Resistance Patterns Of Gram-negative Bacteria Research Articles

Changing patterns of bacterial profile and antimicrobial resistance in high-risk patients during the COVID-19 pandemic at a tertiary oncology hospital.

The widespread evolution of phenotypic resistance in clinical isolates over the years, coupled with the COVID-19 pandemic onset, has exacerbated the global challenge of antimicrobial resistance. This study aimed to explore changes in bacterial infection patterns and antimicrobial resistance during the COVID-19 pandemic. This study involved the periods before and during COVID-19: the pre-pandemic and pandemic eras. The surveillance results of bacterial isolates causing infections incancer patients at an Egyptian tertiary oncology hospital were retrieved. The Vitek®2 or Phoenix systems were utilized for species identification and susceptibility testing. Statistical analyses were performed comparing microbiological trends before and during the pandemic. Out of 2856 bacterial isolates, Gram-negative bacteria (GNB) predominated (69.7%), and Gram-positive bacteria (GPB) comprised 30.3% of isolates. No significant change was found in GNB prevalence during the pandemic (P = 0.159). Elevated rates of Klebsiella and Pseudomonas species were demonstrated during the pandemic, as was a decrease in E. coli and Acinetobacter species (P < 0.001, 0.018, < 0.001, and 0.046, respectively) in hematological patients. In surgical patients, Enterobacteriaceae significantly increased (P = 0.012), while non-fermenters significantly decreased (P = 0.007). GPB species from either hematological or surgical wards exhibited no notable changes during the pandemic. GNB resistance increased in hematological patients to carbapenems, amikacin, and tigecycline and decreased in surgical patients to amikacin and cefoxitin (P < 0.001, 0.010, < 0.001, < 0.001, and 0.016, respectively). The study highlights notable shifts in the microbial landscape during the COVID-19 pandemic, particularly in the prevalence and resistance patterns of GNB in hematological and surgical wards.

Gram-negative bacteremia, the risk factors, and outcome in children

We aimed to determine the epidemiology and resistance patterns of Gram-negative bacteria, the risk factors and outcome of bloodstream infection (BSI). In all, 412 episodes in children who were hospitalized with the diagnosis of bacteremia were analyzed. The most common microorganisms were Klebsiella spp. (43.9%), Escherichia coli (13.5 %) and Acinetobacter spp. (10.6 %). Among isolates, 41.2 % were multidrug-resistant, 13.5 % were extensively drug-resistant and 0.4 % were pan-drug-resistant. Carbapenem resistance was revealed in 27.6 % of isolates. Carbapenem and colistin resistance increased over the years. The most common risk factors were the presence of a central-venous catheter and pediatric intensive care unit admission. Clinical response and infection-related mortality were significantly different in cases infected with carbapenem-resistant gram-negative (CRGN) vs carbapenem-susceptible gram-negative bacteria. The increase in multi-resistant Klebsiella spp. seems to be the biggest obstacles in fight against nosocomial infections. The increasing number of CRGN infections over the years affects both the clinical response and mortality rate of BSI.

Recent Trends of Antibiotic Resistance Patterns of Gram-negative Bacteria Collected from Clinical Isolates in Dhaka City

Abstract BACKGROUND: Gram-negative bacteria responsible for a significant rise in antimicrobial resistance over the past 20 years. This alarming resistance has been linked to increased mortality and health-care costs, particularly for patients, clinicians, and the health-care system. Gram-negative bacteria cause a wide range of infectious diseases including gastrointestinal tract infections, urinary tract infections, respiratory tract infections, meningitis, typhoid fever, shigellosis, bacteremia, and septicemia. METHODS: A total of 220 different clinical specimens were collected between October 2022 and November 2023 from various renowned diagnostic centers of Dhaka, Bangladesh. According to the study plan, 199 Gram-negative bacterial isolates were collected, transported, and processed in the Microbiology Laboratory of Stamford University Bangladesh. RESULTS: The study found that female patients were predominant than male patients except for the Proteus cases. Escherichia coli was highly resistant to various antibiotics, with resistance levels ranging from 100% to 66%, although colistin was found effective. Azithromycin was the most ineffective antibiotic against Klebsiella, with 100% resistance. Other antibiotics showed high resistance, although colistin and imipenem showed effective sensitivity. High resistance levels were observed in azithromycin, colistin, doxycycline, nalidixic acid, co-trimoxazole, nitrofurantoin, cefuroxime, and amoxyclave for Proteus-infected patients, although some antibiotics showed effective sensitivity. However, Acinetobacter isolates were also found with high resistance levels across all age groups. For Pseudomonas cases, amoxyclav, nitrofurantoin, and cotrimoxazole were the most ineffective antibiotics, but colistin, ceftazidime, piperacillin, meropenem, and amikacin showed satisfactory efficacy. CONCLUSION: The study reveals alarming multidrug resistance in Gram-negative bacteria in Dhaka, raising public health concerns. Age and gender should be considered when selecting antibiotics.

Antimicrobial resistance patterns of Gram-negative bacteria in an Iranian referral pediatric hospital: A present danger of New Delhi metallo-β-lactamase.

Antimicrobial resistance among gram-negative bacteria has been growing, particularly in developing countries, like Iran. The emergence and spread of carbapenem-resistance mechanisms is a major public health concern because no definite treatments have yet been established for this problem. This study aimed to evaluate antibiotic susceptibility of gram-negative bacteria, metallo-β-lactamases (MBLs) and carbapenemase-producing genes, including bla NDM, bla VIM, and bla IMP in patients referred to Children's Medical Center, Tehran, Iran. In this cross-sectional study, a total of 944 gram-negative isolates were tested in the study, and antimicrobial susceptibility testing was performed. Moreover, MBL production of carbapenem-resistant isolates, as well as the presence of bla NDM, bla VIM, and bla IMP, was investigated. The most common gram-negative isolated bacteria were Escherichia coli (489 samples, 52%), followed by Klebsiella pneumoniae (167 samples, 18%), Pseudomonas aeruginosa (101 samples, 11%), Enterobacter spp. (64 samples, 7%), Pseudomonas spp. (35 samples, 4%), Acinetobacter baumannii (18 samples, 2%), and Burkholderia cepacia (17 samples, 2%). Imipenem-resistant was found in 75%, 61%, and 60% of Stenotrophomonas maltophilia, Enterobacter spp., and A. baumannii isolates, respectively. Moreover, the highest resistance to meropenem was observed in S. maltophilia, A. baumannii, P. aeruginosa, and B. cepacia (100%, 96%, 83%, and 61.5%, respectively). Double disk synergy test (DDST) results showed that 112 out of 255 carbapenem-resistant isolates (44%) were MBL-producing ones. The presence of the bla NDM gene was identified in 32 (29%) of MBL-producing isolates, 13 of which were K. pneumoniae, 7 P. aeruginosa, and 7 E. coli, 3 Enterobacter spp., and 2 Klebsiella spp, respectively. The presence of the bla IMP and bla VIM genes was detected in 2 (2%) and 1 (1%) of MBL-producing isolates. These genes were detected in only MBL-producing P. aeruginosa isolates. Our findings suggest the emergence of NDM-producing strains in our hospital, and bla NDM was the most frequently detected carbapenemase gene in MBL-producing P. aeruginosa, K. pneumoniae, and Klebsiella spp. Since such bacteria can easily spread among patients in the hospital, a strong infection control and prevention plan is highly recommended.

2152. Types and Resistance Patterns of Gram-negative Bacteria (GNB) causing Bloodstream Infections (BSIs) in a Neonatal ICU (NICU), 2010-2019

Abstract Background BSIs caused by GNB, particularly with multidrug resistance, cause substantial morbidity and mortality in NICUs worldwide1. We previously reported low overall rates of gentamicin resistance in commonly isolated GNB, i.e., Escherichia coli and Klebsiella species, supporting gentamicin as empiric therapy in our NICU2. Over a decade later, we sought to assess GNB BSI rates and potential changes in GNB resistance patterns.

Susceptibility and Resistance Patterns of Bacteria Isolated from Infected Wounds, Burn, Medical Device Tips and Blood to Doxycycline and Septrin from Patients in the City of Benghazi

Wound infections and septicemia with drug-resistant bacteria lead to higher mortality and morbidity and increased healthcare costs. We aimed to evaluate the prevalence rate of nosocomial bacterial agents with antimicrobial susceptibility patterns in hospitalized and non-hospitalized patients. Samples are collected from the wound pus, burn; medical device tip and blood of male and female patients and are sent for culture and sensitivity to the Microbiology Department of Al Saleem medical laboratory, Benghazi, Libya, from October 2021 to January 2022. Collected blood samples were directly inoculated into brain heart infusion (BHI) broth, while various swabs were collected by Transport medium and both are cultured on Blood agar, Chocolate agar, MacConkey - aerobic and anaerobic blood agar at 35°C, with CO2. The wound pus was the most samples from which bacteria were isolated, followed by medical device tip swabs, and the least isolation was from a blood specimen. 47 of the specimens were culture-positive. Of these Staph aureus, Strep pneumonia and E. coli were the most abundant bacterial identified in clinical samples. According to susceptibility testing results, antibiotic resistance patterns of Gram-negative bacteria showed that the highest resistance rate was against Septrin (74.4%) and the lowest rate, 17.8%, was related to Doxycycline (44.6%) respectively. The isolates from the nosocomial infection in these patients are resistant to Septrin and Doxycycline antibiotics. We recommend that whenever the diagnosis of nosocomial infection is made, a more effective antibiotic treatment be instituted until the susceptibility of the strain is identified.

Resistance Patterns of Gram-Negative Bacteria Recovered from Clinical Specimens of Intensive Care Patients.

Intensive care units are complex environments favoring high resistance in microorganisms. This study evaluated the resistance and the distribution dynamics of resistant Gram-negative bacteria (GNB) in patients admitted to intensive care units. This retrospective, record-based, cross-sectional study analyzed all of the antibiograms of patients admitted to the ICUs. The BD Phoenix system (BD Diagnostics, Sparks, MD, USA) was used for bacterial identification and antimicrobial testing. Clinical and Laboratory Standard Institute recommendations were used for antimicrobial testing. Frequencies and percentages of multidrug and pan-drug resistance were calculated. A total of 570 bacterial growths were observed, out of which 437 (76.7%) were of GNB. K. pneumoniae (21.0%), P. aeruginosa (11.8%), and Staphylococcus aureus (13.2%) were the most frequent disease-causing bacteria in intensive care patients. Resistance rates of 73.2% and 70.1% were observed for third- and fourth-generation cephalosporins, respectively, while 48.2% carbapenem and > 65% fluoroquinolones resistance rates were observed. Amikacin was the most effective antibiotic, with a sensitivity rate of 69.5%. A total of 372 (85.1%) of GNB were multidrug resistant. The majority of infections in intensive care patients are caused by multidrug-resistant (MDR) Gram-negative bacteria. Female gender and advancing age are factors favoring MDR. Enhanced surveillance and strengthening of the antimicrobial stewardship program are warranted.

Gram-Negative Bacteria Isolates and Their Antibiotic-Resistance Patterns in Patients with Wound Infection in Ethiopia: A Systematic Review and Meta-Analysis.

BackgroundAntibiotic resistance (ABR) restricts the armamentarium of health-care providers against infectious diseases due to the emergence of multidrug resistance (MDR), especially in Gram-negative bacteria. This study aimed to determine pooled estimates of Gram-negative bacteria, their resistance profiles, and rates of MDR in patients with wound infection in Ethiopia.MethodsElectronic databases such as PubMed/MEDLINE, EMBASE, Science Direct, Web of Science, and Google Scholar were searched. Original articles, available online from 1988 to 2020, addressing the prevalence and resistance patterns of Gram-negative bacteria in patients with wound infection and written in English were screened. The data were extracted using a format prepared in Microsoft Excel and exported to STATA 14.0 for the outcome analyses.ResultsThe data of 15,647 wound samples, from 36 studies conducted in 5 regions of the country, were pooled. The overall pooled estimate of Gram-negative bacteria was 59% [95% CI: 52–65%, I2 = 96.41%, p < 0.001]. The pooled estimate of Escherichia colirecovered from isolates of 5205 wound samples was 17% [95% CI: 14–20%], followed by Pseudomonas aeruginosa, 11% [95% CI: 9–14%], Klebsiella pneumonia, 11% [95% CI: 9–13%], Proteus mirabilis, 8% [95% CI: 6–10%], Acinetobacter species, 4% [95% CI: 2–6%], Enterobacter species, 4% [95% CI: 3–5%], and Citrobacter species, 3% [95% CI: 2–4%]. Multidrug resistance prevalence estimates of E. coli, K. pneumonia, P. aeruginosa, P. mirabilis, Citrobacter species, Enterobacter species and Acinetobacter species were 76% [95% CI: 66–86%], 84% [95% CI: 78–91%], 66% [95% CI:43–88%], 83% [95% CI:75–91%], 87% [95% CI:78–96%], 68% [95% CI:50–87%] and 71% [95% CI:46–96%], respectively.ConclusionThere was high resistance in Gram-negative bacteria from wound specimens to commonly used antibiotics in Ethiopia. The data warrant the need of regular epidemiological surveillance of antimicrobial resistance and implementation of an efficient infection control program.

Prevalence and Antimicrobial Resistance of Gram-Negative Bacteria Isolates in Shellfish Samples from Two River Estuaries in South-South Nigeria

Antibiotic resistant bacteria pathogens remain the leading cause of shellfish borne diseases and a major health threat to humans worldwide. The objectives of this study were to isolate, identify, and determine the antibiotic resistance patterns of Gram-negative bacteria from shellfish. We analyzed a total of 540 shellfish (117 clams, 88 oysters, and 136 periwinkles) samples collected from different vendors at Iko and Douglas Creeks in Akwa Ibom State, South-South Nigeria. Conventional cultural techniques, morphological, biochemical characteristics, and PCR amplification were used to identify the bacterial isolates. Antibiotic susceptibility tests (Kirby-Bauer disk diffusion method) and ESBL phenotype (disk) of the isolates were performed. One hundred and thirty-five (135) Gram-negative bacteria comprising 5 genera and 14 species were detected at a prevalence of: Alcaligenes faecalis TRB-7 38 (28.2%), Pseudomonas oryzihabitans strain KCB005 16 (11.9%), Paenalcaligenes retgerii strain B5 12 (8.9%) Pseudomonas aeruginosa JB2 10 (7.4%), Providencia stuartii DMC-28b 9 (6.7%), Alcaligenes species TLT151 8 (5.9%), Pseudomonas aeruginosa CIFRI DTSB1 7 (5.2%), Paenalcaligenes species UN24 7 (5.2%), Alcaligenes faecalis BT10 7 (5.2%), Vibrio species strain PrVy108 6 (4.4%), Pseudomonas xiamenensis C10-2 5 (3.7%), Providencia vemicola Bu15_38 4 (2.9%), Pseudomonas anguillisceptica 4029 3 (2.2%), and Pseudomonas aeruginosa N15-01092 3 (2.2%). All tested isolates showed various degrees of resistance to the thirteen antimicrobials evaluated. High levels of resistance (100%) to cefepime and imipenem were expressed by all isolates except the Providencia species. For the EBSL indicators, all isolates apart from Alcaligenes species were resistant (100%) to ceftriaxone. All Vibrio species were susceptible to norfloxacin, nalidixic acid, and ceftazidime. The identification of antibiotic resistant Gram-negative bacteria (GNARB) from shellfish in this study highlights the risk of disseminated multi-drug resistance—a serious public health concern.

Antimicrobial resistance of gram-negative bacteria: A six-year longitudinal study in a hospital in Saudi Arabia

IntroductionIncreasing prevalence of antimicrobial resistance is a major concern especially in light of lack of new antimicrobial agents. Here, we present antibiotic resistance pattern of gram-negative bacteria (GNB) over six years (2013–2018) in a hospital in Saudi Arabia. Materials and MethodsThe study included a report of the cumulative antibiogram of GNB. Interpretation of the antibacterial susceptibility tests was based on the Clinical and Laboratory Standards Institute guidelines and VITEK® 2 system. ResultsThere was a total of 32,890 GNB isolates and the most common were: Escherichia coli (69.8%), Klebsiella pneumoniae (17.2%) and Pseudomonas aeruginosa (12.8%). Antimicrobial susceptibility of P. aeruginosa and E. coli did not change overtime, however, susceptibility to ceftazidime decreased from 92% to 85% in P. aeuroginosa. Yearly antimicrobial susceptibility did not change significantly overtime for K. pneumoniae. ESBL isolates among K. peumoniae and E. coli was about 26% and 20%, respectively (p=0.0068). For ESBL E. coli, the least effective antibiotics were ciprofloxacin (26%) and trimethoprim-sulfamethoxazole (34%). For ESBL K. pneumoniae, gentamicin, ciprofloxacin, trimethoprim-sulfamethoxazole, and nitrofurantoin had poor activity. For K. pneumoniae, both ciprofloxacin (90%) and trimethoprim-sulfamethoxazole (86%) had better coverage than for E. coli. K. pneumoniae showed less susceptibility to nitrofurantoin than E. coli (20% vs. 92%). ConclusionAntibiotic resistance among P. aeruginosa and E. coli did not change overtime (2013–2018) and the rate of ESBL-producing E. coli and K. pneumoniae was high. Thus, continued surveillance is needed.

Current epidemiology of resistance among Gram-negative bacilli in paediatric patients in Turkey.

The increasing incidence of infections caused by drug-resistant Gram-negative organisms has led to a re-emergence worldwide. This study attempted to investigate the changes in resistance of Gram-negative bacteria to different classes of antibiotics and the treatment options for invasive infections. A retrospective study was performed between January 2012 and January 2017 in a Turkish tertiary care university hospital. A total of 302 patients with Gram-negative bacteraemia (n=274; 90.7%) or meningitis (n=28; 9.3%) were identified and their demographic, clinical and microbiological features were evaluated. A total of 302 patients with Gram-negative bacterial infection (bacteraemia or meningitis) were investigated. Klebsiella spp. was the most frequent causative agent (n=119; 39.4%), followed by Escherichia coli (n=67; 22.2%), Acinetobacter spp. (n=42; 13.9%), Pseudomonas spp. (n=41; 13.6%) and Enterobacter spp. (n=33; 10.9%). In total, 115 isolates (38.1%) were multidrug-resistant (MDR), 63 (20.9%) were extensively drug-resistant (XDR) and 6 (2.0%) were pandrug-resistant (PDR). Over the years, peak antibiotic resistance occurred in 2013, with an increase in the following years. These data indicate that the resistance pattern of Gram-negative bacteria may change over the years in hospital settings. Therefore, active surveillance of the resistance patterns of micro-organisms is necessary for better management of infections caused by highly resistant bacteria.

Antimicrobial resistance patterns of Gram-negative bacteria isolated from bloodstream infections in an Iranian referral paediatric hospital: A 5.5-year study.

Bloodstream infections (BSIs) are a major cause of paediatric morbidity and mortality worldwide. This study describes the epidemiology and antimicrobial resistance of Gram-negative bacteria (GNB) from BSIs in children admitted to an Iranian paediatric hospital. Clinical and microbiological data of patients with positive blood cultures were collected from March 2011 to September 2016. Standard laboratory methods were used for blood culture and bacterial identification. Antimicrobial sensitivity was evaluated by the Kirby-Bauer disk diffusion and broth microdilution methods. Of 2325 bacterial pathogens isolated from blood cultures, 41.1% (n=956) were GNB. Most clinical isolates (n=208; 21.8%) were identified in the cardiac intensive care unit. Predominant bacterial isolates were Klebsiella pneumoniae subsp. pneumoniae (n=263; 27.5%), Escherichia coli (n=192; 20.1%), Serratia marcescens (n=151; 15.8%), Pseudomonas aeruginosa (n=111; 11.6%) and Enterobacter spp. (n=100; 10.5%). Enterobacter isolates showed a high level of ampicillin resistance. Escherichia coli were highly resistant to chloramphenicol (100%), cefixime (100%), ceftriaxone (100%) and ampicillin (96%). Cefixime had the least efficacy against Haemophilus spp. (100% resistant). All K. pneumoniae (100%) were ampicillin-resistant. All S. marcescens were ceftazidime-resistant. No Acinetobacter baumannii were resistant to colistin. All P. aeruginosa were resistant to cefotaxime and trimethoprim/sulfamethoxazole. These results demonstrate the increasing trend in antibiotic resistance among GNB associated with BSI in children, emphasising the importance of continuous screening and surveillance programmes for detection of antibiotic resistance in BSI pathogens for selection of appropriate treatment regimens.

Evaluating the resistance pattern of gram-negative bacteria during three years at the nephrology ward of a referral hospital in southwest of Iran.

Background: Gram-negative bacteria are associated with an increase in rates of antibacterial resistance. In most low- and middle-income countries such as Iran, there is no continuous surveillance system for antibiotic resistance. Objective: The purpose of this survey was to determine the pattern of antimicrobial sensitivity of gram-negative bacteria within 3 consecutive years at a nephrology ward of Nemazee hospital in Shiraz. Materials and Methods: During a 3-year period from 2013 to 2015 at the adult nephrology ward, bacteriological data of all biological samples of hospitalized patients in favor of gram-negative microorganisms were analyzed retrospectively. Antimicrobial susceptibility was performed by the Kirby-Bauer disc diffusion method. Results: The most common gram negative bacterium isolated from biological samples was Escherichia coli (43.9%). The highest (86.3%-94.1%) antibacterial resistance rate was associated with Acinetobacter spp. The most frequent resistance was seen with cephalosporins. In contrast to ceftriaxone, ciprofloxacin, and trimethoprim/sulfamethoxazole, nitrofurantoin and aminoglycosides remained their acceptable activity against E. coli. At least three-fourths (75%) of Acinetobacter spp. isolates was resistant to either aminoglycosides or imipenem. All (100%) isolated Acinetobacter spp. and Pseudomonas aeruginosa species were susceptible to colistin. The rate of Acinetobacter spp. and P. aeruginosa resistant to three or more drugs was 81.7% and 74.6%, respectively. Conclusions: The resistant rate of gram negative pathogens to different tested antibacterial agents was considerably high and has increased during the recent three years in our center.

Impact of hospital length of stay on the distribution of Gram negative bacteria and likelihood of isolating a resistant organism in a Canadian burn center

RationaleThe impact of hospital length of stay (LOS) on the distribution and susceptibility of Gram negative bacteria (GNB) causing infection in burn patients remains unexplored. Knowledge of causative pathogens is important in guiding empiric antibiotic therapy. ObjectivesTo characterize the distribution of GNB causing infection and to identify changes in susceptibility with LOS in a tertiary care burn center. MethodsA retrospective review of all admissions to the Ross Tilley Burn Centre at Sunnybrook Health Sciences Centre with clinical cultures yielding GNB (duplicates excluded) between March 12, 2010 to July 17, 2013 was completed. Positive cultures were categorized into 5 clinically relevant time periods (in days) based on specimen collection date relative to the patient's date of admission: 0–7, 7–14, 14–21, 21–28, >28. Chi-square for proportions was used to compare the time periods. ResultsThe proportion of patients with clinical cultures for P. aeruginosa increased with hospital LOS (0–7 days: 8% vs. >28 days: 55%; p<0.05). Conversely, clinical cultures for H. influenzae occurred primarily within the first 7 days of hospitalization (0–7 days: 36% vs. >28 days: 0.7%; p<0.05). Enterobacteriaceae isolation was highest between 7 and 14 days of hospitalization (7–14 days: 62% vs. >28 days: 38%; p<0.05). Antibiotic resistance was directly proportional to hospital LOS (% patients with multidrug resistant GNB increased from 6% [LOS 0–7days] to 44% [LOS>28 days]; p<0.05). ConclusionsThis study provides objective data documenting changes in species and resistance patterns of GNB causing infection in patients admitted to a burn center as a function of hospital LOS; which may support delaying the use of broad spectrum antibiotics (e.g. carbapenems and beta-lactam/beta-lactamase inhibitors) in clinically stable patients.

The Antibiotic Resistance Pattern of Gram-Negative Bacteria in Children Younger Than 24 Months with a Urinary Tract Infection: A Retrospective Single-Center Study over 15 Consecutive Years

Purpose: We investigated trends in antibiotic resistance for gram-negative bacteria in infants with a urinary tract infection (UTI) over 15 years at a single institution. Methods: A retrospective chart review was conducted for children younger than 24 months who visited the emergency room and were diagnosed with a UTI between January 2000 and December 2014. We selected urine culture data that grew Escherichia coli and Klebsiella pneumoniae. Baseline clinical information and results of antimicrobial susceptibility tests were analyzed by dividing the 15-year study time frame into three periods (A: 2000-2004, B: 2005-2009, and C: 20102014). Results: During the study period, 478 applicable children were identified (E. coli, 89.7% and K. pneumoniae, 10.3%). Antibiotic resistance to third-generation cephalosporins was increased from period A to period C (A, 2.1%; B, 8.3%; C, 8.8%; P=0.025). Resistance to quinolones also showed a steady pattern during periods A to C, although it was not statistically significant (A, 7.9%; B, 9.7%; C, 12.4%; P=0.221). The incidence of Extended-spectrum β-lactamase (ESBL)-producing gram-negative bacteria increased from period A to period C (A, 1.4%; B, 7.6%; C, 8.2%; P=0.012). Conclusion: This study revealed that the common uropathogens E. coli and K. pneumoniae experienced increasing resistance rates against third-generation cephalosporins and a constant antibiotic resistance to quinolones in children younger than 24 months. We also showed a recent increased incidence of ESBLproducing gram-negative bacteria in patients with community-acquired UTIs. Therefore, it is necessary to actively surveil resistance in order to properly select empirical antibiotics.

The outcome of non-carbapenem-based empirical antibacterial therapy and VRE colonisation in patients with hematological malignancies.

Febrile neutropenia (FN) is generally a complication of cancer chemotherapy. We retrospectively evaluated the febrile neutropenia episodes and their outcomes with respect to modification rates of non-carbapenem-based empirical antibacterial therapy and vancomycin-resistant enterococcus (VRE) colonisation that caused to VRE bacteremia in patients with hematological malignancies. All consecutive patients, who were older than 14 years of age and developed febrile neutropenia episodes due to hematological malignancies from September 2010 to November 2011 at the hematology department were included into the study. In total, 86 consecutive neutropenic patients and their 151 febrile episodes were evaluated. The mean MASCC prognostic index score was 18,72 ± 9,43. Among 86 patients, 28 patients experienced a total of 30 bacteremia episodes of bacterial origin. Modification rates of both, empirical monotherapy and combination therapies, were found similar, statistically (P = 0,840). Our results suggest that initiating of non-carbapenem based therapy does not provide high response rates in the treatment of febrile neutropenia attacks. Furthermore, non-carbapenem-based empirical therapy provides benefit in regard to cost-effectiveness and antimicrobial stewardship when local antibiotic resistance patterns of gram-negative bacteria are considered. Patients who are colonized with VRE are more likely to develop bacteremia with VRE strains as a result of invasive procedures and severe damage of mucosal barriers observed in this group of patients.

Antimicrobial resistance pattern of Gram-negative bacteria of nosocomial origin at a teaching hospital in the Islamic Republic of Iran

The emergence of antimicrobial resistance is a global problem in the community and in hospitals. Antibiotic resistance of Gram-negative bacteria from nosocomial infections were evaluated during a 6-month period at Shariati teaching hospital, Tehran, Islamic Republic of Iran. Susceptibility tests were performed on 570 Gram-negative isolates obtained from clinical samples of patients infected after at least 72 hours stay in the hospital. Escherichia coli was the most frequently isolated Gram-negative organism (42.6%). The highest rate of resistance in Gram-negative isolates was seen in the intensive care unit, with Acinetobacter spp. as the most resistant organisms. Gentamicin was the most effective antibiotic against E. coli and all other isolates, while ciprofloxacin was also effective against a wide range of other species. Antibiotic resistant Gram-negative nosocomial infection is prevalent in this teaching hospital in Tehran.

Antimicrobial Resistance Patterns of Gram-Negative Bacteria Isolated from Urine Cultures in Almana General Hospital

Antimicrobial Resistance Patterns of Gram-Negative Bacteria Isolated from Urine Cultures in Almana General Hospital

Antimicrobial resistance patterns in urinary isolates from nursing home residents. Fifteen years of data reviewed.

The antibiotic resistance patterns of gram-negative bacteria isolated from nursing home patients between 1983 and 1997 were analysed. Escherichia coli was the most prevalent isolate (48%) followed by Proteus spp. (26%) and other Enterobacteriaceae (20%). During the study period, the susceptibility of E. coli decreased for co-trimoxazole (79% to 62%), increased for nitrofurantoin (79% to 91%) and remained unchanged for amoxycillin (41%). Susceptibility to norfloxacin, available from 1990, decreased from 87% to 71%. Similar trends were observed when the susceptibilities of all gram-negative urinary pathogens were combined. The changes in susceptibility can probably be attributed to the empirical prescribing practices in the nursing homes studied.

Drug resistance patterns of Gram-negative bacteria isolated from food and non-sterile medicines in hospital environments

Contamination of food and non-sterile medicaments was investigated in seven hospitals. Strains of Gram-negative bacilli isolated were identified and tested for resistance to chemotherapeutic agents and metallic salts. Four per cent of 530 samples of medicaments were contaminated with Pseudomonas aeruginosa and 6 per cent with other Gram-negative bacilli. Eighty-two per cent of 38 food samples were contaminated with Ps. aeruginosa and 63 per cent with other Gram-negative bacilli. Gram-negative bacilli showed a high degree of resistance to antibiotics and inorganic salts. Pyocine, serotyping, biotyping, antibiograms and metal resistograms suggested endemicity of Ps. aeruginosa and other Gram-negative bacilli in the hospitals.