Species Of Gram-negative Bacilli Research Articles

Multidrug-resistant and potentially virulent Gram-negative bacilli recovered from urine of slaughtered cattle in Makurdi, Nigeria

Objective: Many reports of bacteriuria in domestic animals allude that animals may serve as hosts and means of spreading zoonotic pathogenic and multidrug-resistant bacteria via contamination of the environment with their urine. This cross-sectional study determined the bacterial load of urine from slaughtered cattle. It investigated the resistance to antimicrobials and pathogenicity potentials of the Gram-negative bacteria recovered from urine samples. Materials and Methods: Urine samples were obtained from 52 slaughtered cattle at the Wurukum Abattoir, Makurdi, Benue State, within a month. Standard microbiological procedures were used to process the samples for the isolation and identification of bacteria. Disc diffusion technique was used to determine the antibiogram of the isolates. Standard procedures also were deployed to examine the expression of virulence factors. Results: Bacteria were isolated from 20 of the 52 urine samples, with the positive samples yield¬ing total aerobic and coliform counts of 2.8 × 103 − 9.1 ×105 and 2.5 × 102 − 3.3 × 105 CFU/ml, respectively. Species of Gram-negative bacilli identified were Escherichia coli (n = 10), Tatumella ptyseous (n = 4), Acinetobacter baumannii (n = 2), and Klebsiella pneumoniae (n = 1). The isolates were all resistant to at least three antimicrobial classes. All the isolates were resistant to the bac¬tericidal action of the serum, while 2 (11.8%) were hemolytic on blood agar. Conclusion: Adequate veterinary examination of slaughtered cattle before presenting for slaugh¬ter is imperative to reduce the contamination of the meat and environment with the urine of cattle with elevated levels of bacteriuria.

P42 Pattern of antibiotics resistance and phenotypic characterization of MDR bacteria isolates in four hospitals of Littoral Region, Cameroon

BackgroundContaminated hospital surface have been recognized to be the most significant reservoir of MDR bacteria (MDRB). The aim of this study was to describe phenotypical characteristics of MDRB species surface contaminants in four hospitals of Littoral region, Cameroon.MethodsWe conducted a descriptive hospital-based cross-sectional study from December 2018 to May 2019. A simple random sampling was used to swab 10 selected equipment items and 10 materials in the mornings after disinfection but before the start of work in seven units (Medical, Paediatric, Operating Theatre, Laboratory, Surgical, Emergency and Maternity). After inoculation in four agar media consecutively (eosin methylene blue, CLED, mannitol salt agar and blood agar) and incubation in appropriate conditions, the Kirby–Bauer disc-diffusion method was used for antimicrobial susceptibility testing. Phenotypic methods using specific indicator discs were used for screening and confirmation of MDRB, of which: ESBL-producing, MRSA, vancomycin-resistant Staphylococcus aureus (VRSA), vancomycin-resistant Enterococcus faecalis (VRE),vancomycin-resistant CoNS (VRCoNS), MDR and XDR. Control strains, Escherichia coli ATCC 25922 (non ESBL-producer) and Klebsiella pneumoniae 700603 (ESBL-producer) and S. aureus ATCC 25923 (MSSA) were used to ensure ability to support growth of the target organism(s), ability to produce appropriate biochemical reactions and adequate inhibition zone diameters.ResultsAmong 50.4% (119/236) showed positive bacteria growth, a total of 89 (13 species), predominant bacteria and those more likely to cause nosocomial infections were selected and tested each one with 18 antibiotics. There was high level of resistance to penicillin [amoxicillin (77.5%) and oxacillin (76.4%)], followed by 3G cephalosporin [ceftazidime (74.2%)] and monobactam [aztreonam (70.8%)]. Although the least level of resistance was observed in carbapenem [imipenem (5.6%)]. The overall prevalence of MDRB was 62.9% (56/89). MRSA were the most detected 57.5% (30/89), followed by ESBL 10.1% (9/89). The lowest percentage was recorded by VRE and XDR both with 1.1% (1/89). According to the type of MDRB in selected isolated bacteria, all the strains (100%) of two species, Aeromonas hydrophila and Enterococcus faecalis, were characterized MDRB. However, S. aureus strains reported significant rate of MDRB, 84.4% (38/45), and recorded 4.4% (2/45) strains of ESBL. Moreover, non-fermenting Gram-negative bacilli, Pasteurella pneumotropica provided 75% (3/4), as well as being the only Gram-negative bacilli species where one strain was resistant to more than three different class of tested antibiotics including carbapenems (imipenem) and was consequently named XDR with 25% (1/4). Military hospital of Douala and Emergency unit were the dominantly MDRB contaminated areas: 39.3% (22/56) and 17.9% (10/56), respectively.ConclusionsMDRB are a current public health problem and hospital surfaces are a worrying reservoir that can be spread to patients, health professionals and visitors. Our results could serve as a timely regional data of hospital surface epidemiological surveillance basis on which preventive strategy of HAIs and AMR should be built.

Extended-Spectrum β-Lactamase and Carbapenemase Producing Gram-Negative Bacilli Infections Among Patients in Intensive Care Units of Felegehiwot Referral Hospital: A Prospective Cross-Sectional Study.

BackgroundOwing to the specific risk profile of its residents, intensive care units (ICUs) are the best place for selection pressure and the epicenter for resistance development and dissemination. Infections with β-lactamase releasing Gram-negative bacilli (GNB) at ICUs are an emerging global threat. This study dogged the magnitude of extended-spectrum β-lactamase (ESBL) and carbapenemase releasing Gram-negative bacilli infections and associated factors among patients in the ICUs of Felegehiwot Referral Hospital, Ethiopia.MethodsA cross-sectional study was done through February to June 2020. Wound swabs, urine, blood and sputum samples were collected from patients in the ICUs symptomatic for infections while excluding those under coma and shock. Bacterial species were verified using standard microbiological methods. Carbapenemase and ESBL production were identified using modified carbapenem inactivation and combined disk diffusion methods, respectively. Multivariable analysis was calculated for factors associated with ESBL production. P-value < 0.05 was taken as cut-off for statistical significance.ResultsOut of 270 patients in the ICU, 67 (24.8%) and 14 (5.2%) had infections with ESBL and carbapenemase releasing GNB, respectively. The most frequent ESBL producing isolates were P. aeruginosa (100%), E. cloacae (100%), K. pneumoniae (82.8%) and E. coli (64%). The predominant carbapenemase producer isolates were K. pneumoniae (27.6%) and E. cloacae (33.3%). Overall, 77 (81.1%) of species were multi-drug resistant. All GNB species were 100% resistant to tetracycline and ampicillin. They are also resistant to cefuroxime, ceftazidime, sulfamethoxazole-trimethoprim and cefotaxime. Prior hospitalization (AOR = 5.5, CI = 2.63–11.46), support with medical care devices (AOR = 23.7, CI = 4.6–12) and arterial intravenous catheterization (AOR = 2.7, CI = 1.3–5.3) had significant association with β-lactamase producing GNB infection.ConclusionInfection with ESBL and carbapenemase producing Gram-negative bacilli linked with an alarming degree of multi-drug resistant isolates is a major healthcare threat among patients in ICUs. Hence, strict adherence to infection prevention practices and wise use of antibiotics are recommended to slow the spread of antimicrobial resistance.

Bacteria with a Potential for Multidrug Resistance in Hospital Material.

The objective of this research was to determine the antimicrobial resistance of bacteria isolated from items related to hygiene and antisepsis, equipment, and instruments used in different hospital wards. Bacterial isolation and identification, phenotypic antimicrobial susceptibility assays, mecA gene detection, and multiple antimicrobial resistance index analysis were performed. In total, 105 bacteria were isolated from 138 items. Of these, 49.52% bacteria were collected from instruments, 43.80% from equipment, and 6.66% from items related to hygiene and antisepsis. All gram-positive bacteria (88 isolates) were identified as coagulase-negative Staphylococcus. Five species of gram-negative bacilli (17 isolates) were isolated, and the prevalence of Enterobacter agglomerans (29.41%), Escherichia coli (11.76%), and Serratia liquefaciens (11.76%) was high. Antimicrobial resistance was reported for 93.33% of the isolates. Gram-positive bacteria were resistant to sulfazotrim (88.64%) and penicillin (82.95%), while gram-negative bacteria showed resistance to sulfazotrim (70.59%) and ampicillin (64.71%). Analysis of multiple antibiotic resistance index showed that 73.33% of the isolates were a high risk to public health. The mecA gene was detected in 23 (71.88%) isolates. The evaluation of microorganisms isolated in the hospital environment revealed their high multidrug resistance index. Thus our study presses the need to pay more attention to the cleanliness of frequently used instruments, which may be potential sources of infections.

Detection of Extended-Spectrum β-Lactamase and Carbapenemase Activity in Gram-Negative Bacilli Using Liquid Chromatography - Tandem Mass Spectrometry.

PurposeSeveral mass spectrometry-based methods for antimicrobial sensitivity testing have been described in recent years. They offer an alternative to commercially available testing systems which were considered to have disadvantages in terms of cost- and time-efficiency. The aim of this study was to develop an LC-MS/MS-based antibiotic hydrolysis assay for evaluating antimicrobial resistance (AMR) of Gram-negative bacteria.Materials and MethodsFour species of Gram-negative bacilli (Klebsiella pneumoniae, Escherichia coli, Providencia stuartii and Acinetobacter baumannii) were tested against six antibiotics from three different classes: ampicillin, meropenem, imipenem, ceftazidime, ceftriaxone and cefepime. Bacterial suspensions from each species were incubated with a mixture of the six antibiotics. Any remaining antibiotic following incubation was measured using LC-MS/MS. The results were interpreted using measurements obtained for an E. coli strain sensitive to all antibiotics and expressed as percentage of hydrolyzed antibiotic. These were subsequently compared to commercially-available system for the bacteria identification and susceptibility testing.ResultsOverall, LC-MS/MS assay and commercial antimicrobial susceptibility platform results showed good agreement in terms of an organism being resistant/sensitive to an antibiotic. The time required to complete the LC-MS/MS-based hydrolysis test was under 5 h, significantly shorter that commercially available susceptibility testing platforms.ConclusionBy using a sensitive strain for results interpretation and simultaneous use of multiple antibiotics, the proposed protocol offers improved robustness and multiplexing over previously described methods for antibiotic sensitivity testing. Nevertheless, further research is needed before routine assimilation of the method, especially for strains with intermediate resistance.

In Vitro Activity of Imipenem/Relebactam Against Gram-Negative Bacilli from Pediatric Patients-Study for Monitoring Antimicrobial Resistance Trends (SMART) global surveillance program 2015-2017.

Studies describing the activity of imipenem/relebactam against gram-negative bacilli (GNB) isolated from pediatric patients are lacking in the peer-reviewed literature. We address this deficiency by reporting on GNB tested against imipenem/relebactam as part of the Study for Monitoring Antimicrobial Resistance Trends global surveillance program. In 2015-2017, 221 laboratories in 59 countries collected 9149 consecutive, aerobic or facultative GNB from pediatric patients (age <18 years) and 100 785 from adult patients with intraabdominal, respiratory, and urinary tract infections. Susceptibility was determined using Clinical and Laboratory Standards Institute (CLSI) broth microdilution methodology and CLSI breakpoints (and US Food and Drug Administration breakpoints for imipenem/relebactam). The 4 most common species of GNB isolated from pediatric patients were Escherichia coli (40.4%), Pseudomonas aeruginosa (17.1%), Klebsiella pneumoniae (13.9%), and Enterobacter cloacae (4.7%); non-Morganellaceae Enterobacterales (NME) accounted for 70.1% of isolates. Imipenem/relebactam inhibited 97.8% of NME from pediatric patients; susceptibility to imipenem was 1.9% lower, and susceptibility to β-lactam comparators (cefepime, ceftazidime, ceftriaxone, piperacillin/tazobactam) was 9.2-25.2% lower. Imipenem/relebactam inhibited 94.2% of P. aeruginosa from pediatric patients; susceptibility to imipenem was 16.2% lower, and susceptibility to β-lactam comparators was 10.2-15.6% lower. Susceptibility was generally slightly higher for isolates from pediatric than adult patients. All K. pneumoniae carbapenemase (KPC)-positive isolates, 93.3% of multidrug-resistant (MDR) NME isolates, and 70.5% of MDR P. aeruginosa isolates from pediatric patients were susceptible to imipenem/relebactam. Imipenem/relebactam provides a new treatment option for infections caused by resistant gram-negative bacilli, including KPC-positive NME, MDR NME, and MDR P. aeruginosa.

An Unusual Case of Pyogenic Liver Abscess Caused by Community-acquired Methicillin-Resistant &lt;i&gt;Staphylococcus aureus&lt;/i&gt;

Hepatic abscesses are the most common type of visceral abscesses. The annual incidence is estimated at 2.3 cases per 100,000 people and is more common in men than women. A considerable proportion of pyogenic liver abscesses are caused by hepatobiliary pathologies. However, it may also result from hematogenous seeding from the systemic circulation. Most pyogenic liver abscesses are polymicrobial in nature consisting of anaerobic and enteric gram-negative bacilli species. Less than 10% of cases are caused by Staphylococcus aureus. Of these, few are caused by Methicillin-resistant Staphylococcus aureus (MRSA) and even fewer from the community-acquired strain. The clinical manifestations of pyogenic liver abscesses usually include fever, abdominal pain and non-specific symptoms like nausea, vomiting, malaise, anorexia and weight loss. Treatment of pyogenic liver abscesses consists of source control with drainage and antibiotic therapy tailored to the isolated causative organism. We present a case of a 51-year-old Caucasian man who presented with severe right upper quadrant abdominal pain of 5 days in duration. Abdominal Computed Tomography (CT) showed a 7.7 by 6.0 centimeter multi-loculated mass in the right hepatic lobe with other scattered foci throughout the liver. The abscess was aspirated with a pigtail drain placed under CT guidance. The aspirated culture grew MRSA sensitive to Doxycycline and Trimethoprim/Sulfamethoxazole.

Distribution of Clinical NDM-1-Producing Gram-Negative Bacteria in Brazil.

New Delhi metallo-β-lactamase (NDM)-producing bacteria have been identified at a worrying rate in Brazil since 2013. Owing to the need to understand the extent of their spread, this study reports the dissemination of blaNDM in different species of Gram-negative bacilli in different regions and states of Brazil. A total of 81 isolates from nine states were studied, including 11 species. All isolates carried blaNDM-1 variant and were considered multidrug resistant. Colistin and amikacin were the agents with higher activity compared with the other drugs tested. The findings indicate that the NDM-1 enzyme is already widespread in the country.

Deep sternal wound infection after cardiac surgery: a comparison of three different wound infection types and an analysis of antibiotic resistance.

Deep sternal wound infection (DSWI) is a severe complication following cardiac surgery. We compared epidemiology, clinical features, and microbiology of three types of DSWI and examined the antibiotic resistance in DSWI patients. From 2011 to 2015, 170 adult post-cardiac surgery DSWI patients were recruited for this study and underwent the pectoralis major muscle flap transposition in our department. Of 170 adult patients with DSWI (mean age of 54 years), the majority (99 patients, 58.2%) had type II DSWI. The three types of DSWI patients showed significant differences in terms of gender, smoking history, chronic obstructive pulmonary disease (COPD), length of intensive care unit (ICU) stay, and hospitalization cost (P<0.05). The most common symptoms of DSWI patients were fever and wound dehiscence accompanied by purulent secretions. Types I and II DSWI were more frequently associated with hypoproteinemia and high leucocyte count (P<0.05). Microbiological diagnosis was available for 77 of 170 patients (45.3%). Of 157 pathogens detected, 87 (55.4%) species of gram negative bacilli were identified and most commonly were Pseudomonas aeruginosa (25.5%) and methicillin-susceptible Staphylococcus aureus (20.4%). However, no statistically significant microbiological differences among the three DSWI types were observed (P>0.05). Notably, P. aeruginosa isolates showed 100% resistance to cefazolin and cefuroxime. Meanwhile, the resistance rate of Acinetobacter baumannii isolates to commonly used antibiotics was greater than 70%, while resistance rates of staphylococcus to penicillin-G were 100% and to clindamycin were over 70%. No isolates were resistant to vancomycin, linezolid, and tigecycline. Three types of DSWI exhibit differences in epidemiology and clinical features. P. aeruginosa and S. aureus are the most common pathogens in DSWI patients and antibiotic resistance is a serious concern in these patients. Therefore, prevention and treatment of DSWI should be closely tailored to clinical features, local microbiological characteristics, and resistance patterns of commonly encountered pathogens.

Composition of pathogenic bacteria of chronic obstructive pulmonary disease patients and drug resistance of gram-negative bacilli for various antibiotics

Objective: In order to analyze the composition and characteristics of pathogens resistance, provide reference for rational use of antibiotics, clinical bacteria isolated from COPD patients in our hospital was investigated. Methods: The 710 patients with chronic obstructive pulmonary disease were collected from August 2010 to February 2014. All patients required to multiple gargle with water or hydrogen peroxide before collecting specimens, ensuring a sterile culture spit sputum specimen box. Susceptibility was determined by the United States Committee for Clinical Laboratory Standards (NCCLS) developed by KB. Results: Gram-negative bacteria as the main species which 813 species were isolated from 710 cases of patients with chronic obstructive pulmonary disease. Pseudomonas aeruginosa based. Gram-positive bacilli was in second place, Staphylococcus aureus, fungi ranks No. 3, Gram-negative bacilli species number and composition were significantly higher than that of Gram-positive bacteria and fungi, and the difference was statistically significant (p<0.05). Pseudomonas aeruginosa and Acinetobacter baumannii resistant to cefazolin higher rate, the difference was statistically significant (p<0.05). Conclusion: Gram-negative bacteria are the main pathogens, and resistance was so strong. So we need to constantly monitor the bacteria resistance, and to guide rationally clinical medicine.

The Risk of Cardiac Device-Related Infection in Bacteremic Patients Is Species Specific: Results of a 12-Year Prospective Cohort.

BackgroundThe species-specific risk of cardiac device-related infection (CDRI) among bacteremic patients is incompletely understood.MethodsWe conducted a prospective cohort study of hospitalized patients from October 2002 to December 2014 with a cardiac device (CD) and either Staphylococcus aureus bacteremia (SAB) or Gram-negative bacteremia (GNB). Cardiac devices were defined as either prosthetic heart valves (PHVs), including valvular support rings, permanent pacemakers (PPMs)/automatic implantable cardioverter defibrillators (AICDs), or left ventricular assist devices (LVADs).ResultsDuring the study period, a total of 284 patients with ≥1 CD developed either SAB (n = 152 patients) or GNB (n = 132 patients). Among the 284 patients, 150 (52.8%) had PPMs/AICDs, 72 (25.4%) had PHVs, 4 (1.4%) had LVADs, and 58 (20.4%) had >1 device present. Overall, 54.6% of patients with SAB and 16.7% of patients with GNB met criteria for definite CDRI (P < .0001). Multivariable logistic regression analysis revealed that 3 bacterial species were associated with an increased risk for CDRI: Staphylococcus aureus (odds ratio [OR] = 5.57; 95% confidence interval [CI], 2.16–14.36), Pseudomonas aeruginosa (OR = 50.28; 95% CI, 4.16–606.93), and Serratia marcescens (OR = 7.75; 95% CI, 1.48–40.48).ConclusionsRisk of CDRI among patients with bacteremia varies by species. Cardiac device-related infection risk is highest in patients with bacteremia due to S aureus, P aeruginosa, or S marcescens. By contrast, it is lower in patients with bacteremia due to other species of Gram-negative bacilli. Patients with a CD who develop bacteremia due to either P aeruginosa or S marcescens should be considered for diagnostic imaging to evaluate for the presence of CDRI.

Nosocomial Infections with IMP-19-Producing Pseudomonas aeruginosa Linked to Contaminated Sinks, France.

We isolated IMP-19–producing Pseudomonas aeruginosa from 7 patients with nosocomial infections linked to contaminated sinks in France. We showed that blaIMP-19 was located on various class 1 integrons among 8 species of gram-negative bacilli detected in sinks: P. aeruginosa, Achromobacter xylosoxidans, A. aegrifaciens, P. putida, Stenotrophomonas maltophilia, P. mendocina, Comamonas testosteroni, and Sphingomonas sp.

Microbiological study of neonatal septicemia with special reference to metallo-beta-lactamase producing pseudomonas aeruginosa

Introduction: Metallo-beta-lactamase (MβL) producing Pseudomonas aeruginosa has emerged as a potential threat in cases of neonatal septicemia and poses great therapeutic challenge for physicians treating such infections. The emergence, selective multiplication & dissemination of antibacterial resistance are a serious global problem. Methods: This study was conducted with the objective to know the microbiological profile of neonatal septicemia cases and to examine the incidence of MβL producing strains among multidrug resistant (MDR) Pseudomonas aeruginosa from the suspected cases of neonatal sepsis between January 2012 – December 2014. A total of 994 cases admitted with the suspicion of neonatal sepsis were investigated. 295 (29.7%) isolates were obtained from the blood cultures of neonates. The isolates were identified and tested for the susceptibility to various antimicrobial agents. Results: Pseudomonas aeruginosa with 116 (48.3%) isolation among 240 Gram negative isolates was the predominant pathogen in our study. All the 74 (63.8%) multidrug resistant P. aeruginosa isolates were screened initially for Imipenem resistance, which were further tested for the presence of MβL by Imipenem-ethylene diamine tetraacetic acid (EDTA) disc method. MβL production was seen in 20 (71.4%) of the 28 Imipenem-resistant Pseudomonas aeruginosa isolates. Conclusion: It creates a great therapeutic problem as it may spread rapidly to various other species of Gram-negative bacilli. Therefore, to prevent the further spread of MβL producers, it is essential to rapidly detect MβL-positive isolates.

Etiology of bacteremia in young infants in six countries.

Background:Neonatal illness is a leading cause of death worldwide; sepsis is one of the main contributors. The etiologies of community-acquired neonatal bacteremia in developing countries have not been well characterized.Methods:Infants <2 months of age brought with illness to selected health facilities in Bangladesh, Bolivia, Ghana, India, Pakistan and South Africa were evaluated, and blood cultures taken if they were considered ill enough to be admitted to hospital. Organisms were isolated using standard culture techniques.Results:Eight thousand eight hundred and eighty-nine infants were recruited, including 3177 0–6 days of age and 5712 7–59 days of age; 10.7% (947/8889) had a blood culture performed. Of those requiring hospital management, 782 (54%) had blood cultures performed. Probable or definite pathogens were identified in 10.6% including 10.4% of newborns 0–6 days of age (44/424) and 10.9% of infants 7–59 days of age (39/358). Staphylococcus aureus was the most commonly isolated species (36/83, 43.4%) followed by various species of Gram-negative bacilli (39/83, 46.9%; Acinetobacter spp., Escherichia coli and Klebsiella spp. were the most common organisms). Resistance to second and third generation cephalosporins was present in more than half of isolates and 44% of the Gram-negative isolates were gentamicin-resistant. Mortality rates were similar in hospitalized infants with positive (5/71, 7.0%) and negative blood cultures (42/557, 7.5%).Conclusions:This large study of young infants aged 0–59 days demonstrated a broad array of Gram-positive and Gram-negative pathogens responsible for community-acquired bacteremia and substantial levels of antimicrobial resistance. The role of S. aureus as a pathogen is unclear and merits further investigation.

English

Many clinically relevant species of Gram-negative bacilli are often resistant to β-lactam antibiotics even to carbapenems. According to CLSI guideline 2013, Carbapenemase producers are screened by zone size <21mm to Meropenem or Etrapenem and phenotypically confirmed by Modified Hodge test. The test of Hodge et al was modified by substituting Escherichia coli for penicillin-susceptible Staphylococcus aureus ATCC 25923, and 10-µg Imipenem disk for a 10-U Penicillin disk. While looking for the Carbapenemase producing strains, some astonishing, unexplainable facts were revealed in this study. Meropenem-resistant test strains were screened (zone diameter in Modified Kirby-Bauer technique<21mm) & for phenotypic confirmation of Carbapenemase production, modified Hodge test was performed. Thereafter the test strains were examined for production of Metallo β Lactamase using Imipenem (10µg) disk and combination of Imipenem and EDTA, followed by test for Bacteriocin production. Two Acinetobacter and one Pseudomonas aeruginosa strains were found to produce a Star like outward distortion. They did not produce Metallo β lactamase. Moreover, screening test for bacteriocin production was also found to be negative. The strains resistant to Carbapenem antibiotics but nonproducers of metallo β lactamase and/or Bacteriocins, have left behind a head twister for us.

KPC-4 Is Encoded within a Truncated Tn 4401 in an IncL/M Plasmid, pNE1280, Isolated from Enterobacter cloacae and Serratia marcescens

We describe the transfer of bla(KPC-4) from Enterobacter cloacae to Serratia marcescens in a single patient. DNA sequencing revealed that KPC-4 was encoded on an IncL/M plasmid, pNE1280, closely related to pCTX-M360. Further analysis found that KPC-4 was encoded within a novel Tn4401 element (Tn4401f) containing a truncated tnpA and lacking tnpR, ISKpn7 left, and Tn4401 IRL-1, which are conserved in other Tn4401 transposons. This study highlights the continued evolution of Tn4401 transposons and movement to multiple plasmid backbones that results in acquisition by multiple species of Gram-negative bacilli.

Antimicrobial susceptibility profiles of Gram-negative bacilli isolated from patients with hepatobiliary infections in Taiwan: results from the Study for Monitoring Antimicrobial Resistance Trends (SMART), 2006–2010

We investigated the trends in antimicrobial resistance among species of Gram-negative bacilli isolated from patients with hepatobiliary tract infections in Taiwan during the period 2006-2010 as part of the Study for Monitoring Antimicrobial Resistance Trends (SMART). During the study period, 1032 isolates of Gram-negative bacilli that had been collected from patients with hepatobiliary infections were tested for susceptibility to 12 antimicrobial agents in accordance with the Clinical and Laboratory Standards Institute guidelines. Enterobacteriaceae accounted for the majority (n = 874, 84.7%) of isolates and Escherichia coli was the most common pathogen (n = 323, 31.3%). There were significantly more E. coli (P = 0.001) and Proteus mirabilis (P = 0.031) isolates collected from patients who had been hospitalized for less than 48 h and significantly more Serratia marcescens (P = 0.035) and Pseudomonas aeruginosa (P = 0.008) isolates collected from patients who had been hospitalized for 48 h or longer. The prevalence of extended-spectrum β-lactamase (ESBL)-producing pathogens was low. The decline in susceptibility rates with time was remarkable for ceftazidime (P = 0.036), ciprofloxacin (P = 0.029), and levofloxacin (P = 0.018). The most effective antibiotics, i.e., those that were active against more than 90% of Enterobacteriaceae, were amikacin, cefepime, imipenem, ertapenem, and piperacillin-tazobactam. Susceptibility of P. aeruginosa to anti-pseudomonal agents was greater than 80%. In this study, we found an overall increase in resistance to antimicrobial agents among Gram-negative bacilli isolated from patients with hepatobiliary tract infections in Taiwan. Surveillance of antimicrobial susceptibility and updates of treatment guidelines are recommended to help achieve optimal therapy for patients with hepatobiliary infections.

Antibiotic Resistance Profiles of Enteric Bacteria Isolated from Kucukcekmece Lagoon (Istanbul - Turkey)

The aim of this study is to find out the density of the fecal bacteria and to analyze resistance to antimicrobials of Gram negative bacilli isolated from the Kucukcekmece Lagoon, Istanbul. Samples were taken monthly from June 2006 to June 2008 and a total of 232 Gram negative bacilli were isolated. Chloramphenicol, tetracycline, nalidixic acid, ampicillin, imipenem, ceftazidime, amikacin, streptomycin and amoxicillin + clavulanic acid were used in antimicrobial susceptibility tests. Susceptibility to trimethoprim + sulfamethoxazole was also examined in only integron-bearing organisms. The antibiotic resistance tests resulted in bacteria being the most resistant against ampicillin (76.29%) and the most sensitive against amikacin (93.56%). Of 232 isolates, 20 (8.6%) coliforms harbored class 1 and/or class 2 integrons. DNA sequencing showed that variable regions of the integrons harbored various gene cassettes; dfrA12, dfrA15, dfrA17, aadA1, aadA2, aadA5, blaOXA-30 and sat2. Integrons were found in bacteria from all sampling areas except 12 and D3. In this study, the determination of bacterial identification of the species of Gram negative bacilli and their Antibiotic Resistance Profiles in the Kucukcekmece Lagoon for the first time was investigated. A finding indicates that there is a heavy fecal pollution in this lagoon environment, which might probably be resulted from the intensive anthropogenic facilities. The risk to public health could be the transfer of antibiotic resistance determinants from the bacterial isolates to normal microbiota bacteria of humans unless the effective precautions such as water treatment plants are taken.

Rectal Carriage of Extended-Spectrum Beta-Lactamase-Producing Gram-Negative Bacilli in Community Settings in Madagascar

BackgroundExtended-spectrum ß-lactamase-producing Enterobacteria (ESBL-PE) emerged at the end of the 1980s, causing nosocomial outbreaks and/or hyperendemic situations in hospitals and long-term care facilities. In recent years, community-acquired infections due to ESBL-PE have spread worldwide, especially across developing countries including Madagascar.ObjectivesThis study aimed to determine the prevalence and risk factors of intestinal carriage of ESBL-PE in the community of Antananarivo.MethodsNon-hospitalized patients were recruited in three health centers in different socio economic settings. Fresh stool collected were immediately plated on Drigalski agar containing 3 mg/liter of ceftriaxone. Gram-negative bacilli species were identified and ESBL production was tested by a double disk diffusion (cefotaxime and ceftazidime +/− clavulanate) assay. Characterization of ESBLs were perfomed by PCR and direct sequencing . Molecular epidemiology was analysed by Rep-PCR and ERIC-PCR.Results484 patients were screened (sex ratio = 1.03, median age 28 years). 53 ESBL-PE were isolated from 49 patients (carrier rate 10.1%). The isolates included Escherichia coli (31), Klebsiella pneumoniae (14), Enterobacter cloacae (3), Citrobacter freundii (3), Kluyvera spp. (1) and Pantoae sp.(1). In multivariate analysis, only the socioeconomic status of the head of household was independently associated with ESBL-PE carriage, poverty being the predominant risk factor.ConclusionsThe prevalence of carriage of ESBL in the community of Antananarivo is one of the highest reported worldwide. This alarming spread of resistance genes should be stopped urgently by improving hygiene and streamlining the distribution and consumption of antibiotics.

Epidemiology And Genetics Of VIM-Type Metallo-β-Lactamases In Gram-Negative Bacilli

Metallo-β-lactamases (MBLs) are a rapidly evolving group of β-lactamases, which hydrolyze most β-lactams including the carbapenems. Of the known MBLs, VIMs are one of the most common families, with 27 variants detected in at least 23 species of Gram-negative bacilli from more than 40 countries/regions. The amino acid similarities of VIM variants range from 72.9 to 99.6% with 1-72 different residues. Most of the bla (VIM)s are harbored by a class 1 integron, a genetic platform able to acquire and express gene cassettes. The integrons are usually embedded in transposons and, in turn, accommodated on plasmids, making them highly mobile. Integrons display considerable diversity, with at least 110 different structures associated with the gain and spread of the bla (VIM)s. In most instances, the bla (VIM)s co-exist with one or more other resistance genes. The processes for the identification of bacteria harboring bla (VIM)s are also discussed in this article.