirby Bauer disc diffusion method as per CLSI guidelines. E-test was done for all high level aminoglycoside resistance Enterococcus species isolated by disc diffusion test.Results: Among 102 isolates, 81 were E. faecalis, 18 were E. faecium and 3 were another Enterococcus. Their antimicrobial susceptibility pattern shows all isolates were sensitive to vancomycin, linezolid and teicoplanin with HLGR, HLSR detected in 40 and 38 isolates of E. faecalis, 17  and 13 isolates of E. faecium respectively by disc diffusion whereas by E-test it was detected in 44 and 40 in E. faecalis and 17 and 14 in E. faecium respectively. E. faecium is found to be more resistance to high level aminoglycoside than E. faecalis.Conclusions: Authors hereby conclude that Enterococci being the common cause of hospital acquired infections with their increasing resistance to multiple drugs and acquisition of HLAR; it must be routinely screened for various drugs to prevent drug resistance in hospital settings for serious Enterococcal infections.

Diameters of Perikarya in Different Regions of Rat Central Nervous System after Streptomycin and Kanamycin Intoxication

Introduction: Streptomycin and Kanamycin, an aminoglycosidic antibiotic, is known to destroy the ventral cochlear nuclei of brainstem in man. Ototoxicity is well known side effect of kanamycin, the effect on central nervous system in general and central auditory pathway in particular is still unclear. Subjects and Methods: Thirty albino rats were divided into three groups I, II and III of ten animals each. Group III was control. Group I and II received Streptomycin (30mg/Kg body weight) and kanamycin (400mg/kg body weight) intramuscular injections, daily for 3 weeks. Paraffin embedded sections of cerebellum, spinal cord, dorsal cochlear nucleus, inferior colliculus nucleus and auditory cortex were stained with haematoxylin and eosin stains and perikarya measured using slide and ocular micrometres. Results: Size of cerebellar Purkinje cells increased significantly in control rats for streptomycin and kanamycin intoxicated animals respectively. Ventral horn cells of spinal cord are affected highly significantly only by streptomycin. Vestibular nucleus also showed similar results i.e. neuronal body. Neurons of dorsal cochlear nucleus is affected significantly by both the drugs i.e. streptomycin and kanamycin. Conclusion: Streptomycin causes an increase in diameter of auditory cortical cells on other hand kanamycin led to highly significant decrement in size of cells of same region. Preferential affinity and differential effects were noticed. The latter throws some clues about mechanism of action.

Oscar Castro Zúñiga: el poeta vencido por la tuberculosis / Oscar Castro Zúñiga, the poet who succumbed to tuberculosis

The life of the renowned Chilean writer, Oscar Castro Zúñiga, was interrupted early, when he was 37 years old. He acquired tuberculosis during the epidemic in our country between the second half of the nineteenth century and the first half of the twentieth century. He developed the disease during a crucial stage in terms of diagnosis and treatment, coinciding with the end of the sanatorium stage and the first chemotherapeutic attempts. The symptoms and treatments of the disease in that age are described analyzing the letters, both written by himself and by people close to him and the biographies published during the historical and personal context of the artist.

Historical story on natural medicinal chemistry: Streptomycin / 中草药

Streptomycin isolated from microorganism is a major milestone in human history to beat tuberculosis, and guides the research of aminoglycoside antibiotics. As the second antibiotics which could be used in clinic after penicillin, the discovery of streptomycin owed much to the systematic research of Dr. Selman Abraham Waksman on microorganism in moil for more than 20 years and hard work of many scientists from different subjects. The systematic experimental method that found antibiotics was built by Dr. S A Waksman and the discovery of streptomycin greatly promoted the development of antibiotics in 1940s. This paper reviewed the study process of streptomycin development and the outstanding contributions of related scientists. At the same time, hoping to encourage the young scientists to work hard and make great contribution for the benefit of humanity. This is one of the series papers about historical story on natural medicinal chemistry.

Influence of antibiotic concentration on the integration frequency of resistance cassette in the integron / 中华检验医学杂志

Objective@#To observe the integration frequency of aadA2 resistance cassette at attI site of the integron under different concentration of streptomycin. @*Methods@#Class 1 integron with known gene sequence was cloned into plasmid pACYC184 to produce recombinant plasmid pACIDA, meanwhile the integrase gene was cloned into plasmid pET28a to construct recombinant plasmid pETINT. These two recombinant plasmids were consecutively transformed into E. coli BL(DE3). These transformed bacteria was cultured in the LB medium at 37 ℃ overnight with addition of different concentration of streptomycin. The copy number of total integrons and the copy number of integrated aadA2 at attI site of integrons were determined by using real-time PCR. and the integration frequency is the result of the former divided by the latter. @*Results@#The resulting frequencies were (1.97±0.24)×10-3, (3.23±1.77)×10-3, (3.27±0.67)×10-3, 0.45±0.13 and 1.32±0.11, with respective streptomycin concentrations of 0, 20, 30, 40 and 50 μg/ml. The background frequency of integration without integrase overexpression was less than (1.75±0.33)×10-7. @*Conclusion@#These findings indicate that antibiotic concentration significantly increase recombination frequency of aadA2 resistance cassette at attI site of the integron, catalyzed by integron integrase.(Chin J Lab Med, 2018, 41: 531-535)

Mutations in Streptomycin Resistance Genes and Their Relationship to Streptomycin Resistance and Lineage of Mycobacterium tuberculosis Thai Isolates / 결핵및호흡기질환

BACKGROUND: Streptomycin (SM) is recommended by the World Health Organization (WHO) as a part of standard regimens for retreating multidrug-resistant tuberculosis (MDR-TB) cases. The incidence of MDR-TB in retreatment cases was 19% in Thailand. To date, information on SM resistance (SMR) gene mutations correlated to the SMR of Mycobacterium tuberculosis Thai isolates is limited. In this study, the mutations in rpsL, rrs, gidB, and whiB7 were investigated and their association to SMR and the lineage of M. tuberculosis were explored. METHODS: The lineages of 287 M. tuberculosis collected from 2007 to 2011 were identified by spoligotyping. Drug susceptibility profiles were evaluated by the absolute concentration method. Mutations in SMR genes of 46 SM-resistant and 55 SM-susceptible isolates were examined by DNA sequencing. RESULTS: Three rpsL (Lys43Arg, Lys88Arg, and Lys88Thr) and two gidB (Trp45Ter and Gly69Asp) mutations were present exclusively in the SM resistant M. tuberculosis. Lys43Arg rpsL was the most predominant SMR mutations (69.6%) and prevailed among Beijing isolates (pC, 615A>G, and 330G>T, as lineage signatures for Beijing and EAI were underscored. This study identified 423G>A gidB as a novel sub-lineage marker for EAI6-BGD1. CONCLUSION: Our study suggested that the majority of SMR in M. tuberculosis Thai isolates were responsible by rpsL and gidB polymorphisms constantly providing the novel lineage specific makers.

Scoring Of Central Neurotoxicities of Aminoglycoside Antibiotics – An Experimental Study in Albino Rats.

Background: Aminoglycoside antibiotics are still the drug of choice in variable conditions like resistant tuberculosis and septicaemia. Toxic effects are the greatest hurdle in their liberal use. Their central neuro-toxicities specially in terms of affinity are yet to be explored. Methods: Experimental rats received streptomycin, kanamycin and gentamycin in a dose of 30mg/kg, 400mg/kg and 135 mg/kg respectively, IMI, daily for 21 days. Total lipids, phospholipids, cholesterol and gangliosides were estimated in auditory cortex, medial geniculate body, inferior colliculus, cerebellum and spinal cord in both control and experimental rats. Results: On the basis of statistically significant alterations in aforementioned biochemical parameters, affinity of drugs was quantified by scoring. Streptomycin and kanamycin showed maximum toxicity in terms of scoring of 4 with preferential targets i.e. medial geniculate body and inferior colliculus respectively. Gentamycin showed affinity for higher centres only with equal scoring of 3 for toxicity at three locations i.e. auditory cortex, medial geniculate body and inferior colliculus. Conclusion: Such preferential toxicities might reflect some aspects of mechanism of toxicity of different drugs.

Analysis of antibiotic residues in milk from healthy dairy cows treated with bovine mastitis ointment using ultra-performance liquid chromatography coupled with electrospray tandem mass spectrometry

This study was conducted to analyze penicillin G (PEG), streptomycin (STR) and neomycin (NEO) residues in milk of healthy lactating cows. Milk samples were collected from all four quarters of 12 dairy cows 2–7 days after intramammary infusions of an ointment containing PEG, STR and NEO once (n = 4; group I) or twice (n = 4, group II) daily. Ultra-performance liquid chromatography coupled with electrospray tandem mass spectrometry was used to determine the antibiotic residues in the samples. The correlation coefficient (r 2) of the calibration curves for all antibiotics was > 0.999 and the limits of detection and quantification were 0.002–0.005 µg/mL and 0.007–0.02 µg/mL, respectively. Recovery rates were ranged from 75.5 to 92.3%. In group I, PEG, STR and NEO residues were detected in milk at 2, 3 and 2 days post-treatment, respectively, which were below the maximum residue limit (MRL). In group II, PEG, STR and NEO residues were detected in milk at 2, 3 and 3 days post-treatment, respectively, which were bellow the MRL. These results suggest that a 3-day for milk withdrawal period after the ointment treatment might be sufficient for reduction of the antibiotic residues below the MRL.

Assessment of hearing loss in multi-drug resistant tuberculosis (MDR-TB) patients undergoing Aminoglycoside treatment.

Background: Incomplete treatments and treatment failures has led to Multi-drug resistant tuberculosis, which has emerged as a significant problem in treating tuberculosis and thus the second line drugs are used with the concomitant increase in the incidence of adverse effects. Methods: This prospective study was carried out from June 2009 to May 2014 in the department of ENT in collaboration with TB & Chest at Teerthanker Mahaveer Medical College & Research Centre. Out of 104, only 84 patients were included in our study. Patients were divided into three groups: group I (n=27) patients using Amikacin, group II (n=40) patients using kanamycin and group III (n=17) patients using streptomycin. Baseline pre-treatment pure tone audiometry was performed on all the patients and repeated every three months until completion of therapy. Results: Patients included were 15 to 55 years age with higher number of males (65%, n=55) than females (35%, n =29). Only 22.7% (n=19) of patients were found to be suffered from Hearing Loss. At the end of the study (at 12 month), Overall incidence of HFL was 58.0% (n=11) while incidence of Dead ear was 31.5% (n=6) and LFL was 10.5% (n=2). Amikacin was found to be more Ototoxic than Kanamycin and streptomycin. Conclusion: Aminoglycosides in MDR-TB patients may cause irreversible hearing loss involving higher frequencies and can become a hearing handicap as speech frequencies are too implied in more or less of the patients, thus underlining the need for regular audiologic evaluation in patients of MDR-TB during the treatment.

Volatile compounds of Lamiaceae exhibit a synergistic antibacterial activity with streptomycin

Bacterial infections cause thousands of deaths in the world every year. In most cases, infections are more serious because the patient is already weakened, and often, the bacteria are already resistant to the antibiotics used. Counterparting this negative scenario, the interest in medicinal plants as an alternative to the synthetic antimicrobial drugs is blossoming worldwide. In the present work, we identified the volatile compounds of ethanol extracts of Melissa officinalis, Mentha sp., Ocimum basilicum, Plectranthus barbatus, and Rosmarinus officinalis by gas chromatography/mass spectrometry (GC/MS). Also was evaluated antimicrobial activity of ethanol extracts against 6 bacteria of clinical interest, and was tested the interaction of these extracts with a commercial antibiotic streptomycin. Phytol was a compound identified in all extracts by GC/MS, being majoritary component in Plectranthus barbatus and Rosmarinus officinalis. The Gram-positive bacteria were more sensitive to ethanol extracts, and Plectranthus barbatus and Rosmarinus officinalis were the most active extracts. Ethanol extracts exhibited a synergetic effect with streptomycin. These results encourage additional studies, in order to evaluate the possibilities of using ethanol extracts of Lamiaceae family as natural source for antibacterial activity.

Impairing methylations at ribosome RNA, a point mutation-dependent strategy for aminoglycoside resistance: The rsmG case / Mutaciones en genes modificadores de ARN ribosómico y la resistencia a aminoglucósidos: el caso del gen rsmG

Introduction: Aminoglycosides like streptomycin are well-known for binding at specific regions of ribosome RNA and then acting as translation inhibitors. Nowadays, several pathogens have been detected to acquire an undefined strategy involving mutation at non structural ribosome genes like those acting as RNA methylases. rsmG is one of those genes which encodes an AdoMet-dependent methyltransferase responsible for the synthesis of m 7 G527 in the 530 loop of bacterial 16S rRNA. This loop is universally conserved, plays a key role in ribosomal accuracy, and is a target for streptomycin binding. Loss of the m 7 G527 modification confers low-level streptomycin resistance and may affect ribosomal functioning. Objectives: After taking into account genetic information indicating that some clinical isolates of human pathogens show streptomycin resistance associated with mutations at rsmG , we decided to explore new hot spots for mutation capable of impairing the RsmG in vivo function and of promoting low-level streptomycin resistance. Materials and methods: To gain insights into the molecular and genetic mechanism of acquiring this aminoglycoside resistance phenotype and the emergence of high-level streptomycin resistance in rsmG mutants, we mutated Escherichia coli rsmG and also performed a genotyping study on rpsL from several isolates showing the ability to grow at higher streptomycin concentrations than parental strains. Results: We found that the mutations at rpsL were preferentially present in these mutants, and we observed a clear synergy between rsmG and rpsL genes to induce streptomycin resistance. Conclusion: We contribute to understand a common mechanism that is probably transferable to other ribosome RNA methylase genes responsible for modifications at central sites for ribosome function.

Introducción. Los aminoglucósidos son moléculas antibióticas capaces de inhibir la síntesis de proteínas bacterianas tras su unión al ribosoma procariota. La resistencia a aminoglucósidos está clásicamente asociada a mutaciones en genes estructurales del ribosoma bacteriano; sin embargo, varios estudios recientes han demostrado, de forma recurrente, la presencia de un nuevo mecanismo dependiente de mutación que no involucra genes estructurales. El gen rsmG es uno de ellos y se caracteriza por codificar una metiltransferasa que sintetiza el nucleósido m 7 G527 localizado en el loop 530 del ribosoma bacteriano, este último caracterizado como sitio preferencial al cual se une la estreptomicina. Objetivo. Partiendo de las recientes asociaciones clínicas entre las mutaciones en el gen rsmG y la resistencia a estreptomicina, este estudio se propuso la caracterización de nuevos puntos calientes de mutación en este gen que puedan causar resistencia a estreptomicina usando Escherichia coli como modelo de estudio. Materiales y métodos. Se indagó sobre el mecanismo genético y molecular por el cual se adquiere la resistencia a estreptomicina y su transición a la resistencia a altas dosis mediante mutagénesis dirigida del gen rsmG y genotipificación del gen rpsL . Resultados. Se encontró que la mutación N39A en rsmG inactiva la proteína y se reportó un nuevo conjunto de mutaciones en rpsL que confieren resistencia a altas dosis de estreptomicina. Conclusiones. Aunque los mecanismos genéticos subyacentes permanecen sin esclarecer, se concluyó que dichos patrones secuenciales de mutación podrían tener lugar en otros genes modificadores del ARN bacteriano debido a la conservación evolutiva y al papel crítico que juegan tales modificaciones en la síntesis de proteínas.

Effect of certain natural products and organic solvents on quorum sensing in Chromobacterium violaceum

Objective: To investigate the effect of seed extracts of Pongamia pinnata, Pyrus pyrifolia, and Manilkara hexandra, bacterial pigment prodigiosin, and three organic solvents (ethanol, methanol, and dimethylsulfoxide), on quorum sensing (QS) in Chromobacterium violaceum (C. violaceum). Methods: C. violaceum was challenged with plant extracts prepared by microwave assisted extraction method, prodigiosin, and organic solvents. Effect of these test substances on C. violaceum growth, and quorum sensing regulated pigment (violacein) production was studied by broth dilution assay. High performance liquid chromatography was also applied to generate chromatographic fingerprint of the active extracts. Effect of sub-minimum inhibitory concentration level of the antibiotic streptomycin on quorum sensing regulated pigment production was also studied. Results: Pongamia pinnata seed extracts and prodigiosin were found to possess anti-QS, and Manilkara hexandra and Pyrus pyrifolia seed extracts to possess QS-enhancing effect in C. violaceum. Dimethylsulfoxide was found to enhance violacein production, whereas ethanol and methanol reduced violacein production in C. violaceum. Streptomycin at sub-minimum inhibitory concentration level was able to significantly arrest QS-regulated pigment production in C. violaceum and Serratia marcescens. Conclusions: Prodigiosin and the seed extracts used in this study could affect quorum sensing in C. violaceum to a notable extent. Results of this study also emphasize the importance of inclusion of appropriate solvent controls (negative controls) in bioassays designed for screening of antimicrobial and/or anti-QS compounds. Antipathogenic potential of low concentrations of streptomycin was also demonstrated.

Production of polypeptide antibiotic from Streptomyces parvulus and its antibacterial activity

A highly potent secondary metabolite producing actinomycetes strain is isolated from marine soil sediments of Visakhapatnam sea coast, Bay of Bengal. Over all ten strains are isolated from the collected soil sediments. Among the ten actinomycetes strains the broad spectrum strain RSPSN2 was selected for molecular characterization, antibiotic production and its purification. The nucleotide sequence of the 1 rRNA gene (1261 base pairs) of the most potent strain evidenced a 96% similarity with Streptomyces parvulus 1044 strain, Streptomyces parvulus NBRC 13193 and Streptomyces parvulus BY-F. From the taxonomic features, the actinomycetes isolate RSPSN2 matches with Streptomyces parvulus in the morphological, physiological and biochemical characters. Thus, it was given the suggested name Streptomyces parvulus RSPSN2. The active metabolite was extracted using ethyl acetate (1:3, v/v) at pH 7.0. The separation of active ingredient and its purification was performed by using both thin layer chromatography (TLC) and column chromatography (CC) techniques. Spectrometric studies such as UV-visible, FTIR, and NMR and mass were performed. The antibacterial activity of pure compound was performed by cup plate method against some pathogenic bacteria including of streptomycin resistant bacteria like (Pseudomonas mirabilis. Pseudomonas putida and Bacillus cereus). In conclusion, the collected data emphasized the fact that a polypeptide antibiotic (Actinomycin D) was produced by Streptomyces parvulus RSPSN2.

Effect of certain natural products and organic solvents on quorum sensing in Chromobacterium violaceum

OBJECTIVE@#To investigate the effect of seed extracts of Pongamia pinnata, Pyrus pyrifolia, and Manilkara hexandra, bacterial pigment prodigiosin, and three organic solvents (ethanol, methanol, and dimethylsulfoxide), on quorum sensing (QS) in Chromobacterium violaceum (C. violaceum).@*METHODS@#C. violaceum was challenged with plant extracts prepared by microwave assisted extraction method, prodigiosin, and organic solvents. Effect of these test substances on C. violaceum growth, and quorum sensing regulated pigment (violacein) production was studied by broth dilution assay. High performance liquid chromatography was also applied to generate chromatographic fingerprint of the active extracts. Effect of sub-minimum inhibitory concentration level of the antibiotic streptomycin on quorum sensing regulated pigment production was also studied.@*RESULTS@#Pongamia pinnata seed extracts and prodigiosin were found to possess anti-QS, and Manilkara hexandra and Pyrus pyrifolia seed extracts to possess QS-enhancing effect in C. violaceum. Dimethylsulfoxide was found to enhance violacein production, whereas ethanol and methanol reduced violacein production in C. violaceum. Streptomycin at sub-minimum inhibitory concentration level was able to significantly arrest QS-regulated pigment production in C. violaceum and Serratia marcescens.@*CONCLUSIONS@#Prodigiosin and the seed extracts used in this study could affect quorum sensing in C. violaceum to a notable extent. Results of this study also emphasize the importance of inclusion of appropriate solvent controls (negative controls) in bioassays designed for screening of antimicrobial and/or anti-QS compounds. Antipathogenic potential of low concentrations of streptomycin was also demonstrated.

Evaluation of screening tests for antimicrobial residues in milk from individual cows treated with a combination of penicillins G and streptomycin / Valoración de pruebas de campo para detección rápida de residuos antimicrobianos en leche individual de vacas tratadas con una combinación de penicilinas y estreptomicina / Valoração de testes de campo para detecção rápida de resíduos antimicrobianos em leite individual de vacas tratadas com uma mistura de penicilinas e estreptomicina

Abstract Background: in Colombia, the law (Resolution 1382, 2013) prohibits the sale of milk that contains any antimicrobial drug residues, although no specific official screening tests and detection limits have been specified. At present, milk with positive results to both the Delvotest® and Snap® assays is simply rejected. To avoid contaminating bulk tanks with milk from individually treated cows, producers would benefit from having on-farm screening tests to conduct their own quality controls. In addition, on-site testing would allow farmers to check if the withdrawal times of commercially-available generic products are in accordance with labeled recommendations. Material and Methods: In this study, two commonly used rapid detection tests (Delvotest® and SNAP® specific for beta-lactams) were used on milk from 39 subclinical mastitic Holstein cows that were prescribed with daily intramuscular injections of a commercial suspension containing 8.000.000 IU of penicilin G (75% procaine penicilin G, 25% potasium penicillin) and 8 g of streptomycin sulfate, for a total of 4 days. Cows were individually milked and samples collected every 12 hours the day before, and for 3 days after the recommended withdrawal time of three days post-treatment. To inactivate the potential action of natural inhibitors of microbial growth that may be present in milk (ie., lysozyme and lactoferrin), the results of the Delvotest® were compared before and after milk samples were subjected to heat treatment (82°C for 5 minutes). Results: When the Delvotest® was used as per manufacturer's instructions (i.e., without heating), 7 of 39 cows were positive for one more day past the recommended withdrawal period. However, the results of the Snap® specific for beta-lactams and Delvotest® post-heating showed that only 2 of those 7 cows were positive, suggesting that 5 animals gave false positive results. For the 312 milk samples analyzed, a high degree of concordance was observed (Kappa coefficient=0.74±0.1) between the Snap® and Delvotest® post-heating. Conclusions: Considering that the streptomycin in this product is known to be eliminated faster than penicillin-G, the results suggest that the efficacy of the Delvotest® (after heat treatment) is similar to that of the Snap® beta-lactams for the detection of penicillin residues. However, when the Delvotest® was not preceded by heat treatment to inactivate potential natural inhibitors, it yielded a high number of false-positive results. The results also showed that in 95% (37/39) of the cows treated with this commercial product, the labeled instructions of a 3 day withdrawal period were adequate for compliance within the law.

Resumen En Colombia, la ley (Resolución 1382, 2013) prohíbe la venta de leche que contenga residuos de cualquier medicamento antimicrobiano, aunque no se especifican pruebas oficiales ni límites de detección que deban cumplir. Actualmente, la leche que emite resultados positivos a los kits del Delvotest® y Snap® simplemente es rechazada. Para evitar contaminar tanques de acopio con leche de vacas tratadas, los productores se beneficiarían de tener pruebas in situ que les permitan hacer sus propios controles. Además, ello permitiría comprobar si los tiempos de descarte de productos comerciales cumplen con las recomendaciones de los insertos. En este estudio se evaluaron dos pruebas de detección rápida (Delvotest® y SNAP® específico parar beta-lactámicos) en leche de 39 vacas con mastitis subclínica que fueron tratadas con inyecciones diarias intramusculares de una suspensión comercial de 8.000.000 UI de penicilina G (75% penicilina procaínica G, 25% penicilina potásica) y 8 g de sulfato de estreptomicina, durante 4 días. Las vacas se ordeñaron manualmente y recolectaron muestras de leche, cada 12 horas, por 1 día antes y 3 después del tiempo de retiro recomendable de 3 días post-tratamiento. Para inactivar la acción de inhibidores naturales del crecimiento bacteriano que pueden estar presentes en leche (ej, lisozima y lactoferrina), los resultados del Delvotest® se compararon antes y después de que las muestras de leche fuesen sometidas a calentamiento (82°C por 5 minutos). Cuando el Delvotest® se usó de acuerdo a las instrucciones de la compañía, es decir, sin calentamiento, 7 de 39 vacas dieron positivas por ≥ 1 días pasado el tiempo de retiro recomendado. Sin embargo, los resultados del Snap® y Delvotest® post-calentamiento mostraron que sólo 2 de las 7 vacas eran positivas, sugiriendo que 5 animales estaban dando falsos positivos. En las 312 muestras de leche analizadas se obtuvo un alto grado de concordancia (coeficiente Kappa = 0.74±0.1) entre el Snap® y el Delvotest® post-calentamiento. En conclusión, los resultados sugieren que la eficacia del Delvotest® (post-calentamiento) es similar a la del Snap® específico para beta-lactámicos en lo que respecta a detección de residuos de penicilina. Sin embargo, cuando el Delvotest® no iba precedido de calentamiento para inactivar inhibidores naturales, se produjeron demasiados falsos positivos. Los resultados también mostraron que en el 95% (37/39) de las vacas tratadas con este producto, la recomendación de descarte por 3 días cumplía con la legislación vigente de no contener residuos.

Resumo Na Colômbia, a lei (Resolução 1382 de 2013) proíbe a venda do leite que tenha resíduos de qualquer medicamento antimicrobiano, embora não se especifiquem testes oficiais nem limites de detecção que devam se cumprir. Atualmente, o leite que emite resultados positivos aos Kits de Delvotest® e Snap® simplesmente é rejeitado. Para evitar contaminar os tanques de armazenamento com leite de vacas tratadas, os produtores beneficiar-se-iam de ter os testes in situ que lhes permita fazer seus próprios controles. Além, isto permitiria comprovar se os tempos de retiro do leite ao utilizar produtos comerciais cumprem com as recomendações da vide bula. Neste estudo avaliaram-se dois testes de detecção rápida (Delvotest® e SNAP® especifico parar beta-lactâmicos) no leite de 39 vacas com mastite subclínica que foram tratadas com injeções diárias intramusculares de uma suspensão comercial de 8.000.000 UI de penicilina G (75% penicilina procaína G, 25% penicilina potássica) e 8g de sulfato de estreptomicina durante quatro dias. Extraiu-se o leite das vacas com ordenha manual e se fez uma amostragem de leite (cada 12 horas) um dia antes e três dias depois do tempo de retiro do leite, que tinha como recomendável, na vide bula, três dias após final do tratamento. Para inativar a ação de inibidores naturais do crescimento bacteriano, que possam estar presentes no leite (ex. lisozima e lactoferrina), os resultados do Delvotest® compararam-se antes e depois de que as amostras de leite fossem sometidas a aquecimento (82°C durante 5 minutos). Quando o Delvotest® usou-se de acordo com as instruções da companhia, quer dizer, sem aquecimento, sete das 39 vacas deram positivas por ≥ 1 dia passado o tempo de retiro recomendado. Embora, os resultados do Snap® e Delvotest® após aquecimento do leite mostraram que só dois das sete vacas eram positivas, sugerindo que cinco animais estavam apresentando falsos positivos. Nas 312 amostras de leite analisadas obteve-se um alto grau de concordância (coeficiente Kappa = 0.74±0.1) entre o Snap® e o Delvotest® após aquecer o leite. Em conclusão, os resultados sugerem que a eficácia do Delvotest® (após o aquecimento do leite) é similar á do Snap ou especifico para beta-lactâmicos no que respeita a detecção de resíduos de penicilina. Embora, quando o Delvotest® não ia precedido do aquecimento do leite para inativar inibidores naturais, produziram-se muitos falsos positivos. Os resultados também demonstraram que o 95% (37/39) das vacas tratadas com este produto, estavam de acordo com a recomendação de descarte por três dias e cumpria com a legislação vigente de não conter resíduos.

The protective effect of nabk honey against pathological effects of penicillin and streptomycin: histological structure and functions of guinea pigs liver.

This study was designed to determine the protective effect of nabk honey as antioxidant against pathological effects of penicillin and streptomycin histological structure and functions of guinea pigs liver . A total of sixty adult male guinea pigs weighting 800-900g were divided into six groups of ten guinea pigs each, and the experiment lasted 30 days. Animals in group I served as control, animals in group 2 were administrated orally with nabk honey 600 mg/kg, animals in group 3 were intraperitoneally (i.p.) injected with penicillin 50000 IU/kg b.w, animals in group 4 in addition penicillin were orally administrated with nabk honey 600 mg/kg, animals in group 5 were (i.p.) injected with streptomycin 50 mg/kg, and animals in group 6 in addition streptomycin were orally administrated with nabk honey 600 mg/kg. The result showed a significant increase in AST, ALT & ALP levels, and a significant decrease in the levels of total protein and albumin, and addition to histopathological changes in penicillin and streptomycin treated guinea pigs when compared to the control guinea pig. The results of honey administration decreased these histopathological changes, the structure of liver and hepatocytes appearance was more or less similar to control group as well its function. The present results indicate that honey may play an important role as cytoprotective and pave the way for further studies on the possible use of honey.

The effects of penicillin-streptomycin on liver aminotransferases, alkaline phosphatase and total serum protein in rabbits (Orcytolagus coniculus).

The effects of penicillin-streptomycin on some liver enzymes and total serum protein were investigated using thirty adult rabbits (Orcytolagus coniculus) weighing 1.8 – 2.5kg. They were divided into six groups (Groups A – F) of five animals each. Groups A – C received high, moderate and low doses of penicillin-streptomycin, respectively; Group D received penicillin at 10mg/kg twice daily, Group E received streptomycin at 50mg/kg once daily while Group F received normal saline throughout the period of drug administration. All treatments were administered intramuscularly and lasted for ten consecutive days. Serum samples were taken before drug administration (0 hour) to establish baseline parameters and then at 24 and 168 hours post administration of the last dose of the drugs, that is, 11th and 17th days post commencement of treatment. Aspartate amino transferase (AST), alanine amino transferase (ALT), alkaline phosphatse (ALP) and total serum protein were determined in all the serum samples using appropriate methods. The results showed significant increase in AST and ALT when compared with baseline parameters (p < 0.05). In contrast, there was significant decrease in total serum protein (p < 0.05). However, no significant difference was observed in ALP activities before and after drug administration. In conclusion, penicillin-streptomycin could interfere with liver functions by induction of acute hepatitis especially when given in high dosages.

A rapid screening program on the resistance to streptomycin and ethambutol in Mycobacterium tuberculosis isolates by PCR melting curve analysis / 中华流行病学杂志

Objective To evaluate the effects of PCR melting curve analysis assay on a rapid screening program regarding the resistance of Mycobacterium tuberculosis (MTB) clinical isolates to streptomycin and ethambutol.Methods A total of 331 clinical isolates of MTB had been collected since 2007-2009 in Shenzhen.Mutations at codon 306,378-380,406 and 497 of embB gene,codon 43,88 of rpsL gene,and 513-517,905-908 region of rrs gene were detected by PCR melting curve analysis.Results were compared with that of conventional drug susceptibility test.Results Compared to drug susceptibility test,sensitivity,specificity and accuracy for streptomycin resistance were 78.6％,90.1％ and 86.7％,respectively while 83.0％,93.3％ and 91.8％,respectively for ethambutol resistance detected by PCR melting curve analysis.PCR melting curve method was in good agreement with drug susceptibility test.Conclusion PCR melting curve analysis on genetic regions associated with resistance to streptomycin and ethambutol seemed to be a rapid,specific and closed-tube method so it could be used for detection oftreptomycin and ethambutol resistance in MTB.