Extended-spectrum β-lactamase-producing Escherichia coli (ESBL-E) are becoming increasingly widespread in Vietnam. Antibiotics are detected in many Vietnamese foods; however, the effect of ESBL-E and ...antibiotic consumption on intestinal bacteria has not been studied sufficiently. Here, we investigated the effect of oral administration of ESBL-E (TB19) and cefotaxime on luminescence-emitting cefotaxime-sensitive E. coli (X14). Mice were given water containing TB19 and then received three injections of 1.0 × 108 CFU of X14 harboring a luciferase gene. The mice were administered 100 μg of cefotaxime and luminescent bacteria were monitored over 24 h, following which luminescent bacteria were isolated from mouse feces. Luminescence continued to be detected in mice administered TB19 24 h after cefotaxime ingestion. Fecal analysis revealed two types of luminescent colonies: cefoxitin-resistant E. coli (X14-R) and Pseudomonas aeruginosa. Pulse-field gel electrophoresis confirmed that X14-R was a clonal strain of X14, suggesting that X14 survived using ESBLs originating from TB19 and acquired cefoxitin resistance due to cefotaxime consumption. Moreover, in vitro analysis of X14 indicated that expression of the ampC gene was upregulated by cefotaxime. Overall, ESBL-E and cefotaxime promoted the expansion of cefoxitin-resistant E. coli in the absence of plasmid-mediated gene transfer.
The spread of plasmid-mediated quinolone resistance determinants (qnr-like determinants, aac(6′)-Ib-cr and qepA genes) was evaluated in a collection of 281 nalidixic acid-resistant enterobacterial ...isolates recovered between September 2005 and December 2007 at the Sahloul Hospital, Sousse, Tunisia. Sixteen percent of those isolates carried qnr genes encoding the QnrB1, QnrB2, QnrA6 or QnrS1 determinants. Most qnr-positive isolates were extended-spectrum ß-lactamase (ESBL) producers, being predominantly of the CTX-M-15 type, but also of the SHV-28 and SHV-12 types. The qnr genes were located on plasmids with a size in the range 55–150 kb. The qnrB2 gene was associated with sul1-type integron structures and the qnrB1 gene was associated with orf1005, whereas the genetic environment of qnrA6 was unknown. In two isolates, the qnrS1 gene was located downstream of an ISEcl2 element on plasmids that often carried the narrow-spectrum ß-lactamase gene blaLAP-2; qepA and aac(6′)-Ib-cr were not detected. The present study highlights the wide spread of Qnr-like determinants in Tunisia, with an association with the ESBL CTX-M-15 in human clinical isolates.
The rapid detection of resistance is a challenge for clinical microbiologists who wish to prevent deleterious individual and collective consequences such as (i) delaying efficient antibiotic therapy, ...which worsens the survival rate of the most severely ill patients, or (ii) delaying the isolation of the carriers of multidrug-resistant bacteria and promoting outbreaks; this last consequence is of special concern, and there are an increasing number of approaches and market-based solutions in response. Areas covered: From simple, cheap biochemical tests to whole-genome sequencing, clinical microbiologists must select the most adequate phenotypic and genotypic tools to promptly detect and confirm β-lactam resistance from cultivated bacteria or from clinical specimens. Here, the authors review the published literature from the last 5 years about the primary technical approaches and commercial laboratory reagents for these purposes, including molecular, biochemical and immune assays. Furthermore, the authors discuss their intrinsic and relative performance, and we challenge their putative clinical impact. Expert commentary: Until the availability of fully automated wet and dry whole genome sequencing solutions, microbiologists should focus on inexpensive biochemical tests for cultured isolates or monomicrobial clinical specimen and on using the expensive molecular PCR-based strategies for the targeted screening of complex biological environments.
Rapid evaluation of antimicrobial susceptibility is important in the treatment of nosocomial infections by Gram-negative bacteria, which increasingly carry carbapenemases and metallo-β-lactamases. We ...developed loop-mediated isothermal amplification (LAMP)-based assays for four β-lactamase genes (
,
,
group, and
). The assays were evaluated using eight reference bacterial strains (
,
,
, and
) harboring six β-lactamase genes. A total of 55 Gram-negative bacterial strains, including 47 clinical
isolates, fully characterized by next-generation sequencing (NGS), were used to evaluate the LAMP assays. The results were compared to those of conventional PCR. The LAMP assays were able to detect as few as 10 to 100 copies of a gene, compared to 10 to 10
copies for conventional PCR. The LAMP assay detected four β-lactamase genes with a sensitivity similar to that using purified DNA as the template in DNA-spiked urine, sputum, and blood specimens. By contrast, the sensitivity of PCR was 1- to 100-fold lower with DNA-spiked clinical specimens. Therefore, the LAMP assays were proved to be an appropriate tool for the detection of four β-lactamases.
The present study was conducted to determine prevalence, virulence gene profile, serotyping, and antibiotic resistance patterns of Salmonella in birds kept under the backyard system in West Bengal, ...India. The study also incorporated the detection of Salmonella prevalence in their environment, including feed, drinking water, utensils, litter, dried manure under the house, soil, and eggs, which helped to formulate a biosecurity strategy. The study was conducted in 4 agro-climatic zones, such as the terai, new alluvial, red laterite, and coastal. Out of 360 samples, 22 Salmonella isolates (6.1%) were identified. Salmonella were isolated from cloacal swabs of 6 birds (15%, n = 40), from 4 feed samples (10%, n = 40), 8 drinking water samples (20%, n = 40), and 4 eggs (10%, n = 40). Similar antigenic structure, nucleotide sequence (invA) of Salmonella Enteritidis and Typhimurium, and randomly amplified polymorphic DNA banding patterns of Salmonella Enteritidis were observed. It seems that the same Salmonella isolate was present in feed sample, cloacal swabs, and eggs in the terai zone, whereas, it was found in drinking water, birds, and eggs in the new alluvial and in drinking water and birds in the coastal zone. A zone-specific biosecurity strategy was formulated based on the findings. The isolates were found to be resistant to chloramphenicol, ciprofloxacin, gentamicin, levofloxacin, norfloxacin, and oxytetracycline. None of the isolates possessed genes for major extended spectrum β-lactamases. Thus, the present study identified the source of Salmonella contamination in the backyard chickens and their eggs in India with possible forms of biosecurity strategies. Our study was the first attempt in India to determine the prevalence, virulence gene profile, serotyping, and antibiotic resistance pattern of Salmonella in backyard birds, including the environment and product.
•-Some community-onset pneumonias are caused by drug resistant pathogens.•-There is no consensual rule to identify patients who need wider spectrum antibiotics.•-In a prospective cohort study, we aim ...to identify risk factors for resistant agents.•-Previous antibiotic use and being bed-ridden were independent risk factors.•-Our multivariable model has a discriminative power of 0.832, 95%CI 0.756–0.908.
: There is no consensual definition of risk factors for drug resistant pathogens (DRP) in community-onset pneumonia (COP). Healthcare-associated pneumonia criteria have been abandoned because they were found to have weak discriminative power. Our aim was to identify risk factors for DRP in COP.
: Prospective cohort study, conducted over a two years’ period, in a community-based hospital, including all adult patients with COP criteria. Univariate and multivariate logistic regression modeling were performed to understand the association of risk factors (demographic, clinical and epidemiological) with COP by a DRP (PES: Pseudomonas aeruginosa, extended-spectrum ß-lactamase producing Enterobacteriaceae, Methicillin-resistant Staphylococcus aureus; and other non-fermenting gram-negative bacteria, namely Acinetobacter baumannii).
: A total of 660 cases of COP were included, with a mean (±SD) age of 74±15 years and 58.9% of males. Microbiological documentation was possible in 32.6% of the cases. There were 197 cases selected for further analysis, of which 37 were cases of PES. The multivariate logistic regression model retained antibiotic use in the previous 90 days (adjusted OR=4.411, 95%CI 1.745-11.148) and being bed-ridden (adjusted OR=5.492, 95%CI 2.121-14.222), adjusted for Charlson's Index, CURB 65 and provenience from a long-term care facility. The area under the ROC curve for this model was 0.832, 95%CI 0.756-0.908, higher than the application of the HCAP criteria (AUROC = 0.676, 95%CI 0.582-0.770).
: In this study, antibiotic use in the previous 90 days and being bed-ridden were independently associated with COP caused by DRP, after adjustment for Charlson's Index, CURB 65 and provenience from a long-term care facility.
Klebsiella pneumoniae resistant to almost all ß-lactams except imipenem designated as ISMRK (imipenem-susceptible meropenem-resistant Klebsiella) is emerging in Japan. All ISMRK carries
bla
IMP-6 ...which differs from
bla
IMP-1 by only a single nucleotide at position 640. We devised a rapid detection system of
bla
IMP-6 by using ARMS PCR.
Antimicrobial resistance (AMR) is a global concern among infectious diseases. Bloodstream infections can potentially become life-threatening if they become untreatable with conventional ...antimicrobials. This review aims to provide an understanding of the AMR prevalence and trends of common bacteremic pathogens, namely Escherichia coli and Staphylococcus aureus in the World Health Organization (WHO) Africa region.
PubMed and Google Scholar were searched using relevant keywords for published human studies (excluding case reports and reviews) reporting bacteremic AMR data on the pathogens of interest between 2008 and 2019. Two reviewers independently screened the articles against a pre-defined eligibility criterion. Data extraction and analysis were achieved with different platforms: Covidence, Excel, R version 3.6.3, and QGIS v3.4.5. The pooled prevalence, 95% confidence intervals, and I2 index (a measure of heterogeneity) were calculated for the various pathogen-antibiotic combinations.
Five hundred sixty-two papers were retrieved, with 27 papers included in the final analysis. Only 23.4% (11/47) of member states of the WHO African region had reports on AMR in bacteremia. The Clinical and Laboratory Standards Institute (CLSI) (78.5%) was the most common standard used in the region. For E. coli, the pooled resistance was: cefotaxime (42%), imipenem (4%), meropenem (0%), and colistin (0%). For S. aureus, the calculated pooled resistance was cloxacillin (34%), oxacillin (12%), and vancomycin (0%). There was a high degree of variation across studies (I2 > 90%).
The pooled resistance rates indicate a concerning degree of methicillin-resistant and Extended Spectrum-ß-lactamase–producing pathogens. The paucity of AMR data also presents challenges for a comprehensive understanding of the situation in the region. Continent-wide and standardized surveillance efforts therefore need strengthening.
•ESBL-positive bacteremia were associated with CVC, hospital exposure, and exposure to antimicrobial therapy within the previous 6 months.•Neutropenic patients with ESBL bacteremia have increased ...morality due to other factors than ESBL status.•Mortality was associated with high Pitt bacteremia score but not inappropriate empirical therapy.
Patients with neutropenia are vulnerable to serious infections. During the last decade, increased prevalence of extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae has affected immunocompromised patients. We conducted a single-center case–control study to evaluate factors associated with ESBL-positive bacteremia among neutropenic patients, and its clinical impact. The study included adult patients with hematologic or oncologic diseases diagnosed with ESBL-positive and ESBL-negative Escherichia coli or Klebsiella pneumoniae bacteremia during febrile neutropenia between January 2010 and October 2017 at the Shaare Zedek Medical Center, Jerusalem, Israel. Analyses included risk factors for ESBL-positive bacteremia, appropriateness of empiric antibiotics, mortality, length of stay, and intensive care unit (ICU) admission. Univariate and multivariate models were constructed. The cohort (80 patients), consisted of 54 ESBL-negative and 26 ESBL-positive Gram-negative bacteremia. Multivariate analysis suggested ESBL-positive bacteremia to be associated with long-term central venous catheter (CVC) (odds ratio (OR), 8.7; 95% confidence interval (CI), 1.6–48.1; P=0.01, index culture obtained 48 h post-admission (OR, 3.6; 95% CI, 1–12.3; P=0.04), and exposure to previous antimicrobial therapy (OR, 12.6; 95% CI, 2.1–74; P<0.01). There were no significant differences between groups with regard to length of stay, ICU admission, or mortality rates. Mortality was associated with high Pitt bacteremia score but not inappropriate empirical therapy. Previous antimicrobial therapy, long-term CVC, and hospital-acquired bacteremia were associated with ESBL bacteremia. Neutropenic patients with ESBL bacteremia have increased morality due to other factors than ESBL status. These findings should be validated in other centers and with larger populations.
Through investigating antimicrobial susceptibility patterns of Enterobacteriaceae in community-acquired urinary tract infection (CA-UTI), we provide basic evidence for the use of empirical ...antibiotics in CA-UTI.
We retrospectively reviewed the medical records of patients over the age of 19 years who visited a hospital in Seoul between January 2012 and December 2016 for a CA-UTI. Urine cultures were used to identify causative organisms. We investigated extended-spectrum β-lactamase (ESBL) production and the antimicrobial susceptibility of Enterobactereiaceae. We evaluated recommended empirical antibiotics numerically by calculating the syndrome-specific likelihood of inadequate therapy (LIT) for the last 2 years (interpretation of the LIT A value: 1 out of A people is likely to receive inadequate empirical antibiotics).
Urine cultures were performed in 1,605 out of 2,208 patients who were diagnosed with CA-UTI, and causative pathogens were identified in 1,134 (70.7%) cases. There were 998 (88.0%) cases of Enterobacteriaceae and Escherichia coli was the most common pathogen, accounting for 80.3% of cases (911 cases). The overall resistance rates to trimethoprim-sulfamethoxazole, fluoroquinolones, and cefotaxime were 31.7%, 23.2%, and 13.5%, respectively. There were 128 (10.8%) cases of ESBL-producing Entererobacteriaceae with an increasing but non-significant trend (P = 0.255). The LIT for CA-UTI in the past two years was highest for ertapenem and imipenem. Fluoroquinolones ranked 11th, with a LIT of 8.2, and cefotaxime ranked higher, at 10.5. In ESBL-producing Enterobacteriaceae, except for carbapenems, amikacin and piperacillin-tazobactam showed the highest susceptibility rates at 99.2% and 94.3%, respectively.
Empiric treatment with fluoroquinolones in CA-UTI should be carefully considered, given the high resistance rate. The proportion of ESBL-producing Entererobacteriaceae in CA-UTI has increased to a high level in Korea. Amikacin and piperacillin-tazobactam could be considered for empiric treatment in patients at risk for ESBL-producing Entererobacteriaceae when considering alternatives to carbapenems.
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