blaOXA Genes Research Articles

Prevalence of blaOXA-48 and other carbapenemase encoding genes among carbapenem-resistant Pseudomonas aeruginosa clinical isolates in Egypt.

Resistance to carbapenem, the last line of treatment for gram-negative bacterial infections has been increasing globally and becoming a public health threat. Since integrons may aid in the transmission of resistance genes, the purpose of this study was to detect the frequency of class 1, 2, and 3 integrons as well as carbapenem-resistant genes in clinical isolates of P. aeruginosa that are resistant to carbapenem. This study was carried out on 97 clinical isolates of P. aeruginosa isolated from wound and urine samples. The antimicrobial susceptibility for all isolates was tested by the disc diffusion method. The presence of integrons and carbapenem-resistant genes among carbapenem-resistant P. aeruginosa isolates was evaluated by conventional PCR. The antimicrobial resistance rate among P. aeruginosa clinical isolates was high, with imipenem resistance in 58.8% of the studied isolates. In this study, 86% of the carbapenem-resistant P. aeruginosa isolates carry carbapenemase genes, with blaVIM being the most common gene followed by the blaOXA-48 gene. Class 1 and class 2 integrons were reported in 37 (64.9%) and 10 (17.5%) of the tested carbapenem-resistant P. aeruginosa isolates, respectively. Our data reported a high prevalence of class 1 integrons in carbapenem-resistant P. aeruginosa clinical isolates, suggesting the important role of integrons in carbapenem-resistant gene transfer among such isolates.

Molecular surveillance of A. baumannii in intensive care units: exploration of transmission chains

Abstract Background Multidrug-resistant Acinetobacter baumannii (MDR-Ab) is one of the main causes of healthcare associated infections (HAIs). During the SARS-CoV-2 pandemic there was an increase in MDR-Ab infections, especially in intensive care units (ICUs). This study aimed to assess the potential spread or emergence of specific clusters of MDR-Ab across four different ICUs at the Umberto I teaching hospital of Rome. Methods From January 2020 to January 2022 microbiological surveillance was conducted in four ICUs: two dedicated to COVID-19 patients (ICU-1C, ICU-2C) and two to non-COVID-19 patients (ICU-1R, ICU-2R). The genetic relatedness between A. baumannii isolates was assessed using pulsed-field gel electrophoresis (PFGE). Illumina whole genome sequencing was conducted on 26 representative isolates. Results In total, 178 A. baumannii isolates were obtained from 129 COVID-19 patients and 49 non-COVID-19 patients. The isolates were classified into 17 PFGE pulsotypes, being two major (A, B) and five intermediate (C, D, E, H, Q). Clone A was present in all ICUs, while Clone B was present only in ICU-1C and ICU-2R. Overall, 117 isolates belonged to clone A and exhibited a MDR phenotype; all of them were placed within the international clonal lineage II. All isolates showed carbapenems resistance primarily attributed to the presence of the blaOXA-23 gene, while aminoglycosides resistance observed in almost all isolates was attributed to the presence of the armA gene. Small outbreaks involving intermediate pulsotypes were detected between ICU-1R and ICU-2R, ICU-1C and ICU-2R, ICU-1C and ICU-2C, ICU-1C and ICU-1R. Conclusions The observed outbreaks could be attributed to a decline in attention to normal care practices for the prevention of HAIs during the COVID-19 pandemic, favouring the spread of MDR-Ab. Therefore, it is recommended the strengthen of control measures and the implementation of long-term strategies targeting MDR microorganisms in the ICUs. Key messages • Acinetobacter baumannii was frequently found infecting patients across four different ICUs at the Umberto I teaching hospital of Rome. • Acinetobacter baumanni outbreaks and multidrug resistance were observed. Therefore, the implementation of long-term strategies targeting MDR microorganisms in the ICUs is highly recommended.

THE PREVALENCE OF (OMPA, CSUE) GENES AMONG BIOFILM PRODUCER ACINETOBACTER BAUMANNII ISOLATES

Acinetobacter baumannii is a significant public health problem because it is capable of forming biofilms that may be responsible for the survival of this pathogen in the hospital environment. The aim of this study is to determine the role of (OmpA, CsuE) genes in biofilm production among A. baumannii isolates. A total of 100 clinical isolates of bacteria were collected from a different sources. All isolates were identified by biochemical test, specific selective media (CHROMagar) and polymerase chain reaction by detection presence of (blaOXA51) gene. only 60 isolates were diagnosed as A. baumannii, and to determine the biofilm production capacity two different methods were used Congo red agar method(CRA) and Microtiter plate method (MTP). MTP method result showed 85% of isolates were able to form biofilms, on the other hand, 33.33% of isolates had a biofilm production ability by showing bright black colonies on CRA. Conventional PCR was used to detect the presence of (OmpA, CsuE) genes and the result showed the prevalence of both genes in all isolates were 97%(58/60). It also shows a strong correlation between the presence of these genes and biofilm formation.

Emergence and spread of resistant and biofilm-forming Acinetobacter baumannii in critically ill COVID-19 patients

The COVID-19 pandemic has raised concerns beyond the viral infection itself. Bacterial co-infections, particularly those involving Acinetobacter baumannii, have become a significant worry in critically ill COVID-19 patients. A. baumannii is an opportunistic pathogen that can cause nosocomial infections, especially in patients with compromised immune systems. This study investigated 36 A. baumannii isolates obtained from COVID-19 patients during a concurrent outbreak. The isolates were collected over two years through routine medical requests sent to the Clinical Microbiology laboratory. Identification of the strains was confirmed through biochemical tests, the Phoenix BD® Automated Microbiology System, and MALDI-TOF Mass Spectrometry. The study assessed the antimicrobial sensitivity of the isolates, with a specific focus on resistance to the beta-lactam group as well as aminoglycosides. The presence of specific antibiotic resistance genes (blaOXA-23, -24, -51 and -58, blaKPC, blaSHV, blaIMP, blaVIM, aac(6′)-Ib, ant(3″)-Ia, and aph(3′)-Ia) was investigated using PCR and Sanger DNA sequencing. Biofilm-forming capabilities of the isolates were also evaluated. The findings revealed diverse resistance profiles, with a high prevalence of resistant strains, including resistance to carbapenems. Genetic analysis suggested potential clonal spread of certain strains within the hospital setting. Moreover, a significant proportion of the isolates demonstrated strong biofilm-forming abilities, which can enhance persistence and antibiotic resistance. In conclusion, this study highlights the need for vigilant monitoring and targeted interventions to address bacterial co-infections in COVID-19 patients. The diversity in resistance patterns, potential clonal spread, and robust biofilm-forming abilities among A. baumannii isolates underscore the importance of addressing this issue to better manage and treat critically ill COVID-19 patients.

Emergence of blaOXA-181-bearing tigecycline-resistant Klebsiella aerogenes in China.

We report the isolation of a blaOXA-181-positive, tigecycline-resistant Klebsiella aerogenes strain KA04 from a Chinese inpatient's fecal sample. Species identification was performed using MALDI-TOF MS. The antibiotic susceptibilities were assessed via the broth microdilution method. To elucidate the transmission and genetic structure of the blaOXA-181 gene, conjugation assays and whole-genome sequencing (WGS) were performed. KA04 displayed resistance to carbapenems, quinolones, piperacillin/tazobactam and tigecycline. Through WGS and conjugation experiments, it was possible to confirm blaOXA-181 and qnrS1 genes causing antibiotic resistance were located on a 51-kb IncX3 type mobile plasmid, blaOXA-181 gene could be successfully transferred into E. coli EC600 at a conjugation frequency of 1.1 × 10- 4. tet(A) gene was located on both the chromosome and non-transmissible IncFIB(K) plasmid. This is a tigecycline-resistant K. aerogenes harboring blaOXA-181 isolate from human fecal sample, highlighting a significant public health concern. Further comprehensive surveillance is needed.

Coexistence of seven different carbapenemase producers in a single hospital admission screening confirmed by whole-genome sequencing

ObjectiveTo molecularly characterize several extensively drug-resistant isolates from a single hospital admission screening of a war-injured patient from Ukraine. MethodsAdmission screening included swabs from skin, wounds, catheters, nasopharyngeum and rectum. Bacterial identification, antimicrobial susceptibility testing and rapid multiplex PCR assays targeting resistance genes were performed during routine diagnostics. Isolates positive by PCR had their genomes sequenced using short- and long read-platforms (MiSeq and MinION) to confirm species, identify resistance genes and plasmids and investigate clonality with core-genome MLST. ResultsSeven Gram-negative pathogens (Acinetobacter baumannii (n = 2; ST78, ST2), Klebsiella pneumoniae (n = 2; ST395), Pseudomonas aeruginosa (n = 1; ST1047), Escherichia coli (n = 1; ST46), Enterobacter cloacae complex (n = 1; ST231)) were molecularly confirmed non-identical. Antimicrobial susceptibility testing showed resistance to carbapenems (7/7 isolates) and last-resort treatment options such as ceftazidime-avibactam (6/7 isolates) and cefiderocol (4/7 isolates). All isolates were colistin susceptible. Sequencing identified the E. cloacae complex as Enterobacter hormaechei subsp. xiangfangensis. Six acquired carbapenemase genes (blaIMP-1, blaNDM-1, blaOXA-48, blaNDM-5, blaOXA-23 and blaOXA-72) were detected. Both A. baumannii isolates differed in sequence type, carbapenemases and cefiderocol susceptibility. Both K. pneumoniae isolates shared sequence type and some resistance genes on an IncR plasmid but were different in core-genome MLST and carbapenemases (OXA-48 or NDM-1). One vancomycin-resistant Enterococcus faecium was also detected (VanA). ConclusionsWar-injured patients from Ukraine may carry different clones of multidrug-resistant pathogens with limited treatment options and diverse resistance genes at risk for dissemination. Infection control measures should include early molecular characterization of isolates for detection of routes of transmission.

Insertion Sequences within Oxacillinases Genes as Molecular Determinants of Acinetobacter baumannii Resistance to Carbapenems-A Pilot Study.

Carbapenem-resistant Acinetobacter baumannii is one of the major problems among hospitalized patients. The presence of multiple virulence factors results in bacteria persistence in the hospital environment. It facilitates bacterial transmission between patients, causing various types of infections, mostly ventilator-associated pneumonia and wound and bloodstream infections. A. baumannii has a variable number of resistance mechanisms, but the most commonly produced are carbapenem-hydrolyzing class D β-lactamases (CHDLs). In our study, the presence of blaOXA-23, blaOXA-40 and blaOXA-51 genes was investigated among 88 clinical isolates of A. baumannii, including 53 (60.2%) strains resistant to both carbapenems (meropenem and imipenem) and 35 (39.8%) strains susceptible to at least meropenem. Among these bacteria, all the isolates carried the blaOXA-51 gene. The blaOXA-23 and blaOXA-40 genes were detected in two (5.7%) and three (8.6%) strains, respectively. Among the OXA-23 carbapenemase-producing A. baumannii strains (n = 55), insertion sequences (ISAba1) were detected upstream of the blaOXA-23 gene in fifty-two (94.5%) carbapenem-resistant and two (3.6%) meropenem-susceptible isolates. A. baumannii clinical strains from Poland have a similar antimicrobial resistance profile as those worldwide, with the presence of ISAba1 among blaOXA-23-positive isolates also being quite common. Carbapenem resistance among A. baumannii strains is associated with the presence of CHDLs, especially when insertion sequences are present.

The context of blaOXA-23 gene in Iraqi carbapenem-resistant Acinetobacter baumannii isolates belonging to global clone 1 and global clone 2.

Of the genes conferring resistance to carbapenems in Acinetobacter baumannii, the blaOXA-23 gene is the most widely found across the world. The gene carrying blaOXA-23 transposons in A. baumannii isolates of global clones GC1 and GC2 is found worldwide. Here, we examined whether transposons play a role in the dissemination of the blaOXA-23 in globally distributed clones, GC1 and GC2 A. baumannii isolates from Iraq. The 119 non-repetitive A. baumannii isolates including 94 recovered from clinical specimens and 25 isolates from hospital environment between September 2021 and April 2022 from different medical centers located at various regions in Baghdad, Iraq. The global clones (GC) and the genes encoding carbapenem resistance, including blaOXA-23, blaOXA-24, and blaOXA-58 were identified using multiplex PCR assays. Antibiotic susceptibility testing was performed by the Kirby-Bauer disk diffusion susceptibility method. The transposons carrying blaOXA-23 were examined using PCR mapping. In cases when carbapenem susceptible A. baumannii isolates were found, they were subjected to E test, full length sequencing of blaOXA-Ab (blaOXA-51-like) and Institut Pasteur multi-locus sequence typing scheme. All but two isolates (92 clinical and 25 environmental) were identified carbapenem-resistant A. baumannii (CRAB). Of 117 CRAB isolates, 20 belong to GC1, 19 contained blaOXA-23; of them, 17 isolates harbored the blaOXA-23 located on Tn2006. Among the 46 CRAB belonging to GC2, 39 contained blaOXA-23; of them, 34 carried the blaOXA-23 located on Tn2006. The remaining GC1 and GC2 isolates, one GC1 as well as one GC2 isolate, were susceptible to imipenem, doripenem, and meropenem and considered carbapenem-susceptible A. baumannii (CSAB). Full-length sequencing of the blaOXA-Ab and MLST for the two CSAB isolates belonging to GC1 and GC2 confirmed that the GC1 isolate belongs to ST 623 and contained an allele that encodes an blaOXA-69 variant of the blaOXA-Ab while the GC2 belong to ST2 and carried an blaOXA-66 variant. This study provides evidence for the dissemination of blaOXA-23 on the Tn2006 in CRAB isolates in Baghdad, Iraq. It appears that this transposon is widespread in GC1 and 2 isolates as in the other parts of the world. Interestingly, one GC1 and one GC2 isolate from Iraq were found to be susceptible to carbapenem while the isolates belonging to GC1 and GC2 have so far rarely been found to be susceptible to carbapenem globally.

Characteristics of Oral Acinetobacter spp. and Evolution of Plasmid-Mediated Carbapenem Resistance in Bacteremia Patients with Hematological Malignancies.

Patients with hematological malignancies are more susceptible to infections, leading to a poor prognosis. Acinetobacter colonization is a risk factor for secondary bacteremia. Antibiotic susceptibility phenotypes and genomic characteristics of 48 oral Acinetobacter spp. and one bloodstream Acinetobacter baumannii from patients with hematological malignancies were analyzed by antimicrobial susceptibility tests and whole-genome sequencing. We conducted comparative genomic analysis of oral and blood isolates from the same patient. A. baumannii was the most common (72.92%, 35/48) Acinetobacter species in oral Acinetobacter spp. isolates. Seventeen different A. baumannii sequence types were identified using the Pasteur MLST scheme; however, the dominant global clones GC1 and GC2 were not present. Among the isolates, 46 (95.8%) were carbapenem-susceptible Acinetobacter spp. One patient treated with meropenem for 15 days developed A. baumannii bacteremia 46 days after the isolation of oral A. baumannii AOR07. Oral and bloodstream isolates from the same patient were closely related to only four non-synonymous mutations on the chromosome. The bla OXA-58 gene was transferred between plasmids through XerCD-mediated recombination, leading to an elevated copy number, causing carbapenem resistance in bloodstream isolates. Oral Acinetobacter spp. may cause secondary bacteremia. The amplification and transfer of bla OXA-58 in the plasmids explained the increased carbapenem resistance in the bloodstream isolate.

Effect of X-ray radiation on Multi-drug Resistant (MDR) Enterobacteriaceae & P.aeruginosa isolated from burn unit patient. The phenotypic and molecular study, Biofilm formation

Background: Multi-drug-resistant (MDR) bacteria are a significant global health concern due to their elevated rates of morbidity and mortality in burn patients. In This study investigated the presence of multidrug-resistant pathogenic bacteria in individuals with burn injuries, the formation of biofilms, and the impact of X-ray radiation. Method: For this study Clinical swabs about120 burn patients were obtained between December 2023 and June 2024 from burn units at Ramadi and Falluja Teaching Hospitals. Both conventional and Vitek2(bioMérieux) methods were used to identify the bacterial isolates. The isolates were then divided into three multi-drug resistance groups. The Colorimetric method (MTP) detected biofilms. To detect blaOXA-23,blaOXA-48, Omp, and blaTEM resistance genes, multiplex PCR was used. This research used two lumbosacral spine X-ray levels. Two levels of radiation were used 40 (80KV) mAs and 51.2 (85KV). Result: Results of burn isolation revealed 30(27%) P.aeruginosa, 18(16%) k.pneumoniae, 7(6%) E.coli, 7(6%) P.mirabilis. Of the all isolates, 100% produced biofilm. The Multiplex-PCR analysis revealed that the blaTEM genes were the predominant ones, constituting 30% of the samples. Subsequently, blaOXA-23 constituted 24.5% of the cases, whereas Omp accounted for 22.7% and blaOXA-48 for 13.6%. The radiation impact of X-rays produced by two dosages, 40(80KV)mAs for 125msec and 51,2(85KV) mAs for 160msec, demonstrates that there is no effect or alteration in the resistance capacity of all the bacterial isolates tested. Conclusion: This study showed that burn unit isolates produce ESBLs, which is a major concern in the intensive care unit due to its high morbidity and potential mortality. These data match antibiotic phenotypic test results showing substantial cefepime resistance. All isolates forming biofilms, this may association with high pathogenicity. This demands quick intervention to manage nosocomial outbreaks. No X-ray effect was seen on susceptibility a burn unit bacterial isolate.

Molecular Characterization of Carbapenem and Colistin Resistance in Klebsiella pneumoniae Isolates Obtained from Clinical Samples at a University Hospital Center in Algeria.

The current study aimed to determine the molecular mechanisms of carbapenem and colistin resistance among the clinical isolates of Klebsiella pneumoniae from hospitalized patients admitted to a university hospital in Eastern Algeria. In total, 124 non-duplicate isolates of K. pneumoniae were collected from September 2018 to April 2019. Bacterial identification was performed using MALDI-TOF MS. The presence of extended spectrum β-lactamase (ESBL) genes, carbapenemase genes, chromosomal mutation and mcr genes in colistin-resistant K. pneumoniae were evaluated by PCR. ESBLs represented a rate of 49.1% and harbored blaCTX-M, blaTEM and blaSHV genes. Concerning carbapenems, 12 strains (9.6%) were resistant to ertapenem (MIC: 1-32 μg/mL), of which one strain (0.8%) was also resistant to imipenem (MIC: 32 μg/mL). Among these strains, nine (75%) harbored blaOXA-48 gene. Seven strains (5.6%) expressed resistance to colistin (MIC: 2-32 μg/mL), of which two harbored mcr-8 and mgrB genes simultaneously. The existence of a double resistance to colistin in the same strain is new in Algeria, and this could raise concerns about the increase in levels of resistance to this antibiotic (MIC: 32 μg/mL). The mgrB gene alone was observed in five isolates (71.4%), including two strains harboring blaOXA-48. This is the first report revealing the presence of K. pneumoniae strains carrying the blaOXA-48 gene as well as a mutation in the mgrB gene. Large-scale surveillance and effective infection control measures are also urgently needed to prevent the outbreak of various carbapenem- and colistin-resistant isolates.

Characterization of colistin-resistant carbapenemase producing Klebsiella pneumoniae in a river receiving wastewater treatment plant effluent.

Genes conferring antibiotic resistance phenotype, particularly to last resort antibiotics, pose a significant concern globally. Wastewater treatment plant (WWTP) effluent substantially contributes to antibiotic resistance in receiving rivers, threatening human health. Globally, colistin- and carbapenem-resistant Klebsiella pneumoniae infections cause high morbidity and mortality. We investigated colistin-resistant carbapenemase-producing K. pneumoniae (Co-CRKP) isolates in Kathajodi river receiving WWTP effluent, their resistance genes, and pathogenic potential. Four isolates (Co-CRKP-7, Co-CRKP-8, Co-CRKP-10, and Co-CRKP-15) exhibited extensively drug-resistant (XDR) phenotype, harbouring blaTEM-1, blaCTX-M-15, blaNDM-5, and blaOXA-48 genes. Colistin resistance was attributed to mutations in the pmrA and pmrB genes. Virulence genes (fimH, mrkD, entB, iucA, iutA, and irp1), capsular serotypes (K1, K2) and biofilm formation in the isolates explicated their pathogenicity. Furthermore, Inc plasmid replicons (Y, FrepB, P, K/B, L/M, N, FIA, A/C, and FIB) indicated the dissemination potential of the resistance genes in Co-CRKP isolates. The multi-locus sequence typing showed that Co-CRKP-7 and Co-CRKP-8 belonged to ST42, while Co-CRKP-10 and Co-CRKP-15 were ST16 and ST231, respectively. These high-risk clones carrying multidrug resistance and virulence genes, implicated in numerous outbreaks, have spread worldwide. Our findings emphasize the necessity for effective treatment of hospital wastes to restrict the spread of clinical isolates into aquatic environments.

The presence of genes encoding carbapenem-hydrolyzing oxacillinase and lack of carbapenem resistance in non-baumannii Acinetobacter misidentified as Acinetobacter baumannii causing bloodstream infections in a tertiary hospital over a 3-year period

ObjectiveThis study aims to analyze the genomic and clinical characteristics of Non-baumannii Acinetobacter strains misidentified as A. baumannii, causing bloodstream infections (BSIs) in our hospital. Materials and methodsWhole genome sequencing was performed and average nucleotide identity (ANI) was analyzed. Susceptibility testing was conducted using micro-broth methods. The distribution of antimicrobial resistance genes (ARGs) and mobile genetic elements (MGEs) was examined using online software tools. The prevalence of virulence factors (VFs) was investigated through nucleotide coding sequence comparisons. Genetic structures of blaOXA genes were analyzed by Gcluster software. Clinical information was collected from electronic medical records for patient characterization. ResultsANI analysis identified five strains as Acinetobacter pittii, with the remaining four identified as A. geminorum, A. nosocomialis, A. soli and A. bereziniae. The GC content of all isolates was less than 38.9 % except for A. soli 16,294. All Non-baumannii Acinetobacter strains were relatively susceptible to antibiotics, except for one A. pittii isolate. Nine blaOXA variants were identified in seven isolates, with two isolates co-carrying 2 different types of blaOXA. Twenty-four insertion sequences (ISs) were identified, with ISAba and IS17 being the primary ISs. Five A. pittii isolates shared the same genetic structures around blaOXA. Genes related to adherence, immune modulation, and nutritional/metabolic factors were the most frequent. Few VFs were detected in A. soli 16,294 and A.bereziniae 14,325. ConclusionsThe presence of carbapenem hydrolyzing oxacillinase encoding genes did not confer carbapenem resistance, possibly due to the lack of ISs in the blaOXA flanking sequences. Different blaOXA variants within distinct strains shared the same genetic structures, suggesting potential for multidrug resistance development, which warrants our attention.

Detection of extended-spectrum β-lactamase producing Escherichia coli in table eggs from Istanbul.

ESBL-producing Escherichia coli strains threaten public health and obligate the use of last-resort antibiotics. This study identified 15 E. coli isolates through 16S rRNA and gyrB genes, specific to E. coli, in 120 egg samples (12.5%). Antibiotic resistance was detected according to the EUCAST and CLSI in E. coli isolates. 2 isolates were susceptible to all antibiotics, one isolate was resistant to one antibiotic, one isolate was resistant to 2 antibiotics, and 11 E. coli isolates (73.3%) had multidrug resistance. Most frequent antibiotic resistances were detected against ampicillin (80%), tetracycline (66.6%), and chloramphenicol (66.6%). A double-disc confirmation test was used to detect ESBL production, and blaTEM, blaSHV, blaCTX-M and blaOXA genes were searched by PCR. The blaTEM (100%) gene was found in all resistant E. coli isolates, and the blaCTX-M gene was detected in only 3 (20%) E. coli isolates. None of the E. coli isolates contained the genes responsible for carbapenem and colistin resistance. Our results show that multi-drug antibiotic resistance and the blaTEM gene are frequent in E. coli from table eggs in Istanbul. This is the first preliminary study on ESBL-producing E. coli isolates in table eggs in Türkiye.

Presence of extended-spectrum beta-lactamase-producing Escherichia coli and carbapenem resistance in ready-to-eat stuffed mussels in Istanbul

AbstractFoodborne pathogens' transmission is essential in the spread of antibiotic resistance, and extended-spectrum beta-lactamase-producing Escherichia coli especially threatens public health. E. coli plays an essential role in the resistance to commonly used beta-lactam group antibiotics. Ready-to-eat (RTE) stuffed mussels are among many restaurants and street vendors, presenting potential health risks of food hygiene origin. 200 RTE stuffed mussels were collected from the Asian and European sides of Istanbul and analysed for the presence of E. coli. As a result of PCR analysis, E. coli was detected in 7 (3.5%) samples. An antibiotic susceptibility test was performed using the disc diffusion method to determine ESBL and carbapenem resistance. All isolates were resistant to ampicillin. The double-disk synergy test was performed as an ESBL phenotypic confirmation test, and no phenotypically ESBL-producing E. coli were detected. The blaTEM gene was detected in one isolate (14.2%) by mPCR, but blaCTX-M, blaSHV, and blaOXA genes were not observed. Meropenem and imipenem were used with the disk diffusion method for carbapenem resistance study, and no resistant isolate was found. Carbapenem resistance genes were investigated by monoplex PCR, and blaNDM-1, blaOXA-48, blaVIM, and blaIMP resistance genes were not detected. This is the first report on ESBL-producing E. coli in RTE stuffed mussels in Türkiye, which draws attention to a public health risk.

Prevalence Of Some Pyogenic Organisms In Skin Wound Infections In Sheep And Goat

Background: Pyogenic bacterial infections are broadly found worldwide among sheep and goats and are adversely impacting the development of the small ruminants’ industry. The study was performed to identify and characterize most prevalent bacteria isolated from skin and wound infections of sheep and goat of various rearing condition in Egypt. Materials and Methods: One hundred and fifteen pus samples (sheep≈70) and (goat≈45) obtained from skin abscesses and pyogenic wounds during the study period 2022-2023. The samples were cultured onto suitable media, microscopically and biochemically tested. The obtained isolates were assessed for their antibiotic susceptibility and subjected to polymerase chain reaction to detect certain genes which responsible for the virulence and antibiotic resistance. Results: Bacterial isolates were recovered from 83 out of the 115 collected pus samples (72.17%) with pure isolation were obtained in 68 cultures. The bacterial isolation was achieved in 88.57% and 46.66% from sheep and goat respectively. Pseudomonas aeruginosa were recovered as 19.35% from sheep and 23.81% from goat while Staphylococcus aureus were isolated as 46.77% and 38.09% from sheep and goat respectively. Regarding Corynebacterium pseudotuberculosis was obtained from 37.09% of sheep and 9.52% of goat samples. P. aeruginosa isolates were highly sensitive to erythromycin, amikacin, ampicillin /sulbactam and cefoxitin and high resistance to amoxicillin /clavulanic acid, clindamycin, and quinolones with 58.82% MDR pattern. S. aureus isolates revealed the high sensetivity to amikacin, imipenem and clindamycin but high resistant to quinolones with 21.62% act as MDR. C. pseudotuberculosis isolates were sensitive to most of tested antibiotics except amoxicillin /clavulanic acid and clindamycin. PCR assays revealed that P. aeruginosa isolates carried toxA and blaOXA-1 genes by 35.29% and 64.70% respectively while S. aureus isolates was found to load eta gene by 13.51% and ermC gene 18.91% and in the same line ten C. pseudotuberculosis was found to harbor pld gene 40%. Conclusion: It was concluded that Pseudomonas aeruginosa, Staphylococcus aureus as well as Corynebacterium pseudotuberculosis were the most isolated bacterial species in skin infection among sheep and goat in Egypt. Majority of the isolates were MDR and highly resistant to β lactams and quinolones but sensitive to amikacin and imipenem. PCR assays revealed that the isolates carried virulence and antibiotic resistance genes in significant incidence.

Prevalence and Molecular Characterization of Carbapenem and Colistin-Resistance Genes in Clinical Strains of Pseudomonas aeruginosa Isolated from Diabetic Patients

Abstract Introduction Pseudomonas aeruginosa is one of the important opportunistic nosocomial pathogens that are increasingly becoming resistant to many drugs including the drugs of last resort, carbapenems, and colistin. Methods The study involved the examination of clinical isolates of P. aeruginosa recovered from diabetic patients for the presence of acquired genes implied in carbapenem and colistin resistance. Results A total of 100 clinical isolates from diabetic patients' wound and sputum were investigated for their susceptibility to imipenem and colistin followed by phenotypic assay and resistance gene screening. The study revealed 27 sputum isolates being resistant to imipenem further confirmed by a modified Hodge test and 28 wound isolates were resistant to colistin. The resistant isolates of wound and sputum were found to possess blaOXA-48 , blaVIM , mcr-1, and mcr-5 genes. The strains had a coexistence of carbapenem- and colistin-resistant genes. Conclusion Considering the fact that infection by such resistant isolates in diabetics could be frightening, clinical laboratories must employ rapid diagnostic methods to detect resistance which can aid in the treatment decision-making.

Carbapenems and colistin resistance genes isolated in Musca domestica from a garbage dump near a hospital in Lima.

Motivation for the study. The presence of antibiotic resistance genes in bacteria isolated from common flies is a potential public health hazard because it facilitates the presence and spread of antibiotic resistance genes in the environment. Main findings. Thirty-eight bacterial strains identified in 14 species were isolated from within the fly bodies, of which 31 strains showed resistance to carbapenems and 26 strains showed resistance to colistin. Seven bacterial strains showed carbapenem resistance genes and one Escherichia coli strain had resistance to KPC, OXA-48 and mcr-1. Implications. This is the first report of antibiotic resistance genes in bacteria carried by common flies in Peru. The objective was to determine the presence of carbapenem resistance genes and plasmid resistance to colistin (mcr-1) in bacteria isolated from Musca domestica in a garbage dump near a hospital in Lima, Peru. Bacteria with phenotypic resistance to carbapenemics were isolated on CHROMagar mSuperCARBATM medium and colistin resistance profiling was performed using the colistin disk elution method. Detection of blaKPC, blaNDM, blaIMP, blaOXA-48, blaVIM and mcr-1 genes was performed by conventional PCR. The antimicrobial susceptibility profile was determined using the automated MicroScan system. We found that 31/38 strains had phenotypic resistance to carbapenemics and 26/38 strains had phenotypic resistance to colistin with a minimum inhibitory concentration ≥ 4 µg/ml. Finally, we identified seven bacterial strains with carbapenem resistance genes (OXA-48 and KPC) and one bacterial strain with plasmid resistance to colistin (mcr-1). One Escherichia coli strain had three resistance genes: KPC, OXA-48 and mcr-1.

Tracing Acinetobacter baumannii's Journey from Hospitals to Aquatic Ecosystems.

This study provides a comprehensive analysis of Acinetobacter baumannii in aquatic environments and fish microbiota by integrating culture-dependent methods, 16S metagenomics, and antibiotic resistance profiling. A total of 83 A. baumannii isolates were recovered using culture-dependent methods from intra-hospital infections (IHI) and wastewater (WW) and surface water (SW) samples from two southern Romanian cities in August 2022. The antibiotic susceptibility was screened using disc diffusion, microdilution, PCR, and Whole Genome Sequencing assays. The highest microbial load in the analyzed samples was found in Glina, Bucharest, for both WW and SW samples across all investigated phenotypes. For Bucharest isolates, the resistance levels corresponded to fluoroquinolones > aminoglycosides > β-lactam antibiotics. In contrast, A. baumannii from upstream SW samples in Târgoviște showed the highest resistance to aminoglycosides. The blaOXA-23 gene was frequently detected in IHI, WW, and SW isolates in Bucharest, but was absent in Târgoviște. Molecular phylogeny revealed the presence of ST10 in Târgoviște isolates and ST2 in Bucharest isolates, while other minor STs were not specifically correlated with a sampling point. Using 16S rRNA sequencing, significant differences in microbial populations between the two locations was identified. The low abundance of Alphaproteobacteria and Actinobacteria in both locations suggests environmental pressures or contamination events. These findings indicate significant fecal contamination and potential public health risks, emphasizing the need for improved water quality monitoring and management.

Whole genome sequencing insight into carbapenem-resistant and multidrug-resistant Acinetobacter baumannii harboring chromosome-borne blaOXA-23.

Carbapenem-resistant Acinetobacter baumannii (CRAB) poses a significant threat to hospitalized patients as effective therapeutic options are scarce. Based on the genomic characteristics of the CRAB strain AB2877 harboring chromosome-borne blaOXA-23, which was isolated from the bronchoalveolar lavage fluid (BALF) of a patient in a respiratory intensive care unit (RICU), we systematically analyzed antibiotic resistance genes (ARGs) and the genetic context associated with ARGs carried by CRAB strains harboring chromosome-borne blaOXA-23 worldwide. Besides blaOXA-23, other ARGs were detected on the chromosome of the CRAB strain AB2877 belonging to ST208/1806 (Oxford MLST scheme). Several key genetic contexts associated with the ARGs were identified on the chromosome of the CRAB strain AB2877, including (1) the MDR region associated with blaOXA-23, tet(B)-tetR(B), aph(3'')-Ib, and aph(6)-Id (2); the resistance island AbGRI3 harboring armA and mph(E)-msr(E) (3); the Tn3-like composite transposon containing blaTEM-1D and aph(3')-Ia; and (4) the structure "ISAba1-blaADC-25." The first two genetic contexts were most common in ST195/1816, followed by ST208/1806. The last two genetic contexts were found most frequently in ST208/1806, followed by ST195/1816.IMPORTANCEThe blaOXA-23 gene can be carried by plasmid or chromosome, facilitating horizontal genetic transfer and increasing carbapenem resistance in healthcare settings. In this study, we focused on the genomic characteristics of CRAB strains harboring the chromosome-borne blaOXA-23 gene, and the important genetic contexts associated with blaOXA-23 and other ARGs were identified, and their prevalent clones worldwide were determined. Notably, although the predominant clonal CRAB lineages worldwide containing the MDR region associated with blaOXA-23, tet(B)-tetR(B), aph(3'')-Ib, and aph (6)-Id was ST195/1816, followed by ST208/1806, the CRAB strain AB2877 in our study belonged to ST208/1806. Our findings contribute to the knowledge regarding the dissemination of CRAB strains and the control of nosocomial infection.