Efficacy of cefoperazone/sulbactam for ESBL-producing Escherichia coli and Klebsiella pneumoniae bacteraemia and the factors associated with poor outcomes.

OBJECTIVE: We aimed to assess the efficacy of cefoperazone/sulbactam (CPZ/SUL) in extended-spectrum ß-lactamase (ESBL)-producing Enterobacterales infections and identify factors influencing outcomes. METHODS: This retrospective multicentre study was conducted in Taiwan (January 2015 to December 2020) and examined the efficacy of CPZ/SUL treatment in ESBL-producing Enterobacterales bacteraemia. The minimum inhibitory concentrations (MICs) were determined using agar dilution; ESBL/AmpC genes were detected using polymerase chain reaction. The primary outcome was clinical success, whereas the secondary outcome was 30-day mortality. Clinical success was defined as the complete resolution of clinical signs and symptoms of K. pneumoniae or E. coli infection, with no evidence of persistent or recurrent bacteraemia. The factors influencing outcomes were identified using a multivariate analysis. RESULTS: CPZ/SUL demonstrated a clinical success rate of 82.7% (91/110) in treating ESBL-producing Enterobacterales bacteraemia, with a 30-day mortality rate of 9.1% (10/110). Among 110 ESBL-producing isolates, a high clinical success rate was observed at an MIC of ≤32/32 mg/L. Multivariate analysis revealed that a Charlson comorbidity index (CCI) of ≥6 was associated with lower clinical success [odds ratio (OR): 5.80, 95% confidence interval (CI): 1.15-29.14, P = 0.033]. High Sequential Organ Failure Assessment scores (≥6) were significantly associated with increased 30-day mortality (OR: 14.34, 95% CI: 1.45-141.82, P = 0.023). DISCUSSION: CPZ/SUL demonstrated a clinical success rate of 82.7% (91/110) in treating ESBL-producing Enterobacterales bacteraemia. Treatment success was evident when the CPZ and SUL MIC was ≤32/32 mg/L. Comorbidities (CCI ≥6) were associated with lower clinical success, while disease severity (Sequential Organ Failure Assessment score ≥6) correlated with higher mortality.

Antimicrobial Susceptibility of E. coli Isolates from Intra-Abdominal Infections in the Asia-Pacific Region: Trends in Ciprofloxacin, Ceftriaxone, Cefepime, and Piperacillin/Tazobactam Susceptibility.

Purpose: To investigate the antibiotic susceptibility of Escherichia coli isolates in patients diagnosed with intra-abdominal infections (IAIs) in the Asia-Pacific region. Patients and Methods: This study was conducted at 50 medical hospitals across 9 countries/regions as part of the Study for Monitoring Antimicrobial Resistance Trends (SMART) surveillance program from 2014 to 2018. Nonduplicate isolates of aerobic and facultative gram-negative bacilli were collected and processed for further antimicrobial susceptibility testing. Results: A total of 10,709 isolates were collected, with E. coli (n=4737, 44.2%) being the leading pathogen causing IAIs, followed by Klebsiella pneumoniae (n=2429, 22.7%) and Pseudomonas aeruginosa (n=931, 8.7%). Community-associated (CA) E. coli isolates generally exhibited higher susceptibility rates for most antibiotics than hospital-associated (HA) isolates. In countries/regions other than Hong Kong, South Korea, and Singapore, HA isolates displayed lower susceptibility rates for multiple classes (≥4) of antibiotics. Among the commonly used antibiotics in IAIs, the overall susceptibility rate for ciprofloxacin was low, with an average of 41.3%. Ceftriaxone susceptibility rates in all selected countries were below 80% starting in 2018, ranging from 23.3% to 75.8%. The cefepime susceptibility rates varied across regions, with consistently reduced susceptibility ranging from 45.5% to 57.8% in India, Thailand, and Vietnam. Piperacillin/tazobactam demonstrated effectiveness against E. coli isolates in almost all countries except India, with a downward trend observed in the Philippines and Taiwan. Carbapenems remained effective against more than 90% of E. coli isolates, except in India. Conclusion: Prudent use of fluoroquinolones and ceftriaxone is advised when treating both CA and HA IAIs in the Asia-Pacific region. The low susceptibility rate of cefepime in India, Thailand, and Vietnam needs careful consideration in its administration. Moreover, the increase in nonsusceptibility to piperacillin/tazobactam in the Philippines and Taiwan poses a potential risk that should be closely monitored.

The effect of Lactobacillus with prebiotics on KPC-2-producing Klebsiella pneumoniae.

Objectives: This study investigated the inhibitory effect of Lactobacillus spp. with prebiotics against Klebsiella pneumoniae carbapenemase-2 (KPC-2)-producing Klebsiella pneumoniae using both in vitro experiments and animal models. Methods: Thirty-three Lactobacillus spp. strains were confirmed by 16S rDNA sequencing, and four different PFGE genotyped KPC-2-producing K. pneumoniae strains were selected for investigation. In vitro studies, including broth microdilution assays, changes in pH values in lactobacilli cultures with different prebiotics, time-kill tests of Lactobacillus spp. against KPC-2-producing K. pneumoniae and further in vivo Lactobacillus alone or in combination with prebiotics against KPC-2-producing K. pneumoniae in an animal model, were performed. Results: The lower pH value of the cell-free supernatant was associated with a lower minimal inhibitory percentage of the Lactobacillus strain against KPC-2-producing K. pneumoniae. Furthermore, lactulose/isomalto-oligosaccharide/inulin and fructo-oligosaccharide can enhance the inhibitory effect of all 107 CFU/ml Lactobacillus strains against KPC001. Three Lactobacillus strains (LYC1154, LYC1322, and LYC1511) that could be persistently detected in the stool were tested for their ability to reduce the amount of KPC001 in the feces individually or in combination. A significantly better effect in reducing the amount of KPC001 was observed for the combination of three different Lactobacillus species than for each of them alone. Furthermore, their inhibitory effect was enhanced after adding lactulose or isomalto-oligosaccharide (both p < 0.05). Conclusion: This study demonstrates the inhibitory effect of probiotic Lactobacillus, including LYC1154, LYC1322, and LYC1511, with prebiotics such as lactulose or isomalto-oligosaccharide against the colonization of KPC-2-producing K. pneumoniae.

Gaps in antimicrobial stewardship programmes in Asia: a survey of 10 countries.

Objectives: To determine antimicrobial stewardship (AMS) programme practices in Asian secondary- and tertiary-care hospitals. Methods: AMS programme team members within 349 hospitals from 10 countries (Cambodia, India, Indonesia, Japan, Malaysia, Pakistan, the Philippines, Taiwan, Thailand and Vietnam) completed a questionnaire via a web-based survey link. The survey contained questions as to whether 12 core components deemed essential for AMS programmes were implemented. Results: Overall, 47 (13.5%) hospitals fulfilled all core AMS programme components. There was a mean positive response rate (PRR) of 85.6% for the responding countries in relation to a formal hospital leadership statement of support for AMS activities, but this was not matched by budgeted financial support for AMS activities (mean PRR 57.1%). Mean PRRs were ≥80.0% for the core AMS team comprising a physician or other leader responsible for AMS activities, a pharmacist and infection control and microbiology personnel. Most hospitals had access to a timely and reliable microbiology service (mean PRR 90.4%). Facility-specific antibiotic treatment guidelines for common infections (mean PRR 78.7%) were in place more often than pre-authorization and/or prospective audit and feedback systems (mean PRR 66.5%). In terms of AMS monitoring and reporting, PRRs of monitoring specific antibiotic use, regularly publishing AMS outcome measures, and the existence of a hospital antibiogram were 75.1%, 64.4% and 77.9%, respectively. Conclusions: Most hospitals participating in this survey did not have AMS programmes fulfilling the requirements for gold standard AMS programmes in hospital settings. Urgent action is required to address AMS funding and resourcing deficits.

Correlation Between Cefoperazone/Sulbactam MIC Values and Clinical Outcomes of Escherichia coli Bacteremia.

INTRODUCTION: The clinical efficiency of cefoperazone/sulbactam (CPZ/SUL) against Escherichia coli bacteremia was unknown. This study aimed to explore the relationship between CPZ/SUL MIC values and clinical outcomes in Escherichia coli bacteremia. METHODS: A multicenter, retrospective, observational cohort study was conducted in Taiwan between January 2015 and December 2020. Patients treated with CPZ/SUL for E. coli bacteremia were enrolled in the analysis. The CPZ/SUL MICs were determined by using the agar dilution method. The primary outcome was 30-day mortality. RESULTS: Among 247 isolates, 160 (64.8%) isolates were susceptible, 8 (3.2%) were intermediate, and 79 (32.0%) were resistant to cefoperazone. The activity of cefoperazone against cefoperazone-non-susceptible E. coli (n = 87) was restored upon combination with sulbactam, with susceptibility ranging from 0% to 97.7%. The 30-day mortality was 4.5% (11/247) and overall clinical success rate was 91.9% (227/247). Multivariate Cox proportional-hazards model revealed that heart failure [adjusted relative risk (ARR), 5.49; 95% confidence interval (CI) 1.31-23.02; p = 0.020], malignancy (ARR 7.50; 95% CI 2.02-27.80; p = 0.003), SOFA score (ARR 1.29; 95% CI 1.09-1.52; p = 0.003), and CPZ/SUL MIC ≥ 64 mg/L (ARR 11.31; 95% CI 1.34-95.52; p = 0.026) were independently associated with 30-day mortality. No statistically significant differences in 30-day mortality were found between groups with or without cefoperazone susceptibility (3.4% vs. 5.0%, p = 0.751, respectively). CONCLUSIONS: Patients with E. coli bacteremia who were treated with CPZ/SUL had a favorable outcome when the MICs of the isolates were ≤ 16 mg/L and a high risk of mortality with MICs ≥ 64 mg/L.

Distribution of ß-lactamases and emergence of carbapenemases co-occurring Enterobacterales isolates with high-level antibiotic resistance identified from patients with intra-abdominal infection in the Asia-Pacific region, 2015-2018.

PURPOSE: In this study, we aimed to assess the geographic distribution and molecular characteristics of ß-lactamases among Enterobacterales isolates causing intra-abdominal infections (IAIs) from 2015 to 2018 in the Asia-Pacific region. METHOD: Isolates were investigated for extended-spectrum ß-lactamases (ESBLs), AmpC ß-lactamases, and carbapenemases using multiplex PCR assays and full-gene DNA sequencing. RESULT: A total of 832 Enterobacterales isolates from 8 different countries with ß-lactamase genes were analysed. Plasmid-mediated ESBLs and AmpC ß-lactamases were encoded in 598 (71.9 %) and 314 (37.7 %) isolates, respectively. In 710 (85.3 %) carbapenemase-negative isolates, positivity for both AmpC ß-lactamases and ESBLs was identified in 51 (8.5 %) Escherichia coli and 24 (3.4 %) Klebsiella pneumoniae isolates. The most prevalent countries were Taiwan and Vietnam, and the co-occurrence of CMY/CTX-M in E. coli and DHA-1/ESBLs in K. pneumoniae was predominant. All isolates showed high susceptibility to colistin, but susceptibility to carbapenems varied among different resistance mechanism combinations. Among 122 (14.7 %) isolates encoding carbapenemase, NDM (n = 67, including 64.2 % NDM-1) was the most common, followed by the OXA-48-type (n = 49), KPC (n = 24) and IMP (n = 4). The most prevalent country was Thailand (n = 44), followed by Vietnam (n = 35) and the Philippines (n = 21). Twenty-two isolates were found to encode multiple carbapenemases, 16 of which were collected from Thailand and harbored NDM-1, OXA-232 and CTX-M-15. Despite high susceptibility to amikacin, susceptibility to colistin was only 56 %. CONCLUSION: The emergence of carbapenem-non-susceptible AmpC/ESBL co-occurring Enterobacterales and colistin non-susceptible carbapenemases co-occurring K. pneumoniae highlights potential therapeutic challenges in the Asia-Pacific region.

Molecular characteristics and in vitro effects of antimicrobial combinations on planktonic and biofilm forms of Elizabethkingia anophelis.

OBJECTIVES: To investigate the in vitro activity of antibiotics against clinical Elizabethkingia anophelis isolates and to find a suitable antibiotic combination with synergistic effects to combat antibiotic-resistant E. anophelis and its associated biofilm. METHODS: E. anophelis isolates were identified by 16S rRNA sequencing; 30 strains with different pulsotypes were identified and the MIC, antibiotic resistance mechanism, antibiotic combination activity and killing effects of antimicrobial agents on biofilms of these strains were determined. RESULTS: All E. anophelis isolates were susceptible to minocycline and cefoperazone/sulbactam (1:1). More than 90% of clinical isolates were susceptible to cefoperazone/sulbactam (1:0.5), piperacillin/tazobactam and rifampicin. Some novel mutations, such as gyrA G81D, parE D585N and parC P134T, that have never been reported before, were identified. The synergistic effect was most prominent for the combination of minocycline and rifampicin, with 93.3% of their FIC index values ≤0.5, and no antagonism was observed using the chequerboard method. This synergistic effect between minocycline and rifampicin was also observed using time-killing methods for clinical E. anophelis isolates at both normal inoculum and high inoculum. Twenty-nine isolates tested positive for biofilm formation. Minocycline remained active against biofilm-embedded and biofilm-released planktonic E. anophelis cells; however, the enhanced effect of minocycline by adding rifampicin was only observed at 24 h (not at 72 and 120 h). CONCLUSIONS: Although E. anophelis was resistant to many antibiotics and could exhibit biofilm formation, minocycline showed potent in vitro activity against this pathogen and its associated biofilm.

Antimicrobial ability and mechanism analysis of Lactobacillus species against carbapenemase-producing Enterobacteriaceae.

BACKGROUND: This study aims to investigate the antimicrobial ability and mechanism analysis of Lactobacillus species against carbapenemase-producing Enterobacteriaceae (CPE). METHODS: Five Lactobacillus spp. strains and 18 CPE clinical isolates were collected. Their anti-CPE effects were assessed by agar well diffusion and broth microdilution assay, as well as time-kill test. Finally, the specific anti-CPE mechanism, especially for the effect of organic acids was determined using broth microdilution method. RESULTS: All of five Lactobacilli isolates displayed the potent activity against most CPE isolates with mean zones of inhibition ranging 10.2-21.1 mm. The anti-CPE activity was not affected by heating, catalase, and proteinase treatment. Under the concentration of 50% LUC0180 cell-free supernatant (CFS), lactic acid, and mix acid could totally inhibit the growth of carbapenem-resistant Klebsiella pneumoniae (CPE0011), and acetic acid could inhibit 67.8%. In contrast, succinic acid and citric acid could not inhibit the growth of CPE0011. While we decreased the concentration to 25%, only lactic acid and mix acid displayed 100% inhibition. In contrast, succinic acid, citric acid and acetic acid did not show any inhibitory effect. CONCLUSIONS: Lactobacillus strains exhibit potent anti-CPE activity, and lactic acid produced by Lactobacillus strains is the major antimicrobial mechanism.

Does Antimicrobial Therapy Affect Mortality of Patients with Carbapenem-Resistant Klebsiella pneumoniae Bacteriuria? A Nationwide Multicenter Study in Taiwan.

Few clinical studies have previously discussed patients with carbapenem-resistant Klebsiella pneumoniae (CRKP) bacteriuria. This study aimed to assess the effect of antimicrobial therapy on the mortality of patients with CRKP bacteriuria. Hospitalized adults with CRKP bacteriuria were enrolled retrospectively from 16 hospitals in Taiwan during 2013 and 2014. Critically ill patients were defined as those with an Acute Physiology and Chronic Health Evaluation (APACHE) II score ≥ 20. Multivariate Cox regression analysis was used to determine independent risk factors for 14- and 28-day mortality. Of 107 patients with CRKP bacteriuria, the 14-day and 28-day mortality was 14.0% and 25.2%, respectively. Thirty-three patients received appropriate antimicrobial therapy. In the multivariate Cox regression analysis, the APACHE II score ≥ 20 was the only independent risk factor for 14-day mortality (hazard ratio [HR]: 6.15, p = 0.024). APACHE II score ≥ 20 (HR: 3.05, p = 0.018) and male sex (HR: 2.57, p = 0.037) were associated with 28-day mortality. Among critically ill patients with CRKP bacteriuria, appropriate antimicrobial therapy was not associated with 14-day or 28-day survival. In conclusion, in patients with CRKP bacteriuria, the use of appropriate antimicrobial therapy was not an independent factor associated with reduced mortality. Our findings may inform future antibiotic stewardship interventions for bacteriuria caused by multidrug resistant pathogens.

Tigecycline Therapy for Infections Caused by Extended-Spectrum ß-Lactamase-Producing Enterobacteriaceae in Critically Ill Patients.

: We aimed to evaluate tigecycline on the clinical effectiveness in treating complicated skin and soft tissue infections (cSSTI), complicated intra-abdominal infections (cIAI), and pneumonia, caused by extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae, as data are limited. From three medical centers in Taiwan, we retrospectively studied the cSSTI, cIAI, and/or pneumonia caused by ESBL-producing Enterobacteriaceae. Among the 71 patients, including 39 patients infected with Klebsiella pneumoniae, 30 infected with Escherichia coli and others, the clinical success rate of tigecycline-based therapy was 80%-90% for pneumonia and cSSTI caused by E. coli and 50%-60% for cIAI caused by K. pneumoniae and E. coli. Microbiological and clinical outcome of pneumonia caused by carbapenem-resistant K. pneumoniae was poor. Univariate Cox analysis showed that dyspnea, SOFA score, septic shock, thrombocytopenia, prolonged prothrombin time, and lesser microbiological eradication were significant factors associated with 30-day mortality after the end of therapy. Cox regression proportional hazards model revealed dyspnea and a SOFA score > 8 to be independently associated with time to death. For ESBL producers, tigecycline showed good effects for cSSTI and pneumonia by E. coli, ordinary for cIAI, but ineffective for pneumonia by K. pneumoniae. Dyspnea and a high SOFA score predict a poor outcome.

UvrY is required for the full virulence of Aeromonas dhakensis.

Aeromonas dhakensis is an emerging human pathogen which causes fast and severe infections worldwide. Under the gradual pressure of lacking useful antibiotics, finding a new strategy against A. dhakensis infection is urgent. To understand its pathogenesis, we created an A. dhakensis AAK1 mini-Tn10 transposon library to study the mechanism of A. dhakensis infection. By using a Caenorhabditis elegans model, we established a screening platform for the purpose of identifying attenuated mutants. The uvrY mutant, which conferred the most attenuated toxicity toward C. elegans, was identified. The uvrY mutant was also less virulent in C2C12 fibroblast and mice models, in line with in vitro results. To further elucidate the mechanism of UvrY in controlling the toxicity in A. dhakensis, we conducted a transcriptomic analysis. The RNAseq results showed that the expression of a unique hemolysin ahh1 and other virulence factors were regulated by UvrY. Complementation of Ahh1, one of the most important virulence factors, rescued the pore-formation phenotype of uvrY mutant in C. elegans; however, complementation of ahh1 endogenous promoter-driven ahh1 could not produce Ahh1 and rescue the virulence in the uvrY mutant. These findings suggest that UvrY is required for the expression of Ahh1 in A. dhakensis. Taken together, our results suggested that UvrY controls several different virulence factors and is required for the full virulence of A. dhakensis. The two-component regulator UvrY therefore a potential therapeutic target which is worthy of further study.

In Vitro Synergy of Pongamia pinnata Extract in Combination with Antibiotics for Inhibiting and Killing Methicillin-Resistant Staphylococcus aureus.

AIMS: Currently, we face the serious problem of multiple drug-resistant pathogens. The development of new antimicrobial agents is very costly and time-consuming. Therefore, the use of medicinal plants as a source of alternative antibiotics or for enhancing antibiotic effectiveness is important. METHODS: The antibacterial effects of aqueous extracts of the seed coat of Pongamia pinnata (Linn.) Pierre in combination with several antibiotics against methicillin-resistant Staphylococcus aureus (MRSA) were tested by broth dilution, checkerboard, and time-kill methods. RESULTS: For the combinations of P. pinnata with ampicillin, meropenem, cefazolin, cefotaxime, cefpirome, and cefuroxime, 70% to 100% were synergistic, with a fractional inhibitory concentration (FIC) index of < 0.5. For the time-kill method with 0.5× minimum inhibitory concentration (MIC) of P. pinnata in combination with 8, 4, 2, and 1 µg mL-1 of the various antibiotics, almost all of the combinations showed synergistic effects, even with the lowest concentrations of P. pinnata, except for aztreonam. No antagonistic effect was observed for these combinations. CONCLUSIONS: Based on these findings, aqueous seed coat extracts of P. pinnata have good potential for the design of new antimicrobial agents.

In Vitro Antimicrobial Activity of Various Cefoperazone/Sulbactam Products.

: This study aims to assess the in vitro activity of different samples of cefoperazone/sulbactam (CFP/SUL) against multidrug-resistant organisms (MDROs). Clinical isolates of extended-spectrum ß-lactamase (ESBL)-Escherichia coli, ESBL-Klebsiella pneumoniae, carbapenem-resistant Acinetobacter baumannii (CR-AB), and carbapenem-resistant Pseudomonas aeruginosa (CR-PA) were collected. The minimum inhibitory concentration (MIC) and time-killing methods were used to assess and compare the in vitro activities of different samples of cefoperazone/sulbactam (CFP/SUL) against these MDROs. For ESBL-E. coli, ESBL-K. pneumoniae, and CR-PA, product C had smaller variations than product A and B (p < 0.05). For CR-AB, product B had the largest variation compared to the other two products (p < 0.05). In the time-killing studies, significant differences among the products when used at 16/16 µg/mL were noted for ESBL-E. coli, ESBL-K. pneumoniae, and CR-AB isolates. In conclusion, this study demonstrated the significantly different activity of different products of CFP/SUL against MDROs.

Activity of ceftolozane-tazobactam against Gram-negative pathogens isolated from lower respiratory tract infections in the Asia-Pacific region: SMART 2015-2016.

The aim of this study was to investigate the susceptibility of respiratory Gram-negative bacteria to ceftolozane/tazobactam and other antibiotics in the Asia-Pacific region during 2015-2016. MICs were determined using the CLSI standard broth microdilution method and interpreted accordingly. Pseudomonas aeruginosa (1574 isolates), Klebsiella pneumoniae (1226), Acinetobacter baumannii (627) and Escherichia coli (476) accounted for 73.1% of 5342 Gram-negative respiratory pathogens. Susceptibility to ceftolozane/tazobactam of individual Enterobacteriaceae was >80%, except for Enterobacter cloacae (76.6%). Ceftolozane/tazobactam inhibited 81.9% of K. pneumoniae and 91.9% of E. coli, with respective MIC50/MIC90 values of 0.5/>32 and 0.25/2 mg/L. For carbapenem-susceptible, ESBL-producing K. pneumoniae and E. coli, susceptibility was 65.5% and 93.3%, respectively, and respective MIC50/MIC90 values were 2/>32 and 0.5/2 mg/L. BlaCTX-M-1 group was most prevalent in selected ESBL-producing K. pneumoniae (40 of 54 isolates) and E. coli (15 of 22 isolates), with ceftolozane/tazobactam susceptibility rates of 50% and 80%, respectively. BlaSHV-ESBL was the second most prevalent, and ceftolozane/tazobactam inhibited 20% of 20 K. pneumoniae isolates with blaSHV-ESBL. The only effective antibiotics for carbapenem-non-susceptible K. pneumoniae (111 isolates) and E. coli (24 isolates) were amikacin and colistin. Ceftolozane/tazobactam was effective against almost all tested P. aeruginosa and carbapenem-non-susceptible strains, with susceptibility of 92.3% and 72.8%, respectively; the respective MIC50/MIC90 values were 1/4 and 2/>32 mg/L. The high susceptibility of ceftolozane/tazobactam remained in different age groups, patient locations, recovery times and countries, except Vietnam. In conclusion, ceftolozane/tazobactam was effective against most respiratory Gram-negative pathogens in the Asia-Pacific region; however, the emergence of carbapenem resistance mandates ongoing surveillance.

The Potential Role of Sulbactam and Cephalosporins Plus Daptomycin Against Daptomycin-Nonsusceptible VISA and H-VISA Isolates: An in Vitro Study.

This study assesses the synergistic effect of the combination of cephalosporins and sulbactam with daptomycin against daptomycin-nonsusceptible, vancomycin-intermediate resistant Staphylococcus aureus (VISA) or heterogeneous vancomycin-intermediate S. aureus (h-VISA) isolates. The in vitro activity of daptomycin against daptomycin-nonsusceptible VISA/h-VISA isolates after adding cephalosporins with or without sulbactam was evaluated. The MIC of daptomycin against the VISA/h-VISA isolates was reduced after adding cephalosporins to daptomycin. Except for one VISA and two h-VISA isolates, the other VISA/h-VISA isolates became daptomycin-susceptible (MICs 1 mg/L). After adding sulbactam to each daptomycin/cephalosporin combination, the MIC of daptomycin against the VISA/h-VISA isolates decreased for 5 (33.3%), 6 (40.0%), 6 (40.0%), and 6 (40.0%) isolates with the cefazolin, cefmetazole, cefotaxime, and cefepime combinations, respectively. Synergism using the checkerboard method was noted in 100% of cefazolin and cefotaxime combinations and 87% and 80% of cefmetazole and cefepime combinations for all the VISA and h-VISA isolates. With the addition of sulbactam, synergism was noted in 100% of cefazolin, cefmetazole, and cefotaxime combinations and 93% of the cefepime combinations for all the VISA and h-VISA isolates. Almost all the FICs for the three-drug combinations were lower than those for the two-drug combinations. Using time-killing methods, a synergistic effect against five h-VISA isolates was observed. A synergistic effect of daptomycin, sulbactam, and each cephalosporin was observed for all VISA isolates. In conclusion, the activity of daptomycin against daptomycin-nonsusceptible VISA/h-VISA isolates can be enhanced by adding cephalosporins, and partially further promoted by sulbactam.

Resistance mechanisms and molecular epidemiology of carbapenem-nonsusceptible Escherichia coli in Taiwan, 2012-2015.

PURPOSE: This study aimed to investigate the resistance mechanisms and molecular epidemiology of carbapenem-nonsusceptible Escherichia coli (CnsEC) in Taiwan. PATIENTS AND METHODS: From 2012 to 2015, 237 E. coli isolates with minimum inhibitory concentrations of imipenem or meropenem >1 µg/mL were collected in a nationwide surveillance and subjected to polymerase chain reaction (PCR) for carbapenemase, AmpC-type ß-lactamase, and extended spectrum ß-lactamase (ESBL) genes. We evaluated outer membrane proteins (OmpF and OmpC) loss and conducted multilocus sequence typing and pulsed-field gel electrophoresis (PFGE). Isolates that were resistant to all carbapenems were designated as pan-carbapenem-resistant E. coli (pCREC) in this study. RESULTS: The predominant resistance mechanism of CnsEC in Taiwan was the CMY-2 ß-lactamase in combination with OmpF and OmpC loss. Sequence type 131 was the most prevalent type (29.2%). Among 237 CnsEC isolates, 106 (44.7%) isolates were pCREC and 18 (7.59%) produced carbapenemase. The prevalence of carbapenemases increased from 6% in 2012 to 11.36% in 2015. Various carbapenemases including KPC-2, IMP-8, NDM-1, NDM-5, VIM-1, OXA-48, and OXA-181 were identified, with NDM-1 being the most common (38.9%) carbapenemase. Comparison between pCREC and non-pCREC among the non-carbapenemase-producing CnsEC isolates revealed SHV, CMY, co-carriage of SHV and CTX-M and concurrent loss of both OmpF and OmpC were more commonly detected in the pCREC group. PFGE revealed no nationwide clonal spread of carbapenemase-producing E. coli. CONCLUSION: NDM-1 was the most common carbapenemase and combination of CMY-2 and concurrent OmpF and OmpC porin loss was the most prevalent resistance mechanism in CnsEC in Taiwan.

Antimicrobial Activity of Lactobacillus Species Against Carbapenem-Resistant Enterobacteriaceae.

OBJECTIVE: This study aims to identify suitable lactobacilli that have anti-carbapenem-resistant Enterobacteriaceae (CRE) activity with in vitro tolerance to pepsin and bile salts. METHODS: Fifty-seven Lactobacillus spp. strains encompassing nine species were collected for investigation. Their viabilities in the presence of pepsin and bile salts were tested using tolerance tests. Their anti-CRE effects were assessed by agar well diffusion and broth microdilution assay, as well as time-kill test. RESULTS: Of the 57 Lactobacillus isolates collected, 31 had a less than 2-log reduction in their viability in both pepsin and bile salt tolerance tests. Of these 31 isolates, 5 (LUC0180, LUC0219, LYC0289, LYC0413, and LYC1031) displayed the greatest anti-CRE activity with a CRE zone of inhibition greater than 15 mm in agar well diffusion assays. The minimal inhibitory percentages of supernatants from these five strains against CREs ranged from 10 to 30%. With the exception of LUC0180, which had a minimal bactericidal percentage ≥ 40%, the bactericidal percentage of all the strains ranged from 20 to 40%. The inhibitory effect of the cell-free culture supernatants from these Lactobacillus strains did not change after heating but was abolished as the pH changed to 7.0. After a 24-h incubation, five of the Lactobacillus strains at a concentration of 108 CFU/ml totally inhibited the growth of carbapenem-resistant Escherichia coli (CRE316) and Klebsiella pneumoniae (CRE632). After a 48-h incubation, the growth of CRE316 was completely inhibited under each concentration of lactobacilli based on time-kill test. Furthermore, when the concentration of lactobacilli was at 108 CFU/ml, the decline in pH was faster than at other concentrations. CONCLUSION: Some Lactobacillus strains exhibit anti-CRE activity, which suggests potential applications for controlling or preventing CRE colonization or infection.

Randomized Noninferiority Trial of Cefoperazone-Sulbactam versus Cefepime in the Treatment of Hospital-Acquired and Healthcare-Associated Pneumonia.

Cefoperazone, a third-generation cephamycin with broad-spectrum antibacterial activity and the ability to permeate bacterial cell membranes, is active against commonly encountered multidrug-resistant pathogens for hospital-acquired pneumonia (HAP) and health care-associated pneumonia (HCAP). To clarify the clinical effects of cefoperazone-sulbactam in the treatment of HAP and HCAP, we conducted an open-label, randomized, noninferiority trial that recruited patients aged ≥18 years suffering HAP/HCAP. Participants were randomly assigned to the cefoperazone-sulbactam (2 g of each per 12 h) or cefepime (2 g per 12 h) arm. Clinical and microbiological responses were evaluated at early posttherapy and test-of-cure visits. Recruited patients were allocated to subpopulations for intent-to-treat (n = 154), per-protocol (n = 147), and safety (n = 166) analyses. Intent-to-treat analysis demonstrated that (i) at the early posttherapy visit, 87.3% of patients receiving cefoperazone-sulbactam and 84.3% of patients receiving cefepime achieved clinical improvement or cure (risk difference of 3.0%; 95% confidence interval [CI], -9.0% to 15.0%), and (ii) at the test-of-cure visit, 73.1% of patients receiving cefoperazone-sulbactam and 56.8% of patients receiving cefepime were assessed as cured (risk difference of 16.3%; 95% CI, 0.0% to 33.0%). These results indicated the noninferiority of cefoperazone-sulbactam to cefepime, which was confirmed by per-protocol analysis. The chest radiographic consolidation/infiltration resolution rate, microbiological eradiation rate, and percentage of adverse events were comparable in both groups. Serious adverse events were rare, and none was judged to be related to the study drugs. Cefoperazone-sulbactam at 2 g every 12 h was noninferior to cefepime at 2 g every 2 h for patients with HCAP.

Indocyanine Green-Mediated Photodynamic Therapy Reduces Methicillin-Resistant Staphylococcus aureus Drug Resistance.

Methicillin-resistant Staphylococcus aureus (MRSA) skin-wound infections are associated with considerable morbidity and mortality. Indocyanine green (ICG), a safe and inexpensive dye used in clinical imaging, can be activated by near-infrared in photodynamic therapy (PDT) and photothermal therapy (PTT) to effectively kill MRSA. However, how this treatment affects MRSA drug sensitivity remains unknown. The drug-sensitivity phenotypes, bacterial growth rate, and cell-wall thickness of three MRSA strains were analyzed after ICG-PDT. Drug-resistant gene expressions were determined by polymerase chain reaction (PCR) and quantitative reverse transcription (qRT)-PCR. Related protein expressions were examined with immunoblotting. Drug sensitivity was further evaluated in animal models. MRSA that survived the treatment grew faster, and the cell wall became thinner compared to parental cells. These cells became more sensitive to oxacillin, which was partly related to mecA complex gene deletion. Skin necrosis caused by ICG-PDT-treated MRSA infection was smaller and healed faster than that infected with parental cells. With oxacillin therapy, no bacteria could be isolated from mouse lung tissue infected with ICG-PDT-treated MRSA. ICG-PDT drives MRSA toward an oxacillin-sensitive phenotype. It has the potential to develop into an alternative or adjuvant clinical treatment against MRSA wound infections.