Infections that occur during the hospital stay, not present at the time of hospitalization, but become clinically apparent during hospitalization or after discharge from the hospital. As a general rule new infection occurring after 48 hrs of hospitalization can be considered as nosocomial. Mostly nosocomial infections are caused by Bacteria but Viruses, Chlamydia, Fungi and Protozoa can also cause such infections. Mostly nosocomial infections occur in Teaching hospitals.
Nosocomial infections acquired in the hospitals did not become clinically evident until hospital discharges. Infections in neonates that result from the passage through the birth canal, and infections that are associated with complications or extension of infection already present at the time of admission are not considered as nosocomial. Nosocomial infections and antimicrobial resistance are topics that have been intensely studied in human medicine because of their significant impact on human health. In recent years, concerns have been raised that the use of antibiotics in veterinary medicine, animal husbandry, and agriculture may be contributing to the development of resistance in common bacterial species affecting human beings. Although, there is inadequate proof at this time that the resistance is transmitted from animals to people, but if antibiotics continue to be used indiscriminately in veterinary medicine, veterinarians may find themselves facing regulations restricting the use of some antibiotics. Nosocomial infections have been reported in veterinary medicine and are likely to increase in prevalence with the increase in intensive care practices in many hospitals. Prolonged hospitalization and the use of invasive devices and procedures increase the risk of nosocomial infections. As in human medicine, organisms isolated in the nosocomial infections reported in veterinary patients have an increasingly broad spectrum of antimicrobial resistance. Despite these findings, the use of empiric and prophylactic antibiotic therapy is still widespread in veterinary medicine. Nosocomial infections and antimicrobial resistance may have a serious impact on the future of veterinary medicine, because the cost and ability to treat our patients may be affected by the loss of access to the drugs or effectiveness of antimicrobial drugs. Despite the millions of dollars spent on research to reduce the incidence of nosocomial infections in human patients, the strategies that have consistently proven successful are simple and inexpensive to implement. The most important factor in preventing nosocomial infections is improving the hygienic practices of health care providers. Hand-washing or the use of disposable gloves can dramatically reduce the transmission of bacteria between patients. Aseptic technique should be used in the placement and management of all invasive devices. All staff members should be educated about the risks and symptoms associated with nosocomial infections, so that cases can be detected as early as possible and treated appropriately. We in the veterinary profession have the opportunity to learn from the experiences of the human medical profession and can take steps to prevent the escalation of nosocomial infections and their impact on our profession.
Types of Nosocomial infections
Various types of hospital born infections are as under:
Causes of Nosocomial infection
Opportunistic infections are the main causes in which the various groups of pathogens included are as under
|Sources of opportunistic pathogen in hospitals||
Risk factors for nosocomial infection
|Hospital workers||Age (very young and very old) patients|
|Animals in hospitals||Prolonged illness|
|Air current||Prolonged use of chemotherapeutic agents|
|Insects and rodents||I/V catheters|
Potential pathogen (Virulence of an agent)
Patient susceptibility (various risk factors of patients such as)
Prolonged illness & Antimicrobial therapy may alter the normal microflora of the Patients & it will lead to reduced colonization resistance. That’s why it leads to colonization of opportunistic pathogen.
Widespread use of antimicrobial therapy has prolonged the survival of critically ill patients. As a result high risk patients and having extended hospitalization are more opportunistic for nosocomial infections. In addition to suppressing normal flora, prolonged antimicrobial therapy without antimicrobial sensitivity with broad spectrum antibiotics will lead to antimicrobial drug resistance. Antimicrobial resistance changes with the passage of time and changes with the location among the hospitals as well.
Nosocomial infection in I.C.U
|Vancomycin resistant Enterococci||55%|
|Methicilline resistant Staph aureus||31%|
|3rd gen .cephalosporine resistant E.coli||29%|
|Quinolone resistant p. auruginosa||89%|
Effect of antimicrobials on host resistance to microbial colonization
In veterinary practice multiple drug resistance due to indiscriminate use of antimicrobials such as tetracycline, Aminoglycoside, Chloramphenicol, Cephalothine, Trimethoprim has been observed. Organisms become resistant to many antimicrobials due to frequent use of these antimicrobials in veterinary practice.
Epidemiology of Nosocomial Infection
Nosocomial infections are generally sporadic but may be either epidemic or endemic as well. Epidemic occurrence may result from poor aseptic techniques, poorhouse keeping, crowding of patients and by excessive use of antimicrobials. Spread from patient to patient is facilitated primarily by the hands of hospital personnel. Less frequently spread of infection may occur by contact between patients or by environmental contamination. Antimicrobial therapy without sensitivity increases the population of MDR bacteria in patients facilitating an endemic reservoir.
Nosocomial UTI (Urinary Tract Infection)
Nosocomial UTI must meet at least one of the following criteria; in patients at least one of the following signs with no other recognized cause. Fever, urgency dysuria and positive urine culture pyouria. Urinary tract infections are the most common type of nosocomial infections in human as well as in small animals. Since lower urinary tract is usually colonized with potential pathogen, so before catheterization indwelling urinary catheters should be secured to prevent movement & should be attached to a close drainage system to prevent reflex of contaminated urine. Prophylactic antimicrobials should not be used to prevent the nosocomial urinary tract infections since they promote emergence of resistant organisms. When urine analysis indicates infection an appropriate antimicrobial therapy should be prescribed. Cystocentesis is rationally perfumed for colleting urine sample from dogs and cats and not by catheterization. If catheterization is done for urine collection, it should be done properly in aseptic conditions. We should never do repeated insertion and withdrawing of catheter as it may cause reflux of contaminated urine. The perianal area should be properly washed & covered with antiseptic agents, and catheter should be sterile.
Nosocomial Respiratory Infection
Bacteria may enter into lower respiratory tract by
Aspiration by respiratory tract instrumentation, mechanically assisted ventilation or GI Tract Instrumentation or person’s just undergone surgery and presence of mucin in respiratory secretions. Certain substances like fibronectin inhibit the adherence, but due to malnutrition severe illness or postoperative state can enhance the adherences. Stomach is also a very important reservoir of organisms causing nosocomial pneumonia.
Nosocomial pneumonia is caused mainly by gram negative bacilli. Colonization by gram negative bacilli begins with the adherence of microorganisms to the host epithelial surface (by pilli, cilia, capsule, mucinace, elastase enzyme, surface protein and polysaccharides).
Most important cause of nosocomial pneumonia. Vancomycin is the only drug which can treat MRSA infection but again it will lead to the VRE (vancomycin resistant enterococci). Nosocomial pneumonia is poly microbial. Mortality due to nosocomial pneumonia is 20-50%. In 30% of the pediatric deaths, the number of deaths due to nosocomial pneumonia is 60%. Outbreaks of nosocomial pneumonia occur when contamination of nebulizer (humidification device) occurs.
Administration of antacids and H2 blockers for prevention of nosocomial pneumonia due to gastric colonization. Specific antimicrobial agents are used to prevent nosocomial pneumonia. Local antimicrobial applied as a paste to oropharynx four times in a day can also reduce the bacterial colonization by acidification of food.
Prevention and Control
Staphlococcus aureus, Streptococcus pyogenes, Klebsiella, Pseudomonas.
Factors that Causes Nosocomial Wound Infection
Preoperative hospitalization, duration of operation, magnitude of tissue handling, Location of incision/wound, foreign body, surgical implant, remote infection.
Prevention and Control
Aseptic principle of surgery should be followed consistently. Preoperative antimicrobial prophylaxis must be done 1-2 hours before to attain therapeutic levels. Antimicrobial administration should be carried out even after completion of surgery.
Salmonella, Campylobacter, Giardia, Entamoeba are zoonotic, so hospital personnel should follow good hygiene. The use of prophylactic antimicrobials should not be done because they reduce colonization resistance. Epidemic enteric infection in hospitals is enhanced due to high population density of the patient.
Prevention and Control
Intense cleaning and disinfections should be performed on regular basis. Hospital wards should be constructed with non porous substances. Hospital personnel and patients should be educated.
General Prevention and Control Strategy
The ideal approach to prevent nosocomial infection is to preserve and enhance host defense. Single most important practice that decreases the incidence of nosocomial infections is proper hands washing. Also the judicious and discriminate use of medicaments prevent emergence of drug resistant pathogens. Use of properly sterilized surgical instruments may greatly reduce the incidence of nosocomial infections.
Aasma, N.A., Farzana M, Maleeha A, Rubeena H. and Rubina A. 2009. Nosocomial methicillin-resistant staphylococcus aureus frequency in a tertiary care hospital, lahore, Pakistan. Biomedica. 25: 97 – 100
Ali, A.M, Abbasi S.A, Arif S., Mirza I.A. 2007. Nosocomial infections due to methicillin-resistant Staphylococcus aureus in hospitalized patients. Pak. J. Med. Sci. 23: 593-96.
Bartlett JG, O’Keefe P, Tally FP, Louie TJ, Gorbach SL. 1986. Bacteriology of hospital-acquired pneumonia. Arch Intern Med, 146:868
Blot, Stijn, Depuydt, Pieter, Vandewoude, Koenraad, De Bacquer, Dirk. 2007. Measuring the impact of multidrug resistance in nosocomial infection. Current Opinion in Infectious Diseases. 20 (4): 391-396
CDC. Guidelines for preventing the transmission of tuberculosis in health-care facilities, 1994. MMWR 1994 43 (No. RR-13).
Clinical and Laboratory Standards Institute. 2006. Performance Standards for Anti-Microbial Suceptibility Testing; Sixteenth Informational Supplement (M100- S16). CLSI, Wayne PA; The Committee.
Haley RW, Culver DH, White JW, Morgan WM, Emori TG. 1985. The nationwide nosocomial infection rate: a new need for vital statistics. Am J Epidemiol, 121:159-67.
Haley RW, Culver DH, White JW. 1985. The efficacy of infection surveillance and control programs in preventing nosocomial infections in U.S. hospitals. Am J Epidemiol. 121:182-205.
Horan TC, White JW, Jarvis WR. 1986. Nosocomial infection surveillance, 1984. MMWR. 35(No. 1SS):17SS-29SS.
Martone WJ, Jarvis WR, Culver DH, Haley RW. 1994. Incidence and nature of endemic and epidemic nosocomial infections. In: Bennett JV, Brachman PS, eds. Hospital infections. Boston: Little, Brown, and C C.D.C. Guidelines for preventing the transmission of tuberculosis in health-care facilities. MMWR 43 (No. RR-13).
Schaberg DR, Culver DH, Gaynes RP. 1991. Major trends in the microbial etiology of nosocomial infection. Am. J. Med. 91(suppl 3B):72S-5S.
Steinberg, J.P, Clark C.C., Hackman B.O. 1996. Nosocomial and community-acquired Staphylococcus aureus bacteremias from 1980 to 1993: impact of intravascular devices and methicillin resistance. Clin. Infect. Dis. 23: 255-59.