Banks can be as powerful and valued as the big technology firms. Yes, those trillion-dollar titans.

Stokvels are an important strategy for financial survival, so it's crucial to find a way to make them work during the pandemic, says Dr Norman Chivasa.

Authorities unable or unwilling to face up to a reality that might reveal their own shortcomings and ineptitude, usually resort to pinpointing a scapegoat. This year, Covid-19 fits that bill, says Terry Bell.

The furore surrounding the arrival of over 200 Cuban medical doctors in South Africa to fight the coronavirus has highlighted a failure on the part of the SA government to explain the nature and drivers of our country’s relationship with Cuba, says Mills Soko.

For the first time in 130 years, there will be no rallies and marches to celebrate what began as a campaign for an eight-hour working day.

Where businesses are fighting to survive, agility is the name of the game, says Mignon Reynecke.

Strategic partnerships could be used to create win-win outcomes, says Sifiso Skenjana.

Trees, shrubs and woody vines are among the top food sources for honey bees in urban environments, according to an international team of researchers. By using honey bees housed in rooftop apiaries in Philadelphia, the researchers identified the plant species from which the honey bees collected most of their food, and tracked how these food resources changed from spring to fall. The findings may be useful to homeowners, beekeepers and urban land managers who wish to sustain honey bees and other bee and pollinator species.

Peacebuilding cannot succeed if half the population is excluded from the process. Crisis Group’s research in Sudan, Congo (DRC) and Uganda suggests that peace agreements, post-conflict reconstruction, and governance do better when women are involved.

The approaching elections could be important steps toward reviving democracy in Chad, but only if President Idriss Déby opens political space for the opposition beforehand.

The UN's release of a long awaited report on crimes committed in the Democratic Republic of Congo between 1993-2003 is not only an opportunity to re-examine the historical record of mass violence in DRC -- the scale and nature of which was often overlooked in the wake of the genocide in neighboring Rwanda -- but is also a chance to correct the terms of the deceptive and fragile peace some leaders wish to proclaim in the resource-rich Great Lakes region of Africa.

Es ist eine einmalige Chance, die sich dieser Tage bietet: Die Veröffentlichung eines lang erwarteten Berichts der Vereinten Nationen über Verbrechen in der Demokratischen Republik Kongo (DRK) ist die Gelegenheit für eine Wiederaufarbeitung der Geschichte der massiven Gewalt im Kongo zwischen 1993 und 2003.

As legislation requiring large U.S. companies to disclose the origins of the minerals they use is meant to come into force this year, Crisis Group sent a mission to North Kivu to assess the different strategies used to fight conflict minerals and their impact in the field.

The fight against entrenched armed groups in eastern Congo such as the ADF-Nalu needs to switch from a military to an intelligence-based approach.

As the Central African Republic (CAR) stares into an abyss of potentially appalling proportions, the international community must focus on the quickest, most decisive means of restoring security to its population.

The crisis that has been occurring in CAR is certainly the most dramatic in its history: more than 600 000 Central Africans are internally displaced or sought refuge in neighbouring countries; according to the United Nations, 1.7 million live in a constant situation of food insecurity and 878 000 need immediate medical assistance; Muslim communities are fleeing Bangui and the western region, subsistence economy no longer exists and the de facto partition of the country, caused by the sectarian violence, is gradually becoming a reality.

Cameroon’s apparent stability belies the variety of internal and external pressures threatening the country’s future. Without social and political change, a weakened Cameroon could become another flashpoint in the region.

Ahead of Chad’s presidential election on 10 April popular discontent is rising amid a major economic crisis, growing intra-religious tensions and deadly Boko Haram attacks. The regime that portrays itself as spearheading the fight against regional jihadism could see all sorts of violent actors gain influence at home if it pursues exclusionary politics and denies its people a viable social contract.

A 10-year study by a blue-ribbon panel of scientists concludes that high-stakes testing and other accountability measures have largely failed to translate to real improvements in student achievement.

This article, published ahead of print on 28 July 2008, has been withdrawn by the authors. Although moderate synergy between P2-RANTES and C peptides can be observed with high statistical significance in cell fusion assays, this synergy was not able to be verified in HIV viral assays. The authors regret the overstatement of synergy and will revise the paper for publication at a later date.

Objectives. The aim of this study was to assess the safety of early oral switch (EOS) prior to 14 days for low-risk Staphylococcus aureus bacteremia (LR-SAB), which is the primary treatment strategy employed at our institution. Usually recommended therapy is 14 days of intravenous (IV) antibiotics.

Methods. All patients with SAB at our hospital were identified between 1 January 2014 and 31 December 2018. Those meeting low-risk criteria (healthcare-associated, no evidence of deep infection or demonstrated involvement of prosthetic material, and no further positive blood cultures after 72-hours) were included in the study. The primary outcome was occurrence of a SAB-related complication within 90 days.

Results. There were 469 SAB episodes during the study period, 100 (21%) of whom met inclusion criteria. EOS was performed in 84 patients. In this group, line infection was the source in 79%, methicillin-susceptible S. aureus caused 95% of SABs and 74% of patients received IV flucloxacillin. The median duration of IV and oral antibiotics in the EOS group was 5 (IQR 4-6) and 10 days (IQR 9-14), respectively. Seventy-one percent of patients received flucloxacillin as their EOS agent. Overall, 86% of oral step-down therapy was with beta-lactams. One patient (1%) undergoing EOS had SAB relapse within 90 days. No deaths attributable to SAB occurred within 90 days.

Conclusions. In this low MRSA prevalence LR-SAB cohort, EOS was associated with a low incidence of SAB-related complications. This was achieved with oral beta-lactam therapy in most patients. Larger prospective studies are needed to confirm these findings.

QPX7728 is a new ultra-broad-spectrum inhibitor of serine and metallo beta-lactamases from a class of cyclic boronates that gave rise to vaborbactam. The spectrum and mechanism of beta-lactamase inhibition by QPX7728 were assessed using purified enzymes from all molecular classes. QPX7728 inhibits class A ESBLs (IC₅₀ range 1-3 nM) and carbapenemases such as KPC (IC₅₀ 2.9±0.4 nM) as well as class C P99 (IC₅₀ of 22±8 nM) with a potency that is comparable or higher than recently FDA approved BLIs avibactam, relebactam and vaborbactam. Unlike those other BLIs, QPX7728 is also a potent inhibitor of class D carbapenemases such as OXA-48 from Enterobacteriaceae and OXA enzymes from A. baumannii (OXA-23/24/58, IC₅₀ range 1-2 nM) as well as MBLs such as NDM-1 (IC₅₀ 55±25 nM), VIM-1 (IC₅₀ 14±4 nM) and IMP-1 (IC₅₀ 610±70 nM). Inhibition of serine enzymes by QPX7728 is associated with progressive inactivation with a high efficiency k₂/K ranging from of 6.3 x 10⁴ (for P99) to 9.9 x 10⁵ M^-1 s^-1 (for OXA-23). This inhibition is reversible with variable stability of the QPX7728-beta-lactamase complexes with target residence time ranging from minutes to several hours: 5-20 minutes for OXA carbapenemases from A. baumanii, ~50 minutes for OXA-48 and 2-3 hours for KPC and CTX-M-15. QPX7728 inhibited all tested serine enzymes at 1:1 molar ratio. Metallo-beta-lactamases NDM, VIM, and IMP were inhibited by a competitive mechanism with fast-on-fast-off kinetics, with K_is of 7.5±2.1 nM, 32±14 nM and 240±30 nM for VIM-1, NDM-1 and IMP-1, respectively. QPX7728 ultra-broad-spectrum of BLI inhibition combined with its high potency enables combinations with multiple different beta-lactam antibiotics.

β-lactam resistance in Staphylococcus aureus limits treatment options. Stp1 and Stk1, a serine-threonine phosphatase and kinase respectively, mediate serine-threonine kinase (STK) signaling. Loss of function point mutations in stp1 were detected among laboratory passaged, β-lactam resistant S. aureus strains lacking mecA and blaZ, the major determinants of β-lactam resistance in the bacteria. Loss of Stp1 function facilitates β-lactam resistance of the bacteria.

Carbapenem-resistant Gram-negative pathogens are a critical public health threat and there is an urgent need for new treatments. Carbapenemases (β-lactamases able to inactivate carbapenems) have been identified in both serine β-lactamase (SBL) and metallo β-lactamase (MBL) families. The recent introduction of SBL carbapenemase-inhibitors has provided alternative therapeutic options. Unfortunately, there are no approved inhibitors of MBL-mediated carbapenem-resistance and treatment options for infections caused by MBL-producing Gram-negatives are limited. Here, we present ZN148, a zinc-chelating MBL-inhibitor capable of restoring the bactericidal effect of meropenem and in vitro clinical susceptibility to carbapenems in >98% of a large international collection of MBL-producing clinical Enterobacterales strains (n=234). Moreover, ZN148 was able to potentiate the effect of meropenem against NDM-1-producing Klebsiella pneumoniae in a murine neutropenic peritonitis model. ZN148 showed no inhibition of the human zinc-containing enzyme glyoxylase II at 500 μM and no acute toxicity was observed in an in vivo mouse model with cumulative dosages up to 128 mg/kg. Biochemical analysis showed a time-dependent inhibition of MBLs by ZN148 and removal of zinc ions from the active site. Addition of exogenous zinc after ZN148 exposure only restored MBL activity by ~30%, suggesting an irreversible mechanism of inhibition. Mass-spectrometry and molecular modelling indicated potential oxidation of the active site Cys221 residue. Overall, these results demonstrate the therapeutic potential of a ZN148-carbapenem combination against MBL-producing Gram-negative pathogens and that ZN148 is a highly promising MBL inhibitor, capable of operating in a functional space not presently filled by any clinically approved compound.

Ibrexafungerp (formerly SCY-078) is a semisynthetic triterpenoid and potent (1->3)-β-D-glucan synthase inhibitor. We investigated the in vitro activity, pharmacokinetics, and in vivo efficacy of ibrexafungerp (SCY) alone and in combination with anti-mould triazole isavuconazole (ISA) against invasive pulmonary aspergillosis (IPA). The combination of ibrexafungerp and isavuconazole in in vitro studies resulted in an additive and synergistic interactions against Aspergillus spp. Plasma concentration-time curves of ibrexafungerp were compatible with linear dose proportional profile. In vivo efficacy was studied in a well established persistently neutropenic NZW rabbit model of experimental IPA. Treatment groups included untreated rabbits (UC) and rabbits receiving ibrexafungerp at 2.5(SCY2.5) and 7.5(SCY7.5) mg/kg/day, isavuconazole at 40(ISA40) mg/kg/day, or combinations of SCY2.5+ISA40 and SCY7.5+ISA40. The combination of SCY+ISA produced in vitro synergistic interaction. There was significant in vivo reduction of residual fungal burden, lung weights, and pulmonary infarct scores in SCY2.5+ISA40, SCY7.5+ISA40, and ISA40-treatment groups vs that of SCY2.5-treated, SCY7.5-treated and UC (p<0.01). Rabbits treated with SCY2.5+ISA40 and SCY7.5+ISA40 had prolonged survival in comparison to that of SCY2.5-, SCY7.5-, ISA40-treated or UC (p<0.05). Serum GMI and (1->3)-β-D-glucan levels significantly declined in animals treated with the combination of SCY7.5+ISA40 in comparison to those treated with SCY7.5 or ISA40 (p<0.05). Ibrexafungerp and isavuconazole combination demonstrated prolonged survival, decreased pulmonary injury, reduced residual fungal burden, lower GMI and (1->3)-β-D-glucan levels in comparison to those of single therapy for treatment of IPA. These findings provide an experimental foundation for clinical evaluation of the combination of ibrexafungerp and an anti-mould triazole for treatment of IPA.

Multi-drug resistance among Gram-negative bacteria is a major global public health threat. Metallo-β-lactamases (MBLs) target the most widely-used antibiotic class, the β-lactams, including the most recent-generation carbapenems. Interspecies spread renders these enzymes a serious clinical threat and there are no clinically-available inhibitors. We present crystal structures of IMP-13, a structurally-uncharacterized MBL from Gram-negative Pseudomonas aerugionasa found in clinical outbreaks globally, and characterize the binding using solution NMR-spectroscopy and molecular-dynamics simulations. Crystal structures of apo IMP-13 and bound to four clinically-relevant carbapenem antibiotics (doripenem, ertapenem, imipenem and meropenem) are presented. Active site plasticity and the active-site loop, where a tryptophan residue stabilizes the antibiotic core scaffold, are essential to the substrate-binding mechanism. The conserved carbapenem scaffold plays the most significant role in IMP-13 binding, explaining the broad substrate specificity. The observed plasticity and substrate-locking mechanism provide opportunities for rational drug design of novel metallo-β-lactamase inhibitors, essential in the fight against antibiotic resistance.

Telacebec (Q203) is a new anti-tubercular drug with extremely potent activity against Mycobacterium ulcerans. Here, we explored the treatment-shortening potential of Q203 alone or in combination with rifampin (RIF) in a mouse footpad infection model. The first study compared Q203 at 5 and 10 mg/kg doses alone and with rifampin. Q203 alone rendered most mouse footpads culture-negative in 2 weeks. Combining Q203 with rifampin resulted in relapse-free cure 24 weeks after completing 2 weeks of treatment, compared to a 25% relapse rate in mice receiving RIF+clarithromycin, the current standard of care, for 4 weeks.

The second study explored the dose-ranging activity of Q203 alone and with RIF, including the extended activity of Q203 after treatment discontinuation. The bactericidal activity of Q203 persisted for ≥ 4 weeks beyond the last dose. All mice receiving just 1 week of Q203 at 2-10 mg/kg were culture-negative 4 weeks after stopping treatment. Mice receiving 2 weeks of Q203 at 0.5, 2 and 10 mg/kg were culture-negative 4 weeks after treatment. RIF did not increase the efficacy of Q203. A pharmacokinetics sub-study revealed that Q203 doses of 2-10 mg/kg in mice produce plasma concentrations similar to those produced by 100-300 mg doses in humans, with no adverse effect of RIF on Q203 concentrations.

These results indicate the extraordinary potential of Q203 to reduce the duration of treatment necessary for cure to ≤ 1 week (or 5 doses of 2-10 mg/kg) in our mouse footpad infection model and warrant further evaluation of Q203 in clinical trials.

QPX7728 is an ultra-broad-spectrum boronic acid beta-lactamase inhibitor with potent inhibition of key serine and metallo beta-lactamases observed in biochemical assays. Microbiological studies using characterized strains were used to provide a comprehensive characterization of the spectrum of beta-lactamase inhibition by QPX7728. The MIC of multiple IV only (ceftazidime, piperacillin, cefepime, ceftolozane and meropenem) and orally bioavailable (ceftibuten, cefpodoxime, tebipenem) antibiotics alone and in combination with QPX7728 (4 μg/ml), as well as comparator agents, were determined against the panels of laboratory strains of P. aeruginosa and K. pneumoniae expressing over 55 diverse serine and metallo beta-lactamases. QPX7728 significantly enhanced the potency of antibiotics against the strains expressing Class A extended spectrum beta-lactamases (CTX-M, SHV, TEM, VEB, PER) and carbapenemases (KPC, SME, NMC-A, BKC-1), consistent with beta-lactamase inhibition demonstrated in biochemical assays. It also inhibits both plasmidic (CMY, FOX, MIR, DHA) and chromosomally encoded (P99, PDC, ADC) Class C beta-lactamases and Class D enzymes including carbapenemases such as OXA-48 from Enterobacteriaceae and OXA enzymes from Acinetobacter baumannii (OXA-23/24/72/58). QPX7728 is also a potent inhibitor of many class B metallo beta-lactamases (NDM, VIM, CcrA1, IMP, GIM but not SPM or L1). Addition of QPX7728 (4 μg/ml) reduced the MICs in a majority of strains to the level observed for the vector alone control, indicative of complete beta-lactamase inhibition. The ultra-broad-spectrum beta-lactamase inhibition profile makes QPX7728 a viable candidate for further development.

The Cpx stress response is widespread among Enterobacteriaceae. We have previously reported a mutation in cpxA in a multidrug resistant strain of Klebsiella aerogenes isolated from a patient treated with imipenem. This mutation yields to a single amino acid substitution (Y144N) located in the periplasmic sensor domain of CpxA. In this work, we sought to characterize this mutation in Escherichia coli by using genetic and biochemical approaches. Here, we show that cpxA^Y144N is an activated allele that confers resistance to β-lactams and aminoglycosides in a CpxR-dependent manner, by regulating the expression of the OmpF porin and the AcrD efflux pump, respectively. We also demonstrate the intimate interconnection between Cpx system and peptidoglycan integrity on the expression of an exogenous AmpC β-lactamase by using imipenem as a cell wall active antibiotic or inactivation of penicillin-binding proteins. Moreover, our data indicate that the Y144N substitution abrogates the interaction between CpxA and CpxP and increase phosphotransfer activity on CpxR. Because the addition of a strong AmpC inducer such as imipenem is known to causes abnormal accumulation of muropeptides (disaccharide-pentapeptide, N-acetylglucosamyl-1,6-anhydro-N-acetylmuramyl-l-alanyl-d-glutamy-meso-diaminopimelic-acid-d-alanyl-d-alanine) in the periplasmic space, we propose these molecules activate the Cpx system by displacing CpxP from the sensor domain of CpxA. Altogether, these data could explain why large perturbations to peptidoglycan caused by imipenem lead to mutational activation of the Cpx system and bacterial adaptation through multidrug resistance. These results also validate the Cpx system, in particular the interaction between CpxA and CpxP, as a promising therapeutic target.

QPX7728 is an ultra-broad-spectrum boronic acid beta-lactamase inhibitor that demonstrates inhibition of key serine and metallo beta-lactamases at a nano molar range in biochemical assays with purified enzymes. The broad-spectrum inhibitory activity of QPX7728 observed in biochemical experiments translates into enhancement of the potency of many beta-lactams against strains of target pathogens producing beta-lactamases. The impact of bacterial efflux and permeability on inhibitory potency were determined using isogenic panels of KPC-3 producing isogenic strains of K. pneumoniae and P. aeruginosa and OXA-23-producing strains of A. baumannii with various combinations of efflux and porin mutations. QPX7728 was minimally affected by multi-drug resistance efflux pumps in either Enterobacteriaceae, or in non-fermenters such as P. aeruginosa or A. baumannii. In P. aeruginosa, the potency of QPX7728 was further enhanced when the outer membrane is permeabilized. The potency of QPX7728 in P. aeruginosa is not affected by inactivation of the carbapenem porin OprD. While changes in OmpK36 (but not OmpK35) reduced the potency of QPX7728 (8-16-fold), QPX7728 (4 μg/ml) nevertheless completely reversed KPC-mediated meropenem resistance in strains with porin mutations, consistent with a lesser effect of these mutations on the potency of QPX7728 compared to other agents. The ultra-broad-spectrum beta-lactamase inhibition profile combined with enhancement of the activity of multiple beta-lactam antibiotics with varying sensitivity to the intrinsic resistance mechanisms of efflux and permeability indicate QPX7728 is a useful inhibitor for use with multiple beta-lactam antibiotics.

There is an urgent need for new, potent anti-tuberculosis (TB) drugs with novel mechanisms of action that can be included in new regimens to shorten the treatment period for TB. After screening a library of carbostyrils, we optimized 3, 4-dihydrocarbostyril derivatives and identified OPC-167832 as having potent anti-tuberculosis activity. The minimum inhibitory concentrations of the compound for Mycobacterium tuberculosis ranged from 0.00024 to 0.002 μg/mL. It had bactericidal activity against both growing and intracellular bacilli, and the frequency of spontaneous resistance for Mycobacterium tuberculosis H37Rv was less than 1.91 x 10^-7. It did not show antagonistic effects with other anti-TB agents in an in vitro checkerboard assay. Whole genome and targeted sequencing of resistant isolates to OPC-167832 identified the decaprenylphosphoryl-β-D-ribose 2'-oxidase (DprE1), an essential enzyme for cell wall biosynthesis, as the target of this compound, and further studies demonstrated inhibition of the DprE1 enzymatic activity by OPC-167832. In a mouse model of chronic TB, OPC-167832 showed potent bactericidal activities starting at a dose of 0.625 mg/kg. Further, it exhibited significant combination effects in 2-drug combinations with delamanid, bedaquiline, or levofloxacin. Finally, 3-4 drug regimens comprised of delamanid and OPC-167832 as the core along with bedaquiline, moxifloxacin, or linezolid showed superior efficacy in reducing bacterial burden and preventing relapse compared to the standard treatment regimen. In summary, these results suggest that OPC-167832 is a novel and potent anti-TB agent and regimens containing OPC-167832 and new or repurposed anti-TB drugs may have the potential to shorten the duration of treatment for TB.

The biologic Griffithsin (GRFT) has recently emerged as a candidate to safely prevent sexually transmitted infections (STIs) including human immunodeficiency virus (HIV-1) and herpes simplex virus 2 (HSV-2). However, to date, there are few delivery platforms that are available to effectively deliver biologics to the female reproductive tract (FRT). The goal of this work was to evaluate rapid-release polyethylene oxide (PEO), polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) fibers, that incorporate GRFT, in in vitro (HIV-1 and HSV-2) and in vivo (HSV-2) infection models. GRFT loading was determined via ELISA, and the bioactivity of GRFT fibers was assessed using in vitro HIV-1 pseudovirus and HSV-2 plaque assays. Afterwards, the efficacy of GRFT fibers was assessed in a murine model of lethal HSV-2 infection. Finally, murine reproductive tracts and vaginal lavages were evaluated for histology and cytokine expression, 24 and 72 hr after fiber administration, to determine safety. All rapid-release formulations achieved high levels of GRFT incorporation and were completely efficacious against in vitro HIV-1 and HSV-2 infections. Importantly, all rapid-release GRFT fibers provided potent protection in a murine model of HSV-2 infection. Moreover, histology and cytokine levels, evaluated from collected murine reproductive tissues and vaginal lavages treated with blank fibers, showed no increased cytokine production or histological aberrations, demonstrating the preliminary safety of rapid-release GRFT fibers in vaginal tissue.

Mycobacterium abscessus lung infections remain difficult to treat. Recent studies have recognized the power of new combinations of antibiotics such as bedaquiline and imipenem although in vitro data have questioned this combination. We report that the efficacy of the bedaquiline plus imipenem treatment relies essentially on the activity of bedaquiline in a C3HeB/FeJ mice model of infection with a rough variant of M. abscessus. The addition of imipenem contributed at clearing the infection in the spleen.

Klebsiella pneumoniae that produce extended spectrum beta lactamases (ESBLs) are a persistent public health threat. There are relatively few therapeutic options and there is undue reliance on carbapenems. Alternative therapeutic options are urgently required. A combination of cefepime and the novel beta lactamase inhibitor enmetazobactam is being developed for treatment of serious infections caused by ESBL-producing organisms. The pharmacokinetics-pharmacodynamics (PK-PD) of cefepime-enmetazobactam against ESBL-producing K. pneumoniae was studied in a neutropenic murine pneumonia model. Dose ranging studies were performed. Dose fractionation studies were performed to define the relevant PD index for the inhibitor. The partitioning of cefepime and enmetazobactam into the lung was determined by comparing area under the concentration time curve (AUC) in plasma and epithelial lining fluid. The magnitude of drug exposure for cefepime-enmetazobactam required for logarithmic killing in the lung was defined using 3 ESBL-producing strains. Cefepime 100 mg/kg q8h i.v. had minimal antimicrobial effect. When this background regimen of cefepime was combined with enmetazobactam half-maximal effect was induced with enmetazobactam 4.71 mg/kg q8h i.v. The dose fractionation study suggest both fT>threshold and fAUC:MIC are potentially relevant PD indices. The AUC_ELF:AUC_plasma for cefepime and enmetazobactam was 73.4% and 61.5%, respectively. A ≥2-log kill in the lung was achieved with a plasma and ELF cefepime fT>MIC of ≥20% and enmetazobactam fT>2 mg/L of ≥20% of the dosing interval. These data and analyses provide the underpinning evidence for the combined use of cefepime and enmetazobactam for nosocomial pneumonia.

The human diseases caused by the fungal pathogens Cryptococcus neoformans and C. gattii are associated with high indices of mortality, and toxic and/or cost-prohibitive therapeutic protocols. The need for affordable antifungals to combat cryptococcal disease is unquestionable. Previous studies suggested benzimidazoles as promising anti-cryptococcal agents combining low cost and high antifungal efficacy, but their therapeutic potential has not been demonstrated so far. In this study, we investigated the antifungal potential of fenbendazole, the most effective anti-cryptococcal benzimidazole. Fenbendazole was inhibitory against 17 different isolates of C. neoformans and C. gattii at a low concentration. The mechanism of anti-cryptococcal activity of fenbendazole involved microtubule disorganization, as previously described for human parasites. In combination with fenbendazole, the concentrations of the standard antifungal amphotericin B required to control cryptococcal growth were lower than those required when this antifungal was used alone. Fenbendazole was not toxic to mammalian cells. During macrophage infection, the anti-cryptococcal effects of fenbendazole included inhibition of intracellular proliferation rates and reduced phagocytic escape through vomocytosis. Fenbendazole deeply affected the cryptococcal capsule. In a mice model of cryptococcosis, the efficacy of fenbendazole to control animal mortality was similar to that observed for amphotericin B. These results indicate that fenbendazole is a promising candidate for the future development of an efficient and affordable therapeutic tool to combat cryptococcosis.

Chromosomal and plasmid-borne AmpC cephalosporinases are a major resistance mechanism to β-lactams in Enterobacteriaceae and Pseudomonas aeruginosa. The new β-lactamase inhibitor avibactam effectively inhibits class C enzymes and can fully restore ceftazidime susceptibility. The conserved amino acid residue Asn³⁴⁶ of AmpC cephalosporinases directly interacts with the avibactam sulfonate. Disruption of this interaction caused by the N³⁴⁶Y amino acid substitution in Citrobacter freundii AmpC was previously shown to confer resistance to the ceftazidime-avibactam combination (CAZ-AVI). The aim of this study was to phenotypically and biochemically characterize the consequences of the N³⁴⁶Y substitution in various AmpC backgrounds. Introduction of N³⁴⁶Y into Enterobacter cloacae AmpC (AmpC_cloacae), plasmid-mediated DHA-1, and P. aeruginosa PDC-5, led to 270-, 12,000-, and 79-fold decreases in the inhibitory efficacy (k₂/K_i) of avibactam, respectively. The kinetic parameters of AmpC_cloacaeand DHA-1 for ceftazidime hydrolysis were moderately affected by the substitution. Accordingly, AmpC_cloacaeand DHA-1 harboring N³⁴⁶Y conferred CAZ-AVI resistance (MIC of ceftazidime of 16 µg/ml in the presence of 4 µg/ml of avibactam). In contrast, production of PDC-5 N³⁴⁶Y was associated with a lower MIC (4 µg/ml) since this β-lactamase retained a higher inactivation efficacy by avibactam in comparison to AmpC_cloacaeN³⁴⁶Y. For FOX-3, the I³⁴⁶Y substitution did not reduce the inactivation efficacy of avibactam and the substitution was highly deleterious for β-lactam hydrolysis, including ceftazidime, preventing CAZ-AVI resistance. Since AmpC_cloacaeand DHA-1 display substantial sequence diversity, our results suggest that loss of hydrogen interaction between Asn³⁴⁶ and avibactam could be a common mechanism of acquisition of CAZ-AVI resistance.

Durlobactam (DUR, also known as ETX2514) is a novel β-lactamase inhibitor with broad activity against Ambler class A, C, and D β-lactamases. Addition of DUR to sulbactam (SUL) in vitro restores SUL activity against clinical isolates of Acinetobacter baumannii. The safety and pharmacokinetics (PK) of DUR alone and with SUL and/or imipenem/cilastatin (IMI/CIL) were evaluated in healthy subjects. This was a randomized, placebo-controlled study. In Part A, subjects including an elderly cohort (DUR 1 g) received single ascending doses of DUR 0.25-8 g. In Part B, multiple ascending dose of DUR 0.25-2 g were administered every 6 hours (q6h) for 29 doses. In Parts C and D, the drug-drug interaction (DDI) potential, including safety, of DUR (1 g) with SUL (1 g) and/or IMI/CIL (0.5/0.5 g) was investigated after single and multiple doses. Plasma and urine concentrations of DUR, SUL, and IMI/CIL were determined. Among 124 subjects, DUR was generally safe and well tolerated either alone or in combination with SUL and/or IMI/CIL. After single and multiple doses, DUR demonstrated linear dose proportional exposure across the studied dose ranges. Renal excretion was a predominant clearance mechanism. No drug:drug interaction potential was identified between DUR and SUL and/or IMI/CIL. SUL-DUR, 1 g (of each component) administered q6h with a 3 hour IV infusion, is under development for the treatment of serious infections due to A. baumannii.

The SHV β-lactamases (BLs) have undergone strong allele diversification that changed their substrate specificities. Based on 147 NCBI entries for SHV alleles, in silico mathematical models predicted five positions as relevant for the β-lactamase inhibitor (BLI) resistant (2br) phenotype, 12 as relevant for the extended-spectrum BL (ESBL) (2be) phenotype, and two positions were related to solely the narrow spectrum (2b) phenotype. These positions and additional 6 positions described in other studies (including one promoter mutation), were systematically substituted and investigated for their substrate specificities in a BL-free E. coli background, representing, to our knowledge, the most comprehensive substrate and substitution analysis for SHV alleles to date. An in vitro analysis confirmed the essentiality of the positions 238 and 179 for the 2be phenotype and 69 for the 2br phenotype. The substitutions E240K and E240R, which do not occur alone in known 2br SHV variants, led to a 2br phenotype, indicating a latent BLI-resistance potential of these substitutions. The substitutions M129V, A234G, S271I and R292Q conferred latent resistance to cefotaxime. In addition, 7 positions that were found to be not always associated with the ESBL phenotype resulted in increased resistance to ceftaroline. We also observed that coupling of a strong promoter (IS26) to a A146V mutant with the 2b phenotype resulted in a highly increased resistance to BLIs, cefepime and ceftaroline but not to 3^rd generation cephalosporins, indicating that SHV enzymes represent an underestimated risk for empirical therapies that use piperacillin/tazobactam or cefepime to treat different infectious diseases caused by gram-negatives.

A total of 2,283 Salmonella spp. isolates were recovered from 18,334 samples including patients with diarrhea, food of animal origin and pets across 5 provinces of China. The highest prevalence of Salmonella spp. was detected in chicken meats (39.3%, 486/1,237). Fifteen serogroups and 66 serovars were identified, with Typhimurium and Enteritidis being the most dominant. Most (85.5%, 1,952/2,283) isolates exhibited resistant to ≥ 1 antimicrobial and 56.4% were multi-drug resistant (MDR). A total of 222 isolates harbored extended-spectrum β-lactamases (ESBLs), 200 of which were CTX-M-type that were mostly detected from chicken meat and turtle fecal. Overall, eight bla_CTX-M genes were identified, with bla_CTX-M-65, bla_CTX-M-123, bla_CTX-M-14, bla_CTX-M-79, and bla_CTX-M-130 being the most prevalent. Totally, 166 of the 222 ESBL-producing isolates had amino acid substitutions in GyrA (S83Y, S83F, D87G, D87N, and D87Y) and ParC (and S80I), whilst the PMQR-encoding genes oqxA/B, qepA, and qnrB/S were detected in almost all isolates. Of the fifteen sequence types (STs) identified in the 222 ESBLs, ST17, ST11, ST34, and ST26 ranked among the top 5 in the number of isolates. Our study revealed considerable serovars diversity, high prevalence of co-occurrence of MDR determinants, including CTX-M-type ESBLs, QRDRs mutations and PMQR genes. This is the first report of CTX-M-130 Salmonella spp. from patients with diarrhea and QRDRs mutations from turtle fecal samples. Our study emphasizes the importance of actions, both in the health care settings and in the veterinary medicine sector, to control the dissemination of MDR, especially the CTX-M Salmonella spp. isolates.

Methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections (BSI) are associated with substantial morbidity and mortality. Monotherapy with first-line antimicrobials such as vancomycin (VAN; glycopeptide) and daptomycin (DAP; lipopeptide) are inadequate in some cases due to reduced antibiotic susceptibilities or therapeutic failure. In recent years, β-lactam antibiotics have emerged as a potential option for combination therapy with VAN/DAP that may meet an unmet therapeutic need for MRSA BSI. Ceftaroline (CPT), the only commercially available β-lactam in the United States with intrinsic in vitro activity against MRSA, has been increasingly studied in the setting of VAN and DAP failures. Novel combinations of first-line agents (VAN and DAP) with β-lactams have been the subject of many recent investigations due to in vitro findings such as the "see-saw effect", where β-lactam susceptibility may be improved in the presence of decreased glycopeptide and lipopeptide susceptibility. The combination of CPT and DAP, in particular, has become the focus of many scientific evaluations, due to intrinsic anti-MRSA activities and potent in vitro synergistic activity against various MRSA strains. This article reviews the available literature describing these innovative therapeutic approaches for MRSA BSI, focusing on preclinical and clinical studies, and evaluates the potential benefits and limitations of each strategy.

Globally, mutations in the katG gene account for the majority of isoniazid-resistant strains of Mycobacterium tuberculosis. Buyankhishig et al analyzed a limited number of Mycobacterium tuberculosis strains in Mongolia and found that isoniazid resistance was mainly attributable to inhA mutations. The GenoType® MTBDRplus assay was performed for isolates collected in the First National Tuberculosis Prevalence Survey and the Third Anti-Tuberculosis Drug Resistance Survey to investigate genetic mutations associated with isoniazid resistance in Mycobacterium tuberculosis in Mongolia. Of the 409 isoniazid-resistant isolates detected by the GenoType® MTBDRplus assay, 127 (31.1%) were resistant to rifampicin, 294 (71.9%) had inhA mutations without katG mutations, 113 (27.6%) had katG mutations without inhA mutations, and two (0.5%) strains had mutations in both the inhA and katG genes. Of the 115 strains with any katG mutation, 114 (99.1%) had mutations in codon 315 (S315T). Of the 296 trains with any inhA mutation, 290 (98.0%) had a C–15T mutation. The proportion of isoniazid-resistant strains with katG mutations was 25.3% among new cases and 36.2% among retreatment cases (p=0.03), as well as 17.0% among rifampicin-susceptible strains and 52.8% among rifampicin-resistant strains (p<0.01). Rifampicin resistance was significantly associated with the katG mutation (adjusted odds ratio 5.36, 95% CI 3.3–8.67, p<0.001). Mutations in inhA predominated in isoniazid-resistant tuberculosis in Mongolia. However, the proportion of katG mutations in isolates from previously treated cases was higher than that among new cases, and that in cases with rifampicin resistance was higher than that in cases without rifampicin resistance.