Evaluation of antimicrobial susceptibility of Enterobacteriaceae causing urinary tract infections in Africa

Trends and predictors of antimicrobial resistance among patients with urinary tract infections at a tertiary hospital facility in Alexandria, Egypt: a retrospective record-based classification and regression tree analysis

BACKGROUND

The incidence of Antimicrobial Resistance (AMR) in uropathogens varies between countries and over time. We aim to study the patterns and potential predictors of AMR among patients with UTIs admitted to the Urology Department at Alexandria University Hospital.

METHODS

An observational retrospective record-based study was conducted on all patients admitted to the Urology department from October 2018 to October 2020. Data collected from patients' records included: demographic data, diagnosis on admission, history of chronic diseases, duration of hospital stay, insertion of a urinary catheter, duration of the catheter in days, history of the use of antibiotics in the previous three months, and history of urinary tract operations. If UTI was documented, we abstracted data about urine culture, use of antibiotics, results of urine cultures, type of organism isolated, and sensitivity to antibiotics. We conducted a multivariable logistic regression model. We performed Classification and Regression Tree Analysis (CART) for predicting risk factors associated with drug resistance among patients with UTI. Data were analyzed using SPSS statistical package, Version 28.0, and R software (2022).

RESULTS

This study encompassed 469 patients with UTIs. The most commonly isolated bacterium was Escherichia coli, followed by Klebsiella pneumoniae. Multidrug resistance (MDR) was found in 67.7% (149/220) of patients with hospital-acquired UTIs and in 49.4% (83/168) of patients with community-acquired UTIs. Risk factors independently associated with antimicrobial resistance according to logistic regression analysis were the use of antibiotics within three months (AOR = 5.2, 95% CI 2.19-12.31), hospital-acquired UTI (AOR = 5.7, 95% CI 3.06-10.76), diabetes mellitus (AOR = 3.8, 95% CI 1.24-11.84), age over 60 years (AOR = 2.9, 95% CI 1.27-6.72), and recurrent UTI (AOR = 2.6, 95% CI 1.08-6.20). Classification and regression tree (CART) analysis revealed that antibiotic use in the previous three months was the most significant predictor for developing drug resistance.

CONCLUSION

The study concluded a high level of antimicrobial resistance as well as significant MDR predictors among hospitalized patients with UTIs. It is vital to assess resistance patterns in our hospitals frequently to improve rational antibiotic treatment as well as to sustain antimicrobial stewardship programs and a rational strategy in the use of antibiotics. Empirical therapy for UTI treatment should be tailored to the potential pathogens' susceptibility to ensure optimal treatment. Strategic antibiotic use is essential to prevent further AMR increases. Further research should focus on suggesting new biological systems or designed drugs to combat the resistance of UTI pathogens.

Bacteriophages PɸEn-CL and PɸEn-HO can eliminate MDR Enterobacter cloacae and Enterobacter hormaechei isolated from burn wound infections without toxicity for human skin cells

The prevalence of multidrug-resistant (MDR) strains has caused serious problems in the treatment of burn infections. MDR Enterobactercloacae and Enterobacterhormaechei have been defined as the causative agents of nosocomial infections in burn patients. In this situation, examination of phages side effects on human cell lines before any investigation on human or animal that can provide beneficial information about the safety of isolated phages. The aim of this study was to isolate and identify the specific bacteriophages on MDR E. cloacae and E. hormaechei isolated from burn wounds and to analyze the efficacy, cell viability and cell cytotoxicity of phages on A-375 and HFSF-PI cell lines by MTT (3-(4, 5-dimethylthiazol-2-yl)2,5-diphenyl-tetrazolium bromide) colorimetric assay and lactate dehydrogenase (LDH) release assay. Phages were isolated from urban sewage Isfahan, Iran. Enterobactercloacae strain Iau-EC100 (GenBank accession number: MZ314381) and E. hormaechei strain Iau-EHO100 (GenBank accession number: MZ348826) were sensitive to the isolated phages. Transmission electron microscopy (TEM) results revealed that PɸEn-CL and PɸEn-HO that were described had the morphologies of Myovirus and Inovirus, respectively. Overall, MTT and LDH assays showed moderate to excellent correlation in the evaluation of cytotoxicity of isolated phages. The results of MTT and LDH assays showed that, phages PɸEn-CL and PɸEn-HO had no significant toxicity effect on A375 and HFSF-PI 3 cells. Phage PɸEn-HO had a better efficacy on the two tested cell lines than other phage. Our results indicated that, there were significant differences between the two cytotoxicity assays in phage treatment compared to control.

Bacteria Causing Community-Acquired Urinary Tract Infections and Their Antibiotic Susceptibility Patterns in Outpatients Attending at a State Hospital in Turkey

Introduction

Clinicians should know the frequency and resistance patterns of bacteria that cause urinary tract infections (UTI) to provide patients with appropriate treatment and antibiotic management. However, the frequency of culture reproducing organisms and resistance patterns change in each community. Therefore, these data must be determined locally to make better treatment decisions. Herein, we aimed to determine the frequency of UTI-causing agents and current antimicrobial resistance profiles in outpatients attending our hospital.

Methods

This retrospective descriptive study included three hundred eight outpatients attending under the diagnosis of UTI between March and October 2020 who had a positive urine culture for bacterial growth. Age, sex, laboratory tests, urinalysis results, microorganisms grown in urine culture, and antibiograms were evaluated from the patients' medical records. Data were analyzed using SPSS version 23.0 (IBM Corp., Armonk, NY) for Windows.

Results

In urine culture results, Escherichia coli (E. coli) and Klebsiella species are the most commonly detected agents. The growth in 71 (23%) of the 308 cultures was extended-spectrum beta-lactamase (ESBL) positive. In the E. coli growths, the susceptibility rates to fosfomycin, gentamicin, nitrofurantoin, trimethoprim-sulfamethoxazole, and ampicillin were 95.2%, 90.3%, 95.3%, 76.8%, and 49.3%, respectively. The susceptibility of Klebsiella species to gentamicin was as high as 93.7%, similar to that of E. coli, whereas its susceptibility rates to fosfomycin, trimethoprim-sulfamethoxazole, and nitrofurantoin were lower than those of E. coli (76.1%, 48.4%, and 68.4%, respectively). Of the 71 ESBL-positive growths, 52 were E. coli (17.3% of all UTIs), and 14 were Klebsiella species (4.6% of all UTIs). Of the ESBL-positive strains, 88.7%, 81%, and 76.1% were susceptible to fosfomycin and nitrofurantoin, respectively, and 64.9% and 45.7% were sensitive to cefoxitin and trimethoprim-sulfamethoxazole.

Conclusion

UTIs are among the most common causes of hospital admission and infections for which empirical antibiotic administration is initiated. The increasing rates of ESBL positivity and resistance to antibiotics such as ampicillin, cephalosporins, trimethoprim-sulfamethoxazole, and quinolones, especially in E. coli and Klebsiella strains, which are the most common pathological agents of UTI in our region, have limited the use of these treatments. However, the high susceptibility of E. Coli growths to fosfomycin and nitrofurantoin and susceptibility of Klebsiella growths to gentamicin may make these antibiotics stand out as suitable options for the empirical treatment of UTI in our setting.

Prevalence of Extended Spectrum Beta-Lactamase Producing Gram-Negative Bacilli causing Surgical Site Infections in a Tertiary Care Centre

Hospital-acquired infections (HAIs) are continuing to be a major risk in health care settings. World Health Organization (WHO) describes surgical site infections (SSIs) as one among the major health issue, causing enormous burden to both patients as well as doctors. Multidrug-resistant pathogens that cause SSIs continue to be an ongoing and increasing challenge to health care settings. The objective of the present study was to know the prevalence of extended-spectrum beta-lactamase (ESBL) producing gram-negative bacilli causing SSIs at a tertiary healthcare facility. The present cross-sectional observational study was done for a period of one year. Pus samples from clinically suspected cases of SSIs were collected and subjected to bacterial culture and sensitivity testing. From the total of 140 samples collected, a total of 138 bacterial isolates were isolated. Out of 138 isolates, 85 isolates (61.6%) were identified as gram-negative bacilli of which 33 isolates (38.8%) were identified to be ESBL phenotypes. Majority of the ESBL phenotypes were Escherichia coli (25.9%) followed by Klebsiella pneumoniae (7%), Acinetobacter species (2.4%), Pseudomonas aeruginosa (2.4%) and Proteus species (1.2%). Regular surveillance of antibiotic sensitivity pattern and screening for beta-lactamase production should be done which helps to know the trends of pathogenic bacteria causing SSI and guides in planning antibiotic therapy.

Not Only Antimicrobial: Metronidazole Mitigates the Virulence of Proteus mirabilis Isolated from Macerated Diabetic Foot Ulcer

Diabetic foot ulcers are recognized to be a severe complication of diabetes, increasing the risk of amputation and death. The bacterial infection of Diabetic foot ulcers with virulent and resistant bacteria as Proteus mirabilis greatly worsens the wound and may not be treated with conventional therapeutics. Developing new approaches to target bacterial virulence can be helpful to conquer such infections. In the current work, we evaluated the anti-virulence activities of the widely used antibacterial metronidazole. The minimum inhibitory concentrations (MIC) and minimum biofilm eradication concentrations (MEBC) were determined for selected antibiotics which P. mirabilis was resistant to them in the presence and absence of metronidazole in sub-MIC. The effect of metronidazole in sub-MIC on P. mirabilis virulence factors as production of exoenzymes, motilities, adhesion and biofilm formation, were evaluated. Furthermore, molecular docking of metronidazole into P. mirabilis adhesion and essential quorum sensing (QS) proteins, was performed. The results revealed a significant ability of metronidazole to in-vitro inhibit P. mirabilis virulence factors and antagonize its essential proteins. Moreover, metronidazole markedly decreased the MICs and MBECs of tested antibiotics. Conclusively, metronidazole in sub-MIC is a plausible anti-virulence and anti-QS agent that can be combined to other antibiotics as anti-virulence adjuvant to defeat aggressive infections.

High Prevalence of Multidrug-Resistant and Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae: A Cross-Sectional Study at Arsho Advanced Medical Laboratory, Addis Ababa, Ethiopia

Background

Multidrug-resistant Enterobacteriaceae particularly extended-spectrum beta-lactamase producers have become a major public health threat. Despite efforts to limit their spread, rates of multidrug-resistance members of the Enterobacteriaceae continue to increase throughout the world causing increased morbidity and mortality and raised costs for medical care.

Objective

The aim of this study was to determine the prevalence of multidrug resistance and extended-spectrum β-lactamase-producing Enterobacteriaceae.

Methods

Four hundred forty Enterobacteriaceae isolates from outpatients referred to Arsho Advanced Medical Laboratory were identified and assessed for their antimicrobial resistance pattern by using the automated VITEK 2 compact system. Extended-spectrum β-lactamase production was determined by the VITEK 2 automated compact system using the extended-spectrum β-lactamase test panel as per the instruction of the manufacturer.

Results

The overall resistance rates of Enterobacteriaceae against cephalosporins, aminoglycosides, and fluoroquinolones were high. Nitrofurantoin with a resistance rate of 14.3% and piperacillin/tazobactam combination with a resistance rate of 17.3% were better active against this group of Gram-negative bacteria. Out of 440 isolates of Enterobacteriaceae, 42.1% were multidrug-resistant of which 34.3% and 8.95% were extensively drug-resistant and pan-drug resistant, respectively. Among 185 multidrug-resistant Enterobacteriaceae, 63.9% of the isolates produced extended-spectrum β-lactamase of which 75.4%, 19.5%, 1.7%, 2.5%, and 0.8% were E. coli, K. pneumoniae, C. freundii, E. cloacae, and P. mirabilis, respectively.

Conclusions

The present study demonstrated high prevalence rates of multidrug-resistant and extended-spectrum-beta-lactamase-producing Enterobacteriaceae. In order to combat these problems, infection control strategy and proper antibiotic policies should be formulated.

Oral amoxicillin and amoxicillin-clavulanic acid: properties, indications and usage

BACKGROUND

Amoxicillin has been in use since the 1970s; it is the most widely used penicillin both alone and in combination with the β-lactamase clavulanic acid.

OBJECTIVES

In this narrative review, we re-examine the properties of oral amoxicillin and clavulanic acid and provide guidance on their use, with emphasis on the preferred use of amoxicillin alone.

SOURCES

Published medical literature (MEDLINE database via Pubmed).

CONTENT

While amoxicillin and clavulanic acid have similar half-lives, clavulanic acid is more protein bound and even less heat stable than amoxicillin, with primarily hepatic metabolism. It is also more strongly associated with gastrointestinal side effects, including Clostridium difficile infection, and, thus, in oral combination formulations, limits the maximum daily dose of amoxicillin that can be given. The first ratio for an amoxicillin-clavulanic acid combination was set at 4:1 due to clavulanic acid's high affinity for β-lactamases; ratios of 2:1, 7:1, 14:1 and 16:1 are currently available in various regions. Comparative effectiveness data for the different ratios are scarce. Amoxicillin-clavulanic acid is often used as empiric therapy for many of the World Health Organization's Priority Infectious Syndromes in adults and children, leading to extensive consumption, when some of these syndromes could be handled with a delayed antibiotic prescription approach or amoxicillin alone.

IMPLICATIONS

Using available epidemiological and pharmacokinetic data, we provide guidance on indications for amoxicillin versus amoxicillin-clavulanic acid and on optimal oral administration, including choice of combination ratio. More data are needed, particularly on heat stability, pharmacodynamic effects and emergence of resistance in 'real-world' clinical settings.

Phenotypic detection of Extended Spectrum β-Lactamases (ESBL) among gram negative uropathogens reveals highly susceptibility to imipenem

Objective:

We aimed to determine antibiotic susceptibility patterns of ESBL- and non-ESBL bacteria isolated from pregnant women with UTI in antenatal wards in Khartoum State, Sudan.

Methods:

This cross-sectional study was conducted during April-July 2016 at different hospitals in Khartoum State. Mid-stream urine samples were obtained from 150 hospitalized pregnant women and cultured on CLED (Cystine Lactose Electrolyte Deficient) agar. Microorganisms were identified using standard microbiological procedures. Isolated Gram-negative bacteria were tested for antibiotic susceptibility and ESBL screening using modified Kirby- Bauer method and Double Disc Synergy Test (DDST) respectively.

Results:

Urine culture revealed positive results in 33/150 (22%) and the most prevalent isolates were Gram negative bacteria (18/33, 54.5%). Among gram-negative bacteria, isolates of E. coli were the most prevalent accounting 66.6% (12/18) followed by K. pneumoniae (4/18, 22.2%) and K. oxytoca (2/18, 11.1%). ESBL was detected in 8/18 (44.4%) of the Gram-negative isolates. Of note, imipenem was the most susceptible antibiotic for ESBL-producer and non-ESBL producer Gram negative isolates, accounting 100% susceptibility for both bacterial groups. Overall susceptibility rates were also high for ciprofloxacin (13/18, 72.2%). In other hand, co-trimoxazole and amoxicillin showed high resistance pattern for ESBL-producer and non-ESBL producer isolates; 27.8%, 44.4% and 38.9%, 38.9% susceptibility rates of co-trimoxazole and amoxicillin for ESBL-producer and non-ESBL producer isolates, respectively.

Conclusions:

Imipenem remains the most powerful option for ESBL- and non-ESBL bacteria causing UTIs in pregnant women. However, due to tremendous increase of antibiotic-resistant, antibiotic-susceptibility testing is recommended as a routine investigation for admitted pregnant women.

Performance of an Easy and Simple New Scoring Model in Predicting Multidrug-Resistant Enterobacteriaceae in Community-Acquired Urinary Tract Infections

Background

Multidrug resistance (MDR) is a growing global problem in bacterial community-acquired urinary tract infections (CUTIs). We aimed to propose an easy-to-use clinical prediction model to identify patients with MDR in CUTI.

Methods

We conducted a retrospective study including 770 patients with documented CUTI diagnosed during 2010–2017. Logistic regression–based prediction scores were calculated based on variables independently associated with MDR. Sensitivities and specificities at various cutoff points were determined, and the area under the receiver operating characteristic curve (AUROC) was computed.

Results

We found MDR Enterobacteriaceae in 372 cases (45.1%). Multivariate analysis showed that age ≥70 years (adjusted odds ratio [aOR], 2.5; 95% confidence interval [CI], 1.8–3.5), diabetes mellitus (aOR, 1.65; 95% CI, 1.19–2.3), history of urinary tract surgery in the last 12 months (aOR, 4.5; 95% CI, 1.22–17), and previous antimicrobial therapy in the last 3 months (aOR, 4.6; 95% CI, 3–7) were independent risk factors of MDR in CUTI. The results of Hosmer-Lemshow chi-square testing were indicative of good calibration of the model (χ² = 3.4; P = .49). At a cutoff of ≥2, the score had an AUROC of 0.71, a sensitivity of 70.5%, a specificity of 60%, a positive predictive value of 60%, a negative predictive value of 70%, and an overall diagnostic accuracy of 65%. When the cutoff was raised to 6, the sensitivity dropped (43%), and the specificity increased appreciably (85%).

Conclusions

We developed a novel scoring system that can reliably identify patients likely to be harboring MDR in CUTI.

Magnitude of Biofilm Formation and Antimicrobial Resistance Pattern of Bacteria Isolated from Urinary Catheterized Inpatients of Jimma University Medical Center, Southwest Ethiopia

Biofilm formation is one of the features of most bacteria. Catheterization in medicine is a source of highly resistant bacterial infections, and those bacteria respond poorly to antimicrobial therapy. Bacterial biofilm features were not described from catheterized inpatients in Ethiopia as its formation is known to afford antimicrobial resistance and challenge patient management. The aim of this study was to isolate catheter-associated urinary bacterial pathogens, their biofilm formation, and antimicrobial susceptibility pattern among inpatients of Jimma University Medical Center (JUMC) in Southwest Ethiopia. A prospective cross-sectional study was conducted among urinary catheterized inpatients of JUMC from February to August 2016. A total of 143 study participants were enrolled consecutively in this study. Urine samples were collected from catheterized patients and processed using a standard bacteriological protocol for isolation and identification. Evaluation of in vitro biofilm formation and antimicrobial susceptibility pattern of uropathogenic bacteria was done using microtiter plates and disk diffusion method, respectively. Data were cleaned, coded, and entered into SPSS version 20 for analysis. All statistical test values of p < 0.05 were considered statistically significant. From all study participants, mean age was 44 years. Sixty bacterial strains were recovered from 57 urinary catheterized inpatients among which 54 of them were monomicrobial (94.7%). The remaining six bacterial strains were recovered from three study participants each with two bacterial isolates. The predominant bacterial isolates were Gram-negative bacteria with E. coli turning out first. About 80% of bacterial isolates were biofilm formers. The majority of the bacteria were resistant to commonly prescribed antimicrobial agents. In conclusion, the majority of bacterial uropathogen isolates were Gram-negative, biofilm formers, and resistant to commonly prescribed antimicrobial agents. Relatively ciprofloxacin, nitrofurantoin, and amikacin were highly effective against most isolated bacteria.

Genomic landscape of extended-spectrum β-lactamase resistance in Escherichia coli from an urban African setting

Objectives

Efforts to treat Escherichia coli infections are increasingly being compromised by the rapid, global spread of antimicrobial resistance (AMR). Whilst AMR in E. coli has been extensively investigated in resource-rich settings, in sub-Saharan Africa molecular patterns of AMR are not well described. In this study, we have begun to explore the population structure and molecular determinants of AMR amongst E. coli isolates from Malawi.

Methods

Ninety-four E. coli isolates from patients admitted to Queen's Hospital, Malawi, were whole-genome sequenced. The isolates were selected on the basis of diversity of phenotypic resistance profiles and clinical source of isolation (blood, CSF and rectal swab). Sequence data were analysed using comparative genomics and phylogenetics.

Results

Our results revealed the presence of five clades, which were strongly associated with E. coli phylogroups A, B1, B2, D and F. We identified 43 multilocus STs, of which ST131 (14.9%) and ST12 (9.6%) were the most common. We identified 25 AMR genes. The most common ESBL gene was bla CTX-M-15 and it was present in all five phylogroups and 11 STs, and most commonly detected in ST391 (4/4 isolates), ST648 (3/3 isolates) and ST131 [3/14 (21.4%) isolates].

Conclusions

This study has revealed a high diversity of lineages associated with AMR, including ESBL and fluoroquinolone resistance, in Malawi. The data highlight the value of longitudinal bacteraemia surveillance coupled with detailed molecular epidemiology in all settings, including low-income settings, in describing the global epidemiology of ESBL resistance.

High prevalence of multidrug resistant Enterobacteriaceae isolated from outpatient urine samples but not the hospital environment in Bo, Sierra Leone

BACKGROUND

The rising level of antimicrobial resistance among bacterial pathogens is one of the most significant public health problems globally. While the antibiotic resistance of clinically important bacteria is closely tracked in many developed countries, the types and levels of resistance and multidrug resistance (MDR) among pathogens currently circulating in most countries of sub-Saharan Africa are virtually unknown.

METHODS

From December 2013 to April 2014, we collected 93 urine specimens from all outpatients showing symptoms of urinary tract infection (UTI) and 189 fomite swabs from a small hospital in Bo, Sierra Leone. Culture on chromogenic agar combined with biochemical and DNA sequence-based assays was used to detect and identify the bacterial isolates. Their antimicrobial susceptibilities were determined using a panel of 11 antibiotics or antibiotic combinations.

RESULTS

The 70 Enterobacteriaceae urine isolates were identified as Citrobacter freundii (n = 22), Klebsiella pneumoniae (n = 15), Enterobacter cloacae (n = 15), Escherichia coli (n = 13), Enterobacter sp./Leclercia sp. (n = 4) and Escherichia hermannii (n = 1). Antimicrobial susceptibility testing demonstrated that 85.7 % of these isolates were MDR while 64.3 % produced an extended-spectrum ß-lactamase (ESBL). The most notable observations included widespread resistance to sulphonamides (91.4 %), chloramphenicol (72.9 %), gentamycin (72.9 %), ampicillin with sulbactam (51.4 %) and ciprofloxacin (47.1 %) with C. freundii exhibiting the highest and E. coli the lowest prevalence of multidrug resistance. The environmental cultures resulted in only five Enterobacteriaceae isolates out of 189 collected with lower overall antibiotic resistance.

CONCLUSIONS

The surprisingly high proportion of C. freundii found in urine of patients with suspected UTI supports earlier findings of the growing role of this pathogen in UTIs in low-resource countries. The isolates of all analyzed species showed worryingly high levels of resistance to both first- and second-line antibiotics as well as a high frequency of MDR and ESBL phenotypes, which likely resulted from the lack of consistent antibiotic stewardship policies in Sierra Leone. Analysis of hospital environmental isolates however suggested that fomites in this naturally ventilated hospital were not a major reservoir for Enterobacteriaceae or antibiotic resistance determinants.

Evolution of antibiotic multiresistance in Escherichia coli and Klebsiella pneumoniae isolates from urinary tract infections: A 12-year analysis (2003-2014)

INTRODUCTION

The aim of this study was to identify multi-drug resistance (MDR) in the main enterobacteriaceae implicated in urinary tract infections (Escherichia coli and Klebsiella pneumoniae) from both, community and hospitalized patients and to analyze the evolution over a 12-year period.

METHODS

Microb Dynamic software was used to analyze the microbiology laboratory database and a chi square test was applied to compare differences in group proportions and to determine the linear trend over 12 years in three different periods: 2003-2006, 2007-2010, 2011-2014. We chose amoxicillin, gentamicin, ciprofloxacin and trimethoprim-sulphamethoxazole as MDR markers.

RESULTS

A total of 39,980 positive urine samples were analyzed, 34,564 (3786 from hospitalized patients and 30,778 from non-hospitalized patients) E. coli isolates, and 5,422 (774 from hospitalized patients and 4,648 from non-hospitalized patients) K. pneumoniae isolates. The prevalence of UTI due to MDR E. coli and MDR K. pneumoniae significantly increased in the period studied, both in hospitalized and outpatients. A higher percentage of MDR E. coli (5.89% in 2007-2010 versus 8.18% in 2011-2014) and MDR K. pneumoniae (2.38% in 2007-2010 versus 9.35% in 2011-2014) was evident and maintained constant over time in hospitalized patients in comparison to non-hospitalized ones. Infection due to MDR ESBL-producing E. coli and K. pneumoniae increased significantly during the last 8 years in both, hospitalized (20% versus 38% and 66.8% versus 82.6%, respectively) and non-hospitalized patients (18.2% versus 23.6% and 51% versus 74.6%, respectively).

CONCLUSIONS

This study includes data of a large sample size of urinary strains isolated over a 12 year period and demonstrates that MDR is an increasing phenomenon of particular importance in the main UTI-causing species.

Acute cholecystitis associated with infection of Enterobacteriaceae from gut microbiota

Acute cholecystitis (AC) is one of the most common surgical diseases. Bacterial infection accounts for 50% to 85% of the disease's onset. Since there is a close relationship between the biliary system and the gut, the aims of this study were to characterize and determine the influence of gut microbiota on AC, to detect the pathogenic microorganism in the biliary system, and to explore the relationship between the gut and bile microbiota of patients with AC. A total of 185 713 high-quality sequence reads were generated from the faecal samples of 15 patients and 13 healthy controls by 16S rRNA gene pyrosequencing. Patients' samples were significantly enriched in Akkermansia, Enterobacter and Escherichia/Shigella group. The healthy controls, however, showed significant enrichment of Clostridiales, Coprococcus, Coprobacillaceae, Paraprevotella, Turicibacter and TM7-3 in their faecal samples. Escherichia coli was the main biliary pathogenic microorganism, among others such as Klebsiella spp., Clostridium perfringens, Citrobacter freundii and Enterobacter cloacae in the bile of the patients. Additionally, the amount of bile endotoxin significantly correlated with the number of Enterobacteriaceae, especially E. coli. Our data indicate that Enterobacteriaceae might play essential role in the pathogenesis and/or progress of AC. This was verified in an in vivo model using a pathogenic E. coli isolated from one of the patients in guinea pigs and observed marked gallbladder inflammation and morphologic changes. This study thus provides insight which could be useful for the prevention, diagnosis and treatment of AC and related diseases by controlling the growth of Enterobacteriaceae to alleviate the infection.

Antibacterial activity of fosfomycin against uropathogens

BACKGROUND

In recent years, the rising rates of resistance to antimicrobial drugs among pathogens have caused great difficulty for clinicians treating infectious diseases. The aim of the study was to assess the curative effect of fosfomycin in treating urinary tract infections (UTIs) in China.

METHODS

We collected clinical isolates of UTIs to determine their susceptibility to fosfomycin by the agar dilution method and to analyze extended-spectrum β-lactamase (ESBL)-producing isolates by the double-disc method on Mueller-Hinton agar. Fosfomycin-modifying enzyme analysis was conducted by PCR. Differences between the different groups were determined by the χ(2) test.

RESULTS

We collected 433 UTI isolates, and the result showed that the susceptibility rates of clinical isolates were all above 80%. Only Klebsiella pneumoniae was fosA positive, with a positive rate of 26.7%. No correlation was found for the resistance between the antibiotic drugs tested and fosfomycin in the other bacteria, except for cefepime, levofloxacin and ciprofloxacin in Enterobacter cloacae and imipenem in K. pneumoniae.

CONCLUSION

Our data suggest that fosfomycin may be a suitable antimicrobial agent for UTI isolates and ESBL-producing bacteria in our hospital.

Community-associated urinary infections requiring hospitalization: risk factors, microbiological characteristics and patterns of antibiotic resistance

OBJECTIVE

Although patients with urinary tract infections (UTIs) are usually managed as outpatients, a percentage of them requires hospitalization. To review risk factors and microbiological characteristics of community-associated UTIs (CAUTIs) requiring hospitalization has been our objective.

MATERIAL AND METHODS

A prospective observational study was carried out from November 2011 to December 2013. Incidence, microbiological characteristics and antibiotic resistance patterns in patients with CAUTIs that required hospitalization were analyzed. Risk factors (including diabetes mellitus, urolithiasis, urinary catheterization) and resistance rates of each pathogen were also analyzed.

RESULTS

Four hundred and fifty seven patients were hospitalized in our department with CAUTI. The mean age was 56.2±19.85 years. Of them, 52.1% patients were women, 19.7% had urinary indwelling catheter and 11.4% have had a previous UTI. The most frequently isolated pathogens were Escherichia coli (60.6%), followed by Klebsiella (9.2%), Enterococcus (8.4%) and Pseudomonas (7.2%). Enterobacteriaceae other than E.coli were more prevalent in male and older patients. On the other side the most frequently isolated pathogen in patients with a previous UTI and a urinary catheter was Entercoccus. The resistance rates E. coli against ampicillin/amoxicillin + β lactamase inhibitor was 23.5%, against third-generation cephalosporins 16.6%, against fluoroquinolones 31.3% and 16.7% against aminoglycosides. 11.4% E. coli strains were producers of extended-spectrum Beta-lactamases (ESBL). Finally, the resistance rates of Enterococcus and Pseudomonas against quinolones were of 50.0% and 61.5%, respectively.

CONCLUSIONS

CAUTIs that require hospitalization are most frequent in older age, male gender, and presence of urinary catheter, with urolithiasis and with previous episodes of UTI. These factors are also related to isolation of pathogens other than E. coli and higher resistance rates.

Clinical and bacteriological efficacy of amikacin in the treatment of lower urinary tract infection caused by extended-spectrum beta-lactamase-producing Escherichia coli or Klebsiella pneumoniae

Urinary tract infections (UTIs) caused by extended-spectrum beta-lactamase (ESBL)-producing bacteria have become a growing problem limiting therapeutic options. The aim of this study was to investigate the clinical and microbiological efficacy of amikacin treatment in adult patients with lower UTIs due to ESBL-producing Escherichia coli (Ec) or Klebsiella pneumonia (Kp). We conducted a retrospective study of 36 outpatients aged >18 years with dysuria or problems with frequency or urgency in passing urine; pyuria and a positive urine culture (10(5) cfu/ml) for ESBL producing Ec or Kp which is also resistant to nitrofurantoin, fosfomycin, quinolones and trimethoprim/sulfamethoxazole, between January 2013 and February 2014. Patients received intramuscular amikacin 15 mg/kg/day for 10 days. Clinical success was defined as disappearance of symptoms. Bacteriological success was defined as sterile control urine cultures. 58.3% of patients were female. Age range was 18-89 years. All of the patients had at least one complicating factor. 77.8% of the isolates were E. coli. Clinical success rate was 97.2%. Overall bacteriological success rates were 91.7% on the 3 day of treatment, 97.1% at the end of the treatment and 94.1% on the 7-10 days after treatment. After 28-32 days following the treatment, reinfection was found in 12% whereas relapse was not determined. Nephrotoxicity was developed in one patient. The clinicians should keep in mind that amikacin treatment is an efficient and safe alternative treatment option before the carbapenem treatment especially in patients with lower UTIs caused by ESBL-producing Ec or Kp that are resistant to all oral antibiotics.