Nosocomial cross-transmission of Pseudomonas aeruginosa between patients in a tertiary intensive care unit.

Background: Nosocomial infection caused by Pseudomonas aeruginosa (P. aeruginosa) is very common, despite the application of various preventive measures in intensive care units (ICUs) leading to increased morbidity, mortality, prolonged hospital stay, and increased treatment cost. Aim: The aim of the present study is to identify the source of P. aeruginosa infection in patients admitted to tertiary ICU. Materials and Methods: From 200 patients selected randomly, appropriate clinical specimens from different sites were collected and processed for the isolation and identification of the nosocomial pathogens. Surveillance samples from environmental sites and hands of nursing staff were also cultured. Results: P. aeruginosa was found to be the most common pathogen associated with nosocomial infections accounting for 23.3% of all bacterial isolates from different infection sites in the ICU. Serotyping of the clinical isolates and surveillance sample isolates from nurses' hands showed serotype E as the most common serotype. Other serotypes of P. aeruginosa were isolated from environmental cultures such as sinks, floors, walls, tap water, etc. Conclusion: Study revealed a high prevalence of P. aeruginosa infections in the ICU attributed to cross transmission from patient to patient via hands of the nursing staff. Strict enforcement of infection control protocols is essential to minimize the disease burden.

Ventilator-associated pneumonia caused by carbapenem-resistant Enterobacteriaceae carrying multiple metallo-beta-lactamase genes.

Context: Ventilator-associated pneumonia (VAP) is a leading nosocomial infection in the intensive care unit (ICU). Members of Enterobacteriaceae are the most common causative agents and carbapenems are the most commonly used antibiotics. Metallo-beta-lactamase (MBL) production leading to treatment failure may go unnoticed by routine disc diffusion susceptibility testing. Moreover, there is not much information on association of MBL-producing Enterobacteriaceae with ICU-acquired VAP. Therefore, a study was undertaken to find out the association of MBL-producing Enterobacteriaceae with VAP. Settings: This study was conducted in a large tertiary care hospital of North India with an eight-bed critical care unit. Materials and Methods: The respiratory samples (bronchoalveolar lavage, protected brush catheter specimens and endotracheal or transtracheal aspirates) obtained from VAP patients (during January 2005-December 2006) were processed, isolated bacteria identified and their antibiotic susceptibilities tested as per standard protocols. The isolates of Enterobacteriaceae resistant to carbapenem were subjected to phenotypic and genotypic tests for the detection of MBLs. Results: Twelve of 64 isolates of Enterobacteriaceae were detected as MBL producers, bla IMP being the most prevalent gene. Additionally, in three strains, simultaneous coexistence of multiple MBL genes was detected. Conclusion: The coexistence of multiple MBL genes in Enterobacteriaceae is an alarming situation. As MBL genes are associated with integrons that can be embedded in transposons, which in turn can be accommodated on plasmids thereby resulting in a highly mobile genetic apparatus, the further spread of these genes in different pathogens is likely to occur.

Aeromonas caviae septicemia in immunocompetent gastrointestinal carriers

Aeromonas caviae strains have been isolated from blood and stool cultures of three immunocompetent patients, residents of Northern India, who presented with community acquired septicemia without any recent history of diarrhea. Cell culture infectivity test performed on Hep-2 cells have shown substantial degree of invasiveness in the isolated strains. This case unleashes a possibility of asymptomatic gastrointestinal carriage of such strains of A. caviae in a very large population of India, as several areas of India have very high rates of Aeromonas induced acute diarrhea/gastroenteritis (up to 13 percent). It needs to be appraised further in India as well as other countries having high rates of Aeromonas induced acute diarrhea/gastroenteritis.

Hepatorenal syndrome: pathophysiology and treatment.

The hepatorenal syndrome (HRS) is a unique form of acute renal failure with entirely normal renal histology in advanced liver disease. Its diagnosis is made by exclusion of all causes of renal failure and by all the five major criteria as set by the International Ascites Club. The presence of hepatomegaly, poor nutritional status, and oesophageal varices at endoscopy are associated with a high risk of HRS. The liver tests, the Child-Pugh score, are of no value in prediction of its occurrence. Contraction of the effective blood volume, which may lead to renal hypoperfusion with preferential renal cortical ischaemia, is proposed pathogenesis of the condition. Because understanding of the pathogenesis of HRS is incomplete, therapy is supportive only. Optimal fluid management is vital as there is almost invariably a reduction in effective arterial blood volume. Dopamine, frusemide and haemofiltration may be helpful in management of fluid overload but do not affect renal function. TIPS has been used successfully in small series of patients. The vasopressin analog also has been used with early excellent response. The treatment of HRS has been discouraging and the only proven cure for HRS is liver transplantation at this point of time.

Transient achalasia of esophagus in tetanus.

A case with tetanus presenting with progressive dysphagia due to lower esophageal dysfunction is described. A barium swallow at the onset of symptoms showed esophageal dilatation with a smooth tapering at the lower end suggestive of achalasia cardia. The patient recovered from tetanus over the ensuing three weeks; repeat barium swallow at this time was normal, suggesting that esophageal dysfunction was a manifestation of tetanus.