Non-fermenting Gram-negative Rods Research Articles

MICROFLORA OF COMBAT WOUNDS OF THE MALE PELVIC ORGANS AND DYSBACTERIOSIS OF THE URINARY SYSTEM

Introduction. Identification of microorganisms that colonize combat wounds and cause wound infection is of primary importance for the subsequent successful treatment of the patient. The resistance of microorganisms to antimicrobial drugs makes the efforts of modern medicine in the fight against infectious agents ineffective. The problem of infertility is closely related to combat injuries, their infection, stress, and neurotic disorders. Aim. Obtaining and summarizing data on microbial colonization of mine-blast wounds of pelvic organs and the microbiome of the genitourinary system of combatants. Materials and methods. 84 smears were taken from 56 wounds of 36 patients with injuries of the pelvic organs who were being treated. 73 patients with injuries were examined for the presence of mycoflora in the urogenital tract. Isolation of pure bacterial cultures was carried out by inoculating the studied material using meat-peptone agar, blood agar, chromogenic agars. For the diagnosis of urogenital or other infections by the PCR method, a scraping from the back wall of the urethra was taken from the patients. Results. Predominant microorganisms in positive cultures of smears were non-fermenting gram-negative rods, which in 28% of cultures belonged to the genus Acinetobacter, in 26% to the genus Pseudomonas. As for associated infections, 20% of them consisted of the genus Acinetobacter, 32% – Enterobacter, 4% – Klebsiella and 29% – Pseudomonas. Gram-positive cocci were isolated in 37% of positive smear cultures. The frequency of isolation of the genus Streptococcus in monoinfection was 2.5%, followed by the genus Clostridium – 2%, Bacillus – 3%, Enterococcus – 4% and Actynomycceas – 4%. In associated infections, the frequency of isolation of the genus Streptococcus was 4%, followed by the genus Clostridium – 2%, Bacillus – 4%, Enterococcus – 3% and Actynomycceas – 5%. When analyzing the microflora of the genitourinary system, it was found that the priority role belongs to the combined infection, when there are associations of specific pathogens such as Ureaplasma spp., Mycoplasma spp., Chlamidia spp., Neisseria gonorrhoeae, Trichomonas vaginalis, Streptococcus spp., Enterococcus faecalis, which is 80% of the entire microbiome. Conclusions. Acinetobacter baumanii and Klebsiella pneumoniae are the dominant microflora complicating the course of combat wounds during almost two years of Russia's full-scale war against Ukraine. Probably, the duration of hostilities, the large number of wounded, and the forced mass unsystematic use of various antibiotics lead to rapid changes in the spectrum of pathogens of combat wounds. Combat wounds and their infection, stress, and nervous disorders lead to an imbalance of microflora, in particular microflora of the genitourinary system, which can be one of the causes of infertility. Chlamydia and Ureaplasma are the most common microorganisms that colonize the urogenital tract of men injured as a result of hostilities.

Complete sequence of carbapenem-resistant Ralstonia mannitolilytica clinical isolate co-producing novel class D β-lactamase OXA-1176 and OXA-1177 in Japan.

In 2020, the Ralstonia mannitolilytica strain JARB-RN-0044 was isolated from a midstream urine sample of an elderly hospitalized patient in Japan and was highly resistant to carbapenem (i.e., imipenem, meropenem, and doripenem). Whole-genome sequencing revealed that the complete genome consists of two replicons, a 3.5-Mb chromosome and a 1.5-Mb large non-chromosomal replicon which has not been reported in R. mannitolilytica, and referred to as the "megaplasmid" in this study based on Cluster of Orthologous Group of proteins functional analysis. The strain JARB-RN-0044 harbored two novel OXA-60 and OXA-22 family class D β-lactamase genes blaOXA-1176 and blaOXA-1177 on the megaplasmid. Cloning experiments indicated that Escherichia coli recombinant clone expressing blaOXA-1176 gene showed increased minimum inhibitory concentrations (MICs) of imipenem, meropenem, and doripenem, indicating that blaOXA-1176 gene encodes carbapenemase. In contrast, E. coli recombinant clone expressing blaOXA-1177 gene showed increased MICs of piperacillin and cefazolin, but not of carbapenem. Interestingly, the 44.6 kb putative prophage region containing genes encoding phage integrase, terminase, head and tail protein was identified in the downstream region of blaOXA-1176 gene, and comparative analysis with some previously reported R. mannitolilytica isolates revealed that the prophage region was unique to strain JARB-RN-0044. The existence of a highly carbapenem-resistant R. mannitolilytica isolate may raise human health concerns in Japan, where the population is rapidly aging.IMPORTANCERalstonia mannitolilytica is an aerobic non-fermenting Gram-negative rod commonly found in aquatic environments and soil. The bacteria can occasionally cause severe hospital-acquired bloodstream infections in immunocompromised patients and it has been recently recognized as an emerging opportunistic human pathogen. Furthermore, some R. mannitolilytica isolates are resistant to various antimicrobial agents, including β-lactams and aminoglycosides, making antimicrobial therapy challenging and clinically problematic. However, clinical awareness of this pathogen is limited. To our knowledge, in Japan, there has been only one report of a carbapenem-resistant R. mannitolilytica clinical isolate from urine by Suzuki et al. in 2015. In this study, whole-genome sequencing analysis revealed the presence and genetic context of novel blaOXA-1176 and blaOXA-1177 genes on the 1.5 Mb megaplasmid from highly carbapenem-resistant R. mannitolilytica isolate and characterized the overall distribution of functional genes in the chromosome and megaplasmid. Our findings highlight the importance of further attention to R. mannitolilytica isolate in clinical settings.

Bacterial Community- and Hospital-Acquired Pneumonia in Patients with Critical COVID-19-A Prospective Monocentric Cohort Study.

The impact of bacterial pneumonia on patients with COVID-19 infection remains unclear. This prospective observational monocentric cohort study aims to determine the incidence of bacterial community- and hospital-acquired pneumonia (CAP and HAP) and its effect on mortality in critically ill COVID-19 patients admitted to the intensive care unit (ICU) at University Hospital Olomouc between 1 November 2020 and 31 December 2022. The secondary objectives of this study include identifying the bacterial etiology of CAP and HAP and exploring the capabilities of diagnostic tools, with a focus on inflammatory biomarkers. Data were collected from the electronic information hospital system, encompassing biomarkers, microbiological findings, and daily visit records, and subsequently evaluated by ICU physicians and clinical microbiologists. Out of 171 patients suffering from critical COVID-19, 46 (27%) had CAP, while 78 (46%) developed HAP. Critically ill COVID-19 patients who experienced bacterial CAP and HAP exhibited higher mortality compared to COVID-19 patients without any bacterial infection, with rates of 38% and 56% versus 11%, respectively. In CAP, the most frequent causative agents were chlamydophila and mycoplasma; Enterobacterales, which were multidrug-resistant in 71% of cases; Gram-negative non-fermenting rods; and Staphylococcus aureus. Notably, no strains of Streptococcus pneumoniae were detected, and only a single strain each of Haemophilus influenzae and Moraxella catarrhalis was isolated. The most frequent etiologic agents causing HAP were Enterobacterales and Gram-negative non-fermenting rods. Based on the presented results, commonly used biochemical markers demonstrated poor predictive and diagnostic accuracy. To confirm the diagnosis of bacterial CAP in our patient cohort, it was necessary to assess the initial values of inflammatory markers (particularly procalcitonin), consider clinical signs indicative of bacterial infection, and/or rely on positive microbiological findings. For HAP diagnostics, it was appropriate to conduct regular detailed clinical examinations (with a focus on evaluating respiratory functions) and closely monitor the dynamics of inflammatory markers (preferably Interleukin-6).

Triple Gram-negative bacterial endophthalmitis following intravitreal injection

PurposeTo describe a puzzling case of endophthalmitis caused by three unusual bacteria after intravitreal injection, its outcome, and underlying questions.FindingsA 70-year-old female patient was diagnosed with acute endophthalmitis following intravitreal aflibercept injection for age-related macular degeneration. A standard tap and inject procedure was performed. Microbiological analyses on the anterior chamber and vitreous samples yielded the presence of three non-fermenting Gram-negative rods: Pseudomonas stutzeri, Stenotrophomonas maltophilia, and Ochrobactrum anthropi. The outcome was favorable after intravitreal injections of vancomycin and ceftazidime, with an almost complete recovery of the visual acuity to its baseline level. No potential source of infection was identified.ConclusionEndophthalmitis following intravitreal injection can be caused by a wide variety of bacteria, including some rare Gram-negative species. They can sometimes co-exist in a single patient, but their virulence may vary greatly. Due to the variable antibiotic susceptibility and frequent multiresistance associated with non-fermenting Gram-negative rods, a prompt microbiological approach is required. Favorable outcome can be achieved with standard management.

Evaluation of In vitro Efficacy of Meropenem/Colistin and Meropenem/Fosfomycin Combinations on Multidrug Resistant Gram-Negative Bacilli

The rate of extensively drug-resistant and pan-resistant gram-negative rods isolated as infectious agents is increasing around the world and in Türkiye. One of the important options in the treatment of these infections is the combined use of antibiotics. Therefore, the aim of this study was to investigate the in vitro effect of meropenem/colistin and meropenem/fosfomycin combinations on carbapenem-resistant gram-negative bacilli isolated as infectious agents. Escherichia coli (n= 6), Klebsiella pneumoniae (n= 10), Pseudomonas aeruginosa (n= 5), and Acinetobacter baumannii (n= 6) isolates were recovered from blood and tracheal aspirate samples of patients hospitalized in our hospital's intensive care unit were included in the study. In the first stage of the combination study, minimal inhibitory concentrations (MIC) were investigated by broth microdilution for meropenem and colistin, and agar dilution methods for fosfomycin. In the second stage of the study, synergy, partial synergy, indifference, and antagonistic effects were investigated with the checkerboard method for the meropenem/colistin combination and the agar dilution method for the meropenem/fosfomycin combination. The checkerboard results were interpreted as follows: fractional inhibitory concentration index (FICI) values ≤ 0.5 synergy, < 0.5-≤ 1 partial synergy, > 1-≤ 4 indifference and FIC values of > 4 antagonism. MIC values obtained in the study were interpreted according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria. Of the 27 isolates studied with the broth microdilution method, 63% were found to be colistin-resistant and 37% susceptible. The MIC values of fosfomycin against Enterobacterales group bacteria were found to be in the range of 2-2048 mg/L. Two of the six E.coli isolates and nine of the 10 K.pneumoniae isolates were found to be resistant to fosfomycin (IV). The MIC values of ≥ 128 mg/L were found in all 11 non-fermentative gram-negative rods with intrinsic resistance to fosfomycin. In the combination of meropenem/ colistin, synergy and partial synergy were observed in 11 (40.7%) of 27 isolates, an indifference effect was observed in 13 (48.2%), and antagonistic effects were observed in three (11.1%) of the isolates. The synergy and partial synergy effects of this combination were 37.5% for Enterobacterales group bacteria, 50% for E.coli, and 30% for K.pneumoniae. Regarding the 11 non-fermentative gram-negative rods included in the study, 83.3% synergy and partial synergy was found in A.baumannii for the meropenem/colistin combination, while no synergy and partial synergistic effect was found in P.aeruginosa. Meropenem/fosfomycin synergy and partial synergy effects were 83.3% (5/6) for E.coli, 100% (8/8) for K.pneumoniae, 100% (6/6) for A.baumannii, and 25% (1/4) for P.aeruginosa. In all of the isolates studied, meropenem/fosfomycin combination was found to be more effective than the meropenem/colistin combination. It would be meaningful to support these data obtained in vitro with clinical efficacy results to be obtained as a result of the application of antibiotics in vivo, taking into account the pharmacokinetic and pharmacodynamic properties of the antibiotics used in this study.

Growth of Gram-Negative Bacteria in Antiseptics, Disinfectants and Hand Hygiene Products in Two Tertiary Care Hospitals in West Africa-A Cross-Sectional Survey.

Antiseptics, disinfectants, and hand hygiene products can act as reservoirs of Gram-negative bacteria causing healthcare-associated infections. This problem is rarely documented in low- and middle-income countries, particularly in sub-Saharan Africa. In a cross-sectional survey, we assessed the bacterial contamination of antiseptics, disinfectants, and hand hygiene products in two university hospitals in Burkina Faso and Benin. During ward visits and staff interviews, in-use products were cultured for the presence of Gram-negative bacteria. The growth of Gram-negative bacteria was absent or rare in alcohol-based products, povidone iodine, and Dakin solution. Contamination was highest (73.9% (51/69)) for liquid soap products (versus antiseptic/disinfectants (4.5%, 7/157) (p < 0.0001)), mostly used in high-risk areas and associated with high total bacterial counts (>10,000 colony-forming units/mL). Contaminating flora (105 isolates) included Enterobacterales and the Vibrio non-cholerae/Aeromonas group (17.1%) and non-fermentative Gram-negative rods (82.8%). Multidrug resistance was present among 9/16 Enterobacterales (Klebsiella and Enterobacter spp.) and 3/12 Acinetobacter spp., including carbapenem resistance (Acinetobacter baumannii: NDM, Pseudomonas stutzeri: VIM). The risk factors for contamination included the type of product (cleaning grade and in-house prepared liquid soap), use of recycled disposable containers and soft drink bottles, absence of labeling, topping-up of containers, dilution with tap water (pharmacy and ward), and poor-quality management (procurement, stock management, expiry dates, and period after opening).

Rarely Encountered Gram-Negative Rods and Lung Transplant Recipients: A Narrative Review.

The respiratory tract of lung transplant recipients (LTR) is likely to be colonized with non-fermentative Gram-negative rods. As a consequence of the improvements in molecular sequencing and taxonomy, an increasing number of bacterial species have been described. We performed a review of the literature of bacterial infections in LTR involving non-fermentative Gram-negative rods with exclusion of Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Achromobacter spp. and Burkholderia spp. Overall, non-fermenting GNR were recovered from 17 LTR involving the following genera: Acetobacter, Bordetella, Chryseobacterium, Elizabethkinga, Inquilinus, and Pandoraea. We then discuss the issues raised by these bacteria, including detection and identification, antimicrobial resistance, pathogenesis, and cross-transmission.

Piometra em cadela de 10 meses: Relato de caso

Pyometra is a potentially fatal infectious pathology that affects the endometrium of female dogs, characterized by the accumulation of pus in the uterine lumen. In general, this pathology occurs in the period of diestrus, due to the ascending bacterial infection that finds a favorable environment for its multiplication in the endometrium that has suffered cystic hyperplasia as a result of the cumulative and prolonged stimulus of female hormones. Normally, it does not have a racial predisposition and affects more middle-aged and elderly animals, from the 4th estrous cycle onwards. Young animals rarely present this pathology and, when it occurs, it is usually associated with the use of exogenous progestogens. The objective of this work is to report the case of a female English Bulldog, 10 months old, who did not use exogenous progestogens, diagnosed with pyometra. The patient was attended to by the Veterinary Hospital of the Federal Rural University of Rio de Janeiro with a mucohemorrhagic vulvar discharge for 24 hours. According to the tutor, the bitch had presented her first heat 13 days before the appointment. In the general physical examination, the patient presented clinical parameters within normal limits, with the exception of temperature (fever), respiratory rate (tachypnea), heart rate (tachycardia), and blood lactate (increased). Due to the presence of systemic inflammatory response syndrome (tachypnea, tachycardia and fever) associated with a possible infectious focus, a complete blood count and renal and hepatic serum biochemistry were requested. In the hemogram, neutrophilic leukocytosis was evaluated, indicating an inflammatory/infectious process and, in the serum biochemistry, hepatic dysfunction was observed. Abdominal ultrasonography was also performed to assess the presence of anechoic content within the uterine horns, suggestive of pyometra. The patient was then referred to surgery for an ovariohysterectomy where the infectious focus was removed. Then, sterile uterine material was collected for culture and antibiogram, obtaining a positive result for two types of bacteria, Streptococcus sp and non-fermenting Gram-negative Rod. Antibiotics, non-steroidal anti-inflammatory drugs and analgesics were prescribed postoperatively, in addition to daily bandage, surgical clothing and protective collar. There were no intercurrences in the trans or postoperative period of the patient, who had no recurrence of clinical signs, and was discharged 10 days after surgery.

Bacterial Contamination of Antiseptics, Disinfectants and Hand Hygiene Products in Healthcare Facilities in High-Income Countries: A Scoping Review

This scoping review addresses bacterial contamination of antiseptics, low-level disinfectants, and hand hygiene products in healthcare settings in high-income countries. Over 70 years, 114 articles were found: 68 outbreaks, 13 pseudo-outbreaks and 33 cross-sectional surveys. Outbreaks affected median 29 (1–151) patients, extended for 26 (1–156) weeks and had a case fatality of 0.0% (0.0–60.0%). Most (72.8%) (pseudo-)outbreaks were caused by water-based chlorhexidine (CHG), quaternary ammonium compounds (QUAT) and the combination CHG–QUAT. Contaminating bacteria were nonfermentative Gram-negative rods (87.6% (pseudo-)outbreaks), mainly Burkholderia cepacia, Pseudomonas aeruginosa and Achromobacter spp.) and Enterobacterales (29.6%, 24/81), mostly Serratia spp.). Risk factors were at the level of the bacteria (natural resistance to CHG and QUAT), containers (design and functioning, presence of cork and cotton, biofilm formation), preparation (nonsterile water, overdilution) and practices (too long expiry dates, inappropriate container reprocessing, topping up of containers and deviation from procedures). Transmission occurred through direct contact (antiseptics), contact with semicritical items (disinfectants) and were handborne (soaps). During recent decades, reports of soap contaminated with Enterobacterales emerged and nationwide outbreaks of intrinsically contaminated CHG occurred. Outstanding issues comprise intrinsic contamination, implementation of antiseptic stewardship, the role of unit doses and sterile products, transmission studies, biofilm control and understanding healthcare providers’ perceptions.

Bacterial Contamination of Antiseptics, Disinfectants, and Hand Hygiene Products Used in Healthcare Settings in Low- and Middle-Income Countries—A Systematic Review

We conducted a systematic review of healthcare-associated outbreaks and cross-sectional surveys related to the contamination of antiseptics, disinfectants, and hand hygiene products in healthcare settings in low- and middle-income countries (PROSPERO CRD42021266271). Risk of bias was assessed by selected items of the ORION and MICRO checklists. From 1977 onwards, 13 outbreaks and 25 cross-sectional surveys were found: 20 from Asia and 13 from Africa. Products most associated with outbreaks were water-based chlorhexidine, chlorhexidine-quaternary ammonium compound combinations (7/13), and liquid soap products (4/13). Enterobacterales (including multidrug-resistant Enterobacter cloacae, Klebsiella pneumoniae, and Serratia marcescens) and non-fermentative Gram-negative rods were found in 5 and 7 outbreaks and in 34.1% and 42.6% of 164 isolates, respectively, from cross-sectional surveys. Risk factors included preparation (place, utensils, or tap water high and incorrect dilutions), containers (reused, recycled, or inadequate reprocessing), and practices (topping-up or too long use). Potential biases were microbiological methods (neutralizers) and incomplete description of products’ identity, selection, and denominators. External validity was compromised by low representativeness for remote rural settings and low-income countries in sub-Saharan Africa. Outstanding issues were water quality, biofilm control, field-adapted containers and reprocessing, in-country production, healthcare providers’ practices, and the role of bar soap. A list of “best practices” to mitigate product contamination was compiled.

Identifying patients at high risk for multidrug-resistant organisms after hospitalization abroad.

We quantified the percentage of multidrug-resistant organism (MDRO) carriers among repatriated patients. We identified factors associated with MDRO carriage, and we evaluated the yield of MDRO detection per screened body site. Retrospective cohort study. A tertiary-care center in Switzerland. Adult patients after a stay in a healthcare institution abroad. Patients were screened for MDRO carriage. Standard sites, including nose and throat, groins, and (since mid-2018) rectum, and risk-based sites (wounds, urine, tracheal secretion) were sampled. MDROs were defined as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), extended-spectrum β-lactamase (ESBL)- and carbapenemase-producing Enterobacterales (CPE), multidrug-resistant (MDR) Enterobacterales, and MDR nonfermenting gram-negative rods. Risk factors for MDRO carriage were assessed using multivariate logistic regression. Between May 2017 and April 2019, 438 patients were screened and 107 (24.4%) tested positive for an MDRO, predominantly ESBL-producing and MDR Enterobacterales. Risk factors for MDRO colonization were the length of stay in hospital abroad, antibiotic treatment with 'Watch' and 'Reserve' antibiotics, and region of hospitalization abroad. Rectal swabs had the highest yield for detecting patients with MDR intestinal bacteria, but nose/throat and groins,or wound samples were more sensitive for MRSA or nonfermenting gram-negative organisms, respectively. We identified risk factors for MDRO carriage and body sites with the highest yield for a specific MDRO, which might help to target screening and isolation and reduce screening costs.

Impact of Persistent Multidrug-Resistant Gram-Negative Bacteremia on Clinical Outcome and Mortality

The clinical aspects of persistent bacteremia (PB) caused by gram-negative rods (GNRs) in terms of antimicrobial resistance (AMR) and PB clearance status are unclear. This secondary analysis of a retrospective cohort study investigated differences in PB caused by Enterobacterales and glucose non-fermentative GNRs (NF-GNRs) based on AMR and PB clearance. We retrospectively surveyed medical records at Tohoku University Hospital. Patients for whom blood cultures were performed between January 2012 and December 2021 were recruited. PB cases were grouped based on AMR and PB clearance; the characteristics of PB due to each bacterial pathogen were examined. The main outcome variable was mortality. The late (30-90-day) mortality rate was significantly higher in the multidrug-resistant (MDR) group than in the non-MDR group for Enterobacterales. However, no significant difference was noted in mortality rates between NF-GNRs with and without AMR. Mortality rates tended to be higher in the non-PB-clearance group than in the clearance group for both Enterobacterales and NF-GNRs. Since the mortality rate was higher in the MDR group in the case of Enterobacterales PB, more careful management is necessary for this condition. Follow-up blood cultures and confirming the clearance of PB are useful for improving the survival rate.

A systematic analysis of nosocomial outbreaks of nosocomial infections after gastrointestinal endoscopy

Esophagogastroduodenoscopy (EGD), endoscopic retrograde cholangiopancreatography (ERCP) and colonoscopy (CLN) come with a potential risk of pathogen transmission. Unfortunately, up to now data on the causes and the distribution of pathogens is rather sparse.We performed a systematic review of the medical literature using the Worldwide Outbreak Database, the PubMed, and Embase. We then checked so-retrieved articles for potential sources of the outbreak, the spectrum of pathogens, the attack rates, mortality and infection control measures.In total 73 outbreaks (EGD: 24, ERCP: 42; CLN: 7) got included. The corresponding attack rates were 3.5%, 7.1% and 12.8% and mortality rates were 6.3%, 12.7% and 10.0% respectively. EGD was highly associated with transmission of enterobacteria including a large proportion of multi-drug resistant strains. ERCP led primarily to transmission of non-fermenting gram-negative rods. The most frequent cause was human failure during reprocessing regardless of the type of endoscope.Staff working in the field of endoscopy should always be aware of the possibility of pathogen transmission in order to detect and terminate those events at the early most time point. Furthermore, proper ongoing education of staff involved in the reprocessing and maintenance of endoscopes is crucial. Single-use devices may be an alternative option and lower the risk of pathogen transmission, but on the downside may also increase costs and waste.

The use of UV-C radiation for terminal disinfection of pathogenic Gram-negative rods: a pilot study.

In this controlled study, we found that exposure to ultraviolet-C (UV-C) radiation was able to arrest the growth of selected pathogenic enteric and nonfermenting Gram-negative rods. Further studies are needed to confirm the clinical efficacy and determine optimal implementation strategies for utilizing UV-C terminal disinfection.

Presence of Gram-negative bacteria and Staphylococcus aureus on the skin of blood donors in the Democratic Republic of the Congo.

Skin bacteria may contaminate blood products but few data are available on sub-Saharan Africa (sSA). We assessed the presence of Gram-negative bacteria and Staphylococcus aureus on blood donor skin and evaluated skin antisepsis in the Democratic Republic of the Congo (DRC). Among blood donors at the National Blood Transfusion Center (NBTC) and at a rural hospital, the antecubital fossa skin of the non-disinfected arm (not used for blood collection) was swabbed (25cm2 surface) and cultured for total and Gram-negative bacterial counts. Bacteria were identified with MALDI-TOF and tested for antibiotic susceptibility by disk diffusion. For evaluation of the NBTC antisepsis procedure (i.e., ethanol 70%), the culture results of the disinfected arm (used for blood collection) were compared with those of the non-disinfected arm. Median total bacterial counts on 161 studied non-disinfected arms were 1065 Colony-Forming Units (CFU) per 25 cm2 , with 43.8% (70/160) of blood donors growing Gram-negative bacteria and 3.8% (6/159) Staphylococcus aureus (2/6 methicillin-resistant). Non-fermentative Gram-negative rods predominated (74/93 isolates, majority Pseudomonas spp., Acinetobacter spp.). Enterobacterales comprised 19/93 isolates (mostly Pantoea spp. and Enterobacter spp.), 5/19 were multidrug-resistant. In only two cases (1.9%, 2/108) the NBTC antisepsis procedure met the acceptance criterion of ≤2CFU/25 cm2 . Skin bacterial counts and species among blood donors in DRC were similar to previously studied Caucasian populations, including cold-tolerating species and bacteria previously described in transfusion reactions. Prevention of contamination (e.g., antisepsis) needs further evaluation and customization to sSA.

Carbapenem-Resistant Gram-Negative Fermenting and Non-Fermenting Rods Isolated from Hospital Patients in Poland-What Are They Susceptible to?

Gram-negative fermenting and non-fermenting bacteria are important etiological factors of nosocomial and community infections, especially those that produce carbapenemases. Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa are the most frequently-detected carbapenemase-producing microorganisms. The predominant type of resistance is metallo-β-lactamase (MBL). These bacteria are predominantly isolated from bronchial alveolar lavage, urine, and blood. Carbapenemase-producing Enterobacterales (CPE) strains are always multi-drug-resistant. This significantly limits the treatment options for this type of infection, extends the time of patient hospitalization, and increases the risk of a more severe and complicated disease course. Preventing the transmission of these microorganisms should be a major public health initiative. New antibiotics and treatment regimens offer hope against these infections.

Roles of SmeYZ, SbiAB, and SmeDEF Efflux Systems in Iron Homeostasis of Stenotrophomonas maltophilia.

ABSTRACTStenotrophomonas maltophilia, a nonfermenting Gram-negative rod, is frequently isolated from the environment and is emerging as a multidrug-resistant global opportunistic pathogen. S. maltophilia harbors eight RND-type efflux pumps that contribute to multidrug resistance and physiological functions. Among the eight efflux pumps, SmeYZ pump is constitutively highly expressed. In our previous study, we demonstrated that loss-of-function of the SmeYZ pump results in pleiotropic phenotypes, including abolished swimming motility, decreased secreted protease activity, and compromised tolerance to oxidative stress and antibiotics. In this study, we attempted to elucidate the underlying mechanisms responsible for ΔsmeYZ-mediated pleiotropic phenotypes. RNA-seq transcriptome analysis and subsequent confirmation with qRT-PCR revealed that smeYZ mutant experienced an iron starvation response because the genes involved in the synthesis and uptake of stenobactin, the sole siderophore of S. maltophilia, were significantly upregulated. We further verified that smeYZ mutant had low intracellular iron levels via inductively coupled plasma mass spectrometry (ICP-MS). Also, KJΔYZ was more sensitive to 2,2′-dipyridyl (DIP), a ferrous iron chelator, in comparison with the wild type. The contribution of SmeYZ, SmeDEF, and SbiAB pumps to stenobactin secretion was suggested by qRT-PCR and further verified by Chrome Azurol S (CAS) activity, iron source utilization, and cell viability assays. We also demonstrated that loss-of-function of SmeYZ led to the compensatory upregulation of SbiAB and SmeDEF pumps for stenobactin secretion. The overexpression of the SbiAB pump resulted in a reduction in intracellular iron levels, which may be the key factor responsible for the ΔsmeYZ-mediated pleiotropic phenotypes, except for antibiotic extrusion.IMPORTANCE Efflux pumps display high efficiency of drug extrusion, which underlies their roles in multidrug resistance. In addition, efflux pumps have physiological functions, and their expression is tightly regulated by various environmental and physiological signals. Functional redundancy of efflux pumps is commonly observed, and mutual regulation occurs among these functionally redundant pumps in a bacterium. Stenotrophomonas maltophilia is an opportunistic pathogen that shows intrinsic multi-drug resistance. In this study, we demonstrated that SmeYZ, SbiAB, and SmeDEF efflux pumps of S. maltophilia display functional redundancy in siderophore secretion. Inactivation of smeYZ led to the upregulation of smeDEF and sbiAB. Unexpectedly, sbiAB overexpression resulted in the reduction of intracellular iron levels, which led to pleiotropic defects in smeYZ mutant. This study demonstrates a previously unidentified connection between efflux pumps, siderophore secretion, and intracellular iron levels in S. maltophilia.

Microbiology and clinical outcomes of central venous catheter-related blood stream infections in patients on maintenance hemodialysis

Central venous catheter-related blood stream infection (CRBSI) is a major cause of morbidity and mortality in patients on maintenance hemodialysis. The objective of the study was to assess the microbiology and clinical outcomes of CRBSI in patients on maintenance hemodialysis. This was a retrospective observational study of all the patients with Stage 5 chronic kidney disease on maintenance hemodialysis at Pushpagiri Medical College Hospital who developed CRBSI between 1st January 2019 and 31st December 2020. Out of the 105 CRBSI patients included in the study, 75% had diabetes mellitus while 95% had hypertension. The median time gap between central venous catheter (CVC) placement and CRBSI was found to be 22 days with a range of 3 days to 150 days. Fever was the most common clinical presentation of CRBSI while a few patients presented with encephalopathy and septic shock. The most commonly used empirical antibiotic was intravenous Cephalosporins. The most common micro-organism grown in culture was non-fermenting gram-negative rods (22.84%) followed by Staphylococcus aureus and Bacillus species. The success rate which was defined as resolution of symptoms without the need of modifying the antibiotic or change of CVC was 34.28%. 31% of patients required modification of antibiotic while 56.18% required change of CVC. Complications developed in 10.47% of patients, the most common being encephalopathy followed by septic shock. 5(4.7%) patients succumbed to complications while all others recovered completely. While treatment of CRBSI with empirical intravenous antibiotics alone was successful in only about one-third of the patients, culture-guided modification of antibiotic regimen with or without change of CVC, led to clinical improvement in the majority of cases.

An Application of Imipenem Discs or P. aeruginosa ATCC 27853 Reference Strain Increases Sensitivity of Carbapenem Inactivation Method for Non-Fermenting Gram-Negative Bacteria

Non-fermenting Gram-negative rods are one of the most commonly isolated bacteria from human infections. These microorganisms are typically opportunistic pathogens that pose a serious threat to public health due to possibility of transmission in the human population. Resistance to beta-lactams, due to carbapenemases synthesis, is one of the most important antimicrobial resistance mechanisms amongst them. The aim of this study was to evaluate the usefulness of the Carbapenem Inactivation Method (CIM), and its modifications, for the detection of carbapenemase activity amongst non-fermenting Gram-negative rods. This research involved 81 strains of Gram-negative rods. Of the tested strains, 55 (67.9%) synthesized carbapenemases. For non-fermenting rods, 100% sensitivity and specificity was obtained in the version of the CIM test using imipenem discs and E. coli ATCC 25922 strain. The CIM test allows for differentiation of carbapenems resistance mechanisms resulting from carbapenemase synthesis from other resistance types. It is a reliable diagnostic method for the detection of carbapenemase activity amongst non-fermenting Gram-negative rods. Application of imipenem discs and P. aeruginosa ATCC 27853 reference strain increases CIM results sensitivity, while imipenem discs and E. coli ATCC 25922 strain use maintains full precision of the test for non-fermenting rods.

SPECIFIC ASPECTS IN TREATMENT OF SUPPURATIVE-INFLAMMATORY COMPLICATIONS IN GUNSHOT WOUNDS OF EXTREMITIES

Summary. The aim of the study was to present an argument for treatment algorithm of patients with extremity gunshot injuries complicated by suppurative inflammation.&#x0D; Materials and research methods. Examination and treatment of 163 patients with gunshot wounds of the extremities were performed. All the wounded were divided into 3 study groups. The patients of group 1 underwent conventional treatment of gunshot wounds. In group 2, negative pressure wound therapy was used. Wounded patients of group 3 received vacuum-assisted therapy supplemented by the proposed scheme of counter-drainage and flow-through flushing irrigation of wounds with antiseptic solutions of 0.02 % decamethoxine and 3 % hydrogen peroxide. Bacteriological study of wound exudate was carried out, and sensitivity of microorganisms to antibiotics was determined.&#x0D; Results and its discussion. Wound microbiology analysis in victims of blast and mine-blast injuries demonstrated predominance of gram-negative bacteria in wound microbiocenosis — Acinetobacter spp. (53 % of cases) and Pseudomonas spp. (15 % of cases). Gram-positive cocci were isolated in 22.2 % of cases. Sensitivity study of nonfermentative gram-negative rods demonstrated them to have high level of resistance to most antibacterial agents. All strains of Acinetobacter and Pseudomonas spp. were sensitive to polymyxin B and colistin but resistant to inhibitor-protected and -unprotected amino penicillin.&#x0D; Beneficial effect of vacuum therapy in patients of groups 2 and 3 was evidenced by significantly reduced time of wound healing and hospital stay. The use of suggested mixture of antiseptics resulted in decrease of inflammation in 94.45 % and 88.89 % of patients in groups 3 and 2, respectively. Besides, in group 3, duration of hydration phase in wound healing process decreased to 5.7 days. The period of complete wound healing was shorter by 2.5 days, and hospital stay decreased from 14.97 to 10.8 days.&#x0D; Conclusions. Thus, predominance of gram-negative microorganisms in gunshot wounds as well as their high resistance to antibiotics should be considered when undertaking empirical antibiotic therapy in wounded patients. The proposed treatment algorithm involving negative pressure wound therapy supplemented with counter-drainage and flow-through flushing irrigation with a mixture of suggested antiseptics proved to be highly efficient in patients with extremity gunshot injuries complicated by suppurative inflammation.