Srujana Mohanty

Antibiogram pattern and seasonality of Salmonella serotypes in a North Indian tertiary care hospital

The antibiogram pattern and seasonal distribution of Salmonella serotypes were analysed retrospectively over a 6-year period from January 1999 to December 2004. Blood cultures received in the Bacteriology Laboratory were processed by standard procedures and the Salmonella spp. isolates were identified with specific antisera and standard biochemical tests. Antimicrobial susceptibility testing was carried out by a standard disc diffusion method and the minimum inhibitory concentration (MIC) of ciprofloxacin for 332 representative Salmonella isolates was determined by E test. Salmonella Typhi (75.7%) was the predominant serotype among 830 Salmonella spp. isolated during the study period followed by S. Paratyphi A (23.8%). The maximum number of enteric fever cases occurred during April-June (dry season) followed by July-September (monsoon season). There was a decrease in multidrug-resistant (MDR) S. Typhi, but MDR S. Paratyphi A isolates increased. There was also a dramatic increase in nalidixic acid-resistant isolates. All isolates were susceptible to third-generation cephalosporins and ciprofloxacin except one S. Typhi strain which demonstrated high-level ciprofloxacin resistance with a MIC of 16 mug/ml. A knowledge of the seasonal distribution and antibiotic resistance pattern of Salmonella in a particular geographical region is helpful in the delineation of appropriate control measures required for prevention of enteric fever.

Emerging Leptospirosis, North India

To the Editor: We read with interest the article, The Changing Epidemiology of Leptospirosis in Israel, published in volume 7, no. 6 (1). Leptospirosis, a septicemic zoonosis with multisystemic involvement, is caused by the pathogenic strains of Leptospira interrogans. Rural farm workers are at high risk for leptospirosis, and it can be a significant public health problem when water and food safety are not ensured. Several epidemics of leptospirosis have occurred on Andaman and Nicobar islands and in southern and western parts of India during the past century (2). The organism has been detected in farm animals in many parts of the country (3); however, human infections have been more or less localized. In 1998, researchers warned that, unless adequate public health measures were initiated, large leptospirosis epidemics were possible in areas where the disease had not been previously reported (4). In addition, they recommended improving clinical diagnosis and conducting systematic epidemiologic studies to control of the disease (4). The true incidence of human leptospirosis in northern India is not known either because of a lack of awareness on the part of the treating physicians or the lack of diagnostic techniques. In 1966, human leptospirosis was reported in Delhi, a state in northern India (5). In a 1966 study (5), sera from persons with pyrexia and jaundice were tested by the agglutination lysis test for leptospiral antibodies. Of 93 serum specimens from persons with pyrexia cases, 3 were positive (1 with L. icterohemorrhagica and two with L. canicola); of 43 serum specimens from persons with jaundice, 3 were positive (2 with L. icterohemorrhagica and 1 with L. icterohemorrhagica and L. pomona). No other study on leptospirosis has been done in the region, and no data are available concerning the problem. To assess the current status of transmission in Delhi and its adjoining areas, we conducted a systematic study for the diagnosis of leptospirosis in our hospital from April 2000 to March 2001; case definition criteria suggested in a previous study (4) were used. A case was defined as a person with fever, headache, and myalgia and more than two of the following symptoms: jaundice, oliguria, respiratory symptoms (cough, hemoptysis, and breathlessness), hemorrhagic manifestations (hematemesis, bleeding gums, and subconjunctival hemorrhage), and signs of meningeal irritation and convulsion. Seventy-five patients (44 male patients; 3–73 years of age) satisfied the inclusion criteria. In addition to clinical evaluation and assessment for other diseases, leptospirosis was investigated by the following laboratory methods: isolation of Leptospira interrogans, direct visualization of the organism under dark-field microscopy, and enzyme-linked immunosorbent assay (ELISA) for Leptospira immunoglobulin (Ig) M antibody (Serion Immunodiagnostica GmbH, Wurzburg, Germany). Per manufacturer’s specifications, the sensitivity, specificity, positive predictive value, and negative predictive value of this kit are 96%, 97%, 90%, and 99%, respectively). All blood samples were sent to the Leptospira referral laboratory at the Indian Veterinary Research Institute, Izzatnagar, for microscopic agglutination test (MAT). Eight serovars of L. interrogans (australis, autumnalis, pomona, sejroe, tarassovi, icterohaemorrhagica, hebdomadis, and patoc) were tested, and a agglutination titer of more than 1:100 was considered positive. All patients were treated empirically with broad-spectrum antibiotics as well as specific drugs according to the results of investigations. Thirty-two patients (42.6%) had a positive ELISA test for Leptospira IgM antibody. The results of MAT were positive in 21 (65.6%) of the 32 ELISA-positive serum samples. Serum specimens from 11 patients reacted with a single serovar, and specimens from 10 patients reacted with more than one serovar. Among the pathogenic species, Leptospira antibodies were detectable by MAT predominantly against L. sejroe (7 of 21), followed by L. icterohaemorrhagica (6 of 21), L. hebdomadis (4 of 21), and L. tarassovi (4 of 21). Leptospira antibodies were also detectable against L. autumnalis (3 of 21), L. australis (2 of 21), and L. pomona (1 of 21). Against L. patoc, MAT could detect antibodies in six samples. The organism could not be isolated in culture or visualized under dark-field microscopy in any of the specimens. Of the 43 case-patients with ELISA-negative specimens, alternative diagnoses were established for 40 on the basis of various laboratory investigations. In five of the case-patients with ELISA-positive specimens, coinfection with other pathogens was detected, including Salmonella typhi (one case) by a positive Widal test, hepatitis C virus by positive ELISA (two cases), and Plasmodium falciparum (two cases) by a positive smear. Five patients, including three who were ELISA positive for Leptospira, died. The highest number of ELISA-positive serum samples (21 of 32) were obtained in August and September 2000, suggesting an epidemic. Epidemiologic investigation of leptospirosis is often hampered by the difficulty of making a definitive microbiologic diagnosis. Isolation of leptospira from clinical samples provides a definitive diagnosis; however, the value of culture is limited because samples have to be collected before the administration of antibiotics, and culturing requires prolonged incubation. Demonstration of typical motility of leptospira under dark-ground illumination in clinical samples, though helpful in early diagnosis, has low sensitivity and depends on the technician’s opinion. Measurement of IgM antibodies against Leptospira by ELISA has emerged as a reliable diagnostic test with good specificity and sensitivity (6). The probability of achieving a positive serologic test increases with the duration of disease, and good correlation between results of MAT and ELISA has been reported by Cumberland et al. (7). MAT has emerged as a dependable diagnostic tool for leptospirosis (next to isolation) by providing serovar specific diagnosis. However, a large number of serovars of L. interrogans exist, and maintaining large numbers of organisms for MAT is difficult for most laboratories. Moreover, MAT may fail to detect antibodies when specific serovars are not used. In this study, the ELISA-positive samples, for which MAT results were negative, may have been caused by infection with serovars other than those used in this study. Because of the problems with methods, leptospirosis is grossly underdiagnosed. Leptospira organisms require humid weather for their survival. Rodents and domestic animals (i.e., cattle and dogs) harbor leptospires and shed the bacteria in urine; they may disseminate the organism in the rain and drinking water sources. Humans frequently come into contact with contaminated water during floods; the number of cases is higher during and after heavy rainfalls. We found that the peak incidence of the disease was during August and September, the monsoon season, which may explain the high incidence of seropositivity during this period. Though the organism has been detected in farm animals in northern India, human leptospirosis has not been considered a major public health problem, probably because transmission is low in arid weather conditions. As a result of 13 consecutive monsoons of above-average strength in India, changes in the environment may be promoting the transmission of this organism. Recently, two other regions in northern India, Chandigarh (8) and Varanasi (9), have reported a Leptospira seroprevalance rate of 8.8% and 21.74%, respectively. Our study supports the warning from other researchers regarding the threat of leptospirosis in areas such as northern India. Preventive measures should be initiated and rapid and definitive diagnostic tests must be developed.

Brain Abscess due to Enterococcus avium

We report the first case of brain abscess due to Enterococcus avium in a 19-year-old man with chronic otitis media since childhood. The patient presented to the emergency department in a comatose condition. Contrast-enhanced brain computed tomography scan showed a hypodense area with ring enhancement in the right temporal lobe and mass effect with subfalcine and transtentorial herniation. Emergency temporal burr hole operation was performed and pus drained out, but the patient succumbed to his illness. Culture of the aspirated pus yielded growth of gram-positive cocci identified as E avium, an infrequent pathogen of human infections. The association of E avium with brain abscess further extends the clinical spectrum of this rare pathogen.

Seasonality and antimicrobial resistance pattern of Vibrio cholerae in a tertiary care hospital of North India.

We retrospectively analysed the seasonal distribution of cholera and the antimicrobial resistance pattern of Vibrio cholerae isolates over a 5-year period from January 1998 to December 2002. Of 3213 stool specimens processed from 3213 patients with acute watery diarrhoea during this period, 431 samples (13.4%) were found positive for V. cholerae. There were 423 V. cholerae Ol biotype E1Tor, 2 V. cholerae 0139 and six isolates of non-01 non-0139. The highest number of cholera cases occurred in May-June followed by July-August. Cases started appearing in April for all years except in the year 2002 when three cases occurred in the first week of March. A large number (90.25% strains) were resistant to at least one antibiotic.

Meningitis due to Escherichia vulneris

was used to localize the lesion. The lesion was located relatively deep into the brainstem but was closer to the posterior surface and was to the right of the midline. An incision was taken in the region of the pontomedullary junction in the midline at the level of the lesion. Blunt dissection was used in a vertical direction within a limit of about 4-5 mm using number 7 Rhoton microdissector. The lesion was encountered at a depth of about 4mm. The lesion was then carefully dissected from the surrounding structures using bipolar diathermy, as well as sharp and blunt dissection. With this technique, it was easy to deliver the tissue as a whole through the small opening. Postoperative imaging confirmed complete resection of the lesion (Figure 1b). Following surgery, the patient developed vertical nystagmus and his diplopia persisted. His left hemiparesis and unsteady gait improved. Intracranial cavernomas constitute about 5-13% of intracranial vascular malformations and 10-30% of these are located in the posterior cranial fossa. Cavernomas often have a rim of gliosis with haemosiderin deposit surrounding it following previous bleeding, thus making surgical dissection from adjoining brain tissue relatively easy. However, when the lesions are located deep in the brain parenchyma, the dissection has a potential risk of injury. Thus, a safe route of access is crucial. The incision on the brainstem and direction of further dissection within it should take into consideration the orientation of the surrounding structures. In the presented case, the lesion was located relatively deep in the brainstem from the surface and was to the right of the midline. A direct incision over the site of location of the lesion could have resulted in damage to underlying structures like facial colliculus, vestibular nuclei and hypoglossal nucleus. Considering the location in proximity to the midline, an incision simulating midline myelotomy was made. Neuronavigation technique with intraoperatively acquired MRI images helped to localise the lesion. The incision in the brainstem and the further dissection were done in a vertical direction to protect the adjoining critical neural structures.

Bacteriology of parapneumonic pleural effusions in an Indian hospital

In addition to adequate drainage, successful management of complicated pleural effusions and empyema also requires prompt and aggressive treatment with appropriate antibiotics, for which knowledge of the causative organisms involved is essential. In this study (January 2001 to December 2004), the bacteriological profile of patients with pleural effusion/empyema admitted to our hospital was analysed. A total of 2906 pleural fluid samples were received, of which 459 (15.8%) samples were culture positive. The number of Gram-negative and Gram-positive organisms isolated was 412 (86.4%) and 65 (13.6%), respectively. The most frequent Gram-negative organisms were Acinetobacter spp. (27.7%), Pseudomonas aeruginosa (23.9%) and Klebsiella spp. (12.6%). Staphylococcus aureus (9.6%) was the most frequent Gram-positive organism. Most of the pathogens showed resistance to multiple antibiotic agents.

Role of Aprotinin in the Management of Experimental Fungal Keratitis

In an experimentally induced Aspergillus fumigatus fungal keratitis in 20 rabbits, aprotinin, an antiplasmin agent, was studied to find out its role as an adjuvant when given along with other established antifungal agents like natamycin and fluconazole. The 20 rabbits included in this study were randomly divided into four equal treatment groups. Once the ulcer was produced after intrastromal injection of 0.03 ml of A. fumigatus (5.5 × 104 spores/ml), different drugs/agents in combination were used in a randomized manner. These were natamycin (5%) + placebo, natamycin + aprotinin (40 IU/ml), fluconazole (0.3%) + placebo and fluconazole + aprotinin. The rabbits were followed up every day to note the signs of healing which included subsidence of corneal infiltration, disappearance of stromal abscess and subsidence of corneal oedema till complete healing. Results showed that the average healing time was 28.2, 28.4, 49.8 and 49.0 days for natamycin + placebo, natamycin + aprotinin, fluconazole + placebo and fluconazole + aprotinin, respectively. It suggests that aprotinin as an adjuvant has no definite role in the management of fungal keratitis. The plasminogen activator-plasmin system which is inhibited by aprotinin may not be the pathway through which filamentous fungi like A. fumigatus cause tissue destruction.

A case of systemic melioidosis: unravelling the etiology of chronic unexplained fever with multiple presentations

Melioidosis, caused by the environmental saprophyte, Burkholderia pseudomallei, is an important public health problem in Southeast Asia and Northern Australia. It is being increasingly reported from other parts, including India, China, and North and South America expanding the endemic zone of the disease. We report a case of systemic melioidosis in a 58-year-old diabetic, occupationally-unexposed male patient, who presented with chronic fever, sepsis, pneumonia, pleural effusion and subcutaneous abscess, was undiagnosed for long, misidentified as Pseudomonas aeruginosa infection elsewhere, but was saved due to correct identification of the etiologic agent and timely institution of appropriate therapy at our institute. A strong clinical and microbiological suspicion for melioidosis should be considered in the differential diagnosis of acute pyrexia of unknown origin, acute respiratory distress syndrome and acute onset of sepsis, especially in the tropics.

Pleural empyema due to Group A beta-hemolytic streptococci in an adult

palmoplantar pigmentation. Postgrad Med J 2001;77:268 & 277. 3. Cherian S. Palmoplantar pigmentation: A clue to Alkaptonuric ochronosis. J Am Acad Dermatol 1994:30:284-5. 4. Suwannarat P, Phornphutkul C, Bernardini I, Turner M, Gahl WA. Minocycline-induced hyperpigmentation masquerading as alkaptonuria in individuals with joint pain. Arthritis Rheum 2004;50:3698-701. 5. Bruce S, Tschen JA, Chow D. Exogenous ochronosis resulting from quinine njections. J Am Acad Dermatol 1986;15:357-61. PaCO2 27.6 mmHg and PaO2 87.2 mmHg. A chest radiograph showed a small left pleural effusion. Thoracocentesis was performed and thick, foul smelling, cloudy yellowish pus aspirated and sent for bacterial culture along with a blood sample. The patient was administered parenteral antibiotics (ceftriaxone, amikacin and vancomycin) and was also started on parenteral insulin for control of the blood sugar level. However, the chest pain and breathlessness worsened over the next 12 hours. A computed tomograph (CT) scan revealed a well-defined sharply marginated collection in the left hemithorax with thickened smooth walls and loculated effusion (155×139× 84 mm).

Liver Abscess due to Streptococcus constellatus in an Immunocompetent Adult: A Less Known Entity

BACKGROUND Pyogenic liver abscesses (PLAs) are an uncommon, but potentially life threatening infection. We report a case of PLA due to Streptococcus constellatus, a member of the Streptococcus anginosus group (SAG) bacteria, commonly found as commensals of the oropharyngeal, gastrointestinal and genitourinary flora. CASE The patient, a 42-year-old man with no premorbidities, non-smoker and non-alcoholic, presented to our hospital with high-grade fever associated with chills and rigors and right upper quadrant pain of one month duration. Culture of the ultrasound-guided liver aspirate yielded a pure growth of S. constellatus subspecies constellatus identified by conventional biochemical tests. In a standard antimicrobial disk-diffusion test, the isolate was susceptible to cefepime, cefotaxime, ceftriaxone, vancomcyin, levofloxacin, clindamycin and linezolid. Treatment with parenteral ceftriaxone alongwith appropriate surgical management led to resolution of the abscess with no recurrence of infection at three months follow-up. CONCLUSIONS The pathogenic potential of SAG has generally been disregarded because of the commensal nature of these microorganisms; however, streptococci belonging to this group have been increasingly reported as relevant pathogens in abscesses and blood cultures. An underlying condition, such as diabetes, cirrhosis or cancer or some medical manipulation, such as dental extraction, acupuncture, or hemorrhoidectomy is associated with the majority of patients with SAG abscess. However, the present case highlights the need to include S. constellatus and other members of the SAG while investigating for etiology of PLA, even in immunocompetent adults.