Gram Stain Results Research Articles

Antibiotic therapy in otorhinolaryngology

ZusammenfassungZunächst werden die allgemeinen Prinzipien zur Antibiotikatherapie vorgestellt. Die Indikationsstellung muss gut überlegt sein. So dürfen z. B. die häufigen viralen Infektionen an Hals, Nase und Ohren, ebenso wie zahlreiche bakterielle Infektionen nicht antibiotisch behandelt werden. Aufgrund der derzeitigen Antibiotikasensibilität der hauptsächlichen HNO-Keime wird der Antibiotikawahl nach der kalkulierten Therapie ein besonderes Augenmerk geschenkt, jedoch auch den Vorteilen der Optimierung dieser Therapie durch Zuhilfenahme des Gram-Präparat-Ergebnisses (superkalkulierte Therapie) und des Antibiogramms (gezielteTherapie). Es wird daran erinnert, dass die Eiterbeschaffenheit der erste Schritt zur Erregerdiagnostik sein kann. Der Schweregrad der Infektion bestimmt die Indikation einer oralen oder parenteralen Therapie. Grundsätzlich ist eine Antibiotikatherapie nach 2–3 Tagen zu überprüfen. Eine Zusammenstellung der verschiedenen HNO-Infektionen mit ähnlichem Erregerspektrum macht die Therapierichtlinien durch Vermeidung von Wiederholungen übersichtlicher. Dabei werden die aktuellen Empfehlungen der Antibiotikabehandlung zahlreicher Infektionen an Kopf und Hals bei unterschiedlichen Schweregraden aufgeführt. Nach einer Darstellung der für die verschiedenen Infektionen in Frage kommenden Antibiotika mit ihrem derzeitigen Wirkungsspektrum werden die primäre Therapie, die Therapie bei Penicillinallergie, in schweren Fällen und bei Komplikationen bzw. bei Therapieversagen angegeben.

Clinical predictors of bacterial involvement in exacerbations of chronic obstructive pulmonary disease.

The wide use of antibiotics for treatment of exacerbations of chronic obstructive pulmonary disease (COPD) lacks evidence. The efficacy is debatable, and bacterial involvement in exacerbation is difficult to verify. The aim of this prospective study was to identify factors that can help to estimate the probability that a microorganism is involved in exacerbation of COPD and, therefore, predict the success of antibiotic treatment. Clinical data and sputum samples were obtained from 116 patients during exacerbation of COPD. Bacterial infection was defined by the abundant presence of >or=1 potential pathological microorganism in relation to the normal flora in sputum. Of 116 exacerbations, 22 (19%) had bacterial involvement. The combination of a negative result of a sputum Gram stain, a relevant nonclinical decrease in lung function (compared with baseline measurements), and occurrence of <2 exacerbations in the previous year were 100% predictive of a nonbacterial origin of the exacerbation. The presence of all 3 of these clinical characteristics yielded a positive predictive value of 67% for a bacterial exacerbation. Patients presenting with an exacerbation who have a negative result of sputum Gram stain, do not have a clinically relevant decrease in lung function, and have experienced <2 exacerbations of COPD in the previous year do not require antibiotic treatment [corrected]. A treatment protocol taking into account these variables might lead to a 5%-24% reduction in unnecessary treatment with antibiotics, depending on actual prescription rates.

Evaluation of a rapid PCR assay for diagnosis of meningococcal meningitis.

We compared the results of Gram staining and culture of cerebrospinal fluid to results obtained with a rapid PCR assay for the diagnosis of meningococcal meningitis in 281 cases of suspected bacterial meningitis. PCR had a sensitivity of 97% compared to a sensitivity of 55% for culture, and the PCR specificity was 99.6%. PCR results were available within 2 h of the start of the assay.

Infective endophthalmitis caused by Bacillus cereus after cataract extraction surgery.

We describe a 72-year-old Chinese man who developed fulminant Bacillus cereus endophthalmitis 36 h after an uneventful surgery for cataract extraction. Clinical progression of disease was extremely rapid, in spite of early vitrectomy and intravitreal injection of antibiotics. Results of Gram staining showed gram-positive bacilli, and the culture was positive for B. cereus. Endophthalmitis is rare after cataract surgery (cumulative probability within 1 year, approximately 0.08%), and cases caused by B. cereus are even less common. The prognosis and plan of treatment are discussed.

Etiologic diagnosis of infective endocarditis by broad-range polymerase chain reaction: a 3-year experience.

We analyzed surgically resected endocardial specimens from 49 patients by broad-range PCR. PCR results were compared with (1) results of previous blood cultures, (2) results of culture and Gram staining of resected specimens, and (3) clinical data (Duke criteria). Molecular analyses of resected specimens and previous blood cultures showed good overall agreement. However, in 18% of patients with sterile blood cultures, bacterial DNA was found in the resected materials. When data from patients with definite or rejected cases of infective endocarditis (IE) were included, the sensitivity, specificity, and positive and negative predictive values of broad-range PCR were 82.6%, 100%, 100%, and 76.5%, respectively, overall, and 94.1%, 100%, 100%, and 90%, for cases of native valve endocarditis. The sensitivity, specificity, and positive and negative predictive values of culture of resected specimens from patients with native valve endocarditis were 17.6%, 88.9%, 75%, and 36.4%. We recommend broad-range PCR of surgically resected endocardial material in cases of possible IE, in cases of suspected IE in which blood cultures are sterile, and in cases in which organisms grow in blood cultures but only Duke minor criteria are met. We propose to add molecular techniques to the pathologic criteria of the Duke classification scheme.

Characterization of type 1851 organism isolated from activated sludge samples

Five orange pigmented filamentous strains of Eikelboom's type 1851 were isolated from bulking activated sludge, and were examined for their phylogenetic lineage, morphology, and physiology. The analysis of 16S rDNA sequence revealed that the isolates belong to Chloroflexus subdivision in green non sulfur bacteria. They shared most common features with type 1851, but the result of gram stain was negative. Furthermore, they showed polymorphic nature and gliding motility, which could not be seen in activated sludge samples. General physiological tests were conducted under aerobic conditions although they could also grow by fermentation. Good growth was generally seen on sugars. The extremely slow growth rate (0.48-0.93 day(-1)) suggests the stimulation of this type exclusively in long SRT systems fed with sugars.

Characterization of vaginal flora and bacterial vaginosis in women who have sex with women.

Bacterial vaginosis (BV) may be common among women who report having sex with women (WSW) and frequently occurs in both members of monogamous couples. The results of Gram staining of a vaginal smear were consistent with BV in 81 (25%) and intermediate in 37 (11%) of 326 WSW included in this study. Lactobacilli were detected in 64% of subjects, and 42% of subjects had H(2)O(2)-producing strains. BV was associated with a higher lifetime number of female sex partners, failure to always clean an insertive sex toy before use, and oral-anal sex with female partners. Neither recent douching nor sexual practices with male partners were associated with BV. Vaginal smears from each partner were concordant in 55 (95%) of 58 monogamous couples; BV was present in both partners in 16 couples (28%) (P<.001, compared with expected distribution). BV was common among subjects who did not douche, who did not have concurrent sex with male partners, or who did not have a new sex partner, which suggests that other risk factors for BV exist. These data support the hypothesis that sexual exchange of vaginal secretions is a possible mechanism for acquisition of BV.

Gallium uptake in complicated pancreatitis: a predictor of infection.

A retrospective evaluation was performed of the use of gallium imaging in patients with known severe pancreatitis to detect infection in pancreatic and peripancreatic fluid collections. Gallium-67 single-photon emission computed tomography (SPECT) studies were retrospectively reviewed in patients with complicated pancreatitis. Only patients who had undergone interventional procedures within 10 days of the scanning were included in our analysis. A total of 23 scans from 20 patients were reviewed. SPECT imaging was typically performed 48-72 hr after injection of the gallium. All studies were correlated with conventional CT findings. Findings from subsequent interventions (results of aspiration, Gram stains, or cultures) were used as evidence of infection. Twenty patients underwent either percutaneous or surgical drainage within 10 days of their gallium scanning. One patient underwent gallium scanning on three different occasions and underwent three different interventional procedures after each of the gallium scans, bringing the total number of cases in our study to 23. Of these 23 cases, 18 patients (78%) with gallium scans showing positive findings for infection had infected fluid; five patients (22%) with negative findings for infection on gallium scans had sterile fluid (p < 0.00001). No false-positive scans were found among our study cases, and we found no correlation between the uptake of gallium and the presence or absence of pancreatic necrosis. Gallium does not actively accumulate in all patients with severe pancreatitis, and gallium uptake does not correlate with the presence or absence of necrosis. In patients with severe pancreatitis complicated by fluid collections or inflammatory masses, gallium SPECT is a useful predictor of infection and can be used to help guide subsequent intervention. Gallium SPECT allows targeting sites of infected fluid in patients with multiple fluid collections and potentially obviates intervention in patients with sterile fluid collections.

Rhodococcus equi infection in transplant recipients: a case of mistaken identity and review of the literature

The incidence of Rhodococcus equi infection in solid-organ transplant recipients continues to rise throughout the world. Unfortunately, this opportunistic pathogen is still underestimated and potentially disregarded by physicians and microbiology laboratories due to its morphology on Gram staining. Pulmonary involvement is the most common finding in the immunocompromised host. We report a case of a 63-year-old heart-transplant recipient who presented with increasing fatigue and nonproductive cough for 3 weeks. After full evaluation, a lung abscess was demonstrated by thoracic computerized tomography (CT). Blood and sputum cultures were remarkable for heavy "diphtheroids." Although the Gram-stain result was initially interpreted as a contaminant, a clinical suspicion for Rhodococcus assisted in further investigation. Broncheoalveolar lavage and CT-guided biopsy of the lung abscess revealed heavy growth of diphtheroids. However, further evaluation by a reference laboratory demonstrated mycolic acid staining consistent with R. equi. Surgical drainage and prolonged antibiotic therapy resulted in complete remission of the pneumonia and abscess. This represents the fourth reported case of R. equi infection in a heart transplant recipient. It is imperative that all physicians and laboratory staff consider R. equi when an immunocompromised patient has any type of pneumonia, especially with abscess formation.

Socioeconomic and environmental risk factors of bacterial vaginosis in early pregnancy.

The main aim of this prospective study was to determine the socioeconomic, demographic and environmental factors that may be associated with the occurrence of bacterial vaginosis at early pregnancy in an indigent population from Central Poland. A group of 196 pregnant women was selected randomly from the patients of 10 district maternity units in the Lodz region, Central Poland. Only singleton pregnancies between 8 and 16 week of gestation were qualified for inclusion in the survey. A standard questionnaire covering medical, socioeconomic, demographic, constitutional and environmental items was administered to every subject and was verified with medical records. Cervico-vaginal swabs were collected from the women under study and tested for bacterial vaginosis (BV) according to Spiegel's criteria. Based on the results of Gram stain, BV was diagnosed in 51 women (28.5%), grade I microflora among 66 (36.9%) and grade II among 62 women (34.6%). In the univariate analysis, only single marital status proved to be an important risk factor associated with BV during pregnancy, this was confirmed in the multivariate analysis. Pregnant women who present risk factors for abnormal cervico-vaginal microflora should be covered by comprehensive prenatal surveillance, which enables early detection and treatment of this pathology. Research that identifies the causal pathways and mechanisms through which social disadvantage leads to a higher risk of preterm birth may help to reduce current socioeconomic and demographic disparities and improve pregnancy outcome.

Pneumonia after cardiac surgery is predictable by tracheal aspirates but cannot be prevented by prolonged antibiotic prophylaxis

Background. The purpose of this study was to assess the value of tracheal aspirate as a predictor of pneumonia after coronary artery bypass grafting and to evaluate the efficacy of prolonged perioperative antibiotic prophylaxis. Methods. Tracheal aspirates of 500 patients undergoing coronary artery bypass grafting were taken immediately after intubation and analyzed for microorganisms by Gram stain and semiquantitative microbiologic cultures. All patients received 2 g ceftriaxone as a single-dose perioperative antibiotic prophylaxis before operation. Results of Gram stains were available before the patients were transferred to the intensive care unit. After the results were known, both groups of patients (positive Gram stain, group 1; negative Gram stain, group 2) were randomly assigned to either conventional antibiotic prophylaxis (A), consisting of ceftriaxone 2 g on postoperative day 1, or prolonged antibiotic prophylaxis (B), with ticarcillin + clavulanic acid 3 × 5.2 g during 72 hours. Results. From 500 patients, 91 had a positive Gram stain whereas 409 had a negative one. The incidence of pneumonia was significantly higher in patients with preoperative positive tracheal aspirates (15.3%) than in patients with a negative one (3.6%; p < 0.01). However, prolonged prophylaxis did not reduce the rate of postoperative pneumonia, which was as high as 13% in untreated positive patients versus 17% in treated positive patients, and 2% in untreated negative patients versus 4% in treated patients. In patients who had pneumonia, there was a high correlation between the microorganisms found in preoperative aspirates and those observed when aspirates were repeated (100% correlation in patients with conventional antibiotic prophylaxis and 87% in those with prolonged prophylaxis). Conclusions. Early postoperative pneumonia (<7 days) is most likely caused by microorganisms that colonize the respiratory tract before operation. The risk of pulmonary infection after coronary artery bypass grafting can be predicted from the preoperative tracheal aspirates. Prolonged perioperative antibiotic prophylaxis has no efficacy in reducing the incidence of pulmonary infections.

Muslin-induced intracranial sterile abscess: A cause of visual loss after aneurysm repair

Report of a Case A68-year-old white woman developed acute onset of severe headache in 1982. Computed tomography (CT) scans of the head revealed a subarachnoid hemorrhage, and cerebral angiography demonstrated a left paraophthalmic artery aneurysm. The patient underwent aneurysm clipping, with wrapping of the base with muslin. Three weeks after surgery the patient noted mild blurred vision of the left eye. Visual acuity was 20/20 in both eyes, and there was optic disc pallor in the left eye (OS). Goldmann visual field testing was full for both eyes (OU). The patient remained visually stable for several years. In 1990, she developed painless loss of vision in the left eye. Visual acuity was 20/20 OU and there was a trace afferent pupillary defect OS; Goldmann visual field examination was full OD and revealed an inferior arcuate defect OS. CT scan of the head demonstrated “postsurgical changes only” and a diagnosis of “anterior ischemic optic neuropathy” OS was made. In August 1996, the patient was referred to the neuro-ophthalmology service at Baylor College of Medicine with painless progressive loss of vision OS over the previous 2 years. Visual acuity was 20/20 in the right eye (OD) and count fingers OS. Again, there was an afferent pupillary defect and optic atrophy OS. Visual field testing showed a superotemporal defect OD and a central island OS. Cerebral angiography did not reveal an aneurysm. CT scan of the head showed a ring-enhancing mass in the parasellar region (Figure 1). The patient underwent craniotomy and, at surgery, a cystic mass was identified. The mass contained a “cheesy-like” material with several pieces of muslin floating freely within the cavity. The results of Gram stain and culture of this material were negative. Surgical decompression with excision and drainage of the mass was performed. Histopathological examination of the mass revealed dense areas of scarring and a polymorphic infiltrate composed of lymphocytes, plasma cells, neutrophils, and numerous lipid-laden histiocytes. Multiple foci of necrosis with microabscesses were present. Under polarized light, scattered birefringent foreign bodies were observed (Figure 2). Foci of epithelioid histiocytes and multinucleated giant cells were also noted. At last follow-up visit in February 1997, the patient’s vision was 20/20 OD and 3/200 OS. Visual field examination remained unchanged.

Description of a new disease on Erythrina sp. in Martinique (French West Indies) and preliminary characterization of the causal agent as a novel Erwinia species

In spring 1995, symptoms of partial defoliation were observed on Erythrina indica var. fastigiata trees, commonly used as windbreaks in banana plantations in Martinique (French West Indies). Browning of the bark surface was consistently observed at the base of defoliated branches. Bacteria were isolated as nearly pure cultures from typical necrotic lesions on the bark. Results of Gram stain, staining of flagella and biochemical tests indicated that all isolates belonged to the Enterobacteriaceae, and to the genus Erwinia. Numerical analysis of the results of 48 biochemical properties showed that Erwinia isolates from diseased erythrina trees constituted a homogenous phenotypic cluster, and that, although weakly pectolytic, these isolates were closely related to pectolytic Erwinia species: E. carotovora ssp. betavasculorum and ssp. wasabiae, and E. cacticida. However, they could be clearly distinguished by different biochemical characteristics from type strains of known plant pathogenic species of Erwinia, Pantoea and Enterobacter. Under greenhouse conditions, the isolates were pathogenic to Erythrina indica var. fastigiata cuttings, but not to banana and pineapple, which are major crops in Martinique.

Community-Acquired Pneumonia: An Overview.

Community-acquired pneumonia (CAP) accounts for a significant number of hospitalizations and outpatient visits, as well as substantial health care expenditures. CAP is particularly common among the elderly who account for more than 90% of deaths due to pneumonia. Streptococcus pneumoniae is believed to be the most common microbial etiology of CAP, but recent studies suggest that the atypical pathogens may be more common than previously thought, particularly among ambulatory patients. Recent studies have provided data regarding risk of mortality and process of care and outcomes. Increasing resistance among strains of S. pneumoniae has impacted the approach to the empiric therapy of CAP. The Infectious Diseases Society of America published guidelines for the evaluation and management of CAP this past year. Pathogen-specific therapy guided by the results of sputum gram stain and culture is emphasized. Despite enthusiasm for practice guidelines and clinical pathways, there remains insufficient published data to determine their impact on quality and cost of care in patients with CAP.

Evaluation of the Cytocentrifuge Gram Stain as a Screening Test for Bacteriuria in Specimens From Specific Patient Populations

To assess the usefulness of the cytocentrifuge Gram stain as a urine screening test in the clinical microbiology laboratory for the elimination of culture for screen-negative specimens, we compared the results of the cytocentrifuge Gram stain to the results of culture for 1,171 urine specimens. The data were analyzed separately for specimens from males (inpatients) and females (inpatients and outpatients), as well as for catheterized and voided specimens. Overall, the cytocentrifuge Gram stain had excellent negative predictive value (97.7%) and sensitivity (92.3%) at a culture threshold of 10(5) colony-forming units per milliliter or more. The negative predictive value and sensitivity decreased at lower culture thresholds in all populations. The negative predictive value decreased most markedly for female outpatients. Because of low positive predictive value and specificity, this test is not reliable as a sole indicator for presumptive therapy in many cases with positive results. If its limitations are recognized, the cytocentrifuge Gram stain is a useful screening test for the rapid exclusion of bacteriuria.

The histopathology of closed and open comedones of Favre-Racouchot disease.

To determine the distinction between a comedo and an infundibular cyst of Favre-Racouchot disease. A university hospital. From the 8 patients included in the study, 19 cysts and comedones were evaluated. The distinguishing features between the cysts and comedones of Favre-Racouchot disease. All lesions were histologically indistinguishable from the primary comedones of acne vulgaris, except for the presence of a marked actinic elastosis in the surrounding dermis. The presence of a variable number of hair shafts and an abundant amount of bacteria, which was positive in the results of Gram staining and periodic acid-Schiff reaction and intermingled with sebum and eosinophilic laminated horny material within the dilated infundibulum, characterizes a comedo and differentiates it from an infundibular cyst. The cysts and comedones of Favre-Racouchot disease are closed and open comedones. They can be easily differentiated from an infundibular cyst by the histopathologic features rather than by the connection to the surface.

Corneal lipofuscinosis--clinicopathologic study of 10 patients

Lipofuscin pigments are considered indigestible residues of lysosomal activity associated with aging. We present the clinical and histopathological features of ten patients with corneal lipofuscinosis. Ten patients (five female, five male, mean age 62 years, range 53 to 77 years) underwent penetrating keratoplasty for vascularized corneal scars. The clinical diagnoses were herpes simplex keratitis (5), zoster keratitis (1), phlyctenular keratitis (1), immunologic graft rejection (2) and corneal injury (1). The mean duration of disease was 6.5 years (range 3 to 11 years). On slit lamp examination both linear and diffuse deposits of yellow pigment were noted in the corneal stroma. All corneal buttons were processed for histopathologic and electron microscopic studies. The areas of yellowish pigmentation in the corneal stroma corresponded histopathologically to clusters of macrophages, keratocytes and occasional giant cells containing PAS-positive granules. The granules measured 1 to 3 micrometers and were also present extracellularly. Results of Gram stain were negative, but the material showed vivid autofluorescence. Corneal lipofuscin can be detected at the slit lamp as focal or diffuse yellowish deposits in both the superficial and deep corneal stroma of patients with long-standing keratitis. This is in contrast to corneal iron deposits, which appear as yellowish pigment in the corneal epithelium. The identification of corneal lipofuscin is possible using histochemical and autofluorescent studies. Further studies should address whether corneal lipofuscin predisposes to suture loosening.

GRAM STAIN DETECTION OF INFECTION DURING REVISION ARTHROPLASTY

We reviewed 194 revision arthroplasties of the hip and knee performed over a ten-year period. The results of intraoperative Gram staining were available in 169 (87%). Thirty-two were found to be infected (11 hips and 21 knees) and 137 had no evidence of infection. Intraoperative Gram staining was negative in all 169 cases. The method therefore had a sensitivity of 0% for detecting infection. We conclude that the absence of organisms on intraoperative Gram staining during revision arthroplasty does not confirm the absence of infection.

Bacteriologic diagnosis of respiratory tract infection

The use of the Gram stain for determination of the presence of bacteria in respiratory secretions is described. Success of the procedure depends on the use of fresh samples of high cellular quality. The Gram stain can be used to distinguish the presence (among other organisms) of Streptococcus pneumoniae, Haemophilus influenzae, Branhamella catarrhalis enterobacteria and Pseudomonas. This paper also discusses the use of sputum samples for bacteriologic culture and the value of bacterial counts in expectorated sputum, and describes the use of transtracheal aspiration and transthoracic aspiration puncture. Finally, it considers the optimum procedures for the testing of antibiotic susceptibility of presumptive pathogens isolated from the lower respiratory tract.

An approach to the identification of the pathogens of bacterial meningitis by the polymerase chain reaction

A combination of universal and species-specific primers was used to detect and differentiate by nested polymerase chain reaction (PCR) the four species most commonly causing bacterial meningitis. Primers recognising conserved sequences in the 16S and 23S ribosomal RNA genes were employed to amplify the 16S-23S spacer region from Neisseria meningitidis, Haemophilus influenzae (type b), Streptococcus pneumoniae, and Streptococcus agalactiae (group B streptococcus). The sequence of the most abundant spacer product was determined in each case and used to deduce species-specific primers. A nested PCR using universal primers in the first round and a species-specific primer in the second were able to detect and distinguish between the four common pathogens, in the presence of human DNA. Streptococcus pneumoniae DNA was detected in the cerebrospinal fluid of a meningitis patient with negative culture and Gram-stain results.