Detection of beta-lactamase-producing Enterobacteriaceae in a veterinary hospital environment / Detecção de Enterobactérias produtoras de beta-lactamases em ambiente hospitalar veterinário

Due to the strong selective pressure resulting from the misuse of antibiotics, the natural process of bacterial resistance has been accelerated, leading to the increasingly constant appearance of multiresistant isolates. The high number of multi-resistant bacteria is a one health problem. Enterobacteriaceae are usually commensal bacteria of the gastrointestinal tract. However, they can cause infections, and the most important resistance characteristic among them is the production of ß-lactamases. This study aimed to identify ESBL-producing Enterobacteriaceae of types of TEM, SHV, and the CTX-Mgroups. To isolate the enterobacteria, swabs were collected by swiping objects that had contact with the patients and professionals, and the water of the hospital environment. Ten collections were carried out, yielding 306 samples, from which 118 enterobacteria were identified: Escherichia coli, Enterobacter spp., Klebsiella spp., Proteus mirabilis, Serratiaspp., and Citrobacter spp. Isolates. The genes TEM and CTX-M, for the production of ß-lactamases, were detected in 12.7% of the 118 enterobacterial isolates. It is very important to know the bacterial population circulating in the veterinary hospital environment and its resistance to antimicrobials so that professionals can take appropriate measures to minimize the risks of transmission, especially from cages and consultation tables. In addition, the correct control of the microbiological quality of the supply water, as well as environmental cleaning procedures, are essential to prevent the transmission of these microorganisms.(AU)

Devido à grande pressão seletiva decorrente do uso indevido de antibióticos, tem se acelerado o processo natural de resistência das bactérias, levando ao aparecimento cada vez mais constante de isolados multirresistentes. O elevado número de bactérias multirresistentes identificadas é um problema da saúde única. As enterobactérias são bactérias geralmente comensais do trato gastrointestinal, entretanto podem causar infecções, e a característica de resistência mais importante entre elas é a produção de ß-lactamases. Buscando caracterizar melhor os microrganismos circulantes e potencialmente causadores de infecções em ambiente hospitalar veterinário, este estudo objetivou identificar as enterobactérias produtoras de ESBL do tipo TEM, SHV e os cinco grupos de CTX-M presentes em isolados circulantes em hospital veterinário. Foi realizada coleta de suabes de arrasto de objetos que entram em contato com os pacientes e com os profissionais que ali trabalham, bem como de água, para a identificação das enterobactérias. Foram realizadas 10 coletas, obtendo-se 306 amostras, dessas, 118 enterobactérias foram identificadas: Escherichia coli, Enterobacter, Klebsiella, Proteus mirabilis, Serratia e Citrobacter. Dentre as enterobactérias identificadas, alguns isolados possuíam genes para a produção de ß-lactamases, do tipo TEM e CTX-M. É de grande importância conhecer a população bacteriana circulante no ambiente hospitalar veterinário, e a sua resistência aos antimicrobianos, para que os profissionais possam tomar medidas apropriadas para minimizar os riscos de transmissão, principalmente a partir de gaiolas e mesas de atendimento. Além disso, o correto controle da qualidade microbiológica da água de abastecimento, bem como dos procedimentos de higienização do ambiente, são fundamentais para evitar a transmissão destes microrganismos.(AU)

Rapid Detection of Carbapenemase-producing Enterobacteriaceae From Blood Culture Bottles of Known CPE Carriers: Real-world Experience.

We used a rapid antigen test for the detection of carbapenemases directly from positive blood culture bottles of pediatric hemato-oncologic patients, known carriers of carbapenemase-producing enterobacteriaceae. Resistance mechanism was detected within 15 minutes of observing Gram-negative bacilli from a positive bottle, leading to treatment modification. This simple-to-use, inexpensive assay shortens the interval between empiric to tailored antimicrobial therapy.

Epidemiology, Risk Factors, and Clinical Outcomes of Bloodstream Infection due to Extended-Spectrum Beta-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae in Hematologic Malignancy: A Retrospective Study from Central South China.

Objective: To determine the epidemiology, risk factors, and prognosis of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae bloodstream infections (BSIs) among hematology malignancy (HM) patients in China. Method: From January 2010 to June 2018, we retrospectively collected and analyzed the 449 HM patients with E. coli or K. pneumoniae BSIs from three leading hospitals in Hunan Province, China. Results: Two hundred four (45.4%) patients harbored ESBL-producing bacteremia. The proportion of ESBL-producing bacteremia increased significantly with the growth of the year, with a ratio of 34.47% in 2010-2014 to 54.7% in 2015-2018. Comparing with non-ESBL groups in HM patients, central venous catheter (odds ratio [OR] 1.717, p = 0.009), previous antibiotic exposure (OR 1.559, p = 0.035), and E. coli (OR 2.561, p ≤ 0.001) among ESBL groups were independent risk factors. No significant differences in 30-day mortality were tested in patients with BSI caused by ESBL-producing or non-ESBL-producing E. coli and K. pneumoniae (17.1% vs. 16.7%; p = 0. 893). The proportion of carbapenem used within 72 hours after the onset of bacteremia in two groups was high, which was routinely used as "last-resort drugs" in Gram-negative bacterial infections. Risk factors associated with 30-day mortality in HM patients with E. coli or K. pneumoniae bacteremia were myelodysplastic syndrome, incomplete remission of the disease, Multinational Association of Supportive Care in Cancer score <21, Pitt bacteremia score ≥4, Charlson comorbidity score >3, catheter insertion, use of vasopressors, and inappropriate antibiotics within 72 hours of BSI onset. Conclusions: The results of this study may provide some references for the whole process management of HM patients with BSIs.

Association of intestinal colonization of ESBL-producing Enterobacteriaceae in poultry slaughterhouse workers with occupational exposure-A German pilot study.

BACKGROUND: Bacteria that have acquired antimicrobial resistance, in particular ESBL-producing Enterobacteriaceae, are an important healthcare concern. Therefore, transmission routes and risk factors are of interest, especially for the carriage of ESBL-producing E. coli. Since there is an enhanced risk for pig slaughterhouse employees to carry ESBL-producing Enterobacteriaceae, associated with animal contact as potential risk factor, the present study investigated the occurrence of ESBL-producing Enterobacteriaceae in poultry slaughterhouse employees. Due to the higher level of resistant Enterobacteriaceae in primary poultry production than in pig production, a higher risk of intestinal colonization of poultry slaughterhouse employees was expected. RESULTS: ESBL-producing Enterobacteriaceae were detected in 5.1% (5 of 99) of the fecal samples of slaughterhouse workers. The species of these isolates was confirmed as E. coli. PCR assays revealed the presence of the genes blaCTX-M-15 (n = 2) and blaSHV-12 (n = 3) in these isolates, partly in combination with the ß-lactamase gene blaTEM-135. Participants were divided into two groups according to their occupational exposure and results indicated an increased probability of colonization with ESBL-producing Enterobacteriaceae for the group of 'higher exposure' (OR 3.7, exact 95% CI 0.6-23.5; p = 0.4). For intestinal colonization with ESBL-producing Enterobacteriaceae, a prevalence of 10% (3/30) was observed in the group of 'higher exposure' versus 2.9% (2/69) in the group of 'lower exposure'. Employees in working steps such as 'hanging' poultry in the process of slaughter and 'evisceration' seemed to have a higher risk for intestinal colonization with ESBL-producing Enterobacteriaceae compared to the group of 'lower exposure'. CONCLUSION: This study is the first of its kind to collect data on the occupational exposure of slaughterhouse workers to ESBL-producing Enterobacteriaceae in Europe. The results suggested that colonization with ESBL-producing Enterobacteriaceae is associated with occupational exposure in poultry slaughterhouses. However, the presence of ESBL-producing E. coli isolates in only 5.1% (5/99) of the tested employees in poultry slaughterhouses suggests a lower transmission risk than in pig slaughterhouses.

Clinical and computed tomography features of extended-spectrum ß-lactamase-producing Klebsiella pneumoniae liver abscess.

BACKGROUND: Klebsiella pneumoniae (KP) is the primary pathogen associated with pyogenic liver abscesses (PLAs). Moreover, there has been an increase in the proportion of extended-spectrum beta-lactamase (ESBL)-producing KP. However, the clinical and computed tomography (CT) features of liver abscesses caused by ESBL-producing KP have not been separately described. We aimed to compare the clinical and CT features present in patients with ESBL-producing and non-ESBL-producing KP as well as to determine the risk factors for ESBL-producing KP liver abscesses (KPLAs). METHODS: We performed a retrospective analysis of data obtained from the medical records of patients with a first episode of KPLA admitted to Shengjing Hospital of China Medical University between May 2015 and May 2019. We compared the clinical and CT features between patients with ESBL-producing and non-ESBL-producing KPLA. RESULTS: We enrolled 100 patients with KPLA (14 and 86 in the ESBL-producing and non-ESBL-producing groups, respectively). There was no significant between-group difference in the proportion of patients with comorbid diabetes (71.43% vs. 66.2%, p = 0.086). The ESBL-producing KPLA group had a greater proportion of patients with a history of biliary disease (78.57% vs. 26.74%, p < 0.001) and gastrointestinal malignancy (50% vs. 6.98%, p < 0.001). Multivariate regression analysis showed that a history of biliary disease was an independent risk factor for ESBL-producing KPLA. Compared with the non-ESBL-producing KPLA group, the ESBL-producing KPLA group had a significantly higher intensive care unit (ICU) admission rate (28.57% vs. 2.33%, p < 0.001). All ESBL-producing KP isolates were susceptible to carbapenems and amikacin. Only the presence of multiloculation on CT was found to be significantly different between the groups (50% vs. 82.56%, p = 0.012). CONCLUSIONS: The presence of biliary disease was an independent risk factor for ESBL-producing KPLA. Patients with ESBL-producing KPLA had a higher ICU admission rate, with only half of patients having evidence of multiloculation on CT.

Presencia de genes fimH y afa en aislamientos urinarios de Escherichia coli productora de betalactamasas de espectro extendido en Lima, Perú / Presence of fimH and afa genes in urinary isolates of extended-spectrum beta-lactamases producing Escherichia coli in Lima, Peru

RESUMEN Con el objetivo de determinar la presencia de los genes fimH y afa en aislamientos urinarios de Escherichia coli productoras de betalactamasas de espectro extendido (BLEE), se realizó un estudio descriptivo, con aislamientos del cepario del proyecto TO-06/09 del Instituto Nacional de Salud del Niño en Lima, Perú. Se incluyeron 75 aislamientos urinarios de Escherichia coli. La identificación de genes se realizó por reacción en cadena de la polimerasa. De los 75 aislamientos, 74 (98,7%) fueron positivos para el gen fimH y 6 (8,0%) fueron positivos para el gen afa. Se evidenció la presencia de los factores de virulencia producidos por los genes fimH y afa en aislamientos urinarios de Escherichia coli productoras de BLEE.

ABSTRACT Descriptive study conducted in order to determine the presence of the fimH and afa genes in urinary isolates of extended-spectrum beta-lactamases (ESBL) producing Escherichia coli. Isolates from project TO-06/09 of the Instituto Nacional de Salud del Niño in Lima, Peru were used. A total of 75 urinary isolates of Escherichia coli were included. Gene identification was performed by polymerase chain reaction. From the 75 isolates, 74 (98.7%) were positive for the fimH gene and 6 (8.0%) were positive for the afa gene. Virulence factors produced by the fimH and afa genes were evident in urinary isolates of ESBL producing Escherichia coli.

Molecular characterization of carbapenem-resistant Klebsiella pneumoniae ST14 and ST512 causing bloodstream infections in ICU and surgery wards of a tertiary university hospital of Verona (northern Italy): co-production of KPC-3, OXA-48, and CTX-M-15 ß-lactamases.

Klebsiella pneumoniae strain is an important opportunistic pathogen that causes severe nosocomial infections. In the present study a molecular characterization of carbapenem resistant K. pneumoniae, isolated from blood samples of hospitalized patients of Verona University Hospital, was performed. The simultaneous presence of SHV-1/CTX-M-15/KPC-3 and SHV-1/CTX-M-15/OXA-48 serin-ß-lactamases was ascertained in the 89% and 11% of K. pneumoniae ST512 and K. pneumoniae ST14, respectively. Molecular characterization of bla genes showed that blaKPC-3 was found in Tn4401a transposon with the tnpR, tnpA, ISKpn6, and ISKpn7 mobile elements whereas blaCTX-M-15 was detected downstream ISEcp1 genetic element. A class 1 integron with a gene cassette of 780 bp corresponding to aadA2 gene was identified in 33 K. pneumoniae ST512 isolates.

Extended-spectrum beta-lactamase-producing enterobacterales carrying the mcr-1 gene in Lima, Peru. / Enterobacterales productores de betalactamasas de espectro extendido portadores del gen mcr-1 en Lima, Perú.

We analyzed the presence of the mcr-1 gene in 165 extended-spectrum beta-lactamase-producing enterobacterales (ESBL-PE) obtained during 2017, from blood (40), urine (57), lower respiratory secretions (12) and rectal swabs (56) of patients hospitalized in the Instituto Nacional de Enfermedades Neoplásicas (Peru). Antimicrobial identification and susceptibility were determined by the Phoenix M50 automated system; colistin resistance by Colistin Agar-Spot (CAS); mrc-1 detection by colistin pre-diffusion and inhibition with EDTA test (CPD-E) and by polymerase chain reaction (PCR). We found that from the 165 ESBL-PE, 25 were positive for mcr-1 by the CPD-E method and confirmed by PCR. Colistin resistance was found in 20/165 by using the CAS method. Additionally, they showed resistance to fluoroquinolones and gentamicin, while remaining sensitive to amikacin; two isolates presented metallo-carbapenemases. Obtaining data on resistance to last-line antimicrobials (colistin) is crucial to establish measures for its control.

Se analizó la presencia del gen mcr-1 en 165 enterobacterales productores de betalactamasas de espectro extendido (EP-BLEE) recuperados en 2017 de sangre (40), orina (57), secreciones respiratorias bajas (12) e hisopados rectales (56) de pacientes hospitalizados en el Instituto Nacional de Enfermedades Neoplásicas (Perú). La identificación y la susceptibilidad antimicrobiana se determinaron por el sistema automatizado Phoenix M50; la resistencia a colistina por Colistin Agar-Spot (CAS); la detección de mrc-1 por el método fenotípico de predifusión de colistina e inhibición con EDTA (CPD-E) y por reacción en cadena de la polimerasa (PCR, por sus siglas en inglés). De los 165 EP-BLEE 25 fueron positivos para mcr-1 por el método CPD-E y se confirmó por PCR. Por el método CAS, 20/165 fueron resistentes a colistina. Además, mostraron resistencia a las fluoroquinolonas y a la gentamicina, y permanecieron sensibles a la amikacina; dos aislamientos presentaron metalocarbapenemasas. La obtención de datos sobre la resistencia a antimicrobianos considerados de última línea (colistina) es crucial para establecer medidas para su control.

Comparison of the inoculum size effects of antibiotics on IMP-6 ß-lactamase-producing Enterobacteriaceae co-harboring plasmid-mediated quinolone resistance genes.

Almost all cases of carbapenemase-producing Enterobacteriaceae infections in Japan are caused by blaIMP-positive Enterobacteriaceae (especially blaIMP-6) and infections caused by other types of carbapenemase-producing Enterobacteriaceae are quite rare. We examined drug resistance genes co-harboring with blaIMP-6 and their inoculum size effects. We screened ß-lactamase genes, plasmid-mediated quinolone resistance (PMQR) genes, and aminoglycoside-modifying enzyme genes by PCR and performed sequencing for 14 blaIMP-6-positive Enterobacteriaceae. Further, all PMQR-positive isolates were submitted to conjugation and inoculum effect evaluation. Our data showed that 13 of the 14 isolates harbored CTX-M-2 and one co-harbored CTX-M-2 and CTX-M-1 as extended-spectrum ß-lactamases. All isolates carried one or more PMQRs; aac(6')-Ib-cr was the most prevalent (92.8%), and was followed by oqxA (64.3%), qnrS (50%), oqxAB (21.4%), and qnrB (14.3%). However, Klebsiella pneumoniae contains chromosomal OqxAB. Inoculum size effects were significant in all strains for meropenem, 13 strains for imipenem, 7 for levofloxacin, and 3 for amikacin. We observed that 11 of the experimental strains (100%), 8 strains (72.7%), and 1 strain showed inoculum size effects for meropenem, imipenem, and amikacin, respectively. However, four strains harbored qnr genes and two strains harbored qnr genes and QRDR mutations concurrently; no inoculum size effect was seen for levofloxacin. The blaIMP-6-positive Enterobacteriaceae that we studied was found to harbor at least one plasmid-mediated drug resistance gene. The inoculum size effect for carbapenems was thought to be mainly due to IMP-6-type metallo-ß-lactamase; however qnrB and qnrS also had a minimal impact on the inoculum size effect for levofloxacin.

Prevalencia de β -lactamasas de espectro extendido en enterobacterias causantes de sepsis neonatal y factores asociados / Prevalence of extended-spectrum beta-lactamases in enterobacteria of neonatal sepsis and associated factors

Resumen Introducción: Las infecciones causadas por enterobacterias productoras de β-talactamasas de espectro extendido (EP-BLEE) tienen implicaciones sobre la morbilidad y mortalidad neonatal. Objetivo: Describir la prevalencia de EP-BLEE en sepsis neonatal y los factores asociados. Métodos: Estudio de cohorte prospectivo, desde agosto del 2016 a agosto del 2017. Se incluyeron recién nacidos (RNs) ingresados en el Hospital Civil de Guadalajara "Dr. Juan I. Menchaca". Mediante prueba de difusión de doble disco se indagó la presencia de EP-BLEE y su asociación con características clínicas y demográficas de los RNs. Resultados: Se estudiaron 1.501 RNs hospitalizados, con edad gestacional promedio de 36,3 semanas. Se diagnosticaron 196 eventos de sepsis neonatal, la etiología más frecuente fueron enterobacterias (45,5%); 88,8% demostraron resistencia a ampicilina y más de 42% a cefalosporinas de amplio espectro. El 22,9% presentó fenotipo BLEE positivo. Tener Apgar ≤ 7 a los cinco minutos de vida (OR 4,6; IC 95% 1,47-14,6) y edad gestacional < 37 semanas (OR 5,4; IC 95%1,04-27,7) incrementaron el riesgo. Conclusión: En las enterobacterias causantes de sepsis neonatal, 22,9% son EP-BLEE; la infección es más probable en pacientes con Apgar ≤ 7 a los cinco minutos de vida y en prematuros.

Background: Infections caused by extended-spectrum beta-lactamases enterobacteria (ESBL-EP) have implications for neonatal morbidity and mortality. Aim: To describe the prevalence of ESBL-EP in neonatal sepsis and associated factors. Methods: A prospective cohort study was conducted from August 2016 to August 2017; newborn babies (NB) hospitalized in the Hospital Civil de Guadalajara "Dr. Juan I. Menchaca" were included. The ESBL-EP were investigated by double-disk synergy test and its association with clinical and demographic characteristics of the NB. Results. A total of 1,501 hospitalized NB were studied, with an average gestational age of 36.3 weeks. They were diagnosed 196 neonatal sepsis events, the most frequent etiologies were enterobacteria (45.5%). Resistance to ampicilin was found in 88.8% and to broad spectrum cephalosporins in more than 42% of the strains; 22.9% of them were ESBL phenotype. Apgar ≤ 7 at five minutes of life (OR 4.6; 95% CI 1.47-14.6) and gestational age < 37 weeks (OR 5.4; 95% CI 1.04-27.) increase the risk. Conclusion: In enterobacteria that cause neonatal sepsis, 22.9% were EP-ESBL; infection was more likely in patients with Apgar ≤ 7 at five minutes of age and in preterm infants.

Antimicrobial susceptibility and impact of macrolide antibiotics on Moraxella catarrhalis in the upper and lower airways of children with chronic endobronchial suppuration.

INTRODUCTION: Moraxella catarrhalis is an important but insufficiently studied respiratory pathogen. AIM: To determine antibiotic susceptibility and impact of recent antibiotics on M. catarrhalis from children with chronic endobronchial suppuration. METHODOLOGY: We cultured nasopharyngeal (NP) swabs and bronchoalveolar lavage (BAL) fluids collected from children who were prospectively enrolled in studies of chronic cough and had flexible bronchoscopy performed. Recent ß-lactam or macrolide antibiotic use was recorded. M. catarrhalis isolates stored at -80 °C were re-cultured and susceptibility determined to a range of antibiotics including the macrolide antibiotic erythromycin. RESULTS: Data from concurrently collected NP and BAL specimens were available from 547 children (median age 2.4 years) enrolled from 2007 to 2016. M. catarrhalis NP carriage was detected in 149 (27  %) children and lower airway infection (≥104 c.f.u. ml-1 BAL) in 67 (12  %) children. In total, 91  % of 222 M. catarrhalis isolates were ß-lactamase producers, and non-susceptibility was high to benzylpenicillin (98 %), cefaclor (39 %) and cotrimoxazole (38 %). Overall, >97  % isolates were susceptible to cefuroxime, chloramphenicol, erythromycin and tetracycline; three isolates were erythromycin-resistant (MIC >0.5 mg l-1). Recent macrolide antibiotics (n=152 children, 28 %) were associated with significantly reduced M. catarrhalis carriage and lower airway infection episodes compared to children who did not receive macrolides; odds ratios 0.19 (95  % CI 0.10-0.35) and 0.15 (0.04-0.41), respectively. CONCLUSION: Despite the frequent use of macrolides, few macrolide-resistant isolates were detected. This suggests a fitness cost associated with macrolide resistance in M. catarrhalis. Macrolide antibiotics remain an effective choice for treating M. catarrhalis lower airway infection in children with chronic endobronchial suppuration.

Graphene/nickel oxide nanocomposites against isolated ESBL producing bacteria and A549 cancer cells.

The synthesis of nickel oxide nanoparticles (NiO NPs) and graphene/nickel oxide nanocomposites (Gr/NiO NCs) was performed using a simple chemical reduction method. Powder X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were used to examine the crystalline nature and thermal stability of the synthesized NiO NPs and Gr/NiO NCs, respectively. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were utilized to observe the morphology of NiO NPs and Gr/NiO NCs and estimate their size range. TEM suggested that the NiO NPs were speared onto the surface of Gr nanosheet. The efficiency of NiO NPs and Gr/NiO NCs against extended spectrum ß-lacamase (ESBL) producing bacteria, which was confirmed by specific HEXA disc Hexa G-minus 24 (HX-096) and MIC strip methods (CLSI); namely Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) was investigated using the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) methods. MIC results suggested that the NiO NPs and Gr/NiO NCs possess maximum growth inhibition of 86%, 82% and 94%, 92% at 50 and 30 µg/mL concentrations, respectively. Similarly, both nanomaterials were found to inhibit the ß-lacamase enzyme at concentrations of 60 µg/mL and 40 µg/mL, respectively. The cytotoxicity of NiO NPs and Gr/NiO NCs was quantified against A549 human lung cancer cells. Cell death percentage values of 52% at 50 µg/mL against NiO NPs and 54% at 20 µg/mL against Gr/NiO NCs were obtained, respectively. The NCs were found to reduce cell viability, increase the level of reactive oxygen species (ROS) and modify both the mitochondrial membrane permeability and cell cycle arrest.

Phylogenetic analysis of resistance to ceftazidime/avibactam, ceftolozane/tazobactam and carbapenems in piperacillin/tazobactam-resistant Pseudomonas aeruginosa from cystic fibrosis patients.

Pseudomonas aeruginosa is one of the most important pathogens in cystic fibrosis. This study was conducted to analyse the genetic basis and phylogenetic profile of resistance to ceftazidime/avibactam, ceftolozane/tazobactam and carbapenems in cystic fibrosis P. aeruginosa isolates. Whole genome sequence analysis was conducted of isolates resistant to piperacillin/tazobactam collected from seven hospitals in Scotland since the introduction of these two cephalosporin/ß-lactamase inhibitor combinations. Ceftazidime resistance was primarily related to AmpC induction, as tested by cloxacillin inhibition assays, while high-level ceftazidime resistance not reversed by cloxacillin was associated with amino acid variations in AmpC. Only isolates resistant to both ceftazidime/avibactam and ceftolozane/tazobactam carried AmpD mutations, likely resulting in ampC overexpression. All isolates resistant to ceftazidime/avibactam and/or ceftolozane/tazobactam were resistant to carbapenems and showed inactivating mutations in the chromosomal oprD gene. None of the isolates bore class A, B, D plasmid-encoded carbapenemases. This study showed that mutational resistance emerged in phylogenetically distant lineages, which indicates the mutations occur independently without conferring a selective advantage to any phylogenetic lineage. These findings confirm the strong contribution of mutation-driven evolution to the population structure of P. aeruginosa.

Investigation of risk factors for community-acquired urinary tract infections caused by extended-spectrum beta-lactamase Escherichia coli and Klebsiella species.

PURPOSE: The aim of this study was to determine the prevalence and risk factors for community-acquired urinary tract infections (CA-UTIs) caused by extended-spectrum ß-lactamase (ESBL) producing Escherichia coli and Klebsiella species. MATERIALS AND METHODS: The patients diagnosed with CA-UTIs caused by E. coli or Klebsiella spp. were included in the study. All of the patients were compared to demographic characteristics, underlying diseases, urinary tract pathology, history of hospitalization, use of antibiotics according to ESBL positivity. RESULTS: A total of 322 urine isolates were studied. Sixty-six patients (37.1%) of a total of 178 patients were ESBL positive E. coli and Klebsiella spp. Being over the age of sixty (odds ratio [OR], 1.90; p=0.03), history of renal stone (OR, 3.00; p=0.03), urinary tract anatomical of physiological disorder (OR, 2.17; p=0.01), urologic intervention (OR, 3.43; p<0.001), history of urinary tract surgery (OR, 3.10; p=0.01), history of urinary catheterization (OR, 3.43; p<0.001), and hospitalization for last 1 year (OR, 3.70; p=0.01) and antibiotic usage in the last 3 months (OR, 1.90; p=0.04) were found as significant risk factors for the producing of ESBL. However, gender and underlying disease were not related for ESBL production. CONCLUSIONS: In present study, high rate of ESBL positivity was detected in CA-UTIs. The increasing of infections caused by ESBL positive E. coli and Klebsiella spp. are bringing together a lot of the problem, such as antibiotic resistance and reducing treatment options for outpatients. Identification of underlying risk factors would be important for the development of preventive strategies.