The Role of nmcR, ampR, and ampD in the Regulation of the Class A Carbapenemase NmcA in Enterobacter ludwigii

Various carbapenemases have been identified in the Enterobacteriaceae. However, the induction and corresponding regulator genes of carbapenemase NmcA has rarely been detected in the Enterobacter cloacae complex (ECC). The NmcA-positive isolate ECC NR1491 was first detected in Japan in 2013. It was characterized and its induction system elucidated by evaluating its associated regulator genes nmcR, ampD, and ampR. The isolate was highly resistant to all β-lactams except for third generation cephalosporins (3GC). Whole-genome analysis revealed that blaNmcA was located on a novel 29-kb putatively mobile element called EludIMEX-1 inserted into the chromosome. The inducibility of β-lactamase activity by various agents was evaluated. Cefoxitin was confirmed as a strong concentration-independent β-lactamase inducer. In contrast, carbapenems induced β-lactamase in a concentration-dependent manner. All selected 3GC-mutants harboring substitutions on ampD (as ampR and nmcR were unchanged) were highly resistant to 3GC. The ampD mutant strain NR3901 presented with a 700 × increase in β-lactamase activity with or without induction. Similar upregulation was also observed for ampC and nmcA. NR1491 (pKU412) was obtained by transforming the ampR mutant (135Asn) clone plasmid whose expression increased by ∼100×. Like NR3901, it was highly resistant to 3GC. Overexpression of ampC, rather than nmcA, may have accounted for the higher MIC in NR1491. The ampR mutant repressed nmcA despite induction and it remains unclear how it stimulates nmcA transcription via induction. Future experiments should analyze the roles of nmcR mutant strains.

The Overlooked Issue of Outpatient Combination Antibiotic Prescribing in Low- and Middle-Income Countries: An Example from Syria

This study aimed to determine and describe the prevalence of combination antibiotics dispensed in outpatients with health insurance in Syria. Data on all dispensed medicines between June 2018 and May 2019 for 81,314 adults were obtained, and medicines belonging to the J01 group of the World Health Organization (WHO) anatomical therapeutic classification (ATC) were included in the analysis. Prescriptions were stratified according to the number of antibiotics, age, and sex. Antibiotic utilization was expressed as the number of prescriptions per 1000 persons per year. Out of 59,404 prescriptions for antibiotics, 14.98% contained antibiotic combinations, distributed to 22.49% of the patients. The prevalence of dispensing antibiotic combinations was higher in female patients (23.00%), and the youngest (18–30 years, 26.19%) and oldest age groups (>70 years, 25.19%). The antibiotics most commonly combined were co-amoxiclav, second- and third-generation cephalosporins, and macrolides. Over 60% of the combinations contained ceftriaxone alone or in combination with sulbactam. The present study shows an alarmingly widespread prescription of antibiotic combinations, posing a risk to global health by promoting resistance development.

Kajian Penggunaan Antibiotik pada Pasien Meningitis dan Ensefalitis Bakteri di Bangsal Rawat Inap Rumah Sakit Rujukan Utama

Inadequate antibiotic therapy for meningitis and bacterial encephalitis is one of the factors that can jeopardize patient safety and turn into a public health issue in a number of nations, including Indonesia. This phenomena has the potential to raise health-care expenses, which should be avoided in the era of the JKN program's implementation. The goal of this research was to describe the profile of antibiotic use and cost in hospitalized meningitis and bacterial encephalitis patients. This cross-sectional observational study took place from January to December 2019. As study materials, patient medical records and billing data were employed. To enhance the data obtained, confirmation with medical and pharmaceutical personnel is required. Antibiotic use and expenditures were described using descriptive analysis. A total of 71 patients, both children and adults, met the study's inclusion criteria. Antibiotics were given to all of the patients, and the results revealed that third generation cephalosporins (49.375%) were the most commonly recommended antibiotic class, either alone or in combination. Antibiotic use receives 46.94% of total medication funding. According to the length of stay category, the majority of patients (45.99 %) were hospitalized for 8-14 days consecutively with antibiotic medication. Antibiotics, which are typically administered to patients with meningitis and bacterial encephalitis, had no effect on the length of stay in the hospital. Antibiotic prescriptions must be carefully reviewed at top referrel hospital, taking into account the local germ map.

Antibiotic Prescribing Patterns in Paediatric Primary Care in Italy: Findings from 2012–2018

Comprehensive data are needed to monitor antibiotic prescribing and inform stewardship. We aimed to evaluate the current antibiotic prescribing patterns, including treatment switching and prolongation, in the paediatric primary care setting in Italy. This database study assessed antibiotic prescriptions retrieved from Pedianet, a paediatric primary care database, from 1 January 2012 to 31 December 2018. Descriptive analyses were stratified by diagnosis class, calendar year, and children’s age. Generalized linear Poisson regression was used to assess variation in the prescriptions. In total, 505,927 antibiotic prescriptions were included. From 2012 to 2018, the number of antibiotics per child decreased significantly by 4% yearly from 0.79 in 2012 to 0.62 in 2018. Amoxicillin prescriptions decreased with increasing children’s age, while macrolides and third-generation cephalosporins had the opposite trend. Prescriptions were associated with a diagnosis of upper respiratory infection in 23% of cases, followed by pharyngitis (21%), bronchitis and bronchiolitis (12%), and acute otitis media (12%). Eight percent of treatment episodes were prolonged or switched class, mostly represented by co-amoxiclav, macrolides, and third-generation cephalosporins. Our findings report an overall decrease in antibiotic prescriptions, but pre-schoolers are still receiving more than one antibiotic yearly, and broad-spectrum antibiotics prescription rates remain the highest.

Resistance pattern of infected chronic wound isolates and factors associated with bacterial resistance to third generation cephalosporins at Mbarara Regional Referral Hospital, Uganda

Background The objectives of this study were; (I) to determine the proportion of pathogens isolated from patients with infected chronic wounds in the surgical ward of MRRH that are resistant to the third-generation cephalosporins and (II) to determine the factors associated with resistance to third-generation cephalosporins in the surgical ward of MRRH. Method(s) This study was a descriptive analytical survey of bacterial isolates from infected chronic wounds among patients admitted in the surgical ward of MRRH, Uganda. Seventy five (75) study participants were recruited in the study using convenient sampling technique. Bacterial culture and identification was performed using standard microbiology laboratory procedures whereas broth microdilution method was used to establish the susceptibility of the identified pathogens. Data for objective one (1) was summarized as proportions while the categorized variables were analyzed using logistic regression to determine whether they were associated with the resistance patterns. The level of significance was preset at 5% and p-values less than 0.05 were considered statistically significant. Results Generally, all isolates had complete susceptibility (100%) to Cefoperazone+Sulbactam 2g except 7.1% of proteus spp that were resistant. Of all the bacterial isolates studied, Staphylococcus aureus, Enterobacter agglomerans, providencia spp and pseudomonas earuginosa had complete resistance (100%) to Cefopodoxime 200mg while providencia spp and pseudomomas earuginosa had complete resistance (100%) to Cefixime 400mg and cefotaxime 1g. Finally, higher odds of bacterial resistance to more 2 brands of the third generation cephalosporins were observed among participants who had prior exposure to the third generation cephalosporins (OR, 2.22, 95% CI, 0.80–6.14), comorbidities (OR, 1.76, 95% CI, 0.62–4.96) and those who had more than two hospitalizations in a year (OR, 1.39, 95% CI 0.46–4.25). However, multivariate logistic regression was not performed since no factor was significantly associated with resistance to more than two brands of third generation cephalosporins (p >0.05). Conclusion This study found that cefixime and cefpodoixme had high rates of resistance and should not be used in routine management of infected chronic wounds. In addition, the factors investigated in this study were not significantly associated with bacterial resistance to more than two brands of third generation cephalosporins.

Presence of the Extended-Spectrum-β-Lactamase and Plasmid-Mediated AmpC-Encoding Genes in Escherichia coli from Companion Animals—A Study from a University-Based Veterinary Hospital in Taipei, Taiwan

Extended-spectrum-β-lactamase (ESBL) and AmpC β-lactamase are two enzymes commonly found in Enterobacteriaceae that confer resistance to major antibiotics, such as third-generation cephalosporins that are widely prescribed for both human and animals. We screened for Escherichia coli producing ESBL and plasmid-mediated AmpC β-lactamase (pAmpC) from dogs and cats brought to National Taiwan University Veterinary Hospital, Taipei, Taiwan from 29 June 2020, to 31 December 2020. The genotypes and phylogenetic relatedness of these E. coli were also analyzed. Fifty samples of E. coli obtained from 249 bacterial isolates were included in this study. Among them, eight isolates had ESBL, seven had pAmpC, and one had both. Thirty-two percent (16/50) of E. coli isolates were resistant to third-generation cephalosporins. The detected ESBL genes included the blaCTX-M-1 and blaCTX-M-9 groups, and the blaCMY-2 group was the only gene type found in pAmpC. ESBL-producing E. coli belonged to the pathogenic phylogroup B2, and the sequence types (STs) were ST131 and ST1193. Three isolates were determined to be ST131-O25b, a highly virulent epidemic clone. The pAmpC-producing E. coli were distributed in multiple phylogroups, primarily the commensal phylogroup B1. The STs of the pAmpC-producing E. coli included ST155, ST315, ST617, ST457, ST767, ST372, and ST93; all of these have been reported in humans and animals. Imipenem was active against all the ESBL/pAmpC-producing E. coli; however, since in humans it is a last-resort antimicrobial, its use in companion animals should be restricted.

AmpC cephalosporinases in Escherichia coli

Escherichia coli is an important pathogen causing nosocomial infections. A significant problem in the treatment of infections caused by these microorganisms is their increasing resistance to β-lactam antibiotics, including third and fourth generation cephalosporins. The production of β-lactamases enzymes such as extended-spectrum β-lactamases (ESBLs) and AmpC β-lactamases is among the main mechanisms for resistance to third generation cephalosporins. The genes encoding AmpC cephalosporinases are chromosomal (cAmpC) or plasmid-mediated (pAmpC). In E. coli, the expression of the ampC genes may be conditioned by the constitutive expression of low level ampC chromosomal genes. These strains remain susceptible to β-lactam antibiotics. However, mutations in the promoter region of the ampC may result in increased level of expression of chromosomal ampC genes. This can leads to resistance to cephalosporins. Resistance to cephalosporins in E. coli can be also associated with plasmid-mediated AmpC β−lactamases (pAmpC). In E. coli the presence of one or more plasmid-mediated AmpC β−lactamases along with the neglible expression of chromosomal encoded AmpC enzyme can leads to resistance to broad-spectrum cephalosporins. This review is focused on a resistance mechanisms associated with the production of AmpC cephalosporinases in clinical E. coli isolates.

When first line treatment of neonatal infection is not enough: blood culture and resistance patterns in neonates requiring second line antibiotic therapy in Bangui, Central African Republic

Background Infectious diseases account for the third most common cause of neonatal deaths. Globally, antibiotic resistance (ABR) has been increasingly challenging neonatal sepsis treatment, with 26 to 84% of gram-negative bacteria resistant to third-generation cephalosporins. In sub-Saharan Africa, limited evidence is available regarding the neonatal microbiology and ABR. To our knowledge, no studies have assessed neonatal bacterial infections and ABR in Central-African Republic (CAR). Therefore, this study aimed to describe the pathogens isolated and their specific ABR among patients with suspected antibiotic-resistant neonatal infection admitted in a CAR neonatal unit. Methods This retrospective cohort study included neonates admitted in the neonatal unit in Bangui, CAR, from December 2018 to March 2020, with suspected antibiotic-resistant neonatal infection and subsequent blood culture. We described the frequency of pathogens isolated from blood cultures, their ABR prevalence, and factors associated with fatal outcome. Results Blood cultures were positive in 33 (26.6%) of 124 patients tested (17.9% for early-onset and 46.3% for late-onset infection; p = 0.002). Gram-negative bacteria were isolated in 87.9% of positive samples; with most frequently isolated bacteria being Klebsiella pneumoniae (39.4%), Escherichia coli (21.2%) and Klebsiella oxytoca (18.2%). All tested bacteria were resistant to ampicillin. Resistance to third-generation cephalosporins was observed in 100% of tested Klebsiella pneumoniae, 83.3% of isolated Klebsiella oxytoca and 50.0% of tested Escherichia coli. None of the tested bacteria were resistant to carbapenems. Approximately 85.7 and 77.8% of gram-negative tested bacteria were resistant to first-line (ampicillin-gentamicin) and second-line (third-generation cephalosporins) treatments, respectively. In hospital mortality, adjusted for blood culture result, presence of asphyxia, birth weight and sex was higher among neonates with positive blood culture (adjusted relative risk [aRR] = 2.32; 95% confidence interval [CI] = 1.17–4.60), male sex (aRR = 2.07; 95% CI = 1.01–4.26), asphyxia (aRR = 2.42; 95% CI = 1.07–5.47) and very low birth weight (1000–1499 g) (aRR = 2.74; 95% CI = 1.3–5.79). Conclusion Overall, 77.8% of confirmed gram-negative neonatal infections could no longer effectively be treated without broad-spectrum antibiotics that are not routinely used in sub-Saharan Africa referral hospitals. Carbapenems should be considered an option in hospitals with surveillance and antibiotic stewardship.