Antimicrobial susceptibilities of aerobic and facultative gram-negative bacilli isolated from Chinese patients with urinary tract infections between 2010 and 2014

Therapeutic strategies for uncomplicated cystitis in women

Uncomplicated cystitis is affecting many women of all ages and has a great impact on the quality of life, especially in women suffering from recurrent, uncomplicated cystitis. By far the most frequent uropathogen, E. coli, may have acquired increasing resistance against a variety of oral antibiotics, which may differ between countries and regions. Therefore, local resistance data are important to be considered. On the other hand, non-antibiotic therapy has also become an option which should be discussed and offered to the patient. In patients suffering from recurrent uncomplicated cystitis, individual risk factors and possible behavioral changes should first be taken into account. Non-antimicrobial prophylactic strategies shown to be successful in well-designed clinical studies are the next options. Long term antibiotic prophylaxis, however, should only be considered as a last option. For some of those patients self-diagnosis and self-treatment may be suitable, e.g. by using a recognized questionnaire.

Discovery of Antimicrobial Agents Based on Structural and Functional Study of the Klebsiella pneumoniae MazEF Toxin-Antitoxin System

Klebsiella pneumoniae causes severe human diseases, but its resistance to current antibiotics is increasing. Therefore, new antibiotics to eradicate K. pneumoniae are urgently needed. Bacterial toxin-antitoxin (TA) systems are strongly correlated with physiological processes in pathogenic bacteria, such as growth arrest, survival, and apoptosis. By using structural information, we could design the peptides and small-molecule compounds that can disrupt the binding between K. pneumoniae MazE and MazF, which release free MazF toxin. Because the MazEF system is closely implicated in programmed cell death, artificial activation of MazF can promote cell death of K. pneumoniae. The effectiveness of a discovered small-molecule compound in bacterial cell killing was confirmed through flow cytometry analysis. Our findings can contribute to understanding the bacterial MazEF TA system and developing antimicrobial agents for treating drug-resistant K. pneumoniae.

Antibiotic resistances of Pseudomonas aeruginosa and Acinetobacter baumannii in urine cultures: experience in a hospital of Southeast Spain

The objectives of this study were to perform a systematic review of publications between 2010 and 2021 on the antibiotic resistance of Pseudomonas aeruginosa and Acinetobacter baumannii from urinary tract infections and to analyze changes over time in hospital urine cultures from 2016 through 2021. The literature was searched, and a retrospective cross-sectional descriptive study was performed in the hospital. Out of 21 838 positive urine cultures, 3.86% were due to P. aeruginosa and 0.44% were due to A. baumannii. For P. aeruginosa, lower resistance rates were observed to virtually all tested antibiotics than were obtained in the systematic review, and the present series of hospital samples showed an in vitro resistance rate <10% to ceftazidime, cefepime, meropenem, piperacillin-tazobactam, amikacin, tobramycin, and colistin. For A. baumannii, the resistance rates to almost all antibiotics were higher in the present series than in the systematic review, being lowest to colistin (10%). Both microorganisms show reduced in vitro susceptibility to some antibiotics during the years of the COVID-19 pandemic in comparison to previous years. In our setting, both piperacillin-tazobactam and meropenem can be recommended for the empirical treatment of UTIs by P. aeruginosa, whereas only colistin can be recommended for UTIs by A. baumannii.

Antibiotic susceptibility pattern, risk factors, and prediction of carbapenem-resistant Pseudomonas aeruginosa in patients with nosocomial pneumonia

Objectives

This study was aimed at describing antibiotic susceptibility patterns and developing a predictive model by assessing risk factors for carbapenem-resistant Pseudomonas aeruginosa (CRPA).

Methods

A retrospective case-control study was conducted at a teaching hospital in China from May 2019 to July 2021. Patients were divided into the carbapenem-susceptible P. aeruginosa (CSPA) group and the CRPA group. Medical records were reviewed to find an antibiotic susceptibility pattern. Multivariate analysis results were used to identify risk factors and build a predictive model.

Results

A total of 61 among 292 patients with nosocomial pneumonia were infected with CRPA. In the CSPA and CRPA groups, amikacin was identified as the most effective antibiotic, with susceptibility of 89.7%. The CRPA group showed considerably higher rates of resistance to the tested antibiotics. Based on the results of mCIM and eCIM, 28 (45.9%) of 61 isolates might be carbapenemase producers. Independent risk factors related to CRPA nosocomial pneumonia were craniocerebral injury, pulmonary fungus infection, prior use of carbapenems, prior use of cefoperazone-sulbactam, and time at risk (≥15 d). In the predictive model, a score >1 point indicated the best predictive ability.

Conclusions

CRPA nosocomial pneumonia could be predicted by risk factor assessment particularly based on the underlying disease, antimicrobial exposure, and time at risk, which could help prevent nosocomial pneumonia.

Epidemiology, drug resistance analysis and mortality risk factor prediction of gram-negative bacteria infections in patients with allogeneic hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an effective treatment for many malignant and refractory diseases. However, infections, as the most common complication after transplantation, often lead to poor long-term prognosis of patients. In this study, we collected electronic medical records of allo-HSCT recipients with gram-negative bacteria (GNB) infections between January 2012 and September 2021, analyzed epidemiological characteristics and antibiotic sensitivity, and determined independent risk factors for carbapenem-resistant GNB (CR-GNB) infections and death by Logistic and Cox regression models. During the 9-year period, 183 of 968 patients developed GNB infections, of which 58 died. The most common pathogen was Klebsiella pneumoniae. CR-GNB, especially carbapenem-resistant Klebsiella pneumonia (CRKP), carbapenem-resistant Acinetobacter baumannii (CRAB) and carbapenem-resistant Escherichia coli (CREC) had a high resistance rate to commonly used clinical antibiotics. Independent risk factors for CR-GNB infections were use of carbapenem antibiotics for >3 days one month before transplantation (OR = 3.244, 95% CI 1.428-7.369, P = 0.005), use of special immunosuppressants after transplantation (OR = 1.21, 95% CI 1.008-1.452, P = 0.041), and time of hematopoietic reconstruction >20 days (OR = 2.628, 95% CI 1.369-5.043, P = 0.004). Independent risk factors for mortality were interval between diagnosis and transplantation >180 days (HR = 2.039, 95% CI 1.05 to 3.963, P = 0.035), total bilirubin levels during infection >34.2 μmol/L (HR = 3.39, 95% CI 1.583-7.256, P = 0.002) and septic shock (HR = 5.345, 95% CI 2.655-10.761, P = 0.000). In conclusion, GNB has a high incidence and mortality in allo-HSCT recipients. Early transplantation for eligible patients, attention to liver function protection, timely identification and treatment of septic shock can help to improve the prognosis of patients.

Analysis of the Distribution and Drug Resistance of Pathogens in Patients with Urinary Tract Infection in the Eastern Chongming Area of Shanghai from 2018 to 2020

Purpose

The aim of this study was to clarify the distribution and drug resistance of pathogens causing urinary tract infection (UTI) and to provide a scientific reference for the rational application of antibiotics.

Patients and Methods

The results of bacterial identification and drug sensitivity analysis of midstream urine samples in our hospital from January 2018 to December 2020 were retrospectively analyzed. The data were analyzed using WHONET 5.6 and SPSS 26.0 (IBM) software.

Results

In all, 1786 pathogens were isolated from 13,141 midstream urine culture samples. Of these, 1093 (61.2%) were gram-negative bacteria, mainly Escherichia coli [29.1%] and Klebsiella pneumoniae [14.3%]; 543 (30.4%) were gram-positive bacteria, mainly Enterococcus faecium [16.7%] and Enterococcus faecalis [8.4%]; and 150 (8.4%) were fungal isolates, with the most common being Candida albicans (3.7%). The resistance rates of E. coli to piperacillin/tazobactam (3.4% vs 10.0%, p<0.05), ampicillin/sulbactam (43.0% vs 53.8%, p<0.05), and ciprofloxacin (58.0% vs 72.9%, p<0.05) increased significantly. K. pneumoniae was highly sensitive to ertapenem (100%). Two Enterococcus spp were highly sensitive to tigecycline (100%), and a small number of norvancomycin-resistant strains were found. The drug resistance rate of E. faecium to quinupristin was 6.7%. The drug resistance rates of E. faecalis to furantoin and ampicillin were 4.0% and 4.7%, respectively.

Conclusion

The pathogens that cause UTIs in patients are diverse, with the most common being E. coli. The isolated pathogens exhibited different resistance patterns. Antibiotics should be rationally selected based on the resistance patterns of the pathogens.

A global perspective on improving patient care in uncomplicated urinary tract infection: Expert consensus and practical guidance

BACKGROUND

Uncomplicated urinary tract infections (uUTIs) are a common problem in women. Management is mainly based on empirical prescribing, but there are concerns about overtreatment and antimicrobial resistance (AMR), especially in patients with recurrent uUTIs.

METHODS

A multidisciplinary panel of experts met to discuss diagnosis, treatment, prevention, guidelines, AMR, clinical trial design, and the impact of COVID-19 on clinical practice.

RESULTS

Symptoms remain the cornerstone of uUTI diagnosis, and urine culture is necessary only when empirical treatment fails, or rapid recurrence of symptoms or AMR is suspected. Specific antimicrobials are first-line therapy (typically nitrofurantoin, fosfomycin, trimethoprim-sulfamethoxazole, and pivmecillinam; dependent on availability and local resistance data). Fluoroquinolones are not first-line options for uUTIs due primarily to safety concerns, but also rising resistance rates. High-quality data to support most non-antimicrobial approaches are lacking. Local AMR data specific to community-acquired uUTIs are needed, but representative information is difficult to obtain; instead, identification of risk factors for AMR can provide a basis to guide empirical antimicrobial prescribing. The COVID-19 pandemic has impacted management of uUTIs in some countries and may have long-lasting implications for future models of care.

CONCLUSIONS

The management of uUTIs in women can be improved without increasing complexity, including simplified diagnosis, and empirical antimicrobial prescribing based on patient characteristics, including review of recent antimicrobial use and past pathogen resistance profiles, drug availability, and guidelines. Current data for non-antimicrobial approaches are limited. The influence of COVID-19 on telehealth could provide an opportunity to enhance patient care in the long term.

Urine Culture in Hospitalized Patients during 2014-2018: An Analysis on Pathogen Distribution and Drug Sensitivity

Objective

We sought to analyze the distribution and antibiotic sensitivity of pathogens in hospitalized patients and to provide a scientific reference for the rational application of antibiotics.

Methods

From January 2014 to December 2018, urine cultures from patients in our hospital were collected and analyzed retrospectively for the presence, distribution, and drug sensitivity of pathogens.

Results

A total of 42,854 midstream urine cultures were collected from which 11,891 (27.75%) pathogens were isolated, including 8101 (68.13%) strains of gram-negative bacteria, 2580 (21.69%) strains of gram-positive bacteria, and 1210 (10.18%) strains of fungi. Escherichia coli and Enterococci were the most common species of gram-negative and gram-positive bacteria, respectively. Drug sensitivity varied among different pathogens. Clear drug resistance was observed in bacteria, while fungus exhibited relatively lower resistance.

Conclusion

Pathogens responsible for urinary tract infections in hospitalized patients are diversiform and display resistance to some antibiotics. Drug resistance monitoring should be enhanced to optimize antimicrobial therapy.

High Prevalence of Extended-Spectrum Beta-Lactamases in Escherichia coli Strains Collected From Strictly Defined Community-Acquired Urinary Tract Infections in Adults in China: A Multicenter Prospective Clinical Microbiological and Molecular Study

Objective

The objective of the study was to investigate the antimicrobial susceptibility and extended-spectrum beta-lactamase (ESBL) positive rates of Escherichia coli from community-acquired urinary tract infections (CA-UTIs) in Chinese hospitals.

Materials and Methods

A total of 809 E. coli isolates from CA-UTIs in 10 hospitals (5 tertiary and 5 secondary hospitals) from different regions in China were collected during the period 2016–2017 according to the strict inclusion criteria. Antimicrobial susceptibility testing was carried out by standard broth microdilution method. Isolates were categorized as ESBL-positive, ESBL-negative, and ESBL-uncertain groups according to the CLSI recommended phenotypic screening method. ESBL and AmpC genes were amplified and sequenced on ESBL-positive and ESBL-uncertain isolates.

Results

The antimicrobial agents with susceptibility rates of greater than 95% included imipenem (99.9%), colistin (99.6%), ertapenem (98.9%), amikacin (98.3%), cefmetazole (97.9%), nitrofurantoin (96%), and fosfomycin (95.4%). However, susceptibilities to cephalosporins (varying from 58.6% to 74.9%) and levofloxacin (48.8%) were relatively low. In the phenotypic detection of ESBLs, ESBL-positive isolates made up 38.07% of E. coli strains isolated from CA-UTIs, while 2.97% were ESBL-uncertain. Antimicrobial susceptibilities of imipenem, cefmetazole, colistin, ertapenem, amikacin, and nitrofurantoin against ESBL-producing E. coli strains were greater than 90%. The percentage of ESBL-producing strains was higher in male (53.6%) than in female patients (35.2%) (p < 0.001). CTX-M-14 (31.8%) was the major CTX-M variant in the ESBL-producing E. coli, followed by CTX-M-55 (23.4%), CTX-M-15 (17.5%), and CTX-M-27 (13.3%). The prevalence of carbapenem-resistant E. coli among CA-UTI isolates was 0.25% (2/809).

Conclusion

Our study indicated high prevalence of ESBL in E. coli strains from strictly defined community-acquired urinary tract infections in adults in China. Imipenem, colistin, ertapenem, amikacin, and nitrofurantoin were the most active antimicrobials against ESBL-positive E. coli isolates. bla_CTX–M–14 is the predominant esbl gene in ESBL-producing and ESBL-uncertain strains. Our study indicated that the use of cephalosporins and fluoroquinolone needs to be restricted for empirical treatment of CA-UTIs in China.

Eight-Year Surveillance of Uropathogenic Escherichia coli in Southwest China

Purpose

To assess antimicrobial resistance profiles change in uropathogenic Escherichia coli (UPEC) during an 8-year period, especially extended-spectrum β-lactamase (ESBL)-producing and carbapenem-resistant isolates.

Materials and Methods

A retrospective observational study of urinary tract infections (UTIs) was performed in a territory hospital between 2012 and 2019. Isolates were identified using matrix-assisted laser desorption/ionization time of flight mass spectrometry or the VITEK 2 Compact system. The antimicrobial susceptibility testing was performed using the VITEK 2 Compact system and the modified Kirby-Bauer disc diffusion method.

Results

Of the 7713 non-repetitive UPEC isolates, 7075 (91.7%) were from inpatients and 638 (8.3%) were from outpatients. The prevalence of ESBL declined from 62.5% to 49.7% (P = 0.003). Except for cefoxitin, the resistance rates of ESBL-producing isolates were mostly higher than that of non-ESBL-producing isolates (P < 0.001). The resistance rates of ampicillin (P = 0.013), ampicillin/sulbactam (P = 0.013), ceftriaxone (P < 0.001), gentamycin (P = 0.001), tobramycin (P = 0.011), and trimethoprim/sulfamethoxazole (P = 0.028) declined slightly, while the resistance rate of imipenem increased slightly (P = 0.001). The prevalence of carbapenem-resistant Escherichia coli was <2.0%.

Conclusion

ESBL-producing Escherichia coli is still the main drug-resistant bacteria causing UTIs. We should pay attention to antimicrobial resistance in high-risk inpatient areas and take effective measures to prevent and control nosocomial infections.

A 7-year surveillance of the drug resistance in Klebsiella pneumoniae from a primary health care center

Background

The increased prevalence of Klebsiella pneumoniae infections and resistance rates are a current cause for concern. However, data for resistance rates in K. pneumoniae strains from primary hospitals and the resistance distribution among the different isolate sample sources are scarce.

Methods

All the K. pneumoniae strains were isolated from patients who visited a primary health care center located in Central Zhejiang Province from January 2011 to December 2017. The specimens included blood, sputum, cervical secretions and urine. The species were identified by the Vitek 2 Compact Bacterial Identification and Monitoring System or VITEK-MS and the extended spectrum β-lactamase (ESBL) and drug resistance profiles were identified using the AST-GN13 Gram negative susceptibility card (VITEK-2). The genotype of strains from urine sources was analyzed by detecting TEM and SHV genes. Finally, the drug resistance rates among the isolates from different sample sources were analyzed using the Chi square test with SPSS software.

Results

A total of 5319 K. pneumoniae strains were isolated in this study. Among the 20 antimicrobial drugs studied, the resistance rates of K. pneumoniae strains varied from 1.4% (ertapenem) to 23.1% (nitrofurantoin). The antibiotic resistance rates varied significantly among the isolate samples sources for all, with the highest rates for all antibiotics except for nitrofurantoin found in urine samples. In addition, the ESBL-positive rate in urine samples was 27.1%, significantly higher than that of cervical secretions (20.2%), blood (16.5%) and sputum (15.2%). Compared to the ESBL-negative strains, higher resistance rates were detected in the ESBL-positive strains. The most common genotype of isolates from urine was SHV (28%, 23/82), following by TEM (14.6%, 12/82).

Conclusion

The highest resistance rates of K. pneumoniae strains to most antibiotics found in urine samples are partly due to the ESBLs, indicating that a special attention should be paid in the treatment of urinary tract infection.

Antibiotic resistance, virulence and genetic diversity of Klebsiella pneumoniae in community- and hospital-acquired urinary tract infections in Iran

Klebsiella pneumoniae is among the most important causes of urinary tract infection (UTI). The aim of this study was to investigate the prevalence and correlation of antibiotic resistance with virulence characteristics and genetic diversity in K. pneumoniae isolated from UTIs in Iran. Phenotypic tests and antibiotic susceptibility were carried out on the isolates. Detection of the virulence and extended-spectrum β-lactamase (ESBL) genes was performed by polymerase chain reaction. Pulsed-field gel electrophoresis (PFGE) was used for exploring the genomic relatedness. Hemolysin, biofilm, and hypermucoviscosity formation were observed in 87.1%, 86.4%, and 12.1% of isolates, respectively. The antibiotic resistance rate of K. pneumoniae isolates ranged from 12.1% for meropenem to 100% for amoxicillin. The prevalence of virulence genes ranged from 1.4% for cnf-1 to 100% for mrkD, fimH, kpn, and entB genes. In this study, 91.7%, 33.3%, and 4.2% of phenotypically ESBL-producers were positive for bla_CTX-M, bla_TEM, and bla_SHV genes, respectively. An association was observed between the presence of traT, fyuA, or cnf-1 genes with antibiotic resistance. Two clone types were obtained by PFGE that indicate different K. pneumoniae clones in community- and hospital-acquired UTIs. The findings of this study are valuable in development of treatment strategies against UTIs in Iran.

Escherichia coli O25b-ST131 and O16-ST131 causing urinary tract infection in women in Changsha, China: molecular epidemiology and clinical characteristics

Objective

This study aimed to investigate the prevalence of Escherichia coli ST131 and molecularly characterize the O25b-ST131 and O16-ST131 subgroups among urinary tract infection (UTI) E. coli isolates from women in central China. We also assessed the clinical characteristics and outcomes of infections caused by E. coli ST131.

Methods

Between January 2014 and December 2015, a total of 216 consecutive, non-repetitive E. coli isolates were recovered from UTI urine samples from women in Changsha, China. All isolates were analyzed for phylogenetic groups, antimicrobial resistance and virulence genotypes. ST131 clonal groups were identified using PCR and characterized using O serotyping, CTX-M genotypes, fimH, gyrA, and parC alleles, fluoroquinolone resistance genes and pulsed-field gel electrophoresis (PFGE). Clinical data were obtained from medical records.

Results

Overall, 41 (19.0%) of 216 E. coli isolates were identified to contain ST131 strains, among which 27 were O25b-ST131 strains and 14 were O16-ST131 strains. The clinical characteristics and outcomes of the ST131 group did not differ significantly from those of the non-ST131 group, except for the presence of urinary stones (43.9% vs 27.4%, P=0.039). Ciprofloxacin resistance was found to be significantly higher in O25b-ST131 isolates than O16-ST131 isolates (96.3% vs 14.3%, P<0.001). The majority of O25b-ST131 isolates belonged to fimH30 (92.6%), followed by fimH41 (3.7%) and fimH27 (3.7%). O25b-H30 and O25b-H41 isolates were resistant to ciprofloxacin, and possessed gyrA1AB/parC1aAB combination. All of the O16-S131 isolates were found to belong to fimH41, and of which, two of the ciprofloxacin-resistant strains harbored gyrA1AB/parC3A combination. Three PFGE clusters, consisting of 38 (92.7%) isolates, with more than 70% similarity were identified.

Conclusion

The O25b and O16 sub-lineages have emerged as an important group of E. coli ST131 in UTI isolates from women in China. UTI patients with a history of urinary stones may need to be particularly vigilant against ST131 infection.

An update on antimicrobial resistance and the role of newer antimicrobial agents for Pseudomonas aeruginosa

Infections due to Pseudomonas aeruginosa is a major health concern, especially hospital-acquired infections, in critically ill individuals. Antimicrobial resistance (AMR) increases the morbidity and mortality rates associated with pseudomonal infections. In this review, we aim to address two major aspects of P. aeruginosa. The first part of the review will focus on the burden of AMR and its prevailing mechanisms seen in India, while the second part will focus on the challenges and approaches in the management with special emphasis on the role of newer antimicrobial agents.

Carbapenem susceptibilities of Gram-negative pathogens in intra-abdominal and urinary tract infections: updated report of SMART 2015 in China

Background

To evaluate the susceptibility rates of aerobic and facultative Gram-negative bacterial isolates from Chinese intra-abdominal infections (IAI) and urinary tract infections (UTI) focusing on carbapenems and comparing their effectiveness between 2014 and 2015.

Methods

A total of 2318 strains in 2015 (1483 from IAI and 835 from UTI) and 2374 strains in 2014 (1438 from IAI and 936 from UTI) were included in the analysis. Antimicrobial susceptibilities were determined at a central laboratory using CLSI broth microdilution and interpretive standards. Hospital acquired (HA) IAI and UTI were defined as isolates sampled > 48 h and community acquired (CA) as isolates sampled < 48 h after admission.

Results

The main species derived from IAI and UTI in 2015 were Escherichia coli (50.86%) and Klebsiella pneumoniae (19.20%). Susceptibilities of Escherichia coli IAI and UTI strains to imipenem (IPM) and ertapenem (ETP) were > 90% in 2014 and 2015, while the susceptibilities to IPM and ETP of Klebsiella pneumoniae IAI strains were >  80% in 2014 but dropped to ≤80% in 2015 for UTI strains. Susceptibilities of IAI Enterobacteriaceae strains to IPM and ETP in 2015 were lowest in the colon and abscesses, and Enterobacteriaceae susceptibilities of UTI and IAI isolates to IPM and ETP were lowest in medical, pediatric and surgery intensive care units (ICUs) in 2015.

Conclusions

IPM and ETP were effective in vitro against Enterobacteriaceae isolated from IAIs and UTIs in 2014 and 2015, but susceptibility to carbapenems in UTIs markedly decreased in 2015.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3405-1) contains supplementary material, which is available to authorized users.

Relationship Between Biofilm Formation and Antimicrobial Resistance in Gram-Negative Bacteria

Gram-negative microorganisms are a significant cause of infection in both community and nosocomial settings. The increase, emergence, and spread of antimicrobial resistance among bacteria are the most important health problems worldwide. One of the mechanisms of resistance used by bacteria is biofilm formation, which is also a mechanism of virulence. This study analyzed the possible relationship between antimicrobial resistance and biofilm formation among isolates of three Gram-negative bacteria species. Several relationships were found between the ability to form biofilm and antimicrobial resistance, being different for each species. Indeed, gentamicin and ceftazidime resistance was related to biofilm formation in Escherichia coli, piperacillin/tazobactam, and colistin in Klebsiella pneumoniae, and ciprofloxacin in Pseudomonas aeruginosa. However, no relationship was observed between global resistance or multidrug-resistance and biofilm formation. In addition, compared with other reported data, the isolates in the present study showed higher rates of antimicrobial resistance. In conclusion, the acquisition of specific antimicrobial resistance can compromise or enhance biofilm formation in several species of Gram-negative bacteria. However, multidrug-resistant isolates do not show a trend to being greater biofilm producers than non-multiresistant isolates.