Preparation of colloidal gold immunochromatographic test strip for rapid detection of Pseudomonas aeruginosa / 中国生物制品学杂志

@#Objective To develop a colloidal gold immunochromatographic test strip for rapid and accurate detection of Pseudomonas aeruginosa(P.aeruginosa,Pa).Methods After bioinformatics analysis of Pa outer membrane protein OprF,the gene sequence with abundant antigenic determinants and high intraspecific homology was chemically synthesized,and then connected to pET-28a(+)vector to construct the expression vector pET-28a-OprF,which was transformed into E.coli BL21(DE3)and induced by IPTG. The recombinant OprF protein was purified by Ni Sepharose~(TM)6 Fast Flow and used to immunize two female BALB/c mice for 3～4 times by multi-point subcutaneous injection in the back at the first immunization and intraperitoneal injection at subsequent immunizations. The monoclonal antibodies were screened by animal cell fusion technique,and the colloidal gold immunochromatographic test strip for rapid detection of Pa was prepared by using monoclonal antibody and double antibody sandwich immunochromatography technique. The specificity,sensitivity and stability of the test strip were evaluated.Results Two monoclonal antibodies,Pa-1# and Pa-2#,were obtained with the titer of 1∶409 600,and both of them recognized OprF specifically. The prepared colloidal gold immunochromatographic test strip showed a sensitivity of 1. 0×10~6CFU/mL and had no cross reaction with 9 common respiratory pathogens with a good stability.Conclusion The prepared colloidal gold immunochromatographic test strip can detect Pa rapidly within 15 min,with high specificity and good stability.

Study of the pathological antibacterial effects of tea extract and its role in reducing hypertension in pregnant women

Aims@#Due to the world's direction of alternative medicine and herbal medication, tea leaves have been employed to inhibit certain bacteria that cause urinary tract infections (UTIs). This study aimed to evaluate the effect of green, red and black tea as antibacterial against UTIs in pregnant women and changes in blood pressure and iron level in the blood of their women.@*Methodology and results@#Forty-eight isolates were isolated from 50 women suffering from urinary tract infections, Staphylococcus aureus (18) 37.5%, Escherichia coli (15) 31.25%, Pseudomonas aeruginosa (8) 16.6%, Klebsiella sp. (5) 10.4% and Enterobacter sp. (2) 4.16%. The sensitivity of bacteria to the antibiotics Amikacin, Amoxicillin/Clavulanic, Ampicillin/Sulbactam, Cefixime, Ceftriaxone, Ciprofloxacin, Imipenem, Nitrofurantion, Penicillin and Tetracycline were tested, while E. coli and P. aeruginosa (8), Enterobacter sp. were resistance for Ceftriaxone and Amoxicillin /Clavulanic (100%). While Enterobacter sp. is sensitive to Nitrofurantoin and Imipenem (100%). The ability of the isolates to form biofilms was tested using the Congo red agar method and the micro titrations plate method. The results showed that not all isolates have the ability to produce biofilms and red tea is the most powerful antibacterial under study. Drinking green tea for two weeks regularly in pregnant women who suffer from high blood pressure showed an improvement in blood pressure, as it became normal 118/78 and with the normal iron level in the blood at a rate of hemoglobin = 11.8, while drinking red tea did not change blood pressure measurements in pregnant women with high blood pressure.@*Conclusion, significance and impact of study@#The effect of red tea extract was stronger than other teas used in the study as an antibacterial against urinary tract bacteria. Regular consumed of green tea helps regulate blood pressure, especially for pregnant women who are at risk of hypertension during pregnancy.

Phenotypic and molecular characterization of fluoroquinolone resistant Pseudomonas aeruginosa isolates in Palestine / Caracterização fenotípica e molecular de isolados de Pseudomonas aeruginosa resistentes a fluoroquinolonas na Palestina

Fluoroquinolones are important antimicrobial agents for the treatment of Pseudomonas infections. A total of 11 isolates of P. aeruginosa were collected from different clinical samples from different medical centers in the North West Bank-Palestine during 2017. In this study, resistance to fluoroquinolones and secretions of β-lactamases were detected by phenotypic methods, while presence of β-lactamase gene sequences and other virulence factors were detected by PCR technique. PCR product for gyrA, parC and parE genes were sequenced for further analyses. The phylogenetic analyses, population diversity indices and haplotypes determination were conducted using computer programs MEGA version 6, DnaSP 5.1001 and median-joining algorithm in the program Network 5, respectively. Results of this study showed that the MIC for ciprofloxacin and norfloxacin had a range of 32-256 µg/ml. In addition, all isolates carried either exoT or exoT and exoY genes, different β-lactamase genes and 82% of these isolates harbored class 1 integrons. Analyses of the gyrA, parC and parE sequences were found to be polymorphic, had high haplotype diversity (0.945-0.982), low nucleotide diversity (0.01225-0.02001) and number of haplotypes were 9 for each gyrA and parE genes and 10 haplotypes for parC gene. The founder haplotypes being Hap-1 (18%), Hap-2 (27.3%) and Hap-6 (9.1%) for gyrA, parC and parE genes, respectively. Two of ParE haplotypes were detected as indel haplotypes. The Median-joining- (MJ) networks constructed from haplotypes of these genes showed a star-like expansion. The neutrality tests (Tajima’s D test and Fu’s Fs test) for these genes showed negative values. Palestinian fluoroquinolone resistant P. aeruginosa strains showed high MIC level for fluoroquinolones, β-lactamase producers, carried type III secretion exotoxin-encoding genes, most of them [...].

Fluoroquinolonas são agentes antimicrobianos importantes para o tratamento de infecções por Pseudomonas. Um total de 11 bacilos isolados de P. aeruginosa foram coletados de diferentes amostras clínicas provenientes de diferentes centros médicos na Cisjordânia-Palestina durante o ano de 2017. Neste estudo, resistência a fluoroquinolonas e secreções de β-lactamases foram detectadas por métodos fenotípicos, enquanto a presença de sequências do gene β-lactamase e outros fatores de virulência foram detectados pela técnica de PCR (Proteína C-reativa). O produto de PCR para os genes gyrA, parC e parE foram sequenciados para análises posteriores. As análises filogenéticas, os índices de diversidade populacional e a determinação de haplótipos foram realizados utilizando os softwares MEGA versão 6, DnaSP 5.1001 e o algoritmo de junção de mediana do programa Network 5, respectivamente. Os resultados deste estudo mostraram que a MIC para ciprofloxacina e norfloxacina tinha um intervalo de 32-256 µg/ml. Além disso, todos os bacilos isolados carregavam genes exoT ou exoT e exoY, genes de β-lactamase diferentes e 82% desses isolados continham integrons de classe 1. As análises das sequências gyrA, parC e parE foram consideradas polimórficas, com alta diversidade de haplótipos (0,945-0,982), baixa diversidade de nucleotídeos (0,01225-0,02001) e o número de haplótipos foi de 9 para cada gene de gyrA e parE e 10 haplótipos para o gene parC. Os haplótipos fundadores são Hap-1 (18%), Hap-2 (27,3%) e Hap-6 (9,1%) para os genes gyrA, parC e parE, respectivamente. Dois dos haplótipos parE foram detectados como haplótipos InDel. As redes Median-joining (MJ) construídas a partir de haplótipos desses genes mostraram uma expansão semelhante à de uma estrela. Os testes de neutralidade (teste D de Tajima e teste Fs de Fu) para esses genes apresentaram valores negativos. As cepas palestinas de P. aeruginosa resistentes a fluoroquinolonas mostraram alto nível de MIC para [...].

Phenotypic and molecular characterization of fluoroquinolone resistant Pseudomonas aeruginosa isolates in Palestine

Abstract Fluoroquinolones are important antimicrobial agents for the treatment of Pseudomonas infections. A total of 11 isolates of P. aeruginosa were collected from different clinical samples from different medical centers in the North West Bank-Palestine during 2017. In this study, resistance to fluoroquinolones and secretions of -lactamases were detected by phenotypic methods, while presence of -lactamase gene sequences and other virulence factors were detected by PCR technique. PCR product for gyrA, parC and parE genes were sequenced for further analyses. The phylogenetic analyses, population diversity indices and haplotypes determination were conducted using computer programs MEGA version 6, DnaSP 5.1001 and median-joining algorithm in the program Network 5, respectively. Results of this study showed that the MIC for ciprofloxacin and norfloxacin had a range of 32-256 µg/ml. In addition, all isolates carried either exoT or exoT and exoY genes, different -lactamase genes and 82% of these isolates harbored class 1 integrons. Analyses of the gyrA, parC and parE sequences were found to be polymorphic, had high haplotype diversity (0.945-0.982), low nucleotide diversity (0.01225-0.02001) and number of haplotypes were 9 for each gyrA and parE genes and 10 haplotypes for parC gene. The founder haplotypes being Hap-1 (18%), Hap-2 (27.3%) and Hap-6 (9.1%) for gyrA, parC and parE genes, respectively. Two of ParE haplotypes were detected as indel haplotypes. The Median-joining- (MJ) networks constructed from haplotypes of these genes showed a star-like expansion. The neutrality tests (Tajimas D test and Fus Fs test) for these genes showed negative values. Palestinian fluoroquinolone resistant P. aeruginosa strains showed high MIC level for fluoroquinolones, -lactamase producers, carried type III secretion exotoxin-encoding genes, most of them had integrase I gene and had high level of mutations in QRDR regions in gyrA, parC and parE genes. All these factors may play an important role in the invasiveness of these strains and make them difficult to treat. Isolation of these strains from different medical centers, indicate the need for a strict application of infection control measures in Medical centers in the North West Bank-Palestine that aim to reduce expense and damage caused by P. aeruginosa infections. Molecular analyses showed that Palestinian fluoroquinolone resistant P. aeruginosa haplotypes are not genetically differentiated; however, more mutations may exist in these strains.

Resumo Fluoroquinolonas são agentes antimicrobianos importantes para o tratamento de infecções por Pseudomonas. Um total de 11 bacilos isolados de P. aeruginosa foram coletados de diferentes amostras clínicas provenientes de diferentes centros médicos na Cisjordânia-Palestina durante o ano de 2017. Neste estudo, resistência a fluoroquinolonas e secreções de -lactamases foram detectadas por métodos fenotípicos, enquanto a presença de sequências do gene -lactamase e outros fatores de virulência foram detectados pela técnica de PCR (Proteína C-reativa). O produto de PCR para os genes gyrA, parC e parE foram sequenciados para análises posteriores. As análises filogenéticas, os índices de diversidade populacional e a determinação de haplótipos foram realizados utilizando os softwares MEGA versão 6, DnaSP 5.1001 e o algoritmo de junção de mediana do programa Network 5, respectivamente. Os resultados deste estudo mostraram que a MIC para ciprofloxacina e norfloxacina tinha um intervalo de 32-256 µg/ml. Além disso, todos os bacilos isolados carregavam genes exoT ou exoT e exoY, genes de -lactamase diferentes e 82% desses isolados continham integrons de classe 1. As análises das sequências gyrA, parC e parE foram consideradas polimórficas, com alta diversidade de haplótipos (0,945-0,982), baixa diversidade de nucleotídeos (0,01225-0,02001) e o número de haplótipos foi de 9 para cada gene de gyrA e parE e 10 haplótipos para o gene parC. Os haplótipos fundadores são Hap-1 (18%), Hap-2 (27,3%) e Hap-6 (9,1%) para os genes gyrA, parC e parE, respectivamente. Dois dos haplótipos parE foram detectados como haplótipos InDel. As redes Median-joining (MJ) construídas a partir de haplótipos desses genes mostraram uma expansão semelhante à de uma estrela. Os testes de neutralidade (teste D de Tajima e teste Fs de Fu) para esses genes apresentaram valores negativos. As cepas palestinas de P. aeruginosa resistentes a fluoroquinolonas mostraram alto nível de MIC para fluoroquinolonas, produtores de -lactamase, genes codificadores de exotoxina de secreção tipo III, a maioria deles tinha o gene integrase I e tinha alto nível de mutações nas regiões QRDR nos genes gyrA, parC e parE. Todos esses fatores podem desempenhar um papel importante na invasão dessas cepas e torná-las difíceis de tratar. O isolamento dessas cepas em diferentes centros médicos, indica a necessidade de uma aplicação estrita de medidas de controle de infecção em centros médicos da Cisjordânia-Palestina que visam reduzir despesas e danos causados por infecções por P. aeruginosa. As análises moleculares mostraram que os haplótipos de P. aeruginosa resistentes à fluoroquinolona palestina não são geneticamente diferenciados; no entanto, mais mutações podem existir nessas cepas.

Phenotypic and molecular characterization of fluoroquinolone resistant Pseudomonas aeruginosa isolates in Palestine / Caracterização fenotípica e molecular de isolados de Pseudomonas aeruginosa resistentes a fluoroquinolonas na Palestina

Fluoroquinolones are important antimicrobial agents for the treatment of Pseudomonas infections. A total of 11 isolates of P. aeruginosa were collected from different clinical samples from different medical centers in the North West Bank-Palestine during 2017. In this study, resistance to fluoroquinolones and secretions of ß-lactamases were detected by phenotypic methods, while presence of ß-lactamase gene sequences and other virulence factors were detected by PCR technique. PCR product for gyrA, parC and parE genes were sequenced for further analyses. The phylogenetic analyses, population diversity indices and haplotypes determination were conducted using computer programs MEGA version 6, DnaSP 5.1001 and median-joining algorithm in the program Network 5, respectively. Results of this study showed that the MIC for ciprofloxacin and norfloxacin had a range of 32-256 µg/ml. In addition, all isolates carried either exoT or exoT and exoY genes, different ß-lactamase genes and 82% of these isolates harbored class 1 integrons. Analyses of the gyrA, parC and parE sequences were found to be polymorphic, had high haplotype diversity (0.945-0.982), low nucleotide diversity (0.01225-0.02001) and number of haplotypes were 9 for each gyrA and parE genes and 10 haplotypes for parC gene. The founder haplotypes being Hap-1 (18%), Hap-2 (27.3%) and Hap-6 (9.1%) for gyrA, parC and parE genes, respectively. Two of ParE haplotypes were detected as indel haplotypes. The Median-joining- (MJ) networks constructed from haplotypes of these genes showed a star-like expansion. The neutrality tests (Tajima's D test and Fu's Fs test) for these genes showed negative values. Palestinian fluoroquinolone resistant P. aeruginosa strains showed high MIC level for fluoroquinolones, ß-lactamase producers, carried type III secretion exotoxin-encoding genes, most of them had integrase I gene and had high level of mutations in QRDR regions in gyrA, parC and parE genes. All these factors may play an important role in the invasiveness of these strains and make them difficult to treat. Isolation of these strains from different medical centers, indicate the need for a strict application of infection control measures in Medical centers in the North West Bank-Palestine that aim to reduce expense and damage caused by P. aeruginosa infections. Molecular analyses showed that Palestinian fluoroquinolone resistant P. aeruginosa haplotypes are not genetically differentiated; however, more mutations may exist in these strains.

Fluoroquinolonas são agentes antimicrobianos importantes para o tratamento de infecções por Pseudomonas. Um total de 11 bacilos isolados de P. aeruginosa foram coletados de diferentes amostras clínicas provenientes de diferentes centros médicos na Cisjordânia-Palestina durante o ano de 2017. Neste estudo, resistência a fluoroquinolonas e secreções de ß-lactamases foram detectadas por métodos fenotípicos, enquanto a presença de sequências do gene ß-lactamase e outros fatores de virulência foram detectados pela técnica de PCR (Proteína C-reativa). O produto de PCR para os genes gyrA, parC e parE foram sequenciados para análises posteriores. As análises filogenéticas, os índices de diversidade populacional e a determinação de haplótipos foram realizados utilizando os softwares MEGA versão 6, DnaSP 5.1001 e o algoritmo de junção de mediana do programa Network 5, respectivamente. Os resultados deste estudo mostraram que a MIC para ciprofloxacina e norfloxacina tinha um intervalo de 32-256 µg/ml. Além disso, todos os bacilos isolados carregavam genes exoT ou exoT e exoY, genes de ß-lactamase diferentes e 82% desses isolados continham integrons de classe 1. As análises das sequências gyrA, parC e parE foram consideradas polimórficas, com alta diversidade de haplótipos (0,945-0,982), baixa diversidade de nucleotídeos (0,01225-0,02001) e o número de haplótipos foi de 9 para cada gene de gyrA e parE e 10 haplótipos para o gene parC. Os haplótipos fundadores são Hap-1 (18%), Hap-2 (27,3%) e Hap-6 (9,1%) para os genes gyrA, parC e parE, respectivamente. Dois dos haplótipos parE foram detectados como haplótipos InDel. As redes Median-joining (MJ) construídas a partir de haplótipos desses genes mostraram uma expansão semelhante à de uma estrela. Os testes de neutralidade (teste D de Tajima e teste Fs de Fu) para esses genes apresentaram valores negativos. As cepas palestinas de P. aeruginosa resistentes a fluoroquinolonas mostraram alto nível de MIC para fluoroquinolonas, produtores de ß-lactamase, genes codificadores de exotoxina de secreção tipo III, a maioria deles tinha o gene integrase I e tinha alto nível de mutações nas regiões QRDR nos genes gyrA, parC e parE. Todos esses fatores podem desempenhar um papel importante na invasão dessas cepas e torná-las difíceis de tratar. O isolamento dessas cepas em diferentes centros médicos, indica a necessidade de uma aplicação estrita de medidas de controle de infecção em centros médicos da Cisjordânia-Palestina que visam reduzir despesas e danos causados por infecções por P. aeruginosa. As análises moleculares mostraram que os haplótipos de P. aeruginosa resistentes à fluoroquinolona palestina não são geneticamente diferenciados; no entanto, mais mutações podem existir nessas cepas.

Prevalence of Non Fermenting Gram Negative Bacilli with Their in vitro Antibiotic Sensitivity Profile in RIMS, Ranchi

Background: Non fermenting Gram Negative Bacilli arediverse and complex group of bacteria that possess very fewdefined characteristics. They are aerobic, non-fermentingGram negative bacilli which were initially considered ascontaminants but have come up with life threatening infectionsin hospitals as multidrug resistant organisms posing a threatbecause of their inherent and acquired drug resistance nature.Aims: Isolation and identification of NFGNB in clinical samplesand determination of their antibiotic sensitivity profile.Materials and Methods: The study was conducted in theDepartment of Microbiology, RIMS, Ranchi from February2017-July 2017. Various clinical samples reaching theBacteriology section of the Department of Microbiology wereprocessed and NFGNB were isolated and identified usingstandard procedure and their antibiotic susceptibility wasperformed.Results: A total of 3581 samples were received out of which2246 were culture positive and 217 were identified as NFGNB.The isolation rate of NFGNB was 9.6%. Number of malesaffected by NFGNB was 121 and that of females was 96.Analysed by specimen NFGNB were isolated from 91 urine, 74pus, 11 ear swab, 6 sputum, 8 body fluid, 21 blood culture and6 catheter tip samples. Urine was most common specimenaccounting for 42% followed by pus (34%), blood (9%), earswab (5%), body fluid (4%), sputum and catheter tip (3%each).The clinical samples from indoor patients yielded highestpercentage of NFGNB (38%) followed by ICU patients (36%)and outdoor patients (26%). Among the NFGNB isolatedPseudomonaas aeruginosa (51%) was the most commonfollowed by Acinetobacter baumanii (22%), Pseudomonas spp(19%), Acinetobacter spp, Stenotrophomonas maltophila,Burkholderia cepacia (2% each), Ralstonia spp &Sphingobacterium spp (1%). Non fermenters were highlysensitive to Imipenem accounting for 91.5% followed byPiperacillin-tazobactam (71.5%), cefoperazone sulbactam(67.7%) & Amikacin (55.6%) on an average.Conclusion: NFGNB considered being contaminants in thepast have now emerged as important health care associatedinfections. In our setting Imipenem can be used for thepreliminary treatment of infections caused by nonfermenters.As these organisms are important opportunistic andnosocomial pathogens causing infections inimmunocompromised patients, better infection control policiesin our settings and its implementation is a must.

Carbapenemases novas ou emergentes em Pseudomonas aeruginosa / New or emerging carbapenemases in Pseudomonas aeruginosa

Pseudomonas aeruginosa é um importante agente de infecções relacionadas à assistência à saúde em todo o mundo. O tratamento empírico de infecções graves causadas por esta espécie usualmente inclui os carbapenêmicos. Essa terapia, se inadequada, está relacionada a um aumento significativo da mortalidade. Os principais mecanismos de resistência aos carbapenêmicos em bacilos Gram-negativos são a redução da permeabilidade da membrana externa, hiperexpressão de bombas de efluxo e produção de betalactamases, sendo este último, o mais eficiente. O objetivo deste trabalho consistiu na caracterização de carbapenemases novas ou emergentes e seu contexto genético em P. aeruginosa. Foram utilizados 11 isolados de P. aeruginosa capazes de hidrolisar o imipenem em ensaio espectrofotométrico e negativos para genes de carbapenemases conhecidos e uma cepa produtora de KPC-2. Tais isolados foram submetidos à confirmação do perfil de resistência aos carbapenêmicos pelos métodos de disco-difusão e microdiluição em caldo (CIM), bloqueio enzimático com EDTA e Blue-Carba. O perfil plasmidial foi avaliado utilizando-se os métodos de lise alcalina e eletroforese em campos pulsados (PFGE). Os genomas foram sequenciados utilizando-se o sistema MiSeq. O perfil clonal dos isolados foi avaliado por PFGE e Multilocus Sequence Typing (MLST). Dez isolados apresentaram Blue-Carba negativo, compatível com a presença de carbapenemases fracas. Quatro isolados apresentaram plasmídeos, visualizados em gel de agarose após PFGE. Os plasmídeos do isolado D5303023 foram eletroporados em E. coli TOP 10 e selecionados em meio LB contendo 1µg/mL imipenem, contudo não foram obtidos transformantes. A análise por PFGE identificou sete grupos clonais distintos. Quanto à tipagem por MLST, foi detectado um novo tipo ST3187 e os ST277 e ST1560 foram os predominantes. O isolado D9203039 apresentou uma carbapenemase GES-20 associada a uma betalactamase de espectro estendido GES-19, sendo os genes que as codificam localizados no integron In724. Esse isolado pertence ao ST309, clone de potencial alto risco, associado ao fenótipo de resistência a múltiplos antimicrobianos no México. O genoma da cepa positiva para KPC-2 foi digerido com a S1 nuclease e submetido à PFGE, evidenciando um plasmídeo de aproximadamente 453 kb. Após análise do sequenciamento confirmou-se que a cepa pertence ao ST446 e foi observada a presença do gene blaKPC-2 em um contig de 128.487 bp. Este contig apresentou 99,9% de similaridade com o plasmídeo 1 da cepa P. aeruginosa RW109; no entanto, ensaios de conjugação bacteriana falharam em obter colônias de transconjugantes. O gene blaKPC-2 foi encontrado flanqueado à montante por uma estrutura truncada de um transpóson da família Tn3 e à jusante por uma ISKpn6 truncada. As análises das sequências de DNA das demais cepas evidenciaram a presença de sequências gênicas, que traduzidas, apresentavam similaridade para sete metalobetalactamases (MBL), indicando a potencial presença de novos genes de carbapenemases. Foi caracterizada pela primeira vez no Brasil cepa produtora da carbapenemase GES-20 e o novo ST3187. Foram detectados potenciais novos genes de carbapenemases. O gene blaKPC-2 no isolado J5083553 tem provável localização plasmidial

Pseudomonas aeruginosa is a major agent of healthcare-related infections worldwide. Empirical treatment of serious infections caused by this species usually includes carbapenems. This therapy, if inadequate, is related to a significant increase in mortality. The main mechanisms of carbapenem resistance in Gram-negative bacteria are the reduction of outer membrane permeability, overexpression of efflux pumps and beta-lactamase production, the latter being the most efficient. The aim of this work was the characterization of new or emerging carbapenemases and their genetic context in P. aeruginosa. Eleven P. aeruginosa isolates capable of hydrolyzing imipenem in spectrophotometric assay and negative for known carbapenemases genes were used, as well as a KPC-2 producing strain. These isolates were subjected to confirmation of carbapenem resistance profile by disk diffusion, broth microdilution (MIC) and enzyme inhibition by EDTA and Blue-Carba methods. Plasmid profile was evaluated using alkaline lysis and pulsed field electrophoresis (PFGE) methods. Genomes were sequenced using the MiSeq system. The clonal profile of the isolates was evaluated by PFGE and Multilocus Sequence Typing (MLST). Ten isolates presented negative Blue-Carba, compatible with the presence of weak carbapenemases. Four isolates presented plasmids visualized on agarose gel after PFGE. The plasmids of isolate D5303023 were electroporated into E. coli TOP 10 and selected in LB medium containing 1 µg/mL imipenem, however no transformants were obtained. The PFGE analysis identified 7 distinct clonal groups. As for MLST typing, a new type ST3187 was detected and the ST277 and ST1560 were the predominant types. The genome of the KPC-2 positive strain was digested with S1 nuclease and subjected to PFGE, evidencing a plasmid of approximately 453 kb. Isolate D9203039 presented a GES-20 carbapenemase associated with a GES-19 extended spectrum beta-lactamase. The genes encoding them were located in the In724 integron. This isolate belonged to ST309, a potential high risk clone, associated with the multidrug resistant strain in Mexico. After sequencing it was confirmed that the strain belongs to ST446 and it was observed the presence of the blaKPC-2 gene in a contig of 128,487 bp. This contig was 99.9% similar to plasmid 1 of the P. aeruginosa RW103 strain. However, bacterial conjugation assays failed to obtain transconjugant colonies. The blaKPC-2 gene was found flanked upstream by a truncated structure of a Tn3 family transposon and downstream by a truncated ISKpn6. DNA sequence analysis of the other strains showed the presence of gene sequences, which translated, showed similarity to seven metallo-beta-lactamases (MBL), indicating the potential presence of new carbapenemase genes. It was characterized for the first time in Brazil carbapenemase producing strain GES-20 and the new ST3187. Potential new carbapenemase genes were detected. The blaKPC-2 gene in isolate J5083553 has plasmid localization

Process Optimization for Lipolytic Bacterial Fermentation: Value Addition to the By-products of Oil Seeds

Background: Lipase enzyme has wide application in industries, particularly food and detergent, but high production cost has always limited its use. Extensive studies are underway on production of high quality and low cost lipase enzyme in large amounts, for which microbial sources have been found to be the best. Aim: To estimate the potential of oil cakes for bacterial lipase production. Methodology: By-products of different oil seeds viz. neem, sesame, flax, mustard, coconut, castor, and groundnut were used for the preparation of fermentation media to culture lipolytic Pseudomonas aeruginosa. Optimization of growth condition was done with respect to different parameters such as fermentation time, nitrogen supplements, carbon additives, and lipid sources. Results: A good lipolytic P. aeruginosa JCM5962 (T) strain was isolated from soil of sugarcane field. Results of the study showed that coconut, sesame, neem, flax and mustard oilcakes induced good lipolytic activity from bacteria. Negligible lipase activity was obtained when organism was cultured in castor and groundnut oilcake medium. 1% ammonium nitrate as an additional nitrogen supplement was found to be ideal parameter for improved production. Conclusion: According to present work, lipases could be economically produced by P. aeruginosa using low cost oil cakes as potent substrate for fermentation medium.

Screening and characterisation of two Pseudomonas aeruginosa from aquaculture and water environment

Aims@#Pseudomonas has been associated with diseases occurring in people with weakened or compromised immune system after exposure to contaminated water. The diseases are commonly treated with antibiotics. However, the bacteria had developed resistances to commonly used antibiotics making treatment a difficult task. Therefore, the continuous surveillance of susceptibility of Pseudomonas especially for the human pathogen P. aeruginosa to commonly clinical and aquaculture farming used antibiotics is important to ensure that serious infections remain susceptible to those antibiotics.@*Methodology and results@#In this study, the bacteria were screened from water, sediment and fish from rivers and aquaculture farms around Kuching, Sarawak. A total number of 38 presumptive P. aeruginosa were isolated using CHROMagar TM Pseudomonas and subjected to a series of biochemical tests. Out of all the isolates tested, only two isolates designated as AS-R10(S) and BK2-OLT2(S) fulfilled the biochemical characteristics of P. aeruginosa. 16S rRNA gene sequencing further confirmed these two isolates as P. aeruginosa based on their 100% similarity with P. aeruginosa strain GD1 and P. aeruginosa strain PA1201 in NCBI database. These two isolates were tested for their susceptibilities against nine common antibiotics used in both clinical and aquaculture farming nowadays: imipenem, piperacillin, meropenem, amikacin, gentamicin, ciprofloxacin, ceftazidime, tobramycin and norfloxacin according to CLSI standard using disk diffusion method.@*Conclusion, significance and impact of study@#The two isolates exhibited total susceptibility to all the antibiotics analysed, suggesting the effectiveness of the antimicrobial agents towards P. aeruginosa isolated from aquaculture and water environment in the study area.

Effects of biocide exposure on P. Aeruginosa, E. coli and A. Baumannii complex isolates from hospital and household environments / Efectos de la exposición a biocidas en aislados ambientales de P. Aeruginosa, E. coli y del complejo A. Baumannii hospitalarios y de la comunidad

Background: Bacterial responses to biocide exposure and its effects on survival and persistence remain to be studied in greater detail. Aim: To analyse the viability and survival of environmental isolates from household and hospital settings after biocide exposure. Methods: The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of chlorhexidine (CHxG), benzalkonium chloride (BAC) and triclosan (TC) were determined in isolates of Pseudomonas aeruginosa, Acinetobacter baumannii complex and Escherichia coli collected from hospital and house- holds environments. Viability was monitored after exposure and removal of biocides using agar cultures and flow cytometry. Findings: P. aeruginosa isolates showed greater tolerance for all biocides tested whereas A. baumannii complex and E. coli were less tolerant. When compared with reference strains, biocide tolerance was up to 8 to 13-fold higher for TC and BAC respectively. Flow cytometry showed that biocide exposure may induce viable but non-growing states in P. aeruginosa and E. coli isolates before becoming fully replicative. Changes in the susceptibility profile in one isolate of A. baumannii complex were observed after biocide exposure. Discussion: Bacteria isolates from hospital and households were able to recover after biocide exposure at bactericidal concentrations favouring persistence and spread of biocide-tolerant strains. This study reinforces that cleaning compliance should be monitored by non-culture based tests. Novel formulations in cleaning and disinfection protocols should be revisited in hospitals harbouring P. aeruginosa and A. baumannii multidrug resistant isolates.

Introducción: El efecto de la exposición a biocidas en las poblaciones bacterianas, su viabilidad y persistencia requieren de estudios detallados. Objetivo: analizar la viabilidad y persistencia de bacterias de ambientes hospitalarios y domésticos posterior a la exposición a biocidas. Materiales y Métodos: En un estudio experimental in vitro se determinó la concentración inhibitoria mínima (CIM) y la concentración bactericida (CBM) para chlorhexidina (CHxG), cloruro de benzalconio (BAC) y triclcosan (TC) en aislados de Pseudomonas aeruginosa (10), el complejo Acinetobacter baumannii (5) y Escherichia coli (5) obtenidos de ambientes hospitalarios y domésticos. La viabilidad y susceptibilidad bacteriana después de la exposición y remoción del biocida fue evaluada por citometria de flujo y cultivo. Resultados: Independiente de su procedencia P. aeruginosa presentó mayor tolerancia a todos los biocidas. El complejo A. baumannii y E. coli fueron hasta 8 a 13 veces más tolerantes a BAC y TC que las cepas de referencia. Se observó que la exposición a biocidas altamente efectivos induce formas viables no replicativas en P. aeruginosa y E. coli. Un aislado del complejo A baumannii presentó cambios en el perfil de susceptibilidad posterior a la exposición. Discusión: Aislados tanto de ambiente hospitalario como de la comunidad pueden recuperarse después de la exposición a concentraciones bactericidas de los biocidas favoreciendo la persistencia y diseminación de bacterias no replicativas. Por lo anterior métodos alternativos al cultivo deben utilizarse en el seguimiento de protocolos de limpieza y desinfección. Los tiempos de recuperación de la viabilidad bacteriana deben tenerse en cuenta en la formulación de protocolos para erradicar y/o controlar cepas hospitalarias de P. aeruginosa o A. baumannii multirresistentes.

Ceftolozane-tazobactam activity against drug-resistant Enterobacteriaceae and Pseudomonas aeruginosa causing healthcare-associated infections in Latin America: report from an antimicrobial surveillance program (2013-2015)

ABSTRACT This study evaluated the in vitro activity of ceftolozane-tazobactam and comparator agents tested against Latin American isolates of Enterobacteriaceae and Pseudomonas aeruginosa from patients with health care-associated infections. Ceftolozane-tazobactam is an antipseudomonal cephalosporin combined with a well-established β-lactamase inhibitor.A total of 2415 Gram-negative organisms (537 P. aeruginosa and 1878 Enterobacteriaceae) were consecutively collected in 12 medical centers located in four Latin American countries. The organisms were tested for susceptibility by broth microdilution methods as described by the CLSI M07-A10 document and the results interpreted according to EUCAST and CLSI breakpoint criteria. Results: Ceftolozane-tazobactam (MIC50/90, 0.25/32 µg/mL; 84.2% susceptible) and meropenem (MIC50/90, ≤0.06/0.12 µg/mL; 92.6% susceptible) were the most active compounds tested against Enterobacteriaceae. Among the Enterobacteriaceae isolates tested, 6.6% were carbapenem-resistant Enterobacteriaceae and 26.4% exhibited an extended-spectrum β-lactamase non-carbapenem-resistant phenotype. Whereas ceftolozane-tazobactam showed good activity against extended-spectrum beta-lactamase, non-carbapenem-resistant phenotype strains of Enterobacteriaceae (MIC50/90, 0.5/>32 µg/mL), it lacked useful activity against strains with a (MIC50/90, >32/>32 µg/mL; 1.6% S) carbapenem-resistant phenotype. Ceftolozane-tazobactam was the most potent (MIC50//90, 0.5/16 µg/mL) β-lactam agent tested against P. aeruginosa isolates, inhibiting 86.8% at an MIC of ≤4 µg/mL. P. aeruginosa exhibited high rates of resistance to cefepime (16.0%), ceftazidime (23.6%), meropenem (28.3%), and piperacillin-tazobactam (16.4%). Conclusions: Ceftolozane-tazobactam was the most active β-lactam agent tested against P. aeruginosa and demonstrated higher in vitro activity than available cephalosporins and piperacillin-tazobactam when tested against Enterobacteriaceae.

Clinical observation of piperacillin/tazobactam′s optimized regimen formulated by T>MIC% for 59 patients with P.aeruginosa infection / 药学实践杂志

Objective To observe the treatment efficacy of piperacillin/tazobactam regime for P.aeruginosa infection formulated by the method of the ratio of T above MIC (T>MIC%).Methods 59 hospitalized patients with P.aeruginosa infection were diagnosed by etiological diagnosis which was sensitive to piperacillin/tazobactam from Jan.to April.2015.Before treatment, all patients were randomly divided into the control group and the test group.Patients in the control group were treated with 4.5 g piperacillin/tazobactam once and repeated every six hours.Patients in test group were treated with 4.5 g piperacillin/tazobactam once and repeated every twelve hours.The two groups were injected by 15 mg/kg amikacin once a day based on the above program.The other treatments were kept to be same.Results Between the two groups, the clinical efficiency rate and total hospital stay were equivalent, bacterial clearance rate and incidence of adverse reactions were similar, there were no difference between CRP and APACHE Ⅱ score before and after treatment.Conclusion The regime of piperacillin/tazobactam for P.aeruginosa infection formulated by the method of the ratio of T above MIC (T>MIC%)was safe, effective and feasible.

Mechanisms of carbapenem resistance in endemic Pseudomonas aeruginosa isolates after an SPM-1 metallo-β -lactamase producing strain subsided in an intensive care unit of a teaching hospital in Brazil

Carbapenem-resistance mechanisms are a challenge in the treatment of Pseudomonas aeruginosa infections. We investigated changes in P. aeruginosa carbapenem-resistance determinants over a time period of eight years after the emergence of São Paulo metallo-β-lactamase in a university hospital in Rio de Janeiro, Brazil. Patients admitted to the intensive care unit (ICU) were screened for P. aeruginosa colonisation and followed for the occurrence of infections from April 2007 to April 2008. The ICU environment was also sampled. Isolates were typed using random amplified polymorphic DNA, pulsed-field gel electrophoresis and multilocus sequence typing. Antimicrobial susceptibility was determined by disk diffusion and E-test, production of carbapenemases by a modified-CarbaNP test and presence of carbapenemase-encoding genes by polymerase chain reaction. Non-carbapenemase resistance mechanisms studied included efflux and AmpC overexpression by PAβN and cloxacillin susceptibility enhancement, respectively, as well as oprD mutations. From 472 P. aeruginosa clinical isolates (93 patients) and 17 isolates from the ICU environment, high genotypic diversity and several international clones were observed; one environment isolate belonged to the blaSPM-1 P. aeruginosa epidemic genotype. Among isolates from infections, 10 (29%) were carbapenem resistant: none produced carbapenemases, three exhibited all non-carbapenemase mechanisms studied, six presented a combination of two mechanisms, and one exclusively displayed oprD mutations. Carbapenem-resistant P. aeruginosa displayed a polyclonal profile after the SPM-1 epidemic genotype declined. This phenomenon is connected with blaSPM-1 P. aeruginosa replaced by other carbapenem-resistant pathogens.

Detección fenotípica de carbapenemasas en pseudomonas aeruginosa en pacientes que acudieron al hospital de clínicas San Lorenzo de febrero a julio 2013 / Phenotypic detection of carbapenemases in P. aeruginosa in patients attending the hospital de clinicas in San Lorenzo, from February to July 2013

Pseudomonas aeruginosa es uno de los patógenos oportunistas más importantes, causante de infecciones, con altos índices de morbilidad y mortalidad. Los carbapenemes son antibióticos que poseen un amplio espectro de actividad y son altamente potentes, lo cual hacen que sean imprescindibles en el tratamiento empírico. P. aeruginosa presenta diversos mecanismos de resistencia, entre ellos las carbapenemasas tipo metalo-β-lactamasas (MBLs). Debido a los numerosos reportes de bacterias productoras de MBLs, es importante la aplicación de test simples, prácticos y de bajo costo, como pruebas de rutina, para que se pueda identificar a las bacterias productoras de MBLs de forma rápida. El objetivo de este trabajo es determinar fenotípicamente la presencia de carbapenemasas en aislamientos de P. aeruginosa. Estudio prospectivo, descriptivo de corte transversal realizado en aislamientos de P. aeruginosa de pacientes que acudieron al Hospital de Clínicas - San Lorenzo en el periodo de febrero a julio de 2013. Se estudiaron 232 aislamientos de P. aeruginosa, a aquellos con sospecha de carbapenemasas se les aplicó dos métodos de detección fenotípica, discos de EDTA y discos con ácido dipicolinico - Meropenem (DPA-ME). De estos aislamientos, 30 dieron sinergia con la técnica de EDTA y 18 aislamientos positivos con los discos de DPA. A través de los métodos fenotípicos aplicados se pudo comprobar la presencia de cepas productoras de carbapenemasas tipo MBL en una frecuencia de 7,8%. Los tests de combinación de disco podrían ser útiles en la práctica diaria para proporcionar una detección rápida y fiable de MBL carbapenemasas en los aislados de P. aeruginosa cuando las pruebas moleculares no están disponibles.

P. aeruginosa is one of the most important opportunistic pathogens that cause infections with high morbidity and mortality. Carbapenems are antibiotics with a broad spectrum of activity and highly powerful, which makes them indispensable in the empirical treatment. P. aeruginosa has various mechanisms of resistance, including metallobetalactamase (MBL) type carbapenemases. Due to increasing numbers of MBL producing bacteria, it is important to apply simple tests that are practical and inexpensiveas routine protocol in order to rapidly identify MBL producing bacteria. The objective ofthis study was to determine phenotypically the presence of carbapenemases in P aeruginosa isolates. A descriptive cross- sectional study was performed in isolates of P.aeruginosa from patients attending the Hospital de Clinicas - San Lorenzo from February to July, 2013. Two hundred thirty two isolates of P. aeruginosa were studied. Those isolates suspicious of having Carbapenemases were subjected to two phenotypic detection methods: discs of EDTA and discs of dipicolinic acid – Meropenem (DPA-ME). Of these isolates, 30 were synergistic with the technique of EDTA and 18 positive with DPA discs.The presence of strains producing MBL type carbapenemases was determined throughthese phenotypic methods yielding a frequency of 7.8%. The disc combination tests maybe very useful in the daily practice to provide fast and reliable detection of MBL carbapenemases in P. aeruginosa isolates, where molecular biology tests are not available.

Efecto de un extracto etanólico de propóleos sobre Pseudomonas aeruginosa en estado planctónico y sésil / Effect of ethanol extract of propolis on Pseudomonas aeruginosa in planktonic and sessile

Pseudomonas aeruginosa es un bacilo Gram negativo no fermentador de glucosa comúnmente aislado en infecciones nosocomiales. El incremento de la resistencia a los antibióticos y la participación de este microorganismo en patologías que cursan con formación de biopelículas da como resultado la falla usual de los antimicrobianos, por lo que resulta interesante estudiar el extracto etanólico de propóleos (EEP) como alternativa terapéutica frente a este patógeno oportunista. En este sentido, el objetivo principal del estudio fue evaluar el efecto del EEP sobre Pseudomonas aeruginosa en estado planctónico y sésil. El estudio se enmarcó en una investigación de tipo descriptiva, cuasi-experimental. Se determinó la concentración mínima inhibitoria (CMI) y bactericida (CMB) en estado planctónico por el método de macrodilución en tubos y en estado sésil por microdilución sobre biopelículas formadas en placas de poliestireno. Los resultados mostraron que el EEP, posee actividad bacteriostática parcial pero no total a 4% y actividad bactericida a 8% sobre P. aeruginosa en estado planctónico. Mientras que en estado sésil no hubo efecto bacteriostático ni bactericida. Se concluye que el EEP del Edo. Táchira Venezuela es efectivo frente a P. aeruginosa en estado planctónico pero no tiene actividad antimicrobiana sobre biopelículas formadas por la misma especie.

Pseudomonas aeruginosa is a glucose non-fermenting Gram-negative bacillus that is commonly isolated in nosocomial infections. The usual antimicrobials failure is the result of the increase in antibiotics resistance and this microorganism’s involvement in pathologies with biofilm formation. Therefore, the ethanol extract of propolis becomes an interesting subject of study as a therapeutic alternative against this opportunist pathogen. In this regard, the main objective of this investigation was to evaluate the effect of ethanol extract of propolis (EEP) over Pseudomonas aeruginosa in planktonic and sessile state. This research was categorized as a descriptive quasi-experimental type of investigation. It was determined the minimum inhibitory (MIC) and bactericide (MBC) concentration by the macrodilution tubes method in planktonic state, and the microdilution over biofilms formed on polystyrene plates in sessile state. The results showed that whereas there wasn’t a bacteriostatic or bactericide effect in sessile state, the EEP possesses 4% of non total but partial bacteriostatic activity and 8% of bactericide activity over P. aeruginosa in planktonic state. It concludes that the EEP of the Venezuelan state of Táchira is effective against P. aeruginosa in planktonic state but it won’t have antimicrobial activity over biofilms formed by the same species.

Actividad comparativa in vitro de doripenem y otros carbapenemicos frente a pseudomonas aeruginosa aisladas en el laboratorio de microbiología del hospital Vargas de Caracas / Comparative in vitro activity of dorypenem and other carbapenems in pseudomonas aeruginosa isolates on Vargas Caracas Hospital´s Microbiology

Los ensayos de cuantificación de ARN plasmáticos de VIH-1 son importantes para el control de pacientes infectados, así como el monitoreo de la respuesta a la terapia antirretroviral. Por lo tanto, los ensayos comerciales empleados para este propósito deben presentar buena correlación entre si, para dar lugar al manejo terapéutico apropiado. El objetivo del estudio consistió en correlacionar los resultados obtenidos mediante el ensayo de amplificación de señal (bDNA) y PCR en tiempo real (RT-PCR), ambas casas comerciales aprobadas por la FDA y con diferente diana de detección del VIH-1. La validación se realizó con 180 muestras clínicas de pacientes referidos al INHRR. Los resultados fueron comparados con la subpoblación de linfocitos TCD4+ determinados mediante citometría de flujo. El análisis estadístico se realizó empleando el coeficiente de regresión lineal de Pearson (R2) y el valor de contraste de hipótesis con una significancia del 95 %, usando el programa SPSS Statistics v10.0. Se observó una buena correlación entre los ensayos (R2=0.961, p<0.05), siendo la RTPCR más sensible. Las diferencias cuantitativas de carga viral entre las técnicas ensayadas fue menor de 0.5 log10 copias/ml para el 89% de las muestras, y >1 log10 copias/ml solo en dos pacientes, no indicando necesariamente cambio terapéutico. Adicionalmente, se encontró una correlación inversa entre los linfocitos TCD4+ y carga viral del VIH-1 medida por bDNA (R2= 0.20, p<0.05) y RT-PCR (R2= 0.15, p<0.05). Los ensayos evaluados mostraron que ambas técnicas puedes ser empleadas indistintamente para el control de los pacientes VIH positivo.

The assay for quantification of plasma HIV-1 RNA are important for the control of patients infected, as well as the monitoring of the response to antiretroviral therapy. Therefore, the commercial assays used for this purpose must submit good correlation between to give place to the appropriate therapeutic management. In this study, we correlate the results obtained through the testing of signal amplification (bDNA) and real-time PCR (RT-PCR), two comercial technical approved by the FDA and with different targets of detection HIV-1. The validation was carried out with 180 clinical samples of patients referred to the INHRR. The results were compared with the subpopulation of lymphocytes TCD4+ determined by flow cytometry. The statistical analysis was performed using the program SPSS Statistics v10. It was observed good correlation between the tests studied (R2=0.961, p<0.05), with RT-PCR more sensitive. The quantitative differences in viral load between the techniques tested was less than 0.5 log10 copies/ml for the 89% of the samples, and >1 log10 copies/ml in only two patients. Additionally, it was found an inverse correlation between lymphocytes TCD4+ and viral load of HIV-1, measured by bDNA (R2= 0.20, p<0.05) and RT-PCR (R2= 0.15, p<0.05). Therefore, these assays can be employed for the patient control HIV.

Establishment and optimization of loop-mediated isothermal amplification for rapid detection of pseu-domonas aeruginosa / 实用医学杂志

Objective To establish a Loop-mediated Isothermal Amplification (LAMP) for Pseudomonas aeruginosa rapid detection. Method 152 P. aeruginosa strains isolated from nasal swabs and 30 reference strains were applied. P. aeruginosa ATCC15442 was used to develop LAMP amplification and evaluate sensitivity and specificity. Results Sensitivity of LAMP was 103 times higher than PCR, with DNA amount as 132 fg. When LAMP was applied to 30 reference strains and 152 P. aeruginosa strains , the specification was 100% while iden-tification rate reached 94.7%. Conclusion The establishment LAMP showed a promising prospect in P. aerugi-nosa rapid detection.

Antimicrobial Susceptibility and Clonal Distribution of the Blood Isolates of Pseudomonas aeruginosa from Two Korean Hospitals

An increasing prevalence of infections caused by multidrug-resistant (MDR) Pseudomonas aeruginosa (P. aeruginosa) causes a serious therapeutic problem in clinical setting. This study investigated the antimicrobial susceptibility, resistance mechanisms against aminoglycosides, and molecular epidemiology of 76 blood isolates of P. aeruginosa from two Korean hospitals. Thirty-four isolates were susceptible to all 13 antimicrobial agents tested, whereas 28 isolates showed a MDR or extensively drug-resistant phenotype. There was a significant difference in resistance rates of P. aeruginosa isolates against aztreonam, piperacillin-tazobactam, imipenem, meropenem, ciprofloxacin, and norfloxacin between two hospitals. Genes for aminoglycoside-modifying enzymes (AMEs), including aphA6 (n = 14), aadB (n = 11), aacA4 (n = 8), and aphA1 (n = 1), and 16S rRNA methylase armA (n = 6) were detected in 26 P. aeruginosa isolates resistant to aminoglycosides. There was no significant difference in carriage of genes for AME and 16S rRNA methylase between two hospitals, but aacA4 and aphA1 were specifically detected in P. aeruginosa isolates from one hospital. Seventy-six P. aeruginosa isolates were classified into 55 pulsotypes at similarity value of 0.85, and 31 and 24 pulsotypes were specifically detected in each hospital. This study demonstrates that differences in antimicrobial susceptibility of P. aeruginosa isolates between two hospitals are possibly due to the presence of diverse clones specific in each hospital.

Biophysicochemical characterization of Pyocin SA189 produced by Pseudomonas aeruginosa SA189

Abstract Pseudomonas aeruginosa, in spite of being a ubiquitous organism (as it is found in soil, water, and humans), is also an opportunistic pathogen. In order to maintain its diversity in the community, it produces various toxic proteins, known as, bacteriocins. In the present study, pyocin SA189, which is a bacteriocin produced by P. aeruginosa SA189 (isolated from a clinical sample) was characterized. P. aeruginosa SA189, as identified by the conventional and 16S rRNA gene amplification, produced pyocin SA189 of molecular weight of 66 k Da. The pyocin showed antimicrobial activity against several clinically relevant Gram-positive and Gram-negative bacteria and was substantially stable for wide ranges of temperature and pH. Furthermore, the pyocin also retained its biological activity upon treatment with metal ions, organic solvents, and various proteolytic and lipolytic enzymes. The data from the growth kinetics indicated that the maximum bacteriocin production occurred in the late log phase. Overall, our results signify the potential of pyocin SA189 as a bio-control agent.

Sub-MIC of antibiotics induced biofilm formation of Pseudomonas aeruginosa in the presence of chlorhexidine

Public health is facing a new challenge due to the alarming increase in bacterial resistance to most of the conventional antibacterial agents. It has been found that only minor cell damage is caused when exposed to sub-lethal levels of antimicrobial. Biofilms can play an important role in producing resistance, which is developed to reservoirs of pathogens in the hospital and cannot be easily removed. The aim of this study was to test whether the sub-lethal dose of antibiotics can induce biofilm formation of P. aeruginosa following incubating in the presence and absence of chlorhexidine. Standard antibiotic-micro broth 96-flat well plates were used for determination of MIC and biofilm assay. The adherence degree of biofilm was determined by estimation of OD630 nm values using ELISA reader. The mean 22 isolates of P. aeruginosa growing in culture with presence and absence of chlorhexidine, could exhibited the significant (p < 0.001) proportion of adherence followed incubation in sub minimal inhibitory concentrations (Sub-MIC) of cefotaxim, amoxicillin, and azithromycin in comparison with control (antibiotic-free broth), while the sub-MIC of ciprofloxacin revealed significant inhibition of biofilm. Conclusion: Incubating the isolates of P. aeruginosa to sub-MIC of antibiotics exhibited induction of biofilm in the presence of chlorhexidine.