First report of a blaNDM-resistant gene in a Klebsiella aerogenes clinical isolate from Brazil

Abstract INTRODUCTION: Carbapenemase-resistant enterobacteria that produce the bla NDM gene are found worldwide. However, this is the first report of blaNDM in Klebsiella aerogenes in Brazil. METHODS: The identification of bacterial species was performed using anautomated system and confirmed by biochemical tests, 16S rRNA gene sequencing, and detection of resistance genes. RESULTS: The clinical isolate showed minimum inhibitory concentration resistance to meropenem and polymyxin B at 8mg/L and 4mg/L, respectively. Only the blaNDM gene was detected. CONCLUSIONS: The current report of the blaNDM gene in isolated MDR enterobacteria indicates that this gene can spread silently in a hospital setting.

Distribution of adeB and NDM-1 genes in multidrug resistant Acinetobacter baumannii isolated from infected wound of patients admitted in a tertiary care hospital in Bangladesh

Background: The adeB gene in Acinetobacter baumannii regulates the bacterial internal drug effluxpump that plays a significant role in drug resistance. The aim of our study was to determine theoccurrence of adeB gene in multidrug resistant and New Delhi metallo-beta-lactamase-1 (NDM-1) gene in imipenem resistant Acinetobacter baumannii isolated from wound swab samples in atertiary care hospital of Bangladesh. Methods: A total of 345 wound swab samples were testedfor bacterial pathogens. Acinetobacter baumannii was identified by culture and biochemical tests.Antimicrobial susceptibility pattern was determined by the disc diffusion method according toCLSI standards. Extended spectrum beta-lactamases were screened using the double disc synergytechnique. Gene encoding AdeB efflux pump and NDM-1 were detected by Polymerase ChainReaction (PCR). Results: A total 22 (6.37%) Acinetobacter baumannii were identified from 345wound swab samples and 20 (91%) of them were multidrug resistant. High resistance rates to someantibiotics were seen namely, cefotaxime (95%), amoxyclavulanic acid (90%) and ceftriaxone (82%).All the identified Acinetobacter baumannii were sensitive to colistin and 82% to imipenem. Two(9%) ESBL producing Acinetobacter baumannii strains were detected. adeB gene was detectedin 16 (80%) out of 20 multidrug resistant Acinetobacter baumannii. 4 (18%) of 22 Acinetobacterbaumannii were imipenem resistant. NDM-1 gene was detected in 2 (50%) of the imipenem resistantstrains of Acinetobacter baumannii. Conclusion: The results of this study provide insight into the roleof adeB gene as a potential regulator of drug resistance in Acinetobacter baumanni in Bangladesh.NDM-1 gene also contributes in developing such resistance for Acinetobacter baumannii.

In vitro study on the efficacy of zinc oxide and titanium dioxide nanoparticles against metallo beta-lactamase and biofilm producing Pseudomonas aeruginosa.

Pseudomonas aeruginosa contributes to a multitude of infections exhibiting intrinsic resistance to numerous antibiotics. Metallo beta-lactamase and biofilm production is the most worrisome resistant mechanisms observed in P. aeruginosa. Emergence of antimicrobial resistance by pathogenic bacteria is a major health problem in recent years. Zinc oxide and titanium dioxide nanoparticles comprises of well-known inhibitory and bactericidal effects. The present study is designed to determine the efficacy of zinc oxide and titanium dioxide nanoparticles against metallo beta-lactamase and biofilm producing P. aeruginosa. A total of 51 non-repetitive P. aeruginosa isolates were obtained from Bioline laboratory, Coimbatore. Biofilm and metallo beta-lactamase production was tested by combined disc test and tissue culture plate method. Commercially available zinc and titanium dioxide nanoparticles were obtained and tested against two metallo beta-lactamase and biofilm producing isolates. Both the nanoparticles showed appreciable activity at all tested concentrations. Thus, it is concluded that ZnO and TiO2 nanoparticles may serve as a promising antibacterial agents in coming years.

Antibacterial activities of multi drug resistant Myroides odoratimimus bacteria isolated from adult flesh flies (Diptera: Sarcophagidae) are independent of metallo beta-lactamase gene / Atividades antibacterianas de Myroides odoratimimus isolada de moscas varejeiras adultas (Diptera: Sarcophagidae) são independentes do gene metalo beta lactamase

Flesh flies (Diptera: Sarcophagidae) are well known cause of myiasis and their gut bacteria have never been studied for antimicrobial activity against bacteria. Antimicrobial studies of Myroides spp. are restricted to nosocomial strains. A Gram-negative bacterium, Myroides sp., was isolated from the gut of adult flesh flies (Sarcophaga sp.) and submitted to evaluation of nutritional parameters using Biolog GN, 16S rRNA gene sequencing, susceptibility to various antimicrobials by disc diffusion method and detection of metallo â-lactamase genes (TUS/MUS). The antagonistic effects were tested on Gram-negative and Gram-positive bacteria isolated from human clinical specimens, environmental samples and insect mid gut. Bacterial species included were Aeromonas hydrophila, A. culicicola, Morganella morganii subsp. sibonii, Ochrobactrum anthropi, Weissella confusa, Escherichia coli, Ochrobactrum sp., Serratia sp., Kestersia sp., Ignatzschineria sp., Bacillus sp. The Myroides sp. strain was resistant to penicillin-G, erythromycin, streptomycin, amikacin, kanamycin, gentamycin, ampicillin, trimethoprim and tobramycin. These strain showed antibacterial action against all bacterial strains except W. confusa, Ignatzschineria sp., A. hydrophila and M. morganii subsp. sibonii. The multidrug resistance of the strain was similar to the resistance of clinical isolates, inhibiting growth of bacteria from clinical, environmental and insect gut samples. The metallo â-lactamase (TUS/MUS) genes were absent, and resistance due to these genes was ruled out, indicating involvement of other secretion machinery.

Moscas varejeiras (Diptera: Sarcophagidae) são causa conhecida de miíase e as bactérias de seus intestinos nunca foram estudadas quanto à atividade antibacteriana. Estudos antimicrobianos de Myroides spp restringem-se à cepas hospitalares. Uma bactéria Gram negativa, Myroides sp, foi isolada do intestino de moscas varejeiras adultas (Sarcophaga sp) e submetida à avaliação de parâmetros nutricionais pelo sistema BIOLOG GN, ao sequenciamento genético 16S rRNA, à sensibilidade a vários antimicrobianos pelo método de difusão de discos e à detecção dos genes de metalo beta lactamases (TUS/MUS). Os efeitos antagonistas foram testados contra bactérias Gram negativas e Gram positivas isoladas de material clínico humano, amostras ambientais e intestino do inseto. As espécies bacterianas incluíram Aeromonas hydrophila, A. culicicola, Morganella morganii subsp sibonii, Ochrobactrum anthropi, Weissella confusa, Escherichia coli, Ochrobactrum sp, Serratia sp, Kestersia sp, Ignatzschineria sp e Bacillus sp. A cepa Myroides sp foi resistente à penicilina G, eritromicina, estreptomicina, amicacina, canamicina, gentamicina, ampicilina, trimetoprim e tobramicina. Esta cepa apresentou atividade antimicrobiana contra todas as cepas exceto W.confusa, Ignatzschineria sp, A. hydrophila e M. morgani subsp sibonii. A resistência múltipla da cepa foi semelhante à de isolados clínicos, inibindo bactérias das amostras clínicas, ambientais e do intestino do inseto. Os genes de metalo beta lactamases (TUS/MUS) estavam ausentes, excluindo-se a resistência mediada por esses genes, o que indica o envolvimento de um mecanismo alternativo de secreção.