Introduction: Bacterial skin and soft tissue infections (SSTIs) are a cause of frequent inpatient and outpatient care visits whose causative agents are associated with a high antimicrobial resistance burden. For insig...Introduction: Bacterial skin and soft tissue infections (SSTIs) are a cause of frequent inpatient and outpatient care visits whose causative agents are associated with a high antimicrobial resistance burden. For insights on antimicrobial susceptibilities in a rural setting, we examined specimens from suspected SSTIs from two public health facilities in Kenya. We additionally assessed antibiotic use, appropriateness of empiric therapy and risk factors for SSTI. Methodology: Between 2021 and 2023, 265 patients at Kisii and Nyamira County Referral hospitals were enrolled. Wound swabs/aspirates were collected and processed following standard microbiological procedures. Identification and antimicrobial susceptibility were performed using the VITEK 2 Compact platform. Demographic, clinical, and microbiological data were analyzed with R Statistical software. Results: S. aureus was isolated in 16.2% (43/265) of patients with a methicillin resistance (MRSA) proportion of 14% (6/43). While 13/15 drugs elicited susceptibilities ranging from 84% - 100%, penicillin (16%) and trimethoprim-sulfamethoxazole [TMP-SXT] (23%) yielded the lowest susceptibilities. Escherichia coli (n = 33), Klebsiella pneumoniae (n = 8), Pseudomonas aeruginosa (n = 8), and Citrobacter species (n = 4) were the most commonly isolated gram-negative species. Gram-negative strains showed high susceptibilities to most of the tested drugs (71% - 100%) with the exception of ampicillin (18%), TMP-SXT (33%), and first and second generation cephalosporins. Conclusions: The low MRSA prevalence and generally high antibiotic susceptibilities for S. aureus and gram-negative bacteria present opportunities for antibiotic stewardship in the study setting. Diminished susceptibilities against penicillin/ampicillin and TMP-SXT accord with prevailing local data and add a layer of evidence for their cautious empiric use.展开更多
Background The prevalence of hospital-acquired infections caused by carbapenem-resistant gram-negative bacteria(CRGNB)is increasing worldwide.Several risk factors have been associated with such infections.The present ...Background The prevalence of hospital-acquired infections caused by carbapenem-resistant gram-negative bacteria(CRGNB)is increasing worldwide.Several risk factors have been associated with such infections.The present study aimed to identify risk factors and determine the mortality rates associated with CRGNB infections in intensive care units.Methods This retrospective case-control study was conducted at Erciyes University Hospital(Kayseri,Turkey)between January 2017 and December 2021.Demographic and laboratory data were obtained from the Infection Control Committee data and record system.Patients who had CRGNB infection 48–72 h after hospitalization were assigned to the case group,while those who were not infected with CRGNB during hospitalization formed the control group.Risk factors,comorbidity,demographic data,and mortality rates were compared between the two groups.Results Approximately 1449 patients(8.97%)were monitored during the active follow-up period;of those,1171 patients were included in this analysis.CRGNB infection developed in 14 patients(70.00%)who had CRGNB colonization at admission;in 162(78.26%)were colonized during hospitalization,whereas 515(54.56%)were not colonized.There was no significant difference in age,sex(male/female)or comorbidities.The total length of hospital stay was statistically significantly longer(P=0.001)in the case group(median:24[interquartile range:3–378]days)than the control group(median:16[interquartile range:3–135]days).The rates of colonization at admission(25.5%;vs.10.6%,P=0.001)and mortality(64.4%vs.45.8%,P=0.001)were also significantly higher in the cases than in the control group,respectively.In the univariate analysis,prolonged hospitalization,the time from intensive care unit admission to the development of infection,presence of CRGNB colonization at admission,transfer from other hospitals,previous antibiotic use,enteral nutrition,transfusion,hemodialysis,mechanical ventilation,tracheostomy,reintubation,central venous catheter,arterial catheterization,chest tube,total parenteral nutrition,nasogastric tube use,and bronchoscopy procedures were significantly associated with CRGNB infections(P<0.05).Multivariate analysis identified the total length of stay in the hospital(odds ratio[OR]=1.02;95%confidence interval[CI]:1.01 to 1.03;P=0.001),colonization(OR=2.19;95%CI:1.53 to 3.13;P=0.001),previous antibiotic use(OR=2.36;95%CI:1.53 to 3.62;P=0.001),intubation(OR=1.59;95%CI:1.14 to 2.20;P=0.006),tracheostomy(OR=1.42;95%CI:1.01 to 1.99;P=0.047),and central venous catheter use(OR=1.62;95%CI:1.20 to 2.19;P=0.002)as the most important risk factors for CRGNB infection.Conclusions Colonization,previous use of antibiotics,and invasive interventions were recognized as the most important risk factors for infections.Future research should focus on measures for the control of these parameters.展开更多
PCR and DNA sequencing were used to screen and characterize integrons and resistance genes in Gram-negative bacteria isolated from seafood products in Japan.A total of 215 Gram-negative bacteria were isolated from loc...PCR and DNA sequencing were used to screen and characterize integrons and resistance genes in Gram-negative bacteria isolated from seafood products in Japan.A total of 215 Gram-negative bacteria were isolated from local and imported seafood samples collected from retail markets in Hiroshima Prefecture.Class 1 integrons containing gene cassettes encoding resistance to trimethoprim展开更多
Humanity is facing an enormous and growing worldwide threat from the emergence of multi-drug-resistant(MDR)Gram-negative bacteria such as Escherichia coli,Klebsiella pneumoniae,and Acinetobacter baumannii.Polymyxin B ...Humanity is facing an enormous and growing worldwide threat from the emergence of multi-drug-resistant(MDR)Gram-negative bacteria such as Escherichia coli,Klebsiella pneumoniae,and Acinetobacter baumannii.Polymyxin B and E(colistin)constitute the last-line therapies for treating MDR Gram-negative bacteria.Polymyxin is a cationic antibacterial peptide that can destroy the outer membrane of Gram-negative bacteria.With the increasing clinical application of polymyxin,however,there have been many reports of the occurrence of polymyxin-resistant Gram-negative bacteria.This resistance is mainly mediated by the modification or complete loss of lipopolysaccharide(LPS).LPS is also a virulence factor of Gram-negative bacteria,and alterations of LPS may correlate with virulence.Although it is generally believed that the biological costs associated with drug resistance may enable benign susceptible bacteria to overcome resistant bacteria when antibiotic pressure is reduced,some studies have shown that polymyxin-resistant bacteria are associated with higher virulence and greater fitness compared with their susceptible counterparts.To predict the development of polymyxin resis-tance and evaluate interventions for its mitigation,it is important to understand the relative biological cost of polymyxin resistance compared with susceptibility.The impact of polymyxin resistance mecha-nisms on the virulence and fitness of these three Gram-negative bacteria are summarized in this review.展开更多
Antibiotic resistant bacteria pathogens remain the leading cause of shellfish borne diseases and a major health threat to humans worldwide. The objectives of this study were to isolate, identify, and determine the ant...Antibiotic resistant bacteria pathogens remain the leading cause of shellfish borne diseases and a major health threat to humans worldwide. The objectives of this study were to isolate, identify, and determine the antibiotic resistance patterns of Gram-negative bacteria from shellfish. We analyzed a total of 540 shellfish (117 clams, 88 oysters, and 136 periwinkles) samples collected from different vendors at Iko and Douglas Creeks in Akwa Ibom State, South-South Nigeria. Conventional cultural techniques, morphological, biochemical characteristics, and PCR amplification were used to identify the bacterial isolates. Antibiotic susceptibility tests (Kirby-Bauer disk diffusion method) and ESBL phenotype (disk) of the isolates were performed. One hundred and thirty-five (135) Gram-negative bacteria comprising 5 genera and 14 species were detected at a prevalence of: <i>Alcaligenes faecalis</i> <i><b>TRB</b></i>-7 38 (28.2%), <i>Pseudomonas oryzihabitans strain <b>KCB</i>005</b> 16 (11.9%), <i>Paenalcaligenes retgerii strain <b>B</i>5</b> 12 (8.9%) <i>Pseudomonas aeruginosa <b>JB</i>2</b> 10 (7.4%), <i>Providencia stuartii <b>DMC</i>-28b</b> 9 (6.7%), <i>Alcaligenes species <b>TLT</i>151</b> 8 (5.9%), <i>Pseudomonas aeruginosa <b>CIFRI DTSB</i>1</b> 7 (5.2%), <i>Paenalcaligenes species <b>UN</i>24</b> 7 (5.2%), <i>Alcaligenes faecalis <b>BT</i>10</b> 7 (5.2%), <i>Vibrio species strain <b>PrVy</i>108</b> 6 (4.4%), <i>Pseudomonas xiamenensis <b>C</i>10-2</b> 5 (3.7%), <i>Providencia vemicola <b>Bu</i>15_38</b> 4 (2.9%), <i>Pseudomonas anguillisceptica</i> <b>4029</b> 3 (2.2%), and <i>Pseudomonas aeruginosa <b>N</i>15-01092</b> 3 (2.2%). All tested isolates showed various degrees of resistance to the thirteen antimicrobials evaluated. High levels of resistance (100%) to cefepime and imipenem were expressed by all isolates except the <i>Providencia</i> species. For the EBSL indicators, all isolates apart from <i>Alcaligenes</i> species were resistant (100%) to ceftriaxone. All <i>Vibrio</i> species were susceptible to norfloxacin, nalidixic acid, and ceftazidime. The identification of antibiotic resistant Gram-negative bacteria (GNARB) from shellfish in this study highlights the risk of disseminated multi-drug resistance—a serious public health concern.展开更多
Tigecycline serves as a critical“final-resort”antibiotic for treating bacterial infections caused by multidrug-resistant bacteria for which treatment options are severely limited.The increasing prevalence of tigecyc...Tigecycline serves as a critical“final-resort”antibiotic for treating bacterial infections caused by multidrug-resistant bacteria for which treatment options are severely limited.The increasing prevalence of tigecycline resistance,particularly among Gram-negative bacteria,is a major concern.Various mechanisms have been iden-tified as contributors to tigecycline resistance,including upregulation of nonspecific Resistance Nodulation Divi-sion(RND)efflux pumps due to mutations in transcriptional regulators,enzymatic modification of tigecycline by monooxygenase enzymes,and mutations affecting tigecycline binding sites.This review aims to consolidate our understanding of tigecycline resistance mechanisms in Gram-negative bacteria and offer insights and perspectives for further drug development.展开更多
Over the past years, infectious disease has caused enormous economic loss in pig industry. Among the pathogens, gram negative bacteria not only cause inflammation, but also cause different diseases and make the pigs m...Over the past years, infectious disease has caused enormous economic loss in pig industry. Among the pathogens, gram negative bacteria not only cause inflammation, but also cause different diseases and make the pigs more susceptible to virus infection. Vaccination, medication and elimination of sick pigs are major strategies of controlling disease. Genetic methods, such as selection of disease resistance in the pig, have not been widely used. Recently, the completion of the porcine whole genome sequencing has provided powerful tools to identify the genome regions that harboring genes controlling disease or immunity. Immunogenornics, which combines DNA variations, transcriptorne, immune response, and QTL mapping data to illustrate the interactions between pathogen and host immune system, will be an effective genomics tool for identification of disease resistance genes in pigs. These genes will be potential targets for disease resistance in breeding programs. This paper reviewed the progress of disease resistance study in the pig focusing on Gram-negative bacilli. Major porcine Gram-negative bacilli and diseases, suggested candidate genes/pathways against porcine Gram-negative bacilli, and distributions of QTLs for immune capacity on pig chromosomes were summarized. Some tools for immunogenomics research were described. We conclude that integration of sequencing, whole genome associations, functional genomics studies, and immune response information is necessary to illustrate molecular mechanisms and key genes in disease resistance.展开更多
<b>Introduction:</b> Oral cancer is the third most prominent type of cancer in Bangladesh. During or after oral cancer treatment, immune-compromised cancer patients may be susceptible to an infection by mu...<b>Introduction:</b> Oral cancer is the third most prominent type of cancer in Bangladesh. During or after oral cancer treatment, immune-compromised cancer patients may be susceptible to an infection by multi-drug-resistant opportunistic microbes. This study aims to identify the prevalent microorganisms from the infected site of oral cancer patients and observe their antibiotic susceptibility pattern. <b>Materials and Methods:</b> Clinical samples were collected from the infected sites of oral cancer patients and healthy people. The swabs collected were placed on nutrient agar slant, then incubated for 24 hours at 37ºC. Bacteria from the slant were inoculated in several selective media (Mannitol Salt Agar Media, KF Streptococcus Agar media, Cetrimide Agar, Eosin Methylene Blue Agar). Several biochemical tests identified opportunistic microorganisms. Finally, the antibiotic susceptibility test was performed by the Kirby Bauer disc diffusion method. <b>Results:</b> The study found that 65.4% of microbes isolated from the patients’ oral cavities were Gram-negative bacteria, and 34.6% were Gram-positive bacteria. Among the patient group isolates (n = 55), the most prevalent organism was <i>Pseudomonas</i> spp. (30;54.54%). Others were <i>Klebsiella</i> spp. (27;49.09%), <i>Staphylococcus</i> spp. (24;43.63%), <i>E. coli</i> (14;25.45%), <i>Streptococcus</i> spp. (14;25.45%), <i>Proteus</i> spp. (12;21.8%) and <i>Enterococcus</i> spp. (6;10.90%). Both Gram-positive and Gram-negative microbes from the patient group have shown high resistance to the commonly used antibiotics. In the control group (n = 50), the most prevalent organism was <i>Staphylococcus</i> spp. (15;30%). Other organisms were <i>Streptococcus</i> spp. (6;12%), <i>Klebsiella</i> spp. (11;22%), <i>E. coli</i> (3;6%), <i>Streptococcus</i> spp. (14;25.45%), <i>Pseudomonas</i> spp. (8;16%). The microbes of the control group showed less resistance to the antibiotics and rather showed sensitivity to them. <b>Conclusion:</b> The study revealed a high prevalence of multi-drug-resistant opportunistic microbes on immune-compromised oral cancer patients compared to microbes isolated from healthy people’s oral cavity.展开更多
The study is to identify trends and levels of antibiotic resistance of some common Gram-negative strains over time. The samples were collected from Vietnam Military Hospital 103 between 2014 and 2019. A total of 405 &...The study is to identify trends and levels of antibiotic resistance of some common Gram-negative strains over time. The samples were collected from Vietnam Military Hospital 103 between 2014 and 2019. A total of 405 <i>Acinetobacter baumannii</i>., 528 <i>Pseudomonas aeruginosa</i>, 741 <i>Escherichia coli</i>, and 352 <i>Klebsiella pneumoniae</i> strains were identified and antimicrobial susceptibility was by Vitek system and Etest method. The multi-drug resistance (MDR) was major proportion of four common bacteria. In particular, there is a tendency to shift from MDR to Extended drug resistance (XDR) or possibly Pan drug resistant (pPDR). <i>A. baumannii</i> had the highest level of antibiotic resistance, namely, carbapenem (61.5% - 82.5%) and cephalosporin (72.7% - 88.7%). <i>P. aeruginosa</i> resisted most of commonly antibiotics, ranging from 50% to 70%. <i>E. coli</i> had a high resistance with antibiotics like ampicillin (87.2% - 97.6%) and the 3rd generation cephalosporins (up to 79.6%). <i>K. pneumoniae</i> resisted carbapenem from 14.7% to 44.4%, and other antibiotics with the higher rate of 40%. The collected data will be a prerequisite for further studies on mechanisms and factors related to antibiotic resistant bacteria, in order to find out a rational and effective using strategy of antibiotics.展开更多
Background: Aerosolized amikacin (AA) is a current option for the management of ventilator-associated pneumonia (VAP) caused by multidrug-resistant Gram-negative bacteria (MDR-GNB), as it is reported that AA co...Background: Aerosolized amikacin (AA) is a current option for the management of ventilator-associated pneumonia (VAP) caused by multidrug-resistant Gram-negative bacteria (MDR-GNB), as it is reported that AA could increase the alveolar level of the drug without increasing systemic toxicity. This study aimed to evaluate the efficacy and safety of AA as an adjunctive therapy for VAP caused by MDR-GNB. Methods: In this single-center, double-blind study conducted in a 36-bed general Intensive Care Unit (ICU) in a tertiary hospital from June 2014 to June 2016, 52 ICU patients with confirmed MDR-GNB VAP were randomized to two groups (AA group, n - 27 and placebo group, n = 25). Amikacin (400 rag, q8h) or saline placebo (4 ml, q8h) was aerosolized for 7 days. The attending physician determined the administration of systemic antibiotics for VAP. Patients were tbllowed up for 28 days. Bacteriological eradication, clinical pulmonary infection score (CP1S), and serum creatinine were assessed on day 7 of therapy. New resistance to amikacin, cure rate of VAP, weaning rate, and mortality were assessed on day 28. Results: The baseline characteristics of patients in both groups were similar. At the end of the treatment, 13 of the 32 initially detected bacterial isolates were eradicated in AA group, compared to 4 of 28 in placebo group (41% vs. 14%, P - 0.024). As for patients, 11 of 27 patients treated with AA and 4 of 25 patients treated with placebo have eradication (41% vs. 16%, P = 0.049). The adjunction of AA reduced CPIS (4.2 ± 1.6 vs. 5.8 ± 2.1, P = 0.007). New drug resistance to amikacin and the change in serum creatinine were not detected in AA group. No significant differences in the clinical cure rate in survivors (48% vs. 35%, P = 0.444), weaning rate (48% vs. 32%, P = 0.236), and mortality (22% vs. 32%, P = 0.427) were detected between the two groups on day 28. Conclusions: As an adjunctive therapy of MDR-GNB VAP, AA successfully eradicated existing MDR organisms without inducing new resistance to amikacin or change in serum creatinine. However, the improvement of mortality was not found.展开更多
Objective: To evaluate the in vitro antibacterial properties and the ability to potentiate some common antibiotics effects of the methanol extracts of 11 Cameroonian food plants on 29 Gram-negative bacteria expressin...Objective: To evaluate the in vitro antibacterial properties and the ability to potentiate some common antibiotics effects of the methanol extracts of 11 Cameroonian food plants on 29 Gram-negative bacteria expressing multidrug resistant (MDR) phenotypes. Methods: The antimicrobial activity of the extracts was performed using the broth microdilution method. The phytochemical screening of these extracts was also performed using standard methods. Resalts: Ocimum basilicum, Gnetum africanum and Eucalyptus robusta extracts possessed an antibacterial activity against all the 29 studied bacteria. The extracts from G. africanum and E. robusta were the most active with the lowest minimal inhibitory concentration of 64 p, g/mL on Escherichia coil AG100A for both extracts and also against Klebsiella pneumoniae K24 for G. africanum. When tested in the presence of phenylalanine-arginine 13 -Naphtylamide (PA 13 N), an efflux pump inhibitor, the extract of Thymus vulgafis and E. Robusta showed the best activities on most tested strains. E. Robusta extract showed good synergistic effects, improving the activity of commonly used antibiotics in about 85% of cases. Coaclasion: The overall results obtained provide the baseline information for the use of the tested plants in the treatment of bacterial infections.展开更多
文摘Introduction: Bacterial skin and soft tissue infections (SSTIs) are a cause of frequent inpatient and outpatient care visits whose causative agents are associated with a high antimicrobial resistance burden. For insights on antimicrobial susceptibilities in a rural setting, we examined specimens from suspected SSTIs from two public health facilities in Kenya. We additionally assessed antibiotic use, appropriateness of empiric therapy and risk factors for SSTI. Methodology: Between 2021 and 2023, 265 patients at Kisii and Nyamira County Referral hospitals were enrolled. Wound swabs/aspirates were collected and processed following standard microbiological procedures. Identification and antimicrobial susceptibility were performed using the VITEK 2 Compact platform. Demographic, clinical, and microbiological data were analyzed with R Statistical software. Results: S. aureus was isolated in 16.2% (43/265) of patients with a methicillin resistance (MRSA) proportion of 14% (6/43). While 13/15 drugs elicited susceptibilities ranging from 84% - 100%, penicillin (16%) and trimethoprim-sulfamethoxazole [TMP-SXT] (23%) yielded the lowest susceptibilities. Escherichia coli (n = 33), Klebsiella pneumoniae (n = 8), Pseudomonas aeruginosa (n = 8), and Citrobacter species (n = 4) were the most commonly isolated gram-negative species. Gram-negative strains showed high susceptibilities to most of the tested drugs (71% - 100%) with the exception of ampicillin (18%), TMP-SXT (33%), and first and second generation cephalosporins. Conclusions: The low MRSA prevalence and generally high antibiotic susceptibilities for S. aureus and gram-negative bacteria present opportunities for antibiotic stewardship in the study setting. Diminished susceptibilities against penicillin/ampicillin and TMP-SXT accord with prevailing local data and add a layer of evidence for their cautious empiric use.
文摘Background The prevalence of hospital-acquired infections caused by carbapenem-resistant gram-negative bacteria(CRGNB)is increasing worldwide.Several risk factors have been associated with such infections.The present study aimed to identify risk factors and determine the mortality rates associated with CRGNB infections in intensive care units.Methods This retrospective case-control study was conducted at Erciyes University Hospital(Kayseri,Turkey)between January 2017 and December 2021.Demographic and laboratory data were obtained from the Infection Control Committee data and record system.Patients who had CRGNB infection 48–72 h after hospitalization were assigned to the case group,while those who were not infected with CRGNB during hospitalization formed the control group.Risk factors,comorbidity,demographic data,and mortality rates were compared between the two groups.Results Approximately 1449 patients(8.97%)were monitored during the active follow-up period;of those,1171 patients were included in this analysis.CRGNB infection developed in 14 patients(70.00%)who had CRGNB colonization at admission;in 162(78.26%)were colonized during hospitalization,whereas 515(54.56%)were not colonized.There was no significant difference in age,sex(male/female)or comorbidities.The total length of hospital stay was statistically significantly longer(P=0.001)in the case group(median:24[interquartile range:3–378]days)than the control group(median:16[interquartile range:3–135]days).The rates of colonization at admission(25.5%;vs.10.6%,P=0.001)and mortality(64.4%vs.45.8%,P=0.001)were also significantly higher in the cases than in the control group,respectively.In the univariate analysis,prolonged hospitalization,the time from intensive care unit admission to the development of infection,presence of CRGNB colonization at admission,transfer from other hospitals,previous antibiotic use,enteral nutrition,transfusion,hemodialysis,mechanical ventilation,tracheostomy,reintubation,central venous catheter,arterial catheterization,chest tube,total parenteral nutrition,nasogastric tube use,and bronchoscopy procedures were significantly associated with CRGNB infections(P<0.05).Multivariate analysis identified the total length of stay in the hospital(odds ratio[OR]=1.02;95%confidence interval[CI]:1.01 to 1.03;P=0.001),colonization(OR=2.19;95%CI:1.53 to 3.13;P=0.001),previous antibiotic use(OR=2.36;95%CI:1.53 to 3.62;P=0.001),intubation(OR=1.59;95%CI:1.14 to 2.20;P=0.006),tracheostomy(OR=1.42;95%CI:1.01 to 1.99;P=0.047),and central venous catheter use(OR=1.62;95%CI:1.20 to 2.19;P=0.002)as the most important risk factors for CRGNB infection.Conclusions Colonization,previous use of antibiotics,and invasive interventions were recognized as the most important risk factors for infections.Future research should focus on measures for the control of these parameters.
基金supported by a Grant-in-Aid for Scientific Research(No.25460532 and 26.04912)to Tadashi S.from the Ministry of Education,Culture,Sports,Science,and Technology of Japan
文摘PCR and DNA sequencing were used to screen and characterize integrons and resistance genes in Gram-negative bacteria isolated from seafood products in Japan.A total of 215 Gram-negative bacteria were isolated from local and imported seafood samples collected from retail markets in Hiroshima Prefecture.Class 1 integrons containing gene cassettes encoding resistance to trimethoprim
基金supported by the National Key Research and Development Program of China (2017YFC1600100 and2017YFC1200203)the National Natural Science Foundation of China (81702040)the National Science Foundation of Zhejiang Province,China (LY20H190002)
文摘Humanity is facing an enormous and growing worldwide threat from the emergence of multi-drug-resistant(MDR)Gram-negative bacteria such as Escherichia coli,Klebsiella pneumoniae,and Acinetobacter baumannii.Polymyxin B and E(colistin)constitute the last-line therapies for treating MDR Gram-negative bacteria.Polymyxin is a cationic antibacterial peptide that can destroy the outer membrane of Gram-negative bacteria.With the increasing clinical application of polymyxin,however,there have been many reports of the occurrence of polymyxin-resistant Gram-negative bacteria.This resistance is mainly mediated by the modification or complete loss of lipopolysaccharide(LPS).LPS is also a virulence factor of Gram-negative bacteria,and alterations of LPS may correlate with virulence.Although it is generally believed that the biological costs associated with drug resistance may enable benign susceptible bacteria to overcome resistant bacteria when antibiotic pressure is reduced,some studies have shown that polymyxin-resistant bacteria are associated with higher virulence and greater fitness compared with their susceptible counterparts.To predict the development of polymyxin resis-tance and evaluate interventions for its mitigation,it is important to understand the relative biological cost of polymyxin resistance compared with susceptibility.The impact of polymyxin resistance mecha-nisms on the virulence and fitness of these three Gram-negative bacteria are summarized in this review.
文摘Antibiotic resistant bacteria pathogens remain the leading cause of shellfish borne diseases and a major health threat to humans worldwide. The objectives of this study were to isolate, identify, and determine the antibiotic resistance patterns of Gram-negative bacteria from shellfish. We analyzed a total of 540 shellfish (117 clams, 88 oysters, and 136 periwinkles) samples collected from different vendors at Iko and Douglas Creeks in Akwa Ibom State, South-South Nigeria. Conventional cultural techniques, morphological, biochemical characteristics, and PCR amplification were used to identify the bacterial isolates. Antibiotic susceptibility tests (Kirby-Bauer disk diffusion method) and ESBL phenotype (disk) of the isolates were performed. One hundred and thirty-five (135) Gram-negative bacteria comprising 5 genera and 14 species were detected at a prevalence of: <i>Alcaligenes faecalis</i> <i><b>TRB</b></i>-7 38 (28.2%), <i>Pseudomonas oryzihabitans strain <b>KCB</i>005</b> 16 (11.9%), <i>Paenalcaligenes retgerii strain <b>B</i>5</b> 12 (8.9%) <i>Pseudomonas aeruginosa <b>JB</i>2</b> 10 (7.4%), <i>Providencia stuartii <b>DMC</i>-28b</b> 9 (6.7%), <i>Alcaligenes species <b>TLT</i>151</b> 8 (5.9%), <i>Pseudomonas aeruginosa <b>CIFRI DTSB</i>1</b> 7 (5.2%), <i>Paenalcaligenes species <b>UN</i>24</b> 7 (5.2%), <i>Alcaligenes faecalis <b>BT</i>10</b> 7 (5.2%), <i>Vibrio species strain <b>PrVy</i>108</b> 6 (4.4%), <i>Pseudomonas xiamenensis <b>C</i>10-2</b> 5 (3.7%), <i>Providencia vemicola <b>Bu</i>15_38</b> 4 (2.9%), <i>Pseudomonas anguillisceptica</i> <b>4029</b> 3 (2.2%), and <i>Pseudomonas aeruginosa <b>N</i>15-01092</b> 3 (2.2%). All tested isolates showed various degrees of resistance to the thirteen antimicrobials evaluated. High levels of resistance (100%) to cefepime and imipenem were expressed by all isolates except the <i>Providencia</i> species. For the EBSL indicators, all isolates apart from <i>Alcaligenes</i> species were resistant (100%) to ceftriaxone. All <i>Vibrio</i> species were susceptible to norfloxacin, nalidixic acid, and ceftazidime. The identification of antibiotic resistant Gram-negative bacteria (GNARB) from shellfish in this study highlights the risk of disseminated multi-drug resistance—a serious public health concern.
基金supported by the National Key Research and De-velopment Program of China[grant number 2022YFE0199800]Key R&D Program of Shandong Province[grant number 2020CXGC011305]+1 种基金Shandong Provincial Natural Science Foundation[grant number ZR2020MH308]the National Natural Science Foundation of China[grant number 82,271,658].
文摘Tigecycline serves as a critical“final-resort”antibiotic for treating bacterial infections caused by multidrug-resistant bacteria for which treatment options are severely limited.The increasing prevalence of tigecycline resistance,particularly among Gram-negative bacteria,is a major concern.Various mechanisms have been iden-tified as contributors to tigecycline resistance,including upregulation of nonspecific Resistance Nodulation Divi-sion(RND)efflux pumps due to mutations in transcriptional regulators,enzymatic modification of tigecycline by monooxygenase enzymes,and mutations affecting tigecycline binding sites.This review aims to consolidate our understanding of tigecycline resistance mechanisms in Gram-negative bacteria and offer insights and perspectives for further drug development.
基金supported by National Natural Science Foundation of China(30901021)863the Key Programs for Science and Technology Development of Hubei Province
文摘Over the past years, infectious disease has caused enormous economic loss in pig industry. Among the pathogens, gram negative bacteria not only cause inflammation, but also cause different diseases and make the pigs more susceptible to virus infection. Vaccination, medication and elimination of sick pigs are major strategies of controlling disease. Genetic methods, such as selection of disease resistance in the pig, have not been widely used. Recently, the completion of the porcine whole genome sequencing has provided powerful tools to identify the genome regions that harboring genes controlling disease or immunity. Immunogenornics, which combines DNA variations, transcriptorne, immune response, and QTL mapping data to illustrate the interactions between pathogen and host immune system, will be an effective genomics tool for identification of disease resistance genes in pigs. These genes will be potential targets for disease resistance in breeding programs. This paper reviewed the progress of disease resistance study in the pig focusing on Gram-negative bacilli. Major porcine Gram-negative bacilli and diseases, suggested candidate genes/pathways against porcine Gram-negative bacilli, and distributions of QTLs for immune capacity on pig chromosomes were summarized. Some tools for immunogenomics research were described. We conclude that integration of sequencing, whole genome associations, functional genomics studies, and immune response information is necessary to illustrate molecular mechanisms and key genes in disease resistance.
文摘<b>Introduction:</b> Oral cancer is the third most prominent type of cancer in Bangladesh. During or after oral cancer treatment, immune-compromised cancer patients may be susceptible to an infection by multi-drug-resistant opportunistic microbes. This study aims to identify the prevalent microorganisms from the infected site of oral cancer patients and observe their antibiotic susceptibility pattern. <b>Materials and Methods:</b> Clinical samples were collected from the infected sites of oral cancer patients and healthy people. The swabs collected were placed on nutrient agar slant, then incubated for 24 hours at 37ºC. Bacteria from the slant were inoculated in several selective media (Mannitol Salt Agar Media, KF Streptococcus Agar media, Cetrimide Agar, Eosin Methylene Blue Agar). Several biochemical tests identified opportunistic microorganisms. Finally, the antibiotic susceptibility test was performed by the Kirby Bauer disc diffusion method. <b>Results:</b> The study found that 65.4% of microbes isolated from the patients’ oral cavities were Gram-negative bacteria, and 34.6% were Gram-positive bacteria. Among the patient group isolates (n = 55), the most prevalent organism was <i>Pseudomonas</i> spp. (30;54.54%). Others were <i>Klebsiella</i> spp. (27;49.09%), <i>Staphylococcus</i> spp. (24;43.63%), <i>E. coli</i> (14;25.45%), <i>Streptococcus</i> spp. (14;25.45%), <i>Proteus</i> spp. (12;21.8%) and <i>Enterococcus</i> spp. (6;10.90%). Both Gram-positive and Gram-negative microbes from the patient group have shown high resistance to the commonly used antibiotics. In the control group (n = 50), the most prevalent organism was <i>Staphylococcus</i> spp. (15;30%). Other organisms were <i>Streptococcus</i> spp. (6;12%), <i>Klebsiella</i> spp. (11;22%), <i>E. coli</i> (3;6%), <i>Streptococcus</i> spp. (14;25.45%), <i>Pseudomonas</i> spp. (8;16%). The microbes of the control group showed less resistance to the antibiotics and rather showed sensitivity to them. <b>Conclusion:</b> The study revealed a high prevalence of multi-drug-resistant opportunistic microbes on immune-compromised oral cancer patients compared to microbes isolated from healthy people’s oral cavity.
文摘The study is to identify trends and levels of antibiotic resistance of some common Gram-negative strains over time. The samples were collected from Vietnam Military Hospital 103 between 2014 and 2019. A total of 405 <i>Acinetobacter baumannii</i>., 528 <i>Pseudomonas aeruginosa</i>, 741 <i>Escherichia coli</i>, and 352 <i>Klebsiella pneumoniae</i> strains were identified and antimicrobial susceptibility was by Vitek system and Etest method. The multi-drug resistance (MDR) was major proportion of four common bacteria. In particular, there is a tendency to shift from MDR to Extended drug resistance (XDR) or possibly Pan drug resistant (pPDR). <i>A. baumannii</i> had the highest level of antibiotic resistance, namely, carbapenem (61.5% - 82.5%) and cephalosporin (72.7% - 88.7%). <i>P. aeruginosa</i> resisted most of commonly antibiotics, ranging from 50% to 70%. <i>E. coli</i> had a high resistance with antibiotics like ampicillin (87.2% - 97.6%) and the 3rd generation cephalosporins (up to 79.6%). <i>K. pneumoniae</i> resisted carbapenem from 14.7% to 44.4%, and other antibiotics with the higher rate of 40%. The collected data will be a prerequisite for further studies on mechanisms and factors related to antibiotic resistant bacteria, in order to find out a rational and effective using strategy of antibiotics.
文摘Background: Aerosolized amikacin (AA) is a current option for the management of ventilator-associated pneumonia (VAP) caused by multidrug-resistant Gram-negative bacteria (MDR-GNB), as it is reported that AA could increase the alveolar level of the drug without increasing systemic toxicity. This study aimed to evaluate the efficacy and safety of AA as an adjunctive therapy for VAP caused by MDR-GNB. Methods: In this single-center, double-blind study conducted in a 36-bed general Intensive Care Unit (ICU) in a tertiary hospital from June 2014 to June 2016, 52 ICU patients with confirmed MDR-GNB VAP were randomized to two groups (AA group, n - 27 and placebo group, n = 25). Amikacin (400 rag, q8h) or saline placebo (4 ml, q8h) was aerosolized for 7 days. The attending physician determined the administration of systemic antibiotics for VAP. Patients were tbllowed up for 28 days. Bacteriological eradication, clinical pulmonary infection score (CP1S), and serum creatinine were assessed on day 7 of therapy. New resistance to amikacin, cure rate of VAP, weaning rate, and mortality were assessed on day 28. Results: The baseline characteristics of patients in both groups were similar. At the end of the treatment, 13 of the 32 initially detected bacterial isolates were eradicated in AA group, compared to 4 of 28 in placebo group (41% vs. 14%, P - 0.024). As for patients, 11 of 27 patients treated with AA and 4 of 25 patients treated with placebo have eradication (41% vs. 16%, P = 0.049). The adjunction of AA reduced CPIS (4.2 ± 1.6 vs. 5.8 ± 2.1, P = 0.007). New drug resistance to amikacin and the change in serum creatinine were not detected in AA group. No significant differences in the clinical cure rate in survivors (48% vs. 35%, P = 0.444), weaning rate (48% vs. 32%, P = 0.236), and mortality (22% vs. 32%, P = 0.427) were detected between the two groups on day 28. Conclusions: As an adjunctive therapy of MDR-GNB VAP, AA successfully eradicated existing MDR organisms without inducing new resistance to amikacin or change in serum creatinine. However, the improvement of mortality was not found.
文摘Objective: To evaluate the in vitro antibacterial properties and the ability to potentiate some common antibiotics effects of the methanol extracts of 11 Cameroonian food plants on 29 Gram-negative bacteria expressing multidrug resistant (MDR) phenotypes. Methods: The antimicrobial activity of the extracts was performed using the broth microdilution method. The phytochemical screening of these extracts was also performed using standard methods. Resalts: Ocimum basilicum, Gnetum africanum and Eucalyptus robusta extracts possessed an antibacterial activity against all the 29 studied bacteria. The extracts from G. africanum and E. robusta were the most active with the lowest minimal inhibitory concentration of 64 p, g/mL on Escherichia coil AG100A for both extracts and also against Klebsiella pneumoniae K24 for G. africanum. When tested in the presence of phenylalanine-arginine 13 -Naphtylamide (PA 13 N), an efflux pump inhibitor, the extract of Thymus vulgafis and E. Robusta showed the best activities on most tested strains. E. Robusta extract showed good synergistic effects, improving the activity of commonly used antibiotics in about 85% of cases. Coaclasion: The overall results obtained provide the baseline information for the use of the tested plants in the treatment of bacterial infections.