Spectrum of non-fermenting gram negative bacilli isolated from patients with blood stream infections in a tertiary care hospital in North India

Background: Non-fermenting Gram-negative bacilli (NFGNB) are emerging as important causes of blood stream infections (BSI) and they are a major cause of morbidity and mortality worldwide. High intrinsic resistance of NFGNB to antimicrobial compounds makes the treatment of BSIs caused by them difficult and expensive. The aim of this study was to assess frequency and antibiotic susceptibility pattern of non-fermenting gram-negative rods isolated from blood culture of patients.Methods: A total of 3016 blood samples were received in the Department of Microbiology during the study period. All samples were processed according to standard microbiological procedures. Blood culture was done by automated blood culture system, (BacT/Alert) and identification and antibiotic susceptibility of non-fermenting gram negative bacilli was done by VITEK2 Compact System.Results: A total of 120 NFGNB were identified out of which the most common non-fermenters isolated were Acinetobacter sp. (95) followed by Pseudomonas aeruginosa (11), Burkholderia cepacia (09) Sternotrophomonas maltophilia (03) and Sphingomonas sp. (02). Most of the non -fermenters were multi drug resistant showing a high level of antibiotic resistance to most of the first- and second-line drugs. The most effective drugs were colistin and tigecycline.Conclusions: This study underlines the need to identify NFGNB in tertiary care hospitals and to monitor their susceptibility pattern to guide the clinician for better care and management of patients. Improved antibiotic stewardship and strict infection control measures especially hand washing need to be implemented to prevent emergence and spread of multidrug resistant NFGNB in health care settings.

The frequency and antimicrobial resistance patterns of nosocomial pathogens recovered from cancer patients and hospital environments

Objective: To determine the prevalence and antimicrobial resistance rates of nosocomial pathogens isolated from cancer patients and hospital environments. Methods: A descriptive cross-sectional study was conducted between December 2010 to May 2013 at Radiation and Isotopes Centre of Khartoum, Sudan. A total of 1 503 samples (505 clinical and 998 environmental) were examined. Isolates were identified, and their antimicrobial susceptibility was determined using standard laboratory procedures. Results: Out of 505 clinical samples, nosocomial pathogens were found as 48.1%. Among hospital environment samples, bacterial contaminants were detected in 29.7%of samples. The main microorganisms recovered from cancer patients were Proteus spp. (23.5%), Escherichia coli (22.2%), Pseudomonas aeruginosa (P. aeruginosa) (21.0%) and Staphylococcus aureus (20.2%). The most frequent isolates from hospital environ-ments were Bacillus spp. (50.0%), Staphylococcus aureus (14.2%) and P. aeruginosa (11.5%). The proportions of resistance among Gram-negative pathogens from cancer patients were high for ampicillin, cefotaxime, ceftazidime and ceftriaxone. Moderate resistance rates were recorded to ciprofloxacin, such as 51.0%for P. aeruginosa, 21.7%for Klebsiella pneumoniae and 55.5%for Escherichia coli. Except Klebsiella, there were no significant differences (P ? 0.05) of resistance rates between Gram-negative isolates from cancer patients to those from the hospital environments. The proportions of extended-spectrum b-lactamase producing isolates from cancer patients were not differ significantly (P=0.763) from those collected from the hospital environments (49.2%;91/185 vs. 47%;32/68). Conclusions: The prevalence of nosocomial infection among cancer patients was high (48.1%) with the increasing of antimicrobial resistance rates. Hospital environments are potential reservoirs for nosocomial infections, which calls for intervention program to reduce environmental transmission of pathogens.

The frequency and antimicrobial resistance patterns of nosocomial pathogens recovered from cancer patients and hospital environments

Objective: To determine the prevalence and antimicrobial resistance rates of nosocomial pathogens isolated from cancer patients and hospital environments. Methods: A descriptive cross-sectional study was conducted between December 2010 to May 2013 at Radiation and Isotopes Centre of Khartoum, Sudan. A total of 1. 503 samples (505 clinical and 998 environmental) were examined. Isolates were identified, and their antimicrobial susceptibility was determined using standard laboratory procedures. Results: Out of 505 clinical samples, nosocomial pathogens were found as 48.1%. Among hospital environment samples, bacterial contaminants were detected in 29.7% of samples. The main microorganisms recovered from cancer patients were Proteus spp. (23.5%), Escherichia coli (22.2%), Pseudomonas aeruginosa (P. aeruginosa) (21.0%) and Staphylococcus aureus (20.2%). The most frequent isolates from hospital environments were Bacillus spp. (50.0%), Staphylococcus aureus (14.2%) and P. aeruginosa (11.5%). The proportions of resistance among Gram-negative pathogens from cancer patients were high for ampicillin, cefotaxime, ceftazidime and ceftriaxone. Moderate resistance rates were recorded to ciprofloxacin, such as 51.0% for P. aeruginosa, 21.7% for Klebsiella pneumoniae and 55.5% for Escherichia coli. Except Klebsiella, there were no significant differences (P ≥ 0.05) of resistance rates between Gram-negative isolates from cancer patients to those from the hospital environments. The proportions of extended-spectrum β-lactamase producing isolates from cancer patients were not differ significantly (P = 0.763) from those collected from the hospital environments (49.2%; 91/185 vs. 47%; 32/68). Conclusions: The prevalence of nosocomial infection among cancer patients was high (48.1%) with the increasing of antimicrobial resistance rates. Hospital environments are potential reservoirs for nosocomial infections, which calls for intervention program to reduce environmental transmission of pathogens.

Resistencia a aminoglucósidos por los genes aph(3')-VIa y aac(3')-II en Acinetobacter baumannii aislados en Montería, Colombia / Aminoglycoside resistance by aph(3’)-VIa and aac(3´)-II genes in Acinetobacter baumannii isolated in Montería, Colombia

Objetivo: Investigar la resistencia a aminoglucósidos en cepas de A. baumannii por expresión de genes aph(3')-VIa y aac(3')-H, de una clínica privada en Montería. Materiales y Métodos: Entre agosto de 2005 y febrero de 2007 se recolectaron 17 aislamientos de A. baumannii resistentes a aminoglucosidos de una clínica privada de tercer nivel de Montería. Se determinó la susceptibilidad antimicrobiana mediante la concentración mínima inhibitoria. Se amplificaron y secuenciaron los genes aph(3')-VIa/ aph(3')-Ia, aac(3)-l, aac(3)-ll y aac(6)-la. El análisis de las secuencias se realizó con la base de datos GenBank y el motor de búsqueda BLASTX. El ADN de todos los aislamientos fue preparado en bloques de agarosa y digerido con Apal. Resultados: Dieciséis de 17 aislamientos (94,1%) resistentes a amikacina fueron positivos para el gen aph(3')-VIa y todos los aislamientos fueron positivos para aac(3')-II, ningún aislamiento resulto positivo para los genes aac(3')-l, aph(3')-la y aac(6')-l. La PFGE mostró 8 pulsotipos con dos clones en 11 aislamientos, distribuidos en 7 aislamientos pulsotipo l y 4 aislamientos pulsotipo ll. Los otros seis pulsotipos comprendieron aislamientos no relacionados. Conclusión: La resistencia a los aminoglucósidos en A. baumannii esta codificada principalmente por el gen aph(3')-VIa y el gen aac(3')-II. El análisis epidemiológico molecular demostró que la resistencia a amikacina se debe a la diseminación del gen aph(3')-VIa en aislamientos de A. baumannii que en muchos casos como el de este estudio causa brotes.

Objetive: lnvestigate aminoglucoside-resistant A. baumannii strain by expressing aph(3')-Vla y aac(3')-llgenes, in a clinicfrom Monteria. Materials and Methods: Between august 2005 andfebruary 2007 were collected 17 iso-lates of A. baumannii resistant to aminoglycosides at a private clinic providing tertiary care in Monteria. Antimicrobial susceptibility was determined by minimum inhibitory concentration. Were amplified and sequenced the genes aph(3')-VIa, aph(3')-Ia, aac(3)-I, aac(3)-ll y aac(6)-la. The sequence analysis was performed with the GenBank database and BLASTX search engine. DNA of all isolates were prepared in agarose blocks and digested with the restriction enzyme Apal. Results: Sixteen of 17 isolates (94,1%) resistant to amikacin were positive for the gene aph(3')-VIa and all isolates were positive for aac(3')-II, no isolates were positive for the gene aac(3')-I, aph (3')-Ia and aac(6')-I. The PFGE pulsotypes showed 8 with two clones in 11 isolates, distributed in 7 isolates pulsotypes and 4 isolates pulsotypes ll. The other six pulsotypes included isolates unrelated. Conclusion: resistance to aminoglycosides in A. baumannii is primarily coded by the gene aph(3')-VIa gene and the aac(3')-II. Molecular epidemiological analysis showed that resis-tance to amikacin is due to the large spread of the gene aph(3')-VIa in A. baumannii isolates that in many cases as in this study cause outbreaks.

Imipenem-resistant Acinetobacter baumannii carrying the ISAba1-bla OXA-23, 51 and ISAba1-bla ADC-7 genes in Monteria, Colombia

The purpose of this study was to identify the genes coding for resistance to ceftazidime and imipenem and describe the molecular epidemiology of A. baumannii strains isolated from a clinical center in Colombia. Twenty isolates of imipenem-resistant A. baumannii from an equal number of patients with nosocomial infections were obtained. Primers were used to amplify genes bla IMP, bla VIM, bla OXA-23, bla OXA-24, bla OXA-58, bla OXA-51 and bla ADC-7. To detect insertion sequences ISAba1/bla OXA-23, ISAba1/bla OXA-51 and ISAba1/bla ADC-7, mapping by PCR using combinations of reverse primers ISAba1 and reverse primers of bla OXA-23, bla OXA-51 and bla ADC-7 were used. The amplification products were purified and cloned into PCR 2.1-TOPO vector and transformed into chemically competent Escherichia coli TOP10. These amplicons were then sequenced. PFGE was performed on DNA of A. baumannii isolates digested with ApaI. Results. The DNA profiles obtained included 9 clusters with, four 2-7 isolates per profile, and 5 single-isolate profiles. Of the 20 isolates resistant to imipenem, 15 carried bla OXA-23 gene, 4 contained ISAba1 upstream of bla OXA-51 gene, and 6 contained ISAba1 upstream of bla OXA-23 gene. Eighteen of these isolates carried the bla ADC-7 gene, with 9 of the isolates having ISAba1 located upstream of this gene. This is the first report of the ISAba1 /ADC-7 associated with OXAs genes in A. baumannii isolates from Colombia.

Development of conventional and real-time multiplex PCR assays for the detection of nosocomial pathogens

Nosocomial infections are major clinical threats to hospitalised patients and represent an important source of morbidity and mortality. It is necessary to develop rapid detection assays of nosocomial pathogens for better prognosis and initiation of antimicrobial therapy in patients. In this study, we present the development of molecular methods for the detection of six common nosocomial pathogens including Escherichia coli, Staphylococcus aureus, Streptococcus pneumoniae, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter spp. Conventional multiplex PCR and SYBR Green based real time PCR assays were performed using genus and species specific primers. Blind testing with 300 clinical samples was also carried out. The two assays were found to be sensitive and specific. Eubacterial PCR assay exhibited positive results for 46 clinical isolates from which 43 samples were detected by real time PCR assay. The sensitivity of the assay is about 93.7 percent in blind test isolates. The PCR results were reconfirmed using the conventional culture method. This assay has the potential to be a rapid, accurate and highly sensitive molecular diagnostic tool for simultaneous detection of Escherichia coli, Staphylococcus aureus, Streptococcus pneumoniae, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter spp. This assay has the potential to detect nosocomial pathogens within 5 to 6 hours, helping to initiate infection control measures and appropriate treatment in paediatric and elderly (old aged) patients, pre-and post surgery patients and organ transplant patients and thus reduces their hospitalization duration .

The effectiveness of alcohol gel and other hand-cleansing agents against important nosocomial pathogens

We compared the effectiveness of alcohol gel with that of the traditional hand-cleansing agents in removing clinical strains of Acinetobacter baumannii, methicillin-resistant Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, and Candida albicans from artificially contaminated hands. The fingertips of 6 volunteers were contaminated with approximately 10(6) of microbial cells, and then were washed with: plain liquid soap, alcohol gel, 70% ethyl alcohol (by weight), 10% povidone-iodine liquid soap (PVP-I), and 4% chlorhexidine gluconate detergent. The experiments were performed using a Latin square statistical design, with six 6 x 5 randomized blocks, and the results were estimated by ANOVA. The products reduced from 93.83% (plain liquid soap) to 100% (PVP-I) of the microbial population applied to the hands. In 4 of 6 test microorganisms analyzed, 10% PVP-I, alcohol gel, 70% ethyl alcohol, and 4% chlorhexidine had significantly higher removal rates than plain liquid soap (P 0.05). The results confirm the effectiveness of alcohol gel for hand hygiene and suggest that 10% PVP-I, alcohol gel, 70% ethyl alcohol, and 4% chlorhexidine may be more effective than plain liquid soap for removing A. baumannii, E. coli, E. faecalis, and C. albicans strains from heavily contaminated hands.

Nós comparamos a eficácia do álcool gel com a dos tradicionais agentes degermantes preconizados para a lavagem das mãos na remoção de amostras clínicas de Acinetobacter baumannii, Staphylococcus aureus resistente a meticilina, Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa e Candida albicans das mãos artificialmente contaminadas. As pontas dos dedos dos voluntários (n=6) foram contaminadas com aproximadamente 10(6) de células/microrganismo teste. A seguir, as mãos foram lavadas com sabonete líquido não medicamentoso, álcool gel, álcool etílico 70% (concentração por peso) e soluções anti-sépticas detergentes de polivinilpirrolidona-iodo a 10% (PVP-I) e de gluconato de clorhexidina 4%. Os experimentos foram realizados segundo um quadrado latino com seis blocos aleatorizados 6 x 5. Os resultados foram estimados por ANOVA. Os produtos reduziram de 93,83% (sabão líquido) a 100% (PVP-I 10%) a população microbiana aplicada nas mãos. Em 4 dos 6 microrganismos testes analisados, o PVP-I 10%, o álcool gel, o álcool etílico 70% e a clorhexidina 4% mostraram uma taxa de remoção significantemente superior a do sabão líquido (P 0,05). Os resultados confirmam a eficácia do álcool gel na higienização das mãos e sugerem que o PVP-I 10%, o álcool gel, o álcool etílico 70% e a clorhexidina 4% podem ser os agentes mais eficazes do que o sabão líquido não medicamentoso na remoção de Acinetobacter baumannii, Escherichia coli, Enterococcus faecalis e Candida albicans das mãos altamente contaminadas.