Lactate level is an independent predictor of mortality in patients with hematologic malignancy receiving urgent chemotherapy in intensive care unit.

BACKGROUND: Intensive care unit (ICU) survival of cancer patients has improved. Urgent chemotherapy has become feasible in critically ill patients with specific organ dysfunction due to hematological malignancies. OBJECTIVE: The aim of the study was to assess ICU mortality rates and the factors associated with mortality in patients with hematologic malignancies receiving urgent chemotherapy in the ICU. METHODS: We retrospectively included all patients admitted to the ICU who received chemotherapy due to hematologic malignancy in 2012-2022. RESULTS: Of the 129 patients undergoing chemotherapy in the ICU, 50 (38.7 %) died during the ICU follow-up. The following conditions were significantly more common among nonsurvivors: presence of infection at the time of ICU admission (p < 0.001), the requirement for mechanical ventilation during ICU stay (p < 0.001), the need for noninvasive mechanical ventilation during ICU stay (p = 0.014), vasopressor support (p < 0.001), and sepsis (p < 0.001). Logistic regression analysis revealed that among laboratory parameters on ICU admission, lactate (p = 0.008), albumin (p = 0.022), C-reactive protein (p = 0.046), baseline sequential organ failure assessment (SOFA) score (p < 0.001), newly developed heart failure (p = 0.006), and the requirement for vasopressor agents during ICU stay (p < 0.001) significantly influenced the risk of mortality in the univariate analysis. The multivariate analysis revealed lactate levels (p = 0.047) on ICU admission as an independent predictor of mortality. CONCLUSION: The development of heart failure and lactate levels on admission were the main predictors of mortality. Additionally, higher SOFA scores revealed that illness severity was closely associated with mortality. Future studies should focus on strategies to further reduce these risks and achieve the best outcomes for these patients.

Effect of Predator Bacteria Bdellovibrio bacteriovorus on Clinical Pathogens and Biofilms.

Antimicrobial resistance has become one of the most important public health problems of our century. In addition to the spread of resistance, biofilm production also makes the treatment of infections increasingly difficult. Therefore, this study, it was aimed to investigate the effect of the predator bacterium Bdellovibrio bacteriovorus HD100 on various clinical pathogens and their biofilms. A large panel of Gram-positive and negative clinical isolates were included in the study. The double-layer agar method was used to optimize the cultivation of predatory bacteria. The effectiveness of Bdellovibrio bacteriovorus HD 100 on planktonic cells and biofilms, was determined by co-culture and crystal violet staining methods, respectively. The antibiofilm activity was also visualized via scanning electron microscopy. The predator bacteria was found effective against most of the Gram-negative isolates. But it was determined that the lowest activity among these isolates was shown to Pseudomonas aeruginosa and Acinetobacter baumannii. Although it is known that B. bacteriovorus does not predate on Gram-positive isolates, interestingly, Staphylococci species included in this study were found to be inhibited in co-culture studies. As determined in co-culture and biofilm studies, B. bacteriovorus can be used to control both bacterial growth and biofilms in most Gram-negative species. Interestingly, our data also suggest that predatory bacteria may also be effective against Gram-positive bacterial biofilms in addition to Staphylococcus aureus. Although the evaluation of different species of isolates in this study demonstrates the potential of predatory bacteria, the host specificity and the relation of prey and predator need to be demonstrated. Supplementary Information: The online version contains supplementary material available at 10.1007/s12088-023-01071-y.

Investigation of the presence of carbapenemases in carbapenem-resistant Klebsiella pneumoniae strains by MALDI-TOF MS (matrix-assisted laser desorption ionization-time of flight mass spectrometry) and comparison with real-time PCR method.

PURPOSE: We aimed to develop a new procedure for rapid detection of the carbapenemase activity using MALDI-TOF MS, and to determine the sensitivity and specificity of the method. Also, we aimed to determine the distribution of carbapenemase genes among the K.pneumoniae strains isolated in our hospital using real-time PCR. METHOD: Between January 2017-February 2019; K. pneumoniae strains(n = 74) isolated from blood culture samples were included. Klebsiella pneumoniae NCTC 13438 was used as a positive control and Escherichia coli ATCC 25922 as a negative control. First, Imipenem, meropenem, and ertapenem MIC values of strains were determined. Then blaKPC, blaOXA-48, and/or blaNDM genes were investigated with PCR. Carbapenemase activity was investigated in strains with the newly developed method using MALDI-TOF MS. The performance of the new method was evaluated for both the second and fourth hours of the incubation period. RESULTS: While 65 strains were found resistant to tested carbapenems, nine of them were susceptible. Of the 65 resistant strains, 57 had blaOXA-48, 15 had blaNDM, and four had blaKPC genes. BlaOXA-48 and blaNDM genes were detected together in 11 strains. BlaOXA-48, blaNDM, and blaKPC genes were not detected in any of the susceptible strains. The sensitivity and specificity of MALDI-TOF MS at the second hour were 83.1% and 100%, respectively. At the fourth hour, the sensitivity and specificity of MALDI-TOF MS were 100%. No false-positive results were observed. CONCLUSION: The sensitivity of the method at the fourth hour was better than the second hour. The false-negative results observed in the second hour disappeared when the incubation period was extended to 4 h. MALDI-TOF MS which is still under development is a fast, cost-effective, promising method for the detection of carbapenemase activity.

Effects of disinfectants and ciprofloxacin on quorum sensing genes and biofilm of clinical Pseudomonas aeruginosa isolates.

BACKGROUND: Pseudomonas aeruginosa is one of the most virulent bacteria and quorum sensing (QS) genes have an importance on virulence factors such as biofilm that provide resistance against disinfectants and antibiotics. OBJECTIVE: This study aimed to determine the minimum inhibitory concentrations of the disinfectants, to investigate the effects of disinfectants and ciprofloxacin on biofilm production mature biofilm of clinical P. aeruginosa isolates, and it was aimed to investigate the effects of the agents on the expression levels of several QS-related genes in the isolates. METHODS: Minimum inhibitory concentration (MIC) levels of polyhexamethylene biguanide (PHMB), chlorhexidine (CHX), quaternary ammonium compounds (QAC), glutaraldehyde (GLU) and ciprofloxacin (CIP) against clinical P. aeruginosa isolates were evaluated by microdilution method. Effects of the agents on the biofilm producing capacities of clonally unrelated nine strains were investigated by spectrophotometric method. Alterations in the expression of QS-related genes (lasI, lasR, rhlI and rhlR) were investigated by qPCR in three isolates that were CIP-susceptible and strong biofilm producer. RESULTS: According to microdilution method results, three isolates were found as resistant, one isolate was found as intermediate susceptible and five isolates were found as susceptible to CIP, and CHX (7.81-31.25 µg/mL) had the lowest MIC against P. aeruginosa. CHX inhibited biofilm production levels of eight of nine isolates, and GLU and CIP inhibited six of nine isolates in the presence of agents at MIC levels. GLU inhibited the mature biofilm levels of three of nine isolates at MIC and MIC/4 levels and four of nine isolates at MIC/2 levels. Expression levels of QS-related genes were reduced or induced in the presence of different disinfectants. CONCLUSIONS: More efforts are required to decrease the risk of ineffective and low-dose application of disinfectants and antimicrobials against bacteria. Targeting of QS-related genes may be a reasonable strategy for the inhibition of virulence factors in P. aeruginosa.

Quercetin inhibits swarming motility and activates biofilm production of Proteus mirabilis possibly by interacting with central regulators, metabolic status or active pump proteins.

BACKGROUND: Via its virulence factors such as swarm differentiation, biofilm and hemolysin production, urease enzyme, Proteus mirabilis causes urinary tract infections (UTIs), especially in complicated cases. Anti-pathogenic compounds attenuate the virulence of bacteria without showing 'cidal' activity and carry the potential to be used in the prevention and treatment of infectious diseases. PURPOSE: Search for anti-pathogenic effects of quercetin, which is a widely known and biologically active phytochemical, on Proteus mirabilis was the purpose of this study. In this context, the potential inhibitory activity of quercetin on swarming motility and biofilm production of a wild-type strain, P. mirabilis HI4320, was investigated in both phenotypically and genotypically. METHODS: Quercetin's effect on swarming motility was examined on LB agar plates, containing quercetin at various concentrations, by measuring the swarming diameter. The effect on biofilm formation, on the other hand, was analyzed by staining the formed biofilm of the bacterium, exposed to quercetin at various concentrations, with crystal violet and reading spectrophotometrically. Differences in expression levels of selected genes involved in swarming regulation were determined by real-time reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) to evaluate the mechanism of inhibitory action on swarming. Further investigations were carried out repeating swarming assays with the clones that derived from the wild-type strain by a TA system kit for direct one-step cloning and overexpressing the relevant genes. RESULTS: Our study revealed that quercetin inhibited swarming motility while activating biofilm production of P. mirabilis in direct proportion to the dose. Although all selected genes are inhibited in the same manner in liquid medium, and no significant differences could be detected in solid medium as demonstrated by RT-qPCR, experiments repeated with the clones overexpressing flhC (a component of flagellar transcriptional activator), speB (an agmatinase enzyme) and ompF (an outer membrane porin) genes showed that the respective clones could restore swarming, compensating for the inhibitory effect of quercetin. CONCLUSION: Quercetin's inhibitory effect on P. mirabilis swarming was possibly due to interactions with components of swarming regulators, the genes expressing polyamine coding enzymes that trigger swarm differentiation, or active pump proteins.

Antibacterial resistance patterns and incidence of hospital-acquired Staphylococcus aureus bacteremia in a tertiary care educational hospital in Turkey: a perspective from 2001 to 2013

Background/aim: Staphylococcus aureus is an important nosocomial pathogen and a successful antimicrobial-resistance developer. In this study we retrospectively evaluated the resistance patterns and incidence of microbiologically confirmed nosocomial bacteremia (MCNB) related S. aureus strains between 2001 and 2013. Materials and methods: Any patient in whom S. aureus was isolated in at least one set of blood cultures (sent to the bacteriology laboratory 72 h after hospital admission) was considered to have MCNB. Results: The methicillin-resistant S. aureus (MRSA) rate in 2001 was 73.8% whereas it was 36.2% in 2013. When the 2001-2003 and 2011?2013 periods were compared, resistance to oxacillin, levofloxacin, gentamicin, erythromycin, and clindamycin decreased significantly (P < 0.05). When we evaluated the total S. aureus, MRSA, and methicillin-sensitive S. aureus (MSSA) bacteremia rates per 1000 days and 1000 patients, there was an increase in the 2004?2005 period, which was followed by a slight decrease until 2013 (P < 0.05). There was a plateau in MCNB-related S. aureus rates between 2008 and 2011. Conclusion: There was a decrease in overall S. aureus and MRSA bacteremia incidence as well as MRSA rates except for a plateau between 2008 and 2011. This steady decrease in the resistance rates is most probably due to the 2003 budget application and application of antimicrobial stewardship.

[Results of a multicenter study investigating plasmid mediated colistin resistance genes (mcr-1 and mcr-2) in clinical Enterobacteriaceae isolates from Turkey]. / Ülkemizde klinik Enterobacteriaceae izolatlarinda plazmit aracili kolistin direnç genlerini (mcr-1 ve mcr-2) arastiran çok merkezli çalismaya ait sonuçlar.

Colistin is a polymyxin antibiotic which is considered as one of the last line agents against infections due to multidrug resistant or carbapenem resistant gram-negative pathogens. Colistin resistance is associated with chromosomal alterations which can usually cause mutations in genes coding specific two component regulator systems. The first plasmid-mediated colistin resistance gene, mcr-1 was described in Escherichia coli and Klebsiella pneumoniae isolates in December 2015 and followed by another plasmid-mediated colistin resistance gene mcr-2 in 2016. The rapid and interspecies dissemination of plasmid-mediated resistance mechanisms through horizontal gene transfer, have made these genes considerably threatening. After the first reports, although mcr-1/mcr-2 producing Enterobacteriaceae isolates have been reported from many countries, there have been no reports from Turkey. Thus, the aim of this study was to investigate the presence of mcr-1/mcr-2 in clinical Enterobacteriaceae isolates from different parts of our country. A total of 329 Enterobacteriaceae isolates from 22 laboratories were collected which were isolated between March, 2015 and February, 2016. mcr-1/mcr-2 were investigated by polymerase chain reaction during February-March, 2016. Two hundred and seventeen of Klebsiella pneumoniae (66%), 75 of Salmonella spp. (22.8%), 31 of Esherichia coli (9.4%), 3 of Enterobacter cloacae (0.9%), 2 of Klebsiella oxytoca (0.6%) and 1 of Enterobacter aerogenes (0.3%) isolates were included to the study. Agarose gel electrophoresis results of PCR studies have shown expected band sizes for positive control isolates as 309 bp for mcr-1 and 567 bp for mcr-2. However, the presence of mcr-1/mcr-2 genes was not detected among the tested study isolates of Enterobacteriaceae. Although mcr-1/mcr-2 were not detected in our study isolates, it is highly important to understand the mechanism of resistance dissemination and determine the resistant isolates by considering that colistin is a last-line antibiotic against infections of multidrug or carbapenem resistant gram-negative bacteria. Thus, it is suggested that these mechanisms should be followed-up in both clinical and non-clinical (e.g. isolates from food animals, raw meats and environment) isolates of special populations.