Aerobic Gram-negative Bacteria Research Articles

CLINICAL STUDY OF WOUND INFECTION FOLLOWING GASTROENTEROLOGICAL SURGERY

Post-operative wound infection was reviewed using clinical factors and bacteriological examination in 102 and 104 patients who underwent upper gastroenterological and colorectal surgery, respectively. Although the positive ratio of the bacterial culture obtained from the upper gastroenterological operative wound showed no statistically significant difference between the positive and negative wound infection groups, the positive ratio of the bacterial culutre in the wound infection group who had colorectal surgery was higher than that of the no infection group with a statistically significant difference (p<0.05). Aerobic Gram-negative rods and anaerobic bacteria were frequently isolated from the operative wound in the colorectal surgery wound infection group. Aerobic Gram-positive cocci from infectious wounds were often isolated in upper gastroenterological surgery, as compared with anaerobic bacteria in colorectal surgery. The incidence at which the same organisms were obtained from the operative wound were isolated as a cause of wound infection was higher in colorectal surgery. Furthermore, wound infection often occurred in bacterial culture negative cases from operative wounds in upper gastroenterological surgery. In conclusion, the post-operative wound infection is associated with the bacterial contamination occurred in surgery for lower intestine, but not upper intestine.

Aerobic gram-positive and gram-negative bacteria exhibit differential sensitivity to and transformation of 2,4,6-trinitrotoluene (TNT).

A systematic evaluation of the ability of different bacterial genera to transform 2,4,6-trinitrotoluene (TNT), and grow in its presence, was conducted. Aerobic Gram-negative organisms degraded TNT and evidenced net consumption of reduced metabolites when cultured in molasses medium. Some Gram-negative isolates transformed all the initial TNT to undetectable metabolites, with no adsorption of TNT or metabolites to cells. Growth and TNT transformation capacity of Gram-positive bacteria both exhibited 50% reductions in the presence of approximately 10 microg TNT ml-1. Most non-sporeforming Gram-positive organisms incubated in molasses media amended with 80 microg TNT ml-1 became unculturable, whereas all strains tested remained culturable when incubated in mineral media amended with 98 microg TNT ml-1, indicating that TNT sensitivity is linked to metabolic activity. These results indicate that the microbial ecology of soil may be severely impacted by TNT contamination.

CQ-397 and CQ-414: antimicrobial activity and spectrum of two fluoroquinolone---cephalosporin, dual-action compounds with carboxamido bonds.

OBJECTIVE: To evaluate the potential spectrum of activity of two novel dual-action compounds with carboxamido bonds (CQ-397 and CQ-414; Laboratorios Aranda, San Rafael, Mexico) against human pathogens. METHODS: Approximately 800 Gram-positive and Gram-negative aerobic clinical bacteria were tested in vitro using the Mueller-Hinton broth microdilution method of the National Committee of Clinical Laboratory Standards. RESULTS: CQ-397 (cefamandole+enrofloxacin) and CQ-414 (cefamandole+norfloxacin) were equally potent against Enterobacteriaceae (MIC90 range, 0.06--0.5 microg/mL and 0.06--1 microg/mL, respectively). Citrobacter freundii (MIC90, 4 microg/mL) and Providencia spp. (MIC90, >32 microg/mL) exhibited elevated study drug MICs. Enterobacteriaceae resistant to fluoroquinolones generally remained resistant. CQ-397 and CQ-414 were active against Stenotrophomonas maltophilia (MIC90, 4 microg/mL) and oxacillin-susceptible staphylococci (MIC90, 0.25 microg/mL), but not oxacillin-resistant Staphylococcus aureus (MIC90, >32 microg/mL), Staphylococcus epidermidis (MIC90, 8 microg/mL), and enterococci (MIC90s, 8 to >32 microg/mL). There was no difference in the dual-action drug activity (MIC90, 2 microg/mL) between penicillin-susceptible and -resistant pneumococci. Haemophilus influenzae and Moraxella catarrhalis were very susceptible (MIC range, less-than-or-equal0.015--0.06 microg/mL) to both compounds. CONCLUSIONS: The activity of these novel dual-action compounds, formed from the bonding of older antimicrobials, warrants further investigation for potential human and/or animal health use, including toxicology and pharmacokinetics.

Mechanisms of resistance to piperacillin of Enterobacter cloacae strains differ by antibiotic prescription policy

During a study of piperacillin resistance among aerobic Gram-negative bacteria, 18 resistant strains of Enterobacter cloacae were obtained from a General Hospital in Rotterdam and 13 from a University Hospital in Amsterdam. The patterns of antibiotic susceptibilities were different: the Amsterdam strains were generally resistant to penicillins, the third generation cephalosporins and temocillin, whereas the Rotterdam strains were more often sensitive to the third generation cephalosporins and temocillin but more resistant to penicillins. Isoelectric focusing and substrate profiles showed the presence of chromosomal Class 1 β-lactamase in ten of the Amsterdam strains: in three strains a plasmid mediated TEM-1 enzyme was detected. In contrast 15 of the 18 Rotterdam strains possessed a plasmid mediated β-lactamase, ten of which were TEM-2. Eight of the ten strains with the TEM-2 enzyme harboured a transferable plasmid coding for resistance to piperacillin. Endonuclease analysis of plasmid DNA from these eight strains revealed an identical pattern in seven strains. Different selective pressures were operative in each hospital. In Amsterdam the general use of cefotaxim and piperacillin favoured emergence of strains with derepressed chromosomal Class 1 β-lactamase, whereas in Rotterdam the use of cefuroxime favoured the spread of a plasmid, encoding TEM-2 β-lactamase.

Comparative Effects of Levofloxacin and Ofloxacin on the Normal Oral and Intestinal Microflora

The aim of the study was to study the ecological effects of levofloxacin, compared to that of ofloxacin, on the oral and intestinal human microflora. 10 healthy volunteers received levofloxacin (500 mg) and 10 subjects were given ofloxacin (400 mg) perorally, once daily for 7 days. Saliva and stool samples were obtained prior to drug administration, during administration (days 2, 4 and 7), and after withdrawal of the agents (days 9, 11, 14 and 21). The concentrations of levofloxacin and ofloxacin in the saliva and faecal samples, respectively, were assayed, and quantitative and qualitative microbiological analyses were performed. Oral administration of levofloxacin and ofloxacin led to low drug concentrations in the saliva, which corresponded with mild disturbances in the oral microflora. High drug levels were obtained in the intestinal tract, and both agents caused a selective reduction in the normal microflora, mainly directed towards aerobic Gram-negative bacteria. There was no significant difference between levofloxacin and ofloxacin, regarding ecological effects on the normal oral and intestinal microflora. From an ecological point of view, these agents acted favourably, since no major selection of resistant strains occurred in the normal microflora during administration.

Cefepime: a fourth-generation parenteral cephalosporin.

To review the chemistry, microbiology, pharmacokinetics, therapeutic efficacy, adverse effect profile, drug interactions, dosing, and administration of cefepime, a new fourth-generation parenteral cephalosporin. A MEDLINE search of the available literature, including clinical trials and reviews, was performed. Abstracts presented at recent scientific conferences and current publications were also reviewed. In vitro and preclinical data were included, as well as data from Phase II and III clinical trials. Cefepime is an extended-spectrum parenteral cephalosporin antibiotic active in vitro against a broad spectrum of gram-positive and gram-negative aerobic bacteria. The gram-positive spectrum is similar to that of cefotaxime, the gram-negative spectrum is similar to that of ceftazidime, and many, though not all, organisms resistant to these two agents remain susceptible to cefepime, prompting the fourth-generation designation. Cefepime has a high affinity for penicillin-binding proteins and, due to its zwitterionic configuration, rapidly penetrates outer-membrane porin channels of bacteria. Beta-lactamases appear to have a low affinity for the drug. Cefepime has a decreased propensity to induce beta-lactamases compared with other beta-lactam antibiotics. Cefepime has a pharmacokinetic disposition similar to that of other renally eliminated cephalosporins, with a half-life of approximately 2 hours. Cefepime has demonstrated clinical efficacy against a variety of infections, including urinary tract infections, pneumonia, and skin and skin structure infections. Cefepime is generally well tolerated.

The influence of temperature and gas mixtures on the growth of the intrinsic micro-organisms on cut endive: predictive versus actual growth

Effects of temperature and carbon dioxide concentration on the growth of mesophilic aerobic count (MAC), psychrotrophic, Gram-negative bacteria, pseudomonads and lactic acid bacteria were investigated in a case-study of minimally processed endive. When plotting population density against time, a distinct lag time was not observed. In a temperature range from 4.3–16.1°C, both combined Arrhenius–Ratkowsky-restricted growth models were used to model growth of these groups of micro-organisms. Temperature dependence of the growth rate constant for pseudomonads and psychrotrophic, Gram-negative bacteria were similar, whereas the growth rate constant of the MAC was much more temperature dependent. A combined exponential (CO 2)–Arrhenius (temperature)-restricted growth model was selected to model the number of pseudomonads and an exponential (CO 2)–Ratkowsky (temperature)-restricted growth model was selected to model the growth of MAC on cut endive. The restricted growth model was differentiated with respect to time to obtain a dynamic restricted growth model. Temperature shift-up and shift-down experiments were performed. Use of the Arrhenius equation for the temperature dependence of the growth rate constant and parameter estimates obtained under constant CO 2and temperature conditions only partially allowed us to predict the microbial evolution of minimally processed endive under dynamic conditions. Especially under temperature shift-down conditions, a systematic underestimation of growth was observed.

Antibiotic therapy for preterm premature rupture of the membranes

Amniotic fluid studies and placental histopathological evaluation have confirmed the association between intrauterine infection and preterm premature rupture of the membranes (pPROM). This association is increasingly strong with pPROM at early gestational ages. The organisms associated with pPROM include a broad spectrum of aerobic and anaerobic gram-positive and gram-negative bacteria. In many cases, the patient presenting with pPROM will have overt intrauterine infection necessitating delivery. For those amenable to expectant management, the clinical course is usually of brief latency between membrane rupture and delivery. A number of well-designed prospective clinical trials have evaluated the utility of antibiotic treatment during the expectant management of pPROM. Taken together, these studies suggest broad spectrum antibiotic treatment of this population to enhance pregnancy prolongation, and to reduce maternal and neonatal infectious morbidity. There are some data suggesting the potential for a reduction in neonatal gestational age-dependent morbidity. We recommend aggressive adjunctive antibiotic treatment to prolong pregnancy and reduce morbidity in patients with pPROM, at gestations remote from term, when a significant improvement in neonatal outcome can anticipated with expectant management.

The genus Sphingomonas: physiology and ecology

Exploitation of the metabolic capabilities of the genus Sphingomonas could provide important commercial benefits to biotechnology. Recent advances have demonstrated that these organisms have unique abilities to degrade refractory contaminants, to serve as bacterial antagonists to phytopathogenic fungi, and to secrete the highly useful gellan exopolysaccharides. Unfortunately, Sphingomonas are also animal pathogens and can readily degrade the copper pipes in drinking water distribution systems. The closely related Zymomonas could be important for commercial ethanol production. These Gram-negative aerobic bacteria are characterized by an outer membrane that contains glycosphingolipids, but lacks lipopolysaccharide. Their distribution in environmental samples has not been systematically examined as yet.

Bacteriologic and clinical applications of a new extended-spectrum parenteral cephalosporin

Although third-generation cephalosporins have been considered the backbone of antibiotic therapy for the treatment of many kinds of serious infections, including those in hospitalized patients, lack of activity against some important pathogens still exists among currently available drugs. In addition, increasing accounts of antibiotic resistance, particularly in the hospital environment, are of deep concern and have thus led to the need for the development of newer antimicrobial agents. Cefepime is a now parenteral cephalosporin with an extended spectrum of antibacterial activity that includes both aerobic gram-negative and gram-positive bacteria. It is also active against many gram-negative organisms resistant to ceftriaxone and cefotaxime, as well as many strains of Enterobacter and Citrobacter resistant to ceftazidime. Cefepime appears to be less likely to select out resistant organisms, and it may be less likely to change hospital flora than currently available antimicrobials. Cefepime has been shown to be very well tolerated and effective in the treatment of a variety of infections including moderate-to-severe pneumonia (including cases associated with concurrent bacteremia), complicated and uncomplicated urinary tract infections (also including cases associated with concurrent bacteremia), and skin and skin-structure infections. Clinical response rates are > or = 75% for most infections and have been comparable to ceftazidime in comparative trials. In addition, pretreatment susceptibility testing indicates that >94% of organisms isolated in patients enrolled in clinical trials were susceptible to cefepime.

Evaluation of tributyltin resistance in marine sediment bacteria

Tributyltin (TBT) resistance of aerobic and anaerobic bacteria isolated from TBT-contaminated coastal sediments in Arcachon Bay, France, was determined and compared with taxonomically similar bacteria originating from diverse non-TBT-contaminated environments. The minimum inhibitory concentrations (MICs) showed that TBT was toxic to most of the bacteria studied at concentrations above 2.1 μM (0.7 mg/L) for clostridia, 76 μM (25 mg/L) for pseudomonads, and 3 mM (1000 mg/L) for enterobacteria. The aerobic or facultative anaerobic Gram-negative bacteria (pseudomonads and enterobacteria) presented the highest TBT tolerance. No difference in TBT resistance was observed between strains originating from the polluted site and strains originating from non-TBT-polluted environments (thermal muds, Hospital of Bordeaux, etc.), suggesting that a TBT-polluted environment did not select for more specific resistant bacteria. It should be noted that the bacteria tested were found to be tolerant to TBT concentrations 1000 times higher than those found in the polluted site. Further, all strains presented the same pattern of metal and pharmaceutical antibiotic sensitivity despite the origin of the environment (TBT-polluted or non-TBT-polluted sediments). Six strains of Pseudomonas stutzeri isolated from Arcachon Harbor and one strain of Pseudomonas aeruginosa originating from the bacterial collection of Bordeaux Hospital have been selected for their TBT resistance. As antibiotic resistance, metal or organometal resistance can be plasmid mediated. However, among these TBT-resistant strains no plasmid was detected.Key words: TBT resistance, coastal environment, clostridia, pseudomonads, enterobacteria.

Comparative susceptibilities of Klebsieila species, Enterobacter species, and Pseudomonas aeruginosa to 11 antimicrobial agents in a tertiary-care university hospital

The in vitro activity of cefepime was compared versus that of 10 antimicrobial agents commonly used in the treatment of serious infections caused by common aerobic gram-negative bacteria: aztreonam, cefoperazone, ceftazidime, ceftriaxone, ciprofloxacin, gentamicin, imipenem, piperacillin, ticarcillin-clavulanic acid, and tobramycin. We tested 30 clinical isolates representing a cross section of Klebsiella and Enterobacter species and Pseudomonas aeruginosa collected at our tertiary-care university hospital. The most potent beta-lactams were imipenem and cefepime, which demonstrated significant activity against the majority of strains in all 3 genera of bacteria tested, as did ciprofloxacin and tobramycin. Ceftazidime was active against Pseudomonas aeruginosa but was less potent against Klebsiella and Enterobacter spp. Cefoperazone and ceftriaxone were less active than ceftazidime against Pseudomonas aeruginosa. Cefepime was found to be highly active against many resistant organisms that traditionally have been difficult to treat.

Selective intestinal decontamination with norfloxacin reduces bacterial translocation in ascitic cirrhotic rats exposed to hemorrhagic shock.

Bacterial translocation (BT) can be involved in the pathogenesis of severe infections due to bacteria of enteric origin that complicates bleeding cirrhotic patients. To assess the effect of hemorrhagic shock (HS) on the incidence of BT and if selective intestinal decontamination (SID) reduces this incidence, we studied six groups of Sprague-Dawley rats: ascitic rats, ascitic rats exposed to HS with and without previous norfloxacin prophylaxis, healthy rats, and healthy shocked rats with and without previous norfloxacin prophylaxis. BT tended to be higher in ascitic rats with shock than without shock (69% vs. 41%, P = .15) and was significantly higher in healthy rats with than without shock (50 percent vs. 0 percent, P = .01). Norfloxacin significantly reduced translocation in ascitic shocked rats in comparison with nondecontaminated ascitic shocked rats (31 percent vs. 69 percent, P = .038). This effect was due mainly to a reduction of gram-negative BT (O percent vs. 37 percent, P = .008). In addition, norfloxacin prevented translocation in healthy shocked rats. Accordingly, aerobic gram-negative bacteria disappeared from fecal flora in all rats administered norfloxacin, except for Klebsiella species in one control rat. Cecal severe submucosal edema, chronic inflammatory infiltrate, and intestinal lymphangiectasia were significantly more frequent in ascitic rats than in control rats. Intestinal mucosal injury related with HS, particularly subepithelial cecal edema, was observed only in ascitic shocked rats. In conclusion, HS increases the incidence of BT both in ascitic cirrhotic and healthy rats. Norfloxacin reduces significantly the incidence of translocation after shock, especially in those cases caused by aerobic gram-negative bacilli.

Selective intestinal decontamination with norfloxacin reduces bacterial translocation in ascitic cirrhotic rats exposed to hemorrhagic shock

Bacterial translocation (BT) can be involved in the pathogenesis of severe infections due to bacteria of enteric origin that complicates bleeding cirrhotic patients. To assess the effect of hemorrhagic shock (HS) on the incidence of BT and if selective intestinal decontamination (SID) reduces this incidence, we studied six groups of Sprague-Dawley rats: ascitic rats, ascitic rats exposed to HS with and without previous norfloxacin prophylaxis, healthy rats, and healthy shocked rats with and without previous norfloxacin prophylaxis. BT tended to be higher in ascitic rats with shock than without shock (69% vs. 41%, P = .15) and was significantly higher in healthy rats with than without shock (50 percent vs. 0 percent, P = .01). Norfloxacin significantly reduced translocation in ascitic shocked rats in comparison with nondecontaminated ascitic shocked rats (31 percent vs. 69 percent, P = .038). This effect was due mainly to a reduction of gram-negative BT (O percent vs. 37 percent, P = .008). In addition, norfloxacin prevented translocation in healthy shocked rats. Accordingly, aerobic gram-negative bacteria disappeared from fecal flora in all rats administered norfloxacin, except for Klebsiella species in one control rat. Cecal severe submucosal edema, chronic inflammatory infiltrate, and intestinal lymphangiectasia were significantly more frequent in ascitic rats than in control rats. Intestinal mucosal injury related with HS, particularly subepithelial cecal edema, was observed only in ascitic shocked rats. In conclusion, HS increases the incidence of BT both in ascitic cirrhotic and healthy rats. Norfloxacin reduces significantly the incidence of translocation after shock, especially in those cases caused by aerobic gram-negative bacilli. (Hepatology 1996 Apr;23(4):781-7)

Comparative study of in vitro activity of NM394 and four other new quinolones against clinical isolates from patients with obstetric and gynecologic infections

In vitro antimicrobial activity of NM394 (6-fluoro-1-methyl-7-(1-piperazinyl)-4-oxo-4H-[1,3]thiazeto[3,2-a]quinoline-3-carboxylic acid) against clinical isolates collected from samples (uterine contents, ascites, pus, etc) obtained from patients with obstetric and gynecologic infections was investigated and compared with that of four other quinolones: norfloxacin, ofloxacin, ciprofloxacin, and tosufloxacin. Among 80 strains of aerobes and 60 strains of anaerobes determined, the minimum inhibitory concentrations (MICs) of NM394 for 50% inhibition against methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant S aureus (MRSA), Streptococcus agalactiae, Escherichia coli, Peptostreptococcus magnus, Bacteroides fragilis, and Prevotella bivia were 0.39, 25, 0.78, 0.0125, 0.2, 3.13, and 0.78 μg/mL, respectively, and the MICs for 90% inhibition against MSSA, MRSA, S agalactiae, E coli, P magnus, B fragilis, and P bivia were 1.56, > 100, 1.56, 0.025, 0.39, 6.25, and 1.56 μg/mL, respectively. The antimicrobial activity of NM394 against gram-positive bacteria was less than that of tosufloxacin but was comparable to that of ofloxacin and ciprofloxacin. Judging from its antibacterial activity, the efficacy of NM394 against infections caused by MRSA might be expected to be similar to that of the other four quinolones. The antibacterial activity of NM394 against aerobic gram-negative bacteria, especially E coli, was greater than that of the other new quinolones. However, against anaerobic gram-negative bacteria, especially B fragilis, the antibacterial activity of NM394 appeared to be less than that of the other agents. The clinical implications of these results, if any, remain unknown until further clinical therapeutic trials are conducted.

Fleroxacin Overview

Fleroxacin is a new oral and intravenous trifluorinated 4-quinolone, which acts by inhibiting the essential bacterial enzyme DNA gyrase. Fleroxacin exhibits a broad spectrum of action, characterized by pronounced activity against aerobic gram-negative bacteria, but also against gram-positive pathogens such as staphylococci. Fleroxacin is distinguished by its excellent bioavailability, high concentrations in the plasma and other body fluids, good tissue penetration, and a long half-life of 10-12 h, thus allowing once-a-day administration. A single oral dose of 400 mg fleroxacin is effective in uncomplicated cystitis in women, uncomplicated gonococcal infections, bacterial enteritis, and traveler's diarrhea. A single daily dose of 200 mg administered for 3 days is effective in uncomplicated urinary tract infection (UTI), while longer treatment and higher doses may be required in acute uncomplicated pyelonephritis and complicated UTI. Skin, soft tissue, bone and joint infections, and lower respiratory tract infections including exacerbation of chronic bronchitis and non-pneumococcal pneumonia are further indications for fleroxacin.

Antimicrobial and mercury resistance in aerobic gram-negative bacilli in fecal flora among persons with and without dental amalgam fillings.

Antimicrobial resistance is more widespread than can be accounted for as being a consequence of the selection pressure caused by the use of antibiotics alone. In this study, we tested the hypothesis that a high mercury content in feces might select for mercury-resistant bacteria and thus for antimicrobial resistance linked to mercury resistance. Three subject groups with different exposures to dental amalgam fillings were compared. None of the subjects had taken antimicrobial agents during the three preceding months or longer. The group exposed to dental amalgam (n = 92) had 13 times more mercury in feces than the group that had never been exposed to amalgam (n = 43) and the group whose amalgam fillings had been removed (n = 56). No significant differences in either mercury resistance or antibiotic resistance in the fecal aerobic gram-negative flora of these subject groups were seen. The following antimicrobial resistance frequencies were detected with a replica plating method: > or = 1% resistance was seen in 40% of the subjects for ampicillin, 14% of the subjects for cefuroxime, 6% of the subjects for nalidixic acid, 14% of the subjects for trimethoprim, 19% of the subjects for sulfamethoxazole, and 25% of the subjects for tetracycline. The amount of mercury in feces derived from amalgam was not selective for any resistance factors in aerobic gram-negative bacteria, but antimicrobial resistance was widespread even among healthy subjects with no recent exposure to antibiotics.

The Comparative In Vitro Activity of FK-037 (Cefoselis), a New Broad-Spectrum Cephalosporin

FK-037, a new parenteral cephalosporin, was active against clinical isolates of both gram-positive and gram-negative aerobic bacteria. The activity of FK---037 was similar to that of cefpirome and cefepime and generally superior to that of ceftazidime. Methicillin-resistant staphylococci were less susceptible than methicillin-sensitive isolates but most remained within the sensitive range. All streptococci and Enterobacteriaceae were sensitive as were the majority of isolates of Acinetobacter spp. and Pseudomonas aeruginosa. There was resistance amongst other non-fermentative gram-negative bacilli but this was species specific and most pseudomonads were sensitive, with resistance seen in Stenotrophomonas maltophilia, Alcaligenes spp. and Flavobacterium spp.

THE NEWER CEPHALOSPORINS: Aztreonam and Imipenem

Many of the antimicrobial agents described here exhibit great advances over older drugs in terms of antimicrobial spectrum, clinical utility, and, sometimes, safety. The newer cephalosporins are useful for treatment of many common outpatient and inpatient infections. Aztreonam provides excellent coverage against a broad range of aerobic gram-negative bacteria, without the toxicity associated with aminoglycosides. Imipenem exhibits activity against an impressive array of pathogens. These antimicrobials are expensive, however, and some offer no advantages over older agents. Finally, all--including imipenem--are faced with increasing resistance of bacteria.

Cervical Necrotizing Fasciitis: Clinical Manifestations and Management

Forty-five cases of cervical necrotizing fasciitis are reported, and their clinical, bacteriologic, and therapeutic implications are considered. Fasciitis was of dental origin in 78% of cases, pharyngeal in 16%, and surgical or posttraumatic in 6%. The condition extended to the face in 22% of cases, to the lower part of the neck in 56%, and to the mediastinum in 40%. Soft-tissue cultures were positive in 78% of cases. Anaerobes were isolated along with aerobes in 49% of cases (mean, 2.2 isolates per patient) and in pure culture in 22%. Treatment included surgical debridement and drainage and the administration of antibiotics active against both anaerobic and gram-negative aerobic bacteria. Hyperbaric oxygen was used for adjunctive treatment. The bacteria involved did not affect clinical manifestations, extension, or mortality. The survival rate among our patients was 78%. Mortality was significantly higher among cases with mediastinal extension (44% vs. 7%; P < .01); thus the prompt recognition and drainage of sites of mediastinal extension are of critical importance. Other risk factors for death were an age of > 70 years, underlying diabetes, the development of septic shock within 24 hours after admission, and prolonged prothrombin time.