Combination antibiotic therapy for community-acquired pneumonia

In Vitro antibiotic combinations of Colistin, Meropenem, Amikacin, and Amoxicillin/clavulanate against multidrug-resistant Klebsiella pneumonia isolated from patients with ventilator-associated pneumonia

BACKGROUND

Hospital infections such as ventilator-associated pneumonia (VAP) due to multidrug-resistant Klebsiella pneumoniae (MDR-KP) strains have increased worldwide. In addition, biofilm production by these resistant isolates has confronted clinicians with higher treatment failure and infection recurrence. Given the paucity of new agents and limited data on combination therapy for MDR-KPs, the present study sought to evaluate the in vitro activity of several antibiotic combinations against planktonic and biofilm MDR-KPs isolated from patients with VAP.

RESULTS

All 10 carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates demonstrated multidrug resistance against the tested antibiotics. At planktonic mode, combinations of colistin-meropenem and amoxicillin/clavulanate in combination with meropenem, colistin, or amikacin showed synergism against 60-70% isolates. On the other hand, in the biofilm state, colistin-based combinations exhibited synergism against 50-70% isolates and the most effective combination was colistin-amikacin with 70% synergy.

CONCLUSIONS

The results revealed that combinations of amoxicillin/clavulanate with colistin, meropenem, or amikacin in the planktonic mode and colistin with amoxicillin/clavulanate, meropenem, or amikacin in the biofilm mode could effectively inhibit CRKP isolates, and thus could be further explored for the treatment of CRKPs.

Coping with the ESKAPE pathogens: Evolving strategies, challenges and future prospects

Globally, the ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) are the major cause of nosocomial infections. These pathogens are multidrug resistant, and their negative impacts have brought serious health challenges and economic burden on many countries worldwide. Thus, this narrative review exploits different emerging alternative therapeutic strategies including combination antibiotics, antimicrobial peptides ((AMPs), bacteriophage and photodynamic therapies used in the treatment of the ESKAPE pathogens, their merits, limitations, and future prospects. Our findings indicate that ESKAPE pathogens exhibit resistance to drug using different mechanisms including drug inactivation by irreversible enzyme cleavage, drug-binding site alteration, diminution in permeability of drug or drug efflux increment to reduce accumulation of drug as well as biofilms production. However, the scientific community has shown significant interest in using these novel strategies with numerous benefits although they have some limitations including but not limited to instability and toxicity of the therapeutic agents, or the host developing immune response against the therapeutic agents. Thus, comprehension of resistance mechanisms of these pathogens is necessary to further develop or modify these approaches in order to overcome these health challenges including the barriers of bacterial resistance.

Appropriateness of antimicrobial selection for treatment of pneumonia in selected public hospitals of Eastern Ethiopia: A cross-sectional study

Objective

Inappropriate antimicrobial use leads to drug resistance and poor clinical outcomes. Considering the lack of data regarding the drug use patterns in the treatment of pneumonia in selected study areas, the authors felt compelled to assess the appropriateness of antimicrobial usage in the treatment of pneumonia at Hiwot Fana Specialized Comprehensive University Hospital and Jugal Hospital from May 1 to 31, 2021.

Methods

A cross-sectional retrospective study was conducted using the medical cards of 693 admitted patients with pneumonia. The collected data were analyzed using SPSS version 26. Bivariable and multivariable logistic regression analyses were used to identify the factors associated with an initial inappropriate antibiotic use. A p value of 0.05 was used to determine the statistical significance of the association using an adjusted odds ratio with 95% confidence interval.

Results

Of the total participants, 116 (16.74%, 95% confidence interval: 14.1-19.6) of them received an initial inappropriate antimicrobial regimen. Ceftriaxone plus azithromycin was the most prescribed antimicrobial agent. Patients who were younger than 5 years (adjusted odds ratio = 1.71; 95% confidence interval: 1.00-2.94), between 6 and 14 years (adjusted odds ratio = 3.14; 95% confidence interval: 1.64-6.00), and older than 65 years (adjusted odds ratio = 2.97; 95% confidence interval: 1.07-2.66), with comorbid conditions (adjusted odds ratio = 1.74; 95% confidence interval: 1.10-2.72) and prescribed by medical interns (adjusted odds ratio = 1.80; 95% confidence interval: 1.14-2.84) were associated with an initial inappropriate antimicrobial use.

Conclusion

Around one out of every six patients had received initial inappropriate treatments. Adherence to the recommendation of guidelines and attention to extreme-aged groups and comorbidity may improve antimicrobial use.

The Potential of Antibiotics and Nanomaterial Combinations as Therapeutic Strategies in the Management of Multidrug-Resistant Infections: A Review

Antibiotic resistance has become a major public health concern around the world. This is exacerbated by the non-discovery of novel drugs, the development of resistance mechanisms in most of the clinical isolates of bacteria, as well as recurring infections, hindering disease treatment efficacy. In vitro data has shown that antibiotic combinations can be effective when microorganisms are resistant to individual drugs. Recently, advances in the direction of combination therapy for the treatment of multidrug-resistant (MDR) bacterial infections have embraced antibiotic combinations and the use of nanoparticles conjugated with antibiotics. Nanoparticles (NPs) can penetrate the cellular membrane of disease-causing organisms and obstruct essential molecular pathways, showing unique antibacterial mechanisms. Combined with the optimal drugs, NPs have established synergy and may assist in regulating the general threat of emergent bacterial resistance. This review comprises a general overview of antibiotic combinations strategies for the treatment of microbial infections. The potential of antibiotic combinations with NPs as new entrants in the antimicrobial therapy domain is discussed.

Comparison of prognostic factors between bacteraemic and non-bacteraemic critically ill immunocompetent patients in community-acquired severe pneumococcal pneumonia: a STREPTOGENE sub-study

Background

The presence of bacteraemia in pneumococcal pneumonia in critically ill patients does not appear to be a strong independent prognostic factor in the existing literature. However, there may be a specific pattern of factors associated with mortality for ICU patients with bacteraemic pneumococcal community-acquired pneumonia (CAP). We aimed to compare the factors associated with mortality, according to the presence of bacteraemia or not on admission, for patients hospitalised in intensive care for severe pneumococcal CAP.

Methods

This was a post hoc analysis of data from the prospective, observational, multicentre STREPTOGENE study in immunocompetent Caucasian adults admitted to intensive care in France between 2008 and 2012 for pneumococcal CAP. Patients were divided into two groups based on initial blood culture (positive vs. negative) for Streptococcus pneumoniae. The primary outcome was hospital mortality, which was compared between the two groups using odds ratios according to predefined variables to search for a prognostic interaction present in bacterial patients but not non-bacteraemic patients. Potential differences in the distribution of serotypes between the two groups were assessed. The prognostic consequences of the presence or not of initial bi-antibiotic therapy were assessed, specifically in bacteraemic patients.

Results

Among 614 included patients, 274 had a blood culture positive for S. pneumoniae at admission and 340 did not. The baseline difference between the groups was more frequent leukopaenia (26% vs. 14%, p = 0.0002) and less frequent pre-hospital antibiotic therapy (10% vs. 16.3%, p = 0.024) for the bacteraemic patients. Hospital mortality was not significantly different between the two groups (p = 0.11). We did not observe any prognostic factors specific to the bacteraemic patient population, as the statistical comparison of the odds ratios, as an indication of the association between the predefined prognostic parameters and mortality, showed them to be similar for the two groups. Bacteraemic patients more often had invasive serotypes but less often serotypes associated with high case fatality rates (p = 0.003). The antibiotic regimens were similar for the two groups. There was no difference in mortality for patients in either group given a beta-lactam alone vs. a beta-lactam combined with a macrolide or fluoroquinolone.

Conclusion

Bacteraemia had no influence on the mortality of immunocompetent Caucasian adults admitted to intensive care for severe pneumococcal CAP, regardless of the profile of the associated prognostic factors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00936-z.

C-Reactive Protein-Based Strategy to Reduce Antibiotic Dosing for the Treatment of Pneumococcal Infection

C-reactive protein (CRP) is a component of innate immunity. The concentration of CRP in serum increases in microbial infections including Streptococcus pneumoniae infection. Employing a mouse model of pneumococcal infection, it has been shown that passively administered human wild-type CRP protects mice against infection, provided that CRP is injected into mice within two hours of administering pneumococci. Engineered CRP (E-CRP) molecules have been reported recently; unlike wild-type CRP, passively administered E-CRP protected mice against infection even when E-CRP was injected into mice after twelve hours of administering pneumococci. The current study was aimed at comparing the protective capacity of E-CRP with that of an antibiotic clarithromycin. We established a mouse model of pneumococcal infection in which both E-CRP and clarithromycin, when used alone, provided minimal but equal protection against infection. In this model, the combination of E-CRP and clarithromycin drastically reduced bacteremia and increased survival of mice when compared to the protective effects of either E-CRP or clarithromycin alone. E-CRP was more effective in reducing bacteremia in mice treated with clarithromycin than in untreated mice. Also, there was 90% reduction in antibiotic dosing by including E-CRP in the antibiotic-treatment for maximal protection of infected mice. These findings provide an example of cooperation between the innate immune system and molecules that prevent multiplication of bacteria, and that should be exploited to develop novel combination therapies for infections against multidrug-resistant pneumococci. The reduction in antibiotic dosing by including E-CRP in the combination therapy might also resolve the problem of developing antibiotic resistance.

Exploring metabolic adaptation of Streptococcus pneumoniae to antibiotics

The Gram-positive bacterium Streptococcus pneumoniae is one of the common causes of community acquired pneumonia, meningitis, and otitis media. Analyzing the metabolic adaptation toward environmental stress conditions improves our understanding of its pathophysiology and its dependency on host-derived nutrients. In this study, extra- and intracellular metabolic profiles were evaluated to investigate the impact of antimicrobial compounds targeting different pathways of the metabolome of S. pneumoniae TIGR4Δcps. For the metabolomics approach, we analyzed the complex variety of metabolites by using ¹H NMR, HPLC-MS, and GC–MS as different analytical techniques. Through this combination, we detected nearly 120 metabolites. For each antimicrobial compound, individual metabolic effects were detected that often comprised global biosynthetic pathways. Cefotaxime altered amino acids metabolism and carbon metabolism. The purine and pyrimidine metabolic pathways were mostly affected by moxifloxacin treatment. The combination of cefotaxime and azithromycin intensified the stress response compared with the use of the single antibiotic. However, we observed that three cell wall metabolites were altered only by treatment with the combination of the two antibiotics. Only moxifloxacin stress-induced alternation in CDP-ribitol concentration. Teixobactin-Arg10 resulted in global changes of pneumococcal metabolism. To meet the growing requirements for new antibiotics, our metabolomics approach has shown to be a promising complement to other OMICs investigations allowing insights into the mode of action of novel antimicrobial compounds.

Recovery rates of combination antibiotic therapy using in vitro microdialysis simulating in vivo conditions

Microdialysis is a technique used to measure the unbound antibiotic concentration in the interstitial spaces, the target site of action. In vitro recovery studies are essential to calibrating the microdialysis system for in vivo studies. The effect of a combination of antibiotics on recovery into microdialysate requires investigation. In vitro microdialysis recovery studies were conducted on a combination of vancomycin and tobramycin, in a simulated in vivo model. Comparison was made between recoveries for three different concentrations and three different perfusate flow rates. The overall relative recovery for vancomycin was lower than that of tobramycin. For tobramycin, a concentration of 20μg/mL and flow rate of 1.0μL/min had the best recovery. A concentration of 5.0μg/mL and flow rate of 1.0μL/min yielded maximal recovery for vancomycin. Large molecular size and higher protein binding resulted in lower relative recoveries for vancomycin. Perfusate flow rates and drug concentrations affected the relative recovery when a combination of vancomycin and tobramycin was tested. Low perfusate flow rates were associated with higher recovery rates. For combination antibiotic measurement which includes agents that are highly protein bound, in vitro studies performed prior to in vivo studies may ensure the reliable measurement of unbound concentrations.

Mechanisms of action and in vivo antibacterial efficacy assessment of five novel hybrid peptides derived from Indolicidin and Ranalexin against Streptococcus pneumoniae

BACKGROUND

Antimicrobial peptides (AMPs) are of great potential as novel antibiotics for the treatment of broad spectrum of pathogenic microorganisms including resistant bacteria. In this study, the mechanisms of action and the therapeutic efficacy of the hybrid peptides were examined.

METHODS

TEM, SEM and ATP efflux assay were used to evaluate the effect of hybrid peptides on the integrity of the pneumococcal cell wall/membrane. DNA retardation assay was assessed to measure the impact of hybrid peptides on the migration of genomic DNA through the agarose gel. In vitro synergistic effect was checked using the chequerboard assay. ICR male mice were used to evaluate the in vivo toxicity and antibacterial activity of the hybrid peptides in a standalone form and in combination with ceftriaxone.

RESULTS

The results obtained from TEM and SEM indicated that the hybrid peptides caused significant morphological alterations in Streptococcus pneumoniae and disrupting the integrity of the cell wall/membrane. The rapid release of ATP from pneumococcal cells after one hour of incubation proposing that the antibacterial action for the hybrid peptides is based on membrane permeabilization and damage. The DNA retardation assay revealed that at 62.5 µg/ml all the hybrid peptides were capable of binding and preventing the pneumococcal genomic DNA from migrating through the agarose gel. In vitro synergy was observed when pneumococcal cells treated with combinations of hybrid peptides with each other and with conventional drugs erythromycin and ceftriaxone. The in vivo therapeutic efficacy results revealed that the hybrid peptide RN7-IN8 at 20 mg/kg could improve the survival rate of pneumococcal bacteremia infected mice, as 50% of the infected mice survived up to seven days post-infection. In vivo antibacterial efficacy of the hybrid peptide RN7-IN8 was signficantly improved when combined with the standard antibiotic ceftriaxone at (20 mg/kg + 20 mg/kg) as 100% of the infected mice survived up to seven days post-infection.

DISCUSSION

Our results suggest that attacking and breaching the cell wall/membrane is most probably the principal mechanism for the hybrid peptides. In addition, the hybrid peptides could possess another mechanism of action by inhibiting intracellular functions such as DNA synthesis. AMPs could play a great role in combating antibiotic resistance as they can reduce the therapeutic concentrations of standard drugs.

Efficacy of β-Lactam-plus-Macrolide Combination Therapy in a Mouse Model of Lethal Pneumococcal Pneumonia

Community-acquired pneumonia is a common disease with considerable morbidity and mortality, for which Streptococcus pneumoniae is accepted as a leading cause. Although β-lactam-plus-macrolide combination therapy for this disease is recommended in several guidelines, the clinical efficacy of this strategy against pneumococcal pneumonia remains controversial. In this study, we examined the effects of β-lactam-plus-macrolide combination therapy on lethal mouse pneumococcal pneumonia and explored the mechanisms of action in vitro and in vivo We investigated survival, lung bacterial burden, and cellular host responses in bronchoalveolar lavage fluids obtained from mice infected with pneumonia and treated with ceftriaxone, azithromycin, or both in combination. Although in vitro synergy was not observed, significant survival benefits were demonstrated with combination treatment. Lung neutrophil influx was significantly lower in the ceftriaxone-plus-azithromycin-treated group than in the ceftriaxone-treated group, whereas no differences in the lung bacterial burden were observed on day 3 between the ceftriaxone-plus-azithromycin-treated group and the ceftriaxone-treated group. Notably, the analysis of cell surface markers in the ceftriaxone-plus-azithromycin combination group exhibited upregulation of presumed immune checkpoint ligand CD86 and major histocompatibility complex class II in neutrophils and CD11b-positive CD11c-positive (CD11b(+) CD11c(+)) macrophages and dendritic cells, as well as downregulation of immune checkpoint receptors cytotoxic-T lymphocyte-associated antigen 4 and programmed death 1 in T helper and T regulatory cells. Our data demonstrate that the survival benefits of ceftriaxone-plus-azithromycin therapy occur through modulation of immune checkpoints in mouse pneumococcal pneumonia. In addition, immune checkpoint molecules may be a novel target class for future macrolide research.

Panax ginseng aqueous extract prevents pneumococcal sepsis in vivo by potentiating cell survival and diminishing inflammation

BACKGROUND

More than 50% of sepsis cases are caused by Streptococcus pneumoniae, and hospital mortality related to sepsis comprises 52% of all hospital deaths. Therefore, sepsis is a medical emergency, and any treatment against the agent that produces it, is welcome.

PURPOSE

The role of Panax ginseng C.A. Meyer (Araliaceae) aqueous extract in bacterial infection in vivo is not well understood. Here, the protective effect of Korean red ginseng (KRG) extract against pneumococcal infection and sepsis was elucidated.

STUDY DESIGN

In this study, mice were administrated KRG (25, 50, 100 mg/kg) for 15 days, and then infected with a lethal S. pneumoniae strain. Survival rate, body weight, and colonization were determined.

METHODS

The RAW 264.7 macrophage cells were infected with S. pneumoniae and cell viability was assessed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Inflammation was examined using an enzyme-linked immunosorbent assay (ELISA) and hematoxylin and eosin (HE) staining while gene expression was determined using western blotting.

RESULTS

KRG-pre-treated mice (100 mg/kg of KRG) had significantly higher survival rates and body weights than those of the non-treated controls; KRG-pre-treated mice had lower bacterial number and morbidity than those of the non-treated controls. 100 mg/kg of KRG administration decreased cytokine levels including tumor necrosis factor (TNF)-α (897 and 623 pg/ml, control and KRG groups, respectively, P < 0.05) and interleukin (IL)-1β (175 and 127 pg/ml, control and KRG groups, respectively, P = 0.051), nitric oxide level (149 and 81 nM, control and KRG groups, respectively, P < 0.05), and neutrophil infiltration 48 h post-infection, in vivo. In pneumococcal infection, KRG pre-treatment downregulated toll-like receptor (TLR) 4 and TNF-ɑ expressions in RAW 264.7 macrophage cells and increased cell survival by activating phosphoinositide 3-kinase (PI3K)/AKT signaling.

CONCLUSION

Taken together, 100 mg/kg of KRG appeared to protect host cells from lethal pneumococcal sepsis by inhibiting inflammation as well as by enhancing bacterial clearance thereby reinforcing cell survival against pneumococcal infection.

In Vitro Fractional Inhibitory Concentration (FIC) Study of Cefixime and Azithromycin Fixed Dose Combination (FDC) Against Respiratory Clinical Isolates

INTRODUCTION

Acute respiratory infections (ARI) contribute to more than 75% of health care seeking in primary health care facilities in India. Respiratory tract infections (RTIs) are managed frequently by β-lactam, macrolide and fluroquinolone class of antibiotics. However, these recommended classes of antibiotic have shown resistance in community settings. Antibiotic combinations may provide broader spectrum not only in terms of coverage but also to overcome multiple resistance mechanisms overcoming individual class limitations.

AIM

The study aimed to determine In vitro interactions interpreted according to calculated fractional inhibitory concentration (FIC) index between cefixime and azithromycin against common respiratory clinical isolates.

MATERIALS AND METHODS

Forty four bacterial respiratory clinical isolates from microbiology department of tertiary care hospital from Mumbai were used to determine the minimum inhibitory concentration (MIC) values of cefixime and azithromycin. Synergy testing of cefixime combination with azithromycin was performed by checkerboard method. Interaction was determined according to calculated FIC index.

RESULTS

MIC values were ranging from 2-128 μg/ml and 0.24-128 μg/ml for cefixime and azithromycin respectively against K.pneumoniae, M.catarrhalis, S.pneumoniae and H.influenzae isolates. All the tested isolates were resistant to cefixime. Azithromycin resistance was noted in all the isolates except six M. catarrhalis isolates. FIC index showed synergy and additive effect in 66% (29/44) and 34% (15/44) all bacterial clinical isolates. Maximum synergy between cefixime and azithromycin was observed against K. pneumoniae in 91% isolates.

CONCLUSION

This is one of the first attempts to check the rationality of fixed dose antibiotic combination of cefixime and azithromycin in India market. Though results of this study cannot be generalized considering the limitations of low sample size and in vitro model, our data provides stepping stone for further validation of cefixime and azithromycin fixed dose combinations (FDCs) in clinical setting by conducting randomized controlled trials. We think that judicious and rational use of FDCs may help to reduce the risk of selection of further drug resistance along with better clinical outcome.

Recent advances in our understanding of Streptococcus pneumoniae infection

A number of significant challenges remain with regard to the diagnosis, treatment, and prevention of infections with Streptococcus pneumoniae (pneumococcus), which remains the most common bacterial cause of community-acquired pneumonia. Although this infection is documented to be extremely common in younger children and in older adults, the burden of pneumonia it causes is considerably underestimated, since the incidence statistics are derived largely from bacteremic infections, because they are easy to document, and yet the greater burden of pneumococcal pneumonias is non-invasive. It has been estimated that for every bacteremic pneumonia that is documented, three non-bacteremic infections occur. Management of these infections is potentially complicated by the increasing resistance of the isolates to the commonly used antibiotics. Furthermore, it is well recognized that despite advances in medical care, the mortality of bacteremic pneumococcal pneumonia has remained largely unchanged over the past 50 years and averages approximately 12%. Much recent research interest in the field of pneumococcal infections has focused on important virulence factors of the organism, on improved diagnostic and prognostication tools, on defining risk factors for death, on optimal treatment strategies involving both antibiotics and adjunctive therapies, and on disease prevention. It is hoped that through these endeavors the outlook of pneumococcal infections will be improved.

Contemporary use of ceftaroline fosamil for the treatment of community-acquired bacterial pneumonia: CAPTURE study experience

The Clinical Assessment Program and Teflaro(®) Utilization Registry (CAPTURE) is a multicenter cohort study designed to collect information on the contemporary use of ceftaroline fosamil in the US. Data collected from 398 evaluable patients with community-acquired bacterial pneumonia (CABP) (mean age 64 years) during the first 18 months of the study are presented. Most patients had co-morbidities (76%; primarily structural lung disease), and ≧2 signs and symptoms of CABP (76%). Overall clinical success was 79% which varied little with ceftaroline fosamil usage (monotherapy vs concurrent therapy; first-line vs second-line therapy). Most patients were discharged home (60%) or to another healthcare facility (35%). These data suggest that ceftaroline, in contemporary clinical use, is an effective antibiotic for the treatment of patients with CABP, including those with significant co-morbidities or who required a change of their prior antibiotic therapy.

Burden of antibiotic resistance in common infectious diseases: role of antibiotic combination therapy

Globally, antimicrobial resistance is alarming concern especially in commonly reported disease entities like respiratory tract infection, enteric fever and infections associated with gram-negative bacilli (GNB). Rational use of antimicrobial drugs reported significant decrease in bacterial burden and may also reduce the risk of disease progression. However, at times in particular indication, certain patient and pathogen factor limits the selection and use of specific antibiotic therapy while in some case, due to presence of additional risk factor, aggressive therapy is required to achieve clinical reemission and prevent complications. Delay in start of suitable antibiotic therapy is another imperative factor for treatment failure and rise of drug resistance. With rapidly increasing antibiotic resistance and decline in new antibiotic drug development, the toughest challenge remains to maintain and preserve the efficacy of currently available antibiotics. Therefore, the best rational approach to fight these infections is to 'hit early and hit hard' and kills drug-susceptible bacteria before they become resistant. The preferred approach is to deploy two antibiotics that produce a stronger effect in combination than if either drug were used alone. Various society guidelines in particular indications also justify and recommend the use of combination of antimicrobial therapy. Combination therapies have distinct advantage over monotherapy in terms of broad coverage, synergistic effect and prevention of emergence of drug resistance.

Initial use of one or two antibiotics for critically ill patients with community-acquired pneumonia: impact on survival and bacterial resistance

INTRODUCTION

Several guidelines recommend initial empirical treatment with two antibiotics instead of one to decrease mortality in community-acquired pneumonia (CAP) requiring intensive-care-unit (ICU) admission. We compared the impact on 60-day mortality of using one or two antibiotics. We also compared the rates of nosocomial pneumonia and multidrug-resistant bacteria.

METHODS

This is an observational cohort study of 956 immunocompetent patients with CAP admitted to ICUs in France and entered into a prospective database between 1997 and 2010.

RESULTS

Initial adequate antibiotic therapy was significantly associated with better survival (subdistribution hazard ratio (sHR), 0.63; 95% confidence interval (95% CI), 0.42 to 0.94; P = 0.02); this effect was strongest in patients with Streptococcus pneumonia CAP (sHR, 0.05; 95% CI, 0.005 to 0.46; p = 0.001) or septic shock (sHR: 0.62; 95% CI 0.38 to 1.00; p = 0.05). Dual therapy was associated with a higher frequency of initial adequate antibiotic therapy. However, no difference in 60-day mortality was found between monotherapy (β-lactam) and either of the two dual-therapy groups (β-lactam plus macrolide or fluoroquinolone). The rates of nosocomial pneumonia and multidrug-resistant bacteria were not significantly different across these three groups.

CONCLUSIONS

Initial adequate antibiotic therapy markedly decreased 60-day mortality. Dual therapy improved the likelihood of initial adequate therapy but did not predict decreased 60-day mortality. Dual therapy did not increase the risk of nosocomial pneumonia or multidrug-resistant bacteria.

Severe community-acquired pneumonia treated with β-lactam-respiratory quinolone vs. β-lactam-macrolide combination

BACKGROUND

This study aimed to compare the outcome of patients with severe community-acquired pneumonia (SCAP) treated with the combination of either β-lactam-quinolone (βQ) or β-lactam-macrolide (βM) antibiotics.

METHODS

We retrospectively studied a cohort of patients with SCAP treated from January 2000 to December 2010 at a mixed university-level intensive care unit (ICU). APACHE II score, SCAP severity assessed by IDSA/ATS score, first antibiotic treatment initiated during the initial 24 h of admission, ICU and hospital length of stay (LOS), and ICU, hospital, 30 and 60-day mortalities were assessed.

RESULTS

Altogether, 210 patients with SCAP were analyzed, 104 in the βQ arm and 106 in the βM arm. Median APACHE II scores on admission were higher in the βM group (22 vs. 18, P = 0.003). More patients in the βQ group required mechanical ventilation (63.1% vs. 42.5%, P = 0.004) and fulfilled IDSA/ATS SCAP criteria (n = 87; 83.7%) than those in the βM group (n = 73; 68.9%; P = 0.015). Thirty-day mortality was 16.3% in the βQ group and 24.5% in the βM group (P = 0.17), and with septic shock mortality was 19.6% and 32.6%, respectively (P = 0.16). On APACHE II and IDSA/ATS SCAP score adjusted multivariate logistic regression analysis, the βM group had a slightly higher but not significant odds ratio (OR) for a 30-day mortality compared to the βQ group (OR 1.4; 95% CI, 0.62-3.0; P = 0.44).

CONCLUSION

Thirty-day mortality rate of SCAP patients did not differ whether they were treated with either βQ or βM combination.