Drug Resistance Patterns Research Articles

Patterns of Drug Resistance and Bacterial Pathogen Distribution in Patients with Urinary Tract Infections in the Jiaxing Region from 2020 to 2022.

Urinary tract infections (UTIs) and the antibiotic resistance of pathogenic bacteria pose severe threats to public health in the current healthcare environment. The purpose of this study was to assess the frequency distribution of bacterial pathogens causing UTIs as well as the characteristics of antibiotic susceptibility and resistance. The retrospective study was conducted on 32,391 samples of midstream urine culture from January 1, 2020, to December 31, 2022, in Jiaxing. Bacteria were cultivated on blood agar and identified using MALDI-TOF, and their susceptibility to different antibiotics was assessed using the Kirby-Bauer disk diffusion method and drug sensitivity reaction cards. The SPSS 22 software was used for data analysis. Bivariate logistic regression was used to analyze the risk factors for multidrug resistance. The total number of positive growth samples was 5378 (16.6%), including 3206 females (59.6%) and 2172 males (40.4%). The four most common urinary pathogens were Escherichia coli (39.2%), Enterococcus faecalis (12.4%), Klebsiella pneumoniae (7.6%), and Enterococcus faecium (7.6%). As far as antibiotic resistance was concerned, Escherichia coli had a greater than 50% resistance rate to ampicillin (76.1%), ciprofloxacin (58.6%), and levofloxacin (51.2%). The multidrug resistance rate was high (41.8%). Low levels of resistance were seen to ertapenem (0.1%), imipenem (0.7%), meropenem (0.7%), piperacillin/tazobactam (0.7%), and nitrofurantoin (1.8%). Klebsiella pneumoniae was highly sensitive to ertapenem (100%). The resistance rates to nitrofurantoin, ceftriaxone, and ciprofloxacin were 37.4%, 37.1%, and 35.1%, respectively. Up to 41% of Escherichia coli strains and 26% of Klebsiella pneumoniae strains produced extended-spectrum lactamases (ESBL). Two species of enterococci were highly sensitive to tigecycline and linezolid (100%), and a small number of norvancomycin-resistant strains (0.2%/two strains) were found. Escherichia coli and Enterococcus faecium were the most common urinary pathogens in this study. The isolated pathogens showed different sensitivity patterns. Antibiotics should be selected reasonably according to the sensitivity mode of pathogenic bacteria to effectively treat and prevent urinary tract infections.

Multidrug-Resistant Staphylococcus capitis: An Emerging Challenge in Clinical Settings Found in Adult Patients in Saudi Arabia

The study reveals crucial information on S. capitis, a potentially dangerous bacterium that can cause sepsis in hospitalized adult patients, including its frequency and patterns of drug resistance which could significantly contribute to the existing body of knowledge in this field. This retrospective study was conducted in the King Fahad Medical City (KFMC), Riyadh, Saudi Arabia, from June 2019 to November 2022. The comprehensive data collection and analysis provide valuable information on the prevalence of S. capitis in different infection sites, antibiotic sensitivity profiles, and the association with patient demographics. A total of 219 S. capitis isolates from hospitalized patients with sepsis tested positive. Infection was most common in venous blood (139 patients, 63.5%), followed by central blood (24 patients, 11%). Other locations included venipuncture (48 patients, 21.9%) and cerebrospinal fluid (three patients, 1.4%). The results highlight the clinical significance of S. capitis as a major contributor to sepsis, especially in male patients, and emphasize the need for appropriate antibiotic selection for effective treatment. Furthermore, this study raises concerns about the high rates of methicillin resistance observed in S. capitis isolates, emphasizing the urgency in tackling antibiotic resistance and promoting judicious antibiotic prescription practices. Moreover, the identification of a decreased susceptibility to vancomycin as a potential explanation for its reduced effectiveness in treating S. capitis infections adds a crucial aspect to the discussion of treatment options and underscores the need for alternative therapeutic strategies.

Structural characterization, antioxidant and anti-uropathogenic potential of biogenic silver nanoparticles using brown seaweed Turbinaria ornata.

Alternative treatment strategies for urinary tract infections (UTIs) are becoming more necessary due to increasing drug resistance patterns in uropathogens. Nanoparticle-based therapeutics is emerging as a way to treat UTIs. In the present study, using Turbinaria ornata extract, silver nanoparticles (AgNPs) were synthesized, characterized, and their anti-uropathogenic activity was evaluated. The stability and formation of synthesized To-AgNPs were confirmed by UV-visible spectroscopy, FTIR, XRD, SEM, and DLS. An FTIR spectrum confirmed the presence of seaweed functional groups in To-AgNPs, a XRD analysis confirmed their crystalline nature, and SEM imaging confirmed their spherical nature with an average size of 73.98 nm with diameters ranging from 64.67 to 81.28 nm. This was confirmed by TEM results. DLS determined that the cumulant hydrodynamic diameter of To-AgNPs was 128.3 nm with a PdI of 0.313 and the zeta potential value were found to be -63.3 mV which indicates the To-AgNPs are negatively charged and more stable. DPPH assays were used to assess the antioxidant activity of biosynthesized To-AgNPs, while an agar well diffusion method was used to test the antibacterial activity against uropathogens, including Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, and Klebsiella pneumoniae. The To-AgNPs showed the highest susceptibility to S. aureus (15.75 ± 0.35 mm) and E. coli (15 ± 0.7 mm) with MIC values of 0.0625 and 0.125 mg/ml, respectively in macro broth dilution method and observed considerable membrane damage under CLSM and SEM. To-AgNPs displayed stronger antioxidant and antimicrobial activity, suggesting they may be developed as a new class of antimicrobial agents for treating UTIs.

Molecular diversity of Mycobacterium tuberculosis isolates in Treatment-experienced Patients from Andhra Pradesh, India.

To get a comprehensive idea about the transmission and epidemiology of TB globally and locally, the use of molecular typing methods has become imperative not only for understanding genetic diversity but also the population structure of Mycobacterium tuberculosis complex (MTBC). We aimed to investigate the drug resistance pattern and genetic diversity of MTBC among previously treated patients with sputum smear-positive pulmonary tuberculosis in a South Indian population. 104 patients with sputum smear positivity and who had previously undergone treatment were selected. Drug susceptibility testing, Spoligotyping, MIRU-VNTR, and SNP typing were performed. Mono-resistance to isoniazid 16 (15.38%) was the highest among all drugs. Out of 104 isolates, 24 (23%) isolates were classified as MDR strains. The distributions of most common lineages were: EAI3-Ind-20 (19.23%), EAI5-13 (12.50%), Beijing-12 (11.54%), CAS1-Delhi- 9 (8.65%), and 7 (6.73%) each of T-H37rv, Unknown and Orphan types. MIRU-VNTR-based analysis revealed that there are two major groups: CAS1-Delhi and Beijing groups. Out of 104 isolates, 82 belonged to well-defined lineages and 6 clusters, and the remaining 22 were singletons. SNP analysis showed no mutations associated with five sets of genes in 33 strains. The occurrence of 11.54% Beijing strains in South India is an important finding. High frequency of Isoniazid mono resistance noticed. Spoligotyping along with MIRU-VNTR and SNP typing is the best approach to the identification of strain lineages. No mutation with Antigen85C gene represents, can be used for vaccine candidates.

The impact of the COVID-19 pandemic on gram-negative bacteria susceptibility patterns in respiratory samples of intensive care units in the Brussels Capital Region, 2010-2021

The effect of the Coronavirus Disease 2019 (COVID-19) pandemic on gram-negative bacterianonsusceptibility to antibiotics is unclear. Between January 1, 2010, and December 31, 2021, the respiratory samples of intensive care unit patients at 3 University Hospitals in Brussels were retrieved. Based on the nonsusceptibility to antimicrobial classes, drug-resistance patterns were defined as multi-drug-resistant, extensively drug-resistant, and pan-drug-resistant. The study time frame was divided into 6 periods of 2 years each, and the impact of the COVID-19 pandemic (last period: 2020-2021) was assessed. During the current study, 10,577 samples were identified from 5,889 patients. While a significant augmentation of multi-drug-resistant isolates was noticed once comparing 2 prepandemic periods (2012-2013 and 2014-2015), all 3 patterns of nonsusceptibility significantly increased, comparing the years before and throughout the COVID-19 pandemic (2018-2019 and 2020-2021). Globally, the greatest increase in antimicrobial nonsusceptibility, comparing the last 2 periods, was reported for piperacillin-tazobactam (from 28% to 38%). Pseudomonas aeruginosa was the most isolated species, and the most involved in the appearance of resistance, with an augmentation of nonsusceptibility percentage to meropenem of 22% (from 25% to 47%), between the prepandemic and the pandemic periods. The COVID-19 pandemic was associated with increasing trends of antimicrobial resistance in respiratory samples of patients admitted to the intensive care units in university hospitals with well-implemented antibiotic stewardship programs.

Research Note: Changes in pathogenic characteristics and drug resistance of Salmonella in poultry meat in Jiading District, Shanghai from 2019 to 2021

To investigate the contamination status, serotype distribution, and drug resistance of Salmonella in poultry sold in Jiading District, Shanghai. Four types of raw poultry meats (chickens, ducks, geese, and pigeons) have been sampled from commercial markets, and potential Salmonella contamination has also been isolated and identified via serotype analysis. Furthermore, resistance of isolated Salmonella toward 14 commonly used antibiotics has also been conducted. Ninety-two Salmonella strains were isolated from 236 commercial poultry samples. The detection rates of Salmonella in pigeon, goose, duck, and chicken were 28.89, 44.44, 39.34, and 38.30%, respectively. The detection rate of Salmonella exhibits considerable variation across different years. The serotype composition of Salmonella in poultry demonstrates annual variability, undergoing significant changes from year to year. The majority serotypes of Salmonella have been revealed as S. Typhimurium, S. Enteritidis, and S. Agona. Relatively higher drug resistance was discovered with nalidixic acid, tetracycline, ampicillin and chloramphenicol, with drug resistance rate as 58.70, 53.25, 44.57, and 38.04%, respectively. Low drug resistance was revealed with cefotaxime, and completely sensitive to imipenem. Significant difference in drug resistance was noted in the Salmonella isolated from meats. Different serotypes of Salmonella strains have also revealed as difference in drug resistance. A total of 15.22% of Salmonella strains were nonresistant to any tested drugs. Multidrug-resistant strains accounted for 36.96% of isolated strains. The highest number of resistant antibiotics can reach 12 kinds of different antibiotics, Salmonella resistance is exhibiting a consistent upward trend overall. AMP-TET or CHL-CFZ drug resistance pattern suggested that the strain was multidrug resistant. The contamination of Salmonella in raw poultry meat samples in Jiading District, Shanghai is serious, and the drug resistance is increasing. The measures taken for epidemic prevention and control have a certain impact on the contamination of Salmonella in poultry meat. Therefore, monitoring and control should be strengthened.

Clinical and microbiology profile of typhoidal and nontyphoidal Salmonella blood stream infection: An observational study from a university hospital

Objectives: Species distribution and antibiotic resistance pattern of Salmonella varies with time and place. Rapid and correct use of antibiotics requires understanding of the distribution and drug resistance patterns. Therefore, we aimed to study the clinical profile of patients along with speciation and antibiogram of Salmonella isolates from blood. Materials and Methods: It is an observational study, conducted from December 2019 to December 2021 at our university hospital. Blood cultures were processed by automated blood culture system. Salmonella isolates were identified by their morphological properties, biochemical reaction, and serological tests. Antibiotic susceptibility pattern was assessed by Kirby–Bauer’s disc diffusion method and Phoenix automated system. Results: The male-to-female ratio of the patients in the study was 2.5:1 and the mean age of the patients was 11.7 years (1–27 years). Salmonella spp. was isolated from 21 patients out of 1,350 positive blood cultures. Nine isolates were identified as S. Typhi seven as S. Choleraesuis three as S. Paratyphi A and two as S. Paratyphi B. Immuno-compromised conditions were significantly associated in nontyphoidal Salmonella bacteremia (p = 0.0253). Isolates showed maximum resistance toward nalidixic acid (100%) followed by fluoroquinolones (52.4%). Multidrug resistance, extreme drug resistance, and azithromycin resistance was seen in 14.3, 4.8, and 4.8% isolates, respectively. Posttreatment recovery was observed in 20 patients. Conclusions: Emergence of S. Choleraesuis among Salmonella spp. in blood stream infection, next only to S. Typhi was noted. Rising drug resistance is a matter of concern.

Phenotypic Drug Resistance Pattern and Mutation Characteristics of Mycobacterium tuberculosis from Different Body Fluids Among Extra Pulmonary Patients Presented in Selected Hospitals in Addis Ababa, Ethiopia.

Drug resistance in tuberculosis poses challenges to both the control and prevention of the disease. The extent of resistance is not well known in developing countries, including Ethiopia. This study was conducted to determine the drug resistance patterns and mutation characteristics of Mycobacterium tuberculosis among extra pulmonary tuberculosis patients in selected health facilities in Addis Ababa. A cross-sectional study was conducted from February 2022 to August 2022 in selected hospitals in Addis Ababa. Socio-demographic and clinical data were collected using structured questionnaire. Mycobacterium tuberculosis complex (MTBC) isolates were tested for phenotypic drug susceptibility patterns using the Mycobacterium growth indicator tube (MGIT) method for first-line drugs and mutation characteristics using the Line Probe Assay (LPA) method. The data were analyzed using: SPSS version 23, and a P-value ≤ 0.05 was considered statistically significant. From a total of 308 patient samples from presumptive extra pulmonary patients, 44 (14.3%) were positive for MTBC. Any drug resistance was discovered in 25% of 44 MTBC isolates evaluated for five first-line drugs phenotypically, with isoniazid (INH) and pyrazinamide (PZA) resistance accounting for a greater proportion with 13.6% and 11.4% of the isolates, respectively. Two (4.5%) of the isolates were MDR-TB. Out of 44 isolates tested using the Geno Type MTBDRplus assay, 5 (11.4%) showed mutations at katG and 2 (4.5%) showed mutations in the rpoB genes. Both the phenotypic and genotypic drug susceptibility test results showed a high proportion of INH resistance. All INH resistance-conferring mutations were identified from katG gene. The overall prevalence of MDR-TB was also high. For early case detection and treatment, expanding diagnostic capacity for first-line DST is a vital step to limit further spread of drug resistant TB strains in the study area.

A pattern of antibiotic drug resistance of Salmonella Typhi and Salmonella Paratyphi among children with enteric fever in a tertiary care hospital in Lahore, Pakistan

A pattern of antibiotic drug resistance of Salmonella Typhi and Salmonella Paratyphi among children with enteric fever in a tertiary care hospital in Lahore, Pakistan

Patterns of HIV-1 drug resistance among HIV-infected patients receiving first-line antiretroviral therapy in Novosibirsk Region, Russia

Antiretroviral (ARV) drugs have played a vital role in controlling the HIV-1 epidemic; however, some challenges remain. ARV drugs vary in their ability to control HIV infection, displaying differences in treatment-limiting factors and genetic barriers to resistance. The current report assesses the prevalence of HIV-1 drug resistance mutations (DRMs) among patients who failed first-line antiretroviral therapy (ART) and evaluates the genetic barrier of different regimens. The study cohort (n=271) included HIV-infected individuals who visited the Novosibirsk, Russia, HIV/AIDS clinic in 2018-2022. All patients received first-line ART prior to virological failure. Sociodemographic and HIV-related data were collected from medical records and self-reported questionnaires. HIV-1 pol gene sequences were generated, and the presence of HIV-1 DRM was assessed. The genetic barrier to resistance was assessed by combining treatment regimen and adherence data. Nonoptimal ART adherence was identified in 48.3% of patients and correlated with male sex, PWID, unemployment, and rural area residence. Most of the patients with high-level adherence were identified among those who were on TDF+3TC+DTG. HIV-1 DRMs were identified in 54.6% of the patients. The analysis of HIV-1 DRM, ART regimen, and adherence data classified TDF+3TC+DTG and TDF+3TC+LPV/r as treatment regimens with a high genetic barrier, whereas EFV-containing ART was classified as a regimen with a low genetic barrier. The current study delivers results on the efficacy of HIV-1 ART and treatment adherence in real-world practice settings. This report suggests that ART regimens with a high genetic barrier to resistance combined with improved treatment adherence may reduce the transmission of HIV-1 resistant variants.

Prevalence, Microbiological Profile, and Risk Factors of Surgical Site Infections in Saudi Patients with Colorectal Cancer.

Resection surgery in patients with colorectal cancer (CRC) patients is associated with potential complications, including surgical site infection (SSI). To estimate the prevalence rate of SSI, identify the common pathogens responsible for SSI, and determine potential risk factors for SSI development in a cohort from Saudi Arabia. Patients with CRC who underwent bowel resection surgery at King Abdulaziz Medical City, Riyadh, between January 01, 2016, and December 31, 2019, were retrospectively included. Demographics, comorbidities, surgical procedure data, and the results of preoperative laboratory tests were retrospectively collected from medical records through the health information system. The study population was divided into two groups: those who developed SSI and those who did not. A total of 92 patients with CRC who underwent resection surgery were included, of which 54 (58.7%) were males. The median age was 65 (IQR 55.5-75.0) years. SSI was observed in 25 (27.2%) patients. The most frequently isolated organisms were Escherichia coli and Pseudomonas aeruginosa, followed by Klebsiella pneumoniae, vancomycin-sensitive Enterococcus faecium, and methicillin-resistant Staphylococcus aureus. Three E. coli isolates were producers of extended-spectrum beta-lactamases, and two K. pneumoniae isolates exhibited a multidrug resistance profile. Low preoperative serum albumin level was identified as a significant independent risk factor for developing SSI (AOR = 0.853, 95% CI = 0.748-0.973, P = 0.0181). The study found a notable prevalence of SSI among the included patients. Gram-negative bacteria were more involved in SSI events and were also associated with drug-resistance patterns. Gut microbiota bacteria were most commonly involved in SSIs. Low preoperative serum albumin levels predicted the development of postoperative SSI, and thus its close monitoring and management before surgery could reduce the SSIs.

Microbiology and prognostic prediction model of bloodstream infection in patients with hematological malignancies.

In recent years, with the continuous development of treatments for hematological malignancies (HMs), the remission and survival rates of patients with HMs have been significantly improved. However, because of severe immunosuppression and long-term recurrent neutropenia during treatment, the incidence and mortality of bloodstream infection (BSI) were all high in patients with HMs. Therefore, we analyzed pathogens' distribution and drug-resistance patterns and developed a nomogram for predicting 30-day mortality in patients with BSIs among HMs. In this retrospective study, 362 patients with positive blood cultures in HMs were included from June 2015 to June 2020 at West China Hospital of Sichuan University. They were randomly divided into the training cohort (n = 253) and the validation cohort (n = 109) by 7:3. A nomogram for predicting 30-day mortality after BSIs in patients with HMs was established based on the results of univariate and multivariate logistic regression. C-index, calibration plots, and decision curve analysis were used to evaluate the nomogram. Among 362 patients with BSIs in HMs, the most common HM was acute myeloid leukemia (48.1%), and the most common pathogen of BSI was gram-negative bacteria (70.4%). The final nomogram included the septic shock, relapsed/refractory HM, albumin <30g/l, platelets <30×109/l before BSI, and inappropriate empiric antibiotic treatment. In the training and validation cohorts, the C-indexes (0.870 and 0.825) and the calibration plots indicated that the nomogram had a good performance. The decision curves in both cohorts showed that the nomogram model for predicting 30-day mortality after BSI was more beneficial than all patients with BSIs or none with BSIs. In our study, gram-negative bacterial BSIs were predominant in patients with HMs. We developed and validated a nomogram with good predictive ability to help clinicians evaluate the prognosis of patients.

Socio Clinical Profile of MDR TB Cases: A Study at DR –TB Center, SCB Medical College &amp; Hospital

Introduction India accounts for about one-fourth of the global burden of MDR-TB. This study aims to evaluate clinical profile and factors associated with tuberculosis drug resistance among patients from eastern India. Method All the MDR-TB cases registered under RNTCP PMDT services were included in the study between 1st April-2013 to 31st March 2014. This observational study was carried out by the Department of Pulmonary Medicine, SCB Medical College, Cuttack. Result Between April 2013 and March 2014, the IRL ATDC Center collected a total of 2205 sputum samples. Out of 2205, 245 (11%) had both INH and Rifampicin, 68 (3%), INH resistance, 359 (16.3%), and 51 (2.3%) had sputum contaminated with report awaiting. Mean age MDR TB was 35.6 (Standard deviation 13.769). The study shows 14.3% of the TB patients were illiterate. Out of 126 cases of MDR-TB presented with 140 co- morbidities at DR-TB Center. Discussion High rate of drug resistance pattern was found among the new sputum smear positive pulmonary tuberculosis patients and also high MDR tuberculosis. Risk factors such as age, sex, smoking, and alcoholism were independently associated with pulmonary MDR-TB. Our study concluded that young age, male sex, smear positivity, treatment failure, and the combination of smoking and alcoholism were identified as risk factors for Tuberculosis mortality.

Pre-Treatment HIV Drug Resistance and Genetic Diversity in Cameroon: Implications for First-Line Regimens.

The efficacy of first-line antiretroviral therapy (ART) may be hampered by the presence of HIV drug resistance (HIVDR). We described HIV-1 pre-treatment drug resistance (PDR) patterns, effect of viral clades on PDR, and programmatic implications on first-line regimens in Cameroon. A sentinel surveillance of PDR was conducted from 2014 to 2019. Sequencing of HIV-1 protease and reverse transcriptase was performed, and HIVDR was interpreted using Stanford HIVdb.v.9.4. In total, 379 sequences were obtained from participants (62% female, mean age 36 ± 10 years). The overall PDR rate was 15.0% [95% CI: 11.8-19.0] nationwide, with significant disparity between regions (p = 0.03). NNRTI PDR was highest (12.4%), of which 7.9% had DRMs to EFV/NVP. Two regions had EFV/NVP PDR above the 10% critical threshold, namely the Far North (15%) and East (10.9%). Eighteen viral strains were identified, predominated by CRF02_AG (65.4%), with no influence of genetic diversity PDR occurrence. TDF-3TC-DTG predictive efficacy was superior (98.4%) to TDF-3TC-EFV (92%), p < 0.0001. The overall high rate of PDR in Cameroon, not substantially affected by the wide HIV-1 genetic diversity, underscores the poor efficacy of EFV/NVP-based first-line ART nationwide, with major implications in two regions of the country. This supports the need for a rapid transition to NNRTI-sparing regimens, with TDF-3TC-DTG having optimal efficacy at the programmatic level.

Molecular Detection of Plasmid-Mediated Quinolone Resistance Genes (qnrA and aac(6′)-Ib-cr) in Drug Resistant Escherichia coli, Sudan

Background: The quinolone group, a synthetic antimicrobial, is widely used worldwide to treat many diseases, including those caused by Gram-negative bacteria. Escherichia coli and others are among the bacteria that produce quinolone resistance genes (qnr) such as qnrA and aac(6′)-Ib-cr. &#x0D; Objective: The present study aimed to the isolate Escherichia coli from patients attending some Hospitals in Wad Medani city, identification of drug resistance patterns and detection of the frequency of quinolones resistance genes; qnrA and aac(6′)-Ib-cr among isolated strains.&#x0D; Methods: A cross-sectional descriptive, hospital-based study included 119 Escherichia coli strains was conducted. A designed questionnaire used for demographic data collection and the attitude toward antimicrobials usage. Clinical specimens were processed for aerobic bacterial isolation and identification. Antimicrobial sensitivity performed by Kirby Bauer disc diffusion technique according to the CLSI guidelines. Presence of qnrA and aac(6′)-Ib-cr genes was assessed by multiplex PCR.&#x0D; Results: Most strains of Escherichia coli originated from urine 53.8% (64/119) and wounds 42.9% (51/119) specimens. Meropenem had the best effect against tested strains with susceptibility of 85% (101/119). Multiplex PCR assay, using specific primers, demonstrated that 41.2% (49/119) and 37.8% (45/119) of isolated Escherichia coli possessed qnrA and aac(6′)-Ib-cr genes respectively.&#x0D; Conclusion: The high rate of qnrA and aac (6)-Ib-cr genes among Escherichia coli necessitate the usage of molecular tools in detecting the genetic determinants of drug resistance microorganisms in countries such as Sudan.

Insight into Population Structure and Drug Resistance of Pediatric Tuberculosis Strains from China and Russia Gained through Whole-Genome Sequencing.

This study aimed to determine phenotypic and genotypic drug resistance patterns of Mycobacterium tuberculosis strains from children with tuberculosis (TB) in China and Russia, two high-burden countries for multi/extensively-drug resistant (MDR/XDR) TB. Whole-genome sequencing data of M. tuberculosis isolates from China (n = 137) and Russia (n = 60) were analyzed for phylogenetic markers and drug-resistance mutations, followed by comparison with phenotypic susceptibility data. The Beijing genotype was detected in 126 Chinese and 50 Russian isolates. The Euro-American lineage was detected in 10 Russian and 11 Chinese isolates. In the Russian collection, the Beijing genotype and Beijing B0/W148-cluster were dominated by MDR strains (68% and 94%, respectively). Ninety percent of B0/W148 strains were phenotypically pre-XDR. In the Chinese collection, neither of the Beijing sublineages was associated with MDR/pre-XDR status. MDR was mostly caused by low fitness cost mutations (rpoB S450L, katG S315T, rpsL K43R). Chinese rifampicin-resistant strains demonstrated a higher diversity of resistance mutations than Russian isolates (p = 0.003). The rifampicin and isoniazid resistance compensatory mutations were detected in some MDR strains, but they were not widespread. The molecular mechanisms of M. tuberculosis adaptation to anti-TB treatment are not unique to the pediatric strains, but they reflect the general situation with TB in Russia and China.

Concordance between Genotypic and Phenotypic Drug-Resistant Profiles of Shigella Isolates from Taiyuan City, Shanxi Province, China, 2005 to 2016.

Antimicrobial resistance in Shigella spp. is a global public health concern. In this study, the AMR phenotypic profiles of 10 kinds of antibiotics were compared with the genotypic profiles using genomic analysis of 218 Shigella isolates from Taiyuan City, Shanxi Province, China, 2005 to 2016. Core genome Multilocus Sequence Typing (cgMLST) based on the EnteroBase Escherichia/Shigella scheme was used to obtain the genetic relatedness of Shigella isolates. Multiple-drug resistance was observed in 96.79% Shigella spp., and the resistance to antimicrobial agents varied between S. flexneri and S. sonnei. The genotypic results correlated well with the phenotypic profiles with concordance rates of 96.42% and 94.50% in S. flexneri and S. sonnei isolates, respectively, from Taiyuan City, Shanxi Province. The sensitivity and specificity of the genotypic antimicrobial susceptibility testing (AST) were 97.56% and 95.34% for S. flexneri, and 95.65% and 93.31% for S. sonnei isolates, respectively. A discrepancy of genotypic and phenotypic AST results existed in some cephalosporin- and azithromycin-resistant Shigella isolates; there were no clear resistance patterns to predict ciprofloxacin resistance. There were major discrepancies between genotypic and phenotypic AST in the genotypically resistant but phenotypically susceptible isolates. The drug-resistance patterns and essential drug-resistance genes to predict the phenotypic drug-resistant profiles were the discrepancies between S. flexneri and S. sonnei isolates. Phylogenetic analysis showed that isolates of the same cluster but with different antibiotic-resistance gene patterns occurred because of the loss or gain of antibiotic-resistance genes located in the plasmids and multidrug-resistance islands. IMPORTANCE Antimicrobial resistance in Shigella spp. has become a global public health concern. In this study, we identified the antimicrobial susceptibility testing (AST) characteristics based on genomic sequences of 218 Shigella isolates and analyzed the correlation between genotypic and phenotypic antibiotic resistance profiles of Shigella spp., especially for fluoroquinolone, macrolides, and third-generation cephalosporins. Our results show that the genotypic results correlated with the phenotypic profiles with concordance rates of 96.42% and 94.50% in S. flexneri and S. sonnei isolates, respectively. The drug-resistance patterns and essential drug-resistance genes to predict the phenotypic drug-resistant profiles of S. flexneri and S. sonnei isolates in Taiyuan city were distinct. The discrepancy between genotypic and phenotypic AST was considerable in the genotypically resistant but phenotypically susceptible isolates. The information on drug resistance and resistance genes in this study can offer more details on the prevalence of drug resistance of Shigella spp.

Prevalence of MLSB Phenotypes of &lt;i&gt;Staphylococcus aureus&lt;/i&gt; isolates in a tertiary care hospital of Delhi

Against the backdrop of the ever-changing Staphylococcal resistance pattern, clindamycin remains a viable therapeutic alternative Variation of Clindamycin drug resistance patterns with geographic area make inducible clindamycin resistance testing imperative for all staphylococcal isolates to avoid therapeutic failure. This was a prospective study conducted over a period of 1.5 years from January 2021 until June 2022. Prevalence of different MLSB Phenotypes of Staphylococcus aureus isolates was determined by standard disc diffusion method as per CLSI guidelines. Pyogenic samples received in the Microbiology lab that yielded Staphylococcus aureus were further tested for the presence of clindamycin resistance by disc diffusion method. Out of 6586 total pyogenic and respiratory specimens received in the lab, Staphylococcus aureus was yielded in 752 samples. On further testing for the MLSB phenotypes, 16.3% isolates were found to be iMLSB, 19.28% were cMLSB, 43.1% were of MSB type. ICR screening will reduce the unessential subjection of the patient to the antibiotic, and would prevent unnecessary adverse effects in the patients.

Whole-Genome Sequence-Based Characterization of Pre-XDR M. tuberculosis Clinical Isolates Collected in Kazakhstan.

Kazakhstan has a high burden of multidrug-resistant tuberculosis in the Central Asian region. This study aimed to perform genomic characterization of Mycobacterium tuberculosis strains obtained from Kazakhstani patients with pre-extensively drug-resistant tuberculosis diagnosed in Kazakhstan. Whole-genome sequencing was performed on 10 pre-extensively drug-resistant M. tuberculosis strains from different regions of Kazakhstan. All strains had high-confidence resistance mutations according to the resistance grading system previously established by the World Health Organization. The genome analysis was performed using TB-Profiler, Mykrobe, CASTB, and ResFinder. Valuable information for understanding the genetic diversity of tuberculosis in Kazakhstan can also be obtained from whole-genome sequencing. The results from the Phenotypic Drug Susceptibility Testing (DST) of bacterial strains were found to be consistent with the drug resistance information obtained from genomic data that characterized all isolates as pre-XDR. This information can help in developing targeted prevention and control strategies based on the local epidemiology of tuberculosis. Furthermore, the data obtained from whole-genome sequencing can help in tracing the transmission pathways of tuberculosis and facilitating early detection of outbreaks. The results from whole-genome sequencing of tuberculosis clinical samples in Kazakhstan provide important insights into the drug resistance patterns and genetic diversity of tuberculosis in the country. These results can contribute to the improvement of tuberculosis control and management programs in Kazakhstan.

A novel strategy to characterize the pattern of β-lactam antibiotic-induced drug resistance in Acinetobacter baumannii

Carbapenem-resistant Acinetobacter baumannii (CRAb) is an urgent public health threat, according to the CDC. This pathogen has few treatment options and causes severe nosocomial infections with > 50% fatality rate. Although previous studies have examined the proteome of CRAb, there have been no focused analyses of dynamic changes to β-lactamase expression that may occur due to drug exposure. Here, we present our initial proteomic study of variation in β-lactamase expression that occurs in CRAb with different β-lactam antibiotics. Briefly, drug resistance to Ab (ATCC 19606) was induced by the administration of various classes of β-lactam antibiotics, and the cell-free supernatant was isolated, concentrated, separated by SDS-PAGE, digested with trypsin, and identified by label-free LC–MS-based quantitative proteomics. Thirteen proteins were identified and evaluated using a 1789 sequence database of Ab β-lactamases from UniProt, the majority of which were Class C β-lactamases (≥ 80%). Importantly, different antibiotics, even those of the same class (e.g. penicillin and amoxicillin), induced non-equivalent responses comprising various isoforms of Class C and D serine-β-lactamases, resulting in unique resistomes. These results open the door to a new approach of analyzing and studying the problem of multi-drug resistance in bacteria that rely strongly on β-lactamase expression.