In Vitro Activity of Omadacycline and Comparator Antibiotics against Extended-Spectrum Beta-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae Urinary Isolates.

Limited oral antibiotic options exist for urinary tract infections (UTI) caused by ESBL-producing Enterobacterales. The aim of the study was to evaluate in vitro activity of omadacycline and comparator antibiotics against clinical ESBL-producing and non-ESBL-producing E. coli and K. pneumoniae urinary isolates. 102 isolates each of E. coli and K. pneumoniae were collected from clinical urine specimens in 2019. By design, an equal number of each species were included that tested positive and negative for ESBL production. Omadacycline MICs were determined using gradient test strips and compared to MICs of comparator antibiotics as determined by an automated broth microdilution system. Isolates were considered susceptible to omadacycline if the MIC was ≤4 µg/mL for each species. 54.9% of all ESBL-producing isolates were susceptible to omadacycline, but better susceptibility was observed for ESBL-producing E. coli (74.5%). Omadacycline MICs were 2-4 fold lower for E. coli and K. pneumoniae strains not producing ESBL. The omadacycline MIC 50 and 90 values were 4 and 16 µg/mL, respectively, for all isolates studied. 74.5% of all isolates were considered susceptible to omadacycline. MICs were generally lower for E. coli strains with MIC 50 and 90 values of 4 and 8 µg/mL, respectively (87.3% susceptible), compared with K. pneumoniae. Overall, the most active agents were omadacycline and nitrofurantoin, while other comparator antibiotics were less active. Omadacycline represents a promising oral antibiotic for treating UTI caused by ESBL-producing E. coli, particularly when resistance limits other oral options. Prospective, controlled clinical trials are needed to validate these in vitro results.

Clinical impact of a multiplex rapid diagnostic pneumonia panel in critically ill patients.

Objective: To evaluate the clinical impact of the BioFire FilmArray Pneumonia Panel (PNA panel) in critically ill patients. Design: Single-center, preintervention and postintervention retrospective cohort study. Setting: Tertiary-care academic medical center. Patients: Adult ICU patients. Methods: Patients with quantitative bacterial cultures obtained by bronchoalveolar lavage or tracheal aspirate either before (January-March 2021, preintervention period) or after (January-March 2022, postintervention period) implementation of the PNA panel were randomly screened until 25 patients per study month (75 in each cohort) who met the study criteria were included. Antibiotic use from the day of culture collection through day 5 was compared. Results: The primary outcome of median time to first antibiotic change based on microbiologic data was 50 hours before the intervention versus 21 hours after the intervention (P = .0006). Also, 56 postintervention regimens (75%) were eligible for change based on PNA panel results; actual change occurred in 30 regimens (54%). Median antibiotic days of therapy (DOTs) were 8 before the intervention versus 6 after the intervention (P = .07). For the patients with antibiotic changes made based on PNA panel results, the median time to first antibiotic change was 10 hours. For patients who were initially on inadequate therapy, time to adequate therapy was 67 hours before the intervention versus 37 hours after the intervention (P = .27). Conclusions: The PNA panel was associated with decreased time to first antibiotic change and fewer antibiotic DOTs. Its impact may have been larger if a higher percentage of potential antibiotic changes had been implemented. The PNA panel is a promising tool to enhance antibiotic stewardship.

Evaluation of the Potential Impact of a Multiplex Rapid Diagnostic Panel in Critically Ill Patients With Hospital-Acquired Pneumonia.

Background Rapid diagnostic tools have emerged as valuable assets assisting clinicians in decision-making regarding patient management in the hospital setting. Our study sought to identify the potential impact of the BioFire® FilmArray® Pneumonia Panel (FP Panel) (BioFire Diagnostics, Salt Lake City, UT, USA) in patients with hospital-acquired pneumonia (HAP). Methods Respiratory samples obtained by bronchoalveolar lavage (BAL) or tracheal aspiration (TA) from ICU patients with a diagnosis of HAP were tested by the FP panel in addition to routine bacterial cultures. In addition, the electronic health records of these patients were reviewed to determine what potential changes in antimicrobial therapy could have been implemented if the panel results were known to the treatment team in real-time. A cost analysis was also performed incorporating the cost of the pneumonia panel and the savings associated with the potential decrease of antibiotic use and avoidance of the rapid viral diagnostic panel.  Results Fifty-six patients met the study criteria. The FP panel results could have prompted a change in therapy in 36 (64.3%) patients, with an anticipated mean reduction in time to optimized therapy of approximately 51 hours. In addition, the panel identified three cases where antimicrobials should have been altered because patients were not receiving empiric therapy with activity against the causative pathogen and 34 opportunities for antibiotic de-escalation. The cost analysis calculated an additional cost of $10 per patient associated with using the FP panel.  Conclusions The FP panel could have prompted a change in therapy in about two-thirds of patients studied. Its potential benefits include a more rapid time to optimized therapy, reduced exposure to and cost of broad-spectrum antimicrobials, and reduced cost of other rapid diagnostic tests.

Factors associated with increased intra-abdominal pressure in patients undergoing cardiac surgery.

BACKGROUND: The aim of this study was to investigate the intra-abdominal pressure changes and risk factors associated with increased intra-abdominal pressure in patients undergoing cardiac surgery. METHODS: Between July 2016 and January 2017, a total of 100 patients (74 males, 26 females; mean age 55.9±14.3 years; range, 19 to 75 years) who underwent cardiac surgery under cardiopulmonary bypass were included in the study. Patients" data including demographic and clinical characteristics and intra- and postoperative data were recorded. Intra-abdominal pressure was measured via a urinary catheter after anesthesia induction, on admission to the intensive care unit, and at postoperative 12 and 24 h. The patients were divided into two groups according to the intraabdominal pressure as Group 1 (≥12 mmHg; n=49) and Group 2 (<12 mmHg; n=51). RESULTS: In the univariate regression analysis, high intra-abdominal pressure was related to intra-abdominal pressure measured after anesthesia induction (Odds Ratio =0.70, p=0.001), age (odds ratio=0.95, p=0.004), hypertension (odds ratio=4.51, p=0.0001), duration of cardiopulmonary bypass (odds ratio=0.97, p=0.0001), intraoperative lactate levels (odds ratio=0.53, p=0.0001), use of red blood cells (odds ratio=0.24, p=0.0001), use of dopamine (odds ratio=0.21, p=0.002), dobutamine (odds ratio=0.28, p=0.005), use of noradrenaline (odds ratio=0.25, p=0.016), postoperative lactate levels (odds ratio=0.60, p=0.0001), duration of cross-clamp (odds ratio=0.97, p=0.0001), atrial fibrillation (odds ratio=5.89, p=0.004), and acute kidney injury (odds ratio=8.33, p=0.048). In the multivariate analysis, the intra-abdominal pressure at baseline (odds ratio=0.70, p=0.045), age (odds ratio=0.93, p=0.032), hypertension (odds ratio=6.87, p=0.023), duration of cardiopulmonary bypass (odds ratio=0.98, p=0.062), intraoperative lactate levels (odds ratio=0.57, p=0.035), and use of red blood cells (odds ratio=0.19, p=0.003) remained statistically significant. CONCLUSION: Our study results suggest that age, hypertension, duration of cardiopulmonary bypass, intraoperative lactate levels, and use of red blood cells are risk factors associated with elevated intra-abdominal pressure in patients undergoing cardiac surgery. Increased awareness of these risk factors and the addition of intra-abdominal pressure measurement to the standard follow-up scheme in patients with variable hemodynamics, low cardiac output, and high lactate levels in the intensive care unit may be useful in early diagnosis of complications and in decreasing morbidity.

First Case of High-Level Azithromycin-Resistant Neisseria gonorrhoeae in North Carolina.

We report on the first high-level azithromycin-resistant Neisseria gonorrhoeae isolate (minimum inhibitory concentration, ≥256 µg/mL) in North Carolina isolated from a pharyngeal swab of a 33-year-old HIV-negative man who has sex with men. In addition, the isolate was found to be susceptible to cefixime, ceftriaxone, and penicillin and resistant to tetracycline. By whole-genome sequencing, the strain was assigned as MLST ST9363, NG-MAST ST5035, and a novel NG-STAR sequence type, ST1993.

Rapid Identification of Klebsiella pneumoniae by Matrix-Assisted Laser Desorption/Ionization-Time of Flight Mass Spectrometry and Detection of Meropenem Resistance by Flow Cytometric Assay.

BACKGROUND: The aim of this study was to develop a rapid detection method of carbapenem-resistant Klebsiella pneumoniae (CRKP) strains both MALDI-TOF MS and flow cytometry (FCM). METHODS: A total of 174 K. pneumoniae strains were included in this study. Molecular characterization of carbapenemase gene was performed by PCR. Bacterial identification was performed by MALDI-TOF-MS. Meropenem susceptibility was tested at the concentrations of breakpoints described by the Clinical and Laboratory Standards Institute (CLSI) guide by FCM. RESULTS: Sixty-two CRKP were positive for at least one carbapenemase gene. A total of 174 K. pneumoniae isolates obtained from clinically relevant material were correctly identified by Bruker MALDI-TOF MS with log (score) >2.0. These results were 100% concordant with the Phoenix™ Automated Microbiology System (BD, MD) and conventional identification results. Based on the analysis of the receiver operating characteristic (ROC) curves, the best validity and sensitivity data were obtained with a cut-off value of 18.88% by FCM. The concordance, sensitivity, and specificity for FCM by the selected cut-off values were 99.4%, 98.9%, and 100%, respectively. CONCLUSIONS: We conclude that reliable results on bacterial identification and meropenem susceptibility test can be obtained within 2 hr combined by MALDI-TOF-MS and FCM.

[Investigation of carbapenemases in carbapenem-resistant Escherichia coli and Klebsiella pneumoniae strains isolated in 2014 in Turkey]. / Türkiye'de 2014 yili içinde izole edilen karbapeneme dirençli Escherichia coli ve Klebsiella pneumoniae izolatlarinda karbapenemaz varliginin arastirilmasi.

Carbapenems are the choice of treatment in infections caused by multidrug resistant Enterobacteriaceae. In recent years carbapenem-resistant Enterobacteriaceae isolates due to carbapenemases have been increasingly reported worldwide. Multicenter studies on carbapenemases are scarce in Turkey. The aim of this study was to determine the distribution of carbapenemases from different parts of Turkey as a part of the European Survey of Carbapenemase Producing Enterobacteriaceae (EuSCAPE) project. Beginning in November 2013, carbapenem-resistant isolates resistant to at least one of the agents, namely imipenem, meropenem, and ertapenem were sent to the coordinating center. Minimum inhibitory concentrations for these carbapenems were determined by microdilution tests following EUCAST guidelines. Production of carbapenemase was confirmed by combination disk synergy tests. Types of carbapenemases were investigated using specific primers for VIM, IMP; NDM, KPC and OXA-48 genes by multiplex polymerase chain reaction. In a six month period, 155 suspected carbapenemase-positive isolates were sent to the coordinating center of which 21 (13.5%) were E.coli and 134 (86.5%) were K.pneumoniae. Nineteen (90.5%) strains among E.coli and 124 (92.5%) strains among K.pneumoniae were shown to harbour at least one carbapenemase gene by molecular tests, with a total of 92.3% (143/155). Carbapenemases were determined as a single enzyme in 136 strains (OXA-48: 84.6%; NDM: 6.3%; VIM: 2.8%; IMP: 1.4%) and as a combination in seven isolates (OXA-48 + NDM: 2.1%; OXA-48 + VIM: 2.1%; VIM + NDM: 0.7%). KPC was not detected in any of the isolates. According to the microdilution test results, resistance to imipenem, meropenem and ertapenem in OXA-48 isolates were 59.5%, 52.9% and 100%, respectively. The combination disk synergy test was 100% compatible with the molecular test results. As most of the OXA-48 producing isolates were susceptible to meropenem but all were resistant to ertapenem, ertapenem seems to be the most sensitive agent in screening carbapenemases in areas where OXA-48 is prevalent and phenotypic combination tests can be useful in centers where molecular tests are not available.

A Multicenter Evaluation of Blood Culture Practices, Contamination Rates, and the Distribution of Causative Bacteria.

BACKGROUND: The prognostic value of blood culture testing in the diagnosis of bacteremia is limited by contamination. OBJECTIVES: In this multicenter study, the aim was to evaluate the contamination rates of blood cultures as well as the parameters that affect the culture results. MATERIALS AND METHODS: Sample collection practices and culture data obtained from 16 university/research hospitals were retrospectively evaluated. A total of 214,340 blood samples from 43,254 patients admitted to the centers in 2013 were included in this study. The blood culture results were evaluated based on the three phases of laboratory testing: the pre-analytic, the analytic, and the post-analytic phase. RESULTS: Blood samples were obtained from the patients through either the peripheral venous route (64%) or an intravascular catheter (36%). Povidone-iodine (60%) or alcohol (40%) was applied to disinfect the skin. Of the 16 centers, 62.5% have no dedicated phlebotomy team, 68.7% employed a blood culture system, 86.7% conducted additional studies with pediatric bottles, and 43.7% with anaerobic bottles. One center maintained a blood culture quality control study. The average growth rate in the bottles of blood cultures during the defined period (1259 - 26,400/year) was 32.3%. Of the growing microorganisms, 67% were causative agents, while 33% were contaminants. The contamination rates of the centers ranged from 1% to 17%. The average growth time for the causative bacteria was 21.4 hours, while it was 36.3 hours for the contaminant bacteria. The most commonly isolated pathogens were Escherichia coli (22.45%) and coagulase-negative staphylococci (CoNS) (20.11%). Further, the most frequently identified contaminant bacteria were CoNS (44.04%). CONCLUSIONS: The high contamination rates were remarkable in this study. We suggest that the hospitals' staff should be better trained in blood sample collection and processing. Sterile glove usage, alcohol usage for disinfection, the presence of a phlebotomy team, and quality control studies may all contribute to decreasing the contamination rates. Health policy makers should therefore provide the necessary financial support to obtain the required materials and equipment.

[Investigation of the presence of mecC and Panton-Valentine leukocidin genes in Staphylococcus aureus strains isolated from clinical specimens during seven years period]. / Yedi yillik sürede klinik örneklerden izole edilen Staphylococcus aureus suslarinda mecC ve Panton-Valentine lökosidin gen varliginin arastirilmasi.

Detection and identification of methicillin-resistant Staphylococcus aureus (MRSA) in clinical microbiology laboratories are important for the selection of appropriate treatment and obtaining epidemiological data. mecC gene, is a mecA homologue, showing almost 69% DNA similarity with the mecA gene and the encoded protein by this gene shows almost 63% similarity with the PBP2a/2' protein. Several studies indicated that mecC positive MRSA strains can be transmitted from the livestock to humans by cross contamination. Panton-Valentine leukocidin (PVL), a potent cytotoxin of S.aureus is also considered as an important virulence factor. The aim of this study was to determine the existence and prevalence of mecC and pvl genes among S.aureus strains isolated from clinical specimens. A total of 1700 S.aureus isolates including 1177 methicillin-susceptible S.aureus (MSSA) and 523 MRSA, isolated in our hospital between January 2007 to December 2014, were included in the study. The isolates were identified by both conventional methods and BD Phoenix automated system (BD Diagnostic Instrument Systems, USA). Antibiotic susceptibility testing was performed by Kirby-Bauer disk diffusion method with oxacillin (1 µg) and cefoxitin (30 µg) according to the CLSI standards. The presence of mecA gene was investigated by the use of real-time PCR, and the presence of pvl and mecC genes were detected by conventional PCR method. Among the patients, 44.6% (759/1700) were outpatients, 65.8% (1119/1700) were male and the mean age of of patients was 39.7 years. Of 1700 isolates evaluated in this study, 523 (30.7%) were positive for mecA gene, however all of them were negative for mecC gene. A total of 32 (1.8%) isolates were positive for pvl gene including 23 (1.9%) out of 1177 MSSA and nine (1.7%) out of 523 MRSA strains. Eighteen (56.2%) of the PVL-positive S.aureus strains were isolated from skin and soft tissue infections. The frequency of PVL detected in this study was similar to the data of previous studies in our country. To the best of our knowledge, this is the first study for the determination of the mecC in our country. Although the mecC gene positive S.aureus has not been detected in our study, it should be kept in mind that the regional epidemiological conditions can vary quickly. In conclusion, multicenter studies are needed for the screening of mecC gene including the animal isolates, in Turkey.

[Rapid detection of extended-spectrum beta-lactamases by flow cytometry method]. / Genislemis spektrumlu beta-laktamazlarin akim sitometrisi yöntemiyle hizli tespiti.

Extended-spectrum beta-lactamases (ESBL), produced by Enterobacteriaceae members are enzymes that especially cause a resistance to cephalosporin group antibiotics commonly used in clinics. Early and rapid detection of ESBL production is crucial for antimicrobial treatment and infection control; however the methods used for this purpose are time consuming (24 to 48 hours). The aim of this study was to determine a flow cytometry based-test which provides to detect ESBL producing bacteria in a short time. A total of 38 ESBL-producing (29 Escherichia coli, 9 Klebsiella pneumoniae) and 10 non-producing (5 E.coli, 5 K.pneumoniae) Enterobacteriaceae strains isolated between 2012 and 2013 were included in this study. The identification and antibiotic susceptibility tests of the isolates were performed by using Phoenix(TM) 100 automated system (Becton Dickinson, USA). The presence of bla(TEM), bla(SHV), bla(CTX-M1), bla(CTX-M2) and bla(CTX-M9) genes were investigated in ESBL positive isolates via polymerase chain reaction method. At least one of the ESBL genes were detected in 36 out of 38 isolates and no genes were detected in two E.coli isolates. In flow cytometric method, the percentages of death cells exposed to cephalosporin [(ceftazidime (CAZ) or cefotaxime (CTX)] and clavulanic acid (CLA) combination, were compared with death cells exposed only to cephalosporin (CAZ or CTX). CLA index values (CAZ-CLA and CTX-CLA indices) were obtained for CTX and CAZ. Index values which was higher than 1.5 just for one cephalosporin were accepted as GSBL positive. The mean index values for CTX-CLA in ESBL positive strains according to their genotypic characteristics were between 1.14 and 7.22, while those values for CAZ-CLA were between 0.85 and 5.6. When the two groups of 38 ESBL positive and 10 ESBL negative strains were evaluated, statistically significant difference was detected for both CAZ-CLA and CTX-CLA indices (p< 0.005). CTX-CLA indices (p= 0.001) shown a better determination of ESBL when CAZ-CLA and CTX-CLA indices were compared statistically. In conclusion, flow cytometry is a rapid and reliable method for the detection of ESBL in clinical microbiology laboratories when compared with the other methods.

Multiplex Real-Time PCR Method for Simultaneous Identification and Toxigenic Type Characterization of Clostridium difficile From Stool Samples.

BACKGROUND: The aim of this study was to develop and validate a multiplex real-time PCR assay for simultaneous identification and toxigenic type characterization of Clostridium difficile. METHODS: The multiplex real-time PCR assay targeted and simultaneously detected triose phosphate isomerase (tpi) and binary toxin (cdtA) genes, and toxin A (tcdA) and B (tcdB) genes in the first and sec tubes, respectively. The results of multiplex real-time PCR were compared to those of the BD GeneOhm Cdiff assay, targeting the tcdB gene alone. The toxigenic culture was used as the reference, where toxin genes were detected by multiplex real-time PCR. RESULTS: A total of 351 stool samples from consecutive patients were included in the study. Fifty-five stool samples (15.6%) were determined to be positive for the presence of C. difficile by using multiplex real-time PCR. Of these, 48 (87.2%) were toxigenic (46 tcdA and tcdB-positive, two positive for only tcdB) and 11 (22.9%) were cdtA-positive. The sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) of the multiplex real-time PCR compared with the toxigenic culture were 95.6%, 98.6%, 91.6%, and 99.3%, respectively. The analytical sensitivity of the multiplex real-time PCR assay was determined to be 10(3) colony forming unit (CFU)/g spiked stool sample and 0.0625 pg genomic DNA from culture. Analytical specificity determined by using 15 enteric and non-clostridial reference strains was 100%. CONCLUSIONS: The multiplex real-time PCR assay accurately detected C. difficile isolates from diarrheal stool samples and characterized its toxin genes in a single PCR run.

Preservative solution for skeletal muscle biopsy samples.

CONTEXT: Muscle biopsy samples must be frozen with liquid nitrogen immediately after excision and maintained at -80°C until analysis. Because of this requirement for tissue processing, patients with neuromuscular diseases often have to travel to centers with on-site muscle pathology laboratories for muscle biopsy sample excision to ensure that samples are properly preserved. AIM: Here, we developed a preservative solution and examined its protectiveness on striated muscle tissues for a minimum of the length of time that would be required to reach a specific muscle pathology laboratory. MATERIALS AND METHODS: A preservative solution called Kurt-Ozcan (KO) solution was prepared. Eight healthy Sprague-Dawley rats were sacrificed; striated muscle tissue samples were collected and divided into six different groups. Muscle tissue samples were separated into groups for morphological, enzyme histochemical, molecular, and biochemical analysis. STATISTICAL METHOD USED: Chi-square and Kruskal Wallis tests. RESULTS: Samples kept in the KO and University of Wisconsin (UW) solutions exhibited very good morphological scores at 3, 6, and 18 hours, but artificial changes were observed at 24 hours. Similar findings were observed for the evaluated enzyme activities. There were no differences between the control group and the samples kept in the KO or UW solution at 3, 6, and 18 hours for morphological, enzyme histochemical, and biochemical features. The messenger ribonucleic acid (mRNA) of ß-actin gene was protected up to 6 hours in the KO and UW solutions. CONCLUSION: The KO solution protects the morphological, enzyme histochemical, and biochemical features of striated muscle tissue of healthy rats for 18 hours and preserves the mRNA for 6 hours.