ompA Gene Research Articles

The predominance of virulence genes associated with multidrug-resistant Serratia marcescens isolated from urinary tract infections

Purpose: Serratia marcescens owns different virulence factors that contribute to their pathogenesis and result in bacterial invasion and resistance. Moreover, patients who suffer from urinary tract infections (UTIs) are at an increased risk of contracting different bacterial infections. This study aimed to detect and verify the occurrence of virulence genes in S. marcescens isolated from patients with UTIs in some hospitals in Iraq. Methodology: After bacterial collection, the identification was achieved by busing phenotypic and genotypic methods. The antibiotic susceptibility patterns were done by using the VITEK2 compact system AST 69 and minimum inhibitory concentration for the colistin antibiotic was detected by the broth micro-dilution assay. The PCR was employed for the detection of virulence genes including papC, fimH, ompA, and entB genes. Results: S. marcescens had a high level of resistance to antibiotics. The prevalence rate of virulence genes in S. marcescens was: papC (100%), fimH (47.3%), ompA (32.8%), and entB (30.2%). We found that the number papC was the most predominant gene in the clinical S. marcescens. RT-qPCR showed over expression of papC as compared to the 16rRNA gene, may explains the predominant. Conclusions: This study shows that there is a high prevalence of virulence genes in S. marcescens isolated from UTI with high antibiotic resistance capacity. Moreover, necessitates for further studies on virulence factors using modern molecular techniques are recommended to straighten the drug-resistant profiles of bacterial isolates to develop novel antimicrobials utilizing strategies which target pathogenic bacteria's virulence genes in order to provide efficient clinical treatment.

Diversity and Phylogeny of Cattle Ixodid Ticks and Associated Spotted Fever Group Rickettsia spp. in Tunisia.

Tick-borne rickettsioses are mainly caused by obligate intracellular bacteria belonging to the spotted fever group (SFG) of the Rickettsia genus. So far, the causative agents of SFG rickettsioses have not been detected in cattle ticks from Tunisia. Therefore, the aim of this study was to investigate the diversity and phylogeny of ticks associated with cattle from northern Tunisia and their associated Rickettsia species. Adult ticks (n = 338) were collected from cattle in northern Tunisia. The obtained ticks were identified as Hyalomma excavatum (n = 129), Rhipicephalus sanguineus sensu lato (n = 111), Hyalomma marginatum (n = 84), Hyalomma scupense (n = 12) and Hyalomma rufipes (n = 2). After DNA extraction from the ticks, 83 PCR products based on the mitochondrial 16S rRNA gene were sequenced and a total of four genotypes for Rh. sanguineus s.l., two for Hy. marginatum and Hy. excavatum and only one for Hy. scupense and Hy. rufipes were recorded, with the occurrence of one, two and three novel genotypes, respectively, for Hy. marginatum, Hy. excavatum and Rh. sanguineus s.l. mitochondrial 16S rRNA partial sequences. The tick DNA was tested for the presence of Rickettsia spp. by using PCR measurements and sequencing targeting three different genes (ompB, ompA and gltA). Of the 338 analyzed ticks, 90 (26.6%), including 38 (34.2%) Rh. sanguineus s.l., 26 (20.1%) Hy. excavatum, 25 (29.8%) Hy. marginatum and one (50%) Hy. rufipes tick, were positive for Rickettsia spp. Based on 104 partial sequences of the three analyzed genes, the BLAST analysis and phylogenetic study showed the infection of Hy. excavatum, Hy. marginatum and Rh. sanguineus s.l. tick specimens with R. massiliae, R. aeschlimannii and R. sibirica subsp. mongolitimonae and one Hy. rufipes tick specimen with R. aeschlimannii. In addition, coinfection with R. massiliae and R. aeschlimannii was reported in one Hy. marginatum and one Rh. sanguineus s.l. tick specimen, while a coinfection with R. massiliae and R. sibirica subsp. mongolitimonae was recorded in one Rh. sanguineus s.l. tick specimen. In conclusion, our study reports, for the first time in Tunisia, the infection of cattle ticks belonging to Hyalomma and Rhipicephalus genera with zoonotic Rickettsia species belonging to the SFG group.

Detection of biofilm-related genes and antibiotic resistance in Acinetobacter baumannii isolated from clinical specimens

Abstract. Saadulla SOK, Muhammed SM. 2023. Detection of biofilm-related genes and antibiotic resistance in Acinetobacter baumannii isolated from clinical specimens. Biodiversitas 24: 1809-1816. A total of 53 Acinetobacter baumannii clinical isolates were collected from patients treated at Shar Hospital in Sulaimani city to determine antibiotic susceptibility patterns and their association between biofilm formation and the distribution of biofilm-related genes. Identification of suspected A. baumannii was carried out by conventional and molecular approaches, including 16S rRNA and blaoxa-51 gene amplification. In addition, disk diffusion and microtiter plate methods determined antibiotic susceptibility and biofilm-forming capability, respectively. Out of 53 A. baumannii clinical isolates 42 (79.24%), were Multidrug-Resistant (MDR), of which 3 (5.66%) were resistant to colistin. Overall, 33 (62.26%) of the clinical isolates were strong biofilm producers, 6 (11.32%) were moderate or weak biofilm producers, and 8 (15.09%) were non-biofilm-forming isolates. The frequency of biofilm-related genes ompA, bap, csuE, blaPER-1, and cpaA among A. baumannii strains was 92.45%, 79.24%, 73.58%, 9.43%, and 7.54%, respectively. The high frequency of multi-drug resistant strains, and their ability to form biofilms, is a potential threat to effective therapy and may increase morbidity and mortality in infected patients. Colistin appeared to be the most effective antibiotic for treating MDR A. baumannii infections.

Genotyping of rickettsias circulating in the territories of the Altai Republic and Khabarovsk krai

The aim of the study was to verificate of the causative agent of Siberian tick-borne typhus (STT) upon ixodic tick mixed infection on the territory of the Altai Republic and Khabarovsk Krai using an integrated molecular biological approach. Materials and methods. The material for the study was presented as 304 imago of ixodic mites of six species. The ticks were collected on the territory of the Altai Republic and the Khabarovsk Krai in the years 20142022. Rickettsia DNA was identified by two-round PCR using genus- and species-specific primers for gltA and ompA genes, followed by sequencing and using PCR reagent kits RealBest DNA R. sibirica/R. heilongjiangensis (Vector-Best, Novosibirsk). Results. The detection of rickettsia in ticks in the Altai Republic was 82.6% (CI: 69.196.1), in the Khabarovsk Krai 53.1% (CI: 44.961.3). The species composition of rickettsias in various species of ixodic mites in these territories, endemic to Siberian tick typhus, is characterized by the presence of mixed forms. Rickettsia sibirica and R. raoultii were found in ticks Dermacentor nuttalli, Haemaphysalis concinna, D. silvarum. Only Candidatus R. tarasevichiae were detected in Ixodes persulcatus, I. pavlovsky mites and I. pavlovsky/persulcatus hybrids. The DNA of R. heilongjiangensis was found in H. mites. concinna in the Khabarovsk Krai. The DNA of Candidatus R. tarasevichiae is also present in the ticks of D. nuttalli and H. concinna from the Altai Republic. The DNA of the classic pathogenic species, R. sibirica, was detected in ticks D. nuttalli and H. concinna in the Altai Republic, ticks D. silvarum, H. concinna and H. japonica douglasi in the Khabarovsk Krai. In addition, in the Khabarovsk Krai, the DNA of R. heilongjiangensis was detected in H. concinna ticks, and a DNA fragment common to R. sibirica subsp. mongolitimonae and R. conorii was detected in H. japonica douglasi ticks, which requires further study. Candidatus R. tarasevichiae is common in Ixodes mites (I. persulcatus, I. pavlovsky and their hybrids), in the Altai Republic in D. nuttalli and H. concinna. R mites. raoultii was detected in ticks of the genus Dermacentor D. nuttalli in the Altai Republic and D. silvarum in the Khabarovsk Krai. Conclusions. During molecular biological monitoring of rickettsias in endemic territories, the detection of R. raoultii masks the presence of the etiological agent of STT R. sibirica. This phenomenon makes it possible to explain the high incidence of STT in the studied territories, with the rare detectability of R. sibirica DNA during molecular biological screening in ixodic mites.

Characteristics of rectal chlamydia among men who have sex with men in southern Taiwan, 2020-2022: An emerging threat of rectal lymphogranuloma venereum L2b.

The prevalence of rectal chlamydia among men who have sex with men (MSM) without human deficiency virus infection (non-HIV) remains uncertain in Taiwan, and rectal lymphogranuloma venereum (LGV) among MSM has never been reported in the Far East. From January 2020 to April 2022, MSM coming for anonymous voluntary counseling and testing, for pre-exposure prophylaxis, and for antiretroviral therapy were enrolled. All participants submitted his fecal samples and completed a QR-code questionnaire. Medical records of those who took regular medical visits for HIV were recorded. Multiplex polymerase chain reaction (PCR) was performed for all fecal samples, and ompA gene sequencing was therefore performed for each Chlamydia-positive fecal sample. Among 341 MSM during 2020-2022 in southern Taiwan, 21 (6.2%) had rectal chlamydia infection. Risk factors of rectal chlamydia included co-infection with rectal gonorrhea (adjusted odds ratio [AOR] 6.78, 95% confidence interval [CI] 1.44-31.91, P=0.015) and multiple sexual partners (AOR 1.373, 95% CI 1.002-1.882, P=0.048). Further ompA gene sequencing from 19 Chlamydia-positive fecal samples revealed that the prevalent genotypes or genovariants were Da (26.3%) and L2b (26.3%), followed by B (21.1%), J (14.3%), and G (9.5%). All cases of rectal LGV genovariant L2b presented as acute proctitis with diarrhea, anal pain, or discharge and were treated successfully with prolonged treatment of doxycycline. Rectal gonorrhea and multiplex sexual partners are risk factors for rectal chlamydia. Clinicians in Taiwan should be aware of the emerging threat of rectal LGV among MSM with acute proctitis.

In silico and in vitro studies of GENT-EDTA encapsulated niosomes: A novel approach to enhance the antibacterial activity and biofilm inhibition in drug-resistant Klebsiella pneumoniae

Klebsiella pneumoniae (Kp) is a common pathogen inducing catheter-related biofilm infections. Developing effective therapy to overcome antimicrobial resistance (AMR) in Kp is a severe therapeutic challenge that must be solved. This study aimed to prepare niosome-encapsulated GENT (Gentamicin) and EDTA (Ethylenediaminetetraacetic acid) (GENT-EDTA/Nio) to evaluate its efficacy toward Kp strains. The thin-film hydration method was used to prepare various formulations of GENT-EDTA/Nio. Formulations were characterized for their physicochemical characteristics. GENT-EDTA/Nio properties were used for optimization with Design-Expert Software. Molecular docking was utilized to determine the antibacterial activity of GENT. The niosomes displayed a controlled drug release and storage stability of at least 60 days at 4 and 25 °C. GENT-EDTA/Nio performance as antimicrobial agents has been evaluated by employing agar well diffusion method, minimum bactericidal concentration (MBC), and minimum inhibitory concentration (MIC) against the Kp bacteria strains. Biofilm formation was investigated after GENT-EDTA/Nio administration through different detection methods, which showed that this formulation reduces biofilm formation. The effect of GENT-EDTA/Nio on the expression of biofilm-related genes (mrkA, ompA, and vzm) was estimated using QRT-PCR. MTT assay was used to evaluate the toxicity effect of niosomal formulations on HFF cells. The present study results indicate that GENT-EDTA/Nio decreases Kp's resistance to antibiotics and increases its antibiotic and anti-biofilm activity and could be helpful as a new approach for drug delivery.

Prevalence and Risk Factors of Avian Chlamydiosis Detected by Polymerase Chain Reaction in Psittacine Birds in Thailand.

This study surveyed avian chlamydiosis, with the aim to estimate the prevalence and potential risk factors associated with Chlamydia psittaci infection in psittacine birds kept as domestic pets in Thailand. Oropharyngeal swabs were collected from 120 psittacine birds that were randomly selected from hospitals in the central (Bangkok) and northeastern regions (Khon Kaen) of Thailand between 2019 and 2021. The oropharyngeal swabs were subject to polymerase chain reaction testing to detect the C psittaci ompA gene. The prevalence of C psittaci was 2.5% (3/ 120, 95% confidence interval = 0.3-5.3). Of the 3 positive birds, 1 was a Forpus parrot (Forpus species)(CP43TH) and 1 was an African grey parrot (Psittacus erithacus)(CP49TH) from Bangkok; both were juvenile birds with clinical signs of disease. The third positive bird (CP12TH) was a subclinical adult sun conure (Aratinga solstitialis) from Khon Kaen. Two sequences of samples that were previously identified in human psittacosis cases (accession numbers MK032053.1 and HM450409.1) were also examined. Since there was a low number of infected birds, potential associations between C psittaci infection and various environmental variables (eg, cage cleaning, synanthropic birds, quarantine of new birds, and overcrowding) were assessed by Fisher exact tests. This study provides estimates of the prevalence and potential risk factors associated with C psittaci infection in psittacine birds from central (Bangkok) and the northeastern regions (Khon Kaen) of Thailand. The detection of C psittaci in captive psittacine birds demonstrates that there is a possibility for bird-to-bird transmission as well as some zoonotic potential for the human caretakers of these birds. Furthermore, larger-scale studies should be conducted to confirm these findings.

Visual and rapid identification of Chlamydia trachomatis and Neisseria gonorrhoeae using multiplex loop-mediated isothermal amplification and a gold nanoparticle-based lateral flow biosensor.

Sexually transmitted chlamydia and gonorrhea infections caused by the bacteria Chlamydia trachomatis and Neisseria gonorrhoeae remain a major public health concern worldwide, particularly in less developed nations. It is crucial to use a point of care (POC) diagnostic method that is quick, specific, sensitive, and user-friendly to treat and control these infections effectively. Here, a novel molecular diagnostic assay, combining multiplex loop-mediated isothermal amplification (mLAMP) with a visual gold nanoparticles-based lateral flow biosensor (AuNPs-LFB) was devised and used for highly specific, sensitive, rapid, visual, and easy identification of C. trachomatis and N. gonorrhoeae. Two unique independent primer pairs were successful designed against the ompA and orf1 genes of C. trachomatis and N. gonorrhoeae, respectively. The optimal mLAMP-AuNPs-LFB reaction conditions were determined to be 67°C for 35min. The detection procedure, involving crude genomic DNA extraction (~5 min), LAMP amplification (35min), and visual results interpretation (<2min), can be completed within 45min. Our assay has a detection limit of 50 copies per test, and we did not observe any cross-reactivity with any other bacteria in our testing. Hence, our mLAMP-AuNPs-LFB assay can potentially be used for POC testing to detect C. trachomatis and N. gonorrhoeae in clinical settings, particularly in underdeveloped regions.

The life cycle of Dermacentor nuttalli from the Qinghai-Tibetan Plateau under laboratory conditions and detection of spotted fever group Rickettsia spp.

Dermacentor nuttalli has been a focus of study because tick-borne pathogens have been widely identified in this tick from northern and southwestern China. The aim of this study was to characterize the life cycle of D. nuttalli under laboratory conditions and to detect spotted fever group (SFG) Rickettsia in the midgut and salivary glands of both field-collected and first laboratory generation adults. D. nuttalli ticks were collected in the field on the Qinghai-Tibetan Plateau from March to April 2021 and their life cycle was studied under laboratory conditions. Tick identify was molecularly confirmed, and SFG Rickettsia were detected in the midgut and salivary glands of males and females by PCR targeting different rickettsial genes. The results showed that the life cycle of D. nuttalli under laboratory conditions was completed in an average of 86.1 days. High positivity of Rickettsia spp. was detected in the midgut and salivary glands of both males (92.0%) and females (93.0%) of field-collected D. nuttalli ticks. However, a relatively lower positivity (4.0-6.0%) was detected in first laboratory generation adults. Furthermore, sequencing analysis showed that the Rickettsia sequences obtained in this study shared 98.6 to 100% nucleotide identity with Rickettsia slovaca and Rickettsia raoultii isolated from Dermacentor spp. in China. Phylogenetic analysis of Rickettsia spp. based on the gltA, ompA, ompB and sca4 genes revealed that the Rickettsia sequences obtained could be classified as belonging to R. slovaca and R. raoultii clades. This study described for the first time the life cycle of D. nuttalli from the Qinghai-Tibetan Plateau under laboratory conditions. Two species of SFG Rickettsia were detected in the midgut and salivary glands of males and females in both field-collected and first laboratory-generation adults of D. nuttalli. Our study provides new insights into pathogen detection in ticks in the Qinghai-Tibet Plateau, and the relationships among hosts, ticks, and pathogens.

OmpA is involved in the invasion of duck brain microvascular endothelial cells by Riemerella anatipestifer

Bacterial meningitis is a major cause of morbidity and mortality. Despite advances in antimicrobial chemotherapy, the disease remains detrimental to humans, livestock, and poultry. Riemerella anatipestifer is a gram-negative bacterium causing duckling serositis and meningitis. However, the virulence factors contributing to its binding and invasion of duck brain microvascular endothelial cells (DBMECs) and penetration of the blood-brain barrier (BBB) have never been reported. In this study, immortalized DBMECs were successfully generated and used as an in vitro-model of duck BBB. Furthermore, ompA gene deletion mutant of the pathogen and multiple complemented strains carrying the complete ompA gene and its truncated forms were constructed. Bacterial growth, invasion, and adhesion assays and animal experiments were performed. The results show that the OmpA protein of R. anatipestifer had no effect on bacterial growth and adhesion ability to DBMECs. The role of OmpA in the invasion of R. anatipestifer into DBMECs and duckling BBB was confirmed. The amino acids 230–242 of OmpA represents a key domain involved in R. anatipestifer invasion. In addition, another OmpA1164 protein constituted by the amino acids 102–488 within OmpA could function as a complete OmpA. The signal peptide sequence from amino acids 1–21 had no significant effect on OmpA functions. In conclusion, this study illustrated that OmpA is an important virulence factor mediating R. anatipestifer invasion of DBMECs and penetration of the duckling BBB.

First study on capsular serotypes and virulence factors of Pasteurella multocida isolates from Phan Rang sheep in Vietnam.

Pasteurella multocida is considered as a main factor mediating pneumonic pasteurellosis in ruminants, including sheep. It is also a current threat to Phan Rang sheep in Vietnam. This study aimed to characterize P. multocida isolated from Phan Rang sheep, their antibiotic resistance profile, and the prevalence of some virulence-associated genes of these strains. Bacteria were isolated on brain heart infusion, 10% sheep blood agar plates, and screened by biochemical tests. The polymerase chain reaction technique was used with specific primers to identify P. multocida, the presence of virulence-associated genes, and serotypes of isolates. Antimicrobial susceptibility and biofilm formation of isolates were examined using the disk diffusion method and crystal violet-based method, respectively. A total of 41 P. multocida strains were isolated from 485 samples from clinically sick and healthy sheep. Of the isolates, 58.53% were serotype A, 9.75% were serotype B, and 31.71% were serotype D. Healthy animals were infected with serotype D only. All 15 virulence genes were identified in all strains isolated from clinically sick sheep, while strains isolated from healthy sheep carried 11/15 virulence genes tested. Among virulence-associated genes exbB, exbD, tonB, ompA, oma87, fimA, hgbA, and nanB were detected in over 90% of isolates, whereas hgbB, nanH, tbpA and pfhA were less frequent. Interestingly, pmHAS and tadD were highly prevalent in capsular type A strains, whereas the toxA gene was detected in capsular type D strains only. All of the isolated strains were fully susceptible to enrofloxacin, ciprofloxacin, neomycin, and ofloxacin. About 92.68% were susceptible to chloramphenicol and 90.24% to amikacin, but there was high resistance to erythromycin, tetracycline, and amoxicillin. Our results reveal that 53.65% of 41 isolates could produce biofilm, whereas 46.34% could not. Pasteurella multocida from Phan Rang sheep possess many virulence genes and resistance to several common antibiotics such as erythromycin, tetracycline, and amoxicillin. The results are an important warning regarding antibiotic resistance of P. multocida.

Molecular Characterization and Phylogenetic Analysis of Outer membrane protein P2 (OmpP2) of Glaesserella (Haemophilus) parasuis Isolates in Central State of Peninsular Malaysia

Glaesserella (Haemophilus) parasuis, the etiological agent of Glässer's disease, is an economically significant pathogen commonly associated with serofibrinous polyserositis, arthritis, fibrinous bronchopneumonia and/or meningitis. This study is the first attempt to molecularly characterize and provide a detailed overview of the genetic variants of G. parasuis present in Malaysia, in reference to its serotype, virulence-associated trimeric autotransporters (vtaA) gene and outer membrane protein P2 (OmpP2) gene. The G. parasuis isolates (n = 11) from clinically sick field samples collected from two major pig producing states (Selangor and Perak) were selected for analysis. Upon multiplex PCR, the majority of the isolates (eight out of 11) were identified to be serotype 5 or 12, and interestingly, serotypes 3, 8 and 15 were also detected, which had never been reported in Malaysia prior to this. Generally, virulent vtaA was detected for all isolates, except for one, which displayed a nonvirulent vtaA. A phylogenetic analysis of the OmpP2 gene revealed that the majority of Malaysian isolates were clustered into genotype 1, which could be further divided into Ia and Ib, while only one isolate was clustered into genotype 2.

Molecular detection of Rickettsia, Anaplasma, and Bartonella in ticks from free-ranging sheep in Gansu Province, China

Ticks pose a serious threat to public health as carriers and often vectors of zoonotic pathogens. There are few systematic studies on the prevalence and genetic diversity of tick-borne bacterial pathogens in Western China. In this study, 465 ticks were collected from free-ranging sheep in Gansu Province in China. Ticks were divided into 113 pools and tick DNA was extracted from these ticks. PCR assays were performed using specific primers to screen for tick-borne pathogens as well as sequence analysis based on the 16S rRNA (rrs), ompB, gltA, ompA genes for Rickettsia, rrs, groEL genes for Anaplasma, and ssrA and rpoB genes for Bartonella. The PCR results showed that the minimum infection rates with Rickettsia, Anaplasma, and Bartonella were 16.8% (78/465), 18.9% (88/465), and 0.9% (4/465), respectively. Sequence analysis based on the concatenated sequences of rrs-ompB-gltA-ompA indicated that the Rickettsia species identified in the ticks belonged to Rickettsia raoultii, Rickettsia slovaca, and Rickettsia sibirica, respectively; phylogenetic analysis based on the groEL gene showed that all Anaplasma strains identified were Anaplasma ovis; and phylogenetic analysis based on the ssrA and rpoB genes indicated that all Bartonella strains in the ticks belonged to Bartonella melophagi. The results of this study showed that ticks in Gansu Province harbored multiple pathogens that may cause rickettsial diseases and bartonellosis. These diseases were neglected in the area and physicians and public health workers need to pay attention to their diagnoses to prevent human infection.

Epidemiological Features and Impact of High Glucose Level on Virulence Gene Expression and Serum Resistance of Klebsiella pneumoniae Causing Liver Abscess in Diabetic Patients.

Klebsiella pneumoniae (K. pneumoniae) is a Gram-negative bacterium that is predominantly associated with liver abscesses in global diabetic patients. High levels of glucose in the surrounding of K. pneumonia increase its pathogenicity including capsular polysaccharide (CPS) and fimbriae. Other important virulent factors include outer membrane protein A (ompA) and regulator mucoid phenotype A (rmpA). The objective of this investigation was to elucidate the effects of high glucose on rmpA and ompA gene expression and serum resistance of K. pneumoniae causing liver abscess. The clinical history of 57 patients suffering from K. pneumoniae-causedliver abscesses (KLA) was acquired and their clinical and laboratory manifestations in the presence or absence of diabetes were analyzed. The antimicrobial susceptibility, serotypes, and virulence genes were tested. Clinical isolates of 3 serotype-K1 hypervirulent K. pneumoniae (hvKP) were used to detect the effect of exogenous high glucose on rmpA, ompA, and clbB genes expression, and bacterial serum resistance. KLA patients with diabetes showed higher C-reactive protein (CRP) compared to non-diabetic KLA patients. Furthermore, the diabetic group showed increased incidences of sepsis and invasive infections, and their length of hospital stay was also prolonged. Pre-incubation of K. pneumoniae in high glucose (0.5%) concentration up-regulated rmpA, ompA, and clbB genes expression. However, cAMP supplementation, which was inhibited by environmental glucose, reversed the increase of rmpA and ompA in a cAMP-dependent manner. Moreover, hvKP strains incubated in high glucose also exhibited enhanced protection from serum killing. High glucose levels reflected by poor glycemic control has increased gene expression of rmpA and ompA in hvKP by the cAMP signaling pathway and enhanced its resistance to serum killing, thus providing a new and reasonable explanation for the high incidences of sepsis and invasive infections in KLA patients with diabetes.

Carbapenem-Resistant Acinetobacter baumannii: Biofilm-Associated Genes, Biofilm-Eradication Potential of Disinfectants, and Biofilm-Inhibitory Effects of Selenium Nanoparticles.

This study aimed to investigate the biofilm-production ability of carbapenem-resistant Acinetobacter baumannii (CRAB), the biofilm-eradication potential of 70% ethanol and 0.5% sodium hypochlorite, the effects of selenium nanoparticles (SeNPs) against planktonic and biofilm-embedded CRAB, and the relationship between biofilm production and bacterial genotypes. A total of 111 CRAB isolates were tested for antimicrobial susceptibility, biofilm formation, presence of the genes encoding carbapenemases, and biofilm-associated virulence factors. The antibiofilm effects of disinfectants and SeNPs against CRAB isolates were also tested. The vast majority of the tested isolates were biofilm producers (91.9%). The bap, ompA, and csuE genes were found in 57%, 70%, and 76% of the CRAB isolates, with the csuE being significantly more common among biofilm producers (78.6%) compared to non-biofilm-producing CRAB (25%). The tested disinfectants showed a better antibiofilm effect on moderate and strong biofilm producers than on weak producers (p &lt; 0.01). The SeNPs showed an inhibitory effect against all tested planktonic (MIC range: 0.00015 to &gt;1.25 mg/mL) and biofilm-embedded CRAB, with a minimum biofilm inhibitory concentration of less than 0.15 mg/mL for 90% of biofilm producers. In conclusion, SeNPs might be used as promising therapeutic and medical device coating agents, thus serving as an alternative approach for the prevention of biofilm-related infections.

Rickettsia spp. in Ticks of South Luangwa Valley, Eastern Province, Zambia

Ticks are important vectors for Rickettsia spp. belonging to the Spotted Fever Group responsible for causing Rickettsiosis worldwide. Rickettsioses pose an underestimated health risk to tourists and local inhabitants. There is evidence of the presence of Rickettsia spp. in Zambia, however there is limited data. A total of 1465 ticks were collected in 20 different locations from dogs and cattle including one cat. Ticks were identified by morphological features or by sequencing of the 16S mitochondrial rRNA gene. Individual ticks were further tested for rickettsiae using a pan-Rickettsia real-time-PCR. Rickettsia species in PCR-positive ticks were identified by sequencing the 23S-5S intergenic spacer region or partial ompA gene, respectively. Seven tick species belonging to three different tick genera were found, namely: Amblyomma variegatum, Rhipicephalus appendiculatus, Rhipicephalus (Boophilus) microplus, Rhipicephalus simus, Rhipicephalus sanguineus, Rhipicephalus zambesiensis and Haemaphysalis elliptica. Out of the 1465 ticks collected, 67 (4.6%) tested positive in the pan-Rickettsia PCR. This study provides detailed data about the presence of Rickettsia species in South Luangwa Valley, Eastern Province, Zambia for the first time. High prevalence of Rickettsia africae in Amblyomma variegatum was found, which indicates the potential risk of infection in the investigated area. Furthermore, to our best knowledge, this is the first time Rickettsia massiliae, a human pathogen causing spotted fever, has been detected in Zambia.

Molecular Detection of Rickettsia and Other Bacteria in Ticks and Birds in an Urban Fragment of Tropical Dry Forest in Magdalena, Colombia.

Birds are important hosts in the life cycle of some species of ticks. In Colombia, there are few eco-epidemiological studies of tick-borne diseases; the existing ones have been focused on areas where unusual outbreaks have occurred. This study describes the identification of ticks collected from birds and vegetation, and the detection of bacteria in those ticks and in blood samples from birds in an urban fragment of tropical dry forest in the department of Magdalena, Colombia. Bird sampling was carried out monthly in 2021, and 367 birds, distributed among 41 species, were captured. All collected ticks were identified as Amblyomma sp. or Amblyomma dissimile. The presence of rickettsiae in ticks collected from birds was evaluated by molecular analysis of the gltA, ompA and sca1 genes. 16S rRNA meta-taxonomy was used to evaluate rickettsiae in ticks collected from vegetation and in blood samples from birds. The presence of the species "Candidatus Rickettsia colombianensi" was detected in ticks from birds. Bacteria of the family Rickettsiacea was the most abundant in ticks collected from vegetation. Bacteria of the families Staphylococcaceae, Comamonadaceae and Pseudomonadaceae were prevalent in the samples of blood from birds. Rickettsia spp. was also detected in low abundance in some of the bird blood samples.

Incidence of virulence genes in predominant Brucella strains among domestic animals in Egypt

To investigate the incidence of the virulence genes among predominant Brucella strains in infected cattle, buffaloes, sheep, goats, and camels as well as in humans in Egypt, a total of 263 samples (85 milk, 167 tissue, 11 whole blood samples), yielded 140 (53.2%) Brucella isolates. Confirmation of Brucella isolates was carried out by conventional biotyping and by PCR using IR1/IR2 primers targeting Brucella genus showing an amplicon of 839 bp in all Brucella isolates. Conventional bioty­ping, as well as duplex PCR of the isolated non-repetitive Brucella strains, identified 107 (76.4 %) as B. melitensis with an amplicon of 731 bp and 33 (23.6%) as B. abortus with an amplicon of 498 bp. Out of 87 Brucella strains isolated from cattle, 63 (72.4%) were B. melitensis. No Brucella isolates were obtained from 7 lymph nodes of camels or 11 human blood samples; however, DNA extraction from 7 human sera and 3 camel lymph nodes gave positive PCR yield. All these samples gave PCR products indicating infection with B. melitensis. The distribution of the virulence genes among 33 B. abortus isolates revealed that virB recorded the highest incidence (97%), then followed bvfA, ure, and omp25 (93.9%), wbkA (90.9%), manB (87.9%) and amiC (84.8%). All 107 B. melitensis isolates had the bvfA, virB, and omp25 genes, while the prevalence of ure was 99.1%, that of wbkA: 96.3%, manB: 95.3% and amiC: 94.4%. The obtained results indicated the high incidence of virulence genes among field Brucella strains among farm animals in Egypt.

Feral pigeons as reservoirs for hazardous Chlamydophila psittaci strains with zoonotic potential

Chlamydophila psittaci is found in pigeons worldwide. The abundance of feral pigeons living in close contact with humans and livestock are considered a significant risk factor for human and farm animal infections. In Iran, little is known about the prevalence of C. psittaci and its genotypes in pigeons. The present cross-sectional study aimed to investigate the prevalence of C. psittaci in feral pigeons and to genotype the detected strains. In total, 384 fresh faecal samples were collected from different areas in Semnan (Iran). Out of all samples, 0.52% were positive for C. psittaci genome in Real Time-PCR. The partial ompA gene sequencing revealed that detected strains were identified as genotypes A and E. This is the first report of C. psittaci genotypes A and E in feral pigeons in Iran. The occurrence of C. psittaci genotypes A and E in the faeces of feral pigeons suggests potential environmental contamination with C. psittaci by pigeons and raise a public health concern.

Antimicrobial resistance and biofilm formation capacity among Acinetobacter baumannii strains isolated from patients with burns and ventilator-associated pneumonia.

Acinetobacter baumannii is a pathogen responsible for nosocomial infections, especially in patients with burns and ventilator-associated pneumonia (VAP). The aims of this study was to compare the biofilm formation capacity, antimicrobial resistance patterns and molecular typing based on PFGE (Pulsed-Field Gel Electrophoresis) in A.baumannii isolated from burn and VAP patients. A total of 50 A.baumannii isolates were obtained from burn and VAP patients. In this study, we assessed antimicrobial susceptibility, biofilm formation capacity, PFGE fingerprinting, and the distribution of biofilm-related genes (csuD, csuE, ptk, ataA, and ompA). Overall, 74% of the strains were multidrug resistant (MDR), and 26% were extensively drug-resistant (XDR). Regarding biofilm formation capacity, 52%, 36%, and 12% of the isolates were strong, moderate, and weak biofilm producers. Strong biofilm formation capacity significantly correlated with XDR phenotype (12/13, 92.3%). All the isolates harbored at least one biofilm-related gene. The most prevalent gene was csuD (98%), followed by ptk (90%), ataA (88%), ompA (86%), and csuE (86%). Harboring all the biofilm-related genes was significantly associated with XDR phenotype. Finally, PFGE clustering revealed 6 clusters, among which cluster No. 2 showed a significant correlation with strong biofilm formation and XDR phenotype. Our findings revealed the variable distribution of biofilm-related genes among MDR and XDR A.baumannii isolates from burn and VAP patients. A significant correlation was found between strong biofilm formation capacity and XDR phenotype. Finally, our results suggested that XDR phenotype was predominant among strong-biofilm producer A.baumannii in our region.