Antibiotic susceptibility of bacterial strains isolated from patients with community-acquired urinary tract infections

Antibacterial and antibiofilm efficacy of Ag NPs, Ni NPs and Al2O3 NPs singly and in combination against multidrug-resistant Klebsiella pneumoniae isolates

BACKGROUND

Although traditional antibiotic therapy provided an effective approach to combat pathogenic bacteria, the long-term and widespread use of antibiotic results in the evolution of multidrug-resistant bacteria. Recent progress in nanotechnology offers an alternative opportunity to discover and develop novel antibacterial agents.

METHODS

A total of 51 K. pneumoniae strains were collected from several specimens of hospitalized patients and identified by two parallel methods (biochemical tests and Vitek-2 system). The antibiotic sensitivity of isolates was evaluated by disk diffusion antibiogram and Vitek-2 system. The biofilms formation ability of antibiotic-resistant strains was examined by microtiter plate and tube methods based on crystal violet staining. The molecular technique was used to determine key genes responsible for biofilms formation of clinical isolates. The antibacterial and antibiofilm activities of Ag NPs, Ni NPs, Al₂O₃ NPs singly (NPs) and in combination (cNPs) were investigated against selected strains using standard methods. Moreover, the cytotoxicity of NPs was evaluated on mouse neural crest-derived (Neuro-2A) cell line.

RESULTS

The results of bacterial studies revealed that more than 80 % of the isolates were resistant to commonly used antibiotics and about 95 % of them were able to form biofilms. Moreover, the presence of fimA and mrkA genes were determined in all biofilm-producing strains. The results of antibacterial and antibiofilm activities of NPs and cNPs demonstrated the lower MIC and MBEC values for Al₂O₃ NPs singly as well as for Ag/Ni cNPs and Ag/Al₂O₃ cNPs in combination, respectively. Overall, the inhibitory effects of cNPs were superior to NPs against all strains. Furthermore, the results of the checkerboard assays showed that Ag NPs act synergistically with two other NPs against multidrug-resistant Klebsiella pneumoniae (MDR-K. pneumoniae) isolates. The in vitro cytotoxicity assay revealed no significant toxicity of NPs against Neuro-2A cells.

CONCLUSION

In the present study, the combination of Ag NPs, Ni NPs, and Al₂O₃ NPs were used against MDR-K. pneumoniae strains and antibacterial and antibiofilm activities were observed for Ag/Ni cNPs and Ag/Al₂O₃ cNPs.

Bacterial Quality of Urinary Tract Infections in Diabetic and Non Diabetics of the Population of Ma'an Province, Jordan

BACKGROUND AND OBJECTIVE

The patients with Diabetes Mellitus (DM) have malfunction in bladder which prompt urine accumulation in its pool which serves a decent situation to the microbes to be develop and cause Urinary Tract Infection (UTI). The UTI is the most infectious disease that affects both males and females. This study was designed to detect the bacterial species responsible for UTI in both diabetic and non-diabetic patients in Ma'an province, Jordan.

MATERIALS AND METHODS

One hundred sixteen urine samples were investigated to determine UTI-causing bacteria. These samples distributed unequally between diabetic male (12) and diabetic female (25) and also non-diabetic male (13) and non-diabetic female (66).

RESULTS

It was observed that E. coli is responsible for large proportion (44.8%) of UTI in both diabetic (15.5%) and non-diabetic (29.3%) patients. This study showed inequality in the bacterial species that were isolated from both diabetic and non-diabetic samples. However, five bacterial species including E. aerogenes, E. cloacae, C. freundii, A. baumannii and B. subtilis did not exist in all diabetic samples. Treatment of UTI in both diabetic and non-diabetic patients with chloramphenicol (30 μg), ciprofloxacin (5 μg) and vancomycin (30 μg) resulted in more favorability than other antibiotics. At the same time cephalothin (30 μg) was not recommended.

CONCLUSION

Escherichia coli was the prevailing bacterial infections among those which were isolated from patients with UTI. Certain forms of bacterial infections inclined to be extra common in diabetic patients than others and other infections may be more severe in people with diabetics than in non diabetics.

Etiological and Resistance Profile of Bacteria Involved in Urinary Tract Infections in Young Children

Background. The objective of this study was to identify the bacteria most frequently responsible for urinary tract infection (UTI) in the population of under-2-year-olds in our geographic area and to evaluate the activity of antibiotics widely used for UTI treatment during a 4-year study period. Materials and Methods. A retrospective analysis was conducted of data on the identification and susceptibility of microorganisms isolated in urine samples from children under 2 years of age. Results. A total of 1,045 uropathogens were isolated. Escherichia coli accounted for the majority (60.3%) of these, followed by Enterococcus faecalis (22.4%) and Klebsiella spp. (6.5%). The highest E. coli susceptibility rates (>90%) were to piperacillin-tazobactam, cefuroxime, cefotaxime, ceftazidime, imipenem, gentamicin, nitrofurantoin, and fosfomycin, and the lowest were to amoxicillin-clavulanic acid and cotrimoxazole. Among all bacteria isolated, we highlight the overall high activity of piperacillin-tazobactam, imipenem, nitrofurantoin, and fosfomycin against both community and hospital isolates and the reduced activity of amoxicillin-clavulanic acid, cephalosporins, gentamicin, and cotrimoxazole. There was no significant change in the total activity of any of the studied antibiotics over the 4-year study period. Conclusion. Empiric treatment with amoxicillin-clavulanic acid, cotrimoxazole, cephalosporins, and gentamicin may be inadequate due to their limited activity against uropathogens in our setting.

[Hospitalization rate in relation to severe complications of transrectal prostate biopsy: About 2715 patients biopsied]

MAIN OBJECTIVE

To identify hospitalizations directly related to a complication occurring within 30 days following a transrectal prostate biopsy (PBP).

SECONDARY OBJECTIVES

Overall hospitalization rates, mortality rates, potential predisposing factors for complications.

PATIENTS AND METHODS

Single-center study including all patients who underwent PBP between January 2005 and January 2012. Any hospitalization occurring within 30 days of the PBP for urgent motive was considered potentially attributable to biopsy. We identified the reason for hospitalization with direct complications (urinary infection or fever, rectal bleeding, bladder caillotage, retention) and indirect (underlying comorbidities decompensation) of the biopsy. The contributing factors were anticoagulant or antiplatelet treatment well as waning immunity factors (corticosteroid therapy, HIV, chemotherapy or immunodulateur).

RESULTS

Among 2715 men who underwent PBP, there were 120 (4.4%) hospitalizations including 28 (1.03%) caused by the biopsy. Twenty-five (0.92%) were related to a direct complication of biopsy: 14 (56%) for urinary tract infection or fever including 1 hospitalization in intensive care, 5 (20%) for rectal bleeding which required several transfusions 1, 10 (40%) urinary retention and 3 (0.11%) for an indirect complication (2 coronary syndromes and 1 respiratory failure). Several direct complications were associated in 3 cases. Only two hospitalizations associated with rectal bleeding were taking an antiplatelet or anticoagulant. There was no association between hospitalization for urinary tract infections and a decreased immune status. The first death observed in our study occurred at D31 of pulmonary embolism (advanced metastatic patient with bladder cancer). Twenty (60.6%) patients urgently hospitalized did not have prostate cancer.

CONCLUSIONS

Within this large sample of patients the overall rate of hospitalization due to the realization of a PBP was 1%. It has not been found predictive of complications leading to hospitalization.

LEVEL OF EVIDENCE

4.

Whole-Genome Comparative Analysis of Two Carbapenem-Resistant ST-258 Klebsiella pneumoniae Strains Isolated during a North-Eastern Ohio Outbreak: Differences within the High Heterogeneity Zones

Klebsiella pneumoniae has become one of the most dangerous causative agents of hospital infections due to the acquisition of resistance to carbapenems, one of the last resort families of antibiotics. Resistance is usually mediated by carbapenemases coded for by different classes of genes. A prolonged outbreak of carbapenem-resistant K. pneumoniae infections has been recently described in northeastern Ohio. Most strains isolated from patients during this outbreak belong to MLST sequence type 258 (ST258). To understand more about this outbreak two isolates (strains 140 and 677), one of them responsible for a fatal infection, were selected for genome comparison analyses. Whole genome map and sequence comparisons demonstrated that both strains are highly related showing 99% average nucleotide identity. However, the genomes differ at the so-called high heterogeneity zone (HHZ) and other minor regions. This study identifies the potential value of the HHZ as a potential marker for K. pneumoniae clinical and epidemiological studies.

Incidence of antibiotics resistance among uropathogens in Omani children presenting with a single episode of urinary tract infection

Urinary tract infection (UTI) is one of the most common community-acquired infections. Different organisms can be the cause of UTI in children, with resistance to antibiotics becoming a significant problem in the choice of treatment. Worldwide studies have documented the prevalence of uropathogens in different countries. However, there is no previous study documenting the incidence of different uropathogens in Oman. We aim to report the most common uropathogens and their antibiotic sensitivity patterns in children presenting with documented, single episode UTI at a tertiary hospital in Oman. A retrospective analysis of all Omani children below 14 years who presented with a case of first documented UTI to SQUH between September 2008 and August 2012 was conducted. Data were obtained from the patients' electronic records in the hospital information system. Data were then analyzed using SSPS (Statistical Package for Social Sciences program, Version 20, IBM, Chicago, IL, USA). In the retrospective review of all urine cultures, 438 positive urine cultures were identified. Out of those, 208 (47.5%) belonged to children with their first episode of UTI. Thirty-three patients were excluded and 75 patients were included in the final analysis. Escherichia coli was the most frequently encountered uropathogen in our cohort (69%), followed by Klebsiella pneumoniae infection (17%). Nearly half (46.6%) of these two common organism were resistant to Cotrimoxazole, while 31% of them were resistant to Augmentin. Twenty-four percent of the E. coli and K. pneumoniae strains were resistant to Cefuroxime, and only 10% were resistant to nitrofurantoin. Both Augmentin and Cotrimoxazole should not be the first line antibiotics to treat UTI.

Evolution of the resistance to antibiotics of bacteria involved in urinary tract infections: a 7-year surveillance study

BACKGROUND

We conducted a retrospective analysis on the identification and antibiogram of all bacteria isolated from urine samples with microbiological confirmation of urinary tract infection (UTI) in a Spanish reference hospital over a 7-year period.

METHODS

A retrospective analysis was performed of the identification and antibiogram data.

RESULTS

A total of 31,758 uropathogens were isolated. Escherichia coli accounted for the majority (55.2%) of these, followed by Enterococcus faecalis (18.0%) and Klebsiella spp (10.3%). The highest E coli susceptibility rates were to imipenem (93.0%-99.8%), amikacin (97.3%-99.5%), nitrofurantoin (96.7%-98.9%), and fosfomycin (95.3%-100%), and the lowest were to cefuroxime (67.8%-86.4%), ciprofloxacin (61.2%-69.8%), and co-trimoxazole (55.0%-65.5%). We highlight the overall high activity of imipenem, piperacillin-tazobactam, nitrofurantoin, and fosfomycin on isolates versus the low activity of fluoroquinolones, co-trimoxazole, or cephalosporins. The activity of amoxicillin-clavulanic acid and fosfomycin decreased significantly over the 7-year study period.

CONCLUSIONS

Imipenem and piperacillin-tazobactam appear to be good options for the empiric treatment of UTI acquired in hospital or requiring hospitalization, whereas nitrofurantoin and fosfomycin can be first-choice antibiotics for the treatment of uncomplicated community-acquired cystitis. However, surveillance studies are required to detect resistance to these antibiotics, given that an increase in uropathogen resistance rates may contraindicate its future use in empiric UTI therapy.

Plasmid-Mediated Antibiotic Resistance and Virulence in Gram-negatives: the Klebsiella pneumoniae Paradigm

Plasmids harbor genes coding for specific functions including virulence factors and antibiotic resistance that permit bacteria to survive the hostile environment found in the host and resist treatment. Together with other genetic elements such as integrons and transposons, and using a variety of mechanisms, plasmids participate in the dissemination of these traits resulting in the virtual elimination of barriers among different kinds of bacteria. In this article we review the current information about physiology and role in virulence and antibiotic resistance of plasmids from the gram-negative opportunistic pathogen Klebsiella pneumoniae. This bacterium has acquired multidrug resistance and is the causative agent of serious communityand hospital-acquired infections. It is also included in the recently defined ESKAPE group of bacteria that cause most of US hospital infections.

Treatment option for sepsis in children in the era of antibiotic resistance

Sepsis caused by multidrug-resistant microorganisms is one of the most serious infectious diseases of childhood and poses significant challenges for pediatricians involved in management of critically ill children. This review discusses the use of pharmacokinetic/dynamic principles (i.e., prolonged infusion of β-lactams and vancomycin, once-daily administration of aminoglycosides and rationale of therapeutic drug monitoring) when prescribing antibiotics to critically ill patients. The potential of 'old' agents (i.e., colistin, fosfomycin) and newly approved antibiotics is critically reviewed. The pros and cons of combination antibacterial therapy are discussed and finally suggestions for the treatment of sepsis caused by multidrug-resistant organisms are provided.

Distribution and antimicrobial susceptibility pattern of bacterial pathogens causing urinary tract infection in urban community of meerut city, India

Urinary tract infection is one of the common infections in the Indian community. Distribution and susceptibility of UTI-causing pathogens change according to time and place. This study was conducted to determine the distribution and antimicrobial susceptibility of uropathogens in the Indian community as well as to determine the effect of gender and age on the etiology of bacterial uropathogens. Clean catch midstream urine samples were collected from 288 patients of the age ranging from 15 to ≥48 years. Antimicrobial susceptibility was performed on all isolated bacteria by Kirby Bauer's disc diffusion method. The multiple antibiotic resistance (MAR) index of each antibiotic was calculated. The UTI prevalence was 53.82% in patients; however, the prevalence was significantly higher in females than in males (females: 73.57%; males: 35.14%; P = 0.000). Females within the age group of 26-36 years and elderly males of ≥48 years showed higher prevalence of UTI. Gram negative bacteria (90.32%) were found in high prevalence than Gram positive (9.68%). Escherichia coli (42.58%) was the most prevalent gram negative isolate. Nitrofurantoin (78.71%) was found the most resistant drug among all uropathogens. Tested carbapenems were found the most susceptible drug against isolated uropathogens which showed 92.26% and 84.52% susceptibility, respectively.

Analysis of the spectrum and antibiotic resistance of uropathogens in vitro: results based on a retrospective study from a tertiary hospital

BACKGROUND

Antibiotic resistance of uropathogens in urinary tract infections (UTIs) is increasing worldwide. This study aimed to compare the spectrum and antimicrobial resistance of uropathogens in community-acquired UTIs (CAUTIs) and nosocomial-acquired UTIs (NAUTIs) at a tertiary hospital in China.

METHODS

Retrospective analysis of uropathogens from UTI patients was performed at Zhong Da Hospital.

RESULTS

A total of 1129 strains was isolated from 653 community-acquired and 476 nosocomial-acquired infections. Escherichia coli was the most common uropathogen, accounting for 55.9% of the CAUTIs and 27.1% of the NAUTIs. Among the CAUTIs, Escherichia coli was followed in prevalence by Enterococcus spp (12.9%) and Proteus mirabilis (3.7%). Among the NAUTIs, Escherichia coli was followed by Enterococcus spp (15.3%) and Klebsiella pneumoniae (6.9%). The proportion of fungi in the NAUTIs (23.7%) was higher than that in the CAUTIs (3.1%) (P < .05). Extended-spectrum β-lactamase-producing strains of E coli accounted for 70.6% of the NAUTIs and 47.3% of the CAUTIs. Carbapenems, amikacin, and nitrofurantoin were active agents against E coli. The resistance rates of E coli to cephalosporins, ampicillin, ampicillin/sulbactam, quinolones, and gentamicin were higher in the NAUTIs than in the CAUTIs (P < .05).

CONCLUSION

The distribution of species was different between CAUTIs and NAUTIs. Higher antibiotic resistance rates were observed in the NAUTIs than in the CAUTIs.

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

Our objective was to evaluate the antimicrobial susceptibility of Enterobacteriaceae causing urinary tract infections (UTIs) in adults in Africa. The PubMed database was systematically searched to identify relevant studies published after 2000. Google, World Health Organization, and African Field Epidemiology networks were also searched. Twenty-eight studies, accounting for 381,899 urine isolates from 14 African countries, met the inclusion criteria. Escherichia coli, Klebsiella spp., and Proteus spp. were the most commonly encountered uropathogens. Cefotaxime, imipenem, fosfomycin, and ciprofloxacin were the antibiotics with the highest activity against E. coli isolates from outpatients, with susceptibility being 92 to 99, 100, 100, and 68 to 91%, respectively. The susceptibility among Klebsiella spp. isolates from outpatients varied from 80 to 100% for amikacin and from 53 to 100% for ciprofloxacin, while susceptibility was 74 to 78, 97, and 77% for ciprofloxacin, amikacin, and fosfomycin, respectively, among Klebsiella species isolates from inpatients or patients with hospital-acquired UTIs. With regard to Proteus spp., the highest activity was observed among fluoroquinolones; 71 to 100% of the P. mirabilis isolates were susceptible to ciprofloxacin in four studies, and 74 to 100% of the P. vulgaris isolates were susceptible to ofloxacin in two studies. The currently available evidence suggests that the antimicrobial susceptibility patterns of Enterobacteriaceae uropathogens in African countries were similar to those in countries of southeast Europe. Further original studies are warranted from African countries for which there is limited published data.

Genome Sequences of Two Klebsiella pneumoniae Isolates from Different Geographical Regions, Argentina (Strain JHCK1) and the United States (Strain VA360)

We report the sequences of two Klebsiella pneumoniae clinical isolates, strains JHCK1 and VA360, from a newborn with meningitis in Buenos Aires, Argentina, and from a tertiary care medical center in Cleveland, OH, respectively. Both isolates contain one chromosome and at least five plasmids; isolate VA360 contains the Klebsiella pneumoniae carbapenemase (KPC) gene.

Urinary tract infection among symptomatic outpatients visiting a tertiary hospital based in midwestern Nigeria

Microbial pathogens implicated in urinary tract infection and their antibiotic susceptibility patterns as prevalent in UTI symptomatic outpatients resident in Benin City, Nigeria was the focus of this study. One hundred (100) midstream urine samples were collected into sterile plastic universal bottles from outpatients who visited the University of Benin Teaching Hospital, Nigeria and who were tentatively diagnosed as manifesting symptoms of UTI. Patients were referred to the Medical Microbiology department by the consulting doctors. Significant bacterial counts and neutrophil (pus cells) counts were carried out on samples by standard methods. Positive samples for both counts were inoculated aseptically on sterile MacConkey agar, Cystine Lactose Electrolyte Deficient (CLED) agar and Sabouraud Dextrose agar plates and incubated appropriately. Microbial isolates were identified and antibiotic sensitivity testing was carried out on isolates by standard methods. Thirty nine (39.0%) and 61 (61.0%) samples recorded significant microbial growth and no growth respectively. Gram negative bacilli constituted 86.1% (of which enterobacteriaceae made up 49.9%) while gram positive cocci made up 13.9%. Strains of uropathogens isolated were Alcaligenes spp (19.4%), Klebsiella aerogenes (16.7%), Escherichia coli (13.9%), Staphylococcus aureus (13.9%), Candida albicans (11.1%), Proteus mirabilis (8.3%), Pseudomonas aeruginosa (5.5%), Enterobacter spp (5.5%) and Providencia spp (5.5%). Occurrence of UTI in male and female patients were 58.3% and 41.7% respectively of which UTI occurred highest in the 25-46, 15-54 and 27-54 age groups in that decreasing order. Alcaligenes spp occurred most in very old female patients. Candida albicans (the only fungal uropathogen) occurred in an 8day old male patient. Other isolates occurred in much older patients. A significantly high microscopic neutrophil count or pyuria was recorded from deposits of UTI positive patients (i.e. < 5/HPF). Eighteen (representing 50.5%) and 15 (47.8%) of total microbial strains isolated were sensitive to nitrofurantoin and ceftriaxone respectively. Antibiotic susceptibility profile also showed 13(41.6%), 13(41.6%), 13(41.6%) for ciprofloxacin, cefuroxime and ofloxacin respectively suggesting moderate sensitivity of the fluoroquinolones and second/third generation cephalosporins. Gentamicin, ampicillin and augmentin recorded over 70.0% resistance level each. A total of nineteen bacterial strains made of E.coli, Enterobacter spp, Proteus mirabilis, Providencia spp, Staph. aureus and Pseudomonas aeruginosa were multi drug resistant as they resisted 3, 3, 4, 4, 5 and 8 antibiotics respectively.

Comparison of antibiotic resistance patterns in collections of Escherichia coli and Proteus mirabilis uropathogenic strains

Escherichia coli and Proteus mirabilis are important urinary tract pathogens. The constant increase in the antibiotic resistance of clinical bacterial strains has become an important clinical problem. The aim of this study was to compare the antibiotic resistance of 141 clinical (Sweden and Poland) and 42 laboratory (Czech Republic) P.mirabilis strains and 129 clinical (Poland) uropathogenic E. coli strains. The proportion of unique versus diverse patterns in Swedish clinical and laboratory P. mirabilis strain collections was comparable. Notably, a similar proportion of unique versus diverse patterns was observed in Polish clinical P. mirabilis and E. coli strain collections. Mathematical models of the antibiotic resistance of E. coli and P. mirabilis strains based on Kohonen networks and association analysis are presented. In contrast to the three clinical strain collections, which revealed complex associations with the antibiotics tested, laboratory P. mirabilis strains provided simple antibiotic association diagrams. The monitoring of antibiotic resistance patterns of clinical E. coli and P. mirabilis strains plays an important role in the treatment procedures for urinary tract infections and is important in the context of the spreading drug resistance in uropathogenic strain populations. The adaptability and flexibility of the genomes of E. coli and P.mirabilis strains are discussed.

Emergency Department vancomycin use: dosing practices and associated outcomes

BACKGROUND

Emergency Department (ED) dosing of vancomycin and its effect on outcomes has not been examined.

STUDY OBJECTIVE

To describe current vancomycin dosing practices for ED patients, focusing on patient factors associated with administration, dosing accuracy based on patient body weight, and clinical outcomes.

METHODS

Single-center, retrospective cohort study of vancomycin administered in the ED over 18 months in an academic, tertiary care ED. Data were collected on 4656 patients. Data were analyzed using a generalized estimating equations model to account for multiple doses being administered to the same patient.

RESULTS

The ED dose was continued, unchanged, in 2560 admitted patients (83.8%). The correct dose was given 980 times (22.1%), 3143 doses (70.7%) were underdosed, and 318 were overdosed (7.2%). Increasing weight was associated with underdosing (adjusted odds ratio 1.52 per 10 kg body weight, p < 0.001). Patients who received doses of vancomycin > 20 mg/kg had longer hospital length of stay (p = 0.005); were more likely to spend ≥ 3 days in the hospital (odds ratio [OR] 1.49; 95% confidence interval [CI] 1.12-1.98, p = 0.006); and more likely to die (OR 1.88; 95% CI 1.22-2.90, p = 0.004).

CONCLUSION

In this largest study to date examining ED vancomycin dosing, vancomycin was commonly given. Dosing outside the recommended range was frequent, and especially prevalent in patients with a higher body weight. The ED dose of vancomycin was frequently continued as an inpatient, regardless of dosing accuracy. There is significant room for improvement in dosing accuracy and indication. Vancomycin dosing in the ED may also affect clinical outcomes.

Changing antibiotic susceptibilities of community-acquired uropathogens in Greece, 2005-2010

PURPOSE

The purpose of this study was to determine the distribution and changes in the antibiotic susceptibilities of uropathogens isolated from adults with community-acquired urinary tract infections (CA-UTIs) in Crete, Greece, over a 6-year period.

METHODS

This study was performed with isolates from outpatients with UTIs, collected between 2005 and 2010. Isolates were identified by standard methods and antimicrobial susceptibility testing was performed using the disk diffusion method and the VITEK2 is an automated system used for identification and antimicrobial susceptibility testing of microorganisms (BioMerieux). To identify changes in susceptibility patterns, we compared results of the period 2005-2007 to those of the period 2008-2010. We also compared the antibiotic susceptibilities of isolates between males and females.

RESULTS

A total of 4011 community-acquired uropathogens were isolated during the period of 2005-2010. Escherichia coli was the most common organism and responsible for 68.9% of CA-UTIs, followed by Proteus mirabilis (6.8%), Klebsiella pneumoniae (6.4%) and enterococci (6%). A significant increase in resistance of E coli isolates was noted for β-lactams, monobactams, aminoglycosides, quinolones, and cotrimoxazole. The reverse trend was evident for nitrofurantoin. Higher resistance rates of community-acquired E coli and non-E coli Enterobacteriaceae were noted in males for ampicillin, amoxicillin plus clavulanic acid, cephalosporins, aminoglycosides, and quinolones. No significant sex differences were noted in the antibiotic susceptibility patterns of enterococci.

CONCLUSION

There is a concerning trend for increasing resistance among E coli and non-E coli Enterobacteriaceae responsible for CA-UTIs in Crete in recent years likely due to the inappropriate use of broad spectrum antibiotics, as a substitute for precise diagnostics and/or to increase the chances of therapeutic success.

Gender and age-dependent etiology of community-acquired urinary tract infections

Urinary tract infections (UTIs) are among the most frequent community-acquired infections worldwide. Escherichia coli is the most common UTI pathogen although underlying host factors such as patients' age and gender may influence prevalence of causative agents. In this study, 61 273 consecutive urine samples received over a 22-month period from outpatients clinics of an urban area of north Italy underwent microbiological culture with subsequent bacterial identification and antimicrobial susceptibility testing of positive samples. A total of 13 820 uropathogens were isolated and their prevalence analyzed according to patient's gender and age group. Overall Escherichia coli accounted for 67.6% of all isolates, followed by Klebsiella pneumoniae (8.8%), Enterococcus faecalis (6.3%), Proteus mirabilis (5.2%), and Pseudomonas aeruginosa (2.5%). Data stratification according to both age and gender showed E. coli isolation rates to be lower in both males aged ≥60 years (52.2%), E. faecalis and P. aeruginosa being more prevalent in this group (11.6% and 7.8%, resp.), as well as in those aged ≤14 years (51.3%) in whom P. mirabilis prevalence was found to be as high as 21.2%. Streptococcus agalactiae overall prevalence was found to be 2.3% although it was shown to occur most frequently in women aged between 15 and 59 years (4.1%). Susceptibility of E. coli to oral antimicrobial agents was demonstrated to be as follows: fosfomycin (72.9%), trimethoprim/sulfamethoxazole (72.9%), ciprofloxacin (76.8%), ampicillin (48.0%), and amoxicillin/clavulanate (77.5%). In conclusion, both patients' age and gender are significant factors in determining UTIs etiology; they can increase accuracy in defining the causative uropathogen as well as providing useful guidance to empiric treatment.

A reappraisal of current dosing strategies for intravenous fosfomycin in children and neonates

The rising incidence of multi-drug resistant bacterial pathogens has renewed interest in the long-known antibacterial fosfomycin. Not least because of its low toxicological potential, there is good clinical experience with intravenous fosfomycin for various Gram-positive and Gram-negative infections in the treatment of children and neonates. However, the current dosing recommendations for intravenous fosfomycin vary widely in paediatric patients. In the present review, we summarized available plasma pharmacokinetic data derived from neonates or children following intravenous administration of fosfomycin. Subsequently, we used this information for recalculation of different dosing strategies and simulated a variety of clinically applied dosing regimens. The percentage of time above the minimal inhibitory concentration (T>MIC) was calculated for each dosing strategy, as this pharmacokinetic-pharmacodynamic parameter was shown to be most predictive of antimicrobial and clinical success of fosfomycin treatment. Our data corroborate the current practice of selecting the dosage of intravenous fosfomycin primarily on the basis of bodyweight and age in paediatric patients. As with other 'time-dependent' antibacterials, a dosing interval of 6-8 hours should be preferred over 12 hours except for immature neonates. Given a T>MIC target of 40-70%, currently recommended dosing strategies appear to be insufficient in children aged 1-12 years, if pathogens with MICs of ≥32 mg/L are suspected and subjects are presenting with normal renal function. Likewise, the lowest recommended daily dose for neonates and infants (aged up to 12 months) of 100 mg/kg bodyweight of fosfomycin should be considered only for pre-term neonates with a postmenstrual age below 40 weeks.

Data mining derived treatment algorithms from the electronic medical record improve theoretical empirical therapy for outpatient urinary tract infections

PURPOSE

We determined whether data mining derived algorithms from electronic databases can improve empirical antimicrobial therapy in outpatients with a urinary tract infection.

MATERIALS AND METHODS

The electronic medical records from 3,308 visits associated with a positive urine culture at Northwestern's outpatient Urology and Internal Medicine clinics and Emergency Department from 2005 to 2009 were interrogated. Bacterial species and susceptibility rates for trimethoprim-sulfamethoxazole, ciprofloxacin and nitrofurantoin were compared. Using data mining techniques we created algorithms for empirical therapy of urinary tract infections and compared the theoretical outcomes from data mining derived therapy to those from conventional therapy.

RESULTS

Patients were significantly older in the Department of Urology vs Internal Medicine vs Emergency Department, and more patients in the Department of Urology were male. During the 5-year period the susceptibility rates for ciprofloxacin in the Department of Urology and trimethoprim-sulfamethoxazole in Internal Medicine decreased significantly. In the Department of Urology the susceptibility rate for nitrofurantoin was greater than for ciprofloxacin, which was greater than for trimethoprim-sulfamethoxazole. In all departments, bacteria were more resistant to trimethoprim-sulfamethoxazole than to ciprofloxacin or nitrofurantoin. All drugs were more effective in the Emergency Department and Internal Medicine than the Department of Urology. Prior resistance patterns were the strongest predictor of current susceptibility profiles. In the Department of Urology the algorithms for patients with or without prior cultures theoretically outperformed conventional therapy in men (13.2%) and women (10.1%).

CONCLUSIONS

Antimicrobial resistance patterns in outpatient urinary tract infections are time dependent, and drug and site specific. Data mining directed therapy significantly improved theoretical outcomes compared to conventional therapy for Department of Urology outpatients and for female patients in the Emergency Department.

Ertapenem for the treatment of urinary tract infections caused by extended-spectrum β-lactamase-producing bacteria in children

BACKGROUND

Urinary tract infections (UTIs) are a problem frequently encountered by paediatric healthcare providers. Recent data suggest that extended-spectrum β-lactamase (ESBL)-producing bacteria are an emerging cause of UTIs in non-hospitalized patients. We report our experience of ertapenem use in 50 patients with complicated UTIs, mainly pyelonephritis, caused by ESBL-producing organisms.

METHODS

Fifty patients aged <16 y who had a complicated UTI caused by ESBL-producing organisms and who were treated with ertapenem at our hospital from 1 January 2009 to 31 December 2009, were included in the study.

RESULTS

There were 20 (40%) males and 30 (60%) females with a mean ± standard deviation age of 38.6 ± 36.9 months (range 6-156 months). Twenty-eight patients had no urological abnormality. In 40 patients ertapenem was initiated after results of microbiological cultures became available. Ertapenem was initiated empirically for 10 patients known to be colonized with ESBL-producing bacteria. Urine cultures were negative at 3.3 ± 0.7 days (range 2-5 days) after starting ertapenem treatment. The mean duration of ertapenem treatment was 7.8 ± 1.2 days (range 7-14 days). No laboratory or clinical side effects were observed.

CONCLUSIONS

Ertapenem is promising for the culture-guided treatment of ESBL-producing Gram-negative complicated UTIs. Well-designed prospective studies are needed to define the role of ertapenem in treating complicated paediatric UTIs, especially upper UTIs.

Contribution of mutations in DNA gyrase and topoisomerase IV genes to ciprofloxacin resistance in Escherichia coli clinical isolates

DNA gyrase (GyrA and GyrB) and topoisomerase IV (ParC and ParE) are the two essential type II topoisomerases in Escherichia coli. These enzymes act via inhibition of DNA replication. Mutations in the quinolone resistance-determining region (QRDR) of the gyrA, gyrB, parC and parE genes from clinical isolates of E. coli were determined by DNA sequencing of 54 ciprofloxacin-resistant clinical isolates from a hospital in Delhi, India. The majority of the E. coli isolates were shown to carry mutations in gyrA, parC and parE. Ciprofloxacin resistance due to accumulation of such a high number of mutations in the QRDR regions of gyrA at positions Ser83 and Asp87 and parC at position Ser80 as well as outside of the QRDR region of parE at Ser458 and Glu460 confers high-level resistance of ciprofloxacin in clinical isolates. The high frequency of occurrence of mutations in the parE gene (44.4% strains) is alarming, as topoisomerase IV is a secondary target of quinolones.

High prevalence of bla(CTX-M) extended spectrum beta-lactamase genes in Klebsiella pneumoniae isolates from a tertiary care hospital: first report of bla(SHV-12), bla(SHV-31), bla(SHV-38), and bla(CTX-M-15) in Brazil

The aim of this study was to investigate the presence and prevalence of bla(TEM), bla(SHV), and bla(CTX-M) and bla(GES)-like genes, responsible for extended spectrum beta-lactamases (ESBLs) production in clinical isolates of Klebsiella pneumoniae collected from a Brazilian tertiary care hospital. Sixty-five ESBL producing K. pneumoniae isolates, collected between 2005 and 2007, were screened by polymerase chain reaction (PCR). Identification of bla genes was achieved by sequencing. Genotyping of ESBL producing K. pneumoniae was performed by the enterobacterial repetitive intergenic consensus-PCR with cluster analysis by the Dice coefficient. The presence of genes encoding ESBLs was confirmed in 59/65 (90.8%) isolates, comprising 20 bla(CTX-M-2), 14 bla(CTX-M-59), 12 bla(CTX-M-15), 9 bla(SHV-12), 1 bla(SHV-2), 1 bla(SHV-2a), 1 bla(SHV-5), and 1 bla(SHV-31) genes. The ESBL genes bla(SHV-12), bla(SHV-31), and bla(CTX-M-15), and the chromosome-encoded SHV-type beta-lactamase capable of hydrolyzing imipenem were detected in Brazil for the first time. The analysis of the enterobacterial repetitive intergenic consensus-PCR band patterns revealed a high rate of multiclonal bla(CTX-M) carrying K. pneumoniae isolates (70.8%), suggesting that dissemination of encoding plasmids is likely to be the major cause of the high prevalence of these genes among the K. pneumoniae isolates considered in this study.

Efficacy and safety of ciprofloxacin XR 1000 mg once daily versus ciprofloxacin 500 mg twice daily in the treatment of complicated urinary tract infections

The aim of this trial was to compare the efficacy and safety of extended-release ciprofloxacin (CIPRO XR) versus the immediate-release formulation (CIPRO IR) in the treatment of complicated urinary tract infections (UTIs). 212 patients were randomized to CIPRO XR 1,000 mg tablet once daily or CIPROXIN IR 500 mg tablet twice daily. Treatment efficacy was evaluated by bacteriological outcome. Safety was measured by recording adverse events. The rate of bacteriological eradication was 83% in the CIPRO XR group and 75% in the CIPRO IR. the overall incidence of adverse events reported was higher in the CIPRO IR group. The authors conclude that CIPRO XR is a safe and effective treatment for complicated UTIs. Although the limited data available do not consent to support a statistically superior efficacy or safety compared to CIPRO IR, a trend in favor of CIPRO XR is clearly evident in all efficacy and safety variables. CIPRO XR is associated with reduced frequencies of drug-related adverse events compared to CIPRO IR.

Risks factors for infections with extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae at a tertiary care university hospital in Switzerland

BACKGROUND

There are considerable geographical differences in the occurrence of extended-spectrum beta-lactamase(ESBL)-producing bacteria, both in the community and in the hospital setting. Our aim was to assess risk factors for blood stream, urinary tract, and vascular catheter-associated infections with ESBL-producing Escherichia coli and Klebsiella pneumoniae at a tertiary care hospital in a low-prevalence country.

METHODS

We performed a case-control study comparing 58 patients with infections due to ESBL-producing E. coli orK. pneumoniae vs 116 controls with infections due to non-ESBL producing organisms at the University Hospital Zurich, Switzerland, between 1 July 2005 and 30 June 2007.

RESULTS

Cases included 15 outpatients and 43 inpatients. Multivariable analyses found three risk factors for ESBL-producing isolates: begin of symptoms or recent antibiotic pre-treatment in a foreign country (odds ratio [OR] 27.01,95% confidence interval [CI] 2.38-1,733.28], p = 0.042),antibiotic therapy within the year preceding the isolation of the ESBL-producing strain (OR 2.88, 95% CI 1.13-8.49,p = 0.025), and mechanical ventilation (OR 10.56, 95% CI 1.06-579.10, p = 0.042).

CONCLUSIONS

The major risk factors for infections due to ESBL-producing bacteria were travel in high-prevalence countries, prior antibiotic use, and mechanical ventilation during a stay in the intensive care unit. Community-acquired infections were documented in 17% of the patients.An early identification of risk factors is crucial to providing the patients an optimal empiric antibiotic therapy and to keep the use of carbapenems to a minimum.

In vitro susceptibility of quinolone-resistant Enterobacteriaceae uropathogens to fosfomycin trometamol, in Dakar, Senegal

We conducted a study in order to confirm the eligibility of fosfomycin trometamol as an alternative treatment to quinolones for urinary tract infections. Among 102 quinolone-resistant Enterobacteriaceae strains, resistance rates to first line-prescribed antibiotics were above 77%. The resistance rate to fosfomycin was 2%.

Rapid and simple determination of ciprofloxacin resistance in clinical strains of Escherichia coli

We recently reported a simple new in situ diffusion assay, developed as a kit, to visualize DNA fragmentation in single bacterial cells. Use of this assay in a collection of 95 genetically unrelated Escherichia coli clinical strains resulted in correct identification of all of the isolates as resistant or susceptible to ciprofloxacin, consistent with the MIC results. This relevant information is obtained in 80 min.

Acute pyelonephritis: clinical characteristics and the role of the surgical treatment

The epidemiology of acute pyelonephritis (APN) has changed with time. Therefore we investigated the current clinical characteristics of APN and the significance of proper surgical management for treatment of 1,026 APN patients in South Korea for the past 5 yr. The male-to-female ratio was about 1:8. The peak ages of female patients were 20s (21.3%) and over 60s (23.7%), while that of male was over 60s (38.1%). The occurrence of sepsis was 10.1%. Complicated APN patients were 35.4%. Ninety-four patients (9.2%) needed urological procedures. The duration of the flank pain and of the costovertebral angle tenderness in complicated APN patients was statistically significantly longer than that with simple APN patients (4.3 vs. 3.4 days, 4.4 vs. 4.0 days). If flank pain and costovertebral angle tenderness sustain over 4 days, proper radiologic studies should be performed immediately with the consideration of surgical procedure. Also the resistance to antibiotics was increasing. As the sensitivities to ampicillin (27.2%) and trimethoprim/sulfamethoxazole (44.7%) of Escherichia coli and Klebsiella pneumoniae were very low, it is necessary to take the careful choice of antibiotics into consideration.

Laser interferometric and cultivation methods for measurement of colistin/ampicilin and saponin interactions with smooth and rough of Proteus mirabilis lipopolysaccharides and cells

Laser interferometry is commonly used in permeability studies of soluble substances. In this study a modification that allowed testing partially insoluble mixtures is presented. The modification relies on the measurement of diffusion from 1% agarose gel. As a model for this study, two Proteus mirabilis strains were used that differ in polysaccharide content: smooth P. mirabilis S1959 strain and its Re-type mutant, strain R45. By laser interferometry and precipitation it is shown that R45 lipopolysaccharide is more effective in binding colistin. It has been shown with the laser interferometric method that saponins, which are detergent-like substances of plant origin, partially enhance the interaction of colistin with the S and Re types of P. mirabilis. These results were confirmed with whole cell Proteus studies. The saponin partially inhibited the growth of the S and Re P. mirabilis strains at doses of 31-500 microg/ml. A sub-inhibitory dose--15 microg/ml of saponins alone do not reduced the numbers of P. mirabilis S1959 and R45 cells. However, the presence of colistin or amipicillin and 15 microg/ml of saponins reduced the amount of P. mirabilis S1959 and R45 cells. The saponins enhanced sensitivities of S and R P. mirabilis cells towards colistin and amipicillin. One may proposed that saponins binds to lipid A part of LPS may resulted on an increase in bacterial cell wall outer-membrane permeabilities and by that facilitated antibiotics penetration into the bacterial cells. In conclusion, the laser interferometric method is a useful tool for studies of lipopolysaccharide-antibiotic interactions even if the tested substances are not fully soluble in water.

Cross-resistance and associated resistance in Escherichia coli isolates from nosocomial urinary tract infections between 2004–2006 in a Turkish Hospital

In this study, antimicrobial resistance profiles were determined for 748 isolates of Escherichia coli from patients with acute nosocomial urinary tract infections (UTIs) at a Turkish Training Hospital. Thirteen antibiotics were included. Resistance to ampicillin alone (45.1%) and ciprofloxacin alone (20.6%) were the most commonly identified ‘single resistances’. Multiple resistance was found in 49.7% of the strains. The most common multiple antibiotic resistance profiles included ampicillin-sulbactam/amoxycilline-clavulonate (4.0%) and ampicillin-sulbactam/trimethoprim-sulfamethoxazole/amoxycilline-clavulonate (2.8%). From 2004 to 2006, ampicillin, trimethoprim-sulfamethoxazole and ciprofloxacin resistant strains increased to 76% from 57%, 53% from 43% and 55% from 41%, respectively. The percentage of extended-spectrum β-lactamase (ESBL) producing strains was 7.8% and imipenem resistance was seen in 5.2% of ESBL positive strains. We conclude that clinically important E.coli strains have now emerged with broader multidrug resistance. Periodical evaluation of laboratory results and clinical surveillance are crucially important for optimal antibiotic management of UTIs and infection control policies.

[Etiological profile of urinary tract infections and antimicrobial susceptibility of urinary pathogens]

A review on the etiological profile of urinary tract infections in childhood and the sensitivity pattern of urinary pathogens in Spain is presented. Escherichia coli continues to be the main etiological agent of urinary tract infection in childhood. Consequently, its sensitivity pattern will usually determine the choice of empirical therapy. The predominance of E. coli is reduced in certain circumstances, in which the presence of other microorganisms is increased. However, the clinical information available at diagnosis does not allow accurate identification of the etiology; only staining and microscopic urine examination can help in treatment selection. In Spain, E. coli presents a high percentage of resistance to ampicillin and cotrimoxazole, whereas second- and third-generation cephalosporins, fosfomycin, aminoglycosides and amoxicillin-clavulanate maintain high sensitivity. In some areas, amoxicillin-clavulanate and first-generation cephalosporins show high levels of resistance, which can limit their empirical use.

Clinical and molecular epidemiology of community-onset, extended-spectrum beta-lactamase-producing Escherichia coli infections in Thailand: a case-case-control study

BACKGROUND

Extended-spectrum beta-lactamase (ESBL)-producing organisms, first identified in Germany in 1983, are now widely recognized as clinically relevant causes of infections in community.

METHODS

Our objective was to evaluate the clinical and molecular epidemiology of community-onset, extended-spectrum beta-lactamase (CO-ESBL)-producing Escherichia coli infections. We used a case-case-control study undertaken in a 450-bed, tertiary care hospital. Patients included case group (CG) I, which had confirmed CO-ESBL-producing E coli infections (n=46). Case group (CG) II (n=46) included patients with CO-non-ESBL-producing E coli infections. Controls (n=138) were patients without infections.

RESULTS

By multivariate analysis, diabetes (95% confidence interval [CI]: 1.9-13.2, P< .001), prior ESBL E coli colonization (<90 days) (95% CI: 1.2-67.8, P< .001), recent receipt of antibiotics (<90 days) (95% CI: 4.2-44.2, P= .004), and previous exposure to third-generation cephalosporins (95% CI: 2.2-16.4, P= .001) and fluoroquinolones (95% CI: 1.4-18.3; P= .003) were associated risks among CG I. Diabetes (95% CI: 1.6-15.4, P= .005), stroke (95% CI: 1.5-17.1, P= .001), and diarrhea (95% CI: 3.8-65.8, P= .001) were risks among CG II. Patients with CO-ESBL in CG I versus controls were more likely to die (30% vs 0%, respectively; P< .001), had prolonged hospital length of stay (8 vs 5 days, respectively; P< .001), and had higher hospitalization costs (median, US $528 vs $108, respectively; P< .001). The plasmid carrying the CTX-M-15 gene was identified in 13 of 25 (52%) available CO-ESBL-producing E coli isolates.

CONCLUSION

CO-ESBL-producing E coli is an emerging multidrug-resistant microorganism in Thailand. Patients with prior ESBL colonization and recent antibiotic exposures, especially to third-generation cephalosporins and fluoroquinolones, were at risk for CO-ESBL-producing E coli infection.

High presence of extended-spectrum β-lactamases and resistance to quinolones in clinical isolates of Escherichia coli

A study was conducted to detect the presence of extended-spectrum beta-lactamases (ESBLs) in 706 isolates of Escherichia coli, largely from outpatients (75.2%). The Clinical and Laboratory Standards Institute (formerly NCCLS)-recommended disk diffusion procedure was used to detect ESBL presence; the VITEK 2 system (bioMérieux, Marcy L'Etoile, France) was used to determine the susceptibility to antibiotics of clinical interest, and the ESBLs were characterized by biochemical study, determining the isoelectric point, and by molecular study with PCR. Clonal distribution was studied in eight hospital isolates. There were 115 ESBL-producing isolates (16.3%), with a predominance of CTX-M9 type (58.3%). We draw attention to the high resistance to quinolones (>70%) in CTX-M9 and SHV enzyme producing isolates and the lower aminoglycoside activity in the latter.

Contribution of a new mutation in parE to quinolone resistance in extended-spectrum-beta-lactamase-producing Escherichia coli isolates

Mutations in the quinolone resistance-determining regions of gyrA, gyrB, parC, and parE were studied in 30 fluoroquinolone-resistant clinical isolates of Escherichia coli producing extended-spectrum beta-lactamases. Ten isolates showed a mutation in parE that was significantly associated with an increase in the MIC for fluoroquinolones.