Acta Microbiologica et Immunologica Hungarica

Pediatric Tuberculosis in Mexico and the COVID-19 Phenomenon: Past and Present

2024-01-24T15:02:32+01:00

In endemic zones, tuberculosis in children constitutes a bigger fraction of total cases as compared to those in low endemic zones, regardless of the implications, this phenomenon has been historically neglected. Pediatric tuberculosis has an insidious onset and quickly develops into disseminated disease and the young are at a special risk for dissemination. Some studies suggest that measures to contain adult tuberculosis are not enough to manage tuberculosis in children, meaning that pediatric tuberculosis needs dedicated attention. Children are harder to diagnose than adults, because collecting samples is difficult, and their bacterial yield is low. In endemic countries, such as Mexico, where contact with the bacilli is common, immunological tests are inconsistent, especially in immunocompromised children. With the disruption of Mexican healthcare services by the COVID 19 pandemic, there is uncertainty of how the situation has evolved, current data about tuberculosis indicates a drop in the national report of cases, a small increase in mortality, a drop in treatment success and a decrease in national vaccination rates. There is a need for new research on zones with high tuberculosis incidence to clarify the current situation of pediatric tuberculosis and improve epidemiological surveillance.

Carbapenem-resistant Klebsiella pneumoniae in the Balkans: clonal distribution and associated resistance determinants

2024-01-28T16:16:38+01:00

Carbapenems are considered to be among the last line antibiotic agents against the extended-spectrum β-lactamase-producing Enterobacterales. Carbapenem-resistant Klebsiella pneumoniae’s (CRKP) spread in Europe is indisputable and poses an enormous threat to hospitalized patients which is of growing concern. This review aims to record the prevalence of CRKP in the Balkan region and review the current knowledge upon this life-threatening pathogen. Methods: PubMed and Scopus databases were reviewed by the authors. The time frame was set from 2000 until 2023. The search query included the keywords: “carbapenem”, “resistant”, “klebsiella pneumoniae”, “Greece”, “Croatia”, “Romania”, “Bulgaria”, “Serbia”, “Slovenia”, “Montenegro”, “Bosnia-Herzegovina” and “Albania”. The results were distributed and analyzed for each Balkan country in chronological order. Results: The total number of reposts amounts to 382. After post-screening, the final number of reposts reaches the number 132. Among Balkan countries, Greece and Romania are the ones with the most reports of CRKP. From 2007 until now, KPCs seem to be the dominant carbapenemases in both countries. KPC-2 and NDM-1-producing Klebsiella pneumoniae have been identified as the most frequent carbapenemases in Croatia, Bulgaria, Serbia, and Slovenia. The novel OXA-48 enzyme has been identified in most Balkan countries. Conclusion: CRKP’s emergence poses a severe threat to the Balkan countries. Due to the narrow therapeutic window, it is essential to prevent the spread of multi-resistant Klebsiella pneumoniae strains.

First detection of a cefiderocol-resistant and extensively drug-resistant Acinetobacter baumannii clinical isolate in Bulgaria

2023-12-07T15:22:54+01:00

Cefiderocol (CFDC) is a first-in-class siderophore cephalosporin with potent activity against multidrug-resistant Gram-negative bacteria including carbapenem-resistant Acinetobacter baumannii (CRAB). The present study aimed to explore the CFDC resistance mechanisms of an extensively drug-resistant A. baumannii isolate (XDR-AB) from Bulgaria. Aba52 was obtained in 2018 from a blood sample of a critically ill patient. The methodology included antimicrobial susceptibility testing, whole-genome sequencing (WGS), reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR), multilocus sequence typing, and phylogenomic analysis. Aba52 demonstrated high-level resistance to CFDC (MIC=64 mg/L), resistance to carbapenems, aminoglycosides, fluoroquinolones, sulfamethoxazole-trimethoprim, and tigecycline, as well as susceptibility only to colistin. WGS-based resistome analysis revealed the existence of bla_OXA-23, bla_OXA-66 and bla_ADC-73. Seven non-conservative missense mutations affecting iron transport-related genes were detected: exbD4 (p.Ser61Pro), tonB2 (p.Ala268Val), bauA (p.Thr61Ala), ftsI (p.Ala515Val), piuA (p.Gly216Val), and feoB (p.Ser429Pro and p.Thr595Ala). A variety of virulence factors associated with adherence, biofilm formation, enzyme production, immune invasion, iron uptake, quorum sensing, and two-component regulatory systems were identified, suggesting a significant pathogenic potential of Aba52. The performed RT-qPCR analysis showed diminished (0.17) and absent expression of the pirA and piuA genes, respectively, encoding TonB-dependent siderophore receptors. Aba52 belonged to the widespread high-risk sequence type ST2 (Pasteur scheme). To the best of our knowledge, this is the first documented case of CFDC-resistant A. baumannii in Bulgaria. The emerging resistance, despite CFDC having never been applied in our country, highlights the crucial need for nationwide surveillance targeting the implementation of novel antibiotics.

Outbreak caused by pandrug-resistant blaOXA-69/blaOXA-23/blaGES harboring Acinetobacter baumannii ST2 in an intensive care unit

2023-12-14T12:04:39+01:00

Globally Acinetobacter baumannii has emerged as nosocomial pathogen exhibiting high rates of resistance toward clinically relevant antibiotics. Six PDR-A.b were recovered from three patients in a Tunisian Intensive Care Unit (ICU) between 10^th and 16^th May, 2018, resulting in one death, raising the possibility of an outbreak. On 18^th May, environmental screening was carried out by analyzing different surfaces in the ICU. On 22^thMay, a fourth patient died after contracting PDR-A.b. A second investigation was carried out, with samples taken from various surfaces, and the strain was isolated from the respirator. Antimicrobial susceptibility testing was determined according to EUCAST (2019) guidelines. MIC of colistin was determined by broth dilution method and carbapenemases enzymes screening was performed. PCR was used to detect 14 beta-lactamases/carbapenemases and mcr (mcr-1 to mcr-5) genes. The genetic relatedness of the PDR-A.b isolates was determined by PFGE and MLST. Seven PDR-A.b isolates were recovered from four patients and 3 from: wash basin (an MDR), hand sanitizer bottle (a PDR) and respirator (a PDR). All PDR-A.b isolates (n=9) harbored the bla_OXA-69 gene and none harbored mcr. Moreover, seven carried bla_GES and bla_OXA-23genes. PFGE identified four pulsotypes (A, B, C, and D) with the pulsotype A gathering seven PDR-A.b isolates: five from three patients and one from hygiene sample. MLST revealed that all PDR-A.b isolates of pulsotype A belonged to the pandemic clone ST2. Systematic screening of MDR and PDR-A.b is highly recommended to limit the dissemination of such strains in ICUs.

KPC-2 and VIM-1 producing Klebsiella pneumoniae ST39 high-risk clone isolated from a clinical sample in Volos, Greece

2024-01-20T18:56:38+01:00

Klebsiella pneumoniae is considered to be public health emergence especially due to multidrug resistance. It is largely oligoclonal based on multilocus sequence typing (MLST). In Greece ST39 was detected in 2019, in carbapenem and /or colistin resistant enterobacteriaceae (CCRE) survey. Here we used one strain Kl.pneumoniae ST39 isolated from a blood culture from a patient hospitalized in the I.C.U o Volo’s hospital in November 2020 for Genome sequence utilizing the Ion Torrent platform. Genome sequence was examined for resistance and virulence determinants, capsular types, plasmids, insertion sequences, phage regions, and clustered regularly interspaced palindromic repeats (CRISPR) regions using bioinformatic analysis. The molecular characterization revealed 15 and 50 antimicrobial resistance and virulence genes respectively. Resistance genes such as aac6, bla SHV-40, bla-KPC-2, bla VIM-1, fos-A were mainly responsible for aminoglycosides, b-lactams, carbapenems and fosfomycin resistance respectivel y. The capsular typing revealed that the strain was KL23, O2afg. Replicons were found. Intact phage regions were identified. Our results shed light on critical tasks of mobile genetic elements in ST39 in antibiotic resistance spread.

Investigations of carbapenem resistant and hypervirulent Klebsiella pneumoniae

2023-12-26T16:49:54+01:00

Introduction

Hypervirulent Klebsiella pneumoniae (hvKp) is an emerging strain that is gaining attention due to its increased ability to cause infections even in healthy individuals. The aim of this study is to investigate the presence of virulence factors in K. pneumoniae strains isolated from clinical specimens and their association with carbapenem resistance.

Materials and Method

The study was conducted on 260 isolates identified between 2018 and 2023. The isolates were categorized based on their susceptibility to antibiotics. The hypermucoviscosity was determined by a string test, while the presence of capsular serotypes and virulence genes were identified by PCR.

Results

Among our samples, 6.2% (n=16) exhibited hvKp characteristics, with 56.3% displaying resistance to carbapenem. Notably, 5.7% (n=6) of carbapenem-resistant isolates expressed the hypermucoviscous phenotype, while 1.5% (n=2) of carbapenem-susceptible K. pneumoniae isolates exhibited the same trait. In our study we found that a total of 10 isolates (3.8%) had virulent capsular serotypes with K2 being the most prevalent 40% (n=4) and K20 in 30% (n=3). Furthermore we detected the presence of the Aerobactin gene in 1.5% (n=4) of the isolates examined. Based on our findings, it appears that there was no correlation between the presence of virulence factors and carbapenem resistance.

Conclusion

Identifying hvKp strains in clinical specimens and assessing their antibiotic resistance profiles are crucial for ensuring efficacious therapy and preventing potential epidemics.

High rates of intestinal colonization with carbapenemase producing Enterobacteriaceae in hematopoietic stem cell transplant recipients

2024-01-05T10:06:31+01:00

Introduction: Carbapenem resistant Enterobacteriaceae (CRE) are feared because they generate therapeutic difficulties, and they have an important epidemic power. Allogeneic hematopoietic stem cell transplant (AHSCT) recipients are highly exposed to this type of bacteria. The aim of our study was to investigate the prevalence of CRE colonization in AHSCT patients at the National Bone Marrow Transplant Centre (NBMTC) and to determine genes encoding carbapenem resistance.

Methods: A retrospective study conducted between January 2015 and December 2019, involved 55 patients colonized with CRE strains. We determined the rate of antibiotic resistance according to the standards of the French Antibiotic Committee and the carbapenem resistance genes by PCR assays for genes encoding the most frequent β-lactamase: class A, B and D carbapenemases.

Results: Eighty-one episodes of CRE colonization were recorded in 55 patients (26.1% of total AHSCT recipients), mainly suffering from acute leukemia (30%) and aplastic anemia (26%). History of hospitalization in the previous three months was noted in 80 episodes (99%). Prior antibiotherapy, severe neutropenia and corticosteroid therapy were respectively found in 94%, 76% and 58% of cases. Among the 55 patients, six patients (11%) developed a CRE infection. The infections were bacteremia (n=4), urinary tract infection (n=1) and respiratory infection (n=1). One patient among the six infected died after a carbapenem-resistant Klebsiella pneumoniae bacteremia. The CRE responsible for colonization were essentially found in the stools (85%). They were carbapenemase producers in 90% of cases. They belonged mostly to K. pneumoniae (61/81) and E. coli species (10/81). Antibiotic resistance rates were 100% for ertapenem, 53% for imipenem, 42% for amikacin, 88% for ciprofloxacin and 27% for fosfomycin. The molecular study showed that the blaOXA48 gene was the most frequent (n=49, 60.5%), followed by blaNDM (47 strains, 58%). Thirty-five (43%) strains were coproducers of carbapenemase. The most frequent genotype was bla_OXA48+bla_NDM (19 strains).

Conclusion: Hight rate of CRE colonization and high rate of coproduction of carbapenemase in AHSCT recipients in our center.

Prevalence and antimicrobial resistance of bacterial enteropathogens in Crete, Greece, during 2011-2022

2024-01-15T13:33:59+01:00

Diarrheal diseases are of great concern worldwide and are responsible for considerable morbidity and mortality. This study investigated the epidemiology and susceptibility of bacterial enteropathogens among diarrheal patients of all ages in Crete, Greece during 2011-2022. Stool specimens were tested by conventional cultural methods for Salmonella, Shigella, Campylobacter, diarrheagenic Escherichia coli (EPEC, STEC), Yersinia, Aeromonas species and Clostridium difficile. Antimicrobial susceptibility was determined using the disk diffusion method for Enterobacterales, Campylobacter and Aeromonas, and by the gradient diffusion method for C. difficile. Of the 26,060 stool samples from patients of any age, 1,022 (3.9%) were positive for bacterial enteropathogens. Campylobacter spp. were the most commonly isolated bacteria (56.4%), followed by Salmonella enterica (32.3%), and E. coli (6.5%). Toxigenic Clostridium difficile was isolated from 341 out of 8,848 diarrhoeal specimens examined (3.9%). Resistance to ampicillin was observed in 12.4% of the Salmonella, 66.7% of the Shigella and 34.8% of the E. coli isolates. Resistance to trimethoprim-sulfamethoxazole was observed in 5.8% of the Salmonella, 33.3% of the Shigella, and 15.1% of the E. coli isolates. High rates of ciprofloxacin resistance (77.3%) were detected among Campylobacter isolates, while resistance to erythromycin was observed in 2.4% of them. All C. difficile isolates were susceptible to vancomycin and metronidazole. Our findings suggest declining trends in the prevalence of bacterial enteropathogens, except for Campylobacter spp. and changes in the susceptibility rates to antimicrobials. Continous surveillance of the prevalence and antimicrobial susceptibility of bacterial enteropathogens is mandatory for implementing targeted and effective prevention and infection control measures.

Occupational exposure to Coxiella burnetii during cardiac surgery: a case report and review of the literature.

2024-02-07T09:58:08+01:00

We report a case of exposure to Coxiella burnetti in a surgical nurse who underwent an injury of her finger with a scalpel blade during a native aortic valve replacement with a bio-prosthetic valve cardiac conducted on a patient suffering from C. burnetii aortic endocarditis. Given the positivity of C. burnetii culture and PCR from the patient’s aortic valve, she was prescribed prophylactic doxycycline 100 mg twice a day for 10 days. Q fever is an occupational zoonosis resulting usually of exposure to infected animals by inhalation of infected aerosols or consumption of contaminated raw milk. Apart from materno-foetal transmission, about 180 cases of human-to-human C. burnetii transmission have been published from 1949 to today, including transmission by blood transfusion, sexual relations, transmission in the health care setting to staff, other patients or patient attendants that likely resulted from inhalation of aerosol from respiratory or placental products, transmission to staff during autopsies of patients with Q fever and transmission in familial settings. As C. burnetii is a highly infectious bacterium that may cause infection with a low inoculum, it should be added to the list of organism which may be of concern following blood exposure among health care professionals.

Antibiotic resistance and genomic characterization of Mycobacterium abscessus complex isolates from patients with pulmonary tuberculosis in Iran: A multi-center study (2010-2021)

2023-12-24T11:21:46+01:00

One hundred and eighteen sputum specimens suspected of M. abscessus complex infection were collected. rpoB sequencing amplification for species level of M. abscessus. MLST typing for M. abscessus. Clarithromycin, Amikacin, ciprofloxacin, and moxifloxacin susceptibility testing were performed. All 128 isolates were subjected to rpoB gene sequencing for definite identification. Among 128 specimens, 59 specimens were definitely identified as M.abscessus 59 specimens that were definitely by the rpoB gene included M. abscessus subsp. 22(37.28%), M. abscessus subsp. M. massiliense 22 isolates (37.28%), and M. abscessus subsp. M. bolletii 15 (25.42%) isolates. In MLST analysis, several isolates were typed two or three times during the study, and the results were confirmed. ST40s were identified among the 54 isolates and were specific for each subspecies. Two STs were specific to M. abscessus subsp. abscessus, 1 was specific to M. abscessus subsp. bolletii, and one 1 was specific to M. abscessus subsp. Massiliense. In antibiotic resistance, clarithromycin susceptibility testing of 22 M. abscessus subsp. M. abscessus strains identified 15(68.18%) resistant strains, 22 M. Massiliense 5 (22.72%), and 15 bolletii5(22.72%) resistant strains. Our study revealed a significant level of antibiotic resistance in isolates of the M. abscessus complex, which has the potential to be life-threatening

Phylogenetic analysis and antimony resistance of Leishmania major isolated from humans and rodents

2024-02-24T17:23:10+01:00

ABSTRACT

Background: Cutaneous leishmaniasis (CL) is one of the world’s neglected disease which is caused by Leishmania spp. The aim of the present was to assess the molecular profile and antimony resistance of Leishmania major isolated of human and rodent hosts.

Methods: The samples were collected from suspected CL patients referred to health centers and the wild rodent's traps in Gonbad-e-Qabus region, Iran. The smears were both subjected to the PCR-RFLP to the identification of Leishmania species. In addition, the ITS1-PCR products were sequenced for phylogenetic analysis. Also, the expression levels of the antimony resistance-related genes were determined in CL isolates.

Results: Out of 1,949 suspected patients with CL and 148 rodents, 1,704 (87.4%) and 6 (4.05%) were positive with direct smear, respectively. The phylogenic analysis revealed the highest interspecies similarity was found between current L. major sequences with L. major obtained from Russia and Uzbekistan. In vitro susceptibility assay of 20 unresponsive and 20 responsive to meglumine antimoniate treatment demonstrated a potent correlation between the clinical treatment outcome and resistance cases.

Conclusion: Herein we unequivocally demonstrate the genetic diversity and antimony resistance of L. major isolated from human and reservoir hosts in the north-eastern Iran, which could be the basis for planning future control strategies.